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fcd9d3203e2b913306981620c8b022fd90dd70ea | wikidoc | TMEM249 | TMEM249
TMEM 249 is a protein that in humans is encoded by the C8orfk29 gene.
# Gene
# Locus
TMEM 249 is located near the end of the long arm of chromosome 8 in humans.
# Common aliases
TMEM 249 is also known as C8orfk29.
# Primary sequence & variants/isoforms
The primary sequence found at NCBI and
Aceview on NCBI predicts there are five spliceforms, with four closely resembling one another and the fifth missing a large 5' intron region. Softberry reinforces the Aceview data by predicting five exons, which are seen in four of the five spliceforms of Aceview.
The general structure of the TMEM 249 transcript has a large 5' UTR followed by exon 1, then a large intron followed by exon 2, a small intron then exon 3. The rest of the protein follows exon 3 with a large intron, exon 4 a small intron then exon 5, the 3' UTR.
The primary transcript contains all five exons and produces a protein that is 235 Amino Acids long. Transcript 1 and 2 are translated in the 3' to 5' direction while transcripts 3 through 5 are translated in the 5' to 3' direction. Note that the gene is encoded on the minus strand within the chromosome.
# Homology / Evolution
# Paralogs
The only known paralog of human TMEM 249 is found in the second isoform of the protein in Gorillas. Of the 217 amino acids aligned between gorilla and human TMEM 249, 96% are in complete consensus and 99% are conserved.
# Orthologs
TMEM 249 orthologs includes all groups of life except birds, fungi, archea, protists, and plants. The most distant ortholog, Rozella allomycis, was the most diverged species that qualified as an ortholog. The last shared ancestor between Rozella allomycis and Homo sapiens is the Opisthokonts.
# Homologs
No homologs or homologous domains exist within TMEM 249.
# Phylogeny
No fungi orthologs were found in the search for similar sequences, so it could be assumed that the gene may have arisen in Opisthokonts and proliferated down the animal tree. This would mean the protein diverged too late to evolve through the fungi tree. This would explain why there are no found plant orthologs as the gene would have arose after animals and plants diverged evolutionarily.
# Protein
# Domains and motifs
There are three predicted transmembrane domains. It is unknown whether these transmembrane domains affect the larger structure of the protein complex once properly expressed in tissue. Evolutionary analysis showed that these transmembrane domains are highly conserved across all ortholog taxa.
# Post-translational modifications
There is an area near the 3’ end of the protein that is predicted to be heavily serine phosphorylated. This end of the protein is likely on the cytosolic half of the protein and serves in some activation function of a pathway.
# Secondary structure
TMEM249 has a highly varied structure. Prediction data supports alternating regions of beta sheets and alpha helices. These predictions may support a beta barrel or "helix barrel" through the membrane made up of multiple protein monomers of TMEM249.
# Expression
# Promoter
The promoter region was found using Eldorado from Genomatix.de (source), the region occupies a region upstream of the 5’ region of TMEM 249 on the minus strand of chromosome 8. This promoter binds a number of transcription factors as determined by Eldorado at Genomatix.de.
# Tissue Expression
TMEM 249 expression is present at a high level in a wide variety of human tissues. GEO tissue profiles for this protein show that this protein is present in a wide variety of locations within the human body. The human protein atlas claims an even wider expression scope for this protein(source).
# Function / Biochemistry
# Interacting Proteins
There were no known protein interactions for TMEM 249.
# Clinical Significance
TMEM249 has no known link to medical disease.
# Mutations
There exist a number of SNPs for TMEM 249 in humans. The mutations are scattered for the most part, with the largest changes in amino acids occurring in the domain of unknown function. | TMEM249
TMEM 249 is a protein that in humans is encoded by the C8orfk29 gene.
# Gene
# Locus
TMEM 249 is located near the end of the long arm of chromosome 8 in humans.[1]
# Common aliases
TMEM 249 is also known as C8orfk29.[2]
# Primary sequence & variants/isoforms
The primary sequence found at NCBI[3] and
Aceview on NCBI predicts there are five spliceforms, with four closely resembling one another and the fifth missing a large 5' intron region. Softberry reinforces the Aceview data by predicting five exons, which are seen in four of the five spliceforms of Aceview.
The general structure of the TMEM 249 transcript has a large 5' UTR followed by exon 1, then a large intron followed by exon 2, a small intron then exon 3. The rest of the protein follows exon 3 with a large intron, exon 4 a small intron then exon 5, the 3' UTR.
The primary transcript contains all five exons and produces a protein that is 235 Amino Acids long. Transcript 1 and 2 are translated in the 3' to 5' direction while transcripts 3 through 5 are translated in the 5' to 3' direction. Note that the gene is encoded on the minus strand within the chromosome.
# Homology / Evolution
# Paralogs
The only known paralog of human TMEM 249 is found in the second isoform of the protein in Gorillas. Of the 217 amino acids aligned between gorilla and human TMEM 249, 96% are in complete consensus and 99% are conserved.
# Orthologs
TMEM 249 orthologs includes all groups of life except birds, fungi, archea, protists, and plants. The most distant ortholog, Rozella allomycis, was the most diverged species that qualified as an ortholog. The last shared ancestor between Rozella allomycis and Homo sapiens is the Opisthokonts.
# Homologs
No homologs or homologous domains exist within TMEM 249.
# Phylogeny
No fungi orthologs were found in the search for similar sequences, so it could be assumed that the gene may have arisen in Opisthokonts and proliferated down the animal tree. This would mean the protein diverged too late to evolve through the fungi tree. This would explain why there are no found plant orthologs as the gene would have arose after animals and plants diverged evolutionarily.[citation needed]
# Protein
# Domains and motifs
There are three predicted transmembrane domains. It is unknown whether these transmembrane domains affect the larger structure of the protein complex once properly expressed in tissue. Evolutionary analysis showed that these transmembrane domains are highly conserved across all ortholog taxa.
# Post-translational modifications
There is an area near the 3’ end of the protein that is predicted to be heavily serine phosphorylated. This end of the protein is likely on the cytosolic half of the protein and serves in some activation function of a pathway.
# Secondary structure
TMEM249 has a highly varied structure. Prediction data supports alternating regions of beta sheets and alpha helices. These predictions may support a beta barrel or "helix barrel" through the membrane made up of multiple protein monomers of TMEM249.
# Expression
# Promoter
The promoter region was found using Eldorado from Genomatix.de (source), the region occupies a region upstream of the 5’ region of TMEM 249 on the minus strand of chromosome 8. This promoter binds a number of transcription factors as determined by Eldorado at Genomatix.de.
# Tissue Expression
TMEM 249 expression is present at a high level in a wide variety of human tissues. GEO tissue profiles for this protein show that this protein is present in a wide variety of locations within the human body. The human protein atlas claims an even wider expression scope for this protein(source).
# Function / Biochemistry
# Interacting Proteins
There were no known protein interactions for TMEM 249.
# Clinical Significance
TMEM249 has no known link to medical disease.
# Mutations
There exist a number of SNPs for TMEM 249 in humans. The mutations are scattered for the most part, with the largest changes in amino acids occurring in the domain of unknown function. | https://www.wikidoc.org/index.php/TMEM249 | |
ecfacd60a8aa7008cd24d2a67a96635b534d7095 | wikidoc | TMEM260 | TMEM260
TMEM260 is a protein that in humans is encoded by the TMEM260 gene. The function of TMEM260 is not yet clearly understood. TMEM260 is also known as UPF0679, c14orf101, and FLJ0392.
# Gene
## Location
TMEM260 is located on band 22.3 on the small arm of human chromosome 14. The genomic sequence begins at 56,955,072 bp and ends at 57,117,324 bp on chromosome 14. The gene's genomic size is 162,253 bp. The mRNA size for TMEM260 is 4,278 bp. and made up of 15 exons.
## Gene neighborhood
There are four other genes in the neighborhood of TMEM260. Two genes lie upstream of TMEM260, including LINC00520 which is the long intergenic non-protein coding RNA gene 520 gene, and PELI2 which is the pellino E3 ubiquitin protein ligase family member 2 gene. Downstream lies one pseudogene, RPL36AP1, and a gene OTX2, which is the orthodenticle homeobox 2 gene.
## Conserved domains
TMEM260 contains one conserved domain, DUF2723. The domain DUF2723 is conserved back to bacteria and its function is not known.
## Homology
TMEM260 is conserved throughout many species. Orthologs can be found throughout all Eukaryotes, Viridiplantae, Fungi, Protists, Bacteria and Eubacteria. No paralogs have yet been found.
## Isoforms
There are two known isoforms for TMEM260 which produced by alternative splicing. Their uniprot IDs are Q9NX78-1 and Q9NX78-2. Isoform 1 consists of all 707 amino acids in the entire protein sequence, which is made up of 15 exons. Isoform 2 is spliced at amino acid 286 with the 3’ end truncated so that it contains only the first 7 exons in the sequence. It weighs only 30,707 Da.
# Protein
## General properties
The protein TMEM260 consists of 707 amino acids with a predicted molecular weight of 79,536 Da. The protein has an isoelectric point of 8.4. TMEM260 is a multi-pass membrane protein which includes 8 helical transmembrane domains.
## Conservation
The amino acid sequence for TMEM260 is highly conserved in mammals, having around 86% to 100% sequence similarity. Birds, frogs, and lizards also have a high degree of similarity to the human TMEM260 sequence with similarities between 76% and 83%. Fish have between 56% and 66% sequence similarity. Algae have around 52% sequence similarity while diatoms have only 39%. Though mammals contain a very high degree of sequence similarity and other animals show a fairly high degree of sequence similarity, other species such as algae, diatoms, and bacteria have gaps and 3’ end truncations. The segment of the TMEM260 sequence that is highly conserved in organisms as far back as algae, diatoms, and bacteria is the conserved domain DUF2723.
## Post translation modifications
The TMEM260 protein undergoes several different kinds of post translational modifications. These include N-terminal Acetylation, N-Glycosylation, and Phosphorylation. | TMEM260
TMEM260 is a protein that in humans is encoded by the TMEM260 gene. The function of TMEM260 is not yet clearly understood.[1] TMEM260 is also known as UPF0679, c14orf101, and FLJ0392.[2]
# Gene
## Location
TMEM260 is located on band 22.3 on the small arm of human chromosome 14. The genomic sequence begins at 56,955,072 bp and ends at 57,117,324 bp on chromosome 14. The gene's genomic size is 162,253 bp. The mRNA size for TMEM260 is 4,278 bp. and made up of 15 exons.[2]
## Gene neighborhood
There are four other genes in the neighborhood of TMEM260. Two genes lie upstream of TMEM260, including LINC00520 which is the long intergenic non-protein coding RNA gene 520 gene, and PELI2 which is the pellino E3 ubiquitin protein ligase family member 2 gene. Downstream lies one pseudogene, RPL36AP1, and a gene OTX2, which is the orthodenticle homeobox 2 gene.[3]
## Conserved domains
TMEM260 contains one conserved domain, DUF2723. The domain DUF2723 is conserved back to bacteria and its function is not known.
## Homology
TMEM260 is conserved throughout many species. Orthologs can be found throughout all Eukaryotes, Viridiplantae, Fungi, Protists, Bacteria and Eubacteria. No paralogs have yet been found.[4]
## Isoforms
There are two known isoforms for TMEM260 which produced by alternative splicing. Their uniprot IDs are Q9NX78-1 and Q9NX78-2. Isoform 1 consists of all 707 amino acids in the entire protein sequence, which is made up of 15 exons. Isoform 2 is spliced at amino acid 286 with the 3’ end truncated so that it contains only the first 7 exons in the sequence. It weighs only 30,707 Da.[2]
# Protein
## General properties
The protein TMEM260 consists of 707 amino acids with a predicted molecular weight of 79,536 Da. The protein has an isoelectric point of 8.4. TMEM260 is a multi-pass membrane protein which includes 8 helical transmembrane domains.[1][2]
## Conservation
The amino acid sequence for TMEM260 is highly conserved in mammals, having around 86% to 100% sequence similarity. Birds, frogs, and lizards also have a high degree of similarity to the human TMEM260 sequence with similarities between 76% and 83%. Fish have between 56% and 66% sequence similarity. Algae have around 52% sequence similarity while diatoms have only 39%. Though mammals contain a very high degree of sequence similarity and other animals show a fairly high degree of sequence similarity, other species such as algae, diatoms, and bacteria have gaps and 3’ end truncations. The segment of the TMEM260 sequence that is highly conserved in organisms as far back as algae, diatoms, and bacteria is the conserved domain DUF2723.[5][6]
## Post translation modifications
The TMEM260 protein undergoes several different kinds of post translational modifications. These include N-terminal Acetylation, N-Glycosylation, and Phosphorylation.[7] | https://www.wikidoc.org/index.php/TMEM260 | |
650c6abd28bec5af3ce30bd03ae58e97e905549d | wikidoc | TMEM50A | TMEM50A
Transmembrane protein 50A is a protein that in humans is encoded by the TMEM50A gene.
This gene is located in the RH gene locus, between the RHD and RHCE genes. The function of its protein product is unknown; however, its sequence has potential transmembrane domains suggesting that it may be an integral membrane protein. Its position between the RH genes suggests that polymorphisms in this gene may be tightly linked to RH haplotypes and may contribute to selective pressure for or against certain RH haplotypes.
# Gene
The TMEM50A gene is located on chromosome 1 p36.11 in the human (homo sapiens) genome. Its mRNA sequence is 2284 base pairs in length and includes seven exons. The coding sequence is from base pairs 151 to 624.
# Protein
The TMEM50A protein is 157 amino acids in length.
## Cellular Location
PSORT II predicts that TMEM50A is most likely found in the cells plasma membrane or the endoplasmic reticulum.
## Predicted properties
Through bioinformatic analysis several of TMEM50A's protein properties were predicted.
- Molecular Weight: 17.4 KDal
- Isoelectric point: 5.483
- Post-translational modification: Several post-translational modifications are predicted:
Two serine phosphorylation sites found at amino acids 82 and 84 Residue
One possibleN-Linked Glycosylation Site located at amino acid 74
One possible Tyrosine phosphorylation site
- Two serine phosphorylation sites found at amino acids 82 and 84 Residue
- One possibleN-Linked Glycosylation Site located at amino acid 74
- One possible Tyrosine phosphorylation site
## Structure
The exact structure of TMEM50A is unknown but through the use of several prediction programs, some of its most likely structural components can be assumed.
- TMHMM shows that TMEM50A has four transmembrane regions. This was further confirmed by similar results found in TMEM50A orthologs and the neutral charge found in these regions using SAPS program in Biology Workbench
- By using the PELE program in Biology Workbench along with comparing the results of known protein structures, it can be predicted that TMEM50A has:
Two Alpha Helix structures
Five Beta Sheets
- Two Alpha Helix structures
- Five Beta Sheets
## Splice Sites
Alternative Splice sites were found by BLAT on the UCSC genome browser
TMEM50A has several alternative splices including:
- Removal of exon 2
- Removal of exons 2 and 3
- Removal of exons 2, 3, and 5
- Removal of exon 3
- Removal of exon 5
These alternative splice sites don't affect the reading frame of the sequence and thus may not alter the function of the protein.
## Expression
TMEM50A is expressed in almost all human tissues, but evidence from EST profiles through NCBI, suggests that its expression may be slightly higher in parathyroid tissues and brain tissues. It also seems to be expressed higher during the neonate and juvenile development stages.
## Interacting Proteins
There is one predicted protein that interacts with TMEM50A, C7orf43. This proteins gene is located on chromosome 7 open reading frame 43. Its function is also unknown.
# Future Medical Applications
Investigation of several GEO profiles showed that TMEM50A is highly upregulated in late stage cervical cancer. This may suggest that TMEM50A has some function that may be causing or is caused directly by cervical cancer. Although few studies are available to confirm this idea, more studies may offer suggestions that use TMEM50A for treatment of late stage cervical cancer. | TMEM50A
Transmembrane protein 50A is a protein that in humans is encoded by the TMEM50A gene.[1][2][3]
This gene is located in the RH gene locus, between the RHD and RHCE genes. The function of its protein product is unknown; however, its sequence has potential transmembrane domains suggesting that it may be an integral membrane protein. Its position between the RH genes suggests that polymorphisms in this gene may be tightly linked to RH haplotypes and may contribute to selective pressure for or against certain RH haplotypes.[3]
# Gene
The TMEM50A gene is located on chromosome 1 p36.11 in the human (homo sapiens) genome. Its mRNA sequence is 2284 base pairs in length and includes seven exons. The coding sequence is from base pairs 151 to 624.
# Protein
The TMEM50A protein is 157 amino acids in length.
## Cellular Location
PSORT II predicts that TMEM50A is most likely found in the cells plasma membrane or the endoplasmic reticulum.
## Predicted properties
Through bioinformatic analysis several of TMEM50A's protein properties were predicted.
- Molecular Weight: 17.4 KDal[4]
- Isoelectric point: 5.483[5]
- Post-translational modification: Several post-translational modifications are predicted:
Two serine phosphorylation sites found at amino acids 82 and 84 Residue[6]
One possibleN-Linked Glycosylation Site located at amino acid 74 [6]
One possible Tyrosine phosphorylation site
- Two serine phosphorylation sites found at amino acids 82 and 84 Residue[6]
- One possibleN-Linked Glycosylation Site located at amino acid 74 [6]
- One possible Tyrosine phosphorylation site
## Structure
The exact structure of TMEM50A is unknown but through the use of several prediction programs, some of its most likely structural components can be assumed.
- TMHMM shows that TMEM50A has four transmembrane regions. This was further confirmed by similar results found in TMEM50A orthologs and the neutral charge found in these regions using SAPS program in Biology Workbench
- By using the PELE program in Biology Workbench along with comparing the results of known protein structures, it can be predicted that TMEM50A has:
Two Alpha Helix structures
Five Beta Sheets
- Two Alpha Helix structures
- Five Beta Sheets
## Splice Sites
Alternative Splice sites were found by BLAT on the UCSC genome browser
TMEM50A has several alternative splices including:
- Removal of exon 2
- Removal of exons 2 and 3
- Removal of exons 2, 3, and 5
- Removal of exon 3
- Removal of exon 5
These alternative splice sites don't affect the reading frame of the sequence and thus may not alter the function of the protein.
## Expression
TMEM50A is expressed in almost all human tissues, but evidence from EST profiles through NCBI, suggests that its expression may be slightly higher in parathyroid tissues and brain tissues. It also seems to be expressed higher during the neonate and juvenile development stages.
## Interacting Proteins
There is one predicted protein that interacts with TMEM50A, C7orf43. This proteins gene is located on chromosome 7 open reading frame 43. Its function is also unknown.
# Future Medical Applications
Investigation of several GEO profiles showed that TMEM50A is highly upregulated in late stage cervical cancer. This may suggest that TMEM50A has some function that may be causing or is caused directly by cervical cancer. Although few studies are available to confirm this idea, more studies may offer suggestions that use TMEM50A for treatment of late stage cervical cancer. | https://www.wikidoc.org/index.php/TMEM50A | |
9e8d988251a7cc9a2246e3e205df485e4b8db9e5 | wikidoc | TMEM63A | TMEM63A
Transmembrane protein 63A is a protein that in humans is encoded by the TMEM63A gene. The mature human protein is approximately 92.1 kilodaltons (kDa), with a relatively high conservation of mass in orthologs. The protein contains eleven transmembrane domains and is inserted into the membrane of the lysosome. BioGPS analysis for TMEM63A in humans shows that the gene is ubiquitously expressed, with the highest levels of expression found in T-cells and dendritic cells.
# Gene
## Overview
TMEM63A is located on the negative DNA strand of chromosome 1 at location 1q42.12, spanning base pairs 226,033,237 to 226,070,069. Aliases include KIAA0489 and KIAA0792. The human gene product is a 4,469 base pair mRNA with 25 predicted exons. There are 9 predicted splice isoforms of the gene, three of which are protein coding. Promoter analysis was carried out using El Dorado through the Genomatix software page. The predicted promoter region spans 971 base pairs, from 226,070,920 to 226,069,950 on the negative strand of chromosome 1.
## Gene neighborhood
TMEM63A is located adjacent to the EPHX1 gene on the positive sense strand of DNA on chromosome 1, as well as the LEFTY1 gene on the negative sense strand. Other genes in the same area on chromosome 1 include SRP9 and LEFTY3 on the positive strand, and MIR6741 and PYCR2 on the negative strand.
## Expression
TMEM63 is ubiquitously expressed throughout the human body at varying levels, occurring with the highest relative prevalence in CD 8+ T cells and CD 4+ T cells. Moderate relative levels of expression are also observed throughout the brain, particularly in the occipital lobe, parietal lobe, and pancreas. Analysis of TMEM63A expression in the mouse using BioGPS revealed more variable expression patterns, with the highest expression being seen in the stomach and large intestine. Using the El Dorado program from Genomatix, transcription factor regulation was predicted, which found that ‘’TMEM63A’’ is highly regulated by E2F cell cycle regulators and EGR1, a factor believed to be a tumor suppressor gene with expression in the brain. The 3’ UTR is predicted to be bound by the regulatory element miR-9/9ab.
# Protein
## Properties and characteristics
The mature form of the human TMEM63A protein has 807 amino acid residues with an isoelectric point of 6.925. This is fairly conserved across orthologs. A BLAST alignment revealed that the protein contains three domains: RSN1_TM and two domains of unknown function (DUF4463 and DUF221). RSN1_TM is predicted to be involved in Golgi vesicle transport and exocytosis. DUF4463 is cytosolic and distantly homologous to RNA-binding proteins. This domain can be used to determine the orientation of the protein in the membrane, with the N-terminus of the protein being within the lysosome and the C-terminus located in the cytosol.
Post-translational modification has been determined both experimentally and using bioinformatic analysis. There are two likely sites of glycosylation on the protein: N38 and N450. These were predicted using the NetNGlyc program from ExPASy and the TMEM63A amino acid sequence, as well as the inferred orientation of the protein in the membrane. There are three likely sites of phosphorylation on the protein: S85, S98, and S735, which were predicted using the NetPhos program.
The protein has three isoforms. The mature protein is designated isoform CRA. The other two isoforms are X1 and X2, which are 630 amino acid residues and 468 amino acid residues long, respectively. Isoform X1 is missing the N-terminus of the mature protein, while isoform 2 is missing the C-terminus.
## Interactions
Using text-based information, TMEM63A is thought to potentially interact with six other proteins: EEF1D, FAM163B, CPNE9, TMEM90A, STAC2, HEATR3, and WDR67.
## Function
The function of TMEM63A is not known, although one study found it was in a region likely regulated by mir-200a, linked to epithelial homeostasis. Another found it to be in a quantitative trait locus linked to haloperidol-induced catalepsy.
# Evolutionary history
## Paralogs
TMEM63A has two paralogs: TMEM63B, which is located at 6p21.1, and TMEM63C, which is located at C14orf171. Alignment between them shows that TMEM63C is more closely related to TMEM63B than TMEM63A. A BLAST alignment showed homology of TMEM63A and TMEM63B to proteins as distantly related as plants, while TMEM63C was homologous only as distantly as in drosophila. This indicates that TMEM63C likely diverged from the two early in invertebrates.
## Ortholog space
TMEM63A has a large ortholog space, with homologs present in organisms as distantly related as plants. | TMEM63A
Transmembrane protein 63A is a protein that in humans is encoded by the TMEM63A gene.[1][2][3] The mature human protein is approximately 92.1 kilodaltons (kDa), with a relatively high conservation of mass in orthologs.[4] The protein contains eleven transmembrane domains and is inserted into the membrane of the lysosome.[5][6] BioGPS analysis for TMEM63A in humans shows that the gene is ubiquitously expressed, with the highest levels of expression found in T-cells and dendritic cells.[7]
# Gene
## Overview
TMEM63A is located on the negative DNA strand of chromosome 1 at location 1q42.12, spanning base pairs 226,033,237 to 226,070,069.[3] Aliases include KIAA0489 and KIAA0792. The human gene product is a 4,469 base pair mRNA with 25 predicted exons.[8] There are 9 predicted splice isoforms of the gene, three of which are protein coding. Promoter analysis was carried out using El Dorado[9] through the Genomatix software page. The predicted promoter region spans 971 base pairs, from 226,070,920 to 226,069,950 on the negative strand of chromosome 1.
## Gene neighborhood
TMEM63A is located adjacent to the EPHX1 gene on the positive sense strand of DNA on chromosome 1, as well as the LEFTY1 gene on the negative sense strand.[3] Other genes in the same area on chromosome 1 include SRP9 and LEFTY3 on the positive strand, and MIR6741 and PYCR2 on the negative strand.
## Expression
TMEM63 is ubiquitously expressed throughout the human body at varying levels, occurring with the highest relative prevalence in CD 8+ T cells and CD 4+ T cells.[7][10] Moderate relative levels of expression are also observed throughout the brain, particularly in the occipital lobe, parietal lobe, and pancreas.[10] Analysis of TMEM63A expression in the mouse using BioGPS revealed more variable expression patterns, with the highest expression being seen in the stomach and large intestine.[7] Using the El Dorado program from Genomatix, transcription factor regulation was predicted, which found that ‘’TMEM63A’’ is highly regulated by E2F cell cycle regulators and EGR1, a factor believed to be a tumor suppressor gene with expression in the brain.[9] The 3’ UTR is predicted to be bound by the regulatory element miR-9/9ab.[11]
# Protein
## Properties and characteristics
The mature form of the human TMEM63A protein has 807 amino acid residues with an isoelectric point of 6.925.[4] This is fairly conserved across orthologs. A BLAST alignment revealed that the protein contains three domains: RSN1_TM and two domains of unknown function (DUF4463 and DUF221).[12] RSN1_TM is predicted to be involved in Golgi vesicle transport and exocytosis. DUF4463 is cytosolic and distantly homologous to RNA-binding proteins. This domain can be used to determine the orientation of the protein in the membrane, with the N-terminus of the protein being within the lysosome and the C-terminus located in the cytosol.
Post-translational modification has been determined both experimentally and using bioinformatic analysis. There are two likely sites of glycosylation on the protein: N38 and N450.[13] These were predicted using the NetNGlyc program from ExPASy and the TMEM63A amino acid sequence, as well as the inferred orientation of the protein in the membrane.[14] There are three likely sites of phosphorylation on the protein: S85, S98, and S735, which were predicted using the NetPhos program.[15]
The protein has three isoforms. The mature protein is designated isoform CRA. The other two isoforms are X1 and X2, which are 630 amino acid residues and 468 amino acid residues long, respectively. Isoform X1 is missing the N-terminus of the mature protein, while isoform 2 is missing the C-terminus.[4]
## Interactions
Using text-based information, TMEM63A is thought to potentially interact with six other proteins: EEF1D,[16] FAM163B, CPNE9, TMEM90A, STAC2, HEATR3, and WDR67.[17]
## Function
The function of TMEM63A is not known, although one study found it was in a region likely regulated by mir-200a, linked to epithelial homeostasis.[18] Another found it to be in a quantitative trait locus linked to haloperidol-induced catalepsy.[19]
# Evolutionary history
## Paralogs
TMEM63A has two paralogs: TMEM63B, which is located at 6p21.1, and TMEM63C, which is located at C14orf171.[20] Alignment between them shows that TMEM63C is more closely related to TMEM63B than TMEM63A.[4] A BLAST alignment showed homology of TMEM63A and TMEM63B to proteins as distantly related as plants, while TMEM63C was homologous only as distantly as in drosophila.[12] This indicates that TMEM63C likely diverged from the two early in invertebrates.
## Ortholog space
TMEM63A has a large ortholog space, with homologs present in organisms as distantly related as plants. | https://www.wikidoc.org/index.php/TMEM63A | |
a56cbe8f64a72f86f679236b742a777e054e8cb9 | wikidoc | TMPRSS2 | TMPRSS2
Transmembrane protease, serine 2 is an enzyme that in humans is encoded by the TMPRSS2 gene.
# Function
This gene encodes a protein that belongs to the serine protease family. The encoded protein contains a type II transmembrane domain, a receptor class A domain, a scavenger receptor cysteine-rich domain and a protease domain. Serine proteases are known to be involved in many physiological and pathological processes. This gene was demonstrated to be up-regulated by androgenic hormones in prostate cancer cells and down-regulated in androgen-independent prostate cancer tissue. The protease domain of this protein is thought to be cleaved and secreted into cell media after autocleavage. The biological function of this gene is unknown.
# ERG gene fusion
TMPRSS2 protein's function in prostate carcinogenesis relies on overexpression of ETS transcription factors, such as ERG and ETV1, through gene fusion. TMPRSS2-ERG fusion gene is the most frequent, present in 40% - 80% of prostate cancers in humans. ERG overexpression contributes to development of androgen-independence in prostate cancer through disruption of androgen receptor signaling. | TMPRSS2
Transmembrane protease, serine 2 is an enzyme that in humans is encoded by the TMPRSS2 gene.[1][2]
# Function
This gene encodes a protein that belongs to the serine protease family. The encoded protein contains a type II transmembrane domain, a receptor class A domain, a scavenger receptor cysteine-rich domain and a protease domain. Serine proteases are known to be involved in many physiological and pathological processes. This gene was demonstrated to be up-regulated by androgenic hormones in prostate cancer cells and down-regulated in androgen-independent prostate cancer tissue. The protease domain of this protein is thought to be cleaved and secreted into cell media after autocleavage. The biological function of this gene is unknown.[2]
# ERG gene fusion
TMPRSS2 protein's function in prostate carcinogenesis relies on overexpression of ETS transcription factors, such as ERG and ETV1, through gene fusion. TMPRSS2-ERG fusion gene is the most frequent, present in 40% - 80% of prostate cancers in humans. ERG overexpression contributes to development of androgen-independence in prostate cancer through disruption of androgen receptor signaling.[3] | https://www.wikidoc.org/index.php/TMPRSS2 | |
92ee1323bc1e82d81d72048e75754b2f661c284a | wikidoc | TNFAIP3 | TNFAIP3
Tumor necrosis factor, alpha-induced protein 3 is a protein that in humans is encoded by the TNFAIP3 gene.
This gene was identified as a gene whose expression is rapidly induced by the tumor necrosis factor (TNF). The protein encoded by this gene is a zinc finger protein, and has been shown to inhibit NF-kappa B activation as well as TNF-mediated apoptosis. Knockout studies of a similar gene in mice suggested that this gene is critical for limiting inflammation by terminating TNF-induced NF-kappa B responses.
# Interactions
TNFAIP3 has been shown to interact with TNIP1, TRAF1, TRAF2, IKBKG, TAX1BP1, YWHAB, YWHAZ, TRAF6 and YWHAH.
# Association with rheumatoid arthritis
The TNFAIP3 locus is implicated as a positively associated factor in rheumatoid arthritis (RA). The rs5029937 (T) and the rs6920220 (A) SNPs increase risk of RA by 20 to 40% respectively. A third SNP, rs10499194 (T) is found less often in rheumatoid arthritis but this negative association may not be statistically meaningful.
## Other diseases
An association with infantile onset intractable inflammatory bowel disease has also been reported. | TNFAIP3
Tumor necrosis factor, alpha-induced protein 3 is a protein that in humans is encoded by the TNFAIP3 gene.[1][2]
This gene was identified as a gene whose expression is rapidly induced by the tumor necrosis factor (TNF). The protein encoded by this gene is a zinc finger protein, and has been shown to inhibit NF-kappa B activation as well as TNF-mediated apoptosis. Knockout studies of a similar gene in mice suggested that this gene is critical for limiting inflammation by terminating TNF-induced NF-kappa B responses.[2]
# Interactions
TNFAIP3 has been shown to interact with TNIP1,[3] TRAF1,[4][5] TRAF2,[4] IKBKG,[6] TAX1BP1,[7] YWHAB,[8] YWHAZ,[8][9] TRAF6[5][10] and YWHAH.[8][9]
# Association with rheumatoid arthritis
The TNFAIP3 locus is implicated as a positively associated factor in rheumatoid arthritis (RA). The rs5029937 (T) and the rs6920220 (A) SNPs increase risk of RA by 20 to 40% respectively.[11] A third SNP, rs10499194 (T) is found less often in rheumatoid arthritis but this negative association may not be statistically meaningful.
## Other diseases
An association with infantile onset intractable inflammatory bowel disease has also been reported.[12] | https://www.wikidoc.org/index.php/TNFAIP3 | |
7926ce138573f26e4868946f6802e2aa8875fb88 | wikidoc | TNFSF12 | TNFSF12
Tumor necrosis factor ligand superfamily member 12 also known as TNF-related weak inducer of apoptosis (TWEAK) is a protein that in humans is encoded by the TNFSF12 gene.
# Function
TWEAK was discovered in 1997. The protein encoded by this gene is a cytokine that belongs to the tumor necrosis factor (TNF) ligand family. This protein is a ligand for the FN14/TWEAKR receptor. This cytokine has overlapping signaling functions with TNF, but displays a much wider tissue distribution. Leukocytes are the main source of TWEAK including human resting and activated monocytes, dendritic cells and natural killer cells. TWEAK can induce apoptosis via multiple pathways of cell death in a cell type-specific manner. This cytokine is also found to promote proliferation and migration of endothelial cells, and thus acts as a regulator of angiogenesis.
# Clinical significance
Excessive activation of the TWEAK pathway in chronic injury has been described to promote pathological tissue changes including chronic inflammation, fibrosis and angiogenesis. In chronic liver disease for example TWEAK expression is enhanced and causes hepatic stellate cells, which are key regulators of liver fibrosis, to proliferate. A disease-driving role of the TWEAK pathway has been described in several other diseases as well. For example, NFAT1 regulates the expression of TWEAKR and its ligand TWEAK (this protein) with lipocalin 2 to increase breast cancer cell invasion. | TNFSF12
Tumor necrosis factor ligand superfamily member 12 also known as TNF-related weak inducer of apoptosis (TWEAK) is a protein that in humans is encoded by the TNFSF12 gene.[1][2][3]
# Function
TWEAK was discovered in 1997.[1] The protein encoded by this gene is a cytokine that belongs to the tumor necrosis factor (TNF) ligand family. This protein is a ligand for the FN14/TWEAKR receptor. This cytokine has overlapping signaling functions with TNF, but displays a much wider tissue distribution. Leukocytes are the main source of TWEAK including human resting and activated monocytes, dendritic cells and natural killer cells.[4] TWEAK can induce apoptosis via multiple pathways of cell death in a cell type-specific manner. This cytokine is also found to promote proliferation and migration of endothelial cells, and thus acts as a regulator of angiogenesis.[3]
# Clinical significance
Excessive activation of the TWEAK pathway in chronic injury has been described to promote pathological tissue changes including chronic inflammation, fibrosis and angiogenesis.[5] In chronic liver disease for example TWEAK expression is enhanced and causes hepatic stellate cells, which are key regulators of liver fibrosis, to proliferate.[6] A disease-driving role of the TWEAK pathway has been described in several other diseases as well. For example, NFAT1 regulates the expression of TWEAKR and its ligand TWEAK (this protein) with lipocalin 2 to increase breast cancer cell invasion.[7] | https://www.wikidoc.org/index.php/TNFSF12 | |
b1d513874fa2f55384d468e56305e0f7a9bddc12 | wikidoc | TNX-901 | TNX-901
TNX-901 is a drug being tested at National Jewish Medical and Research Center and other locations across the United States. It is believed that the drug may prevent allergic reactions to small amounts of peanuts, such as those remnant in foods.
The U.S. Food and Drug Administration (FDA) has "fast-tracked" the drug. A drug is given fast-track status if it meets a medical need not currently being met by any medication. TNX-901 is made by a Houston-based company called Tanox; there is a legal dispute against this laboratory that the drug is based on the same anti-asthma sciences paid for by Genentech and Novartis. Trials of the drug were mired in legal battles.
TNX-901 is an anti-IgE antibody. IgE antibody is the receptor responsible for allergic reactions and severe asthma attacks. An anti-IgE antibody binds IgE and prevents it from initiating an allergic reaction. In clinical trials, people who were very allergic to peanuts when they consumed an average of half a peanut were able to consume up to 9 peanuts before they started to have symptoms . Therefore the drug wouldn't cure allergies, but it would prevent reactions from accidental exposure. Note that this study was not done on people allergic enough to die from peanut traces.
A similar drug is already on the market for asthma, under the name Xolair (Omalizumab is the generic name, but it's not generic yet). The problem is that Xolair isn't approved for use in food allergies and TNX-901 can't be released because Xolair's manufacturer sued Tanox for patent infringement. One could obtain a prescription for Xolair without it being approved for use in allergies, but most health insurance will not cover it without FDA approval, meaning it could cost on the order of $1000 a month for a patient.
Recently, TNX-901 has been shelved by its creator Tanox in exchange for money from Genentech and Novartis, and the three companies plan to focus on researching Xolair for use against peanut allergies instead of TNX-901. Xolair entered Phase II trials for use against peanut allergies in July 2004. | TNX-901
TNX-901 is a drug being tested at National Jewish Medical and Research Center and other locations across the United States. It is believed that the drug may prevent allergic reactions to small amounts of peanuts, such as those remnant in foods.
The U.S. Food and Drug Administration (FDA) has "fast-tracked" the drug. A drug is given fast-track status if it meets a medical need not currently being met by any medication. TNX-901 is made by a Houston-based company called Tanox; there is a legal dispute against this laboratory that the drug is based on the same anti-asthma sciences paid for by Genentech and Novartis. Trials of the drug were mired in legal battles.
TNX-901 is an anti-IgE antibody. IgE antibody is the receptor responsible for allergic reactions and severe asthma attacks. An anti-IgE antibody binds IgE and prevents it from initiating an allergic reaction. In clinical trials, people who were very allergic to peanuts when they consumed an average of half a peanut were able to consume up to 9 peanuts before they started to have symptoms [1]. Therefore the drug wouldn't cure allergies, but it would prevent reactions from accidental exposure. Note that this study was not done on people allergic enough to die from peanut traces.
A similar drug is already on the market for asthma, under the name Xolair (Omalizumab is the generic name, but it's not generic yet). The problem is that Xolair isn't approved for use in food allergies and TNX-901 can't be released because Xolair's manufacturer sued Tanox for patent infringement. One could obtain a prescription for Xolair without it being approved for use in allergies, but most health insurance will not cover it without FDA approval, meaning it could cost on the order of $1000 a month for a patient.
Recently, TNX-901 has been shelved by its creator Tanox in exchange for money from Genentech and Novartis, and the three companies plan to focus on researching Xolair for use against peanut allergies instead of TNX-901. Xolair entered Phase II trials for use against peanut allergies in July 2004. | https://www.wikidoc.org/index.php/TNX-901 | |
3c372bfc296ae3295dbc0c604990d76583efbc55 | wikidoc | TP53BP2 | TP53BP2
Apoptosis-stimulating of p53 protein 2 (ASPP2) also known as Bcl2-binding protein (Bbp) and tumor suppressor p53-binding protein 2 (p53BP2) is a protein that in humans is encoded by the TP53BP2 gene. Multiple transcript variants encoding different isoforms have been found for this gene.
# Nomenclature
ASPP2 (amino acid residues 600 –1128) was initially identified as 53BP2 (p53-binding protein 2) in a yeast two hybrid screen using p53 as the bait. Another yeast two hybrid screening in which Bcl-2 was used as the bait gave rise to the discovery of another fragment of ASPP2 (residues 123-1128) and it was called Bbp. The full length ASPP2 (1128 amino acids) was identified later.
# Function
ASPP2 plays a central role in regulation of apoptosis and cell growth via its interactions. ASPP2 regulates TP53 by enhancing the DNA binding and transactivation function of TP53 on the promoters of proapoptotic genes in vivo. ASPP2 binds to wild-type p53 but fails to bind to mutant p53, suggesting that ASPP2 may be involved in the ability of wild-type p53 to suppress transformation. ASPP2 induces apoptosis but no cell cycle arrest.
# Structure
ASPP2 contains several structural and functional domains. Its N-terminus (residues 1–83) has the structure of a β-grasp ubiquitin-like fold. It is followed by a predicted α-helical domain located between aa 123 and 323. and a proline-rich (ASPP2 Pro) domain between aa 674 and 902. The C-terminal part of ASPP2 contains four ankyrin repeats and an SH3 domain involved in protein-protein interactions. ASPP2 is found in the perinuclear region of the cytoplasm.
# Family members
The ASPP family includes ASPP1, ASPP2, and iASPP. The name ASPP stands for apoptosis stimulating protein of p53, the name emphasizes the ankyrin repeats, SH3 domain, and proline-rich domains that characterize this family. The three family members come from different genes but ASPP1 and ASPP2 share a greater sequence similarity than either does with iASPP as the N terminus of iASPP has no homology with ASPP1 and ASPP2. The sequence similarities among ASPP family members indicates that ASPP1 and ASPP2 probably have similar biological functions that differ from that of iASPP. The family plays a key role in apoptosis regulation in the intrinsic and extrinsic apoptotic pathways. ASPP1 and ASPP2 promote, while iASPP inhibits, apoptosis.
# Binding partners
ASPP2 is the ASPP family member with the most known binding partners. The highly conserved C-terminus was first known to bind to p53 through its ankyrin repeats and SH3 domain in 1994 by a yeast two hybrid system and it was called p53 Binding Protein 2 (53BP2). Other binding partners have been discovered through the years, indicating the importance of the ankyrin repeats and SH3 domains for protein-protein interactions. Some of the known binding partners of ASPP2 include BCL2, p63, p73, Hepatitis C virus core protein, Amyloid-b-Precursor Protein-Binding Protein 1 (APP-BP1), YES-Associated Protein (YAP), Adenomatosis Polyposis Coli 2 (APC2), RelA/p65, Protein Phosphatase 1 (PP1) and NFκB (p65)
# Expression
The expression of ASPP2 is encoded by the gene TP53BP2 and is located in the long arm of chromosome 1 at q42.1. Northern-blot analyses showed that the ASPP2/53BP2 mRNA was expressed in many human tissues such as heart, brain, placenta, lung, liver, skeletal muscle, kidney, pancreas, but at varying levels. The highest expression level of ASPP2 was detected in skeletal tissue.
# Clinical significance
ASPP2 was first associated with human cancer when the crystal structure of p53 binding domain bound to the C-terminal ankyrin repeats and SH3 domain of ASP2. All the amino acids of p53 that are important for binding ASPP2 are mutated in human cancers. ASPP2 expression levels have been associated with cellular sensitivity to apoptosis. ASPP2 importance in human malignancies is emphasized by studies that show that downregulation of ASPP2 is commonly found in tumors and carcinoma cells expressing wild type p53, and to a lesser extent mutant p53. For example, it was found to be downregulated in both metastatic and invasive cells as compared to normal breast epithelium. It has been demonstrated the binding of ASPP2 to bcl-2 and p53 and to impede cell cycle progression at G2-M, as well as the fact that binding of ASPP2 to p53 changes the conformation of p53 and increases p53 binding to the promoters of proapoptotic genes such as Bax and PIG-3 but not those of G1-arrest genes such as p21waf1. Single nucleotide polymorphisms of ASPP2 have also shown to be associated with predisposition of gastric cancer development. These could be due to the fact that ASPP2 is also a tumor suppressor as well as an activator of p53.
Levels of expression of ASPP2 are important, high levels of expression play an important role in inducing apoptosis independently of p53, mediated by p63 and p73. The expression is enhanced in response to DNA damage.
On the other hand, silencing of ASPP2 expression by methylation was observed in several human carcinoma cells. | TP53BP2
Apoptosis-stimulating of p53 protein 2 (ASPP2) also known as Bcl2-binding protein (Bbp) and tumor suppressor p53-binding protein 2 (p53BP2) is a protein that in humans is encoded by the TP53BP2 gene.[1][2][3] Multiple transcript variants encoding different isoforms have been found for this gene.
# Nomenclature
ASPP2 (amino acid residues 600 –1128) was initially identified as 53BP2 (p53-binding protein 2) in a yeast two hybrid screen using p53 as the bait.[2] Another yeast two hybrid screening in which Bcl-2 was used as the bait gave rise to the discovery of another fragment of ASPP2 (residues 123-1128) and it was called Bbp.[1] The full length ASPP2 (1128 amino acids) was identified later.[4]
# Function
ASPP2 plays a central role in regulation of apoptosis and cell growth via its interactions. ASPP2 regulates TP53 by enhancing the DNA binding and transactivation function of TP53 on the promoters of proapoptotic genes in vivo.[4] ASPP2 binds to wild-type p53 but fails to bind to mutant p53, suggesting that ASPP2 may be involved in the ability of wild-type p53 to suppress transformation.[2] ASPP2 induces apoptosis but no cell cycle arrest.[4]
# Structure
ASPP2 contains several structural and functional domains. Its N-terminus (residues 1–83) has the structure of a β-grasp ubiquitin-like fold.[5][6] It is followed by a predicted α-helical domain located between aa 123 and 323.[1] and a proline-rich (ASPP2 Pro) domain between aa 674 and 902.[1] The C-terminal part of ASPP2 contains four ankyrin repeats and an SH3 domain involved in protein-protein interactions.[6][7] ASPP2 is found in the perinuclear region of the cytoplasm.[8][9]
# Family members
The ASPP family includes ASPP1, ASPP2, and iASPP. The name ASPP stands for apoptosis stimulating protein of p53, the name emphasizes the ankyrin repeats, SH3 domain, and proline-rich domains that characterize this family.[4] The three family members come from different genes but ASPP1 and ASPP2 share a greater sequence similarity than either does with iASPP as the N terminus of iASPP has no homology with ASPP1 and ASPP2. The sequence similarities among ASPP family members indicates that ASPP1 and ASPP2 probably have similar biological functions that differ from that of iASPP.[10] The family plays a key role in apoptosis regulation in the intrinsic and extrinsic apoptotic pathways.[4][11] ASPP1 and ASPP2 promote, while iASPP inhibits, apoptosis.[12]
# Binding partners
ASPP2 is the ASPP family member with the most known binding partners. The highly conserved C-terminus was first known to bind to p53 through its ankyrin repeats and SH3 domain in 1994 by a yeast two hybrid system and it was called p53 Binding Protein 2 (53BP2).[2] Other binding partners have been discovered through the years, indicating the importance of the ankyrin repeats and SH3 domains for protein-protein interactions. Some of the known binding partners of ASPP2 include BCL2, p63, p73, Hepatitis C virus core protein, Amyloid-b-Precursor Protein-Binding Protein 1 (APP-BP1), YES-Associated Protein (YAP), Adenomatosis Polyposis Coli 2 (APC2), RelA/p65, Protein Phosphatase 1 (PP1)[13] and NFκB (p65)[14]
# Expression
The expression of ASPP2 is encoded by the gene TP53BP2 and is located in the long arm of chromosome 1 at q42.1. Northern-blot analyses showed that the ASPP2/53BP2 mRNA was expressed in many human tissues such as heart, brain, placenta, lung, liver, skeletal muscle, kidney, pancreas, but at varying levels. The highest expression level of ASPP2 was detected in skeletal tissue.[2][10]
# Clinical significance
ASPP2 was first associated with human cancer when the crystal structure of p53 binding domain bound to the C-terminal ankyrin repeats and SH3 domain of ASP2. All the amino acids of p53 that are important for binding ASPP2 are mutated in human cancers.[10] ASPP2 expression levels have been associated with cellular sensitivity to apoptosis.[4] ASPP2 importance in human malignancies is emphasized by studies that show that downregulation of ASPP2 is commonly found in tumors and carcinoma cells expressing wild type p53, and to a lesser extent mutant p53.[15][16] For example, it was found to be downregulated in both metastatic and invasive cells as compared to normal breast epithelium.[16] It has been demonstrated the binding of ASPP2 to bcl-2 and p53 and to impede cell cycle progression at G2-M,[1] as well as the fact that binding of ASPP2 to p53 changes the conformation of p53 and increases p53 binding to the promoters of proapoptotic genes such as Bax and PIG-3 but not those of G1-arrest genes such as p21waf1.[4][17] Single nucleotide polymorphisms of ASPP2 have also shown to be associated with predisposition of gastric cancer development.[17] These could be due to the fact that ASPP2 is also a tumor suppressor as well as an activator of p53.[13]
Levels of expression of ASPP2 are important, high levels of expression play an important role in inducing apoptosis independently of p53, mediated by p63 and p73. The expression is enhanced in response to DNA damage.[18][19]
On the other hand, silencing of ASPP2 expression by methylation was observed in several human carcinoma cells.[15] | https://www.wikidoc.org/index.php/TP53BP2 | |
9b5d9c6407cf4e6279bd638bacb845f2904954c1 | wikidoc | TPD52L2 | TPD52L2
Tumor protein D54 is a protein that in humans is encoded by the TPD52L2 gene.
# Model organisms
Model organisms have been used in the study of TPD52L2 function. A conditional knockout mouse line, called Tpd52l2tm1a(KOMP)Wtsi was generated as part of the International Knockout Mouse Consortium program—a high-throughput mutagenesis project to generate and distribute animal models of disease to interested scientists.
Male and female animals underwent a standardized phenotypic screen to determine the effects of deletion.
Twenty two tests were carried out on mutant mice and one significant abnormality was observed: homozygous adult females displayed a decrease in body length by DEXA.
# Interactions
TPD52L2 has been shown to interact with TPD52L1 and TPD52. | TPD52L2
Tumor protein D54 is a protein that in humans is encoded by the TPD52L2 gene.[1][2]
# Model organisms
Model organisms have been used in the study of TPD52L2 function. A conditional knockout mouse line, called Tpd52l2tm1a(KOMP)Wtsi[7][8] was generated as part of the International Knockout Mouse Consortium program—a high-throughput mutagenesis project to generate and distribute animal models of disease to interested scientists.[9][10][11]
Male and female animals underwent a standardized phenotypic screen to determine the effects of deletion.[5][12]
Twenty two tests were carried out on mutant mice and one significant abnormality was observed: homozygous adult females displayed a decrease in body length by DEXA.[5]
# Interactions
TPD52L2 has been shown to interact with TPD52L1[1] and TPD52.[1] | https://www.wikidoc.org/index.php/TPD52L2 | |
d60875670f9782aee671caac7df0c8d0e5bce5f2 | wikidoc | TRAPPC2 | TRAPPC2
Trafficking protein particle complex subunit 2 (TRAPPC2) also known as MBP-1-interacting protein 2A (MIP-2A) is a protein that in humans is encoded by the TRAPPC2 gene. A processed pseudogene of this gene is located on chromosome 19, and other pseuodogenes of it are found on chromosome 8 and the Y chromosome. Two transcript variants encoding the same protein have been found for this gene.
# Function
Trafficking protein particle complex subunit 2 is thought to be part of a large multisubunit complex involved in the targeting and fusion of endoplasmic reticulum-to-Golgi transport vesicles with their acceptor compartment. In addition, the encoded protein can bind MBP1 and block its transcriptional repression capability.
# Genetic Location
The TRAPPC2 gene is located on the X-chromosome at position 22 between base-pairs 13,712,241 to 13,734,634.
# Clinical significance
Mutations in this gene are a cause of X-linked spondyloepiphyseal dysplasia tarda (SEDT).
# Interactions
TRAPPC2 has been shown to interact with Alpha-enolase and CLIC1. | TRAPPC2
Trafficking protein particle complex subunit 2 (TRAPPC2) also known as MBP-1-interacting protein 2A (MIP-2A) is a protein that in humans is encoded by the TRAPPC2 gene.[1][2] A processed pseudogene of this gene is located on chromosome 19, and other pseuodogenes of it are found on chromosome 8 and the Y chromosome. Two transcript variants encoding the same protein have been found for this gene.[2]
# Function
Trafficking protein particle complex subunit 2 is thought to be part of a large multisubunit complex involved in the targeting and fusion of endoplasmic reticulum-to-Golgi transport vesicles with their acceptor compartment. In addition, the encoded protein can bind MBP1 and block its transcriptional repression capability.[2]
# Genetic Location
The TRAPPC2 gene is located on the X-chromosome at position 22 between base-pairs 13,712,241 to 13,734,634.[3]
# Clinical significance
Mutations in this gene are a cause of X-linked spondyloepiphyseal dysplasia tarda (SEDT).[2]
# Interactions
TRAPPC2 has been shown to interact with Alpha-enolase[4] and CLIC1.[5] | https://www.wikidoc.org/index.php/TRAPPC2 | |
dcb34c48f5f39ee023810d5fadbb42d1d518e5f1 | wikidoc | TRPC4AP | TRPC4AP
Trpc4-associated protein is a protein that in humans is encoded by the TRPC4AP gene.
# Model organisms
Model organisms have been used in the study of TRPC4AP function. A conditional knockout mouse line, called Trpc4aptm1a(KOMP)Wtsi was generated as part of the International Knockout Mouse Consortium program — a high-throughput mutagenesis project to generate and distribute animal models of disease to interested scientists.
Male and female animals underwent a standardized phenotypic screen to determine the effects of deletion. Twenty five tests were carried out on mutant mice and three significant abnormalities were observed. Few homozygous mutant embryos were identified during gestation, and thus fewer than expected survived until weaning. The remaining tests were carried out on heterozygous mutant adult mice; females had an abnormal anagen phase of the hair cycle.
# Interactions
TRPC4AP has been shown to interact with TNFRSF1A. | TRPC4AP
Trpc4-associated protein is a protein that in humans is encoded by the TRPC4AP gene.
# Model organisms
Model organisms have been used in the study of TRPC4AP function. A conditional knockout mouse line, called Trpc4aptm1a(KOMP)Wtsi[6][7] was generated as part of the International Knockout Mouse Consortium program — a high-throughput mutagenesis project to generate and distribute animal models of disease to interested scientists.[8][9][10]
Male and female animals underwent a standardized phenotypic screen to determine the effects of deletion.[4][11] Twenty five tests were carried out on mutant mice and three significant abnormalities were observed.[4] Few homozygous mutant embryos were identified during gestation, and thus fewer than expected survived until weaning. The remaining tests were carried out on heterozygous mutant adult mice; females had an abnormal anagen phase of the hair cycle.[4]
# Interactions
TRPC4AP has been shown to interact with TNFRSF1A.[12][clarification needed] | https://www.wikidoc.org/index.php/TRPC4AP | |
111757d41db946184abb3f2ff54005a49ba876f7 | wikidoc | TSC22D1 | TSC22D1
TSC22 domain family protein 1 is a protein that in humans is encoded by the TSC22D1 gene.
TSC22 encodes a transcription factor and belongs to the large family of early response genes.
TSC22D1 forms homodimers via its conserved leucine zipper domain and heterodimerizes with TSC22D4. TSC22D1 has transcriptional repressor activity. | TSC22D1
TSC22 domain family protein 1 is a protein that in humans is encoded by the TSC22D1 gene.[1][2]
TSC22 encodes a transcription factor and belongs to the large family of early response genes.[3]
TSC22D1 forms homodimers via its conserved leucine zipper domain and heterodimerizes with TSC22D4. TSC22D1 has transcriptional repressor activity.[4] | https://www.wikidoc.org/index.php/TSC22D1 | |
b80a91ee9347d5721a9b2e42176fc00d5d1f86d3 | wikidoc | TSC22D3 | TSC22D3
TSC22 domain family protein 3 is a protein that in humans is encoded by the TSC22D3 gene.
# Function
The protein encoded by this gene shares significant sequence identity with the murine TSC-22 and Drosophila shs, both of which are leucine zipper proteins, that function as transcriptional regulators. GILZ shows ubiquitous expression across tissues, including thymus, spleen, lung, fat, liver, kidney, heart, and skeletal muscle. The expression of this gene is stimulated by glucocorticoids and interleukin 10, and it appears to play a key role in the anti-inflammatory and immunosuppressive effects of this steroid and chemokine. Transcript variants encoding different isoforms have been identified for this gene.
# Interactions
TSC22D3 has been shown to interact with C-Raf, NFKB2 and NFKB1. | TSC22D3
TSC22 domain family protein 3 is a protein that in humans is encoded by the TSC22D3 gene.[1][2]
# Function
The protein encoded by this gene shares significant sequence identity with the murine TSC-22 and Drosophila shs, both of which are leucine zipper proteins, that function as transcriptional regulators. GILZ shows ubiquitous expression across tissues, including thymus, spleen, lung, fat, liver, kidney, heart, and skeletal muscle.[3][4] The expression of this gene is stimulated by glucocorticoids and interleukin 10, and it appears to play a key role in the anti-inflammatory and immunosuppressive effects of this steroid and chemokine. Transcript variants encoding different isoforms have been identified for this gene.[2]
# Interactions
TSC22D3 has been shown to interact with C-Raf,[5] NFKB2[6] and NFKB1.[6] | https://www.wikidoc.org/index.php/TSC22D3 | |
ac5dc18a629d25727bcd92d15951228fda6a5492 | wikidoc | TSPAN32 | TSPAN32
Tetraspanin-32 is a protein that in humans is encoded by the TSPAN32 gene.
# Function
This gene is described as a member of the tetraspanin superfamily whose expression is confined to hematopoietic tissues.
# Clinical significance
This gene is one of several tumor-suppressing subtransferable fragments located in the imprinted gene domain of 11p15.5, an important tumor suppressor gene region. Alterations in this region have been associated with the Beckwith-Wiedemann syndrome, Wilms tumor, rhabdomyosarcoma, adrenocortical carcinoma, and lung, ovarian, and breast cancer. This gene is located among several imprinted genes; however, this gene, as well as the tumor-suppressing subchromosomal transferable fragment 4 (TSSC4), escapes imprinting. This gene may play a role in malignancies and disease that involve this region as well as hematopoietic cell function. | TSPAN32
Tetraspanin-32 is a protein that in humans is encoded by the TSPAN32 gene.[1][2][3]
# Function
This gene is described as a member of the tetraspanin superfamily whose expression is confined to hematopoietic tissues.[3]
# Clinical significance
This gene is one of several tumor-suppressing subtransferable fragments located in the imprinted gene domain of 11p15.5, an important tumor suppressor gene region. Alterations in this region have been associated with the Beckwith-Wiedemann syndrome, Wilms tumor, rhabdomyosarcoma, adrenocortical carcinoma, and lung, ovarian, and breast cancer. This gene is located among several imprinted genes; however, this gene, as well as the tumor-suppressing subchromosomal transferable fragment 4 (TSSC4), escapes imprinting. This gene may play a role in malignancies and disease that involve this region as well as hematopoietic cell function.[3] | https://www.wikidoc.org/index.php/TSPAN32 | |
d4612bbeb140b5e7c5ce540c8db603c56bcd3c0d | wikidoc | Tapasin | Tapasin
TAP-associated glycoprotein also known as tapasin or TAPBP is a protein that in humans is encoded by the TAPBP gene.
# Function
This gene encodes a transmembrane glycoprotein that mediates interaction between newly assembled major histocompatibility complex (MHC) class I molecules and the transporter associated with antigen processing (TAP), which is required for the transport of antigenic peptides across the endoplasmic reticulum membrane. This interaction facilitates optimal peptide loading on the MHC class I molecule. Up to four complexes of MHC class I and tapasin may be bound to a single TAP molecule. Tapasin contains a C-terminal double-lysine motif (KKKAE) known to maintain membrane proteins in the endoplasmic reticulum. In humans, the tapasin gene lies within the major histocompatibility complex on chromosome 6. Alternative splicing results in three transcript variants encoding different isoforms.
Tapasin is a MHC class I antigen-processing molecule present in the lumen of the endoplasmic reticulum. It plays an important role in the maturation of MHC class I molecules in the ER lumen. Tapasin is one component of the peptide-loading complex, and can be found associated with MHC class I molecules after the MHC class I heavy chain has associated with Beta2 microglobulin. The peptide-loading complex consists of TAP, tapasin, MHC class I, calreticulin, and ERp57. Tapasin recruits MHC class I molecules to the TAP peptide transporter, and also enhances loading of MHC class I with high-affinity peptides. Following loading of MHC class I with a high-affinity ligand, the interaction between tapasin and MHC class I disappears.
# Interactions
Tapasin has been shown to interact with:
- HLA-A, and
- TAP1 | Tapasin
TAP-associated glycoprotein also known as tapasin or TAPBP is a protein[1][2] that in humans is encoded by the TAPBP gene.[3]
# Function
This gene encodes a transmembrane glycoprotein that mediates interaction between newly assembled major histocompatibility complex (MHC) class I molecules and the transporter associated with antigen processing (TAP), which is required for the transport of antigenic peptides across the endoplasmic reticulum membrane. This interaction facilitates optimal peptide loading on the MHC class I molecule. Up to four complexes of MHC class I and tapasin may be bound to a single TAP molecule. Tapasin contains a C-terminal double-lysine motif (KKKAE) known to maintain membrane proteins in the endoplasmic reticulum. In humans, the tapasin gene lies within the major histocompatibility complex on chromosome 6. Alternative splicing results in three transcript variants encoding different isoforms.[3]
Tapasin is a MHC class I antigen-processing molecule present in the lumen of the endoplasmic reticulum. It plays an important role in the maturation of MHC class I molecules in the ER lumen. Tapasin is one component of the peptide-loading complex, and can be found associated with MHC class I molecules after the MHC class I heavy chain has associated with Beta2 microglobulin. The peptide-loading complex consists of TAP, tapasin, MHC class I, calreticulin, and ERp57. Tapasin recruits MHC class I molecules to the TAP peptide transporter, and also enhances loading of MHC class I with high-affinity peptides. Following loading of MHC class I with a high-affinity ligand, the interaction between tapasin and MHC class I disappears.[4]
# Interactions
Tapasin has been shown to interact with:
- HLA-A,[5] and
- TAP1[5][6] | https://www.wikidoc.org/index.php/Tapasin | |
a2f838766a3de9638a068a22502b81bdc315df8c | wikidoc | Tapioca | Tapioca
# Overview
Tapioca (Template:IPA-pt) is a starch extracted from cassava root (Manihot esculenta). This species is native to the North Region of Brazil, but spread throughout the South American continent. The plant was carried by Portuguese and Spanish explorers to most of the West Indies, and continents of Africa and Asia, including the Philippines and Taiwan. It is now cultivated worldwide.
A staple food in many world regions, tapioca is used as a thickening agent in various foods.
# Etymology and origin
In Brazil, cassava is called mandioca or aipim while its starch is called tapioca, a word derived from the word tipi'óka, its name in the Tupí language spoken by natives when the Portuguese first arrived in the Northeast Region of Brazil. This Tupí word refers to the process by which the cassava starch is made edible.
# Production
Tapioca is one of the purest forms of starch food, and the production varies from region to region.
The cassava plant has either red or green branches with blue spindles on them. The root of the green-branched variant requires treatment to remove linamarin, a cyanogenic glycoside occurring naturally in the plant, which otherwise may be converted into cyanide. Konzo (also called mantakassa) is a paralytic disease associated with several weeks of almost exclusive consumption of insufficiently processed bitter cassava.
In the North and Northeast of Brazil, traditional community based production of tapioca is a by-product of manioc flour production from cassava roots. In this process, the manioc (after treatment to remove toxicity) is ground to a pulp with a small hand- or diesel-powered mill. This masa is then squeezed to dry it out. The wet masa is placed in a long woven tube called a tipiti. The top of the tube is secured while a large branch or lever is inserted into a loop at the bottom and used to stretch the entire implement vertically, squeezing a starch-rich liquid out through the weave and ends. This liquid is collected and the water allowed to evaporate, leaving behind a fine-grained tapioca powder similar in appearance to corn starch.
Commercially, the starch is processed into several forms: hot soluble powder, meal, pre-cooked fine/coarse flakes, rectangular sticks, and spherical "pearls". Pearls are the most widely available shape; sizes range from about 1 mm to 8 mm in diameter, with 2–3 mm being the most common.
Flakes, sticks, and pearls must be soaked well before cooking, in order to rehydrate, absorbing water up to twice their volume. After rehydration, tapioca products become leathery and swollen. Processed tapioca is usually white, but sticks and pearls may be colored. Since old times, the most common color applied to tapioca has been brown, but recently pastel colors have been available. Tapioca pearls are generally opaque when raw, but become translucent when cooked in boiling water.
Brazil in South America, Thailand in Asia, and Nigeria in Africa are the world's largest producers of cassava. Currently, Thailand accounts for about 60% of worldwide exports.
# Uses
## Nutritional value
Tapioca predominantly consists of carbohydrates, with each cup containing 23.9 grams for a total of 105 calories; it is low in saturated fat, protein and sodium. It has no significant essential vitamins or dietary minerals. One serving of tapioca pudding contains no dietary fiber, a small amount of oleic acid, and no omega-3 or omega-6 fatty acids.
## Flatbreads
A casabe is a thin flatbread made from bitter cassava root without leavening. It was originally produced by the indigenous Arawak and Carib peoples because these roots were a common plant of the rain forests where they lived. In eastern Venezuela, many indigenous groups still make casabe. It is their chief bread-like staple. Indigenous communities, such as the Ye-Kuana, Kari-Ña, Yanomami, Guarao or Warao descended from the Caribe or Arawac nations, still make casabe.
To make casabe, the starchy root of bitter cassava is ground to a pulp, then squeezed to expel a milky, bitter liquid called yare. This carries the poisonous substances with it out of the pulp. Traditionally, this squeezing is done in a sebucan, an 8 to 12 foot (3.6576 m) long, tube-shaped, pressure strainer, woven in a characteristic helical pattern from palm leaves. The sebucan usually is hung from a tree branch or ceiling pole, and it has a closed bottom with a loop that is attached to a fixed stick or lever, which is used to stretch the sebucan. When the lever is pushed down, stretching the sebucan, the helical weaving pattern causes the strainer to squeeze the pulp inside. This is similar to the action of a Chinese finger trap. The pulp is spread in thin, round cakes about 2 feet (0.6096 m) in diameter on a budare to roast or toast.
Thin and crisp cakes of casabe are often broken apart and eaten like crackers. Like bread, casabe can be eaten alone or with other dishes. Thicker casabe usually are eaten slightly moistened. A sprinkle of a few drops of liquid is enough to transform a dry casabe into a very soft and smooth bread similar to the softest slice of a wheat bread loaf. Because of its capacity to absorb liquid immediately, casabe may cause someone to choke, but goes down quickly with a sip of liquid.
In Guyana, the casabe is called cassava bread. It is prepared with an instrument called a matape by the natives of the Rupununi Savanah and other areas of the country that have a high concentration of Amerinidians. In Jamaica, it is called bammy.
In Brazil, the cassava flatbread is called beiju or tapioca.
## Tapioca pearls
Tapioca pearls are also known as boba in some cultures. It is produced by passing the moist starch through a sieve under pressure. Pearl tapioca is a common ingredient in Asian desserts such as falooda, kolak, sago soup, and in sweet drinks such as bubble tea, fruit slush and taho, where they provide a chewy contrast to the sweetness and texture of the drink. Small pearls are preferred for use in puddings. In Brazil, those pearls are cooked with wine or other liquid to add flavor, and are called Sagu.
Large pearls are preferred for use in drinks. These large pearls most often are brown, not white (and traditionally are used in black or green tea drinks), but today are available in a wide variety of pastel colors. They are also available as an option in shave ice and hot drinks. In addition to their use in puddings and beverages, a recent innovation has been to cook tapioca pearls inside cakes.
## World War II
During World War II, due to the shortage of food in Southeast Asia, many refugees survived on tapioca. The cassava plant is easily propagated by stem-cutting, grows well in low-nutrient soils, and can be harvested every two months, although it takes ten months to grow to full maturity. The plant provided much needed carbohydrates and other nutrients during wartime.
## Biodegradable products
Tapioca root can be used to manufacture biodegradable bags developed from a tapioca resin of the plant as a viable plastic substitute. Not only is it biodegradable, but it can be composted, is renewable, reusable, recyclable and sustainable. Other tapioca resin products include reusable gloves, capes and aprons.
## Laundry
Tapioca starch, used commonly for starching shirts and garments before ironing, may be sold in bottles of natural gum starch to be dissolved in water or in spray cans.
# Regional applications
## South America
### Brazil
In Brazilian cuisine, tapioca is used for different types of meals. In beiju (or biju), the tapioca is moistened, strained through a sieve to become a coarse flour, then sprinkled onto a hot griddle or pan, where the heat makes the starchy grains fuse into a flatbread which resembles a grainy pancake. Then it may be buttered and eaten as a toast (its most common use as a breakfast dish), or it may be filled or topped with either salgados (salty pastry recipes) or doces (sweet pastry recipes), which define the kind of meal the tapioca is used for: breakfast/dinner, or dessert. Choices for fillings range from butter, cheese, ham, bacon, various kinds of meat, chocolate, fruits such as ground coconut, condensed milk, chocolate with sliced pieces of banana or strawberry, among others. This kind of tapioca dish is usually served warm.
A regional dessert called sagu is also made in Southern Brazil from tapioca pearls cooked with cinnamon and cloves in red wine. The cassava root is known by different names throughout the country: mandioca in the North, Central-West and in São Paulo; tapioca or macaxeira in the Northeast; aipim in the Southeast (especially in Rio de Janeiro).
The fine-grained tapioca starch is called polvilho, and it is classified as either "sweet" or "sour". Sour polvilho is commonly used in dishes such as ] or "cheese bread", in which the starch is mixed with a hard cheese, usually matured Minas cheese (could be substituted by Parmesan cheese), eggs and butter and baked in the oven. The final result is an aromatic, chewy and elastic kind of bread that is ubiquitous across the country. Sour cassava flour is mixed into mashed beans to make the dish tutu de feijão.
### Other locations
In Colombia and Venezuela, arepas may be made with tapioca flour rather than cornmeal. Tapioca arepas probably predate cornmeal arepas; among traditional cultures of the Caribbean the name for them is casabe. Throughout both Spanish and Portuguese South America, the tapioca, or yuca, starch is used to make regional variations of the baked cheese bun, known locally as pandebono, pan de yuca, pão de queijo, chipá, or cuñapé, among other names.
The whole unprocessed cassava root also has a number of culinary uses throughout South America.
## North America
While frequently associated with tapioca pudding, a dessert in the United States, tapioca is also used in other courses. People on gluten-free diets can eat bread made with tapioca flour (although these individuals have to be careful, as some tapioca flour has wheat added to it).
## West Indies
Tapioca was used by the first inhabitants of the West Indies as a staple food from which they made main dishes, such as pepper pot, and also used it to make alcohol. They used it for teeth cleaning, and it is still used as a base locally for toothpaste. In the 21st century, it is still a very popular food in the islands, used as a provision cooked with meats or fish, and in desserts such as cassava pone.
## Asia
In various Asian countries, including Indonesia, China, Thailand, Vietnam, India, Pakistan, Bangladesh, Myanmar, Philippines, Malaysia, and Taiwan, tapioca pearls are widely used and are known as sagudana, sabudana or shabudana (pearl sago) or "sabba akki" (ಕನ್ನಡ: ಸಬ್ಬಕ್ಕಿ in Kannada). It has religious importance in certain communities and used as a staple food for fasting. The pearls (sagudana or shabudana/sabudana) are used to make snacks. Tapioca pearls are essential ingredients for Taiwanese Bubble Tea.
### Southeast Asia
In Southeast Asia, the cassava root is commonly cut into slices, wedges or strips, fried, and served as a snack, similar to potato chips, wedges or french fries. Another method is to boil large blocks until soft, and serve them with grated coconut as a dessert, either slightly salted or sweetened, usually with palm sugar syrup. In Thailand this dish is called Mansampalang (มันสำปะหลัง).
Tapai is made by fermenting large blocks with a yeast-like bacteria culture to produce a sweet and slightly alcoholic dessert. Further fermentation releases more liquids and alcohol producing Tuak, a sour alcoholic beverage.
A variation of the chips popular amongst the Malays is kerepek pedas, where the crisps are coated with a hot, sweet and tangy chili and onion paste, or sambal, usually with fried anchovies and peanuts added.
Krupuk, or crackers, is a major use of tapioca starch in Indonesia.
Commercially prepared tapioca has many uses. Tapioca powder is commonly used as a thickener for soups and other liquid foods. It is also used as a binder in pharmaceutical tablets and natural paints. The flour is used to make tender breads, cakes, biscuits, cookies, and other delicacies (see also Maida flour). Tapioca flakes are used to thicken the filling of pies made with fruits having a high water content.
A typical recipe for tapioca jelly can be made by washing 2 tablespoonfuls of tapioca, pouring a pint of water over it, and soaking for three hours. The mixture is placed over low heat and simmered until quite clear. If too thick, a little boiling water can be added. It can be sweetened with white sugar, flavored with coconut milk or a little wine, and eaten alone or with cream.
### Sri Lanka
It is known as "Mangnokka" in Sri Lanka and Mauritius, as well as by its Sinhalese and Tamil names. It is generally eaten boiled with a chili onion mixture called "Lunu Miris Sambol" (type of a salsa) or coconut sambol. At the same time, it is very popular to have tapioca pearls prepared as a delicacy. At one time, tapioca pearls were used to starch clothes by boiling tapioca pearls with the clothes.
### Bangladesh and Bengal province (India)
During religious fasts, sabudana is a popular alternative to rice-based foods. Consumed with curd or milk or prepared as a Khichdi, sago is particularly popular choice during the fasts of 'Ramadan','Ombubachi', Nilshosthi and Ekadoshi. Traditionally, tapioca pearls are used as the food for children, elderly and ill people, mixed with milk or water. Faluda, a popular food, is also prepared with curd, ice and other ingredient during summer.
### India
Tapioca is a common ingredient of some Indian dishes and the most common form that is added into dishes is in the form of Tapioca Pearls. Local words for Tapioca roots in India include: Odia Sagudana, Malayalam kappa or maraccīni, Tamil maravaḷḷikilanku, Kannada sabakki(ಸಾಬಕ್ಕಿ)', Hindi (साबूदाना) and saggu biyyam (సగ్గు బియ్యం) Telugu language. which used to prepare sabbakki payasam in indian traditional foods
Cassava, often referred to as tapioca from its word in Portuguese, is called Kappa (കപ്പ) Kizhangu or
(in northern Kerala) or Maracheeni or Cheeni or Kolli or Mathock (മത്തോക്ക്), Poola (പൂള) in Malayalam.
Tapioca is widely consumed in the Indian state of Kerala, usually as breakfast or in the evening. It is boiled (after skinning and cutting it into large cakes of about long or into small cubes) in water till properly cooked, and the water is drained off. Once cooked, it can be mixed with grated coconut, chili, salt, turmeric etc., then steamed and mashed into a dry pudding. This can be garnished in oil with mustard, onion, curry leaves etc. if desired. Tapioca cakes (Chendan Kappa) are often eaten with simple chili sauce (a paste of Green/Red Chili + Shallot + small red Onion + Garlic + Salt + Oil).
Mashed Tapioca is paired with Meat / Fish curry. Tapioca with fish curry (especially sardines) is a delicacy in Kerala. Mashed Tapioca with Chutta Unakka Mathi (dry salted sardine directly cooked on charcoal) and Green Chili is another popular combination. Kappa Biriyani is yet another Tapioca dish.
Tapioca can be stored for longer periods by parboiling and drying it, after skinning and slicing it into 0.5 cm thick pieces. This is called Unakka Kappa or Vaattu Kappa (dried tapioca). Unakka Kappa pudding is widely consumed in Kerala. Tapioca Chips, thinly sliced tapioca wafers, similar to potato chips, are also popular.
In Tamil, the roots of tapioca are called Maravalli Kilangu, and are used to prepare chips. Tapioca chips are also prepared in parts of South India.
Tapioca pearls are referred to as "Javvarisi" in Tamil. Most of the delicacies are cooked from this form of tapioca because it is relatively easier to handle than the raw root by itself. In Tamil Nadu, tapioca is cultivated more in several districts, providing steady income to farmers. Tapioca can be consumed raw (after removing the skins/outer cover) or boiled for various dishes or snacks.
In Nagaland and Mizoram in Northeast India, tapioca is eaten as a snack. It is usually boiled with a bit of salt in water after skinning it, or snacks are made by drying the tapioca after cutting it. It is then powdered into flour and turned into dough to either make a fired or baked biscuit. In their local dialect, they call it kuri aloo, meaning "wood potato". These chips are eaten by all groups of society as a delicacy. The skin of the tapioca, which is not edible for humans, is kept aside to prepare a food for domesticated pigs.
In Assam, sabudana is also used as substitute diet against boiled rice (bhaat) for the sick elderly or infirm for easy digestion and strength.
## Africa
Tapioca is eaten in the regions of Nigeria and Ghana as the everyday-man's meal, and is usually taken for breakfast. The various tribes use it in multiple dishes.
Cassava is a staple food in West Africa where it is widely eaten. In Nigeria cassava is grated and dry roasted into 'gari', this is eaten by adding water, sugar and or peanuts accompanied by meat or smoked fish. Gari is also made into 'eba' by adding hot water, this is eaten with stew or soup. The 'Ijebu' tribe of Nigeria make a cold water variant of eba by pounding the mixture with their fist until it becomes homogenous, this is called 'feshelu'. The Egbas of Abeokuta Ogun State peel, dry and grind cassava into a powder called 'elubo', this is made into 'amala paki', this is eaten with jute leaf stew called 'ewedu'.
In Lagos cassava is processed into tapioca which is cooked in coconut milk and sugar, this can be eaten as a breakfast meal or as a dessert at parties or dinner. This is called 'mengau'.
The Igbos of Eastern Nigeria add palm oil to grated cassava during roasting, this is called 'yellow gari'.
The tribes in Niger Delta extract starch from cassava, this is cooked into a glutinous meal called 'starch', it is eaten with 'pepper soup'.
In Ghana, cassava is peeled, boiled until tender, then pounded in a large wooden mortar and pestle until it becomes homogenous, this is called 'fufu', it is eaten with soup.
## Europe
Tapioca is not as widely used in Europe, but several countries make use of tapioca. In Belgium, small white tapioca pearls are added to clear soups. Tapioca balls are used in French desserts, such as parfaits. The savory snack in the United Kingdom, Skips, are made of tapioca and flavored like prawn cocktail, as well as other flavors.
Tapioca is also widely available in its dried forms and is used to make tapioca pudding. | Tapioca
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]
# Overview
Tapioca (Template:IPA-pt) is a starch extracted from cassava root (Manihot esculenta). This species is native to the North Region of Brazil, but spread throughout the South American continent. The plant was carried by Portuguese and Spanish explorers to most of the West Indies, and continents of Africa and Asia, including the Philippines and Taiwan. It is now cultivated worldwide.
A staple food in many world regions, tapioca is used as a thickening agent in various foods.
# Etymology and origin
In Brazil, cassava is called mandioca or aipim while its starch is called tapioca, a word derived from the word tipi'óka, its name in the Tupí language spoken by natives when the Portuguese first arrived in the Northeast Region of Brazil.[1] This Tupí word refers to the process by which the cassava starch is made edible.
# Production
Tapioca is one of the purest forms of starch food, and the production varies from region to region.
The cassava plant has either red or green branches with blue spindles on them. The root of the green-branched variant requires treatment to remove linamarin, a cyanogenic glycoside occurring naturally in the plant, which otherwise may be converted into cyanide.[2] Konzo (also called mantakassa) is a paralytic disease associated with several weeks of almost exclusive consumption of insufficiently processed bitter cassava.
In the North and Northeast of Brazil, traditional community based production of tapioca is a by-product of manioc flour production from cassava roots. In this process, the manioc (after treatment to remove toxicity) is ground to a pulp with a small hand- or diesel-powered mill. This masa is then squeezed to dry it out. The wet masa is placed in a long woven tube called a tipiti. The top of the tube is secured while a large branch or lever is inserted into a loop at the bottom and used to stretch the entire implement vertically, squeezing a starch-rich liquid out through the weave and ends. This liquid is collected and the water allowed to evaporate, leaving behind a fine-grained tapioca powder similar in appearance to corn starch.
Commercially, the starch is processed into several forms: hot soluble powder, meal, pre-cooked fine/coarse flakes, rectangular sticks, and spherical "pearls".[3] Pearls are the most widely available shape; sizes range from about 1 mm to 8 mm in diameter, with 2–3 mm being the most common.
Flakes, sticks, and pearls must be soaked well before cooking, in order to rehydrate, absorbing water up to twice their volume. After rehydration, tapioca products become leathery and swollen. Processed tapioca is usually white, but sticks and pearls may be colored. Since old times, the most common color applied to tapioca has been brown, but recently pastel colors have been available. Tapioca pearls are generally opaque when raw, but become translucent when cooked in boiling water.
Brazil in South America, Thailand in Asia, and Nigeria in Africa are the world's largest producers of cassava. Currently, Thailand accounts for about 60% of worldwide exports.[4]
# Uses
## Nutritional value
Tapioca predominantly consists of carbohydrates, with each cup containing 23.9 grams for a total of 105 calories; it is low in saturated fat, protein and sodium.[5] It has no significant essential vitamins or dietary minerals.[5] One serving of tapioca pudding contains no dietary fiber, a small amount of oleic acid, and no omega-3 or omega-6 fatty acids.[5]
## Flatbreads
A casabe is a thin flatbread made from bitter cassava root without leavening. It was originally produced by the indigenous Arawak and Carib peoples because these roots were a common plant of the rain forests where they lived. In eastern Venezuela, many indigenous groups still make casabe. It is their chief bread-like staple. Indigenous communities, such as the Ye-Kuana, Kari-Ña, Yanomami, Guarao or Warao descended from the Caribe or Arawac nations, still make casabe.[6]
To make casabe, the starchy root of bitter cassava is ground to a pulp, then squeezed to expel a milky, bitter liquid called yare. This carries the poisonous substances with it out of the pulp. Traditionally, this squeezing is done in a sebucan, an 8 to 12 foot (3.6576 m) long, tube-shaped, pressure strainer, woven in a characteristic helical pattern from palm leaves. The sebucan usually is hung from a tree branch or ceiling pole, and it has a closed bottom with a loop that is attached to a fixed stick or lever, which is used to stretch the sebucan. When the lever is pushed down, stretching the sebucan, the helical weaving pattern causes the strainer to squeeze the pulp inside. This is similar to the action of a Chinese finger trap. The pulp is spread in thin, round cakes about 2 feet (0.6096 m) in diameter on a budare to roast or toast.
Thin and crisp cakes of casabe are often broken apart and eaten like crackers. Like bread, casabe can be eaten alone or with other dishes. Thicker casabe usually are eaten slightly moistened. A sprinkle of a few drops of liquid is enough to transform a dry casabe into a very soft and smooth bread similar to the softest slice of a wheat bread loaf. Because of its capacity to absorb liquid immediately, casabe may cause someone to choke, but goes down quickly with a sip of liquid.
In Guyana, the casabe is called cassava bread. It is prepared with an instrument called a matape by the natives of the Rupununi Savanah and other areas of the country that have a high concentration of Amerinidians. In Jamaica, it is called bammy.
In Brazil, the cassava flatbread is called beiju or tapioca.
## Tapioca pearls
Tapioca pearls are also known as boba in some cultures. It is produced by passing the moist starch through a sieve under pressure. Pearl tapioca is a common ingredient in Asian desserts such as falooda, kolak, sago soup, and in sweet drinks such as bubble tea, fruit slush and taho, where they provide a chewy contrast to the sweetness and texture of the drink. Small pearls are preferred for use in puddings. In Brazil, those pearls are cooked with wine or other liquid to add flavor, and are called Sagu.
Large pearls are preferred for use in drinks. These large pearls most often are brown, not white (and traditionally are used in black or green tea drinks), but today are available in a wide variety of pastel colors. They are also available as an option in shave ice and hot drinks. In addition to their use in puddings and beverages, a recent innovation has been to cook tapioca pearls inside cakes.[7]
## World War II
During World War II, due to the shortage of food in Southeast Asia, many refugees survived on tapioca. The cassava plant is easily propagated by stem-cutting, grows well in low-nutrient soils, and can be harvested every two months, although it takes ten months to grow to full maturity. The plant provided much needed carbohydrates and other nutrients during wartime.[8]
## Biodegradable products
Tapioca root can be used to manufacture biodegradable bags developed from a tapioca resin of the plant as a viable plastic substitute. Not only is it biodegradable, but it can be composted, is renewable, reusable, recyclable and sustainable. Other tapioca resin products include reusable gloves, capes and aprons.[citation needed]
## Laundry
Tapioca starch, used commonly for starching shirts and garments before ironing, may be sold in bottles of natural gum starch to be dissolved in water or in spray cans.
# Regional applications
## South America
### Brazil
In Brazilian cuisine, tapioca is used for different types of meals. In beiju (or biju), the tapioca is moistened, strained through a sieve to become a coarse flour, then sprinkled onto a hot griddle or pan, where the heat makes the starchy grains fuse into a flatbread which resembles a grainy pancake. Then it may be buttered and eaten as a toast (its most common use as a breakfast dish), or it may be filled or topped with either salgados (salty pastry recipes) or doces (sweet pastry recipes), which define the kind of meal the tapioca is used for: breakfast/dinner, or dessert. Choices for fillings range from butter, cheese, ham, bacon, various kinds of meat, chocolate, fruits such as ground coconut, condensed milk, chocolate with sliced pieces of banana or strawberry, among others. This kind of tapioca dish is usually served warm.
A regional dessert called sagu is also made in Southern Brazil from tapioca pearls cooked with cinnamon and cloves in red wine. The cassava root is known by different names throughout the country: mandioca in the North, Central-West and in São Paulo; tapioca or macaxeira in the Northeast; aipim in the Southeast (especially in Rio de Janeiro).
The fine-grained tapioca starch is called polvilho, and it is classified as either "sweet" or "sour". Sour polvilho is commonly used in dishes such as [[pão de queijo]] or "cheese bread", in which the starch is mixed with a hard cheese, usually matured Minas cheese (could be substituted by Parmesan cheese), eggs and butter and baked in the oven. The final result is an aromatic, chewy and elastic kind of bread that is ubiquitous across the country. Sour cassava flour is mixed into mashed beans to make the dish tutu de feijão.
### Other locations
In Colombia and Venezuela, arepas may be made with tapioca flour rather than cornmeal. Tapioca arepas probably predate cornmeal arepas[citation needed]; among traditional cultures of the Caribbean the name for them is casabe. Throughout both Spanish and Portuguese South America, the tapioca, or yuca, starch is used to make regional variations of the baked cheese bun, known locally as pandebono, pan de yuca, pão de queijo, chipá, or cuñapé, among other names.
The whole unprocessed cassava root also has a number of culinary uses throughout South America.
## North America
While frequently associated with tapioca pudding, a dessert in the United States, tapioca is also used in other courses.[9] People on gluten-free diets can eat bread made with tapioca flour (although these individuals have to be careful, as some tapioca flour has wheat added to it).
## West Indies
Tapioca was used by the first inhabitants of the West Indies as a staple food from which they made main dishes, such as pepper pot, and also used it to make alcohol. They used it for teeth cleaning, and it is still used as a base locally for toothpaste. In the 21st century, it is still a very popular food in the islands, used as a provision cooked with meats or fish, and in desserts such as cassava pone.[citation needed]
## Asia
In various Asian countries, including Indonesia, China, Thailand, Vietnam, India, Pakistan, Bangladesh, Myanmar, Philippines, Malaysia, and Taiwan, tapioca pearls are widely used and are known as sagudana, sabudana or shabudana (pearl sago) or "sabba akki" (ಕನ್ನಡ: ಸಬ್ಬಕ್ಕಿ in Kannada). It has religious importance in certain communities and used as a staple food for fasting. The pearls (sagudana or shabudana/sabudana) are used to make snacks. Tapioca pearls are essential ingredients for Taiwanese Bubble Tea.
### Southeast Asia
In Southeast Asia, the cassava root is commonly cut into slices, wedges or strips, fried, and served as a snack, similar to potato chips, wedges or french fries. Another method is to boil large blocks until soft, and serve them with grated coconut as a dessert, either slightly salted or sweetened, usually with palm sugar syrup. In Thailand this dish is called Mansampalang (มันสำปะหลัง).
Tapai is made by fermenting large blocks with a yeast-like bacteria culture to produce a sweet and slightly alcoholic dessert. Further fermentation releases more liquids and alcohol producing Tuak, a sour alcoholic beverage.
A variation of the chips popular amongst the Malays is kerepek pedas, where the crisps are coated with a hot, sweet and tangy chili and onion paste, or sambal, usually with fried anchovies and peanuts added.
Krupuk, or crackers, is a major use of tapioca starch in Indonesia.
Commercially prepared tapioca has many uses. Tapioca powder is commonly used as a thickener for soups and other liquid foods. It is also used as a binder in pharmaceutical tablets and natural paints. The flour is used to make tender breads, cakes, biscuits, cookies, and other delicacies (see also Maida flour). Tapioca flakes are used to thicken the filling of pies made with fruits having a high water content.
A typical recipe for tapioca jelly can be made by washing 2 tablespoonfuls of tapioca, pouring a pint of water over it, and soaking for three hours. The mixture is placed over low heat and simmered until quite clear. If too thick, a little boiling water can be added. It can be sweetened with white sugar, flavored with coconut milk or a little wine, and eaten alone or with cream.
### Sri Lanka
It is known as "Mangnokka" in Sri Lanka and Mauritius, as well as by its Sinhalese and Tamil names. It is generally eaten boiled with a chili onion mixture called "Lunu Miris Sambol" (type of a salsa) or coconut sambol. At the same time, it is very popular to have tapioca pearls prepared as a delicacy. At one time, tapioca pearls were used to starch clothes by boiling tapioca pearls with the clothes.
### Bangladesh and Bengal province (India)
During religious fasts, sabudana is a popular alternative to rice-based foods. Consumed with curd or milk or prepared as a Khichdi, sago is particularly popular choice during the fasts of 'Ramadan','Ombubachi', Nilshosthi and Ekadoshi. Traditionally, tapioca pearls are used as the food for children, elderly and ill people, mixed with milk or water. Faluda, a popular food, is also prepared with curd, ice and other ingredient during summer.
### India
Tapioca is a common ingredient of some Indian dishes and the most common form that is added into dishes is in the form of Tapioca Pearls. Local words for Tapioca roots in India include: Odia Sagudana, Malayalam kappa or maraccīni, Tamil maravaḷḷikilanku, Kannada sabakki(ಸಾಬಕ್ಕಿ)', Hindi (साबूदाना) and saggu biyyam (సగ్గు బియ్యం) Telugu language. which used to prepare sabbakki payasam in indian traditional foods
Cassava, often referred to as tapioca from its word in Portuguese, is called Kappa (കപ്പ) Kizhangu or
(in northern Kerala) or Maracheeni or Cheeni or Kolli or Mathock (മത്തോക്ക്), Poola (പൂള) in Malayalam.
Tapioca is widely consumed in the Indian state of Kerala, usually as breakfast or in the evening. It is boiled (after skinning and cutting it into large cakes of about long or into small cubes) in water till properly cooked, and the water is drained off. Once cooked, it can be mixed with grated coconut, chili, salt, turmeric etc., then steamed and mashed into a dry pudding. This can be garnished in oil with mustard, onion, curry leaves etc. if desired. Tapioca cakes (Chendan Kappa) are often eaten with simple chili sauce (a paste of Green/Red Chili + Shallot + small red Onion + Garlic + Salt + Oil).
Mashed Tapioca is paired with Meat / Fish curry. Tapioca with fish curry (especially sardines) is a delicacy in Kerala. Mashed Tapioca with Chutta Unakka Mathi (dry salted sardine directly cooked on charcoal) and Green Chili is another popular combination. Kappa Biriyani is yet another Tapioca dish.
Tapioca can be stored for longer periods by parboiling and drying it, after skinning and slicing it into 0.5 cm thick pieces. This is called Unakka Kappa or Vaattu Kappa (dried tapioca). Unakka Kappa pudding is widely consumed in Kerala. Tapioca Chips, thinly sliced tapioca wafers, similar to potato chips, are also popular.
In Tamil, the roots of tapioca are called Maravalli Kilangu, and are used to prepare chips. Tapioca chips are also prepared in parts of South India.
Tapioca pearls are referred to as "Javvarisi" in Tamil. Most of the delicacies are cooked from this form of tapioca because it is relatively easier to handle than the raw root by itself. In Tamil Nadu, tapioca is cultivated more in several districts, providing steady income to farmers. Tapioca can be consumed raw (after removing the skins/outer cover) or boiled for various dishes or snacks.
In Nagaland and Mizoram in Northeast India, tapioca is eaten as a snack. It is usually boiled with a bit of salt in water after skinning it, or snacks are made by drying the tapioca after cutting it. It is then powdered into flour and turned into dough to either make a fired or baked biscuit. In their local dialect, they call it kuri aloo, meaning "wood potato". These chips are eaten by all groups of society as a delicacy. The skin of the tapioca, which is not edible for humans, is kept aside to prepare a food for domesticated pigs.
In Assam, sabudana is also used as substitute diet against boiled rice (bhaat) for the sick elderly or infirm for easy digestion and strength.
## Africa
Tapioca is eaten in the regions of Nigeria and Ghana as the everyday-man's meal, and is usually taken for breakfast. The various tribes use it in multiple dishes.[citation needed]
Cassava is a staple food in West Africa where it is widely eaten. In Nigeria cassava is grated and dry roasted into 'gari', this is eaten by adding water, sugar and or peanuts accompanied by meat or smoked fish. Gari is also made into 'eba' by adding hot water, this is eaten with stew or soup. The 'Ijebu' tribe of Nigeria make a cold water variant of eba by pounding the mixture with their fist until it becomes homogenous, this is called 'feshelu'. The Egbas of Abeokuta Ogun State peel, dry and grind cassava into a powder called 'elubo', this is made into 'amala paki', this is eaten with jute leaf stew called 'ewedu'.
In Lagos cassava is processed into tapioca which is cooked in coconut milk and sugar, this can be eaten as a breakfast meal or as a dessert at parties or dinner. This is called 'mengau'.
The Igbos of Eastern Nigeria add palm oil to grated cassava during roasting, this is called 'yellow gari'.
The tribes in Niger Delta extract starch from cassava, this is cooked into a glutinous meal called 'starch', it is eaten with 'pepper soup'.
In Ghana, cassava is peeled, boiled until tender, then pounded in a large wooden mortar and pestle until it becomes homogenous, this is called 'fufu', it is eaten with soup.
## Europe
Tapioca is not as widely used in Europe, but several countries make use of tapioca. In Belgium, small white tapioca pearls are added to clear soups. Tapioca balls are used in French desserts, such as parfaits. The savory snack in the United Kingdom, Skips, are made of tapioca and flavored like prawn cocktail, as well as other flavors.
Tapioca is also widely available in its dried forms and is used to make tapioca pudding. | https://www.wikidoc.org/index.php/Tapioca | |
cc324299f8f41d78e77b236a11419b8534915d03 | wikidoc | Tarnish | Tarnish
Tarnish is a layer of corrosion that develops over copper,
brass, silver, aluminum as well as a degree of semi-reactive metals as they undergo oxidation. It is analogous to rust, but with a slower rate of occurrence. It is mainly caused by chemicals in the air such as sulphur. It appears as a grey or black film over the metal.
# Prevention
In objects which are primarily for display rather than use, the tarnishing process can be prevented in the long term by tinning, a process by which the reactive substance is coated in a non-reactive substance, such as tin or wax, and thus protected from oxygen.
For more frequently used items such as silverware, tarnish is easily prevented by constant use and washing with a mild dish soap.
# Removal
"This kitchen version of electrostripping is safe and easy. It's especially useful for removing tarnish from flatware and holloware. In a pot lined with aluminum foil, mix a diluted solution of equal parts of baking soda salt, and liquid soap. A quarter cup of each to a gallon of water is a typical mixture. Set the sterling in the pot; bring the mix to a simmer and allow it to stand for 10-20 minutes as the oxides are transferred to the aluminum, which you'll see is darkened. Throw that away and wash the silver before using it".
Another way to treat tarnish is to put a drop of water and some fluoride toothpaste on a tissue and rub it on the silver (or metal, but silver is the most common to be targeted by tarnish). | Tarnish
Tarnish is a layer of corrosion that develops over copper,
brass, silver, aluminum as well as a degree of semi-reactive metals as they undergo oxidation. It is analogous to rust, but with a slower rate of occurrence. It is mainly caused by chemicals in the air such as sulphur. It appears as a grey or black film over the metal.
# Prevention
In objects which are primarily for display rather than use, the tarnishing process can be prevented in the long term by tinning, a process by which the reactive substance is coated in a non-reactive substance, such as tin or wax, and thus protected from oxygen.[citation needed]
For more frequently used items such as silverware, tarnish is easily prevented by constant use and washing with a mild dish soap.[citation needed]
# Removal
"This kitchen version of electrostripping is safe and easy. It's especially useful for removing tarnish from flatware and holloware. In a pot lined with aluminum foil, mix a diluted solution of equal parts of baking soda salt, and liquid soap. A quarter cup of each to a gallon of water is a typical mixture. Set the sterling in the pot; bring the mix to a simmer and allow it to stand for 10-20 minutes as the oxides are transferred to the aluminum, which you'll see is darkened. Throw that away and wash the silver before using it".[1]
Another way to treat tarnish is to put a drop of water and some fluoride toothpaste on a tissue and rub it on the silver (or metal, but silver is the most common to be targeted by tarnish).[citation needed] | https://www.wikidoc.org/index.php/Tarnish | |
ce793f80fe82762d12cf1feccb7c8308ad41cdd4 | wikidoc | Tatuaje | Tatuaje
Tatuaje is a brand of hand-made premium cigar owned by Tatuaje Cigars, Inc.. It was
created by Pete Johnson (owner of Tatuaje Cigars) in close consultation with José "Pepin" Garcia and is manufactured at the El Rey de los Habanos factory in Miami, Florida, and at Tabacalera Cubana S. A. (TACUBA) in Estelí, Nicaragua.
# Background and History
Tatuaje means "tattoo" in Spanish, and the name reflects Pete Johnson's tattoos. The brand was developed by Pete and Don Pepin, who worked in a very close collaboration to achieve the blend that Pete was seeking.
Tatuaje was the first brand that Don Pepin made on his own. The first Tatuajes were released in 2003. In the October, 2004, issue of Cigar Aficionado (CA), the Tatuaje Cabinet Especiales was given a rating of 90. The brand continues to get high ratings.
# Awards/Recognition/Ratings
- The Tatuaje Cabinet Especiales was designated one of the 25 Best Cigars of 2004 by Cigar Aficionado magazine.
- The Tatuaje Cabinet Taino was designated by Cigar Aficionado as no.4 in the 25 Best Cigars for 2005.
- The Tatuaje Cabinet Noella was designated as no. 9 in the 25 Best Cigars for 2006. and was given a 92 rating at that time.
- Leaf and Ale named the Tatuaje brand as the 2006 Cigar of the Year.
- Tatuaje has consistently been given high ratings in Cigar Aficionado magazine as well as Cigar Insider Online.
- Tatuaje J21 Reserva was praised in Maxim Magazine's August 2007 print issue.
# Description
The cigars can all be considered full-bodied cigars, but vary in strength. All are Nicaraguan Puros (constructed solely of tobaccos grown in Nicaragua). The brand consists of four ranges of regular production cigars along with several limited release vitolas (specific sizes) manufactured specifically for certain retailers.
# Regular Production
## Tatuaje Cabinet
There are six (6) vitolas in this range. Seven are listed below, although the Petit is technically not a Cabinet vitola, but is unique to itself. The band is a simple brown band with white lettering. The Cabinet range uses a Corojo 99 viso wrapper, although those chosen for the Especiales are lighter in color. The filler blends vary, resulting in a range of strength from the refined mellowness of the Especiales to the near-Cuban strength of the Cazadores. A bit of trivia: the first initials of the first six vitolas as given here spell out the name of one of Pete's dogs, Hunter.
## Tatuaje Reserva
There are three (3) vitolas in this range. Again, the filler blends vary. The wrapper used is a Nicaraguan viso, except for the J21, which uses a ligero leaf. The cigars sport a second band, black with Reserva and the frontmark in gold lettering.
## Tatuaje RC
There are but two vitolas in this range, both figurados. They are medium-bodied cigars which start out strong, then mellow gradually over the length of the cigar. The band is tri-colored, with red, white and blue stripes, and each cigar is foil wrapped from the head to the mid-section, similar to the old Cuban style of foil-wrapped figurados. The numbers in the vitola name is the length in millimeters.
## Tatuaje Cojonu
The three vitolas in this range are full-bodied cigars. Beginning in August of 2006, the wrapper was changed to a ligero from a viso wrapper. In addition to the regular Tatuaje band, there is a second, gold band with the year of that vitola's introduction in black. The Gran Cojonu, however, is bandless. In addition, it has a shag (untrimmed) foot. The year in the model name refers to the year of introduction. Thus, the Cojonu 2003 was introduced in 2003. Plans are to introduce a new model every three years.
A new model/vitola of the Cojonu will be introduced every three years.
## Series P
This range is a medium-filler cigar (60% medium filler, 40% long-filler). Medium bodied, it is a Nicaraguan puro, and uses the same filler blend as the Havana VI, and is made at TACUBA in Estelí, Nicaragua. The wrapper is Nicaraguan Habano and the binder is, of course, also Nicaraguan.
## Nuevitas Jibaro
The Nuevitas Jibaro is actually not part of the Tatuaje line and was created by Pete Johnson. Although Pepin Garcia is usually associated with Mr. Johnson's cigars, he was not involved in the creation or production of this small line. They were made by Pedro Martin's old Tropical Tobacco (since purchased by AGANORSA and now known as Tabacalera Tropical)in Estelí, Nicaragua. The design of the cigar was modeled after a custom-rolled Cuban Cohiba. It was a very strong blend. Mr. Johnson discontinued production of the cigar rather than have the production moved to another factory.
The cigars were unbanded with an unfinished foot and the line was limited to two vitolas, both figurados, the No. 1 (5 x 54) and the No. 2 (6 x 52).
# Special Productions
- Bombazos (4" x 46) were produced for Fumare Cigar in Reno, Nevada. It is a strong, spicy blend.
- El Cohete (4" x 50) was produced for Tower Cigars. It was packed in cabinets of 25, each numbered, dated and signed by Pete Johnson. There were only 50 such cabinets available. It was made in Pepin Garcia's Miami factory.
- La Maravilla (5 5/8" x 46) was produced for Leaf and Ale. The wrapper is an aged viso wrapper, with the wrapper covering the foot of the cigar, similar to the Gran Cojonu. The cigars are packed in foil, which is part of a unique fermentation process that is used on the cigars: they are rolled, then wrapped in foil to seal in the flavors, and aged in that form, similar to how some Cuban cigars are aged wrapped in burlap.
# Other Tatuaje Cigars
- In November of 2006 a special production of Tatuaje Noellas Reservas was released to Tatuaje retailers.
- The Thermonuclear, a Triple Ligero, was a 'fun experiment' not generally offered for sale due to its strength, as the name implies.
# See Also
- Photos and more information can be found at Vitolas.net
- Moretti, Michael. Tatooed Cigars. Cigar Aficionado online, 11 August 2003.
- Perelman, Richard B. Perelman's Pocket Cyclopedia of Cigars, 2006 edn. Los Angeles: Perelman, Pioneer & Co., (2005). p. 524-525.
# Notes
- ↑ Comment by Pete Johnson on Cigar Family forum
- ↑ Cigar Aficionado Daily Cigar News, by Michael Moretti, 11 August 2003.
- ↑ CA Cigar of the Week
- ↑ Cabinet Taino rated 92, CA, December, 2005.
- ↑ Cigar Aficionado, February, 2007, p. 66
- ↑ February, June, August, October, December, 2006 issues; January, August 2007 issues as well as numerous Cigar Insider issues.
- ↑ Tatuaje page at vitolas.net
- ↑ Series P information page at company website.
- ↑ Tobacco Europe article, 01 Sep 2002.
- ↑ Nicaragua: Growing by Leaps & Bounds, by E. Edward Hoyt III, SmokeShop Magazine, December, 2003.
- ↑ Much of the information in this account was provided by Pete Johnson, in litt, April, 2007 | Tatuaje
Tatuaje is a brand of hand-made premium cigar owned by Tatuaje Cigars, Inc.. It was
created by Pete Johnson (owner of Tatuaje Cigars) in close consultation with José "Pepin" Garcia and is manufactured at the El Rey de los Habanos factory in Miami, Florida, and at Tabacalera Cubana S. A. (TACUBA) in Estelí, Nicaragua.
# Background and History
Tatuaje means "tattoo" in Spanish, and the name reflects Pete Johnson's tattoos. The brand was developed by Pete and Don Pepin, who worked in a very close collaboration to achieve the blend that Pete was seeking.
Tatuaje was the first brand that Don Pepin made on his own.[1] The first Tatuajes were released in 2003.[2] In the October, 2004, issue of Cigar Aficionado (CA), the Tatuaje Cabinet Especiales was given a rating of 90.[3] The brand continues to get high ratings.[4]
# Awards/Recognition/Ratings
- The Tatuaje Cabinet Especiales was designated one of the 25 Best Cigars of 2004 by Cigar Aficionado magazine.
- The Tatuaje Cabinet Taino was designated by Cigar Aficionado as no.4 in the 25 Best Cigars for 2005.
- The Tatuaje Cabinet Noella was designated as no. 9 in the 25 Best Cigars for 2006.[5] and was given a 92 rating at that time.
- Leaf and Ale named the Tatuaje brand as the 2006 Cigar of the Year.
- Tatuaje has consistently been given high ratings in Cigar Aficionado magazine as well as Cigar Insider Online.[6]
- Tatuaje J21 Reserva was praised in Maxim Magazine's August 2007 print issue.
# Description
The cigars can all be considered full-bodied cigars, but vary in strength. All are Nicaraguan Puros (constructed solely of tobaccos grown in Nicaragua). The brand consists of four ranges of regular production cigars along with several limited release vitolas (specific sizes) manufactured specifically for certain retailers.
# Regular Production
## Tatuaje Cabinet
There are six (6) vitolas in this range. Seven are listed below, although the Petit is technically not a Cabinet vitola, but is unique to itself. The band is a simple brown band with white lettering. The Cabinet range uses a Corojo 99 viso wrapper, although those chosen for the Especiales are lighter in color. The filler blends vary, resulting in a range of strength from the refined mellowness of the Especiales to the near-Cuban strength of the Cazadores. A bit of trivia: the first initials of the first six vitolas as given here spell out the name of one of Pete's dogs, Hunter.[7]
## Tatuaje Reserva
There are three (3) vitolas in this range. Again, the filler blends vary. The wrapper used is a Nicaraguan viso, except for the J21, which uses a ligero leaf. The cigars sport a second band, black with Reserva and the frontmark in gold lettering.
## Tatuaje RC
There are but two vitolas in this range, both figurados. They are medium-bodied cigars which start out strong, then mellow gradually over the length of the cigar. The band is tri-colored, with red, white and blue stripes, and each cigar is foil wrapped from the head to the mid-section, similar to the old Cuban style of foil-wrapped figurados. The numbers in the vitola name is the length in millimeters.
## Tatuaje Cojonu
The three vitolas in this range are full-bodied cigars. Beginning in August of 2006, the wrapper was changed to a ligero from a viso wrapper. In addition to the regular Tatuaje band, there is a second, gold band with the year of that vitola's introduction in black. The Gran Cojonu, however, is bandless. In addition, it has a shag (untrimmed) foot. The year in the model name refers to the year of introduction. Thus, the Cojonu 2003 was introduced in 2003. Plans are to introduce a new model every three years.
A new model/vitola of the Cojonu will be introduced every three years.
## Series P
This range is a medium-filler cigar (60% medium filler, 40% long-filler)[8]. Medium bodied, it is a Nicaraguan puro, and uses the same filler blend as the Havana VI, and is made at TACUBA in Estelí, Nicaragua. The wrapper is Nicaraguan Habano and the binder is, of course, also Nicaraguan.
## Nuevitas Jibaro
The Nuevitas Jibaro is actually not part of the Tatuaje line and was created by Pete Johnson. Although Pepin Garcia is usually associated with Mr. Johnson's cigars, he was not involved in the creation or production of this small line. They were made by Pedro Martin's old Tropical Tobacco (since purchased by AGANORSA and now known as Tabacalera Tropical[9][10])in Estelí, Nicaragua. The design of the cigar was modeled after a custom-rolled Cuban Cohiba. It was a very strong blend. Mr. Johnson discontinued production of the cigar rather than have the production moved to another factory.[11]
The cigars were unbanded with an unfinished foot and the line was limited to two vitolas, both figurados, the No. 1 (5 x 54) and the No. 2 (6 x 52).
# Special Productions
- Bombazos (4" x 46) were produced for Fumare Cigar in Reno, Nevada. It is a strong, spicy blend.
- El Cohete (4" x 50) was produced for Tower Cigars. It was packed in cabinets of 25, each numbered, dated and signed by Pete Johnson. There were only 50 such cabinets available. It was made in Pepin Garcia's Miami factory.
- La Maravilla (5 5/8" x 46) was produced for Leaf and Ale. The wrapper is an aged viso wrapper, with the wrapper covering the foot of the cigar, similar to the Gran Cojonu. The cigars are packed in foil, which is part of a unique fermentation process that is used on the cigars: they are rolled, then wrapped in foil to seal in the flavors, and aged in that form, similar to how some Cuban cigars are aged wrapped in burlap.
# Other Tatuaje Cigars
- In November of 2006 a special production of Tatuaje Noellas Reservas was released to Tatuaje retailers.
- The Thermonuclear, a Triple Ligero, was a 'fun experiment' not generally offered for sale due to its strength, as the name implies.
# See Also
- Photos and more information can be found at Vitolas.net
- Moretti, Michael. Tatooed Cigars. Cigar Aficionado online, 11 August 2003.
- Perelman, Richard B. Perelman's Pocket Cyclopedia of Cigars, 2006 edn. Los Angeles: Perelman, Pioneer & Co., (2005). p. 524-525.
# Notes
- ↑ Comment by Pete Johnson on Cigar Family forum
- ↑ Cigar Aficionado Daily Cigar News, by Michael Moretti, 11 August 2003.
- ↑ CA Cigar of the Week
- ↑ Cabinet Taino rated 92, CA, December, 2005.
- ↑ Cigar Aficionado, February, 2007, p. 66
- ↑ February, June, August, October, December, 2006 issues; January, August 2007 issues as well as numerous Cigar Insider issues.
- ↑ Tatuaje page at vitolas.net
- ↑ Series P information page at company website.
- ↑ Tobacco Europe article, 01 Sep 2002.
- ↑ Nicaragua: Growing by Leaps & Bounds, by E. Edward Hoyt III, SmokeShop Magazine, December, 2003.
- ↑ Much of the information in this account was provided by Pete Johnson, in litt, April, 2007
Template:WikiDoc Sources | https://www.wikidoc.org/index.php/Tatuaje | |
cee40f77ba388888493d468473488f7d86fefb2c | wikidoc | Taurine | Taurine
Taurine, or 2-aminoethanesulfonic acid, is an organic acid that is a major constituent of bile, and can be found in lower amounts in the tissues of many animals including humans. Taurine is a derivative of the sulfur-containing (sulfhydryl) amino acid, cysteine. Taurine is the only known naturally occurring sulfonic acid.
Taurine is named after the Latin taurus, which means bull, as it was first isolated from ox bile in 1827 by Austrian scientists Friedrich Tiedemann and Leopold Gmelin. It is often called an amino acid, even in scientific literature, but as it lacks a carboxyl group it is not strictly an amino acid. It does contain a sulfonate group and may be called an amino sulfonic acid. Small polypeptides have been identified which contain taurine but to date no aminoacyl tRNA synthetase has been identified as specifically recognizing taurine and capable of incorporating it onto a tRNA. Also, contrary to popular belief, taurine is not synthesized from bull urine.
# Physiological roles
Taurine is conjugated via its amino terminal group with the bile acids chenodeoxycholic acid and cholic acid to form the bile salts sodium taurochenodeoxycholate and sodium taurocholate (see bile).
The low pKa (1.5) of taurine's sulfonic acid group ensures that this moiety is negatively charged in the pH ranges normally found in the intestinal tract and thus improves the surfactant properties of the cholic acid conjugate.
Taurine has also been implicated in a wide array of other physiological phenomena including inhibitory neurotransmission, long-term potentiation in the striatum/hippocampus, membrane stabilization, feedback inhibition of neutrophil/macrophage respiratory bursts, adipose tissue regulation, and calcium homeostasis.
Prematurely born infants who lack the enzymes needed to convert cystathionine to cysteine may become deficient in taurine. Thus, taurine is a dietary essential nutrient in these individuals and is often added to many infant formulas as a measure of prudence. There is also evidence that taurine in adult humans reduces blood pressure.
Recent studies show that taurine supplements taken by mice on a high-fat diet prevented them from becoming overweight. Studies have yet to be done on the effect of taurine on obesity in humans. Currently taurine is being tested as an anti-manic treatment for bipolar depression. Recent studies have also shown that taurine can influence (and possibly reverse) defects in nerve blood flow, motor nerve conduction velocity, and nerve sensory thresholds in experimental diabetic neuropathic rats. Taurine levels were found to be significantly lower in vegans than in a control group on a standard American diet. Plasma taurine was 78% of control values, and urinary taurine 29%.
In recent years, taurine has become a common ingredient in energy drinks. Taurine is often used in combination with bodybuilding supplements such as creatine and anabolic steroids, partly due to recent findings in mice that taurine alleviates muscle fatigue in strenuous workouts and raises exercise capacity. Taurine is also used in some contact lens solutions.
Taurine has also been shown in diabetic rats to decrease weight and decrease blood sugar.
# Taurine and cats
Taurine is essential for cat health, as a cat cannot synthesize the compound. The absence of taurine causes a cat's retina to slowly degenerate, causing eye problems and (eventually) irreversible blindness. This condition is called central retinal degeneration (CRD).
In addition, taurine deficiency can cause feline dilated cardiomyopathy, and supplementation can reverse left ventricular systolic dysfunction. However, the vegetarian lioness Little Tyke survived for years in captivity without imbibing the normal required dose of Taurine. (Pion et al 1988) Taurine is now a requirement of the AAFCO and any dry or wet food product labeled approved by the AAFCO should have a minimum of 0.1% taurine. For further AAFCO requirements for cats, consult the table here.
# Production
In 1993, approximately 5,000–6,000 t of taurine (synthetic and natural) were produced; 50% for pet food manufacture, 50% in pharmaceutical applications. Synthetic taurine is obtained from isethionic acid (2-hydroxyethanesulfonic acid), which in turn is obtained from the reaction of ethylene oxide with aqueous sodium bisulfite.
# Safety data
Usage above 28.57 PPM in non-alcoholic beverages is deemed non-GRAS as determined by Flavor and Extract Manufacturers Association (FEMA) Expert Panel. A typical energy drink that contains one gram of taurine corresponds to a concentration of about 4.083 ppm.
# Energy drinks
Taurine is an ingredient in many energy drinks and energy products. It is present in the alcoholic drinks Sparks, Spykes, VK blue, and Mobius Infused Lager. It is also contained in the energy drinks Monster (which contains 2000 mg, 1000 per serving), Von Dutch, Red Bull (1000 mg), SoBe Adrenaline Rush (960 mg), NOS (2750 mg), Boo Koo Energy (3000 mg), RedRave (1000 mg), XL, Full Throttle energy drinks (which contains 1194 mg. for a 16 oz. serving, 605 mg. for 8 oz.), and V (500 mg). The Rockstar energy drink, distributed by the Coca-Cola Corp., can contain up to 2000 mg of taurine, depending on the flavor, while Pepsi's SoBe Power Fruit Punch contains 50mg, and SoBe Energy (and its Lean variant) contain 16.5 mg per bottle. It is also in Foosh Energy Mints and Buzz Bites Chocolate Energy Chews, and is one of the main ingredients in the Indonesian energy powder Extra Joss. Both Hogan Energy Drink and WWE RAW Attitude Energy Drink Powered by Socko have 2000 mg per can (1000 mg per serving). Power C Vitamin Water, from Glacéau's line of vitaminwater, contains 25 mg, and their vitaminenergy contains 2000 mg of taurine per can. Wired Energy Drinks X5000 contains 4400 mg of taurine in a 23.5 oz. can. AMP energy drink however, contains a relatively low 10 taurine mg per serving.
Despite its presence in many energy drinks, taurine has not been shown to be energy-giving, however the results of the studies into taurine usage have shown that taurine might help to reduce muscle fatigue. | Taurine
Template:Chembox new
Taurine, or 2-aminoethanesulfonic acid, is an organic acid that is a major constituent of bile, and can be found in lower amounts in the tissues of many animals including humans. [1][2] Taurine is a derivative of the sulfur-containing (sulfhydryl) amino acid, cysteine. Taurine is the only known naturally occurring sulfonic acid.[3]
Taurine is named after the Latin taurus, which means bull, as it was first isolated from ox bile in 1827 by Austrian scientists Friedrich Tiedemann and Leopold Gmelin. It is often called an amino acid, even in scientific literature,[4][5][6] but as it lacks a carboxyl group it is not strictly an amino acid.[7] It does contain a sulfonate group and may be called an amino sulfonic acid. Small polypeptides have been identified which contain taurine but to date no aminoacyl tRNA synthetase has been identified as specifically recognizing taurine and capable of incorporating it onto a tRNA.[8] Also, contrary to popular belief, taurine is not synthesized from bull urine.[9]
# Physiological roles
Taurine is conjugated via its amino terminal group with the bile acids chenodeoxycholic acid and cholic acid to form the bile salts sodium taurochenodeoxycholate and sodium taurocholate (see bile).
The low pKa (1.5) of taurine's sulfonic acid group ensures that this moiety is negatively charged in the pH ranges normally found in the intestinal tract and thus improves the surfactant properties of the cholic acid conjugate.
Taurine has also been implicated in a wide array of other physiological phenomena including inhibitory neurotransmission,[10] long-term potentiation in the striatum/hippocampus, membrane stabilization, feedback inhibition of neutrophil/macrophage respiratory bursts, adipose tissue regulation, and calcium homeostasis.
Prematurely born infants who lack the enzymes needed to convert cystathionine to cysteine may become deficient in taurine. Thus, taurine is a dietary essential nutrient in these individuals and is often added to many infant formulas as a measure of prudence. There is also evidence that taurine in adult humans reduces blood pressure.[11]
Recent studies show that taurine supplements taken by mice on a high-fat diet prevented them from becoming overweight. Studies have yet to be done on the effect of taurine on obesity in humans. Currently taurine is being tested as an anti-manic treatment for bipolar depression.[12] Recent studies have also shown that taurine can influence (and possibly reverse) defects in nerve blood flow, motor nerve conduction velocity, and nerve sensory thresholds in experimental diabetic neuropathic rats.[13][14] Taurine levels were found to be significantly lower in vegans than in a control group on a standard American diet. Plasma taurine was 78% of control values, and urinary taurine 29%.[15]
In recent years, taurine has become a common ingredient in energy drinks. Taurine is often used in combination with bodybuilding supplements such as creatine and anabolic steroids, partly due to recent findings in mice that taurine alleviates muscle fatigue in strenuous workouts and raises exercise capacity.[16] Taurine is also used in some contact lens solutions.
Taurine has also been shown in diabetic rats to decrease weight and decrease blood sugar.[17]
# Taurine and cats
Taurine is essential for cat health, as a cat cannot synthesize the compound. The absence of taurine causes a cat's retina to slowly degenerate, causing eye problems and (eventually) irreversible blindness. This condition is called central retinal degeneration (CRD).[18][19]
In addition, taurine deficiency can cause feline dilated cardiomyopathy, and supplementation can reverse left ventricular systolic dysfunction. However, the vegetarian lioness Little Tyke survived for years in captivity without imbibing the normal required dose of Taurine.[20] (Pion et al 1988) Taurine is now a requirement of the AAFCO and any dry or wet food product labeled approved by the AAFCO should have a minimum of 0.1% taurine. For further AAFCO requirements for cats, consult the table here.
# Production
In 1993, approximately 5,000–6,000 t of taurine (synthetic and natural) were produced; 50% for pet food manufacture, 50% in pharmaceutical applications.[3] Synthetic taurine is obtained from isethionic acid (2-hydroxyethanesulfonic acid), which in turn is obtained from the reaction of ethylene oxide with aqueous sodium bisulfite.[21]
# Safety data
Usage above 28.57 PPM in non-alcoholic beverages is deemed non-GRAS as determined by Flavor and Extract Manufacturers Association (FEMA) Expert Panel. A typical energy drink that contains one gram of taurine corresponds to a concentration of about 4.083 ppm.[citation needed]
# Energy drinks
Taurine is an ingredient in many energy drinks and energy products. It is present in the alcoholic drinks Sparks, Spykes, VK blue, and Mobius Infused Lager. It is also contained in the energy drinks Monster (which contains 2000 mg, 1000 per serving), Von Dutch, Red Bull (1000 mg), SoBe Adrenaline Rush (960 mg), NOS (2750 mg), Boo Koo Energy (3000 mg), RedRave (1000 mg), XL, Full Throttle energy drinks (which contains 1194 mg. for a 16 oz. serving, 605 mg. for 8 oz.), and V (500 mg). The Rockstar energy drink, distributed by the Coca-Cola Corp., can contain up to 2000 mg of taurine, depending on the flavor, while Pepsi's SoBe Power Fruit Punch contains 50mg, and SoBe Energy (and its Lean variant) contain 16.5 mg per bottle. It is also in Foosh Energy Mints and Buzz Bites Chocolate Energy Chews, and is one of the main ingredients in the Indonesian energy powder Extra Joss. Both Hogan Energy Drink and WWE RAW Attitude Energy Drink Powered by Socko have 2000 mg per can (1000 mg per serving). Power C Vitamin Water, from Glacéau's line of vitaminwater, contains 25 mg, and their vitaminenergy contains 2000 mg of taurine per can. Wired Energy Drinks X5000 contains 4400 mg of taurine in a 23.5 oz. can. AMP energy drink however, contains a relatively low 10 taurine mg per serving.
Despite its presence in many energy drinks, taurine has not been shown to be energy-giving, however the results of the studies into taurine usage have shown that taurine might help to reduce muscle fatigue.[22] | https://www.wikidoc.org/index.php/Taurine | |
4f1fb875ef27b2f16b3ed37e32395818a95ac30d | wikidoc | Telokin | Telokin
Telokin (also known as kinase-related protein or KRP) is an abundant protein found in smooth-muscle. It is identical to the C-terminus of myosin light-chain kinase. Telokin may play a role in the stabilization of unphosphorylated smooth-muscle myosin filaments. Because of its origin as the C-terminal end of smooth muscle myosin light chain kinase, it is called "telokin" (from a combination of the Greek telos, "end" and kinase).
# Nomenclature and classification
Telokin's systematic name is ATP: O-phosphotransferase and its recommended name is myosin-light-chain. (EC 2.7.11.18).
The gene MYLK, a muscle member of the immunoglobulin gene superfamily, encodes myosin light chain kinase which is a calcium/calmodulin dependent enzyme. Four transcript variants that produce four isoforms of the calcium/calmodulin dependent enzyme have been identified as well as two transcripts that produce two isoforms of telokin. The two transcrips that produce the two telokin isoforms are the following:
# Catalytic activity and other functional data
Telokin catalyzes the following reaction:
- ATP + myosin-light-chain = ADP + myosin-light-chain phosphate. (Reaction type: phospho group transfer)
It requires Ca2+ and calmodulin for activity. The 20-kDa light chain from smooth muscle myosin is phosphorylated more rapidly than any other acceptor, but light chains from other myosins and myosin itself can act as acceptors, but more slowly.
The Km values of homo sapiens telokin is 0.018 mM at 23–25 °C and pH = 7.5. This enzyme has a pH optimum of 7.4 and temperature optimum of 30 °C.
Telokin is an acidic protein with a PI value of 4-5 and 17-kDa with an amino acid sequence that is identical to the C terminus of the 130-kDa myosin light chain kinase (MLCK), although it is expressed as a separate protein and produced by an alternate promoter of the MLCK gene. Telokin is transcribed from a second promoter, located within an intron, in the 3' region of the MLCK gene. And that is why the concentration of telokin (at least 15 μM) is higher than MLCK concentration.
Telokin has been shown to bind to unphosphorylated myosin filaments and to stimulate myosin mini-filament assembly in vitro. The major mechanism for initiating smooth muscle (SM)2 contraction is the rise in Ca2+ concentration resulting in an increase in 20-kDa myosin regulatory light chain (MLC20) phosphorylation at Ser-19.
# Structure
# Tissue distribution
KRP presence in different tissues has been assessed by immunoblots using anti-KRP antibodies, and by analyses of its mRNA in Northern blot. KRP is an abundant smooth muscles-pecific protein. So far it has not been detected in non-muscle tissues and striated muscles. Its concentration in gizzard muscle is lo-12-fold higher than that of MLCK and only 2-3-fold less than that of myosin. Vascular muscles have a lower KRP/MLCK ratio.
Telokin is expressed at very high levels in intestinal, urinary, and reproductive tract smooth muscle, at lower levels in vascular smooth muscle, and at undetectable levels in skeletal or cardiac muscle or nonmuscle tissues. Although telokin is strongly activated by myocardin and myocardin is highly expressed in vascular smooth muscle cells, there is relatively little expression of telokin in these cells. This suggests that an inhibitory factor must be attenuating the activity of the telokin promoter in vascular smooth muscle cells. One possible candidate for this inhibitory factor is GATA-6
The increase in telokin expression correlated with an increase in the expression of several other smooth muscle-restricted proteins, including smooth muscle myosin and alpha-actin.
Accumulates in individuals with asthma (at protein levels). Induced by tumor necrosis factor (TNF). Repressed by androgens (e.g. R1881).
# Function
Telokin have two related functions in the C-terminal myosin-binding domain of smooth muscle myosin light chain kinase (MLCK). First, telokin stabilizes myosin filaments in the presence of ATP. Second, telokin can modulate the level of myosin light chain phosphorylation. In this latter role, multiple mechanisms have been suggested. One hypothesis is that light chain phosphorylation is diminished by the direct competition of KRP and MLCK for myosin, resulting in a loss of contraction.
Telokin also inhibits the phosphorylation of myosin filaments while having no effect on phosphorylation of the isolated smooth-muscle myosin regulatory light chain (ReLC). However, When telokin was phosphorylated by MLCK, the telokin-induced inhibition of myosin phosphorylation was removed, which indicates the existence of a telokin-dependent modulatory pathway in smooth-muscle regulation. In this part we must say that the phosphorylation of telokin can be enhanced by the concentration of Ca2+ and calmodulin.
Kinase-related protein (telokin) binds to dephosphorylated smooth myosin near the junction between the rod and the catalytic head region (S-I). This interaction is prevented by MLCK-catalysed phosphorylation of myosin and conversely, the rate of myosin phosphorylation is in turn inhibited by KRP in vitro. As a consequence of this, in vivo KRP might slow down the rate of myosin phosphorylation by myosin light chain kinase (MLCK) and, therefore, tension development. When the intracellular Ca2+ level is decreasing, the KRP can also accelerate muscle relaxation by lowering the ratio of phosphorylated to phosphorylated myosin. KRP is also an important structural regulator of myosin filaments. Smooth muscle myosin, under physiological conditions in vitro, can adapt two relatively and different stable conformations. When the myosin is in the extended conformation, it is active and able to combine with other myosin molecules to form thick filaments which are fundamental for effective contraction. Upon ATP binding, the rod part of unphosphorylated myosin molecule folds into thirds, so that the head –rod junction is brought close to the middle of the rod and stabilized there, presumable by interacting with both the 20 KDa light chains and the neck region. This interaction is prevented by the MLCK-dependent light chain phosphorylation, resulting in the unfolding of myosin monomers and their rapid polymerization into filaments.
The binding of KRP to the neck region folded, ATP-bound dephosphorylated myosin also promotes unfolding and filament formation, thus looking like light chain phosphorylation. This could be a physiologically significant phenomenon considering the high concentration of ATP always present in smooth muscle cells. Thus, Kinase-related protein may have a very important role in relaxed smooth muscle by keeping dephosphorylated myosin in the filamentous state ready for the next rapid contractile response. Experiments aimed at testing this hypothesis indicated that under appropriate conditions a small excess of KRP is enough to form an equimolar complex with smooth muscle myosin and to cause its complete polymerization in the presence of ATP. Experiments where it has been tested this hypothesis, indicated that in appropriated conditions, a small excess of KRP is enough to form an equimolar complex with smooth muscle myosin and in the presence of ATP, cause its complete polymerization.
# Pathology
Certain mutations in the MYLK gene are associated with thoracic aortic aneurysms or thoracic aortic dissections. This disease is caused by mutations affecting the gene MYLK. A disease characterized by permanent dilation of the thoracic aorta usually due to degenerative changes in the aortic wall. It is primarily associated with a characteristic histologic appearance known as 'medial necrosis' or 'Erdheim cystic medial necrosis' in which there is degeneration and fragmentation of elastic fibers, loss of smooth muscle cells, and an accumulation of basophilic ground substance.
# The effect of hypoxia
In cats, telokin expression varies inversely with artery diameter except for cerebral arteries where no telokin is observed. Telokin and myosin light chain are distributed uniformly throughout small pulmonary arteries however they do not colocalized. During hypoxia, telokin dephosphorylates, and myosin light chain becomes increasingly phosphorylated in small pulmonary arteries smooth muscle cell, whereas in large pulmonary arteries smooth muscle cell there is no change in either telokin or myosin light chain phosphorylation. When large pulmonary arteries smooth muscle cell were exposed to phenylephrine, myosin light chain phosphorylation increased with no change in telokin phosphorylation. In small pulmonary arteries, phosphorylated telokin may help maintain relaxation under unstimulated conditions, whereas in large pulmonary arteries, telokin's function remains undetermined. | Telokin
Telokin (also known as kinase-related protein or KRP) is an abundant protein found in smooth-muscle. It is identical to the C-terminus of myosin light-chain kinase. Telokin may play a role in the stabilization of unphosphorylated smooth-muscle myosin filaments.[2][3] Because of its origin as the C-terminal end of smooth muscle myosin light chain kinase, it is called "telokin" (from a combination of the Greek telos, "end" and kinase).[4]
# Nomenclature and classification
Telokin's systematic name is ATP:[myosin light chain] O-phosphotransferase and its recommended name is myosin-light-chain. (EC 2.7.11.18).
The gene MYLK, a muscle member of the immunoglobulin gene superfamily, encodes myosin light chain kinase which is a calcium/calmodulin dependent enzyme. Four transcript variants that produce four isoforms of the calcium/calmodulin dependent enzyme have been identified as well as two transcripts that produce two isoforms of telokin. The two transcrips that produce the two telokin isoforms are the following:
# Catalytic activity and other functional data
Telokin catalyzes the following reaction:
- ATP + myosin-light-chain = ADP + myosin-light-chain phosphate. (Reaction type: phospho group transfer)
It requires Ca2+ and calmodulin for activity. The 20-kDa light chain from smooth muscle myosin is phosphorylated more rapidly than any other acceptor, but light chains from other myosins and myosin itself can act as acceptors, but more slowly.[5]
The Km values of homo sapiens telokin is 0.018 mM at 23–25 °C and pH = 7.5. This enzyme has a pH optimum of 7.4 and temperature optimum of 30 °C.[6]
Telokin is an acidic protein with a PI value of 4-5 and 17-kDa with an amino acid sequence that is identical to the C terminus of the 130-kDa myosin light chain kinase (MLCK), although it is expressed as a separate protein and produced by an alternate promoter of the MLCK gene. Telokin is transcribed from a second promoter, located within an intron, in the 3' region of the MLCK gene.[7] And that is why the concentration of telokin (at least 15 μM) is higher than MLCK concentration.
Telokin has been shown to bind to unphosphorylated myosin filaments and to stimulate myosin mini-filament assembly in vitro. The major mechanism for initiating smooth muscle (SM)2 contraction is the rise in Ca2+ concentration resulting in an increase in 20-kDa myosin regulatory light chain (MLC20) phosphorylation at Ser-19.
# Structure
# Tissue distribution
KRP presence in different tissues has been assessed by immunoblots using anti-KRP antibodies, and by analyses of its mRNA in Northern blot.[8][9][10] KRP is an abundant smooth muscles-pecific protein. So far it has not been detected in non-muscle tissues and striated muscles.[9] Its concentration in gizzard muscle is lo-12-fold higher than that of MLCK and only 2-3-fold less than that of myosin.[8] Vascular muscles have a lower KRP/MLCK ratio.[9][11]
Telokin is expressed at very high levels in intestinal, urinary, and reproductive tract smooth muscle, at lower levels in vascular smooth muscle, and at undetectable levels in skeletal or cardiac muscle or nonmuscle tissues. Although telokin is strongly activated by myocardin and myocardin is highly expressed in vascular smooth muscle cells, there is relatively little expression of telokin in these cells. This suggests that an inhibitory factor must be attenuating the activity of the telokin promoter in vascular smooth muscle cells. One possible candidate for this inhibitory factor is GATA-6[12]
The increase in telokin expression correlated with an increase in the expression of several other smooth muscle-restricted proteins, including smooth muscle myosin and alpha-actin.[7]
Accumulates in individuals with asthma (at protein levels).[13] Induced by tumor necrosis factor (TNF).[14] Repressed by androgens (e.g. R1881).[15]
# Function
Telokin have two related functions in the C-terminal myosin-binding domain of smooth muscle myosin light chain kinase (MLCK). First, telokin stabilizes myosin filaments in the presence of ATP. Second, telokin can modulate the level of myosin light chain phosphorylation. In this latter role, multiple mechanisms have been suggested. One hypothesis is that light chain phosphorylation is diminished by the direct competition of KRP and MLCK for myosin, resulting in a loss of contraction.[8]
Telokin also inhibits the phosphorylation of myosin filaments while having no effect on phosphorylation of the isolated smooth-muscle myosin regulatory light chain (ReLC). However, When telokin was phosphorylated by MLCK, the telokin-induced inhibition of myosin phosphorylation was removed, which indicates the existence of a telokin-dependent modulatory pathway in smooth-muscle regulation. In this part we must say that the phosphorylation of telokin can be enhanced by the concentration of Ca2+ and calmodulin.
Kinase-related protein (telokin) binds to dephosphorylated smooth myosin near the junction between the rod and the catalytic head region (S-I). This interaction is prevented by MLCK-catalysed phosphorylation of myosin and conversely, the rate of myosin phosphorylation is in turn inhibited by KRP in vitro.[8] As a consequence of this, in vivo KRP might slow down the rate of myosin phosphorylation by myosin light chain kinase (MLCK) and, therefore, tension development. When the intracellular Ca2+ level is decreasing, the KRP can also accelerate muscle relaxation by lowering the ratio of phosphorylated to phosphorylated myosin. KRP is also an important structural regulator of myosin filaments. Smooth muscle myosin, under physiological conditions in vitro, can adapt two relatively and different stable conformations. When the myosin is in the extended conformation, it is active and able to combine with other myosin molecules to form thick filaments which are fundamental for effective contraction. Upon ATP binding, the rod part of unphosphorylated myosin molecule folds into thirds, so that the head –rod junction is brought close to the middle of the rod and stabilized there, presumable by interacting with both the 20 KDa light chains and the neck region. This interaction is prevented by the MLCK-dependent light chain phosphorylation, resulting in the unfolding of myosin monomers and their rapid polymerization into filaments.
The binding of KRP to the neck region folded, ATP-bound dephosphorylated myosin also promotes unfolding and filament formation, thus looking like light chain phosphorylation. This could be a physiologically significant phenomenon considering the high concentration of ATP always present in smooth muscle cells. Thus, Kinase-related protein may have a very important role in relaxed smooth muscle by keeping dephosphorylated myosin in the filamentous state ready for the next rapid contractile response. Experiments aimed at testing this hypothesis indicated that under appropriate conditions a small excess of KRP is enough to form an equimolar complex with smooth muscle myosin and to cause its complete polymerization in the presence of ATP. Experiments where it has been tested this hypothesis, indicated that in appropriated conditions, a small excess of KRP is enough to form an equimolar complex with smooth muscle myosin and in the presence of ATP, cause its complete polymerization.[11]
# Pathology
Certain mutations in the MYLK gene are associated with thoracic aortic aneurysms or thoracic aortic dissections. This disease is caused by mutations affecting the gene MYLK. A disease characterized by permanent dilation of the thoracic aorta usually due to degenerative changes in the aortic wall. It is primarily associated with a characteristic histologic appearance known as 'medial necrosis' or 'Erdheim cystic medial necrosis' in which there is degeneration and fragmentation of elastic fibers, loss of smooth muscle cells, and an accumulation of basophilic ground substance.[16][17]
# The effect of hypoxia
In cats, telokin expression varies inversely with artery diameter except for cerebral arteries where no telokin is observed. Telokin and myosin light chain are distributed uniformly throughout small pulmonary arteries however they do not colocalized. During hypoxia, telokin dephosphorylates, and myosin light chain becomes increasingly phosphorylated in small pulmonary arteries smooth muscle cell, whereas in large pulmonary arteries smooth muscle cell there is no change in either telokin or myosin light chain phosphorylation. When large pulmonary arteries smooth muscle cell were exposed to phenylephrine, myosin light chain phosphorylation increased with no change in telokin phosphorylation. In small pulmonary arteries, phosphorylated telokin may help maintain relaxation under unstimulated conditions, whereas in large pulmonary arteries, telokin's function remains undetermined.[18] | https://www.wikidoc.org/index.php/Telokin | |
6bbeacdde66ba94b388b51ff373cd9304b70348f | wikidoc | Termite | Termite
Termites, sometimes incorrectly called "white ants", are a group of social insects usually classified at the taxonomic rank of order Isoptera (but see also taxonomy below). As truly social animals, they are termed eusocial along with the ants and some bees and wasps. Termites mostly feed on dead plant material, generally in the form of wood, leaf litter, soil, or animal dung, and about 10% of the estimated 4,000 species (about 2,600 taxonomically known) are economically significant as pests that can cause serious structural damage to buildings, crops or plantation forests. Termites are major detrivores, particularly in the subtropical and tropical regions, and their recycling of wood and other plant matter is of considerable ecological importance.
As eusocial insects, termites live in colonies that, at maturity, number from several hundred to several million individuals. They are a prime example of decentralised, self-organised systems using swarm intelligence and use this cooperation to exploit food sources and environments that could not be available to any single insect acting alone. A typical colony contains nymphs (semi-mature young), workers, soldiers, and reproductive individuals of both genders, sometimes containing several egg-laying queens.
# Social organization
## Reproductives
A female that has flown, mated, and is producing eggs, is called a "queen". Similarly, a male that has flown, mated, and remains in proximity to a queen, is termed a "King". These anthropocentric terms have caused great misunderstanding of colony dynamics. Research using genetic techniques to determine relatedness of colony members is showing that the idea that colonies are only ever headed by a monogamous royal pair is wrong. Multiple pairs of reproductives within a colony are not uncommon. In the families Rhinotermitidae and Termitidae, and possibly others, sperm competition does not seem to occur (male genitalia are very simple and the sperm are anucleate), suggesting that only one male (king) generally mates within the colony.
At maturity, a primary queen has a great capacity to lay eggs. In physogastric species, the queen adds an extra set of ovaries with each moult, resulting in a greatly distended abdomen and increased fecundity, often reported to reach a production of more than two-thousand eggs a day. The distended abdomen increases the queen's body length to several times more than before mating and reduces her ability to move freely, though attendant workers provide assistance. The queen is widely believed to be a primary source of pheromones useful in colony integration, and these are thought to be spread through shared feeding (trophallaxis).
The king grows only slightly larger after initial mating and continues to mate with the queen for life. This is very different from ant colonies, in which a queen mates once with the male(s) and stores the gametes for life, and the male ants die shortly after mating.
The winged (or 'alate') caste, also referred to as the reproductive caste, are generally the only termites with well-developed eyes (although workers of some harvesting species do have well-developed compound eyes, and, in other species, soldiers with eyes occasionally appear). Termites on the path to becoming alates (going through incomplete metamorphosis) form a sub-caste in certain species of termites, functioning as workers ('pseudergates') and also as potential supplementary reproductives. Supplementaries have the ability to replace a dead primary reproductive and, at least in some species, several are recruited once a primary queen is lost.
In areas with a distinct dry season, the alates leave the nest in large swarms after the first good soaking rain of the rainy season. In other regions, flights may occur throughout the year or more commonly in the spring and autumn. Termites are relatively poor fliers and are readily blown downwind in windspeeds of less than 2 kph, shedding their wings soon after landing at an acceptable site, where they mate and attempt to form a nest in damp timber or earth.
## Workers
Worker termites undertake the labours of foraging, food storage, brood, nest maintenance, and some of the defence effort in certain species. Workers are the main caste in the colony for the digestion of cellulose in food and are the most likely to be found in infested wood. This is achieved in one of two ways. In all termite families except the Termitidae, there are flagellate protists in the gut that assist in cellulose digestion. However, in the Termitidae, which account for approximately 60% of all termite species, the flagellates have been lost and this digestive role is taken up, in part, by a consortium of prokaryotic organisms. This simple story, which has been in Entomology textbooks for decades, is complicated by the finding that all studied termites can produce their own cellulase enzymes, and therefore can digest wood in the absence of their symbiotic microbes. Our knowledge of the relationships between the microbial and termite parts of their digestion is still rudimentary. What is true in all termite species, however, is that the workers feed the other members of the colony with substances derived from the digestion of plant material, either from the mouth or anus. This process of feeding of one colony member by another is known as trophallaxis and is one of the keys to the success of the group. It frees the parents from feeding all but the first generation of offspring, allowing for the group to grow much larger and ensuring that the necessary gut symbionts are transferred from one generation to another.
Termite workers are generally blind due to undeveloped eyes. Despite this limitation, they are able to create elaborate nests and tunnel systems using a combination of soil, chewed wood/cellulose, saliva, and faeces. Some species have been known to create such durable walls that industrial machinery has been damaged in an attempt to break their tall mounds. Some African and Australian species have mounds more than 4 metres high. The nest is created and maintained by workers with many distinct features such as housing the brood, water collection through condensation, reproductive chambers, and tunnel networks that effectively provide air conditioning and control the CO2/O2 balance. A few species even practice agriculture, with elaborate fungal gardens which are fed on collected plant matter, providing a nutritious mycelium on which the colony then feeds (see "Diet", below).
## Soldiers
The soldier caste has anatomical and behavioural specializations, providing strength and armour which are primarily useful against ant attack. The proportion of soldiers within a colony varies both within and among species. Many soldiers have jaws so enlarged that they cannot feed themselves, but instead, like juveniles, are fed by workers. The pan-tropical sub-family Nasutitermitinae have soldiers with the ability to exude noxious liquids through either a horn-like nozzle (nasus) or simple hole in the head (fontanelle). Fontanelles which exude defensive secretions are also a feature of the family Rhinotermitidae. Many species are readily identified using the characteristics of the soldiers' heads, mandibles, or nasus. Among the drywood termites, a soldier's globular ("phragmotic") head can be used to block their narrow tunnels. Termite soldiers are usually blind, but in some families, soldiers developing from the reproductive line may have at least partly functional eyes.
It's generally accepted that the specialization of the soldier caste is principally a defence against predation by ants. The wide range of jaw types and phragmotic heads provides methods which effectively block narrow termite tunnels against ant entry. A tunnel-blocking soldier can rebuff attacks from many ants. Usually more soldiers stand by behind the initial soldier so once the first one falls another soldier will take the place. In cases where the intrusion is coming from a breach that is larger than the soldier's head, defence requires special formations where soldiers form a phalanx-like formation around the breach and blindly bite at intruders or shoot toxic glue from the nasus. This formation involves self-sacrifice because once the workers have repaired the breach during fighting, no return is provided, thus causing the death of all the defenders.
Termites undergo incomplete metamorphosis, with their freshly hatched young taking the form of tiny termites that grow without significant morphological changes (other than wings and soldier specializations). Some species of termite have dimorphic soldiers (up to three times the size of smaller soldiers). Though their value is unknown, speculation is that they may function as an elite class that defends only the inner tunnels of the mound. Evidence for this is that, even when provoked, these large soldiers do not defend themselves but retreat deeper into the mound. On the other hand, dimorphic soldiers are common in some Australian species of Schedorhinotermes that neither build mounds nor appear to maintain complex nest structures. Some termite taxa are without soldiers; perhaps the best known of these are the Apicotermitinae.
## Diet
Termites are generally grouped according to their feeding behaviour. Thus, the commonly used general groupings are subterranean, soil-feeding, drywood, dampwood, and grass-eating. Of these, subterraneans and drywoods are primarily responsible for damage to human-made structures.
All termites eat cellulose in its various forms as plant fibre. Cellulose is a rich energy source (as demonstrated by the amount of energy released when wood is burned), but remains difficult to digest. Termites rely primarily upon symbiotic protozoa (metamonads) such as Trichonympha, and other microbes in their gut to digest the cellulose for them and absorb the end products for their own use. Gut protozoa, such as Trichonympha, in turn rely on symbiotic bacteria embedded on their surfaces to produce some of the necessary digestive enzymes. This relationship is one of the finest examples of mutualism among animals. Most so called "higher termites", especially in the Family Termitidae, can produce their own cellulase enzymes. However, they still retain a rich gut fauna and primarily rely upon the bacteria. Due to closely related bacterial species, it is strongly presumed that the termites' gut flora are descended from the gut flora of the ancestral wood-eating cockroaches, like those of the genus Cryptocercus.
Some species of termite practice fungiculture. They maintain a 'garden' of specialized fungi of genus Termitomyces, which are nourished by the excrement of the insects. When the fungi are eaten, their spores pass undamaged through the intestines of the termites to complete the cycle by germinating in the fresh faecal pellets. They are also well known for eating smaller insects in a last resort environment.
## Mounds
Termites build nests to house their colonies. Nests are commonly located in larger timber or in the soil in locations such as growing trees, inside fallen trees, underground, and in above-ground mounds which they construct, commonly called "anthills" in Africa and Australia, despite the technical incorrectness of that name. Mounds occur when the nest grows beyond its initially concealing surface. In tropical savannas the mounds may be very large, with an extreme of 9 metres (30 ft) high in the case of large conical mounds constructed by some Macrotermes species in well-wooded areas in Africa,. Two to three metres, however, would be typical for the largest mounds in most savannas. The shape ranges from somewhat amorphous domes or cones usually covered in grass and/or woody shrubs, to sculptured hard earth mounds, or a mixture of the two. Despite the irregular mound shapes, the different species in an area can usually be identified by simply looking at the mounds.
The sculptured mounds sometimes have elaborate and distinctive forms, such as those of the compass termite (Amitermes meridionalis & A. laurensis) which build tall wedge-shaped mounds with the long axis oriented approximately north-south. This orientation has been experimentally shown to help in thermoregulation.
The column of hot air rising in the above ground mounds helps drive air circulation currents inside the subterranean network. The structure of these mounds can be quite complex. The temperature control is essential for those species that cultivate fungal gardens and even for those that don't, much effort and energy is spent maintaining the brood within a narrow temperature range, often only plus or minus one degree C over a day.
In some parts of the African savanna, a high density of above-ground mounds dominates the landscape. For instance, in some parts of the Busanga Plain area of Zambia, small mounds of about 1 m diameter with a density of about 100 per hectare can be seen on grassland between larger tree- and bush-covered mounds about 25 m in diameter with a density around 1 per hectare, and both show up well on high-resolution satellite images taken in the wet season..
- Cathedral Mounds
Cathedral Mounds
- Magnetic Mounds (nearly North-South Axis)
Magnetic Mounds (nearly North-South Axis)
- Termite cathedral mounds in the Northern Territory of Australia
Termite cathedral mounds in the Northern Territory of Australia
- Two cathedral mounds in a tropical savanna blackened by Kakadu National Park's annual winter bushfires.
Two cathedral mounds in a tropical savanna blackened by Kakadu National Park's annual winter bushfires.
# Human interaction
Because of their wood-eating habits, termites sometimes do great damage to buildings and other wooden structures. Their habit of remaining concealed often results in their presence being undetected until the timbers are severely damaged and exhibit surface changes. Once termites have entered a building, they do not limit themselves to wood; they also damage paper, cloth, carpets, and other cellulosic materials. Often, other soft materials are damaged and may be used for construction. Particles taken from soft plastics, plaster, rubber, and sealants such as silicon rubber and acrylics are often employed in construction.
Termites usually avoid exposure to unfavourable environmental conditions. They tend to remain hidden in tunnels in earth and wood. Where they need to cross an impervious or unfavourable substrate, they cover their tracks with tubing made of faeces, plant matter, and soil. Sometimes these shelter tubes will extend for many metres, such as up the outside of a tree reaching from the soil to dead branches. Termite barrier systems used for protecting buildings aim to prevent concealed termite access, thus forcing the termites out into the open where they must form clearly visible shelter tubes to gain entry.
Termites can be major agricultural pests, particularly in Africa and Asia, where crop losses can be severe. Counterbalancing this is the greatly improved water infiltration where termite tunnels in the soil allow rainwater to soak in deeply and help reduce runoff and consequent soil erosion.
In many cultures, termites are used for food (particularly the alates), and termite nests are used widely in construction (the dirt is often dust-free) and as a soil amendment.
Humans have moved many wood-eating species between continents, but have also caused drastic population decline in others through habitat loss and pesticide application.
## Avoiding termite troubles
Precautions:
- Avoid contact of susceptible timber with ground by using termite-resistant concrete, steel, or masonry foundation with appropriate barriers. Even so, termites are able to bridge these with shelter tubes, and it has been known for termites to chew through piping made of soft plastics and even some metals, such as lead, to exploit moisture. In general, new buildings should be constructed with embedded physical termite barriers so that there are no easy means for termites to gain concealed entry. While barriers of poisoned soil, so called termite pre-treatment, have been in general use since the 1970s, it is preferable that these be used only for existing buildings without effective physical barriers.
- The intent of termite barriers (whether physical, poisoned soil, or some of the new poisoned plastics) is to prevent the termites from gaining unseen access to structures. In most instances, termites attempting to enter a barriered building will be forced into the less favourable approach of building shelter tubes up the outside walls, and thus, they can be clearly visible both to the building occupants and a range of predators. Regular inspection by a competent (trained and experienced) inspector is the best defence.
- Timber treatment.
- Use of timber that is naturally resistant to termites such as Canarium australianum (Turpentine Tree), Callitris glaucophylla (White Cypress), or one of the Sequoias. Note that there is no tree species whose every individual tree yields only timbers that are immune to termite damage, so that even with well known termite-resistant timber types, there will occasionally be pieces that are attacked.
When termites have already penetrated a building, the first action is usually to destroy the colony with insecticides before removing the termites' means of access and fixing the problems that encouraged them in the first place. Baits (feeder stations) with small quantities of disruptive insect hormones or other very slow acting toxins have become the preferred least-toxic management tool in most western countries. This has replaced the dusting of toxins direct into termite tunnels that had been widely done since the early 1930s (originating in Australia). The main dust toxicants have been the inorganic metallic poison arsenic trioxide, insect growth regulators (hormones) such as Triflumuron and, more recently, fipronil. Blowing dusts into termite workings is a highly skilled process. All these slow-acting poisons can be distributed by the workers for hours or weeks before any symptoms occur and are capable of destroying the entire colony. More modern variations include chlorfluazuron, Diflubenzuron, hexaflumuron, and Novaflumuron as bait toxicants and fipronil and imidacloprid as soil poisons. Soil poisons are the least-preferred method of control as this requires much larger doses of toxin and results in uncontrollable release to the environment.
## Termites in the human diet
The alates are nutritious, having a good store of fat and protein, and are palatable in most species with a nutty flavour when cooked. They are easily gathered at the beginning of the rainy season in Central and Southern Africa when they swarm, as they are attracted to lights and can be gathered up when they land on nets put up around a lamp. The wings are shed and can be removed by a technique similar to winnowing. They are best gently roasted on a hot plate or lightly fried until slightly crisp; oil is not usually needed since their bodies are naturally high in oil. Traditionally they make a welcome treat at the beginning of the rainy season when livestock is lean, new crops have not yet produced food, and stored produce from the previous growing season is running low.
# Ecology
Ecologically, termites are important in nutrient recycling, habitat creation, soil formation and quality and, particularly the winged reproductives, as food for countless predators. The role of termites in hollowing timbers and thus providing shelter and increased wood surface areas for other creatures is critical for the survival of a large number of timber-inhabiting species. Larger termite mounds play a role in providing a habitat for plants and animals, especially on plains in Africa that are seasonally inundated by a rainy season, providing a retreat above the water for smaller animals and birds, and a growing medium for woody shrubs with root systems that cannot withstand inundation for several weeks. In addition, scorpions, lizards, snakes, small mammals, and birds live in abandoned or weathered mounds, and aardvarks dig substantial caves and burrows in them, which then become homes for larger animals such as hyenas and mongooses.
As detrivores, termites clear away leaf and woody litter and so reduce the severity of the annual bush fires in African savannas, which are not as destructive as those in Australia and the USA.
Globally, termites are found roughly between 50 degrees North & South, with the greatest biomass in the tropics and the greatest diversity in tropical forests and Mediterranean shrublands. Termites are also considered to be a major source of atmospheric methane, one of the prime greenhouse gases. Termites have been common since at least the Cretaceous period. Termites also eat bone and other parts of carcasses, and their traces have been found on dinosaur bones from the middle Jurassic in China.
## Plant defences against termites
Many plants have developed effective defences against termites, and in most ecosystems, there is an observable balance between the growth of plants and the feeding of termites. Defence is typically achieved by secreting anti-feedant chemicals (such as oils, resins, and lignins) into the woody cell walls. This reduces the ability of termites to efficiently digest the cellulose. Many of the strongly termite-resistant tree species have heartwood timber that is extremely dense (such as Eucalyptus camaldulensis) due to accretion of these resins. Over the years there has been considerable research into these natural defensive chemicals with scientists seeking to add them to timbers from susceptible trees. A commercial product, "Blockaid", has been developed in Australia and uses a range of plant extracts to create a paint-on nontoxic termite barrier for buildings. In 2005, a group of Australian scientists "discovered" (announced) a treatment based on an extract of a species of Eremophila that repels termites. Tests have shown that termites are strongly repelled by the toxic material to the extent that they will starve rather than cross treated samples. When kept in close proximity to the extract, they become disoriented and eventually die. Scientists hope to use this toxic compound commercially to prevent termite feeding.
# Taxonomy, evolution and systematics
Recent DNA evidence has supported the nearly 120-year-old hypothesis, originally based on morphology, that termites are most closely related to the wood-eating cockroaches (genus Cryptocercus), to which the singular and very primitive Mastotermes darwiniensis shows some telltale similarities. Most recently, this has led some authors to propose that termites be reclassified as a single family, Termitidae, within the order Blattaria, which contains cockroaches . However, most researchers advocate the less drastic measure of retaining the termites as Isoptera but as a group subordinate to true roaches, preserving the internal classification of termites .
## Evolutionary history
The oldest unambiguous termite fossils date to the early Cretaceous, although structures from the late Triassic have been interpreted as fossilized termite nests. Given the diversity of Cretaceous termites, it is likely that they had their origin at least sometime in the Jurassic.
It has long been accepted that termites are closely related to cockroaches and mantids, and they are classified in the same superorder (Dictyoptera), but new research has shed light on the details of termite evolution. There is now strong evidence suggesting that termites are really highly modified, social, wood-eating cockroaches. A study conducted by scientists has found that endosymbiotic bacteria from termites and a genus of cockroaches, Cryptocercus, share the strongest phylogenetical similarities out of all other cockroaches. Both termites and Cryptocercus also share similar morphological and social features -- most cockroaches do not show social characteristics, but Cryptocercus takes care of its young and exhibits other social behaviour. As mentioned above, the primitive Giant Northern Termite (Mastotermes darwiniensis) exhibits numerous cockroach-like characteristics that are not shared with other termites.
## Systematics
As of 1996, about 2,800 termite species are recognized, classified in seven families. These are arranged here in a phylogenetic sequence, from the most basal to the most advanced:
- Mastotermitidae (1 species, Mastotermes darwiniensis)
- Hodotermitidae (3 genera, 19 species)
Hodotermitinae
- Hodotermitinae
- Kalotermitidae (22 genera, 419 species)
- Termopsidae (5 genera, 20 species)
Termopsinae
Porotermitinae
Stolotermitinae
- Termopsinae
- Porotermitinae
- Stolotermitinae
- Rhinotermitidae (14 genera, 343 species)
Coptotermitinae Holmgren
Heterotermitinae Froggatt
Prorhinoterminae Quennedey & Deligne, 1975
Psammotermitinae Holmgren
Rhinotermitinae Froggatt
Stylotermitinae Holmgren, K & N, 1917
Termitogetoninae Holmgren
- Coptotermitinae Holmgren
- Heterotermitinae Froggatt
- Prorhinoterminae Quennedey & Deligne, 1975
- Psammotermitinae Holmgren
- Rhinotermitinae Froggatt
- Stylotermitinae Holmgren, K & N, 1917
- Termitogetoninae Holmgren
- Serritermitidae (1 species, Serritermes serrifer)
- Termitidae (236 genera, 1958 species)
Macrotermitinae (14 genera, 349 species)
Nasutitermitinae (91 genera, 663 species)
Amitermitinae (17 genera, 295 species)
Apicotermitinae (43 genera, 202 species)
Cubitermitinae (28 genera, 161 species)
Termitinae (43 genera, 288 species)
- Macrotermitinae (14 genera, 349 species)
- Nasutitermitinae (91 genera, 663 species)
- Amitermitinae (17 genera, 295 species)
- Apicotermitinae (43 genera, 202 species)
- Cubitermitinae (28 genera, 161 species)
- Termitinae (43 genera, 288 species)
The most current classification of termites is summarized by Engel & Krishna (2004).
# Termites as a source of power
One of the US Department of Energy's most enduring goals is to replace fossil fuels with renewable sources of cleaner energy, such as hydrogen produced from plant biomass fermentation. Termites may help reach this goal through metagenomics.
Termites are capable of producing up to two litres of hydrogen from fermenting a single sheet of paper, making them one of the planet's most efficient bioreactors. Termites achieve this high degree of efficiency by exploiting the metabolic capabilities of about 200 different species of microbes that inhabit their hindguts.
Hydrogen is normally created by using electricity to remove hydrogen molecules from water or natural gas, but the electricity is most often generated using fossil fuels that emit carbon pollutants. The microbial community in the termite gut efficiently manufactures large quantities of clean hydrogen. By sequencing the termite's microbial community, it may be possible to get a better understanding of these biochemical pathways.
Termites eat wood but cannot extract energy from the complex lignocellulose polymers within it. These polymers are broken down into simple sugars by fermenting bacteria in the termite's gut and using enzymes that produce hydrogen as a byproduct. A second wave of bacteria uses the simple sugars and hydrogen to make the acetate the termite requires for energy. If it can be determined which enzymes are used to create hydrogen, and which genes produce them, this process could be scaled up with bioreactors to generate hydrogen from woody biomass, such as poplar, in commercial quantities.
Sceptics regard this as unlikely to be a carbon-neutral commercial process due to the energy inputs. For decades, researchers have sought to house termites on a commercial scale (like worm farms) to break down woody debris and paper, but funding has been scarce and the problems of developing a continuous process that does not disrupt the termites' homeostasis have not been overcome.
- Original article
- JGI - Organization responsible for sequencing the termite. | Termite
Termites, sometimes incorrectly called "white ants", are a group of social insects usually classified at the taxonomic rank of order Isoptera (but see also taxonomy below). As truly social animals, they are termed eusocial along with the ants and some bees and wasps. Termites mostly feed on dead plant material, generally in the form of wood, leaf litter, soil, or animal dung, and about 10% of the estimated 4,000 species (about 2,600 taxonomically known) are economically significant as pests that can cause serious structural damage to buildings, crops or plantation forests. Termites are major detrivores, particularly in the subtropical and tropical regions, and their recycling of wood and other plant matter is of considerable ecological importance.
As eusocial insects, termites live in colonies that, at maturity, number from several hundred to several million individuals. They are a prime example of decentralised, self-organised systems using swarm intelligence and use this cooperation to exploit food sources and environments that could not be available to any single insect acting alone. A typical colony contains nymphs (semi-mature young), workers, soldiers, and reproductive individuals of both genders, sometimes containing several egg-laying queens.
# Social organization
## Reproductives
A female that has flown, mated, and is producing eggs, is called a "queen". Similarly, a male that has flown, mated, and remains in proximity to a queen, is termed a "King". These anthropocentric terms have caused great misunderstanding of colony dynamics. Research using genetic techniques to determine relatedness of colony members is showing that the idea that colonies are only ever headed by a monogamous royal pair is wrong. Multiple pairs of reproductives within a colony are not uncommon. In the families Rhinotermitidae and Termitidae, and possibly others, sperm competition does not seem to occur (male genitalia are very simple and the sperm are anucleate), suggesting that only one male (king) generally mates within the colony.
At maturity, a primary queen has a great capacity to lay eggs. In physogastric species, the queen adds an extra set of ovaries with each moult, resulting in a greatly distended abdomen and increased fecundity, often reported to reach a production of more than two-thousand eggs a day. The distended abdomen increases the queen's body length to several times more than before mating and reduces her ability to move freely, though attendant workers provide assistance. The queen is widely believed to be a primary source of pheromones useful in colony integration, and these are thought to be spread through shared feeding (trophallaxis).
The king grows only slightly larger after initial mating and continues to mate with the queen for life. This is very different from ant colonies, in which a queen mates once with the male(s) and stores the gametes for life, and the male ants die shortly after mating.
The winged (or 'alate') caste, also referred to as the reproductive caste, are generally the only termites with well-developed eyes (although workers of some harvesting species do have well-developed compound eyes, and, in other species, soldiers with eyes occasionally appear). Termites on the path to becoming alates (going through incomplete metamorphosis) form a sub-caste in certain species of termites, functioning as workers ('pseudergates') and also as potential supplementary reproductives. Supplementaries have the ability to replace a dead primary reproductive and, at least in some species, several are recruited once a primary queen is lost.
In areas with a distinct dry season, the alates leave the nest in large swarms after the first good soaking rain of the rainy season. In other regions, flights may occur throughout the year or more commonly in the spring and autumn. Termites are relatively poor fliers and are readily blown downwind in windspeeds of less than 2 kph, shedding their wings soon after landing at an acceptable site, where they mate and attempt to form a nest in damp timber or earth.
## Workers
Worker termites undertake the labours of foraging, food storage, brood, nest maintenance, and some of the defence effort in certain species. Workers are the main caste in the colony for the digestion of cellulose in food and are the most likely to be found in infested wood. This is achieved in one of two ways. In all termite families except the Termitidae, there are flagellate protists in the gut that assist in cellulose digestion. However, in the Termitidae, which account for approximately 60% of all termite species, the flagellates have been lost and this digestive role is taken up, in part, by a consortium of prokaryotic organisms. This simple story, which has been in Entomology textbooks for decades, is complicated by the finding that all studied termites can produce their own cellulase enzymes, and therefore can digest wood in the absence of their symbiotic microbes. Our knowledge of the relationships between the microbial and termite parts of their digestion is still rudimentary. What is true in all termite species, however, is that the workers feed the other members of the colony with substances derived from the digestion of plant material, either from the mouth or anus. This process of feeding of one colony member by another is known as trophallaxis and is one of the keys to the success of the group. It frees the parents from feeding all but the first generation of offspring, allowing for the group to grow much larger and ensuring that the necessary gut symbionts are transferred from one generation to another.
Termite workers are generally blind due to undeveloped eyes. Despite this limitation, they are able to create elaborate nests and tunnel systems using a combination of soil, chewed wood/cellulose, saliva, and faeces. Some species have been known to create such durable walls that industrial machinery has been damaged in an attempt to break their tall mounds[citation needed]. Some African and Australian species have mounds more than 4 metres high. The nest is created and maintained by workers with many distinct features such as housing the brood, water collection through condensation, reproductive chambers, and tunnel networks that effectively provide air conditioning and control the CO2/O2 balance. A few species even practice agriculture, with elaborate fungal gardens which are fed on collected plant matter, providing a nutritious mycelium on which the colony then feeds (see "Diet", below).
## Soldiers
The soldier caste has anatomical and behavioural specializations, providing strength and armour which are primarily useful against ant attack. The proportion of soldiers within a colony varies both within and among species. Many soldiers have jaws so enlarged that they cannot feed themselves, but instead, like juveniles, are fed by workers. The pan-tropical sub-family Nasutitermitinae have soldiers with the ability to exude noxious liquids through either a horn-like nozzle (nasus) or simple hole in the head (fontanelle). Fontanelles which exude defensive secretions are also a feature of the family Rhinotermitidae. Many species are readily identified using the characteristics of the soldiers' heads, mandibles, or nasus. Among the drywood termites, a soldier's globular ("phragmotic") head can be used to block their narrow tunnels. Termite soldiers are usually blind, but in some families, soldiers developing from the reproductive line may have at least partly functional eyes.
It's generally accepted that the specialization of the soldier caste is principally a defence against predation by ants. The wide range of jaw types and phragmotic heads provides methods which effectively block narrow termite tunnels against ant entry. A tunnel-blocking soldier can rebuff attacks from many ants. Usually more soldiers stand by behind the initial soldier so once the first one falls another soldier will take the place. In cases where the intrusion is coming from a breach that is larger than the soldier's head, defence requires special formations where soldiers form a phalanx-like formation around the breach and blindly bite at intruders or shoot toxic glue from the nasus. This formation involves self-sacrifice because once the workers have repaired the breach during fighting, no return is provided, thus causing the death of all the defenders.
Termites undergo incomplete metamorphosis, with their freshly hatched young taking the form of tiny termites that grow without significant morphological changes (other than wings and soldier specializations). Some species of termite have dimorphic soldiers (up to three times the size of smaller soldiers). Though their value is unknown, speculation is that they may function as an elite class that defends only the inner tunnels of the mound. Evidence for this is that, even when provoked, these large soldiers do not defend themselves but retreat deeper into the mound. On the other hand, dimorphic soldiers are common in some Australian species of Schedorhinotermes that neither build mounds nor appear to maintain complex nest structures. Some termite taxa are without soldiers; perhaps the best known of these are the Apicotermitinae.
## Diet
Termites are generally grouped according to their feeding behaviour. Thus, the commonly used general groupings are subterranean, soil-feeding, drywood, dampwood, and grass-eating. Of these, subterraneans and drywoods are primarily responsible for damage to human-made structures.
All termites eat cellulose in its various forms as plant fibre. Cellulose is a rich energy source (as demonstrated by the amount of energy released when wood is burned), but remains difficult to digest. Termites rely primarily upon symbiotic protozoa (metamonads) such as Trichonympha, and other microbes in their gut to digest the cellulose for them and absorb the end products for their own use. Gut protozoa, such as Trichonympha, in turn rely on symbiotic bacteria embedded on their surfaces to produce some of the necessary digestive enzymes. This relationship is one of the finest examples of mutualism among animals. Most so called "higher termites", especially in the Family Termitidae, can produce their own cellulase enzymes. However, they still retain a rich gut fauna and primarily rely upon the bacteria. Due to closely related bacterial species, it is strongly presumed that the termites' gut flora are descended from the gut flora of the ancestral wood-eating cockroaches, like those of the genus Cryptocercus.
Some species of termite practice fungiculture. They maintain a 'garden' of specialized fungi of genus Termitomyces, which are nourished by the excrement of the insects. When the fungi are eaten, their spores pass undamaged through the intestines of the termites to complete the cycle by germinating in the fresh faecal pellets.[1][2] They are also well known for eating smaller insects in a last resort environment.
## Mounds
Termites build nests to house their colonies. Nests are commonly located in larger timber or in the soil in locations such as growing trees, inside fallen trees, underground, and in above-ground mounds which they construct, commonly called "anthills" in Africa and Australia, despite the technical incorrectness of that name. Mounds occur when the nest grows beyond its initially concealing surface. In tropical savannas the mounds may be very large, with an extreme of 9 metres (30 ft) high in the case of large conical mounds constructed by some Macrotermes species in well-wooded areas in Africa,[3]. Two to three metres, however, would be typical for the largest mounds in most savannas. The shape ranges from somewhat amorphous domes or cones usually covered in grass and/or woody shrubs, to sculptured hard earth mounds, or a mixture of the two. Despite the irregular mound shapes, the different species in an area can usually be identified by simply looking at the mounds.
The sculptured mounds sometimes have elaborate and distinctive forms, such as those of the compass termite (Amitermes meridionalis & A. laurensis) which build tall wedge-shaped mounds with the long axis oriented approximately north-south. This orientation has been experimentally shown to help in thermoregulation.
The column of hot air rising in the above ground mounds helps drive air circulation currents inside the subterranean network. The structure of these mounds can be quite complex. The temperature control is essential for those species that cultivate fungal gardens and even for those that don't, much effort and energy is spent maintaining the brood within a narrow temperature range, often only plus or minus one degree C over a day.
In some parts of the African savanna, a high density of above-ground mounds dominates the landscape. For instance, in some parts of the Busanga Plain area of Zambia, small mounds of about 1 m diameter with a density of about 100 per hectare can be seen on grassland between larger tree- and bush-covered mounds about 25 m in diameter with a density around 1 per hectare, and both show up well on high-resolution satellite images taken in the wet season.[4].
- Cathedral Mounds
Cathedral Mounds
- Magnetic Mounds (nearly North-South Axis)
Magnetic Mounds (nearly North-South Axis)
- Termite cathedral mounds in the Northern Territory of Australia
Termite cathedral mounds in the Northern Territory of Australia
- Two cathedral mounds in a tropical savanna blackened by Kakadu National Park's annual winter bushfires.
Two cathedral mounds in a tropical savanna blackened by Kakadu National Park's annual winter bushfires.
# Human interaction
Because of their wood-eating habits, termites sometimes do great damage to buildings and other wooden structures. Their habit of remaining concealed often results in their presence being undetected until the timbers are severely damaged and exhibit surface changes. Once termites have entered a building, they do not limit themselves to wood; they also damage paper, cloth, carpets, and other cellulosic materials. Often, other soft materials are damaged and may be used for construction. Particles taken from soft plastics, plaster, rubber, and sealants such as silicon rubber and acrylics are often employed in construction.
Termites usually avoid exposure to unfavourable environmental conditions. They tend to remain hidden in tunnels in earth and wood. Where they need to cross an impervious or unfavourable substrate, they cover their tracks with tubing made of faeces, plant matter, and soil. Sometimes these shelter tubes will extend for many metres, such as up the outside of a tree reaching from the soil to dead branches. Termite barrier systems used for protecting buildings aim to prevent concealed termite access, thus forcing the termites out into the open where they must form clearly visible shelter tubes to gain entry.
Termites can be major agricultural pests, particularly in Africa and Asia, where crop losses can be severe. Counterbalancing this is the greatly improved water infiltration where termite tunnels in the soil allow rainwater to soak in deeply and help reduce runoff and consequent soil erosion.
In many cultures, termites are used for food (particularly the alates), and termite nests are used widely in construction (the dirt is often dust-free) and as a soil amendment.
Humans have moved many wood-eating species between continents, but have also caused drastic population decline in others through habitat loss and pesticide application.
## Avoiding termite troubles
Precautions:
- Avoid contact of susceptible timber with ground by using termite-resistant concrete, steel, or masonry foundation with appropriate barriers. Even so, termites are able to bridge these with shelter tubes, and it has been known for termites to chew through piping made of soft plastics and even some metals, such as lead, to exploit moisture. In general, new buildings should be constructed with embedded physical termite barriers so that there are no easy means for termites to gain concealed entry. While barriers of poisoned soil, so called termite pre-treatment, have been in general use since the 1970s, it is preferable that these be used only for existing buildings without effective physical barriers.
- The intent of termite barriers (whether physical, poisoned soil, or some of the new poisoned plastics) is to prevent the termites from gaining unseen access to structures. In most instances, termites attempting to enter a barriered building will be forced into the less favourable approach of building shelter tubes up the outside walls, and thus, they can be clearly visible both to the building occupants and a range of predators. Regular inspection by a competent (trained and experienced) inspector is the best defence.
- Timber treatment.
- Use of timber that is naturally resistant to termites such as Canarium australianum (Turpentine Tree), Callitris glaucophylla (White Cypress), or one of the Sequoias. Note that there is no tree species whose every individual tree yields only timbers that are immune to termite damage, so that even with well known termite-resistant timber types, there will occasionally be pieces that are attacked.
When termites have already penetrated a building, the first action is usually to destroy the colony with insecticides before removing the termites' means of access and fixing the problems that encouraged them in the first place. Baits (feeder stations) with small quantities of disruptive insect hormones or other very slow acting toxins have become the preferred least-toxic management tool in most western countries. This has replaced the dusting of toxins direct into termite tunnels that had been widely done since the early 1930s (originating in Australia). The main dust toxicants have been the inorganic metallic poison arsenic trioxide, insect growth regulators (hormones) such as Triflumuron and, more recently, fipronil. Blowing dusts into termite workings is a highly skilled process. All these slow-acting poisons can be distributed by the workers for hours or weeks before any symptoms occur and are capable of destroying the entire colony. More modern variations include chlorfluazuron, Diflubenzuron, hexaflumuron, and Novaflumuron as bait toxicants and fipronil and imidacloprid as soil poisons. Soil poisons are the least-preferred method of control as this requires much larger doses of toxin and results in uncontrollable release to the environment.
## Termites in the human diet
The alates are nutritious, having a good store of fat and protein, and are palatable in most species with a nutty flavour when cooked. They are easily gathered at the beginning of the rainy season in Central and Southern Africa when they swarm, as they are attracted to lights and can be gathered up when they land on nets put up around a lamp. The wings are shed and can be removed by a technique similar to winnowing. They are best gently roasted on a hot plate or lightly fried until slightly crisp; oil is not usually needed since their bodies are naturally high in oil. Traditionally they make a welcome treat at the beginning of the rainy season when livestock is lean, new crops have not yet produced food, and stored produce from the previous growing season is running low.
# Ecology
Ecologically, termites are important in nutrient recycling, habitat creation, soil formation and quality and, particularly the winged reproductives, as food for countless predators. The role of termites in hollowing timbers and thus providing shelter and increased wood surface areas for other creatures is critical for the survival of a large number of timber-inhabiting species. Larger termite mounds play a role in providing a habitat for plants and animals, especially on plains in Africa that are seasonally inundated by a rainy season, providing a retreat above the water for smaller animals and birds, and a growing medium for woody shrubs with root systems that cannot withstand inundation for several weeks. In addition, scorpions, lizards, snakes, small mammals, and birds live in abandoned or weathered mounds, and aardvarks dig substantial caves and burrows in them, which then become homes for larger animals such as hyenas and mongooses.
As detrivores, termites clear away leaf and woody litter and so reduce the severity of the annual bush fires in African savannas, which are not as destructive as those in Australia and the USA.
Globally, termites are found roughly between 50 degrees North & South, with the greatest biomass in the tropics and the greatest diversity in tropical forests and Mediterranean shrublands. Termites are also considered to be a major source of atmospheric methane, one of the prime greenhouse gases. Termites have been common since at least the Cretaceous period. Termites also eat bone and other parts of carcasses, and their traces have been found on dinosaur bones from the middle Jurassic in China. [5]
## Plant defences against termites
Many plants have developed effective defences against termites, and in most ecosystems, there is an observable balance between the growth of plants and the feeding of termites. Defence is typically achieved by secreting anti-feedant chemicals (such as oils, resins, and lignins) into the woody cell walls. This reduces the ability of termites to efficiently digest the cellulose. Many of the strongly termite-resistant tree species have heartwood timber that is extremely dense (such as Eucalyptus camaldulensis) due to accretion of these resins. Over the years there has been considerable research into these natural defensive chemicals with scientists seeking to add them to timbers from susceptible trees. A commercial product, "Blockaid", has been developed in Australia and uses a range of plant extracts to create a paint-on nontoxic termite barrier for buildings. In 2005, a group of Australian scientists "discovered" (announced) a treatment based on an extract of a species of Eremophila that repels termites.[6] Tests have shown that termites are strongly repelled by the toxic material to the extent that they will starve rather than cross treated samples. When kept in close proximity to the extract, they become disoriented and eventually die. Scientists hope to use this toxic compound commercially to prevent termite feeding.
# Taxonomy, evolution and systematics
Recent DNA evidence[verification needed] has supported the nearly 120-year-old hypothesis, originally based on morphology, that termites are most closely related to the wood-eating cockroaches (genus Cryptocercus), to which the singular and very primitive Mastotermes darwiniensis shows some telltale similarities. Most recently, this has led some authors to propose that termites be reclassified as a single family, Termitidae, within the order Blattaria, which contains cockroaches [7][8]. However, most researchers advocate the less drastic measure of retaining the termites as Isoptera but as a group subordinate to true roaches, preserving the internal classification of termites [9].
## Evolutionary history
The oldest unambiguous termite fossils date to the early Cretaceous, although structures from the late Triassic have been interpreted as fossilized termite nests.[10] Given the diversity of Cretaceous termites, it is likely that they had their origin at least sometime in the Jurassic.
It has long been accepted that termites are closely related to cockroaches and mantids, and they are classified in the same superorder (Dictyoptera), but new research has shed light on the details of termite evolution.[11] There is now strong evidence suggesting that termites are really highly modified, social, wood-eating cockroaches. A study conducted by scientists has found that endosymbiotic bacteria from termites and a genus of cockroaches, Cryptocercus, share the strongest phylogenetical similarities out of all other cockroaches. Both termites and Cryptocercus also share similar morphological and social features -- most cockroaches do not show social characteristics, but Cryptocercus takes care of its young and exhibits other social behaviour. As mentioned above, the primitive Giant Northern Termite (Mastotermes darwiniensis) exhibits numerous cockroach-like characteristics that are not shared with other termites.
## Systematics
As of 1996, about 2,800 termite species are recognized, classified in seven families[2]. These are arranged here in a phylogenetic sequence, from the most basal to the most advanced:
- Mastotermitidae (1 species, Mastotermes darwiniensis)
- Hodotermitidae (3 genera, 19 species)
Hodotermitinae
- Hodotermitinae
- Kalotermitidae (22 genera, 419 species)
- Termopsidae (5 genera, 20 species)
Termopsinae
Porotermitinae
Stolotermitinae
- Termopsinae
- Porotermitinae
- Stolotermitinae
- Rhinotermitidae (14 genera, 343 species)
Coptotermitinae Holmgren
Heterotermitinae Froggatt
Prorhinoterminae Quennedey & Deligne, 1975
Psammotermitinae Holmgren
Rhinotermitinae Froggatt
Stylotermitinae Holmgren, K & N, 1917
Termitogetoninae Holmgren
- Coptotermitinae Holmgren
- Heterotermitinae Froggatt
- Prorhinoterminae Quennedey & Deligne, 1975
- Psammotermitinae Holmgren
- Rhinotermitinae Froggatt
- Stylotermitinae Holmgren, K & N, 1917
- Termitogetoninae Holmgren
- Serritermitidae (1 species, Serritermes serrifer)
- Termitidae (236 genera, 1958 species)
Macrotermitinae (14 genera, 349 species)
Nasutitermitinae (91 genera, 663 species)
Amitermitinae (17 genera, 295 species)
Apicotermitinae (43 genera, 202 species)
Cubitermitinae (28 genera, 161 species)
Termitinae (43 genera, 288 species)
- Macrotermitinae (14 genera, 349 species)
- Nasutitermitinae (91 genera, 663 species)
- Amitermitinae (17 genera, 295 species)
- Apicotermitinae (43 genera, 202 species)
- Cubitermitinae (28 genera, 161 species)
- Termitinae (43 genera, 288 species)
The most current classification of termites is summarized by Engel & Krishna (2004).
# Termites as a source of power
One of the US Department of Energy's most enduring goals is to replace fossil fuels with renewable sources of cleaner energy, such as hydrogen produced from plant biomass fermentation. Termites may help reach this goal through metagenomics.
Termites are capable of producing up to two litres of hydrogen from fermenting a single sheet of paper, making them one of the planet's most efficient bioreactors. Termites achieve this high degree of efficiency by exploiting the metabolic capabilities of about 200 different species of microbes that inhabit their hindguts.
Hydrogen is normally created by using electricity to remove hydrogen molecules from water or natural gas, but the electricity is most often generated using fossil fuels that emit carbon pollutants. The microbial community in the termite gut efficiently manufactures large quantities of clean hydrogen. By sequencing the termite's microbial community, it may be possible to get a better understanding of these biochemical pathways.
Termites eat wood but cannot extract energy from the complex lignocellulose polymers within it. These polymers are broken down into simple sugars by fermenting bacteria in the termite's gut and using enzymes that produce hydrogen as a byproduct. A second wave of bacteria uses the simple sugars and hydrogen to make the acetate the termite requires for energy. If it can be determined which enzymes are used to create hydrogen, and which genes produce them, this process could be scaled up with bioreactors to generate hydrogen from woody biomass, such as poplar, in commercial quantities.
Sceptics regard this as unlikely to be a carbon-neutral commercial process due to the energy inputs. For decades, researchers have sought to house termites on a commercial scale (like worm farms) to break down woody debris and paper, but funding has been scarce and the problems of developing a continuous process that does not disrupt the termites' homeostasis have not been overcome.
- Original article
- JGI - Organization responsible for sequencing the termite. | https://www.wikidoc.org/index.php/Termite | |
7d1461faa09d8c90619c3484381d9af9628a564e | wikidoc | Theorem | Theorem
In mathematics, a theorem is a statement, often stated in natural language, that can be proved on the basis of explicitly stated or previously agreed assumptions. In logic, a theorem is a statement in a formal language that can be derived by applying rules and axioms from a deductive system. This definition in logic is crucial in fields such as proof theory that study the general properties of provable and unprovable statements.
In all settings, an essential property of theorems is that they are derivable using a fixed set of deduction rules and axioms without any additional assumptions. This is not just a matter of the semantics of the language: the expression that results from a derivation is a syntactic consequence of all the expressions that precede it.
In mathematics, the derivation of a theorem is often interpreted as a proof of the truth of the resulting expression, but different deductive systems can yield other interpretations, depending on the meanings of the derivation rules.
The proofs of theorems have two components, called the hypotheses and the conclusions. The proof of a mathematical theorem is a logical argument demonstrating that the conclusions are a necessary consequence of the hypotheses, in the sense that if the hypotheses are true then the conclusions must also be true, without any further assumptions. The concept of a theorem is therefore fundamentally deductive, in contrast to the notion of a scientific theory, which is empirical.
Although they can be written in a completely symbolic form, theorems are often expressed in a natural language such as English. The same is true of proofs, which are often expressed as logically organised and clearly worded informal arguments intended to demonstrate that a formal symbolic proof can be constructed. Such arguments are typically easier to check than purely symbolic ones — indeed, many mathematicians would express a preference for a proof that not only demonstrates the validity of a theorem, but also explains in some way why it is obviously true. In some cases, a picture alone may be sufficient to prove a theorem.
Because theorems lie at the core of mathematics, they are also central to its aesthetics. Theorems are often described as being "trivial", or "difficult", or "deep", or even "beautiful". These subjective judgements vary not only from person to person, but also with time: for example, as a proof is simplified or better understood, a theorem that was once difficult may become trivial. On the other hand, a deep theorem may be simply stated, but its proof may involve surprising and subtle connections between disparate areas of mathematics. Fermat's last theorem is a particularly well-known example of such a theorem.
# Formal and informal notions
Logically most theorems are of the form of an indicative conditional: if A, then B. Such a theorem does not state that B is always true, only that B must be true if A is true. In this case A is called the hypothesis of the theorem (note that "hypothesis" here is something very different from a conjecture) and B the conclusion. The theorem "If n is an even natural number then n/2 is a natural number" is a typical example in which the hypothesis is that n is an even natural number and the conclusion is that n/2 is also a natural number.
In order to be proven, a theorem must be expressible as a precise, formal statement. Nevertheless, theorems are usually expressed in natural language rather than in a completely symbolic form, with the intention that the reader will be able to produce a formal statement from the informal one. In addition, there are often hypotheses which are understood in context, rather than explicitly stated.
It is common in mathematics to choose a number of hypotheses that are assumed to be true within a given theory, and then declare that the theory consists of all theorems provable using those hypotheses as assumptions. In this case the hypotheses that form the foundational basis are called the axioms (or postulates) of the theory. The field of mathematics known as proof theory studies formal axiom systems and the proofs that can be performed within them.
Some theorems are "trivial," in the sense that they follow from definitions, axioms, and other theorems in obvious ways and do not contain any surprising insights. Some, on the other hand, may be called "deep": their proofs may be long and difficult, involve areas of mathematics superficially distinct from the statement of the theorem itself, or show surprising connections between disparate areas of mathematics. A theorem might be simple to state and yet be deep. An excellent example is Fermat's Last Theorem, and there are many other examples of simple yet deep theorems in number theory and combinatorics, among other areas.
There are other theorems for which a proof is known, but the proof cannot easily be written down. The most prominent examples are the Four color theorem and the Kepler conjecture. Both of these theorems are only known to be true by reducing them to a computational search which is then verified by a computer program. Initially, many mathematicians did not accept this form of proof, but it has become more widely accepted in recent years. The mathematician Doron Zeilberger has even gone so far as to claim that these are possibly the only nontrivial results that mathematicians have ever proved. Many mathematical theorems can be reduced to more straightforward computation, including polynomial identities, trigonometric identities and hypergeometric identities.
# Relation to proof
the notion of a theorem is deeply intertwined with the concept of proof. Indeed, theorems are true precisely in the sense that they possess proofs. Therefore, to establish a mathematical statement as a theorem, the existence of a line of reasoning from axioms in the system (and other, already established theorems) to the given statement must be demonstrated.
Although the proof is necessary to produce a theorem, it is not usually considered part of the theorem. And even though more than one proof may be known for a single theorem, only one proof is required to establish the theorem's validity. The Pythagorean theorem and the law of quadratic reciprocity are contenders for the title of theorem with the greatest number of distinct proofs.
# Theorems in logic
Logic, especially in the field of proof theory, considers theorems as statements (called formulas or well formed formulas) of a formal language. A set of deduction rules, also called transformation rules or a formal grammar, must be provided. These deduction rules tell exactly when a formula can be derived from a set of premises.
Different sets of derivation rules give rise to different interpretations of what it means for an expression to be a theorem. Some derivation rules and formal languages are intended to capture mathematical reasoning; the most common examples use first-order logic. Other deductive systems describe term rewriting, such as the reduction rules for λ calculus.
The definition of theorems as elements of a formal language allows for results in proof theory that study the structure of formal proofs and the structure of provable formulas. The most famous result is Gödel's incompleteness theorem; by representing theorems about basic number theory as expressions in a formal language, and then representing this language within number theory itself, Gödel constructed examples of statements that are neither provable nor disprovable from axiomatizations of number theory.
# Relation with scientific theories
Theorems in mathematics and theories in science are fundamentally different in their epistemology. A scientific theory cannot be proven; its key attribute is that it is falsifiable, that is, it makes predictions about the natural world that are testable by experiments. Any disagreement between prediction and experiment demonstrates the incorrectness of the scientific theory, or at least limits its accuracy or domain of validity. Mathematical theorems, on the other hand, are purely abstract formal statements: the proof of a theorem cannot involve experiments or other empirical evidence in the same way such evidence is used to support scientific theories.
Nonetheless, there is some degree of empiricism and data collection involved in the discovery of mathematical theorems. By establishing a pattern, sometimes with the use of a powerful computer, mathematicians may have an idea of what to prove, and in some cases even a plan for how to set about doing the proof. For example, the Collatz conjecture has been verified for start values up to about 2.88 × 1018. The Riemann hypothesis has been verified for the first 10 trillion zeroes of the zeta function. Neither of these statements is considered to be proven.
Such evidence does not constitute proof. For example, the Mertens conjecture is a statement about natural numbers that is now known to be false, but no explicit counterexample (i.e., a natural number n for which the Mertens function M(n) equals or exceeds the square root of n) is known: all numbers less than 1014 have the Mertens property, and the smallest number which does not have this property is only known to be less than the exponential of 1.59 × 1040, which is approximately 10 to the power 4.3 × 1039. Since the number of particles in the universe is generally considered to be less than 10 to the power 100 (a googol), there is no hope to find an explicit counterexample by exhaustive search at present.
Note that the word "theory" also exists in mathematics, to denote a body of mathematical axioms, definitions and theorems, as in, for example, group theory. There are also "theorems" in science, particularly physics, and in engineering, but they often have statements and proofs in which physical assumptions and intuition play an important role; the physical axioms on which such "theorems" are based are themselves falsifiable.
# Terminology
Theorems are often indicated by several other terms: the actual label "theorem" is reserved for the most important results, whereas results which are less important, or distinguished in other ways, are named by different terminology.
- A proposition is a statement not associated with any particular theorem. This term sometimes connotes a statement with a simple proof.
- A lemma is a "pre-theorem", a statement that forms part of the proof of a larger theorem. The distinction between theorems and lemmas is rather arbitrary, since one mathematician's major result is another's minor claim. Gauss's lemma and Zorn's lemma, for example, are interesting enough that some authors present the nominal lemma without going on to use it in the proof of a theorem.
- A corollary is a proposition that follows with little or no proof from one other theorem or definition. That is, proposition B is a corollary of a proposition A if B can readily be deduced from A.
- A claim is a necessary or independently interesting result that may be part of the proof of another statement. Despite the name, claims must be proved.
There are other terms, less commonly used, which are conventionally attached to proven statements, so that certain theorems are referred to by historical or customary names. For examples:
- Identity, used for theorems which state an equality between two mathematical expressions. Examples include Euler's identity and Vandermonde's identity.
- Rule, used for certain theorems such as Bayes' rule and Cramer's rule, that establish useful formulas.
- Law. Examples include the law of large numbers, the law of cosines, and Kolmogorov's zero-one law.
- Principle. Examples include Harnack's principle, the least upper bound principle, and the pigeonhole principle.
A few well-known theorems have even more idiosyncratic names. The division algorithm a theorem expressing the outcome of division in the natural numbers and more general rings. The Banach–Tarski paradox is a theorem in measure theory that is paradoxical in the sense that it contradicts common intuitions about volume in three-dimensional space.
An unproven statement that is believed to be true is called a conjecture (or sometimes a hypothesis, but with a different meaning from the one discussed above). To be considered a conjecture, a statement must usually be proposed publicly, at which point the name of the proponent may be attached to the conjecture, as with Goldbach's conjecture. Other famous conjectures include the Collatz conjecture and the Riemann hypothesis.
# Layout
A theorem and its proof are typically laid out as follows:
The end of the proof may be signalled by the letters Q.E.D. or by one of the tombstone marks "Template:Unicode" or "Template:Unicode", introduced by Paul Halmos following their usage in magazine articles.
The exact style will depend on the author or publication. Many publications provide instructions or macros for typesetting in the house style.
It is common for a theorem to be preceded by definitions describing the exact meaning of the terms used in the theorem. It is also common for a theorem to be preceded by a number of propositions or lemmas which are then used in the proof. However, lemmas are sometimes embedded in the proof of a theorem, either with nested proofs, or with their proofs presented after the proof of the theorem.
Corollaries to a theorem are either presented between the theorem and the proof, or directly after the proof. Sometimes corollaries have proofs of their own which explain why they follow from the theorem.
# Lore
It has been estimated that over a quarter of a million theorems are proved every year.
The well-known aphorism, "A mathematician is a device for turning coffee into theorems", is probably due to Alfréd Rényi, although it is often attributed to Rényi's colleague Paul Erdős (and Rényi may have been thinking of Erdős), who was famous for the many theorems he produced, the number of his collaborations, and his coffee drinking.
The classification of finite simple groups is regarded by some to be the longest proof of a theorem; it comprises tens of thousands of pages in 500 journal articles by some 100 authors. These papers are together believed to give a complete proof, and there are several ongoing projects to shorten and simplify this proof. | Theorem
In mathematics, a theorem is a statement, often stated in natural language, that can be proved on the basis of explicitly stated or previously agreed assumptions. In logic, a theorem is a statement in a formal language that can be derived by applying rules and axioms from a deductive system. This definition in logic is crucial in fields such as proof theory that study the general properties of provable and unprovable statements.
In all settings, an essential property of theorems is that they are derivable using a fixed set of deduction rules and axioms without any additional assumptions. This is not just a matter of the semantics of the language: the expression that results from a derivation is a syntactic consequence of all the expressions that precede it.
In mathematics, the derivation of a theorem is often interpreted as a proof of the truth of the resulting expression, but different deductive systems can yield other interpretations, depending on the meanings of the derivation rules.
The proofs of theorems have two components, called the hypotheses and the conclusions. The proof of a mathematical theorem is a logical argument demonstrating that the conclusions are a necessary consequence of the hypotheses, in the sense that if the hypotheses are true then the conclusions must also be true, without any further assumptions. The concept of a theorem is therefore fundamentally deductive, in contrast to the notion of a scientific theory, which is empirical.
Although they can be written in a completely symbolic form, theorems are often expressed in a natural language such as English. The same is true of proofs, which are often expressed as logically organised and clearly worded informal arguments intended to demonstrate that a formal symbolic proof can be constructed. Such arguments are typically easier to check than purely symbolic ones — indeed, many mathematicians would express a preference for a proof that not only demonstrates the validity of a theorem, but also explains in some way why it is obviously true. In some cases, a picture alone may be sufficient to prove a theorem.
Because theorems lie at the core of mathematics, they are also central to its aesthetics. Theorems are often described as being "trivial", or "difficult", or "deep", or even "beautiful". These subjective judgements vary not only from person to person, but also with time: for example, as a proof is simplified or better understood, a theorem that was once difficult may become trivial. On the other hand, a deep theorem may be simply stated, but its proof may involve surprising and subtle connections between disparate areas of mathematics. Fermat's last theorem is a particularly well-known example of such a theorem.
# Formal and informal notions
Logically most theorems are of the form of an indicative conditional: if A, then B. Such a theorem does not state that B is always true, only that B must be true if A is true. In this case A is called the hypothesis of the theorem (note that "hypothesis" here is something very different from a conjecture) and B the conclusion. The theorem "If n is an even natural number then n/2 is a natural number" is a typical example in which the hypothesis is that n is an even natural number and the conclusion is that n/2 is also a natural number.
In order to be proven, a theorem must be expressible as a precise, formal statement. Nevertheless, theorems are usually expressed in natural language rather than in a completely symbolic form, with the intention that the reader will be able to produce a formal statement from the informal one. In addition, there are often hypotheses which are understood in context, rather than explicitly stated.
It is common in mathematics to choose a number of hypotheses that are assumed to be true within a given theory, and then declare that the theory consists of all theorems provable using those hypotheses as assumptions. In this case the hypotheses that form the foundational basis are called the axioms (or postulates) of the theory. The field of mathematics known as proof theory studies formal axiom systems and the proofs that can be performed within them.
Some theorems are "trivial," in the sense that they follow from definitions, axioms, and other theorems in obvious ways and do not contain any surprising insights. Some, on the other hand, may be called "deep": their proofs may be long and difficult, involve areas of mathematics superficially distinct from the statement of the theorem itself, or show surprising connections between disparate areas of mathematics.[1] A theorem might be simple to state and yet be deep. An excellent example is Fermat's Last Theorem, and there are many other examples of simple yet deep theorems in number theory and combinatorics, among other areas.
There are other theorems for which a proof is known, but the proof cannot easily be written down. The most prominent examples are the Four color theorem and the Kepler conjecture. Both of these theorems are only known to be true by reducing them to a computational search which is then verified by a computer program. Initially, many mathematicians did not accept this form of proof, but it has become more widely accepted in recent years. The mathematician Doron Zeilberger has even gone so far as to claim that these are possibly the only nontrivial results that mathematicians have ever proved.[1] Many mathematical theorems can be reduced to more straightforward computation, including polynomial identities, trigonometric identities and hypergeometric identities.[2]
# Relation to proof
the notion of a theorem is deeply intertwined with the concept of proof. Indeed, theorems are true precisely in the sense that they possess proofs. Therefore, to establish a mathematical statement as a theorem, the existence of a line of reasoning from axioms in the system (and other, already established theorems) to the given statement must be demonstrated.
Although the proof is necessary to produce a theorem, it is not usually considered part of the theorem. And even though more than one proof may be known for a single theorem, only one proof is required to establish the theorem's validity. The Pythagorean theorem and the law of quadratic reciprocity are contenders for the title of theorem with the greatest number of distinct proofs.
# Theorems in logic
Logic, especially in the field of proof theory, considers theorems as statements (called formulas or well formed formulas) of a formal language. A set of deduction rules, also called transformation rules or a formal grammar, must be provided. These deduction rules tell exactly when a formula can be derived from a set of premises.
Different sets of derivation rules give rise to different interpretations of what it means for an expression to be a theorem. Some derivation rules and formal languages are intended to capture mathematical reasoning; the most common examples use first-order logic. Other deductive systems describe term rewriting, such as the reduction rules for λ calculus.
The definition of theorems as elements of a formal language allows for results in proof theory that study the structure of formal proofs and the structure of provable formulas. The most famous result is Gödel's incompleteness theorem; by representing theorems about basic number theory as expressions in a formal language, and then representing this language within number theory itself, Gödel constructed examples of statements that are neither provable nor disprovable from axiomatizations of number theory.
# Relation with scientific theories
Theorems in mathematics and theories in science are fundamentally different in their epistemology. A scientific theory cannot be proven; its key attribute is that it is falsifiable, that is, it makes predictions about the natural world that are testable by experiments. Any disagreement between prediction and experiment demonstrates the incorrectness of the scientific theory, or at least limits its accuracy or domain of validity. Mathematical theorems, on the other hand, are purely abstract formal statements: the proof of a theorem cannot involve experiments or other empirical evidence in the same way such evidence is used to support scientific theories.
Nonetheless, there is some degree of empiricism and data collection involved in the discovery of mathematical theorems. By establishing a pattern, sometimes with the use of a powerful computer, mathematicians may have an idea of what to prove, and in some cases even a plan for how to set about doing the proof. For example, the Collatz conjecture has been verified for start values up to about 2.88 × 1018. The Riemann hypothesis has been verified for the first 10 trillion zeroes of the zeta function. Neither of these statements is considered to be proven.
Such evidence does not constitute proof. For example, the Mertens conjecture is a statement about natural numbers that is now known to be false, but no explicit counterexample (i.e., a natural number n for which the Mertens function M(n) equals or exceeds the square root of n) is known: all numbers less than 1014 have the Mertens property, and the smallest number which does not have this property is only known to be less than the exponential of 1.59 × 1040, which is approximately 10 to the power 4.3 × 1039. Since the number of particles in the universe is generally considered to be less than 10 to the power 100 (a googol), there is no hope to find an explicit counterexample by exhaustive search at present.
Note that the word "theory" also exists in mathematics, to denote a body of mathematical axioms, definitions and theorems, as in, for example, group theory. There are also "theorems" in science, particularly physics, and in engineering, but they often have statements and proofs in which physical assumptions and intuition play an important role; the physical axioms on which such "theorems" are based are themselves falsifiable.
# Terminology
Theorems are often indicated by several other terms: the actual label "theorem" is reserved for the most important results, whereas results which are less important, or distinguished in other ways, are named by different terminology.
- A proposition is a statement not associated with any particular theorem. This term sometimes connotes a statement with a simple proof.
- A lemma is a "pre-theorem", a statement that forms part of the proof of a larger theorem. The distinction between theorems and lemmas is rather arbitrary, since one mathematician's major result is another's minor claim. Gauss's lemma and Zorn's lemma, for example, are interesting enough that some authors present the nominal lemma without going on to use it in the proof of a theorem.
- A corollary is a proposition that follows with little or no proof from one other theorem or definition. That is, proposition B is a corollary of a proposition A if B can readily be deduced from A.
- A claim is a necessary or independently interesting result that may be part of the proof of another statement. Despite the name, claims must be proved.
There are other terms, less commonly used, which are conventionally attached to proven statements, so that certain theorems are referred to by historical or customary names. For examples:
- Identity, used for theorems which state an equality between two mathematical expressions. Examples include Euler's identity and Vandermonde's identity.
- Rule, used for certain theorems such as Bayes' rule and Cramer's rule, that establish useful formulas.
- Law. Examples include the law of large numbers, the law of cosines, and Kolmogorov's zero-one law.[3]
- Principle. Examples include Harnack's principle, the least upper bound principle, and the pigeonhole principle.
A few well-known theorems have even more idiosyncratic names. The division algorithm a theorem expressing the outcome of division in the natural numbers and more general rings. The Banach–Tarski paradox is a theorem in measure theory that is paradoxical in the sense that it contradicts common intuitions about volume in three-dimensional space.
An unproven statement that is believed to be true is called a conjecture (or sometimes a hypothesis, but with a different meaning from the one discussed above). To be considered a conjecture, a statement must usually be proposed publicly, at which point the name of the proponent may be attached to the conjecture, as with Goldbach's conjecture. Other famous conjectures include the Collatz conjecture and the Riemann hypothesis.
# Layout
A theorem and its proof are typically laid out as follows:
The end of the proof may be signalled by the letters Q.E.D. or by one of the tombstone marks "Template:Unicode" or "Template:Unicode", introduced by Paul Halmos following their usage in magazine articles.
The exact style will depend on the author or publication. Many publications provide instructions or macros for typesetting in the house style.
It is common for a theorem to be preceded by definitions describing the exact meaning of the terms used in the theorem. It is also common for a theorem to be preceded by a number of propositions or lemmas which are then used in the proof. However, lemmas are sometimes embedded in the proof of a theorem, either with nested proofs, or with their proofs presented after the proof of the theorem.
Corollaries to a theorem are either presented between the theorem and the proof, or directly after the proof. Sometimes corollaries have proofs of their own which explain why they follow from the theorem.
# Lore
It has been estimated that over a quarter of a million theorems are proved every year.[4]
The well-known aphorism, "A mathematician is a device for turning coffee into theorems", is probably due to Alfréd Rényi, although it is often attributed to Rényi's colleague Paul Erdős (and Rényi may have been thinking of Erdős), who was famous for the many theorems he produced, the number of his collaborations, and his coffee drinking.[5]
The classification of finite simple groups is regarded by some to be the longest proof of a theorem; it comprises tens of thousands of pages in 500 journal articles by some 100 authors. These papers are together believed to give a complete proof, and there are several ongoing projects to shorten and simplify this proof.[6]
Template:Wiktionarypar | https://www.wikidoc.org/index.php/Theorem | |
763073e8e378c52072b3fbbfff0b6b9cb6309c9f | wikidoc | Theriac | Theriac
Theriac or theriaca was a medical concoction made of opium, flesh of viper and a large number of other ingredients. It was originally invented as an antidote against snake venom and later used as a preventative panacea.
The word theriac comes from the Greek term theriaka, which refers to ancient bestiaries about dangerous beasts and their bites. Hence the antidote against animal bites came to be called a theriac, and it later became the English word treacle, via Middle English triacle.
# History
According to legends, the history of theriac begins with the king Mithridates VI of Pontus who experimented with poisons and antidotes on his prisoners. His numerous toxicity experiments eventually led him to declare that he had discovered an antidote for every venomous reptile and poisonous substance. He mixed all the effective antidotes into a single one, mithridatium or mithridate. Mithridate contained opium, myrrh, saffron, ginger, cinnamon and castor, along with some forty other ingredients. When the Romans defeated him, his medical notes fell into their hands and Roman medici began to use them. Emperor Nero's physician Andromachus improved upon mithridatum by bringing the total number of ingredients to sixty four, including viper's flesh. This medicine, called Theriaca andromachi or Venice treacle, was considered especially efficacious against snakebite although, in modern standards, the mixture would be an addictive tranquilliser. The Venice treacle became the traditional Theriac.
Greek physician Galen devoted a whole book Theriaké to theriac. One of his patients, Roman emperor Marcus Aurelius, took it on regular basis.
In 667, ambassadors from Rûm presented the emperor of Tang with a theriaca. The Chinese observed that it contained the gall of swine, was dark red in colour and the foreigners seemed to to respect it greatly. The Tang pharmacologist Su Kung noted down that it had proved its usefulness against "the hundred ailments". Whether this panacea contained the traditional ingredients such as opium, myrrh and hemp, is not known.
# Traditional theriac
The production of a proper theriac took months with all the collection and fermentation of herbs and other ingredients.It was supposed to be left to mature for years. It was also expensive and hence available only for the rich.
Patients would use theriac for bites but also as a preventative against any kind of poisoning and eventually against just about anything. It was used in salves and plasters or just eaten in chunks.
Theriaca andromachi or Venice Treacle contained 64 ingredients. In addition to viper flesh and opium, it included cinnamon, agarics and gum arabic. The ingredients were pulverised and reduced to an electuary with honey.
By the time of the Renaissance, the making of theriac had become an official ceremony, especially in Italy. Pharmacists sold it as late as 1884.
# Notes
- ↑ "Merriam-Webster's Online Dictionary: treacle". Merriam-Webster. Retrieved 2007-02-28..mw-parser-output cite.citation{font-style:inherit}.mw-parser-output q{quotes:"\"""\"""'""'"}.mw-parser-output code.cs1-code{color:inherit;background:inherit;border:inherit;padding:inherit}.mw-parser-output .cs1-lock-free a{background:url("")no-repeat;background-position:right .1em center}.mw-parser-output .cs1-lock-limited a,.mw-parser-output .cs1-lock-registration a{background:url("")no-repeat;background-position:right .1em center}.mw-parser-output .cs1-lock-subscription a{background:url("")no-repeat;background-position:right .1em center}.mw-parser-output .cs1-subscription,.mw-parser-output .cs1-registration{color:#555}.mw-parser-output .cs1-subscription span,.mw-parser-output .cs1-registration span{border-bottom:1px dotted;cursor:help}.mw-parser-output .cs1-hidden-error{display:none;font-size:100%}.mw-parser-output .cs1-visible-error{display:none;font-size:100%}.mw-parser-output .cs1-subscription,.mw-parser-output .cs1-registration,.mw-parser-output .cs1-format{font-size:95%}.mw-parser-output .cs1-kern-left,.mw-parser-output .cs1-kern-wl-left{padding-left:0.2em}.mw-parser-output .cs1-kern-right,.mw-parser-output .cs1-kern-wl-right{padding-right:0.2em}
- ↑ Jump up to: 2.0 2.1 Template:Harv
- ↑ Template:Harv | Theriac
Theriac or theriaca was a medical concoction made of opium, flesh of viper and a large number of other ingredients. It was originally invented as an antidote against snake venom and later used as a preventative panacea.
The word theriac comes from the Greek term theriaka, which refers to ancient bestiaries about dangerous beasts and their bites. Hence the antidote against animal bites came to be called a theriac, and it later became the English word treacle, via Middle English triacle.[1]
# History
According to legends, the history of theriac begins with the king Mithridates VI of Pontus who experimented with poisons and antidotes on his prisoners. His numerous toxicity experiments eventually led him to declare that he had discovered an antidote for every venomous reptile and poisonous substance. He mixed all the effective antidotes into a single one, mithridatium or mithridate. Mithridate contained opium, myrrh, saffron, ginger, cinnamon and castor, along with some forty other ingredients.[2] When the Romans defeated him, his medical notes fell into their hands and Roman medici began to use them. Emperor Nero's physician Andromachus improved upon mithridatum by bringing the total number of ingredients to sixty four, including viper's flesh.[2] This medicine, called Theriaca andromachi or Venice treacle, was considered especially efficacious against snakebite although, in modern standards, the mixture would be an addictive tranquilliser. The Venice treacle became the traditional Theriac.
Greek physician Galen devoted a whole book Theriaké to theriac. One of his patients, Roman emperor Marcus Aurelius, took it on regular basis.
In 667, ambassadors from Rûm presented the emperor of Tang with a theriaca. The Chinese observed that it contained the gall of swine, was dark red in colour and the foreigners seemed to to respect it greatly. The Tang pharmacologist Su Kung noted down that it had proved its usefulness against "the hundred ailments". Whether this panacea contained the traditional ingredients such as opium, myrrh and hemp, is not known.[3]
# Traditional theriac
The production of a proper theriac took months with all the collection and fermentation of herbs and other ingredients.It was supposed to be left to mature for years. It was also expensive and hence available only for the rich.
Patients would use theriac for bites but also as a preventative against any kind of poisoning and eventually against just about anything. It was used in salves and plasters or just eaten in chunks.
Theriaca andromachi or Venice Treacle contained 64 ingredients. In addition to viper flesh and opium, it included cinnamon, agarics and gum arabic. The ingredients were pulverised and reduced to an electuary with honey.
By the time of the Renaissance, the making of theriac had become an official ceremony, especially in Italy. Pharmacists sold it as late as 1884.
# Notes
- ↑ "Merriam-Webster's Online Dictionary: treacle". Merriam-Webster. Retrieved 2007-02-28..mw-parser-output cite.citation{font-style:inherit}.mw-parser-output q{quotes:"\"""\"""'""'"}.mw-parser-output code.cs1-code{color:inherit;background:inherit;border:inherit;padding:inherit}.mw-parser-output .cs1-lock-free a{background:url("https://upload.wikimedia.org/wikipedia/commons/thumb/6/65/Lock-green.svg/9px-Lock-green.svg.png")no-repeat;background-position:right .1em center}.mw-parser-output .cs1-lock-limited a,.mw-parser-output .cs1-lock-registration a{background:url("https://upload.wikimedia.org/wikipedia/commons/thumb/d/d6/Lock-gray-alt-2.svg/9px-Lock-gray-alt-2.svg.png")no-repeat;background-position:right .1em center}.mw-parser-output .cs1-lock-subscription a{background:url("https://upload.wikimedia.org/wikipedia/commons/thumb/a/aa/Lock-red-alt-2.svg/9px-Lock-red-alt-2.svg.png")no-repeat;background-position:right .1em center}.mw-parser-output .cs1-subscription,.mw-parser-output .cs1-registration{color:#555}.mw-parser-output .cs1-subscription span,.mw-parser-output .cs1-registration span{border-bottom:1px dotted;cursor:help}.mw-parser-output .cs1-hidden-error{display:none;font-size:100%}.mw-parser-output .cs1-visible-error{display:none;font-size:100%}.mw-parser-output .cs1-subscription,.mw-parser-output .cs1-registration,.mw-parser-output .cs1-format{font-size:95%}.mw-parser-output .cs1-kern-left,.mw-parser-output .cs1-kern-wl-left{padding-left:0.2em}.mw-parser-output .cs1-kern-right,.mw-parser-output .cs1-kern-wl-right{padding-right:0.2em}
- ↑ Jump up to: 2.0 2.1 Template:Harv
- ↑ Template:Harv | https://www.wikidoc.org/index.php/Theriac | |
bf71c148595772a2e95fcba1286f6d1cd3ed907d | wikidoc | Thionin | Thionin
Thionin, also known as thionin acetate or Lauth's violet, is a strongly staining metachromatic dye that is widely used for biological staining. Stainsfile entry: Thionin can also be used in place of Schiff reagent in quantitative Feulgen staining of DNA. It can also be used to mediate electron transfer in microbial fuel cells.
Thionins can also refer to a family of peptides found solely in higher plants. Typically, a thionin consists of 45-48 amino acid residues. 6-8 of these are cysteine forming 3-4 disulfide bonds. Some thionins have cytotoxic activity and they are therefore interesting in the development of new drugs against cancer with novel action mechanisms.
As of yet, no thionin has ever been developed into an anti-cancer drug.
# Notes and references
- ↑ Florack DE,Stiekema WJ., Thionins: properties, possible biological roles and mechanisms of action., Plant Mol Biol. 1994 Oct;26(1):25-37.
sv:Tionin | Thionin
Thionin, also known as thionin acetate or Lauth's violet, is a strongly staining metachromatic dye that is widely used for biological staining. Stainsfile entry:[1] Thionin can also be used in place of Schiff reagent in quantitative Feulgen staining of DNA. It can also be used to mediate electron transfer in microbial fuel cells.
Thionins can also refer to a family of peptides found solely in higher plants. Typically, a thionin consists of 45-48 amino acid residues. 6-8 of these are cysteine forming 3-4 disulfide bonds. Some thionins have cytotoxic activity and they are therefore interesting in the development of new drugs against cancer with novel action mechanisms. [1] [2]
As of yet, no thionin has ever been developed into an anti-cancer drug.
# Notes and references
- ↑ Florack DE,Stiekema WJ., Thionins: properties, possible biological roles and mechanisms of action., Plant Mol Biol. 1994 Oct;26(1):25-37.
sv:Tionin
Template:WH
Template:WikiDoc Sources | https://www.wikidoc.org/index.php/Thionin | |
6b09074b26dee9a720a5094ce01f80835c5a403c | wikidoc | Thyroid | Thyroid
The thyroid is one of the largest endocrine glands in the body. This gland is found in the neck inferior to (below) the mouth and at approximately the same level as the cricoid cartilage. The thyroid controls how quickly the body burns energy, makes proteins, and how sensitive the body should be to other hormones.
The thyroid participates in these processes by producing thyroid hormones, principally thyroxine (T4) and triiodothyronine (T3). These hormones regulate the rate of metabolism and affect the growth and rate of function of many other systems in the body. Iodine is an essential component of both T3 and T4. The thyroid also produces the hormone calcitonin, which plays a role in calcium homeostasis.
The thyroid is controlled by the hypothalamus and pituitary. The gland gets its name from the Greek word for "shield", after its shape, a double-lobed structure. Hyperthyroidism (overactive thyroid) and hypothyroidism (underactive thyroid) are the most common problems of the thyroid gland. Specialists are called thyroidologists.
# Anatomy
The thyroid is situated on the anterior side of the neck, starting at the oblique line on the thyroid cartilage (just below the laryngeal prominence or Adam's apple), and extending to the 6th Tracheal ring (C-shaped cartilagenous ring of the trachea). It is inappropriate to demarcate the gland's upper and lower border with vertebral levels as it moves position in relation to these during swallowing. It lies over the trachea and is covered by layers of pretracheal fascia (allowing it to move), muscle and skin.
The thyroid is one of the larger endocrine glands - 10-20 grams in adults - and butterfly-shaped. The wings correspond to the lobes and the body to the isthmus of the thyroid. The isthmus overlies tracheal rings 2, 3 and 4. The thyroid may enlarge substantially during pregnancy and when affected by a variety of diseases.
## Embryological development
In the fetus, at 3-4 weeks of gestation, the thyroid gland appears as an epithelial proliferation in the floor of the pharynx at the base of the tongue between the tuberculum impar and the copula linguae at a point latter indicated by the foramen cecum. Subsequently the thyroid descends in front of the pharyngeal gut as a bilobed diverticulum through the thyroglossal duct. Over the next few weeks, it migrates to the base of the neck. During migration, the thyroid remains connected to the tongue by a narrow canal, the thyroglossal duct.
Follicles of the thyroid begin to make colloid in the 11th week and thyroxine by the 18th week.
- Floor of pharynx of embryo between 18 and 21 days.
## Histology
At the microscopic level, there are three primary features of the thyroid:
# Physiology
The primary function of the thyroid is production of the hormones thyroxine (T4), triiodothyronine (T3), and calcitonin. Up to 80% of the T4 is converted to T3 by peripheral organs such as the liver, kidney and spleen. T3 is about ten times more active than T4.
## T3 and T4 production and action
Thyroxine is synthesised by the follicular cells from free tyrosine and on the tyrosine residues of the protein called thyroglobulin (TG). Iodine is captured with the "iodine trap" by the hydrogen peroxide generated by the enzyme thyroid peroxidase (TPO) and linked to the 3' and 5' sites of the benzene ring of the tyrosine residues on TG, and on free tyrosine. Upon stimulation by the thyroid-stimulating hormone (TSH), the follicular cells reabsorb TG and proteolytically cleave the iodinated tyrosines from TG, forming T4 and T3 (in T3, one iodine is absent compared to T4), and releasing them into the blood. Deiodinase enzymes convert T4 to T3. Thyroid hormone that is secreted from the gland is about 90% T4 and about 10% T3.
Cells of the brain are a major target for the thyroid hormones T3 and T4. Thyroid hormones play a particularly crucial role in brain development during pregnancy. A transport protein (OATP1C1) has been identified that seems to be important for T4 transport across the blood brain barrier. A second transport protein (MCT8) is important for T3 transport across brain cell membranes.
In the blood, T4 and T3 are partially bound to thyroxine-binding globulin, transthyretin and albumin. Only a very small fraction of the circulating hormone is free (unbound) - T4 0.03% and T3 0.3%. Only the free fraction has hormonal activity. As with the steroid hormones and retinoic acid, thyroid hormones cross the cell membrane and bind to intracellular receptors (α1, α2, β1 and β2), which act alone, in pairs or together with the retinoid X-receptor as transcription factors to modulate DNA transcription.
## T3 and T4 regulation
The production of thyroxine and triiodothyronine is regulated by thyroid-stimulating hormone (TSH), released by the anterior pituitary. The thyroid and thyrotropes form a negative feedback loop: TSH production is suppressed when the T4 levels are high, and vice versa. The TSH production itself is modulated by thyrotropin-releasing hormone (TRH), which is produced by the hypothalamus and secreted at an increased rate in situations such as cold (in which an accelerated metabolism would generate more heat). TSH production is blunted by somatostatin (SRIH), rising levels of glucocorticoids and sex hormones (estrogen and testosterone), and excessively high blood iodide concentration.
## Calcitonin
An additional hormone produced by the thyroid contributes to the regulation of blood calcium levels. Parafollicular cells produce calcitonin in response to hypercalcemia. Calcitonin stimulates movement of calcium into bone, in opposition to the effects of parathyroid hormone (PTH). However, calcitonin seems far less essential than PTH, as calcium metabolism remains clinically normal after removal of the thyroid, but not the parathyroids.
It may be used diagnostically as a tumor marker for a form of thyroid cancer (medullary thyroid adenocarcinoma), in which high calcitonin levels may be present and elevated levels after surgery may indicate recurrence. It may even be used on biopsy samples from suspicious lesions (e.g. swollen lymph nodes) to establish whether they are metastasis of the original cancer.
Calcitonin can be used therapeutically for the treatment of hypercalcemia or osteoporosis.
## Significance of iodine
In areas of the world where iodine (essential for the production of thyroxine, which contains four iodine atoms) is lacking in the diet, the thyroid gland can be considerably enlarged, resulting in the swollen necks of endemic goitre.
Thyroxine is critical to the regulation of metabolism and growth throughout the animal kingdom. Among amphibians, for example, administering a thyroid-blocking agent such as propylthiouracil (PTU) can prevent tadpoles from metamorphosing into frogs; conversely, administering thyroxine will trigger metamorphosis.
In humans, children born with thyroid hormone deficiency will have physical growth and development problems, and brain development can also be severely impaired, in the condition referred to as cretinism. Newborn children in many developed countries are now routinely tested for thyroid hormone deficiency as part of newborn screening by analysis of a drop of blood. Children with thyroid hormone deficiency are treated by supplementation with synthetic thyroxine, which enables them to grow and develop normally.
Because of the thyroid's selective uptake and concentration of what is a fairly rare element, it is sensitive to the effects of various radioactive isotopes of iodine produced by nuclear fission. In the event of large accidental releases of such material into the environment, the uptake of radioactive iodine isotopes by the thyroid can, in theory, be blocked by saturating the uptake mechanism with a large surplus of non-radioactive iodine, taken in the form of potassium iodide tablets. While biological researchers making compounds labelled with iodine isotopes do this, in the wider world such preventive measures are usually not stockpiled before an accident, nor are they distributed adequately afterward. One consequence of the Chernobyl disaster was an increase in thyroid cancers in children in the years following the accident.
The use of iodised salt is an efficient way to add iodine to the diet. It has eliminated endemic cretinism in most developed countries, and some governments have made the iodination of flour mandatory. Potassium iodide and Sodium iodide are the most active forms of supplemental iodine.
# Diseases
## Hyper- and hypofunction (affects about 2% of the population)
- Hypothyroidism (underactivity)
Hashimoto's thyroiditis / thyroiditis
Ord's thyroiditis
Postoperative hypothyroidism
Postpartum thyroiditis
Silent thyroiditis
Acute thyroiditis
Iatrogenic hypothyroidism
- Hashimoto's thyroiditis / thyroiditis
- Ord's thyroiditis
- Postoperative hypothyroidism
- Postpartum thyroiditis
- Silent thyroiditis
- Acute thyroiditis
- Iatrogenic hypothyroidism
- Hyperthyroidism (overactivity)
Thyroid storm
Graves-Basedow disease
Toxic thyroid nodule
Toxic nodular struma (Plummer's disease)
Hashitoxicosis
Iatrogenic hyperthyroidism
De Quervain thyroiditis (inflammation starting as hyperthyroidism, can end as hypothyroidism)
- Thyroid storm
- Graves-Basedow disease
- Toxic thyroid nodule
- Toxic nodular struma (Plummer's disease)
- Hashitoxicosis
- Iatrogenic hyperthyroidism
- De Quervain thyroiditis (inflammation starting as hyperthyroidism, can end as hypothyroidism)
## Anatomical problems
- Goitre
Endemic goitre
Diffuse goitre
Multinodular goitre
- Endemic goitre
- Diffuse goitre
- Multinodular goitre
- Lingual thyroid
- Thyroglossal duct cyst
## Tumors
- Thyroid adenoma
- Thyroid cancer
Papillary
Follicular
Medullary
Anaplastic
- Papillary
- Follicular
- Medullary
- Anaplastic
- Lymphomas and metastasis from elsewhere (rare)
## Deficiencies
- Cretinism
Medication linked to thyroid disease includes amiodarone, lithium salts, some types of interferon and IL-2.
# Diagnosis
## Blood tests
- The measurement of thyroid-stimulating hormone (TSH) levels is often used by doctors as a screening test. Elevated TSH levels can signify an inadequate hormone production, while suppressed levels can point at excessive unregulated production of hormone. This only applies to primary dysfunction, i.e. a disruption of the feedback loop at the site of the thyroid itself.
- If TSH is abnormal, decreased or increased levels of thyroid hormones T4 and T3 may be present; these may be determined to confirm this.
- In case of central (secondary or tertiary) thyroid dysfunction TSH concentrations may be normal despite pathological concentrations of T4 or T3.
- Autoantibodies may be detected in various disease states (anti-TG, anti-TPO, TSH receptor stimulating antibodies).
- There are two cancer markers for thyroid derived cancers. Thyroglobulin (TG) for well differentiated papillary or follcular adenocarcinoma, and the rare medullary thyroid cancer has calcitonin as the marker.
- Very infrequently, TBG and transthyretin levels may be abnormal; these are not routinely tested.
## Ultrasound
Nodules of the thyroid may or may not be cancer. Medical ultrasonography can help determine their nature because some of the characteristics of benign and malignant nodules differ. The main characteristics of a thyroid nodule on high frequency thyroid ultrasound are as follows:
Ultrasonography is not always able to separate benign from malignant nodules with complete certainty. In suspicious cases, a tissue sample is often obtained by biopsy for microscopic examination.
## Radioiodine scanning and uptake
Thyroid scintigraphy, imaging of the thyroid with the aid of radioactive iodine, usually iodine-123 (123I), is performed in the nuclear medicine department of a hospital or clinic. Radioiodine collects in the thyroid gland before being excreted in the urine. While in the thyroid the radioactive emissions can be detected by a camera, producing a rough image of the shape (a radiodine scan) and tissue activity (a radioiodine uptake) of the thyroid gland.
A normal radioiodine scan shows even uptake and activity throughout the gland. Irregularity can reflect an abnormally shaped or abnormally located gland, or it can indicate that a portion of the gland is overactive or underactive, different from the rest. For example, a nodule that is overactive ("hot") to the point of suppressing the activity of the rest of the gland is usually a thyrotoxic adenoma, a surgically curable form of hyperthyroidism that is hardly ever malignant. In contrast, finding that a substantial section of the thyroid is inactive ("cold") may indicate an area of non-functioning tissue such as thyroid cancer.
The amount of radioactivity can be counted as an indicator of the metabolic activity of the gland. A normal quantitation of radioiodine uptake demonstrates that about 8 to 35% of the administered dose can be detected in the thyroid 24 hours later. Overactivity or underactivity of the gland as may occur with hypothyroidism or hyperthyroidism is usually reflected in decreased or increased radioiodine uptake. Different patterns may occur with different causes of hypo- or hyperthyroidism.
## Biopsy
A medical biopsy refers to the obtaining of a tissue sample for examination under the microscope or other testing, usually to distinguish cancer from noncancerous conditions. Thyroid tissue may be obtained for biopsy by fine needle aspiration or by surgery.
Needle aspiration has the advantage of being a brief, safe, outpatient procedure that is safer and less expensive than surgery and does not leave a visible scar. Needle biopsies became widely used in the 1980s, but it was recognized that accuracy of identification of cancer was good but not perfect. The accuracy of the diagnosis depends on obtaining tissue from all of the suspicious areas of an abnormal thyroid gland. The reliability of needle aspiration is increased when sampling can be guided by ultrasound, and over the last 15 years, this has become the preferred method for thyroid biopsy in North America.
# Treatment
## Medical treatment
Levothyroxine is a stereoisomer of thyroxine which is degraded much slower and can be administered once daily in patients with hypothyroidism.
Graves' disease may be treated with the thioamide drugs propylthiouracil, carbimazole or methimazole, or rarely with Lugol's solution. Hyperthyroidism as well as thyroid tumors may be treated with radioactive iodine.
Percutaneous Ethanol Injections, PEI, for therapy of recurrent thyroid cysts, and metastatic thyroid cancer lymph nodes, as an alternative to the usual surgical method.
## Surgery
Thyroid surgery is performed for a variety of reasons. A nodule or lobe of the thyroid is sometimes removed for biopsy or for the presence of an autonomously functioning adenoma causing hyperthyroidism. A large majority of the thyroid may be removed, a subtotal thyroidectomy, to treat the hyperthyroidism of Graves' disease, or to remove a goitre that is unsightly or impinges on vital structures.
A complete thyroidectomy of the entire thyroid, including associated lymph nodes, is the preferred treatment for thyroid cancer. Removal of the bulk of the thyroid gland usually produces hypothyroidism, unless the person takes thyroid hormone replacement. Consequently, individuals who have undergone a total thyroidectomy are typically placed on thyroid hormone replacement for the remainder of their lives. Higher than normal doses are often administered to prevent recurrence.
If the thyroid gland must be removed surgically, care must be taken to avoid damage to adjacent structures, the parathyroid glands and the recurrent laryngeal nerve. Both are susceptible to accidental removal and/or injury during thyroid surgery. The parathyroid glands produce parathyroid hormone (PTH), a hormone needed to maintain adequate amounts of calcium in the blood. Removal results in hypoparathyroidism and a need for supplemental calcium and vitamin D each day. In the event the blood supply to any one of the parathyroid glands is endangered through surgery, the parathyroid gland(s) involved may be re-implanted in surrounding muscle tissue. The recurrent laryngeal nerves provide motor control for all external muscles of the larynx except for the cricothyroid muscle, also runs along the posterior thyroid. Accidental laceration of either of the two or both recurrent laryngeal nerves may cause paralysis of the vocal cords and their associated muscles, changing the voice quality.
## Radioiodine therapy
Large goiters that cause symptoms, but do not harbor cancer, after evaluation, and biopsy of suspicious nodules can be treated by an alternative therapy with radioiodine. The iodine uptake can be high in countries with iodine deficiency, but low in iodine sufficient countries. The 1999 release of rhTSH thyrogen in the USA, can boost the uptakes to 50-60% allowing the therapy with iodine 131. The gland shrinks by 50-60%, but can cause hypothyroidism, and rarely pain syndrome cause by radiation thyroiditis that is short lived and treated by steroids.
# History
There are several findings that evidence a great interest for thyroid disorders just in the Medieval Medical School of Salerno (XII Century). Rogerius Salernitanus, the Salernitan surgeon and author of "Post mundi fabricam" (around 1180) was considered at that time the surgical text par excellence all over Europe. In the chapter "De bocio" of his magnus opum he describes several pharmacological and surgical cures, some of which nowadays are reappraised quite scientifically effective.
In modern times, the thyroid was first identified by the anatomist Thomas Wharton (whose name is also eponymised in Wharton's duct of the submandibular gland) in 1656.
Thyroid hormone (or thyroxin) was identified only in the 19th century.
# Additional images
- Section of the neck at about the level of the sixth cervical vertebra.
- Muscles of the neck. Anterior view.
- The arch of the aorta, and its branches.
- Superficial dissection of the right side of the neck, showing the carotid and subclavian arteries.
- Diagram showing common arrangement of thyroid veins.
- Sagittal section of nose mouth, pharynx, and larynx.
- Muscles of the pharynx, viewed from behind, together with the associated vessels and nerves.
- The position and relation of the esophagus in the cervical region and in the posterior mediastinum. Seen from behind.
- Section of thyroid gland of sheep. X 160.
- The thymus of a full-term fetus, exposed in situ.
- Thyoid histology | Thyroid
Template:Infobox Anatomy
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1] Phone:617-632-7753
The thyroid is one of the largest endocrine glands in the body. This gland is found in the neck inferior to (below) the mouth and at approximately the same level as the cricoid cartilage. The thyroid controls how quickly the body burns energy, makes proteins, and how sensitive the body should be to other hormones.
The thyroid participates in these processes by producing thyroid hormones, principally thyroxine (T4) and triiodothyronine (T3). These hormones regulate the rate of metabolism and affect the growth and rate of function of many other systems in the body. Iodine is an essential component of both T3 and T4. The thyroid also produces the hormone calcitonin, which plays a role in calcium homeostasis.
The thyroid is controlled by the hypothalamus and pituitary. The gland gets its name from the Greek word for "shield", after its shape, a double-lobed structure. Hyperthyroidism (overactive thyroid) and hypothyroidism (underactive thyroid) are the most common problems of the thyroid gland. Specialists are called thyroidologists.
# Anatomy
The thyroid is situated on the anterior side of the neck, starting at the oblique line on the thyroid cartilage (just below the laryngeal prominence or Adam's apple), and extending to the 6th Tracheal ring (C-shaped cartilagenous ring of the trachea). It is inappropriate to demarcate the gland's upper and lower border with vertebral levels as it moves position in relation to these during swallowing. It lies over the trachea and is covered by layers of pretracheal fascia (allowing it to move), muscle and skin.
The thyroid is one of the larger endocrine glands - 10-20 grams in adults - and butterfly-shaped. The wings correspond to the lobes and the body to the isthmus of the thyroid. The isthmus overlies tracheal rings 2, 3 and 4. The thyroid may enlarge substantially during pregnancy and when affected by a variety of diseases.
## Embryological development
In the fetus, at 3-4 weeks of gestation, the thyroid gland appears as an epithelial proliferation in the floor of the pharynx at the base of the tongue between the tuberculum impar and the copula linguae at a point latter indicated by the foramen cecum. Subsequently the thyroid descends in front of the pharyngeal gut as a bilobed diverticulum through the thyroglossal duct. Over the next few weeks, it migrates to the base of the neck. During migration, the thyroid remains connected to the tongue by a narrow canal, the thyroglossal duct.
Follicles of the thyroid begin to make colloid in the 11th week and thyroxine by the 18th week.
- Floor of pharynx of embryo between 18 and 21 days.
## Histology
At the microscopic level, there are three primary features of the thyroid:
# Physiology
The primary function of the thyroid is production of the hormones thyroxine (T4), triiodothyronine (T3), and calcitonin. Up to 80% of the T4 is converted to T3 by peripheral organs such as the liver, kidney and spleen. T3 is about ten times more active than T4.[1]
## T3 and T4 production and action
Thyroxine is synthesised by the follicular cells from free tyrosine and on the tyrosine residues of the protein called thyroglobulin (TG). Iodine is captured with the "iodine trap" by the hydrogen peroxide generated by the enzyme thyroid peroxidase (TPO)[2] and linked to the 3' and 5' sites of the benzene ring of the tyrosine residues on TG, and on free tyrosine. Upon stimulation by the thyroid-stimulating hormone (TSH), the follicular cells reabsorb TG and proteolytically cleave the iodinated tyrosines from TG, forming T4 and T3 (in T3, one iodine is absent compared to T4), and releasing them into the blood. Deiodinase enzymes convert T4 to T3.[3] Thyroid hormone that is secreted from the gland is about 90% T4 and about 10% T3.[1]
Cells of the brain are a major target for the thyroid hormones T3 and T4. Thyroid hormones play a particularly crucial role in brain development during pregnancy.[4] A transport protein (OATP1C1) has been identified that seems to be important for T4 transport across the blood brain barrier.[5] A second transport protein (MCT8) is important for T3 transport across brain cell membranes.[5]
In the blood, T4 and T3 are partially bound to thyroxine-binding globulin, transthyretin and albumin. Only a very small fraction of the circulating hormone is free (unbound) - T4 0.03% and T3 0.3%. Only the free fraction has hormonal activity. As with the steroid hormones and retinoic acid, thyroid hormones cross the cell membrane and bind to intracellular receptors (α1, α2, β1 and β2), which act alone, in pairs or together with the retinoid X-receptor as transcription factors to modulate DNA transcription[2].
## T3 and T4 regulation
The production of thyroxine and triiodothyronine is regulated by thyroid-stimulating hormone (TSH), released by the anterior pituitary. The thyroid and thyrotropes form a negative feedback loop: TSH production is suppressed when the T4 levels are high, and vice versa. The TSH production itself is modulated by thyrotropin-releasing hormone (TRH), which is produced by the hypothalamus and secreted at an increased rate in situations such as cold (in which an accelerated metabolism would generate more heat). TSH production is blunted by somatostatin (SRIH), rising levels of glucocorticoids and sex hormones (estrogen and testosterone), and excessively high blood iodide concentration.
## Calcitonin
An additional hormone produced by the thyroid contributes to the regulation of blood calcium levels. Parafollicular cells produce calcitonin in response to hypercalcemia. Calcitonin stimulates movement of calcium into bone, in opposition to the effects of parathyroid hormone (PTH). However, calcitonin seems far less essential than PTH, as calcium metabolism remains clinically normal after removal of the thyroid, but not the parathyroids.
It may be used diagnostically as a tumor marker for a form of thyroid cancer (medullary thyroid adenocarcinoma), in which high calcitonin levels may be present and elevated levels after surgery may indicate recurrence. It may even be used on biopsy samples from suspicious lesions (e.g. swollen lymph nodes) to establish whether they are metastasis of the original cancer.
Calcitonin can be used therapeutically for the treatment of hypercalcemia or osteoporosis.
## Significance of iodine
In areas of the world where iodine (essential for the production of thyroxine, which contains four iodine atoms) is lacking in the diet, the thyroid gland can be considerably enlarged, resulting in the swollen necks of endemic goitre.
Thyroxine is critical to the regulation of metabolism and growth throughout the animal kingdom. Among amphibians, for example, administering a thyroid-blocking agent such as propylthiouracil (PTU) can prevent tadpoles from metamorphosing into frogs; conversely, administering thyroxine will trigger metamorphosis.
In humans, children born with thyroid hormone deficiency will have physical growth and development problems, and brain development can also be severely impaired, in the condition referred to as cretinism. Newborn children in many developed countries are now routinely tested for thyroid hormone deficiency as part of newborn screening by analysis of a drop of blood. Children with thyroid hormone deficiency are treated by supplementation with synthetic thyroxine, which enables them to grow and develop normally.
Because of the thyroid's selective uptake and concentration of what is a fairly rare element, it is sensitive to the effects of various radioactive isotopes of iodine produced by nuclear fission. In the event of large accidental releases of such material into the environment, the uptake of radioactive iodine isotopes by the thyroid can, in theory, be blocked by saturating the uptake mechanism with a large surplus of non-radioactive iodine, taken in the form of potassium iodide tablets. While biological researchers making compounds labelled with iodine isotopes do this, in the wider world such preventive measures are usually not stockpiled before an accident, nor are they distributed adequately afterward. One consequence of the Chernobyl disaster was an increase in thyroid cancers in children in the years following the accident. [3]
The use of iodised salt is an efficient way to add iodine to the diet. It has eliminated endemic cretinism in most developed countries, and some governments have made the iodination of flour mandatory. Potassium iodide and Sodium iodide are the most active forms of supplemental iodine.
# Diseases
## Hyper- and hypofunction (affects about 2% of the population)
- Hypothyroidism (underactivity)
Hashimoto's thyroiditis / thyroiditis
Ord's thyroiditis
Postoperative hypothyroidism
Postpartum thyroiditis
Silent thyroiditis
Acute thyroiditis
Iatrogenic hypothyroidism
- Hashimoto's thyroiditis / thyroiditis
- Ord's thyroiditis
- Postoperative hypothyroidism
- Postpartum thyroiditis
- Silent thyroiditis
- Acute thyroiditis
- Iatrogenic hypothyroidism
- Hyperthyroidism (overactivity)
Thyroid storm
Graves-Basedow disease
Toxic thyroid nodule
Toxic nodular struma (Plummer's disease)
Hashitoxicosis
Iatrogenic hyperthyroidism
De Quervain thyroiditis (inflammation starting as hyperthyroidism, can end as hypothyroidism)
- Thyroid storm
- Graves-Basedow disease
- Toxic thyroid nodule
- Toxic nodular struma (Plummer's disease)
- Hashitoxicosis
- Iatrogenic hyperthyroidism
- De Quervain thyroiditis (inflammation starting as hyperthyroidism, can end as hypothyroidism)
## Anatomical problems
- Goitre
Endemic goitre
Diffuse goitre
Multinodular goitre
- Endemic goitre
- Diffuse goitre
- Multinodular goitre
- Lingual thyroid
- Thyroglossal duct cyst
## Tumors
- Thyroid adenoma
- Thyroid cancer
Papillary
Follicular
Medullary
Anaplastic
- Papillary
- Follicular
- Medullary
- Anaplastic
- Lymphomas and metastasis from elsewhere (rare)
## Deficiencies
- Cretinism
Medication linked to thyroid disease includes amiodarone, lithium salts, some types of interferon and IL-2.
# Diagnosis
## Blood tests
- The measurement of thyroid-stimulating hormone (TSH) levels is often used by doctors as a screening test. Elevated TSH levels can signify an inadequate hormone production, while suppressed levels can point at excessive unregulated production of hormone. This only applies to primary dysfunction, i.e. a disruption of the feedback loop at the site of the thyroid itself.
- If TSH is abnormal, decreased or increased levels of thyroid hormones T4 and T3 may be present; these may be determined to confirm this.
- In case of central (secondary or tertiary) thyroid dysfunction TSH concentrations may be normal despite pathological concentrations of T4 or T3.
- Autoantibodies may be detected in various disease states (anti-TG, anti-TPO, TSH receptor stimulating antibodies).
- There are two cancer markers for thyroid derived cancers. Thyroglobulin (TG) for well differentiated papillary or follcular adenocarcinoma, and the rare medullary thyroid cancer has calcitonin as the marker.
- Very infrequently, TBG and transthyretin levels may be abnormal; these are not routinely tested.
## Ultrasound
Nodules of the thyroid may or may not be cancer. Medical ultrasonography can help determine their nature because some of the characteristics of benign and malignant nodules differ. The main characteristics of a thyroid nodule on high frequency thyroid ultrasound are as follows:
Ultrasonography is not always able to separate benign from malignant nodules with complete certainty. In suspicious cases, a tissue sample is often obtained by biopsy for microscopic examination.
## Radioiodine scanning and uptake
Thyroid scintigraphy, imaging of the thyroid with the aid of radioactive iodine, usually iodine-123 (123I), is performed in the nuclear medicine department of a hospital or clinic. Radioiodine collects in the thyroid gland before being excreted in the urine. While in the thyroid the radioactive emissions can be detected by a camera, producing a rough image of the shape (a radiodine scan) and tissue activity (a radioiodine uptake) of the thyroid gland.
A normal radioiodine scan shows even uptake and activity throughout the gland. Irregularity can reflect an abnormally shaped or abnormally located gland, or it can indicate that a portion of the gland is overactive or underactive, different from the rest. For example, a nodule that is overactive ("hot") to the point of suppressing the activity of the rest of the gland is usually a thyrotoxic adenoma, a surgically curable form of hyperthyroidism that is hardly ever malignant. In contrast, finding that a substantial section of the thyroid is inactive ("cold") may indicate an area of non-functioning tissue such as thyroid cancer.
The amount of radioactivity can be counted as an indicator of the metabolic activity of the gland. A normal quantitation of radioiodine uptake demonstrates that about 8 to 35% of the administered dose can be detected in the thyroid 24 hours later. Overactivity or underactivity of the gland as may occur with hypothyroidism or hyperthyroidism is usually reflected in decreased or increased radioiodine uptake. Different patterns may occur with different causes of hypo- or hyperthyroidism.
## Biopsy
A medical biopsy refers to the obtaining of a tissue sample for examination under the microscope or other testing, usually to distinguish cancer from noncancerous conditions. Thyroid tissue may be obtained for biopsy by fine needle aspiration or by surgery.
Needle aspiration has the advantage of being a brief, safe, outpatient procedure that is safer and less expensive than surgery and does not leave a visible scar. Needle biopsies became widely used in the 1980s, but it was recognized that accuracy of identification of cancer was good but not perfect. The accuracy of the diagnosis depends on obtaining tissue from all of the suspicious areas of an abnormal thyroid gland. The reliability of needle aspiration is increased when sampling can be guided by ultrasound, and over the last 15 years, this has become the preferred method for thyroid biopsy in North America.
# Treatment
## Medical treatment
Levothyroxine is a stereoisomer of thyroxine which is degraded much slower and can be administered once daily in patients with hypothyroidism.
Graves' disease may be treated with the thioamide drugs propylthiouracil, carbimazole or methimazole, or rarely with Lugol's solution. Hyperthyroidism as well as thyroid tumors may be treated with radioactive iodine.
Percutaneous Ethanol Injections, PEI, for therapy of recurrent thyroid cysts, and metastatic thyroid cancer lymph nodes, as an alternative to the usual surgical method.
## Surgery
Thyroid surgery is performed for a variety of reasons. A nodule or lobe of the thyroid is sometimes removed for biopsy or for the presence of an autonomously functioning adenoma causing hyperthyroidism. A large majority of the thyroid may be removed, a subtotal thyroidectomy, to treat the hyperthyroidism of Graves' disease, or to remove a goitre that is unsightly or impinges on vital structures.
A complete thyroidectomy of the entire thyroid, including associated lymph nodes, is the preferred treatment for thyroid cancer. Removal of the bulk of the thyroid gland usually produces hypothyroidism, unless the person takes thyroid hormone replacement. Consequently, individuals who have undergone a total thyroidectomy are typically placed on thyroid hormone replacement for the remainder of their lives. Higher than normal doses are often administered to prevent recurrence.
If the thyroid gland must be removed surgically, care must be taken to avoid damage to adjacent structures, the parathyroid glands and the recurrent laryngeal nerve. Both are susceptible to accidental removal and/or injury during thyroid surgery. The parathyroid glands produce parathyroid hormone (PTH), a hormone needed to maintain adequate amounts of calcium in the blood. Removal results in hypoparathyroidism and a need for supplemental calcium and vitamin D each day. In the event the blood supply to any one of the parathyroid glands is endangered through surgery, the parathyroid gland(s) involved may be re-implanted in surrounding muscle tissue. The recurrent laryngeal nerves provide motor control for all external muscles of the larynx except for the cricothyroid muscle, also runs along the posterior thyroid. Accidental laceration of either of the two or both recurrent laryngeal nerves may cause paralysis of the vocal cords and their associated muscles, changing the voice quality.
## Radioiodine therapy
Large goiters that cause symptoms, but do not harbor cancer, after evaluation, and biopsy of suspicious nodules can be treated by an alternative therapy with radioiodine. The iodine uptake can be high in countries with iodine deficiency, but low in iodine sufficient countries. The 1999 release of rhTSH thyrogen in the USA, can boost the uptakes to 50-60% allowing the therapy with iodine 131. The gland shrinks by 50-60%, but can cause hypothyroidism, and rarely pain syndrome cause by radiation thyroiditis that is short lived and treated by steroids.
# History
There are several findings that evidence a great interest for thyroid disorders just in the Medieval Medical School of Salerno (XII Century). Rogerius Salernitanus, the Salernitan surgeon and author of "Post mundi fabricam" (around 1180) was considered at that time the surgical text par excellence all over Europe. In the chapter "De bocio" of his magnus opum he describes several pharmacological and surgical cures, some of which nowadays are reappraised quite scientifically effective.[6]
In modern times, the thyroid was first identified by the anatomist Thomas Wharton (whose name is also eponymised in Wharton's duct of the submandibular gland) in 1656.[7]
Thyroid hormone (or thyroxin) was identified only in the 19th century.
# Additional images
-
- Section of the neck at about the level of the sixth cervical vertebra.
- Muscles of the neck. Anterior view.
- The arch of the aorta, and its branches.
- Superficial dissection of the right side of the neck, showing the carotid and subclavian arteries.
- Diagram showing common arrangement of thyroid veins.
- Sagittal section of nose mouth, pharynx, and larynx.
- Muscles of the pharynx, viewed from behind, together with the associated vessels and nerves.
- The position and relation of the esophagus in the cervical region and in the posterior mediastinum. Seen from behind.
- Section of thyroid gland of sheep. X 160.
- The thymus of a full-term fetus, exposed in situ.
- Thyoid histology | https://www.wikidoc.org/index.php/Thyroid | |
b02f03bef547764429067d65d540e79aa9567f89 | wikidoc | Tobacco | Tobacco
# Overview
Tobacco is an agricultural product processed from the fresh leaves of plants in the genus Nicotiana.
Tobacco has been growing on the American Continent since about 6000 BC and began being used by native cultures at about 3000 BC. It has been smoked in one form or another since about 2000 BC. There are pictoral drawings of ancient Mayans smoking crude cigars from 1400 BC. Tobacco has a very long history of use in Native American culture and played an important part in the foundation of the United States of America, going back to colonial times and the original Jamestown settlement.
Commercially available dried, cured and natural forms, it is often smoked (see tobacco smoking) in the form of a cigar or cigarette, or in a stem pipe, water pipe, or hookah. Tobacco can also be chewed, "dipped" (placed between the cheek and gum), or sniffed into the nose as finely powdered snuff. Many countries set a minimum smoking age, regulating the purchase and use of tobacco products.
All methods of tobacco consumption results in varying quantities of nicotine being absorbed into the user's bloodstream. Over time, tolerance and dependence develop. Absorption quantity, frequency, and speed seem to have a direct relationship with how strong a dependence and tolerance, if any, might be created.
# Health effects
All means of tobacco consumption result in the absorption of nicotine, in varying amounts, into the user's bloodstream. A lethal dose of nicotine is contained in as little as one half of a cigar or three cigarettes. However, only a small fraction of the nicotine contained in these products is actually released into the smoke: most clinically significant cases of nicotine poisoning result from concentrated forms of the compound used as insecticides. Some sources report, however, that even a discarded cigarette butt can contain enough nicotine to kill a small child. Other active alkaloids in tobacco include harmala alkaloids.
Long-term tobacco use carries significant risks of developing various cancers as well as strokes and severe cardiovascular and respiratory diseases. Significantly shorter life expectancies have been associated with tobacco smoking. It has been shown that tobacco may cause lasting brain changes just like morphine or cocaine.
Many jurisdictions have enacted smoking bans in an effort to minimize possible damage to public health caused by tobacco smoking. The substantially increased risk of developing cancer as a result of tobacco usage seems to be due to the plethora of nitrosamines and other carcinogenic compounds found in tobacco and its residue as a result of anaerobic heating, either due to smoking or to flue-curing or fire-curing. The use of flue-cured or fire-cured smokeless tobacco in lieu of smoked tobacco reduces the risk of respiratory cancers but still carries significant risk of oral cancer. In contrast, use of steam-cured chewing tobacco (snus) avoids the carcinogenicity by not generating nitrosamines, though the negative effects of the nicotine on the cardiovascular system and pancreas are not ameliorated.
More than 400,000 Americans a year die from smoking: 276,000 men and 142,000 women.
One study from the Aristotle University of Thessaloniki in Greece measured the amount of naturally occurring radium and polonium found in Greece's tobacco leaves. The radiation dose was discovered to be nearly a thousand times more than the amount of Caesium-137 found in the leaves of plant life adjacent to the Chernobyl disaster. Despite the actual radiation dose attained by tobacco smokers being only 10 percent of the mean dose any person receives from the environment, some scientists believe that this radioactive content is a major cause of cancer deaths in smokers, and not nicotine or tar.
# Tobacco Use Disorder
## Epidemiology and Demographics
### Prevalence
The 12month prevalence of tobacco use disorder according to DSM IV criteria is 13,000 per 100,000 (13%) among ages 18 years and older.
## Risk Factors
- Anxiety disorder
- Attention-deficit/hyperactivity disorder
- Bipolar disorder
- Conduct disorder
- Depressive disorder
- Externalizing personality traits
- Genetic predisposition
- Individuals with low incomes
- Low educational levels
- Other substance use disorders
- Personality disorder
- Psychotic disorder
## Diagnostic Criteria
## DSM-V Diagnostic Criteria for Tobacco Use Disorder
# Tobacco Withdrawal
## Differential Diagnosis
- Anxiety disorder
- Alcohol withdrawal
- Bipolar disorder
- Caffeine withdrawal
- Caffeine intoxication
- Depressive disorder
- Medication-induced akathisia
- Opioid withdrawal
- Sedative, hypnotic, or anxiolytic withdrawal
- Stimulant withdrawal
- Sleep disorder
- Voluntary smoking cessation
## Epidemiology and Demographics
### Prevalence
The prevalence of tobacco withdrawal is 50,000 per 100,000 (50%) of the overall population.
## Risk Factors
- Attention-deficit/hyperactivity disorder
- Anxiety disorders
- Bipolar disorders
- Genetic predisposition
- Other substance use disorders
- Smokers with depressive disorders
## Diagnostic Criteria
## DSM-V Diagnostic Criteria for Tobacco Withdrawal | Tobacco
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Kiran Singh, M.D. [2]
# Overview
Tobacco is an agricultural product processed from the fresh leaves of plants in the genus Nicotiana.
Tobacco has been growing on the American Continent since about 6000 BC and began being used by native cultures at about 3000 BC. It has been smoked in one form or another since about 2000 BC. There are pictoral drawings of ancient Mayans smoking crude cigars from 1400 BC. Tobacco has a very long history of use in Native American culture and played an important part in the foundation of the United States of America, going back to colonial times and the original Jamestown settlement.
Commercially available dried, cured and natural forms, it is often smoked (see tobacco smoking) in the form of a cigar or cigarette, or in a stem pipe, water pipe, or hookah. Tobacco can also be chewed, "dipped" (placed between the cheek and gum), or sniffed into the nose as finely powdered snuff. Many countries set a minimum smoking age, regulating the purchase and use of tobacco products.
All methods of tobacco consumption results in varying quantities of nicotine being absorbed into the user's bloodstream. Over time, tolerance and dependence develop. Absorption quantity, frequency, and speed seem to have a direct relationship with how strong a dependence and tolerance, if any, might be created.
# Health effects
All means of tobacco consumption result in the absorption of nicotine, in varying amounts, into the user's bloodstream. A lethal dose of nicotine is contained in as little as one half of a cigar or three cigarettes. However, only a small fraction of the nicotine contained in these products is actually released into the smoke: most clinically significant cases of nicotine poisoning result from concentrated forms of the compound used as insecticides. Some sources report, however, that even a discarded cigarette butt can contain enough nicotine to kill a small child.[1] Other active alkaloids in tobacco include harmala alkaloids.
Long-term tobacco use carries significant risks of developing various cancers as well as strokes and severe cardiovascular and respiratory diseases.[2] Significantly shorter life expectancies have been associated with tobacco smoking.[3] It has been shown that tobacco may cause lasting brain changes just like morphine or cocaine.[4]
Many jurisdictions have enacted smoking bans in an effort to minimize possible damage to public health caused by tobacco smoking. The substantially increased risk of developing cancer as a result of tobacco usage seems to be due to the plethora of nitrosamines and other carcinogenic compounds found in tobacco and its residue as a result of anaerobic heating, either due to smoking or to flue-curing or fire-curing. The use of flue-cured or fire-cured smokeless tobacco in lieu of smoked tobacco reduces the risk of respiratory cancers but still carries significant risk of oral cancer.[5] In contrast, use of steam-cured chewing tobacco (snus) avoids the carcinogenicity by not generating nitrosamines, though the negative effects of the nicotine on the cardiovascular system and pancreas are not ameliorated.[6]
More than 400,000 Americans a year die from smoking: 276,000 men and 142,000 women.[7]
One study from the Aristotle University of Thessaloniki in Greece measured the amount of naturally occurring radium and polonium found in Greece's tobacco leaves. The radiation dose was discovered to be nearly a thousand times more than the amount of Caesium-137 found in the leaves of plant life adjacent to the Chernobyl disaster. Despite the actual radiation dose attained by tobacco smokers being only 10 percent of the mean dose any person receives from the environment, some scientists believe that this radioactive content is a major cause of cancer deaths in smokers, and not nicotine or tar.[8]
# Tobacco Use Disorder
## Epidemiology and Demographics
### Prevalence
The 12month prevalence of tobacco use disorder according to DSM IV criteria is 13,000 per 100,000 (13%) among ages 18 years and older.[9]
## Risk Factors
- Anxiety disorder
- Attention-deficit/hyperactivity disorder
- Bipolar disorder
- Conduct disorder
- Depressive disorder
- Externalizing personality traits
- Genetic predisposition
- Individuals with low incomes
- Low educational levels
- Other substance use disorders
- Personality disorder
- Psychotic disorder[9]
## Diagnostic Criteria
## DSM-V Diagnostic Criteria for Tobacco Use Disorder[9]
# Tobacco Withdrawal
## Differential Diagnosis
- Anxiety disorder
- Alcohol withdrawal
- Bipolar disorder
- Caffeine withdrawal
- Caffeine intoxication
- Depressive disorder
- Medication-induced akathisia
- Opioid withdrawal
- Sedative, hypnotic, or anxiolytic withdrawal
- Stimulant withdrawal
- Sleep disorder
- Voluntary smoking cessation[9]
## Epidemiology and Demographics
### Prevalence
The prevalence of tobacco withdrawal is 50,000 per 100,000 (50%) of the overall population.[9]
## Risk Factors
- Attention-deficit/hyperactivity disorder
- Anxiety disorders
- Bipolar disorders
- Genetic predisposition
- Other substance use disorders
- Smokers with depressive disorders
## Diagnostic Criteria
## DSM-V Diagnostic Criteria for Tobacco Withdrawal[9] | https://www.wikidoc.org/index.php/Tobacco | |
9cc0962e6fffac9bd509bfa8b4bac8f4cffcbfe6 | wikidoc | Toddler | Toddler
Toddler is a common term for a young child who is learning to walk or "toddle", generally considered to be the second stage of development after infancy and before childhood occurring predominantly during the ages of 12 to 36 months old. During this period, the child learns a great deal about social roles and develops motor skills; to toddle is to walk unsteadily. The term cruising is used for toddlers who cannot toddle but must hold onto something while walking.
The toddler developmental timeline shows what an average toddler can do at what age. Times vary greatly from child to child. It is common for some toddlers to master certain skills (such as walking) well before other skills (like talking). Even close siblings can vary greatly in the time taken to achieve each key milestone.
This age is sometimes referred to as 'the terrible twos', because of the temper tantrums for which they are famous. This stage can begin as early as nine months old depending on the child and environment. The toddler is discovering that they are a separate being from their mother or caregiver and are testing their boundaries in learning the way the world around them works. This time between the ages of two and five when they are reaching for independence repeats itself during adolescence. Thus it is very important for the caregiver to be consistent with boundaries and discipline for the child’s safety and the caregiver's sanity through puberty.
Most children are toilet trained while they are toddlers. In most Western countries, toilet training starts as early as 17 months for some while others are not ready to begin toilet training until they are three.
When toddlers can walk they are still often transported in a buggy, or stroller when they are tired, or to increase speed.
Around 18 months, the toddler's vocabulary will greatly increase, and he or she may learn as many as 7-9 new words a day.
# Overview table | Toddler
Toddler is a common term for a young child who is learning to walk or "toddle",[1] generally considered to be the second stage of development after infancy and before childhood occurring predominantly during the ages of 12 to 36 months old.[2] During this period, the child learns a great deal about social roles and develops motor skills; to toddle is to walk unsteadily. The term cruising is used for toddlers who cannot toddle but must hold onto something while walking.
The toddler developmental timeline shows what an average toddler can do at what age. Times vary greatly from child to child. It is common for some toddlers to master certain skills (such as walking) well before other skills (like talking). Even close siblings can vary greatly in the time taken to achieve each key milestone.
This age is sometimes referred to as 'the terrible twos', because of the temper tantrums for which they are famous. This stage can begin as early as nine months old depending on the child and environment. The toddler is discovering that they are a separate being from their mother or caregiver and are testing their boundaries in learning the way the world around them works. This time between the ages of two and five when they are reaching for independence repeats itself during adolescence. Thus it is very important for the caregiver to be consistent with boundaries and discipline for the child’s safety and the caregiver's sanity through puberty.
Most children are toilet trained while they are toddlers. In most Western countries, toilet training starts as early as 17 months for some while others are not ready to begin toilet training until they are three.
When toddlers can walk they are still often transported in a buggy, or stroller when they are tired, or to increase speed.
Around 18 months, the toddler's vocabulary will greatly increase, and he or she may learn as many as 7-9 new words a day.
# Overview table | https://www.wikidoc.org/index.php/Toddler | |
a3333d3bf77eb53b308be38d540ea04c88b2856d | wikidoc | Toluene | Toluene
# Overview
Toluene, also known as methylbenzene or phenylmethane, is a clear, water-insoluble liquid with the typical smell of paint thinners, redolent of the sweet smell of the related compound benzene. It is an aromatic hydrocarbon that is widely used as an industrial feedstock and as a solvent.
# History
The name toluene was derived from the older name toluol that refers to tolu balsam, an aromatic extract from the tropical Colombian tree Myroxylon balsamum, from which it was first isolated. It was originally named by Jöns Jakob Berzelius.
# Chemical properties
Toluene reacts as a normal aromatic hydrocarbon towards electrophilic aromatic substitution. The methyl group makes it around 25 times more reactive than benzene in such reactions. It undergoes smooth sulfonation to give p-toluenesulfonic acid, and chlorination by Cl2 in the presence of FeCl3 to give ortho and para isomers of chlorotoluene. It undergoes nitration to give ortho and para nitrotoluene isomers, but if heated it can give dinitrotoluene and ultimately the explosive trinitrotoluene (TNT).
With other reagents the methyl side chain in toluene may react, undergoing oxidation. Reaction with potassium permanganate leads to benzoic acid, whereas reaction with chromyl chloride leads to benzaldehyde (Étard reaction). Halogenation can be performed under free radical conditions. For example, N-bromosuccinimide (NBS) heated with toluene in the presence of AIBN leads to benzyl bromide.
Catalytic hydrogenation of toluene to methylcyclohexane requires a high pressure of hydrogen to go to completion, because of the stability of the aromatic system.
pka is approximately 45.
# Preparation
Toluene occurs naturally at low levels in crude oil and is usually produced in the processes of making gasoline via a catalytic reformer, in an ethylene cracker or making coke from coal. Final separation (either via distillation or solvent extraction) takes place in a BTX plant.
# Uses
Toluene is a common solvent, able to dissolve: paints, paint thinners, many chemical reactants, rubber, printing ink, adhesives (glues), lacquers, leather tanners, and disinfectants. It can also be used as a fullerene indicator, and is a raw material for toluene diisocyanate (used in the manufacture of polyurethane foam) and TNT. Industrial uses of toluene include dealkylation to benzene and disproportionation to a mixture of benzene and xylene. When oxidized it yields benzaldehyde and benzoic acid, two important intermediates in chemistry. It is also used as a carbon source for making Multi-Wall Carbon Nanotubes. Toluene can be used to break open red blood cells in order to extract hemoglobin in biochemistry experiments.
Toluene can be used as an octane booster in gasoline fuels used in internal combustion engines. Toluene at 84% by volume, fueled all the turbo Formula 1 teams in the 1980s.
# Toxicology and metabolism
Inhalation of toluene fumes can be intoxicating, but in larger doses nausea-inducing. Toluene may enter the human system not only through vapour inhalation from the liquid evaporation, but also following soil contamination events, where human contact with soil, ingestion of contaminated groundwater or soil vapour off-gassing can occur.
The toxicity of toluene can be explained mostly by its metabolism. As toluene has very low water solubility, it cannot exit the body via the normal routes (urine, feces, or sweat). It must be metabolized in order to be excreted. The methyl group of toluene is more easily oxidized by cytochrome P450 than the benzene ring. Therefore, in the metabolism of toluene, 95% is oxidized to become benzyl alcohol. The toxic metabolites are created by the remaining 5% that are oxidized to benzaldehyde and cresols. Most of the reactive products are detoxified by conjugation to glutathione but the remainder may severely damage cells.
Toluene is mainly excreted as benzoic acid and hippuric acid, both formed by further metabolic oxidation of benzyl alcohol. | Toluene
Template:Chembox new
# Overview
Toluene, also known as methylbenzene or phenylmethane, is a clear, water-insoluble liquid with the typical smell of paint thinners, redolent of the sweet smell of the related compound benzene. It is an aromatic hydrocarbon that is widely used as an industrial feedstock and as a solvent.
# History
The name toluene was derived from the older name toluol that refers to tolu balsam, an aromatic extract from the tropical Colombian tree Myroxylon balsamum, from which it was first isolated. It was originally named by Jöns Jakob Berzelius.
# Chemical properties
Toluene reacts as a normal aromatic hydrocarbon towards electrophilic aromatic substitution.[1][2][3] The methyl group makes it around 25 times more reactive than benzene in such reactions. It undergoes smooth sulfonation to give p-toluenesulfonic acid, and chlorination by Cl2 in the presence of FeCl3 to give ortho and para isomers of chlorotoluene. It undergoes nitration to give ortho and para nitrotoluene isomers, but if heated it can give dinitrotoluene and ultimately the explosive trinitrotoluene (TNT).
With other reagents the methyl side chain in toluene may react, undergoing oxidation. Reaction with potassium permanganate leads to benzoic acid, whereas reaction with chromyl chloride leads to benzaldehyde (Étard reaction). Halogenation can be performed under free radical conditions. For example, N-bromosuccinimide (NBS) heated with toluene in the presence of AIBN leads to benzyl bromide.
Catalytic hydrogenation of toluene to methylcyclohexane requires a high pressure of hydrogen to go to completion, because of the stability of the aromatic system.
pka is approximately 45.
# Preparation
Toluene occurs naturally at low levels in crude oil and is usually produced in the processes of making gasoline via a catalytic reformer, in an ethylene cracker or making coke from coal. Final separation (either via distillation or solvent extraction) takes place in a BTX plant.
# Uses
Toluene is a common solvent, able to dissolve: paints, paint thinners, many chemical reactants, rubber, printing ink, adhesives (glues), lacquers, leather tanners, and disinfectants. It can also be used as a fullerene indicator, and is a raw material for toluene diisocyanate (used in the manufacture of polyurethane foam) and TNT. Industrial uses of toluene include dealkylation to benzene and disproportionation to a mixture of benzene and xylene. When oxidized it yields benzaldehyde and benzoic acid, two important intermediates in chemistry. It is also used as a carbon source for making Multi-Wall Carbon Nanotubes. Toluene can be used to break open red blood cells in order to extract hemoglobin in biochemistry experiments.
Toluene can be used as an octane booster in gasoline fuels used in internal combustion engines. Toluene at 84% by volume, fueled all the turbo Formula 1 teams in the 1980s.
# Toxicology and metabolism
Inhalation of toluene fumes can be intoxicating, but in larger doses nausea-inducing. Toluene may enter the human system not only through vapour inhalation from the liquid evaporation, but also following soil contamination events, where human contact with soil, ingestion of contaminated groundwater or soil vapour off-gassing can occur.
The toxicity of toluene can be explained mostly by its metabolism. As toluene has very low water solubility, it cannot exit the body via the normal routes (urine, feces, or sweat). It must be metabolized in order to be excreted. The methyl group of toluene is more easily oxidized by cytochrome P450 than the benzene ring. Therefore, in the metabolism of toluene, 95% is oxidized to become benzyl alcohol.[4] The toxic metabolites are created by the remaining 5% that are oxidized to benzaldehyde and cresols.[5][6] Most of the reactive products are detoxified by conjugation to glutathione but the remainder may severely damage cells.[7]
Toluene is mainly excreted as benzoic acid and hippuric acid, both formed by further metabolic oxidation of benzyl alcohol. | https://www.wikidoc.org/index.php/Toluene | |
42b902badfae3755a8e5d47e0e896f7f804b473f | wikidoc | Tomacco | Tomacco
Tomacco is originally a fictional hybrid fruit that is half tomato and half tobacco, from the 1999 episode "E-I-E-I-(Annoyed Grunt)" of The Simpsons; the method used to create the tomacco in the episode is fictional. The tomacco became real when it was produced in 2003. The tomacco is one of the few made-up words in The Simpsons that resulted in real life application.
# Fictional tomacco
In the Simpsons' episode, the tomacco was accidentally created by Homer Simpson when he "planted a little bit of everything" and fertilized his tomato and tobacco fields with plutonium. The result is a tomato that apparently has a dried, gray tobacco center, and, although being described as tasting terrible by many characters (Ralph Wiggum: "Eww, Daddy, this tastes like Grandma!" Clancy Wiggum: "My god, it DOES taste like Grandma!"), is also immediately and powerfully addictive. The creation is promptly labeled "Tomacco" by Homer and sold in large quantities to unsuspecting passers by. Laramie cigarettes, seeing an opportunity to sell their products to children legally, offers to buy the rights to market tomacco for $150 million. Homer refuses, demanding $150 billion instead. This offer is rejected by the company's executives. The hybrid plant is so powerfully addictive that farm animals develop the abilities of speech and bipedal locomotion in their frenzied quest to gain more tomacco. A cow kicks through the wall of the Simpson farmhouse and screams a rudimentary "TOMACCO!" when looking for more. Eventually, all but one of the tomacco plants are eaten by farm animals. The company executives manage to steal the last tomacco plant as they depart, but a tomacco-crazed sheep attacks them, causing their helicopter to crash, destroying the last remaining plant. The sheep was somehow able to survive the crash.
# Real tomacco
In 2003, inspired by The Simpsons, Rob Baur of Lake Oswego, Oregon successfully grafted a tomato plant onto the roots of a tobacco plant. This was possible because both plants come from the same family, Solanaceae or nightshade, and furthermore both plants are dicotyledons (it is not possible to graft monocotyledons, because the xylem and the phloem are distributed in bundles throughout the stem, and therefore it is impossible to align the vascular tissues of the two plants).
The plant produced fruit that looked like a normal tomato, but Baur suspected that it contained a lethal amount of nicotine and thus would be inedible. Testing later proved that the leaves of the plant contained some nicotine. The world's first tomacco fruit, destroyed in the testing process, contained no nicotine. The second tomacco fruit was given to a Simpsons writer. The third was sold on eBay and the fourth was eaten by a Xerox engineer who suffered no apparent ill effects from the fruit. The Tomacco plant bore fruit until it died due to weather-related causes at the ripe age of 18 months, having spent the previous winter indoors.
The process of making tomacco was first revealed in a 1959 Scientific American article, which stated that nicotine could be found in the tomato plant after grafting. Due to the academic and industrial importance of this breakthrough process, this article was reprinted in a 1968 Scientific American compilation, Bio-Organic Chemistry, on page 170. (ISBN 0-7167-0974-0)
The 2004 convention of the American Dialect Society named tomacco as the new word "least likely to succeed." Tomacco was www.wordspy.com "word of the Day". | Tomacco
Tomacco is originally a fictional hybrid fruit that is half tomato and half tobacco, from the 1999 episode "E-I-E-I-(Annoyed Grunt)" of The Simpsons; the method used to create the tomacco in the episode is fictional. The tomacco became real when it was produced in 2003. The tomacco is one of the few made-up words in The Simpsons that resulted in real life application.
# Fictional tomacco
In the Simpsons' episode, the tomacco was accidentally created by Homer Simpson when he "planted a little bit of everything" and fertilized his tomato and tobacco fields with plutonium. The result is a tomato that apparently has a dried, gray tobacco center, and, although being described as tasting terrible by many characters (Ralph Wiggum: "Eww, Daddy, this tastes like Grandma!" Clancy Wiggum: "My god, it DOES taste like Grandma!"), is also immediately and powerfully addictive. The creation is promptly labeled "Tomacco" by Homer and sold in large quantities to unsuspecting passers by. Laramie cigarettes, seeing an opportunity to sell their products to children legally, offers to buy the rights to market tomacco for $150 million. Homer refuses, demanding $150 billion instead. This offer is rejected by the company's executives. The hybrid plant is so powerfully addictive that farm animals develop the abilities of speech and bipedal locomotion in their frenzied quest to gain more tomacco. A cow kicks through the wall of the Simpson farmhouse and screams a rudimentary "TOMACCO!" when looking for more. Eventually, all but one of the tomacco plants are eaten by farm animals. The company executives manage to steal the last tomacco plant as they depart, but a tomacco-crazed sheep attacks them, causing their helicopter to crash, destroying the last remaining plant. The sheep was somehow able to survive the crash.
# Real tomacco
In 2003, inspired by The Simpsons, Rob Baur of Lake Oswego, Oregon successfully grafted a tomato plant onto the roots of a tobacco plant. This was possible because both plants come from the same family, Solanaceae or nightshade, and furthermore both plants are dicotyledons (it is not possible to graft monocotyledons, because the xylem and the phloem are distributed in bundles throughout the stem, and therefore it is impossible to align the vascular tissues of the two plants).
The plant produced fruit that looked like a normal tomato, but Baur suspected that it contained a lethal amount of nicotine and thus would be inedible. Testing later proved that the leaves of the plant contained some nicotine. The world's first tomacco fruit, destroyed in the testing process, contained no nicotine. The second tomacco fruit was given to a Simpsons writer. The third was sold on eBay and the fourth was eaten by a Xerox engineer who suffered no apparent ill effects from the fruit. The Tomacco plant bore fruit until it died due to weather-related causes at the ripe age of 18 months, having spent the previous winter indoors.
The process of making tomacco was first revealed in a 1959 Scientific American article, which stated that nicotine could be found in the tomato plant after grafting. Due to the academic and industrial importance of this breakthrough process, this article was reprinted in a 1968 Scientific American compilation, Bio-Organic Chemistry, on page 170. (ISBN 0-7167-0974-0)
The 2004 convention of the American Dialect Society named tomacco as the new word "least likely to succeed."[1] Tomacco was www.wordspy.com "word of the Day". http://www.wordspy.com/words/tomacco.asp
# External links
- The Simpsons Archive: "E-I-E-I-(ANNOYED GRUNT)"
- Wired News: Simpsons Plant Seeds of Invention
- Simpsons Fan Grows Tomacco
- [2]
de:Tomacco
no:Tomacco
Template:WikiDoc Sources | https://www.wikidoc.org/index.php/Tomacco | |
5d732b5ec0913ef7f6fc0b93efcd4086e4ec7260 | wikidoc | Topical | Topical
In medicine, a topical medication is applied to body surfaces such as the skin or mucous membranes, for example the vagina, penis, throat, eyes and ears.
Some hydrophobic chemicals such as steroid hormones can be absorbed into the body after being applied to the skin in the form of a cream, gel or lotion. Transdermal patches have become a popular means of administering some drugs for birth control, hormone replacement therapy, and prevention of motion sickness.
In dentistry, a topical medication may also mean one that is applied to the surface of teeth.
Chloramphenicol is an example of an antibiotic that may be used topically. | Topical
In medicine, a topical medication is applied to body surfaces such as the skin or mucous membranes, for example the vagina, penis, throat, eyes and ears.
Some hydrophobic chemicals such as steroid hormones can be absorbed into the body after being applied to the skin in the form of a cream, gel or lotion. Transdermal patches have become a popular means of administering some drugs for birth control, hormone replacement therapy, and prevention of motion sickness.
In dentistry, a topical medication may also mean one that is applied to the surface of teeth.
Chloramphenicol is an example of an antibiotic that may be used topically. | https://www.wikidoc.org/index.php/Topical | |
758840d660e7268c4149dcb0624fee09d3a39d2c | wikidoc | Triadin | Triadin
Triadin, also known as TRDN, is a human gene associated with the release of calcium ions from the sarcoplasmic reticulum triggering muscular contraction through calcium-induced calcium release. Triadin is a multiprotein family, arising from different processing of the TRDN gene on chromosome 6. It is a transmembrane protein on the sarcoplasmic reticulum due to a well defined hydrophobic section and it forms a quaternary complex with the cardiac ryanodine receptor (RYR2), calsequestrin (CASQ2) and junctin proteins. The luminal (inner compartment of the sarcoplasmic reticulum) section of Triadin has areas of highly charged amino acid residues that act as luminal Ca2+ receptors. Triadin is also able to sense luminal Ca2+ concentrations by mediating interactions between RYR2 and CASQ2. Triadin has several different forms; Trisk 95 and Trisk 51, which are expressed in skeletal muscle, and Trisk 32 (CT1), which is mainly expressed in cardiac muscle.
# Interactions
TRDN has been shown to interact with RYR1.
Triadin is required to physically link the RYR2 and CASQ2 proteins, so that RYR2 channel activity can be regulated by CASQ2. The linkage of RYR2 with CASQ2 occurs via highly charged luminal sections of Triadin that are characterized as alternating positively and negatively charged amino acids, known as the KEKE motif.
Luminal concentration levels of Ca2+ are sensed by CSQ, and this information is transmitted to RyR via Triadin. At low luminal Ca2+ concentrations, Triadin is bound to both RYR2 and CASQ2, so that CSQ prevents RYR2 from opening. At high luminal Ca2+ concentrations, Ca2+ binding sites on CASQ2 become occupied with Ca2+, leading to a weakened interaction between CASQ2 and Triadin. This removes CASQ2’s ability to have an inhibitory effect on the RYR2 channel activity. As more Ca2+ binding sites on CASQ2 become occupied, there is an increasing probability of the RYR2 channel being able to open. Eventually, CASQ2 completely dissociates from Triadin and the RYR2 channel becomes completely uninhibited, although Triadin remains bound to RYR2 at all luminal concentrations of Ca2+.
# Relation to catecholaminergic polymorphic ventricular tachycardia
Most mutations that result in CPVT are found in RYR2 or CASQ2 genes, however a third of CPVT patients have no mutations in either of these proteins, making a mutation in Triadin the most likely cause Because Triadin is necessary in the regulation of Ca2+ release by the RyR channel during cardiac contraction, a mutation that prevents Triadin from being formed will make CASQ2 unable to inhibit the RYR2 channel activity, allowing Ca2+ leaks and the development of CPVT.
A deletion of amino acids in the TRDN gene can result in an early stop codon. A premature stop codon can either prevent the gene from being translated into the Triadin protein, or can result in a shortened, nonfunctional Triadin protein. A replacement of the amino acid Arginine for the amino acid Threonine at position 59 of the TRDN gene (pT59R) causes instability of Triadin, leading to degradation of the protein. Any of these naturally occurring mutations result in an absence of functional Triadin protein, resulting in CPVT in patients. | Triadin
Triadin, also known as TRDN, is a human gene[1] associated with the release of calcium ions from the sarcoplasmic reticulum triggering muscular contraction through calcium-induced calcium release. Triadin is a multiprotein family, arising from different processing of the TRDN gene on chromosome 6.[2] It is a transmembrane protein on the sarcoplasmic reticulum due to a well defined hydrophobic section[3][4] and it forms a quaternary complex with the cardiac ryanodine receptor (RYR2), calsequestrin (CASQ2) and junctin proteins.[3][4][5][6] The luminal (inner compartment of the sarcoplasmic reticulum) section of Triadin has areas of highly charged amino acid residues that act as luminal Ca2+ receptors.[3][4][6] Triadin is also able to sense luminal Ca2+ concentrations by mediating interactions between RYR2 and CASQ2.[5] Triadin has several different forms; Trisk 95 and Trisk 51, which are expressed in skeletal muscle, and Trisk 32 (CT1), which is mainly expressed in cardiac muscle.[7]
# Interactions
TRDN has been shown to interact with RYR1.[8][9][10][11]
Triadin is required to physically link the RYR2 and CASQ2 proteins, so that RYR2 channel activity can be regulated by CASQ2.[12] The linkage of RYR2 with CASQ2 occurs via highly charged luminal sections of Triadin[6] that are characterized as alternating positively and negatively charged amino acids, known as the KEKE motif.[4][5][6][13]
Luminal concentration levels of Ca2+ are sensed by CSQ, and this information is transmitted to RyR via Triadin. At low luminal Ca2+ concentrations, Triadin is bound to both RYR2 and CASQ2, so that CSQ prevents RYR2 from opening. At high luminal Ca2+ concentrations, Ca2+ binding sites on CASQ2 become occupied with Ca2+, leading to a weakened interaction between CASQ2 and Triadin. This removes CASQ2’s ability to have an inhibitory effect on the RYR2 channel activity. As more Ca2+ binding sites on CASQ2 become occupied, there is an increasing probability of the RYR2 channel being able to open. Eventually, CASQ2 completely dissociates from Triadin and the RYR2 channel becomes completely uninhibited, although Triadin remains bound to RYR2 at all luminal concentrations of Ca2+.[12]
# Relation to catecholaminergic polymorphic ventricular tachycardia
Most mutations that result in CPVT are found in RYR2 or CASQ2 genes, however a third of CPVT patients have no mutations in either of these proteins, making a mutation in Triadin the most likely cause[14] Because Triadin is necessary in the regulation of Ca2+ release by the RyR channel during cardiac contraction, a mutation that prevents Triadin from being formed will make CASQ2 unable to inhibit the RYR2 channel activity, allowing Ca2+ leaks and the development of CPVT.[14]
A deletion of amino acids in the TRDN gene can result in an early stop codon.[14] A premature stop codon can either prevent the gene from being translated into the Triadin protein, or can result in a shortened, nonfunctional Triadin protein.[14] A replacement of the amino acid Arginine for the amino acid Threonine at position 59 of the TRDN gene (pT59R) causes instability of Triadin, leading to degradation of the protein.[14] Any of these naturally occurring mutations result in an absence of functional Triadin protein, resulting in CPVT in patients.[14] | https://www.wikidoc.org/index.php/Triadin | |
dcf39b73f27815cfdb3988368bc471812341b0b9 | wikidoc | TrimSpa | TrimSpa
TrimSpa is a dietary supplement designed for weight loss, marketed by the company Goen Technologies, headed by Alex Goen. Celebrity Anna Nicole Smith was its spokesperson. Various products marketed by TrimSpa are claimed to help "stave off hunger". TrimSpa formerly contained ephedra until that ingredient was banned in the U.S.. The new TrimSpa formula X32 contains no ephedra. Its active ingredient is Hoodia gordonii, along with the stimulants caffeine and theobromine.
# Composition
Hoodia is a succulent native to Africa which is currently under investigation for use as an appetite suppressant. However, it has not been conclusively demonstrated that Hoodia works as an appetite suppressant in humans. No published peer-reviewed double-blind clinical trials have been performed on humans to investigate the safety or effectiveness of Hoodia gordonii in pill form as a nutritional supplement.
In addition to Hoodia gordonii, TrimSpa X32 tablets contain ingredients that may help promote weight loss, including green tea, glucomannan, cocoa extract, vanadium, and glucosamine. According to the manufacturer's labeling, TrimSpa X32 pills are taken 3 times per day minimum, 6 maximum.
TrimSpa X32 also contains chromium. Chromium may be beneficial in glucose regulation. The stimulant components are hoodia gordonii and components containing caffeine (green tea and cocoa extracts).
TrimSpa expanded its weight-loss aids in 2006 to include a fruit-based bar, FROODIA, containing 400 mg of African Hoodia gordonii.
# Federal Trade Commission fine for false claims
On January 4, 2007 the U.S. Federal Trade Commission announced that the marketers of TrimSpa had agreed to pay a settlement of $1.5 million in response to an FTC complaint of making unsupported claims in advertisements, and were also prohibited "from making any claims about the health benefits, performance, efficacy, safety, or side effects of TrimSpa, Hoodia gordonii, or any dietary supplement, food, drug, or health-related service or program, unless the claims are true, not misleading, and substantiated by competent and reliable scientific evidence." The FTC also announced similar settlements with the marketers of Xenadrine EFX, CortiSlim, and One-A-Day WeightSmart.
# Over-the-counter disclaimer
TrimSpa is considered an herbal supplement, and therefore, the U.S. Food and Drug Administration (FDA) does not currently regulate it. As such, the dietary supplement manufacturer is responsible for ensuring that TrimSpa is safe before it is marketed. Hence, TrimSpa's safety and effectiveness have not been reviewed by the FDA.
# Celebrity Endorsements
The model Anna Nicole Smith made TrimSpa famous in commercials with the phrase "TrimSpa, Baby!". Following her death, there has been speculation in the media about the company's future. | TrimSpa
TrimSpa is a dietary supplement designed for weight loss, marketed by the company Goen Technologies, headed by Alex Goen. Celebrity Anna Nicole Smith was its spokesperson. Various products marketed by TrimSpa are claimed to help "stave off hunger".[1] TrimSpa formerly contained ephedra until that ingredient was banned in the U.S.. The new TrimSpa formula X32 contains no ephedra. Its active ingredient is Hoodia gordonii, along with the stimulants caffeine and theobromine.
# Composition
Hoodia is a succulent native to Africa which is currently under investigation for use as an appetite suppressant. However, it has not been conclusively demonstrated that Hoodia works as an appetite suppressant in humans. No published peer-reviewed double-blind clinical trials have been performed on humans to investigate the safety or effectiveness of Hoodia gordonii in pill form as a nutritional supplement.
In addition to Hoodia gordonii, TrimSpa X32 tablets contain ingredients that may help promote weight loss, including green tea, glucomannan, cocoa extract, vanadium, and glucosamine.[2] According to the manufacturer's labeling, TrimSpa X32 pills are taken 3 times per day minimum, 6 maximum.[2]
TrimSpa X32 also contains chromium.[2] Chromium may be beneficial in glucose regulation.[3] The stimulant components are hoodia gordonii and components containing caffeine (green tea and cocoa extracts).
TrimSpa expanded its weight-loss aids in 2006 to include a fruit-based bar, FROODIA, containing 400 mg of African Hoodia gordonii.
# Federal Trade Commission fine for false claims
On January 4, 2007 the U.S. Federal Trade Commission announced that the marketers of TrimSpa had agreed to pay a settlement of $1.5 million in response to an FTC complaint of making unsupported claims in advertisements, and were also prohibited "from making any claims about the health benefits, performance, efficacy, safety, or side effects of TrimSpa, Hoodia gordonii, or any dietary supplement, food, drug, or health-related service or program, unless the claims are true, not misleading, and substantiated by competent and reliable scientific evidence." The FTC also announced similar settlements with the marketers of Xenadrine EFX, CortiSlim, and One-A-Day WeightSmart.[4]
# Over-the-counter disclaimer
TrimSpa is considered an herbal supplement, and therefore, the U.S. Food and Drug Administration (FDA) does not currently regulate it.[5] As such, the dietary supplement manufacturer is responsible for ensuring that TrimSpa is safe before it is marketed. Hence, TrimSpa's safety and effectiveness have not been reviewed by the FDA.
# Celebrity Endorsements
The model Anna Nicole Smith made TrimSpa famous in commercials with the phrase "TrimSpa, Baby!". Following her death, there has been speculation in the media about the company's future. [1] | https://www.wikidoc.org/index.php/TrimSpa | |
dfef80c8d655ee1632fee510b35438cae3fcbd77 | wikidoc | Tritium | Tritium
Tritium (pronunciation TRIT-ee-um, symbol T or ³H) is a radioactive isotope of hydrogen. The nucleus of tritium (sometimes called a triton) contains one proton and two neutrons, whereas the nucleus of protium (the most abundant hydrogen isotope) contains no neutrons.
# Decay
Tritium is radioactive with a half-life of 12.32 years. It decays into helium-3 by the reaction
releasing 18.6 keV of energy. The electron has an average kinetic energy of 5.7 keV, while the remaining energy is carried off by the nearly undetectable electron antineutrino. The low-energy beta radiation from tritium cannot penetrate human skin, so tritium is only dangerous if inhaled or ingested. Its low energy also creates difficulty detecting tritium labelled compounds except by using liquid scintillation counting.
# Production
Tritium occurs naturally due to cosmic rays interacting with atmospheric gases. In the most important reaction for natural tritium production, a fast neutron (> 4MeV ) interacts with atmospheric nitrogen:
Because of tritium's relatively short half-life, however, tritium produced in this manner does not accumulate over geological timescales, and its natural abundance is negligible.
Tritium is produced in nuclear reactors by neutron activation of lithium-6. This is possible with neutrons of any energy, and is an exothermic reaction yielding 4.8 MeV, which is more than one-quarter of the energy that fusion of the produced triton with a deuteron can later produce.
High-energy neutrons can also produce tritium from lithium-7 in an endothermic reaction, consuming 2.822 MeV. This was discovered when the 1954 Castle Bravo nuclear test produced an unexpectedly high yield.
High-energy neutrons irradiating boron-10 will also occasionally produce tritium. The more common result of boron-10 neutron capture is 7Li and a single alpha particle.
The reactions requiring high neutron energies are not attractive production methods.
Tritium's decay product helium-3 has a very large cross section for the (n,p) reaction with thermal neutrons and is rapidly converted back to tritium in a nuclear reactor.
Tritium is occasionally a direct product of nuclear fission, with a yield of about 0.01% (one per 10000 fissions). This means that tritium release or recovery needs to be considered in nuclear reprocessing even in ordinary spent nuclear fuel where tritium production was not a goal.
Tritium is also produced in heavy water-moderated reactors when deuterium captures a neutron. This reaction has a very small cross section (which is why heavy water is such a good neutron moderator) and relatively little tritium is produced; nevertheless, cleaning tritium from the moderator may be desirable after several years to reduce the risk of escape to the environment. Ontario Power Generation's Tritium Removal Facility can process up to 2.5 thousand tonnes (2,500 Mg) of heavy water a year, producing about 2.5 kg of tritium.
According to IEER's 1996 report about the United States Department of Energy, only 225 kg of tritium has been produced in the US since 1955. Since it is continuously decaying into helium-3, the stockpile was approximately, 75 kg at the time of the report.
Tritium for American nuclear weapons was produced in special heavy water reactors at the Savannah River Site until their shutdown in 1988; with the Strategic Arms Reduction Treaty after the end of the Cold War, existing supplies were sufficient for the new, smaller number of nuclear weapons for some time. Production was resumed with irradiation of lithium-containing rods (replacing the usual boron-containing control rods) at the commercial Watts Bar Nuclear Generating Station in 2003-2005 followed by extraction of tritium from the rods at the new Tritium Extraction Facility at SRS starting in November 2006.
# Properties
Tritium has an atomic mass of 3.0160492. It is a gas (T2 or ³H2) at standard temperature and pressure. Tritium combines with oxygen to form a liquid called tritiated water T2O or partially tritiated THO.
Tritium figures prominently in studies of nuclear fusion due to its favorable reaction cross section and the high energy yield of 17.6 MeV for its reaction with deuterium:
All atomic nuclei, being composed of protons and neutrons, repel one another because of their positive charge. However, if the atoms have a high enough temperature and pressure (as is the case in the core of the Sun, for example), then their random motions can overcome such electrical repulsion (called the Coulomb force), and they can come close enough for the strong nuclear force to take effect, fusing them into heavier atoms. Since tritium has the same charge as ordinary hydrogen, it experiences the same electrostatic repulsive force (see Coulomb's law). However, due to tritium's supply of neutrons which are carried into reactions and feel the attractive strong force once delivered, tritium can more easily fuse with other light atoms. The same is also true, albeit to a lesser extent, of deuterium, and that is why brown dwarfs (so-called failed stars) cannot burn hydrogen, but do indeed burn deuterium.
Before the onset of atmospheric nuclear weapons tests, the global equilibrium tritium inventory was estimated at about 80 megacuries (MCi).
Like hydrogen, tritium is difficult to confine; rubber, plastic, and some kinds of steel are all somewhat permeable. This has raised concerns that if tritium is used in quantity, in particular for fusion reactors, it may contribute to radioactive contamination, although its short half-life should prevent any significant accumulation in the atmosphere.
Atmospheric nuclear testing (prior to the Partial Test Ban Treaty) proved unexpectedly useful to oceanographers, as the sharp spike in surface tritium levels could be used over the years to measure the rate at which the lower and upper ocean levels mixed.
# Regulatory limits
The legal limits for tritium in drinking water can vary. The U.S. limit is calculated to yield a dose of 4 mrem (or 40 microsieverts in SI units) per year.
- Canada 7,000 Bq/L.
- United States 740 Bq/L or 20,000 pCi/L (Safe Drinking Water Act)
- World Health Organization 1,000 Bq/L.
# Usage
## Self-powered lighting
The emitted electrons from small amounts of tritium cause phosphors to glow so as to make self-powered lighting devices called trasers which are now used in watches and exit signs. It is also used in certain countries to make glowing keychains, and compasses. In recent years, the same process has been used to make self-illuminating gun sights for firearms. These take the place of radium, which can cause bone cancer. These uses of radium have been banned in most countries for decades.
The aforementioned IEER report claims that the commercial demand for tritium is 400 grams per year.
## Nuclear weapons
Tritium is widely used in nuclear weapons for boosting a fission bomb or the fission primary of a thermonuclear weapon. Before detonation, a few grams of tritium-deuterium gas are injected into the hollow "pit" of fissile plutonium or uranium. The early stages of the fission chain reaction supply enough heat and compression to start DT fusion, then both fission and fusion proceed in parallel, the fission assisting the fusion by continuing heating and compression, and the fusion assisting the fission with highly energetic (14.1 MeV) neutrons. As the fission fuel depletes and also explodes outward, it falls below the density needed to stay critical by itself, but the fusion neutrons make the fission process progress faster and continue longer than it would without boosting. Increased yield comes overwhelmingly from the increase in fission; the energy released by the fusion itself is much smaller because the amount of fusion fuel is much smaller.
Besides increased yield (for the same amount of fission fuel with vs. without boosting) and the possibility of variable yield (by varying the amount of fusion fuel), possibly even more important advantages are allowing the weapon (or primary of a weapon) to have a smaller amount of fissile material (eliminating the risk of predetonation by nearby nuclear explosions) and more relaxed requirements for implosion, allowing a smaller implosion system.
Because the tritium in the warhead is continuously decaying, it is necessary to replenish it periodically. The estimated quantity needed is 4 grams per warhead. To maintain constant inventory, 0.22 grams per warhead per year must be produced.
As tritium quickly decays and is difficult to contain, the much larger secondary charge of a thermonuclear weapon instead uses lithium deuteride as its fusion fuel; during detonation, neutrons split lithium-6 into helium-4 and tritium; the tritium then fuses with deuterium, producing more neutrons. As this process requires a higher temperature for ignition, and produces fewer and less energetic neutrons (only D-D fusion and 7Li splitting are net neutron producers), LiD is not used for boosting, only for secondaries.
## Controlled nuclear fusion
Tritium is an important fuel for controlled nuclear fusion in both magnetic confinement and inertial confinement fusion reactor designs. The experimental fusion reactor ITER and the National Ignition Facility (NIF) will use Deuterium-Tritium (D-T) fuel. The D-T reaction is favored since it has the largest fusion cross-section (~ 5 barns peak) and reaches this maximum cross-section at the lowest energy (~65 keV center-of-mass) of any potential fusion fuel.
# History
Tritium was first predicted in the late 1920s by Walter Russell, using his "spiral" periodic table, then produced in 1934 from deuterium, another isotope of hydrogen, by Ernest Rutherford, working with Mark Oliphant and Paul Harteck. Rutherford was unable to isolate the tritium, a job that was left to Luis Alvarez and Robert Cornog, who correctly deduced that the substance was radioactive. Willard F. Libby discovered that tritium could be used for dating water, and therefore wine. | Tritium
Template:Infobox isotope
Tritium (pronunciation TRIT-ee-um, symbol T or ³H) is a radioactive isotope of hydrogen. The nucleus of tritium (sometimes called a triton) contains one proton and two neutrons, whereas the nucleus of protium (the most abundant hydrogen isotope) contains no neutrons.
# Decay
Tritium is radioactive with a half-life of 12.32 years. It decays into helium-3 by the reaction
releasing 18.6 keV of energy. The electron has an average kinetic energy of 5.7 keV, while the remaining energy is carried off by the nearly undetectable electron antineutrino. The low-energy beta radiation from tritium cannot penetrate human skin, so tritium is only dangerous if inhaled or ingested. Its low energy also creates difficulty detecting tritium labelled compounds except by using liquid scintillation counting.
# Production
Tritium occurs naturally due to cosmic rays interacting with atmospheric gases. In the most important reaction for natural tritium production, a fast neutron (> 4MeV [1]) interacts with atmospheric nitrogen:
Because of tritium's relatively short half-life, however, tritium produced in this manner does not accumulate over geological timescales, and its natural abundance is negligible.
Tritium is produced in nuclear reactors by neutron activation of lithium-6. This is possible with neutrons of any energy, and is an exothermic reaction yielding 4.8 MeV, which is more than one-quarter of the energy that fusion of the produced triton with a deuteron can later produce.
High-energy neutrons can also produce tritium from lithium-7 in an endothermic reaction, consuming 2.822 MeV. This was discovered when the 1954 Castle Bravo nuclear test produced an unexpectedly high yield.[2]
High-energy neutrons irradiating boron-10 will also occasionally produce tritium. [3]The more common result of boron-10 neutron capture is 7Li and a single alpha particle.[4]
The reactions requiring high neutron energies are not attractive production methods.
Tritium's decay product helium-3 has a very large cross section for the (n,p) reaction with thermal neutrons and is rapidly converted back to tritium in a nuclear reactor.
Tritium is occasionally a direct product of nuclear fission, with a yield of about 0.01% (one per 10000 fissions).[5][6] This means that tritium release or recovery needs to be considered in nuclear reprocessing even in ordinary spent nuclear fuel where tritium production was not a goal.
Tritium is also produced in heavy water-moderated reactors when deuterium captures a neutron. This reaction has a very small cross section (which is why heavy water is such a good neutron moderator) and relatively little tritium is produced; nevertheless, cleaning tritium from the moderator may be desirable after several years to reduce the risk of escape to the environment. Ontario Power Generation's Tritium Removal Facility can process up to 2.5 thousand tonnes (2,500 Mg) of heavy water a year, producing about 2.5 kg of tritium. [7]
According to IEER's 1996 report about the United States Department of Energy, only 225 kg of tritium has been produced in the US since 1955. Since it is continuously decaying into helium-3, the stockpile was approximately, 75 kg at the time of the report.[8]
Tritium for American nuclear weapons was produced in special heavy water reactors at the Savannah River Site until their shutdown in 1988; with the Strategic Arms Reduction Treaty after the end of the Cold War, existing supplies were sufficient for the new, smaller number of nuclear weapons for some time. Production was resumed with irradiation of lithium-containing rods (replacing the usual boron-containing control rods) at the commercial Watts Bar Nuclear Generating Station in 2003-2005 followed by extraction of tritium from the rods at the new Tritium Extraction Facility at SRS starting in November 2006.[9]
# Properties
Tritium has an atomic mass of 3.0160492. It is a gas (T2 or ³H2) at standard temperature and pressure. Tritium combines with oxygen to form a liquid called tritiated water T2O or partially tritiated THO.
Tritium figures prominently in studies of nuclear fusion due to its favorable reaction cross section and the high energy yield of 17.6 MeV for its reaction with deuterium:
All atomic nuclei, being composed of protons and neutrons, repel one another because of their positive charge. However, if the atoms have a high enough temperature and pressure (as is the case in the core of the Sun, for example), then their random motions can overcome such electrical repulsion (called the Coulomb force), and they can come close enough for the strong nuclear force to take effect, fusing them into heavier atoms. Since tritium has the same charge as ordinary hydrogen, it experiences the same electrostatic repulsive force (see Coulomb's law). However, due to tritium's supply of neutrons which are carried into reactions and feel the attractive strong force once delivered, tritium can more easily fuse with other light atoms. The same is also true, albeit to a lesser extent, of deuterium, and that is why brown dwarfs (so-called failed stars) cannot burn hydrogen, but do indeed burn deuterium.
Before the onset of atmospheric nuclear weapons tests, the global equilibrium tritium inventory was estimated at about 80 megacuries (MCi).
Like hydrogen, tritium is difficult to confine; rubber, plastic, and some kinds of steel are all somewhat permeable. This has raised concerns that if tritium is used in quantity, in particular for fusion reactors, it may contribute to radioactive contamination, although its short half-life should prevent any significant accumulation in the atmosphere.
Atmospheric nuclear testing (prior to the Partial Test Ban Treaty) proved unexpectedly useful to oceanographers, as the sharp spike in surface tritium levels could be used over the years to measure the rate at which the lower and upper ocean levels mixed.
# Regulatory limits
The legal limits for tritium in drinking water can vary. The U.S. limit is calculated to yield a dose of 4 mrem (or 40 microsieverts in SI units) per year.
- Canada 7,000 Bq/L.
- United States 740 Bq/L or 20,000 pCi/L (Safe Drinking Water Act)
- World Health Organization 1,000 Bq/L.
# Usage
## Self-powered lighting
The emitted electrons from small amounts of tritium cause phosphors to glow so as to make self-powered lighting devices called trasers which are now used in watches and exit signs. It is also used in certain countries to make glowing keychains, and compasses. In recent years, the same process has been used to make self-illuminating gun sights for firearms. These take the place of radium, which can cause bone cancer. These uses of radium have been banned in most countries for decades.
The aforementioned IEER report claims that the commercial demand for tritium is 400 grams per year.
## Nuclear weapons
Tritium is widely used in nuclear weapons for boosting a fission bomb or the fission primary of a thermonuclear weapon. Before detonation, a few grams of tritium-deuterium gas are injected into the hollow "pit" of fissile plutonium or uranium. The early stages of the fission chain reaction supply enough heat and compression to start DT fusion, then both fission and fusion proceed in parallel, the fission assisting the fusion by continuing heating and compression, and the fusion assisting the fission with highly energetic (14.1 MeV) neutrons. As the fission fuel depletes and also explodes outward, it falls below the density needed to stay critical by itself, but the fusion neutrons make the fission process progress faster and continue longer than it would without boosting. Increased yield comes overwhelmingly from the increase in fission; the energy released by the fusion itself is much smaller because the amount of fusion fuel is much smaller.
Besides increased yield (for the same amount of fission fuel with vs. without boosting) and the possibility of variable yield (by varying the amount of fusion fuel), possibly even more important advantages are allowing the weapon (or primary of a weapon) to have a smaller amount of fissile material (eliminating the risk of predetonation by nearby nuclear explosions) and more relaxed requirements for implosion, allowing a smaller implosion system.
Because the tritium in the warhead is continuously decaying, it is necessary to replenish it periodically. The estimated quantity needed is 4 grams per warhead.[10] To maintain constant inventory, 0.22 grams per warhead per year must be produced.
As tritium quickly decays and is difficult to contain, the much larger secondary charge of a thermonuclear weapon instead uses lithium deuteride as its fusion fuel; during detonation, neutrons split lithium-6 into helium-4 and tritium; the tritium then fuses with deuterium, producing more neutrons. As this process requires a higher temperature for ignition, and produces fewer and less energetic neutrons (only D-D fusion and 7Li splitting are net neutron producers), LiD is not used for boosting, only for secondaries.
## Controlled nuclear fusion
Tritium is an important fuel for controlled nuclear fusion in both magnetic confinement and inertial confinement fusion reactor designs. The experimental fusion reactor ITER and the National Ignition Facility (NIF) will use Deuterium-Tritium (D-T) fuel. The D-T reaction is favored since it has the largest fusion cross-section (~ 5 barns peak) and reaches this maximum cross-section at the lowest energy (~65 keV center-of-mass) of any potential fusion fuel.
# History
Tritium was first predicted in the late 1920s by Walter Russell, using his "spiral" periodic table[citation needed], then produced in 1934 from deuterium, another isotope of hydrogen, by Ernest Rutherford, working with Mark Oliphant and Paul Harteck. Rutherford was unable to isolate the tritium, a job that was left to Luis Alvarez and Robert Cornog, who correctly deduced that the substance was radioactive. Willard F. Libby discovered that tritium could be used for dating water, and therefore wine. | https://www.wikidoc.org/index.php/Tritium | |
d739bcba4b9f3776dc2d05143791d51f6ce3fc16 | wikidoc | Trypsin | Trypsin
Trypsin (EC 3.4.21.4) is a serine protease from the PA clan superfamily, found in the digestive system of many vertebrates, where it hydrolyzes proteins. Trypsin is formed in the small intestine when its proenzyme form, the trypsinogen produced by the pancreas, is activated. Trypsin cleaves peptide chains mainly at the carboxyl side of the amino acids lysine or arginine, except when either is followed by proline. It is used for numerous biotechnological processes. The process is commonly referred to as trypsin proteolysis or trypsinisation, and proteins that have been digested/treated with trypsin are said to have been trypsinized. Trypsin was discovered in 1876 by Wilhelm Kühne.
# Function
In the duodenum, trypsin catalyzes the hydrolysis of peptide bonds, breaking down proteins into smaller peptides. The peptide products are then further hydrolyzed into amino acids via other proteases, rendering them available for absorption into the blood stream. Tryptic digestion is a necessary step in protein absorption, as proteins are generally too large to be absorbed through the lining of the small intestine.
Trypsin is produced as the inactive zymogen trypsinogen in the pancreas. When the pancreas is stimulated by cholecystokinin, it is then secreted into the first part of the small intestine (the duodenum) via the pancreatic duct. Once in the small intestine, the enzyme enteropeptidase activates trypsinogen into trypsin by proteolytic cleavage. Autocatalysis does not happen with trypsin, as trypsinogen is a poor substrate, therefore enzymatic damage to the pancreas is avoided.
# Mechanism
The enzymatic mechanism is similar to that of other serine proteases. These enzymes contain a catalytic triad consisting of histidine-57, aspartate-102, and serine-195. This catalytic triad was formerly called a charge relay system, implying the abstraction of protons from serine to histidine and from histidine to aspartate, but owing to evidence provided by NMR that the resultant alkoxide form of serine would have a much stronger pull on the proton than does the imidazole ring of histidine, current thinking holds instead that serine and histidine each have effectively equal share of the proton, forming short low-barrier hydrogen bonds therewith. By these means, the nucleophilicity of the active site serine is increased, facilitating its attack on the amide carbon during proteolysis. The enzymatic reaction that trypsin catalyzes is thermodynamically favorable, but requires significant activation energy (it is "kinetically unfavorable"). In addition, trypsin contains an "oxyanion hole" formed by the backbone amide hydrogen atoms of Gly-193 and Ser-195, which through hydrogen bonding stabilize the negative charge which accumulates on the amide oxygen after nucleophilic attack on the planar amide carbon by the serine oxygen causes that carbon to assume a tetrahedral geometry. Such stabilisation of this tetrahedral intermediate helps to reduce the energy barrier of its formation and is concomitant with a lowering of the free energy of the transition state. Preferential binding of the transition state is a key feature of enzyme chemistry.
The aspartate residue (Asp 189) located in the catalytic pocket (S1) of trypsin is responsible for attracting and stabilizing positively charged lysine and/or arginine, and is, thus, responsible for the specificity of the enzyme. This means that trypsin predominantly cleaves proteins at the carboxyl side (or "C-terminal side") of the amino acids lysine and arginine except when either is bound to a C-terminal proline, although large-scale mass spectrometry data suggest cleavage occurs even with proline. Trypsin is considered an endopeptidase, i.e., the cleavage occurs within the polypeptide chain rather than at the terminal amino acids located at the ends of polypeptides.
# Properties
Human trypsin has an optimal operating temperature of about 37 °C. In contrast, the Atlantic cod has several types of trypsins for the poikilotherm fish to survive at different body temperatures. Cod trypsins include trypsin I with an activity range of 4 to 65 °C (40 to 150 °F) and maximal activity at 55 °C (130 °F), as well as trypsin Y with a range of 2 to 30 °C (36 to 86 °F) and a maximal activity at 21 °C (70 °F).
As a protein, trypsin has various molecular weights depending on the source. For example, a molecular weight of 23.3 kDa is reported for trypsin from bovine and porcine sources.
The activity of trypsin is not affected by the enzyme inhibitor tosyl phenylalanyl chloromethyl ketone, TPCK, which deactivates chymotrypsin. This is important because, in some applications, like mass spectrometry, the specificity of cleavage is important.
Trypsin should be stored at very cold temperatures (between −20 and −80 °C) to prevent autolysis, which may also be impeded by storage of trypsin at pH 3 or by using trypsin modified by reductive methylation. When the pH is adjusted back to pH 8, activity returns.
# Isozymes
These human genes encode proteins with trypsin enzymatic activity:
Other isoforms of trypsin may also be found in other organisms.
# Clinical significance
Activation of trypsin from proteolytic cleavage of trypsinogen in the pancreas can lead to a series of events that cause pancreatic self-digestion, resulting in pancreatitis. One consequence of the autosomal recessive disease cystic fibrosis is a deficiency in transport of trypsin and other digestive enzymes from the pancreas. This leads to the disorder termed meconium ileus, which involves intestinal obstruction (ileus) due to overly thick meconium, which is normally broken down by trypsin and other proteases, then passed in feces.
# Applications
Trypsin is available in high quantity in pancreases, and can be purified rather easily. Hence, it has been used widely in various biotechnological processes.
In a tissue culture lab, trypsin is used to resuspend cells adherent to the cell culture dish wall during the process of harvesting cells. Some cell types adhere to the sides and bottom of a dish when cultivated in vitro. Trypsin is used to cleave proteins holding the cultured cells to the dish, so that the cells can be removed from the plates.
Trypsin can also be used to dissociate dissected cells (for example, prior to cell fixing and sorting).
Trypsin can be used to break down casein in breast milk. If trypsin is added to a solution of milk powder, the breakdown of casein causes the milk to become translucent. The rate of reaction can be measured by using the amount of time needed for the milk to turn translucent.
Trypsin is commonly used in biological research during proteomics experiments to digest proteins into peptides for mass spectrometry analysis, e.g. in-gel digestion. Trypsin is particularly suited for this, since it has a very well defined specificity, as it hydrolyzes only the peptide bonds in which the carbonyl group is contributed either by an arginine or lysine residue.
Trypsin can also be used to dissolve blood clots in its microbial form and treat inflammation in its pancreatic form.
## In food
Commercial protease preparations usually consist of a mixture of various protease enzymes that often includes trypsin. These preparations are widely used in food processing:
- as a baking enzyme to improve the workability of dough
- in the extraction of seasonings and flavorings from vegetable or animal proteins and in the manufacture of sauces
- to control aroma formation in cheese and milk products
- to improve the texture of fish products
- to tenderize meat
- during cold stabilization of beer
- in the production of hypoallergenic food where proteases break down specific allergenic proteins into nonallergenic peptides, for example, proteases are used to produce hypoallergenic baby food from cow's milk, thereby diminishing the risk of babies developing milk allergies.
# Trypsin inhibitor
To prevent the action of active trypsin in the pancreas, which can be highly damaging, inhibitors such as BPTI and SPINK1 in the pancreas and α1-antitrypsin in the serum are present as part of the defense against its inappropriate activation. Any trypsin prematurely formed from the inactive trypsinogen is then bound by the inhibitor. The protein-protein interaction between trypsin and its inhibitors is one of the tightest bound, and trypsin is bound by some of its pancreatic inhibitors nearly irreversibly. In contrast with nearly all known protein assemblies, some complexes of trypsin bound by its inhibitors do not readily dissociate after treatment with 8M urea. | Trypsin
Trypsin (EC 3.4.21.4) is a serine protease from the PA clan superfamily, found in the digestive system of many vertebrates, where it hydrolyzes proteins.[2][3] Trypsin is formed in the small intestine when its proenzyme form, the trypsinogen produced by the pancreas, is activated. Trypsin cleaves peptide chains mainly at the carboxyl side of the amino acids lysine or arginine, except when either is followed by proline. It is used for numerous biotechnological processes. The process is commonly referred to as trypsin proteolysis or trypsinisation, and proteins that have been digested/treated with trypsin are said to have been trypsinized.[4] Trypsin was discovered in 1876 by Wilhelm Kühne.[5]
# Function
In the duodenum, trypsin catalyzes the hydrolysis of peptide bonds, breaking down proteins into smaller peptides. The peptide products are then further hydrolyzed into amino acids via other proteases, rendering them available for absorption into the blood stream. Tryptic digestion is a necessary step in protein absorption, as proteins are generally too large to be absorbed through the lining of the small intestine.[6]
Trypsin is produced as the inactive zymogen trypsinogen in the pancreas. When the pancreas is stimulated by cholecystokinin, it is then secreted into the first part of the small intestine (the duodenum) via the pancreatic duct. Once in the small intestine, the enzyme enteropeptidase activates trypsinogen into trypsin by proteolytic cleavage. Autocatalysis does not happen with trypsin, as trypsinogen is a poor substrate, therefore enzymatic damage to the pancreas is avoided.[6]
# Mechanism
The enzymatic mechanism is similar to that of other serine proteases. These enzymes contain a catalytic triad consisting of histidine-57, aspartate-102, and serine-195.[7] This catalytic triad was formerly called a charge relay system, implying the abstraction of protons from serine to histidine and from histidine to aspartate, but owing to evidence provided by NMR that the resultant alkoxide form of serine would have a much stronger pull on the proton than does the imidazole ring of histidine, current thinking holds instead that serine and histidine each have effectively equal share of the proton, forming short low-barrier hydrogen bonds therewith.[8] By these means, the nucleophilicity of the active site serine is increased, facilitating its attack on the amide carbon during proteolysis. The enzymatic reaction that trypsin catalyzes is thermodynamically favorable, but requires significant activation energy (it is "kinetically unfavorable"). In addition, trypsin contains an "oxyanion hole" formed by the backbone amide hydrogen atoms of Gly-193 and Ser-195, which through hydrogen bonding stabilize the negative charge which accumulates on the amide oxygen after nucleophilic attack on the planar amide carbon by the serine oxygen causes that carbon to assume a tetrahedral geometry. Such stabilisation of this tetrahedral intermediate helps to reduce the energy barrier of its formation and is concomitant with a lowering of the free energy of the transition state. Preferential binding of the transition state is a key feature of enzyme chemistry.
The aspartate residue (Asp 189) located in the catalytic pocket (S1) of trypsin is responsible for attracting and stabilizing positively charged lysine and/or arginine, and is, thus, responsible for the specificity of the enzyme. This means that trypsin predominantly cleaves proteins at the carboxyl side (or "C-terminal side") of the amino acids lysine and arginine except when either is bound to a C-terminal proline,[9] although large-scale mass spectrometry data suggest cleavage occurs even with proline.[10] Trypsin is considered an endopeptidase, i.e., the cleavage occurs within the polypeptide chain rather than at the terminal amino acids located at the ends of polypeptides.
# Properties
Human trypsin has an optimal operating temperature of about 37 °C.[11] In contrast, the Atlantic cod has several types of trypsins for the poikilotherm fish to survive at different body temperatures. Cod trypsins include trypsin I with an activity range of 4 to 65 °C (40 to 150 °F) and maximal activity at 55 °C (130 °F), as well as trypsin Y with a range of 2 to 30 °C (36 to 86 °F) and a maximal activity at 21 °C (70 °F).[12]
As a protein, trypsin has various molecular weights depending on the source. For example, a molecular weight of 23.3 kDa is reported for trypsin from bovine and porcine sources.
The activity of trypsin is not affected by the enzyme inhibitor tosyl phenylalanyl chloromethyl ketone, TPCK, which deactivates chymotrypsin. This is important because, in some applications, like mass spectrometry, the specificity of cleavage is important.
Trypsin should be stored at very cold temperatures (between −20 and −80 °C) to prevent autolysis, which may also be impeded by storage of trypsin at pH 3 or by using trypsin modified by reductive methylation. When the pH is adjusted back to pH 8, activity returns.
# Isozymes
These human genes encode proteins with trypsin enzymatic activity:
Other isoforms of trypsin may also be found in other organisms.
# Clinical significance
Activation of trypsin from proteolytic cleavage of trypsinogen in the pancreas can lead to a series of events that cause pancreatic self-digestion, resulting in pancreatitis. One consequence of the autosomal recessive disease cystic fibrosis is a deficiency in transport of trypsin and other digestive enzymes from the pancreas. This leads to the disorder termed meconium ileus, which involves intestinal obstruction (ileus) due to overly thick meconium, which is normally broken down by trypsin and other proteases, then passed in feces.[13]
# Applications
Trypsin is available in high quantity in pancreases, and can be purified rather easily. Hence, it has been used widely in various biotechnological processes.
In a tissue culture lab, trypsin is used to resuspend cells adherent to the cell culture dish wall during the process of harvesting cells.[14] Some cell types adhere to the sides and bottom of a dish when cultivated in vitro. Trypsin is used to cleave proteins holding the cultured cells to the dish, so that the cells can be removed from the plates.
Trypsin can also be used to dissociate dissected cells (for example, prior to cell fixing and sorting).
Trypsin can be used to break down casein in breast milk. If trypsin is added to a solution of milk powder, the breakdown of casein causes the milk to become translucent. The rate of reaction can be measured by using the amount of time needed for the milk to turn translucent.
Trypsin is commonly used in biological research during proteomics experiments to digest proteins into peptides for mass spectrometry analysis, e.g. in-gel digestion. Trypsin is particularly suited for this, since it has a very well defined specificity, as it hydrolyzes only the peptide bonds in which the carbonyl group is contributed either by an arginine or lysine residue.
Trypsin can also be used to dissolve blood clots in its microbial form and treat inflammation in its pancreatic form.
## In food
Commercial protease preparations usually consist of a mixture of various protease enzymes that often includes trypsin. These preparations are widely used in food processing:[15]
- as a baking enzyme to improve the workability of dough
- in the extraction of seasonings and flavorings from vegetable or animal proteins and in the manufacture of sauces
- to control aroma formation in cheese and milk products
- to improve the texture of fish products
- to tenderize meat
- during cold stabilization of beer
- in the production of hypoallergenic food where proteases break down specific allergenic proteins into nonallergenic peptides, for example, proteases are used to produce hypoallergenic baby food from cow's milk, thereby diminishing the risk of babies developing milk allergies.
# Trypsin inhibitor
To prevent the action of active trypsin in the pancreas, which can be highly damaging, inhibitors such as BPTI and SPINK1 in the pancreas and α1-antitrypsin in the serum are present as part of the defense against its inappropriate activation. Any trypsin prematurely formed from the inactive trypsinogen is then bound by the inhibitor. The protein-protein interaction between trypsin and its inhibitors is one of the tightest bound, and trypsin is bound by some of its pancreatic inhibitors nearly irreversibly.[16] In contrast with nearly all known protein assemblies, some complexes of trypsin bound by its inhibitors do not readily dissociate after treatment with 8M urea.[17] | https://www.wikidoc.org/index.php/Trypsin | |
840fabaf707fbf1179be710fc1655c2c22c3eaa3 | wikidoc | Tuftsin | Tuftsin
Tuftsin is a tetrapeptide (Thr-Lys-Pro-Arg) produced by enzymatic cleavage of the Fc-domain of the heavy chain of immunoglobulin G. It is produced primarily in the spleen.
# Function
Its biological activity is related primarily to the immune system function.
Tuftsin binds to specific receptors on the surface of macrophages and polymorphonuclear leukocytes, stimulating their migration, phagocytic, bactericidal, and tumoricidal activity. It also influences antibody formation.
# Pathology
Tuftsin deficiency, either hereditary or following splenectomy, results in increased susceptibility to certain infections.
# Clinical significance
Tuftsin has been chemically synthesized and it is considered for use in immunotherapy.
# History
Tuftsin was first identified in 1970 by scientists Najjar and Nishioka. It was named after Tufts University where the peptide was discovered. | Tuftsin
Template:Chembox new
Tuftsin is a tetrapeptide (Thr-Lys-Pro-Arg) produced by enzymatic cleavage of the Fc-domain of the heavy chain of immunoglobulin G. It is produced primarily in the spleen.
# Function
Its biological activity is related primarily to the immune system function.
Tuftsin binds to specific receptors on the surface of macrophages and polymorphonuclear leukocytes, stimulating their migration, phagocytic, bactericidal, and tumoricidal activity. It also influences antibody formation.
# Pathology
Tuftsin deficiency, either hereditary or following splenectomy, results in increased susceptibility to certain infections. [1]
# Clinical significance
Tuftsin has been chemically synthesized and it is considered for use in immunotherapy.
# History
Tuftsin was first identified in 1970 by scientists Najjar and Nishioka[2]. It was named after Tufts University where the peptide was discovered. | https://www.wikidoc.org/index.php/Tuftsin | |
dff2bfa504b6c0cd1dc395185dd3d6b672cd0733 | wikidoc | Turbine | Turbine
A turbine is a rotary engine that extracts energy from a fluid flow. Claude Burdin (1788-1873) coined the term from the Latin turbo, or vortex, during an 1828 engineering competition. Benoit Fourneyron (1802-1867), a student of Claude Burdin, built the first practical water turbine.
The simplest turbines have one moving part, a rotor assembly, which is a shaft with blades attached. Moving fluid acts on the blades, or the blades react to the flow, so that they rotate and impart energy to the rotor. Early turbine examples are windmills and water wheels.
Gas, steam, and water turbines have a casing around the blades that contains and controls the working fluid. Credit for invention of the modern steam turbine is given to British Engineer Sir Charles Parsons (1854 - 1931).
A device similar to a turbine but operating in reverse is a compressor or pump. The axial compressor in many gas turbine engines is a common example.
# Theory of operation
A working fluid contains potential energy (pressure head) and kinetic energy (velocity head). The fluid may be compressible or incompressible. Several physical principles are employed by turbines to collect this energy:
Turbine designs will use both these concepts to varying degrees whenever possible. Wind turbines use an airfoil to generate lift from the moving fluid and impart it to the rotor (this is a form of reaction). Wind turbines also gain some energy from the impulse of the wind, by deflecting it at an angle. Crossflow turbines are designed as an impulse machine, with a nozzle, but in low head applications maintain some efficiency through reaction, like a traditional water wheel. Turbines with multiple stages may utilize either reaction or impulse blading at high pressure. Steam Turbines were traditionally more impulse but continue to move towards reaction designs similar to those used in Gas Turbines. At low pressure the operating fluid medium expands in volume for small reductions in pressure. Under these conditions (termed Low Pressure Turbines) blading becomes strictly a reaction type design with the base of the blade solely impulse. The reason is due to the effect of the rotation speed for each blade. As the volume increases, the blade height increases, and the base of the blade spins at a slower speed relative to the tip. This change in speed forces a designer to change from impulse at the base, to a high reaction style tip.
Classical turbine design methods were developed in the mid 19th century. Vector analysis related the fluid flow with turbine shape and rotation. Graphical calculation methods were used at first. Formulas for the basic dimensions of turbine parts are well documented and a highly efficient machine can be reliably designed for any fluid flow condition. Some of the calculations are empirical or 'rule of thumb' formulae, and others are based on classical mechanics. As with most engineering calculations, simplifying assumptions were made.
Velocity triangles can be used to calculate the basic performance of a turbine stage. Gas exits the stationary turbine nozzle guide vanes at absolute velocity Va1. The rotor rotates at velocity U. Relative to the rotor, the velocity of the gas as it impinges on the rotor entrance is Vr1. The gas is turned by the rotor and exits, relative to the rotor, at velocity Vr2. However, in absolute terms the rotor exit velocity is Va2. The velocity triangles are constructed using these various velocity vectors. Velocity triangles can be constructed at any section through the blading (for example: hub , tip, midsection and so on) but are usually shown at the mean stage radius. Mean performance for the stage can be calculated from the velocity triangles, at this radius, using the Euler equation:
Whence:
where:
The turbine pressure ratio is a function of \left(\frac{\Delta\;H}{T}\right) and the turbine efficiency.
Modern turbine design carries the calculations further. Computational fluid dynamics dispenses with many of the simplifying assumptions used to derive classical formulas and computer software facilitates optimization. These tools have led to steady improvements in turbine design over the last forty years.
The primary numerical classification of a turbine is its specific speed. This number describes the speed of the turbine at its maximum efficiency with respect to the power and flow rate. The specific speed is derived to be independent of turbine size. Given the fluid flow conditions and the desired shaft output speed, the specific speed can be calculated and an appropriate turbine design selected.
The specific speed, along with some fundamental formulas can be used to reliably scale an existing design of known performance to a new size with corresponding performance.
Off-design performance is normally displayed as a turbine map or characteristic.
# Types of turbines
- Steam turbines are used for the generation of electricity in thermal power plants, such as plants using coal or fuel oil or nuclear power. They were once used to directly drive mechanical devices such as ship's propellors (eg the Turbinia), but most such applications now use reduction gears or an intermediate electrical step, where the turbine is used to generate electricity, which then powers an electric motor connected to the mechanical load.
- Gas turbines are sometimes referred to as turbine engines. Such engines usually feature an inlet, fan, compressor, combustor and nozzle (possibly other assemblies) in addition to one or more turbines.
- Transonic turbine. The gasflow in most turbines employed in gas turbine engines remains subsonic throughout the expansion process. In a transonic turbine the gasflow becomes supersonic as it exits the nozzle guide vanes, although the downstream velocities normally become subsonic. Transonic turbines operate at a higher pressure ratio than normal but are usually less efficient and uncommon. This turbine works well in creating power from water.
- Contra-rotating turbines. Some efficiency advantage can be obtained if a downstream turbine rotates in the opposite direction to an upstream unit. However, the complication may be counter-productive.
- Statorless turbine Multi-stage turbines have a set of static (meaning stationary) inlet guide vanes that direct the gasflow onto the rotating rotor blades. In a statorless turbine the gasflow exiting an upstream rotor impinges onto a downstream rotor without an intermediate set of stator vanes (that rearrange the pressure/velocity energy levels of the flow) being encountered.
- Ceramic turbine. Conventional high-pressure turbine blades (and vanes) are made from nickel-steel alloys and often utilise intricate internal air-cooling passages to prevent the metal from melting. In recent years, experimental ceramic blades have been manufactured and tested in gas turbines, with a view to increasing Rotor Inlet Temperatures and/or, possibly, eliminating aircooling. Ceramic blades are more brittle than their metallic counterparts, and carry a greater risk of catastrophic blade failure.
- Shrouded turbine. Many turbine rotor blades have a shroud at the top, which interlocks with that of adjacent blades, to increase damping and thereby reduce blade flutter.
- Shroudless turbine. Modern practise is, where possible, to eliminate the rotor shroud, thus reducing the centrifugal load on the blade and the cooling requirements.
- Bladeless turbine uses the boundary layer effect and not a fluid impinging upon the blades as in a conventional turbine.
- Water turbines
Francis Turbine, a type of widely used water turbine.
Kaplan Turbine, a variation of the Francis Turbine.
- Francis Turbine, a type of widely used water turbine.
Kaplan Turbine, a variation of the Francis Turbine.
- Kaplan Turbine, a variation of the Francis Turbine.
- Wind turbine. These normally operate as a single stage without nozzle and interstage guide vanes. An exception is the Éolienne Bollée, which has a stator and a rotor, thus being a true turbine.
## Other
- Velocity compound "Curtis". Curtis combined the de Laval and Parsons turbine by using a set of fixed nozzles on the first stage or stator and then a rank of fixed and rotating stators as in the Parsons, typically up to ten compared with up to a hundred stages, however the efficiency of the turbine was less than that of the Parsons but it operated at much lower speeds and at lower pressures which made it ideal for ships. Note that the use of a small section of a Curtis, typically one nozzle section and two rotors is termed a "Curtis Wheel"
- Pressure Compund Multistage Impulse or Rateau. The Rateau employs simple Impulse rotors separated by a nozzle diaphragm. The diaphragm is essentially a partition wall in the turbine with a series of tunnels cut into it, funnel shaped with the broad end facing the previous stage and the narrow the next they are also angled to direct the steam jets onto the impulse rotor.
# Uses of turbines
Almost all electrical power on Earth is produced with a turbine of some type. Very high efficiency turbines harness about 40% of the thermal energy, with the rest exhausted as waste heat.
Most jet engines rely on turbines to supply mechanical work from their working fluid and fuel as do all nuclear ships and power plants.
Turbines are often part of a larger machine. A gas turbine, for example, may refer to an internal combustion machine that contains a turbine, ducts, compressor, combustor, heat-exchanger, fan and (in the case of one designed to produce electricity) an alternator. However, it must be noted that the collective machine referred to as the turbine in these cases is designed to transfer energy from a fuel to the fluid passing through such an internal combustion device as a means of propulsion, and not to transfer energy from the fluid passing through the turbine to the turbine as is the case in turbines used for electricity provision etc.
Reciprocating piston engines such as aircraft engines can use a turbine powered by their exhaust to drive an intake-air compressor, a configuration known as a turbocharger (turbine supercharger) or, colloquially, a "turbo".
Turbines can have very high power density (ie the ratio of power to weight, or power to volume). This is because of their ability to operate at very high speeds. The Space Shuttle's main engines use turbopumps (machines consisting of a pump driven by a turbine engine) to feed the propellants (liquid oxygen and liquid hydrogen) into the engine's combustion chamber. The liquid hydrogen turbopump is slightly larger than an automobile engine (weighing approximately 700 lb) and produces nearly 70,000 hp (52.2 MW).
Turboexpanders are widely used as sources of refrigeration in industrial processes.
Turbines could also be used as powering system for a remote controlled plane that creates thrust and lifts the plane of the ground. They come in different sizes and could be as small as soda can, still be strong enough to move objects with a weight of 100kg.
# Shrouded tidal turbines
An emerging renewable energy technology is the shrouded tidal turbine enclosed in a venturi shaped shroud or duct producing a sub atmosphere of low pressure behind the turbine, allowing the turbine to operate at higher efficiency (than the Betz limit of 59.3%) and typically 3 times higher power output than a turbine of the same size in free stream.
As shown in the CFD generated figure, it can be seen that a down stream low pressure (shown by the gradient lines) draws upstream flow into the inlet of the shroud from well outside the inlet of the shroud. This flow is drawn into the shroud and concentrated (as seen by the red coloured zone). This augmentation of flow velocity corresponds to a 3-4 times increase in energy available to the turbine. Therefore a turbine located in the throat of the shroud is then able to achieve higher efficiency, and an output 3-4 times the energy the turbine would be capable of if it were in open or free stream. For this reason shrouded turbines are not subject to the properties of the Betz limit.
Considerable commercial interest has been shown in recent times in shrouded tidal turbines as it allows a smaller turbine to be used at sites where large turbines are restricted. Arrayed across a seaway or in fast flowing rivers shrouded tidal turbines are easily cabled to a terrestrial base and connected to a grid or remote community. Alternatively the property of the shroud that produces an accelerated flow velocity across the turbine allows tidal flows formerly too slow for commercial use to be utilised for commercial energy production.
While the shroud may not be practical in wind, as a tidal turbine it is gaining more popularity and commercial use. A shrouded tidal turbine is mono directional and constantly needs to face upstream in order to operate. It can be floated under a pontoon on a swing mooring, fixed to the seabed on a mono pile and yawed like a wind sock to continually face upstream. A shroud can also be built into a tidal fence increasing the performance of the turbines.
Cabled to the mainland they can be grid connected or can be scaled down to provide energy to remote communities where large civil infrastructures are not viable. Similarly to tidal stream open turbines they have little if any environmental or visual amenity impact. | Turbine
A turbine is a rotary engine that extracts energy from a fluid flow. Claude Burdin (1788-1873) coined the term from the Latin turbo, or vortex, during an 1828 engineering competition. Benoit Fourneyron (1802-1867), a student of Claude Burdin, built the first practical water turbine.
The simplest turbines have one moving part, a rotor assembly, which is a shaft with blades attached. Moving fluid acts on the blades, or the blades react to the flow, so that they rotate and impart energy to the rotor. Early turbine examples are windmills and water wheels.
Gas, steam, and water turbines have a casing around the blades that contains and controls the working fluid. Credit for invention of the modern steam turbine is given to British Engineer Sir Charles Parsons (1854 - 1931).
A device similar to a turbine but operating in reverse is a compressor or pump. The axial compressor in many gas turbine engines is a common example.
# Theory of operation
A working fluid contains potential energy (pressure head) and kinetic energy (velocity head). The fluid may be compressible or incompressible. Several physical principles are employed by turbines to collect this energy:
Turbine designs will use both these concepts to varying degrees whenever possible. Wind turbines use an airfoil to generate lift from the moving fluid and impart it to the rotor (this is a form of reaction). Wind turbines also gain some energy from the impulse of the wind, by deflecting it at an angle. Crossflow turbines are designed as an impulse machine, with a nozzle, but in low head applications maintain some efficiency through reaction, like a traditional water wheel. Turbines with multiple stages may utilize either reaction or impulse blading at high pressure. Steam Turbines were traditionally more impulse but continue to move towards reaction designs similar to those used in Gas Turbines. At low pressure the operating fluid medium expands in volume for small reductions in pressure. Under these conditions (termed Low Pressure Turbines) blading becomes strictly a reaction type design with the base of the blade solely impulse. The reason is due to the effect of the rotation speed for each blade. As the volume increases, the blade height increases, and the base of the blade spins at a slower speed relative to the tip. This change in speed forces a designer to change from impulse at the base, to a high reaction style tip.
Classical turbine design methods were developed in the mid 19th century. Vector analysis related the fluid flow with turbine shape and rotation. Graphical calculation methods were used at first. Formulas for the basic dimensions of turbine parts are well documented and a highly efficient machine can be reliably designed for any fluid flow condition. Some of the calculations are empirical or 'rule of thumb' formulae, and others are based on classical mechanics. As with most engineering calculations, simplifying assumptions were made.
Velocity triangles can be used to calculate the basic performance of a turbine stage. Gas exits the stationary turbine nozzle guide vanes at absolute velocity Va1. The rotor rotates at velocity U. Relative to the rotor, the velocity of the gas as it impinges on the rotor entrance is Vr1. The gas is turned by the rotor and exits, relative to the rotor, at velocity Vr2. However, in absolute terms the rotor exit velocity is Va2. The velocity triangles are constructed using these various velocity vectors. Velocity triangles can be constructed at any section through the blading (for example: hub , tip, midsection and so on) but are usually shown at the mean stage radius. Mean performance for the stage can be calculated from the velocity triangles, at this radius, using the Euler equation:
Whence:
where:
The turbine pressure ratio is a function of <math>\left(\frac{\Delta\;H}{T}\right)</math> and the turbine efficiency.
Modern turbine design carries the calculations further. Computational fluid dynamics dispenses with many of the simplifying assumptions used to derive classical formulas and computer software facilitates optimization. These tools have led to steady improvements in turbine design over the last forty years.
The primary numerical classification of a turbine is its specific speed. This number describes the speed of the turbine at its maximum efficiency with respect to the power and flow rate. The specific speed is derived to be independent of turbine size. Given the fluid flow conditions and the desired shaft output speed, the specific speed can be calculated and an appropriate turbine design selected.
The specific speed, along with some fundamental formulas can be used to reliably scale an existing design of known performance to a new size with corresponding performance.
Off-design performance is normally displayed as a turbine map or characteristic.
# Types of turbines
- Steam turbines are used for the generation of electricity in thermal power plants, such as plants using coal or fuel oil or nuclear power. They were once used to directly drive mechanical devices such as ship's propellors (eg the Turbinia), but most such applications now use reduction gears or an intermediate electrical step, where the turbine is used to generate electricity, which then powers an electric motor connected to the mechanical load.
- Gas turbines are sometimes referred to as turbine engines. Such engines usually feature an inlet, fan, compressor, combustor and nozzle (possibly other assemblies) in addition to one or more turbines.
- Transonic turbine. The gasflow in most turbines employed in gas turbine engines remains subsonic throughout the expansion process. In a transonic turbine the gasflow becomes supersonic as it exits the nozzle guide vanes, although the downstream velocities normally become subsonic. Transonic turbines operate at a higher pressure ratio than normal but are usually less efficient and uncommon. This turbine works well in creating power from water.
- Contra-rotating turbines. Some efficiency advantage can be obtained if a downstream turbine rotates in the opposite direction to an upstream unit. However, the complication may be counter-productive.
- Statorless turbine Multi-stage turbines have a set of static (meaning stationary) inlet guide vanes that direct the gasflow onto the rotating rotor blades. In a statorless turbine the gasflow exiting an upstream rotor impinges onto a downstream rotor without an intermediate set of stator vanes (that rearrange the pressure/velocity energy levels of the flow) being encountered.
- Ceramic turbine. Conventional high-pressure turbine blades (and vanes) are made from nickel-steel alloys and often utilise intricate internal air-cooling passages to prevent the metal from melting. In recent years, experimental ceramic blades have been manufactured and tested in gas turbines, with a view to increasing Rotor Inlet Temperatures and/or, possibly, eliminating aircooling. Ceramic blades are more brittle than their metallic counterparts, and carry a greater risk of catastrophic blade failure.
- Shrouded turbine. Many turbine rotor blades have a shroud at the top, which interlocks with that of adjacent blades, to increase damping and thereby reduce blade flutter.
- Shroudless turbine. Modern practise is, where possible, to eliminate the rotor shroud, thus reducing the centrifugal load on the blade and the cooling requirements.
- Bladeless turbine uses the boundary layer effect and not a fluid impinging upon the blades as in a conventional turbine.
- Water turbines
Francis Turbine, a type of widely used water turbine.
Kaplan Turbine, a variation of the Francis Turbine.
- Francis Turbine, a type of widely used water turbine.
Kaplan Turbine, a variation of the Francis Turbine.
- Kaplan Turbine, a variation of the Francis Turbine.
- Wind turbine. These normally operate as a single stage without nozzle and interstage guide vanes. An exception is the Éolienne Bollée, which has a stator and a rotor, thus being a true turbine.
## Other
- Velocity compound "Curtis". Curtis combined the de Laval and Parsons turbine by using a set of fixed nozzles on the first stage or stator and then a rank of fixed and rotating stators as in the Parsons, typically up to ten compared with up to a hundred stages, however the efficiency of the turbine was less than that of the Parsons but it operated at much lower speeds and at lower pressures which made it ideal for ships. Note that the use of a small section of a Curtis, typically one nozzle section and two rotors is termed a "Curtis Wheel"
- Pressure Compund Multistage Impulse or Rateau. The Rateau employs simple Impulse rotors separated by a nozzle diaphragm. The diaphragm is essentially a partition wall in the turbine with a series of tunnels cut into it, funnel shaped with the broad end facing the previous stage and the narrow the next they are also angled to direct the steam jets onto the impulse rotor.
# Uses of turbines
Almost all electrical power on Earth is produced with a turbine of some type. Very high efficiency turbines harness about 40% of the thermal energy, with the rest exhausted as waste heat.
Most jet engines rely on turbines to supply mechanical work from their working fluid and fuel as do all nuclear ships and power plants.
Turbines are often part of a larger machine. A gas turbine, for example, may refer to an internal combustion machine that contains a turbine, ducts, compressor, combustor, heat-exchanger, fan and (in the case of one designed to produce electricity) an alternator. However, it must be noted that the collective machine referred to as the turbine in these cases is designed to transfer energy from a fuel to the fluid passing through such an internal combustion device as a means of propulsion, and not to transfer energy from the fluid passing through the turbine to the turbine as is the case in turbines used for electricity provision etc.
Reciprocating piston engines such as aircraft engines can use a turbine powered by their exhaust to drive an intake-air compressor, a configuration known as a turbocharger (turbine supercharger) or, colloquially, a "turbo".
Turbines can have very high power density (ie the ratio of power to weight, or power to volume). This is because of their ability to operate at very high speeds. The Space Shuttle's main engines use turbopumps (machines consisting of a pump driven by a turbine engine) to feed the propellants (liquid oxygen and liquid hydrogen) into the engine's combustion chamber. The liquid hydrogen turbopump is slightly larger than an automobile engine (weighing approximately 700 lb) and produces nearly 70,000 hp (52.2 MW).
Turboexpanders are widely used as sources of refrigeration in industrial processes.
Turbines could also be used as powering system for a remote controlled plane that creates thrust and lifts the plane of the ground. They come in different sizes and could be as small as soda can, still be strong enough to move objects with a weight of 100kg.
# Shrouded tidal turbines
An emerging renewable energy technology is the shrouded tidal turbine enclosed in a venturi shaped shroud or duct producing a sub atmosphere of low pressure behind the turbine, allowing the turbine to operate at higher efficiency (than the Betz limit [1] of 59.3%) and typically 3 times higher power output [2] than a turbine of the same size in free stream.
As shown in the CFD generated figure[3], it can be seen that a down stream low pressure (shown by the gradient lines) draws upstream flow into the inlet of the shroud from well outside the inlet of the shroud. This flow is drawn into the shroud and concentrated (as seen by the red coloured zone). This augmentation of flow velocity corresponds to a 3-4 times increase in energy available to the turbine. Therefore a turbine located in the throat of the shroud is then able to achieve higher efficiency, and an output 3-4 times the energy the turbine would be capable of if it were in open or free stream. For this reason shrouded turbines are not subject to the properties of the Betz limit.
Considerable commercial interest has been shown in recent times in shrouded tidal turbines as it allows a smaller turbine to be used at sites where large turbines are restricted. Arrayed across a seaway or in fast flowing rivers shrouded tidal turbines are easily cabled to a terrestrial base and connected to a grid or remote community. Alternatively the property of the shroud that produces an accelerated flow velocity across the turbine allows tidal flows formerly too slow for commercial use to be utilised for commercial energy production.
While the shroud may not be practical in wind, as a tidal turbine it is gaining more popularity and commercial use. A shrouded tidal turbine is mono directional and constantly needs to face upstream in order to operate. It can be floated under a pontoon on a swing mooring, fixed to the seabed on a mono pile and yawed like a wind sock to continually face upstream. A shroud can also be built into a tidal fence increasing the performance of the turbines.
Cabled to the mainland they can be grid connected or can be scaled down to provide energy to remote communities where large civil infrastructures are not viable. Similarly to tidal stream open turbines they have little if any environmental or visual amenity impact. | https://www.wikidoc.org/index.php/Turbine | |
9a7d7884ba9b82bf7d9cf8331003a4e2ae531e79 | wikidoc | Twinrix | Twinrix
# Overview
Twinrix is a vaccine against hepatitis A and hepatitis B. Twinrix is administered over three doses.
The name was created because it is a mixture of two earlier vaccines - Havrix, an inactivated-virus Hepatitis A vaccine, and ENGERIX-B, a recombinant Hepatitis B vaccine.
The CDC reports that clinical trials found the following levels of protection against Hep A and Hep B one month after each dose:
A: 93.8% 98.8% 99.9%
B: 30.8% 78.2% 98.5%
GlaxoSmithKline claims that its studies found 70% of subjects had antibodies against hepatitis B a month after just the first dose, however.
TWINRIX, HAVRIX and ENGERIX-B are registered trademarks of
GlaxoSmithKline; if the same vaccine is available from others, it will have another name. | Twinrix
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]
# Overview
Twinrix is a vaccine against hepatitis A and hepatitis B. Twinrix is administered over three doses.
The name was created because it is a mixture of two earlier vaccines - Havrix, an inactivated-virus Hepatitis A vaccine, and ENGERIX-B, a recombinant Hepatitis B vaccine.
The CDC reports that clinical trials found the following levels of protection against Hep A and Hep B one month after each dose[1]:
A: 93.8% 98.8% 99.9%
B: 30.8% 78.2% 98.5%
GlaxoSmithKline claims that its studies found 70% of subjects had antibodies against hepatitis B a month after just the first dose, however.[2]
TWINRIX, HAVRIX and ENGERIX-B are registered trademarks of
GlaxoSmithKline; if the same vaccine is available from others, it will have another name. | https://www.wikidoc.org/index.php/Twinrix | |
2647260bbf1ea39d500c2bab25353b201aae8fce | wikidoc | UGT1A10 | UGT1A10
UDP-glucuronosyltransferase 1-10 is an enzyme that in humans is encoded by the UGT1A10 gene.
This gene encodes a UDP-glucuronosyltransferase, an enzyme of the glucuronidation pathway that transforms small lipophilic molecules, such as steroids, bilirubin, hormones, and drugs, into water-soluble, excretable metabolites. This gene is part of a complex locus that encodes several UDP-glucuronosyltransferases. The locus includes thirteen unique alternate first exons followed by four common exons. Four of the alternate first exons are considered pseudogenes. Each of the remaining nine 5' exons may be spliced to the four common exons, resulting in nine proteins with different N-termini and identical C-termini. Each first exon encodes the substrate binding site, and is regulated by its own promoter. The enzyme encoded by this gene has glucuronidase activity on mycophenolic acid, coumarins, and quinolines.
# Interactive pathway map
Click on genes, proteins and metabolites below to link to respective articles.
- ↑ The interactive pathway map can be edited at WikiPathways: "IrinotecanPathway_WP46359"..mw-parser-output cite.citation{font-style:inherit}.mw-parser-output q{quotes:"\"""\"""'""'"}.mw-parser-output code.cs1-code{color:inherit;background:inherit;border:inherit;padding:inherit}.mw-parser-output .cs1-lock-free a{background:url("")no-repeat;background-position:right .1em center}.mw-parser-output .cs1-lock-limited a,.mw-parser-output .cs1-lock-registration a{background:url("")no-repeat;background-position:right .1em center}.mw-parser-output .cs1-lock-subscription a{background:url("")no-repeat;background-position:right .1em center}.mw-parser-output .cs1-subscription,.mw-parser-output .cs1-registration{color:#555}.mw-parser-output .cs1-subscription span,.mw-parser-output .cs1-registration span{border-bottom:1px dotted;cursor:help}.mw-parser-output .cs1-hidden-error{display:none;font-size:100%}.mw-parser-output .cs1-visible-error{display:none;font-size:100%}.mw-parser-output .cs1-subscription,.mw-parser-output .cs1-registration,.mw-parser-output .cs1-format{font-size:95%}.mw-parser-output .cs1-kern-left,.mw-parser-output .cs1-kern-wl-left{padding-left:0.2em}.mw-parser-output .cs1-kern-right,.mw-parser-output .cs1-kern-wl-right{padding-right:0.2em} | UGT1A10
UDP-glucuronosyltransferase 1-10 is an enzyme that in humans is encoded by the UGT1A10 gene.[1][2][3]
This gene encodes a UDP-glucuronosyltransferase, an enzyme of the glucuronidation pathway that transforms small lipophilic molecules, such as steroids, bilirubin, hormones, and drugs, into water-soluble, excretable metabolites. This gene is part of a complex locus that encodes several UDP-glucuronosyltransferases. The locus includes thirteen unique alternate first exons followed by four common exons. Four of the alternate first exons are considered pseudogenes. Each of the remaining nine 5' exons may be spliced to the four common exons, resulting in nine proteins with different N-termini and identical C-termini. Each first exon encodes the substrate binding site, and is regulated by its own promoter. The enzyme encoded by this gene has glucuronidase activity on mycophenolic acid, coumarins, and quinolines.[3]
# Interactive pathway map
Click on genes, proteins and metabolites below to link to respective articles. [§ 1]
- ↑ The interactive pathway map can be edited at WikiPathways: "IrinotecanPathway_WP46359"..mw-parser-output cite.citation{font-style:inherit}.mw-parser-output q{quotes:"\"""\"""'""'"}.mw-parser-output code.cs1-code{color:inherit;background:inherit;border:inherit;padding:inherit}.mw-parser-output .cs1-lock-free a{background:url("https://upload.wikimedia.org/wikipedia/commons/thumb/6/65/Lock-green.svg/9px-Lock-green.svg.png")no-repeat;background-position:right .1em center}.mw-parser-output .cs1-lock-limited a,.mw-parser-output .cs1-lock-registration a{background:url("https://upload.wikimedia.org/wikipedia/commons/thumb/d/d6/Lock-gray-alt-2.svg/9px-Lock-gray-alt-2.svg.png")no-repeat;background-position:right .1em center}.mw-parser-output .cs1-lock-subscription a{background:url("https://upload.wikimedia.org/wikipedia/commons/thumb/a/aa/Lock-red-alt-2.svg/9px-Lock-red-alt-2.svg.png")no-repeat;background-position:right .1em center}.mw-parser-output .cs1-subscription,.mw-parser-output .cs1-registration{color:#555}.mw-parser-output .cs1-subscription span,.mw-parser-output .cs1-registration span{border-bottom:1px dotted;cursor:help}.mw-parser-output .cs1-hidden-error{display:none;font-size:100%}.mw-parser-output .cs1-visible-error{display:none;font-size:100%}.mw-parser-output .cs1-subscription,.mw-parser-output .cs1-registration,.mw-parser-output .cs1-format{font-size:95%}.mw-parser-output .cs1-kern-left,.mw-parser-output .cs1-kern-wl-left{padding-left:0.2em}.mw-parser-output .cs1-kern-right,.mw-parser-output .cs1-kern-wl-right{padding-right:0.2em} | https://www.wikidoc.org/index.php/UGT1A10 | |
81d93b1ecabadf7f5418c7a98fa599c9e2ae34ce | wikidoc | UNC93B1 | UNC93B1
Unc-93 homolog B1 (C. elegans), also known as UNC93B1, is a protein which in humans is encoded by the UNC93B1 gene.
# Function
This gene encodes a protein with similarity to the Caenorhabditis elegans unc93 protein. The Unc93 protein is involved in the regulation or coordination of muscle contraction in the worm.
# Molecular biology
The gene is located on long arm of chromosome 11 (11q13) on the minus (Crick) strand and was first identified in 2002. This protein is an intrinsic membrane protein that spans the membrane twelve times. It is found in the endoplasmic reticulum and is highly conserved.
# Clinical importance
Unc93B1 protein appears to be involved in the innate immune response. Defects in the protein predispose to hypersensitity to infections with herpes simplex virus and mouse cytomegalovirus. The mechanism is unclear but Unc93B1 is known to interact with the toll-like receptors TLR3, TLR7 and TLR9 and it appears to be involved in the trafficking of these receptors within the cell. Mutations in this gene lead to selective impairment of dsRNA-induced interferon alpha/beta and interferon 1 lambda production.
The intracellular toll-like receptors have been shown to interact with UNC93B in splenocytes and bone marrow-derived dendritic cells. TLR3 and TLR9 bind to UNC93B via their transmembrane domains. Introduction of the point mutation H412R (histidine to arginine at amino acid 412: a single base transition - adenosine to guanine at base 1235) in UNC93B abolishes this interaction. | UNC93B1
Unc-93 homolog B1 (C. elegans), also known as UNC93B1, is a protein which in humans is encoded by the UNC93B1 gene.[1][2]
# Function
This gene encodes a protein with similarity to the Caenorhabditis elegans unc93 protein. The Unc93 protein is involved in the regulation or coordination of muscle contraction in the worm.[1]
# Molecular biology
The gene is located on long arm of chromosome 11 (11q13) on the minus (Crick) strand[2] and was first identified in 2002.[2] This protein is an intrinsic membrane protein that spans the membrane twelve times. It is found in the endoplasmic reticulum and is highly conserved.
# Clinical importance
Unc93B1 protein appears to be involved in the innate immune response. Defects in the protein predispose to hypersensitity to infections with herpes simplex virus and mouse cytomegalovirus.[3] The mechanism is unclear but Unc93B1 is known to interact with the toll-like receptors TLR3, TLR7 and TLR9 and it appears to be involved in the trafficking of these receptors within the cell.[4][5] Mutations in this gene lead to selective impairment of dsRNA-induced interferon alpha/beta and interferon 1 lambda production.
The intracellular toll-like receptors have been shown to interact with UNC93B in splenocytes and bone marrow-derived dendritic cells. TLR3 and TLR9 bind to UNC93B via their transmembrane domains. Introduction of the point mutation H412R (histidine to arginine at amino acid 412: a single base transition - adenosine to guanine at base 1235) in UNC93B abolishes this interaction. | https://www.wikidoc.org/index.php/UNC93B1 | |
3c9c8df92ef5a71d285e15cc82c792aec0702d2b | wikidoc | Unitaid | Unitaid
# Overview
UNITAID is an international facility for the purchase of drugs against HIV/AIDS, Malaria and Tuberculosis. It was founded in September 2006 on the initiative of Brazil and France, and is to a great part financed by so called innovative development financing mechanisms, namely a solidarity levy on air line tickets.
Due to a growing number of Member States (35 as of April 2007) UNITAID's budget is expected to exceed $500 million in 2009 ($300 million in 2007) out of which at least 85% must be allocated to low-income countries. Hosted by the WHO in Geneva, the organization's principal strength is the negotiation of low prices for drugs on the basis of its strong financial means. UNITAID does not have its own programs for the distribution of medication but supports programs by its partner organizations such as The Global Fund, the Clinton Foundation, or the WHO.
# History
All political actions toward the establishment of UNITAID had been preceded by two major reports on innovative financing: The Report of the Technical Group on Innovative Financing Mechanisms was formulated upon request by the Heads of State of Brazil, Chile, France and Spain and was published in September 2004; the Landau-report originated in a request by French President Jacques Chirac and was issued in December 2004. Both documents present various opportunities for innovative financing mechanisms while equally stressing the advantages (stability and predictability) of tax-based models.
After these documents had been published, the countries involved in the process tried to turn the international community's attention on innovative development financing. For instance, in February 2005 a joint statement was published by Brazil, Chile, France, Germany, and Spain offering ideas for the financing of the Millennium Development Goals (MDGs); in September of the same year a declaration was announced at a UN-meeting on the MDGs in New York, asking for further examination of innovative sources of financing ; this again was followed by an international conference on “Solidarity and Globalization: innovative financing for development and against pandemics”, held between February 28 and March 1, 2006 in Paris. In the follow-up of this conference, a pilot group on innovative financing of 44 countries was established, and France decided to introduce a solidarity tax on airline tickets, which entered into force on 1 July, 2006. Finally, on 17 September 2006, UNITAID is founded by Brazil, Chile, France, Norway and the United Kingdom - while not all of them use air ticket taxation to fulfill their commitment to UNITAID.
Since then, more countries have joined the initiative, among them notably 18 African countries that contribute to UNITAID's funds since Februar 2007.
# Activities & Achievements
UNITAID's primary goal is to ensure access to drugs against the most deadly global diseases - HIV/AIDS, Malaria and Tuberculosis.
In this context, UNITAID's secondary goals are:
- to negotiate low prices for already existing forms of medication and to purchase them in high quantities; and
- to incite the development and mass production of special drugs that do not yet exist or are not yet affordable, such as specifically dosed (paediatric) treatment for HIV/AIDS-infected children or medication for people that have become resistant to standard treatment (so called "Second-line" drugs).
- Anti-retroviral treatment (achieved price reduction: 40%) for 100,000 AIDS-infected children in 34 Asian and African countries by the end of 2007 (partner: Clinton Foundation)
- Funding of the treatment for 150,000 children suffering from Tuberculosis from September 2007 on (partners: Stop TB Partnership and the Global Drug Facility)
- Funding of artemisinin-based combination therapies against Malaria in 19 countries (partners: UNICEF and The Global Fund)
- UNITAID also provides money for a WHO program for the prequalification of drugs and will help UNICEF supply pregnant women with HIV test kits and special anti-retroviral treatment.
# Structure
Due to its restricted scope of action, UNITAID has a very consise inner structure:
- The President is UNITAID's official representative. On 3 March 2007, French Foreign Minister Philippe Douste-Blazy was elected president of UNITAID for a two-year term.
- The Secretariat is located at Geneva, in the WHO-facilities, and is responsible for the day-to-day work of the organization. On 4 May 2007, Dr. Jorge Antonio Zepeda Bermudez (Brezil) will take office as the UNITAID Executive Secretary.
- The Board is the decision-making body of UNITAID. It decides on how the money is spent, which partnerships are being concluded, it sets the main objectives for the future and decides on action plans. The board has ten members, including five representatives from the founding countries (Brazil, Chile, France, Norway and the United Kingdom), one from Africa chosen by the African Union, one from Asia (South Korea), two from the civil society ( NGOs and communities of people living with the diseases) and one from the WHO. | Unitaid
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]
# Overview
UNITAID is an international facility for the purchase of drugs against HIV/AIDS, Malaria and Tuberculosis. It was founded in September 2006 on the initiative of Brazil and France, and is to a great part financed by so called innovative development financing mechanisms, namely a solidarity levy on air line tickets.
Due to a growing number of Member States (35 as of April 2007) UNITAID's budget is expected to exceed $500 million in 2009 ($300 million in 2007)[1] out of which at least 85% must be allocated to low-income countries. Hosted by the WHO in Geneva, the organization's principal strength is the negotiation of low prices for drugs on the basis of its strong financial means. UNITAID does not have its own programs for the distribution of medication but supports programs by its partner organizations such as The Global Fund, the Clinton Foundation, or the WHO.
# History
All political actions toward the establishment of UNITAID had been preceded by two major reports on innovative financing: The Report of the Technical Group on Innovative Financing Mechanisms [2] was formulated upon request by the Heads of State of Brazil, Chile, France and Spain and was published in September 2004; the Landau-report [3] originated in a request by French President Jacques Chirac and was issued in December 2004. Both documents present various opportunities for innovative financing mechanisms while equally stressing the advantages (stability and predictability) of tax-based models.
After these documents had been published, the countries involved in the process tried to turn the international community's attention on innovative development financing. For instance, in February 2005 a joint statement [4] was published by Brazil, Chile, France, Germany, and Spain offering ideas for the financing of the Millennium Development Goals (MDGs); in September of the same year a declaration was announced at a UN-meeting on the MDGs in New York, asking for further examination of innovative sources of financing [5]; this again was followed by an international conference on “Solidarity and Globalization: innovative financing for development and against pandemics”, held between February 28 and March 1, 2006 in Paris. In the follow-up of this conference, a pilot group on innovative financing of 44 countries was established, and France decided to introduce a solidarity tax on airline tickets, which entered into force on 1 July, 2006. Finally, on 17 September 2006, UNITAID is founded by Brazil, Chile, France, Norway and the United Kingdom - while not all of them use air ticket taxation to fulfill their commitment to UNITAID.[2]
Since then, more countries have joined the initiative, among them notably 18 African countries that contribute to UNITAID's funds since Februar 2007.[3]
# Activities & Achievements
UNITAID's primary goal is to ensure access to drugs against the most deadly global diseases - HIV/AIDS, Malaria and Tuberculosis.[4]
In this context, UNITAID's secondary goals are:
- to negotiate low prices for already existing forms of medication and to purchase them in high quantities; and
- to incite the development and mass production of special drugs that do not yet exist or are not yet affordable, such as specifically dosed (paediatric) treatment for HIV/AIDS-infected children or medication for people that have become resistant to standard treatment (so called "Second-line" drugs).[5]
- Anti-retroviral treatment (achieved price reduction: 40%) for 100,000 AIDS-infected children in 34 Asian and African countries by the end of 2007 (partner: Clinton Foundation)
- Funding of the treatment for 150,000 children suffering from Tuberculosis from September 2007 on (partners: Stop TB Partnership and the Global Drug Facility)
- Funding of artemisinin-based combination therapies against Malaria in 19 countries (partners: UNICEF and The Global Fund)
- UNITAID also provides money for a WHO program for the prequalification of drugs and will help UNICEF supply pregnant women with HIV test kits and special anti-retroviral treatment.
# Structure
Due to its restricted scope of action, UNITAID has a very consise inner structure:
- The President is UNITAID's official representative. On 3 March 2007, French Foreign Minister Philippe Douste-Blazy was elected president of UNITAID for a two-year term.
- The Secretariat is located at Geneva, in the WHO-facilities, and is responsible for the day-to-day work of the organization. On 4 May 2007, Dr. Jorge Antonio Zepeda Bermudez (Brezil) will take office as the UNITAID Executive Secretary.
- The Board is the decision-making body of UNITAID. It decides on how the money is spent, which partnerships are being concluded, it sets the main objectives for the future and decides on action plans. The board has ten members, including five representatives from the founding countries (Brazil, Chile, France, Norway and the United Kingdom), one from Africa chosen by the African Union, one from Asia (South Korea), two from the civil society ( NGOs and communities of people living with the diseases) and one from the WHO.[8] | https://www.wikidoc.org/index.php/UNITAID | |
623dd702f5fcbff180281a093d0a81434f761dcd | wikidoc | UPF0488 | UPF0488
UPF0488 is a protein that in humans is encoded by the C8orf33 (Chromosome 8 Open Reading Frame 33) gene. Chromosome 8 open reading frame 33 (C8orf33) is a human protein-coding gene of currently unknown function.
# Tissue and subcellular distribution
The UPF0488 protein is expressed in low-moderate levels in most tissues with some exceptions. It is predicted to localize in the nucleus and mitochondrion, though several orthologs were also predicted to localize in the cytosol; additionally, there is experimental evidence showing that human C8orf33 may localize in the peroxisomes. The expression of this gene is up-regulated after lithium exposure. C8orf33 is significantly up regulated in breast cancer drug treatment.
# Post-translational modification
Several post-translational modifications including phosphorylation, methylation, and acetylation are predicted. Additionally, it has several post-translational modifications such as acetylation, methylation, phosphoprotein – this includes amino acid modifications (or modified residues) such as N-acetylalanine, omega-N-methylarginine, and phosphoserine).
# Gene
This gene has 5 transcripts (splice variants), 62 orthologues and is a member of 1 Ensembl protein family. This gene is a member of the Human CCDS set: CCDS34974.1 This gene is a member of the Human CCDS set: CCDS34974. C8orf33 expression profile revealed that this gene was over-expressed after lithium exposure.
C8orf33 (UPF0488) has 31 alternatively spliced exons which combine in 13 different transcript variants –X1 variant is the longest and seems to have the greatest identity. Human tissue RNA sequencing of UPF0488.
## Transcript
UPF0488 has 5 transcripts splice variants. In terms of common gene haplotype alleles, the frequency of haplotype is 96.3% for one variant site. The primary transcript is 3,593 bp while a similar variant is 1,666 bp. The mRNA secondary structure of 3’ and 5’ UTR’s indicate different fold energies. The 5’ UTR region contains a fold energy of -21.20 and consists of 54 bases, the energy of the bases is -0.393. The 3’UTR region contains a fold energy of -646.10, consisting of 1873 bases – while the energy of the bases is -0.345.
## Expression
According to microarray-assessed tissue expression analysis by NCBI GEO, the gene C8orf33 has average expression levels in most tissues save including thyroid gland and parathyroid gland. Expression seems to be low in the pancreas, small intestine and other digestive organs except the kidney which seems relatively higher.
Approximate expression patterns inferred from EST sources. Norway rat putative protein-coding gene. Represented by 30 ESTs from 20 cDNA libraries. EST representation biased toward fetus. Gene expression seems to increase in the obesity-resistant categories
## Promoter
The promoter region for c8orf33 covers 1191 base pairs of DNA and contains over 700 potential factor binding sites. Fifteen transcription factors with highly conserved binding sites across multiple species’ promoter regions for c8orf33 were selected and shown (see Annotated Promoter Section). CDF1(Cycling DOF Factor 1) physically interacts with FKF1, CDF1 protein is more stable in FKF1 mutants. Another transcription factor, transcription factor II B (TFIIB) is a general transcription factor that is involved in the formation of the RNA polymerase II preinitiation complex (PIC).
# Protein
The Isoelectric point of the protein (UPF0488) is 9.16, given a detailed analysis of isoelectric point according to different scales for individual proteins. The Net Charge had been determined using the values available from the Lehninger's Biochemistry book. The precursor protein has a molecular weight of approximately 24.9925 kDa. This is slightly greater than the average pI of 6.81 for the human proteome. It contains repeats from 149 to 166, and 167 to 186. However, the repeats contain a high degree of degeneracy.
UPF0488 is an alanine rich protein relative to other proteins and low in all other amino acids besides arginine, leucine, and proline.
# Homology and evolution
The evolutionary lineage of UPF0488 can be traced as distant as invertebrates with a rate of evolution greater than that of fibrinogen.
Graph shows divergence of UPF0488 in a given time scale compared to fibrinogen and cytochrome c. Analignment using the SDSC Biology Workbench gives a 27.7% match Danio rerio. The ALIGN calculates a global alignment of two sequences, giving a Global alignment score of 215.
The mRNA of UPF0488 has a very high level of degeneracy across organisms. Sequences of very low identity to the human mRNA could only be identified in closely related organisms. However, the protein had far more distant relatives, including several invertebrates. Protein alignments for Homo Sapien UPF0488 was performed using the San Diego Workbench; these alignments were performed against several different taxa including vertebrates such as mammalia, reptilia, aves and invertebrates such as insecta. The protein sequences for UPf0488 are very highly conserved amongst close relatives of homo sapiens such as Gorilla Gorilla Gorilla (Gorilla). The similarity in protein sequence is inversely proportional to divergence (MYA) (table of homologs).
# Function
C8orf33 activity was found to be associated with G protein-coupled receptor signaling pathway, neuroactive ligand-receptor interaction, calcium signaling pathway and the regulation of the actin cytoskeleton. The following substances interact with UPF0488: 7,8-dihydro-7,8-dihydroxybenzo(a)pyrene 9,10-oxide, benzo(a)pyrene, methotrexate, and vitamin E.
# Pathology
The expression of the UPF0488 gene increases after treatment with cephaloridine, a semisynthetic derivative of cephalosporin C that inhibits gluconeogenesis in both target (kidney) and non-target (liver) organs. | UPF0488
UPF0488 is a protein that in humans is encoded by the C8orf33 (Chromosome 8 Open Reading Frame 33) gene. Chromosome 8 open reading frame 33 (C8orf33) is a human protein-coding gene of currently unknown function.
# Tissue and subcellular distribution
The UPF0488 protein is expressed in low-moderate levels in most tissues with some exceptions.[1] It is predicted to localize in the nucleus and mitochondrion, though several orthologs were also predicted to localize in the cytosol; additionally, there is experimental evidence showing that human C8orf33 may localize in the peroxisomes. The expression of this gene is up-regulated after lithium exposure. C8orf33 is significantly up regulated in breast cancer drug treatment.[2]
# Post-translational modification
Several post-translational modifications including phosphorylation, methylation, and acetylation are predicted.[3] Additionally, it has several post-translational modifications such as acetylation, methylation, phosphoprotein – this includes amino acid modifications (or modified residues) such as N-acetylalanine, omega-N-methylarginine, and phosphoserine).[4]
# Gene
This gene has 5 transcripts (splice variants), 62 orthologues and is a member of 1 Ensembl protein family. This gene is a member of the Human CCDS set: CCDS34974.1[5] This gene is a member of the Human CCDS set: CCDS34974. C8orf33 expression profile revealed that this gene was over-expressed after lithium exposure.[6]
C8orf33 (UPF0488) has 31 alternatively spliced exons which combine in 13 different transcript variants –X1 variant is the longest and seems to have the greatest identity. Human tissue RNA sequencing of UPF0488.
## Transcript
UPF0488 has 5 transcripts splice variants. In terms of common gene haplotype alleles, the frequency of haplotype is 96.3% for one variant site. The primary transcript is 3,593 bp while a similar variant is 1,666 bp. The mRNA secondary structure of 3’ and 5’ UTR’s indicate different fold energies. The 5’ UTR region contains a fold energy of -21.20 and consists of 54 bases, the energy of the bases is -0.393. The 3’UTR region contains a fold energy of -646.10, consisting of 1873 bases – while the energy of the bases is -0.345.[7]
## Expression
According to microarray-assessed tissue expression analysis by NCBI GEO, the gene C8orf33 has average expression levels in most tissues save including thyroid gland and parathyroid gland. Expression seems to be low in the pancreas, small intestine and other digestive organs except the kidney which seems relatively higher.[7]
Approximate expression patterns inferred from EST sources. Norway rat putative protein-coding gene. Represented by 30 ESTs from 20 cDNA libraries. EST representation biased toward fetus. Gene expression seems to increase in the obesity-resistant categories
## Promoter
The promoter region for c8orf33 covers 1191 base pairs of DNA and contains over 700 potential factor binding sites. Fifteen transcription factors with highly conserved binding sites across multiple species’ promoter regions for c8orf33 were selected and shown (see Annotated Promoter Section). CDF1(Cycling DOF Factor 1) physically interacts with FKF1, CDF1 protein is more stable in FKF1 mutants.[8] Another transcription factor, transcription factor II B (TFIIB) is a general transcription factor that is involved in the formation of the RNA polymerase II preinitiation complex (PIC).[9]
# Protein
The Isoelectric point of the protein (UPF0488) is 9.16, given a detailed analysis of isoelectric point according to different scales for individual proteins. The Net Charge had been determined using the values available from the Lehninger's Biochemistry book. The precursor protein has a molecular weight of approximately 24.9925 kDa. This is slightly greater than the average pI of 6.81 for the human proteome. It contains repeats from 149 to 166, and 167 to 186. However, the repeats contain a high degree of degeneracy.[10]
UPF0488 is an alanine rich protein relative to other proteins and low in all other amino acids besides arginine, leucine, and proline.
# Homology and evolution
The evolutionary lineage of UPF0488 can be traced as distant as invertebrates with a rate of evolution greater than that of fibrinogen.
Graph shows divergence of UPF0488 in a given time scale compared to fibrinogen and cytochrome c. Analignment using the SDSC Biology Workbench gives a 27.7% match Danio rerio. The ALIGN calculates a global alignment of two sequences, giving a Global alignment score of 215.[11]
The mRNA of UPF0488 has a very high level of degeneracy across organisms. Sequences of very low identity to the human mRNA could only be identified in closely related organisms. However, the protein had far more distant relatives, including several invertebrates. Protein alignments for Homo Sapien UPF0488 was performed using the San Diego Workbench; these alignments were performed against several different taxa including vertebrates such as mammalia, reptilia, aves and invertebrates such as insecta. The protein sequences for UPf0488 are very highly conserved amongst close relatives of homo sapiens such as Gorilla Gorilla Gorilla (Gorilla). The similarity in protein sequence is inversely proportional to divergence (MYA) (table of homologs).
# Function
C8orf33 activity was found to be associated with G protein-coupled receptor signaling pathway, neuroactive ligand-receptor interaction, calcium signaling pathway and the regulation of the actin cytoskeleton. The following substances interact with UPF0488: 7,8-dihydro-7,8-dihydroxybenzo(a)pyrene 9,10-oxide, benzo(a)pyrene, methotrexate, and vitamin E.[12][13]
# Pathology
The expression of the UPF0488 gene increases after treatment with cephaloridine, a semisynthetic derivative of cephalosporin C that inhibits gluconeogenesis in both target (kidney) and non-target (liver) organs.[8] | https://www.wikidoc.org/index.php/UPF0488 | |
825496eba57a5c4a93565fb6af90984296b3b698 | wikidoc | UQCRFS1 | UQCRFS1
Ubiquinol-cytochrome c reductase, Rieske iron-sulfur polypeptide 1, also known as UQCRFS1, Rieske iron-sulfur (Fe-S) protein, Cytochrome b-c1 complex subunit 5, or Complex III subunit 5 is a protein which in humans is encoded by the UQCRFS1 gene. UQCRFS1 is a subunit of the respiratory chain protein Ubiquinol Cytochrome c Reductase (UQCR, Complex III or Cytochrome bc1 complex), which consists of the products of one mitochondrially encoded gene, MTCYTB (mitochondrial cytochrome b) and ten nuclear genes UQCRC1, UQCRC2, Cytochrome C1, UQCRFS1 (this protein, a type of Rieske protein), UQCRB,UQCRQ ("11kDa protein"), UQCRH (cyt c1 Hinge protein), UCRC ("cyt. c1 associated protein"), and UQCR ("Rieske-associated protein").
# Structure
UQCRFS1 is located on the q arm of chromosome 19 in position 12, has 2 exons, and spans 5,969 base pairs. The UQCRFS1 gene produces a 29.7 kDa protein composed of 274 amino acids. UQCRFS1 is a subunit of the respiratory chain protein Ubiquinol Cytochrome c Reductase (UQCR, Complex III or Cytochrome bc1 complex). The structure of the complex is a symmetric homodimer composed of one mitochondrial genome encoded cytochrome b subunit and ten other nucleus encoded subunits. The primary structure of UQCRFS1 from cDNA analysis is composed of a 78 amino acid long N-terminal extension sequence.
# Function
The UQCRFS1 gene encodes for an iron-sulfur protein, which is an essential subunit of the Ubiquinol Cytochrome c Reductase or Complex III in the mitochondrial respiratory chain.
Complex III is responsible for electron transfer from coenzyme Q to cytochrome c as well as the proton transfer from the extracellular matrix to the intermembrane space which leads to ATP-coupled electrochemical potential generation. Incorporation of the subunit UQCRFS1 is the second to last step in complex III assembly. Once it is incorporated, UQCRFS1 undergoes proteolytic processing, which is essential for the correct insertion into Complex III. Preventions of the insertion may occur due to UQCRFS1-derived fragments, leading to a loss of Complex III structure and function.
# Clinical significance
The UQCRFS1 gene has been shown to be involved in carcinogenesis of some cancers. It is mainly associated with more aggressive tumors, and results in the development of more aggressive phenotypes of breast cancers. The association was found with a grade 3 amplification of the UQCRFS1 gene. In addition, Acute myeloid leukemia (AML) has been found to be associated with the amplification of UQCRFS1 gene. In contrast, UQCRFS1 and complex III has been absent in renal cell carcinoma, though the mechanism is unknown.
# Interactions
In addition to co-complexes, UQCRFS1 has protein-protein interactions with UQCRB, BCS1L, COX6B1, UQCRQ, NDUFA9, and other proteins. | UQCRFS1
Ubiquinol-cytochrome c reductase, Rieske iron-sulfur polypeptide 1, also known as UQCRFS1, Rieske iron-sulfur (Fe-S) protein, Cytochrome b-c1 complex subunit 5, or Complex III subunit 5 is a protein which in humans is encoded by the UQCRFS1 gene.[1] UQCRFS1 is a subunit of the respiratory chain protein Ubiquinol Cytochrome c Reductase (UQCR, Complex III or Cytochrome bc1 complex), which consists of the products of one mitochondrially encoded gene, MTCYTB (mitochondrial cytochrome b) and ten nuclear genes UQCRC1, UQCRC2, Cytochrome C1, UQCRFS1 (this protein, a type of Rieske protein), UQCRB,UQCRQ ("11kDa protein"), UQCRH (cyt c1 Hinge protein), UCRC ("cyt. c1 associated protein"), and UQCR ("Rieske-associated protein").[2]
# Structure
UQCRFS1 is located on the q arm of chromosome 19 in position 12, has 2 exons, and spans 5,969 base pairs.[1] The UQCRFS1 gene produces a 29.7 kDa protein composed of 274 amino acids.[3][4] UQCRFS1 is a subunit of the respiratory chain protein Ubiquinol Cytochrome c Reductase (UQCR, Complex III or Cytochrome bc1 complex). The structure of the complex is a symmetric homodimer composed of one mitochondrial genome encoded cytochrome b subunit and ten other nucleus encoded subunits.[5] The primary structure of UQCRFS1 from cDNA analysis is composed of a 78 amino acid long N-terminal extension sequence.[6]
# Function
The UQCRFS1 gene encodes for an iron-sulfur protein, which is an essential subunit of the Ubiquinol Cytochrome c Reductase or Complex III in the mitochondrial respiratory chain.[7]
Complex III is responsible for electron transfer from coenzyme Q to cytochrome c as well as the proton transfer from the extracellular matrix to the intermembrane space which leads to ATP-coupled electrochemical potential generation. Incorporation of the subunit UQCRFS1 is the second to last step in complex III assembly.[8] Once it is incorporated, UQCRFS1 undergoes proteolytic processing, which is essential for the correct insertion into Complex III. Preventions of the insertion may occur due to UQCRFS1-derived fragments, leading to a loss of Complex III structure and function.[2][8]
# Clinical significance
The UQCRFS1 gene has been shown to be involved in carcinogenesis of some cancers. It is mainly associated with more aggressive tumors, and results in the development of more aggressive phenotypes of breast cancers. The association was found with a grade 3 amplification of the UQCRFS1 gene.[9] In addition, Acute myeloid leukemia (AML) has been found to be associated with the amplification of UQCRFS1 gene.[10] In contrast, UQCRFS1 and complex III has been absent in renal cell carcinoma, though the mechanism is unknown.[11]
# Interactions
In addition to co-complexes, UQCRFS1 has protein-protein interactions with UQCRB, BCS1L, COX6B1, UQCRQ, NDUFA9, and other proteins.[12] | https://www.wikidoc.org/index.php/UQCRFS1 | |
742f9050b009d2c43ad22aa11868b26ca8a5275f | wikidoc | UniProt | UniProt
# Overview
UniProt is the universal protein database, a central repository of protein data created by combining Swiss-Prot, TrEMBL and PIR. This makes it the world's most comprehensive resource on protein information.
# The UniProt Consortium
The UniProt Consortium comprises the European Bioinformatics Institute (EBI), the Swiss Institute of Bioinformatics (SIB), and the Protein Information Resource (PIR). EBI, located at the Wellcome Trust Genome Campus in Hinxton, UK, hosts a large resource of bioinformatics databases and services. SIB, located in Geneva, Switzerland, maintains the ExPASy (Expert Protein Analysis System) servers that are a central resource for proteomics tools and databases. PIR, hosted by the National Biomedical Research Foundation (NBRF) at the Georgetown University Medical Center in Washington, DC, USA, is heir to the oldest protein sequence database, Margaret Dayhoff's Atlas of Protein Sequence and Structure. In 2002, EBI, SIB, and PIR joined forces as the UniProt Consortium.
# The Roots of UniProt Databases
Each consortium member is heavily involved in protein database maintenance and annotation. Until recently, EBI and SIB together produced Swiss-Prot and TrEMBL, while PIR produced the Protein Sequence Database (PIR-PSD). These databases coexisted with differing protein sequence coverage and annotation priorities. Swiss-Prot is recognized as the gold standard of protein annotation, with extensive cross-references, literature citations, and computational analyses provided by expert curators. Recognizing that sequence data were being generated at a pace exceeding Swiss-Prot's ability to keep up, TrEMBL (Translated EMBL Nucleotide Sequence Data Library) was created to provide automated annotations for those proteins not in Swiss-Prot. Meanwhile, PIR maintained the PIR-PSD and related databases, including iProClass, a database of protein sequences and curated families. The consortium members — all dedicated to the same goal of providing expansive and meaningful protein annotation, and all with solid foundations stemming from decades of activity — decided to pool their overlapping (and, importantly, their complementary) resources, efforts, and expertise. The UniProt databases build upon these solid foundations.
# Organization of UniProt Databases
The UniProt databases consist of three database layers:
- The UniProt Archive (UniParc) provides a stable, comprehensive sequence collection without redundant sequences by storing the complete body of publicly available protein sequence data.
- The UniProt Knowledgebase (UniProtKB) is the central database of protein sequences with accurate, consistent, and rich sequence and functional annotation.
- The UniProt Reference Clusters (UniRef) databases provide non-redundant reference data collections based on the UniProt knowledgebase in order to obtain complete coverage of sequence space at several resolutions.
# Funding for UniProt
UniProt is mainly supported by the National Institutes of Health (NIH) grant 1 U01 HG02712-01. Minor support for the EBI's involvement in UniProt comes from the two European Union contracts BioBabel (QLRT-2000-00981) and TEMBLOR (QLRI-2001-00015) and from the NIH grant 1R01HGO2273-01.
# External references
- ebi.uniprot.org
- pir.uniprot.org
- expasy.uniprot.org
- beta.uniprot.org (will replace the three sites listed above)
de:UniProt | UniProt
# Overview
UniProt is the universal protein database, a central repository of protein data created by combining Swiss-Prot, TrEMBL and PIR. This makes it the world's most comprehensive resource on protein information.
# The UniProt Consortium
The UniProt Consortium comprises the European Bioinformatics Institute (EBI), the Swiss Institute of Bioinformatics (SIB), and the Protein Information Resource (PIR). EBI, located at the Wellcome Trust Genome Campus in Hinxton, UK, hosts a large resource of bioinformatics databases and services. SIB, located in Geneva, Switzerland, maintains the ExPASy (Expert Protein Analysis System) servers that are a central resource for proteomics tools and databases. PIR, hosted by the National Biomedical Research Foundation (NBRF) at the Georgetown University Medical Center in Washington, DC, USA, is heir to the oldest protein sequence database, Margaret Dayhoff's Atlas of Protein Sequence and Structure. In 2002, EBI, SIB, and PIR joined forces as the UniProt Consortium.
# The Roots of UniProt Databases
Each consortium member is heavily involved in protein database maintenance and annotation. Until recently, EBI and SIB together produced Swiss-Prot and TrEMBL, while PIR produced the Protein Sequence Database (PIR-PSD). These databases coexisted with differing protein sequence coverage and annotation priorities. Swiss-Prot is recognized as the gold standard of protein annotation, with extensive cross-references, literature citations, and computational analyses provided by expert curators. Recognizing that sequence data were being generated at a pace exceeding Swiss-Prot's ability to keep up, TrEMBL (Translated EMBL Nucleotide Sequence Data Library) was created to provide automated annotations for those proteins not in Swiss-Prot. Meanwhile, PIR maintained the PIR-PSD and related databases, including iProClass, a database of protein sequences and curated families. The consortium members — all dedicated to the same goal of providing expansive and meaningful protein annotation, and all with solid foundations stemming from decades of activity — decided to pool their overlapping (and, importantly, their complementary) resources, efforts, and expertise. The UniProt databases build upon these solid foundations.
# Organization of UniProt Databases
The UniProt databases consist of three database layers:
- The UniProt Archive (UniParc) provides a stable, comprehensive sequence collection without redundant sequences by storing the complete body of publicly available protein sequence data.
- The UniProt Knowledgebase (UniProtKB) is the central database of protein sequences with accurate, consistent, and rich sequence and functional annotation.
- The UniProt Reference Clusters (UniRef) databases provide non-redundant reference data collections based on the UniProt knowledgebase in order to obtain complete coverage of sequence space at several resolutions.
# Funding for UniProt
UniProt is mainly supported by the National Institutes of Health (NIH) grant 1 U01 HG02712-01. Minor support for the EBI's involvement in UniProt comes from the two European Union contracts BioBabel (QLRT-2000-00981) and TEMBLOR (QLRI-2001-00015) and from the NIH grant 1R01HGO2273-01.
# External references
- ebi.uniprot.org
- pir.uniprot.org
- expasy.uniprot.org
- beta.uniprot.org (will replace the three sites listed above)
Template:Harvesternavi
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de:UniProt
Template:Jb1
Template:WH
Template:WikiDoc Sources | https://www.wikidoc.org/index.php/UniProt | |
a4f1d06a6b198caa0f65cb19dc809abea80b7d61 | wikidoc | Urachus | Urachus
# Overview
The urachus is an embryological canal connecting the urinary bladder of the fetus with the allantois, a structure that contributes to the formation of the umbilical cord. The lumen (inside) of the urachus is normally obliterated during embryonic development, transforming the urachus into a solid cord, a functionless remnant. The urachus lies in the space of Retzius, between the transversalis fascia anteriorly and the peritoneum posteriorly.
# Formation
The vesico-urethral portion of the urogenital sinus absorbs the ends of the Wolffian ducts and the associated ends of the renal diverticula, and these give rise to the trigone of the bladder and part of the prostatic urethra.
The remainder of the vesico-urethral portion forms the body of the bladder and part of the prostatic urethra; its apex is prolonged to the umbilicus as a narrow canal, which later is obliterated and becomes the median umbilical ligament (urachus).
Note: The two medial umbilical ligaments are the obliterated umbilical arteries.
# Pathology
Failure for the lumen of the urachus to be filled in leaves a patent (open) urachus. The telltale sign is leakage of urine through the umbilicus. A patent urachus needs to be surgically removed.
# Additional images
- Inguinal fossae | Urachus
Template:Infobox Embryology
# Overview
The urachus is an embryological canal connecting the urinary bladder of the fetus with the allantois, a structure that contributes to the formation of the umbilical cord. The lumen (inside) of the urachus is normally obliterated during embryonic development, transforming the urachus into a solid cord, a functionless remnant. The urachus lies in the space of Retzius, between the transversalis fascia anteriorly and the peritoneum posteriorly.
# Formation
The vesico-urethral portion of the urogenital sinus absorbs the ends of the Wolffian ducts and the associated ends of the renal diverticula, and these give rise to the trigone of the bladder and part of the prostatic urethra.
The remainder of the vesico-urethral portion forms the body of the bladder and part of the prostatic urethra; its apex is prolonged to the umbilicus as a narrow canal, which later is obliterated and becomes the median umbilical ligament (urachus).
Note: The two medial umbilical ligaments are the obliterated umbilical arteries.
# Pathology
Failure for the lumen of the urachus to be filled in leaves a patent (open) urachus. The telltale sign is leakage of urine through the umbilicus. A patent urachus needs to be surgically removed.
# Additional images
- Inguinal fossae
# External links
- Template:FPnotebook
- Template:EMedicineDictionary
- Template:EmbryologySwiss
- Persistent urachus at moorabbinvet.com.au
- Repair at pennhealth.com
Template:Gray's
de:Urachus
Template:WH
Template:WikiDoc Sources | https://www.wikidoc.org/index.php/Urachus | |
9bbeee176977b2f965165b91583473786954b5ee | wikidoc | Uranium | Uranium
Uranium (Template:PronEng) is a white/black metallic chemical element in the actinide series of the periodic table that has the symbol U and atomic number 92. It has 92 protons and electrons, 6 of them valence electrons. It can have between 141 and 146 neutrons, with 143 and 146 in its most common isotopes. Uranium has the highest atomic weight of the naturally occurring elements. Uranium is approximately 70% more dense than lead and is weakly radioactive. It occurs naturally in low concentrations (a few parts per million) in soil, rock and water, and is commercially extracted from uranium-bearing minerals such as uraninite (see uranium mining).
In nature, uranium atoms exist as uranium-238 (99.284%), uranium-235 (0.711%), and a very small amount of uranium-234 (0.0058%). Uranium decays slowly by emitting an alpha particle. The half-life of uranium-238 is about 4.47 billion years and that of uranium-235 is 704 million years, making them useful in dating the age of the Earth (see uranium-thorium dating, uranium-lead dating and uranium-uranium dating). Along with thorium and plutonium, uranium is one of the three fissile elements, meaning it can easily break apart to become lighter elements. While uranium-238 has a small probability to fission spontaneously or when bombarded with fast neutrons, the much higher probability of uranium-235 and to a lesser degree uranium-233 to fission when bombarded with slow neutrons generates the heat in nuclear reactors used as a source of power, and provides the fissile material for nuclear weapons. Both uses rely on the ability of uranium to produce a sustained nuclear chain reaction. Depleted uranium (uranium-238) is used in kinetic energy penetrators and armor plating.
Uranium is used as a colorant in uranium glass, producing orange-red to lemon yellow hues. It was also used for tinting and shading in early photography. The 1789 discovery of uranium in the mineral pitchblende is credited to Martin Heinrich Klaproth, who named the new element after the planet Uranus. Eugène-Melchior Péligot was the first person to isolate the metal, and its radioactive properties were uncovered in 1896 by Antoine Becquerel. Research by Enrico Fermi and others starting in 1934 led to its use as a fuel in the nuclear power industry and in Little Boy, the first nuclear weapon used in war. An ensuing arms race during the Cold War between the United States and the Soviet Union produced tens of thousands of nuclear weapons that used enriched uranium and uranium-derived plutonium. The security of those weapons and their fissile material following the breakup of the Soviet Union in 1991 along with the legacy of nuclear testing and nuclear accidents is a concern for public health and safety.
# Characteristics
When refined, uranium is a silvery white, weakly radioactive metal, which is slightly softer than steel, strongly electropositive and a poor electrical conductor. It is malleable, ductile, and slightly paramagnetic. Uranium metal has very high density, being approximately 70% more dense than lead, but slightly less dense than gold.
Uranium metal reacts with nearly all nonmetallic elements and their compounds, with reactivity increasing with temperature. Hydrochloric and nitric acids dissolve uranium, but nonoxidizing acids attack the element very slowly. When finely divided, it can react with cold water; in air, uranium metal becomes coated with a dark layer of uranium oxide. Uranium in ores is extracted chemically and converted into uranium dioxide or other chemical forms usable in industry.
Uranium was the first element that was found to be fissile. Upon bombardment with slow neutrons, its uranium-235 isotope becomes a very short-lived uranium-236 isotope, which immediately divides into two smaller nuclei, releasing nuclear binding energy and more neutrons. If these neutrons are absorbed by other uranium-235 nuclei, a nuclear chain reaction occurs and, if there is nothing to absorb some neutrons and slow the reaction, the reaction is explosive. As little as 15 lb (7 kg) of uranium-235 can be used to make an atomic bomb. The first atomic bomb worked by this principle (nuclear fission).
# Applications
## Military
The major application of uranium in the military sector is in high-density penetrators. This ammunition consists of depleted uranium (DU) alloyed with 1–2% other elements. At high impact speed, the density, hardness, and flammability of the projectile enable destruction of heavily armored targets. Tank armor and the removable armor on combat vehicles are also hardened with depleted uranium (DU) plates. The use of DU became a contentious political-environmental issue after the use of DU munitions by the US, UK and other countries during wars in the Persian Gulf and the Balkans raised questions of uranium compounds left in the soil (see Gulf War Syndrome).
Depleted uranium is also used as a shielding material in some containers used to store and transport radioactive materials. Other uses of DU include counterweights for aircraft control surfaces, as ballast for missile re-entry vehicles and as a shielding material. Due to its high density, this material is found in inertial guidance devices and in gyroscopic compasses. DU is preferred over similarly dense metals due to its ability to be easily machined and cast as well as its relatively low cost. Counter to popular belief, the main risk of exposure to DU is chemical poisoning by uranium oxide rather than radioactivity (uranium being only a weak alpha emitter).
During the later stages of World War II, the entire Cold War, and to a much lesser extent afterwards, uranium was used as the fissile explosive material to produce nuclear weapons. Two major types of fission bombs were built: a relatively simple device that uses uranium-235 and a more complicated mechanism that uses uranium-238-derived plutonium-239. Later, a much more complicated and far more powerful fusion bomb that uses a plutonium-based device in a uranium casing to cause a mixture of tritium and deuterium to undergo nuclear fusion was built.
## Civilian
The main use of uranium in the civilian sector is to fuel commercial nuclear power plants; by the time it is completely fissioned, one kilogram of uranium can theoretically produce about 20 trillion joules of energy (20Template:E joules); as much electricity as 1500 tonnes of coal. Generally this is in the form of enriched uranium, which has been processed to have higher-than-natural levels of uranium-235 and can be used for a variety of purposes relating to nuclear fission.
Commercial nuclear power plants use fuel that is typically enriched to around 3% uranium-235, the CANDU reactor is the only commercial reactor capable of using unenriched uranium fuel. Fuel used for United States Navy reactors is typically highly enriched in uranium-235 (the exact values are classified). In a breeder reactor, uranium-238 can also be converted into plutonium through the following reaction: 238U(n, gamma) → 239U -(beta) → 239Np -(beta) → 239Pu.
Prior to the discovery of radiation, uranium was primarily used in small amounts for yellow glass and pottery dyes (such as uranium glass and in Fiestaware). Uranium was also used in photographic chemicals (esp. uranium nitrate as a toner), in lamp filaments, to improve the appearance of dentures, and in the leather and wood industries for stains and dyes. Uranium salts are mordants of silk or wool. Uranyl acetate and uranyl formate are used as stains in transmission electron microscopy, to increase the contrast of biological specimens in ultrathin sections and in negative staining of viruses, isolated cell organelles and macromolecules.
The discovery of the radioactivity of uranium ushered in additional scientific and practical uses of the element. The long half-life of the isotope uranium-238 (4.51Template:E years) makes it well-suited for use in estimating the age of the earliest igneous rocks and for other types of radiometric dating (including uranium-thorium dating and uranium-lead dating). Uranium metal is used for X-ray targets in the making of high-energy X-rays.
# History
## Pre-discovery use
The use of uranium in its natural oxide form dates back to at least the year 79, when it was used to add a yellow color to ceramic glazes. Yellow glass with 1% uranium oxide was found in a Roman villa on Cape Posillipo in the Bay of Naples, Italy by R. T. Gunther of the University of Oxford in 1912. Starting in the late Middle Ages, pitchblende was extracted from the Habsburg silver mines in Joachimsthal, Bohemia (now Jáchymov in the Czech Republic) and was used as a coloring agent in the local glassmaking industry. In the early 19th century, the world's only known source of uranium ores were these old mines.
## Discovery
The discovery of the element is credited to the German chemist Martin Heinrich Klaproth. While he was working in his experimental laboratory in Berlin in 1789, Klaproth was able to precipitate a yellow compound (likely sodium diuranate) by dissolving pitchblende in nitric acid and neutralizing the solution with sodium hydroxide. Klaproth mistakenly assumed the yellow substance was the oxide of a yet-undiscovered element and heated it with charcoal to obtain a black powder, which he thought was the newly discovered metal itself (in fact, that powder was an oxide of uranium). He named the newly discovered element after the planet Uranus, which had been discovered eight years earlier by William Herschel.
In 1841, Eugène-Melchior Péligot, who was Professor of Analytical Chemistry at the Conservatoire National des Arts et Métiers (Central School of Arts and Manufactures) in Paris, isolated the first sample of uranium metal by heating uranium tetrachloride with potassium. Uranium was not seen as being particularly dangerous during much of the 19th century, leading to the development of various uses for the element. One such use for the oxide was the aforementioned but no longer secret coloring of pottery and glass.
Antoine Henri Becquerel discovered radioactivity by using uranium in 1896. Becquerel made the discovery in Paris by leaving a sample of a uranium salt on top of an unexposed photographic plate in a drawer and noting that the plate had become 'fogged'. He determined that a form of invisible light or rays emitted by uranium had exposed the plate.
## Fission research
A team led by Enrico Fermi in 1934 observed that bombarding uranium with neutrons produces the emission of beta rays (electrons or positrons; see beta particle). The fission products were at first mistaken for new elements of atomic numbers 93 and 94, which the Dean of the Faculty of Rome, Orso Mario Corbino, christened ausonium and hesperium, respectively. The experiments leading to the discovery of uranium's ability to fission (break apart) into lighter elements and release binding energy were conducted by Otto Hahn and Fritz Strassmann in Hahn's laboratory in Berlin. Lise Meitner and her nephew, physicist Otto Robert Frisch, published the physical explanation in February 1939 and named the process 'nuclear fission'. Soon after, Fermi hypothesized that the fission of uranium might release enough neutrons to sustain a fission reaction. Confirmation of this hypothesis came in 1939, and later work found that on average about 2 1/2 neutrons are released by each fission of the rare uranium isotope uranium-235. Further work found that the far more common uranium-238 isotope can be transmuted into plutonium, which, like uranium-235, is also fissionable by thermal neutrons.
On 2 December 1942, another team led by Enrico Fermi was able to initiate the first artificial nuclear chain reaction, Chicago Pile-1. Working in a lab below the stands of Stagg Field at the University of Chicago, the team created the conditions needed for such a reaction by piling together 400 tons (360 tonnes) of graphite, 58 tons (53 tonnes) of uranium oxide, and six tons (five and a half tonnes) of uranium metal. Later researchers found that such a chain reaction could either be controlled to produce usable energy or could be allowed to go out of control to produce an explosion more violent than anything possible using chemical explosives.
## Bombs and reactors
Two major types of atomic bomb were developed in the Manhattan Project during World War II: a plutonium-based device (see Trinity test and 'Fat Man') whose plutonium was derived from uranium-238, and a uranium-based device (nicknamed 'Little Boy') whose fissile material was highly enriched uranium. The uranium-based Little Boy device became the first nuclear weapon used in war when it was detonated over the Japanese city of Hiroshima on 6 August 1945. Exploding with a yield equivalent to 12,500 tonnes of TNT, the blast and thermal wave of the bomb destroyed nearly 50,000 buildings and killed approximately 75,000 people (see Atomic bombings of Hiroshima and Nagasaki).
Experimental Breeder Reactor I at the Idaho National Laboratory(INL) near Arco, Idaho became the first functioning artificial nuclear reactor on 20 December 1951. Initially, four 150-watt light bulbs were lit by the reactor, but improvements eventually enabled it to power the whole facility (later, the whole town of Arco became the first in the world to have all its electricity come from nuclear power). The world's first commercial scale nuclear power station, Obninsk in the Soviet Union, began generation with its reactor AM-1 on 27 June 1954. Other early nuclear power plants were Calder Hall in England which began generation on 17 October 1956 and the Shippingport Atomic Power Station in Pennsylvania which began on 26 May 1958. Nuclear power was used for the first time for propulsion by a submarine, the USS Nautilus, in 1954.
Fifteen ancient and no longer active natural nuclear fission reactors were found in three separate ore deposits at the Oklo mine in Gabon, West Africa in 1972. Discovered by French physicist Francis Perrin, they are collectively known as the Oklo Fossil Reactors. The ore they exist in is 1.7 billion years old; at that time, uranium-235 constituted about three percent of the total uranium on Earth. This is high enough to permit a sustained nuclear fission chain reaction to occur, providing other conditions are right. The ability of the surrounding sediment to contain the nuclear waste products in less than ideal conditions has been cited by the U.S. federal government as evidence of their claim that the Yucca Mountain facility could safely be a repository of waste for the nuclear power industry.
## Cold War legacy and waste
During the Cold War between the Soviet Union and the United States, huge stockpiles of uranium were amassed and tens of thousands of nuclear weapons were created using enriched uranium and plutonium made from uranium.
Since the break-up of the Soviet Union in 1991, an estimated 600 tons (540 tonnes) of highly-enriched weapons grade uranium (enough to make 40,000 nuclear warheads) have been stored in often inadequately guarded facilities in the Russian Federation and several other former Soviet states. Police in Asia, Europe, and South America on at least 16 occasions from 1993 to 2005 have intercepted shipments of smuggled bomb-grade uranium or plutonium, most of which was from ex-Soviet sources. From 1993 to 2005 the Material Protection, Control, and Accounting Program, operated by the federal government of the United States, spent approximately US $550 million to help safeguard uranium and plutonium stockpiles in Russia. The improvements made provided repairs and security enhancements at research and storage facilities. Scientific American reported in February of 2006 that some of the facilities had been protected only by chain link fences which were in severe states of disrepair. According to an interview from the article, one facility had been storing samples of enriched (weapons grade) uranium in a broom closet prior to the improvement project; another had been keeping track of its stock of nuclear warheads using index cards kept in a shoe box.
Above-ground nuclear tests by the Soviet Union and the United States in the 1950s and early 1960s and by France into the 1970s and 1980s spread a significant amount of fallout from uranium daughter isotopes around the world. Additional fallout and pollution occurred from several nuclear accidents.
The Windscale fire at the Sellafield nuclear plant in 1957 spread iodine-131, a short lived radioactive isotope, over much of Northern England.
The Three Mile Island accident in 1979 released a small amount of iodine-131. The amounts released by the partial meltdown of the Three Mile Island power plant were minimal, and an environmental survey only found trace amounts in a few field mice dwelling nearby. As I-131 has a half life of slightly more than eight days, any danger posed by the radioactive material has long since passed for both of these incidents.
The Chernobyl disaster in 1986, however, was a complete core breach meltdown and partial detonation of the reactor, which ejected iodine-131 and strontium-90 over a large area of Europe. The 28 year half-life of strontium-90 means that only recently has some of the surrounding countryside around the reactor been deemed safe enough to be habitable.
# Occurrence
## Biotic and abiotic
Uranium is a naturally occurring element that can be found in low levels within all rock, soil, and water. Uranium is also the highest-numbered element to be found naturally in significant quantities on earth and is always found combined with other elements. Along with all elements having atomic weights higher than that of iron, it is only naturally formed in supernova explosions. The decay of uranium, thorium and potassium-40 in the Earth's mantle is thought to be the main source of heat that keeps the outer core liquid and drives mantle convection, which in turn drives plate tectonics.
Its average concentration in the Earth's crust is (depending on the reference) 2 to 4 parts per million, or about 40 times as abundant as silver. The Earth's crust from the surface to 25 km (15 mi) down is calculated to contain 1017 kg (2Template:E lb) of uranium while the oceans may contain 1013 kg (2Template:E lb). The concentration of uranium in soil ranges from 0.7 to 11 parts per million (up to 15 parts per million in farmland soil due to use of phosphate fertilizers), and 3 parts per billion of sea water is composed of the element.
It is more plentiful than antimony, tin, cadmium, mercury, or silver, and it is about as abundant as arsenic or molybdenum. It is found in hundreds of minerals including uraninite (the most common uranium ore), autunite, uranophane, torbernite, and coffinite. Significant concentrations of uranium occur in some substances such as phosphate rock deposits, and minerals such as lignite, and monazite sands in uranium-rich ores (it is recovered commercially from these sources with as little as 0.1% uranium).
Some organisms, such as the lichen Trapelia involuta or microorganisms such as the bacterium Citrobacter, can absorb concentrations of uranium that are up to 300 times higher than in their environment. Citrobacter species absorb uranyl ions when given glycerol phosphate (or other similar organic phosphates). After one day, one gram of bacteria will encrust themselves with nine grams of uranyl phosphate crystals; this creates the possibility that these organisms could be used in bioremediation to decontaminate uranium-polluted water.
Plants absorb some uranium from the soil they are rooted in. Dry weight concentrations of uranium in plants range from 5 to 60 parts per billion, and ash from burnt wood can have concentrations up to 4 parts per million. Dry weight concentrations of uranium in food plants are typically lower with one to two micrograms per day ingested through the food people eat.
## Production and mining
Uranium ore is mined in several ways: by open pit, underground, in-situ leaching, and borehole mining (see uranium mining). Low-grade uranium ore typically contains 0.1 to 0.25% of actual uranium oxides, so extensive measures must be employed to extract the metal from its ore. High-grade ores found in Athabasca Basin deposits in Saskatchewan, Canada can contain up to 70% uranium oxides, and therefore must be diluted with waste rock prior to milling. Uranium ore is crushed and rendered into a fine powder and then leached with either an acid or alkali. The leachate is then subjected to one of several sequences of precipitation, solvent extraction, and ion exchange. The resulting mixture, called yellowcake, contains at least 75% uranium oxides. Yellowcake is then calcined to remove impurities from the milling process prior to refining and conversion.
Commercial-grade uranium can be produced through the reduction of uranium halides with alkali or alkaline earth metals. Uranium metal can also be made through electrolysis of KUF5 or UF4, dissolved in a molten calcium chloride (CaCl2) and sodium chloride (NaCl) solution. Very pure uranium can be produced through the thermal decomposition of uranium halides on a hot filament.
## Resources and reserves
It is estimated that 4.7 million tonnes of uranium ore reserves are economically viable, while 35 million tonnes are classed as mineral resources (reasonable prospects for eventual economic
extraction). An additional 4.6 billion tonnes of uranium are estimated to be in sea water (Japanese scientists in the 1980s showed that extraction of uranium from sea water using ion exchangers was feasible).
Exploration for uranium is continuing to increase with US$200 million being spent world wide in 2005, a 54% increase on the previous year.
Australia has 40% of the world's uranium ore reserves and the world's largest single uranium deposit, located at the Olympic Dam Mine in South Australia. Almost all of the uranium production is exported, under strict International Atomic Energy Agency safeguards against use in nuclear weapons.
The largest single source of uranium ore in the United States was the Colorado Plateau located in Colorado, Utah, New Mexico, and Arizona. The U.S. federal government paid discovery bonuses and guaranteed purchase prices to anyone who found and delivered uranium ore, and was the sole legal purchaser of the uranium. The economic incentives resulted in a frenzy of exploration and mining activity throughout the Colorado Plateau from 1947 through 1959 that left thousands of miles of crudely graded roads spider-webbing the remote deserts of the Colorado Plateau, and thousands of abandoned uranium mines, exploratory shafts, and tailings piles. The frenzy ended as suddenly as it had begun, when the U.S. government stopped purchasing the uranium.
## Supply
In 2005, seventeen countries produced concentrated uranium oxides, with Canada (27.9% of world production) and Australia (22.8%) being the largest producers and Kazakhstan (10.5%), Russia (8.0%), Namibia (7.5%), Niger (7.4%), Uzbekistan (5.5%), the United States (2.5%), Ukraine (1.9%) and China (1.7%) also producing significant amounts. The ultimate supply of uranium is believed to be very large and sufficient for at least the next 85 years although some studies indicate underinvestment in the late twentieth century may produce supply problems in the 21st century. It is estimated that for a ten times increase in price, the supply of uranium that can be economically mined is increased 300 times.
# Compounds
## Oxidation states and oxides
### Oxides
Calcined uranium yellowcake as produced in many large mills contains a distribution of uranium oxidation species in various forms ranging from most oxidized to least oxidized. Particles with short residence times in a calciner will generally be less oxidized than particles that have long retention times or are recovered in the stack scrubber. While uranium content is referred to for U3O8 content, to do so is inaccurate and dates to the days of the Manhattan project when U3O8 was used as an analytical chemistry reporting standard.
Phase relationships in the uranium-oxygen system are highly complex. The most important oxidation states of uranium are uranium(IV) and uranium(VI), and their two corresponding oxides are, respectively, uranium dioxide (UO2) and uranium trioxide (UO3). Other uranium oxides such as uranium monoxide (UO), diuranium pentoxide (U2O5), and uranium peroxide (UO42H2O) are also known to exist.
The most common forms of uranium oxide are triuranium octaoxide (U3O8) and the aforementioned UO2. Both oxide forms are solids that have low solubility in water and are relatively stable over a wide range of environmental conditions. Triuranium octaoxide is (depending on conditions) the most stable compound of uranium and is the form most commonly found in nature. Uranium dioxide is the form in which uranium is most commonly used as a nuclear reactor fuel. At ambient temperatures, UO2 will gradually convert to U3O8. Because of their stability, uranium oxides are generally considered the preferred chemical form for storage or disposal.
### Aqueous chemistry
Ions that represent the four different oxidation states of uranium are soluble and therefore can be studied in aqueous solutions. They are: U3+ (red), U4+ (green), UO+2 (unstable), and UO22+ (yellow). A few solid and semi-metallic compounds such as UO and US exist for the formal oxidation state uranium(II), but no simple ions are known to exist in solution for that state. Ions of U3+ liberate hydrogen from water and are therefore considered to be highly unstable. The UO2+2 ion represents the uranium(VI) state and is known to form compounds such as the carbonate, chloride and sulfate. UO2+2 also forms complexes with various organic chelating agents, the most commonly-encountered of which is uranyl acetate.
### Carbonates
The interactions of carbonate anions with uranium(VI) cause the Pourbaix diagram to change greatly when the medium is changed from water to a carbonate containing solution. It is interesting to note that while the vast majority of carbonates are insoluble in water (students are often taught that all carbonates other than those of alkali metals are insoluble in water), uranium carbonates are often soluble in water. This is due to the fact that a U(VI) cation is able to bind two terminal oxides and three or more carbonates to form anionic complexes.
The fraction digrams explain this further, it can be seen that when the pH of a uranium(VI) solution is increased that the uranium is converted to a hydrated uranium oxide hydroxide and then at high pHs to an anionic hydroxide complex.
On addition of carbonate to the system the uranium is converted to a series of carbonate complexes when the pH is increased, one important overall effect of these reactions is to increase the solubility of the uranium in the range pH 6 to 8. This is important when considering the long term stability of used uranium dioxide nuclear fuels.
## Hydrides, carbides and nitrides
Uranium metal heated to 250 to 300 °C (482 to 572 °F) reacts with hydrogen to form uranium hydride. Even higher temperatures will reversibly remove the hydrogen. This property makes uranium hydrides convenient starting materials to create reactive uranium powder along with various uranium carbide, nitride, and halide compounds. Two crystal modifications of uranium hydride exist: an α form that is obtained at low temperatures and a β form that is created when the formation temperature is above 250 °C.
Uranium carbides and uranium nitrides are both relatively inert semimetallic compounds that are minimally soluble in acids, react with water, and can ignite in air to form U3O8. Carbides of uranium include uranium monocarbide (UC), uranium dicarbide (UC2), and diuranium tricarbide (U2C3). Both UC and UC2 are formed by adding carbon to molten uranium or by exposing the metal to carbon monoxide at high temperatures. Stable below 1800 °C, U2C3 is prepared by subjecting a heated mixture of UC and UC2 to mechanical stress. Uranium nitrides obtained by direct exposure of the metal to nitrogen include uranium mononitride (UN), uranium dinitride (UN2), and diuranium trinitride (U2N3).
## Halides
All uranium fluorides are created using uranium tetrafluoride (UF4); UF4 itself is prepared by hydrofluorination of uranium dioxide. Reduction of UF4 with hydrogen at 1000 °C produces uranium trifluoride (UF3). Under the right conditions of temperature and pressure, the reaction of solid UF4 with gaseous uranium hexafluoride (UF6) can form the intermediate fluorides of U2F9, U4F17, and UF5.
At room temperatures, UF6 has a high vapor pressure, making it useful in the gaseous diffusion process to separate highly valuable uranium-235 from the far more common uranium-238 isotope. This compound can be prepared from uranium dioxide and uranium hydride by the following process:
UO2 + 4HF + heat (500 °C) → UF4 + 2H2O
UF4 + F2 + heat (350 °C) → UF6
The resulting UF6 white solid is highly reactive (by fluorination), easily sublimes (emitting a nearly perfect gas vapor), and is the most volatile compound of uranium known to exist.
One method of preparing uranium tetrachloride (UCl4) is to directly combine chlorine with either uranium metal or uranium hydride. The reduction of UCl4 by hydrogen produces uranium trichloride (UCl3) while the higher chlorides of uranium are prepared by reaction with additional chlorine. All uranium chlorides react with water and air.
Bromides and iodides of uranium are formed by direct reaction of, respectively, bromine and iodine with uranium or by adding UH3 to those element's acids. Known examples include: UBr3, UBr4, UI3, and UI4. Uranium oxyhalides are water-soluble and include UO2F2, UOCl2, UO2Cl2, and UO2Br2. Stability of the oxyhalides decrease as the atomic weight of the component halide increases.
# Isotopes
## Natural concentrations
Naturally occurring uranium is composed of three major isotopes, uranium-238 (99.28% natural abundance), uranium-235 (0.71%), and uranium-234 (0.0054%). All three isotopes are radioactive, creating radioisotopes, with the most abundant and stable being uranium-238 with a half-life of 4.51Template:E years (close to the age of the Earth), uranium-235 with a half-life of 7.13Template:E years, and uranium-234 with a half-life of 2.48Template:E years.
Uranium-238 is an α emitter, decaying through the 18-member uranium natural decay series into lead-206. The decay series of uranium-235 (also called actino-uranium) has 15 members that ends in lead-207, protactinium-231 and actinium-227. The constant rates of decay in these series makes comparison of the ratios of parent to daughter elements useful in radiometric dating. Uranium-233 is made from thorium-232 by neutron bombardment.
The isotope uranium-235 is important for both nuclear reactors and nuclear weapons because it is the only isotope existing in nature to any appreciable extent that is fissile, that is, can be broken apart by thermal neutrons. The isotope uranium-238 is also important because it absorbs neutrons to produce a radioactive isotope that subsequently decays to the isotope plutonium-239, which also is fissile.
## Enrichment
Enrichment of uranium ore through isotope separation to concentrate the fissionable uranium-235 is needed for use in nuclear weapons and most nuclear power plants with the exception of pressurised heavy water reactors. A majority of neutrons released by a fissioning atom of uranium-235 must impact other uranium-235 atoms to sustain the nuclear chain reaction needed for these applications. The concentration and amount of uranium-235 needed to achieve this is called a 'critical mass.'
To be considered 'enriched', the uranium-235 fraction has to be increased to significantly greater than its concentration in naturally-occurring uranium. Enriched uranium typically has a uranium-235 concentration of between 3 and 5%. The process produces huge quantities of uranium that is depleted of uranium-235 and with a correspondingly increased fraction of uranium-238, called depleted uranium or 'DU'. To be considered 'depleted', the uranium-235 isotope concentration has to have been decreased to significantly less than its natural concentration. Typically the amount of uranium-235 left in depleted uranium is 0.2% to 0.3%. As the price of uranium has risen since 2001, some enrichment tailings containing more than 0.35% uranium-235 are being considered for re-enrichment, driving the price of these depleted uranium hexafluoride stores above $130 per kilogram in July, 2007 from just $5 in 2001.
The gas centrifuge process, where gaseous uranium hexafluoride (UF6) is separated by the difference in molecular weight between 235UF6 and 238UF6 using high-speed centrifuges, has become the cheapest and leading enrichment process (lighter UF6 concentrates in the center of the centrifuge). The gaseous diffusion process was the previous leading method for enrichment and the one used in the Manhattan Project. In this process, uranium hexafluoride is repeatedly diffused through a silver-zinc membrane, and the different isotopes of uranium are separated by diffusion rate (uranium 238 is heavier and thus diffuses slightly slower than uranium-235). The molecular laser isotope separation method employs a laser beam of precise energy to sever the bond between uranium-235 and fluorine. This leaves uranium-238 bonded to fluorine and allows uranium-235 metal to precipitate from the solution. Another method is called liquid thermal diffusion.
# Precautions
## Exposure
A person can be exposed to uranium (or its radioactive daughters such as radon) by inhaling dust in air or by ingesting contaminated water and food. The amount of uranium in air is usually very small; however, people who work in factories that process phosphate fertilizers, live near government facilities that made or tested nuclear weapons, live or work near a modern battlefield where depleted uranium weapons have been used, or live or work near a coal-fired power plant, facilities that mine or process uranium ore, or enrich uranium for reactor fuel, may have increased exposure to uranium. Houses or structures that are over uranium deposits (either natural or man-made slag deposits) may have an increased incidence of exposure to radon gas.
Almost all uranium that is ingested is excreted during digestion, but up to 5% is absorbed by the body when the soluble uranyl ion is ingested while only 0.5% is absorbed when insoluble forms of uranium, such as its oxide, are ingested. However, soluble uranium compounds tend to quickly pass through the body whereas insoluble uranium compounds, especially when ingested via dust into the lungs, pose a more serious exposure hazard. After entering the bloodstream, the absorbed uranium tends to bioaccumulate and stay for many years in bone tissue because of uranium's affinity for phosphates. Uranium does not absorb through the skin, and alpha particles released by uranium cannot penetrate the skin.
## Effects
The greatest health risk from large intakes of uranium is toxic damage to the kidneys, because, in addition to being weakly radioactive, uranium is a toxic metal. Uranium is a reproductive toxicant. Radiological effects are generally local because this is the nature of alpha radiation, the primary form from U-238 decay. No human cancer has been seen as a result of exposure to natural or depleted uranium, but exposure to some of its decay products, especially radon, does pose a significant health threat. Exposure to strontium-90, iodine-131, and other fission products is unrelated to uranium exposure, but may result from medical procedures or exposure to spent reactor fuel or fallout from nuclear weapons.
Although accidental inhalation exposure to a high concentration of uranium hexafluoride has
resulted in human fatalities, those deaths were not associated with uranium itself. Finely-divided uranium metal presents a fire hazard because uranium is pyrophoric, so small grains will ignite spontaneously in air at room temperature. | Uranium
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Uranium (Template:PronEng) is a white/black metallic chemical element in the actinide series of the periodic table that has the symbol U and atomic number 92. It has 92 protons and electrons, 6 of them valence electrons. It can have between 141 and 146 neutrons, with 143 and 146 in its most common isotopes. Uranium has the highest atomic weight of the naturally occurring elements. Uranium is approximately 70% more dense than lead and is weakly radioactive. It occurs naturally in low concentrations (a few parts per million) in soil, rock and water, and is commercially extracted from uranium-bearing minerals such as uraninite (see uranium mining).
In nature, uranium atoms exist as uranium-238 (99.284%), uranium-235 (0.711%)[1], and a very small amount of uranium-234 (0.0058%). Uranium decays slowly by emitting an alpha particle. The half-life of uranium-238 is about 4.47 billion years and that of uranium-235 is 704 million years,[2] making them useful in dating the age of the Earth (see uranium-thorium dating, uranium-lead dating and uranium-uranium dating). Along with thorium and plutonium, uranium is one of the three fissile elements, meaning it can easily break apart to become lighter elements. While uranium-238 has a small probability to fission spontaneously or when bombarded with fast neutrons, the much higher probability of uranium-235 and to a lesser degree uranium-233 to fission when bombarded with slow neutrons generates the heat in nuclear reactors used as a source of power, and provides the fissile material for nuclear weapons. Both uses rely on the ability of uranium to produce a sustained nuclear chain reaction. Depleted uranium (uranium-238) is used in kinetic energy penetrators and armor plating.[3]
Uranium is used as a colorant in uranium glass, producing orange-red to lemon yellow hues. It was also used for tinting and shading in early photography. The 1789 discovery of uranium in the mineral pitchblende is credited to Martin Heinrich Klaproth, who named the new element after the planet Uranus. Eugène-Melchior Péligot was the first person to isolate the metal, and its radioactive properties were uncovered in 1896 by Antoine Becquerel. Research by Enrico Fermi and others starting in 1934 led to its use as a fuel in the nuclear power industry and in Little Boy, the first nuclear weapon used in war. An ensuing arms race during the Cold War between the United States and the Soviet Union produced tens of thousands of nuclear weapons that used enriched uranium and uranium-derived plutonium. The security of those weapons and their fissile material following the breakup of the Soviet Union in 1991 along with the legacy of nuclear testing and nuclear accidents is a concern for public health and safety.
# Characteristics
When refined, uranium is a silvery white, weakly radioactive metal, which is slightly softer than steel,[4] strongly electropositive and a poor electrical conductor.[5] It is malleable, ductile, and slightly paramagnetic.[4] Uranium metal has very high density, being approximately 70% more dense than lead, but slightly less dense than gold.
Uranium metal reacts with nearly all nonmetallic elements and their compounds, with reactivity increasing with temperature.[6] Hydrochloric and nitric acids dissolve uranium, but nonoxidizing acids attack the element very slowly.[5] When finely divided, it can react with cold water; in air, uranium metal becomes coated with a dark layer of uranium oxide.[4] Uranium in ores is extracted chemically and converted into uranium dioxide or other chemical forms usable in industry.
Uranium was the first element that was found to be fissile. Upon bombardment with slow neutrons, its uranium-235 isotope becomes a very short-lived uranium-236 isotope, which immediately divides into two smaller nuclei, releasing nuclear binding energy and more neutrons. If these neutrons are absorbed by other uranium-235 nuclei, a nuclear chain reaction occurs and, if there is nothing to absorb some neutrons and slow the reaction, the reaction is explosive. As little as 15 lb (7 kg) of uranium-235 can be used to make an atomic bomb.[7] The first atomic bomb worked by this principle (nuclear fission).
# Applications
## Military
The major application of uranium in the military sector is in high-density penetrators. This ammunition consists of depleted uranium (DU) alloyed with 1–2% other elements. At high impact speed, the density, hardness, and flammability of the projectile enable destruction of heavily armored targets. Tank armor and the removable armor on combat vehicles are also hardened with depleted uranium (DU) plates. The use of DU became a contentious political-environmental issue after the use of DU munitions by the US, UK and other countries during wars in the Persian Gulf and the Balkans raised questions of uranium compounds left in the soil (see Gulf War Syndrome).[7]
Depleted uranium is also used as a shielding material in some containers used to store and transport radioactive materials.[5] Other uses of DU include counterweights for aircraft control surfaces, as ballast for missile re-entry vehicles and as a shielding material.[4] Due to its high density, this material is found in inertial guidance devices and in gyroscopic compasses.[4] DU is preferred over similarly dense metals due to its ability to be easily machined and cast as well as its relatively low cost.[8] Counter to popular belief, the main risk of exposure to DU is chemical poisoning by uranium oxide rather than radioactivity (uranium being only a weak alpha emitter).
During the later stages of World War II, the entire Cold War, and to a much lesser extent afterwards, uranium was used as the fissile explosive material to produce nuclear weapons. Two major types of fission bombs were built: a relatively simple device that uses uranium-235 and a more complicated mechanism that uses uranium-238-derived plutonium-239. Later, a much more complicated and far more powerful fusion bomb that uses a plutonium-based device in a uranium casing to cause a mixture of tritium and deuterium to undergo nuclear fusion was built.[9]
## Civilian
The main use of uranium in the civilian sector is to fuel commercial nuclear power plants; by the time it is completely fissioned, one kilogram of uranium can theoretically produce about 20 trillion joules of energy (20Template:E joules); as much electricity as 1500 tonnes of coal.[3] Generally this is in the form of enriched uranium, which has been processed to have higher-than-natural levels of uranium-235 and can be used for a variety of purposes relating to nuclear fission.
Commercial nuclear power plants use fuel that is typically enriched to around 3% uranium-235,[3] the CANDU reactor is the only commercial reactor capable of using unenriched uranium fuel. Fuel used for United States Navy reactors is typically highly enriched in uranium-235 (the exact values are classified). In a breeder reactor, uranium-238 can also be converted into plutonium through the following reaction:[4] 238U(n, gamma) → 239U -(beta) → 239Np -(beta) → 239Pu.
Prior to the discovery of radiation, uranium was primarily used in small amounts for yellow glass and pottery dyes (such as uranium glass and in Fiestaware). Uranium was also used in photographic chemicals (esp. uranium nitrate as a toner),[4] in lamp filaments, to improve the appearance of dentures, and in the leather and wood industries for stains and dyes. Uranium salts are mordants of silk or wool. Uranyl acetate and uranyl formate are used as stains in transmission electron microscopy, to increase the contrast of biological specimens in ultrathin sections and in negative staining of viruses, isolated cell organelles and macromolecules.
The discovery of the radioactivity of uranium ushered in additional scientific and practical uses of the element. The long half-life of the isotope uranium-238 (4.51Template:E years) makes it well-suited for use in estimating the age of the earliest igneous rocks and for other types of radiometric dating (including uranium-thorium dating and uranium-lead dating). Uranium metal is used for X-ray targets in the making of high-energy X-rays.[4]
# History
## Pre-discovery use
The use of uranium in its natural oxide form dates back to at least the year 79, when it was used to add a yellow color to ceramic glazes.[4] Yellow glass with 1% uranium oxide was found in a Roman villa on Cape Posillipo in the Bay of Naples, Italy by R. T. Gunther of the University of Oxford in 1912.[10] Starting in the late Middle Ages, pitchblende was extracted from the Habsburg silver mines in Joachimsthal, Bohemia (now Jáchymov in the Czech Republic) and was used as a coloring agent in the local glassmaking industry.[11] In the early 19th century, the world's only known source of uranium ores were these old mines.
## Discovery
The discovery of the element is credited to the German chemist Martin Heinrich Klaproth. While he was working in his experimental laboratory in Berlin in 1789, Klaproth was able to precipitate a yellow compound (likely sodium diuranate) by dissolving pitchblende in nitric acid and neutralizing the solution with sodium hydroxide.[11] Klaproth mistakenly assumed the yellow substance was the oxide of a yet-undiscovered element and heated it with charcoal to obtain a black powder, which he thought was the newly discovered metal itself (in fact, that powder was an oxide of uranium).[11][12] He named the newly discovered element after the planet Uranus, which had been discovered eight years earlier by William Herschel.[13]
In 1841, Eugène-Melchior Péligot, who was Professor of Analytical Chemistry at the Conservatoire National des Arts et Métiers (Central School of Arts and Manufactures) in Paris, isolated the first sample of uranium metal by heating uranium tetrachloride with potassium.[14][11] Uranium was not seen as being particularly dangerous during much of the 19th century, leading to the development of various uses for the element. One such use for the oxide was the aforementioned but no longer secret coloring of pottery and glass.
Antoine Henri Becquerel discovered radioactivity by using uranium in 1896.[6] Becquerel made the discovery in Paris by leaving a sample of a uranium salt on top of an unexposed photographic plate in a drawer and noting that the plate had become 'fogged'.[15] He determined that a form of invisible light or rays emitted by uranium had exposed the plate.
## Fission research
A team led by Enrico Fermi in 1934 observed that bombarding uranium with neutrons produces the emission of beta rays (electrons or positrons; see beta particle).[16] The fission products were at first mistaken for new elements of atomic numbers 93 and 94, which the Dean of the Faculty of Rome, Orso Mario Corbino, christened ausonium and hesperium, respectively.[17][18][19][20] The experiments leading to the discovery of uranium's ability to fission (break apart) into lighter elements and release binding energy were conducted by Otto Hahn and Fritz Strassmann[16] in Hahn's laboratory in Berlin. Lise Meitner and her nephew, physicist Otto Robert Frisch, published the physical explanation in February 1939 and named the process 'nuclear fission'.[21] Soon after, Fermi hypothesized that the fission of uranium might release enough neutrons to sustain a fission reaction. Confirmation of this hypothesis came in 1939, and later work found that on average about 2 1/2 neutrons are released by each fission of the rare uranium isotope uranium-235.[16] Further work found that the far more common uranium-238 isotope can be transmuted into plutonium, which, like uranium-235, is also fissionable by thermal neutrons.
On 2 December 1942, another team led by Enrico Fermi was able to initiate the first artificial nuclear chain reaction, Chicago Pile-1. Working in a lab below the stands of Stagg Field at the University of Chicago, the team created the conditions needed for such a reaction by piling together 400 tons (360 tonnes) of graphite, 58 tons (53 tonnes) of uranium oxide, and six tons (five and a half tonnes) of uranium metal.[16] Later researchers found that such a chain reaction could either be controlled to produce usable energy or could be allowed to go out of control to produce an explosion more violent than anything possible using chemical explosives.
## Bombs and reactors
Two major types of atomic bomb were developed in the Manhattan Project during World War II: a plutonium-based device (see Trinity test and 'Fat Man') whose plutonium was derived from uranium-238, and a uranium-based device (nicknamed 'Little Boy') whose fissile material was highly enriched uranium. The uranium-based Little Boy device became the first nuclear weapon used in war when it was detonated over the Japanese city of Hiroshima on 6 August 1945. Exploding with a yield equivalent to 12,500 tonnes of TNT, the blast and thermal wave of the bomb destroyed nearly 50,000 buildings and killed approximately 75,000 people (see Atomic bombings of Hiroshima and Nagasaki).[15]
Experimental Breeder Reactor I at the Idaho National Laboratory(INL) near Arco, Idaho became the first functioning artificial nuclear reactor on 20 December 1951. Initially, four 150-watt light bulbs were lit by the reactor, but improvements eventually enabled it to power the whole facility (later, the whole town of Arco became the first in the world to have all its electricity come from nuclear power).[22] The world's first commercial scale nuclear power station, Obninsk in the Soviet Union, began generation with its reactor AM-1 on 27 June 1954. Other early nuclear power plants were Calder Hall in England which began generation on 17 October 1956[23] and the Shippingport Atomic Power Station in Pennsylvania which began on 26 May 1958. Nuclear power was used for the first time for propulsion by a submarine, the USS Nautilus, in 1954.[16]
Fifteen ancient and no longer active natural nuclear fission reactors were found in three separate ore deposits at the Oklo mine in Gabon, West Africa in 1972. Discovered by French physicist Francis Perrin, they are collectively known as the Oklo Fossil Reactors. The ore they exist in is 1.7 billion years old; at that time, uranium-235 constituted about three percent of the total uranium on Earth.[24] This is high enough to permit a sustained nuclear fission chain reaction to occur, providing other conditions are right. The ability of the surrounding sediment to contain the nuclear waste products in less than ideal conditions has been cited by the U.S. federal government as evidence of their claim that the Yucca Mountain facility could safely be a repository of waste for the nuclear power industry.[24]
## Cold War legacy and waste
During the Cold War between the Soviet Union and the United States, huge stockpiles of uranium were amassed and tens of thousands of nuclear weapons were created using enriched uranium and plutonium made from uranium.
Since the break-up of the Soviet Union in 1991, an estimated 600 tons (540 tonnes) of highly-enriched weapons grade uranium (enough to make 40,000 nuclear warheads) have been stored in often inadequately guarded facilities in the Russian Federation and several other former Soviet states.[7] Police in Asia, Europe, and South America on at least 16 occasions from 1993 to 2005 have intercepted shipments of smuggled bomb-grade uranium or plutonium, most of which was from ex-Soviet sources.[7] From 1993 to 2005 the Material Protection, Control, and Accounting Program, operated by the federal government of the United States, spent approximately US $550 million to help safeguard uranium and plutonium stockpiles in Russia.[7] The improvements made provided repairs and security enhancements at research and storage facilities. Scientific American reported in February of 2006 that some of the facilities had been protected only by chain link fences which were in severe states of disrepair. According to an interview from the article, one facility had been storing samples of enriched (weapons grade) uranium in a broom closet prior to the improvement project; another had been keeping track of its stock of nuclear warheads using index cards kept in a shoe box.[25]
Above-ground nuclear tests by the Soviet Union and the United States in the 1950s and early 1960s and by France into the 1970s and 1980s[8] spread a significant amount of fallout from uranium daughter isotopes around the world.[26] Additional fallout and pollution occurred from several nuclear accidents.
The Windscale fire at the Sellafield nuclear plant in 1957 spread iodine-131, a short lived radioactive isotope, over much of Northern England.
The Three Mile Island accident in 1979 released a small amount of iodine-131. The amounts released by the partial meltdown of the Three Mile Island power plant were minimal, and an environmental survey only found trace amounts in a few field mice dwelling nearby. As I-131 has a half life of slightly more than eight days, any danger posed by the radioactive material has long since passed for both of these incidents.
The Chernobyl disaster in 1986, however, was a complete core breach meltdown and partial detonation of the reactor, which ejected iodine-131 and strontium-90 over a large area of Europe. The 28 year half-life of strontium-90 means that only recently has some of the surrounding countryside around the reactor been deemed safe enough to be habitable.[8]
# Occurrence
## Biotic and abiotic
Uranium is a naturally occurring element that can be found in low levels within all rock, soil, and water. Uranium is also the highest-numbered element to be found naturally in significant quantities on earth and is always found combined with other elements.[4] Along with all elements having atomic weights higher than that of iron, it is only naturally formed in supernova explosions.[27] The decay of uranium, thorium and potassium-40 in the Earth's mantle is thought to be the main source of heat[28][29] that keeps the outer core liquid and drives mantle convection, which in turn drives plate tectonics.
Its average concentration in the Earth's crust is (depending on the reference) 2 to 4 parts per million,[5][8] or about 40 times as abundant as silver.[6] The Earth's crust from the surface to 25 km (15 mi) down is calculated to contain 1017 kg (2Template:E lb) of uranium while the oceans may contain 1013 kg (2Template:E lb).[5] The concentration of uranium in soil ranges from 0.7 to 11 parts per million (up to 15 parts per million in farmland soil due to use of phosphate fertilizers), and 3 parts per billion of sea water is composed of the element.[8]
It is more plentiful than antimony, tin, cadmium, mercury, or silver, and it is about as abundant as arsenic or molybdenum.[4][8] It is found in hundreds of minerals including uraninite (the most common uranium ore), autunite, uranophane, torbernite, and coffinite.[4] Significant concentrations of uranium occur in some substances such as phosphate rock deposits, and minerals such as lignite, and monazite sands in uranium-rich ores[4] (it is recovered commercially from these sources with as little as 0.1% uranium[6]).
Some organisms, such as the lichen Trapelia involuta or microorganisms such as the bacterium Citrobacter, can absorb concentrations of uranium that are up to 300 times higher than in their environment.[30] Citrobacter species absorb uranyl ions when given glycerol phosphate (or other similar organic phosphates). After one day, one gram of bacteria will encrust themselves with nine grams of uranyl phosphate crystals; this creates the possibility that these organisms could be used in bioremediation to decontaminate uranium-polluted water.[11][31]
Plants absorb some uranium from the soil they are rooted in. Dry weight concentrations of uranium in plants range from 5 to 60 parts per billion, and ash from burnt wood can have concentrations up to 4 parts per million.[11] Dry weight concentrations of uranium in food plants are typically lower with one to two micrograms per day ingested through the food people eat.[11]
## Production and mining
Uranium ore is mined in several ways: by open pit, underground, in-situ leaching, and borehole mining (see uranium mining).[3] Low-grade uranium ore typically contains 0.1 to 0.25% of actual uranium oxides, so extensive measures must be employed to extract the metal from its ore.[32] High-grade ores found in Athabasca Basin deposits in Saskatchewan, Canada can contain up to 70% uranium oxides, and therefore must be diluted with waste rock prior to milling. Uranium ore is crushed and rendered into a fine powder and then leached with either an acid or alkali. The leachate is then subjected to one of several sequences of precipitation, solvent extraction, and ion exchange. The resulting mixture, called yellowcake, contains at least 75% uranium oxides. Yellowcake is then calcined to remove impurities from the milling process prior to refining and conversion.
Commercial-grade uranium can be produced through the reduction of uranium halides with alkali or alkaline earth metals.[4] Uranium metal can also be made through electrolysis of KUF5 or UF4, dissolved in a molten calcium chloride (CaCl2) and sodium chloride (NaCl) solution.[4] Very pure uranium can be produced through the thermal decomposition of uranium halides on a hot filament.[4]
## Resources and reserves
It is estimated that 4.7 million tonnes of uranium ore reserves are economically viable, while 35 million tonnes are classed as mineral resources (reasonable prospects for eventual economic
extraction).[33] An additional 4.6 billion tonnes of uranium are estimated to be in sea water (Japanese scientists in the 1980s showed that extraction of uranium from sea water using ion exchangers was feasible).[34][35]
Exploration for uranium is continuing to increase with US$200 million being spent world wide in 2005, a 54% increase on the previous year.[33]
Australia has 40% of the world's uranium ore reserves[36] and the world's largest single uranium deposit, located at the Olympic Dam Mine in South Australia.[37] Almost all of the uranium production is exported, under strict International Atomic Energy Agency safeguards against use in nuclear weapons.
The largest single source of uranium ore in the United States was the Colorado Plateau located in Colorado, Utah, New Mexico, and Arizona. The U.S. federal government paid discovery bonuses and guaranteed purchase prices to anyone who found and delivered uranium ore, and was the sole legal purchaser of the uranium. The economic incentives resulted in a frenzy of exploration and mining activity throughout the Colorado Plateau from 1947 through 1959 that left thousands of miles of crudely graded roads spider-webbing the remote deserts of the Colorado Plateau, and thousands of abandoned uranium mines, exploratory shafts, and tailings piles. The frenzy ended as suddenly as it had begun, when the U.S. government stopped purchasing the uranium.
## Supply
In 2005, seventeen countries produced concentrated uranium oxides, with Canada (27.9% of world production) and Australia (22.8%) being the largest producers and Kazakhstan (10.5%), Russia (8.0%), Namibia (7.5%), Niger (7.4%), Uzbekistan (5.5%), the United States (2.5%), Ukraine (1.9%) and China (1.7%) also producing significant amounts.[38] The ultimate supply of uranium is believed to be very large and sufficient for at least the next 85 years[33] although some studies indicate underinvestment in the late twentieth century may produce supply problems in the 21st century.[39] It is estimated that for a ten times increase in price, the supply of uranium that can be economically mined is increased 300 times.[40]
# Compounds
## Oxidation states and oxides
### Oxides
Calcined uranium yellowcake as produced in many large mills contains a distribution of uranium oxidation species in various forms ranging from most oxidized to least oxidized. Particles with short residence times in a calciner will generally be less oxidized than particles that have long retention times or are recovered in the stack scrubber. While uranium content is referred to for U3O8 content, to do so is inaccurate and dates to the days of the Manhattan project when U3O8 was used as an analytical chemistry reporting standard.
Phase relationships in the uranium-oxygen system are highly complex. The most important oxidation states of uranium are uranium(IV) and uranium(VI), and their two corresponding oxides are, respectively, uranium dioxide (UO2) and uranium trioxide (UO3).[41] Other uranium oxides such as uranium monoxide (UO), diuranium pentoxide (U2O5), and uranium peroxide (UO4•2H2O) are also known to exist.
The most common forms of uranium oxide are triuranium octaoxide (U3O8) and the aforementioned UO2.[42] Both oxide forms are solids that have low solubility in water and are relatively stable over a wide range of environmental conditions. Triuranium octaoxide is (depending on conditions) the most stable compound of uranium and is the form most commonly found in nature. Uranium dioxide is the form in which uranium is most commonly used as a nuclear reactor fuel.[42] At ambient temperatures, UO2 will gradually convert to U3O8. Because of their stability, uranium oxides are generally considered the preferred chemical form for storage or disposal.[42]
### Aqueous chemistry
Ions that represent the four different oxidation states of uranium are soluble and therefore can be studied in aqueous solutions. They are: U3+ (red), U4+ (green), UO+2 (unstable), and UO22+ (yellow).[43] A few solid and semi-metallic compounds such as UO and US exist for the formal oxidation state uranium(II), but no simple ions are known to exist in solution for that state. Ions of U3+ liberate hydrogen from water and are therefore considered to be highly unstable. The UO2+2 ion represents the uranium(VI) state and is known to form compounds such as the carbonate, chloride and sulfate. UO2+2 also forms complexes with various organic chelating agents, the most commonly-encountered of which is uranyl acetate.[43]
### Carbonates
The interactions of carbonate anions with uranium(VI) cause the Pourbaix diagram to change greatly when the medium is changed from water to a carbonate containing solution. It is interesting to note that while the vast majority of carbonates are insoluble in water (students are often taught that all carbonates other than those of alkali metals are insoluble in water), uranium carbonates are often soluble in water. This is due to the fact that a U(VI) cation is able to bind two terminal oxides and three or more carbonates to form anionic complexes.
The fraction digrams explain this further, it can be seen that when the pH of a uranium(VI) solution is increased that the uranium is converted to a hydrated uranium oxide hydroxide and then at high pHs to an anionic hydroxide complex.
On addition of carbonate to the system the uranium is converted to a series of carbonate complexes when the pH is increased, one important overall effect of these reactions is to increase the solubility of the uranium in the range pH 6 to 8. This is important when considering the long term stability of used uranium dioxide nuclear fuels.
## Hydrides, carbides and nitrides
Uranium metal heated to 250 to 300 °C (482 to 572 °F) reacts with hydrogen to form uranium hydride. Even higher temperatures will reversibly remove the hydrogen. This property makes uranium hydrides convenient starting materials to create reactive uranium powder along with various uranium carbide, nitride, and halide compounds.[45] Two crystal modifications of uranium hydride exist: an α form that is obtained at low temperatures and a β form that is created when the formation temperature is above 250 °C.[45]
Uranium carbides and uranium nitrides are both relatively inert semimetallic compounds that are minimally soluble in acids, react with water, and can ignite in air to form U3O8.[45] Carbides of uranium include uranium monocarbide (UC), uranium dicarbide (UC2), and diuranium tricarbide (U2C3). Both UC and UC2 are formed by adding carbon to molten uranium or by exposing the metal to carbon monoxide at high temperatures. Stable below 1800 °C, U2C3 is prepared by subjecting a heated mixture of UC and UC2 to mechanical stress.[46] Uranium nitrides obtained by direct exposure of the metal to nitrogen include uranium mononitride (UN), uranium dinitride (UN2), and diuranium trinitride (U2N3).[46]
## Halides
All uranium fluorides are created using uranium tetrafluoride (UF4); UF4 itself is prepared by hydrofluorination of uranium dioxide.[45] Reduction of UF4 with hydrogen at 1000 °C produces uranium trifluoride (UF3). Under the right conditions of temperature and pressure, the reaction of solid UF4 with gaseous uranium hexafluoride (UF6) can form the intermediate fluorides of U2F9, U4F17, and UF5.[45]
At room temperatures, UF6 has a high vapor pressure, making it useful in the gaseous diffusion process to separate highly valuable uranium-235 from the far more common uranium-238 isotope. This compound can be prepared from uranium dioxide and uranium hydride by the following process:[45]
UO2 + 4HF + heat (500 °C) → UF4 + 2H2O
UF4 + F2 + heat (350 °C) → UF6
The resulting UF6 white solid is highly reactive (by fluorination), easily sublimes (emitting a nearly perfect gas vapor), and is the most volatile compound of uranium known to exist.[45]
One method of preparing uranium tetrachloride (UCl4) is to directly combine chlorine with either uranium metal or uranium hydride. The reduction of UCl4 by hydrogen produces uranium trichloride (UCl3) while the higher chlorides of uranium are prepared by reaction with additional chlorine.[45] All uranium chlorides react with water and air.
Bromides and iodides of uranium are formed by direct reaction of, respectively, bromine and iodine with uranium or by adding UH3 to those element's acids.[45] Known examples include: UBr3, UBr4, UI3, and UI4. Uranium oxyhalides are water-soluble and include UO2F2, UOCl2, UO2Cl2, and UO2Br2. Stability of the oxyhalides decrease as the atomic weight of the component halide increases.[45]
# Isotopes
## Natural concentrations
Naturally occurring uranium is composed of three major isotopes, uranium-238 (99.28% natural abundance), uranium-235 (0.71%), and uranium-234 (0.0054%). All three isotopes are radioactive, creating radioisotopes, with the most abundant and stable being uranium-238 with a half-life of 4.51Template:E years (close to the age of the Earth), uranium-235 with a half-life of 7.13Template:E years, and uranium-234 with a half-life of 2.48Template:E years.[47]
Uranium-238 is an α emitter, decaying through the 18-member uranium natural decay series into lead-206.[6] The decay series of uranium-235 (also called actino-uranium) has 15 members that ends in lead-207, protactinium-231 and actinium-227.[6] The constant rates of decay in these series makes comparison of the ratios of parent to daughter elements useful in radiometric dating. Uranium-233 is made from thorium-232 by neutron bombardment.[4]
The isotope uranium-235 is important for both nuclear reactors and nuclear weapons because it is the only isotope existing in nature to any appreciable extent that is fissile, that is, can be broken apart by thermal neutrons.[6] The isotope uranium-238 is also important because it absorbs neutrons to produce a radioactive isotope that subsequently decays to the isotope plutonium-239, which also is fissile.[16]
## Enrichment
Enrichment of uranium ore through isotope separation to concentrate the fissionable uranium-235 is needed for use in nuclear weapons and most nuclear power plants with the exception of pressurised heavy water reactors. A majority of neutrons released by a fissioning atom of uranium-235 must impact other uranium-235 atoms to sustain the nuclear chain reaction needed for these applications. The concentration and amount of uranium-235 needed to achieve this is called a 'critical mass.'
To be considered 'enriched', the uranium-235 fraction has to be increased to significantly greater than its concentration in naturally-occurring uranium. Enriched uranium typically has a uranium-235 concentration of between 3 and 5%.[48] The process produces huge quantities of uranium that is depleted of uranium-235 and with a correspondingly increased fraction of uranium-238, called depleted uranium or 'DU'. To be considered 'depleted', the uranium-235 isotope concentration has to have been decreased to significantly less than its natural concentration. Typically the amount of uranium-235 left in depleted uranium is 0.2% to 0.3%.[49] As the price of uranium has risen since 2001, some enrichment tailings containing more than 0.35% uranium-235 are being considered for re-enrichment, driving the price of these depleted uranium hexafluoride stores above $130 per kilogram in July, 2007 from just $5 in 2001.[49]
The gas centrifuge process, where gaseous uranium hexafluoride (UF6) is separated by the difference in molecular weight between 235UF6 and 238UF6 using high-speed centrifuges, has become the cheapest and leading enrichment process (lighter UF6 concentrates in the center of the centrifuge).[15] The gaseous diffusion process was the previous leading method for enrichment and the one used in the Manhattan Project. In this process, uranium hexafluoride is repeatedly diffused through a silver-zinc membrane, and the different isotopes of uranium are separated by diffusion rate (uranium 238 is heavier and thus diffuses slightly slower than uranium-235).[15] The molecular laser isotope separation method employs a laser beam of precise energy to sever the bond between uranium-235 and fluorine. This leaves uranium-238 bonded to fluorine and allows uranium-235 metal to precipitate from the solution.[3] Another method is called liquid thermal diffusion.[5]
# Precautions
## Exposure
A person can be exposed to uranium (or its radioactive daughters such as radon) by inhaling dust in air or by ingesting contaminated water and food. The amount of uranium in air is usually very small; however, people who work in factories that process phosphate fertilizers, live near government facilities that made or tested nuclear weapons, live or work near a modern battlefield where depleted uranium weapons have been used, or live or work near a coal-fired power plant, facilities that mine or process uranium ore, or enrich uranium for reactor fuel, may have increased exposure to uranium.[50][51] Houses or structures that are over uranium deposits (either natural or man-made slag deposits) may have an increased incidence of exposure to radon gas.
Almost all uranium that is ingested is excreted during digestion, but up to 5% is absorbed by the body when the soluble uranyl ion is ingested while only 0.5% is absorbed when insoluble forms of uranium, such as its oxide, are ingested.[11] However, soluble uranium compounds tend to quickly pass through the body whereas insoluble uranium compounds, especially when ingested via dust into the lungs, pose a more serious exposure hazard. After entering the bloodstream, the absorbed uranium tends to bioaccumulate and stay for many years in bone tissue because of uranium's affinity for phosphates.[11] Uranium does not absorb through the skin, and alpha particles released by uranium cannot penetrate the skin.
## Effects
The greatest health risk from large intakes of uranium is toxic damage to the kidneys, because, in addition to being weakly radioactive, uranium is a toxic metal.[52][53][11] Uranium is a reproductive toxicant.[54] Radiological effects are generally local because this is the nature of alpha radiation, the primary form from U-238 decay. No human cancer has been seen as a result of exposure to natural or depleted uranium,[55] but exposure to some of its decay products, especially radon, does pose a significant health threat.[8] Exposure to strontium-90, iodine-131, and other fission products is unrelated to uranium exposure, but may result from medical procedures or exposure to spent reactor fuel or fallout from nuclear weapons.[56]
Although accidental inhalation exposure to a high concentration of uranium hexafluoride has
resulted in human fatalities, those deaths were not associated with uranium itself.[57] Finely-divided uranium metal presents a fire hazard because uranium is pyrophoric, so small grains will ignite spontaneously in air at room temperature.[4] | https://www.wikidoc.org/index.php/Uranium | |
4b4a34a8495d7e6c77a3bc69b6fbbc9790da19a7 | wikidoc | Urology | Urology
Steven C. Campbell, M.D., Ph.D.
# Overview
Urology is the specialty of medicine that focuses on the urinary tracts of males and females, and on the reproductive system of males. Medical professionals specializing in the field of urology are called urologists and are trained to diagnose, treat, and manage patients with urological disorders. The organs covered by urology include the kidneys, ureters, urinary bladder, urethra, and the male reproductive organs (testes, epididymis, vas deferens, seminal vesicles, prostate and penis).
In men, the urinary system overlaps with the reproductive system, and in women the urinary tract opens into the vulva. In both sexes, the urinary and reproductive tracts are close together, and disorders of one often affect the other. Urology combines management of medical (i.e., non-surgical) problems such as urinary infections, and surgical problems such as the correction of congenital abnormalities and the surgical management of cancers. Such abnormalities within the genital region are called genitourinary disorders.
Urology is closely related to, and in some cases overlaps with, the medical fields of nephrology, andrology, gynecology, proctology and oncology.
# Branches of urology
As a discipline that involves the study of many organs and physiological systems, urology can be broken down into subfields. Many urologists, particularly those involved in research, choose an informal specialization in a particular field of urology.
- Neurourology involves the study of nervous system control of the genitourinary system, and of conditions causing abnormal urination. Neurological diseases and disorders such as multiple sclerosis, Parkinson's disease, and spinal cord injury can disrupt the lower urinary tract and result in conditions such as urinary incontinence, overactive bladder, urinary retention, and detrusor-sphincter dyssynergia. Less marked neurological abnormalities can cause urological disorders as well -- for example, abnormalities of the sensory nervous system are thought by many researchers to play a role in disorders of painful or frequent urination (e.g. interstitial cystitis). Urodynamic studies play an important diagnostic role in neurourology; urologists often use diagnostic techniques such as flow cystometry or ambulatory urodynamic profiles to determine the best method of treatment for the patient. Medical therapy for nervous system disorders includes drugs that target the nervous system and neuromodulation.
- Pediatric urology is the study of urologic disorders in children such as enuresis, hypospadias, vesicoureteral reflux, and antenatal hydronephrosis.
- Urologic oncology is the study of malignant genitourinary diseases such as prostate cancer and bladder cancer.
Other subfields of urology include stone disease, sexual dysfunction and male infertility. | Urology
Steven C. Campbell, M.D., Ph.D.
# Overview
Urology is the specialty of medicine that focuses on the urinary tracts of males and females, and on the reproductive system of males. Medical professionals specializing in the field of urology are called urologists and are trained to diagnose, treat, and manage patients with urological disorders. The organs covered by urology include the kidneys, ureters, urinary bladder, urethra, and the male reproductive organs (testes, epididymis, vas deferens, seminal vesicles, prostate and penis).
In men, the urinary system overlaps with the reproductive system, and in women the urinary tract opens into the vulva. In both sexes, the urinary and reproductive tracts are close together, and disorders of one often affect the other. Urology combines management of medical (i.e., non-surgical) problems such as urinary infections, and surgical problems such as the correction of congenital abnormalities and the surgical management of cancers. Such abnormalities within the genital region are called genitourinary disorders.
Urology is closely related to, and in some cases overlaps with, the medical fields of nephrology, andrology, gynecology, proctology and oncology.
# Branches of urology
As a discipline that involves the study of many organs and physiological systems, urology can be broken down into subfields. Many urologists, particularly those involved in research, choose an informal specialization in a particular field of urology.
- Neurourology involves the study of nervous system control of the genitourinary system, and of conditions causing abnormal urination. Neurological diseases and disorders such as multiple sclerosis, Parkinson's disease, and spinal cord injury can disrupt the lower urinary tract and result in conditions such as urinary incontinence, overactive bladder, urinary retention, and detrusor-sphincter dyssynergia. Less marked neurological abnormalities can cause urological disorders as well -- for example, abnormalities of the sensory nervous system are thought by many researchers to play a role in disorders of painful or frequent urination (e.g. interstitial cystitis).[1] Urodynamic studies play an important diagnostic role in neurourology; urologists often use diagnostic techniques such as flow cystometry or ambulatory urodynamic profiles to determine the best method of treatment for the patient. Medical therapy for nervous system disorders includes drugs that target the nervous system and neuromodulation.
- Pediatric urology is the study of urologic disorders in children such as enuresis, hypospadias, vesicoureteral reflux, and antenatal hydronephrosis.
- Urologic oncology is the study of malignant genitourinary diseases such as prostate cancer and bladder cancer.
Other subfields of urology include stone disease, sexual dysfunction and male infertility. | https://www.wikidoc.org/index.php/Urologic | |
a80d5c723e0c58833890f7caa3ce3b3e5b4bac68 | wikidoc | VO2 max | VO2 max
# Overview
VO2 max is the maximum capacity to transport and utilize oxygen during incremental exercise. (The derivation is V̇ - volume per time, O2 - oxygen, max - maximum). It is also called maximal oxygen consumption or maximal oxygen uptake. It is also known as aerobic capacity, which reflects the physical fitness of a person.
It is the maximal intake of oxygen that a person can take in at the moment of exhaustion, which is determined according to that person's age, height, weight, fitness level and basal metabolic rate.
Expressed either as an absolute rate in litres of oxygen per minute (l/min) or as a relative rate in millilitres of oxygen per kilogram of bodyweight per minute (ml/kg/min), the latter expression is often used to compare the performance of endurance sports athletes. A less size-biased measure is to divide by \sqrt{mass^2} rather than mass.
It has become a standard testing method for athletes, athletic and sportive people and even for airplane pilots, car race drivers, and individuals with jobs demanding them to be fit, in good shape and health. It is a part of cardiac and pulmonary screenings too.
# Measuring VO2 max
Accurately measuring VO2 max involves a physical effort sufficient in duration and intensity to fully tax the aerobic energy system. In general clinical and athletic testing, this usually involves a graded exercise test (either on a treadmill or on a cycle ergometer) in which exercise intensity is progressively increased while measuring ventilation and oxygen and carbon dioxide concentration of the inhaled and exhaled air. V̇O2 max is reached when oxygen consumption remains at steady state despite an increase in workload.
## Fick Equation
VO2 max is properly defined by the Fick Equation:
where Q is the cardiac output of the heart, CaO2 is the arterial oxygen content, and CvO2 is the venous oxygen content.
## Cooper test
Dr. Kenneth H. Cooper conducted a study for the United States Air Force in the late 1960s. One of the results of this was the Cooper test in which the distance covered running in 12 minutes is measured. An approximate estimate for VO2 max (in ml/min/kg) is:
where d12 is distance (in metres) covered in 12 minutes.
There are several other reliable tests and VO2 max calculators to estimate VO2 max.
# VO2 max Levels
VO2 max varies considerably in the population. The average young untrained male will have a VO2 max of approximately 3.5 litres/minute and 45 ml/min/kg. The average young untrained female will score a VO2 max of approximately 2.0 litres/minute and 38 ml/min/kg. These scores can improve with training and decrease with age, though the degree of trainability also varies very widely.
In sports where endurance is an important component in performance, such as cycling, rowing, cross-country skiing and running, world class athletes typically have high VO2 maximums. World class male athletes, cyclists and cross-country skiers typically exceed 80 ml/kg/min and a rare few may exceed 90 ml/kg/min for men and 70 ml/kg/min for women. Three time Tour de France winner Greg LeMond is reported to have had a VO2 max of 92.5 at his peak - one of the highest ever recorded, while cross-country skier Bjørn Dæhlie measured at an astounding 96 ml/kg/min. It should also be noted that Dæhlie's result was achieved out of season and that physiologist Erlend Hem who was responsible for the testing stated that he would not discount the possibility of the skier passing 100 ml/kg/min at his absolute peak. By comparison a competitive club athlete might achieve a VO2 max of around 70 ml/kg/min. World class rowers are physically very large endurance athletes and typically do not score as high on a per weight basis, but often score exceptionally high in absolute terms. Male rowers typically score VO2 maximums over 6 litres/minute, and some exceptional individuals have exceeded 8 l/min.
To put this into perspective, thoroughbred horses have a VO2 max of around 180 ml/min/kg. Siberian dogs running in the Iditarod Trail Sled Dog Race sled race have VO2 values as high as 240 ml/min/kg. | VO2 max
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Dayana Davidis, M.D. [2]
# Overview
VO2 max is the maximum capacity to transport and utilize oxygen during incremental exercise. (The derivation is V̇ - volume per time, O2 - oxygen, max - maximum). It is also called maximal oxygen consumption or maximal oxygen uptake. It is also known as aerobic capacity, which reflects the physical fitness of a person.
It is the maximal intake of oxygen that a person can take in at the moment of exhaustion, which is determined according to that person's age, height, weight, fitness level and basal metabolic rate.
Expressed either as an absolute rate in litres of oxygen per minute (l/min) or as a relative rate in millilitres of oxygen per kilogram of bodyweight per minute (ml/kg/min), the latter expression is often used to compare the performance of endurance sports athletes. A less size-biased measure is to divide by <math>\sqrt[3]{mass^2}</math> rather than mass.
It has become a standard testing method for athletes, athletic and sportive people and even for airplane pilots, car race drivers, and individuals with jobs demanding them to be fit, in good shape and health. It is a part of cardiac and pulmonary screenings too.
# Measuring VO2 max
Accurately measuring VO2 max involves a physical effort sufficient in duration and intensity to fully tax the aerobic energy system. In general clinical and athletic testing, this usually involves a graded exercise test (either on a treadmill or on a cycle ergometer) in which exercise intensity is progressively increased while measuring ventilation and oxygen and carbon dioxide concentration of the inhaled and exhaled air. V̇O2 max is reached when oxygen consumption remains at steady state despite an increase in workload.
## Fick Equation
VO2 max is properly defined by the Fick Equation:
where Q is the cardiac output of the heart, CaO2 is the arterial oxygen content, and CvO2 is the venous oxygen content.
## Cooper test
Dr. Kenneth H. Cooper conducted a study for the United States Air Force in the late 1960s. One of the results of this was the Cooper test in which the distance covered running in 12 minutes is measured. An approximate estimate for VO2 max (in ml/min/kg) is:
where d12 is distance (in metres) covered in 12 minutes.
There are several other reliable tests and VO2 max calculators to estimate VO2 max.
# VO2 max Levels
VO2 max varies considerably in the population. The average young untrained male will have a VO2 max of approximately 3.5 litres/minute and 45 ml/min/kg.[1] The average young untrained female will score a VO2 max of approximately 2.0 litres/minute and 38 ml/min/kg.[citation needed] These scores can improve with training and decrease with age, though the degree of trainability also varies very widely.[2][3]
In sports where endurance is an important component in performance, such as cycling, rowing, cross-country skiing and running, world class athletes typically have high VO2 maximums. World class male athletes, cyclists and cross-country skiers typically exceed 80 ml/kg/min and a rare few may exceed 90 ml/kg/min for men and 70 ml/kg/min for women. Three time Tour de France winner Greg LeMond is reported to have had a VO2 max of 92.5 at his peak - one of the highest ever recorded, while cross-country skier Bjørn Dæhlie measured at an astounding 96 ml/kg/min.[4] It should also be noted that Dæhlie's result was achieved out of season and that physiologist Erlend Hem who was responsible for the testing stated that he would not discount the possibility of the skier passing 100 ml/kg/min at his absolute peak. By comparison a competitive club athlete might achieve a VO2 max of around 70 ml/kg/min.[1] World class rowers are physically very large endurance athletes and typically do not score as high on a per weight basis, but often score exceptionally high in absolute terms. Male rowers typically score VO2 maximums over 6 litres/minute, and some exceptional individuals have exceeded 8 l/min.
To put this into perspective, thoroughbred horses have a VO2 max of around 180 ml/min/kg. Siberian dogs running in the Iditarod Trail Sled Dog Race sled race have VO2 values as high as 240 ml/min/kg.[5] | https://www.wikidoc.org/index.php/VO2_max | |
2759ef3574e8b60446533d9db349be7e15f41896 | wikidoc | Vaccine | Vaccine
A vaccine is an antigenic preparation used to establish immunity to a disease. The term derives from Edward Jenner's use of cowpox ("vacca" means cow in Latin), which, when administered to humans, provided them protection against smallpox, the work which Louis Pasteur and others carried on. Vaccines are based on the concept of variolation originating in China, in which a person is deliberately infected with a weak form of smallpox. Jenner realized that milkmaids who had contact with cowpox did not get smallpox. The process of distributing and administrating vaccines is referred to as vaccination. Since vaccination was much safer, smallpox inoculation fell into disuse and was eventually banned in England in 1840.
Vaccines can be prophylactic (e.g. to prevent or ameliorate the effects of a future infection by any natural or "wild" pathogen), or therapeutic (e.g. vaccines against cancer are also being investigated; see cancer vaccine).
# Types of vaccines
Vaccines may be dead or inactivated organisms or purified products derived from them.
There are four types of traditional vaccines:
- Vaccines containing killed microorganisms - these are previously virulent micro-organisms that have been killed with chemicals or heat. Examples are vaccines against flu, cholera, bubonic plague, and hepatitis A.
- Vaccines containing live, attenuated microorganisms - these are live micro-organisms that have been cultivated under conditions that disable their virulent properties. They typically provoke more durable immunological responses and are the preferred type for healthy adults. Examples include yellow fever, measles, rubella, and mumps.
- Toxoids - these are inactivated toxic compounds from micro-organisms in cases where these (rather than the micro-organism itself) cause illness. Examples of toxoid-based vaccines include tetanus and diphtheria.
- Subunit - rather than introducing an inactivated or attenuated micro-organism to an immune system, a fragment of it can create an immune response. Characteristic examples include the subunit vaccine against HBV that is composed of only the surface proteins of the virus (produced in yeast) and the virus like particle (VLP) vaccine against Human Papillomavirus (HPV) that is composed of the viral major capsid protein.
The live tuberculosis vaccine is not the contagious strain, but a related strain called "BCG"; it is used in the United States very infrequently.
A number of innovative vaccines are also in development and in use:
- Conjugate - certain bacteria have polysaccharide outer coats that are poorly immunogenic. By linking these outer coats to proteins (e.g. toxins), the immune system can be led to recognize the polysaccharide as if it were a protein antigen. This approach is used in the Haemophilus influenzae type B vaccine.
- Recombinant Vector - by combining the physiology of one micro-organism and the DNA of the other, immunity can be created against diseases that have complex infection processes
- DNA vaccination - in recent years a new type of vaccine, created from an infectious agent's DNA called DNA vaccination, has been developed. It works by insertion (and expression, triggering immune system recognition) into human or animal cells, of viral or bacterial DNA. Some cells of the immune system that recognize the proteins expressed will mount an attack against these proteins and cells expressing them. Because these cells live for a very long time, if the pathogen that normally expresses these proteins is encountered at a later time, they will be attacked instantly by the immune system. One advantage of DNA vaccines is that they are very easy to produce and store. As of 2006, DNA vaccination is still experimental, but shows some promising results.
Note that while most vaccines are created using inactivated or attenuated compounds from micro-organisms, synthetic vaccines are composed mainly or wholly of synthetic peptides, carbohydrates or antigens. Some viral vaccines have been developed by use of cell lines derived from aborted fetuses ( )
# Developing immunity
The immune system recognizes vaccine agents as foreign, destroys them, and 'remembers' them. When the virulent version of an agent comes along, the immune system is thus prepared to respond, by (1) neutralizing the target agent before it can enter cells, and (2) by recognizing and destroying infected cells before that agent can multiply to vast numbers.
Vaccines have contributed to the eradication of smallpox, one of the most contagious and deadly diseases known to man. Other diseases such as rubella, polio, measles, mumps, chickenpox, and typhoid are nowhere near as common as they were just a hundred years ago. As long as the vast majority of people are vaccinated, it is much more difficult for an outbreak of disease to occur, let alone spread. This effect is called herd immunity. Polio, which is transmitted only between humans, is targeted by an extensive eradication campaign that has seen endemic polio restricted to only parts of four countries. The difficulty of reaching all children, however, has caused the eradication date to be missed twice by 2006.
# Vaccination schedule
In order to provide best protection, children are recommended to receive vaccinations as soon as their immune systems are sufficiently developed to respond to particular vaccines, with additional 'booster' shots often required to achieve 'full immunity'. This has led to the development of complex vaccination schedules. In the United States, the Advisory Committee on Immunization Practices, which recommends schedule additions for the Center for Disease Control, recommends routine vaccination of children against: hepatitis A, hepatitis B, polio, mumps, measles, rubella, diphtheria, pertussis, tetanus, HiB, chicken pox, rotavirus, influenza, meningococcal disease and pneumonia. The large number of vaccines and boosters recommended (up to 24 injections by age two) has led to problems with achieving full compliance. In order to combat declining compliance rates, various notification systems have been instituted and a number of combination injections are now marketed (e.g., Prevnar and ProQuad vaccines), which provide protection against multiple diseases.
Besides recommendations for infant vaccination boosters, many specific vaccines are recommended for repeated injections throughout life -- most commonly for measles, tetanus, influenza, and pneumonia. Pregnant women are often screened for continued resistance to rubella. In 2006, a vaccine was introduced against shingles, a disease caused by the chicken pox virus, which usually affects the elderly. Vaccine recommendations for the elderly concentrate on pneumonia and influenza, which are more deadly to that group.
# Vaccine controversies
Opposition to vaccination, from a wide array of vaccine critics, has existed since the earliest vaccination campaigns: .
A number of vaccines, including those given to very young children, have contained thiomersal, a preservative that metabolizes into ethylmercury. It has been used in some influenza, DTP (diphtheria, tetanus and pertussis) vaccine formulations. Since 1997, use of thimerosal has been gradually diminishing in western industrialized countries after recommendations by medical authorities, but trace amounts of thimerosal remain in many vaccines and in some vaccines, thimerosal has not yet been phased out despite recommendations. Some states in USA have enacted laws banning the use of thimerosal in childhood vaccines.
In the late 1990s, controversy over vaccines escalated in both the US and the United Kingdom when a study, published in the respected journal Lancet, by Dr. Andrew Wakefield suggested a possible link between bowel disorders, autism and the MMR vaccine, and urged further research. His report garnered significant media attention, leading to a drop in the uptake of the MMR vaccine in the United Kingdom and some other countries. In response to the controversies, a number of studies with larger sample sizes were conducted, and failed to confirm the findings. . In 2004, 10 of the 13 authors of the original Wakefield study retracted the paper's "interpretation", or conclusion, section, which had claimed:
"Interpretation. We identified associated gastrointestinal disease and developmental regression in a group of previously normal children, which was generally associated in time with possible environmental triggers."
The retraction of this claim stated that the data were insufficient to establish a causal link between MMR vaccine and autism. Wakefield was later found to have received £435,000 in fees from trial lawyers attempting to show the vaccine was dangerous . Also in 2004, the United States' Institute of Medicine reported that evidence "favors rejection" of any link between vaccines containing thimerosal, or MMR, and the development of autism .
In 2004 and 2005, England and Wales experienced an increase in the incidence of mumps infections among adolescents and young adults. The age group affected were too old to have received the routine MMR immunisations around the time the paper by Wakefield et al was published, and too young to have contracted natural mumps as a child, and thus to achieve a herd immunity effect. With the decline in mumps that followed the introduction of the MMR vaccine, these individuals had not been exposed to the disease, but still had no immunity, either natural or vaccine induced. Therefore, as immunization rates declined following the controversy and the disease re-emerged, they were susceptible to infection. . This and similar examples indicate the importance of:
- careful modelling to anticipate the impact that an immunisation campaign will have on the epidemiology of the disease in the medium to long term
- ongoing surveillance for the relevant disease following introduction of a new vaccine and
- maintaining high immunisation rates, even when a disease has become rare.
There is opposition to any type of vaccination from some sectors of the community, particularly those who favor 'alternative' health care. Some skeptics claim that mass immunization is a eugenics program. Naturopaths and other alternative health care practitioners sometimes offer their own, alternative treatments to conventional vaccination.
In Australia, a massive increase in vaccination rates was observed when the federal government made certain benefits (such as the universal 'Family Allowance' welfare payments for parents of children) dependent on vaccination. As well, children were not allowed into school unless they were either vaccinated or their parents completed a statutory declaration refusing to immunize them, after discussion with a doctor, and other bureaucracy. (Similar school-entry vaccination regulations have been in place in some parts of Canada for several years.) It became easier and cheaper to vaccinate one's children than not to. When faced with the annoyance, many more casual objectors simply gave in.
Another vaccination controversy concerns smallpox. Since it has been eradicated, some suggest that the stores of smallpox virus should be destroyed. In an article on Newswise both sides debate the issue: "The destruction of remaining smallpox virus stocks is an overdue step forward for public health and security that will dramatically reduce the possibility that this scourge will kill again, either by accident or design, argues Edward Hammond of The Sunshine Project, an organisation seeking international consensus against biological weapons."
"But John Agwunobi of the US Department of Health and Human Services believes that clandestine stocks almost certainly exist and that destroying the virus would be “irreversible and short sighted.”
# Efficacy of vaccines
Vaccines do not guarantee complete protection from a disease. Sometimes this is because the host's immune system simply doesn't respond adequately or at all. This may be due to a lowered immunity in general (diabetes, steroid use, HIV infection) or because the host's immune system does not have a B-cell capable of generating antibodies to that antigen.
Even if the host develops antibodies, the human immune system is not perfect and in any case the immune system might still not be able to defeat the infection.
Adjuvants are typically used to boost immune response. Adjuvants are sometimes called the dirty little secret of vaccines in the scientific community, as not much is known about how adjuvants work. Most often aluminium adjuvants are used, but adjuvants like squalene are also used in some vaccines and more vaccines with squalene and phosphate adjuvants are being tested.
The efficacy or performance of the vaccine is dependent on a number of factors:
- the disease itself (for some diseases vaccination performs better than for other diseases)
- the strain of vaccine (some vaccinations are for different strains of the disease)
- whether one kept to the timetable for the vaccinations (see Vaccination schedule)
- some individuals are 'non-responders' to certain vaccines, meaning that they do not generate antibodies even after being vaccinated correctly
- other factors such as ethnicity or genetic predisposition
When a vaccinated individual does develop the disease vaccinated against, the disease is likely to be milder than without vaccination.
# Economics of vaccine development
One challenge in vaccine development is economic: many of the diseases most demanding a vaccine, including HIV, malaria and tuberculosis, exist principally in poor countries. Although some contend pharmaceutical firms and biotech companies have little incentive to develop vaccines for these diseases, because there is little revenue potential, the number of vaccines actually administered has risen dramatically in recent decades. This increase, particularly in the number of different vaccines administered to children before entry into schools may be due to government mandates, rather than economic incentive. Most vaccine development to date has relied on 'push' funding by government and non-profit organizations, of government agencies, universities and non-profit organizations.
Many researchers and policymakers are calling for a different approach, using 'pull' mechanisms to motivate industry. Mechanisms such as
prizes, tax credits, or advance market commitments could ensure a financial return to firms that successfully developed a HIV vaccine. If the policy were well-designed, it might also ensure people have access to a vaccine if and when it is developed.
Statistics from the government agencies of the U.S., the British Commonwealth and the U.K. show that between the 1800s and the time various vaccines were introduced, the incidences of the diseases for which vaccines were provided were reduced by 70%-90%. For some, this prompts the question as to whether the reduction in the morbidity and mortality due to these diseases is owed to improved sewage systems, food refrigeration, improved home and work environments, and the introduction of antibiotics, all of which occurred during the same period.
# Preservatives
In order to extend shelf life and reduce production and storage costs, thimerosal, a preservative containing about 49% of a form of mercury called ethylmercury, was used routinely until recent years. Thimerosal has been phased out in the U.S. in all but a few flu vaccines (it has been phased out earlier in other countries, e.g. Denmark in 1992), but may be used in stages of manufacture. Parents wishing to avoid this preservative, most common in multi-dose containers of influenza vaccine, may specifically ask for thimerosal-free alternatives that contain only trace amounts.
A study published in the September 2007 New England Journal of Medicine reported no causal association between early exposure to mercury from thimerosal-containing vaccines and neurological problems by the age of 7 to 10 years old.
# Vaccines for nonhumans | Vaccine
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]
A vaccine is an antigenic preparation used to establish immunity to a disease. The term derives from Edward Jenner's use of cowpox ("vacca" means cow in Latin), which, when administered to humans, provided them protection against smallpox, the work which Louis Pasteur and others carried on. Vaccines are based on the concept of variolation originating in China, in which a person is deliberately infected with a weak form of smallpox. Jenner realized that milkmaids who had contact with cowpox did not get smallpox. The process of distributing and administrating vaccines is referred to as vaccination. Since vaccination was much safer, smallpox inoculation fell into disuse and was eventually banned in England in 1840.
Vaccines can be prophylactic (e.g. to prevent or ameliorate the effects of a future infection by any natural or "wild" pathogen), or therapeutic (e.g. vaccines against cancer are also being investigated; see cancer vaccine).
# Types of vaccines
Vaccines may be dead or inactivated organisms or purified products derived from them.
There are four types of traditional vaccines[2]:
- Vaccines containing killed microorganisms - these are previously virulent micro-organisms that have been killed with chemicals or heat. Examples are vaccines against flu, cholera, bubonic plague, and hepatitis A.
- Vaccines containing live, attenuated microorganisms - these are live micro-organisms that have been cultivated under conditions that disable their virulent properties. They typically provoke more durable immunological responses and are the preferred type for healthy adults. Examples include yellow fever, measles, rubella, and mumps.
- Toxoids - these are inactivated toxic compounds from micro-organisms in cases where these (rather than the micro-organism itself) cause illness. Examples of toxoid-based vaccines include tetanus and diphtheria.
- Subunit - rather than introducing an inactivated or attenuated micro-organism to an immune system, a fragment of it can create an immune response. Characteristic examples include the subunit vaccine against HBV that is composed of only the surface proteins of the virus (produced in yeast) and the virus like particle (VLP) vaccine against Human Papillomavirus (HPV) that is composed of the viral major capsid protein.
The live tuberculosis vaccine is not the contagious strain, but a related strain called "BCG"; it is used in the United States very infrequently.
A number of innovative vaccines are also in development and in use:
- Conjugate - certain bacteria have polysaccharide outer coats that are poorly immunogenic. By linking these outer coats to proteins (e.g. toxins), the immune system can be led to recognize the polysaccharide as if it were a protein antigen. This approach is used in the Haemophilus influenzae type B vaccine.
- Recombinant Vector - by combining the physiology of one micro-organism and the DNA of the other, immunity can be created against diseases that have complex infection processes
- DNA vaccination - in recent years a new type of vaccine, created from an infectious agent's DNA called DNA vaccination, has been developed. It works by insertion (and expression, triggering immune system recognition) into human or animal cells, of viral or bacterial DNA. Some cells of the immune system that recognize the proteins expressed will mount an attack against these proteins and cells expressing them. Because these cells live for a very long time, if the pathogen that normally expresses these proteins is encountered at a later time, they will be attacked instantly by the immune system. One advantage of DNA vaccines is that they are very easy to produce and store. As of 2006, DNA vaccination is still experimental, but shows some promising results.
Note that while most vaccines are created using inactivated or attenuated compounds from micro-organisms, synthetic vaccines are composed mainly or wholly of synthetic peptides, carbohydrates or antigens. Some viral vaccines have been developed by use of cell lines derived from aborted fetuses ( http://www.lifecanada.org/html/science/Vaccines/ABriefHistoryofHumanDiploidCellStrains.pdf )
# Developing immunity
The immune system recognizes vaccine agents as foreign, destroys them, and 'remembers' them. When the virulent version of an agent comes along, the immune system is thus prepared to respond, by (1) neutralizing the target agent before it can enter cells, and (2) by recognizing and destroying infected cells before that agent can multiply to vast numbers.
Vaccines have contributed to the eradication of smallpox, one of the most contagious and deadly diseases known to man. Other diseases such as rubella, polio, measles, mumps, chickenpox, and typhoid are nowhere near as common as they were just a hundred years ago. As long as the vast majority of people are vaccinated, it is much more difficult for an outbreak of disease to occur, let alone spread. This effect is called herd immunity. Polio, which is transmitted only between humans, is targeted by an extensive eradication campaign that has seen endemic polio restricted to only parts of four countries.[3] The difficulty of reaching all children, however, has caused the eradication date to be missed twice by 2006.
# Vaccination schedule
In order to provide best protection, children are recommended to receive vaccinations as soon as their immune systems are sufficiently developed to respond to particular vaccines, with additional 'booster' shots often required to achieve 'full immunity'. This has led to the development of complex vaccination schedules. In the United States, the Advisory Committee on Immunization Practices, which recommends schedule additions for the Center for Disease Control, recommends routine vaccination of children against: hepatitis A, hepatitis B, polio, mumps, measles, rubella, diphtheria, pertussis, tetanus, HiB, chicken pox, rotavirus, influenza, meningococcal disease and pneumonia. The large number of vaccines and boosters recommended (up to 24 injections by age two) has led to problems with achieving full compliance. In order to combat declining compliance rates, various notification systems have been instituted and a number of combination injections are now marketed (e.g., Prevnar and ProQuad vaccines), which provide protection against multiple diseases.
Besides recommendations for infant vaccination boosters, many specific vaccines are recommended for repeated injections throughout life -- most commonly for measles, tetanus, influenza, and pneumonia. Pregnant women are often screened for continued resistance to rubella. In 2006, a vaccine was introduced against shingles, a disease caused by the chicken pox virus, which usually affects the elderly. Vaccine recommendations for the elderly concentrate on pneumonia and influenza, which are more deadly to that group.
# Vaccine controversies
Opposition to vaccination, from a wide array of vaccine critics, has existed since the earliest vaccination campaigns: [4].
A number of vaccines, including those given to very young children, have contained thiomersal, a preservative that metabolizes into ethylmercury. It has been used in some influenza, DTP (diphtheria, tetanus and pertussis) vaccine formulations. Since 1997, use of thimerosal has been gradually diminishing in western industrialized countries after recommendations by medical authorities, but trace amounts of thimerosal remain in many vaccines and in some vaccines, thimerosal has not yet been phased out despite recommendations. Some states in USA have enacted laws banning the use of thimerosal in childhood vaccines.
In the late 1990s, controversy over vaccines escalated in both the US and the United Kingdom when a study, published in the respected journal Lancet, by Dr. Andrew Wakefield suggested a possible link between bowel disorders, autism and the MMR vaccine, and urged further research.[1] His report garnered significant media attention, leading to a drop in the uptake of the MMR vaccine in the United Kingdom and some other countries. In response to the controversies, a number of studies with larger sample sizes were conducted, and failed to confirm the findings.[5] [6]. In 2004, 10 of the 13 authors of the original Wakefield study retracted the paper's "interpretation", or conclusion, section, which had claimed:
"Interpretation. We identified associated gastrointestinal disease and developmental regression in a group of previously normal children, which was generally associated in time with possible environmental triggers."
The retraction of this claim stated that the data were insufficient to establish a causal link between MMR vaccine and autism.[7] Wakefield was later found to have received £435,000 in fees from trial lawyers attempting to show the vaccine was dangerous [8] [9]. Also in 2004, the United States' Institute of Medicine reported that evidence "favors rejection" of any link between vaccines containing thimerosal, or MMR, and the development of autism [10].
In 2004 and 2005, England and Wales experienced an increase in the incidence of mumps infections among adolescents and young adults. The age group affected were too old to have received the routine MMR immunisations around the time the paper by Wakefield et al was published, and too young to have contracted natural mumps as a child, and thus to achieve a herd immunity effect. With the decline in mumps that followed the introduction of the MMR vaccine, these individuals had not been exposed to the disease, but still had no immunity, either natural or vaccine induced. Therefore, as immunization rates declined following the controversy and the disease re-emerged, they were susceptible to infection. [11] [12]. This and similar examples indicate the importance of:
- careful modelling to anticipate the impact that an immunisation campaign will have on the epidemiology of the disease in the medium to long term
- ongoing surveillance for the relevant disease following introduction of a new vaccine and
- maintaining high immunisation rates, even when a disease has become rare.
There is opposition to any type of vaccination from some sectors of the community, particularly those who favor 'alternative' health care. Some skeptics claim that mass immunization is a eugenics program. Naturopaths and other alternative health care practitioners sometimes offer their own, alternative treatments to conventional vaccination.
In Australia, a massive increase in vaccination rates was observed when the federal government made certain benefits (such as the universal 'Family Allowance' welfare payments for parents of children) dependent on vaccination. As well, children were not allowed into school unless they were either vaccinated or their parents completed a statutory declaration refusing to immunize them, after discussion with a doctor, and other bureaucracy. (Similar school-entry vaccination regulations have been in place in some parts of Canada for several years.) It became easier and cheaper to vaccinate one's children than not to. When faced with the annoyance, many more casual objectors simply gave in.
Another vaccination controversy concerns smallpox. Since it has been eradicated, some suggest that the stores of smallpox virus should be destroyed. In an article on Newswise [13] both sides debate the issue: "The destruction of remaining smallpox virus stocks is an overdue step forward for public health and security that will dramatically reduce the possibility that this scourge will kill again, either by accident or design, argues Edward Hammond of The Sunshine Project, an organisation seeking international consensus against biological weapons."
"But John Agwunobi of the US Department of Health and Human Services believes that clandestine stocks almost certainly exist and that destroying the virus would be “irreversible and short sighted.” [14]
# Efficacy of vaccines
Vaccines do not guarantee complete protection from a disease. Sometimes this is because the host's immune system simply doesn't respond adequately or at all. This may be due to a lowered immunity in general (diabetes, steroid use, HIV infection) or because the host's immune system does not have a B-cell capable of generating antibodies to that antigen.
Even if the host develops antibodies, the human immune system is not perfect and in any case the immune system might still not be able to defeat the infection.
Adjuvants are typically used to boost immune response. Adjuvants are sometimes called the dirty little secret of vaccines [15] in the scientific community, as not much is known about how adjuvants work. Most often aluminium adjuvants are used, but adjuvants like squalene are also used in some vaccines and more vaccines with squalene and phosphate adjuvants are being tested.
The efficacy or performance of the vaccine is dependent on a number of factors:
- the disease itself (for some diseases vaccination performs better than for other diseases)
- the strain of vaccine (some vaccinations are for different strains of the disease) [16]
- whether one kept to the timetable for the vaccinations (see Vaccination schedule)
- some individuals are 'non-responders' to certain vaccines, meaning that they do not generate antibodies even after being vaccinated correctly
- other factors such as ethnicity or genetic predisposition
When a vaccinated individual does develop the disease vaccinated against, the disease is likely to be milder than without vaccination.
# Economics of vaccine development
One challenge in vaccine development is economic: many of the diseases most demanding a vaccine, including HIV, malaria and tuberculosis, exist principally in poor countries. Although some contend pharmaceutical firms and biotech companies have little incentive to develop vaccines for these diseases, because there is little revenue potential, the number of vaccines actually administered has risen dramatically in recent decades. This increase, particularly in the number of different vaccines administered to children before entry into schools may be due to government mandates, rather than economic incentive. Most vaccine development to date has relied on 'push' funding by government and non-profit organizations, of government agencies, universities and non-profit organizations.
Many researchers and policymakers are calling for a different approach, using 'pull' mechanisms to motivate industry. Mechanisms such as
prizes, tax credits, or advance market commitments could ensure a financial return to firms that successfully developed a HIV vaccine. If the policy were well-designed, it might also ensure people have access to a vaccine if and when it is developed.
Statistics from the government agencies of the U.S., the British Commonwealth and the U.K. show that between the 1800s and the time various vaccines were introduced, the incidences of the diseases for which vaccines were provided were reduced by 70%-90%. For some, this prompts the question as to whether the reduction in the morbidity and mortality due to these diseases is owed to improved sewage systems, food refrigeration, improved home and work environments, and the introduction of antibiotics, all of which occurred during the same period.
# Preservatives
In order to extend shelf life and reduce production and storage costs, thimerosal, a preservative containing about 49% of a form of mercury called ethylmercury, was used routinely until recent years.[17] Thimerosal has been phased out in the U.S. in all but a few flu vaccines [18] (it has been phased out earlier in other countries, e.g. Denmark in 1992), but may be used in stages of manufacture. Parents wishing to avoid this preservative, most common in multi-dose containers of influenza vaccine, may specifically ask for thimerosal-free alternatives that contain only trace amounts.[19]
A study published in the September 2007 New England Journal of Medicine reported no causal association between early exposure to mercury from thimerosal-containing vaccines and neurological problems by the age of 7 to 10 years old.[2]
# Vaccines for nonhumans
Template:Seealso | https://www.wikidoc.org/index.php/Vaccine | |
519f392a4349628795afab106a89b0ec3edf63c3 | wikidoc | Vanilla | Vanilla
Vanilla is a flavouring derived from orchids in the genus Vanilla native to Mexico. The name came from the Spanish word "vainilla," meaning "little pod."
Vanilla is valued for its sweet flavour and scent and is widely used in the preparation of desserts and perfumes. Today, the majority of the world's vanilla is produced in a small region of Madagascar, an island in the Indian Ocean.
# Vanilla orchid
The main species harvested for vanillin is Vanilla planifolia. Although it is native to Mexico, it is now widely grown throughout the tropics. Madagascar is the world's largest producer. Additional sources include Vanilla pompona and Vanilla tahitiensis (grown in Tahiti and Niue), although the vanillin content of these species is much less than Vanilla planifolia.
Vanilla grows as a vine, climbing up an existing tree, pole, or other support. It can be grown in a wood (on trees), in a plantation (on trees or poles), or in a "shader", in increasing orders of productivity. Left alone, it will grow as high as possible on the support, with few flowers. Every year, growers fold the higher parts of the plant downwards so that the plant stays at heights accessible by a standing human. This also greatly stimulates flowering.
The distinctively flavoured compounds are found in the fruit, which results from the pollination of the flower. One flower produces one fruit. Vanilla planifolia flowers are hermaphroditic: they carry both male (anther) and female (stigma) organs; however, to avoid self-pollination, a membrane separates those organs. As Charles François Antoine Morren, a Belgian botanist found, the flowers can only be naturally pollinated by a specific Melipone bee found in Mexico. Growers have tried to bring this bee into other growing locales, to no avail. The only way to produce fruits is thus artificial pollination.
A simple and efficient artificial pollination method was introduced in 1841 by a 12-year-old slave named Edmond Albius on Réunion: a method still used today. Using a beveled sliver of bamboo, an agricultural worker folds back the membrane separating the anther and the stigma, then presses the anther on the stigma. The flower is then self-pollinated, and will produce a fruit. The vanilla flower lasts about one day, sometimes less, thus growers have to inspect their plantations every day for open flowers, a labour-intensive task.
The fruit (a seed capsule), if left on the plant, will ripen and open at the end; it will then release the distinctive vanilla smell. The fruit contains tiny, flavourless seeds. In dishes prepared with whole natural vanilla, these seeds are recognizable as black specks.
Like other orchids' seeds, vanilla seed will not germinate without the presence of certain mycorrhizal fungi. Instead, growers reproduce the plant by cutting: they remove sections of the vine with six or more leaf nodes, a root opposite each leaf. The two lower leaves are removed, and this area is buried in loose soil at the base of a support. The remaining upper roots will cling to the support, and often grow down into the soil. Growth is rapid under good conditions.
# History
The first to cultivate vanilla were the Totonac people, who inhabit the Mazantla Valley on the Gulf Coast of Mexico in the present-day state of Veracruz. According to Totonac mythology, the tropical orchid was born when Princess Xanat, forbidden by her father from marrying a mortal, fled to the forest with her lover. The lovers were captured and beheaded. Where their blood touched the ground, the vine of the tropical orchid grew.
In the fifteenth century, Aztecs from the central highlands of Mexico conquered the Totonacs, and the conquerors soon developed a taste for the vanilla bean. They named the bean tlilxochitl, or "black flower", after the mature bean, which shrivels and turns black shortly after it is picked. After they were subjected to the Aztecs the Totonacs paid their tribute by sending vanilla beans to the Aztec capital, Tenochtitlan.
Vanilla was completely unknown in the Old World before Columbus. Spanish explorers who arrived on the Gulf Coast of Mexico in the early sixteenth century gave vanilla its name. The Spanish and Portuguese sailors and explorers brought vanilla into Africa and Asia in the 16th century. They called it vainilla, or "little pod", The word vanilla entered the English language in the 1754, when the botanist Philip Miller wrote about the genus in his Gardener’s Dictionary.
Until the mid-19th century, Mexico was the chief producer of vanilla. In 1819, however, French entrepreneurs shipped vanilla beans to the Réunion and Mauritius islands with the hope of producing vanilla there. After Edmond Albius, a 12-year-old slave from Réunion Island, discovered how to pollinate the flowers quickly by hand, the pods began to thrive. Soon the tropical orchids were sent from Réunion Island to the Comoros Islands and Madagascar along with instructions for pollinating them. By 1898, Madagascar, Réunion, and the Comoros Islands produced 200 metric tons of vanilla beans, about 80 percent of world production.
The market price of vanilla rose dramatically in the late 1970s, due to a typhoon. Prices stayed stable at this level through the early 1980s despite the pressure of recently introduced Indonesian vanilla. In the mid-1980s, the cartel that had controlled vanilla prices and distribution since its creation in 1930 disbanded. Prices dropped 70 percent over the next few years, to nearly US$20 per kilo. This changed, due to typhoon Huddah, which struck early in the year 2000. The typhoon, political instability, and poor weather in the third year drove vanilla prices to an astonishing US$500 per kilo in 2004, bringing new countries into the vanilla industry. A good crop, coupled with decreased demand caused by the production of imitation vanilla, have pushed the market price down to the $40 per kilo range in the middle of 2005.
Madagascar (mostly the fertile region of Sava) accounts for half of the global production of vanilla. Mexico, once the leading producer of natural vanilla with an annual 500 tons, produced only 10 tons of vanilla in 2006. An estimated 95% of “vanilla” products actually contain artificial vanillin, produced from lignin.
# Chemistry
Though there are many compounds present in the extracts of vanilla, the compound vanillin (4-hydroxy-3-methoxybenzaldehyde) is primarily responsible for the characteristic flavour and smell of vanilla. Another minor component of vanilla essential oil is piperonal (heliotropin). Piperonal and other substances affect the odour of natural vanilla. Vanillin was first isolated from vanilla pods by Gobley in 1858. By 1874, it had been obtained from glycosides of pine tree sap, temporarily causing a depression in the natural vanilla industry.
Vanilla essence comes in two forms. Real seedpod extract is an extremely complicated mixture of several hundred different compounds. Synthetic essence, consisting basically of a solution of synthetic vanillin in ethanol, is derived from phenol and is of high purity.
# General production guidelines
It is well know that good vanilla will only come from good vines. In order to achieve such high quality a lot of labour has to be put on. Commercial Vanilla production can be performed under open field and “Greenhouse” operations. Both production systems share the following similarities:
- Plant height and number of years before producing the first grains
- Shade necessities
- Amount of organic matter needed
- A tree or frame to grow around it (Bamboo, coconut or Erythrina lanceolata)
- Labour intensity (pollination and harvest activities)
Vanilla grows best under hot humid climate from sea level to an elevation of 1500m. Most of its production is done 10 to 20 degrees above and below the equator. The ideal growing conditions are moderate rainfall 150-300cm evenly distributed through 10 months of the year. The optimum temperatures for cultivation are 60 to 90 F during the day and 60 to 70 F during the night. Ideal humidity is around 80% and under normal greenhouse condition it can be achieved by an evaporated cooler. However, since greenhouse Vanilla is grown near the equator and under polymer (HDPE) netting (Shading of 50%) this humidity is achieved by the RH of environment.
Soils for vanilla cultivation should be loose with high organic matter content and loamy texture. They must be well drained and a slight slope helps in this condition. Soil pH has not been well documented but some researchers have indicated an optimum soil pH of around 5.3 . Mulch is very important for proper growth of the vine and a considerable portion of mulch should be placed in the base of the vine. Fertilization varies with soil conditions but general recommendations are: 40 to 60g of N, 20 to 30g of P2O5 and 60 to 100g of K2O should be applied to each plant per year besides organic manures like vermicompost, oil cakes, poultry manure and wood ash. Foliar applications are also good for vanilla and a solution of 1% NPK (17:17:17) can be spray in the plant once a month. Vanilla likes a lot of organic matter; therefore 3 to 4 applications of mulch a year are adequate for the plant.
Propagation, Pre-plant preparation and Type of stock
Dissemination of vanilla can be achieved either by stem cutting or by tissue culture. For stem cutting a progeny garden needs to be established. Recommendations for establishing this garden vary, but in general trenches of 60cm in width and 45 cm in depth and 60 cm spacing for each plant is necessary. All plants need to grow under 50% shade as well as the rest of the crop. Mulching the trenches with coconut husk and micro irrigation provide ideal micro climate for vegetative growth. Cuttings between 60 and 120cm should be selected for planting in the field or greenhouse. Cuttings below 60 cm need to be rooted and raised in a separate nursery before planting. Planting material should always come from unflowered portions of the vine. Wilting of the cuttings before planting provides better conditions for root initiation and establishment.
Before planting the cuttings, trees that will support the vine must be planted at least three months before sowing the cuttings. Pits of 30 x 30 x 30 cm are dug 30 cm away from the three and field with FYM (farm yard manure) (or Vermicompost), sand and top soil mixed well. An average of 2000 cuttings can be planted per hectare. One important consideration is that when planting the cuttings from the base 4 leaves should be pruned and the pruned basal point must be pressed into the soil in a way that the 4 nodes are in close contact with the soil and are placed at a depth of 15 to 20cm. The top portion of the cutting is tied up to the tree using natural fibers like banana or hemp.
Tissue culture
Several methods have been proposed for vanilla tissue culture, but all of them begin from axillary buds of the vanilla vine. In vitro multiplication has also been achieved through culture of callus masses, protocorns, root tips and stem nodes. Description of any of these processes can be obtained from the references listed before, but all of them are successful in generation of new vanilla plants that first need to be grown up to a height of at least 30 cm before they can be planted in the field or greenhouse.
Scheduling considerations
In the tropics the ideal time for planting Vanilla is from September to November when the weather is neither to rainy or to dry; but this recommendation vary with growing conditions. Cuttings take 1 to 8 weeks to establish roots and show initial signs of growth from one of the leaf axils. A thick mulch of leaves should be provided immediately after planting as additional source of organic matter. From cuttings to produce flower and therefore pods it takes around three years. As with most orchids, the blossoms grow along stems branching from the main vine. The buds, growing along the 6 to 10 inch stems, bloom and mature in sequence, each at a different interval.
Pollination
Flowering normally occurs every spring and without pollination the blossom wilts and falls, and no vanilla bean can grow. Each flower must be hand-pollinated within 12 hours of opening. The only insect capable of pollinating the blossom is the Melipona, a bee, native only to Mexico. All vanilla grown today is pollinated by hand. A small splinter of wood or a grass stem is used to lift the rostellum or moved the flap upward so that the overhanging anther can be pressed against the stigma and self pollinate the vine. Generally one flower per raceme opens per day and therefore the raceme may be in flowering for over 20 days. A healthy vine should produce about 50 to 100 beans per year; however growers are careful to pollinate only 5 to 6 flowers from the 20 on each raceme. The first 5 to 6 flowers that open per vine should be pollinated so that the beans are similar in age. These agronomic practices facilitate harvest and increases bean quality. It takes the fruits to develop 5 to 6 weeks but it takes around 9 months for the bean to mature. Over pollination will result in diseased and inferior bean quality. A vine remains productive between 12 to 14 years.
Pest and disease management
Most of the diseases come from the uncharacteristic growing conditions of vanilla. Therefore conditions like excess water, insufficient drainage, heavy mulch, over pollination and too much shade favor disease development. Vanilla is susceptible to many fungal and viral diseases. Fusarium sp,Sclerotium sp, Phytopthora sp and Collectrotricum sp cause rots of root, stem, leaf, bean and shoot apex. These diseases can be controlled by spraying Bordeaux mixture (1%), Bavistin (0.2%) and Copper oxy chloride (0.2%).
Biological control of the spread of such diseases can be managed by applying to the soil Trichoderma (0.5 kg per plant in the rhizosphere) and foliar application of Pseudomonads (0.2%). Mosaic, leaf curl and Cymbidium mosaic potex virus are the common viral diseases. These diseases are transmitted through the sap; consequently affected plants have to be destroyed. The insect pests of vanilla include beetles and weevils which attack the flower, caterpillars, snakes and slugs that damage the tender parts of shoot, flower buds and immature beans and grass hoppers that affect cutting shoot tips. If organic agriculture is practiced, insecticides are avoided and mechanical measures are adopted for pest management. . Most of these practices are implemented under greenhouse cultivation since in the field such conditions are very difficult to achieve.
# Stages of production
- Harvest
The vanilla bean grows quickly on the vine but is not ready for harvest until maturity- approximately nine months. Harvesting vanilla beans is as labour intensive as pollinating the blossoms. Immature dark green pods are not harvested. Pale yellow discoloration which commences at the distal end of the beans is an indication of the maturity of pods. Each bean ripens at its own time, requiring a daily harvest. To ensure the finest flavor from every bean, each individual pod must be picked by hand just as it beginning to split on the end. Over mature beans are likely to split causing a reduction in market value. Its commercial value is fixed based on the length of the pod. If the bean is more than 15 cm in length it belongs to first quality product. If the beans are between 10 to 15 cm long pods are under second quality and beans less than 10 cm in length are under third quality. Each of the beans has a considerable amount of seeds inside the pod which are covered by a dark red liquid from which the vanilla essence is extracted. Vanilla bean yield depends on the care and management given to the hanging and fruiting vines. Any practice directed to stimulate aerial root production has a direct effect on vine productivity. A five year old vine can produce between 1.5 and 3kg pods and this production can increase up to 6kg after a few years. The harvested green beans can be commercialized as such or cured in order to get a better market price
- Curing
Several methods exist in the market for curing vanilla; nevertheless all of them consist of four basic steps: a- killing, b- sweating, c-slow drying and d- conditioning of the beans.
- Killing
The vegetative tissue of the vanilla pod is killed to prevent further growing. The method of killing varies, but may be accomplished by sun killing, oven killing, hot water killing, killing by scratching, or killing by freezing. Hot water killing consist in dipping the pods in hot water (63-65C) for three minutes to stop the vegetative growth of the pods and initiate enzymatic reactions responsible for the aroma.
- Sweating
This method consists of wrapping the beans in woolen cloth in order to raise the temperature (45-65C, under high humidity) of the beans under sunlight conditions for one hour for up to 10 days. During this time the pods are stored in wooden boxes under air tight conditions during the night. Under these conditions the beans develop the characteristic vanilla flavor, aroma and color. Its purpose is to allow enzymes to catalyze the reactions involved in generating the vanilla flavor and aroma.
- Drying
To prevent rotting and to lock the aroma in the pods, the pods are dried. Often, pods are laid out in the sun during the mornings and returned to their boxes in the afternoons. When 25-30% of the pods' weight is moisture (as opposed to the 60-70% they began drying with) they have completed the curing process and will exhibit their fullest aromatic qualities. This reduction in moisture content is achieved by spreading the beans on a wooden rack in a room for three to four weeks.
- Conditioning of the bean
This step is performed by storing the pods for a few moths in closed boxes where the fragrance develops. The processed beans are sorted, graded, bundled and wrapped in paraffin paper and preserved for the development of desired bean qualities, especially flavour and aroma. The cured vanilla beans contain an average of 2.5 % vanillin.
Grading
Once fully cured, the vanilla is sorted by quality and graded.
# Culinary uses
There are three main commercial preparations of natural vanilla:
- whole pod
- powder (ground pods, kept pure or blended with sugar, starch or other ingredients)
- extract (in alcoholic solution)
Vanilla flavouring in food may be achieved by adding vanilla extract or by cooking vanilla pods in the liquid preparation. A stronger aroma may be attained if the pods are split in two, exposing more of the pod's surface area to the liquid. In this case, the pods' seeds are mixed into the preparation. Natural vanilla gives a brown or yellow colour to preparations, depending on the concentration.
Good quality vanilla has a strong aromatic flavour, but food with small amounts of low quality vanilla or artificial vanilla-like flavourings are far more common, since true vanilla is much more expensive.
A major use of vanilla is in flavouring ice cream. The most common flavour of ice cream is vanilla, and thus most people consider it to be the "default" flavour. By analogy, the term "vanilla" is sometimes used as a synonym for "plain". Although vanilla is a prized flavoring agent on its own, it is also used to enhance the flavor of other substances, to which its own flavor is often complementary, such as chocolate, custard, caramel, coffee etc.
The cosmetics industry uses vanilla to make perfume.
The food industry uses methyl and ethyl vanillin. Ethyl vanillin is more expensive, but has a stronger note. Cook's Illustrated ran several taste tests pitting vanilla against vanillin in baked goods and other applications, and to the consternation of the magazine editors, tasters could not differentiate the flavour of vanillin from vanilla; however, for the case of vanilla ice cream, natural vanilla won out.
# Medicinal effects
In old medicinal literature, vanilla is described as an aphrodisiac and a remedy for fevers. These purported uses have never been scientifically proven, but it has been shown that vanilla does increase levels of catecholamines (including epinephrine, more commonly known as adrenaline), and as such can also be considered mildly addictive.
In an in-vitro test vanilla was able to block quorum sensing in bacteria. This is medically interesting because in many bacteria quorum sensing signals function as a switch for virulence. The microbes only become virulent when the signals indicate that they have the numbers to resist the host immune system response.
The essential oils of vanilla and vanillin are sometimes used in aromatherapy.
# Specific types of vanilla
Bourbon vanilla or Bourbon-Madagascar vanilla, produced from Vanilla planifolia plants introduced from the Americas, is the term used for vanilla from Indian Ocean islands such as Madagascar, the Comoros, and Réunion, formerly the Île Bourbon.
Mexican vanilla, made from the native Vanilla planifolia, is produced in much less quantity and marketed as the vanilla from the land of its origin. Vanilla sold in tourist markets around Mexico is sometimes not actual vanilla extract, but is mixed with an extract of the tonka bean, which contains coumarin. Tonka bean extract smells and tastes like vanilla, but coumarin has been shown to cause liver damage in lab animals and is banned in the US by the Food and Drug Administration.
Tahitian vanilla is the name for vanilla from French Polynesia, made with Vanilla tahitiensis. This species is descended from V. plantifolia that was introduced to Tahiti before mutating into a distinct species.
The term French vanilla is not a type of vanilla, but is often used to designate preparations that have a strong vanilla aroma, and contain vanilla grains. The name originates from the French style of making ice cream custard base with vanilla pods, cream, and egg yolks. Alternatively, French vanilla is taken to refer to a vanilla-custard flavour. Syrup labelled as French vanilla may include custard, caramel or butterscotch flavours in addition to vanilla.
- A vanilla plantation in open field on Réunion.
A vanilla plantation in open field on Réunion.
- A vanilla plantation in a "shader" (ombrière) on Réunion.
A vanilla plantation in a "shader" (ombrière) on Réunion.
- Flower
Flower
- Green fruits
Green fruits | Vanilla
Vanilla is a flavouring derived from orchids in the genus Vanilla native to Mexico. The name came from the Spanish word "vainilla," meaning "little pod."[1]
Vanilla is valued for its sweet flavour and scent and is widely used in the preparation of desserts and perfumes. Today, the majority of the world's vanilla is produced in a small region of Madagascar, an island in the Indian Ocean.[2]
# Vanilla orchid
The main species harvested for vanillin is Vanilla planifolia. Although it is native to Mexico, it is now widely grown throughout the tropics. Madagascar is the world's largest producer. Additional sources include Vanilla pompona and Vanilla tahitiensis (grown in Tahiti and Niue), although the vanillin content of these species is much less than Vanilla planifolia[citation needed].
Vanilla grows as a vine, climbing up an existing tree, pole, or other support. It can be grown in a wood (on trees), in a plantation (on trees or poles), or in a "shader", in increasing orders of productivity. Left alone, it will grow as high as possible on the support, with few flowers. Every year, growers fold the higher parts of the plant downwards so that the plant stays at heights accessible by a standing human. This also greatly stimulates flowering.
The distinctively flavoured compounds are found in the fruit, which results from the pollination of the flower. One flower produces one fruit. Vanilla planifolia flowers are hermaphroditic: they carry both male (anther) and female (stigma) organs; however, to avoid self-pollination, a membrane separates those organs. As Charles François Antoine Morren, a Belgian botanist found, the flowers can only be naturally pollinated by a specific Melipone bee found in Mexico. Growers have tried to bring this bee into other growing locales, to no avail. The only way to produce fruits is thus artificial pollination.
A simple and efficient artificial pollination method was introduced in 1841 by a 12-year-old slave named Edmond Albius on Réunion: a method still used today. Using a beveled sliver of bamboo,[3] an agricultural worker folds back the membrane separating the anther and the stigma, then presses the anther on the stigma. The flower is then self-pollinated, and will produce a fruit. The vanilla flower lasts about one day, sometimes less, thus growers have to inspect their plantations every day for open flowers, a labour-intensive task.
The fruit (a seed capsule), if left on the plant, will ripen and open at the end; it will then release the distinctive vanilla smell. The fruit contains tiny, flavourless seeds. In dishes prepared with whole natural vanilla, these seeds are recognizable as black specks.
Like other orchids' seeds, vanilla seed will not germinate without the presence of certain mycorrhizal fungi. Instead, growers reproduce the plant by cutting: they remove sections of the vine with six or more leaf nodes, a root opposite each leaf. The two lower leaves are removed, and this area is buried in loose soil at the base of a support. The remaining upper roots will cling to the support, and often grow down into the soil. Growth is rapid under good conditions.
# History
The first to cultivate vanilla were the Totonac people, who inhabit the Mazantla Valley on the Gulf Coast of Mexico in the present-day state of Veracruz. According to Totonac mythology, the tropical orchid was born when Princess Xanat, forbidden by her father from marrying a mortal, fled to the forest with her lover. The lovers were captured and beheaded. Where their blood touched the ground, the vine of the tropical orchid grew.[4]
In the fifteenth century, Aztecs from the central highlands of Mexico conquered the Totonacs, and the conquerors soon developed a taste for the vanilla bean. They named the bean tlilxochitl, or "black flower", after the mature bean, which shrivels and turns black shortly after it is picked. After they were subjected to the Aztecs the Totonacs paid their tribute by sending vanilla beans to the Aztec capital, Tenochtitlan.
Vanilla was completely unknown in the Old World before Columbus. Spanish explorers who arrived on the Gulf Coast of Mexico in the early sixteenth century gave vanilla its name. The Spanish and Portuguese sailors and explorers brought vanilla into Africa and Asia in the 16th century. They called it vainilla, or "little pod", The word vanilla entered the English language in the 1754, when the botanist Philip Miller wrote about the genus in his Gardener’s Dictionary.[5]
Until the mid-19th century, Mexico was the chief producer of vanilla. In 1819, however, French entrepreneurs shipped vanilla beans to the Réunion and Mauritius islands with the hope of producing vanilla there. After Edmond Albius, a 12-year-old slave from Réunion Island, discovered how to pollinate the flowers quickly by hand, the pods began to thrive. Soon the tropical orchids were sent from Réunion Island to the Comoros Islands and Madagascar along with instructions for pollinating them. By 1898, Madagascar, Réunion, and the Comoros Islands produced 200 metric tons of vanilla beans, about 80 percent of world production.[6]
The market price of vanilla rose dramatically in the late 1970s, due to a typhoon. Prices stayed stable at this level through the early 1980s despite the pressure of recently introduced Indonesian vanilla. In the mid-1980s, the cartel that had controlled vanilla prices and distribution since its creation in 1930 disbanded. Prices dropped 70 percent over the next few years, to nearly US$20 per kilo. This changed, due to typhoon Huddah, which struck early in the year 2000. The typhoon, political instability, and poor weather in the third year drove vanilla prices to an astonishing US$500 per kilo in 2004, bringing new countries into the vanilla industry. A good crop, coupled with decreased demand caused by the production of imitation vanilla, have pushed the market price down to the $40 per kilo range in the middle of 2005.
Madagascar (mostly the fertile region of Sava) accounts for half of the global production of vanilla. Mexico, once the leading producer of natural vanilla with an annual 500 tons, produced only 10 tons of vanilla in 2006. An estimated 95% of “vanilla” products actually contain artificial vanillin, produced from lignin. [7]
# Chemistry
Though there are many compounds present in the extracts of vanilla, the compound vanillin (4-hydroxy-3-methoxybenzaldehyde) is primarily responsible for the characteristic flavour and smell of vanilla. Another minor component of vanilla essential oil is piperonal (heliotropin). Piperonal and other substances affect the odour of natural vanilla. Vanillin was first isolated from vanilla pods by Gobley in 1858. By 1874, it had been obtained from glycosides of pine tree sap, temporarily causing a depression in the natural vanilla industry.
Vanilla essence comes in two forms. Real seedpod extract is an extremely complicated mixture of several hundred different compounds. Synthetic essence, consisting basically of a solution of synthetic vanillin in ethanol, is derived from phenol and is of high purity.[8]
# General production guidelines
It is well know that good vanilla will only come from good vines. In order to achieve such high quality a lot of labour has to be put on. Commercial Vanilla production can be performed under open field and “Greenhouse” operations. Both production systems share the following similarities:
- Plant height and number of years before producing the first grains
- Shade necessities
- Amount of organic matter needed
- A tree or frame to grow around it (Bamboo, coconut or Erythrina lanceolata)
- Labour intensity (pollination and harvest activities)[9]
Vanilla grows best under hot humid climate from sea level to an elevation of 1500m. Most of its production is done 10 to 20 degrees above and below the equator. The ideal growing conditions are moderate rainfall 150-300cm evenly distributed through 10 months of the year. The optimum temperatures for cultivation are 60 to 90 F during the day and 60 to 70 F during the night. Ideal humidity is around 80% and under normal greenhouse condition it can be achieved by an evaporated cooler. However, since greenhouse Vanilla is grown near the equator and under polymer (HDPE) netting (Shading of 50%) this humidity is achieved by the RH of environment.
Soils for vanilla cultivation should be loose with high organic matter content and loamy texture. They must be well drained and a slight slope helps in this condition. Soil pH has not been well documented but some researchers have indicated an optimum soil pH of around 5.3 [10]. Mulch is very important for proper growth of the vine and a considerable portion of mulch should be placed in the base of the vine. [11] Fertilization varies with soil conditions but general recommendations are: 40 to 60g of N, 20 to 30g of P2O5 and 60 to 100g of K2O should be applied to each plant per year besides organic manures like vermicompost, oil cakes, poultry manure and wood ash. Foliar applications are also good for vanilla and a solution of 1% NPK (17:17:17) can be spray in the plant once a month. Vanilla likes a lot of organic matter; therefore 3 to 4 applications of mulch a year are adequate for the plant.
Propagation, Pre-plant preparation and Type of stock
Dissemination of vanilla can be achieved either by stem cutting or by tissue culture. For stem cutting a progeny garden needs to be established. Recommendations for establishing this garden vary, but in general trenches of 60cm in width and 45 cm in depth and 60 cm spacing for each plant is necessary. All plants need to grow under 50% shade as well as the rest of the crop. Mulching the trenches with coconut husk and micro irrigation provide ideal micro climate for vegetative growth.[12] Cuttings between 60 and 120cm should be selected for planting in the field or greenhouse. Cuttings below 60 cm need to be rooted and raised in a separate nursery before planting. Planting material should always come from unflowered portions of the vine. Wilting of the cuttings before planting provides better conditions for root initiation and establishment.[13]
Before planting the cuttings, trees that will support the vine must be planted at least three months before sowing the cuttings. Pits of 30 x 30 x 30 cm are dug 30 cm away from the three and field with FYM (farm yard manure) (or Vermicompost), sand and top soil mixed well. An average of 2000 cuttings can be planted per hectare. One important consideration is that when planting the cuttings from the base 4 leaves should be pruned and the pruned basal point must be pressed into the soil in a way that the 4 nodes are in close contact with the soil and are placed at a depth of 15 to 20cm.[14] The top portion of the cutting is tied up to the tree using natural fibers like banana or hemp.
Tissue culture
Several methods have been proposed for vanilla tissue culture, but all of them begin from axillary buds of the vanilla vine.[15] [16] In vitro multiplication has also been achieved through culture of callus masses, protocorns, root tips and stem nodes.[17] Description of any of these processes can be obtained from the references listed before, but all of them are successful in generation of new vanilla plants that first need to be grown up to a height of at least 30 cm before they can be planted in the field or greenhouse.[18]
Scheduling considerations
In the tropics the ideal time for planting Vanilla is from September to November when the weather is neither to rainy or to dry; but this recommendation vary with growing conditions. Cuttings take 1 to 8 weeks to establish roots and show initial signs of growth from one of the leaf axils. A thick mulch of leaves should be provided immediately after planting as additional source of organic matter. From cuttings to produce flower and therefore pods it takes around three years. As with most orchids, the blossoms grow along stems branching from the main vine. The buds, growing along the 6 to 10 inch stems, bloom and mature in sequence, each at a different interval.[19]
Pollination
Flowering normally occurs every spring and without pollination the blossom wilts and falls, and no vanilla bean can grow. Each flower must be hand-pollinated within 12 hours of opening. The only insect capable of pollinating the blossom is the Melipona, a bee, native only to Mexico. All vanilla grown today is pollinated by hand. A small splinter of wood or a grass stem is used to lift the rostellum or moved the flap upward so that the overhanging anther can be pressed against the stigma and self pollinate the vine. Generally one flower per raceme opens per day and therefore the raceme may be in flowering for over 20 days. A healthy vine should produce about 50 to 100 beans per year; however growers are careful to pollinate only 5 to 6 flowers from the 20 on each raceme. The first 5 to 6 flowers that open per vine should be pollinated so that the beans are similar in age. These agronomic practices facilitate harvest and increases bean quality. It takes the fruits to develop 5 to 6 weeks but it takes around 9 months for the bean to mature. Over pollination will result in diseased and inferior bean quality.[20] A vine remains productive between 12 to 14 years.
Pest and disease management
Most of the diseases come from the uncharacteristic growing conditions of vanilla. Therefore conditions like excess water, insufficient drainage, heavy mulch, over pollination and too much shade favor disease development. Vanilla is susceptible to many fungal and viral diseases. Fusarium sp,Sclerotium sp, Phytopthora sp and Collectrotricum sp cause rots of root, stem, leaf, bean and shoot apex. These diseases can be controlled by spraying Bordeaux mixture (1%), Bavistin (0.2%) and Copper oxy chloride (0.2%).
Biological control of the spread of such diseases can be managed by applying to the soil Trichoderma (0.5 kg per plant in the rhizosphere) and foliar application of Pseudomonads (0.2%). Mosaic, leaf curl and Cymbidium mosaic potex virus are the common viral diseases. These diseases are transmitted through the sap; consequently affected plants have to be destroyed. The insect pests of vanilla include beetles and weevils which attack the flower, caterpillars, snakes and slugs that damage the tender parts of shoot, flower buds and immature beans and grass hoppers that affect cutting shoot tips.[21] [22] If organic agriculture is practiced, insecticides are avoided and mechanical measures are adopted for pest management. [23]. Most of these practices are implemented under greenhouse cultivation since in the field such conditions are very difficult to achieve.
# Stages of production
- Harvest[24][25] [26][27]
The vanilla bean grows quickly on the vine but is not ready for harvest until maturity- approximately nine months. Harvesting vanilla beans is as labour intensive as pollinating the blossoms. Immature dark green pods are not harvested. Pale yellow discoloration which commences at the distal end of the beans is an indication of the maturity of pods. Each bean ripens at its own time, requiring a daily harvest. To ensure the finest flavor from every bean, each individual pod must be picked by hand just as it beginning to split on the end. Over mature beans are likely to split causing a reduction in market value. Its commercial value is fixed based on the length of the pod. If the bean is more than 15 cm in length it belongs to first quality product. If the beans are between 10 to 15 cm long pods are under second quality and beans less than 10 cm in length are under third quality. Each of the beans has a considerable amount of seeds inside the pod which are covered by a dark red liquid from which the vanilla essence is extracted. Vanilla bean yield depends on the care and management given to the hanging and fruiting vines. Any practice directed to stimulate aerial root production has a direct effect on vine productivity. A five year old vine can produce between 1.5 and 3kg pods and this production can increase up to 6kg after a few years. The harvested green beans can be commercialized as such or cured in order to get a better market price
- Curing[28][29]
Several methods exist in the market for curing vanilla; nevertheless all of them consist of four basic steps: a- killing, b- sweating, c-slow drying and d- conditioning of the beans.
- Killing
The vegetative tissue of the vanilla pod is killed to prevent further growing. The method of killing varies, but may be accomplished by sun killing, oven killing, hot water killing, killing by scratching, or killing by freezing. Hot water killing consist in dipping the pods in hot water (63-65C) for three minutes to stop the vegetative growth of the pods and initiate enzymatic reactions responsible for the aroma.
- Sweating
This method consists of wrapping the beans in woolen cloth in order to raise the temperature (45-65C, under high humidity) of the beans under sunlight conditions for one hour for up to 10 days. During this time the pods are stored in wooden boxes under air tight conditions during the night. Under these conditions the beans develop the characteristic vanilla flavor, aroma and color. Its purpose is to allow enzymes to catalyze the reactions involved in generating the vanilla flavor and aroma.
- Drying
To prevent rotting and to lock the aroma in the pods, the pods are dried. Often, pods are laid out in the sun during the mornings and returned to their boxes in the afternoons. When 25-30% of the pods' weight is moisture (as opposed to the 60-70% they began drying with) they have completed the curing process and will exhibit their fullest aromatic qualities. This reduction in moisture content is achieved by spreading the beans on a wooden rack in a room for three to four weeks.
- Conditioning of the bean
This step is performed by storing the pods for a few moths in closed boxes where the fragrance develops. The processed beans are sorted, graded, bundled and wrapped in paraffin paper and preserved for the development of desired bean qualities, especially flavour and aroma. The cured vanilla beans contain an average of 2.5 % vanillin.
Grading
Once fully cured, the vanilla is sorted by quality and graded.
# Culinary uses
There are three main commercial preparations of natural vanilla:
- whole pod
- powder (ground pods, kept pure or blended with sugar, starch or other ingredients)[30]
- extract (in alcoholic solution)[31]
Vanilla flavouring in food may be achieved by adding vanilla extract or by cooking vanilla pods in the liquid preparation. A stronger aroma may be attained if the pods are split in two, exposing more of the pod's surface area to the liquid. In this case, the pods' seeds are mixed into the preparation. Natural vanilla gives a brown or yellow colour to preparations, depending on the concentration.
Good quality vanilla has a strong aromatic flavour, but food with small amounts of low quality vanilla or artificial vanilla-like flavourings are far more common, since true vanilla is much more expensive.
A major use of vanilla is in flavouring ice cream. The most common flavour of ice cream is vanilla, and thus most people consider it to be the "default" flavour. By analogy, the term "vanilla" is sometimes used as a synonym for "plain". Although vanilla is a prized flavoring agent on its own, it is also used to enhance the flavor of other substances, to which its own flavor is often complementary, such as chocolate, custard, caramel, coffee etc.
The cosmetics industry uses vanilla to make perfume.
The food industry uses methyl and ethyl vanillin. Ethyl vanillin is more expensive, but has a stronger note. Cook's Illustrated ran several taste tests pitting vanilla against vanillin in baked goods and other applications, and to the consternation of the magazine editors, tasters could not differentiate the flavour of vanillin from vanilla;[32] however, for the case of vanilla ice cream, natural vanilla won out.[33]
# Medicinal effects
In old medicinal literature, vanilla is described as an aphrodisiac and a remedy for fevers. These purported uses have never been scientifically proven, but it has been shown that vanilla does increase levels of catecholamines (including epinephrine, more commonly known as adrenaline), and as such can also be considered mildly addictive.[34][35]
In an in-vitro test vanilla was able to block quorum sensing in bacteria. This is medically interesting because in many bacteria quorum sensing signals function as a switch for virulence. The microbes only become virulent when the signals indicate that they have the numbers to resist the host immune system response.[36]
The essential oils of vanilla and vanillin are sometimes used in aromatherapy.
# Specific types of vanilla
Bourbon vanilla or Bourbon-Madagascar vanilla, produced from Vanilla planifolia plants introduced from the Americas, is the term used for vanilla from Indian Ocean islands such as Madagascar, the Comoros, and Réunion, formerly the Île Bourbon.
Mexican vanilla, made from the native Vanilla planifolia, is produced in much less quantity and marketed as the vanilla from the land of its origin. Vanilla sold in tourist markets around Mexico is sometimes not actual vanilla extract, but is mixed with an extract of the tonka bean, which contains coumarin. Tonka bean extract smells and tastes like vanilla, but coumarin has been shown to cause liver damage in lab animals and is banned in the US by the Food and Drug Administration.[37]
Tahitian vanilla is the name for vanilla from French Polynesia, made with Vanilla tahitiensis. This species is descended from V. plantifolia that was introduced to Tahiti before mutating into a distinct species.[38][dubious – discuss]
The term French vanilla is not a type of vanilla, but is often used to designate preparations that have a strong vanilla aroma, and contain vanilla grains. The name originates from the French style of making ice cream custard base with vanilla pods, cream, and egg yolks. Alternatively, French vanilla is taken to refer to a vanilla-custard flavour.[39] Syrup labelled as French vanilla may include custard, caramel or butterscotch flavours in addition to vanilla.
- A vanilla plantation in open field on Réunion.
A vanilla plantation in open field on Réunion.
- A vanilla plantation in a "shader" (ombrière) on Réunion.
A vanilla plantation in a "shader" (ombrière) on Réunion.
- Flower
Flower
- Green fruits
Green fruits | https://www.wikidoc.org/index.php/Vanilla | |
e2c726a9390727b108b18e0b61ffaf4c1170cbf4 | wikidoc | Vesicle | Vesicle
Vesicle may refer to
- Vesicle (biology), a relatively small and enclosed compartment within a cell
- Vesicular texture, a small enclosed cavity found in some volcanic rock, such as basalt
- Vesicle (adhesive tape), a blister of glue on adhesive tape that is burst when pressure is applied
- Vesicle (lipidomics), a unilamellar phospholipid liposome studied by biophysical chemists for understanding biomembranes and developing new vehicles for drug delivery
# Drug Causes
- Betamethasone dipropionate
- Betamethasone valerate
- Efinaconazole
de:Vesikel
nl:Vesicle | Vesicle
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]
Vesicle may refer to
- Vesicle (biology), a relatively small and enclosed compartment within a cell
- Vesicular texture, a small enclosed cavity found in some volcanic rock, such as basalt
- Vesicle (adhesive tape), a blister of glue on adhesive tape that is burst when pressure is applied
- Vesicle (lipidomics), a unilamellar phospholipid liposome studied by biophysical chemists for understanding biomembranes and developing new vehicles for drug delivery
## Drug Causes
- Betamethasone dipropionate
- Betamethasone valerate
- Efinaconazole
Template:Disambig
de:Vesikel
nl:Vesicle
Template:WH
Template:WikiDoc Sources
Template:Jb1 | https://www.wikidoc.org/index.php/Vesicle | |
cc56251ef8163a04bfeca24c292bb9f7f181b68e | wikidoc | Viaspan | Viaspan
Viaspan®, also known as University of Wisconsin solution (UW solution), was the first solution thoughtfully designed for use in organ transplantation, and became the first intracellular-like preservation medium. Developed by Folkert Belzer and James Southard for pancreas preservation in the late 1980s, the solution soon displaced EuroCollins solution as the preferred medium for cold storage of livers and kidneys, as well as pancreas. The solution has also been used for hearts and other organs. Viaspan remains what is often called the gold standard for organ preservation, despite the development of other solutions that are in some respects superior.
The guiding principles for the development of Viaspan were
- osmotic concentration maintained by the use of metabolically inert substances like lactobionate and raffinose rather than with glucose
- Hydroxyethyl starch (HES) is used to prevent edema
- Substances are added for to scavenge free radicals, along with steroids and insulin.
# Composition
- Potassium lactobionate: 100 mM
- KH2PO4: 25 mM
- MgSO4: 5 mM
- Raffinose: 30 mM
- Adenosine: 5 mM
- Glutathione: 3 mM
- Allopurinol: 1 mM
- Hydroxyethyl starch: 50 g/L | Viaspan
Viaspan®, also known as University of Wisconsin solution (UW solution), was the first solution thoughtfully designed for use in organ transplantation, and became the first intracellular-like preservation medium. Developed by Folkert Belzer and James Southard for pancreas preservation in the late 1980s, the solution soon displaced EuroCollins solution as the preferred medium for cold storage of livers and kidneys, as well as pancreas. The solution has also been used for hearts and other organs. Viaspan remains what is often called the gold standard for organ preservation[1], despite the development of other solutions that are in some respects superior[2].
The guiding principles for the development of Viaspan were
- osmotic concentration maintained by the use of metabolically inert substances like lactobionate and raffinose rather than with glucose
- Hydroxyethyl starch (HES) is used to prevent edema
- Substances are added for to scavenge free radicals, along with steroids and insulin.
# Composition
- Potassium lactobionate: 100 mM
- KH2PO4: 25 mM
- MgSO4: 5 mM
- Raffinose: 30 mM
- Adenosine: 5 mM
- Glutathione: 3 mM
- Allopurinol: 1 mM
- Hydroxyethyl starch: 50 g/L | https://www.wikidoc.org/index.php/Viaspan | |
343b339bfcc4a98a88a8c069d2672a6fc6191a5d | wikidoc | Vicodin | Vicodin
For drug information from the FDA, click here
# Overview
Vicodin is a trademarked brand narcotic analgesic product containing hydrocodone and paracetamol (acetaminophen or more completely para-acetylaminophenol). It is usually found in tablet form with either the names Vicodin, Vicodin ES, or Vicodin HP imprinted on one side. Analgesics with the same chemical composition and a similar physical appearance are found under many other trade names, including Anexsia, Anolor DH5, Bancap HC, Dolacet, Lorcet, Lortab, and Norco. The hydrocodone/paracetamol drug formula is also available under generic brands. The paracetamol in the formula increases the effects of the hydrocodone. Hydrocodone also comes in a combination with ibuprofen, available under the trade name Vicoprofen.
# Ingredients
Vicodin is made as a mixture of hydrocodone and paracetamol. Paracetamol, which is also called acetaminophen, acts as an analgesic/antipyretic. Hydrocodone is a synthetic mixture of the opiate codeine modified by an added hydrogen and the opiate alkaloid thebaine. Codeine acts as an antitussive, antidiarrheal and analgesic, while thebaine is added for its stimulatory effects.
- Vicodin contains 500 mg paracetamol and 5 mg hydrocodone
- Vicodin ES contains 750 mg paracetamol and 7.5 mg hydrocodone
- Vicodin HP contains 660 mg paracetamol and 10 mg hydrocodone
Non-active ingredients included in each pill as well: colloidal silicon dioxide, starch, croscarmellose sodium, dibasic calcium phosphate, magnesium stearate, microcrystalline cellulose, povidone, and stearic acid.
# Regulation and scheduling
In the United States, Vicodin production is regulated in part by the Controlled Substances Act of 1970. This guarantees that all manufacturing, importing, possession, and distribution of drugs is to be overseen and regulated by the federal government.
In the U.S. Hydrocodone is a Schedule III drug. Other drugs on this list include anabolic steroids, dihydrocodeine, dronabinol, phendimetrazine, ketamine, paregoric, and Xyrem; codeine and hydrocodone are also Schedule III but only when compounded with paracetamol or with an NSAID. Schedule III drugs are classified by the U.S. government as potentially causing moderate or low physical dependence or a high psychological dependence if abused. There is a high inclination for abuse of this drug.
# Manufacture
The principal constituent of Vicodin, hydrocodone, has the same basic structure as morphine but is metabolized by different enzymes. There are three variations of Vicodin, with different amounts of hydrocodone / paracetamol (acetaminophen) in each. Hydrocodone is a strong drug which has similar effects as morphine, because of this, the pills are made with much less hydrocodone than paracetamol. The theory of using the mix comes from the idea that these drugs alleviate pain using different mechanisms and also that the adverse side effects of each separate drug are reduced by using reduced dosages of both drugs in order to get the same analgesic effect. Both hydrocodone and acetaminophen are white crystalline powders, which are then manufactured into pill form. There is also a theory that the acetaminophen is added in order to reduce abuse potential, as multiple doses will result in nausea symptoms and stomach complications.
Manufacturers of hydrocodone (generic or otherwise) include Abbott Laboratories (makers of trademark Vicodin), Amerisource Health Services Corp, Cardinal Health, Drx Pharmaceutical Consultants Inc, Eckerd Corp, Hospira Inc, Knoll Laboratories Div Knoll Pharmaceutical Co, Mallinckrodt Pharm. Quality Care, Pdrx Pharmaceuticals Inc, Physicians Total Care Inc, Rx Pak Div of Mckesson Corp, Sandhills Packaging Inc, and Watson Pharmaceuticals.
# Pharmacokinetics
Besides the activity of hydrocodone and acetaminophen on their own, there is observed a factor of analgesia related to the two substances in tandem which is not altogether understood, but this independent synergy has been observed to be related to the inhibition of prostaglandins. The pharmacokinetics of a mixed drug such as Vicodin depends on the kinetics of the drugs that comprise it. We will look at the two main constituents separately, hydrocodone and paracetamol.
Hydrocodone: acts at mu opioid receptors. Hydrocodone must be metabolized to its active state, hydromorphone. This metabolism occurs by the activity of cytochrome P450 2D6. Cytochrome 3A4 forms the active substrate norhydrocodone. Cytochromes are haemoprotiens found in the cells of all living organisms and are involved primarily with the electron transport chain producing ATP. Hydrocodone passes through the Blood Brain Barrier because of its modifications, the brain is typically where the analgesic effects are being carried out. Many of the side effects of this drug are caused by the fact that it so readily crosses the BBB. The half-life of hydrocodone is approximately 3.8 hrs. Paracetamol: the major active metabolites are sulphates and glucuronide conjugates. Its main mode of action is to inhibit the activity of the enzyme cyclooxygenase (COX). COX enzymes are necessary for the production of prostaglandins. Prostaglandins are a form of hormone (although rarely classified as such), which are indicated to be mediators of pain, fever and inflammation. The half-life of paracetamol may be measured either by salivary or plasma counts. Both measurements give a varying half-life between 1 and 4 hours. Peak levels are reached between 40–60 minutes after ingestion. It has been proposed that paracetamol aids in the reduction of pain by increasing seratonergic neurotransmissions. Paracetamol is a peripherally acting drug, and hence does not cross the BBB as readily as hydrocodone.
# Indications
Vicodin, like other opioid analgesics, is used to manage pain. It is most commonly prescribed for relief of moderate to moderately severe pain of acute, chronic, or post-operative types. It can also be used to treat severe cough.
# Pregnancy
This drug is classified under pregnancy category C. Although not enough research has been done to deem this drug safe for pregnant women, if the positive effects outweigh the possible negatives, then it can be taken. If taken in the time before delivery, it may give rise to respiratory depression in the baby. Mothers who use any opioids regularly during pregnancy run the risk of their babies being substance dependent and therefore going through withdrawal symptoms after birth. Withdrawal symptoms include: excessive crying, vomiting, irritability, tremors and fever. Nursing mothers should not use this drug as paracetamol is transferred through breast milk and it is unknown if hydrocodone is.
# Side effects
Side effects for Vicodin are most commonly upset stomach, nausea, and altered mental status (eg. dizziness, light headedness). Other more rare side effects include allergic reaction, seizures, clammy skin, hallucinations, severe weakness, dizziness, hyperventilation, unconsciousness, jaundice (yellowing of eyes or skin), unusual fatigue, bleeding, bruising, stomach pain, constipation, dry mouth, decreased appetite, muscle twitches, sweating, hot flashes, itching, tinnitus, hearing loss, decreased urination, and altered sex drive. Vicodin also has depressant effects on the central nervous system. However, some of the less mundane effects can be desirable effects that are sought after by some. Those effects include euphoria and drowsiness, as well as slowing of the pulse. Unlike NSAIDs, Paracetamol does not cause ulcers. Liver damage can manifest ranging from abdominal pain to outright liver failure, and can necessitate a liver transplant to avoid death. Paracetamol dosages should never exceed 4g a day; this is especially important and may be a smaller number when dealing with mixed drugs like Vicodin. It is imperative that users of this drug follow physician prescribed dosages.
# Behavioral effects
Tolerance to this drug may develop rapidly, especially if it is misused. This tolerance will usually manifest itself by analgesic effects wearing off faster, and people needing higher dosages to reach the analgesic effects. It is commonly misused or used excessively because people take too much in order to relieve their pain faster. Taking more of the drug does increase its efficacy but it also increases its addictive properties. When tolerance does develop, people are often forced to seek out more and more Vicodin, but as it is a controlled substance, there are regulations on how much can be legally prescribed. This often leads to societal/legal consequences as people will visit many doctors and/or try to buy the drug illegally. The withdrawal effects of Vicodin include things such as insomnia, night sweats, tremors, and agitation. People looking for the secondary effects of the drug often abuse many forms of prescription drugs. Vicodin is a potentially addictive drug, specifically due to the hydrocodone in it. People who are using Vicodin for non-medicinal purposes are typically using it to get the euphoric effects sometimes associated with it. Ten percent of American high school seniors have abused Vicodin; 4.7 percent report abusing Oxycontin in the past year. There have been reports of severe hearing loss and deafness associated with the abuse of Vicodin. If taken at the normal prescribed dosages, the risk of hearing loss is very minimal. It is interesting to note that in people who use these drugs for recreational purposes there are sex differences. Women tend to feel less "in control on their thoughts" and more report, "feeling bad" more often than men. People given logic examinations while under the influence of this drug showed an increase in incorrect answers, but spent more time on the exams. This suggests that this drug may be aiding in attention. It is again important to note that clinically prescribed dosages do not produce these effects; these effects are related to taking more of the drug than typically prescribed.
# Paracetamol/Acetaminophen In The News
On Jun 30 2009 an FDA advisory panel recommended that Vicodin and another painkiller, Percocet, be removed from the market because they have allegedly caused over 400 deaths a year. The problem is with Paracetamol overdose and liver damage. | Vicodin
For drug information from the FDA, click here
# Overview
Vicodin is a trademarked brand narcotic analgesic product containing hydrocodone and paracetamol (acetaminophen or more completely para-acetylaminophenol). It is usually found in tablet form with either the names Vicodin, Vicodin ES, or Vicodin HP imprinted on one side. Analgesics with the same chemical composition and a similar physical appearance are found under many other trade names, including Anexsia, Anolor DH5, Bancap HC, Dolacet, Lorcet, Lortab, and Norco. The hydrocodone/paracetamol drug formula is also available under generic brands. The paracetamol in the formula increases the effects of the hydrocodone. Hydrocodone also comes in a combination with ibuprofen, available under the trade name Vicoprofen.
# Ingredients
Vicodin is made as a mixture of hydrocodone and paracetamol. Paracetamol, which is also called acetaminophen, acts as an analgesic/antipyretic. Hydrocodone is a synthetic mixture of the opiate codeine modified by an added hydrogen and the opiate alkaloid thebaine. Codeine acts as an antitussive, antidiarrheal and analgesic, while thebaine is added for its stimulatory effects.
- Vicodin contains 500 mg paracetamol and 5 mg hydrocodone
- Vicodin ES contains 750 mg paracetamol and 7.5 mg hydrocodone
- Vicodin HP contains 660 mg paracetamol and 10 mg hydrocodone
Non-active ingredients included in each pill as well: colloidal silicon dioxide, starch, croscarmellose sodium, dibasic calcium phosphate, magnesium stearate, microcrystalline cellulose, povidone, and stearic acid.[1]
# Regulation and scheduling
In the United States, Vicodin production is regulated in part by the Controlled Substances Act of 1970. This guarantees that all manufacturing, importing, possession, and distribution of drugs is to be overseen and regulated by the federal government.
In the U.S. Hydrocodone is a Schedule III drug. Other drugs on this list include anabolic steroids, dihydrocodeine, dronabinol, phendimetrazine, ketamine, paregoric, and Xyrem; codeine and hydrocodone are also Schedule III but only when compounded with paracetamol or with an NSAID. Schedule III drugs are classified by the U.S. government as potentially causing moderate or low physical dependence or a high psychological dependence if abused. There is a high inclination for abuse of this drug.
# Manufacture
The principal constituent of Vicodin, hydrocodone, has the same basic structure as morphine but is metabolized by different enzymes. There are three variations of Vicodin, with different amounts of hydrocodone / paracetamol (acetaminophen) in each. Hydrocodone is a strong drug which has similar effects as morphine, because of this, the pills are made with much less hydrocodone than paracetamol. The theory of using the mix comes from the idea that these drugs alleviate pain using different mechanisms and also that the adverse side effects of each separate drug are reduced by using reduced dosages of both drugs in order to get the same analgesic effect.[2] Both hydrocodone and acetaminophen are white crystalline powders, which are then manufactured into pill form. There is also a theory that the acetaminophen is added in order to reduce abuse potential, as multiple doses will result in nausea symptoms and stomach complications.
Manufacturers of hydrocodone (generic or otherwise) include Abbott Laboratories (makers of trademark Vicodin), Amerisource Health Services Corp, Cardinal Health, Drx Pharmaceutical Consultants Inc, Eckerd Corp, Hospira Inc, Knoll Laboratories Div Knoll Pharmaceutical Co, Mallinckrodt Pharm. Quality Care, Pdrx Pharmaceuticals Inc, Physicians Total Care Inc, Rx Pak Div of Mckesson Corp, Sandhills Packaging Inc, and Watson Pharmaceuticals.
# Pharmacokinetics
Besides the activity of hydrocodone and acetaminophen on their own, there is observed a factor of analgesia related to the two substances in tandem which is not altogether understood, but this independent synergy has been observed to be related to the inhibition of prostaglandins. The pharmacokinetics of a mixed drug such as Vicodin depends on the kinetics of the drugs that comprise it. We will look at the two main constituents separately, hydrocodone and paracetamol.
Hydrocodone: acts at mu opioid receptors.[3] Hydrocodone must be metabolized to its active state, hydromorphone. This metabolism occurs by the activity of cytochrome P450 2D6. Cytochrome 3A4 forms the active substrate norhydrocodone. Cytochromes are haemoprotiens found in the cells of all living organisms and are involved primarily with the electron transport chain producing ATP. Hydrocodone passes through the Blood Brain Barrier because of its modifications, the brain is typically where the analgesic effects are being carried out. Many of the side effects of this drug are caused by the fact that it so readily crosses the BBB. The half-life of hydrocodone is approximately 3.8 hrs. Paracetamol: the major active metabolites are sulphates and glucuronide conjugates. Its main mode of action is to inhibit the activity of the enzyme cyclooxygenase (COX). COX enzymes are necessary for the production of prostaglandins. Prostaglandins are a form of hormone (although rarely classified as such), which are indicated to be mediators of pain, fever and inflammation. The half-life of paracetamol may be measured either by salivary or plasma counts. Both measurements give a varying half-life between 1 and 4 hours.[4] Peak levels are reached between 40–60 minutes after ingestion. It has been proposed that paracetamol aids in the reduction of pain by increasing seratonergic neurotransmissions.[5] Paracetamol is a peripherally acting drug, and hence does not cross the BBB as readily as hydrocodone.
# Indications
Vicodin, like other opioid analgesics, is used to manage pain. It is most commonly prescribed for relief of moderate to moderately severe pain of acute, chronic, or post-operative types. It can also be used to treat severe cough.
# Pregnancy
This drug is classified under pregnancy category C. Although not enough research has been done to deem this drug safe for pregnant women, if the positive effects outweigh the possible negatives, then it can be taken. If taken in the time before delivery, it may give rise to respiratory depression in the baby. Mothers who use any opioids regularly during pregnancy run the risk of their babies being substance dependent and therefore going through withdrawal symptoms after birth. Withdrawal symptoms include: excessive crying, vomiting, irritability, tremors and fever. Nursing mothers should not use this drug as paracetamol is transferred through breast milk and it is unknown if hydrocodone is. [6]
# Side effects
Side effects for Vicodin are most commonly upset stomach, nausea, and altered mental status (eg. dizziness, light headedness). Other more rare side effects include allergic reaction, seizures, clammy skin, hallucinations, severe weakness, dizziness, hyperventilation, unconsciousness, jaundice (yellowing of eyes or skin), unusual fatigue, bleeding, bruising, stomach pain[8], constipation, dry mouth, decreased appetite, muscle twitches, sweating, hot flashes, itching, tinnitus, hearing loss, decreased urination, and altered sex drive. Vicodin also has depressant effects on the central nervous system. However, some of the less mundane effects can be desirable effects that are sought after by some. Those effects include euphoria and drowsiness, as well as slowing of the pulse. Unlike NSAIDs, Paracetamol does not cause ulcers. Liver damage can manifest ranging from abdominal pain to outright liver failure, and can necessitate a liver transplant to avoid death. Paracetamol dosages should never exceed 4g a day; this is especially important and may be a smaller number when dealing with mixed drugs like Vicodin. It is imperative that users of this drug follow physician prescribed dosages.
# Behavioral effects
Tolerance to this drug may develop rapidly, especially if it is misused. This tolerance will usually manifest itself by analgesic effects wearing off faster, and people needing higher dosages to reach the analgesic effects. It is commonly misused or used excessively because people take too much in order to relieve their pain faster. Taking more of the drug does increase its efficacy but it also increases its addictive properties. When tolerance does develop, people are often forced to seek out more and more Vicodin, but as it is a controlled substance, there are regulations on how much can be legally prescribed. This often leads to societal/legal consequences as people will visit many doctors and/or try to buy the drug illegally. The withdrawal effects of Vicodin include things such as insomnia, night sweats, tremors, and agitation.[9] People looking for the secondary effects of the drug often abuse many forms of prescription drugs. Vicodin is a potentially addictive drug, specifically due to the hydrocodone in it. People who are using Vicodin for non-medicinal purposes are typically using it to get the euphoric effects sometimes associated with it. Ten percent of American high school seniors have abused Vicodin; 4.7 percent report abusing Oxycontin in the past year.[10] There have been reports of severe hearing loss and deafness associated with the abuse of Vicodin. [11] If taken at the normal prescribed dosages, the risk of hearing loss is very minimal. It is interesting to note that in people who use these drugs for recreational purposes there are sex differences. Women tend to feel less "in control on their thoughts" and more report, "feeling bad" more often than men. People given logic examinations while under the influence of this drug showed an increase in incorrect answers, but spent more time on the exams. This suggests that this drug may be aiding in attention. It is again important to note that clinically prescribed dosages do not produce these effects; these effects are related to taking more of the drug than typically prescribed.[3]
# Paracetamol/Acetaminophen In The News
On Jun 30 2009 an FDA advisory panel recommended that Vicodin and another painkiller, Percocet, be removed from the market because they have allegedly caused over 400 deaths a year. The problem is with Paracetamol overdose and liver damage.[12] | https://www.wikidoc.org/index.php/Vicodin | |
3c9c398f7018b7efc3ba9e1d716d9f0057e8e698 | wikidoc | Viminol | Viminol
# Overview
Viminol (marketed under the brandname Dividol) is a drug which is an opioid analgesic. It has an unusual chemical structure that is not similar to other opioids.
Viminol has both antitussive (cough suppressing) and analgesic (pain reducing) effects. It has six different stereoisomers which have varying properties, with the R2 isomer being a μ-opioid full agonist slightly more potent than morphine, while the S2 isomer is an antagonist. Since vimonol is supplied as a racemic mixture of isomers, the overall effect produces a mixed agonist-antagonist profile similar to that of opioids such as pentazocine, although with somewhat less side effects.
Viminol has similar effects to other opioids, and produces analgesia, sedation and euphoria.
# Side Effects
Side effects are similar to other opiods, and can include:
- Itching
- Nausea
- Sedation
- Respiratory depression - can be potentially life-threatening
However, since viminol is supplied as a racemic mixture of agonist and antagonist isomers, the abuse potential and respiratory depression tends to be less than that of μ-opioid full agonist drugs. | Viminol
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]
# Overview
Viminol (marketed under the brandname Dividol) is a drug which is an opioid analgesic. It has an unusual chemical structure that is not similar to other opioids.[1][2]
Viminol has both antitussive (cough suppressing) and analgesic (pain reducing) effects. It has six different stereoisomers which have varying properties, with the R2 isomer being a μ-opioid full agonist slightly more potent than morphine, while the S2 isomer is an antagonist.[3] Since vimonol is supplied as a racemic mixture of isomers, the overall effect produces a mixed agonist-antagonist profile similar to that of opioids such as pentazocine, although with somewhat less side effects.[4]
Viminol has similar effects to other opioids, and produces analgesia, sedation and euphoria.
# Side Effects
Side effects are similar to other opiods, and can include:
- Itching
- Nausea
- Sedation
- Respiratory depression - can be potentially life-threatening
However, since viminol is supplied as a racemic mixture of agonist and antagonist isomers, the abuse potential and respiratory depression tends to be less than that of μ-opioid full agonist drugs. | https://www.wikidoc.org/index.php/Viminol | |
3072ef8578616b0fe2637dc5505b80190828e708 | wikidoc | Viperin | Viperin
Viperin (Virus inhibitory protein, endoplasmic reticulum-associated, interferon-inducible), also known as RSAD2 (radical SAM domain-containing 2), is a multifunctional protein in viral processes, which could be induced in a variety of cell types by different cellular factors, such as type I II and III interferon, DNA and RNA viral proteins, poly (I: C) and polysaccharide. Recently, it is reported that viperin could be induced in either IFN-dependent or IFN-independent pathway.
# Function
Viperin is a cellular protein which could inhibit many DNA and RNA viruses such as CHIKV, HCMV, HCV, DENV, WNV, SINV, influenza, HIV LAI strain, and so on.
Initially identified as an IFN-γ induced antiviral protein in human cytomegalovirus (HCMV) infected macrophages, viperin is reported that it could be induced by HCMV glycoprotein B in fibroblasts but inhibits HCMV viral infection and down-regulates viral structural proteins, which is essential for viral assembling and maturation. The mechanism of how the virus protein induces viperin against itself is still not clear. However, the viral induced redistribution of Viperin is also found in HCMV infected cells, which may reflect the mechanism of virus evading antiviral activities of Viperin. Viperin could also be induced, and then interact with HCMV viral proteins and relocate to mitochondria in HCMV viral infected cells, and finally enhance viral infectivity by the disrupted cellular metabolism.
In the inhibition of influenza virus budding and release, viperin could disrupt the lipid rafts on cell plasma membrane by decreasing the enzyme activities of farnesyl diphosphate synthase (FPPS), which is an essential enzyme in isoprenoid biosynthesis pathway. Besides, viperin can also inhibit the viral replication of HCV via the interaction with host protein hVAP-33 and NS5A and disruption of the formation of the replication complex.
# Structure
Human Viperin consists of 361 amino acids, and it is a single polypeptide chain with a predicted 42kDa molecular mass. The first 42 residues of human viperin is the N-terminal amphipathic alpha-helix, which is relatively less conserved in different species and has a minor effect on the antiviral ability of viperin against HCV, WNV and DENV. The N-terminal domain of viperin is also required for the viperin localization in ER and the lipid droplets. The residues 77-209 constitute the radical S-adenosylmethionine (SAM) domain, in which there are four conserved motifs. Motif 1 contains three conserved cysteine residues, CxxCxxC, which is the Fe-S binding motif and also essential for the antiviral activities against HCV and HCMV infections.
The 218-361 residues constitute the C-terminal domain of viperin, which is highly conserved in different species of viperin and essential for viperin dimerization. The last residue 361 of the C-terminal, a tryptophan, is essential for the antiviral activities against HCV since a C-terminal flag tagged of viperin lost its antiviral activities.
Viperin forms homodimers in ER, and the over expression of viperin could lead the formation of a crystalloid ER.
# Cellular localization
Viperin is normally localized in endoplasmic reticulum (ER) via its N-terminal domain, and also localized to lipid droplet, which is derived from ER. However, it is also found in mitochondria in the HCMV infected fibroblasts by a viral mediated mechanism. | Viperin
Viperin (Virus inhibitory protein, endoplasmic reticulum-associated, interferon-inducible),[1] also known as RSAD2 (radical SAM domain-containing 2), is a multifunctional protein in viral processes, which could be induced in a variety of cell types by different cellular factors, such as type I II and III interferon, DNA and RNA viral proteins, poly (I: C) and polysaccharide. Recently, it is reported that viperin could be induced in either IFN-dependent or IFN-independent pathway.
# Function
Viperin is a cellular protein which could inhibit many DNA and RNA viruses such as CHIKV, HCMV, HCV, DENV, WNV, SINV, influenza, HIV LAI strain, and so on.[2]
Initially identified as an IFN-γ induced antiviral protein in human cytomegalovirus (HCMV) infected macrophages, viperin is reported that it could be induced by HCMV glycoprotein B in fibroblasts but inhibits HCMV viral infection and down-regulates viral structural proteins, which is essential for viral assembling and maturation. The mechanism of how the virus protein induces viperin against itself is still not clear. However, the viral induced redistribution of Viperin is also found in HCMV infected cells, which may reflect the mechanism of virus evading antiviral activities of Viperin.[3] Viperin could also be induced, and then interact with HCMV viral proteins and relocate to mitochondria in HCMV viral infected cells, and finally enhance viral infectivity by the disrupted cellular metabolism.[4]
In the inhibition of influenza virus budding and release, viperin could disrupt the lipid rafts on cell plasma membrane by decreasing the enzyme activities of farnesyl diphosphate synthase (FPPS), which is an essential enzyme in isoprenoid biosynthesis pathway.[5] Besides, viperin can also inhibit the viral replication of HCV via the interaction with host protein hVAP-33 and NS5A and disruption of the formation of the replication complex.[6]
# Structure
Human Viperin consists of 361 amino acids, and it is a single polypeptide chain with a predicted 42kDa molecular mass. The first 42 residues of human viperin is the N-terminal amphipathic alpha-helix, which is relatively less conserved in different species and has a minor effect on the antiviral ability of viperin against HCV, WNV and DENV. The N-terminal domain of viperin is also required for the viperin localization in ER and the lipid droplets.[7] The residues 77-209 constitute the radical S-adenosylmethionine (SAM) domain, in which there are four conserved motifs. Motif 1 contains three conserved cysteine residues, CxxCxxC, which is the Fe-S binding motif and also essential for the antiviral activities against HCV and HCMV infections.[4]
The 218-361 residues constitute the C-terminal domain of viperin, which is highly conserved in different species of viperin and essential for viperin dimerization. The last residue 361 of the C-terminal, a tryptophan, is essential for the antiviral activities against HCV since a C-terminal flag tagged of viperin lost its antiviral activities.[8]
Viperin forms homodimers in ER, and the over expression of viperin could lead the formation of a crystalloid ER.
# Cellular localization
Viperin is normally localized in endoplasmic reticulum (ER) via its N-terminal domain, and also localized to lipid droplet, which is derived from ER.[7] However, it is also found in mitochondria in the HCMV infected fibroblasts by a viral mediated mechanism.[4] | https://www.wikidoc.org/index.php/Viperin | |
67adeb1d4524655641529738f109c71943d3eea0 | wikidoc | Viremia | Viremia
# Overview
Viremia is a medical condition where viruses enter the bloodstream and hence have access to the rest of the body. It is similar to bacteremia, a condition where bacteria enter the bloodstream. The name comes from combining the word virus with the Greek word for blood (haima).
# Primary versus Secondary
Primary viremia refers to the initial spread of virus in the blood from the first site of infection.
Secondary viremia occurs when primary viremia has resulted in infection of additional tissues via bloodstream, in which the virus has replicated and once more entered the circulation.
Usually secondary viremia results in higher viral shedding and viral loads within the bloodstream due to the possibility that the virus is able to reach its natural host cell from the bloodstream and replicate more efficiently than the initial site. An excellent example to profile this distinction is the rabies virus. Usually the virus will replicate briefly within the first site of infection, within the muscle tissues. Viral replication then leads to viremia and the virus spreads to its secondary site of infection, the Central nervous system (CNS). Upon infection of the CNS, secondary viremia results and symptoms usually begin. Vaccination at this point is useless, as the spread to the brain is unstoppable. Vaccination must be done before secondary viremia takes place for the individual to avoid brain damage or death.
# Active versus Passive
Active viremia is caused by the replication of viruses which results in viruses being introduced into the bloodstream. Examples include the measles, in which primary viremia occurs in the epithelial lining of the respiratory tract before replicating and budding out of the cell basal layer (viral shedding), resulting in viruses budding into capillaries and blood vessels.
Passive viremia is the introduction of viruses in the bloodstream without the need of active viral replication. Examples include direct inoculation from mosquitoes, through physical breaches or via blood transfusions. | Viremia
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]
# Overview
Viremia is a medical condition where viruses enter the bloodstream and hence have access to the rest of the body. It is similar to bacteremia, a condition where bacteria enter the bloodstream.[1] The name comes from combining the word virus with the Greek word for blood (haima).
# Primary versus Secondary
Primary viremia refers to the initial spread of virus in the blood from the first site of infection.
Secondary viremia occurs when primary viremia has resulted in infection of additional tissues via bloodstream, in which the virus has replicated and once more entered the circulation.
Usually secondary viremia results in higher viral shedding and viral loads within the bloodstream due to the possibility that the virus is able to reach its natural host cell from the bloodstream and replicate more efficiently than the initial site.[2] An excellent example to profile this distinction is the rabies virus.[3] Usually the virus will replicate briefly within the first site of infection, within the muscle tissues. Viral replication then leads to viremia and the virus spreads to its secondary site of infection, the Central nervous system (CNS). Upon infection of the CNS, secondary viremia results and symptoms usually begin.[4] Vaccination at this point is useless, as the spread to the brain is unstoppable. Vaccination must be done before secondary viremia takes place for the individual to avoid brain damage or death.
# Active versus Passive
Active viremia is caused by the replication of viruses which results in viruses being introduced into the bloodstream. Examples include the measles, in which primary viremia occurs in the epithelial lining of the respiratory tract before replicating and budding out of the cell basal layer (viral shedding), resulting in viruses budding into capillaries and blood vessels.[5]
Passive viremia is the introduction of viruses in the bloodstream without the need of active viral replication. Examples include direct inoculation from mosquitoes, through physical breaches or via blood transfusions.[6] | https://www.wikidoc.org/index.php/Viraemia | |
45961e6fef1787db1269dd84cc5771ff505cec39 | wikidoc | Vitamer | Vitamer
The vitamers of a particular vitamin are all of the chemical compounds which exhibit vitamin activity. Very commonly "vitamins" are not single compounds, but rather each vitamin, which is defined by its biological activity, not its structure, is actually represented by a number of substances, all of which show vitamin activity. Typically, the vitamin activity of multiple vitamers is due to the body's limited ability to convert one vitamer to another, or many vitamers to the same enzymatic cofactor(s). This is the case even though (as part of the definition of vitamin) the body cannot completely synthesize an optimal amount of vitamin activity from simple foodstuffs, without a minimal vitamer molecule as a basis.
Typically not all vitamers possess exactly the same vitamin potency, per mass. This is due to differences in absorption and interconversion of the various different vitamers of a vitamin. Often for the same reason, the toxicity of vitamers varies by molecule, as is the case with vitamin E.
A set of chemicals may be (but is not always) grouped under an alphabetized vitamin "generic descriptor" title, such as "vitamin A," which (for example) includes retinal, retinol, and many carotenoids. Examples of vitamers include cyanocobalamin, hydroxocobalamin, methylcobalamin, and 5-deoxyadenosylcobalamin (adenosylcobalamin—AdoB-12), which are all vitamers of B-12, and thus all possess "B-12 activity". Another example is that both niacinamide and nicotinic acid (niacin) have vitamin B-3 activity.
Some vitamins have not been given specific alphabetic generic descriptors by naming commissions, and continue to be known by names like biotin and folate (which are B vitamins but have no B number). However, even these vitamins consist of various different active vitamers in both foods and in cellular function. | Vitamer
The vitamers of a particular vitamin are all of the chemical compounds which exhibit vitamin activity. Very commonly "vitamins" are not single compounds, but rather each vitamin, which is defined by its biological activity, not its structure, is actually represented by a number of substances, all of which show vitamin activity.[1] Typically, the vitamin activity of multiple vitamers is due to the body's limited ability to convert one vitamer to another, or many vitamers to the same enzymatic cofactor(s). This is the case even though (as part of the definition of vitamin) the body cannot completely synthesize an optimal amount of vitamin activity from simple foodstuffs, without a minimal vitamer molecule as a basis.
Typically not all vitamers possess exactly the same vitamin potency, per mass. This is due to differences in absorption and interconversion of the various different vitamers of a vitamin. Often for the same reason, the toxicity of vitamers varies by molecule, as is the case with vitamin E.[2]
A set of chemicals may be (but is not always) grouped under an alphabetized vitamin "generic descriptor" title, such as "vitamin A," which (for example) includes retinal, retinol, and many carotenoids. [3] Examples of vitamers include cyanocobalamin, hydroxocobalamin, methylcobalamin, and 5-deoxyadenosylcobalamin (adenosylcobalamin—AdoB-12), which are all vitamers of B-12, and thus all possess "B-12 activity". Another example is that both niacinamide and nicotinic acid (niacin) have vitamin B-3 activity.
Some vitamins have not been given specific alphabetic generic descriptors by naming commissions, and continue to be known by names like biotin and folate (which are B vitamins but have no B number). However, even these vitamins consist of various different active vitamers in both foods and in cellular function.
# External links
- Dictonary definition of vitamer. Refererenced Jan. 4, 2008 | https://www.wikidoc.org/index.php/Vitamer | |
48e77d9dba5a89cd6dcc162971765ed2a9bdf96e | wikidoc | Vitamin | Vitamin
# Overview
A vitamin is an organic compound required as a nutrient in tiny amounts by an organism. A compound is called a vitamin when it cannot be synthesized in sufficient quantities by an organism, and must be obtained from the diet. Thus, the term is conditional both on the circumstances and the particular organism. For example, ascorbic acid functions as vitamin C for some animals but not others, and vitamins D and K are required in the human diet only in certain circumstances. Vitamins are defined by their biological activity, not their structure. Thus, each "vitamin" actually refers to a number of vitamer compounds, which form a set of distinct chemical compounds that show the biological activity of a particular vitamin. Such a set of chemicals are grouped under an alphabetized vitamin "generic descriptor" title, such as "vitamin A," which (for example) includes retinal, retinol, and many carotenoids. Vitamers are often inter-convertible in the body. The term vitamin does not include other essential nutrients such as dietary minerals, essential fatty acids, or essential amino acids, nor does it encompass the large number of other nutrients that promote health but that are not essential for life.
Vitamins have diverse biochemical functions, including function as hormones (e.g. vitamin D), antioxidants (e.g. vitamin E), and mediators of cell signaling and regulators of cell and tissue growth and differentiation (e.g. vitamin A) . The largest number of vitamins (e.g. B complex vitamins) function as precursors for enzyme cofactor bio-molecules (coenzymes), that help act as catalysts and substrates in metabolism. When acting as part of a catalyst, vitamins are bound to enzymes and are called prosthetic groups. For example, biotin is part of enzymes involved in making fatty acids. Vitamins also act as coenzymes to carry chemical groups between enzymes. For example, folic acid carries various forms of carbon group – methyl, formyl and methylene - in the cell. Although these roles in assisting enzyme reactions are vitamins' best-known function, the other vitamin functions are equally important.
Until the 1800s, vitamins were obtained solely through food intake, and changes in diet (which, for example, could occur during a particular growing season) can alter the types and amounts of vitamins ingested. Vitamins have been produced as commodity chemicals and made widely available as inexpensive pills for several decades, allowing supplementation of the dietary intake.
# History
The value of eating certain foods to maintain health was recognized long before vitamins were identified. The ancient Egyptians knew that feeding a patient liver would help cure night blindness, an illness now known to be caused by a vitamin A deficiency. The advancement of ocean voyage during the Renaissance resulted in prolonged periods without access to fresh fruits and vegetables, and made illnesses from vitamin deficiency common among ship's crew.
In 1749, the Scottish surgeon James Lind discovered that citrus foods helped prevent scurvy, a particularly deadly disease in which collagen is not properly formed, causing poor wound healing, bleeding of the gums, severe pain, and death. In 1753, Lind published his Treatise on the Scurvy, which recommended using lemons and limes to avoid scurvy, which was adopted by the British Royal Navy. This led to the nickname Limey for sailors of that organization. Lind's discovery, however, was not widely accepted by individuals in the Royal Navy's Arctic expeditions in the 19th century, where it was widely believed that scurvy could be prevented by practicing good hygiene, regular exercise, and by maintaining the morale of the crew while on board, rather than by a diet of fresh food. As a result, Arctic expeditions continued to be plagued by scurvy and other deficiency diseases. In the early 20th century, when Robert Falcon Scott made his two expeditions to the Antarctic, the prevailing medical theory was that scurvy was caused by "tainted" canned food.
In 1881, Russian surgeon Nikolai Lunin studied the effects of scurvy while at the University of Tartu in present-day Estonia. He fed mice an artificial mixture of all the separate constituents of milk known at that time, namely the proteins, fats, carbohydrates, and salts. The mice that received only the individual constituents died, while the mice fed by milk itself developed normally. He made a conclusion that "a natural food such as milk must therefore contain, besides these known principal ingredients, small quantities of unknown substances essential to life". However, his conclusions were rejected by other researchers when they were unable to reproduce his results. One difference was that he had used table sugar (sucrose), while other researchers had used milk sugar (lactose) that still contained small amounts of vitamin B.
In the Orient where polished white rice was the common staple food of the middle class, beriberi resulting from lack of vitamin B was endemic. In 1884, Takaki Kanehiro, a British trained medical doctor of the Japanese Navy observed that beriberi was endemic among low ranking crew who often ate nothing but rice but not among crews of Western navies and officers who were entitled to a Western-style diet. Kanehiro initially believed that lack of protein was the chief cause of beriberi. With the support of Japanese navy, he experimented using crews of two battleships, one crew was fed only white rice, while the other was fed a diet of meat, fish, barley, rice, and beans. The group that ate only white rice documented 161 crew with beriberi and 25 deaths, while the latter group had only 14 cases of beriberi and no deaths. This convinced Kanehiro and the Japanese Navy that diet was the cause of beriberi. This was confirmed in 1897, when Christiaan Eijkman discovered that feeding unpolished rice instead of the polished variety to chickens helped to prevent beriberi in the chickens. The following year, Frederick Hopkins postulated that some foods contained "accessory factors"—in addition to proteins, carbohydrates, fats, et cetera—that were necessary for the functions of the human body. Hopkins was awarded the 1929 Nobel Prize for Physiology or Medicine with Christiaan Eijkman for their discovery of several vitamins.
In 1910, Japanese scientist Umetaro Suzuki succeeded in extracting a water-soluble complex of micronutrients from rice bran and named it aberic acid. He published this discovery in a Japanese scientific journal.
When the article was translated into German, the translation failed to state that it was a newly discovered nutrient, a claim made in the original Japanese article, and hence his discovery failed to gain publicity. Polish biochemist Kazimierz Funk isolated the same complex of micronutrients and proposed the complex be named "Vitamine" (a portmanteau of "vital amine") in 1912. The name soon became synonymous with Hopkins' "accessory factors", and by the time it was shown that not all vitamins were amines, the word was already ubiquitous. In 1920, Jack Cecil Drummond proposed that the final "e" be dropped to deemphasize the "amine" reference after the discovery that vitamin C had no amine component.
Throughout the early 1900s, the use of deprivation studies allowed scientists to isolate and identify a number of vitamins. Initially, lipid from fish oil was used to cure rickets in rats, and the fat-soluble nutrient was called "antirachitic A". The irony here is that the first "vitamin" bioactivity ever isolated, which cured rickets, was initially called "vitamin A", the bioactivity of which is now called vitamin D. What we now call "vitamin A" was identified in fish oil because it was inactivated by ultraviolet light. In 1931, Albert Szent-Györgyi and a fellow researcher Joseph Svirbely determined that "hexuronic acid" was actually vitamin C and noted its anti-scorbutic activity. In 1937, Szent-Györgyi was awarded the Nobel Prize for his discovery. In 1943 Edward Adelbert Doisy and Henrik Dam were awarded the Nobel Prize for their discovery of vitamin K and its chemical structure.
# In humans
Vitamins are classified as either water-soluble, meaning that they dissolve easily in water or fat-soluble vitamins, which are absorbed through the intestinal tract with the help of lipids (fats). In general, water-soluble vitamins are readily excreted from the body. Each vitamin is typically used in multiple reactions and, therefore, most have multiple functions.
In humans there are 13 vitamins: 4 fat-soluble (A, D, E and K) and 9 water-soluble (8 B vitamins and vitamin C).
# In nutrition and diseases
Vitamins are essential for the normal growth and development of a multicellular organism. Using the genetic blueprint inherited from its parents, a fetus begins to develop, at the moment of conception, from the nutrients it absorbs. It requires certain vitamins and minerals to be present at certain times. These nutrients facilitate the chemical reactions that produce among other things, skin, bone, and muscle. If there is serious deficiency in one or more of these nutrients, a child may develop a deficiency disease. Even minor deficiencies may cause permanent damage.
For the most part, vitamins are obtained with food, but a few are obtained by other means. For example, microorganisms in the intestine—commonly known as "gut flora"—produce vitamin K and biotin, while one form of vitamin D is synthesized in the skin with the help of natural ultraviolet in sunlight. Humans can produce some vitamins from precursors they consume. Examples include vitamin A, produced from beta carotene, and niacin, from the amino acid tryptophan.
Once growth and development are completed, vitamins remain essential nutrients for the healthy maintenance of the cells, tissues, and organs that make up a multicellular organism; they also enable a multicellular life form to efficiently use chemical energy provided by food it eats, and to help process the proteins, carbohydrates, and fats required for respiration.
## Deficiencies
Deficiencies of vitamins are classified as either primary or secondary. A primary deficiency occurs when an organism does not get enough of the vitamin in its food. A secondary deficiency may be due to an underlying disorder that prevents or limits the absorption or use of the vitamin, due to a “lifestyle factor”, such as smoking, excessive alcohol consumption, or the use of medications that interfere with the absorption or use of the vitamin. People who eat a varied diet are unlikely to develop a severe primary vitamin deficiency. In contrast, restrictive diets have the potential to cause prolonged vitamin deficits, which may result in often painful and potentially deadly diseases.
Because human bodies do not store most vitamins, humans must consume them regularly to avoid deficiency. Human bodily stores for different vitamins vary widely; vitamins A, D, and B12 are stored in significant amounts in the human body, mainly in the liver, and an adult human's diet may be deficient in vitamins A and B12 for many months before developing a deficiency condition. Vitamin B3 is not stored in the human body in significant amounts, so stores may only last a couple of weeks.
Well-known human vitamin deficiencies involve thiamine (beriberi), niacin (pellagra), vitamin C (scurvy) and vitamin D (rickets). In much of the developed world, such deficiencies are rare; this is due to (1) an adequate supply of food; and (2) the addition of vitamins and minerals to common foods, often called fortification.
## Side effects and overdose
In large doses, some vitamins have documented side effects that tend to be more severe with a larger dosage. The likelihood of consuming too much of any vitamin from food is remote, but overdosing from vitamin supplementation does occur. At high enough dosages some vitamins cause side effects such as nausea, diarrhea, and vomiting. When side effects emerge, recovery is often accomplished by reducing the dosage. The concentrations of vitamins an individual can tolerate vary widely, and appear to be related to age and state of health. In the United States, overdose exposure to all formulations of vitamins was reported by 62,562 individuals in 2004 (nearly 80% of these exposures were in children under the age of 6), leading to 53 "major" life-threatening outcomes and 3 deaths—a small number in comparison to the 19,250 people who died of unintentional poisoning of all kinds in the U.S. in the same year (2004).
# Supplements
Dietary supplements, often containing vitamins, are used to ensure that adequate amounts of nutrients are obtained on a daily basis, if optimal amounts of the nutrients cannot be obtained through a varied diet. Scientific evidence supporting the benefits of some dietary supplements is well established for certain health conditions, but others need further study.
In the United States, advertising for dietary supplements is required to include a disclaimer that the product is not intended to treat, diagnose, mitigate, prevent, or cure disease, and that any health claims have not been evaluated by the Food and Drug Administration. In some cases, dietary supplements may have unwanted effects, especially if taken before surgery, with other dietary supplements or medicines, or if the person taking them has certain health conditions. Vitamin supplements may also contain levels of vitamins many times higher, and in different forms, than one may ingest through food.
Intake of excessive quantities can cause vitamin poisoning, most commonly for Vitamin A and Vitamin D. For this reason, most common vitamins have recommended upper daily intake amounts.
## Effectiveness
Multivitamins may cause a small reduction in the incidence of cancer in men. Multivitamins may not reduce cardiovascular disease in men.
## Governmental regulation of vitamin supplements
Most countries place dietary supplements in a special category under the general umbrella of foods, not drugs. This necessitates that the manufacturer, and not the government, be responsible for ensuring that its dietary supplement products are safe before they are marketed. Unlike drug products, that must explicitly be proven safe and effective for their intended use before marketing, there are often no provisions to "approve" dietary supplements for safety or effectiveness before they reach the consumer. Also unlike drug products, manufacturers and distributors of dietary supplements are not generally required to report any claims of injuries or illnesses that may be related to the use of their products.
# Names in current and previous nomenclatures
The reason the set of vitamins seems to skip directly from E to K is that the vitamins corresponding to "letters" F-J were either reclassified over time, discarded as false leads, or renamed because of their relationship to "vitamin B", which became a "complex" of vitamins.
The German-speaking scientists who isolated and described vitamin K (in addition to naming it as such) did so because the vitamin is intimately involved in the Koagulation of blood following wounding. At the time, most (but not all) of the letters from F through J were already designated, so the use of the letter K was considered quite reasonable.
The following table lists chemicals that had previously been classified as vitamins, as well as the earlier names of vitamins that later became part of the B-complex: | Vitamin
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [2]
# Overview
A vitamin is an organic compound required as a nutrient in tiny amounts by an organism.[1] A compound is called a vitamin when it cannot be synthesized in sufficient quantities by an organism, and must be obtained from the diet. Thus, the term is conditional both on the circumstances and the particular organism. For example, ascorbic acid functions as vitamin C for some animals but not others, and vitamins D and K are required in the human diet only in certain circumstances.[2] Vitamins are defined by their biological activity, not their structure. Thus, each "vitamin" actually refers to a number of vitamer compounds, which form a set of distinct chemical compounds that show the biological activity of a particular vitamin. Such a set of chemicals are grouped under an alphabetized vitamin "generic descriptor" title, such as "vitamin A," which (for example) includes retinal, retinol, and many carotenoids. [3] Vitamers are often inter-convertible in the body. The term vitamin does not include other essential nutrients such as dietary minerals, essential fatty acids, or essential amino acids, nor does it encompass the large number of other nutrients that promote health but that are not essential for life.
Vitamins have diverse biochemical functions, including function as hormones (e.g. vitamin D), antioxidants (e.g. vitamin E), and mediators of cell signaling and regulators of cell and tissue growth and differentiation (e.g. vitamin A) [4]. The largest number of vitamins (e.g. B complex vitamins) function as precursors for enzyme cofactor bio-molecules (coenzymes), that help act as catalysts and substrates in metabolism. When acting as part of a catalyst, vitamins are bound to enzymes and are called prosthetic groups. For example, biotin is part of enzymes involved in making fatty acids. Vitamins also act as coenzymes to carry chemical groups between enzymes. For example, folic acid carries various forms of carbon group – methyl, formyl and methylene - in the cell. Although these roles in assisting enzyme reactions are vitamins' best-known function, the other vitamin functions are equally important.[5]
Until the 1800s, vitamins were obtained solely through food intake, and changes in diet (which, for example, could occur during a particular growing season) can alter the types and amounts of vitamins ingested. Vitamins have been produced as commodity chemicals and made widely available as inexpensive pills for several decades,[6] allowing supplementation of the dietary intake.
# History
The value of eating certain foods to maintain health was recognized long before vitamins were identified. The ancient Egyptians knew that feeding a patient liver would help cure night blindness, an illness now known to be caused by a vitamin A deficiency. The advancement of ocean voyage during the Renaissance resulted in prolonged periods without access to fresh fruits and vegetables, and made illnesses from vitamin deficiency common among ship's crew.
In 1749, the Scottish surgeon James Lind discovered that citrus foods helped prevent scurvy, a particularly deadly disease in which collagen is not properly formed, causing poor wound healing, bleeding of the gums, severe pain, and death.[7] In 1753, Lind published his Treatise on the Scurvy, which recommended using lemons and limes to avoid scurvy, which was adopted by the British Royal Navy. This led to the nickname Limey for sailors of that organization. Lind's discovery, however, was not widely accepted by individuals in the Royal Navy's Arctic expeditions in the 19th century, where it was widely believed that scurvy could be prevented by practicing good hygiene, regular exercise, and by maintaining the morale of the crew while on board, rather than by a diet of fresh food.[7] As a result, Arctic expeditions continued to be plagued by scurvy and other deficiency diseases. In the early 20th century, when Robert Falcon Scott made his two expeditions to the Antarctic, the prevailing medical theory was that scurvy was caused by "tainted" canned food.[7]
In 1881, Russian surgeon Nikolai Lunin studied the effects of scurvy while at the University of Tartu in present-day Estonia.[8] He fed mice an artificial mixture of all the separate constituents of milk known at that time, namely the proteins, fats, carbohydrates, and salts. The mice that received only the individual constituents died, while the mice fed by milk itself developed normally. He made a conclusion that "a natural food such as milk must therefore contain, besides these known principal ingredients, small quantities of unknown substances essential to life".[8] However, his conclusions were rejected by other researchers when they were unable to reproduce his results. One difference was that he had used table sugar (sucrose), while other researchers had used milk sugar (lactose) that still contained small amounts of vitamin B.
In the Orient where polished white rice was the common staple food of the middle class, beriberi resulting from lack of vitamin B was endemic. In 1884, Takaki Kanehiro, a British trained medical doctor of the Japanese Navy observed that beriberi was endemic among low ranking crew who often ate nothing but rice but not among crews of Western navies and officers who were entitled to a Western-style diet. Kanehiro initially believed that lack of protein was the chief cause of beriberi. With the support of Japanese navy, he experimented using crews of two battleships, one crew was fed only white rice, while the other was fed a diet of meat, fish, barley, rice, and beans. The group that ate only white rice documented 161 crew with beriberi and 25 deaths, while the latter group had only 14 cases of beriberi and no deaths. This convinced Kanehiro and the Japanese Navy that diet was the cause of beriberi. This was confirmed in 1897, when Christiaan Eijkman discovered that feeding unpolished rice instead of the polished variety to chickens helped to prevent beriberi in the chickens. The following year, Frederick Hopkins postulated that some foods contained "accessory factors"—in addition to proteins, carbohydrates, fats, et cetera—that were necessary for the functions of the human body.[7] Hopkins was awarded the 1929 Nobel Prize for Physiology or Medicine with Christiaan Eijkman for their discovery of several vitamins.
In 1910, Japanese scientist Umetaro Suzuki succeeded in extracting a water-soluble complex of micronutrients from rice bran and named it aberic acid. He published this discovery in a Japanese scientific journal.[9]
When the article was translated into German, the translation failed to state that it was a newly discovered nutrient, a claim made in the original Japanese article, and hence his discovery failed to gain publicity. Polish biochemist Kazimierz Funk isolated the same complex of micronutrients and proposed the complex be named "Vitamine" (a portmanteau of "vital amine") in 1912.[10] The name soon became synonymous with Hopkins' "accessory factors", and by the time it was shown that not all vitamins were amines, the word was already ubiquitous. In 1920, Jack Cecil Drummond proposed that the final "e" be dropped to deemphasize the "amine" reference after the discovery that vitamin C had no amine component.
Throughout the early 1900s, the use of deprivation studies allowed scientists to isolate and identify a number of vitamins. Initially, lipid from fish oil was used to cure rickets in rats, and the fat-soluble nutrient was called "antirachitic A". The irony here is that the first "vitamin" bioactivity ever isolated, which cured rickets, was initially called "vitamin A", the bioactivity of which is now called vitamin D.[11] What we now call "vitamin A" was identified in fish oil because it was inactivated by ultraviolet light. In 1931, Albert Szent-Györgyi and a fellow researcher Joseph Svirbely determined that "hexuronic acid" was actually vitamin C and noted its anti-scorbutic activity. In 1937, Szent-Györgyi was awarded the Nobel Prize for his discovery. In 1943 Edward Adelbert Doisy and Henrik Dam were awarded the Nobel Prize for their discovery of vitamin K and its chemical structure.
# In humans
Vitamins are classified as either water-soluble, meaning that they dissolve easily in water or fat-soluble vitamins, which are absorbed through the intestinal tract with the help of lipids (fats). In general, water-soluble vitamins are readily excreted from the body. Each vitamin is typically used in multiple reactions and, therefore, most have multiple functions.[12]
In humans there are 13 vitamins: 4 fat-soluble (A, D, E and K) and 9 water-soluble (8 B vitamins and vitamin C).
# In nutrition and diseases
Vitamins are essential for the normal growth and development of a multicellular organism. Using the genetic blueprint inherited from its parents, a fetus begins to develop, at the moment of conception, from the nutrients it absorbs. It requires certain vitamins and minerals to be present at certain times. These nutrients facilitate the chemical reactions that produce among other things, skin, bone, and muscle. If there is serious deficiency in one or more of these nutrients, a child may develop a deficiency disease. Even minor deficiencies may cause permanent damage.[21]
For the most part, vitamins are obtained with food, but a few are obtained by other means. For example, microorganisms in the intestine—commonly known as "gut flora"—produce vitamin K and biotin, while one form of vitamin D is synthesized in the skin with the help of natural ultraviolet in sunlight. Humans can produce some vitamins from precursors they consume. Examples include vitamin A, produced from beta carotene, and niacin, from the amino acid tryptophan.[13]
Once growth and development are completed, vitamins remain essential nutrients for the healthy maintenance of the cells, tissues, and organs that make up a multicellular organism; they also enable a multicellular life form to efficiently use chemical energy provided by food it eats, and to help process the proteins, carbohydrates, and fats required for respiration.
## Deficiencies
Deficiencies of vitamins are classified as either primary or secondary. A primary deficiency occurs when an organism does not get enough of the vitamin in its food. A secondary deficiency may be due to an underlying disorder that prevents or limits the absorption or use of the vitamin, due to a “lifestyle factor”, such as smoking, excessive alcohol consumption, or the use of medications that interfere with the absorption or use of the vitamin.[20] People who eat a varied diet are unlikely to develop a severe primary vitamin deficiency. In contrast, restrictive diets have the potential to cause prolonged vitamin deficits, which may result in often painful and potentially deadly diseases.
Because human bodies do not store most vitamins, humans must consume them regularly to avoid deficiency. Human bodily stores for different vitamins vary widely; vitamins A, D, and B12 are stored in significant amounts in the human body, mainly in the liver,[20] and an adult human's diet may be deficient in vitamins A and B12 for many months before developing a deficiency condition. Vitamin B3 is not stored in the human body in significant amounts, so stores may only last a couple of weeks.[14][20]
Well-known human vitamin deficiencies involve thiamine (beriberi), niacin (pellagra), vitamin C (scurvy) and vitamin D (rickets). In much of the developed world, such deficiencies are rare; this is due to (1) an adequate supply of food; and (2) the addition of vitamins and minerals to common foods, often called fortification.[13][20]
## Side effects and overdose
In large doses, some vitamins have documented side effects that tend to be more severe with a larger dosage. The likelihood of consuming too much of any vitamin from food is remote, but overdosing from vitamin supplementation does occur. At high enough dosages some vitamins cause side effects such as nausea, diarrhea, and vomiting.[22][14] When side effects emerge, recovery is often accomplished by reducing the dosage. The concentrations of vitamins an individual can tolerate vary widely, and appear to be related to age and state of health.[23] In the United States, overdose exposure to all formulations of vitamins was reported by 62,562 individuals in 2004 (nearly 80% of these exposures were in children under the age of 6), leading to 53 "major" life-threatening outcomes and 3 deaths[24]—a small number in comparison to the 19,250 people who died of unintentional poisoning of all kinds in the U.S. in the same year (2004).[25]
# Supplements
Dietary supplements, often containing vitamins, are used to ensure that adequate amounts of nutrients are obtained on a daily basis, if optimal amounts of the nutrients cannot be obtained through a varied diet. Scientific evidence supporting the benefits of some dietary supplements is well established for certain health conditions, but others need further study.[26]
In the United States, advertising for dietary supplements is required to include a disclaimer that the product is not intended to treat, diagnose, mitigate, prevent, or cure disease, and that any health claims have not been evaluated by the Food and Drug Administration.[26] In some cases, dietary supplements may have unwanted effects, especially if taken before surgery, with other dietary supplements or medicines, or if the person taking them has certain health conditions.[26] Vitamin supplements may also contain levels of vitamins many times higher, and in different forms, than one may ingest through food.[27]
Intake of excessive quantities can cause vitamin poisoning, most commonly for Vitamin A and Vitamin D. For this reason, most common vitamins have recommended upper daily intake amounts.
## Effectiveness
Multivitamins may cause a small reduction in the incidence of cancer in men.[28] Multivitamins may not reduce cardiovascular disease in men.[29]
## Governmental regulation of vitamin supplements
Most countries place dietary supplements in a special category under the general umbrella of foods, not drugs. This necessitates that the manufacturer, and not the government, be responsible for ensuring that its dietary supplement products are safe before they are marketed. Unlike drug products, that must explicitly be proven safe and effective for their intended use before marketing, there are often no provisions to "approve" dietary supplements for safety or effectiveness before they reach the consumer. Also unlike drug products, manufacturers and distributors of dietary supplements are not generally required to report any claims of injuries or illnesses that may be related to the use of their products.[30] [31]
# Names in current and previous nomenclatures
The reason the set of vitamins seems to skip directly from E to K is that the vitamins corresponding to "letters" F-J were either reclassified over time, discarded as false leads, or renamed because of their relationship to "vitamin B", which became a "complex" of vitamins.
The German-speaking scientists who isolated and described vitamin K (in addition to naming it as such) did so because the vitamin is intimately involved in the Koagulation of blood following wounding. At the time, most (but not all) of the letters from F through J were already designated, so the use of the letter K was considered quite reasonable.
The following table lists chemicals that had previously been classified as vitamins, as well as the earlier names of vitamins that later became part of the B-complex: | https://www.wikidoc.org/index.php/Vitamin | |
5edfc7422a117164345a081c0606efee1f5cc778 | wikidoc | Volcano | Volcano
File:Volcano scheme.svg
# Overview
A volcano is an opening, or rupture, in a planet's surface or crust, which allows hot, molten rock, ash, and gases to escape from below the surface. Volcanic activity involving the extrusion of rock tends to form mountains or features like mountains over a period of time.
Volcanoes are generally found where tectonic plates are pulled apart or come together. A mid-oceanic ridge, for example the Mid-Atlantic Ridge, has examples of volcanoes caused by "divergent tectonic plates" pulling apart; the Pacific Ring of Fire has examples of volcanoes caused by "convergent tectonic plates" coming together. By contrast, volcanoes are usually not created where two tectonic plates slide past one another. Volcanoes can also form where there is stretching and thinning of the Earth's crust (called "non-hotspot intraplate volcanism"), such as in the African Rift Valley, the Wells Gray-Clearwater Volcanic Field and the Rio Grande Rift in North America and the European Rhine Graben with its Eifel volcanoes.
Volcanoes can be caused by "mantle plumes". These so-called "hotspots" , for example at Hawaii, can occur far from plate boundaries. Hotspot volcanoes are also found elsewhere in the solar system, especially on rocky planets and moons.
# Plate tectonics and hotspots
## Divergent plate boundaries
At the mid-oceanic ridges, two tectonic plates diverge from one another. New oceanic crust is being formed by hot molten rock slowly cooling and solidifying. The crust is very thin at mid-oceanic ridges due to the pull of the tectonic plates. The release of pressure due to the thinning of the crust leads to adiabatic expansion, and the partial melting of the mantle causing volcanism and creating new oceanic crust. Most divergent plate boundaries are at the bottom of the oceans, therefore most volcanic activity is submarine, forming new seafloor. Black smokers or deep sea vents are an example of this kind of volcanic activity. Where the mid-oceanic ridge is above sea-level, volcanic islands are formed, for example, Iceland.
## Convergent plate boundaries
Subduction zones are places where two plates, usually an oceanic plate and a continental plate, collide. In this case, the oceanic plate subducts, or submerges under the continental plate forming a deep ocean trench just offshore. Water released from the subducting plate lowers the melting temperature of the overlying mantle wedge, creating magma. This magma tends to be very viscous due to its high silica content, so often does not reach the surface and cools at depth. When it does reach the surface, a volcano is formed. Typical examples for this kind of volcano are Mount Etna and the volcanoes in the Pacific Ring of Fire.
## Hotspots
Hotspots are not usually located on the ridges of tectonic plates, but above mantle plumes, where the convection of the Earth's mantle creates a column of hot material that rises until it reaches the crust, which tends to be thinner than in other areas of the Earth. The temperature of the plume causes the crust to melt and form pipes, which can vent magma. Because the tectonic plates move whereas the mantle plume remains in the same place, each volcano becomes dormant after a while and a new volcano is then formed as the plate shifts over the hotspot. The Hawaiian Islands are thought to be formed in such a manner, as well as the Snake River Plain, with the Yellowstone Caldera being the part of the North American plate currently above the hotspot.
# Volcanic features
The most common perception of a volcano is of a conical mountain, spewing lava and poisonous gases from a crater at its summit. This describes just one of many types of volcano, and the features of volcanoes are much more complicated. The structure and behavior of volcanoes depends on a number of factors. Some volcanoes have rugged peaks formed by lava domes rather than a summit crater, whereas others present landscape features such as massive plateaus. Vents that issue volcanic material (lava, which is what magma is called once it has escaped to the surface, and ash) and gases (mainly steam and magmatic gases) can be located anywhere on the landform. Many of these vents give rise to smaller cones such as ] on a flank of Hawaii's Kīlauea.
Other types of volcano include cryovolcanoes (or ice volcanoes), particularly on some moons of Jupiter, Saturn and Neptune; and mud volcanoes, which are formations often not associated with known magmatic activity. Active mud volcanoes tend to involve temperatures much lower than those of igneous volcanoes, except when a mud volcano is actually a vent of an igneous volcano.
## Shield volcanoes
Shield volcanoes, so named for their broad, shield-like profiles, are formed by the eruption of low-viscosity lavas that can flow a great distance from a vent, but not generally explode catastrophically. The Hawaiian volcanic chain is a series of shield cones, and they are common in Iceland, as well.
## Lava domes
Lava domes are built by slow eruptions of highly viscous lavas. They are sometimes formed within the crater of a previous volcanic eruption (as in Mount Saint Helens), but can also form independently, as in the case of Lassen Peak. Like stratovolcanoes, they can produce violent, explosive eruptions, but their lavas generally do not flow far from the originating vent.
## Cinder cones
Volcanic cones or cinder cones result from eruptions that erupt mostly small pieces of scoria and pyroclastics (both resemble cinders, hence the name of this volcano type) that build up around the vent. These can be relatively short-lived eruptions that produce a cone-shaped hill perhaps 30 to 400 meters high. Most cinder cones erupt only once. Cinder cones may form as flank vents on larger volcanoes, or occur on their own. Parícutin in Mexico and Sunset Crater in Arizona are examples of cinder cones.
## Stratovolcanoes (composite volcano)
Stratovolcanoes are tall conical mountains composed of lava flows and other ejecta in alternate layers, the strata that give rise to the name. Stratovolcanoes are also known as composite volcanoes. Strato/composite volcanoes are made of cinders, ash and lava. The volcanoes are made by another volcano. Cinders and ash pile on top of each other, then lava flows on top and dries and then the process begins again. Classic examples include Mt. Fuji in Japan, Mount Mayon in the Philippines, and Mount Vesuvius and Stromboli in Italy. Within a relatively short geologic time scale stratovolcanoes are more dangerous (see stratovolcano for a list of dangers).
## Supervolcanoes
Supervolcano is the popular term for a large volcano that usually has a large caldera and can potentially produce devastation on an enormous, sometimes continental, scale. Such eruptions would be able to cause severe cooling of global temperatures for many years afterwards because of the huge volumes of sulfur and ash erupted. They are the most dangerous type of volcano. Examples include Yellowstone Caldera in Yellowstone National Park of western USA, Lake Taupo in New Zealand and Lake Toba in Sumatra, Indonesia. Supervolcanoes are hard to identify centuries later, given the enormous areas they cover. Large igneous provinces are also considered supervolcanoes because of the vast amount of basalt lava erupted, but they are non-explosive because only non-explosive eruptions such as Kilauea produce basalt lava.
## Submarine volcanoes
Submarine volcanoes are common features on the ocean floor. Some are active and, in shallow water, disclose their presence by blasting steam and rocky debris high above the surface of the sea. Many others lie at such great depths that the tremendous weight of the water above them prevents the explosive release of steam and gases, although they can be detected by hydrophones and discoloration of water because of volcanic gases. Pumice rafts may also appear. Even large submarine eruptions may not disturb the ocean surface. Because of the rapid cooling effect of water as compared to air, and increased buoyancy, submarine volcanoes often form rather steep pillars over their volcanic vents as compared to above-surface volcanoes. They may become so large that they break the ocean surface as new islands. Pillow lava is a common eruptive product of submarine volcanoes.
## Subglacial volcanoes
Subglacial volcanoes develop underneath icecaps. They are made up of flat lava flows atop extensive pillow lavas and palagonite. When the icecap melts, the lavas on the top collapse leaving a flat-topped mountain. Then, the pillow lavas also collapse, giving an angle of 37.5 degrees. These volcanoes are also called table mountains, tuyas or (uncommonly) mobergs. Very good examples of this type of volcano can be seen in Iceland, however, there are also tuyas in British Columbia. The origin of the term comes from Tuya Butte, which is one of the several tuyas in the area of the Tuya River and Tuya Range in northern British Columbia. Tuya Butte was the first such landform analyzed and so its name has entered the geological literature for this kind of volcanic formation. The Tuya Mountains Provincial Park was recently established to protect this unusual landscape, which lies north of Tuya Lake and south of the Jennings River near the boundary with the Yukon Territory.
### Antarctica eruption
In January, 2008, the British Antarctic Survey (Bas) scientists led by Hugh Corr and David Vaughan, reported (in the journal Nature Geoscience) that 2,200 years ago, a volcano erupted under Antarctica ice sheet (based on airborne survey with radar images). The biggest eruption in the last 10,000 years, the volcanic ash was found deposited on the ice surface under the Hudson Mountains, close to Pine Island Glacier.
# Erupted material
## Lava composition
Another way of classifying volcanoes is by the composition of material erupted (lava), since this affects the shape of the volcano. Lava can be broadly classified into 4 different compositions (Cas & Wright, 1987):
- If the erupted magma contains a high percentage (>63%) of silica, the lava is called felsic.
Felsic lavas (or rhyolites) tend to be highly viscous (not very fluid) and are erupted as domes or short, stubby flows. Viscous lavas tend to form stratovolcanoes or lava domes. Lassen Peak in California is an example of a volcano formed from felsic lava and is actually a large lava dome.
Because siliceous magmas are so viscous, they tend to trap volatiles (gases) that are present, which cause the magma to erupt catastrophically, eventually forming stratovolcanoes. Pyroclastic flows (ignimbrites) are highly hazardous products of such volcanoes, since they are composed of molten volcanic ash too heavy to go up into the atmosphere, so they hug the volcano's slopes and travel far from their vents during large eruptions. Temperatures as high as 1,200 °C are known to occur in pyroclastic flows, which will incinerate everything flammable in their path and thick layers of hot pyroclastic flow deposits can be laid down, often up to many meters thick. Alaska's Valley of Ten Thousand Smokes, formed by the eruption of Novarupta near Katmai in 1912, is an example of a thick pyroclastic flow or ignimbrite deposit. Volcanic ash that is light enough to be erupted high into the Earth's atmosphere may travel many kilometres before it falls back to ground as a tuff.
- Felsic lavas (or rhyolites) tend to be highly viscous (not very fluid) and are erupted as domes or short, stubby flows. Viscous lavas tend to form stratovolcanoes or lava domes. Lassen Peak in California is an example of a volcano formed from felsic lava and is actually a large lava dome.
- Because siliceous magmas are so viscous, they tend to trap volatiles (gases) that are present, which cause the magma to erupt catastrophically, eventually forming stratovolcanoes. Pyroclastic flows (ignimbrites) are highly hazardous products of such volcanoes, since they are composed of molten volcanic ash too heavy to go up into the atmosphere, so they hug the volcano's slopes and travel far from their vents during large eruptions. Temperatures as high as 1,200 °C are known to occur in pyroclastic flows, which will incinerate everything flammable in their path and thick layers of hot pyroclastic flow deposits can be laid down, often up to many meters thick. Alaska's Valley of Ten Thousand Smokes, formed by the eruption of Novarupta near Katmai in 1912, is an example of a thick pyroclastic flow or ignimbrite deposit. Volcanic ash that is light enough to be erupted high into the Earth's atmosphere may travel many kilometres before it falls back to ground as a tuff.
- If the erupted magma contains 52–63% silica, the lava is of intermediate composition.
These "andesitic" volcanoes generally only occur above subduction zones (e.g. Mount Merapi in Indonesia).
- These "andesitic" volcanoes generally only occur above subduction zones (e.g. Mount Merapi in Indonesia).
- If the erupted magma contains 45% silica, the lava is called mafic (because it contains higher percentages of magnesium (Mg) and iron (Fe)) or basaltic. These lavas are usually much less viscous than rhyolitic lavas, depending on their eruption temperature; they also tend to be hotter than felsic lavas. Mafic lavas occur in a wide range of settings:
At mid-ocean ridges, where two oceanic plates are pulling apart, basaltic lava erupts as pillows to fill the gap;
Shield volcanoes (e.g. the Hawaiian Islands, including Mauna Loa and Kilauea), on both oceanic and continental crust;
As continental flood basalts.
- At mid-ocean ridges, where two oceanic plates are pulling apart, basaltic lava erupts as pillows to fill the gap;
- Shield volcanoes (e.g. the Hawaiian Islands, including Mauna Loa and Kilauea), on both oceanic and continental crust;
- As continental flood basalts.
- Some erupted magmas contain <=45% silica and produce ultramafic lava. Ultramafic flows, also known as komatiites, are very rare; indeed, very few have been erupted at the Earth's surface since the Proterozoic, when the planet's heat flow was higher. They are (or were) the hottest lavas, and probably more fluid than common mafic lavas.
## Lava texture
Two types of lava are named according to the surface texture: Template:OkinaATemplate:Okinaa (Template:Pronounced) and pāhoehoe (pronounced Template:IPA2), both words having Hawaiian origins. Template:OkinaATemplate:Okinaa is characterized by a rough, clinkery surface and is what most viscous and hot lava flows look like. However, even basaltic or mafic flows can be erupted as Template:OkinaaTemplate:Okinaa flows, particularly if the eruption rate is high and the slope is steep. Pāhoehoe is characterized by its smooth and often ropey or wrinkly surface and is generally formed from more fluid lava flows. Usually, only mafic flows will erupt as pāhoehoe, since they often erupt at higher temperatures or have the proper chemical make-up to allow them to flow at a higher fluidity.
# Volcanic activity
A popular way of classifying magmatic volcanoes is by their frequency of eruption, with those that erupt regularly called active, those that have erupted in historical times but are now quiet called dormant, and those that have not erupted in historical times called extinct. However, these popular classifications—extinct in particular—are practically meaningless to scientists. They use classifications which refer to a particular volcano's formative and eruptive processes and resulting shapes, which was explained above.
There is no real consensus among volcanologists on how to define an "active" volcano. The lifespan of a volcano can vary from months to several million years, making such a distinction sometimes meaningless when compared to the lifespans of humans or even civilizations. For example, many of Earth's volcanoes have erupted dozens of times in the past few thousand years but are not currently showing signs of eruption. Given the long lifespan of such volcanoes, they are very active. By human lifespans, however, they are not.
Scientists usually consider a volcano to be active if it is currently erupting or showing signs of unrest, such as unusual earthquake activity or significant new gas emissions. Many scientists also consider a volcano active if it has erupted in historic time. It is important to note that the span of recorded history differs from region to region; in the Mediterranean, recorded history reaches back more than 3,000 years but in the Pacific Northwest of the United States, it reaches back less than 300 years, and in Hawaii, little more than 200 years. The Smithsonian Global Volcanism Program's definition of 'active' is having erupted within the last 10,000 years.
Dormant volcanoes are those that are not currently active (as defined above), but could become restless or erupt again. Confusion however, can arise because many volcanoes which scientists consider to be active are referred to as dormant by laypersons or in the media.
Extinct volcanoes are those that scientists consider unlikely to erupt again, because the volcano no longer has a lava supply anymore. Examples of extinct volcanoes are many volcanoes on the Hawaiian Islands in the U.S. (extinct because the Hawaii hotspot is centered near the Big Island), and Paricutin, which is monogenetic. Otherwise, whether a volcano is truly extinct is often difficult to determine. Since "supervolcano" calderas can have eruptive lifespans sometimes measured in millions of years, a caldera that has not produced an eruption in tens of thousands of years is likely to be considered dormant instead of extinct. For example, the Yellowstone Caldera in Yellowstone National Park is at least 2 million years old and hasn't erupted violently for approximately 640,000 years, although there has been some minor activity relatively recently, with hydrothermal eruptions less than 10,000 years ago and lava flows about 70,000 years ago. For this reason, scientists do not consider the Yellowstone Caldera extinct. In fact, because the caldera has frequent earthquakes, a very active geothermal system (i.e. the entirety of the geothermal activity found in Yellowstone National Park), and rapid rates of ground uplift, many scientists consider it to be an active volcano.
# Notable volcanoes
The 16 current Decade Volcanoes are:
# Effects of volcanoes
There are many different kinds of volcanic activity and eruptions: phreatic eruptions (steam-generated eruptions), explosive eruption of high-silica lava (e.g., rhyolite), effusive eruption of low-silica lava (e.g., basalt), pyroclastic flows, lahars (debris flow) and carbon dioxide emission. All of these activities can pose a hazard to humans. Earthquakes, hot springs, fumaroles, mud pots and geysers often accompany volcanic activity.
The concentrations of different volcanic gases can vary considerably from one volcano to the next. Water vapor is typically the most abundant volcanic gas, followed by carbon dioxide and sulfur dioxide. Other principal volcanic gases include hydrogen sulfide, hydrogen chloride, and hydrogen fluoride. A large number of minor and trace gases are also found in volcanic emissions, for example hydrogen, carbon monoxide, halocarbons, organic compounds, and volatile metal chlorides.
Large, explosive volcanic eruptions inject water vapor (H2O), carbon dioxide (CO2), sulfur dioxide (SO2), hydrogen chloride (HCl), hydrogen fluoride (HF) and ash (pulverized rock and pumice) into the stratosphere to heights of 16–32 kilometres (10–20 mi) above the Earth's surface. The most significant impacts from these injections come from the conversion of sulfur dioxide to sulfuric acid (H2SO4), which condenses rapidly in the stratosphere to form fine sulfate aerosols. The aerosols increase the Earth's albedo—its reflection of radiation from the Sun back into space - and thus cool the Earth's lower atmosphere or troposphere; however, they also absorb heat radiated up from the Earth, thereby warming the stratosphere. Several eruptions during the past century have caused a decline in the average temperature at the Earth's surface of up to half a degree (Fahrenheit scale) for periods of one to three years. The sulfate aerosols also promote complex chemical reactions on their surfaces that alter chlorine and nitrogen chemical species in the stratosphere. This effect, together with increased stratospheric chlorine levels from chlorofluorocarbon pollution, generates chlorine monoxide (ClO), which destroys ozone (O3). As the aerosols grow and coagulate, they settle down into the upper troposphere where they serve as nuclei for cirrus clouds and further modify the Earth's radiation balance. Most of the hydrogen chloride (HCl) and hydrogen fluoride (HF) are dissolved in water droplets in the eruption cloud and quickly fall to the ground as acid rain. The injected ash also falls rapidly from the stratosphere; most of it is removed within several days to a few weeks. Finally, explosive volcanic eruptions release the greenhouse gas carbon dioxide and thus provide a deep source of carbon for biogeochemical cycles.
Gas emissions from volcanoes are a natural contributor to acid rain. Volcanic activity releases about 130 to 230 teragrams (145 million to 255 million short tons) of carbon dioxide each year. Volcanic eruptions may inject aerosols into the Earth's atmosphere. Large injections may cause visual effects such as unusually colorful sunsets and affect global climate mainly by cooling it. Volcanic eruptions also provide the benefit of adding nutrients to soil through the weathering process of volcanic rocks. These fertile soils assist the growth of plants and various crops. Volcanic eruptions can also create new islands, as the magma cools and solidifies upon contact with the water.
# Volcanoes on other planetary bodies
The Earth's Moon has no large volcanoes and no current volcanic activity, although recent evidence suggests it may still possess a partially molten core. However, the Moon does have many volcanic features such as maria (the darker patches seen on the moon), rilles and domes.
The planet Venus has a surface that is 90% basalt, indicating that volcanism played a major role in shaping its surface. The planet may have had a major global resurfacing event about 500 million years ago, from what scientists can tell from the density of impact craters on the surface. Lava flows are widespread and forms of volcanism not present on Earth occur as well. Changes in the planet's atmosphere and observations of lightning, have been attributed to ongoing volcanic eruptions, although there is no confirmation of whether or not Venus is still volcanically active. However, radar sounding by the Magellan probe revealed evidence for comparatively recent volcanic activity at Venus's highest volcano Maat Mons, in the form of ash flows near the summit and on the northern flank.
There are several extinct volcanoes on Mars, four of which are vast shield volcanoes far bigger than any on Earth. They include Arsia Mons, Ascraeus Mons, Hecates Tholus, Olympus Mons, and Pavonis Mons. These volcanoes have been extinct for many millions of years, but the European Mars Express spacecraft has found evidence that volcanic activity may have occurred on Mars in the recent past as well.
Jupiter's moon Io is the most volcanically active object in the solar system because of tidal interaction with Jupiter. It is covered with volcanoes that erupt sulfur, sulfur dioxide and silicate rock, and as a result, Io is constantly being resurfaced. Its lavas are the hottest known anywhere in the solar system, with temperatures exceeding 1,800 K (1,500 °C). In February 2001, the largest recorded volcanic eruptions in the solar system occurred on Io. Europa, the smallest of Jupiter's Galilean moons, also appears to have an active volcanic system, except that its volcanic activity is entirely in the form of water, which freezes into ice on the frigid surface. This process is known as cryovolcanism, and is apparently most common on the moons of the outer planets of the solar system.
In 1989 the Voyager 2 spacecraft observed cryovolcanoes (ice volcanoes) on Triton, a moon of Neptune, and in 2005 the Cassini-Huygens probe photographed fountains of frozen particles erupting from Enceladus, a moon of Saturn. The ejecta may be composed of water, liquid nitrogen, dust, or methane compounds. Cassini-Huygens also found evidence of a methane-spewing cryovolcano on the Saturnian moon Titan, which is believed to be a significant source of the methane found in its atmosphere. It is theorized that cryovolcanism may also be present on the Kuiper Belt Object Quaoar.
# Etymology
Volcano is thought to derive from Vulcano, a volcanic island in the Aeolian Islands of Italy whose name in turn originates from Vulcan, the name of a god of fire in Roman mythology. The study of volcanoes is called volcanology, sometimes spelled vulcanology.
The Roman name for the island Vulcano has contributed the word for volcano in most modern European languages.
# In culture
## Past beliefs
Many ancient accounts ascribe volcanic eruptions to supernatural causes, such as the actions of gods or demigods. To the ancient Greeks, volcanoes' capricious power could only be explained as acts of the gods, while 16th/17th-century German astronomer Johannes Kepler believed they were ducts for the Earth's tears. One early idea counter to this was proposed by Jesuit Athanasius Kircher (1602–1680), who witnessed eruptions of Mount Etna and Stromboli, then visited the crater of Vesuvius and published his view of an Earth with a central fire connected to numerous others caused by the burning of sulfur, bitumen and coal.
Various explanations were proposed for volcano behavior before the modern understanding of the Earth's mantle structure as a semisolid material was developed. For decades after awareness that compression and radioactive materials may be heat sources, their contributions were specifically discounted. Volcanic action was often attributed to chemical reactions and a thin layer of molten rock near the surface.
## Heraldry
Volcanoes appear as a charge in heraldry.
# Panoramas | Volcano
File:Volcano scheme.svg
# Overview
A volcano is an opening, or rupture, in a planet's surface or crust, which allows hot, molten rock, ash, and gases to escape from below the surface. Volcanic activity involving the extrusion of rock tends to form mountains or features like mountains over a period of time.
Volcanoes are generally found where tectonic plates are pulled apart or come together. A mid-oceanic ridge, for example the Mid-Atlantic Ridge, has examples of volcanoes caused by "divergent tectonic plates" pulling apart; the Pacific Ring of Fire has examples of volcanoes caused by "convergent tectonic plates" coming together. By contrast, volcanoes are usually not created where two tectonic plates slide past one another. Volcanoes can also form where there is stretching and thinning of the Earth's crust (called "non-hotspot intraplate volcanism"), such as in the African Rift Valley, the Wells Gray-Clearwater Volcanic Field and the Rio Grande Rift in North America and the European Rhine Graben with its Eifel volcanoes.
Volcanoes can be caused by "mantle plumes". These so-called "hotspots" , for example at Hawaii, can occur far from plate boundaries. Hotspot volcanoes are also found elsewhere in the solar system, especially on rocky planets and moons.
# Plate tectonics and hotspots
## Divergent plate boundaries
At the mid-oceanic ridges, two tectonic plates diverge from one another. New oceanic crust is being formed by hot molten rock slowly cooling and solidifying. The crust is very thin at mid-oceanic ridges due to the pull of the tectonic plates. The release of pressure due to the thinning of the crust leads to adiabatic expansion, and the partial melting of the mantle causing volcanism and creating new oceanic crust. Most divergent plate boundaries are at the bottom of the oceans, therefore most volcanic activity is submarine, forming new seafloor. Black smokers or deep sea vents are an example of this kind of volcanic activity. Where the mid-oceanic ridge is above sea-level, volcanic islands are formed, for example, Iceland.
## Convergent plate boundaries
Subduction zones are places where two plates, usually an oceanic plate and a continental plate, collide. In this case, the oceanic plate subducts, or submerges under the continental plate forming a deep ocean trench just offshore. Water released from the subducting plate lowers the melting temperature of the overlying mantle wedge, creating magma. This magma tends to be very viscous due to its high silica content, so often does not reach the surface and cools at depth. When it does reach the surface, a volcano is formed. Typical examples for this kind of volcano are Mount Etna and the volcanoes in the Pacific Ring of Fire.
## Hotspots
Hotspots are not usually located on the ridges of tectonic plates, but above mantle plumes, where the convection of the Earth's mantle creates a column of hot material that rises until it reaches the crust, which tends to be thinner than in other areas of the Earth. The temperature of the plume causes the crust to melt and form pipes, which can vent magma. Because the tectonic plates move whereas the mantle plume remains in the same place, each volcano becomes dormant after a while and a new volcano is then formed as the plate shifts over the hotspot. The Hawaiian Islands are thought to be formed in such a manner, as well as the Snake River Plain, with the Yellowstone Caldera being the part of the North American plate currently above the hotspot.
# Volcanic features
The most common perception of a volcano is of a conical mountain, spewing lava and poisonous gases from a crater at its summit. This describes just one of many types of volcano, and the features of volcanoes are much more complicated. The structure and behavior of volcanoes depends on a number of factors. Some volcanoes have rugged peaks formed by lava domes rather than a summit crater, whereas others present landscape features such as massive plateaus. Vents that issue volcanic material (lava, which is what magma is called once it has escaped to the surface, and ash) and gases (mainly steam and magmatic gases) can be located anywhere on the landform. Many of these vents give rise to smaller cones such as [[Pu'u 'Ō'ō|PuTemplate:Okinau Template:OkinaŌTemplate:Okinaō]] on a flank of Hawaii's Kīlauea.
Other types of volcano include cryovolcanoes (or ice volcanoes), particularly on some moons of Jupiter, Saturn and Neptune; and mud volcanoes, which are formations often not associated with known magmatic activity. Active mud volcanoes tend to involve temperatures much lower than those of igneous volcanoes, except when a mud volcano is actually a vent of an igneous volcano.
## Shield volcanoes
Shield volcanoes, so named for their broad, shield-like profiles, are formed by the eruption of low-viscosity lavas that can flow a great distance from a vent, but not generally explode catastrophically. The Hawaiian volcanic chain is a series of shield cones, and they are common in Iceland, as well.
## Lava domes
Lava domes are built by slow eruptions of highly viscous lavas. They are sometimes formed within the crater of a previous volcanic eruption (as in Mount Saint Helens), but can also form independently, as in the case of Lassen Peak. Like stratovolcanoes, they can produce violent, explosive eruptions, but their lavas generally do not flow far from the originating vent.
## Cinder cones
Volcanic cones or cinder cones result from eruptions that erupt mostly small pieces of scoria and pyroclastics (both resemble cinders, hence the name of this volcano type) that build up around the vent. These can be relatively short-lived eruptions that produce a cone-shaped hill perhaps 30 to 400 meters high. Most cinder cones erupt only once. Cinder cones may form as flank vents on larger volcanoes, or occur on their own. Parícutin in Mexico and Sunset Crater in Arizona are examples of cinder cones.
## Stratovolcanoes (composite volcano)
Stratovolcanoes are tall conical mountains composed of lava flows and other ejecta in alternate layers, the strata that give rise to the name. Stratovolcanoes are also known as composite volcanoes. Strato/composite volcanoes are made of cinders, ash and lava. The volcanoes are made by another volcano. Cinders and ash pile on top of each other, then lava flows on top and dries and then the process begins again. Classic examples include Mt. Fuji in Japan, Mount Mayon in the Philippines, and Mount Vesuvius and Stromboli in Italy. Within a relatively short geologic time scale stratovolcanoes are more dangerous (see stratovolcano for a list of dangers).
## Supervolcanoes
Supervolcano is the popular term for a large volcano that usually has a large caldera and can potentially produce devastation on an enormous, sometimes continental, scale. Such eruptions would be able to cause severe cooling of global temperatures for many years afterwards because of the huge volumes of sulfur and ash erupted. They are the most dangerous type of volcano. Examples include Yellowstone Caldera in Yellowstone National Park of western USA, Lake Taupo in New Zealand and Lake Toba in Sumatra, Indonesia. Supervolcanoes are hard to identify centuries later, given the enormous areas they cover. Large igneous provinces are also considered supervolcanoes because of the vast amount of basalt lava erupted, but they are non-explosive because only non-explosive eruptions such as Kilauea produce basalt lava.
## Submarine volcanoes
Submarine volcanoes are common features on the ocean floor. Some are active and, in shallow water, disclose their presence by blasting steam and rocky debris high above the surface of the sea. Many others lie at such great depths that the tremendous weight of the water above them prevents the explosive release of steam and gases, although they can be detected by hydrophones and discoloration of water because of volcanic gases. Pumice rafts may also appear. Even large submarine eruptions may not disturb the ocean surface. Because of the rapid cooling effect of water as compared to air, and increased buoyancy, submarine volcanoes often form rather steep pillars over their volcanic vents as compared to above-surface volcanoes. They may become so large that they break the ocean surface as new islands. Pillow lava is a common eruptive product of submarine volcanoes.
## Subglacial volcanoes
Subglacial volcanoes develop underneath icecaps. They are made up of flat lava flows atop extensive pillow lavas and palagonite. When the icecap melts, the lavas on the top collapse leaving a flat-topped mountain. Then, the pillow lavas also collapse, giving an angle of 37.5 degrees[citation needed]. These volcanoes are also called table mountains, tuyas or (uncommonly) mobergs. Very good examples of this type of volcano can be seen in Iceland, however, there are also tuyas in British Columbia. The origin of the term comes from Tuya Butte, which is one of the several tuyas in the area of the Tuya River and Tuya Range in northern British Columbia. Tuya Butte was the first such landform analyzed and so its name has entered the geological literature for this kind of volcanic formation. The Tuya Mountains Provincial Park was recently established to protect this unusual landscape, which lies north of Tuya Lake and south of the Jennings River near the boundary with the Yukon Territory.
### Antarctica eruption
In January, 2008, the British Antarctic Survey (Bas) scientists led by Hugh Corr and David Vaughan, reported (in the journal Nature Geoscience) that 2,200 years ago, a volcano erupted under Antarctica ice sheet (based on airborne survey with radar images). The biggest eruption in the last 10,000 years, the volcanic ash was found deposited on the ice surface under the Hudson Mountains, close to Pine Island Glacier.[1]
# Erupted material
## Lava composition
Another way of classifying volcanoes is by the composition of material erupted (lava), since this affects the shape of the volcano. Lava can be broadly classified into 4 different compositions (Cas & Wright, 1987):
- If the erupted magma contains a high percentage (>63%) of silica, the lava is called felsic.
Felsic lavas (or rhyolites) tend to be highly viscous (not very fluid) and are erupted as domes or short, stubby flows. Viscous lavas tend to form stratovolcanoes or lava domes. Lassen Peak in California is an example of a volcano formed from felsic lava and is actually a large lava dome.
Because siliceous magmas are so viscous, they tend to trap volatiles (gases) that are present, which cause the magma to erupt catastrophically, eventually forming stratovolcanoes. Pyroclastic flows (ignimbrites) are highly hazardous products of such volcanoes, since they are composed of molten volcanic ash too heavy to go up into the atmosphere, so they hug the volcano's slopes and travel far from their vents during large eruptions. Temperatures as high as 1,200 °C are known to occur in pyroclastic flows, which will incinerate everything flammable in their path and thick layers of hot pyroclastic flow deposits can be laid down, often up to many meters thick. Alaska's Valley of Ten Thousand Smokes, formed by the eruption of Novarupta near Katmai in 1912, is an example of a thick pyroclastic flow or ignimbrite deposit. Volcanic ash that is light enough to be erupted high into the Earth's atmosphere may travel many kilometres before it falls back to ground as a tuff.
- Felsic lavas (or rhyolites) tend to be highly viscous (not very fluid) and are erupted as domes or short, stubby flows. Viscous lavas tend to form stratovolcanoes or lava domes. Lassen Peak in California is an example of a volcano formed from felsic lava and is actually a large lava dome.
- Because siliceous magmas are so viscous, they tend to trap volatiles (gases) that are present, which cause the magma to erupt catastrophically, eventually forming stratovolcanoes. Pyroclastic flows (ignimbrites) are highly hazardous products of such volcanoes, since they are composed of molten volcanic ash too heavy to go up into the atmosphere, so they hug the volcano's slopes and travel far from their vents during large eruptions. Temperatures as high as 1,200 °C are known to occur in pyroclastic flows, which will incinerate everything flammable in their path and thick layers of hot pyroclastic flow deposits can be laid down, often up to many meters thick. Alaska's Valley of Ten Thousand Smokes, formed by the eruption of Novarupta near Katmai in 1912, is an example of a thick pyroclastic flow or ignimbrite deposit. Volcanic ash that is light enough to be erupted high into the Earth's atmosphere may travel many kilometres before it falls back to ground as a tuff.
- If the erupted magma contains 52–63% silica, the lava is of intermediate composition.
These "andesitic" volcanoes generally only occur above subduction zones (e.g. Mount Merapi in Indonesia).
- These "andesitic" volcanoes generally only occur above subduction zones (e.g. Mount Merapi in Indonesia).
- If the erupted magma contains <52% and >45% silica, the lava is called mafic (because it contains higher percentages of magnesium (Mg) and iron (Fe)) or basaltic. These lavas are usually much less viscous than rhyolitic lavas, depending on their eruption temperature; they also tend to be hotter than felsic lavas. Mafic lavas occur in a wide range of settings:
At mid-ocean ridges, where two oceanic plates are pulling apart, basaltic lava erupts as pillows to fill the gap;
Shield volcanoes (e.g. the Hawaiian Islands, including Mauna Loa and Kilauea), on both oceanic and continental crust;
As continental flood basalts.
- At mid-ocean ridges, where two oceanic plates are pulling apart, basaltic lava erupts as pillows to fill the gap;
- Shield volcanoes (e.g. the Hawaiian Islands, including Mauna Loa and Kilauea), on both oceanic and continental crust;
- As continental flood basalts.
- Some erupted magmas contain <=45% silica and produce ultramafic lava. Ultramafic flows, also known as komatiites, are very rare; indeed, very few have been erupted at the Earth's surface since the Proterozoic, when the planet's heat flow was higher. They are (or were) the hottest lavas, and probably more fluid than common mafic lavas.
## Lava texture
Two types of lava are named according to the surface texture: Template:OkinaATemplate:Okinaa (Template:Pronounced) and pāhoehoe (pronounced Template:IPA2), both words having Hawaiian origins. Template:OkinaATemplate:Okinaa is characterized by a rough, clinkery surface and is what most viscous and hot lava flows look like. However, even basaltic or mafic flows can be erupted as Template:OkinaaTemplate:Okinaa flows, particularly if the eruption rate is high and the slope is steep. Pāhoehoe is characterized by its smooth and often ropey or wrinkly surface and is generally formed from more fluid lava flows. Usually, only mafic flows will erupt as pāhoehoe, since they often erupt at higher temperatures or have the proper chemical make-up to allow them to flow at a higher fluidity.
# Volcanic activity
A popular way of classifying magmatic volcanoes is by their frequency of eruption, with those that erupt regularly called active, those that have erupted in historical times but are now quiet called dormant, and those that have not erupted in historical times called extinct. However, these popular classifications—extinct in particular—are practically meaningless to scientists. They use classifications which refer to a particular volcano's formative and eruptive processes and resulting shapes, which was explained above.
There is no real consensus among volcanologists on how to define an "active" volcano. The lifespan of a volcano can vary from months to several million years, making such a distinction sometimes meaningless when compared to the lifespans of humans or even civilizations. For example, many of Earth's volcanoes have erupted dozens of times in the past few thousand years but are not currently showing signs of eruption. Given the long lifespan of such volcanoes, they are very active. By human lifespans, however, they are not.
Scientists usually consider a volcano to be active if it is currently erupting or showing signs of unrest, such as unusual earthquake activity or significant new gas emissions. Many scientists also consider a volcano active if it has erupted in historic time. It is important to note that the span of recorded history differs from region to region; in the Mediterranean, recorded history reaches back more than 3,000 years but in the Pacific Northwest of the United States, it reaches back less than 300 years, and in Hawaii, little more than 200 years. The Smithsonian Global Volcanism Program's definition of 'active' is having erupted within the last 10,000 years.
Dormant volcanoes are those that are not currently active (as defined above), but could become restless or erupt again. Confusion however, can arise because many volcanoes which scientists consider to be active are referred to as dormant by laypersons or in the media.
Extinct volcanoes are those that scientists consider unlikely to erupt again, because the volcano no longer has a lava supply anymore. Examples of extinct volcanoes are many volcanoes on the Hawaiian Islands in the U.S. (extinct because the Hawaii hotspot is centered near the Big Island), and Paricutin, which is monogenetic. Otherwise, whether a volcano is truly extinct is often difficult to determine. Since "supervolcano" calderas can have eruptive lifespans sometimes measured in millions of years, a caldera that has not produced an eruption in tens of thousands of years is likely to be considered dormant instead of extinct. For example, the Yellowstone Caldera in Yellowstone National Park is at least 2 million years old and hasn't erupted violently for approximately 640,000 years, although there has been some minor activity relatively recently, with hydrothermal eruptions less than 10,000 years ago and lava flows about 70,000 years ago. For this reason, scientists do not consider the Yellowstone Caldera extinct. In fact, because the caldera has frequent earthquakes, a very active geothermal system (i.e. the entirety of the geothermal activity found in Yellowstone National Park), and rapid rates of ground uplift, many scientists consider it to be an active volcano.
# Notable volcanoes
The 16 current Decade Volcanoes are:
# Effects of volcanoes
There are many different kinds of volcanic activity and eruptions: phreatic eruptions (steam-generated eruptions), explosive eruption of high-silica lava (e.g., rhyolite), effusive eruption of low-silica lava (e.g., basalt), pyroclastic flows, lahars (debris flow) and carbon dioxide emission. All of these activities can pose a hazard to humans. Earthquakes, hot springs, fumaroles, mud pots and geysers often accompany volcanic activity.
The concentrations of different volcanic gases can vary considerably from one volcano to the next. Water vapor is typically the most abundant volcanic gas, followed by carbon dioxide and sulfur dioxide. Other principal volcanic gases include hydrogen sulfide, hydrogen chloride, and hydrogen fluoride. A large number of minor and trace gases are also found in volcanic emissions, for example hydrogen, carbon monoxide, halocarbons, organic compounds, and volatile metal chlorides.
Large, explosive volcanic eruptions inject water vapor (H2O), carbon dioxide (CO2), sulfur dioxide (SO2), hydrogen chloride (HCl), hydrogen fluoride (HF) and ash (pulverized rock and pumice) into the stratosphere to heights of 16–32 kilometres (10–20 mi) above the Earth's surface. The most significant impacts from these injections come from the conversion of sulfur dioxide to sulfuric acid (H2SO4), which condenses rapidly in the stratosphere to form fine sulfate aerosols. The aerosols increase the Earth's albedo—its reflection of radiation from the Sun back into space - and thus cool the Earth's lower atmosphere or troposphere; however, they also absorb heat radiated up from the Earth, thereby warming the stratosphere. Several eruptions during the past century have caused a decline in the average temperature at the Earth's surface of up to half a degree (Fahrenheit scale) for periods of one to three years. The sulfate aerosols also promote complex chemical reactions on their surfaces that alter chlorine and nitrogen chemical species in the stratosphere. This effect, together with increased stratospheric chlorine levels from chlorofluorocarbon pollution, generates chlorine monoxide (ClO), which destroys ozone (O3). As the aerosols grow and coagulate, they settle down into the upper troposphere where they serve as nuclei for cirrus clouds and further modify the Earth's radiation balance. Most of the hydrogen chloride (HCl) and hydrogen fluoride (HF) are dissolved in water droplets in the eruption cloud and quickly fall to the ground as acid rain. The injected ash also falls rapidly from the stratosphere; most of it is removed within several days to a few weeks. Finally, explosive volcanic eruptions release the greenhouse gas carbon dioxide and thus provide a deep source of carbon for biogeochemical cycles.
Gas emissions from volcanoes are a natural contributor to acid rain. Volcanic activity releases about 130 to 230 teragrams (145 million to 255 million short tons) of carbon dioxide each year.[2] Volcanic eruptions may inject aerosols into the Earth's atmosphere. Large injections may cause visual effects such as unusually colorful sunsets and affect global climate mainly by cooling it. Volcanic eruptions also provide the benefit of adding nutrients to soil through the weathering process of volcanic rocks. These fertile soils assist the growth of plants and various crops. Volcanic eruptions can also create new islands, as the magma cools and solidifies upon contact with the water.
# Volcanoes on other planetary bodies
The Earth's Moon has no large volcanoes and no current volcanic activity, although recent evidence suggests it may still possess a partially molten core.[3] However, the Moon does have many volcanic features such as maria (the darker patches seen on the moon), rilles and domes.
The planet Venus has a surface that is 90% basalt, indicating that volcanism played a major role in shaping its surface. The planet may have had a major global resurfacing event about 500 million years ago,[4] from what scientists can tell from the density of impact craters on the surface. Lava flows are widespread and forms of volcanism not present on Earth occur as well. Changes in the planet's atmosphere and observations of lightning, have been attributed to ongoing volcanic eruptions, although there is no confirmation of whether or not Venus is still volcanically active. However, radar sounding by the Magellan probe revealed evidence for comparatively recent volcanic activity at Venus's highest volcano Maat Mons, in the form of ash flows near the summit and on the northern flank.
There are several extinct volcanoes on Mars, four of which are vast shield volcanoes far bigger than any on Earth. They include Arsia Mons, Ascraeus Mons, Hecates Tholus, Olympus Mons, and Pavonis Mons. These volcanoes have been extinct for many millions of years,[5] but the European Mars Express spacecraft has found evidence that volcanic activity may have occurred on Mars in the recent past as well.[5]
Jupiter's moon Io is the most volcanically active object in the solar system because of tidal interaction with Jupiter. It is covered with volcanoes that erupt sulfur, sulfur dioxide and silicate rock, and as a result, Io is constantly being resurfaced. Its lavas are the hottest known anywhere in the solar system, with temperatures exceeding 1,800 K (1,500 °C). In February 2001, the largest recorded volcanic eruptions in the solar system occurred on Io.[6] Europa, the smallest of Jupiter's Galilean moons, also appears to have an active volcanic system, except that its volcanic activity is entirely in the form of water, which freezes into ice on the frigid surface. This process is known as cryovolcanism, and is apparently most common on the moons of the outer planets of the solar system.
In 1989 the Voyager 2 spacecraft observed cryovolcanoes (ice volcanoes) on Triton, a moon of Neptune, and in 2005 the Cassini-Huygens probe photographed fountains of frozen particles erupting from Enceladus, a moon of Saturn.[7] The ejecta may be composed of water, liquid nitrogen, dust, or methane compounds. Cassini-Huygens also found evidence of a methane-spewing cryovolcano on the Saturnian moon Titan, which is believed to be a significant source of the methane found in its atmosphere.[8] It is theorized that cryovolcanism may also be present on the Kuiper Belt Object Quaoar.
# Etymology
Volcano is thought to derive from Vulcano, a volcanic island in the Aeolian Islands of Italy whose name in turn originates from Vulcan, the name of a god of fire in Roman mythology. The study of volcanoes is called volcanology, sometimes spelled vulcanology.
The Roman name for the island Vulcano has contributed the word for volcano in most modern European languages.
# In culture
## Past beliefs
Many ancient accounts ascribe volcanic eruptions to supernatural causes, such as the actions of gods or demigods. To the ancient Greeks, volcanoes' capricious power could only be explained as acts of the gods, while 16th/17th-century German astronomer Johannes Kepler believed they were ducts for the Earth's tears. [9] One early idea counter to this was proposed by Jesuit Athanasius Kircher (1602–1680), who witnessed eruptions of Mount Etna and Stromboli, then visited the crater of Vesuvius and published his view of an Earth with a central fire connected to numerous others caused by the burning of sulfur, bitumen and coal.
Various explanations were proposed for volcano behavior before the modern understanding of the Earth's mantle structure as a semisolid material was developed. For decades after awareness that compression and radioactive materials may be heat sources, their contributions were specifically discounted. Volcanic action was often attributed to chemical reactions and a thin layer of molten rock near the surface.
## Heraldry
Volcanoes appear as a charge in heraldry.
# Panoramas | https://www.wikidoc.org/index.php/Volcano | |
b79e3c1fb16d67674111fae22bfd000dcad9e0d0 | wikidoc | Voltage | Voltage
Voltage (sometimes also called electric or electrical tension) is the difference of electrical potential between two points of an electrical or electronic circuit, expressed in volts. It measures the potential energy of an electric field to cause an electric current in an electrical conductor. Depending on the difference of electrical potential it is called extra low voltage, low voltage, high voltage or extra high voltage.
# Explanation
Between two points in an electric field, such as exists in an electrical circuit, the difference in their electrical potentials is known as the electrical potential difference. This difference is proportional to the force that tends to push electrons or other charge-carriers from one point to the other. Electrical potential difference can be thought of as the ability to move electrical charge through a resistance. At a time in physics when the word force was used loosely, the potential difference was named the electromotive force or EMF—a term which is still used in certain contexts.
Voltage is a property of an electric field, not individual electrons. An electron moving across a voltage difference experiences a net change in energy, often measured in electron-volts. This effect is analogous to a mass falling through a given height difference in a gravitational field.
When using the term 'potential difference' or voltage, one must be clear about the two points between which the voltage is specified or measured. There are two ways in which the term is used. This can lead to some confusion.
## Voltage with respect to a common point
One way in which the term voltage is used is when specifying the voltage of a point in a circuit. When this is done, it is understood that the voltage is usually being specified or measured with respect to a stable and unchanging point in the circuit that is known as ground or common. This voltage is really a voltage difference, one of the two points being the reference point, which is ground. A voltage can be positive or negative. "High" or "low" voltage may refer to the magnitude (the absolute value relative to the reference point). Thus, a large negative voltage may be referred to as a high voltage. Other authors may refer to a voltage that is more negative as being "lower."
## Voltage between two stated points
Another usage of the term "voltage" is in specifying how many volts are across an electrical device (such as a resistor). In this case, the "voltage," or, more accurately, the "voltage across the device," is really the first voltage taken, relative to ground, on one terminal of the device minus a second voltage taken, relative to ground, on the other terminal of the device. In practice, the voltage across a device can be measured directly and safely using a voltmeter that is isolated from ground, provided that the maximum voltage capability of the voltmeter is not exceeded.
Two points in an electric circuit that are connected by an "ideal conductor," that is, a conductor without resistance and not within a changing magnetic field, have a potential difference of zero. However, other pairs of points may also have a potential difference of zero. If two such points are connected with a conductor, no current will flow through the connection.
## Addition of voltages
Voltage is additive in the following sense: the voltage between A and C is the sum of the voltage between A and B and the voltage between B and C. The various voltages in a circuit can be computed using Kirchhoff's circuit laws.
When talking about alternating current (AC) there is a difference between instantaneous voltage and average voltage. Instantaneous voltages can be added as for direct current (DC), but average voltages can be meaningfully added only when they apply to signals that all have the same frequency and phase.
## Hydraulic analogy
If one imagines water circulating in a network of pipes, driven by pumps in the absence of gravity, as an analogy of an electrical circuit, then the potential difference corresponds to the fluid pressure difference between two points. If there is a pressure difference between two points, then water flowing from the first point to the second will be able to do work, such as driving a turbine.
This hydraulic analogy is a useful method of teaching a range of electrical concepts. In a hydraulic system, the work done to move water is equal to the pressure multiplied by the volume of water moved. Similarly, in an electrical circuit, the work done to move electrons or other charge-carriers is equal to 'electrical pressure' (an old term for voltage) multiplied by the quantity of electrical charge moved. Voltage is a convenient way of quantifying the ability to do work. In relation to electric current, the larger the gradient (voltage or hydraulic) the greater the current (assuming resistance is constant).
## Mathematical definition
The electrical potential difference is defined as the amount of work needed to move a unit electric charge from the second point to the first, or equivalently, the amount of work that a unit charge flowing from the first point to the second can perform. The potential difference between two points a and b is the line integral of the electric field E:
# Useful formulae
## DC circuits
Where V = voltage/potential difference, I = current intensity, R = resistance, P = power/watts
## AC circuits
Where V=voltage, I=current, R=resistance, P=true power, Z=impedance, φ=phasor angle between I and V
## AC conversions
Where Vpk=peak voltage, Vppk=peak-to-peak voltage, Vavg=average voltage over a half-cycle, Vrms=effective (root mean square) voltage, and we assumed a sinusoidal wave of the form V_{pk} \sin(\omega t - k x) , with a period T = 2\pi/\omega , and where the angle brackets (in the root-mean-square equation) denote a time average over an entire period.
## Total voltage
Voltage sources and drops in series:
Voltage sources and drops in parallel:
Where n \!\ is the nth voltage source or drop
## Voltage drops
Across a resistor (Resistor R):
Across a capacitor (Capacitor C):
Across an inductor (Inductor L):
Where V=voltage, I=current, R=resistance, X=reactance.
# Measuring instruments
Instruments for measuring potential differences include the voltmeter, the potentiometer (measurement device), and the oscilloscope. The voltmeter works by measuring the current through a fixed resistor, which, according to Ohm's Law, is proportional to the potential difference across the resistor. The potentiometer works by balancing the unknown voltage against a known voltage in a bridge circuit. The cathode-ray oscilloscope works by amplifying the potential difference and using it to deflect an electron beam from a straight path, so that the deflection of the beam is proportional to the potential difference.
# Safety
Electrical safety is discussed in the articles on High voltage and Electric shock. | Voltage
Voltage (sometimes also called electric or electrical tension) is the difference of electrical potential between two points of an electrical or electronic circuit, expressed in volts.[1] It measures the potential energy of an electric field to cause an electric current in an electrical conductor. Depending on the difference of electrical potential it is called extra low voltage, low voltage, high voltage or extra high voltage.
# Explanation
Between two points in an electric field, such as exists in an electrical circuit, the difference in their electrical potentials is known as the electrical potential difference. This difference is proportional to the force that tends to push electrons or other charge-carriers from one point to the other. Electrical potential difference can be thought of as the ability to move electrical charge through a resistance. At a time in physics when the word force was used loosely, the potential difference was named the electromotive force or EMF—a term which is still used in certain contexts.
Voltage is a property of an electric field, not individual electrons. An electron moving across a voltage difference experiences a net change in energy, often measured in electron-volts. This effect is analogous to a mass falling through a given height difference in a gravitational field.
When using the term 'potential difference' or voltage, one must be clear about the two points between which the voltage is specified or measured. There are two ways in which the term is used. This can lead to some confusion.
## Voltage with respect to a common point
One way in which the term voltage is used is when specifying the voltage of a point in a circuit. When this is done, it is understood that the voltage is usually being specified or measured with respect to a stable and unchanging point in the circuit that is known as ground or common. This voltage is really a voltage difference, one of the two points being the reference point, which is ground. A voltage can be positive or negative. "High" or "low" voltage may refer to the magnitude (the absolute value relative to the reference point). Thus, a large negative voltage may be referred to as a high voltage. Other authors may refer to a voltage that is more negative as being "lower."
## Voltage between two stated points
Another usage of the term "voltage" is in specifying how many volts are across an electrical device (such as a resistor). In this case, the "voltage," or, more accurately, the "voltage across the device," is really the first voltage taken, relative to ground, on one terminal of the device minus a second voltage taken, relative to ground, on the other terminal of the device. In practice, the voltage across a device can be measured directly and safely using a voltmeter that is isolated from ground, provided that the maximum voltage capability of the voltmeter is not exceeded.
Two points in an electric circuit that are connected by an "ideal conductor," that is, a conductor without resistance and not within a changing magnetic field, have a potential difference of zero. However, other pairs of points may also have a potential difference of zero. If two such points are connected with a conductor, no current will flow through the connection.
## Addition of voltages
Voltage is additive in the following sense: the voltage between A and C is the sum of the voltage between A and B and the voltage between B and C. The various voltages in a circuit can be computed using Kirchhoff's circuit laws.
When talking about alternating current (AC) there is a difference between instantaneous voltage and average voltage. Instantaneous voltages can be added as for direct current (DC), but average voltages can be meaningfully added only when they apply to signals that all have the same frequency and phase.
## Hydraulic analogy
If one imagines water circulating in a network of pipes, driven by pumps in the absence of gravity, as an analogy of an electrical circuit, then the potential difference corresponds to the fluid pressure difference between two points. If there is a pressure difference between two points, then water flowing from the first point to the second will be able to do work, such as driving a turbine.
This hydraulic analogy is a useful method of teaching a range of electrical concepts. In a hydraulic system, the work done to move water is equal to the pressure multiplied by the volume of water moved. Similarly, in an electrical circuit, the work done to move electrons or other charge-carriers is equal to 'electrical pressure' (an old term for voltage) multiplied by the quantity of electrical charge moved. Voltage is a convenient way of quantifying the ability to do work. In relation to electric current, the larger the gradient (voltage or hydraulic) the greater the current (assuming resistance is constant).
## Mathematical definition
The electrical potential difference is defined as the amount of work needed to move a unit electric charge from the second point to the first, or equivalently, the amount of work that a unit charge flowing from the first point to the second can perform. The potential difference between two points a and b is the line integral of the electric field E:
# Useful formulae
## DC circuits
Where V = voltage/potential difference, I = current intensity, R = resistance, P = power/watts
## AC circuits
Where V=voltage, I=current, R=resistance, P=true power, Z=impedance, φ=phasor angle between I and V
## AC conversions
Where Vpk=peak voltage, Vppk=peak-to-peak voltage, Vavg=average voltage over a half-cycle, Vrms=effective (root mean square) voltage, and we assumed a sinusoidal wave of the form <math> V_{pk} \sin(\omega t - k x) </math>, with a period <math> T = 2\pi/\omega </math>, and where the angle brackets (in the root-mean-square equation) denote a time average over an entire period.
## Total voltage
Voltage sources and drops in series:
Voltage sources and drops in parallel:
Where <math> n \!\ </math> is the nth voltage source or drop
## Voltage drops
Across a resistor (Resistor R):
Across a capacitor (Capacitor C):
Across an inductor (Inductor L):
Where V=voltage, I=current, R=resistance, X=reactance.
# Measuring instruments
Instruments for measuring potential differences include the voltmeter, the potentiometer (measurement device), and the oscilloscope. The voltmeter works by measuring the current through a fixed resistor, which, according to Ohm's Law, is proportional to the potential difference across the resistor. The potentiometer works by balancing the unknown voltage against a known voltage in a bridge circuit. The cathode-ray oscilloscope works by amplifying the potential difference and using it to deflect an electron beam from a straight path, so that the deflection of the beam is proportional to the potential difference.
# Safety
Electrical safety is discussed in the articles on High voltage and Electric shock. | https://www.wikidoc.org/index.php/Voltage | |
f344eb3bf00daa4675abf7ec78afb297a0b1db3a | wikidoc | WBR1056 | WBR1056
- ↑ Jump up to: 1.0 1.1 Gupta K, Hooton TM, Naber KG, Wullt B, Colgan R, Miller LG; et al. (2011). "International clinical practice guidelines for the treatment of acute uncomplicated cystitis and pyelonephritis in women: A 2010 update by the Infectious Diseases Society of America and the European Society for Microbiology and Infectious Diseases". Clin Infect Dis. 52 (5): e103–20. doi:10.1093/cid/ciq257. PMID 21292654.CS1 maint: Explicit use of et al. (link) CS1 maint: Multiple names: authors list (link) .mw-parser-output cite.citation{font-style:inherit}.mw-parser-output q{quotes:"\"""\"""'""'"}.mw-parser-output code.cs1-code{color:inherit;background:inherit;border:inherit;padding:inherit}.mw-parser-output .cs1-lock-free a{background:url("")no-repeat;background-position:right .1em center}.mw-parser-output .cs1-lock-limited a,.mw-parser-output .cs1-lock-registration a{background:url("")no-repeat;background-position:right .1em center}.mw-parser-output .cs1-lock-subscription a{background:url("")no-repeat;background-position:right .1em center}.mw-parser-output .cs1-subscription,.mw-parser-output .cs1-registration{color:#555}.mw-parser-output .cs1-subscription span,.mw-parser-output .cs1-registration span{border-bottom:1px dotted;cursor:help}.mw-parser-output .cs1-hidden-error{display:none;font-size:100%}.mw-parser-output .cs1-visible-error{display:none;font-size:100%}.mw-parser-output .cs1-subscription,.mw-parser-output .cs1-registration,.mw-parser-output .cs1-format{font-size:95%}.mw-parser-output .cs1-kern-left,.mw-parser-output .cs1-kern-wl-left{padding-left:0.2em}.mw-parser-output .cs1-kern-right,.mw-parser-output .cs1-kern-wl-right{padding-right:0.2em}
- ↑ Kahlmeter, G. (2003). "An international survey of the antimicrobial susceptibility of pathogens from uncomplicated urinary tract infections: the ECO.SENS Project". J Antimicrob Chemother. 51 (1): 69–76. PMID 12493789. Unknown parameter |month= ignored (help)
- ↑ Naber, KG.; Schito, G.; Botto, H.; Palou, J.; Mazzei, T. (2008). "Surveillance study in Europe and Brazil on clinical aspects and Antimicrobial Resistance Epidemiology in Females with Cystitis (ARESC): implications for empiric therapy". Eur Urol. 54 (5): 1164–75. doi:10.1016/j.eururo.2008.05.010. PMID 18511178. Unknown parameter |month= ignored (help) | WBR1056
- ↑ Jump up to: 1.0 1.1 Gupta K, Hooton TM, Naber KG, Wullt B, Colgan R, Miller LG; et al. (2011). "International clinical practice guidelines for the treatment of acute uncomplicated cystitis and pyelonephritis in women: A 2010 update by the Infectious Diseases Society of America and the European Society for Microbiology and Infectious Diseases". Clin Infect Dis. 52 (5): e103–20. doi:10.1093/cid/ciq257. PMID 21292654.CS1 maint: Explicit use of et al. (link) CS1 maint: Multiple names: authors list (link) .mw-parser-output cite.citation{font-style:inherit}.mw-parser-output q{quotes:"\"""\"""'""'"}.mw-parser-output code.cs1-code{color:inherit;background:inherit;border:inherit;padding:inherit}.mw-parser-output .cs1-lock-free a{background:url("https://upload.wikimedia.org/wikipedia/commons/thumb/6/65/Lock-green.svg/9px-Lock-green.svg.png")no-repeat;background-position:right .1em center}.mw-parser-output .cs1-lock-limited a,.mw-parser-output .cs1-lock-registration a{background:url("https://upload.wikimedia.org/wikipedia/commons/thumb/d/d6/Lock-gray-alt-2.svg/9px-Lock-gray-alt-2.svg.png")no-repeat;background-position:right .1em center}.mw-parser-output .cs1-lock-subscription a{background:url("https://upload.wikimedia.org/wikipedia/commons/thumb/a/aa/Lock-red-alt-2.svg/9px-Lock-red-alt-2.svg.png")no-repeat;background-position:right .1em center}.mw-parser-output .cs1-subscription,.mw-parser-output .cs1-registration{color:#555}.mw-parser-output .cs1-subscription span,.mw-parser-output .cs1-registration span{border-bottom:1px dotted;cursor:help}.mw-parser-output .cs1-hidden-error{display:none;font-size:100%}.mw-parser-output .cs1-visible-error{display:none;font-size:100%}.mw-parser-output .cs1-subscription,.mw-parser-output .cs1-registration,.mw-parser-output .cs1-format{font-size:95%}.mw-parser-output .cs1-kern-left,.mw-parser-output .cs1-kern-wl-left{padding-left:0.2em}.mw-parser-output .cs1-kern-right,.mw-parser-output .cs1-kern-wl-right{padding-right:0.2em}
- ↑ Kahlmeter, G. (2003). "An international survey of the antimicrobial susceptibility of pathogens from uncomplicated urinary tract infections: the ECO.SENS Project". J Antimicrob Chemother. 51 (1): 69–76. PMID 12493789. Unknown parameter |month= ignored (help)
- ↑ Naber, KG.; Schito, G.; Botto, H.; Palou, J.; Mazzei, T. (2008). "Surveillance study in Europe and Brazil on clinical aspects and Antimicrobial Resistance Epidemiology in Females with Cystitis (ARESC): implications for empiric therapy". Eur Urol. 54 (5): 1164–75. doi:10.1016/j.eururo.2008.05.010. PMID 18511178. Unknown parameter |month= ignored (help) | https://www.wikidoc.org/index.php/WBR1056 | |
64dfcc2777b1705809761433164a36df0931dc10 | wikidoc | WHSC1L1 | WHSC1L1
Histone-lysine N-methyltransferase NSD3 is an enzyme that in humans is encoded by the WHSC1L1 gene.
This gene is related to the Wolf-Hirschhorn syndrome candidate-1 gene and encodes a protein with PWWP (proline-tryptophan-tryptophan-proline) domains. The function of the protein has not been determined. Two alternatively spliced variants have been described.
The WHSC1L1 gene is amplified in several cancers, including lung cancer and head and neck cancer, and may play a role in carcinogenesis. | WHSC1L1
Histone-lysine N-methyltransferase NSD3 is an enzyme that in humans is encoded by the WHSC1L1 gene.[1][2]
This gene is related to the Wolf-Hirschhorn syndrome candidate-1 gene and encodes a protein with PWWP (proline-tryptophan-tryptophan-proline) domains. The function of the protein has not been determined. Two alternatively spliced variants have been described.[2]
The WHSC1L1 gene is amplified in several cancers, including lung cancer and head and neck cancer, and may play a role in carcinogenesis.[3][4] | https://www.wikidoc.org/index.php/WHSC1L1 | |
018a3a6d5646be448b834d93c2518258d08e9ed7 | wikidoc | WP:SECT | WP:SECT
A page can be divided into sections, using the section heading syntax.
# Creation and numbering of sections
Sections are created by creating their headings, as below:
Please do not use only one equals sign on a side (=text here=); this causes a title the size of the page name, which is taken care of automatically.
With the preference setting Auto-number headings section numbering appears at each heading.
Section names can best be unique within a page. This applies even for the names of subsections. Disadvantages of duplicate section names, even as subsections of different sections, include:
- after section editing one confusingly arrives at the wrong section; see also below.
- the automatic edit summary on editing a section is ambiguous
A section (or sections) of a page can be an included separate page (or template), without changing the appearance of a page. See Help:Template#Composite_pages. This way a separate edit history is in effect provided for the section. Also this allows watching it separately.
In a page calling a template with sections, the sections in the template are numbered according to their position in the rendered page, e.g. if the template tag is in the third section, then the first section of the template is numbered four. Any text in the template before its first section shows up as part of the section with the template tag, and any text after the tag before a new heading shows up as part of the last section of the template. This may be done deliberately, but can usually better be avoided (see also below).
# Table of contents (TOC)
For each page with more than three headings, a table of contents (TOC) is automatically generated from the section headings, unless:
- (for a user) preferences are set to turn it off
- (for an article) the magic word __NOTOC__ (with two underscores on either side of the word) is added in the edit box
When either __FORCETOC__ or __TOC__ (with two underscores on either side of the word) is placed in the wikitext, a TOC is added even if the page has fewer than four headings.
With __FORCETOC__, the TOC is placed before the first section heading. With __TOC__, it is placed at the same position where this code is placed. This allows any positioning, e.g. on the right or in a table cell. In old versions of MediaWiki, it also allows multiple occurrence, e.g. in every section (However, this seems only useful if the sections are long, so that the TOCs take up only a small part of the total space.).
There may be some introductory text before the TOC, known as the "lead". Although usually a heading after the TOC is preferable, __TOC__ can be used to avoid being forced to insert a meaningless heading just to position the TOC correctly, i.e., not too low.
Using __NOTOC__ it is possible to disable the normal Table of Contents. Section links as explained below allow to create compact ToCs, e.g. alphabetical ] ] etc.
Summary:
The Table of contents can be forced onto a floating table on the right hand of the screen with the code below:
## Globally limiting the TOC depth
It is possible to limit the depth of sub-sections to show in the TOC globally using $wgMaxTocLevel. If configuration setting $wgMaxTocLevel in LocalSettings.php is set to 3 for example, only first and second level headings show up in the TOC.
Until version 1.10.0rc1, there is a bug in the parser making a limited TOC display incorrectly. A simple solution is proposed in bug report 6204.
# Section linking
In the HTML code for each section there is an anchor Template:H:mlw with both "name" and "id" attributes holding the section title. This enables linking directly to sections. These section anchors are automatically used by MediaWiki when it generates a Table of Contents for the page, and therefore when you click a section heading in the ToC, you will jump to the section. You can also use section anchors to manually link directly to one section within a page.
The html code generated at the beginning of this section, for example, is:
A link to this section (Section Linking) looks like this:
To link to a section in the same page you can use ], and to link to a section in another page ].
The anchors disregard the depth of the section; a link to a subsection or sub-subsection etc. will be ] and ] etc.
An underscore and number are appended to duplicate section names. E.g. for three sections named "Example", the names (for section linking) will be "Example", "Example_2" and "Example_3". However, after editing section "Example_2" or "Example_3" (see below), one, confusingly, arrives at section "Example" from the edit summary.
If a section has a blank space as heading, it results in a link in the TOC that does not work. For a similar effect see NS:0.
To create an anchor target without a section heading, you can use a span, for example:, however this won't work with some very old browsers.
Note that using the date formatting feature in section headings complicates section linking.
An internal link in a section heading does not give complications in terms of section linking:
- #Demo_a
- Help:Section#Demo_http:.2F.2Fa
- :Section#Demo_http:.2F.2Fa
For linking to an arbitrary position in a page see linking to a page.
## Section linking and redirects
A link that specifies a section of a redirect page corresponds to a link to that section of the target of the redirect.
A redirect to a section of a page may also work in some environments , try e.g. the redirect page Section linking and redirects. (One might have to force reload CSS style sheets.)
A complication is that, unlike renaming a page, renaming a section does not create some kind of redirect. Also there is no separate backlink feature for sections, pages linking to the section are included in the list of pages linking to the page. Possible workarounds:
- Instead of linking directly to a section, link to a page that redirects to the section; when the name of the section is changed, change the redirect target. This method also provides more or less a "what links here" for sections (look for redirects linking to the page, select the one linking to the section; this may be recognized from the name even if the section name has changed).
- Put an anchor and link to that
- Put a comment in the wikitext at the start of a section listing pages that link to the section
- Make the section a separate page/template and either transclude it into, or just link to it from, its parent page; instead of linking to the section one can then link to the separate page.
Redirect pages can be categorized by adding a category tag after the redirect command. In the case that the target of the redirect is a section this has to some extent the effect of categorizing the section: through the redirect the category page links to the section; however, unless an explicit link is put, the section does not link to the category. On the category page redirects are displayed with class redirect-in-category, so they can be shown in e.g. italics; this can be defined in MediaWiki:Common.css. See also Template:Mlww.
# Section editing
Sections can be separately edited by clicking special edit links labeled "" by the heading, or by right clicking on the section heading, depending on the preferences set. This is called "section editing feature". Section editing feature will take you to an edit page by a URl such as
:Section&action=edit§ion=2
Note that here section numbers are used, not section titles; subsections have a single number, e.g. section 2.1 may be numbered 3, section 3 is then numbered 4, etc. You can also directly type in such URls in the address bar of your browser.
This is convenient if the edit does not involve other sections and one needs not have the text of other sections at hand during the edit (or if one needs it, open the section edit link in a new window, or during section editing, open the main page in a different window). Section editing alleviates some problems of large pages.
"__NOEDITSECTION__" anywhere on the page will remove the edit links. It will not disable section editing itself; right clicking on the section heading and the url still work.
Inserting a section can be done by editing either the section before or after it, merging with the previous section by deleting the heading.
Adding a section at the end can also be done with a URL like :Sandbox&action=edit§ion=new . On talk pages a special link labeled "+" or "Post a new comment" is provided for this. In this case, a text box titled "Subject/headline" will appear and the content you type in it will become the section heading as well as the edit summary of the edit.
## Editing before the first section
In general, no particular link for editing the introductory text before the first section heading is provided. However, section editing feature can also be applied to this part by giving 0 as the section number such as :Section&action=edit§ion=0 . A less cumbersome way to obtain this link is to use any section edit link of the page, and change the number of the section to zero.
Javascript can also create this URL, see w:en:Wikipedia:WikiProject User scripts/Scripts/Edit Top.
The {{Edit-first-section}} and {{Edit-top-section}} templates create an edit link for the section 0. Both are positioned slightly different. Copy these templates to your wiki.
See also Help:Section editing demo.
## Preview
The preview in section editing does not always show the same as the corresponding part of the full page, e.g. if on the full page an image in the previous section intrudes into the section concerned.
The edit page shows the list of templates used on the whole page, i.e. also the templates used in other sections.
## Subsections
Subsections are included in the part of the section that is edited. Section numbering is relative to the part that is edited, so on the relative top level there is always just number 1, relative subsections all have numbers starting with 1: 1.1., 1.2, etc.; e.g., when editing subsection 3.2, sub-subsection 3.2.4 is numbered 1.4. However, the heading format is according to the absolute level.
## Editing a page with large sections
If a page has very large sections, or is very large and has no division into sections, and one's browser or connection does not allow editing of such a large section, then one can still:
- append a section by specifying a large section number (too large does not matter); however, one has to start with a blank line before the new section heading
- append content to the last section by not starting with a section heading; however, with the limitations of one's browser or connection, one cannot revert this, or edit one's new text.
If one can view the wikitext of a large section, one can divide the page into smaller sections by step by step appending one, and finally deleting the original content (this can be done one large section at a time). Thus temporarily there is partial duplication of the content, so it is useful to put an explanation in the edit summary.
Help:Editing sections of included templates
## Sections within parser functions
If a section heading is created conditionally using a parser function, either directly or by conditionally transcluding a template with sections, edit links of this and subsequent sections will edit the wrong section (although the page (including TOC) is correctly displayed and the TOC links correctly). This is because section counting for producing the edit links is done after expanding the parser functions, whereas when the edit page is loaded, only those sections are counted which statically appear in the page (or the respective template).
This is not a bug but a consequence of the way section editing is implemented, so the solutions are the obvious ones: either avoid creating sections via parser functions, or disable section editing.
## Editing a footnote
To edit a footnote rendered in a section containing the code {{reflist|2}}, edit the section with the footnote mark referring to it, see Help:Footnotes.
# Sections vs. separate pages vs. transclusion
Advantages of separate pages:
- what links here feature
- separate edit histories
- the Template:Peisl applies per page
- automatic redirect on renaming
- loading a small page is faster than loading a large page
- can separately be put in categories (however, see also below)
- with Semantic MediaWiki: have separate annotations
Advantages of one large page with sections:
- loading one large page is faster and more convenient than loading several small ones
- searching within one large page (the page itself or the wikitext) with a local search function is faster and in some respects better than searching several pages (for which one has to search the whole project); also the TOC provides for convenient navigation.
- enforces the cohesion of a concept that while having several definitions needs independent editing.
An alternative is composing a page of other pages using the template feature (creating a compound document by Transclusion). This allows easy searching within the combined rendered page, but not in the combined wikitext. As a disadvantage, a title for each page has to be provided. For the pre-expand include size limit this is disadvantageous even compared with one large page: the pre-expand include size is the sum of the pre-expand include sizes of the components plus the sum of sizes of the wikitexts of the components.
# Sections for demo above
## Demo a
This section is linked to from #Section linking.
## Demo
This section is linked to from #Section linking. | WP:SECT
Template:H:h
A page can be divided into sections, using the section heading syntax.
# Creation and numbering of sections
Sections are created by creating their headings, as below:
Please do not use only one equals sign on a side (=text here=); this causes a title the size of the page name, which is taken care of automatically.
With the preference setting Auto-number headings section numbering appears at each heading.
Section names can best be unique within a page. This applies even for the names of subsections. Disadvantages of duplicate section names, even as subsections of different sections, include:
- after section editing one confusingly arrives at the wrong section; see also below.
- the automatic edit summary on editing a section is ambiguous
A section (or sections) of a page can be an included separate page (or template), without changing the appearance of a page. See Help:Template#Composite_pages. This way a separate edit history is in effect provided for the section. Also this allows watching it separately.
In a page calling a template with sections, the sections in the template are numbered according to their position in the rendered page, e.g. if the template tag is in the third section, then the first section of the template is numbered four. Any text in the template before its first section shows up as part of the section with the template tag, and any text after the tag before a new heading shows up as part of the last section of the template. This may be done deliberately, but can usually better be avoided (see also below).
# Table of contents (TOC)
For each page with more than three headings, a table of contents (TOC) is automatically generated from the section headings, unless:
- (for a user) preferences are set to turn it off
- (for an article) the magic word __NOTOC__ (with two underscores on either side of the word) is added in the edit box
When either __FORCETOC__ or __TOC__ (with two underscores on either side of the word) is placed in the wikitext, a TOC is added even if the page has fewer than four headings.
With __FORCETOC__, the TOC is placed before the first section heading. With __TOC__, it is placed at the same position where this code is placed. This allows any positioning, e.g. on the right or in a table cell. In old versions of MediaWiki, it also allows multiple occurrence, e.g. in every section (However, this seems only useful if the sections are long, so that the TOCs take up only a small part of the total space.).
There may be some introductory text before the TOC, known as the "lead". Although usually a heading after the TOC is preferable, __TOC__ can be used to avoid being forced to insert a meaningless heading just to position the TOC correctly, i.e., not too low.
Using __NOTOC__ it is possible to disable the normal Table of Contents. Section links as explained below allow to create compact ToCs, e.g. alphabetical [[#A|A]] [[#B|B]] etc.
Summary:
Template:H:TOC variables
The Table of contents can be forced onto a floating table on the right hand of the screen with the code below:
## Globally limiting the TOC depth
It is possible to limit the depth of sub-sections to show in the TOC globally using $wgMaxTocLevel. If configuration setting $wgMaxTocLevel in LocalSettings.php is set to 3 for example, only first and second level headings show up in the TOC.
Until version 1.10.0rc1, there is a bug in the parser making a limited TOC display incorrectly. A simple solution is proposed in bug report 6204.
# Section linking
In the HTML code for each section there is an anchor Template:H:mlw with both "name" and "id" attributes holding the section title. This enables linking directly to sections. These section anchors are automatically used by MediaWiki when it generates a Table of Contents for the page, and therefore when you click a section heading in the ToC, you will jump to the section. You can also use section anchors to manually link directly to one section within a page.
The html code generated at the beginning of this section, for example, is:
A link to this section (Section Linking) looks like this:
[[Help:Section#Section_linking|Section Linking]]
To link to a section in the same page you can use [[#section name|displayed text]], and to link to a section in another page [[page name#section name|displayed text]].
The anchors disregard the depth of the section; a link to a subsection or sub-subsection etc. will be [[#subsection name]] and [[#sub-subsection name]] etc.
An underscore and number are appended to duplicate section names. E.g. for three sections named "Example", the names (for section linking) will be "Example", "Example_2" and "Example_3". However, after editing section "Example_2" or "Example_3" (see below), one, confusingly, arrives at section "Example" from the edit summary.
If a section has a blank space as heading, it results in a link in the TOC that does not work. For a similar effect see NS:0.
To create an anchor target without a section heading, you can use a span, for example:<span id="anchor_name"></span>, however this won't work with some very old browsers.
Note that using the date formatting feature in section headings complicates section linking.
An internal link in a section heading does not give complications in terms of section linking:
- #Demo_a
- Help:Section#Demo_http:.2F.2Fa
- http://meta.wikimedia.org/wiki/Help:Section#Demo_http:.2F.2Fa
For linking to an arbitrary position in a page see linking to a page.
## Section linking and redirects
A link that specifies a section of a redirect page corresponds to a link to that section of the target of the redirect.
A redirect to a section of a page may also work in some environments [1], try e.g. the redirect page Section linking and redirects. (One might have to force reload CSS style sheets.)
A complication is that, unlike renaming a page, renaming a section does not create some kind of redirect. Also there is no separate backlink feature for sections, pages linking to the section are included in the list of pages linking to the page. Possible workarounds:
- Instead of linking directly to a section, link to a page that redirects to the section; when the name of the section is changed, change the redirect target. This method also provides more or less a "what links here" for sections (look for redirects linking to the page, select the one linking to the section; this may be recognized from the name even if the section name has changed).
- Put an anchor and link to that
- Put a comment in the wikitext at the start of a section listing pages that link to the section
- Make the section a separate page/template and either transclude it into, or just link to it from, its parent page; instead of linking to the section one can then link to the separate page.
Redirect pages can be categorized by adding a category tag after the redirect command. In the case that the target of the redirect is a section this has to some extent the effect of categorizing the section: through the redirect the category page links to the section; however, unless an explicit link is put, the section does not link to the category. On the category page redirects are displayed with class redirect-in-category, so they can be shown in e.g. italics; this can be defined in MediaWiki:Common.css. See also Template:Mlww.
# Section editing
Sections can be separately edited by clicking special edit links labeled "[edit]" by the heading, or by right clicking on the section heading, depending on the preferences set. This is called "section editing feature". Section editing feature will take you to an edit page by a URl such as
https://www.wikidoc.org/w/wiki.phtml?title=Help:Section&action=edit§ion=2
Note that here section numbers are used, not section titles; subsections have a single number, e.g. section 2.1 may be numbered 3, section 3 is then numbered 4, etc. You can also directly type in such URls in the address bar of your browser.
This is convenient if the edit does not involve other sections and one needs not have the text of other sections at hand during the edit (or if one needs it, open the section edit link in a new window, or during section editing, open the main page in a different window). Section editing alleviates some problems of large pages.
"__NOEDITSECTION__" anywhere on the page will remove the edit links. It will not disable section editing itself; right clicking on the section heading and the url still work.
Inserting a section can be done by editing either the section before or after it, merging with the previous section by deleting the heading.
Adding a section at the end can also be done with a URL like http://meta.wikimedia.org/w/wiki.phtml?title=Meta:Sandbox&action=edit§ion=new . On talk pages a special link labeled "+" or "Post a new comment" is provided for this. In this case, a text box titled "Subject/headline" will appear and the content you type in it will become the section heading as well as the edit summary of the edit.
## Editing before the first section
In general, no particular link for editing the introductory text before the first section heading is provided. However, section editing feature can also be applied to this part by giving 0 as the section number such as https://www.wikidoc.org/w/wiki.phtml?title=Help:Section&action=edit§ion=0 . A less cumbersome way to obtain this link is to use any section edit link of the page, and change the number of the section to zero.
Javascript can also create this URL, see w:en:Wikipedia:WikiProject User scripts/Scripts/Edit Top.
The {{Edit-first-section}} and {{Edit-top-section}} templates create an edit link for the section 0. Both are positioned slightly different. Copy these templates to your wiki.
See also Help:Section editing demo.
## Preview
The preview in section editing does not always show the same as the corresponding part of the full page, e.g. if on the full page an image in the previous section intrudes into the section concerned.
The edit page shows the list of templates used on the whole page, i.e. also the templates used in other sections.
## Subsections
Subsections are included in the part of the section that is edited. Section numbering is relative to the part that is edited, so on the relative top level there is always just number 1, relative subsections all have numbers starting with 1: 1.1., 1.2, etc.; e.g., when editing subsection 3.2, sub-subsection 3.2.4 is numbered 1.4. However, the heading format is according to the absolute level.
## Editing a page with large sections
If a page has very large sections, or is very large and has no division into sections, and one's browser or connection does not allow editing of such a large section, then one can still:
- append a section by specifying a large section number (too large does not matter); however, one has to start with a blank line before the new section heading
- append content to the last section by not starting with a section heading; however, with the limitations of one's browser or connection, one cannot revert this, or edit one's new text.
If one can view the wikitext of a large section, one can divide the page into smaller sections by step by step appending one, and finally deleting the original content (this can be done one large section at a time). Thus temporarily there is partial duplication of the content, so it is useful to put an explanation in the edit summary.
Help:Editing sections of included templates
## Sections within parser functions
If a section heading is created conditionally using a parser function, either directly or by conditionally transcluding a template with sections, edit links of this and subsequent sections will edit the wrong section (although the page (including TOC) is correctly displayed and the TOC links correctly). This is because section counting for producing the edit links is done after expanding the parser functions, whereas when the edit page is loaded, only those sections are counted which statically appear in the page (or the respective template).
This is not a bug but a consequence of the way section editing is implemented, so the solutions are the obvious ones: either avoid creating sections via parser functions, or disable section editing.
## Editing a footnote
To edit a footnote rendered in a section containing the code {{reflist|2}}, edit the section with the footnote mark referring to it, see Help:Footnotes.
# Sections vs. separate pages vs. transclusion
Advantages of separate pages:
- what links here feature
- separate edit histories
- the Template:Peisl applies per page
- automatic redirect on renaming
- loading a small page is faster than loading a large page
- can separately be put in categories (however, see also below)
- with Semantic MediaWiki: have separate annotations
Advantages of one large page with sections:
- loading one large page is faster and more convenient than loading several small ones
- searching within one large page (the page itself or the wikitext) with a local search function is faster and in some respects better than searching several pages (for which one has to search the whole project); also the TOC provides for convenient navigation.
- enforces the cohesion of a concept that while having several definitions needs independent editing.
An alternative is composing a page of other pages using the template feature (creating a compound document by Transclusion). This allows easy searching within the combined rendered page, but not in the combined wikitext. As a disadvantage, a title for each page has to be provided. For the pre-expand include size limit this is disadvantageous even compared with one large page: the pre-expand include size is the sum of the pre-expand include sizes of the components plus the sum of sizes of the wikitexts of the components.
# Sections for demo above
## Demo a
This section is linked to from #Section linking.
## Demo http://a
This section is linked to from #Section linking. | https://www.wikidoc.org/index.php/WP:SECT | |
3378aa66989984f3fbcfefc9fbc1876752c3e123 | wikidoc | Wasting | Wasting
# Overview
In medical circles, wasting refers to the process by which a debilitating disease causes muscle and fat tissue to "waste" away. Wasting is sometimes referred to as "acute malnutrition" because it is believed that episodes of wasting have a short duration, in contrast to stunting, which is regarded as chronic malnutrition.
# Causes
Wasting can be caused by an extremely low energy intake (e.g., caused by famine), nutrient losses due to infection, or a combination of low intake and high loss. Infections associated with wasting include tuberculosis, chronic diarrhea, and AIDS. The mechanism may involve cachectin - also called tumor necrosis factor, a macrophage-secreted cytokine.
Caretakers and health providers sometimes contribute to wasting by putting the patient on a very restrictive diet.
Voluntary weight loss and eating disorders are excluded as causes of wasting.
# Classification
- Children: Weight-for-height (WFH). In infants under 24 months, recumbent (supine) length is used. WFH as % of median reference value is calculated this way:
Cutoff points may vary, but <80% (close to -2 Z-score) is often used.
- Adults:
Body Mass Index (BMI) is the quotient between weight and height squared (kg/m2). An individual with a BMI < 18.5 is regarded as a case of wasting.
Percent of body weight lost (At Tufts, an unintentional loss of 6% or more in 6 months is regarded as wasting)
- Body Mass Index (BMI) is the quotient between weight and height squared (kg/m2). An individual with a BMI < 18.5 is regarded as a case of wasting.
- Percent of body weight lost (At Tufts, an unintentional loss of 6% or more in 6 months is regarded as wasting) | Wasting
# Overview
In medical circles, wasting refers to the process by which a debilitating disease causes muscle and fat tissue to "waste" away. Wasting is sometimes referred to as "acute malnutrition" because it is believed that episodes of wasting have a short duration, in contrast to stunting, which is regarded as chronic malnutrition.
# Causes
Wasting can be caused by an extremely low energy intake (e.g., caused by famine), nutrient losses due to infection, or a combination of low intake and high loss. Infections associated with wasting include tuberculosis, chronic diarrhea, and AIDS. The mechanism may involve cachectin - also called tumor necrosis factor, a macrophage-secreted cytokine.
Caretakers and health providers sometimes contribute to wasting by putting the patient on a very restrictive diet.
Voluntary weight loss and eating disorders are excluded as causes of wasting.
# Classification
- Children: Weight-for-height (WFH). In infants under 24 months, recumbent (supine) length is used. WFH as % of median reference value is calculated this way:
Cutoff points may vary, but <80% (close to -2 Z-score) is often used.
- Adults:
Body Mass Index (BMI) is the quotient between weight and height squared (kg/m2). An individual with a BMI < 18.5 is regarded as a case of wasting.
Percent of body weight lost (At Tufts, an unintentional loss of 6% or more in 6 months is regarded as wasting)
- Body Mass Index (BMI) is the quotient between weight and height squared (kg/m2). An individual with a BMI < 18.5 is regarded as a case of wasting.
- Percent of body weight lost (At Tufts, an unintentional loss of 6% or more in 6 months is regarded as wasting) | https://www.wikidoc.org/index.php/Wasting | |
dbd5a4f82f4e442cfcfd9d11e8733195d36bc22b | wikidoc | Wavelet | Wavelet
A wavelet is a kind of mathematical function used to divide a given function or continuous-time signal into different frequency components and study each component with a resolution that matches its scale. A wavelet transform is the representation of a function by wavelets. The wavelets are scaled and translated copies (known as "daughter wavelets") of a finite-length or fast-decaying oscillating waveform (known as the "mother wavelet"). Wavelet transforms have advantages over traditional Fourier transforms for representing functions that have discontinuities and sharp peaks, and for accurately deconstructing and reconstructing finite, non-periodic and/or non-stationary signals.
In formal terms, this representation is a wavelet series representation of a square-integrable function with respect to either a complete, orthonormal set of basis functions, or an overcomplete set of Frame of a vector space (also known as a Riesz basis), for the Hilbert space of square integrable functions.
Wavelet transforms are classified into discrete wavelet transforms (DWTs) and continuous wavelet transforms (CWTs). Note that both DWT and CWT are of continuous-time (analog) transforms. They can be used to represent continuous-time (analog) signals. CWTs operate over every possible scale and translation whereas DWTs use a specific subset of scale and translation values or representation grid.
The word wavelet is due to Morlet and Grossmann in the early 1980s. They used the French word ondelette, meaning "small wave". Soon it was transferred to English by translating "onde" into "wave", giving "wavelet".
# Wavelet theory
Wavelet theory is applicable to several subjects. All wavelet transforms may be considered forms of time-frequency representation for continuous-time (analog) signals and so are related to harmonic analysis. Almost all practically useful discrete wavelet transforms use discrete-time filterbanks. These filter banks are called the wavelet and scaling coefficients in wavelets nomenclature. These filterbanks may contain either finite impulse response (FIR) or infinite impulse response (IIR) filters. The wavelets forming a CWT are subject to the uncertainty principle of Fourier analysis respective sampling theory: Given a signal with some event in it, one cannot assign simultaneously an exact time and frequency resp. scale to that event. The product of the uncertainties of time and frequency resp. scale has a lower bound. Thus, in the scaleogram of a continuous wavelet transform of this signal, such an event marks an entire region in the time-scale plane, instead of just one point. This is related to Heisenberg's uncertainty principle of quantum physics and has a similar derivation. Also, discrete wavelet bases may be considered in the context of other forms of the uncertainty principle.
Wavelet transforms are broadly divided into three classes: continuous, discretised and multiresolution-based.
## Continuous wavelet transforms (Continuous Shift & Scale Parameters)
In continuous wavelet transforms, a given signal of finite energy is projected on a continuous family of frequency bands (or similar subspaces of the Lp function space L^2(\R)).
For instance the signal may be represented on every frequency band of the form for all positive frequencies f>0. Then, the original signal can be reconstructed by a suitable integration over all the resulting frequency components.
The frequency bands or subspaces (sub-bands) are scaled versions of a subspace at scale 1. This subspace in turn is in most situations generated by the shifts of one generating function \psi \in L^2(\R), the mother wavelet. For the example of the scale one frequency band this function is
with the (normalized) sinc function. Other example mother wavelets are:
The subspace of scale a or frequency band is generated by the functions (sometimes called child wavelets)
where a is positive and defines the scale and b is any real number and defines the shift. The pair (a,b) defines a point in the right halfplane \R_+\times \R.
The projection of a function x onto the subspace of scale a then has the form
with wavelet coefficients
See a list of some Continuous wavelets.
For the analysis of the signal x, one can assemble the wavelet coefficients into a scaleogram of the signal.
## Discrete wavelet transforms (Discrete Shift & Scale parameters)
It is computationally impossible to analyze a signal using all wavelet coefficients, so one may wonder if it is sufficient to pick a discrete subset of the upper halfplane to be able to reconstruct a signal from the corresponding wavelet coefficients. One such system is the affine system for some real parameters a>1, b>0. The corresponding discrete subset of the halfplane consists of all the points (a^m, n\,a^m b) with integers m,n\in\Z. The corresponding baby wavelets are now given as
A sufficient condition for the reconstruction of any signal x of finite energy by the formula
is that the functions \{\psi_{m,n}:m,n\in\Z\} form a tight frame of L^2(\R).
## Multiresolution-based discrete wavelet transforms
In any discretised wavelet transform, there are only a finite number of wavelet coefficients for each bounded rectangular region in the upper halfplane. Still, each coefficient requires the evaluation of an integral. To avoid this numerical complexity, one needs one auxiliary function, the father wavelet \phi\in L^2(\R). Further, one has to restrict a to be an integer. A typical choice is a=2 and b=1. The most famous pair of father and mother wavelets is the Daubechies 4 tap wavelet.
From the mother and father wavelets one constructs the subspaces
and
From these one requires that the sequence
forms a multiresolution analysis of L^2(\R) and that the subspaces \dots,W_1,W_0,W_{-1},\dots\dots are the orthogonal "differences" of the above sequence, that is,
W_m is the orthogonal complement of V_m inside the subspace V_{m-1}. In analogy to the sampling theorem one may conclude that the space V_m with sampling distance 2^m more or less covers the frequency baseband from 0 to 2^{-m-1}. As orthogonal complement, W_m roughly covers the band .
From those inclusions and orthogonality relations follows the existence of sequences h=\{h_n\}_{n\in\Z} and
g=\{g_n\}_{n\in\Z} that satisfy the identities
and
The second identity of the first pair is a refinement equation for the father wavelet \phi.
Both pairs of identities form the basis for the algorithm of the fast wavelet transform.
# Mother wavelet
For practical applications, and for efficiency reasons, one prefers continuously differentiable functions with compact support as mother (prototype) wavelet (functions). However, to satisfy analytical requirements (in the continuous WT) and in general for theoretical reasons, one chooses the wavelet functions from a subspace of the space L^1(\R)\cap L^2(\R). This is the space of measurable functions that are absolutely and square integrable:
Being in this space ensures that one can formulate the conditions of zero mean and square norm one:
For \psi to be a wavelet for the continuous wavelet transform (see there for exact statement), the mother wavelet must satisfy an admissibility criterion (loosely speaking, a kind of half-differentiability) in order to get a stably invertible transform.
For the discrete wavelet transform, one needs at least the condition that the wavelet series is a representation of the identity in the space L^2(\R). Most constructions of discrete
WT make use of the multiresolution analysis, which defines the wavelet by a scaling function. This scaling function itself is solution to a functional equation.
In most situations it is useful to restrict \psi to be a continuous function with a higher number M of vanishing moments, i.e. for all integer m<M
Some example mother wavelets are:
The mother wavelet is scaled (or dilated) by a factor of a and translated (or shifted) by a factor of b to give (under Morlet's original formulation):
For the continuous WT, the pair (a,b) varies over the full half-plane \R_+\times\R; for the discrete WT this pair varies over a discrete subset of it, which is also called affine group.
These functions are often incorrectly referred to as the basis functions of the (continuous) transform. In fact, as in the continuous Fourier transform, there is no basis in the continuous wavelet transform. Time-frequency interpretation uses a subtly different formulation (after Delprat).
# Comparisons with Fourier Transform (Continuous-Time)
The wavelet transform is often compared with the Fourier transform, in which signals are represented as a sum of sinusoids. The main difference is that wavelets are localized in both time and frequency whereas the standard Fourier transform is only localized in frequency. The Short-time Fourier transform (STFT) is also time and frequency localized but there are issues with the frequency time resolution and wavelets often give a better signal representation using Multiresolution analysis.
The discrete wavelet transform is also less computationally complex, taking O(N) time as compared to O(N log N) for the fast Fourier transform. This computational advantage is not inherent to the transform, but reflects the choice of a logarithmic division of frequency, in contrast to the equally spaced frequency divisions of the FFT.
# Definition of a wavelet
There are a number of ways of defining a wavelet (or a wavelet family).
## Scaling filter
The wavelet is entirely defined by the scaling filter - a low-pass finite impulse response (FIR) filter of length 2N and sum 1. In biorthogonal wavelets, separate decomposition and reconstruction filters are defined.
For analysis the high pass filter is calculated as the quadrature mirror filter of the low pass, and reconstruction filters the time reverse of the decomposition.
Daubechies and Symlet wavelets can be defined by the scaling filter.
## Scaling function
Wavelets are defined by the wavelet function \psi (t) (i.e. the mother wavelet) and scaling function \phi (t) (also called father wavelet) in the time domain.
The wavelet function is in effect a band-pass filter and scaling it for each level halves its bandwidth. This creates the problem that in order to cover the entire spectrum, an infinite number of levels would be required. The scaling function filters the lowest level of the transform and ensures all the spectrum is covered. See for a detailed explanation.
For a wavelet with compact support, \phi (t) can be considered finite in length and is equivalent to the scaling filter g.
Meyer wavelets can be defined by scaling functions
## Wavelet function
The wavelet only has a time domain representation as the wavelet function \psi (t).
For instance, Mexican hat wavelets can be defined by a wavelet function.
See a list of a few Continuous wavelets.
# Applications of Discrete Wavelet Transform
Generally, an approximation to DWT is used for data compression if signal is already sampled, and the CWT for signal analysis. Thus, DWT approximation is commonly used in engineering and computer science, and the CWT in scientific research.
Wavelet transforms are now being adopted for a vast number of applications, often replacing the conventional Fourier Transform. Many areas of physics have seen this paradigm shift, including molecular dynamics, ab initio calculations, astrophysics, density-matrix localisation, seismic geophysics, optics, turbulence and quantum mechanics. This change has also occurred in image processing, blood-pressure, heart-rate and ECG analyses, DNA analysis, protein analysis, climatology, general signal processing, speech recognition, computer graphics and multifractal analysis. In computer vision and image processing, the notion of scale-space representation and Gaussian derivative operators is regarded as a canonical multi-scale representation.
One use of wavelet approximation is in data compression. Like some other transforms, wavelet transforms can be used to transform data, then encode the transformed data, resulting in effective compression. For example, JPEG 2000 is an image compression standard that uses biorthogonal wavelets. This means that although the frame is overcomplete, it is a tight frame (see types of Frame of a vector space), and the same frame functions (except for conjugation in the case of complex wavelets) are used for both analysis and synthesis, i.e., in both the forward and inverse transform. For details see wavelet compression.
A related use is that of smoothing/denoising data based on wavelet coefficient thresholding, also called wavelet shrinkage. By adaptively thresholding the wavelet coefficients that correspond to undesired frequency components smoothing and/or denoising operations can be performed.
# History
The development of wavelets can be linked to several separate trains of thought, starting with Haar's work in the early 20th century. Notable contributions to wavelet theory can be attributed to Zweig’s discovery of the continuous wavelet transform in 1975 (originally called the cochlear transform and discovered while studying the reaction of the ear to sound), Pierre Goupillaud, Grossmann and Morlet's formulation of what is now known as the CWT (1982), Jan-Olov Strömberg's early work on discrete wavelets (1983), Daubechies' orthogonal wavelets with compact support (1988), Mallat's multiresolution framework (1989), Nathalie Delprat's time-frequency interpretation of the CWT (1991), Newland's Harmonic wavelet transform (1993) and many others since.
## Timeline
- First wavelet (Haar wavelet) by Alfred Haar (1909)
- Since the 1950s: George Zweig, Jean Morlet, Alex Grossmann
- Since the 1980s: Yves Meyer, Stéphane Mallat, Ingrid Daubechies, Ronald Coifman, Victor Wickerhauser,
# Wavelet Transforms
There are a large number of wavelet transforms each suitable for different applications. For a full list see list of wavelet-related transforms but the common ones are listed below:
- Continuous wavelet transform (CWT)
- Discrete wavelet transform (DWT)
- Fast wavelet transform (FWT)
- Lifting scheme
- Wavelet packet decomposition (WPD)
- Stationary wavelet transform (SWT)
# Generalized Transforms
There are a number of generalized transforms of which the wavelet transform is a special case. For example, Joseph Segman introduced scale into the Heisenberg group, giving rise to a continuous transform space that is a function of time, scale, and frequency. The CWT is a two-dimensional slice through the resulting 3d time-scale-frequency volume.
Another example of a generalized transform is the chirplet transform in which the CWT is also a two dimensional slice through the chirplet transform.
An important application area for generalized transforms involves systems in which high frequency resolution is crucial. For example, darkfield electron optical transforms intermediate between direct and reciprocal space have been widely used in the harmonic analysis of atom clustering, i.e. in the study of crystals and crystal defects. Now that transmission electron microscopes are capable of providing digital images with picometer-scale information on atomic periodicity in nanostructure of all sorts, the range of pattern recognition and strain/metrology applications for intermediate transforms with high frequency resolution (like brushlets and ridgelets) is growing rapidly.
# List of wavelets
## Discrete wavelets
- Beylkin (18)
- BNC wavelets
- Coiflet (6, 12, 18, 24, 30)
- Cohen-Daubechies-Feauveau wavelet (Sometimes referred to as CDF N/P or Daubechies biorthogonal wavelets)
- Daubechies wavelet (2, 4, 6, 8, 10, 12, 14, 16, 18, 20)
- Binomial-QMF
- Haar wavelet
- Mathieu wavelet
- Legendre wavelet
- Villasenor wavelet
- Symlet
## Continuous wavelets
### Real valued
- Beta wavelet
- Hermitian wavelet
- Hermitian hat wavelet
- Mexican hat wavelet
- Shannon wavelet
### Complex valued
- Complex mexican hat wavelet
- Morlet wavelet
- Shannon wavelet
- Modified Morlet wavelet | Wavelet
A wavelet is a kind of mathematical function used to divide a given function or continuous-time signal into different frequency components and study each component with a resolution that matches its scale. A wavelet transform is the representation of a function by wavelets. The wavelets are scaled and translated copies (known as "daughter wavelets") of a finite-length or fast-decaying oscillating waveform (known as the "mother wavelet"). Wavelet transforms have advantages over traditional Fourier transforms for representing functions that have discontinuities and sharp peaks, and for accurately deconstructing and reconstructing finite, non-periodic and/or non-stationary signals.
In formal terms, this representation is a wavelet series representation of a square-integrable function with respect to either a complete, orthonormal set of basis functions, or an overcomplete set of Frame of a vector space (also known as a Riesz basis), for the Hilbert space of square integrable functions.
Wavelet transforms are classified into discrete wavelet transforms (DWTs) and continuous wavelet transforms (CWTs). Note that both DWT and CWT are of continuous-time (analog) transforms. They can be used to represent continuous-time (analog) signals. CWTs operate over every possible scale and translation whereas DWTs use a specific subset of scale and translation values or representation grid.
Template:Wiktionarypar
The word wavelet is due to Morlet and Grossmann in the early 1980s. They used the French word ondelette, meaning "small wave". Soon it was transferred to English by translating "onde" into "wave", giving "wavelet".
# Wavelet theory
Wavelet theory is applicable to several subjects. All wavelet transforms may be considered forms of time-frequency representation for continuous-time (analog) signals and so are related to harmonic analysis. Almost all practically useful discrete wavelet transforms use discrete-time filterbanks. These filter banks are called the wavelet and scaling coefficients in wavelets nomenclature. These filterbanks may contain either finite impulse response (FIR) or infinite impulse response (IIR) filters. The wavelets forming a CWT are subject to the uncertainty principle of Fourier analysis respective sampling theory: Given a signal with some event in it, one cannot assign simultaneously an exact time and frequency resp. scale to that event. The product of the uncertainties of time and frequency resp. scale has a lower bound. Thus, in the scaleogram of a continuous wavelet transform of this signal, such an event marks an entire region in the time-scale plane, instead of just one point. This is related to Heisenberg's uncertainty principle of quantum physics and has a similar derivation. Also, discrete wavelet bases may be considered in the context of other forms of the uncertainty principle.
Wavelet transforms are broadly divided into three classes: continuous, discretised and multiresolution-based.
## Continuous wavelet transforms (Continuous Shift & Scale Parameters)
In continuous wavelet transforms, a given signal of finite energy is projected on a continuous family of frequency bands (or similar subspaces of the Lp function space <math>L^2(\R)</math>).
For instance the signal may be represented on every frequency band of the form <math>[f,2f]</math> for all positive frequencies f>0. Then, the original signal can be reconstructed by a suitable integration over all the resulting frequency components.
The frequency bands or subspaces (sub-bands) are scaled versions of a subspace at scale 1. This subspace in turn is in most situations generated by the shifts of one generating function <math>\psi \in L^2(\R)</math>, the mother wavelet. For the example of the scale one frequency band <math>[1,2]</math> this function is
with the (normalized) sinc function. Other example mother wavelets are:
The subspace of scale a or frequency band <math>[1/a,\,2/a]</math> is generated by the functions (sometimes called child wavelets)
where a is positive and defines the scale and b is any real number and defines the shift. The pair (a,b) defines a point in the right halfplane <math>\R_+\times \R</math>.
The projection of a function x onto the subspace of scale a then has the form
with wavelet coefficients
See a list of some Continuous wavelets.
For the analysis of the signal x, one can assemble the wavelet coefficients into a scaleogram of the signal.
## Discrete wavelet transforms (Discrete Shift & Scale parameters)
It is computationally impossible to analyze a signal using all wavelet coefficients, so one may wonder if it is sufficient to pick a discrete subset of the upper halfplane to be able to reconstruct a signal from the corresponding wavelet coefficients. One such system is the affine system for some real parameters a>1, b>0. The corresponding discrete subset of the halfplane consists of all the points <math>(a^m, n\,a^m b)</math> with integers <math>m,n\in\Z</math>. The corresponding baby wavelets are now given as
A sufficient condition for the reconstruction of any signal x of finite energy by the formula
is that the functions <math>\{\psi_{m,n}:m,n\in\Z\}</math> form a tight frame of <math>L^2(\R)</math>.
## Multiresolution-based discrete wavelet transforms
In any discretised wavelet transform, there are only a finite number of wavelet coefficients for each bounded rectangular region in the upper halfplane. Still, each coefficient requires the evaluation of an integral. To avoid this numerical complexity, one needs one auxiliary function, the father wavelet <math>\phi\in L^2(\R)</math>. Further, one has to restrict a to be an integer. A typical choice is a=2 and b=1. The most famous pair of father and mother wavelets is the Daubechies 4 tap wavelet.
From the mother and father wavelets one constructs the subspaces
and
From these one requires that the sequence
forms a multiresolution analysis of <math>L^2(\R)</math> and that the subspaces <math>\dots,W_1,W_0,W_{-1},\dots\dots</math> are the orthogonal "differences" of the above sequence, that is,
<math>W_m</math> is the orthogonal complement of <math>V_m</math> inside the subspace <math>V_{m-1}</math>. In analogy to the sampling theorem one may conclude that the space <math>V_m</math> with sampling distance <math>2^m</math> more or less covers the frequency baseband from 0 to <math>2^{-m-1}</math>. As orthogonal complement, <math>W_m</math> roughly covers the band <math>[2^{-m-1},2^{-m}]</math>.
From those inclusions and orthogonality relations follows the existence of sequences <math>h=\{h_n\}_{n\in\Z}</math> and
<math>g=\{g_n\}_{n\in\Z}</math> that satisfy the identities
and
The second identity of the first pair is a refinement equation for the father wavelet <math>\phi</math>.
Both pairs of identities form the basis for the algorithm of the fast wavelet transform.
# Mother wavelet
For practical applications, and for efficiency reasons, one prefers continuously differentiable functions with compact support as mother (prototype) wavelet (functions). However, to satisfy analytical requirements (in the continuous WT) and in general for theoretical reasons, one chooses the wavelet functions from a subspace of the space <math>L^1(\R)\cap L^2(\R)</math>. This is the space of measurable functions that are absolutely and square integrable:
Being in this space ensures that one can formulate the conditions of zero mean and square norm one:
For <math>\psi</math> to be a wavelet for the continuous wavelet transform (see there for exact statement), the mother wavelet must satisfy an admissibility criterion (loosely speaking, a kind of half-differentiability) in order to get a stably invertible transform.
For the discrete wavelet transform, one needs at least the condition that the wavelet series is a representation of the identity in the space <math>L^2(\R)</math>. Most constructions of discrete
WT make use of the multiresolution analysis, which defines the wavelet by a scaling function. This scaling function itself is solution to a functional equation.
In most situations it is useful to restrict <math>\psi</math> to be a continuous function with a higher number M of vanishing moments, i.e. for all integer m<M
Some example mother wavelets are:
The mother wavelet is scaled (or dilated) by a factor of <math>a</math> and translated (or shifted) by a factor of <math>b</math> to give (under Morlet's original formulation):
For the continuous WT, the pair (a,b) varies over the full half-plane <math>\R_+\times\R</math>; for the discrete WT this pair varies over a discrete subset of it, which is also called affine group.
These functions are often incorrectly referred to as the basis functions of the (continuous) transform. In fact, as in the continuous Fourier transform, there is no basis in the continuous wavelet transform. Time-frequency interpretation uses a subtly different formulation (after Delprat).
# Comparisons with Fourier Transform (Continuous-Time)
The wavelet transform is often compared with the Fourier transform, in which signals are represented as a sum of sinusoids. The main difference is that wavelets are localized in both time and frequency whereas the standard Fourier transform is only localized in frequency. The Short-time Fourier transform (STFT) is also time and frequency localized but there are issues with the frequency time resolution and wavelets often give a better signal representation using Multiresolution analysis.
The discrete wavelet transform is also less computationally complex, taking O(N) time as compared to O(N log N) for the fast Fourier transform. This computational advantage is not inherent to the transform, but reflects the choice of a logarithmic division of frequency, in contrast to the equally spaced frequency divisions of the FFT.
# Definition of a wavelet
There are a number of ways of defining a wavelet (or a wavelet family).
## Scaling filter
The wavelet is entirely defined by the scaling filter - a low-pass finite impulse response (FIR) filter of length 2N and sum 1. In biorthogonal wavelets, separate decomposition and reconstruction filters are defined.
For analysis the high pass filter is calculated as the quadrature mirror filter of the low pass, and reconstruction filters the time reverse of the decomposition.
Daubechies and Symlet wavelets can be defined by the scaling filter.
## Scaling function
Wavelets are defined by the wavelet function <math>\psi (t)</math> (i.e. the mother wavelet) and scaling function <math>\phi (t)</math> (also called father wavelet) in the time domain.
The wavelet function is in effect a band-pass filter and scaling it for each level halves its bandwidth. This creates the problem that in order to cover the entire spectrum, an infinite number of levels would be required. The scaling function filters the lowest level of the transform and ensures all the spectrum is covered. See [1] for a detailed explanation.
For a wavelet with compact support, <math>\phi (t)</math> can be considered finite in length and is equivalent to the scaling filter g.
Meyer wavelets can be defined by scaling functions
## Wavelet function
The wavelet only has a time domain representation as the wavelet function <math>\psi (t)</math>.
For instance, Mexican hat wavelets can be defined by a wavelet function.
See a list of a few Continuous wavelets.
# Applications of Discrete Wavelet Transform
Generally, an approximation to DWT is used for data compression if signal is already sampled, and the CWT for signal analysis. Thus, DWT approximation is commonly used in engineering and computer science, and the CWT in scientific research.
Wavelet transforms are now being adopted for a vast number of applications, often replacing the conventional Fourier Transform. Many areas of physics have seen this paradigm shift, including molecular dynamics, ab initio calculations, astrophysics, density-matrix localisation, seismic geophysics, optics, turbulence and quantum mechanics. This change has also occurred in image processing, blood-pressure, heart-rate and ECG analyses, DNA analysis, protein analysis, climatology, general signal processing, speech recognition, computer graphics and multifractal analysis. In computer vision and image processing, the notion of scale-space representation and Gaussian derivative operators is regarded as a canonical multi-scale representation.
One use of wavelet approximation is in data compression. Like some other transforms, wavelet transforms can be used to transform data, then encode the transformed data, resulting in effective compression. For example, JPEG 2000 is an image compression standard that uses biorthogonal wavelets. This means that although the frame is overcomplete, it is a tight frame (see types of Frame of a vector space), and the same frame functions (except for conjugation in the case of complex wavelets) are used for both analysis and synthesis, i.e., in both the forward and inverse transform. For details see wavelet compression.
A related use is that of smoothing/denoising data based on wavelet coefficient thresholding, also called wavelet shrinkage. By adaptively thresholding the wavelet coefficients that correspond to undesired frequency components smoothing and/or denoising operations can be performed.
# History
The development of wavelets can be linked to several separate trains of thought, starting with Haar's work in the early 20th century. Notable contributions to wavelet theory can be attributed to Zweig’s discovery of the continuous wavelet transform in 1975 (originally called the cochlear transform and discovered while studying the reaction of the ear to sound)[1], Pierre Goupillaud, Grossmann and Morlet's formulation of what is now known as the CWT (1982), Jan-Olov Strömberg's early work on discrete wavelets (1983), Daubechies' orthogonal wavelets with compact support (1988), Mallat's multiresolution framework (1989), Nathalie Delprat's time-frequency interpretation of the CWT (1991), Newland's Harmonic wavelet transform (1993) and many others since.
## Timeline
- First wavelet (Haar wavelet) by Alfred Haar (1909)
- Since the 1950s: George Zweig, Jean Morlet, Alex Grossmann
- Since the 1980s: Yves Meyer, Stéphane Mallat, Ingrid Daubechies, Ronald Coifman, Victor Wickerhauser,
# Wavelet Transforms
There are a large number of wavelet transforms each suitable for different applications. For a full list see list of wavelet-related transforms but the common ones are listed below:
- Continuous wavelet transform (CWT)
- Discrete wavelet transform (DWT)
- Fast wavelet transform (FWT)
- Lifting scheme
- Wavelet packet decomposition (WPD)
- Stationary wavelet transform (SWT)
# Generalized Transforms
There are a number of generalized transforms of which the wavelet transform is a special case. For example, Joseph Segman introduced scale into the Heisenberg group, giving rise to a continuous transform space that is a function of time, scale, and frequency. The CWT is a two-dimensional slice through the resulting 3d time-scale-frequency volume.
Another example of a generalized transform is the chirplet transform in which the CWT is also a two dimensional slice through the chirplet transform.
An important application area for generalized transforms involves systems in which high frequency resolution is crucial. For example, darkfield electron optical transforms intermediate between direct and reciprocal space have been widely used in the harmonic analysis of atom clustering, i.e. in the study of crystals and crystal defects[2]. Now that transmission electron microscopes are capable of providing digital images with picometer-scale information on atomic periodicity in nanostructure of all sorts, the range of pattern recognition[3] and strain[4]/metrology[5] applications for intermediate transforms with high frequency resolution (like brushlets[6] and ridgelets[7]) is growing rapidly.
# List of wavelets
## Discrete wavelets
- Beylkin (18)
- BNC wavelets
- Coiflet (6, 12, 18, 24, 30)
- Cohen-Daubechies-Feauveau wavelet (Sometimes referred to as CDF N/P or Daubechies biorthogonal wavelets)
- Daubechies wavelet (2, 4, 6, 8, 10, 12, 14, 16, 18, 20)
- Binomial-QMF
- Haar wavelet
- Mathieu wavelet
- Legendre wavelet
- Villasenor wavelet
- Symlet
## Continuous wavelets
### Real valued
- Beta wavelet
- Hermitian wavelet
- Hermitian hat wavelet
- Mexican hat wavelet
- Shannon wavelet
### Complex valued
- Complex mexican hat wavelet
- Morlet wavelet
- Shannon wavelet
- Modified Morlet wavelet | https://www.wikidoc.org/index.php/Wavelet | |
dbe6cb066a749f6d6f439639bd5229345c98e41f | wikidoc | Winpepi | Winpepi
# WINPEPI
WinPepi is a freeware package of statistical programs for epidemiologists, comprising seven programs with over 100 modules. WinPepi is not a complete compendium of statistical routines for epidemiologists. but it provides a very wide range of procedures, including those most commonly used and many that are not easy to find elsewhere. This has repeatedly led reviewers to use a "Swiss army knife" analogy. Each program has a comprehensive fully-referenced manual.
WinPepi had its origins in 1983 in a book of programs for hand-held calculators, which in 1993 developed into a set of DOS-based computer programs that came to be called Pepi (an acronym for "Programs for EPIdemiologists") and evolved, after its fourth version in 2001, into WinPepi (Pepi-for-Windows). WinPepi is still a work in progress, and new expanded versions are issued at frequent intervals.
The programs are notable for their user-friendliness. A portal provides immediate access to all the programs and manuals, and to an alphabetical index that pinpoints the programs and modules to be used for specific purposes. Menus, buttons, on-screen instructions, help screens, pop-up hints, and built-in error traps make the programs easy to use.
WinPepi does not provide data management facilities. With some exceptions, it requires the entry (at the keyboard or by pasting) of data that have already been counted or summarized. | Winpepi
# WINPEPI
WinPepi is a freeware package of statistical programs for epidemiologists, comprising seven programs with over 100 modules. WinPepi is not a complete compendium of statistical routines for epidemiologists. but it provides a very wide range of procedures, including those most commonly used and many that are not easy to find elsewhere. This has repeatedly led reviewers to use a "Swiss army knife" analogy. Each program has a comprehensive fully-referenced manual.
WinPepi had its origins in 1983 in a book of programs for hand-held calculators,[1] which in 1993 developed into a set of DOS-based computer programs[2] that came to be called Pepi (an acronym for "Programs for EPIdemiologists") and evolved, after its fourth version in 2001,[3] into WinPepi (Pepi-for-Windows).[4] WinPepi is still a work in progress, and new expanded versions are issued at frequent intervals.
The programs are notable for their user-friendliness. A portal provides immediate access to all the programs and manuals, and to an alphabetical index that pinpoints the programs and modules to be used for specific purposes. Menus, buttons, on-screen instructions, help screens, pop-up hints, and built-in error traps make the programs easy to use.
WinPepi does not provide data management facilities. With some exceptions, it requires the entry (at the keyboard or by pasting) of data that have already been counted or summarized. | https://www.wikidoc.org/index.php/Winpepi | |
5c50308fa6894653073f4b8fae263ecd621daf3a | wikidoc | Wrinkle | Wrinkle
# Overview
A wrinkle is a ridge or crease of a surface. It usually refers to folds on fabric or clothes, or on the skin of an organism; the folds are generally random and do not exhibit any repeating pattern. In skin or other foldable material a wrinkle or fold may be permanent if the material is folded the same way each time.
Skin wrinkles typically appear as a result of aging processes such as glycation or, temporarily, as the result of prolonged (more than a few minutes) immersion in water. Wrinkling in skin is caused by habitual facial expressions, aging, sun damage, smoking, poor hydration, and various other factors.
# Aging wrinkles
Treatments and products (including anti-aging creams) promising to reduce, remove, or prevent age-related wrinkles are big business in many industrialized countries. Despite great demand, most such products and treatments have not been proven to give lasting or major positive effects. Stretching the skin via a face lift will remove some wrinkles.
## Retinoic Acid
## Botox
## Sculptra
## Research into Elastin and Collagen formation and degradation
# Prune fingers
The wrinkles that occur in skin after prolonged exposure to water are sometimes referred to as prune fingers or water aging. This is a temporary skin condition where the skin on the palms of the hand or feet becomes wrinkly. It is caused when the keratin-laden epithelial skin is immersed in water. The skin expands and the resultant larger surface area forces it to wrinkle. Usually the tips of the fingers and toes are the first to wrinkle because of a thicker layer of keratin and an absence of hairs which secrete the protective oil called sebum. Wrinkled fingers often occur after taking a shower or bath and last up to fifteen minutes afterwards, until the water has evaporated or is absorbed into the body.
Prune fingers is named for the skins' resemblance to the wrinkled, rough surface of a prune.
# Animals with wrinkles
Examples of wrinkles can be found in various animal species that grow loose, excess skin, particularly when they are young. Several breeds of dog, such as the Pug and the Shar Pei, have been bred to exaggerate this trait. In dogs bred for fighting, this is the result of selection for loose skin, which confers a protective advantage. Wrinkles are also associated with neoteny (cuteness), as they are a trait associated with juvenile animals.
# Fabric wrinkles
Fabric wrinkles occur as a result of cloth being bunched or folded unevenly. Wrinkled clothing is often undesirable in situations such as job interviews, or formal social events. There are products such as irons and fabric sprays to remove wrinkles from cloth. Some more modern fabrics have been engineered to be wrinkle-free or wrinkle-resistant by incorporating water-resistant polymers. | Wrinkle
# Overview
A wrinkle is a ridge or crease of a surface. It usually refers to folds on fabric or clothes, or on the skin of an organism; the folds are generally random and do not exhibit any repeating pattern. In skin or other foldable material a wrinkle or fold may be permanent if the material is folded the same way each time.
Skin wrinkles typically appear as a result of aging processes such as glycation or, temporarily, as the result of prolonged (more than a few minutes) immersion in water. Wrinkling in skin is caused by habitual facial expressions, aging, sun damage, smoking, poor hydration, and various other factors. [1]
# Aging wrinkles
Treatments and products (including anti-aging creams) promising to reduce, remove, or prevent age-related wrinkles are big business in many industrialized countries. Despite great demand, most such products and treatments have not been proven to give lasting or major positive effects. Stretching the skin via a face lift will remove some wrinkles.
## Retinoic Acid
## Botox
## Sculptra
## Research into Elastin and Collagen formation and degradation
# Prune fingers
The wrinkles that occur in skin after prolonged exposure to water are sometimes referred to as prune fingers or water aging. This is a temporary skin condition where the skin on the palms of the hand or feet becomes wrinkly. It is caused when the keratin-laden epithelial skin is immersed in water[1]. The skin expands and the resultant larger surface area forces it to wrinkle. Usually the tips of the fingers and toes are the first to wrinkle because of a thicker layer of keratin and an absence of hairs which secrete the protective oil called sebum. Wrinkled fingers often occur after taking a shower or bath and last up to fifteen minutes afterwards, until the water has evaporated or is absorbed into the body.
Prune fingers is named for the skins' resemblance to the wrinkled, rough surface of a prune.
# Animals with wrinkles
Examples of wrinkles can be found in various animal species that grow loose, excess skin, particularly when they are young. Several breeds of dog, such as the Pug and the Shar Pei, have been bred to exaggerate this trait. In dogs bred for fighting, this is the result of selection for loose skin, which confers a protective advantage. Wrinkles are also associated with neoteny (cuteness), as they are a trait associated with juvenile animals.
# Fabric wrinkles
Fabric wrinkles occur as a result of cloth being bunched or folded unevenly. Wrinkled clothing is often undesirable in situations such as job interviews, or formal social events. There are products such as irons and fabric sprays to remove wrinkles from cloth. Some more modern fabrics have been engineered to be wrinkle-free or wrinkle-resistant by incorporating water-resistant polymers. | https://www.wikidoc.org/index.php/Wrinkle | |
3865f66c2e0231d28f054ab40789943e8bc5078d | wikidoc | Writing | Writing
# Overview
Writing is the representation of language in a textual medium through the use of a set of signs or symbols (known as a writing system). It is distinguished from illustration, such as cave drawing and painting, and the recording of language via a non-textual medium such as magnetic tape audio.
Writing began as a consequence of the burgeoning needs of accounting. Around the 4th millennium BC, the complexity of trade and administration outgrew the power of memory, and writing became a more dependable method of recording and presenting transactions in a permanent form (Robinson, 2003, p. 36).
# Writing as a category
Writing, more particularly, refers to two things: writing as a noun, the thing that is written; and writing as a verb, which designates the activity of writing. It refers to the inscription of characters on a medium, thereby forming words, and larger units of language, known as texts. It also refers to the creation of meaning and the information thereby generated. In that regard, linguistics (and related sciences) distinguishes between the written language and the spoken language. The significance of the medium by which meaning and information is conveyed is indicated by the distinction made in the arts and sciences. For example,
while public speaking and poetry reading are both types of speech, the former is governed by the rules of rhetoric and the latter by poetics.
A person who composes a message or story in the form of text is generally known as a writer or an author. However, more specific designations exist which are dictated by the particular nature of the text such as that of poet, essayist, novelist, playwright, journalist, and more. A person who transcribes, translates or produces text to deliver a message authored by another person is known as a scribe, typist or typesetter. A person who produces text with emphasis on the aesthetics of glyphs is known as a calligrapher or graphic designer.
Writing is also a distinctly human activity. It has been said that a monkey, randomly typing away on a typewriter (in the days when typewriters replaced the pen or plume as the preferred instrument of writing) could re-create Shakespeare-- but only if it lived long enough (this is known as the infinite monkey theorem). Such writing has been speculatively designated as coincidental. It is also speculated that extra-terrestrial beings exist who may possess knowledge of writing. The fact is that the only known writing is human writing.
# Means for recording information
Wells argues that writing has the ability to "put agreements, laws, commandments on record. It made the growth of states larger than the old city states possible. The command of the priest or king and his seal could go far beyond his sight and voice and could survive his death" (Wells in Robinson, 2003, p. 35).
## Writing systems
The major writing systems – methods of inscription – broadly fall into four categories: logographic, syllabic, alphabetic, and featural.
Another category, ideographic (symbols for ideas), has never been developed sufficiently to represent language. A sixth category, pictographic, is insufficient to represent language on its own, but often forms the core of logographies.
### Logographies
A logogram is a written character which represents a word or morpheme. The vast number of logograms needed to write language, and the many years required to learn them, are the major disadvantage of the logographic systems over alphabetic systems. However, the efficiency of reading logographic writing once it is learned is a major advantage.
No writing system is wholly logographic: all have phonetic components as well as logograms ("logosyllabic" components in the case of Chinese characters, cuneiform, and Mayan, where a glyph may stand for a morpheme, a syllable, or both; "logoconsonantal" in the case of hieroglyphs), and many have an ideographic component (Chinese "radicals", hieroglyphic "determiners"). For example, in Mayan, the glyph for "fin", pronounced "ka'", was also used to represent the syllable "ka" whenever the pronunciation of a logogram needed to be indicated, or when there was no logogram. In Chinese, about 90% of characters are compounds of a semantic (meaning) element called a radical with an existing character to indicate the pronunciation, called a phonetic. However, such phonetic elements complement the logographic elements, rather than vice versa.
The main logographic system in use today is Chinese characters, used with some modification for various languages of China, Japanese, and, to a lesser extent, Korean in South Korea. Another is the classical Yi script.
### Syllabaries
A syllabary is a set of written symbols that represent (or approximate) syllables. A glyph in a syllabary typically represents a consonant followed by a vowel, or just a vowel alone, though in some scripts more complex syllables (such as consonant-vowel-consonant, or consonant-consonant-vowel) may have dedicated glyphs. Phonetically related syllables are not so indicated in the script. For instance, the syllable "ka" may look nothing like the syllable "ki", nor will syllables with the same vowels be similar.
Syllabaries are best suited to languages with relatively simple syllable structure, such as Japanese. Other languages that use syllabic writing include the Linear B script for Mycenaean Greek; Cherokee; Ndjuka, an English-based creole language of Surinam; and the Vai script of Liberia. Most logographic systems have a strong syllabic component. Ethiopic, though technically an alphabet, has fused consonants and vowels together to the point that it's learned as if it were a syllabary.
### Alphabets
An alphabet is a small set of symbols, each of which roughly represents or historically represented a phoneme of the language. In a perfectly phonological alphabet, the phonemes and letters would correspond perfectly in two directions: a writer could predict the spelling of a word given its pronunciation, and a speaker could predict the pronunciation of a word given its spelling. As languages often evolve independently of their writing systems, and writing systems have been borrowed for languages they were not designed for, the degree to which letters of an alphabet correspond to phonemes of a language varies greatly from one language to another and even within a single language.
In most of the alphabets of the Mid-East, only consonants are indicated, or vowels may be indicated with optional diacritics. Such systems are called abjads. In most of the alphabets of India and Southeast Asia, vowels are indicated through diacritics or modification of the shape of the consonant. These are called abugidas. Some abugidas, such as Ethiopic and Cree, are learned by children as syllabaries, and so are often called "syllabics". However, unlike true syllabaries, there is not an independent glyph for each syllable.
Sometimes the term "alphabet" is restricted to systems with separate letters for consonants and vowels, such as the Latin alphabet. Because of this use, Greek is often considered to be the first alphabet.
### Featural scripts
A featural script notates the building blocks of the phonemes that make up a language. For instance, all sounds pronounced with the lips ("labial" sounds) may have some element in common. In the Latin alphabet, this is accidentally the case with the letters "b" and "p"; however, labial "m" is completely dissimilar, and the similar-looking "q" is not labial. In Korean hangul, however, all four labial consonants are based on the same basic element. However, in practice, Korean is learned by children as an ordinary alphabet, and the featural elements tend to pass unnoticed.
Another featural script is SignWriting, the most popular writing system for many sign languages, where the shapes and movements of the hands and face are represented iconically. Featural scripts are also common in fictional or invented systems, such as Tolkien's Tengwar.
### Historical significance of writing systems
Historians draw a distinction between prehistory and history, with history defined by the advent of writing. The cave paintings and petroglyphs of prehistoric peoples can be considered precursors of writing, but are not considered writing because they did not represent language directly.
Writing systems always develop and change based on the needs of the people who use them. Sometimes the shape, orientation and meaning of individual signs also changes over time. By tracing the development of a script it is possible to learn about the needs of the people who used the script as well as how it changed over time.
## Tools and materials
The many tools and writing materials used throughout history include stone tablets, clay tablets, wax tablets, vellum, parchment, paper, copperplate, styluses, quills, ink brushes, pencils, pens, and many styles of lithography. It is speculated that the Incas might have employed knotted threads known as quipu (or khipu) as a writing system.
For more information see writing implements.
# History of early writing
By definition, history begins with written records; evidence of human culture without writing is the realm of prehistory.
The evolution of writing was a process involving economic necessity in the ancient near east. Archaeologist Denise Schmandt-Besserat determined the link between previously uncategorized clay "tokens" and the first known writing, cuneiform. The clay tokens were used to represent commodities, and perhaps even units of time spent in labor, and their number and type became more complex as civilization advanced. A degree of complexity was reached when over a hundred different kinds of tokens had to be accounted for, and tokens were wrapped and fired in clay, with markings to indicate the kind of tokens inside. These markings soon replaced the tokens themselves, and the clay envelopes were demonstrably the prototype for clay writing tablets.
## Mesopotamia
The original Mesopotamian writing system was derived from this method of keeping accounts, and by the end of the 4th millennium BC, this had evolved into using a triangular-shaped stylus pressed into soft clay for recording numbers. This was gradually augmented with pictographic writing using a sharp stylus to indicate what was being counted. Round-stylus and sharp-stylus writing was gradually replaced by writing using a wedge-shaped stylus (hence the term cuneiform), at first only for logograms, but evolved to include phonetic elements by the 29th century BC. Around the 26th century BC, cuneiform began to represent syllables of spoken Sumerian. Also in that period, cuneiform writing became a general purpose writing system for logograms, syllables, and numbers, and this script was adapted to another Mesopotamian language, Akkadian, and from there to others such as Hurrian, and Hittite. Scripts similar in appearance to this writing system include those for Ugaritic and Old Persian.
## Turkmenistan
An unknown civilization in Central Asia 4,000 years ago, hundreds of years before Chinese writing developed. An excavation near Ashgabat, the capital of Turkmenistan, revealed an inscription on a piece of stone that was used as a stamp seal.
## China
In China historians have found out a lot about the early Chinese dynasties from the written documents left behind. From the Shang Dynasty most of this writing has survived on bones or bronze implements. Markings on turtle shells have been carbon-dated to around 1500 BC. Historians have found that the type of media used had an effect on what the writing was documenting and how it was used.
There have recently been discoveries of tortoise-shell carvings dating back to c. 6000 BC, but whether or not the carvings are of sufficient complexity to qualify as writing is under debate. If it is deemed to be a written language, writing in China will predate Mesopotamian cuneiform, long acknowledged as the first appearance of writing, by some 2000 years.
## Egypt
The earliest known hieroglyphic inscriptions are the Narmer Palette, dating to c.3200 BC, and several recent discoveries that may be slightly older, though the glyphs were based on a much older artistic tradition. The hieroglyphic script was logographic with phonetic adjuncts that included an effective alphabet.
Writing was very important in maintaining the Egyptian empire, and literacy was concentrated among an educated elite of scribes. Only people from certain backgrounds were allowed to train to become scribes, in the service of temple, pharaonic, and military authorities. The hieroglyph system was always difficult to learn, but in later centuries was purposely made even more so, as this preserved the scribes' status.
The world's oldest known alphabet was developed in central Egypt around 2000 BC from a hieroglyphic prototype, and over the next 500 years spread to Canaan and eventually to the rest of the world.
## Indus Valley
The Indus Valley script is a mysterious aspect of ancient Indian culture as it has not yet been deciphered. All known inscriptions are short.
## Phoenician writing system and descendants
The Phoenician writing system was adapted from the Proto-Caananite script in around the 11th century BC, which in turn borrowed ideas from Egyptian hieroglyphics. This writing system was an abjad — that is, a writing system in which only consonants are represented. This script was adapted by the Greeks, who adapted certain consonantal signs to represent their vowels. The Cumae alphabet, a variant of the early Greek alphabet gave rise to the Etruscan alphabet, and its own descendants, such as the Latin alphabet and Runes. Other descendants from the Greek alphabet include the Cyrillic alphabet, used to write Russian, among others. The Phoenician system was also adapted into the Aramaic script, from which the Hebrew script and also that of Arabic are descended.
The Tifinagh script (Berber languages) is descended from the Libyco-Berber script which is assumed to be of Phoenician origin.
## Mesoamerica
A stone slab with 3,000-year-old writing was discovered in the Mexican state of Veracruz, and is an example of the oldest script in the Western Hemisphere preceding the oldest Zapotec writing dated to about 500 BC.
Of several pre-Colombian scripts in Mesoamerica, the one that appears to have been best developed, and the only one to be deciphered, is the Maya script. The earliest inscriptions which are identifiably Maya date to the 3rd century BC, and writing was in continuous use until shortly after the arrival of the Spanish conquistadores in the 16th century AD. Maya writing used logograms complemented by a set of syllabic glyphs, somewhat similar in function to modern Japanese writing.
# Creation of text or information
## Creativity
## Author
## Writer
## Critiques
Writers sometimes search out others to evaluate or criticize their work. To this end, many writers join writing circles, often found at local libraries or bookstores. With the evolution of the Internet, writing circles have started to go online. | Writing
# Overview
Writing is the representation of language in a textual medium through the use of a set of signs or symbols (known as a writing system). It is distinguished from illustration, such as cave drawing and painting, and the recording of language via a non-textual medium such as magnetic tape audio.
Writing began as a consequence of the burgeoning needs of accounting. Around the 4th millennium BC, the complexity of trade and administration outgrew the power of memory, and writing became a more dependable method of recording and presenting transactions in a permanent form (Robinson, 2003, p. 36).
# Writing as a category
Writing, more particularly, refers to two things: writing as a noun, the thing that is written; and writing as a verb, which designates the activity of writing. It refers to the inscription of characters on a medium, thereby forming words, and larger units of language, known as texts. It also refers to the creation of meaning and the information thereby generated. In that regard, linguistics (and related sciences) distinguishes between the written language and the spoken language. The significance of the medium by which meaning and information is conveyed is indicated by the distinction made in the arts and sciences. For example,
while public speaking and poetry reading are both types of speech, the former is governed by the rules of rhetoric and the latter by poetics.
A person who composes a message or story in the form of text is generally known as a writer or an author. However, more specific designations exist which are dictated by the particular nature of the text such as that of poet, essayist, novelist, playwright, journalist, and more. A person who transcribes, translates or produces text to deliver a message authored by another person is known as a scribe, typist or typesetter. A person who produces text with emphasis on the aesthetics of glyphs is known as a calligrapher or graphic designer.
Writing is also a distinctly human activity. It has been said that a monkey, randomly typing away on a typewriter (in the days when typewriters replaced the pen or plume as the preferred instrument of writing) could re-create Shakespeare-- but only if it lived long enough (this is known as the infinite monkey theorem). Such writing has been speculatively designated as coincidental. It is also speculated that extra-terrestrial beings exist who may possess knowledge of writing. The fact is that the only known writing is human writing.
# Means for recording information
Wells argues that writing has the ability to "put agreements, laws, commandments on record. It made the growth of states larger than the old city states possible. The command of the priest or king and his seal could go far beyond his sight and voice and could survive his death" (Wells in Robinson, 2003, p. 35).
## Writing systems
The major writing systems – methods of inscription – broadly fall into four categories: logographic, syllabic, alphabetic, and featural.
Another category, ideographic (symbols for ideas), has never been developed sufficiently to represent language. A sixth category, pictographic, is insufficient to represent language on its own, but often forms the core of logographies.
### Logographies
A logogram is a written character which represents a word or morpheme. The vast number of logograms needed to write language, and the many years required to learn them, are the major disadvantage of the logographic systems over alphabetic systems. However, the efficiency of reading logographic writing once it is learned is a major advantage.
No writing system is wholly logographic: all have phonetic components as well as logograms ("logosyllabic" components in the case of Chinese characters, cuneiform, and Mayan, where a glyph may stand for a morpheme, a syllable, or both; "logoconsonantal" in the case of hieroglyphs), and many have an ideographic component (Chinese "radicals", hieroglyphic "determiners"). For example, in Mayan, the glyph for "fin", pronounced "ka'", was also used to represent the syllable "ka" whenever the pronunciation of a logogram needed to be indicated, or when there was no logogram. In Chinese, about 90% of characters are compounds of a semantic (meaning) element called a radical with an existing character to indicate the pronunciation, called a phonetic. However, such phonetic elements complement the logographic elements, rather than vice versa.
The main logographic system in use today is Chinese characters, used with some modification for various languages of China, Japanese, and, to a lesser extent, Korean in South Korea. Another is the classical Yi script.
### Syllabaries
A syllabary is a set of written symbols that represent (or approximate) syllables. A glyph in a syllabary typically represents a consonant followed by a vowel, or just a vowel alone, though in some scripts more complex syllables (such as consonant-vowel-consonant, or consonant-consonant-vowel) may have dedicated glyphs. Phonetically related syllables are not so indicated in the script. For instance, the syllable "ka" may look nothing like the syllable "ki", nor will syllables with the same vowels be similar.
Syllabaries are best suited to languages with relatively simple syllable structure, such as Japanese. Other languages that use syllabic writing include the Linear B script for Mycenaean Greek; Cherokee; Ndjuka, an English-based creole language of Surinam; and the Vai script of Liberia. Most logographic systems have a strong syllabic component. Ethiopic, though technically an alphabet, has fused consonants and vowels together to the point that it's learned as if it were a syllabary.
### Alphabets
An alphabet is a small set of symbols, each of which roughly represents or historically represented a phoneme of the language. In a perfectly phonological alphabet, the phonemes and letters would correspond perfectly in two directions: a writer could predict the spelling of a word given its pronunciation, and a speaker could predict the pronunciation of a word given its spelling. As languages often evolve independently of their writing systems, and writing systems have been borrowed for languages they were not designed for, the degree to which letters of an alphabet correspond to phonemes of a language varies greatly from one language to another and even within a single language.
In most of the alphabets of the Mid-East, only consonants are indicated, or vowels may be indicated with optional diacritics. Such systems are called abjads. In most of the alphabets of India and Southeast Asia, vowels are indicated through diacritics or modification of the shape of the consonant. These are called abugidas. Some abugidas, such as Ethiopic and Cree, are learned by children as syllabaries, and so are often called "syllabics". However, unlike true syllabaries, there is not an independent glyph for each syllable.
Sometimes the term "alphabet" is restricted to systems with separate letters for consonants and vowels, such as the Latin alphabet. Because of this use, Greek is often considered to be the first alphabet.
### Featural scripts
A featural script notates the building blocks of the phonemes that make up a language. For instance, all sounds pronounced with the lips ("labial" sounds) may have some element in common. In the Latin alphabet, this is accidentally the case with the letters "b" and "p"; however, labial "m" is completely dissimilar, and the similar-looking "q" is not labial. In Korean hangul, however, all four labial consonants are based on the same basic element. However, in practice, Korean is learned by children as an ordinary alphabet, and the featural elements tend to pass unnoticed.
Another featural script is SignWriting, the most popular writing system for many sign languages, where the shapes and movements of the hands and face are represented iconically. Featural scripts are also common in fictional or invented systems, such as Tolkien's Tengwar.
### Historical significance of writing systems
Historians draw a distinction between prehistory and history, with history defined by the advent of writing. The cave paintings and petroglyphs of prehistoric peoples can be considered precursors of writing, but are not considered writing because they did not represent language directly.
Writing systems always develop and change based on the needs of the people who use them. Sometimes the shape, orientation and meaning of individual signs also changes over time. By tracing the development of a script it is possible to learn about the needs of the people who used the script as well as how it changed over time.
## Tools and materials
Template:Unreferencedsection
The many tools and writing materials used throughout history include stone tablets, clay tablets, wax tablets, vellum, parchment, paper, copperplate, styluses, quills, ink brushes, pencils, pens, and many styles of lithography. It is speculated that the Incas might have employed knotted threads known as quipu (or khipu) as a writing system.
For more information see writing implements.
# History of early writing
By definition, history begins with written records; evidence of human culture without writing is the realm of prehistory.
The evolution of writing was a process involving economic necessity in the ancient near east. Archaeologist Denise Schmandt-Besserat determined the link between previously uncategorized clay "tokens" and the first known writing, cuneiform.[1] The clay tokens were used to represent commodities, and perhaps even units of time spent in labor, and their number and type became more complex as civilization advanced. A degree of complexity was reached when over a hundred different kinds of tokens had to be accounted for, and tokens were wrapped and fired in clay, with markings to indicate the kind of tokens inside. These markings soon replaced the tokens themselves, and the clay envelopes were demonstrably the prototype for clay writing tablets.[1]
## Mesopotamia
The original Mesopotamian writing system was derived from this method of keeping accounts, and by the end of the 4th millennium BC,[2] this had evolved into using a triangular-shaped stylus pressed into soft clay for recording numbers. This was gradually augmented with pictographic writing using a sharp stylus to indicate what was being counted. Round-stylus and sharp-stylus writing was gradually replaced by writing using a wedge-shaped stylus (hence the term cuneiform), at first only for logograms, but evolved to include phonetic elements by the 29th century BC. Around the 26th century BC, cuneiform began to represent syllables of spoken Sumerian. Also in that period, cuneiform writing became a general purpose writing system for logograms, syllables, and numbers, and this script was adapted to another Mesopotamian language, Akkadian, and from there to others such as Hurrian, and Hittite. Scripts similar in appearance to this writing system include those for Ugaritic and Old Persian.
## Turkmenistan
An unknown civilization in Central Asia 4,000 years ago, hundreds of years before Chinese writing developed. An excavation near Ashgabat, the capital of Turkmenistan, revealed an inscription on a piece of stone that was used as a stamp seal. [3]
## China
In China historians have found out a lot about the early Chinese dynasties from the written documents left behind. From the Shang Dynasty most of this writing has survived on bones or bronze implements. Markings on turtle shells have been carbon-dated to around 1500 BC. Historians have found that the type of media used had an effect on what the writing was documenting and how it was used.
There have recently been discoveries of tortoise-shell carvings dating back to c. 6000 BC, but whether or not the carvings are of sufficient complexity to qualify as writing is under debate.[4][5] If it is deemed to be a written language, writing in China will predate Mesopotamian cuneiform, long acknowledged as the first appearance of writing, by some 2000 years.
## Egypt
The earliest known hieroglyphic inscriptions are the Narmer Palette, dating to c.3200 BC, and several recent discoveries that may be slightly older, though the glyphs were based on a much older artistic tradition. The hieroglyphic script was logographic with phonetic adjuncts that included an effective alphabet.
Writing was very important in maintaining the Egyptian empire, and literacy was concentrated among an educated elite of scribes. Only people from certain backgrounds were allowed to train to become scribes, in the service of temple, pharaonic, and military authorities. The hieroglyph system was always difficult to learn, but in later centuries was purposely made even more so, as this preserved the scribes' status.
The world's oldest known alphabet was developed in central Egypt around 2000 BC from a hieroglyphic prototype, and over the next 500 years spread to Canaan and eventually to the rest of the world.
## Indus Valley
The Indus Valley script is a mysterious aspect of ancient Indian culture as it has not yet been deciphered. All known inscriptions are short.
## Phoenician writing system and descendants
The Phoenician writing system was adapted from the Proto-Caananite script in around the 11th century BC, which in turn borrowed ideas from Egyptian hieroglyphics. This writing system was an abjad — that is, a writing system in which only consonants are represented. This script was adapted by the Greeks, who adapted certain consonantal signs to represent their vowels. The Cumae alphabet, a variant of the early Greek alphabet gave rise to the Etruscan alphabet, and its own descendants, such as the Latin alphabet and Runes. Other descendants from the Greek alphabet include the Cyrillic alphabet, used to write Russian, among others. The Phoenician system was also adapted into the Aramaic script, from which the Hebrew script and also that of Arabic are descended.
The Tifinagh script (Berber languages) is descended from the Libyco-Berber script which is assumed to be of Phoenician origin.
## Mesoamerica
A stone slab with 3,000-year-old writing was discovered in the Mexican state of Veracruz, and is an example of the oldest script in the Western Hemisphere preceding the oldest Zapotec writing dated to about 500 BC. [6] [7] [8]
Of several pre-Colombian scripts in Mesoamerica, the one that appears to have been best developed, and the only one to be deciphered, is the Maya script. The earliest inscriptions which are identifiably Maya date to the 3rd century BC, and writing was in continuous use until shortly after the arrival of the Spanish conquistadores in the 16th century AD. Maya writing used logograms complemented by a set of syllabic glyphs, somewhat similar in function to modern Japanese writing.
# Creation of text or information
## Creativity
## Author
## Writer
## Critiques
Template:Unreferencedsection
Writers sometimes search out others to evaluate or criticize their work. To this end, many writers join writing circles, often found at local libraries or bookstores. With the evolution of the Internet, writing circles have started to go online.
Template:Wikibookspar | https://www.wikidoc.org/index.php/Writing | |
44382b8a9b9ad629f31cceaa07efdb208435bc11 | wikidoc | XPNPEP1 | XPNPEP1
Xaa-Pro aminopeptidase 1 is an enzyme that in humans is encoded by the XPNPEP1 gene.
# Function
X-prolyl aminopeptidase (EC 3.4.11.9) is a proline-specific metalloaminopeptidase that specifically catalyzes the removal of any unsubstituted N-terminal amino acid that is adjacent to a penultimate proline residue. Because of its specificity toward proline, it has been suggested that X-prolyl aminopeptidase is important in the maturation and degradation of peptide hormones, neuropeptides, and tachykinins, as well as in the digestion of otherwise resistant dietary protein fragments, thereby complementing the pancreatic peptidases. Deficiency of X-prolyl aminopeptidase results in excretion of large amounts of imino-oligopeptides in urine (Blau et al., 1988).
# Model organisms
Model organisms have been used in the study of XPNPEP1 function. A conditional knockout mouse line called Xpnpep1tm1a(KOMP)Wtsi was generated at the Wellcome Trust Sanger Institute. Male and female animals underwent a standardized phenotypic screen to determine the effects of deletion. Additional screens performed: - In-depth immunological phenotyping - in-depth bone and cartilage phenotyping | XPNPEP1
Xaa-Pro aminopeptidase 1 is an enzyme that in humans is encoded by the XPNPEP1 gene.[1]
# Function
X-prolyl aminopeptidase (EC 3.4.11.9) is a proline-specific metalloaminopeptidase that specifically catalyzes the removal of any unsubstituted N-terminal amino acid that is adjacent to a penultimate proline residue. Because of its specificity toward proline, it has been suggested that X-prolyl aminopeptidase is important in the maturation and degradation of peptide hormones, neuropeptides, and tachykinins, as well as in the digestion of otherwise resistant dietary protein fragments, thereby complementing the pancreatic peptidases. Deficiency of X-prolyl aminopeptidase results in excretion of large amounts of imino-oligopeptides in urine (Blau et al., 1988).[supplied by OMIM][1]
# Model organisms
Model organisms have been used in the study of XPNPEP1 function. A conditional knockout mouse line called Xpnpep1tm1a(KOMP)Wtsi was generated at the Wellcome Trust Sanger Institute.[2] Male and female animals underwent a standardized phenotypic screen[3] to determine the effects of deletion.[4][5][6][7] Additional screens performed: - In-depth immunological phenotyping[8] - in-depth bone and cartilage phenotyping[9] | https://www.wikidoc.org/index.php/XPNPEP1 | |
0f57a3a7019b470ab00d574e96bc2d663a1749f9 | wikidoc | Y-23684 | Y-23684
Y-23684 is an anxiolytic drug with a novel chemical structure, which is used in scientific research. It has similar effects to benzodiazepine drugs, but is structurally distinct and so is classed as a nonbenzodiazepine anxiolytic.
Y-23684 is a nonselective partial agonist at GABAA receptors. It has primarily anxiolytic and anticonvulsant effects, with sedative and muscle relaxant effects only appearing at higher doses. It produces little ataxia or potentiation of other sedatives such as ethanol or barbiturates when compared to the benzodiazepines diazepam and clobazam in animal tests.
Y-23684 has a favourable pharmacological profile, producing strong anxiolytic and moderate anticonvulsant effects at low doses that cause little or no sedative side effects. It has been proposed for development for human medical use, but has not yet gone beyond animal tests. | Y-23684
Y-23684 is an anxiolytic drug with a novel chemical structure, which is used in scientific research.[1][2] It has similar effects to benzodiazepine drugs, but is structurally distinct and so is classed as a nonbenzodiazepine anxiolytic.
Y-23684 is a nonselective partial agonist at GABAA receptors. It has primarily anxiolytic and anticonvulsant effects, with sedative and muscle relaxant effects only appearing at higher doses. It produces little ataxia or potentiation of other sedatives such as ethanol or barbiturates when compared to the benzodiazepines diazepam and clobazam in animal tests.[3][4][5]
Y-23684 has a favourable pharmacological profile, producing strong anxiolytic and moderate anticonvulsant effects at low doses that cause little or no sedative side effects. It has been proposed for development for human medical use, but has not yet gone beyond animal tests.[6]
Template:Pharmacology-stub | https://www.wikidoc.org/index.php/Y-23684 | |
c58277941ae0a73fcebad443b90956cc52fafa39 | wikidoc | ZC3H12B | ZC3H12B
ZC3H12B, also known as CXorf32 or MCPIP2, is a protein encoded by gene ZC3H12B located on chromosome Xq12 in humans.
# Gene
The ZC3H12B gene is composed of 19,709 base pairs (bp) and contains 5 exons. It is located on the X chromosome at q12 on the plus strand.
- ZC3H12B Locus.
ZC3H12B Locus.
ZC3H12B contains a ribonuclease domain, as well as a CCCH-type zinc finger domain. Ribonucleases (RNases) degrade RNA and are involved in the RNA maturation process. They are also a line of defense against viral RNA (D'Alessio and Riordan 1997). CCCH-type zinc fingers are associated with mRNA destabilization. CCCH-type zinc fingers have been shown to turn over mRNA without the removal of the PolyA tail (Lai and Blackshear 2001). ZC3H12B and its paralogs ZC3H12A, ZC3H12C and ZC3H12D all contain CCCH-type zinc finger domains, which have been associated with cell cycle and growth phase transitions in eukaryotes (InterPro).
## Promoter
Genomatix ElDorado program predicted a 601 bp promoter upstream of the ZC3H12B gene with multiple transcription factor binding sites including nuclear factor of activated T-cells and ribonucleoprotein associated zinc finger protein MOK-2 (also known as ZNF239).
- Transcription factor binding site predictions in the promoter of ZC3H12B.
Transcription factor binding site predictions in the promoter of ZC3H12B.
# mRNA
ZC3H12B contains 7273 bp mRNA. There is only one predicted transcript by Aceview.
No folding patterns have been predicted (Mfold). There are for introns excised from ZC3H12B.
- Aceview single-predicted mRNA variant in ZC3H12B.
Aceview single-predicted mRNA variant in ZC3H12B.
# Protein
ZC3H12B is a probable ribonuclease containing CCCH-type zinc finger domain and ribonuclease domains.
The 836 amino acid protein has a predicted molecular weight of 94.2 kdal. It does not contain a signal peptide or a transmembrane region. PSORTII predicted 65.2% probability of nuclear location. CCCH-type zinc fingers and ribonucleases are presumably located in the nucleus for RNA cleaving and specifically, RNA hairpin cleaving (Boysen and Hearn 2008).
## Structural characteristics
The protein secondary structure is a mixture of alpha helices and beta strands.
The two domains identified so far are the ribonuclease and CCCH-type zinc finger domains.
Shown below is a conserved domain of ZC3H12B paralog, Mcpip1 (or ZC3H12A). In a BLAST structure comparison, there was an 82% identity match with 24% query coverage, with a predicted e-value of 2e-118.
82% identity match is enough to make comparisons of ZC3H12B and Mcpip1 (ZC3H12A) zinc finger conserved domain, which are both predicted to be composed of beta strands and alpha helices.
- Cn3D rendering of Mcpip1 conserved domain with zinc-finger motif.
Cn3D rendering of Mcpip1 conserved domain with zinc-finger motif.
## Post-translational modification
Phobius program predicted non-cytoplasmic protein location. NetPhos 2.0. predicted 63 phosphorylation sites in ZC3H12B, which are marked on the conceptual translation. YinOYang1.2. predicted three 0-Beta-GlcNAc attachment sites, which are competing with phosphorylation sites. 0-Beta-GlcNAc is presumably the only type of glycosylation occurring in the nucleus and/or cytoplasm of cells. There is a notable link between antigen activation by lymphocytes and dynamic 0-B-Glycosylation in nuclear proteins (Hart and Akimoto). NetNGlyc predicted glycosylation sites; however, these sites were excluded because the protein is likely nuclear and would not undergo this form of glycosylation. There were no predicted acetylation sites at the N-terminus of the protein. This is unusual because approximately 85% of human proteins are acetylated at the N terminus for synthesis, stabilization and localization of proteins (Van Damm et al.). No positive, negative or mixed charge clusters present. No hydrophobic segments detected (SAPS SDSC Biology Workbench). MitoProtII did not detect any mitochondria export signals. These post-translational tests suggest the protein is located in the nucleus and undergoes dynamic phosphorylation and 0-Beta-GlcNAc modifications.
# Evolution
Select domains of ZC3H12B are conserved in most vertebrates, arthropods and annelids. There are not conserved domains in domains bacteria or archaea. There were not significantly conserved domains in yeasts, plants or protists.
## Paralogs
There are three paralogs of ZC3H12B which are in the same CCCH-type zinc finger family, all which maintain greater than 50% identity to ZC3H12B based on BLAST analysis (NCBI).
## Orthologs
ZC3H12B is conserved in mammals, birds, insects and nematodes (BLAST). See the table below for the summary of orthologs of ZC3H12B in humans.
# Expression and function
Microarrays in normal tissue expression profiling showed increased expression of the gene in the pancreas, prostate, brain, spinal cord and thymus (GEO). Unlike its paralogs, it is not expressed in macrophage-activated tissues, which indicates the paralogous relationship to the inflammatory response (Liang et al. 2008). ZC3H12B is expressed transiently in brain, thymus and testis tissues (EST).
# Interaction
Predicted interactions by Ingenuity Systems showed no drug targeting molecules in pathway and no known drug targets. The listed top functions and diseases were cancer, organismal injury and abnormalities, reproductive system disease. Several miRNA interactions were predicted. The predicted miRNA targets have yet to be matched to the ZC3H12B sequence and it is unclear whether there is an interaction between the two. Tests such as Forster Resonance Energy Transfer (FRET), co-immunooprecipitation, two-hybrid screening, hydropathic complementarity, cluster-microarray and ChiP could be used in the future to test for new protein/chromatin interactions with ZC3H12B.
# Clinical significance
Deletions of the Xq12 locus has resulted in several disorders such as androgen insensitivity, susceptibility to prostate cancer, spinal and bulbar muscular atrophy of Kennedy and
mental retardation; however, no link has been found between these diseases and ZC3H12B (NCBI). | ZC3H12B
ZC3H12B, also known as CXorf32 or MCPIP2, is a protein encoded by gene ZC3H12B located on chromosome Xq12 in humans.
# Gene
The ZC3H12B gene is composed of 19,709 base pairs (bp) and contains 5 exons. It is located on the X chromosome at q12 on the plus strand.
- ZC3H12B Locus.
ZC3H12B Locus.
ZC3H12B contains a ribonuclease domain, as well as a CCCH-type zinc finger domain. Ribonucleases (RNases) degrade RNA and are involved in the RNA maturation process. They are also a line of defense against viral RNA (D'Alessio and Riordan 1997). CCCH-type zinc fingers are associated with mRNA destabilization. CCCH-type zinc fingers have been shown to turn over mRNA without the removal of the PolyA tail (Lai and Blackshear 2001). ZC3H12B and its paralogs ZC3H12A, ZC3H12C and ZC3H12D all contain CCCH-type zinc finger domains, which have been associated with cell cycle and growth phase transitions in eukaryotes (InterPro).
## Promoter
Genomatix ElDorado program predicted a 601 bp promoter upstream of the ZC3H12B gene with multiple transcription factor binding sites including nuclear factor of activated T-cells and ribonucleoprotein associated zinc finger protein MOK-2 (also known as ZNF239).
- Transcription factor binding site predictions in the promoter of ZC3H12B.
Transcription factor binding site predictions in the promoter of ZC3H12B.
# mRNA
ZC3H12B contains 7273 bp mRNA. There is only one predicted transcript by Aceview.
No folding patterns have been predicted (Mfold). There are for introns excised from ZC3H12B.
- Aceview single-predicted mRNA variant in ZC3H12B.
Aceview single-predicted mRNA variant in ZC3H12B.
# Protein
ZC3H12B is a probable ribonuclease containing CCCH-type zinc finger domain and ribonuclease domains.
The 836 amino acid protein has a predicted molecular weight of 94.2 kdal. It does not contain a signal peptide or a transmembrane region. PSORTII predicted 65.2% probability of nuclear location. CCCH-type zinc fingers and ribonucleases are presumably located in the nucleus for RNA cleaving and specifically, RNA hairpin cleaving (Boysen and Hearn 2008).
## Structural characteristics
The protein secondary structure is a mixture of alpha helices and beta strands.
The two domains identified so far are the ribonuclease and CCCH-type zinc finger domains.
Shown below is a conserved domain of ZC3H12B paralog, Mcpip1 (or ZC3H12A). In a BLAST structure comparison, there was an 82% identity match with 24% query coverage, with a predicted e-value of 2e-118.
82% identity match is enough to make comparisons of ZC3H12B and Mcpip1 (ZC3H12A) zinc finger conserved domain, which are both predicted to be composed of beta strands and alpha helices.
- Cn3D rendering of Mcpip1 conserved domain with zinc-finger motif.
Cn3D rendering of Mcpip1 conserved domain with zinc-finger motif.
## Post-translational modification
Phobius program predicted non-cytoplasmic protein location. NetPhos 2.0. predicted 63 phosphorylation sites in ZC3H12B, which are marked on the conceptual translation. YinOYang1.2. predicted three 0-Beta-GlcNAc attachment sites, which are competing with phosphorylation sites. 0-Beta-GlcNAc is presumably the only type of glycosylation occurring in the nucleus and/or cytoplasm of cells. There is a notable link between antigen activation by lymphocytes and dynamic 0-B-Glycosylation in nuclear proteins (Hart and Akimoto). NetNGlyc predicted glycosylation sites; however, these sites were excluded because the protein is likely nuclear and would not undergo this form of glycosylation. There were no predicted acetylation sites at the N-terminus of the protein. This is unusual because approximately 85% of human proteins are acetylated at the N terminus for synthesis, stabilization and localization of proteins (Van Damm et al.). No positive, negative or mixed charge clusters present. No hydrophobic segments detected (SAPS SDSC Biology Workbench). MitoProtII did not detect any mitochondria export signals. These post-translational tests suggest the protein is located in the nucleus and undergoes dynamic phosphorylation and 0-Beta-GlcNAc modifications.
# Evolution
Select domains of ZC3H12B are conserved in most vertebrates, arthropods and annelids. There are not conserved domains in domains bacteria or archaea. There were not significantly conserved domains in yeasts, plants or protists.
## Paralogs
There are three paralogs of ZC3H12B which are in the same CCCH-type zinc finger family, all which maintain greater than 50% identity to ZC3H12B based on BLAST analysis (NCBI).
## Orthologs
ZC3H12B is conserved in mammals, birds, insects and nematodes (BLAST). See the table below for the summary of orthologs of ZC3H12B in humans.
# Expression and function
Microarrays in normal tissue expression profiling showed increased expression of the gene in the pancreas, prostate, brain, spinal cord and thymus (GEO). Unlike its paralogs, it is not expressed in macrophage-activated tissues, which indicates the paralogous relationship to the inflammatory response (Liang et al. 2008). ZC3H12B is expressed transiently in brain, thymus and testis tissues (EST).
# Interaction
Predicted interactions by Ingenuity Systems showed no drug targeting molecules in pathway and no known drug targets. The listed top functions and diseases were cancer, organismal injury and abnormalities, reproductive system disease. Several miRNA interactions were predicted. The predicted miRNA targets have yet to be matched to the ZC3H12B sequence and it is unclear whether there is an interaction between the two. Tests such as Forster Resonance Energy Transfer (FRET), co-immunooprecipitation, two-hybrid screening, hydropathic complementarity, cluster-microarray and ChiP could be used in the future to test for new protein/chromatin interactions with ZC3H12B.
# Clinical significance
Deletions of the Xq12 locus has resulted in several disorders such as androgen insensitivity, susceptibility to prostate cancer, spinal and bulbar muscular atrophy of Kennedy and
mental retardation; however, no link has been found between these diseases and ZC3H12B (NCBI). | https://www.wikidoc.org/index.php/ZC3H12B | |
e61e6fe6cfee64344395517d34a07d2836dd4d4d | wikidoc | ZCCHC18 | ZCCHC18
Zinc finger CCHC-type containing 18 (ZCCHC18) is a protein that in humans is encoded by ZCCHC18 gene. It is also known as Smad-interacting zinc finger protein 2 (SIZN2), para-neoplastic Ma antigen family member 7b (PNMA7B), and LOC644353. Other names such as zinc finger, CCHC domain containing 12 pseudogene 1, P0CG32, ZCC18_HUMAN had been used to describe this protein.
ZCCHC18 belongs to the ZCCHC12 family or para-neoplastic Ma (PNMA). It is a ligand-dependent nuclear receptor transcription coactivator. Its zinc finger domain is CCHC which binds to zinc ion (see protein section for detail information on CCHC motif).
It is worthwhile to mention that in mammals, PNMA is derived from Ty3/Gypsy long terminal repeat (LTR) retrotransposons and PNMA family encodes the Gag-like protein. Although the full functions remain unknown, most PNMA genes are expressed in brains of macaques and mice. PNMA1, 2 and 3 were found in the serum of patients with paraneoplastic neurological disorders. The family also includes modulator of apoptosis 1, having a role in death receptor-dependent apoptosis.
# Gene
## Location
ZCCHC18 gene locates at the long arm of X chromosome, loci position Xq22.2. This gene contains 3 exons and 2 distinct gt-ag introns, being transcribed into 3 alternatively spliced mRNAs. However, only one spliced mRNA (NM_001143978.2, 2951 bp) putatively encodes a 403 amino acid protein, whereas the others does not encode proteins.
## Gene Neighborhood
Nearby genes include SLC25A53 (on the negative strand) (about 8,000 bit/s upstream) and FAM199X (on the positive strand) (about 50,800 bit/s downstream).
## Expression
ZCCHC18 ubiquitously expresses in ovary, brain (cerebellum), endometrium, lymph node, spleen and 22 other tissues in human and other species. Based on RNA-Seq expression data from GTEx (53 tissues from 570 donors), highest median expression is in brain—cerebellum (4.74 RPKM) whereas the total median expression of 67.54 RPKM.
## Promoter
Possible transcription binding sites is analyzed by Genomatix, listed in the table below:
## Homology
### Orthologs
Orthologs of ZCCHC18 can be found in most Chordata (Mammalia, Amphibian, Reptilian, Osteichthyes, but not in Arthropod, Aves, Chondrichthyes), Echinoderm, and Cnidarian but not in Fungus, Plant, Ciliates, Archaea, nor Bacteria.
### Paralogs
Eight possible paralogs of ZCCHC18 were identified in Homo sapiens.
Note: PNMA4 (aliases: modulator of apoptosis 1, MOAP1) does not appear to be similar to ZCCHC18 (the identity and similarity between ZCCHC18 and MOAP1 are 15% and 32.1%, respectively).
# Transcript
## Splice Variants
Including 5’-UTR and 3’-UTR, ZCCHC18 spans from chrX:104,112,526-104,115,846 with a total of 3,321 base pairs (bps) (5’-UTR: 1206 bit/s and 3’-UTR: 523 bit/s). It contains 3 exons and 2 distinct gt-ag introns, being transcribed into 3 alternatively spliced mRNAs. However, only one spliced mRNA (NM_001143978.2, 2951 bit/s) putatively encodes a protein with 403 amino acids (coding region: hg38 chrX:104,114,112-104,115,323, total 1,212 bit/s), whereas others do not encode proteins.
Comparing to human ZCCHC18 mRNA which there are 3 isoforms, there are 7 isoforms of Zcchc18 in mouse (Mus musculus), and no isoform in cat (Felis catus) and leopard (Panthera pardus).
# Protein
ZCCHC18 is a human protein with 403 amino acids in length and has a predicted molecular weight of 45,160 daltons. Its basal isoelectric point is 7.02 (unphosphorylated state), and isoelectric point decreased with increased number of residues being phosphorylated. The common sequences of ZCCHC18 include KRED and LVIFM. It is generally electroneutral (there are no positive or negative charge clusters or segments) with no high hydrophobic segments.
## Secondary Structure
Secondary structure prediction of a not well-characterized protein can be performed by using PRBI database, Phyre2, and I-TASSER. The secondary structure prediction of ZCCHC18 was analyzed by Phyre2.
## Tertiary Structure
The tertiary structure was predicted by I-TASSER in the attempt to optimize C-score, TM-score, and cluster density. The predicted ZCCHC18 tertiary structure is shown in the figure..
## Post-Translational Modifications
The predicted post-translational modifications (PTMs) is obtained by using Prosite, and many other tools. The key post translation modifications are summarized here.
## Subcellular Localization
ZCCHC18 primary locates in the nucleus (appearance to be nuclear speck, a discrete extra-nucleolar subnuclear domain, under immunofluorescence microscopy).
## Function
Although the exact function of ZCCHC18 is still not fully known, the basic amino acid sequence of the zinc finger (Znf) CCHC-type protein can be well characterized as conservatively spaced cysteine and histidine. The Cys and His residues is completely conserved at position 1 (Cys), 4 (Cys), 9 (His), and 14 (Cys) . Conservatively substituted glycines occur at position 5 and 8, and aromatic or hydrophobic amino acids are at positions 2 (or 3) and 10. This motif is often expressed as Cys-X2-Cys-X4-His-X4-Cys.
The structure of zinc finger domains enables the protein to make tandem contact with target molecules through multiple finger-like protrusions. These domains can bind to zinc or other metals such as iron, or even no metal (stabilizing through salt bridges). The exact mechanism for how the Znf domain of ZCCHC18 work is still unknown.
## Interacting Proteins
ZCCHC18 can possibly interact with the intracellular domain of EGFR. This report was based on the two protein-protein interaction (PPI) approaches, the membrane yeast two-hybrid (MYTH) and the mammalian membrane two-hybrid (MMTH), to map the PPIs between human receptor tyrosine kinases (RTKs) and phosphatases.
# Clinical Significance
## Disease Association
By examining RNA-seq data from The Cancer Genome Atlas (TCGA), glioma has enhanced RNA expression (median 1.9 FPKM ) whereas other cancer types only have minimal expression (median expression level lower than 0.5 FPKM). In terms of the ZCCHC18 protein expression, squamous and basal cell carcinomas, and cases of urothelial cancers exhibited moderate to strong cytoplasmic immunoreactivity. Remaining cancer cells were weakly stained or negative. While interrogating 4440 tumor samples from 15 cancer types from TCGA, the analysis showed a vary protein mutation frequency in different cancer types. ZCCHC18 mutation happened frequently in endometrial cancer (~ 2.4%), followed by bladder cancer (~0.8%), head/neck carcinoma (~0.4%), ovarian cancer (~0.4%), and breast cancer (<0.2%).
## Genetic Testing
Currently, Fulgent Genetics is the only commercial company provides the genetic testing for deletion or duplication of ZCCHC18 through sequence analysis of the entire coding region (Next-Generation Sequencing) for possible diseases caused by mutations on this particular gene that are inherited from a parent's genome. However, the clinical validity and utility have not been proven yet. | ZCCHC18
Zinc finger CCHC-type containing 18 (ZCCHC18) is a protein that in humans is encoded by ZCCHC18 gene. It is also known as Smad-interacting zinc finger protein 2 (SIZN2), para-neoplastic Ma antigen family member 7b (PNMA7B), and LOC644353.[1][2] Other names such as zinc finger, CCHC domain containing 12 pseudogene 1, P0CG32, ZCC18_HUMAN had been used to describe this protein.
ZCCHC18 belongs to the ZCCHC12 family or para-neoplastic Ma (PNMA). It is a ligand-dependent nuclear receptor transcription coactivator. Its zinc finger domain is CCHC which binds to zinc ion (see protein section for detail information on CCHC motif).[3]
It is worthwhile to mention that in mammals, PNMA is derived from Ty3/Gypsy long terminal repeat (LTR) retrotransposons and PNMA family encodes the Gag-like protein.[4] Although the full functions remain unknown, most PNMA genes are expressed in brains of macaques and mice.[5] PNMA1, 2 and 3 were found in the serum of patients with paraneoplastic neurological disorders. The family also includes modulator of apoptosis 1, having a role in death receptor-dependent apoptosis.[6]
# Gene
## Location
ZCCHC18 gene locates at the long arm of X chromosome, loci position Xq22.2. This gene contains 3 exons and 2 distinct gt-ag introns, being transcribed into 3 alternatively spliced mRNAs. However, only one spliced mRNA (NM_001143978.2, 2951 bp) putatively encodes a 403 amino acid protein, whereas the others does not encode proteins.[7]
## Gene Neighborhood
Nearby genes include SLC25A53 (on the negative strand) (about 8,000 bit/s upstream) and FAM199X (on the positive strand) (about 50,800 bit/s downstream).[3]
## Expression
ZCCHC18 ubiquitously expresses in ovary, brain (cerebellum), endometrium, lymph node, spleen and 22 other tissues in human and other species.[8] Based on RNA-Seq expression data from GTEx (53 tissues from 570 donors), highest median expression is in brain—cerebellum (4.74 RPKM) whereas the total median expression of 67.54 RPKM.[9]
## Promoter
Possible transcription binding sites is analyzed by Genomatix,[10] listed in the table below:
## Homology
### Orthologs
Orthologs of ZCCHC18 can be found in most Chordata (Mammalia, Amphibian, Reptilian, Osteichthyes, but not in Arthropod, Aves, Chondrichthyes), Echinoderm, and Cnidarian but not in Fungus, Plant, Ciliates, Archaea, nor Bacteria.
### Paralogs
Eight possible paralogs of ZCCHC18 were identified in Homo sapiens.
Note: PNMA4 (aliases: modulator of apoptosis 1, MOAP1) does not appear to be similar to ZCCHC18 (the identity and similarity between ZCCHC18 and MOAP1 are 15% and 32.1%, respectively).
# Transcript
## Splice Variants
Including 5’-UTR and 3’-UTR, ZCCHC18 spans from chrX:104,112,526-104,115,846 with a total of 3,321 base pairs (bps) (5’-UTR: 1206 bit/s and 3’-UTR: 523 bit/s). It contains 3 exons and 2 distinct gt-ag introns, being transcribed into 3 alternatively spliced mRNAs. However, only one spliced mRNA (NM_001143978.2, 2951 bit/s) putatively encodes a protein with 403 amino acids (coding region: hg38 chrX:104,114,112-104,115,323, total 1,212 bit/s), whereas others do not encode proteins.[3][12][13]
Comparing to human ZCCHC18 mRNA which there are 3 isoforms, there are 7 isoforms of Zcchc18 in mouse (Mus musculus), and no isoform in cat (Felis catus) and leopard (Panthera pardus).
# Protein
ZCCHC18 is a human protein with 403 amino acids in length and has a predicted molecular weight of 45,160 daltons. Its basal isoelectric point is 7.02 (unphosphorylated state), and isoelectric point decreased with increased number of residues being phosphorylated. The common sequences of ZCCHC18 include KRED and LVIFM. It is generally electroneutral (there are no positive or negative charge clusters or segments) with no high hydrophobic segments.
## Secondary Structure
Secondary structure prediction of a not well-characterized protein can be performed by using PRBI database,[14] Phyre2,[11] and I-TASSER.[15] The secondary structure prediction of ZCCHC18 was analyzed by Phyre2.
## Tertiary Structure
The tertiary structure was predicted by I-TASSER[15] in the attempt to optimize C-score, TM-score, and cluster density. The predicted ZCCHC18 tertiary structure is shown in the figure..
## Post-Translational Modifications
The predicted post-translational modifications (PTMs) is obtained by using Prosite,[16] and many other tools.[17][18][19][20][21][22][23] The key post translation modifications are summarized here.
## Subcellular Localization
ZCCHC18 primary locates in the nucleus (appearance to be nuclear speck, a discrete extra-nucleolar subnuclear domain, under immunofluorescence microscopy).[24]
## Function
Although the exact function of ZCCHC18 is still not fully known, the basic amino acid sequence of the zinc finger (Znf) CCHC-type protein can be well characterized as conservatively spaced cysteine and histidine.[4] The Cys and His residues is completely conserved at position 1 (Cys), 4 (Cys), 9 (His), and 14 (Cys) [as the first Cys of the sequence labeled as Cys (1)]. Conservatively substituted glycines occur at position 5 and 8, and aromatic or hydrophobic amino acids are at positions 2 (or 3) and 10. This motif is often expressed as Cys-X2-Cys-X4-His-X4-Cys.
The structure of zinc finger domains enables the protein to make tandem contact with target molecules through multiple finger-like protrusions. These domains can bind to zinc or other metals such as iron, or even no metal (stabilizing through salt bridges).[25] The exact mechanism for how the Znf domain of ZCCHC18 work is still unknown.
## Interacting Proteins
ZCCHC18 can possibly interact with the intracellular domain of EGFR. This report was based on the two protein-protein interaction (PPI) approaches, the membrane yeast two-hybrid (MYTH) and the mammalian membrane two-hybrid (MMTH), to map the PPIs between human receptor tyrosine kinases (RTKs) and phosphatases.[26]
# Clinical Significance
## Disease Association
By examining RNA-seq data from The Cancer Genome Atlas (TCGA),[27] glioma has enhanced RNA expression (median 1.9 FPKM [Fragments Per Kilobase of exon per Million reads]) whereas other cancer types only have minimal expression (median expression level lower than 0.5 FPKM). In terms of the ZCCHC18 protein expression, squamous and basal cell carcinomas, and cases of urothelial cancers exhibited moderate to strong cytoplasmic immunoreactivity. Remaining cancer cells were weakly stained or negative. While interrogating 4440 tumor samples from 15 cancer types from TCGA,[10] the analysis showed a vary protein mutation frequency in different cancer types. ZCCHC18 mutation happened frequently in endometrial cancer (~ 2.4%), followed by bladder cancer (~0.8%), head/neck carcinoma (~0.4%), ovarian cancer (~0.4%), and breast cancer (<0.2%).
## Genetic Testing
Currently, Fulgent Genetics is the only commercial company provides the genetic testing for deletion or duplication of ZCCHC18 through sequence analysis of the entire coding region (Next-Generation Sequencing) for possible diseases caused by mutations on this particular gene that are inherited from a parent's genome. However, the clinical validity and utility have not been proven yet.[28] | https://www.wikidoc.org/index.php/ZCCHC18 | |
5e05b80aa5f9793dd3ebd6c8ceae32f91bcd52ef | wikidoc | ZFYVE16 | ZFYVE16
Zinc finger FYVE domain-containing protein 16 is a protein that in humans is encoded by the ZFYVE16 gene.
The ZFYVE16 gene encodes endofin, an endosomal protein implicated in regulating membrane trafficking. It is characterized by the presence of a phosphatidylinositol 3-phosphate-binding FYVE domain positioned in the middle of the molecule (Seet et al., 2004).
In melanocytic cells ZFYVE16 gene expression may be regulated by MITF.
# Interactions
ZFYVE16 has been shown to interact with TOM1. | ZFYVE16
Zinc finger FYVE domain-containing protein 16 is a protein that in humans is encoded by the ZFYVE16 gene.[1][2]
The ZFYVE16 gene encodes endofin, an endosomal protein implicated in regulating membrane trafficking. It is characterized by the presence of a phosphatidylinositol 3-phosphate-binding FYVE domain positioned in the middle of the molecule (Seet et al., 2004).[supplied by OMIM][2]
In melanocytic cells ZFYVE16 gene expression may be regulated by MITF.[3]
# Interactions
ZFYVE16 has been shown to interact with TOM1.[4] | https://www.wikidoc.org/index.php/ZFYVE16 | |
1eb42f86588816df6599ef51f018257d9ce77eae | wikidoc | Zantrex | Zantrex
Zantrex-3 is a herbal supplement marketed by "Zoller Laboratories", a subsidiary of Basic Research of Salt Lake City, Utah. It is marketed towards people under 30 in fast paced television advertisements depicting athletic-looking people. A speaker loudly proclaims Zantrex as "America's number 1 selling weight loss pill!".
# Ingredients
Its active ingredients include Yerba Mate, Guarana and regular caffeine. It's estimated that the pill contains as much caffeine as 3-4 cups of coffee . Additional ingredients include green tea extract, Damiana (a South American aphrodisiac), Schizonepeta, Ginseng, Maca root, Niacin and Kola nut.
# Side effects
The pill may potentially have side effects similar to those associated with excessive caffeine consumption.
Listed side effects include:
- Jitters, anxiety, increased sweating
- Increase in heart rate, increase in blood pressure
- Nausea, stomachache, diarrhea
- Loss or suppressed appetite
- Cold sweats, restlessness, shaking, irritability
- Increase in urination (as caffeine is a mild diuretic)
- Caffeine can be addictive
- One may "crash" when going off of Zantrex-3
- Niacin is a vasodilator, and in some cases, use of Zantrex-3 causes uncontrollable swelling in all parts of the body. In severe cases, users develop the condition Angioedema
# Criticism
The marketing campaign of the pill has been criticized for its lack of evidence, in the form of scientific studies, listed supporting the claims. One reviewer said, "If you alter your diet accordingly, monitor your caloric intake, and implement a practical exercise program, Zantrex 3 may provide you with an extra edge."
# Pop Culture
Near the end of the fifth season of VH1's Celebrity Fit Club, contestant Dustin Diamond gained a pathetic five pounds. At the next weigh-in, just two weeks later, he had lost five pounds. He revealed to the Fit Club panel that he had been taking Zantrex-3 and was pleased that he had undone the damage from the previous weigh-in. At the final weigh-in, another two weeks later, Diamond had lost an additional thirteen pounds. He was criticized extensively by both the panel as well as his fellow contestants for his use of Zantrex-3 as a dietary supplement. | Zantrex
Zantrex-3 is a herbal supplement marketed by "Zoller Laboratories", a subsidiary of Basic Research of Salt Lake City, Utah. It is marketed towards people under 30 in fast paced television advertisements depicting athletic-looking people. A speaker loudly proclaims Zantrex as "America's number 1 selling weight loss pill!".
# Ingredients
Its active ingredients include Yerba Mate, Guarana and regular caffeine. It's estimated that the pill contains as much caffeine as 3-4 cups of coffee [1]. Additional ingredients include green tea extract, Damiana (a South American aphrodisiac), Schizonepeta, Ginseng, Maca root, Niacin and Kola nut.
# Side effects
The pill may potentially have side effects similar to those associated with excessive caffeine consumption.
Listed side effects include:
- Jitters, anxiety, increased sweating
- Increase in heart rate, increase in blood pressure
- Nausea, stomachache, diarrhea
- Loss or suppressed appetite
- Cold sweats, restlessness, shaking, irritability
- Increase in urination (as caffeine is a mild diuretic)
- Caffeine can be addictive
- One may "crash" when going off of Zantrex-3 [2]
- Niacin is a vasodilator, and in some cases, use of Zantrex-3 causes uncontrollable swelling in all parts of the body. In severe cases, users develop the condition Angioedema
# Criticism
The marketing campaign of the pill has been criticized for its lack of evidence, in the form of scientific studies, listed supporting the claims. One reviewer said, "If you alter your diet accordingly, monitor your caloric intake, and implement a practical exercise program, Zantrex 3 may provide you with an extra edge."
# Pop Culture
Near the end of the fifth season of VH1's Celebrity Fit Club, contestant Dustin Diamond gained a pathetic five pounds. At the next weigh-in, just two weeks later, he had lost five pounds. He revealed to the Fit Club panel that he had been taking Zantrex-3 and was pleased that he had undone the damage from the previous weigh-in. At the final weigh-in, another two weeks later, Diamond had lost an additional thirteen pounds. He was criticized extensively by both the panel as well as his fellow contestants for his use of Zantrex-3 as a dietary supplement.
# External links
- The Zantrex-3 Official Website
Template:WikiDoc Sources | https://www.wikidoc.org/index.php/Zantrex | |
295abd4d685cc5130a00059bd53e6d85d37da47e | wikidoc | Zedoary | Zedoary
Zedoary (Curcuma zedoaria, known as kacōramu in Telugu) is the name for a perennial herb and member of the genus Curcuma Linn., family Zingiberaceae. The plant is native to India and Indonesia. It was introduced to Europe by Arabs around the sixth century, but its use as a spice in the West today is extremely rare, having been replaced by ginger.
Zedoary is a rhizome that grows in tropical and subtropical wet forest regions. The fragrant plant bears yellow flowers with red and green bracts and the underground stem section is large and tuberous with numerous branches. The leaf shoots of the zedoary are long and can reach 1 metre (3 feet) in height.
The edible root of zedoary has a white interior and a fragrance reminiscent of mango, however its flavour is more similar to ginger, except with a very bitter aftertaste. In Indonesia it is ground to a powder and added to curry pastes, whereas in India it tends to be used fresh or pickled.
Zedoary is also used in some traditional eastern medicines where it is reputed to be an aid to digestion, a relief for colic and an agent for purifying the blood.
The essential oil produced from the dried roots of Curcuma zedoaria is used in perfumery and soap fabrication, as well as an ingredient in bitter tonics.
de:Zitwerwurzel
it:Curcuma zedoaria | Zedoary
Zedoary (Curcuma zedoaria, known as kacōramu in Telugu) is the name for a perennial herb and member of the genus Curcuma Linn., family Zingiberaceae. The plant is native to India and Indonesia. It was introduced to Europe by Arabs around the sixth century, but its use as a spice in the West today is extremely rare, having been replaced by ginger.
Zedoary is a rhizome that grows in tropical and subtropical wet forest regions. The fragrant plant bears yellow flowers with red and green bracts and the underground stem section is large and tuberous with numerous branches. The leaf shoots of the zedoary are long and can reach 1 metre (3 feet) in height.
The edible root of zedoary has a white interior and a fragrance reminiscent of mango, however its flavour is more similar to ginger, except with a very bitter aftertaste. In Indonesia it is ground to a powder and added to curry pastes, whereas in India it tends to be used fresh or pickled.
Zedoary is also used in some traditional eastern medicines where it is reputed to be an aid to digestion, a relief for colic and an agent for purifying the blood.
The essential oil produced from the dried roots of Curcuma zedoaria is used in perfumery and soap fabrication, as well as an ingredient in bitter tonics.
de:Zitwerwurzel
it:Curcuma zedoaria
Template:Herbs & spices
Template:WikiDoc Sources | https://www.wikidoc.org/index.php/Zedoary | |
10c6562d50fabb10b30e98fecc18ac24092a4b85 | wikidoc | Zoology | Zoology
Zoology is a biological science that pertains to animals. Animals choose to move whereas plants are moved. Animals feed on bio-organic material and digest it internally. Plants can convert inorganic and organic material into bio-organic material. Cell walls of an animal are flexible. Animal cells possess junctions which are impermeable to fluids (tight junctions), junctions which allow intercellular communication, or the transfer of low molecular-weight substances (gap junctions), and structures which adhere to other cells to form tissue via structural units (desmosomes).
# Genetics
Genetics is the study of the genes, how they affect organisms, and how they are passed from one generation to the next. A scientist that studies genetics is called a geneticist.
Def. a "branch of biology that deals with the transmission and variation of inherited characteristics, in particular chromosomes and DNA" is called genetics.
DNA, deoxyribonucleic acid, is a molecule found in almost every cell of every body of every organism. DNA contains genes, which are the basic instruction codes for making and running a living organism. Strands of DNA make up chromosomes. (Chromosomes are made of DNA, which is made up of genes.)
Genes, through DNA and chromosomes, are passed from one generation to the next by inheritance. Because of this, offspring resemble their parents. Through mixing and occasional mutation, genes can change. When genes change, how the organism forms and how it works may be changed.
How all these changes affect individuals, populations, and entire species is the work of geneticists.
"A recent comparison of the draft sequences of mouse and human genomes has shed light on the selective forces that have predominated in their recent evolutionary histories. In particular, mouse-specific clusters of homologues associated with roles in reproduction, immunity and host defence appear to be under diversifying positive selective pressure, as indicated by high ratios of non-synonymous to synonymous substitution rates. These clusters are also frequently punctuated by homologous pseudogenes. They thus have experienced numerous gene death, as well as gene birth, events. These regions appear, therefore, to have borne the brunt of adaptive evolution that underlies physiological and behavioural innovation in mice. We predict that the availability of numerous animal genomes will give rise to a new field of genome zoology in which differences in animal physiology and ethology are illuminated by the study of genomic sequence variations."
# Biology
Def. the "study of all life or living matter" is called biology.
On the right is a drawing of the archaean Haloquadratum walsbyi.
As the study of biology is the study of all living organisms, zoology is a specialty of biology. All zoologists are also considered biologists.
Other branches of biology include botany (the study of plants), mycology (the study of fungi), phycology (the study of algae), and virology (the study of viruses).
# Animals
The biological definition of animals includes all members of the kingdom Animalia.
Def. "a multicellular organism that is usually mobile, whose cells are not encased in a rigid cell wall (distinguishing it from plants and fungi) and which derives energy solely from the consumption of other organisms" is called an animal.
In colloquial use, as a consequence of anthropocentrism, the term animal is sometimes used nonscientifically to refer only to non-human animals.
Animals are eukaryotic and multicellular, unlike bacteria, which are prokaryotic, and unlike protists, which are eukaryotic but unicellular. Unlike plants and algae, which are autotrophs, producing their own nutrients animals are heterotrophic, feeding on organic material and digesting it internally. With very few exceptions, animals breathe oxygen and respire aerobically. All animals are motile (able to spontaneously move their bodies) during at least part of their life cycle, but some animals, such as sponges, corals, mussels, and barnacles, later become sessile. The blastula is a stage in embryogenesis, embryonic development, that is unique to most animals, allowing cells to be differentiated into specialised tissues and organs.
All animals are composed of cells, surrounded by a characteristic extracellular matrix composed of collagen and elastic glycoproteins. During development, the animal extracellular matrix forms a relatively flexible framework upon which cells can move about and be reorganised, making the formation of complex structures possible. This may be calcified, forming structures such as an exoskeleton of shells, bones, and spicules. In contrast, the cells of other multicellular organisms (primarily algae, plants, and fungi) are held in place by cell walls, and so develop by progressive growth. Animal cells uniquely possess the cell junctions called tight junctions, gap junctions, and desmosomes.
With few exceptions—in particular, the sponges and placozoans—animal bodies are differentiated into tissues. These include muscles, which enable locomotion, and nerve tissues, which transmit signals and coordinate the body. Typically, there is also an internal digestive chamber with either one opening (as in flatworms) or two openings (as in deuterostomes).
Nearly all animals make use of some form of sexual reproduction. They produce haploid gametes by meiosis; the smaller, motile gametes are spermatozoa and the larger, non-motile gametes are ova. These fuse to form zygotes, which develop via mitosis into a hollow sphere, called a blastula. In sponges, blastula larvae swim to a new location, attach to the seabed, and develop into a new sponge. In most other groups, the blastula undergoes more complicated rearrangement. It first invaginates to form a gastrula with a digestive chamber and two separate germ layers, an external ectoderm and an internal endoderm. In most cases, a third germ layer, the mesoderm, also develops between them. These germ layers then differentiate to form tissues and organs.
Repeated instances of inbreeding, mating with a close relative, during sexual reproduction generally leads to inbreeding depression within a population due to the increased prevalence of harmful recessive traits. Animals have evolved numerous mechanisms for inbreeding avoidance, or avoiding close inbreeding. In some species, such as the splendid fairywren (Malurus splendens), females benefit by mating with multiple males, thus producing more offspring of higher genetic quality.
Some animals are capable of asexual reproduction, which often results in a genetic clone of the parent. This may take place through fragmentation; budding, such as in Hydra and other cnidarians; or parthenogenesis, where fertile eggs are produced without mating, such as in aphids.
Animals are categorised into ecological groups depending on how they obtain or consume organic material, including carnivores, herbivores, omnivores, detritivores, and parasites. Interactions between animals form complex food webs. In carnivorous or omnivorous species, predation is a consumer-resource interaction where a predator feeds on another organism (called its prey). Selective pressures imposed on one another lead to an evolutionary arms race between predator and prey, resulting in various anti-predator adaptations. Almost all multicellular predators are animals. Some consumers use multiple methods; for example, in parasitoid wasps, the larvae feed on the hosts' living tissues, killing them in the process, but the adults primarily consume nectar from flowers. Other animals may have very specific feeding behaviours, such as hawksbill sea turtles that primarily eat sponges.
Most animals rely on the energy produced by plants through photosynthesis. Herbivores eat plant material directly, while carnivores, and other animals on higher trophic levels, typically acquire energy (in the form of reduced carbon) by eating other animals. The carbohydrates, lipids, proteins, and other biomolecules are broken down to allow the animal to grow and to sustain biological processes such as locomotion. Animals living close to hydrothermal vents and cold seeps on the dark sea floor do not depend on the energy of sunlight. Rather, archaea and bacteria in these locations produce organic matter through chemosynthesis (by oxidizing inorganic compounds, such as methane) and form the base of the local food web.
Animals originally evolved in the sea. Lineages of arthropods colonised land around the same time as land plants, probably between 510–471 million years ago during the Late Cambrian or Early Ordovician. Vertebrates such as the Sarcopterygii, lobe-finned fish, Tiktaalik started to move on to land in the late Devonian, about 375 million years ago. Animals occupy virtually all of earth's habitats and microhabitats, including salt water, hydrothermal vents, fresh water, hot springs, swamps, forests, pastures, deserts, air, and the interiors of animals, plants, fungi and rocks. Animals are however not particularly heat tolerant; very few of them can survive at constant temperatures above 50 °C. Only very few species of animals (mostly nematodes) inhabit the most extreme cold deserts of continental Antarctica.
# Theoretical zoology
Def. "that part of biology which relates to the animal kingdom, including the structure, embryology, evolution, classification, habits, and distribution of all animals, both living and extinct" is called zoology.
"Compare both photos, in the photo above and the "civil war soldiers". All this is model of a pterodactyl. Not sure of the age, but I'm sure it was like a practical joke back in the day. The "bigfoot" of it's day so to speak. Compare the photos and you'll see that it's the exact same model. The above photo would be a better looking fake than the civil war photo. Any real dead animal is limp until rigor sets in, and even then, it has to something right? Why is the guy in the center of the above photo not holding up the main weight of the body? He's practically leaning on it. It's because it's a stiff model that supports itself. And I'm willing to bet that if you were to look at some older photos around the turn of the 19th century of some paleontology exhibits, you'd find this exact same model at some point. The Bone Wars started in the 1880s and made dinosaurs all the rage."
# Zoography
Zoography is descriptive zoology. Animals are described in comparison with other organisms, and their surroundings. This comparison takes into account variation among individuals and populations, and organizes it into systems and classifications that are used for making predictions, such as the evolutionary relationships among organisms.
The branches of zoology focusing on a particular taxonomic group (mammals, etc.) are often considered part of zoography.
Def. a "description of animals, their forms, and habits; descriptive zoology" is called zoography.
# Vertebrate Zoology
Vertebrate zoology is the study of vertebrates, the animals that have a spinal column. This covers only about 3% of all known species.
# Mammalogy
Def. the "study of mammals" is called mammalogy.
Scientists who study mammalogy are called mammalogists.
Mammals are endothermic vertebrates that have fur or hair and feed milk to their young. Milk is a fluid produced by mammary glands.
There are about 5000 species of living mammal known to science. Mammals live in every habitat on Earth. They range in size from the Etruscan shrew (Suncus etruscus), the smallest living mammal, to the blue whale (Balaenoptera musculus) which is the largest animal to have ever lived. Humans (Homo sapiens) are also mammals. They are placed in the taxonomic class Mammalia.
Def. a "taxonomic subclass within the class Reptilia – (or a class or clade within superclass Tetrapoda) - the extinct “mammal-like” reptiles " is called the Synapsida.
Def. a "taxonomic clade within the clade Reptiliomorpha – the most recent common ancestor of extant mammals and reptiles, and all its descendants; the reptiles, birds and mammals, collectively, all of which have an amnion during development" is called the Amniota.
External Resources:
- a journal that consists of species accounts of mammals from around the world.
# Archosaurology
Def. the study of the Archosauria is called archosaurology.
The Archosauria include the Pseudosuchia and the Ornithodira.
The Pseudosuchia include the Crocodylomorpha: Crocodylia, †Aetosauria, †Phytosauria, †Rauisuchia and the unplaced families: †Atoposauridae, †Bernissartiidae, and †Peirosauridae.
The Ornithodira include the Dinosauromorpha and †Pterosauromorpha.
The Dinosauromorpha include the Dinosauria.
# Ornithology
Def. "the scientific study of birds" is called ornithology.
Scientists who study ornithology are called ornithologists.
Birds are endothermic vertebrates that have feathers and lay eggs. Birds are considered the only living direct descendants of dinosaurs. They belong to the taxonomic class Aves.
There are about 10,000 species of living bird known to science. Birds live in every habitat on Earth. They range in size from the Bee Hummingbird (Mellisuga helenae), the smallest living bird, to the Common Ostrich (Struthio camelus), which standing up to 8 feet (2.4 m) tall, is the tallest living bird.
Def. the group containing the most recent common ancestor of archosaurs and lepidosaurs and all its descendants is called the Sauria.
Sauria may be a crowned-base grouping of diapsids. However, recent genomic studies and comprehensive studies in the fossil record suggest that turtles are closely related to archosaurs, not to parareptiles as previously thought.
External Resources:
- a world bird database.
Buried "beneath the dry, dusty plains of Central Argentina the fossilized bones of Argentavis magnificens, now the world's largest known flying bird. With a wingspan of twenty-five feet, and stretching eleven feet from the tip of its bill to the tip of its tail The giant bird, a new genus and species of teratorn (from the Greek teratos-, meaning wonder, and ornis, meaning bird), was discovered a few years ago by two well-known Argentinian paleontologists, Drs. Eduardo Tonni and Rosendo Pascual. Argentavis magnificens is the oldest known teratorn. It has been dated at between five and eight million years old, or from the late part of the Miocene epoch, on the basis of the fossil mammals found in the same deposits as the fossil bird. Fossils of these same species of mammals have been found at other sites in Argentina for which radiaometric dates are available."
# Dinosaurology
Def. the "branch of paleontology that focuses on studying dinosaurs" is called dinosaurology.
Usually allied with geology rather than biology, paleontology is the study of past life. Dinosaurology is the specific branch of paleontology that is the study of dinosaurs. Because birds are the living descendants of dinosaurs, ornithology might be considered a branch of dinosaurology.
Scientists who study dinosaurs are usually called paleontologists, but might also be called dinosaurologists.
The non-avian dinosaurs lived during the Mesozoic Era, the time period between roughly 252 and 65 million years ago. The first dinosaurs evolved about 225 million years ago, and all but the birds became extinct by the end of the Mesozoic Era.
Dinosaurologists, like other paleontologists need a good grounding in geology and anatomy, as well as whatever other fields their particular study may involve.
# Crocodylomorphology
Def. the study of the Crocodylomorpha is called crocodylomorphology.
# Archelosaurology
Def. the "study of the Archelosauria" is called archelosaurology.
The Archelosauria include the Crurotarsi and Pan-Testudines.
The Crurotarsi include the Archosauria.
The Pan-Testudines include the Testudinata (turtles and tortoises) and †Sauropterygia.
# Cheloniology
Def. the scientific study of turtles is called cheloniology.
Def. the scientific study of tortoises is called testudinology.
# Lepidosaurology
Def. a "taxonomic superorder – the scaled reptiles" is called the Lepidosauria.
Def. a "study of Lepidosauria" is called lepidosaurology.
# Saurology
Def. any "reptile of the order Squamata , usually having four legs, external ear openings, and movable eyelids " is called a lizard.
Def. a "study of lizards" is called saurology.
# Ophiology
Def. the "study of snakes"is called ophiology.
Ophiology is a specialization of herpetology. Scientists who study ophiology are called herpetologists.
The name of this specialty comes from the Greek word for snake, ophis.
# Herpetology
Def. the "branch of biology dealing with reptiles (Reptilia) and amphibians" is called herpetology.
Scientists who study herpetology are called herpetologists.
Reptiles and amphibians are ectothermic vertebrates that have scales or naked skin. Reptiles lay shelled eggs or give birth to live young. Amphibians lay eggs without shells.
There are more than 10,000 species of reptile.
Reptiles also live in every terrestrial habitat on Earth except the artic and antarctic, but some species also occur in marine environments. Reptiles comprise the taxonomic class Reptilia. The living reptiles include lizards, snakes, tuataras, crocodilians, and turtles.
External Resources:
# Batrachology
Def. the "study of amphibians" is called batrachology.
Batrachology is a specialty within herpetology. Scientists who study Batrachology are called herpetologists.
The name of this specialty comes from the Ancient Greek word for frog, batrakhos.
There are about 8000 species of living amphibian known to science.
Amphibians live in every terrestrial habitat on Earth except in the arctic and antarctic. Amphibians are also absent from marine environments. The amphibians comprise the taxonomic class Amphibia. The living amphibians include frogs and toads, salamanders and newts, and caecilians.
Def. a "taxonomic within the superclass Tetrapoda – the reptile-like amphibians, which gave rise to the amniotes in the Carboniferous" is called the Reptiliomorpha.
# Ichthyology
Def. "the study of fish" is called ichthyology.
Scientists who study ichthyology are called ichthyologists.
Fishes are endothermic vertebrates that live in the fresh or marine water.
Living species are extremely diverse, and belong to three taxonomic groups, Superclass Agnatha (jawless fishes), Class Chondrichthyes (sharks and rays), and the Osteichthyes (the bony fishes).
There are about 30,000 species of living fish known to science. Fish live in every aquatic habitat on Earth.
About the Photo: Considered a "living fossil" because it is an ancient class of lobe-limbed fish that otherwise went extinct more than 70 million years ago, the first living coelacanth was caught off the east coast of South Africa near the Chalumna River in 1938. Today, at least two major populations of coelacanths are known: one off east Africa, and another near Indonesia. Coelacanths cannot be eaten; their flesh contains an oil that is highly distasteful to human beings. This specimen in the image above weighs 160 pounds (72.6 kg) and measures 5.5 feet (1.67 m) in length.
See also:
Fish
External Resources:
- at the Florida Museum, part of the University of Florida.
# Invertebrate Zoology
Invertebrate zoology is the study of animals that lack a spinal column. This covers approximately 97% of all known living species.
# Echinodermology
Def. study of the echinoderms is called echinodermology.
Echinodermology is a specialty of invertebrate zoology that studies echinoderms. The echinoderms include sea stars, urchins, and crinoids. All species are marine, so this is also a specialty of marine biology. Scientists who study echinoderms most often are called either marine biologists or invertebrate zoologists.
# Malacology
Def. a "soft-bodied invertebrate , " is called a mollusc.
Def. the "study of molluscs" is called malacology.
# Teuthology
Def. "the scientific study of squid (often extended to all cephalopods)" is called teuthology.
# Arthropodology
Def. the "study of arthropods" is called arthropodology.
The Arthropoda include the Chelicerata, Crustacea, Hexapoda, Myriapoda, †Marrellomorpha and the †Trilobitomorpha.
The classes of the Arthropoda include the Arachnida, Branchiopoda, Cephalocarida, Chilopoda, Diplopoda, Entognatha, Insecta, Malacostraca, Maxillopoda, Merostomata, Ostracoda, Pauropoda, Pycnogonida, Remipedia and Symphyla.
# Chelicerata
The Chelicerata contains the classes: Arachnida, Merostomata, Pycnogonida, †Aglaspidida, †Chasmataspidida, and †Eurypterida.
The subphylum Chelicerata constitutes one of the major subdivisions of the phylum Arthropoda that contains the sea spiders, arachnids (including scorpions, spiders, and potentially horseshoe crabs), and several extinct lineages, such as the eurypterids.
# Arachnology
Arachnology is the study of spiders, scorpions, and related arthropods. Scientists who study arachnology are called arachnologists.
Def. the "study of the Arachnida" is called arachnology.
# Arachnida
The Arachnida include the following orders (Ordines): Amblypygi, Araneae, †Haptopoda, Holothyrida, Ixodida, Mesostigmata, Opilioacarida, Opiliones, Palpigradi, †Phalangiotarbida, Pseudoscorpiones, Ricinulei, Sarcoptiformes, Schizomida, Scorpiones, Solifugae, Thelyphonida, †Trigonotarbida, Trombidiformes, †Uraraneida.
# Acarology
Def. the "study of ticks and mites" is called acarology.
"The 6 ordines Holothyrida, Ixodida, Mesostigmata, Opilioacarida, Sarcoptiformes and Trombidiformes are sometimes grouped together as Acari, but there is no consensus on classification above ordinal level, making a Linnean classification difficult."
# Araneology
Def. the "study of the spider, a branch of arachnology" is called araneology.
# Scorpiology
Def. the "scientific study of scorpions" is called scorpiology.
The order (Ordo) is Scorpiones.
# Xiphosurology
Xiphosura is an order of arthropods related to arachnids, or, according to one recent study, actual arachnids, sometimes called horseshoe crabs (a name applied more specifically to the only extant family, Limulidae).
Def. the study of the Merostomata, or Xiphosura, is called Xiphosurology.
# Pantopodology
Def. the study of the Pycnogonida is called pantopodology.
# Carcinology
Def. the "study of crustaceans" is called carcinology.
# Crustacea
The Crustacea contain the classes: Branchiopoda, Cephalocarida, Hexanauplia, Ichthyostraca, Malacostraca, Maxillopoda, Ostracoda and Remipedia.
# Branchiopodology
Def. the study of Branchiopoda is called branchiopodology.
# Brachypodology
The Cephalocarida are a class in the subphylum Crustacea comprising only 12 benthic species discovered in 1955 by Howard L. Sanders, and are commonly referred to as horseshoe shrimps.
Def. the study of the Brachypoda is called brachypodology.
# Malacostracology
Def. the study of the Malacostraca is called Malacostracology.
# Maxillopodology
Def. the study of the Maxillopoda is called maxillopodology.
Maxillopoda is a diverse class of crustaceans including barnacles, copepods and a number of related animals that does not appear to be a monophyletic group, and no single character unites all the members.
# Ostracodology
Def. the study of the Ostracoda is called ostracodology.
# Remipediology
Def. the study of the Remipedia is called remipediology.
# Hexapoda
The Hexapoda consist of the following classes: Entognatha and Insecta.
"Phylogenetic tree of Hexapoda . Hexapoda (insects and their six-legged relatives) comprise more than half of all described species and dominate terrestrial and freshwater ecosystems. The tree shown is from a maximum likelihood analysis of 8 genes, calibrated by 89 fossils. Membership of major clades is denoted by coloration of the ring (grey: Entognatha, black: basal insects, cyan: Palaeoptera, magenta: Polyneoptera, green: Paraneoptera, red: Holometabola). Changes in branch coloration denote diversification shifts identified using TurboMEDUSA. Branch colors identify regions of the tree with the same underlying diversification model. Symbols at shifts denote a net upshift (diamond) or down shift (circle). Coloration of symbols reflects the robustness of the shift event across 500-scaled samples taken from the post-burin MCMC chain (black: shift recovered in >80% of samples, grey with black outline: recovery >50%, grey with pale outline: recovery >30%, pale grey: recovery<30%). Black rings are shown at 100 Ma increments from the present."
# Entognathology
Def. the study of the Entognatha is called entognathology.
# Entomology
Entomology is the study of insects (Insecta). Scientists who study entomology are called entomologists.
Def. the "scientific study of insects" is called entomology.
The orders (Ordines) for the Insecta include: Archaeognatha, "Blattodea", Coleoptera, Dermaptera, Diptera, Embiidina, Ephemeroptera, Hemiptera, Hymenoptera, Isoptera, Lepidoptera, Mantodea, "Mecoptera", Megaloptera, Neuroptera, Notoptera, Odonata, Orthoptera, Phasmatodea, Phthiraptera, Plecoptera, "Psocoptera", Raphidioptera, Siphonaptera, Strepsiptera, Thysanoptera, Trichoptera, Zoraptera, and Zygentoma.
# Coleopterology
Def. the "scientific study of beetles" is called coleopterology.
# Lepidopterology
Def. the "scientific study of butterflies and moths" is called lepidopterology.
On the right is an example of Callioratis grandis from Mulanje Mountain, Africa.
Lepidopterology is the study of the Lepidoptera, the group of insects that includes butterflies and moths. It is a specialty of entomology, which is the overall study of insects. Most scientists who study the lepidoptera consider themselves to be entomologists.
# Myrmecology
Def. the "study of ants" is called myrmecology.
# Myriapodology
Def. the "scientific study of myriapods" is called myriapodology.
# Myriapoda
The Myriapoda include the classes: Chilopoda, Diplopoda, Pauropoda, Symphyla, and †Arthropleuridea.
# Chilopodology
Def. the study of the Chilopoda is called chilopodology.
Most centipedes are generally venomous and could inflict a painful bite, injecting their venom through pincer-like appendage known as forcipules, where despite the name, centipedes can have a varying number of legs, ranging from 30 to 354 and centipedes always have an odd number of pairs of legs. Therefore, no centipede has exactly 100 legs. Similar to spiders and scorpions, centipedes are predominantly carnivorous.
# Diplopodology
Def. the study of the Diplopoda is called diplopodology.
# Pauropodology
Def. the study of the Pauropoda is called pauropodology.
# Symphylology
Def. the study of the Symphyla is called symphylology.
# Arthropleurideology
Def. the study of the †Arthropleuridea is called arthropleurideology.
# †Marrellomorpha
Marrellomorphs are a group of arthropods known from the Cambrian to the Early Devonian.
# †Trilobitomorpha
Trilobites meaning "three lobes" are a group of extinct marine arachnomorph arthropods that form the class Trilobita. The trilobites were among the most successful of all early animals, existing in oceans for almost 300 million years.
Trilobites are often placed within the arthropod subphylum Schizoramia within the superclass Arachnomorpha (equivalent to the Arachnata), although several alternative taxonomies are found in the literature.
Trilobites had many lifestyles; some moved over the sea bed as predators, scavengers, or filter feeders, and some swam, feeding on plankton; lifestyles expected of modern marine arthropods are seen in trilobites, with the possible exception of parasitism (where scientific debate continues). Some trilobites (particularly the family Olenidae) are even thought to have evolved a symbiotic relationship with sulfur-eating bacteria from which they derived food.
# Trilobitology
Def. the "study of trilobites" is called trilobitology.
# Annelida
The earliest indisputable fossils of the Annelida appear in the Tertiary period, which began 66 million years ago.
There are over 22,000 living annelid species, ranging in size from microscopic to the Australian giant Gippsland earthworm and Amynthas mekongianus (Cognetti, 1922), which can both grow up to 3 meters long. Although research since 1997 has radically changed scientists' views about the evolutionary family tree of the annelids, most textbooks use the traditional classification into the following sub-groups:
- Polychaetes (about 12,000 species). As their name suggests, they have multiple chetae ("hairs") per segment. Polychaetes have parapodia that function as limbs, and nuchal organs that are thought to be chemosensors. Most are marine animals, although a few species live in fresh water and even fewer on land.
- Clitellates (about 10,000 species ). These have few or no chetae per segment, and no nuchal organs or parapodia. However, they have a unique reproductive organ, the ring-shaped clitellum ("pack saddle") around their bodies, which produces a pupa (cocoon) that stores and nourishes fertilized eggs until they hatch or, in moniligastrids, yolky eggs that provide nutrition for the embryos. The clitellates are sub-divided into:
Oligochaetes ("with few hairs"), which includes earthworms. Oligochaetes have a sticky pad in the roof of the mouth. Most are burrowers that feed on wholly or partly decomposed organic materials.
Hirudinea, whose name means "leech-shaped" and whose best known members are leeches. Marine species are mostly blood-sucking parasites, mainly on fish, while most freshwater species are predators. They have suckers at both ends of their bodies, and use these to move rather like inchworms.
- Oligochaetes ("with few hairs"), which includes earthworms. Oligochaetes have a sticky pad in the roof of the mouth. Most are burrowers that feed on wholly or partly decomposed organic materials.
- Hirudinea, whose name means "leech-shaped" and whose best known members are leeches. Marine species are mostly blood-sucking parasites, mainly on fish, while most freshwater species are predators. They have suckers at both ends of their bodies, and use these to move rather like inchworms.
The Archiannelida, minute annelids that live in the spaces between grains of marine sediment, were treated as a separate class because of their simple body structure, but are now regarded as polychaetes. Some other groups of animals have been classified in various ways, but are now widely regarded as annelids:
- Pogonophora / Siboglinidae were first discovered in 1914, and their lack of a recognizable gut made it difficult to classify them. They have been classified as a separate phylum, Pogonophora, or as two phyla, Pogonophora and Vestimentifera. More recently they have been re-classified as a family, Siboglinidae, within the polychaetes.
- The Echiura have a checkered taxonomic history: in the 19th century they were assigned to the phylum "Gephyrea", which is now empty as its members have been assigned to other phyla; the Echiura were next regarded as annelids until the 1940s, when they were classified as a phylum in their own right; but a molecular phylogenetics analysis in 1997 concluded that echiurans are annelids.
- Myzostomida live on crinoids and other echinoderms, mainly as parasites. In the past they have been regarded as close relatives of the trematode flatworms or of the tardigrades, but in 1998 it was suggested that they are a sub-group of polychaetes. However, another analysis in 2002 suggested that myzostomids are more closely related to flatworms or to rotifers and acanthocephales.
- Sipuncula was originally classified as annelids, despite the complete lack of segmentation, bristles and other annelid characters. The phylum Sipuncula was later allied with the Mollusca, mostly on the basis of developmental and larval characters. Phylogenetic analyses based on 79 ribosomal proteins indicated a position of Sipuncula within Annelida. Subsequent analysis of the mitochondrion's DNA has confirmed their close relationship to the Myzostomida and Annelida (including echiurans and Siboglinidae (pogonophorans). It has also been shown that a rudimentary neural segmentation similar to that of annelids occurs in the early larval stage, even if these traits are absent in the adults.
On the right, "This is a parchment worm (Thelepus cincinatus) that is out of its tube. It is also called a Bristleworm and puts out its tentacles to collect its microscopic food."
# Brachiopodology
Def. the study of the Brachiopoda is called brachiopodology.
Lineages of brachiopods that have both fossil and extant taxa appeared in the early Cambrian, Ordovician, and Carboniferous periods, respectively.
The largest brachiopods known – Gigantoproductus and Titanaria, reaching 30 to 38 cm in width – occurred in the upper part of the Lower Carboniferous.
Brachiopod shells can be classified according to the angle between the cardinal plane and the plane where the shells join (commissure); anacline shells have an angle of less than 90°, whereas aspacline shells have a higher angle.
Impunctate shells as solid without any tissue inside them, and pseudopunctate shells are only known from fossil forms.
# Bryozoology
Def. a "branch of zoology specializing in Bryozoa" is called bryozoology.
# Chaetognatha
The Chaetognatha fossil range is Lower Cambrian to Recent.
There are more than 120 modern species assigned to over 20 genera. Despite the limited diversity of species, the number of individuals is large.
All chaetognaths are carnivorous, preying on other planktonic animals.
Two chaetognath species, Caecosagitta macrocephala and Eukrohnia fowleri, have bioluminescent organs on their fins.
Chaetognaths swim in short bursts using a dorso-ventral undulating body motion, where their tail fin assists with propulsion and the body fins with stabilization and steering. Some species are known to use the neurotoxin tetrodotoxin to subdue prey.
# Cnidariology
Def. the study of the Cnidaria is called cnidariology.
Def. the study of the Myxozoa is called myxozoology.
Myxozoans were originally considered protozoan, and were included among other non-motile forms in the group Sporozoa. As their distinct nature became clear through 18S ribosomal DNA (rDNA) sequencing, they were relocated in the metazoa. Detailed classification within the metazoa was however long hindered by conflicting rDNA evidence: although 18S rDNA suggested an affinity with Cnidaria, other rDNA sampled, and the HOX genes of two species, were more similar to those of the Bilateria.
Further testing resolved the genetic conundrum by sourcing the first three previously identified discrepant HOX genes (Myx1-3) to the bryozoan Cristatella mucedo and the fourth (Myx4) to Northern pike, the respective hosts of the two corresponding Myxozoa samples. This explained the confusion: the original experiments had used samples contaminated by tissue from host organisms, leading to false positives for a position among the Bilateria. More careful cloning of 50 coding genes from Buddenbrockia firmly established the clade as severely modified members of the phylum Cnidaria, with medusozoans as their closest relatives. Similarities between myxozoan polar capsules and cnidarian nematocysts had been drawn for a long time, but were generally assumed to be the result of convergent evolution.
Taxonomists now recognize the outdated subgroup Actinosporea as a life-cycle phase of Myxosporea.
# Ctenophorology
Def. the study of the Ctenophora is called ctenophorology.
The Beroida, also known as Nuda, have no feeding appendages, but their large pharynx, just inside the large mouth and filling most of the saclike body, bears "macrocilia" at the oral end which are fused bundles of several thousand large cilia are able to "bite" off pieces of prey that are too large to swallow whole – almost always other ctenophores.
In front of the field of macrocilia, on the mouth "lips" in some species of Beroe, is a pair of narrow strips of adhesive epithelial cells on the stomach wall that "zip" the mouth shut when the animal is not feeding, by forming intercellular connections with the opposite adhesive strip, which streamlines the front of the animal when it is pursuing prey.
# Cycliophorology
Def. the study of the Cycliophora is called cycliophorology.
# Gastrotrichology
Def. the study of the Gastrotricha is called gastrotrichology.
As of 2011, around 790 species have been described. The phylum contains a single class, divided into two orders: the Macrodasyida and the Chaetonotida. The Macrodasyida are wholly marine, but two rare and poorly known species, Marinellina flagellata and Redudasys fornerise, are known from fresh water. The Chaetonotida comprise both marine and freshwater species.
Phylogenetics places the Gastrotricha as close relatives of the flatworms Platyhelminthes, the Ecdysozoa or the Lophotrochozoa.
# Gnathostomulidology
Def. the study of the Gnathostomulida is called gnathostomulidology.
The Gnathostomulida were first recognised and described in 1956.
In many Bursovaginoidea, one of the major group of gnathostomulids, the neck region is slightly narrower than the rest of the body, giving them a distinct head.
Like flatworms they have a ciliated epidermis, but in contrast to flatworms, they have one cilium per cell.
The only sense organs are modified cilia, which are especially common in the head region.
The basal plate is used to scrape smaller organisms off of the grains of sand that make up their anoxic seabed mud habitat.
The mouth opens into a blind-ending tube in which digestion takes place; there is no true anus. However, there is tissue connecting the intestine to the epidermis which may serve as an anal pore.
# Hemichordatology
Def. the study of the Hemichordata is called hemichordatology.
The extinct class Graptolithina is closely related to the pterobranchs.
Acorn worms are solitary worm-shaped organisms that generally live in burrows (the earliest secreted tubes).
While the family Torquaratoridae are free living detritivores, many are well known for their production and accumulation of various halogenated phenols and pyrroles. Pterobranchs are filter-feeders, mostly colonial, living in a collagenous tubular structure called a coenecium.
A post-anal tail is present in juvenile member of the acorn worm family Harrimaniidae.
# Kamptozoology
Def. the study of the Kamptozoa is called kamptozoology.
Entoprocta, coined in 1870, means "anus inside". The alternative name "Kamptozoa", meaning "bent" or "curved" animals, where the prefix "campto-" is explained was assigned in 1929. Some authors use Entoprocta while others prefer Kamptozoa.
Most species are colonial, and their members are known as "zooids", since they are not fully independent animals. Zooids are typically 1 mm long but range from 0.1 to 7 mm long.
# Kinorhynchology
Def. the study of the Kinorhyncha is called kinorhynchology.
Modern species of the Kinorhyncha are 1 mm or less, but Cambrian forms could reach 4 cm.
Unlike some similar invertebrates, they do not have external cilia, but instead have a number of spines along the body, plus up to seven circles of spines around the head.
The head is completely retractable, and is covered by a set of neck plates called placids when retracted. The short hind-gut is lined by cuticle, and empties into an anus at the posterior end of the trunk. The excretory system consists of two protonephridia emptying through pores in the final segment. Some species have simple ocelli on the head, and all species have tiny bristles on the body to provide a sense of touch.
# Loriciferology
Def. the study of the Loricifera is called loriciferology.
Loricifera is a phylum of very small to microscopic marine cycloneuralian sediment-dwelling animals with 37 described species, in nine genera. Aside from these described species, there are approximately 100 more that have been collected and not yet described. Their sizes range from 100 µm to ca. 1 mm. Their habitat is in the spaces between marine gravel to which they attach themselves. The phylum was discovered in 1983 by Reinhardt Kristensen, in Roscoff, France. They are among the most recently discovered groups of Metazoans. They attach themselves quite firmly to the substrate, and hence remained undiscovered for so long. The first specimen was collected in the 1970s, and later described in 1983. They are found at all depths, in different sediment types, and in all latitudes.
The armor-like lorica consists of a protective external shell or case of encircling plicae. Many of the larvae are acoelomate, with some adults being pseudocoelomate, and some remaining acoelomate.
Fossils have been dated to the late Cambrian.
Morphological studies have traditionally placed the phylum in the Vinctiplicata with the Priapulida; this plus the Kinorhyncha constitutes the taxon Scalidophora, or Cephalorhyncha, where the three phyla share four characters in common — chitinous cuticle, rings of scalids on the introvert, flosculi, and two rings of introvert retracts. However, mounting molecular evidence indicates a closer relationship with the Panarthropoda.
# Micrognathozoology
Def. the study of the Micrognathozoa is called micrognathozoology.
Limnognathia maerski is a microscopic platyzoan freshwater animal, discovered living in warm springs on Disko Island, Greenland in 1994, that has variously been assigned as a class or subphylum in the phylum Gnathifera or as a phylum in a Gnathifera superphylum, named Micrognathozoa, related to the rotifers and gnathostomulids, grouped together as the Gnathifera.
# Nematodology
Def. the study of the Nematoda is called nematodology.
The nematodes or roundworms constitute the phylum Nematoda, also called Nemathelminthes.
A 2013 survey of animal biodiversity published in the mega journal Zootaxa puts the number of species at over 25,000.
Nematods are found in every part of the earth's lithosphere, even at great depths, 0.9–3.6 km below the surface of the Earth in gold mines in South Africa. They represent 90% of all animals on the ocean floor. In total, 4.4 × 1020 nematodes inhabit the Earth's topsoil, or approximately 60 billion for each human, with the highest densities observed in tundra and boreal forests. Their numerical dominance, often exceeding a million individuals per square meter and accounting for about 80% of all individual animals on earth, their diversity of lifecycles, and their presence at various trophic levels point to an important role in many ecosystems. They have been shown to play crucial roles in polar ecosystem. The roughly 2,271 genera are placed in 256 families. The many parasitic forms include pathogens in most plants and animals. A third of the genera occur as parasites of vertebrates; about 35 nematode species occur in humans.
"In short, if all the matter in the universe except the nematodes were swept away, our world would still be dimly recognizable, and if, as disembodied spirits, we could then investigate it, we should find its mountains, hills, vales, rivers, lakes, and oceans represented by a film of nematodes. The location of towns would be decipherable, since for every massing of human beings, there would be a corresponding massing of certain nematodes. Trees would still stand in ghostly rows representing our streets and highways. The location of the various plants and animals would still be decipherable, and, had we sufficient knowledge, in many cases even their species could be determined by an examination of their erstwhile nematode parasites."
# Nematomorphology
Def. the study of the Nematomorpha is called nematomorphology.
The adult worms are free-living, but the larvae are parasitic on arthropods, such as beetles, cockroaches, mantids, orthopterans, and crustaceans. About 351 freshwater species are known and a conservative estimate suggests that there may be about 2000 freshwater species worldwide. The name "Gordian" stems from the legendary Gordian knot. This relates to the fact that nematomorpha often tie themselves in knots.
The nervous system consists of a nerve ring near the anterior end of the animal, and a ventral nerve cord running along the body.
# Nemerteology
Def. the study of the Nemertea is called nemerteology.
Nemertea is a phylum of invertebrate animals also known as ribbon worms or proboscis worms. Alternative names for the phylum have included Nemertini, Nemertinea and Rhynchocoela.
In 1995, a total of 1,149 species had been described and grouped into 250 genera.
Nemertea are named after the Greek sea-nymph Nemertes, one of the daughters of Nereus and Doris. Alternative names for the phylum have included Nemertini, Nemertinea, and Rhynchocoela. The Nemertodermatida are a separate phylum, whose closest relatives appear to be the Acoela.
# Onychophorology
Def. the study of the Onychophora is called onychophorology.
Onychophora, commonly known as velvet worms (due to their velvety texture and somewhat wormlike appearance) or more ambiguously as peripatus (after the first described genus, Peripatus), is a phylum of elongate, soft-bodied, many-legged panarthropods. In appearance they have variously been compared to worms with legs, caterpillars, and slugs.
"Because they resemble worms with legs ... Superficially they resemble caterpillars, but have also been compared with slugs."
It is the only phylum within Animalia that is wholly endemic to terrestrial environments. Velvet worms are considered close relatives of the Arthropoda and Tardigrada, with which they form the taxon Panarthropoda.
# Phoronidology
Def. the study of the Phoronida is called phoronidology.
Phoronis is the name of one of the two genera of Phoronids.
As of 2010 there are no indisputable body fossils of phoronids.
Phoronids may be members of the protostome super-phylum Lophotrochozoa.
Phoronids and brachiopods may be sister-groups, while others place phoronids as a sub-group within brachiopoda.
The diagram on the right describes the anatomy of an adult phoronid.
Most adult phoronids are 2 to 20 cm long and about 1.5 mm wide,
although the largest are 50 cm long. Their skins have no cuticle but secrete rigid tubes of chitin, similar to the material used in arthropods' exoskeletons, and sometimes reinforced with sediment particles and other debris. Most species' tubes are erect, but those of Phoronis vancouverensis are horizontal and tangled. Phoronids can move within their tubes but never leave them. The bottom end of the body is an ampulla (a flask-like swelling in a tube-like structure), which anchors the animal in the tube and enables it to retract its body when threatened, reducing the body to 20 percent of its maximum length. Longitudinal muscles retract the body very quickly, while circular muscles slowly extend the body by compressing the internal fluid.
For feeding and respiration each phoronid has at the top end a lophophore, a "crown" of tentacles with which the animal filter-feeds. In small species the "crown" is a simple circle, in medium-size species it is bent into the shape of a horseshoe with tentacles on the outer and inner sides, and in the largest species the ends of the horseshoe wind into complex spirals. These more elaborate shapes increase the area available for feeding and respiration. The tentacles are hollow, held upright by fluid pressure, and can be moved individually by muscles.
The mouth is inside the base of the crown of tentacles but to one side. The gut runs from the mouth to one side of the stomach, in the bottom of the ampulla. The intestine runs from the stomach, up the other side the body, and exits at the anus, outside and a little below the crown of tentacles. The gut and intestine are both supported by two mesenteries (partitions that run the length of the body) connected to the body wall, and another mesentery connects the gut to the intestine.
The body is divided into coeloms, compartments lined with mesothelium. The main body cavity, under the crown of tentacles, is called the metacoelom, and the tentacles and their base share the mesocoelom. Above the mouth is the epistome, a hollow lid which can close the mouth. The cavity in the epistome is sometimes called the protocoelom, although other authors disagree that it is a coelom and Ruppert, Fox and Barnes think it is built by a different process.
# Placozoology
Def. the study of the Placozoa is called placozoology.
The Placozoa are a basal form of free-living (non-parasitic) multicellular organism. They are the simplest in structure of all animals. Three genera have been found: the classical Trichoplax adhaerens, Hoilungia hongkongensis, and Polyplacotoma mediterranea, where the last appears most basal. The last two have been found only since 2017. Although the Placozoa were first discovered in 1883 and since the 1970s more systematically analyzed, a common name does not yet exist for the taxon; the scientific name means "flat animals".
# Platyhelminthology
Def. the study of the Platyhelminthes is called platyhelminthology.
Like other bilaterians, they have three main cell layers (endoderm, mesoderm, and ectoderm), while the radially symmetrical cnidarians and ctenophores (comb jellies) have only two cell layers. Beyond that, they are "defined more by what they do not have than by any particular series of specializations." Unlike other bilaterians, Platyhelminthes have no internal body cavity, so are described as acoelomates. They also lack specialized circulatory and respiratory organs, both of these facts are defining features when classifying a flatworm's anatomy. Their bodies are soft and unsegmented.
# Poriferology
Def. the study of the Porifera is called poriferology.
Def. a "branch of zoology concerning sponges or Porifera" is called spongiology.
# Rhombozoology
Def. the study of the Rhombozoa is called rhombozoology.
Classification is controversial. Traditionally, dicyemids have been grouped with the Orthonectida in the Mesozoa, and, as of 2017, molecular evidence appears to confirm this.
However, other molecular phylogenies have placed the dicyemids more closely related to the Nematoda (roundworms). Additional molecular evidence suggests that this phylum is derived from the Lophotrochozoa.
The phylum is not divided in classes or orders, but contains three families, Conocyemidae, Dicyemidae, and Kantharellidae.
# Rotiferology
Def. the study of the Rotifera is called rotiferology.
Def. any "of many minute aquatic multicellular organisms, of the phylum Rotifera, that have a ring of cilia resembling a wheel" is called a rotifer.
# Scalidophorology
Def. the study of the Scalidophora is called scalidophorology.
Scalidophora is a group of marine pseudocoelomate protostomes that was proposed on morphological grounds to unite three phyla: the Kinorhyncha, the Priapulida and the Loricifera. The three phyla have four characters in common — chitinous cuticle that is moulted, rings of scalids on the introvert, flosculi, and two rings of introvert retracts. However, the monophyly of the Scalidophora is not supported by molecular studies, where the position of the Loricifera was uncertain or as sister to the Panarthropoda.
The group has also been considered a single group, Cephalorhyncha, with three classes.
The group is named after the spines (scalids) covering the introvert (head that can be retracted into the trunk).
# Sipunculology
Def. the study of the Sipuncula is called sipunculology.
The worm Sipunculus nudus was first described in 1767. In 1814, the word "Sipuncula" was used to describe the family (now Sipunculidae), and in time, the term came to be used for the whole phylum. This is a relatively understudied group, and it is estimated there may be around 162 species worldwide.
The phylogenetic placement of this phylum in the past has proved troublesome. Originally classified as annelids, despite the complete lack of segmentation, bristles and other annelid characters, the phylum Sipuncula was later allied with the Mollusca, mostly on the basis of developmental and larval characters. Currently these two phyla have been included in a larger group, the Lophotrochozoa, that also includes the annelids, the nemertea (ribbon worms) and several other phyla. Phylogenetic analyses based on 79 ribosomal proteins indicated a position of Sipuncula within Annelida. Subsequent analysis of the mitochondrion's DNA has confirmed their close relationship to the Myzostomida and Annelida (including echiurans and Siboglinidae (pogonophorans)). It has also been shown that a rudimentary neural segmentation similar to that of annelids occurs in the early larval stage, even if these traits are absent in the adults.
# Tardigradology
Def. the study of the Tardigrada is called tardigradology.
Tardigrades, known colloquially as water bears or moss piglets, are a phylum of water-dwelling eight-legged segmented micro-animals. They were first described by the German zoologist Johann August Ephraim Goeze in 1773, who called them little water bears. In 1777, the Italian biologist Lazzaro Spallanzani named them Tardigrada, which means "slow steppers".
They have been found everywhere, from mountaintops to the deep sea and mud volcanoes, and from tropical rain forests to the Antarctic. Tardigrades are among the most resilient animals known, with individual species able to survive extreme conditions—such as exposure to extreme temperatures, extreme pressures (both high and low), air deprivation, radiation, dehydration, and starvation—that would quickly kill most other known forms of life. Tardigrades have survived exposure to outer space. About 1,150 known species form the phylum Tardigrada, a part of the superphylum Ecdysozoa. The group includes fossils dating from 530 million years ago, in the Cambrian period.
Tardigrades are usually about 0.5 mm long when fully grown. They are short and plump, with four pairs of legs, each ending in claws (usually four to eight) or sucking disks. Tardigrades are prevalent in mosses and lichens and feed on plant cells, algae, and small invertebrates. When collected, they may be viewed under a very low-power microscope, making them accessible to students and amateur scientists.
# Xenacoelomorphology
Def. the study of the Xenacoelomorpha is called xenacoelomorphology.
Xenacoelomorpha is a basal bilaterian phylum of small and very simple animals, grouping the xenoturbellids with the acoelomorphs. This grouping was suggested by morphological synapomorphies, and confirmed by phylogenomic analyses of molecular data.
The clade Xenacoelomorpha, grouping Acoelomorpha and the genus Xenoturbella, was revealed by molecular studies. Initially it was considered to be a member of the deuterostomes, but a more recent transcriptome analysis concluded that it is the sister group to the Nephrozoa, which includes the protostomes and the deuterostomes, being therefore the basalmost bilaterian clade.
# Systematics & Taxonomy
Superregnum: Eukaryota
Systematics is the study of the evolutionary relationships among organisms. It includes taxonomy, which is the study of the names of organisms and their organization into categories. Scientists who study systematics are called systematists, while taxonomists primarily study taxonomy. Most systematists are also taxonomists.
Living organisms are grouped into a hierarchy of categories. The main categories are Kingdom (or Regnum, pl. Regna), Phylum (pl. Phyla), Class, Order, Family, Genus (pl. Genera), and Species (pl. Species). Every living organism is classified into one, and only one, of each of those categories. There are additional categories used for some groups, but not all.
The classification of organisms can change as more is learned about the living world around us.
Below are two ideas of how life may be divided into Kingdoms (Regna).
- Four Regna listed by Whittaker & Margulis (1978): Animalia - Plantae - Fungi - Protista
- Five Regna listed Cavalier-Smith (1981): Animalia - Plantae - Fungi - Chromista - Protozoa
Below is one recent list of the Phyla of within the Kingdom Animalia. Note number 8, Chordata. That is the Phylum that includes vertebrates, the animals with a spinal column that includes humans.
Regnum: Animalia
Phyla (36):
- Acanthocephala
- Annelida
- Arthropoda
- Brachiopoda
- Bryozoa
- Cephalorhyncha
- Chaetognatha
- Chordata
- Cnidaria
- Ctenophora
- Cycliophora
- Echinodermata
- Echiura
- Gastrotricha
- Gnathostomulida
- Hemichordata
- Kamptozoa
- Kinorhyncha
- Loricifera
- Micrognathozoa
- Mollusca
- Nematoda
- Nematomorpha
- Nemertea
- Onychophora
- Orthonectida
- Phoronida
- Placozoa
- Platyhelminthes
- Porifera
- Rhombozoa
- Rotifera
- Sipuncula
- Tardigrada
- Xenacoelomorpha
# Parasitology
"Humans are hosts to nearly 300 species of parasitic worms and over 70 species of protozoa, some derived from our primate ancestors and some acquired from the animals we have domesticated or come in contact with during our relatively short history on Earth".
Parasitology is the study of parasites. In this context, a parasite is usually an invertebrate, and as such parasitology is a specialization of invertebrate zoology. Scientists that study parasites are called parasitologists.
Parasites are organisms that live on or in, and take their nutrition from, another living organism called a host. Rarely do parasites kill their hosts, since finding a new host can be quite difficult. Individual parasites may do little harm to their host, but large numbers of them can cause great problems. This kind of relationship where one organism lives off another giving either nothing in return or causing harm is called parasitism.
Parasites may be found in many invertebrate taxonomic groups. Commonly encountered parasites include tapeworms, roundworms, and lice.
# Helminthology
Def. the "branch of zoology related to the study of helminths (parasitic worms)" is called helminthology.
# Acanthocephalology
Def. the study of the Acanthocephala is called acanthocephalology.
The "Acanthocephala are descended from, and should be considered as, highly modified rotifers. Genetic research has determined this is unequivocal; the Acanthocephalans are modified rotifers".
Acanthocephalans have complex life cycles, involving at least two hosts, which may include invertebrates, fish, amphibians, birds, and mammals. About 1420 species have been described.
# Orthonectidology
Def. the study of the Orthonectida is called orthonectidology.
Orthonectida is a small phylum of poorly known parasites of marine invertebrates.
The adults are microscopic wormlike animals, consisting of a single layer of ciliated outer cells surrounding a mass of sex cells, that swim freely within the bodies of their hosts, which include flatworms, polychaete worms, bivalve molluscs, and echinoderms, and are gonochoristic, with separate male and female individuals.
When they are ready to reproduce, the adults leave the host, and sperm from the males penetrate the bodies of the females to achieve internal fertilisation, where the resulting zygote develops into a ciliated larva that escapes from the mother to seek out new hosts so as to lose its cilia and develop into a syncytial plasmodium larva, which, in turn, breaks up into numerous individual cells that become the next generation of adults.
# Hypotheses
An hypothesis is a scientific statement made to explain some part of the world. It is not a guess. It is testable by scientific means, and is falsifiable (able to be disproved) by those means. Coming up with hypotheses and testing them are the main occupation of science.
- The genetic classification of animals may not match the current classification before genetic evidence.
# Acknowledgements
The content on this page was first contributed by: Henry A. Hoff.
Initial content for this page in some instances came from Wikiversity. | Zoology
Editor-In-Chief Henry A. Hoff
Template:TOCright
Zoology is a biological science that pertains to animals. Animals choose to move whereas plants are moved. Animals feed on bio-organic material and digest it internally. Plants can convert inorganic and organic material into bio-organic material. Cell walls of an animal are flexible. Animal cells possess junctions which are impermeable to fluids (tight junctions), junctions which allow intercellular communication, or the transfer of low molecular-weight substances (gap junctions), and structures which adhere to other cells to form tissue via structural units (desmosomes).
# Genetics
Genetics is the study of the genes, how they affect organisms, and how they are passed from one generation to the next. A scientist that studies genetics is called a geneticist.
Def. a "branch of biology that deals with the transmission and variation of inherited characteristics,[1] in particular chromosomes and DNA"[2] is called genetics.
DNA, deoxyribonucleic acid, is a molecule found in almost every cell of every body of every organism. DNA contains genes, which are the basic instruction codes for making and running a living organism. Strands of DNA make up chromosomes. (Chromosomes are made of DNA, which is made up of genes.)
Genes, through DNA and chromosomes, are passed from one generation to the next by inheritance. Because of this, offspring resemble their parents. Through mixing and occasional mutation, genes can change. When genes change, how the organism forms and how it works may be changed.
How all these changes affect individuals, populations, and entire species is the work of geneticists.
______
"A recent comparison of the draft sequences of mouse and human genomes has shed light on the selective forces that have predominated in their recent evolutionary histories. In particular, mouse-specific clusters of homologues associated with roles in reproduction, immunity and host defence appear to be under diversifying positive selective pressure, as indicated by high ratios of non-synonymous to synonymous substitution rates. These clusters are also frequently punctuated by homologous pseudogenes. They thus have experienced numerous gene death, as well as gene birth, events. These regions appear, therefore, to have borne the brunt of adaptive evolution that underlies physiological and behavioural innovation in mice. We predict that the availability of numerous animal genomes will give rise to a new field of genome zoology in which differences in animal physiology and ethology are illuminated by the study of genomic sequence variations."[3]
# Biology
Def. the "study of all life or living matter"[4] is called biology.
On the right is a drawing of the archaean Haloquadratum walsbyi.
As the study of biology is the study of all living organisms, zoology is a specialty of biology. All zoologists are also considered biologists.
Other branches of biology include botany (the study of plants), mycology (the study of fungi), phycology (the study of algae), and virology (the study of viruses).
# Animals
The biological definition of animals includes all members of the kingdom Animalia.[5]
Def. "a multicellular organism that is usually mobile, whose cells are not encased in a rigid cell wall (distinguishing it from plants and fungi) and which derives energy solely from the consumption of other organisms"[6] is called an animal.
In colloquial use, as a consequence of anthropocentrism, the term animal is sometimes used nonscientifically to refer only to non-human animals.[7][8][9][10]
Animals are eukaryotic and multicellular,[11][12] unlike bacteria, which are prokaryotic, and unlike protists, which are eukaryotic but unicellular. Unlike plants and algae, which are autotrophs, producing their own nutrients[13] animals are heterotrophic,[12][14] feeding on organic material and digesting it internally.[15] With very few exceptions, animals breathe oxygen and respire aerobically.[16] All animals are motile[17] (able to spontaneously move their bodies) during at least part of their life cycle, but some animals, such as sponges, corals, mussels, and barnacles, later become sessile. The blastula is a stage in embryogenesis, embryonic development, that is unique to most animals,[18] allowing cells to be differentiated into specialised tissues and organs.
All animals are composed of cells, surrounded by a characteristic extracellular matrix composed of collagen and elastic glycoproteins.[19] During development, the animal extracellular matrix forms a relatively flexible framework upon which cells can move about and be reorganised, making the formation of complex structures possible. This may be calcified, forming structures such as an exoskeleton of shells, bones, and spicules.[20] In contrast, the cells of other multicellular organisms (primarily algae, plants, and fungi) are held in place by cell walls, and so develop by progressive growth.[21] Animal cells uniquely possess the cell junctions called tight junctions, gap junctions, and desmosomes.[22]
With few exceptions—in particular, the sponges and placozoans—animal bodies are differentiated into tissues.[23] These include muscles, which enable locomotion, and nerve tissues, which transmit signals and coordinate the body. Typically, there is also an internal digestive chamber with either one opening (as in flatworms) or two openings (as in deuterostomes).[24]
Nearly all animals make use of some form of sexual reproduction.[25] They produce haploid gametes by meiosis; the smaller, motile gametes are spermatozoa and the larger, non-motile gametes are ova.[26] These fuse to form zygotes,[27] which develop via mitosis into a hollow sphere, called a blastula. In sponges, blastula larvae swim to a new location, attach to the seabed, and develop into a new sponge.[28] In most other groups, the blastula undergoes more complicated rearrangement.[29] It first invaginates to form a gastrula with a digestive chamber and two separate germ layers, an external ectoderm and an internal endoderm.[30] In most cases, a third germ layer, the mesoderm, also develops between them.[31] These germ layers then differentiate to form tissues and organs.[32]
Repeated instances of inbreeding, mating with a close relative, during sexual reproduction generally leads to inbreeding depression within a population due to the increased prevalence of harmful recessive traits.[33][34] Animals have evolved numerous mechanisms for inbreeding avoidance, or avoiding close inbreeding.[35] In some species, such as the splendid fairywren (Malurus splendens), females benefit by mating with multiple males, thus producing more offspring of higher genetic quality.[36]
Some animals are capable of asexual reproduction, which often results in a genetic clone of the parent. This may take place through fragmentation; budding, such as in Hydra and other cnidarians; or parthenogenesis, where fertile eggs are produced without mating, such as in aphids.[37][38]
Animals are categorised into ecological groups depending on how they obtain or consume organic material, including carnivores, herbivores, omnivores, detritivores,[39] and parasites.[40] Interactions between animals form complex food webs. In carnivorous or omnivorous species, predation is a consumer-resource interaction where a predator feeds on another organism (called its prey).[41] Selective pressures imposed on one another lead to an evolutionary arms race between predator and prey, resulting in various anti-predator adaptations.[42][43] Almost all multicellular predators are animals.[44] Some consumers use multiple methods; for example, in parasitoid wasps, the larvae feed on the hosts' living tissues, killing them in the process,[45] but the adults primarily consume nectar from flowers.[46] Other animals may have very specific feeding behaviours, such as hawksbill sea turtles that primarily eat sponges.[47]
Most animals rely on the energy produced by plants through photosynthesis. Herbivores eat plant material directly, while carnivores, and other animals on higher trophic levels, typically acquire energy (in the form of reduced carbon) by eating other animals. The carbohydrates, lipids, proteins, and other biomolecules are broken down to allow the animal to grow and to sustain biological processes such as locomotion.[48][49][50] Animals living close to hydrothermal vents and cold seeps on the dark sea floor do not depend on the energy of sunlight.[51] Rather, archaea and bacteria in these locations produce organic matter through chemosynthesis (by oxidizing inorganic compounds, such as methane) and form the base of the local food web.[52]
Animals originally evolved in the sea. Lineages of arthropods colonised land around the same time as land plants, probably between 510–471 million years ago during the Late Cambrian or Early Ordovician.[53] Vertebrates such as the Sarcopterygii, lobe-finned fish, Tiktaalik started to move on to land in the late Devonian, about 375 million years ago.[54][55] Animals occupy virtually all of earth's habitats and microhabitats, including salt water, hydrothermal vents, fresh water, hot springs, swamps, forests, pastures, deserts, air, and the interiors of animals, plants, fungi and rocks.[56] Animals are however not particularly heat tolerant; very few of them can survive at constant temperatures above 50 °C.[57] Only very few species of animals (mostly nematodes) inhabit the most extreme cold deserts of continental Antarctica.[58]
# Theoretical zoology
Def. "that part of biology which relates to the animal kingdom, including the structure, embryology, evolution, classification, habits, and distribution of all animals, both living and extinct"[59] is called zoology.
"Compare both photos, in the photo above and the "civil war soldiers". All this is model of a pterodactyl. Not sure of the age, but I'm sure it was like a practical joke back in the day. The "bigfoot" of it's day so to speak. Compare the photos and you'll see that it's the exact same model. The above photo would be a better looking fake than the civil war photo. Any real dead animal is limp until rigor sets in, and even then, it has to [weigh] something right? Why is the guy in the center of the above photo not holding up the main weight of the body? He's practically leaning on it. It's because it's a stiff model that supports itself. And I'm willing to bet that if you were to look at some older photos around the turn of the 19th century of some paleontology exhibits, you'd find this exact same model at some point. The Bone Wars started in the 1880s and made dinosaurs all the rage."[60]
# Zoography
Zoography is descriptive zoology. Animals are described in comparison with other organisms, and their surroundings. This comparison takes into account variation among individuals and populations, and organizes it into systems and classifications that are used for making predictions, such as the evolutionary relationships among organisms.
The branches of zoology focusing on a particular taxonomic group (mammals, etc.) are often considered part of zoography.
Def. a "description of animals, their forms, and habits; descriptive zoology"[61] is called zoography.
# Vertebrate Zoology
Vertebrate zoology is the study of vertebrates, the animals that have a spinal column. This covers only about 3% of all known species.
# Mammalogy
Def. the "study of mammals"[62] is called mammalogy.
Scientists who study mammalogy are called mammalogists.
Mammals are endothermic vertebrates that have fur or hair and feed milk to their young. Milk is a fluid produced by mammary glands.
There are about 5000 species of living mammal known to science. Mammals live in every habitat on Earth. They range in size from the Etruscan shrew (Suncus etruscus), the smallest living mammal, to the blue whale (Balaenoptera musculus) which is the largest animal to have ever lived. Humans (Homo sapiens) are also mammals. They are placed in the taxonomic class Mammalia.
Def. a "taxonomic subclass within the class Reptilia – (or a class or clade within superclass Tetrapoda) - the extinct “mammal-like” reptiles [and the mammals][63]"[64] is called the Synapsida.
Def. a "taxonomic clade within the clade Reptiliomorpha – the most recent common ancestor of extant mammals and reptiles, and all its descendants; the reptiles, birds and mammals, collectively, all of which have an amnion during development[65]"[66] is called the Amniota.
External Resources:
- [American Society of Mammalogists]
- [Mammalian Species] a journal that consists of species accounts of mammals from around the world.
# Archosaurology
Def. the study of the Archosauria is called archosaurology.
The Archosauria include the Pseudosuchia and the Ornithodira.
The Pseudosuchia include the Crocodylomorpha: Crocodylia, †Aetosauria, †Phytosauria, †Rauisuchia and the unplaced families: †Atoposauridae, †Bernissartiidae, and †Peirosauridae.
The Ornithodira include the Dinosauromorpha and †Pterosauromorpha.
The Dinosauromorpha include the Dinosauria.
# Ornithology
Def. "the scientific study of birds"[67] is called ornithology.
Scientists who study ornithology are called ornithologists.
Birds are endothermic vertebrates that have feathers and lay eggs. Birds are considered the only living direct descendants of dinosaurs. They belong to the taxonomic class Aves.
There are about 10,000 species of living bird known to science. Birds live in every habitat on Earth. They range in size from the Bee Hummingbird (Mellisuga helenae), the smallest living bird, to the Common Ostrich (Struthio camelus), which standing up to 8 feet (2.4 m) tall, is the tallest living bird.
Def. the group containing the most recent common ancestor of archosaurs and lepidosaurs and all its descendants[68] is called the Sauria.
Sauria may be a crowned-base grouping of diapsids.[69] However, recent genomic studies[70][71][72] and comprehensive studies in the fossil record[73] suggest that turtles are closely related to archosaurs, not to parareptiles as previously thought.
External Resources:
- [Avibase] a world bird database.
Buried "beneath the dry, dusty plains of Central Argentina [was] the fossilized bones of Argentavis magnificens, now the world's largest known flying bird. With a wingspan of twenty-five feet, and stretching eleven feet from the tip of its bill to the tip of its tail [...] The giant bird, a new genus and species of teratorn (from the Greek teratos-, meaning wonder, and ornis, meaning bird), was discovered a few years ago by two well-known Argentinian paleontologists, Drs. Eduardo Tonni and Rosendo Pascual. [...] Argentavis magnificens is the oldest known teratorn. It has been dated at between five and eight million years old, or from the late part of the Miocene epoch, on the basis of the fossil mammals found in the same deposits as the fossil bird. Fossils of these same species of mammals have been found at other sites in Argentina for which radiaometric dates are available."[74]
# Dinosaurology
Def. the "branch of paleontology that focuses on studying dinosaurs"[75] is called dinosaurology.
Usually allied with geology rather than biology, paleontology is the study of past life. Dinosaurology is the specific branch of paleontology that is the study of dinosaurs. Because birds are the living descendants of dinosaurs, ornithology might be considered a branch of dinosaurology.
Scientists who study dinosaurs are usually called paleontologists, but might also be called dinosaurologists.
The non-avian dinosaurs lived during the Mesozoic Era, the time period between roughly 252 and 65 million years ago. The first dinosaurs evolved about 225 million years ago, and all but the birds became extinct by the end of the Mesozoic Era.
Dinosaurologists, like other paleontologists need a good grounding in geology and anatomy, as well as whatever other fields their particular study may involve.
# Crocodylomorphology
Def. the study of the Crocodylomorpha is called crocodylomorphology.
# Archelosaurology
Def. the "study of the Archelosauria" is called archelosaurology.
The Archelosauria include the Crurotarsi and Pan-Testudines.
The Crurotarsi include the Archosauria.
The Pan-Testudines include the Testudinata (turtles and tortoises) and †Sauropterygia.
# Cheloniology
Def. the scientific study of turtles is called cheloniology.
Def. the scientific study of tortoises is called testudinology.
# Lepidosaurology
Def. a "taxonomic superorder [within the class Reptilia][76] – the scaled reptiles"[77] is called the Lepidosauria.
Def. a "study of Lepidosauria" is called lepidosaurology.
# Saurology
Def. any "reptile of the order Squamata [that is not a snake][78], usually having four legs, external ear openings, and movable eyelids[79] [and a long slender body and tail][80]" is called a lizard.
Def. a "study of lizards"[81] is called saurology.
# Ophiology
Def. the "study of snakes"[82]is called ophiology.
Ophiology is a specialization of herpetology. Scientists who study ophiology are called herpetologists.
The name of this specialty comes from the Greek word for snake, ophis.
# Herpetology
Def. the "branch of biology dealing with reptiles (Reptilia) and amphibians"[83] is called herpetology.
Scientists who study herpetology are called herpetologists.
Reptiles and amphibians are ectothermic vertebrates that have scales or naked skin. Reptiles lay shelled eggs or give birth to live young. Amphibians lay eggs without shells.
There are more than 10,000 species of reptile.
Reptiles also live in every terrestrial habitat on Earth except the artic and antarctic, but some species also occur in marine environments. Reptiles comprise the taxonomic class Reptilia. The living reptiles include lizards, snakes, tuataras, crocodilians, and turtles.
External Resources:
- [The Reptile Database]
- [Amphibian Species of the World]
# Batrachology
Def. the "study of amphibians"[84] is called batrachology.
Batrachology is a specialty within herpetology. Scientists who study Batrachology are called herpetologists.
The name of this specialty comes from the Ancient Greek word for frog, batrakhos.
There are about 8000 species of living amphibian known to science.
Amphibians live in every terrestrial habitat on Earth except in the arctic and antarctic. Amphibians are also absent from marine environments. The amphibians comprise the taxonomic class Amphibia. The living amphibians include frogs and toads, salamanders and newts, and caecilians.
Def. a "taxonomic [clade][85] within the superclass Tetrapoda – the reptile-like amphibians, which gave rise to the amniotes in the Carboniferous"[86] is called the Reptiliomorpha.
# Ichthyology
Def. "the study of fish"[87] is called ichthyology.
Scientists who study ichthyology are called ichthyologists.
Fishes are endothermic vertebrates that live in the fresh or marine water.
Living species are extremely diverse, and belong to three taxonomic groups, Superclass Agnatha (jawless fishes), Class Chondrichthyes (sharks and rays), and the Osteichthyes (the bony fishes).
There are about 30,000 species of living fish known to science. Fish live in every aquatic habitat on Earth.
About the Photo: Considered a "living fossil" because it is an ancient class of lobe-limbed fish that otherwise went extinct more than 70 million years ago, the first living coelacanth was caught off the east coast of South Africa near the Chalumna River in 1938. Today, at least two major populations of coelacanths are known: one off east Africa, and another near Indonesia. Coelacanths cannot be eaten; their flesh contains an oil that is highly distasteful to human beings. This specimen in the image above weighs 160 pounds (72.6 kg) and measures 5.5 feet (1.67 m) in length.
See also:
Fish
External Resources:
- [FishBase]
- [Icthyology] at the Florida Museum, part of the University of Florida.
# Invertebrate Zoology
Invertebrate zoology is the study of animals that lack a spinal column. This covers approximately 97% of all known living species.
# Echinodermology
Def. study of the echinoderms is called echinodermology.
Echinodermology is a specialty of invertebrate zoology that studies echinoderms. The echinoderms include sea stars, urchins, and crinoids. All species are marine, so this is also a specialty of marine biology. Scientists who study echinoderms most often are called either marine biologists or invertebrate zoologists.
# Malacology
Def. a "soft-bodied invertebrate[88] [of the phylum Mollusca][89], [typically with a hard shell of one or more pieces]"[90] is called a mollusc.
Def. the "study of molluscs"[91] is called malacology.
# Teuthology
Def. "the scientific study of squid (often extended to all cephalopods)"[92] is called teuthology.
# Arthropodology
Def. the "study of arthropods"[93] is called arthropodology.
The Arthropoda include the Chelicerata, Crustacea, Hexapoda, Myriapoda, †Marrellomorpha and the †Trilobitomorpha.
The classes of the Arthropoda include the Arachnida, Branchiopoda, Cephalocarida, Chilopoda, Diplopoda, Entognatha, Insecta, Malacostraca, Maxillopoda, Merostomata, Ostracoda, Pauropoda, Pycnogonida, Remipedia and Symphyla.
# Chelicerata
The Chelicerata contains the classes: Arachnida, Merostomata, Pycnogonida, †Aglaspidida, †Chasmataspidida, and †Eurypterida.
The subphylum Chelicerata constitutes one of the major subdivisions of the phylum Arthropoda that contains the sea spiders, arachnids (including scorpions, spiders, and potentially horseshoe crabs[94]), and several extinct lineages, such as the eurypterids.
# Arachnology
Arachnology is the study of spiders, scorpions, and related arthropods. Scientists who study arachnology are called arachnologists.
Def. the "study of the Arachnida"[95] is called arachnology.
# Arachnida
The Arachnida include the following orders (Ordines): Amblypygi, Araneae, †Haptopoda, Holothyrida, Ixodida, Mesostigmata, Opilioacarida, Opiliones, Palpigradi, †Phalangiotarbida, Pseudoscorpiones, Ricinulei, Sarcoptiformes, Schizomida, Scorpiones, Solifugae, Thelyphonida, †Trigonotarbida, Trombidiformes, †Uraraneida.
# Acarology
Def. the "study of ticks and mites"[96] is called acarology.
"The 6 ordines Holothyrida, Ixodida, Mesostigmata, Opilioacarida, Sarcoptiformes and Trombidiformes are sometimes grouped together as Acari, but there is no consensus on classification above ordinal level, making a Linnean classification difficult."[97]
# Araneology
Def. the "study of the spider, a branch of arachnology"[98] is called araneology.
# Scorpiology
Def. the "scientific study of scorpions"[99] is called scorpiology.
The order (Ordo) is Scorpiones.
# Xiphosurology
Xiphosura is an order of arthropods related to arachnids, or, according to one recent study, actual arachnids,[100] sometimes called horseshoe crabs (a name applied more specifically to the only extant family, Limulidae).
Def. the study of the Merostomata, or Xiphosura, is called Xiphosurology.
# Pantopodology
Def. the study of the Pycnogonida is called pantopodology.
# Carcinology
Def. the "study of crustaceans"[101] is called carcinology.
# Crustacea
The Crustacea contain the classes: Branchiopoda, Cephalocarida, Hexanauplia, Ichthyostraca, Malacostraca, Maxillopoda, Ostracoda and Remipedia.
# Branchiopodology
Def. the study of Branchiopoda is called branchiopodology.
# Brachypodology
The Cephalocarida are a class in the subphylum Crustacea comprising only 12 benthic species discovered in 1955 by Howard L. Sanders,[102] and are commonly referred to as horseshoe shrimps.
Def. the study of the Brachypoda is called brachypodology.
# Malacostracology
Def. the study of the Malacostraca is called Malacostracology.
# Maxillopodology
Def. the study of the Maxillopoda is called maxillopodology.
Maxillopoda is a diverse class of crustaceans including barnacles, copepods and a number of related animals that does not appear to be a monophyletic group, and no single character unites all the members.[103]
# Ostracodology
Def. the study of the Ostracoda is called ostracodology.
# Remipediology
Def. the study of the Remipedia is called remipediology.
# Hexapoda
The Hexapoda consist of the following classes: Entognatha and Insecta.
"Phylogenetic tree of [the] Hexapoda [is shown on the right]. Hexapoda (insects and their six-legged relatives) comprise more than half of all described species and dominate terrestrial and freshwater ecosystems. The tree shown is from a maximum likelihood analysis of 8 genes, calibrated by 89 fossils. Membership of major clades is denoted by coloration of the ring (grey: Entognatha, black: basal insects, cyan: Palaeoptera, magenta: Polyneoptera, green: Paraneoptera, red: Holometabola). Changes in branch coloration denote diversification shifts identified using TurboMEDUSA. Branch colors identify regions of the tree with the same underlying diversification model. Symbols at shifts denote a net upshift (diamond) or down shift (circle). Coloration of symbols reflects the robustness of the shift event across 500-scaled samples taken from the post-burin MCMC chain (black: shift recovered in >80% of samples, grey with black outline: recovery >50%, grey with pale outline: recovery >30%, pale grey: recovery<30%). Black rings are shown at 100 Ma increments from the present."[104]
# Entognathology
Def. the study of the Entognatha is called entognathology.
# Entomology
Entomology is the study of insects (Insecta). Scientists who study entomology are called entomologists.
Def. the "scientific study of insects"[105] is called entomology.
The orders (Ordines) for the Insecta include: Archaeognatha, "Blattodea", Coleoptera, Dermaptera, Diptera, Embiidina, Ephemeroptera, Hemiptera, Hymenoptera, Isoptera, Lepidoptera, Mantodea, "Mecoptera", Megaloptera, Neuroptera, Notoptera, Odonata, Orthoptera, Phasmatodea, Phthiraptera, Plecoptera, "Psocoptera", Raphidioptera, Siphonaptera, Strepsiptera, Thysanoptera, Trichoptera, Zoraptera, and Zygentoma.
# Coleopterology
Def. the "scientific study of beetles"[106] is called coleopterology.
# Lepidopterology
Def. the "scientific study of butterflies and moths"[107] is called lepidopterology.
On the right is an example of Callioratis grandis from Mulanje Mountain, Africa.
Lepidopterology is the study of the Lepidoptera, the group of insects that includes butterflies and moths. It is a specialty of entomology, which is the overall study of insects. Most scientists who study the lepidoptera consider themselves to be entomologists.
# Myrmecology
Def. the "study of ants"[108] is called myrmecology.
# Myriapodology
Def. the "scientific study of myriapods"[109] is called myriapodology.
# Myriapoda
The Myriapoda include the classes: Chilopoda, Diplopoda, Pauropoda, Symphyla, and †Arthropleuridea.
# Chilopodology
Def. the study of the Chilopoda is called chilopodology.
Most centipedes are generally venomous and could inflict a painful bite, injecting their venom through pincer-like appendage known as forcipules, where despite the name, centipedes can have a varying number of legs, ranging from 30 to 354 and centipedes always have an odd number of pairs of legs.[110][111][112] Therefore, no centipede has exactly 100 legs. Similar to spiders and scorpions, centipedes are predominantly carnivorous.[113]
# Diplopodology
Def. the study of the Diplopoda is called diplopodology.
# Pauropodology
Def. the study of the Pauropoda is called pauropodology.
# Symphylology
Def. the study of the Symphyla is called symphylology.
# Arthropleurideology
Def. the study of the †Arthropleuridea is called arthropleurideology.
# †Marrellomorpha
Marrellomorphs are a group of arthropods known from the Cambrian to the Early Devonian.[114]
# †Trilobitomorpha
Trilobites[115][116] meaning "three lobes" are a group of extinct marine arachnomorph arthropods that form the class Trilobita. The trilobites were among the most successful of all early animals, existing in oceans for almost 300 million years.[117]
Trilobites are often placed within the arthropod subphylum Schizoramia within the superclass Arachnomorpha (equivalent to the Arachnata),[118] although several alternative taxonomies are found in the literature.
Trilobites had many lifestyles; some moved over the sea bed as predators, scavengers, or filter feeders, and some swam, feeding on plankton; lifestyles expected of modern marine arthropods are seen in trilobites, with the possible exception of parasitism (where scientific debate continues).[119] Some trilobites (particularly the family Olenidae) are even thought to have evolved a symbiotic relationship with sulfur-eating bacteria from which they derived food.[120]
# Trilobitology
Def. the "study of trilobites"[121] is called trilobitology.
# Annelida
The earliest indisputable fossils of the Annelida appear in the Tertiary period, which began 66 million years ago.[122]
There are over 22,000 living annelid species,[123][124] ranging in size from microscopic to the Australian giant Gippsland earthworm and Amynthas mekongianus (Cognetti, 1922), which can both grow up to 3 meters long.[124][125][126] Although research since 1997 has radically changed scientists' views about the evolutionary family tree of the annelids,[127][128] most textbooks use the traditional classification into the following sub-groups:[125][129]
- Polychaetes (about 12,000 species[123]). As their name suggests, they have multiple chetae ("hairs") per segment. Polychaetes have parapodia that function as limbs, and nuchal organs that are thought to be chemosensors.[125] Most are marine animals, although a few species live in fresh water and even fewer on land.[130]
- Clitellates (about 10,000 species [124]). These have few or no chetae per segment, and no nuchal organs or parapodia. However, they have a unique reproductive organ, the ring-shaped clitellum ("pack saddle") around their bodies, which produces a pupa (cocoon) that stores and nourishes fertilized eggs until they hatch [129][131] or, in moniligastrids, yolky eggs that provide nutrition for the embryos.[124] The clitellates are sub-divided into:[125]
Oligochaetes ("with few hairs"), which includes earthworms. Oligochaetes have a sticky pad in the roof of the mouth.[125] Most are burrowers that feed on wholly or partly decomposed organic materials.[130]
Hirudinea, whose name means "leech-shaped" and whose best known members are leeches.[125] Marine species are mostly blood-sucking parasites, mainly on fish, while most freshwater species are predators.[130] They have suckers at both ends of their bodies, and use these to move rather like inchworms.[132]
- Oligochaetes ("with few hairs"), which includes earthworms. Oligochaetes have a sticky pad in the roof of the mouth.[125] Most are burrowers that feed on wholly or partly decomposed organic materials.[130]
- Hirudinea, whose name means "leech-shaped" and whose best known members are leeches.[125] Marine species are mostly blood-sucking parasites, mainly on fish, while most freshwater species are predators.[130] They have suckers at both ends of their bodies, and use these to move rather like inchworms.[132]
The Archiannelida, minute annelids that live in the spaces between grains of marine sediment, were treated as a separate class because of their simple body structure, but are now regarded as polychaetes.[129] Some other groups of animals have been classified in various ways, but are now widely regarded as annelids:
- Pogonophora / Siboglinidae were first discovered in 1914, and their lack of a recognizable gut made it difficult to classify them. They have been classified as a separate phylum, Pogonophora, or as two phyla, Pogonophora and Vestimentifera. More recently they have been re-classified as a family, Siboglinidae, within the polychaetes.[130][133]
- The Echiura have a checkered taxonomic history: in the 19th century they were assigned to the phylum "Gephyrea", which is now empty as its members have been assigned to other phyla; the Echiura were next regarded as annelids until the 1940s, when they were classified as a phylum in their own right; but a molecular phylogenetics analysis in 1997 concluded that echiurans are annelids.[123][133][134]
- Myzostomida live on crinoids and other echinoderms, mainly as parasites. In the past they have been regarded as close relatives of the trematode flatworms or of the tardigrades, but in 1998 it was suggested that they are a sub-group of polychaetes.[130] However, another analysis in 2002 suggested that myzostomids are more closely related to flatworms or to rotifers and acanthocephales.[133]
- Sipuncula was originally classified as annelids, despite the complete lack of segmentation, bristles and other annelid characters. The phylum Sipuncula was later allied with the Mollusca, mostly on the basis of developmental and larval characters. Phylogenetic analyses based on 79 ribosomal proteins indicated a position of Sipuncula within Annelida.[135] Subsequent analysis of the mitochondrion's DNA has confirmed their close relationship to the Myzostomida and Annelida (including echiurans and Siboglinidae (pogonophorans).[136] It has also been shown that a rudimentary neural segmentation similar to that of annelids occurs in the early larval stage, even if these traits are absent in the adults.[137]
On the right, "This is a parchment worm (Thelepus cincinatus) that is out of its tube. It is also called a Bristleworm and puts out its tentacles to collect its microscopic food."[138]
# Brachiopodology
Def. the study of the Brachiopoda is called brachiopodology.
Lineages of brachiopods that have both fossil and extant taxa appeared in the early Cambrian, Ordovician, and Carboniferous periods, respectively.[139]
The largest brachiopods known – Gigantoproductus and Titanaria, reaching 30 to 38 cm in width – occurred in the upper part of the Lower Carboniferous.[140]
Brachiopod shells can be classified according to the angle between the cardinal plane and the plane where the shells join (commissure); anacline shells have an angle of less than 90°, whereas aspacline shells have a higher angle.[141]
Impunctate shells as solid without any tissue inside them, and pseudopunctate shells are only known from fossil forms.[142][143]
# Bryozoology
Def. a "branch of zoology specializing in Bryozoa"[144] is called bryozoology.
# Chaetognatha
The Chaetognatha fossil range is Lower Cambrian to Recent.[145]
There are more than 120 modern species assigned to over 20 genera.[146] Despite the limited diversity of species, the number of individuals is large.[147]
All chaetognaths are carnivorous, preying on other planktonic animals.[148]
Two chaetognath species, Caecosagitta macrocephala and Eukrohnia fowleri, have bioluminescent organs on their fins.[149][150]
Chaetognaths swim in short bursts using a dorso-ventral undulating body motion, where their tail fin assists with propulsion and the body fins with stabilization and steering.[151] Some species are known to use the neurotoxin tetrodotoxin to subdue prey.[152]
# Cnidariology
Def. the study of the Cnidaria is called cnidariology.
Def. the study of the Myxozoa is called myxozoology.
Myxozoans were originally considered protozoan,[153] and were included among other non-motile forms in the group Sporozoa.[154] As their distinct nature became clear through 18S ribosomal DNA (rDNA) sequencing, they were relocated in the metazoa. Detailed classification within the metazoa was however long hindered by conflicting rDNA evidence: although 18S rDNA suggested an affinity with Cnidaria,[155] other rDNA sampled,[156][157] and the HOX genes of two species,[158] were more similar to those of the Bilateria.
Further testing resolved the genetic conundrum by sourcing the first three previously identified discrepant HOX genes (Myx1-3) to the bryozoan Cristatella mucedo and the fourth (Myx4) to Northern pike, the respective hosts of the two corresponding Myxozoa samples. This explained the confusion: the original experiments had used samples contaminated by tissue from host organisms, leading to false positives for a position among the Bilateria. More careful cloning of 50 coding genes from Buddenbrockia firmly established the clade as severely modified members of the phylum Cnidaria, with medusozoans as their closest relatives. Similarities between myxozoan polar capsules and cnidarian nematocysts had been drawn for a long time, but were generally assumed to be the result of convergent evolution.[159]
Taxonomists now recognize the outdated subgroup Actinosporea as a life-cycle phase of Myxosporea.[160]
# Ctenophorology
Def. the study of the Ctenophora is called ctenophorology.
The Beroida, also known as Nuda, have no feeding appendages, but their large pharynx, just inside the large mouth and filling most of the saclike body, bears "macrocilia" at the oral end which are fused bundles of several thousand large cilia are able to "bite" off pieces of prey that are too large to swallow whole – almost always other ctenophores.[161]
In front of the field of macrocilia, on the mouth "lips" in some species of Beroe, is a pair of narrow strips of adhesive epithelial cells on the stomach wall that "zip" the mouth shut when the animal is not feeding, by forming intercellular connections with the opposite adhesive strip, which streamlines the front of the animal when it is pursuing prey.[162]
# Cycliophorology
Def. the study of the Cycliophora is called cycliophorology.
# Gastrotrichology
Def. the study of the Gastrotricha is called gastrotrichology.
As of 2011, around 790 species have been described.[163] The phylum contains a single class, divided into two orders: the Macrodasyida and the Chaetonotida.[164] The Macrodasyida are wholly marine,[164] but two rare and poorly known species, Marinellina flagellata and Redudasys fornerise, are known from fresh water.[165] The Chaetonotida comprise both marine and freshwater species.[164]
Phylogenetics places the Gastrotricha as close relatives of the flatworms Platyhelminthes, the Ecdysozoa or the Lophotrochozoa.[166]
# Gnathostomulidology
Def. the study of the Gnathostomulida is called gnathostomulidology.
The Gnathostomulida were first recognised and described in 1956.[167]
In many Bursovaginoidea, one of the major group of gnathostomulids, the neck region is slightly narrower than the rest of the body, giving them a distinct head.[168]
Like flatworms they have a ciliated epidermis, but in contrast to flatworms, they have one cilium per cell.[169]
The only sense organs are modified cilia, which are especially common in the head region.[168]
The basal plate is used to scrape smaller organisms off of the grains of sand that make up their anoxic seabed mud habitat.[170]
The mouth opens into a blind-ending tube in which digestion takes place; there is no true anus.[168] However, there is tissue connecting the intestine to the epidermis which may serve as an anal pore.[171]
# Hemichordatology
Def. the study of the Hemichordata is called hemichordatology.
The extinct class Graptolithina is closely related to the pterobranchs.[172]
Acorn worms are solitary worm-shaped organisms that generally live in burrows (the earliest secreted tubes).[173]
While the family Torquaratoridae are free living detritivores, many are well known for their production and accumulation of various halogenated phenols and pyrroles.[174] Pterobranchs are filter-feeders, mostly colonial, living in a collagenous tubular structure called a coenecium.[175]
A post-anal tail is present in juvenile member of the acorn worm family Harrimaniidae.[176]
# Kamptozoology
Def. the study of the Kamptozoa is called kamptozoology.
Entoprocta, coined in 1870,[177] means "anus inside".[178] The alternative name "Kamptozoa", meaning "bent" or "curved" animals, where the prefix "campto-" is explained[179][180] was assigned in 1929.[177] Some authors use Entoprocta[181][182] while others prefer Kamptozoa.[178][183]
Most species are colonial, and their members are known as "zooids",[184] since they are not fully independent animals.[185] Zooids are typically 1 mm long but range from 0.1 to 7 mm long.[178]
# Kinorhynchology
Def. the study of the Kinorhyncha is called kinorhynchology.
Modern species of the Kinorhyncha are 1 mm or less, but Cambrian forms could reach 4 cm.[186]
Unlike some similar invertebrates, they do not have external cilia, but instead have a number of spines along the body, plus up to seven circles of spines around the head.[187]
The head is completely retractable, and is covered by a set of neck plates called placids when retracted.[188] The short hind-gut is lined by cuticle, and empties into an anus at the posterior end of the trunk.[188] The excretory system consists of two protonephridia emptying through pores in the final segment.[188] Some species have simple ocelli on the head, and all species have tiny bristles on the body to provide a sense of touch.[188]
# Loriciferology
Def. the study of the Loricifera is called loriciferology.
Loricifera is a phylum of very small to microscopic marine cycloneuralian sediment-dwelling animals with 37 described species, in nine genera.[189][190][191] Aside from these described species, there are approximately 100 more that have been collected and not yet described.[190] Their sizes range from 100 µm to ca. 1 mm.[192] Their habitat is in the spaces between marine gravel to which they attach themselves. The phylum was discovered in 1983 by Reinhardt Kristensen, in Roscoff, France.[193] They are among the most recently discovered groups of Metazoans.[194] They attach themselves quite firmly to the substrate, and hence remained undiscovered for so long.[191] The first specimen was collected in the 1970s, and later described in 1983.[194] They are found at all depths, in different sediment types, and in all latitudes.[191]
The armor-like lorica consists of a protective external shell or case of encircling plicae.[195] Many of the larvae are acoelomate, with some adults being pseudocoelomate, and some remaining acoelomate.[194]
Fossils have been dated to the late Cambrian.[196]
Morphological studies have traditionally placed the phylum in the Vinctiplicata with the Priapulida; this plus the Kinorhyncha constitutes the taxon Scalidophora, or Cephalorhyncha, where the three phyla share four characters in common — chitinous cuticle, rings of scalids on the introvert, flosculi, and two rings of introvert retracts.[193][194] However, mounting molecular evidence indicates a closer relationship with the Panarthropoda.[197]
# Micrognathozoology
Def. the study of the Micrognathozoa is called micrognathozoology.
Limnognathia maerski is a microscopic platyzoan freshwater animal, discovered living in warm springs on Disko Island, Greenland in 1994, that has variously been assigned as a class or subphylum in the phylum Gnathifera or as a phylum in a Gnathifera superphylum, named Micrognathozoa, related to the rotifers and gnathostomulids, grouped together as the Gnathifera.[198][199]
# Nematodology
Def. the study of the Nematoda is called nematodology.
The nematodes or roundworms constitute the phylum Nematoda, also called Nemathelminthes.[200][201]
A 2013 survey of animal biodiversity published in the mega journal Zootaxa puts the number of species at over 25,000.[202][203]
Nematods are found in every part of the earth's lithosphere,[204] even at great depths, 0.9–3.6 km below the surface of the Earth in gold mines in South Africa.[205][206][207][208][209] They represent 90% of all animals on the ocean floor.[210] In total, 4.4 × 1020 nematodes inhabit the Earth's topsoil, or approximately 60 billion for each human, with the highest densities observed in tundra and boreal forests.[211] Their numerical dominance, often exceeding a million individuals per square meter and accounting for about 80% of all individual animals on earth, their diversity of lifecycles, and their presence at various trophic levels point to an important role in many ecosystems.[211][212] They have been shown to play crucial roles in polar ecosystem.[213][214] The roughly 2,271 genera are placed in 256 families.[215] The many parasitic forms include pathogens in most plants and animals. A third of the genera occur as parasites of vertebrates; about 35 nematode species occur in humans.[215]
"In short, if all the matter in the universe except the nematodes were swept away, our world would still be dimly recognizable, and if, as disembodied spirits, we could then investigate it, we should find its mountains, hills, vales, rivers, lakes, and oceans represented by a film of nematodes. The location of towns would be decipherable, since for every massing of human beings, there would be a corresponding massing of certain nematodes. Trees would still stand in ghostly rows representing our streets and highways. The location of the various plants and animals would still be decipherable, and, had we sufficient knowledge, in many cases even their species could be determined by an examination of their erstwhile nematode parasites."[216]
# Nematomorphology
Def. the study of the Nematomorpha is called nematomorphology.
The adult worms are free-living, but the larvae are parasitic on arthropods, such as beetles, cockroaches, mantids, orthopterans, and crustaceans.[217] About 351 freshwater species are known[163] and a conservative estimate suggests that there may be about 2000 freshwater species worldwide.[218] The name "Gordian" stems from the legendary Gordian knot. This relates to the fact that nematomorpha often tie themselves in knots.[219]
The nervous system consists of a nerve ring near the anterior end of the animal, and a ventral nerve cord running along the body.[220]
# Nemerteology
Def. the study of the Nemertea is called nemerteology.
Nemertea is a phylum of invertebrate animals also known as ribbon worms or proboscis worms.[221] Alternative names for the phylum have included Nemertini, Nemertinea and Rhynchocoela.[222]
In 1995, a total of 1,149 species had been described and grouped into 250 genera.[223]
Nemertea are named after the Greek sea-nymph Nemertes, one of the daughters of Nereus and Doris.[224] Alternative names for the phylum have included Nemertini, Nemertinea, and Rhynchocoela.[222] The Nemertodermatida are a separate phylum, whose closest relatives appear to be the Acoela.[225][226]
# Onychophorology
Def. the study of the Onychophora is called onychophorology.
Onychophora, commonly known as velvet worms (due to their velvety texture and somewhat wormlike appearance) or more ambiguously as peripatus (after the first described genus, Peripatus), is a phylum of elongate, soft-bodied, many-legged panarthropods.[227][228] In appearance they have variously been compared to worms with legs, caterpillars, and slugs.[229]
"Because they resemble worms with legs ... Superficially they resemble caterpillars, but have also been compared with slugs."[229]
It is the only phylum within Animalia that is wholly endemic to terrestrial environments.[230] Velvet worms are considered close relatives of the Arthropoda and Tardigrada, with which they form the taxon Panarthropoda.[231]
# Phoronidology
Def. the study of the Phoronida is called phoronidology.
Phoronis is the name of one of the two genera of Phoronids.[232]
As of 2010 there are no indisputable body fossils of phoronids.[233]
Phoronids may be members of the protostome super-phylum Lophotrochozoa.[234]
Phoronids and brachiopods may be sister-groups, while others place phoronids as a sub-group within brachiopoda.[235]
The diagram on the right describes the anatomy of an adult phoronid.[232][236][237]
Most adult phoronids are 2 to 20 cm long and about 1.5 mm wide,
[236] although the largest are 50 cm long.[237] Their skins have no cuticle but secrete rigid tubes of chitin,[236] similar to the material used in arthropods' exoskeletons,[238] and sometimes reinforced with sediment particles and other debris.[232] Most species' tubes are erect, but those of Phoronis vancouverensis are horizontal and tangled.[239] Phoronids can move within their tubes but never leave them.[236] The bottom end of the body is an ampulla (a flask-like swelling in a tube-like structure[240]),[236] which anchors the animal in the tube and enables it to retract its body when threatened,[237] reducing the body to 20 percent of its maximum length.[232] Longitudinal muscles retract the body very quickly, while circular muscles slowly extend the body by compressing the internal fluid.[237]
For feeding and respiration each phoronid has at the top end a lophophore, a "crown" of tentacles with which the animal filter-feeds. In small species the "crown" is a simple circle, in medium-size species it is bent into the shape of a horseshoe with tentacles on the outer and inner sides, and in the largest species the ends of the horseshoe wind into complex spirals. These more elaborate shapes increase the area available for feeding and respiration.[236] The tentacles are hollow, held upright by fluid pressure, and can be moved individually by muscles.[237]
The mouth is inside the base of the crown of tentacles but to one side. The gut runs from the mouth to one side of the stomach, in the bottom of the ampulla. The intestine runs from the stomach, up the other side the body, and exits at the anus, outside and a little below the crown of tentacles. The gut and intestine are both supported by two mesenteries (partitions that run the length of the body) connected to the body wall, and another mesentery connects the gut to the intestine.[236]
The body is divided into coeloms,[236] compartments lined with mesothelium.[241] The main body cavity, under the crown of tentacles, is called the metacoelom, and the tentacles and their base share the mesocoelom.[236] Above the mouth is the epistome, a hollow lid which can close the mouth.[237] The cavity in the epistome is sometimes called the protocoelom, although other authors disagree that it is a coelom[242] and Ruppert, Fox and Barnes think it is built by a different process.[236]
# Placozoology
Def. the study of the Placozoa is called placozoology.
The Placozoa are a basal form of free-living (non-parasitic) multicellular organism.[243] They are the simplest in structure of all animals. Three genera have been found: the classical Trichoplax adhaerens, Hoilungia hongkongensis, and Polyplacotoma mediterranea, where the last appears most basal. The last two have been found only since 2017.[244][245][246][247][248] Although the Placozoa were first discovered in 1883[249][250] and since the 1970s more systematically analyzed,[251] a common name does not yet exist for the taxon; the scientific name means "flat animals".[252]
# Platyhelminthology
Def. the study of the Platyhelminthes is called platyhelminthology.
Like other bilaterians, they have three main cell layers (endoderm, mesoderm, and ectoderm),[253] while the radially symmetrical cnidarians and ctenophores (comb jellies) have only two cell layers.[254] Beyond that, they are "defined more by what they do not have than by any particular series of specializations."[255] Unlike other bilaterians, Platyhelminthes have no internal body cavity, so are described as acoelomates. They also lack specialized circulatory and respiratory organs, both of these facts are defining features when classifying a flatworm's anatomy.[253][256] Their bodies are soft and unsegmented.[257]
# Poriferology
Def. the study of the Porifera is called poriferology.
Def. a "branch of zoology concerning sponges or Porifera"[258] is called spongiology.
# Rhombozoology
Def. the study of the Rhombozoa is called rhombozoology.
Classification is controversial.[259] Traditionally, dicyemids have been grouped with the Orthonectida in the Mesozoa, and, as of 2017, molecular evidence[260] appears to confirm this.
However, other molecular phylogenies have placed the dicyemids more closely related to the Nematoda (roundworms).[261] Additional molecular evidence suggests that this phylum is derived from the Lophotrochozoa.[262][263]
The phylum is not divided in classes or orders, but contains three families, Conocyemidae, Dicyemidae, and Kantharellidae.[264]
# Rotiferology
Def. the study of the Rotifera is called rotiferology.
Def. any "of many minute aquatic multicellular organisms, of the phylum Rotifera, that have a ring of cilia resembling a wheel"[265] is called a rotifer.
# Scalidophorology
Def. the study of the Scalidophora is called scalidophorology.
Scalidophora is a group of marine pseudocoelomate protostomes that was proposed on morphological grounds to unite three phyla: the Kinorhyncha, the Priapulida and the Loricifera.[266][267] The three phyla have four characters in common — chitinous cuticle that is moulted, rings of scalids on the introvert, flosculi, and two rings of introvert retracts.[268] However, the monophyly of the Scalidophora is not supported by molecular studies, where the position of the Loricifera was uncertain[266] or as sister to the Panarthropoda.[267]
The group has also been considered a single group, Cephalorhyncha,[269] with three classes.
The group is named after the spines (scalids) covering the introvert (head that can be retracted into the trunk).[270]
# Sipunculology
Def. the study of the Sipuncula is called sipunculology.
The worm Sipunculus nudus was first described in 1767.[271] In 1814, the word "Sipuncula" was used to describe the family (now Sipunculidae),[272] and in time, the term came to be used for the whole phylum.[273] This is a relatively understudied group, and it is estimated there may be around 162 species worldwide.[274]
The phylogenetic placement of this phylum in the past has proved troublesome. Originally classified as annelids, despite the complete lack of segmentation, bristles and other annelid characters, the phylum Sipuncula was later allied with the Mollusca, mostly on the basis of developmental and larval characters. Currently these two phyla have been included in a larger group, the Lophotrochozoa, that also includes the annelids, the nemertea (ribbon worms) and several other phyla. Phylogenetic analyses based on 79 ribosomal proteins indicated a position of Sipuncula within Annelida.[275][135] Subsequent analysis of the mitochondrion's DNA has confirmed their close relationship to the Myzostomida and Annelida (including echiurans and Siboglinidae (pogonophorans)).[136] It has also been shown that a rudimentary neural segmentation similar to that of annelids occurs in the early larval stage, even if these traits are absent in the adults.[276]
# Tardigradology
Def. the study of the Tardigrada is called tardigradology.
Tardigrades, known colloquially as water bears or moss piglets,[277][278][279][280] are a phylum of water-dwelling eight-legged segmented micro-animals.[277][281] They were first described by the German zoologist Johann August Ephraim Goeze in 1773, who called them little water bears. In 1777, the Italian biologist Lazzaro Spallanzani named them Tardigrada, which means "slow steppers".[282]
They have been found everywhere, from mountaintops to the deep sea and mud volcanoes,[283] and from tropical rain forests to the Antarctic.[284] Tardigrades are among the most resilient animals known,[285][286] with individual species able to survive extreme conditions—such as exposure to extreme temperatures, extreme pressures (both high and low), air deprivation, radiation, dehydration, and starvation—that would quickly kill most other known forms of life. Tardigrades have survived exposure to outer space.[287][288] About 1,150 known species[163][289] form the phylum Tardigrada, a part of the superphylum Ecdysozoa. The group includes fossils dating from 530 million years ago, in the Cambrian period.[290]
Tardigrades are usually about 0.5 mm long when fully grown.[277] They are short and plump, with four pairs of legs, each ending in claws (usually four to eight) or sucking disks.[277][291] Tardigrades are prevalent in mosses and lichens and feed on plant cells, algae, and small invertebrates. When collected, they may be viewed under a very low-power microscope, making them accessible to students and amateur scientists.[292]
# Xenacoelomorphology
Def. the study of the Xenacoelomorpha is called xenacoelomorphology.
Xenacoelomorpha[293] is a basal bilaterian phylum of small and very simple animals, grouping the xenoturbellids with the acoelomorphs. This grouping was suggested by morphological synapomorphies,[294] and confirmed by phylogenomic analyses of molecular data.[295][293]
The clade Xenacoelomorpha, grouping Acoelomorpha and the genus Xenoturbella, was revealed by molecular studies.[295] Initially it was considered to be a member of the deuterostomes[293], but a more recent transcriptome analysis concluded that it is the sister group to the Nephrozoa, which includes the protostomes and the deuterostomes, being therefore the basalmost bilaterian clade.[296][297]
# Systematics & Taxonomy
Superregnum: Eukaryota[298]
Systematics is the study of the evolutionary relationships among organisms. It includes taxonomy, which is the study of the names of organisms and their organization into categories. Scientists who study systematics are called systematists, while taxonomists primarily study taxonomy. Most systematists are also taxonomists.
Living organisms are grouped into a hierarchy of categories. The main categories are Kingdom (or Regnum, pl. Regna), Phylum (pl. Phyla), Class, Order, Family, Genus (pl. Genera), and Species (pl. Species). Every living organism is classified into one, and only one, of each of those categories. There are additional categories used for some groups, but not all.
The classification of organisms can change as more is learned about the living world around us.
Below are two ideas of how life may be divided into Kingdoms (Regna).
- Four Regna listed by Whittaker & Margulis (1978): Animalia - Plantae - Fungi - Protista
- Five Regna listed Cavalier-Smith (1981): Animalia - Plantae - Fungi - Chromista - Protozoa
Below is one recent list of the Phyla of within the Kingdom Animalia. Note number 8, Chordata. That is the Phylum that includes vertebrates, the animals with a spinal column that includes humans.
Regnum: Animalia
Phyla (36):
- Acanthocephala
- Annelida
- Arthropoda
- Brachiopoda
- Bryozoa
- Cephalorhyncha
- Chaetognatha
- Chordata
- Cnidaria
- Ctenophora
- Cycliophora
- Echinodermata
- Echiura
- Gastrotricha
- Gnathostomulida
- Hemichordata
- Kamptozoa
- Kinorhyncha
- Loricifera
- Micrognathozoa
- Mollusca
- Nematoda
- Nematomorpha
- Nemertea
- Onychophora
- Orthonectida
- Phoronida
- Placozoa
- Platyhelminthes
- Porifera
- Rhombozoa
- Rotifera
- Sipuncula
- Tardigrada
- Xenacoelomorpha
# Parasitology
"Humans are hosts to nearly 300 species of parasitic worms and over 70 species of protozoa, some derived from our primate ancestors and some acquired from the animals we have domesticated or come in contact with during our relatively short history on Earth".[299]
______________
Parasitology is the study of parasites. In this context, a parasite is usually an invertebrate, and as such parasitology is a specialization of invertebrate zoology. Scientists that study parasites are called parasitologists.
Parasites are organisms that live on or in, and take their nutrition from, another living organism called a host. Rarely do parasites kill their hosts, since finding a new host can be quite difficult. Individual parasites may do little harm to their host, but large numbers of them can cause great problems. This kind of relationship where one organism lives off another giving either nothing in return or causing harm is called parasitism.
Parasites may be found in many invertebrate taxonomic groups. Commonly encountered parasites include tapeworms, roundworms, and lice.
# Helminthology
Def. the "branch of zoology related to the study of helminths (parasitic worms)" is called helminthology.
# Acanthocephalology
Def. the study of the Acanthocephala is called acanthocephalology.
The "Acanthocephala are descended from, and should be considered as, highly modified rotifers. Genetic research has determined this is unequivocal; the Acanthocephalans are modified rotifers".[300]
Acanthocephalans have complex life cycles, involving at least two hosts, which may include invertebrates, fish, amphibians, birds, and mammals.[301][302][303] About 1420 species have been described.[304][305]
# Orthonectidology
Def. the study of the Orthonectida is called orthonectidology.
Orthonectida is a small phylum of poorly known parasites of marine invertebrates.[306]
The adults are microscopic wormlike animals, consisting of a single layer of ciliated outer cells surrounding a mass of sex cells, that swim freely within the bodies of their hosts, which include flatworms, polychaete worms, bivalve molluscs, and echinoderms, and are gonochoristic, with separate male and female individuals.[307]
When they are ready to reproduce, the adults leave the host, and sperm from the males penetrate the bodies of the females to achieve internal fertilisation, where the resulting zygote develops into a ciliated larva that escapes from the mother to seek out new hosts so as to lose its cilia and develop into a syncytial plasmodium larva, which, in turn, breaks up into numerous individual cells that become the next generation of adults.[307][308]
# Hypotheses
An hypothesis is a scientific statement made to explain some part of the world. It is not a guess. It is testable by scientific means, and is falsifiable (able to be disproved) by those means. Coming up with hypotheses and testing them are the main occupation of science.
- The genetic classification of animals may not match the current classification before genetic evidence.
# Acknowledgements
The content on this page was first contributed by: Henry A. Hoff.
Initial content for this page in some instances came from Wikiversity. | https://www.wikidoc.org/index.php/Zoology | |
1d82e17080ce8085aae3330f5521edfd893dd3c6 | wikidoc | Zymurgy | Zymurgy
Zymurgy or zymology is the study of fermentation. The word was originally used to describe the science involved in these processes but it has since become more broadly used to describe the brewing of alcoholic beverages. A zymurgist (or zymologist) is one who studies zymurgy.
Zymurgy is the name of a homebrewers magazine. The word also can be found in the names of several organizations involved in brewing alcohol.
# History
Louis Pasteur is considered to have been the first zymologist when, in 1857, he connected yeast to fermentation. Pasteur originally defined fermentation as "respiration without air". The German Eduard Buchner, winner of the 1907 Nobel Prize in chemistry, later determined that fermentation was actually caused by the yeast's secretion of an enzyme that he called zymase.
# Trivia
Zymurgy is the last word in most English-language dictionaries, excluding proper nouns and onomatopoetic words. | Zymurgy
Zymurgy or zymology is the study of fermentation. The word was originally used to describe the science involved in these processes but it has since become more broadly used to describe the brewing of alcoholic beverages. A zymurgist (or zymologist) is one who studies zymurgy.
Zymurgy is the name of a homebrewers magazine. The word also can be found in the names of several organizations involved in brewing alcohol.
# History
Louis Pasteur is considered to have been the first zymologist when, in 1857, he connected yeast to fermentation. Pasteur originally defined fermentation as "respiration without air". The German Eduard Buchner, winner of the 1907 Nobel Prize in chemistry, later determined that fermentation was actually caused by the yeast's secretion of an enzyme that he called zymase.[1]
# Trivia
Zymurgy is the last word in most English-language dictionaries, excluding proper nouns and onomatopoetic words. | https://www.wikidoc.org/index.php/Zymology | |
06023da732f3bcdd5c8b5a33db2ffb588199b893 | wikidoc | 1 E7 s | 1 E7 s
To help compare orders of magnitude of different times this page lists times between 116 days and 1157 days or 3.2 years (107 seconds and 108 seconds).
- Shorter times
- 10 megaseconds = 115.74 days
- 128.6 days — half life of thulium-170
- 138 days — half life of polonium- 210
- 224.701 days — one orbit of Venus
- 271.79 days — half life of cobalt-57
- 280 days — average length of a human pregnancy; ~24 million seconds
- 330 days — half life of vanadium-49
- 333.5 days — half life of californium-248
- 353, 354 or 355 days — the lengths of regular years in some lunisolar calendars
- 354.37 days — 12 lunar months; the average length of a year in lunar calendars
- \pi \cdot 10^7 s — The value of pi times 107 seconds is sometimes given as an approximate year value; it works out to 363.61026 days.
- 365 days — a regular year in many solar calendars; ~31.53 million seconds
- 365.24219 days — a mean tropical year near the year 2000
- 365.2424 days — a vernal equinox year.
- 365.2425 days — the average length of a year in the Gregorian calendar
- 365.25 days — the average length of a year in the Julian calendar
- 365.2564 days — a sidereal year
- 366 days — a leap year in many solar calendars; 31.62 million seconds
- 373.59 days — half-life of ruthenium-106
- 383, 384 or 385 days — the lengths of leap years in some lunisolar calendars
- 383.9 days — 13 lunar months; leap year in some lunisolar calendars
- 396.1 days — half-life of neptunium-235
- 462.6 days — half-life of cadmium-109
- 1.88 years — one orbit of Mars
- 1.92 years — half life of thulium-171
- 100 megaseconds = 3.2 years
- Longer times | 1 E7 s
Template:Associations/Orders of magnitude (time)
To help compare orders of magnitude of different times this page lists times between 116 days and 1157 days or 3.2 years (107 seconds and 108 seconds).
- Shorter times
- 10 megaseconds = 115.74 days
- 128.6 days — half life of thulium-170
- 138 days — half life of polonium- 210
- 224.701 days — one orbit of Venus
- 271.79 days — half life of cobalt-57
- 280 days — average length of a human pregnancy; ~24 million seconds
- 330 days — half life of vanadium-49
- 333.5 days — half life of californium-248
- 353, 354 or 355 days — the lengths of regular years in some lunisolar calendars
- 354.37 days — 12 lunar months; the average length of a year in lunar calendars
- <math>\pi \cdot 10^7 s</math> — The value of pi times 107 seconds is sometimes given as an approximate year value; it works out to 363.61026 days.
- 365 days — a regular year in many solar calendars; ~31.53 million seconds
- 365.24219 days — a mean tropical year near the year 2000
- 365.2424 days — a vernal equinox year.
- 365.2425 days — the average length of a year in the Gregorian calendar
- 365.25 days — the average length of a year in the Julian calendar
- 365.2564 days — a sidereal year
- 366 days — a leap year in many solar calendars; 31.62 million seconds
- 373.59 days — half-life of ruthenium-106
- 383, 384 or 385 days — the lengths of leap years in some lunisolar calendars
- 383.9 days — 13 lunar months; leap year in some lunisolar calendars
- 396.1 days — half-life of neptunium-235
- 462.6 days — half-life of cadmium-109
- 1.88 years — one orbit of Mars
- 1.92 years — half life of thulium-171
- 100 megaseconds = 3.2 years
- Longer times | https://www.wikidoc.org/index.php/1_E7_s | |
22ee0adbe6b96febd9c021932e7ddf32bb5098d5 | wikidoc | 2C-T-7 | 2C-T-7
2C-T-7 is a hallucinogenic phenethylamine of the 2C family. In his book PIHKAL (Phenethylamines I Have Known and Loved), Shulgin lists the dosage range as 10 to 30 mg. 2C-T-7 is generally taken orally, and produces psychedelic and entheogenic effects that last 8 to 15 hours. Up until a crackdown on sales after multiple reported deaths, 2C-T-7 was sold commercially in Dutch smartshops and online as "Blue Mystic". Other names that were sometimes used include Nexus, Lucky 7, 7 up, 7th heaven, Beautiful, and Tripstasy.
There has been little real research done on this chemical other than Shulgin's comments in PiHKAL. There have been a few small animal studies mostly aimed at detecting metabolites, and an informal amateur research paper written by Murple called "Sulfurous Samadhi."
# Pharmacology
The mechanism that produces the hallucinogenic and entheogenic effects of 2C-T-7 is most likely to result from action as a 5-HT2A serotonin receptor agonist in the brain, a mechanism of action shared by all of the hallucinogenic tryptamines and phenethylamines.
2C-T-7 also has a separate action as a selective monoamine oxidase A inhibitor. This makes 2C-T-7 a potentially dangerous drug as at high doses it can slow down the degradation of serotonin in the brain, which can lead to serotonin syndrome and potential death without treatment.
Several of the deaths involving 2C-T-7 followed co-administration of the drug with stimulants such as MDMA and ephedrine, so these kind of combinations should be avoided.
# Effects
2C-T-7 is hallucinogenic. In PiHKAL, Shulgin writes that the hallucinations are unique. He also comments on the tenseness of his muscles and his change in voice tone, which lasted some days. Erowid gives the following effects list:
### Positive
- sense of well-being (enhanced lucidity, sense of inner peace)
- emotional opening
- significant closed and open eye visuals
- increased appreciation of music
### Neutral
- general change in consciousness (as with most psychoactives)
- pupil dilation
- change in perception of time
- visual hallucinations
- aural hallucinations
### Negative
- nausea and vomiting
- muscle tension
- irritating body load
- muscle tremors and/or convulsions
- memory loss (at higher doses)
- delirium (at higher doses) (potentially dangerous)
- violent behaviour (at higher doses)
- death
The drug can be taken orally or snorted, although nasal administration is extremely painful. Use of 2C-T-7 as a nootropic at low doses of 1-10mg has been reported, and it may be useful for this purpose in a similar manner to LSD, which shows modest stimulant and nootropic effects at doses of 10 µg.
# Deaths
The Partnership for a Drug-Free America reports that 2C-T-7 can be lethal even in small doses, although this may be misleading as small is a relative term. However, there have been at least three reported deaths related to 2C-T-7 use, mainly at very high doses of 30mg or more or combined with stimulants such as MDMA, as well as a number of very bad trips and hospitalizations , these mostly followed insufflation of 2C-T-7. In January of 2002, Rolling Stone published an article about 2C-T-7 entitled "The New (legal) Killer Drug", although the legal status of the drug was misrepresented in the article. It can cause nausea and, as with many other drugs, may be dangerous when combined with alcohol and/or stimulants.
# Legality
Around the year 2000, 2C-T-7 began to change from an obscure chemical to a drug used at parties and clubs in North America and Europe as it became available through a number of grey-market commercial vendors. This aroused the attention of the authorities, and since many countries have scheduled the chemical.
### Australia
In Australia, 2C-T-2 and 2C-T-7 are covered by the country's comparatively strict analogue drug laws.
### Canada
2C-T-7 could be argued to be analogues of either 2C-B or mescaline.
### Sweden
2C-T-2 became commercially available in Sweden in the summer of 1998, being sold in smartshops similar to those in the Netherlands. On April 1, 1999, both 2C-T-2 and 2C-T-7, along with MBDB, BDB, 2C-B and PMMA, were banned in Sweden. This was not done by appending these drugs to the country's normal drug laws, but by passing a new law, "Förordning (1999:58) om förbud mot vissa hälsofarliga varor," which banned the drugs as being materials dangerous to health.
### UK
In 1999, Alexander Shulgin was sent a copy of a letter from the British Home Office to several of its administrative associates which in effect placed all compounds listed in PiHKAL into Class A, Britain's equivalent of Schedule I.
### US
On September 20, 2002, 2C-T-7 was classified as a Schedule I substance in the United States by an emergency ruling by the DEA. On March 18, 2004, the DEA published a Final Rule in the Federal Register permanently placing 2C-T-7 in Schedule I. (69 FR 12794).
# Notes
- ↑ Alexander Shulgin. "PIHKAL #43"..mw-parser-output cite.citation{font-style:inherit}.mw-parser-output q{quotes:"\"""\"""'""'"}.mw-parser-output code.cs1-code{color:inherit;background:inherit;border:inherit;padding:inherit}.mw-parser-output .cs1-lock-free a{background:url("")no-repeat;background-position:right .1em center}.mw-parser-output .cs1-lock-limited a,.mw-parser-output .cs1-lock-registration a{background:url("")no-repeat;background-position:right .1em center}.mw-parser-output .cs1-lock-subscription a{background:url("")no-repeat;background-position:right .1em center}.mw-parser-output .cs1-subscription,.mw-parser-output .cs1-registration{color:#555}.mw-parser-output .cs1-subscription span,.mw-parser-output .cs1-registration span{border-bottom:1px dotted;cursor:help}.mw-parser-output .cs1-hidden-error{display:none;font-size:100%}.mw-parser-output .cs1-visible-error{display:none;font-size:100%}.mw-parser-output .cs1-subscription,.mw-parser-output .cs1-registration,.mw-parser-output .cs1-format{font-size:95%}.mw-parser-output .cs1-kern-left,.mw-parser-output .cs1-kern-wl-left{padding-left:0.2em}.mw-parser-output .cs1-kern-right,.mw-parser-output .cs1-kern-wl-right{padding-right:0.2em}
- ↑ "Sulfurous Samadhi". 02-06-2001. Check date values in: |date= (help)
- ↑ Fantegrossi, WE (2005). "Hallucinogen-like actions of 2,5-dimethoxy-4-(n)-propylthiophenethylamine (2C-T-7) in mice and rats". Psychopharmacology (Berlin). 181 (3): 496–503. Unknown parameter |coauthors= ignored (help); Unknown parameter |month= ignored (help)
- ↑ Gallardo-Godoy, A (April 7, 2005). "Sulfur-substituted alpha-alkyl phenethylamines as selective and reversible MAO-A inhibitors: biological activities, CoMFA analysis, and active site modeling". Journal of Medicinal Chemistry. 48 (7): 2407–19. Unknown parameter |coauthors= ignored (help); Check date values in: |date= (help)
- ↑ Erowid. "2C-T-7 Vault: Effects".
- ↑ East Bay Express (01-02-07). "2C-T-7's Bad Trip". Check date values in: |date= (help)
- ↑ The respondent was a 43 year old male who said that he had "ingested almost 2 grams of 2CT7 over a 7 month period," taking "a daily +1 museum dosage of 5-10mg." No tolerance was noticed. He said "I found it to be one of the most powerful cognition enhancers I've ever encountered," but mentioned that "it was difficult to stop taking 2CT7 and I used a SSRI to regain serotonin balance." Discussing the long term effects this has had on him, he says "the introspective and emotionally beneficial aspects of 2CT7 have allowed me to develop and appreciate my relationships with people. 2CT7 has also helped to remove personal obstacles that have prohibited progress in my life.", 2C-T-2 & 2C-T-7 User Surveys by Murple, Feb 6, 2001
- ↑ Partnership for a Drug-Free America. "2C-B, 2C-T-7". Retrieved 2006-10-04.
- ↑ Erowid. "Third Confirmed 2C-T-7 Death". Retrieved 2006-12-06. Unknown parameter |authorlin= ignored (help)
- ↑ Erowid. "2C-T-7 Reports Train Wrecks & Disasters". Retrieved 2006-12-06.
- ↑ DEA. "Micgrogram Bulletin Jan 2004".
- ↑ US Department of Justice. "2C-T-7 Fast Facts" (PDF). | 2C-T-7
2C-T-7 is a hallucinogenic phenethylamine of the 2C family. In his book PIHKAL (Phenethylamines I Have Known and Loved), Shulgin lists the dosage range as 10 to 30 mg. 2C-T-7 is generally taken orally, and produces psychedelic and entheogenic effects that last 8 to 15 hours.[1] Up until a crackdown on sales after multiple reported deaths, 2C-T-7 was sold commercially in Dutch smartshops and online as "Blue Mystic". Other names that were sometimes used include Nexus, Lucky 7, 7 up, 7th heaven, Beautiful, and Tripstasy.
There has been little real research done on this chemical other than Shulgin's comments in PiHKAL. There have been a few small animal studies mostly aimed at detecting metabolites, and an informal amateur research paper written by Murple called "Sulfurous Samadhi."[2]
# Pharmacology
The mechanism that produces the hallucinogenic and entheogenic effects of 2C-T-7 is most likely to result from action as a 5-HT2A serotonin receptor agonist in the brain, a mechanism of action shared by all of the hallucinogenic tryptamines and phenethylamines.[3]
2C-T-7 also has a separate action as a selective monoamine oxidase A inhibitor. This makes 2C-T-7 a potentially dangerous drug as at high doses it can slow down the degradation of serotonin in the brain, which can lead to serotonin syndrome and potential death without treatment.[4]
Several of the deaths involving 2C-T-7 followed co-administration of the drug with stimulants such as MDMA and ephedrine, so these kind of combinations should be avoided.
# Effects
2C-T-7 is hallucinogenic. In PiHKAL, Shulgin writes that the hallucinations are unique. He also comments on the tenseness of his muscles and his change in voice tone, which lasted some days. Erowid gives the following effects list:[5]
### Positive
- sense of well-being (enhanced lucidity, sense of inner peace)
- emotional opening
- significant closed and open eye visuals
- increased appreciation of music
### Neutral
- general change in consciousness (as with most psychoactives)
- pupil dilation
- change in perception of time
- visual hallucinations
- aural hallucinations
### Negative
- nausea and vomiting
- muscle tension
- irritating body load
- muscle tremors and/or convulsions
- memory loss (at higher doses)
- delirium (at higher doses) (potentially dangerous)
- violent behaviour (at higher doses)
- death
The drug can be taken orally or snorted, although nasal administration is extremely painful.[6] Use of 2C-T-7 as a nootropic at low doses of 1-10mg has been reported, and it may be useful for this purpose in a similar manner to LSD, which shows modest stimulant and nootropic effects at doses of 10 µg.[7]
# Deaths
The Partnership for a Drug-Free America reports that 2C-T-7 can be lethal even in small doses,[8] although this may be misleading as small is a relative term. However, there have been at least three reported deaths related to 2C-T-7 use, mainly at very high doses of 30mg or more or combined with stimulants such as MDMA[9], as well as a number of very bad trips and hospitalizations [10], these mostly followed insufflation of 2C-T-7. In January of 2002, Rolling Stone published an article about 2C-T-7 entitled "The New (legal) Killer Drug", although the legal status of the drug was misrepresented in the article. It can cause nausea and, as with many other drugs, may be dangerous when combined with alcohol and/or stimulants.
# Legality
Around the year 2000, 2C-T-7 began to change from an obscure chemical to a drug used at parties and clubs in North America and Europe as it became available through a number of grey-market commercial vendors. This aroused the attention of the authorities, and since many countries have scheduled the chemical.
### Australia
In Australia, 2C-T-2 and 2C-T-7 are covered by the country's comparatively strict analogue drug laws.
### Canada
2C-T-7 could be argued to be analogues of either 2C-B or mescaline.
### Sweden
2C-T-2 became commercially available in Sweden in the summer of 1998, being sold in smartshops similar to those in the Netherlands. On April 1, 1999, both 2C-T-2 and 2C-T-7, along with MBDB, BDB, 2C-B and PMMA, were banned in Sweden. This was not done by appending these drugs to the country's normal drug laws, but by passing a new law, "Förordning (1999:58) om förbud mot vissa hälsofarliga varor," which banned the drugs as being materials dangerous to health.
### UK
In 1999, Alexander Shulgin was sent a copy of a letter from the British Home Office to several of its administrative associates which in effect placed all compounds listed in PiHKAL into Class A, Britain's equivalent of Schedule I.
### US
On September 20, 2002, 2C-T-7 was classified as a Schedule I substance in the United States by an emergency ruling by the DEA. On March 18, 2004, the DEA published a Final Rule in the Federal Register permanently placing 2C-T-7 in Schedule I. (69 FR 12794).[11][12]
# Notes
- ↑ Alexander Shulgin. "PIHKAL #43"..mw-parser-output cite.citation{font-style:inherit}.mw-parser-output q{quotes:"\"""\"""'""'"}.mw-parser-output code.cs1-code{color:inherit;background:inherit;border:inherit;padding:inherit}.mw-parser-output .cs1-lock-free a{background:url("https://upload.wikimedia.org/wikipedia/commons/thumb/6/65/Lock-green.svg/9px-Lock-green.svg.png")no-repeat;background-position:right .1em center}.mw-parser-output .cs1-lock-limited a,.mw-parser-output .cs1-lock-registration a{background:url("https://upload.wikimedia.org/wikipedia/commons/thumb/d/d6/Lock-gray-alt-2.svg/9px-Lock-gray-alt-2.svg.png")no-repeat;background-position:right .1em center}.mw-parser-output .cs1-lock-subscription a{background:url("https://upload.wikimedia.org/wikipedia/commons/thumb/a/aa/Lock-red-alt-2.svg/9px-Lock-red-alt-2.svg.png")no-repeat;background-position:right .1em center}.mw-parser-output .cs1-subscription,.mw-parser-output .cs1-registration{color:#555}.mw-parser-output .cs1-subscription span,.mw-parser-output .cs1-registration span{border-bottom:1px dotted;cursor:help}.mw-parser-output .cs1-hidden-error{display:none;font-size:100%}.mw-parser-output .cs1-visible-error{display:none;font-size:100%}.mw-parser-output .cs1-subscription,.mw-parser-output .cs1-registration,.mw-parser-output .cs1-format{font-size:95%}.mw-parser-output .cs1-kern-left,.mw-parser-output .cs1-kern-wl-left{padding-left:0.2em}.mw-parser-output .cs1-kern-right,.mw-parser-output .cs1-kern-wl-right{padding-right:0.2em}
- ↑ "Sulfurous Samadhi". 02-06-2001. Check date values in: |date= (help)
- ↑ Fantegrossi, WE (2005). "Hallucinogen-like actions of 2,5-dimethoxy-4-(n)-propylthiophenethylamine (2C-T-7) in mice and rats". Psychopharmacology (Berlin). 181 (3): 496–503. Unknown parameter |coauthors= ignored (help); Unknown parameter |month= ignored (help)
- ↑ Gallardo-Godoy, A (April 7, 2005). "Sulfur-substituted alpha-alkyl phenethylamines as selective and reversible MAO-A inhibitors: biological activities, CoMFA analysis, and active site modeling". Journal of Medicinal Chemistry. 48 (7): 2407–19. Unknown parameter |coauthors= ignored (help); Check date values in: |date= (help)
- ↑ Erowid. "2C-T-7 Vault: Effects".
- ↑ East Bay Express (01-02-07). "2C-T-7's Bad Trip". Check date values in: |date= (help)
- ↑ The respondent was a 43 year old male who said that he had "ingested almost 2 grams of 2CT7 over a 7 month period," taking "a daily +1 museum dosage of 5-10mg." No tolerance was noticed. He said "I found it to be one of the most powerful cognition enhancers I've ever encountered," but mentioned that "it was difficult to stop taking 2CT7 and I used a SSRI to regain serotonin balance." Discussing the long term effects this has had on him, he says "the introspective and emotionally beneficial aspects of 2CT7 have allowed me to develop and appreciate my relationships with people. 2CT7 has also helped to remove personal obstacles that have prohibited progress in my life.", 2C-T-2 & 2C-T-7 User Surveys by Murple, Feb 6, 2001
- ↑ Partnership for a Drug-Free America. "2C-B, 2C-T-7". Retrieved 2006-10-04.
- ↑ Erowid. "Third Confirmed 2C-T-7 Death". Retrieved 2006-12-06. Unknown parameter |authorlin= ignored (help)
- ↑ Erowid. "2C-T-7 Reports Train Wrecks & Disasters". Retrieved 2006-12-06.
- ↑ DEA. "Micgrogram Bulletin Jan 2004".
- ↑ US Department of Justice. "2C-T-7 Fast Facts" (PDF). | https://www.wikidoc.org/index.php/2,5-dimethoxy-4-(n)-propylthiophenethylamine | |
60989d0eb818ff6d67e8d4d8e0647fb30059446e | wikidoc | 21 CFR | 21 CFR
# Overview
Title 21 is the portion of the Code of Federal Regulations that governs food and drugs within the United States for the Food and Drug Administration (FDA), the Drug Enforcement Administration (DEA), and the Office of National Drug Control Policy (ONDCP).
It is divided into three chapters:
- Chapter I — Food and Drug Administration
- Chapter II — Drug Enforcement Administration
- Chapter III — Office of National Drug Control Policy
# Chapter I
Most of the Chapter I regulations are based on the Federal Food, Drug, and Cosmetic Act.
Notable sections:
- 11 — electronic records and electronic signature related
- 50 Protection of human subjects in clinical trials
- 56 Institutional Review Boards that oversee clinical trials
- 58 Good Laboratory Practices (GLP) for nonclinical studies
The 100 series are regulations pertaining to food:
- 101, especially 101.9 — Nutrition facts label related
(c)(2)(ii) — Requirement to include trans fat values
(c)(8)(iv) — Vitamin and mineral values
- (c)(2)(ii) — Requirement to include trans fat values
- (c)(8)(iv) — Vitamin and mineral values
- 106-107 requirements for infant formula
- 110 et seq. cGMPs for food products
- 170 food additives
- 190 dietary supplements
The 200 and 300 series are regulations pertaining to pharmaceuticals:
- 202-203 Drug advertising and marketing
- 210 et seq. cGMPs for pharmaceuticals
- 310 et seq. Requirements for new drugs
- 328 et seq. Specific requirements for over-the-counter (OTC) drugs.
The 500 series are regulations for animal feeds and animal medications:
- 510 et seq. New animal drugs
- 556 Tolerances for residues of drugs in food animals
The 600 series covers biological products (e.g. vaccines, blood):
- 601 Licensing under section 351 of the Public Health Service Act
- 606 et seq. cGMPs for human blood and blood products
The 700 series includes the limited regulations on cosmetics:
- 701 Labeling requirements
The 800 series are for medical devices:
- 803 Medical Device Reporting
- 820 et seq. Quality system regulations (analogous to cGMP, but structured like ISO)
- 860 et seq. Listing of specific approved devices and how they are classified
The 900 series covers mammography quality requirements enforced by CDRH.
The 1000 series covers radiation emitting device (e.g. lasers, cell phones) requirements enforced by CDRH.
The 1200 series consists of rules primarily based in laws other than the Food, Drug, and Cosmetic Act:
- 1240 Rules promulgated under 361 of the Public Health Service Act on interstate control of communicable disease, such as:
Requirements for pasteurization of milk
Interstate shipment of turtles as pets.
Interstate shipment of African rodents that may carry monkeypox.
Sanitation on interstate conveyances (i.e. airplanes and ships)
- Requirements for pasteurization of milk
- Interstate shipment of turtles as pets.
- Interstate shipment of African rodents that may carry monkeypox.
- Sanitation on interstate conveyances (i.e. airplanes and ships)
- 1271 Requirements for human cells, tissues, and cellular and tissue-based products (i.e. the cGTPs).
# Chapter II
Notable sections:
- 1308 — Schedules of controlled substances
1308.03(a) — Administrative Controlled Substances Code Number
1308.11 — List of Schedule I drugs
1308.12 — List of Schedule II drugs
1308.13 — List of Schedule III drugs
1308.14 — List of Schedule IV drugs
1308.15 — List of Schedule V drugs
- 1308.03(a) — Administrative Controlled Substances Code Number
- 1308.11 — List of Schedule I drugs
- 1308.12 — List of Schedule II drugs
- 1308.13 — List of Schedule III drugs
- 1308.14 — List of Schedule IV drugs
- 1308.15 — List of Schedule V drugs
# Chapter III
Notable sections:
- 1405 Governmentwide requirements for drug-free workplaces | 21 CFR
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]
# Overview
Title 21 is the portion of the Code of Federal Regulations that governs food and drugs within the United States for the Food and Drug Administration (FDA), the Drug Enforcement Administration (DEA), and the Office of National Drug Control Policy (ONDCP).
It is divided into three chapters:
- Chapter I — Food and Drug Administration
- Chapter II — Drug Enforcement Administration
- Chapter III — Office of National Drug Control Policy
# Chapter I
Most of the Chapter I regulations are based on the Federal Food, Drug, and Cosmetic Act.
Notable sections:
- 11 — electronic records and electronic signature related
- 50 Protection of human subjects in clinical trials
- 56 Institutional Review Boards that oversee clinical trials
- 58 Good Laboratory Practices (GLP) for nonclinical studies
The 100 series are regulations pertaining to food:
- 101, especially 101.9 — Nutrition facts label related
(c)(2)(ii) — Requirement to include trans fat values
(c)(8)(iv) — Vitamin and mineral values
- (c)(2)(ii) — Requirement to include trans fat values
- (c)(8)(iv) — Vitamin and mineral values
- 106-107 requirements for infant formula
- 110 et seq. cGMPs for food products
- 170 food additives
- 190 dietary supplements
The 200 and 300 series are regulations pertaining to pharmaceuticals:
- 202-203 Drug advertising and marketing
- 210 et seq. cGMPs for pharmaceuticals
- 310 et seq. Requirements for new drugs
- 328 et seq. Specific requirements for over-the-counter (OTC) drugs.
The 500 series are regulations for animal feeds and animal medications:
- 510 et seq. New animal drugs
- 556 Tolerances for residues of drugs in food animals
The 600 series covers biological products (e.g. vaccines, blood):
- 601 Licensing under section 351 of the Public Health Service Act
- 606 et seq. cGMPs for human blood and blood products
The 700 series includes the limited regulations on cosmetics:
- 701 Labeling requirements
The 800 series are for medical devices:
- 803 Medical Device Reporting
- 820 et seq. Quality system regulations (analogous to cGMP, but structured like ISO)
- 860 et seq. Listing of specific approved devices and how they are classified
The 900 series covers mammography quality requirements enforced by CDRH.
The 1000 series covers radiation emitting device (e.g. lasers, cell phones) requirements enforced by CDRH.
The 1200 series consists of rules primarily based in laws other than the Food, Drug, and Cosmetic Act:
- 1240 Rules promulgated under 361 of the Public Health Service Act on interstate control of communicable disease, such as:
Requirements for pasteurization of milk
Interstate shipment of turtles as pets.
Interstate shipment of African rodents that may carry monkeypox.
Sanitation on interstate conveyances (i.e. airplanes and ships)
- Requirements for pasteurization of milk
- Interstate shipment of turtles as pets.
- Interstate shipment of African rodents that may carry monkeypox.
- Sanitation on interstate conveyances (i.e. airplanes and ships)
- 1271 Requirements for human cells, tissues, and cellular and tissue-based products (i.e. the cGTPs).
# Chapter II
Notable sections:
- 1308 — Schedules of controlled substances
1308.03(a) — Administrative Controlled Substances Code Number
1308.11 — List of Schedule I drugs
1308.12 — List of Schedule II drugs
1308.13 — List of Schedule III drugs
1308.14 — List of Schedule IV drugs
1308.15 — List of Schedule V drugs
- 1308.03(a) — Administrative Controlled Substances Code Number
- 1308.11 — List of Schedule I drugs
- 1308.12 — List of Schedule II drugs
- 1308.13 — List of Schedule III drugs
- 1308.14 — List of Schedule IV drugs
- 1308.15 — List of Schedule V drugs
# Chapter III
Notable sections:
- 1405 Governmentwide requirements for drug-free workplaces | https://www.wikidoc.org/index.php/21_CFR | |
ac798999279bb2356ccc06c5da7661082aca034e | wikidoc | 2C-O-4 | 2C-O-4
2C-O-4 (or 4-(i)-propoxy-2,5-dimethoxyphenethylamine) is a phenethylamine of the 2C family. It is also a positional isomer of isoproscaline and was probably first synthesized by Alexander Shulgin. It produces hallucinogenic, psychedelic, and entheogenic effects. Because of the low potency of 2C-O-4, and the inactivity of 2C-O, Shulgin felt that the 2C-O series would not be an exciting, and did not pursue any further analogues.
# Chemistry
2C-O-4 is in a class of compounds commonly known as phenethylamines, and the full chemical name is 2-(4-isopropoxy-2,5-dimethoxyphenyl)ethanamine.
# Effects
Little is known about the psychopharmacological effects of 2C-O-4. Based on the one report available in his book PiHKAL, Shulgin lists the dosage of 2C-O-4 as being >60 mg.
# Pharmacology
The mechanism that produces the hallucinogenic and entheogenic effects of 2C-O-4 is unknown.
# Dangers
The toxicity of 2C-O is not known.
# Legality
2C-O-4 is unscheduled and unregulated in the United States, however because of its close similarity in structure and effects to mescaline and 2C-T-7, possession and sale of 2C-O-4 may be subject to prosecution under the Federal Analog Act.
# Reference
- ↑ Template:CitePiHKAL | 2C-O-4
2C-O-4 (or 4-(i)-propoxy-2,5-dimethoxyphenethylamine) is a phenethylamine of the 2C family. It is also a positional isomer of isoproscaline and was probably first synthesized by Alexander Shulgin. It produces hallucinogenic, psychedelic, and entheogenic effects. Because of the low potency of 2C-O-4, and the inactivity of 2C-O, Shulgin felt that the 2C-O series would not be an exciting, and did not pursue any further analogues.
# Chemistry
2C-O-4 is in a class of compounds commonly known as phenethylamines, and the full chemical name is 2-(4-isopropoxy-2,5-dimethoxyphenyl)ethanamine.
# Effects
Little is known about the psychopharmacological effects of 2C-O-4. Based on the one report available in his book PiHKAL, Shulgin lists the dosage of 2C-O-4 as being >60 mg.[1]
# Pharmacology
The mechanism that produces the hallucinogenic and entheogenic effects of 2C-O-4 is unknown.
# Dangers
The toxicity of 2C-O is not known.
# Legality
2C-O-4 is unscheduled and unregulated in the United States, however because of its close similarity in structure and effects to mescaline and 2C-T-7, possession and sale of 2C-O-4 may be subject to prosecution under the Federal Analog Act.
# Reference
- ↑ Template:CitePiHKAL | https://www.wikidoc.org/index.php/2C-O-4 | |
ce1088a1309a1d80cd7774416b84c32c9a882d77 | wikidoc | 2C-T-2 | 2C-T-2
2C-T-2, or 2,5-dimethoxy-4-ethylthiophenethylamine, is a psychedelic and ethneogenic phenethylamine of the 2C family. It was first synthesized in 1981 by Alexander Shulgin. The drug has structural and pharmacodynamic properties similar to the drugs Mescaline, MDMA (Esctasy), and 2C-T-7.
# Dosage
In Alexander Shulgin's book PiHKAL (Phenethylamines I Have Known and Loved), the dosage range is listed as 12 to 25 mg. According to Erowid a threshold dose would be 5 mg, a light dose would range from 10-15 mg, a common dose is 16-32 mg and a strong dose would be considered to be 32-48 mg.
# Effects
Effects are similar to the related 2C-T-7, but 2C-T-2 is said to produce more of a "body-load" and other unpleasant reactions with reported reddening of the face and warm flushes. It can also be very nauseating while coming up. However, there have been no reported deaths from 2C-T-2, unlike 2C-T-7, and the psychedelic effects have been much milder. 2C-T-2 is sometimes used as a "designer drug" as it belongs to the 2C series. The onset usually starts after about an hour of ingestion and rises for about 2 hours, then the user hits the plateau. Hallucinations similar to those created by LSD, psilocybin, and other serotinergic hallucinogens are very prominent on typical 2C-T-2 doses (around 30mg are taken for strong psychedelic effects, although threshold is around 10mg. The trip is often described as being similar to LSD due to the serotoninergic effects and hallucinations, and has some aspects similar to other phenethylamines like MDMA (users sometimes have euphoric rushes) although unlike MDMA, since 2C-T-2 is a strong psychedelic, effects can be unpredictable and may be different each time the user takes the substance. 2C-T-2 should be considered equally powerful (except actual potency) to LSD and mushrooms, as it can cause harsh unwanted effects that can worsen a bad trip in a club setting. There are no known reports of neurotoxicity currently, as 2C-T-2 is a research chemical. However, it is commonly assumed that it would have the same safety level of 2C-B (since research has been done on it). Effects can last between six and eight hours.
# Pharmacology
The mechanism that produces 2C-T-2’s hallucinogenic and entheogenic effects has not been specifically established, however it is most likely to result from action as a 5-HT2A serotonin receptor agonist in the brain, a mechanism of action shared by all of the hallucinogenic tryptamines and phenethylamines for which the mechanism of action is known.
# Dangers
The toxicity of 2C-T-2 is not well documented. 2C-T-2 is considerably less potent than 2C-T-7, but it may be expected that at higher doses it would display similar toxicity to that of other phenethylamines of the 2C-T family. Other phenethylamine derivatives substituted with an alkylthio group at the 4 position such as 2C-T-7 and 4-MTA are known to act as selective monoamine oxidase A inhibitors, a side effect which can lead to lethal serotonin syndrome when combined with stimulant drugs. Most confirmed fatalities involving 2C-T drugs involve their combination with other drugs such as alcohol, ecstasy or cocaine. It is also dangerous for a person who takes certain kinds of medication, OTC or prescription, to ingest 2C-T-2. Unfortunately not much is known about contraindications.
# Law
2C-T-2 is unscheduled and uncontrolled in the United States, but possession and sales of 2C-T-2 would probably be prosecuted under the Federal Analog Act because of its structural similarities to 2C-T-7.
2C-T-2 and all other compounds featured in PiHKAL are illegal drugs in the United Kingdom.
# Reference
- ↑ Theobald, DS (September 2005). "New designer drug 2,5-dimethoxy-4-ethylthio-β-phenethylamine (2C-T-2): studies on its metabolism and toxicological detection in rat urine using gas chromatography/mass spectrometry". Journal of Mass Spectrometry. 40 (9): 1157–1172. doi:10.1002/jms.890. PMID 16041763. Unknown parameter |coauthors= ignored (help).mw-parser-output cite.citation{font-style:inherit}.mw-parser-output q{quotes:"\"""\"""'""'"}.mw-parser-output code.cs1-code{color:inherit;background:inherit;border:inherit;padding:inherit}.mw-parser-output .cs1-lock-free a{background:url("")no-repeat;background-position:right .1em center}.mw-parser-output .cs1-lock-limited a,.mw-parser-output .cs1-lock-registration a{background:url("")no-repeat;background-position:right .1em center}.mw-parser-output .cs1-lock-subscription a{background:url("")no-repeat;background-position:right .1em center}.mw-parser-output .cs1-subscription,.mw-parser-output .cs1-registration{color:#555}.mw-parser-output .cs1-subscription span,.mw-parser-output .cs1-registration span{border-bottom:1px dotted;cursor:help}.mw-parser-output .cs1-hidden-error{display:none;font-size:100%}.mw-parser-output .cs1-visible-error{display:none;font-size:100%}.mw-parser-output .cs1-subscription,.mw-parser-output .cs1-registration,.mw-parser-output .cs1-format{font-size:95%}.mw-parser-output .cs1-kern-left,.mw-parser-output .cs1-kern-wl-left{padding-left:0.2em}.mw-parser-output .cs1-kern-right,.mw-parser-output .cs1-kern-wl-right{padding-right:0.2em} | 2C-T-2
2C-T-2, or 2,5-dimethoxy-4-ethylthiophenethylamine, is a psychedelic and ethneogenic phenethylamine of the 2C family. It was first synthesized in 1981 by Alexander Shulgin.[1] The drug has structural and pharmacodynamic properties similar to the drugs Mescaline, MDMA (Esctasy), and 2C-T-7.
# Dosage
In Alexander Shulgin's book PiHKAL (Phenethylamines I Have Known and Loved), the dosage range is listed as 12 to 25 mg. According to Erowid a threshold dose would be 5 mg, a light dose would range from 10-15 mg, a common dose is 16-32 mg and a strong dose would be considered to be 32-48 mg.
# Effects
Effects are similar to the related 2C-T-7, but 2C-T-2 is said to produce more of a "body-load" and other unpleasant reactions with reported reddening of the face and warm flushes. It can also be very nauseating while coming up. However, there have been no reported deaths from 2C-T-2, unlike 2C-T-7, and the psychedelic effects have been much milder. 2C-T-2 is sometimes used as a "designer drug" as it belongs to the 2C series. The onset usually starts after about an hour of ingestion and rises for about 2 hours, then the user hits the plateau. Hallucinations similar to those created by LSD, psilocybin, and other serotinergic hallucinogens are very prominent on typical 2C-T-2 doses (around 30mg are taken for strong psychedelic effects, although threshold is around 10mg. The trip is often described as being similar to LSD due to the serotoninergic effects and hallucinations, and has some aspects similar to other phenethylamines like MDMA (users sometimes have euphoric rushes) although unlike MDMA, since 2C-T-2 is a strong psychedelic, effects can be unpredictable and may be different each time the user takes the substance. 2C-T-2 should be considered equally powerful (except actual potency) to LSD and mushrooms, as it can cause harsh unwanted effects that can worsen a bad trip in a club setting. There are no known reports of neurotoxicity currently, as 2C-T-2 is a research chemical. However, it is commonly assumed that it would have the same safety level of 2C-B (since research has been done on it). Effects can last between six and eight hours.
# Pharmacology
The mechanism that produces 2C-T-2’s hallucinogenic and entheogenic effects has not been specifically established, however it is most likely to result from action as a 5-HT2A serotonin receptor agonist in the brain, a mechanism of action shared by all of the hallucinogenic tryptamines and phenethylamines for which the mechanism of action is known.
# Dangers
The toxicity of 2C-T-2 is not well documented. 2C-T-2 is considerably less potent than 2C-T-7, but it may be expected that at higher doses it would display similar toxicity to that of other phenethylamines of the 2C-T family. Other phenethylamine derivatives substituted with an alkylthio group at the 4 position such as 2C-T-7 and 4-MTA are known to act as selective monoamine oxidase A inhibitors, a side effect which can lead to lethal serotonin syndrome when combined with stimulant drugs. Most confirmed fatalities involving 2C-T drugs involve their combination with other drugs such as alcohol, ecstasy or cocaine. It is also dangerous for a person who takes certain kinds of medication, OTC or prescription, to ingest 2C-T-2. Unfortunately not much is known about contraindications.
# Law
2C-T-2 is unscheduled and uncontrolled in the United States, but possession and sales of 2C-T-2 would probably be prosecuted under the Federal Analog Act because of its structural similarities to 2C-T-7.
2C-T-2 and all other compounds featured in PiHKAL are illegal drugs in the United Kingdom.
# Reference
- ↑ Theobald, DS (September 2005). "New designer drug 2,5-dimethoxy-4-ethylthio-β-phenethylamine (2C-T-2): studies on its metabolism and toxicological detection in rat urine using gas chromatography/mass spectrometry". Journal of Mass Spectrometry. 40 (9): 1157–1172. doi:10.1002/jms.890. PMID 16041763. Unknown parameter |coauthors= ignored (help).mw-parser-output cite.citation{font-style:inherit}.mw-parser-output q{quotes:"\"""\"""'""'"}.mw-parser-output code.cs1-code{color:inherit;background:inherit;border:inherit;padding:inherit}.mw-parser-output .cs1-lock-free a{background:url("https://upload.wikimedia.org/wikipedia/commons/thumb/6/65/Lock-green.svg/9px-Lock-green.svg.png")no-repeat;background-position:right .1em center}.mw-parser-output .cs1-lock-limited a,.mw-parser-output .cs1-lock-registration a{background:url("https://upload.wikimedia.org/wikipedia/commons/thumb/d/d6/Lock-gray-alt-2.svg/9px-Lock-gray-alt-2.svg.png")no-repeat;background-position:right .1em center}.mw-parser-output .cs1-lock-subscription a{background:url("https://upload.wikimedia.org/wikipedia/commons/thumb/a/aa/Lock-red-alt-2.svg/9px-Lock-red-alt-2.svg.png")no-repeat;background-position:right .1em center}.mw-parser-output .cs1-subscription,.mw-parser-output .cs1-registration{color:#555}.mw-parser-output .cs1-subscription span,.mw-parser-output .cs1-registration span{border-bottom:1px dotted;cursor:help}.mw-parser-output .cs1-hidden-error{display:none;font-size:100%}.mw-parser-output .cs1-visible-error{display:none;font-size:100%}.mw-parser-output .cs1-subscription,.mw-parser-output .cs1-registration,.mw-parser-output .cs1-format{font-size:95%}.mw-parser-output .cs1-kern-left,.mw-parser-output .cs1-kern-wl-left{padding-left:0.2em}.mw-parser-output .cs1-kern-right,.mw-parser-output .cs1-kern-wl-right{padding-right:0.2em}
# External links
- PiHKAL #40 2C-T-2
- 2C-T-2 vault at Erowid
Sulfurous Samadhi: An Investigation of 2C-T-2 & 2C-T-7
- Sulfurous Samadhi: An Investigation of 2C-T-2 & 2C-T-7
Template:Hallucinogenic phenethylamines
Template:PiHKAL
Template:WikiDoc Sources | https://www.wikidoc.org/index.php/2C-T-2 | |
74297e87a8025d6c559b4536d3c668872bd8b425 | wikidoc | 2C-T-4 | 2C-T-4
2C-T-4 or 2,5-dimethoxy-4-(i)-propylthiophenethylamine is a psychedelic phenethylamine of the 2C family. It was presumably first synthesized by Alexander Shulgin, sometimes used as an entheogen.
# Chemistry
2C-T-4 is the 2-carbon homologue of DOT-4, aka Aleph-4. The full chemical name is 2-[4-(isopropylthio)-2,5-dimethoxyphenylethanamine. The drug has structural and pharmacodynamic properties similar to 2C-T-7 and 2C-T-9.
# Dosage
2C-T-4 is usually taken orally, and the dosage range is typically 8-20 mg.
# Effects
2C-T-4 produces psychedelic and entheogenic effects that develop slowly and can last 8-16 hours. Some users have also reported dissociative properties uncharacteristic of other psychedelic phenethylamines. While all users experience virtually no effects for the first hour after ingestion, results vary drastically between individuals and range from hallucination and euphoria to intense sickness and anxiety.
# Pharmacology
The mechanism that produces 2C-T-4’s hallucinogenic and entheogenic effects has not been specifically established, however it is most likely to result from action as a 5-HT2A serotonin receptor agonist in the brain, a mechanism of action shared by all of the hallucinogenic tryptamines and phenethylamines for which the mechanism of action is known.
# Dangers
The toxicity of 2C-T-4 is not well documented. It may be expected that it would act in a manner similar to that of other phenethylamines, especially of the 2C-T family. Other phenethylamine derivatives substituted with an alkylthio group at the 4 position such as 2C-T-7 and 4-MTA are known to act as selective monoamine oxidase A inhibitors, a side effect which can lead to lethal serotonin syndrome when they are combined with stimulant drugs. Most confirmed fatalities involving 2C-T drugs involve their combination with other hard drugs such as alcohol, ecstasy or cocaine. To those already inebriated with alcohol, 2C-T-4 has a dangerous sobering effect that could lead chronically abusive or inexperienced users to drink until lethally poisoned. Based on the known toxicity of other drugs of this family, doses above 20 milligrams of 2C-T-4 may have a high risk of very unpleasant physiological experiences, and at doses of 30 mg or above, death from overdose might occur.
# Popularity
2C-T-4 is relatively unknown on the black market, but has been sold to a limited extent on the research chemical market.
# Legality
2C-T-4 is unscheduled and unregulated in the United States, however its close similarity in structure and effects to 2C-T-7 could potentially subject possession and sale of proscaline to prosecution under the Federal Analog Act. This seems to be the tack the federal government is taking in the wake of the DEA's Operation Web Tryp. A series of Court Cases in the US involving the prosecution of several online vendors were commenced in 2004 and resulted in several convictions.
Sweden: from May 1st 2007, 2C-T-4 is a controlled substance under the act "Lag (1999:42) om förbud mot vissa hälsofarliga varor".
# Homologue
2C-T-4 has one homologue, the structural isomer Ψ-2C-T-4 (2,6-dimethoxy-4-(i)-propylthiophenethylamine). This compound was tested by Alexander Shulgin at a dose of 12 mg.
At this dosage its duration was very short and it produced few effects, however based on the research into the better characterized compound Ψ-DOM, the potency of Ψ-2C-T-4 is likely to be around 1/3 that of 2C-T-4 itself, so a more effective dosage of Ψ-2C-T-4 might be in the region of 20-60 mg; however high doses such as this might well be associated with toxic side effects, and so extreme caution would be advised.
# Reference
- ↑ Template:CitePiHKAL
- ↑ Template:CitePiHKAL
# Categorization | 2C-T-4
2C-T-4 or 2,5-dimethoxy-4-(i)-propylthiophenethylamine is a psychedelic phenethylamine of the 2C family. It was presumably first synthesized by Alexander Shulgin, sometimes used as an entheogen.
# Chemistry
2C-T-4 is the 2-carbon homologue of DOT-4, aka Aleph-4. The full chemical name is 2-[4-(isopropylthio)-2,5-dimethoxyphenylethanamine. The drug has structural and pharmacodynamic properties similar to 2C-T-7 and 2C-T-9.
# Dosage
2C-T-4 is usually taken orally, and the dosage range is typically 8-20 mg.
# Effects
2C-T-4 produces psychedelic and entheogenic effects that develop slowly and can last 8-16 hours. Some users have also reported dissociative properties uncharacteristic of other psychedelic phenethylamines. While all users experience virtually no effects for the first hour after ingestion, results vary drastically between individuals and range from hallucination and euphoria to intense sickness and anxiety.[1]
# Pharmacology
The mechanism that produces 2C-T-4’s hallucinogenic and entheogenic effects has not been specifically established, however it is most likely to result from action as a 5-HT2A serotonin receptor agonist in the brain, a mechanism of action shared by all of the hallucinogenic tryptamines and phenethylamines for which the mechanism of action is known.
# Dangers
The toxicity of 2C-T-4 is not well documented. It may be expected that it would act in a manner similar to that of other phenethylamines, especially of the 2C-T family. Other phenethylamine derivatives substituted with an alkylthio group at the 4 position such as 2C-T-7 and 4-MTA are known to act as selective monoamine oxidase A inhibitors, a side effect which can lead to lethal serotonin syndrome when they are combined with stimulant drugs. Most confirmed fatalities involving 2C-T drugs involve their combination with other hard drugs such as alcohol, ecstasy or cocaine. To those already inebriated with alcohol, 2C-T-4 has a dangerous sobering effect that could lead chronically abusive or inexperienced users to drink until lethally poisoned. Based on the known toxicity of other drugs of this family, doses above 20 milligrams of 2C-T-4 may have a high risk of very unpleasant physiological experiences, and at doses of 30 mg or above, death from overdose might occur.
# Popularity
2C-T-4 is relatively unknown on the black market, but has been sold to a limited extent on the research chemical market.
# Legality
2C-T-4 is unscheduled and unregulated in the United States, however its close similarity in structure and effects to 2C-T-7 could potentially subject possession and sale of proscaline to prosecution under the Federal Analog Act. This seems to be the tack the federal government is taking in the wake of the DEA's Operation Web Tryp. A series of Court Cases in the US involving the prosecution of several online vendors were commenced in 2004 and resulted in several convictions.
Sweden: from May 1st 2007, 2C-T-4 is a controlled substance under the act "Lag (1999:42) om förbud mot vissa hälsofarliga varor".
# Homologue
2C-T-4 has one homologue, the structural isomer Ψ-2C-T-4 (2,6-dimethoxy-4-(i)-propylthiophenethylamine). This compound was tested by Alexander Shulgin at a dose of 12 mg.
At this dosage its duration was very short and it produced few effects, however based on the research into the better characterized compound Ψ-DOM, the potency of Ψ-2C-T-4 is likely to be around 1/3 that of 2C-T-4 itself, so a more effective dosage of Ψ-2C-T-4 might be in the region of 20-60 mg[2]; however high doses such as this might well be associated with toxic side effects, and so extreme caution would be advised.
# Reference
- ↑ Template:CitePiHKAL
- ↑ Template:CitePiHKAL
# Categorization
Template:Hallucinogenic phenethylamines
Template:PiHKAL
# External links
- PiHKAL #41 2C-T-4
Template:WikiDoc Sources | https://www.wikidoc.org/index.php/2C-T-4 | |
3f10ee8a4e525622a2847eabe9f9c3205b08071d | wikidoc | 2C-T-8 | 2C-T-8
2C-T-8 is a psychedelic phenethylamine of the 2C family. It was first synthesized by Alexander Shulgin, sometimes used as an entheogen.
# Chemistry
The full name of the chemical is 2,5-dimethoxy-4-cyclopropylmethylthiophenethylamine. The compound is reported to have a bad taste and smell.
# Effects
In his book PIHKAL (Phenethylamines I Have Known and Loved), Shulgin lists the dosage range as 30 to 50 mg. 2C-T-8 is generally taken orally, and effects typically last 10 to 15 hours. Experiences have varied between insight and creativity at low doses to hypersensitivity and paranoia at higher doses. A "thinking-connection" that is characteristic of the 2C-T group is evident in this chemical in stark contrast to the "pure euphoria" of phenethylamines such as MDMA.
# Legality
2C-T-8 is unscheduled and uncontrolled in the United States, but possession and sales of 2C-T-8 will probably be prosecuted under the Federal Analog Act because of its structural similarities to 2C-T-7. However, 2C-T-8, unlike many other phenethylamines has not been sold by internet retailers. In the wake of Operation Web Tryp in July 2004, the issue of possession and sales of 2C-T-8 and other similar chemicals will probably be resolved in the courtroom as will the fate of this rare but unique psychedelic. There have been no reported deaths from 2C-T-8.
# Pharmacology
The mechanism that produces 2C-T-8’s hallucinogenic and entheogenic effects has not been specifically established, however it is most likely to result from action as a 5-HT2A serotonin receptor agonist in the brain, a mechanism of action shared by all of the hallucinogenic tryptamines and phenethylamines for which the mechanism of action is known.
# Dangers
The toxicity of 2C-T-8 is not well documented. 2C-T-8 is somewhat less potent than 2C-T-7, but it may be expected that at higher doses it would display similar toxicity to that of other phenethylamines of the 2C-T family. Other phenethylamine derivatives substituted with an alkylthio group at the 4 position such as 2C-T-7 and 4-MTA are known to act as selective monoamine oxidase A inhibitors, a side effect which can lead to lethal serotonin syndrome when they are combined with stimulant drugs.
There have been no confirmed deaths due to 2C-T-8, though this may in part be due to its rarity and limited usage. Of the 2C-T family, there have been a few confirmed deaths due to 2C-T-7, which involved either insufflating large (30mg+) doses and in one case an unknown oral dose was combined with 200mg MDMA.
# Popularity
2C-T-8 is unknown on the black market. Limited accounts of 2C-T-8 can be found in the book PiHKAL.
# Reference
- ↑ Template:CitePiHKAL | 2C-T-8
2C-T-8 is a psychedelic phenethylamine of the 2C family. It was first synthesized by Alexander Shulgin, sometimes used as an entheogen.
# Chemistry
The full name of the chemical is 2,5-dimethoxy-4-cyclopropylmethylthiophenethylamine. The compound is reported to have a bad taste and smell.
# Effects
In his book PIHKAL (Phenethylamines I Have Known and Loved), Shulgin lists the dosage range as 30 to 50 mg. 2C-T-8 is generally taken orally, and effects typically last 10 to 15 hours. Experiences have varied between insight and creativity at low doses to hypersensitivity and paranoia at higher doses. A "thinking-connection" that is characteristic of the 2C-T group is evident in this chemical in stark contrast to the "pure euphoria" of phenethylamines such as MDMA.[1]
# Legality
2C-T-8 is unscheduled and uncontrolled in the United States, but possession and sales of 2C-T-8 will probably be prosecuted under the Federal Analog Act because of its structural similarities to 2C-T-7. However, 2C-T-8, unlike many other phenethylamines has not been sold by internet retailers. In the wake of Operation Web Tryp in July 2004, the issue of possession and sales of 2C-T-8 and other similar chemicals will probably be resolved in the courtroom as will the fate of this rare but unique psychedelic. There have been no reported deaths from 2C-T-8.
# Pharmacology
The mechanism that produces 2C-T-8’s hallucinogenic and entheogenic effects has not been specifically established, however it is most likely to result from action as a 5-HT2A serotonin receptor agonist in the brain, a mechanism of action shared by all of the hallucinogenic tryptamines and phenethylamines for which the mechanism of action is known.
# Dangers
The toxicity of 2C-T-8 is not well documented. 2C-T-8 is somewhat less potent than 2C-T-7, but it may be expected that at higher doses it would display similar toxicity to that of other phenethylamines of the 2C-T family. Other phenethylamine derivatives substituted with an alkylthio group at the 4 position such as 2C-T-7 and 4-MTA are known to act as selective monoamine oxidase A inhibitors, a side effect which can lead to lethal serotonin syndrome when they are combined with stimulant drugs.
There have been no confirmed deaths due to 2C-T-8[citation needed], though this may in part be due to its rarity and limited usage. Of the 2C-T family, there have been a few confirmed deaths due to 2C-T-7, which involved either insufflating large (30mg+) doses[1][2] and in one case an unknown oral dose was combined with 200mg MDMA[3].
# Popularity
2C-T-8 is unknown on the black market. Limited accounts of 2C-T-8 can be found in the book PiHKAL.
# Reference
- ↑ Template:CitePiHKAL
# External links
- 2C-T-8 Entry in PIHKAL
Template:Hallucinogen-stub
Template:Hallucinogenic phenethylamines
Template:PiHKAL
Template:WikiDoc Sources | https://www.wikidoc.org/index.php/2C-T-8 | |
b757cd54434db87c4c24b41ea1563539376c7d50 | wikidoc | 2C-T-9 | 2C-T-9
2C-T-9 is a psychedelic phenethylamine of the 2C family. It was first synthesized by Alexander Shulgin, sometimes used as an entheogen.
# Chemistry
2C-T-9 is 2,5-dimethoxy-4-(n)-butylthiophenethylamine.
The IUPAC name of 2C-T-9 is 1-(4-(n-butylthio)-2,5-dimethoxyphenyl)-2-aminoethane.
# Dosage
In his book PIHKAL (Phenethylamines I Have Known and Loved), Shulgin lists the dosage range as 60 - 100 mg.
# Subjective Qualities
It is generally taken orally, and effects typically last 12 to 18 hours. There have been no reported deaths from 2C-T-9. The drug is said to taste like motor oil, and experiences have focused primarily on energy as opposed to creativity or insight.
# Pharmacology
The mechanism that produces 2C-T-9’s hallucinogenic and entheogenic effects has not been specifically established, however it is most likely to result from action as a 5-HT2A serotonin receptor agonist in the brain, a mechanism of action shared by all of the hallucinogenic tryptamines and phenethylamines for which the mechanism of action is known.
# Dangers
The toxicity of 2C-T-9 is not well documented. 2C-T-9 is considerably less potent than 2C-T-7, but it may be expected that at higher doses it would display similar toxicity to that of other phenethylamines of the 2C-T family. Other phenethylamine derivatives substituted with an alkylthio group at the 4 position such as 2C-T-7 and 4-MTA are known to act as selective monoamine oxidase A inhibitors, a side effect which can lead to lethal serotonin syndrome when they are combined with stimulant drugs. Most confirmed fatalities involving 2C-T drugs involve their combination with other hard drugs such as alcohol, ecstasy or cocaine.
# Legality
2C-T-9 is not illegal, but possession and sales of 2C-T-9 could be prosecuted under the Federal Analog Act because of its structural similarities to 2C-T-7.
# Reference
- ↑ Template:CitePiHKAL | 2C-T-9
2C-T-9 is a psychedelic phenethylamine of the 2C family. It was first synthesized by Alexander Shulgin, sometimes used as an entheogen.
# Chemistry
2C-T-9 is 2,5-dimethoxy-4-(n)-butylthiophenethylamine.
The IUPAC name of 2C-T-9 is 1-(4-(n-butylthio)-2,5-dimethoxyphenyl)-2-aminoethane.
# Dosage
In his book PIHKAL (Phenethylamines I Have Known and Loved), Shulgin lists the dosage range as 60 - 100 mg.
# Subjective Qualities
It is generally taken orally, and effects typically last 12 to 18 hours.[1] There have been no reported deaths from 2C-T-9. The drug is said to taste like motor oil, and experiences have focused primarily on energy as opposed to creativity or insight.
# Pharmacology
The mechanism that produces 2C-T-9’s hallucinogenic and entheogenic effects has not been specifically established, however it is most likely to result from action as a 5-HT2A serotonin receptor agonist in the brain, a mechanism of action shared by all of the hallucinogenic tryptamines and phenethylamines for which the mechanism of action is known.
# Dangers
The toxicity of 2C-T-9 is not well documented. 2C-T-9 is considerably less potent than 2C-T-7, but it may be expected that at higher doses it would display similar toxicity to that of other phenethylamines of the 2C-T family. Other phenethylamine derivatives substituted with an alkylthio group at the 4 position such as 2C-T-7 and 4-MTA are known to act as selective monoamine oxidase A inhibitors, a side effect which can lead to lethal serotonin syndrome when they are combined with stimulant drugs. Most confirmed fatalities involving 2C-T drugs involve their combination with other hard drugs such as alcohol, ecstasy or cocaine.
# Legality
2C-T-9 is not illegal, but possession and sales of 2C-T-9 could be prosecuted under the Federal Analog Act because of its structural similarities to 2C-T-7.
# Reference
- ↑ Template:CitePiHKAL
# External links
- 2C-T-9 Entry in PIHKAL
Template:Hallucinogen-stub
Template:Hallucinogenic phenethylamines
Template:PiHKAL
Template:WikiDoc Sources | https://www.wikidoc.org/index.php/2C-T-9 | |
08e745f9128f94366efc65949b25fc45a2dc5a42 | wikidoc | 2C-TFM | 2C-TFM
2C-TFM is a psychedelic phenethylamine of the 2C family. It was first synthesized in the laboratory of David E. Nichols. It has also been called 2C-CF3, a name derived from the para-trifluoromethyl group it contains. It is sometimes used as a hallucinogen and entheogen.
# Chemistry
2C-TFM is a code that represents 4-trifluoromethyl-2,5-dimethoxyphenethylamine. The full name of the chemical is 2-ethanamine.
# Dosage
A psychedelic dosage of 2C-TFM is reported to be 3-5mg.
# Effects
Very little data exists, but some reports suggest 2C-TFM produces hallucinogenic, psychedelic, and entheogenic effects that may last 6-8 hours.
# Legality
2C-TFM is unscheduled and uncontrolled in the United States, but possession and sales of 2C-TFM will probably be prosecuted under the Federal Analog Act because of its structural similarities to 2C-B and 2C-T-7. However, 2C-TFM, unlike many other phenethylamines, has not been widely sold by internet retailers. In the wake of Operation Web Tryp in July 2004, the issue of possession and sales of 2C-TFM and other similar chemicals will probably be resolved in the courtroom as well the fate of this rare but unique psychedelic. There have been no reported deaths or hospitalizations from 2C-TFM.
# Pharmacology
The mechanism that produces the hallucinogenic and entheogenic effects of 2C-TFM is most likely to result from action as a 5-HT2A serotonin receptor agonist in the brain, a mechanism of action shared by all of the hallucinogenic tryptamines and phenethylamines. 2C-TFM displaced radiolabelled ketanserin from 5-HT2A/C receptors with a Ki of 74.5, as compared to a Ki of 80.9 for the more well known 5-HT2A agonist DOI, indicating similar binding affinity at the receptor.
# Dangers
The toxicity of 2C-TFM is not known.
# Popularity
Sale of 2C-TFM is unknown on the black market. Limited accounts of 2C-TFM can be found on the internet. Outside of David Nichols' lab, the only widely available black market 2C-TFM is known to have been less than 50% pure, with the majority of the impurity being unreacted 2C-I, as well as some undetermined minor constituents. | 2C-TFM
2C-TFM is a psychedelic phenethylamine of the 2C family. It was first synthesized in the laboratory of David E. Nichols. It has also been called 2C-CF3, a name derived from the para-trifluoromethyl group it contains. It is sometimes used as a hallucinogen and entheogen.
# Chemistry
2C-TFM is a code that represents 4-trifluoromethyl-2,5-dimethoxyphenethylamine. The full name of the chemical is 2-[2,5-dimethoxy-4-(trifluoromethyl)phenyl]ethanamine.
# Dosage
A psychedelic dosage of 2C-TFM is reported to be 3-5mg.
# Effects
Very little data exists, but some reports suggest 2C-TFM produces hallucinogenic, psychedelic, and entheogenic effects that may last 6-8 hours.
# Legality
2C-TFM is unscheduled and uncontrolled in the United States, but possession and sales of 2C-TFM will probably be prosecuted under the Federal Analog Act because of its structural similarities to 2C-B and 2C-T-7. However, 2C-TFM, unlike many other phenethylamines, has not been widely sold by internet retailers. In the wake of Operation Web Tryp in July 2004, the issue of possession and sales of 2C-TFM and other similar chemicals will probably be resolved in the courtroom as well the fate of this rare but unique psychedelic. There have been no reported deaths or hospitalizations from 2C-TFM.
# Pharmacology
The mechanism that produces the hallucinogenic and entheogenic effects of 2C-TFM is most likely to result from action as a 5-HT2A serotonin receptor agonist in the brain, a mechanism of action shared by all of the hallucinogenic tryptamines and phenethylamines. 2C-TFM displaced radiolabelled ketanserin from 5-HT2A/C receptors with a Ki of 74.5, as compared to a Ki of 80.9 for the more well known 5-HT2A agonist DOI, indicating similar binding affinity at the receptor.[1]
# Dangers
The toxicity of 2C-TFM is not known.
# Popularity
Sale of 2C-TFM is unknown on the black market. Limited accounts of 2C-TFM can be found on the internet. Outside of David Nichols' lab, the only widely available black market 2C-TFM is known to have been less than 50% pure, with the majority of the impurity being unreacted 2C-I, as well as some undetermined minor constituents.[2] | https://www.wikidoc.org/index.php/2C-TFM | |
011751431b9526537f6f34e6af40c4528feb5b61 | wikidoc | 3T3-L1 | 3T3-L1
3T3-L1 is a cell line derived from 3T3 cells that is used in bilogical research on adipose tissue. 3T3-L1 cells have a fibroblast-like morphology, but, under appropriate conditions, the cells differentiate into an adipocyte-like phenotype.
3T3-L1 cells of the adipocyte morphology increase the synthesis and accumulation of triglycerides and acquire the signet ring appearance of adipose cells. These cells are also sensitive to lipogenic and lipolytic hormones and drugs, including epinephrine, isoproterenol, and insulin.
# Sources
- ↑ Green H, Kehinde O (1975). "An established preadipose cell line and its differentiation in culture. II. Factors affecting the adipose conversion". Cell. 5 (1): 19–27. PMID 165899..mw-parser-output cite.citation{font-style:inherit}.mw-parser-output q{quotes:"\"""\"""'""'"}.mw-parser-output code.cs1-code{color:inherit;background:inherit;border:inherit;padding:inherit}.mw-parser-output .cs1-lock-free a{background:url("")no-repeat;background-position:right .1em center}.mw-parser-output .cs1-lock-limited a,.mw-parser-output .cs1-lock-registration a{background:url("")no-repeat;background-position:right .1em center}.mw-parser-output .cs1-lock-subscription a{background:url("")no-repeat;background-position:right .1em center}.mw-parser-output .cs1-subscription,.mw-parser-output .cs1-registration{color:#555}.mw-parser-output .cs1-subscription span,.mw-parser-output .cs1-registration span{border-bottom:1px dotted;cursor:help}.mw-parser-output .cs1-hidden-error{display:none;font-size:100%}.mw-parser-output .cs1-visible-error{display:none;font-size:100%}.mw-parser-output .cs1-subscription,.mw-parser-output .cs1-registration,.mw-parser-output .cs1-format{font-size:95%}.mw-parser-output .cs1-kern-left,.mw-parser-output .cs1-kern-wl-left{padding-left:0.2em}.mw-parser-output .cs1-kern-right,.mw-parser-output .cs1-kern-wl-right{padding-right:0.2em} | 3T3-L1
3T3-L1 is a cell line derived from 3T3 cells that is used in bilogical research on adipose tissue. 3T3-L1 cells have a fibroblast-like morphology, but, under appropriate conditions, the cells differentiate into an adipocyte-like phenotype.
3T3-L1 cells of the adipocyte morphology increase the synthesis and accumulation of triglycerides and acquire the signet ring appearance of adipose cells. These cells are also sensitive to lipogenic and lipolytic hormones and drugs, including epinephrine, isoproterenol, and insulin.[1]
# Sources
- ↑ Green H, Kehinde O (1975). "An established preadipose cell line and its differentiation in culture. II. Factors affecting the adipose conversion". Cell. 5 (1): 19–27. PMID 165899..mw-parser-output cite.citation{font-style:inherit}.mw-parser-output q{quotes:"\"""\"""'""'"}.mw-parser-output code.cs1-code{color:inherit;background:inherit;border:inherit;padding:inherit}.mw-parser-output .cs1-lock-free a{background:url("https://upload.wikimedia.org/wikipedia/commons/thumb/6/65/Lock-green.svg/9px-Lock-green.svg.png")no-repeat;background-position:right .1em center}.mw-parser-output .cs1-lock-limited a,.mw-parser-output .cs1-lock-registration a{background:url("https://upload.wikimedia.org/wikipedia/commons/thumb/d/d6/Lock-gray-alt-2.svg/9px-Lock-gray-alt-2.svg.png")no-repeat;background-position:right .1em center}.mw-parser-output .cs1-lock-subscription a{background:url("https://upload.wikimedia.org/wikipedia/commons/thumb/a/aa/Lock-red-alt-2.svg/9px-Lock-red-alt-2.svg.png")no-repeat;background-position:right .1em center}.mw-parser-output .cs1-subscription,.mw-parser-output .cs1-registration{color:#555}.mw-parser-output .cs1-subscription span,.mw-parser-output .cs1-registration span{border-bottom:1px dotted;cursor:help}.mw-parser-output .cs1-hidden-error{display:none;font-size:100%}.mw-parser-output .cs1-visible-error{display:none;font-size:100%}.mw-parser-output .cs1-subscription,.mw-parser-output .cs1-registration,.mw-parser-output .cs1-format{font-size:95%}.mw-parser-output .cs1-kern-left,.mw-parser-output .cs1-kern-wl-left{padding-left:0.2em}.mw-parser-output .cs1-kern-right,.mw-parser-output .cs1-kern-wl-right{padding-right:0.2em} | https://www.wikidoc.org/index.php/3T3-L1 | |
efeed5ab7865c691f2c8e104211309cf54e8be82 | wikidoc | ABCA12 | ABCA12
ATP-binding cassette sub-family A member 12 also known as ATP-binding cassette transporter 12 is a protein that in humans is encoded by the ABCA12 gene.
ABCA12 belongs to a group of genes called the ATP-binding cassette family, which makes proteins that transport molecules across cell membranes. The ABCA12 gene is active in some types of skin cells and in several other tissues, such as testis, placenta, lung, stomach, and fetal brain and liver. This protein appears to be essential for normal development of the skin, which provides a barrier between the body and its surrounding environment. It transports epidermoside, a glucosylceramide, out of the keratinocytes of the stratum corneum of the epidermis.
The ABCA12 gene is located on the long (q) arm of chromosome 2 between positions 34 and 35, from base pair 215,621,772 to base pair 215,828,656.
# Related conditions
Several mutations in the ABCA12 gene are known to cause harlequin-type ichthyosis. Most of these mutations are predicted to lead to an absence of ABCA12 protein or the production of an extremely small version of the protein that cannot transport lipids properly. A loss of functional ABCA12 protein causes numerous problems with the development of the epidermis before and after birth. Abnormalities in lipid transport prevent the skin from forming an effective barrier and result in the hard, thick scales characteristic of harlequin ichthyosis.
Mutations in the ABCA12 gene also cause another severe skin disorder, lamellar ichthyosis type 2. People with this disorder have red, scaly, plate-like skin covering most of their bodies. The ABCA12 mutations that cause this disorder substitute one amino acid (a building block of proteins) for another amino acid in the ABCA12 protein. These mutations almost always occur in an important functional region of the protein (the region that binds to ATP, a molecule that supplies energy for chemical reactions). Changes in the structure of the ABCA12 protein likely disrupt its ability to transport lipids, which affects the development of skin before and after birth. | ABCA12
ATP-binding cassette sub-family A member 12 also known as ATP-binding cassette transporter 12 is a protein that in humans is encoded by the ABCA12 gene.[1]
ABCA12 belongs to a group of genes called the ATP-binding cassette family, which makes proteins that transport molecules across cell membranes. The ABCA12 gene is active in some types of skin cells and in several other tissues, such as testis, placenta, lung, stomach, and fetal brain and liver. This protein appears to be essential for normal development of the skin, which provides a barrier between the body and its surrounding environment. It transports epidermoside, a glucosylceramide, out of the keratinocytes of the stratum corneum of the epidermis.[2]
The ABCA12 gene is located on the long (q) arm of chromosome 2 between positions 34 and 35, from base pair 215,621,772 to base pair 215,828,656.
# Related conditions
Several mutations in the ABCA12 gene are known to cause harlequin-type ichthyosis.[3] Most of these mutations are predicted to lead to an absence of ABCA12 protein or the production of an extremely small version of the protein that cannot transport lipids properly. A loss of functional ABCA12 protein causes numerous problems with the development of the epidermis before and after birth. Abnormalities in lipid transport prevent the skin from forming an effective barrier and result in the hard, thick scales characteristic of harlequin ichthyosis.
Mutations in the ABCA12 gene also cause another severe skin disorder, lamellar ichthyosis type 2.[4][5] People with this disorder have red, scaly, plate-like skin covering most of their bodies. The ABCA12 mutations that cause this disorder substitute one amino acid (a building block of proteins) for another amino acid in the ABCA12 protein. These mutations almost always occur in an important functional region of the protein (the region that binds to ATP, a molecule that supplies energy for chemical reactions). Changes in the structure of the ABCA12 protein likely disrupt its ability to transport lipids, which affects the development of skin before and after birth. | https://www.wikidoc.org/index.php/ABCA12 | |
99c829f26fb2838b828615d0a958de239615bb58 | wikidoc | ABCB11 | ABCB11
ATP-binding cassette, sub-family B member 11 also known as ABCB11 is a protein which in humans is encoded by the ABCB11 gene.
# Function
The product of the ABCB11 gene is an ABC transporter named BSEP (Bile Salt Export Pump), or sPgp (sister of P-glycoprotein). This membrane-associated protein is a member of the superfamily of ATP-binding cassette (ABC) transporters. ABC proteins transport various molecules across extra- and intra-cellular membranes. ABC genes are divided into seven distinct subfamilies (ABC1, MDR/TAP, MRP, ALD, OABP, GCN20, White).
This protein is a member of the MDR/TAP subfamily. Some members of the MDR/TAP subfamily are involved in multidrug resistance. This particular protein is responsible for the transport of taurocholate and other cholate conjugates from hepatocytes (liver cells) to the bile. In humans, the activity of this transporter is the major determinant of bile formation and bile flow.
# Clinical significance
ABCB11 is a gene associated with progressive familial intrahepatic cholestasis type 2 (PFIC2). PFIC2 caused by mutations in the ABCB11 gene increases the risk of hepatocellular carcinoma in early life. | ABCB11
ATP-binding cassette, sub-family B member 11 also known as ABCB11 is a protein which in humans is encoded by the ABCB11 gene.[1]
# Function
The product of the ABCB11 gene is an ABC transporter named BSEP (Bile Salt Export Pump), or sPgp (sister of P-glycoprotein). This membrane-associated protein is a member of the superfamily of ATP-binding cassette (ABC) transporters. ABC proteins transport various molecules across extra- and intra-cellular membranes. ABC genes are divided into seven distinct subfamilies (ABC1, MDR/TAP, MRP, ALD, OABP, GCN20, White).[2]
This protein is a member of the MDR/TAP subfamily. Some members of the MDR/TAP subfamily are involved in multidrug resistance. This particular protein is responsible for the transport of taurocholate and other cholate conjugates from hepatocytes (liver cells) to the bile. In humans, the activity of this transporter is the major determinant of bile formation and bile flow.[3][4][5][6]
# Clinical significance
ABCB11 is a gene associated with progressive familial intrahepatic cholestasis type 2 (PFIC2).[1][7][8][9] PFIC2 caused by mutations in the ABCB11 gene increases the risk of hepatocellular carcinoma in early life.[10] | https://www.wikidoc.org/index.php/ABCB11 | |
942f2767db0d6a2e461959b1d6850e6d25cead3c | wikidoc | ABCC11 | ABCC11
ATP-binding cassette transporter sub-family C member 11 is a protein that in humans is encoded by the ABCC11 gene.
The gene is responsible for determination of human cerumen type (wet or dry ear wax) and presence of underarm osmidrosis (odor associated with sweat caused by excessive apocrine secretion).
# Function
The protein encoded by this gene is a member of the superfamily of ATP-binding cassette (ABC) transporters. ABC proteins transport various molecules across extra- and intra-cellular membranes. ABC genes are divided into seven distinct subfamilies (ABC1, MDR/TAP, MRP, ALD, OABP, GCN20, White). This ABC full transporter is a member of the MRP subfamily which is involved in multi-drug resistance. The product of this gene participates in physiological processes involving bile acids, conjugated steroids, and cyclic nucleotides. In addition, an SNP in this gene is responsible for determination of human earwax type and presence of underarm odour. This gene and family member ABCC12 are determined to be derived by duplication and are both localized to chromosome 16q12.1. Multiple alternatively spliced transcript variants have been described for this gene.
# Molecular genetics
The ABCC11 gene is present in the human genome as two alleles, differing in one nucleotide also known as a single nucleotide polymorphism (SNP). A SNP in the ABCC11 gene on chromosome 16 at base position 538 of either a guanine or adenine controls for multiple distinct phenotypes. These respectively code for glycine and arginine in the gene's protein product. Dominant inheritance of the GG or GA genotype is observed while the AA genotype is recessive. The phenotypes expressed by the genotypes include cerumen type (wet or dry ear wax), osmidrosis (odor associated with sweat caused by excessive apocrine secretion), and breast cancer risk, although there is ongoing debate on whether if there is a real correlation of the wet ear wax phenotype to breast cancer susceptibility. The GG or GA genotype produces the wet ear wax phenotype (sticky and brown colored) and acrid sweat odor and is the dominant allele. Note this phenotype requires only the presence of one guanine. The homozygous recessive AA genotype produces the dry ear wax phenotype (dry and flaky) and mildly odored sweat.
The alleles containing a guanine produce a protein that is glycosylated but alleles containing an adenine are not glycosylated. The resulting protein is only partially degraded by proteasomes. This effect is localized to ceruminous gland membranes. Because the adenine containing allele protein product is only partially degraded, the remaining functional protein is located on the cell surface membrane which ABCC11 gene's role in sweat odor is likely in part due to the quantitative dosage of ABCC11 protein.
From an evolutionary perspective, the implications of cerumen type on fitness are unknown although odorless sweat in ancient Northern Eurasian populations have been postulated to have an adaptive advantage for cold weather. In some nonhuman mammals, mating signals via release of an odor enhanced by increased apocrine secretion may be a factor in sexual selection.
Physical human traits that are controlled by a single gene are uncommon. Most human characteristics are controlled by multiple genes (polygenes) although ABCC11 is a peculiar example of a gene with unambiguous phenotypes that is controlled by a SNP. Additionally, it is considered a pleiotropic gene.
# Demographics
The history of the migration of humans can be traced back using the ABCC11 gene alleles. The variation between ear wax and body odor in ethnicities around the world are specifically due to the ABCC11 gene alleles. It is hypothesized that 40,000 years ago, an ancient Mongoloid tribe evolved the dry ear wax phenotype that followed a spread of the dry ear wax allele to other regions of Asia via migration of the ancient tribe. The gene spread as a result of it being a beneficial adaption or through an evolutionary neutral mutation mechanism that went through genetic drift events.
The frequency of alleles for dry ear wax and odorless sweat is most concentrated in East- and Northeast Asia, most notably Korea, China, Mongolia, and western Japan. Conversely the frequency of the allele for wet ear wax and odored sweat are highest in African-American and sub-saharan populations. A downward gradient of dry ear wax allele phenotypes can be drawn from northern China to southern Asia and a east-west gradient can also be drawn from eastern Siberia to western Europe. The allele frequencies within ethnicities continued to be maintained because the ABCC11 gene is inherited as a haplotype, a group of genes or alleles that tend to be inherited as a single unit
The amount of volatile organic compounds (VOCs) in ear wax was found to be related to variation in ABCC11 genotype, which in turn is dependent on ethnic origin. In particular, the rs17822931 genotype, which is especially prevalent in East Asians, is correlated with lower VOC levels. | ABCC11
ATP-binding cassette transporter sub-family C member 11 is a protein that in humans is encoded by the ABCC11 gene.[1][2][3]
The gene is responsible for determination of human cerumen type (wet or dry ear wax) and presence of underarm osmidrosis (odor associated with sweat caused by excessive apocrine secretion).
# Function
The protein encoded by this gene is a member of the superfamily of ATP-binding cassette (ABC) transporters. ABC proteins transport various molecules across extra- and intra-cellular membranes. ABC genes are divided into seven distinct subfamilies (ABC1, MDR/TAP, MRP, ALD, OABP, GCN20, White). This ABC full transporter is a member of the MRP subfamily which is involved in multi-drug resistance. The product of this gene participates in physiological processes involving bile acids, conjugated steroids, and cyclic nucleotides. In addition, an SNP in this gene is responsible for determination of human earwax type and presence of underarm odour. This gene and family member ABCC12 are determined to be derived by duplication and are both localized to chromosome 16q12.1. Multiple alternatively spliced transcript variants have been described for this gene.[3]
# Molecular genetics
The ABCC11 gene is present in the human genome as two alleles, differing in one nucleotide also known as a single nucleotide polymorphism (SNP).[4] A SNP in the ABCC11 gene on chromosome 16 at base position 538 of either a guanine or adenine controls for multiple distinct phenotypes.[4][5] These respectively code for glycine and arginine in the gene's protein product. Dominant inheritance of the GG or GA genotype is observed while the AA genotype is recessive. The phenotypes expressed by the genotypes include cerumen type (wet or dry ear wax), osmidrosis (odor associated with sweat caused by excessive apocrine secretion), and breast cancer risk, although there is ongoing debate on whether if there is a real correlation of the wet ear wax phenotype to breast cancer susceptibility.[6][7] The GG or GA genotype produces the wet ear wax phenotype (sticky and brown colored) and acrid sweat odor and is the dominant allele.[6] Note this phenotype requires only the presence of one guanine. The homozygous recessive AA genotype produces the dry ear wax phenotype (dry and flaky) and mildly odored sweat.[6]
The alleles containing a guanine produce a protein that is glycosylated but alleles containing an adenine are not glycosylated. The resulting protein is only partially degraded by proteasomes.[4] This effect is localized to ceruminous gland membranes.[4] Because the adenine containing allele protein product is only partially degraded, the remaining functional protein is located on the cell surface membrane which ABCC11 gene's role in sweat odor is likely in part due to the quantitative dosage of ABCC11 protein.[4]
From an evolutionary perspective, the implications of cerumen type on fitness are unknown although odorless sweat in ancient Northern Eurasian populations have been postulated to have an adaptive advantage for cold weather.[5] In some nonhuman mammals, mating signals via release of an odor enhanced by increased apocrine secretion may be a factor in sexual selection.[5]
Physical human traits that are controlled by a single gene are uncommon. Most human characteristics are controlled by multiple genes (polygenes) although ABCC11 is a peculiar example of a gene with unambiguous phenotypes that is controlled by a SNP. Additionally, it is considered a pleiotropic gene.
# Demographics
The history of the migration of humans can be traced back using the ABCC11 gene alleles. The variation between ear wax and body odor in ethnicities around the world are specifically due to the ABCC11 gene alleles.[5] It is hypothesized that 40,000 years ago, an ancient Mongoloid tribe evolved the dry ear wax phenotype that followed a spread of the dry ear wax allele to other regions of Asia via migration of the ancient tribe.[8] The gene spread as a result of it being a beneficial adaption or through an evolutionary neutral mutation mechanism that went through genetic drift events.[8]
The frequency of alleles for dry ear wax and odorless sweat is most concentrated in East- and Northeast Asia, most notably Korea, China, Mongolia, and western Japan.[5] Conversely the frequency of the allele for wet ear wax and odored sweat are highest in African-American and sub-saharan populations.[5] A downward gradient of dry ear wax allele phenotypes can be drawn from northern China to southern Asia and a east-west gradient can also be drawn from eastern Siberia to western Europe.[5] The allele frequencies within ethnicities continued to be maintained because the ABCC11 gene is inherited as a haplotype, a group of genes or alleles that tend to be inherited as a single unit[5][9]
The amount of volatile organic compounds (VOCs) in ear wax was found to be related to variation in ABCC11 genotype, which in turn is dependent on ethnic origin. In particular, the rs17822931 genotype, which is especially prevalent in East Asians, is correlated with lower VOC levels.[10] | https://www.wikidoc.org/index.php/ABCC11 | |
4ffcc0ed9fc07c4891d7925d2e580705451835b0 | wikidoc | ABHD12 | ABHD12
alpha/beta-Hydrolase domain containing 12 (ABHD12) is a serine hydrolase encoded by the ABHD12 gene that participates in the breakdown of the endocannabinoid neurotransmitter 2-arachidonylglycerol (2-AG) in the central nervous system. It is responsible for about 9% of brain 2-AG hydrolysis. Together, ABHD12 along with two other enzymes, monoacylglycerol lipase (MAGL) and ABHD6, control 99% of 2-AG hydrolysis in the brain. ABHD12 also serves as a lysophospholipase and metabolizes lysophosphatidylserine (LPS).
# Protein structure
ABHD12 is a ~45 kDa integrated membrane glycoprotein, with an active site proposed to face into the extracellular space.
Currently, the crystal structure of ABHD12 is not known.
# Function
ABHD12 is a lysophosphatidylserine (lysoPS) lipase responsible for regulation of immune and neurological processes, and shown to act on the endocannabinoid arachidonoylglycerol (AG) as a monoacylglycerol lipase. Endocannabinoids are associated with a range of physiological processes. ABHD12 acts on 2-AG, and accounts for approximately 9% of 2-AG hydrolysis in the brain. Along with MAGL and ABHD6, ABHD12 is responsible for 99% of 2-AG hydrolysis in the brain, and has also been shown to act on the 1(3)-AG isomer. Based on the extracellular face of the ABHD12 active site and its ability to act on multiple isomeric substrates, ABHD12 has been suggested to act as a guard to the extracellular 2-AG-CB2R signalling pathway in microglia, and peripheral 2-AG signalling, however this has not been confirmed.
ABHD12 transcription is abundant in the brain, specifically microglia, but has also been identified in peripheral cell types like macrophages and osteoclasts. Murine models have shown ABHD12 plays a role in regulation of lysophosphatidylserine pathways in the brain.
# Clinical significance
Mutations that compromise the catalytic activity of ABHD12 have been causally linked to the rare neurodegenerative disease PHARC (polyneuropathy, hearing loss, ataxia, retinitis pigmentosa, cataracts) and a small proportion of retinitis pigmentosa.
# History
Identification of ABHD12 was first reported in genetic profiling of autosomal recessive retinitis pigmentosa in 1995. In 2010, mutations in ABHD12 were reported as a causal link for the neurodegenerative disease PHARC .
# Mutations
Mutations in ABHD12 are associated with the rare neurodegenerative disorder PHARC, as well as retinitis pigmentosa. Null mutations have been shown to lead to development of PHARC, while other mutations can result in a range of phenotypes, from non-syndromic retinal degeneration to PHARC.
Currently, PHARC has been identified in at least 27 individuals, with 15 identified loss of function variants of ABHD12, comprising four nonsense, four missense, four frameshift and one splicing mutation. ABHD12 missense mutations have been identified in individuals with retinitis pigmentosa, and a growing range of phenotypes associated with ABHD12 mutations from PHARC to non-syndromic retinal degeneration are being discovered.
In vitro, enzymatic activity of ABHD12 can be eliminated by site mutation the residues Serine-246, Aspartate-333, or Histidine-372, which form a catalytic triad in the hydrolase domain.
# Inhibitors
Inhibitors of ABHD12 have been identified. Orlistat (tetrahydrolipstatin; THL) and methyl arachidonyl fluorophosphonate (MAFP), so-called "universal lipase/serine hydrolase inhibitors" that are extremely non-selective enzyme inhibitors, were found to inhibit ABHD12. Selective reversible inhibitors have also been identified, including betulinic acid, maslinic acid, oleanolic acid, and ursolic acid.
# Models
The α/β hydrolase domain including lipase motif and catalytic triad is conserved between murine and human ABHD12.
Based on the observation of ABHD12 mutation in PHARC affected subjects, PHARC cell lines have been considered as human models of ABHD12 knockout.
Mouse knockout (ABHD12 -/-) models demonstrate cerebellar microgliosis, motor and auditory impairment, alongside elevated neuroinflammation with progression associated with age. These characteristics are considered PHARC-like phenotypes as a murine model for human PHARC, however the mouse knockout model doesn’t demonstrate ocular or myelination defects, or early onset typical of PHARC. The ABHD -/- murine model shows increased long-chain lysoPS accumulation in the brain suggesting lysoPS signalling contributes to PHARC-like pathology.
A zebrafish knockdown (+/-) model has been developed which demonstrates ophthalmic defects including microphthalmia, lack of lens clarity, and disrupted retina architecture.
# Interactions
Elevated lysoPS accumulation in ABHD12 knockout mice suggests lysoPS as an in vivo substrate of ABHD12. Elevated lysoPS production in ABHD12 null cells from PHARC subjects can be reversed using an inhibitor of ABHD16A.
In vitro studies demonstrate enzymatic hydrolysis of monoacylglycerol long lipid chains by ABHD12. ABHD12 can use both 1(3)-AG and 2-AG as substrates at comparable enzymatic rates.
ABHD12 has been shown to be associated with AMPA type glutamate receptors in the brains of rats. | ABHD12
alpha/beta-Hydrolase domain containing 12 (ABHD12) is a serine hydrolase encoded by the ABHD12 gene that participates in the breakdown of the endocannabinoid neurotransmitter 2-arachidonylglycerol (2-AG) in the central nervous system.[1] It is responsible for about 9% of brain 2-AG hydrolysis.[1] Together, ABHD12 along with two other enzymes, monoacylglycerol lipase (MAGL) and ABHD6, control 99% of 2-AG hydrolysis in the brain.[1] ABHD12 also serves as a lysophospholipase and metabolizes lysophosphatidylserine (LPS).[2]
# Protein structure
ABHD12 is a ~45 kDa integrated membrane glycoprotein, with an active site proposed to face into the extracellular space.[3]
Currently, the crystal structure of ABHD12 is not known.
# Function
ABHD12 is a lysophosphatidylserine (lysoPS) lipase responsible for regulation of immune and neurological processes, and shown to act on the endocannabinoid arachidonoylglycerol (AG) as a monoacylglycerol lipase.[4][5] Endocannabinoids are associated with a range of physiological processes. ABHD12 acts on 2-AG, and accounts for approximately 9% of 2-AG hydrolysis in the brain.[1] Along with MAGL and ABHD6, ABHD12 is responsible for 99% of 2-AG hydrolysis in the brain,[3] and has also been shown to act on the 1(3)-AG isomer.[5] Based on the extracellular face of the ABHD12 active site and its ability to act on multiple isomeric substrates, ABHD12 has been suggested to act as a guard to the extracellular 2-AG-CB2R signalling pathway in microglia, and peripheral 2-AG signalling, however this has not been confirmed.[5][1]
ABHD12 transcription is abundant in the brain, specifically microglia, but has also been identified in peripheral cell types like macrophages and osteoclasts.[6] Murine models have shown ABHD12 plays a role in regulation of lysophosphatidylserine pathways in the brain.[7]
# Clinical significance
Mutations that compromise the catalytic activity of ABHD12 have been causally linked to the rare neurodegenerative disease PHARC (polyneuropathy, hearing loss, ataxia, retinitis pigmentosa, cataracts)[6] and a small proportion of retinitis pigmentosa.[8][9]
# History
Identification of ABHD12 was first reported in genetic profiling of autosomal recessive retinitis pigmentosa in 1995.[8] In 2010, mutations in ABHD12 were reported as a causal link for the neurodegenerative disease PHARC .[6]
# Mutations
Mutations in ABHD12 are associated with the rare neurodegenerative disorder PHARC, as well as retinitis pigmentosa. Null mutations have been shown to lead to development of PHARC, while other mutations can result in a range of phenotypes, from non-syndromic retinal degeneration to PHARC.[10]
Currently, PHARC has been identified in at least 27 individuals, with 15 identified loss of function variants of ABHD12,[11] comprising four nonsense, four missense, four frameshift and one splicing mutation.[6][10][11][12][13][14][15] ABHD12 missense mutations have been identified in individuals with retinitis pigmentosa, and a growing range of phenotypes associated with ABHD12 mutations from PHARC to non-syndromic retinal degeneration are being discovered.[10][14]
In vitro, enzymatic activity of ABHD12 can be eliminated by site mutation the residues Serine-246, Aspartate-333, or Histidine-372, which form a catalytic triad in the hydrolase domain.[5]
# Inhibitors
Inhibitors of ABHD12 have been identified.[2] Orlistat (tetrahydrolipstatin; THL) and methyl arachidonyl fluorophosphonate (MAFP), so-called "universal lipase/serine hydrolase inhibitors" that are extremely non-selective enzyme inhibitors, were found to inhibit ABHD12.[2] Selective reversible inhibitors have also been identified, including betulinic acid, maslinic acid, oleanolic acid, and ursolic acid.[2]
# Models
The α/β hydrolase domain including lipase motif and catalytic triad is conserved between murine and human ABHD12.[7]
Based on the observation of ABHD12 mutation in PHARC affected subjects, PHARC cell lines have been considered as human models of ABHD12 knockout.[6]
Mouse knockout (ABHD12 -/-) models demonstrate cerebellar microgliosis, motor and auditory impairment, alongside elevated neuroinflammation with progression associated with age. These characteristics are considered PHARC-like phenotypes as a murine model for human PHARC, however the mouse knockout model doesn’t demonstrate ocular or myelination defects, or early onset typical of PHARC.[7] The ABHD -/- murine model shows increased long-chain lysoPS accumulation in the brain suggesting lysoPS signalling contributes to PHARC-like pathology.[7]
A zebrafish knockdown (+/-) model has been developed which demonstrates ophthalmic defects including microphthalmia, lack of lens clarity, and disrupted retina architecture.[11]
# Interactions
Elevated lysoPS accumulation in ABHD12 knockout mice suggests lysoPS as an in vivo substrate of ABHD12.[7] Elevated lysoPS production in ABHD12 null cells from PHARC subjects can be reversed using an inhibitor of ABHD16A.[16]
In vitro studies demonstrate enzymatic hydrolysis of monoacylglycerol long lipid chains by ABHD12. ABHD12 can use both 1(3)-AG and 2-AG as substrates at comparable enzymatic rates.[5]
ABHD12 has been shown to be associated with AMPA type glutamate receptors in the brains of rats.[17] | https://www.wikidoc.org/index.php/ABHD12 | |
f708b2c10417d412ca69104d3fc2c22823c7fdf2 | wikidoc | ABHD18 | ABHD18
ABHD18 is a protein that in Homo sapiens is encoded by the ABHD18 gene.
# Gene
ABHD18 is found on the positive strand of the human genome at 4q28.2. It is 74.4 kbp. The gene contains 17 exons. The longest mRNA transcript is composed of 13 exons and is 2200 base pairs.
# Homology
## Orthologs
Many orthologs to human ABHD18 have been discovered, with the most distant ortholog with high (over 90%) coverage is found in rice Oryza sativa. The protein is not found in fungi. Bacteria of the order Myxobacteria and genus Chitinimonas contain orthologous regions to the C4orf29 protein. The few bacterial homologs indicate a horizontal gene transfer event. The domain of unknown function, DUF2048, is conserved throughout orthologs.
# Protein
ABHD18 codes a 414 amino acid sequence of 46.9 kDa in humans. The predicted isoelectric point is 9.37. The domain of unknown function, DUF2048, is found from amino acid residues 25 to 414 in the precursor C4orf29 protein. This domain is part of the alpha/beta hydrolase superfamily, which comprises enzymes that catalyze fat metabolism. Predicted post-translational modifications include glycosylation at residues Ser287 and Ser319 and sumoylation at the motifs Phe240 to Gly243, Ala377 to Asp340, and Phe408 to Gly411.
# Expression
The protein product of ABHD18 in humans is predicted to be a secreted product. It is ubiquitously expressed at low to moderate levels. In humans, the protein is found at high levels the digestive tract and parathyroid gland. The homologous mouse protein 3110057O12Rik is expressed at high levels in the granule layer of the cerebellum.
# Clinical significance
ABHD18 contains highly variable numbers of Alu repeats. A low number of Alu repeats in the human ABHD18 protein is associated with increase prevalence of hepatocellular carcinoma (HCC) in Asian populations. This information is used as a genetic marker to determine genetic risk of HCC.
Swine muscle transcriptome analysis indicates high expression of ABHD18 in swine with extreme low levels of fatty acid composition. | ABHD18
ABHD18 is a protein that in Homo sapiens is encoded by the ABHD18 gene.[1]
# Gene
ABHD18 is found on the positive strand of the human genome at 4q28.2. It is 74.4 kbp. The gene contains 17 exons.[2] The longest mRNA transcript is composed of 13 exons and is 2200 base pairs.[1]
# Homology
## Orthologs
Many orthologs to human ABHD18 have been discovered, with the most distant ortholog with high (over 90%) coverage is found in rice Oryza sativa.[4] The protein is not found in fungi. Bacteria of the order Myxobacteria and genus Chitinimonas contain orthologous regions to the C4orf29 protein. The few bacterial homologs indicate a horizontal gene transfer event. The domain of unknown function, DUF2048, is conserved throughout orthologs.
# Protein
ABHD18 codes a 414 amino acid sequence of 46.9 kDa in humans. The predicted isoelectric point is 9.37.[6] The domain of unknown function, DUF2048, is found from amino acid residues 25 to 414 in the precursor C4orf29 protein.[7] This domain is part of the alpha/beta hydrolase superfamily, which comprises enzymes that catalyze fat metabolism. Predicted post-translational modifications include glycosylation at residues Ser287 and Ser319 [8] and sumoylation[9] at the motifs Phe240 to Gly243, Ala377 to Asp340, and Phe408 to Gly411.
# Expression
The protein product of ABHD18 in humans is predicted to be a secreted product. It is ubiquitously expressed at low to moderate levels.[10] In humans, the protein is found at high levels the digestive tract and parathyroid gland.[11] The homologous mouse protein 3110057O12Rik is expressed at high levels in the granule layer of the cerebellum.[12]
# Clinical significance
ABHD18 contains highly variable numbers of Alu repeats.[13] A low number of Alu repeats in the human ABHD18 protein is associated with increase prevalence of hepatocellular carcinoma (HCC) in Asian populations. This information is used as a genetic marker to determine genetic risk of HCC.[14]
Swine muscle transcriptome analysis indicates high expression of ABHD18 in swine with extreme low levels of fatty acid composition.[15] | https://www.wikidoc.org/index.php/ABHD18 | |
3daa653396c4124bb03a15c0981f62973664dc34 | wikidoc | ABLIM3 | ABLIM3
Actin-binding LIM protein 3 is a protein that in humans is encoded by the ABLIM3 gene.
# Function
The LIM domain is a double zinc finger structure that promotes protein-protein interactions. LIM domain proteins, such as ABLIM3, play roles in embryonic development, cell lineage determination, and cancer. An important paralog of this gene is LIMS1.
# Clinical relevance
Diseases associated with ABLIM3 include hepatoblastoma, and among its related super-pathways are axon guidance and DCC mediated attractive signaling. | ABLIM3
Actin-binding LIM protein 3 is a protein that in humans is encoded by the ABLIM3 gene.[1]
# Function
The LIM domain is a double zinc finger structure that promotes protein-protein interactions. LIM domain proteins, such as ABLIM3, play roles in embryonic development, cell lineage determination, and cancer.[2] An important paralog of this gene is LIMS1.
# Clinical relevance
Diseases associated with ABLIM3 include hepatoblastoma, and among its related super-pathways are axon guidance and DCC mediated attractive signaling. | https://www.wikidoc.org/index.php/ABLIM3 | |
68a06af7ec2d24d2b593105dd9b428f4c80c443b | wikidoc | ACAD10 | ACAD10
Acyl-CoA dehydrogenase family, member 10 is a protein that in humans is encoded by the ACAD10 gene.
# Structure
This gene encodes a member of the acyl-CoA dehydrogenase family of enzymes (ACADs), which participate in the beta-oxidation of fatty acids in mitochondria. The encoded enzyme contains a hydrolase domain at the N-terminal portion, a serine/threonine protein kinase catalytic domain in the central region, and a conserved ACAD domain at the C-terminus. Several alternatively spliced transcript variants of this gene have been described, but the full-length nature of some of these variants has not been determined.
# Clinical significance
In Pima people, ACAD10 has been identified as a gene associated with type 2 diabetes, insulin resistance, and impaired lipid metabolism. Specifically, two single nucleotide polymorphisms, rs601663 and rs659964, have been significantly correlated with these symptoms in a large population of both the Pima people and American Indians.
# Interactions
Using affinity capture mass spectrometry, an interaction is inferred when a bait protein is affinity captured from cell extracts by either polyclonal antibody or epitope tag and the associated interaction partner is identified by mass spectrometric methods. Using this method, ACAD10 has been shown to interact with P2RY8, NDUFA10, NTRK3, SLC2A12, LPAR4, PTH1R, COLEC10, APP, MAS1, CD79A, BSG, and Ubiquitin C. | ACAD10
Acyl-CoA dehydrogenase family, member 10 is a protein that in humans is encoded by the ACAD10 gene.[1]
# Structure
This gene encodes a member of the acyl-CoA dehydrogenase family of enzymes (ACADs), which participate in the beta-oxidation of fatty acids in mitochondria. The encoded enzyme contains a hydrolase domain at the N-terminal portion, a serine/threonine protein kinase catalytic domain in the central region, and a conserved ACAD domain at the C-terminus. Several alternatively spliced transcript variants of this gene have been described, but the full-length nature of some of these variants has not been determined.[1]
# Clinical significance
In Pima people, ACAD10 has been identified as a gene associated with type 2 diabetes, insulin resistance, and impaired lipid metabolism. Specifically, two single nucleotide polymorphisms, rs601663 and rs659964, have been significantly correlated with these symptoms in a large population of both the Pima people and American Indians.[2]
# Interactions
Using affinity capture mass spectrometry, an interaction is inferred when a bait protein is affinity captured from cell extracts by either polyclonal antibody or epitope tag and the associated interaction partner is identified by mass spectrometric methods. Using this method, ACAD10 has been shown to interact with P2RY8, NDUFA10, NTRK3, SLC2A12, LPAR4, PTH1R, COLEC10, APP, MAS1, CD79A, BSG, and Ubiquitin C.[3] | https://www.wikidoc.org/index.php/ACAD10 | |
4428509f4fcc56dfe7cb44bcc90946539a6dfeec | wikidoc | ACADSB | ACADSB
ACADSB is a human gene that encodes short/branched chain specific acyl-CoA dehydrogenase (SBCAD), an enzyme in the acyl CoA dehydrogenase family.
It can cause short/branched-chain acyl-CoA dehydrogenase deficiency.
# Structure
The human ACADSB gene is located on chromosome 10; its exact localization has been identified as 10q25-q26. The open reading frame (ORF) encodes a precursor protein that contains 431 amino acids; post-translational processing results in a mature protein with 399 amino acids. The cDNA is significantly similar to the cDNA of other members of the acyl-CoA dehydrogenase family; its structure is closest to that of short chain acyl-CoA dehydrogenase. The structure of the catalytic pocket has also been studied; position 104 at the bottom of the substrate-binding pocket has been identified as important in determining the length of the primary carbon chain that can be accommodated. Altering residues at positions 105 and 177 have been demonstrated to affect the rate of the dehydrogenation reactions.
# Function
Short/branched chain acyl-CoA dehydrogenase(ACADSB) is a member of the acyl-CoA dehydrogenase family of enzymes that catalyze the dehydrogenation of acyl-CoA derivatives in the metabolism of fatty acids or branch chained amino acids. Substrate specificity is the primary characteristic used to define members of this gene family. The ACADSB gene product has the greatest activity towards the short branched chain acyl-CoA derivative, (S)-2-methylbutyryl-CoA, but also reacts significantly with other 2-methyl branched chain substrates and with short straight chain acyl-CoAs. The encoded protein is also involved in L-leucine catabolism.
# Clinical significance
Mutations in the ACADSB gene have been associated with 2-Methylbutyryl-CoA dehydrogenase deficiency (SBCADD, also known as MBD) deficiency, an autosomal recessive metabolic disorder of impaired isoleucine degradation. Many mutations across the gene’s 10 exons have been identified, with the mutations causing exon skipping and other transcriptional and translational errors. The disorder may be detected by MS/MS-based routine newborn screening due to the heightened presence of 2-methylbutyrylcarnitine in tissue samples. The disorder may also be identified using urinary organic acid analysis, by detecting the presence of 2-methylbutyryl glycinuria. While many individuals with a mutation in this gene may be asymptomatic, some patients have been reported to have symptoms in early infancy. Infants may experience apneic episodes, generalized muscle atrophy, hypotonia, lethargy, seizures, and delayed motor development. Patients may also experience metabolic symptoms such as hypothermia and hypoglycemia. Finally, genetic polymorphisms of the ACADSB gene may also be involved in the development of hypertension in the Japanese population. | ACADSB
ACADSB is a human gene that encodes short/branched chain specific acyl-CoA dehydrogenase (SBCAD), an enzyme in the acyl CoA dehydrogenase family.
It can cause short/branched-chain acyl-CoA dehydrogenase deficiency.[1]
# Structure
The human ACADSB gene is located on chromosome 10; its exact localization has been identified as 10q25-q26.[2] The open reading frame (ORF) encodes a precursor protein that contains 431 amino acids; post-translational processing results in a mature protein with 399 amino acids. The cDNA is significantly similar to the cDNA of other members of the acyl-CoA dehydrogenase family; its structure is closest to that of short chain acyl-CoA dehydrogenase.[3] The structure of the catalytic pocket has also been studied; position 104 at the bottom of the substrate-binding pocket has been identified as important in determining the length of the primary carbon chain that can be accommodated. Altering residues at positions 105 and 177 have been demonstrated to affect the rate of the dehydrogenation reactions.[4]
# Function
Short/branched chain acyl-CoA dehydrogenase(ACADSB) is a member of the acyl-CoA dehydrogenase family of enzymes that catalyze the dehydrogenation of acyl-CoA derivatives in the metabolism of fatty acids or branch chained amino acids. Substrate specificity is the primary characteristic used to define members of this gene family. The ACADSB gene product has the greatest activity towards the short branched chain acyl-CoA derivative, (S)-2-methylbutyryl-CoA, but also reacts significantly with other 2-methyl branched chain substrates and with short straight chain acyl-CoAs.[5] The encoded protein is also involved in L-leucine catabolism.[6]
# Clinical significance
Mutations in the ACADSB gene have been associated with 2-Methylbutyryl-CoA dehydrogenase deficiency (SBCADD, also known as MBD) deficiency, an autosomal recessive metabolic disorder of impaired isoleucine degradation.[7] Many mutations across the gene’s 10 exons have been identified, with the mutations causing exon skipping and other transcriptional and translational errors. The disorder may be detected by MS/MS-based routine newborn screening due to the heightened presence of 2-methylbutyrylcarnitine in tissue samples.[8][9] The disorder may also be identified using urinary organic acid analysis, by detecting the presence of 2-methylbutyryl glycinuria.[6] While many individuals with a mutation in this gene may be asymptomatic, some patients have been reported to have symptoms in early infancy. Infants may experience apneic episodes, generalized muscle atrophy, hypotonia, lethargy, seizures, and delayed motor development. Patients may also experience metabolic symptoms such as hypothermia and hypoglycemia.[10] Finally, genetic polymorphisms of the ACADSB gene may also be involved in the development of hypertension in the Japanese population.[11] | https://www.wikidoc.org/index.php/ACADSB | |
a8d086c8b2c8644a3bab1a98ab138be6a544577b | wikidoc | ACADVL | ACADVL
Very long-chain specific acyl-CoA dehydrogenase, mitochondrial (VLCAD) is an enzyme that in humans is encoded by the ACADVL gene.
Mutations in the ACADVL are associated with very long-chain acyl-coenzyme A dehydrogenase deficiency. The protein encoded by this gene is targeted to the inner mitochondrial membrane, where it catalyzes the first step of the mitochondrial fatty acid beta-oxidation pathway. This acyl-Coenzyme A dehydrogenase is specific to long-chain and very-long-chain fatty acids. A deficiency in this gene product reduces myocardial fatty acid beta-oxidation and is associated with cardiomyopathy. Alternative splicing results in multiple transcript variants encoding different isoforms.
# Structure
The ACADVL gene contains 20 exons, and is about 5.4 kb long. VLCAD has interesting gene structure in humans, in that is located in a head-to-head structure with the DLG4 gene on Chromosome 17, and that the transcribed regions of these genes overlap. It has been shown that treatment with DEHP results in upregulation by the minimal promoter. While DLG4 and VLCAD share common regulatory elements, they each have separate and distinct tissue-specific elements that confer their function. In mice, these two genes are in a head-to-head orientation, but they do not overlap.
# Function
The VLCAD enzyme catalyzes most of fatty acid beta-oxidation by forming a C2-C3 trans-double bond in the fatty acid. VLCAD is specific to very long-chain fatty acids, typically C16-acylCoA and longer. In mice that have VLCAD deficiency, there is little to no protein hyperacetylation in the liver; this implies that the VLCAD protein is also necessary for protein acetylation in this biological system.
# Clinical significance
ACADVL is linked with very long-chain acyl-coenzyme A dehydrogenase deficiency (VLCADD), which has many symptoms, and typically presents as one of three phenotypes. The first is severe, with an early childhood onset and high mortality rate; the most common symptom is this form is cardiomyopathy. The second is a late onset childhood form, with milder symptoms that present most commonly as hypoketotic hypoglycemia. The final form presents in adulthood, and presents as isolated skeletal muscle involvement, rhabdomyolysis, and myoglobinuria, which is triggered by exercise or fasting. The disease is typically diagnosed by first performing tandem mass spectrometry on a blood sample of the patient during a period of stress, and then performing molecular genetic testing for the presence of the ACADVL gene. The deficiency is treated systematically, but certain conditions such as fasting, myocardial irritation, dehydration, and high fat diets are avoided in attempt to prevent secondary complications.
# Interactions
ACADVL has been shown to have 75 binary protein-protein interactions including 73 co-complex interactions. ACADVL appears to interact with RPSA and GPHN. | ACADVL
Very long-chain specific acyl-CoA dehydrogenase, mitochondrial (VLCAD) is an enzyme that in humans is encoded by the ACADVL gene.
Mutations in the ACADVL are associated with very long-chain acyl-coenzyme A dehydrogenase deficiency. The protein encoded by this gene is targeted to the inner mitochondrial membrane, where it catalyzes the first step of the mitochondrial fatty acid beta-oxidation pathway. This acyl-Coenzyme A dehydrogenase is specific to long-chain and very-long-chain fatty acids. A deficiency in this gene product reduces myocardial fatty acid beta-oxidation and is associated with cardiomyopathy. Alternative splicing results in multiple transcript variants encoding different isoforms.[1]
# Structure
The ACADVL gene contains 20 exons,[2] and is about 5.4 kb long.[3] VLCAD has interesting gene structure in humans, in that is located in a head-to-head structure with the DLG4 gene on Chromosome 17, and that the transcribed regions of these genes overlap. It has been shown that treatment with DEHP results in upregulation by the minimal promoter.[4] While DLG4 and VLCAD share common regulatory elements, they each have separate and distinct tissue-specific elements that confer their function. In mice, these two genes are in a head-to-head orientation, but they do not overlap.[3]
# Function
The VLCAD enzyme catalyzes most of fatty acid beta-oxidation by forming a C2-C3 trans-double bond in the fatty acid. VLCAD is specific to very long-chain fatty acids, typically C16-acylCoA and longer.[5] In mice that have VLCAD deficiency, there is little to no protein hyperacetylation in the liver; this implies that the VLCAD protein is also necessary for protein acetylation in this biological system.[6]
# Clinical significance
ACADVL is linked with very long-chain acyl-coenzyme A dehydrogenase deficiency (VLCADD), which has many symptoms, and typically presents as one of three phenotypes. The first is severe, with an early childhood onset and high mortality rate; the most common symptom is this form is cardiomyopathy. The second is a late onset childhood form, with milder symptoms that present most commonly as hypoketotic hypoglycemia. The final form presents in adulthood, and presents as isolated skeletal muscle involvement, rhabdomyolysis, and myoglobinuria, which is triggered by exercise or fasting.[7] The disease is typically diagnosed by first performing tandem mass spectrometry on a blood sample of the patient during a period of stress, and then performing molecular genetic testing for the presence of the ACADVL gene. The deficiency is treated systematically, but certain conditions such as fasting, myocardial irritation, dehydration, and high fat diets are avoided in attempt to prevent secondary complications.[8]
# Interactions
ACADVL has been shown to have 75 binary protein-protein interactions including 73 co-complex interactions. ACADVL appears to interact with RPSA and GPHN.[9] | https://www.wikidoc.org/index.php/ACADVL | |
540b7d4711755ab356565be117e45c0d72eeb7d7 | wikidoc | ACOT11 | ACOT11
Acyl-coenzyme A thioesterase 11 also known as StAR-related lipid transfer protein 14 (STARD14) is an enzyme that in humans is encoded by the ACOT11 gene. This gene encodes a protein with acyl-CoA thioesterase activity towards medium (C12) and long-chain (C18) fatty acyl-CoA substrates which relies on its StAR-related lipid transfer domain. Expression of a similar murine protein in brown adipose tissue is induced by cold exposure and repressed by warmth. Expression of the mouse protein has been associated with obesity, with higher expression found in obesity-resistant mice compared with obesity-prone mice. Alternative splicing results in two transcript variants encoding different isoforms.
# Structure
The ACOT11 gene is located on the 1st chromosome, with its specific localization being 1p32.3. It contains 18 exons.
The protein encoded by this gene contains 258 amino acids, and forms a homodimer with another chain. Its theoretical weight is 26.67 kDa. The protein contains a StAR-related transfer domain, which is a domain responsible for binding to lipids. There are 4 known ligands that bind to this homodimer: polyethylene glycol, chlorine, glycerol, and a form of TCEP.
# Function
The protein encoded by the ACOT11 gene is part of a family of Acyl-CoA thioesterases, which catalyze the hydrolysis of various Coenzyme A esters of various molecules to the free acid plus CoA. These enzymes have also been referred to in the literature as acyl-CoA hydrolases, acyl-CoA thioester hydrolases, and palmitoyl-CoA hydrolases. The reaction carried out by these enzymes is as follows:
CoA ester + H2O → free acid + coenzyme A
These enzymes use the same substrates as long-chain acyl-CoA synthetases, but have a unique purpose in that they generate the free acid and CoA, as opposed to long-chain acyl-CoA synthetases, which ligate fatty acids to CoA, to produce the CoA ester. The role of the ACOT- family of enzymes is not well understood; however, it has been suggested that they play a crucial role in regulating the intracellular levels of CoA esters, Coenzyme A, and free fatty acids. Recent studies have shown that Acyl-CoA esters have many more functions than simply an energy source. These functions include allosteric regulation of enzymes such as acetyl-CoA carboxylase, hexokinase IV, and the citrate condensing enzyme. Long-chain acyl-CoAs also regulate opening of ATP-sensitive potassium channels and activation of Calcium ATPases, thereby regulating insulin secretion. A number of other cellular events are also mediated via acyl-CoAs, for example signal transduction through protein kinase C, inhibition of retinoic acid-induced apoptosis, and involvement in budding and fusion of the endomembrane system. Acyl-CoAs also mediate protein targeting to various membranes and regulation of G protein α subunits, because they are substrates for protein acylation. In the mitochondria, acyl-CoA esters are involved in the acylation of mitochondrial NAD+ dependent dehydrogenases; because these enzymes are responsible for amino acid catabolism, this acylation renders the whole process inactive. This mechanism may provide metabolic crosstalk and act to regulate the NADH/NAD+ ratio in order to maintain optimal mitochondrial beta oxidation of fatty acids. The role of CoA esters in lipid metabolism and numerous other intracellular processes are well defined, and thus it is hypothesized that ACOT- enzymes play a role in modulating the processes these metabolites are involved in. | ACOT11
Acyl-coenzyme A thioesterase 11 also known as StAR-related lipid transfer protein 14 (STARD14) is an enzyme that in humans is encoded by the ACOT11 gene.[1][2][3][4] This gene encodes a protein with acyl-CoA thioesterase activity towards medium (C12) and long-chain (C18) fatty acyl-CoA substrates which relies on its StAR-related lipid transfer domain. Expression of a similar murine protein in brown adipose tissue is induced by cold exposure and repressed by warmth. Expression of the mouse protein has been associated with obesity, with higher expression found in obesity-resistant mice compared with obesity-prone mice. Alternative splicing results in two transcript variants encoding different isoforms.[4]
# Structure
The ACOT11 gene is located on the 1st chromosome, with its specific localization being 1p32.3. It contains 18 exons.[4]
The protein encoded by this gene contains 258 amino acids, and forms a homodimer with another chain. Its theoretical weight is 26.67 kDa.[5] The protein contains a StAR-related transfer domain, which is a domain responsible for binding to lipids. There are 4 known ligands that bind to this homodimer: polyethylene glycol, chlorine, glycerol, and a form of TCEP.[6]
# Function
The protein encoded by the ACOT11 gene is part of a family of Acyl-CoA thioesterases, which catalyze the hydrolysis of various Coenzyme A esters of various molecules to the free acid plus CoA. These enzymes have also been referred to in the literature as acyl-CoA hydrolases, acyl-CoA thioester hydrolases, and palmitoyl-CoA hydrolases. The reaction carried out by these enzymes is as follows:
CoA ester + H2O → free acid + coenzyme A
These enzymes use the same substrates as long-chain acyl-CoA synthetases, but have a unique purpose in that they generate the free acid and CoA, as opposed to long-chain acyl-CoA synthetases, which ligate fatty acids to CoA, to produce the CoA ester.[7] The role of the ACOT- family of enzymes is not well understood; however, it has been suggested that they play a crucial role in regulating the intracellular levels of CoA esters, Coenzyme A, and free fatty acids. Recent studies have shown that Acyl-CoA esters have many more functions than simply an energy source. These functions include allosteric regulation of enzymes such as acetyl-CoA carboxylase,[8] hexokinase IV,[9] and the citrate condensing enzyme. Long-chain acyl-CoAs also regulate opening of ATP-sensitive potassium channels and activation of Calcium ATPases, thereby regulating insulin secretion.[10] A number of other cellular events are also mediated via acyl-CoAs, for example signal transduction through protein kinase C, inhibition of retinoic acid-induced apoptosis, and involvement in budding and fusion of the endomembrane system.[11][12][13] Acyl-CoAs also mediate protein targeting to various membranes and regulation of G protein α subunits, because they are substrates for protein acylation.[14] In the mitochondria, acyl-CoA esters are involved in the acylation of mitochondrial NAD+ dependent dehydrogenases; because these enzymes are responsible for amino acid catabolism, this acylation renders the whole process inactive. This mechanism may provide metabolic crosstalk and act to regulate the NADH/NAD+ ratio in order to maintain optimal mitochondrial beta oxidation of fatty acids.[15] The role of CoA esters in lipid metabolism and numerous other intracellular processes are well defined, and thus it is hypothesized that ACOT- enzymes play a role in modulating the processes these metabolites are involved in.[16] | https://www.wikidoc.org/index.php/ACOT11 | |
7035cdc8181de9c32928c67809e6a69fbefe8794 | wikidoc | ACOT13 | ACOT13
Acyl-CoA thioesterase 13 is a protein that in humans is encoded by the ACOT13 gene. This gene encodes a member of the thioesterase superfamily. In humans, the protein co-localizes with microtubules and is essential for sustained cell proliferation.
# Structure
The orthologous mouse protein forms a homotetramer and is associated with mitochondria. The mouse protein functions as a medium- and long-chain acyl-CoA thioesterase. Multiple transcript variants encoding different isoforms have been found for this gene.
# Function
The protein encoded by the ACOT13 gene is part of a family of Acyl-CoA thioesterases, which catalyze the hydrolysis of various Coenzyme A esters of various molecules to the free acid plus CoA. These enzymes have also been referred to in the literature as acyl-CoA hydrolases, acyl-CoA thioester hydrolases, and palmitoyl-CoA hydrolases. The reaction carried out by these enzymes is as follows:
CoA ester + H2O → free acid + coenzyme A
These enzymes use the same substrates as long-chain acyl-CoA synthetases, but have a unique purpose in that they generate the free acid and CoA, as opposed to long-chain acyl-CoA synthetases, which ligate fatty acids to CoA, to produce the CoA ester. The role of the ACOT- family of enzymes is not well understood; however, it has been suggested that they play a crucial role in regulating the intracellular levels of CoA esters, Coenzyme A, and free fatty acids. Recent studies have shown that Acyl-CoA esters have many more functions than simply an energy source. These functions include allosteric regulation of enzymes such as acetyl-CoA carboxylase, hexokinase IV, and the citrate condensing enzyme. Long-chain acyl-CoAs also regulate opening of ATP-sensitive potassium channels and activation of Calcium ATPases, thereby regulating insulin secretion. A number of other cellular events are also mediated via acyl-CoAs, for example signal transduction through protein kinase C, inhibition of retinoic acid-induced apoptosis, and involvement in budding and fusion of the endomembrane system. Acyl-CoAs also mediate protein targeting to various membranes and regulation of G Protein α subunits, because they are substrates for protein acylation. In the mitochondria, acyl-CoA esters are involved in the acylation of mitochondrial NAD+ dependent dehydrogenases; because these enzymes are responsible for amino acid catabolism, this acylation renders the whole process inactive. This mechanism may provide metabolic crosstalk and act to regulate the NADH/NAD+ ratio in order to maintain optimal mitochondrial beta oxidation of fatty acids. The role of CoA esters in lipid metabolism and numerous other intracellular processes are well defined, and thus it is hypothesized that ACOT- enzymes play a role in modulating the processes these metabolites are involved in. | ACOT13
Acyl-CoA thioesterase 13 is a protein that in humans is encoded by the ACOT13 gene.[1] This gene encodes a member of the thioesterase superfamily. In humans, the protein co-localizes with microtubules and is essential for sustained cell proliferation.[1]
# Structure
The orthologous mouse protein forms a homotetramer and is associated with mitochondria. The mouse protein functions as a medium- and long-chain acyl-CoA thioesterase. Multiple transcript variants encoding different isoforms have been found for this gene.[1]
# Function
The protein encoded by the ACOT13 gene is part of a family of Acyl-CoA thioesterases, which catalyze the hydrolysis of various Coenzyme A esters of various molecules to the free acid plus CoA. These enzymes have also been referred to in the literature as acyl-CoA hydrolases, acyl-CoA thioester hydrolases, and palmitoyl-CoA hydrolases. The reaction carried out by these enzymes is as follows:
CoA ester + H2O → free acid + coenzyme A
These enzymes use the same substrates as long-chain acyl-CoA synthetases, but have a unique purpose in that they generate the free acid and CoA, as opposed to long-chain acyl-CoA synthetases, which ligate fatty acids to CoA, to produce the CoA ester.[2] The role of the ACOT- family of enzymes is not well understood; however, it has been suggested that they play a crucial role in regulating the intracellular levels of CoA esters, Coenzyme A, and free fatty acids. Recent studies have shown that Acyl-CoA esters have many more functions than simply an energy source. These functions include allosteric regulation of enzymes such as acetyl-CoA carboxylase,[3] hexokinase IV,[4] and the citrate condensing enzyme. Long-chain acyl-CoAs also regulate opening of ATP-sensitive potassium channels and activation of Calcium ATPases, thereby regulating insulin secretion.[5] A number of other cellular events are also mediated via acyl-CoAs, for example signal transduction through protein kinase C, inhibition of retinoic acid-induced apoptosis, and involvement in budding and fusion of the endomembrane system.[6][7][8] Acyl-CoAs also mediate protein targeting to various membranes and regulation of G Protein α subunits, because they are substrates for protein acylation.[9] In the mitochondria, acyl-CoA esters are involved in the acylation of mitochondrial NAD+ dependent dehydrogenases; because these enzymes are responsible for amino acid catabolism, this acylation renders the whole process inactive. This mechanism may provide metabolic crosstalk and act to regulate the NADH/NAD+ ratio in order to maintain optimal mitochondrial beta oxidation of fatty acids.[10] The role of CoA esters in lipid metabolism and numerous other intracellular processes are well defined, and thus it is hypothesized that ACOT- enzymes play a role in modulating the processes these metabolites are involved in.[11] | https://www.wikidoc.org/index.php/ACOT13 | |
e7122f37878f2788759d3c23c986d986a017e145 | wikidoc | ACTL6A | ACTL6A
Actin-like protein 6A is a protein that in humans is encoded by the ACTL6A gene.
# Function
This gene encodes a family member of actin-related proteins (ARPs), which share significant amino acid sequence identity to conventional actins. Both actins and ARPs have an actin fold, which is an ATP-binding cleft, as a common feature. The ARPs are involved in diverse cellular processes, including vesicular transport, spindle orientation, nuclear migration and chromatin remodeling. This gene encodes a 53 kDa subunit protein of the BAF (BRG1/brm-associated factor) complex in mammals, which is functionally related to SWI/SNF complex in S. cerevisiae and Drosophila; the latter is thought to facilitate transcriptional activation of specific genes by antagonizing chromatin-mediated transcriptional repression. Together with beta-actin, it is required for maximal ATPase activity of BRG1, and for the association of the BAF complex with chromatin/matrix. Three transcript variants that encode two different protein isoforms have been described.
# Clinical significance
ACTL6A is amplified in head and squamous cancers and confers poor prognosis in patients. In hepatocellular carcinomas, it promotes metastasis.
# Interactions
ACTL6A has been shown to interact with SMARCA2, Myc, Transformation/transcription domain-associated protein, RuvB-like 1 and SMARCA4. | ACTL6A
Actin-like protein 6A is a protein that in humans is encoded by the ACTL6A gene.[1][2][3]
# Function
This gene encodes a family member of actin-related proteins (ARPs), which share significant amino acid sequence identity to conventional actins. Both actins and ARPs have an actin fold, which is an ATP-binding cleft, as a common feature. The ARPs are involved in diverse cellular processes, including vesicular transport, spindle orientation, nuclear migration and chromatin remodeling. This gene encodes a 53 kDa subunit protein of the BAF (BRG1/brm-associated factor) complex in mammals, which is functionally related to SWI/SNF complex in S. cerevisiae and Drosophila; the latter is thought to facilitate transcriptional activation of specific genes by antagonizing chromatin-mediated transcriptional repression. Together with beta-actin, it is required for maximal ATPase activity of BRG1, and for the association of the BAF complex with chromatin/matrix. Three transcript variants that encode two different protein isoforms have been described.[3]
# Clinical significance
ACTL6A is amplified in head and squamous cancers and confers poor prognosis in patients.[4] In hepatocellular carcinomas, it promotes metastasis.[5]
# Interactions
ACTL6A has been shown to interact with SMARCA2,[6][7][8] Myc,[7] Transformation/transcription domain-associated protein,[7] RuvB-like 1[7] and SMARCA4.[1][6] | https://www.wikidoc.org/index.php/ACTL6A | |
0bbd0a619d92423333bff97806c910c84e04a00a | wikidoc | ACTR1A | ACTR1A
Alpha-centractin (yeast) or ARP1 is a protein that in humans is encoded by the ACTR1A gene.
# Function
This gene encodes a 42.6 kD subunit of dynactin, a macromolecular complex consisting of 10-11 subunits ranging in size from 22 to 150 kD. Dynactin binds to both microtubules and cytoplasmic dynein. It is involved in a diverse array of cellular functions, including ER-to-Golgi transport, the centripetal movement of lysosomes and endosomes, spindle formation, chromosome movement, nuclear positioning, and axonogenesis. This subunit is present in 8-13 copies per dynactin molecule, and is the most abundant molecule in the dynactin complex. It is an actin-related protein, and is approximately 60% identical at the amino acid level to conventional actin. ARP1 forms a 37 nm filament-like structure and is the core of the dynactin complex. It only exists in the dynactin complex in vivo. Highly purified, native Arp1 polymerize rapidly at extremely low concentrations into short filaments in vitro that were similar, but not identical, in length to those in dynactin. With time, these Arp1 filaments appeared to anneal to form longer assemblies but never attained the length of conventional actin filaments. As for conventional actin, Arp1 can bind and hydrolyze ATP, and Arp1 assembly is accompanied by nucleotide hydrolysis.
It has been reported that Arp1 interacts with other dynactin components including DCTN1/p150Glued,DCTN4/p62 and Actr10/Arp11. Arp1 has been shown as the domain for dynactin binding to membrane vesicles (such as Golgi or late endosome) through its association with β-spectrin.
# Interactions
ACTR1A has been shown to interact with SPTBN2. | ACTR1A
Alpha-centractin (yeast) or ARP1 is a protein that in humans is encoded by the ACTR1A gene.[1][2]
# Function
This gene encodes a 42.6 kD subunit of dynactin, a macromolecular complex consisting of 10-11 subunits ranging in size from 22 to 150 kD. Dynactin binds to both microtubules and cytoplasmic dynein. It is involved in a diverse array of cellular functions, including ER-to-Golgi transport, the centripetal movement of lysosomes and endosomes, spindle formation, chromosome movement, nuclear positioning, and axonogenesis. This subunit is present in 8-13 copies per dynactin molecule, and is the most abundant molecule in the dynactin complex. It is an actin-related protein, and is approximately 60% identical at the amino acid level to conventional actin.[2] ARP1 forms a 37 nm filament-like structure and is the core of the dynactin complex.[3] It only exists in the dynactin complex in vivo. Highly purified, native Arp1 polymerize rapidly at extremely low concentrations into short filaments in vitro that were similar, but not identical, in length to those in dynactin. With time, these Arp1 filaments appeared to anneal to form longer assemblies but never attained the length of conventional actin filaments. As for conventional actin, Arp1 can bind and hydrolyze ATP, and Arp1 assembly is accompanied by nucleotide hydrolysis.[4]
It has been reported that Arp1 interacts with other dynactin components including DCTN1/p150Glued,[5]DCTN4/p62[6][7] and Actr10/Arp11.[8] Arp1 has been shown as the domain for dynactin binding to membrane vesicles (such as Golgi or late endosome) through its association with β-spectrin.[9][10][11][12]
# Interactions
ACTR1A has been shown to interact with SPTBN2.[10][13] | https://www.wikidoc.org/index.php/ACTR1A |
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