text
stringlengths 105
4.57k
| label
int64 0
1
| label_text
stringclasses 2
values |
|---|---|---|
Κ-casein, or kappa casein, is a mammalian milk protein involved in several important physiological processes. Chymosin (found in rennet) splits K-casein into an insoluble peptide (para kappa-casein) and water-soluble glycomacropeptide (GMP). GMP is responsible for an increased efficiency of digestion, prevention of neonate hypersensitivity to ingested proteins, and inhibition of gastric pathogens. The human gene for κ-casein is CSN3. | 1 | Applied and Interdisciplinary Chemistry |
Cyclodextrin (CD) chiral stationary phase is produced by partial degradation of starch by the enzyme cyclodextrin glycosyltransferase, followed by enzymatic coupling of the glucose units, forming a toroidal structure. CDs are cyclic oligosaccharides consisting of six (α CDs), seven (β CDs) and eight (γ CDs) glucopyranose units. The chiral recognition mechanism is based on a sort of inclusion complexation. Complexation involves the interaction of the hydrophobic portion of an analyte enantiomer with the non-polar interior of the cavity, while the polar functional groups can form a hydrogen bond with the polar hydroxyl chiral cavity space. The most important factor that determines whether the analyte molecule will fit into the cyclodextrin cavity is its size. The α-CD consists of 30 stereo-selective centers, β-CD consists of 35 stereo-selective centers and γ-CD consists of 40 stereo-selective centers. When the hydrophobic portion of the analyte is larger or smaller than the toroid's cavity size, inclusion will not occur. | 0 | Theoretical and Fundamental Chemistry |
Protactinium-231 occurs naturally in uranium ores such as pitchblende, to the extent of 3 ppm in some ores. Protactinium is naturally present in soil, rock, surface water, groundwater, plants and animals in very low concentrations (on the order of 1 ppt or 0.1 picocuries (pCi)/g). | 0 | Theoretical and Fundamental Chemistry |
* Provides water for plants and animals: Water vapour gets converted to rain and snow that serve as a natural source of water for plants and animals.
* Controls evaporation: Excess water vapor in the air decreases the rate of evaporation.
* Determines climatic conditions: Excess water vapor in the air produces rain, fog, snow etc. Hence, it determines climatic conditions. | 1 | Applied and Interdisciplinary Chemistry |
Acute lymphoblastic leukemia (ALL) is a blood cancer of malignant B lymphocytes (termed B-cell ALL) or T lymphocytes (termed T-cell ALL) that typically occurs in infants and young children. In a three population-representative cohort study, NUTM1 gene rearrangements (i.e. fusion genes) occurred in 0.28 to 0.86% of pediatric patients with B-cell ALL. Among a total of 71 NUTM1-rearranged cases, 10 fusion partners of NUTM1 were identified: ACIN1-NUTM1 (24 cases), BRD9-NUTM1 (10 cases), CUX1-NUTM1 (15 cases), ZNF618-NUTM1 (9 cases; ZNF618 is the zinc finger protein 618 gene) fusion genes, and (in 1 to 4 cases each) AFF1-NUTM1, C17orf78-NUTM1 (C17orf78 is also termed ATAD5), CHD4-NUTM1, RUNX1-NUTM1, IKZF1-NUTM1, and SLC12A6-NUTM1 fusion genes. Individuals with these NUTM1 fusion gene-associated leukemias had appreciably better prognoses than those who had NUTM1 fusion gene negative B-cell acute lymphoblastic leukemias. It is thought that the cited fusion genes contribute to the development and/or progression of these NUTM1 fusion gene-associated ALL cases but the molecular mechanism(s) for this is unknown. Some HOXA genes, particularly HOXA9, are upregulated in these NUTM1 fusion gene-associated ALL cases as well as in cases of NUTM1 fusion gene-negative ALL. Further studies are required to determine if the overexpression of one or more HOXA genes contributes to NUTM1 fusion gene-associated B-cell ALL. | 1 | Applied and Interdisciplinary Chemistry |
Peter Trefonas (born 1958) is a retired DuPont Fellow (a senior scientist) at DuPont, where he had worked on the development of electronic materials. He is known for innovations in the chemistry of photolithography, particularly the development of anti-reflective coatings and polymer photoresists that are used to create circuitry for computer chips. This work has supported the patterning of smaller features during the lithographic process, increasing miniaturization and microprocessor speed. | 0 | Theoretical and Fundamental Chemistry |
Lithium amides are usually prepared in the laboratory through the addition of a titrated solution of n-butyllithium in hexanes to a solution of the amine in ether. Dry glassware and inert atmosphere are required for these reactions. Alternatively, lithium amides may be prepared by the direct action of lithium on the corresponding amine. Typical temperatures for isomerization reactions employing lithium amides are between 0 °C and reflux (ether/hexane solvent mixtures derived from the synthesis of the lithium amide are usually used directly for isomerization reactions). An excess of the base is employed to account for impurities that consume base and reaction of the base with the ether solvent. Care should be taken when HMPA is added to lithium amide reactions, as it is a known animal carcinogen.
Organolithium reagents may also be used; however, lower temperatures are required to avoid decomposition of the base. These reactions are most often run in hexanes.
Aluminum amides, which are bulkier and sometimes more selective than lithium amides, are prepared from the corresponding lithium amides and diethylaluminum chloride. Reactions are usually carried out at 0 °C in an inert atmosphere, with benzene as the solvent. | 0 | Theoretical and Fundamental Chemistry |
Cantarella was a poison allegedly used by the Borgias during the papacy of Pope Alexander VI. It may have been arsenic, came in the shape of "a white powder with a pleasant taste", and was sprinkled on food or in wine. If it did exist, it left no trace in the works of contemporary writers. | 1 | Applied and Interdisciplinary Chemistry |
Adrenergic means "working on adrenaline (epinephrine) or noradrenaline (norepinephrine)" (or on their receptors). When not further qualified, it is usually used in the sense of enhancing or mimicking the effects of epinephrine and norepinephrine in the body.
*Adrenergic nervous system, a part of the autonomic nervous system that uses epinephrine or norepinephrine as its neurotransmitter
Regarding proteins:
* Adrenergic receptor, a receptor type for epinephrine and norepinephrine; subtypes include α, α, β, β, and β receptors
* Adrenergic transporter (norepinephrine transporter), a protein transporting norepinephrine from the synaptic cleft into nerve cells
Regarding pharmaceutical drugs:
* Adrenergic receptor agonist, a type of drug activating one or more subtypes of adrenergic receptors
** This includes drugs regulating blood pressure and antiasthmatic drugs.
* Adrenergic receptor antagonist, a type of drug blocking one or more subtypes of adrenergic receptors
** This mainly includes drugs lowering blood pressure.
* Adrenergic reuptake inhibitor, a type of drug blocking the norepinephrine transporter
** This includes antidepressants and drugs against ADHD. | 1 | Applied and Interdisciplinary Chemistry |
Surface integrity is the surface condition of a workpiece after being modified by a manufacturing process. The term was coined by Michael Field and John F. Kahles in 1964.
The surface integrity of a workpiece or item changes the material's properties. The consequences of changes to surface integrity are a mechanical engineering design problem, but the preservation of those properties are a manufacturing consideration.
Surface integrity can have a great impact on a parts function; for example, Inconel 718 can have a fatigue limit as high as after a gentle grinding or as low as after electrical discharge machining (EDM). | 1 | Applied and Interdisciplinary Chemistry |
The Mongols and their rise in world history as well as conflicts with both the Jin and Song played a key role in the evolution of gunpowder technology. Mongol aptitude in incorporating foreign experts extended to the Chinese, who provided artisans that followed Mongol armies willingly and unwillingly far into the west and even east, to Japan. Unfortunately textual evidence for this is scant as the Mongols left few documents. This lack of primary source documents has caused some historians and scholars such as Kate Raphael to doubt the Mongol's role in disseminating gunpowder throughout Eurasia. On the opposite side stand historians such as Tonio Andrade and Stephen Haw, who believe that the Mongol Empire not only used gunpowder weapons but deserves the moniker "the first gunpowder empire." | 1 | Applied and Interdisciplinary Chemistry |
Hepatocyte nuclear factors (HNFs) are a group of phylogenetically unrelated transcription factors that regulate the transcription of a diverse group of genes into proteins. These proteins include blood clotting factors and in addition, enzymes and transporters involved with glucose, cholesterol, and fatty acid transport and metabolism. | 1 | Applied and Interdisciplinary Chemistry |
The rigid rotor is a good starting point from which to construct a model of a rotating molecule. It is assumed that component atoms are point masses connected by rigid bonds. A linear molecule lies on a single axis and each atom moves on the surface of a sphere around the centre of mass. The two degrees of rotational freedom correspond to the spherical coordinates θ and φ which describe the direction of the molecular axis, and the quantum state is determined by two quantum numbers J and M. J defines the magnitude of the rotational angular momentum, and M its component about an axis fixed in space, such as an external electric or magnetic field. In the absence of external fields, the energy depends only on J. Under the rigid rotor model, the rotational energy levels, F(J), of the molecule can be expressed as,
where is the rotational constant of the molecule and is related to the moment of inertia of the molecule. In a linear molecule the moment of inertia about an axis perpendicular to the molecular axis is unique, that is, , so
For a diatomic molecule
where m and m are the masses of the atoms and d is the distance between them.
Selection rules dictate that during emission or absorption the rotational quantum number has to change by unity; i.e., . Thus, the locations of the lines in a rotational spectrum will be given by
where denotes the lower level and denotes the upper level involved in the transition.
The diagram illustrates rotational transitions that obey the =1 selection rule. The dashed lines show how these transitions map onto features that can be observed experimentally. Adjacent transitions are separated by 2B in the observed spectrum. Frequency or wavenumber units can also be used for the x axis of this plot. | 0 | Theoretical and Fundamental Chemistry |
For calculating concentrations, an ICE table can be used. ICE stands for initial, change, and equilibrium.
The pH of a weak acid solution being titrated with a strong base solution can be found at different points along the way. These points fall into one of four categories:
# initial pH
# pH before the equivalence point
# pH at the equivalence point
# pH after the equivalence point
1. The initial pH is approximated for a weak acid solution in water using the equation:
where is the initial concentration of the hydronium ion.
2. The pH before the equivalence point depends on the amount of weak acid remaining and the amount of conjugate base formed. The pH can be calculated approximately by the Henderson–Hasselbalch equation: where K is the acid dissociation constant.
3. The pH at the equivalence point depends on how much the weak acid is consumed to be converted into its conjugate base. Note that when an acid neutralizes a base, the pH may or may not be neutral (pH = 7). The pH depends on the strengths of the acid and base. In the case of a weak acid and strong base titration, the pH is greater than 7 at the equivalence point. Thus pH can be calculated using the following formula:
Where is the concentration of the hydroxide ion. The concentration of the hydroxide ion is calculated from the concentration of the hydronium ion and using the following relationship:
Where K is the base dissociation constant, K is the water dissociation constant.
4. The pH after the equivalence point depends on the concentration of the conjugate base of the weak acid and the strong base of the titrant. However, the base of the titrant is stronger than the conjugate base of the acid. Therefore, the pH in this region is controlled by the strong base. As such the pH can be found using the following:
where is the concentration of the strong base that is added, is the volume of base added until the equilibrium, is the concentration of the strong acid that is added, and is the initial volume of the acid. | 0 | Theoretical and Fundamental Chemistry |
The minimum temperature and maximum density of a cloud in a magneto-optical trap is limited by the spontaneously emitted photon in cooling each cycle. While the asymmetry in atom excitation gives cooling and trapping forces, the emission of the spontaneously emitted photon is in a random direction, and therefore contributes to a heating of the atom. Of the two ħk kicks the atom receives in each cooling cycle, the first cools, and the second heats: a simple description of laser cooling which enables us to calculate a point at which these two effects reach equilibrium, and therefore define a lower temperature limit, known as the Doppler cooling limit.
The density is also limited by the spontaneously emitted photon. As the density of the cloud increases, the chance that the spontaneously emitted photon will leave the cloud without interacting with any further atoms tends to zero. The absorption, by a neighboring atom, of a spontaneously emitted photon gives a 2ħk momentum kick between the emitting and absorbing atom which can be seen as a repulsive force, similar to coulomb repulsion, which limits the maximum density of the cloud.
As of 2022 the method has been demonstrated to work up to triatomic molecules. | 0 | Theoretical and Fundamental Chemistry |
Construction of a genomic library involves creating many recombinant DNA molecules. An organisms genomic DNA is extracted and then digested with a restriction enzyme. For organisms with very small genomes (~10 kb)', the digested fragments can be separated by gel electrophoresis. The separated fragments can then be excised and cloned into the vector separately. However, when a large genome is digested with a restriction enzyme, there are far too many fragments to excise individually. The entire set of fragments must be cloned together with the vector, and separation of clones can occur after. In either case, the fragments are ligated into a vector that has been digested with the same restriction enzyme. The vector containing the inserted fragments of genomic DNA can then be introduced into a host organism.
Below are the steps for creating a genomic library from a large genome.
# Extract and purify DNA.
# Digest the DNA with a restriction enzyme. This creates fragments that are similar in size, each containing one or more genes.
# Insert the fragments of DNA into vectors that were cut with the same restriction enzyme. Use the enzyme DNA ligase to seal the DNA fragments into the vector. This creates a large pool of recombinant molecules.
# These recombinant molecules are taken up by a host bacterium by transformation, creating a DNA library.
Below is a diagram of the above outlined steps. | 1 | Applied and Interdisciplinary Chemistry |
The earliest work in RNA structural biology coincided, more or less, with the work being done on DNA in the early 1950s. In their seminal 1953 paper, Watson and Crick suggested that van der Waals crowding by the 2`OH group of ribose would preclude RNA from adopting a double helical structure identical to the model they proposed—what we now know as B-form DNA. This provoked questions about the three-dimensional structure of RNA: could this molecule form some type of helical structure, and if so, how? As with DNA, early structural work on RNA centered around isolation of native RNA polymers for fiber diffraction analysis. In part because of heterogeneity of the samples tested, early fiber diffraction patterns were usually ambiguous and not readily interpretable. In 1955, Marianne Grunberg-Manago and colleagues published a paper describing the enzyme polynucleotide phosphorylase, which cleaved a phosphate group from nucleotide diphosphates to catalyze their polymerization. This discovery allowed researchers to synthesize homogenous nucleotide polymers, which they then combined to produce double stranded molecules. These samples yielded the most readily interpretable fiber diffraction patterns yet obtained, suggesting an ordered, helical structure for cognate, double stranded RNA that differed from that observed in DNA. These results paved the way for a series of investigations into the various properties and propensities of RNA. Through the late 1950s and early 1960s, numerous papers were published on various topics in RNA structure, including RNA-DNA hybridization, triple stranded RNA, and even small-scale crystallography of RNA di-nucleotides—G-C, and A-U—in primitive helix-like arrangements. For a more in-depth review of the early work in RNA structural biology, see the article The Era of RNA Awakening: Structural biology of RNA in the early years by Alexander Rich. | 1 | Applied and Interdisciplinary Chemistry |
It is common to place a drop of the test solution on a metal disk which is then dried out to give a uniform coating on the disk. This is then used as the test sample. If the thickness of the layer formed on the disk is too thick then the lines of the spectrum are broadened to lower energies. This is because some of the energy of the alpha particles is lost during their movement through the layer of active material. | 0 | Theoretical and Fundamental Chemistry |
Phytobenthos form biofilm with other microbial populations, including heterotrophic bacteria, which can also produce extracellular polymeric substance to help establish biofilm. Within these diverse communities, phytobenthos sustains the heterotrophs and mixotrophs not only by serving as food themselves. Phytobenthos can fix organic matters as primary producers, and the extracellular polymeric substance they produced to attach themselves to surfaces can also be utilized by bacteria as another potential carbon source. The presence of consumers are not the only biotic factors driving changes to the phytobenthos composition in the community. Photosynthetic populations that demonstrate themselves to be competitive can also change the benthic community makeup. The diatom D. geminata can proliferate quickly and are readily adaptive to changes to the aquatic environment.
Researchers have assigned trophic values or indicators based on the Periphyton Index of Trophic status (PIT) to phytobenthos as another means to determine the ecological status of water bodies. Researchers have also taken into consideration of the water chemistry, richness of the community, and biomass in their studies. Depending on the site of study, researchers also account for the activities from the phytobenthos when calculating for primary productivity. | 0 | Theoretical and Fundamental Chemistry |
Between 100 million and 280 million tons of phosphogypsum waste are estimated to be produced annually as a consequence of the processing of phosphate rock for the production of phosphate fertilizers. In addition to being useless and abundant, phosphogypsum is radioactive due to the presence of naturally occurring uranium and thorium, and their daughter isotopes. Depending on the price achievable on the uranium market, extraction of the uranium content may be economically lucrative even absent other incentives, such as reducing the harm the radioactive heavy metals do to the environment. | 1 | Applied and Interdisciplinary Chemistry |
For imides derived from ammonia, the N–H center is weakly acidic. Thus, alkali metal salts of imides can be prepared by conventional bases such as potassium hydroxide. The conjugate base of phthalimide is potassium phthalimide. These anion can be alkylated to give N-alkylimides, which in turn can be degraded to release the primary amine. Strong nucleophiles, such as potassium hydroxide or hydrazine are used in the release step.
Treatment of imides with halogens and base gives the N-halo derivatives. Examples that are useful in organic synthesis are N-chlorosuccinimide and N-bromosuccinimide, which respectively serve as sources of "Cl" and "Br" in organic synthesis. | 0 | Theoretical and Fundamental Chemistry |
The chapter 9 of Tattvartha Sutra states how karmic particles can be stopped from attaching to the soul and how these can be shed. Umaswati asserts that gupti (curbing activity), dharma (virtues such as forbearance, modesty, purity, truthfulness, self-restraint, austerity, renunciation), contemplation, endurance in hardship (he lists twenty two hardships including hunger, thirst, cold, heat, nakedness, injury, lack of gain, illness, praise, disrespect), and with good character towards others (he lists five – equanimity, reinitiation, non-injury (Ahimsa), slight passion and fair conduct), a soul stops karmic accumulations. External austerities such as fasting, reduced diet and isolated habitation, along with internal austerities such as expiation, reverence, service, renunciation and meditation, according to Umaswati, along with respectful service to teachers and ailing ascetics help shed karma.
The state of liberation is presented in Chapter 10 by Umaswati. It is achieved when deluding and obstructive karmas have been destroyed. This leads to the state of quietism and potentiality, and the soul then moves to the end of the universe, states Umaswati. | 1 | Applied and Interdisciplinary Chemistry |
Robert Boyle coined the term Factitious Air upon isolating hydrogen in 1670. Henry Cavendish (1731–1810) used the term "factitious air" to refer to "any kind of air which is contained in other bodies in an unelastic state, and is produced from thence by art".
An archaic definition from 1747 for the production of factitious air was defined as being caused by: "1- by flow Degrees from Putrefactions and Fermentations of all Kinds; or 2- more expeditiously by some Sorts of chymical Dissolutions of Bodies; or 3- and lastly, almost instantaneously by the Explosion of Gunpowder, and the Mixture or some Kinds of Bodies. Thus, if Paste or Dough with Leaven be placed in an exhausted Receiver, it will, after some Time, by Fermentation, produce a considerable quantity of Air, which will appear very plainly by the Sinking the Quicksilver in the Gage. Thus also any Animal or Vegetable Substance, putrifying in Vacuo, will produce the same Effect."
There are significant inconsistencies in the archaic nomenclature due to the limited knowledge of chemistry and primitive analytical technology of the era (i.e. based on the chemistry, it is clear the terms were mistakenly assigned to more than one gas by different investigators). Furthermore, in most cases the gases were not pure. | 1 | Applied and Interdisciplinary Chemistry |
* Diabetic neuropathy
* Antidepressant
* Postherpetic neuralgia
* Premature ejaculation
* Adjunct to local anesthesia | 0 | Theoretical and Fundamental Chemistry |
Some of the unsolved problems include:
* Off-target effects – The possibility of unwanted, likely harmful, changes to the genome present a large barrier to the widespread implementation of this technology. Improvements to the specificity of gRNAs and Cas enzymes present viable solutions to this issue as well as the refinement of the delivery method of CRISPR. It is likely that different diseases will benefit from different delivery methods.
* Short-lived nature – Before gene therapy can become a permanent cure for a condition, the therapeutic DNA introduced into target cells must remain functional and the cells containing the therapeutic DNA must be stable. Problems with integrating therapeutic DNA into the nuclear genome and the rapidly dividing nature of many cells prevent it from achieving long-term benefits. Patients require multiple treatments.
* Immune response – Any time a foreign object is introduced into human tissues, the immune system is stimulated to attack the invader. Stimulating the immune system in a way that reduces gene therapy effectiveness is possible. The immune system's enhanced response to viruses that it has seen before reduces the effectiveness to repeated treatments.
* Problems with viral vectors – Viral vectors carry the risks of toxicity, inflammatory responses, and gene control and targeting issues.
* Multigene disorders – Some commonly occurring disorders, such as heart disease, high blood pressure, Alzheimer's disease, arthritis, and diabetes, are affected by variations in multiple genes, which complicate gene therapy.
* Some therapies may breach the Weismann barrier (between soma and germ-line) protecting the testes, potentially modifying the germline, falling afoul of regulations in countries that prohibit the latter practice.
* Insertional mutagenesis – If the DNA is integrated in a sensitive spot in the genome, for example in a tumor suppressor gene, the therapy could induce a tumor. This has occurred in clinical trials for X-linked severe combined immunodeficiency (X-SCID) patients, in which hematopoietic stem cells were transduced with a corrective transgene using a retrovirus, and this led to the development of T cell leukemia in 3 of 20 patients. One possible solution is to add a functional tumor suppressor gene to the DNA to be integrated. This may be problematic since the longer the DNA is, the harder it is to integrate into cell genomes. CRISPR technology allows researchers to make much more precise genome changes at exact locations.
* Cost – Alipogene tiparvovec or Glybera, for example, at a cost of $1.6 million per patient, was reported in 2013, to be the world's most expensive drug. | 1 | Applied and Interdisciplinary Chemistry |
The Official Methods of Analysis (OMA) program is AOAC's premier program for developing food testing analytical science methods that are recognized and legally defensible worldwide. | 0 | Theoretical and Fundamental Chemistry |
Key to modeling the topology of a material are the special points along k-vector of the Brillouin zone, accounting for the accurate depiction of the density of states emerging from the electronics of the material. Density functional theory (DFT) analyses predicted an indirect band gap of 0.158 eV in the β-BiI phase with the valence and conduction band maxima localized at the Γ and M k-space points, respectively. Interestingly enough, the major contributors to the band structure around the Fermi level are bismuth's p orbitals of even and odd parity, thus giving the gerade and ungerade points of symmetry. | 0 | Theoretical and Fundamental Chemistry |
Phosphine is used as a dopant in the semiconductor industry, and a precursor for the deposition of compound semiconductors. Commercially significant products include gallium phosphide and indium phosphide. | 0 | Theoretical and Fundamental Chemistry |
Coordination polymerization is a chain polymerization that involves the preliminary coordination of a monomer molecule with a chain carrier. The monomer is first coordinated with the transition metal active center, and then the activated monomer is inserted into the transition metal-carbon bond for chain growth. In some cases, coordination polymerization is also called insertion polymerization or complexing polymerization.
Advanced coordination polymerizations can control the tacticity, molecular weight and PDI of the polymer effectively. In addition, the racemic mixture of the chiral metallocene can be separated into its enantiomers. The oligomerization reaction produces an optically active branched olefin using an optically active catalyst. | 0 | Theoretical and Fundamental Chemistry |
Another use for the procedure is the affinity purification of antibodies from blood serum. If the serum is known to contain antibodies against a specific antigen (for example if the serum comes from an organism immunized against the antigen concerned) then it can be used for the affinity purification of that antigen. This is also known as Immunoaffinity Chromatography. For example, if an organism is immunised against a GST-fusion protein it will produce antibodies against the fusion-protein, and possibly antibodies against the GST tag as well. The protein can then be covalently coupled to a solid support such as agarose and used as an affinity ligand in purifications of antibody from immune serum.
For thoroughness, the GST protein and the GST-fusion protein can each be coupled separately. The serum is initially allowed to bind to the GST affinity matrix. This will remove antibodies against the GST part of the fusion protein. The serum is then separated from the solid support and allowed to bind to the GST-fusion protein matrix. This allows any antibodies that recognize the antigen to be captured on the solid support. Elution of the antibodies of interest is most often achieved using a low pH buffer such as glycine pH 2.8. The eluate is collected into a neutral tris or phosphate buffer, to neutralize the low pH elution buffer and halt any degradation of the antibody's activity. This is a nice example as affinity purification is used to purify the initial GST-fusion protein, to remove the undesirable anti-GST antibodies from the serum and to purify the target antibody.
Monoclonal antibodies can also be selected to bind proteins with great specificity, where protein is released under fairly gentle conditions. This can become of use for further research in the future.
A simplified strategy is often employed to purify antibodies generated against peptide antigens. When the peptide antigens are produced synthetically, a terminal cysteine residue is added at either the N- or C-terminus of the peptide. This cysteine residue contains a sulfhydryl functional group which allows the peptide to be easily conjugated to a carrier protein (e.g. Keyhole limpet hemocyanin (KLH)). The same cysteine-containing peptide is also immobilized onto an agarose resin through the cysteine residue and is then used to purify the antibody.
Most monoclonal antibodies have been purified using affinity chromatography based on immunoglobulin-specific Protein A or Protein G, derived from bacteria.
Immunoaffinity chromatography with monoclonal antibodies immobilized on monolithic column has been successfully used to capture extracellular vesicles (e.g., exosomes and exomeres) from human blood plasma by targeting tetraspanins and integrins found on the surface of the EVs.
Immunoaffinity chromatography is also the basis for immunochromatographic test (ICT) strips, which provide a rapid means of diagnosis in patient care. Using ICT, a technician can make a determination at a patient's bedside, without the need for a laboratory. ICT detection is highly specific to the microbe causing an infection. | 0 | Theoretical and Fundamental Chemistry |
There are certain advantages of using sinters as opposed to using other materials which include recycling the fines and other waste products, to include flue dust, mill scale, lime dust and sludge. Processing sinter helps eliminate raw flux, which is a binding material used to agglomerate materials, which saves the heating material, coke, and improves furnace productivity.
Improvements and efficiency can be gained from higher softening temperature and narrower softening in the melting zone, which increases the volume of the granular zone and shrinks the width of the cohesive zone. A lower silica content and higher hot metal temperature contributes to more sulphur removal. | 1 | Applied and Interdisciplinary Chemistry |
Because of the electronegative nitrogen in the pyridine ring, pyridine enters less readily into electrophilic aromatic substitution reactions than benzene derivatives. Instead, in terms of its reactivity, pyridine resembles nitrobenzene.
Correspondingly pyridine is more prone to nucleophilic substitution, as evidenced by the ease of metalation by strong organometallic bases. The reactivity of pyridine can be distinguished for three chemical groups. With electrophiles, electrophilic substitution takes place where pyridine expresses aromatic properties. With nucleophiles, pyridine reacts at positions 2 and 4 and thus behaves similar to imines and carbonyls. The reaction with many Lewis acids results in the addition to the nitrogen atom of pyridine, which is similar to the reactivity of tertiary amines. The ability of pyridine and its derivatives to oxidize, forming amine oxides (N-oxides), is also a feature of tertiary amines.
The nitrogen center of pyridine features a basic lone pair of electrons. This lone pair does not overlap with the aromatic π-system ring, consequently pyridine is basic, having chemical properties similar to those of tertiary amines. Protonation gives pyridinium, CHNH.The pK of the conjugate acid (the pyridinium cation) is 5.25. The structures of pyridine and pyridinium are almost identical. The pyridinium cation is isoelectronic with benzene. Pyridinium p-toluenesulfonate (PPTS) is an illustrative pyridinium salt; it is produced by treating pyridine with p-toluenesulfonic acid. In addition to protonation, pyridine undergoes N-centred alkylation, acylation, and N-oxidation. Pyridine and poly(4-vinyl) pyridine have been shown to form conducting molecular wires with remarkable polyenimine structure on UV irradiation, a process which accounts for at least some of the visible light absorption by aged pyridine samples. These wires have been theoretically predicted to be both highly efficient electron donors and acceptors, and yet are resistant to air oxidation. | 0 | Theoretical and Fundamental Chemistry |
Ligand efficiency is a measurement of the binding energy per atom of a ligand to its binding partner, such as a receptor or enzyme.
Ligand efficiency is used in drug discovery research programs to assist in narrowing focus to lead compounds with optimal combinations of physicochemical properties and pharmacological properties.
Mathematically, ligand efficiency (LE) can be defined as the ratio of Gibbs free energy (ΔG) to the number of non-hydrogen atoms of the compound:
:LE = -(ΔG)/N
where ΔG = −RTlnK and N is the number of non-hydrogen atoms. It can be transformed to the equation:
:LE = 1.4(−log IC)/N | 1 | Applied and Interdisciplinary Chemistry |
The first benchtop detector was introduced in 2014 with detection capabilities between 120 - 240 nm. This portion of the ultraviolet spectrum had historically been restricted to bright source synchrotron facilities due to significant background absorption challenges inherent to working within the wavelength range. Further detector platform development has extended the wavelength detection range out from 120 - 430 nm. | 0 | Theoretical and Fundamental Chemistry |
Modern ellipsometers are complex instruments that incorporate a wide variety of radiation sources, detectors, digital electronics and software. The range of wavelength employed is far in excess of what is visible so strictly these are no longer optical instruments. | 0 | Theoretical and Fundamental Chemistry |
The book starts with an introductory chapter devoted to definitions and principles. It then follows with 28 additional chapters, each covering a principal chemical engineering unit operation. The 28 chapters are grouped into four major sections:
* Fluid mechanics
* Heat transfer
* Mass transfer and equilibrium stages
* Operations involving particulate solids.
A more detailed table of contents is available on the Internet. | 1 | Applied and Interdisciplinary Chemistry |
Charge modulation microscopy is a new technology which combines the confocal microscopy with charge modulation spectroscopy. Unlike the charge modulation spectroscopy which is focused on the whole transistor, the charge modulation microscopy give us the local spectra and map. Thanks for this technology, the channel spectra and electrode spectra can be obtained individually. A more local dimension of charge modulation spectra (around submicrometer) can be observed without a significant Electro-absorption feature. Of course, this depends on the resolution of the optical microscopy.
The high resolution of charge modulation microscopy allows mapping of the charge carrier distribution at the active channel of the organic field-effect transistor. In other words, a functional carrier morphology can be observed. It is well known that the local carrier density can be related to the polymer microstructure. Based on Density functional theory calculations, a polarized charge modulation microscopy can selectively map the charge transport associated with a relative direction of the transition dipole moment. The local direction can be correlated to the orientational order of polymer domains. More ordered domains show a high carrier mobility of the organic field-effect transistor device. | 0 | Theoretical and Fundamental Chemistry |
Open defecation is common in south Asia, but human waste is an often overlooked source of nutrient pollution in marine pollution modeling. When nitrogen (N) and phosphorus (P) contributed by human waste was included in models for Bangladesh, India, and Pakistan, the estimated N and P inputs to bodies of water increased one to two orders of magnitude compared to previous models. River export of nutrients to coastal seas increases coastal eutrophication potential (ICEP). The ICEP of the Godavari River is three times higher when N and P inputs from human waste are included. | 0 | Theoretical and Fundamental Chemistry |
Laser shocking during the initial development stages was severely limited by the laser technology of the time period. The pulsed laser used by Battelle encompassed one large room and required several minutes of recovery time between laser pulses. To become a viable, economical, and practical industrial process, the laser technology had to mature into equipment with a much smaller footprint and be capable of increased laser pulse frequencies. In the early 1980s, Wagner Castings Company located in Decatur, Illinois became interested in laser peening as a process that could potentially increase the fatigue strength of cast iron to compete with steel, but at a lower cost. Laser peening of various cast irons showed modest fatigue life improvement, and these results along with others, convinced them to fund the design and construction of a pre-prototype pulsed laser in 1986 to demonstrate the industrial viability of the process. This laser was completed and demonstrated in 1987. Although the technology had been under investigation and development for about 15 years, few people in industry had heard of it. So, with the completion of the demonstration laser, a major marketing effort was launched by Wagner Castings and Battelle engineers to introduce laser peening to potential industrial markets.
Also in the mid 1980s, Remy Fabbro of the Ecole Polytechnique was initiating a laser shock peening program in Paris. He and Jean Fournier of the Peugeot Company visited Battelle in 1986 for an extended discussion of laser shock peening with Allan Clauer. The programs initiated by Fabbro and carried forward in the 1990s and early 2000s by Patrice Peyre, Laurent Berthe, and co-workers have made major contributions, both theoretical and experimental, to the understanding and implementation of laser peening. In 1998, they measured using VISAR (Velocimeter Interferometer System for Any Reflector) pressure loadings in water confinement regime as function of wavelength. They demonstrate the detrimental effect of breakdown in water limiting maximum pressure at the surface of material. | 1 | Applied and Interdisciplinary Chemistry |
Polymers blends, composites, multilayer films and fibers AFM-IR has been used to identify and map polymer components in blends, characterize interfaces in composites, and even reverse engineer multilayer films Additionally AFM-IR has been used to study chemical composition in Poly(3][4-ethylenedioxythiophene) (PEDOT) conducting polymers. and vapor infiltration into polyethylene terephthalate PET fibers. | 0 | Theoretical and Fundamental Chemistry |
For many substances, the formation reaction may be considered as the sum of a number of simpler reactions, either real or fictitious. The enthalpy of reaction can then be analyzed by applying Hesss Law, which states that the sum' of the enthalpy changes for a number of individual reaction steps equals the enthalpy change of the overall reaction. This is true because enthalpy is a state function, whose value for an overall process depends only on the initial and final states and not on any intermediate states. Examples are given in the following sections. | 0 | Theoretical and Fundamental Chemistry |
# Glucose + oxygen + water --(enzyme glucose oxidase)--> gluconate + hydrogen peroxide
# Hydrogen peroxide + ABTS --(enzyme peroxidase)--> colored complex
In this case, both stages of the reaction are catalyzed by enzymes. | 0 | Theoretical and Fundamental Chemistry |
To modify the performance of lecithin to make it suitable for the product to which it is added, it may be hydrolysed enzymatically. In hydrolysed lecithins, a portion of the phospholipids have one fatty acid removed by phospholipase. Such phospholipids are called lysophospholipids. The most commonly used phospholipase is phospholipase A2, which removes the fatty acid at the C2 position of glycerol. Lecithins may also be modified by a process called fractionation. During this process, lecithin is mixed with an alcohol, usually ethanol. Some phospholipids, such as phosphatidylcholine, have good solubility in ethanol, whereas most other phospholipids do not dissolve well in ethanol. The ethanol is separated from the lecithin sludge, after which the ethanol is removed by evaporation to obtain a phosphatidylcholine-enriched lecithin fraction. | 0 | Theoretical and Fundamental Chemistry |
Research in 2014, suggested that favipiravir may have efficacy against Ebola based on studies in mouse models; efficacy in humans was unaddressed.
During the 2014 West Africa Ebola virus outbreak, a French nurse who contracted Ebola while volunteering for Médecins Sans Frontières (MSF) in Liberia reportedly recovered after receiving a course of favipiravir. A clinical trial investigating the use of favipiravir against Ebola virus disease began in Guéckédou, Guinea, in December 2014. Preliminary results presented in 2016 at the Conference on Retroviruses and Opportunistic Infections (CROI), later published, showed a decrease in mortality in patients with low-to-moderate levels of virus in blood, but no effect on patients with high levels (the group at a higher risk of death). The trial design was concomitantly criticised for using only historical controls. | 0 | Theoretical and Fundamental Chemistry |
Photooxygenation of indolizines (heterocyclic aromatic derivates of indole) has been investigated in both mechanistic and synthetic contexts. Rather than proceeding through a Type I or Type II photooxygenation mechanism, some investigators have chosen to use 9,10-dicyanoanthracene (DCA) as a photosensitizer, leading to the reaction of an indolizine derivative with the superoxide anion radical. Note that the reaction proceeds through an indolizine radical cation intermediate that has not been isolated (and thus is not depicted): | 0 | Theoretical and Fundamental Chemistry |
The outcomes of manganese-mediated coupling reactions depend on both the structure of the substrate(s) and the reaction conditions. This section describes the scope and limitations of inter- and intramolecular manganese-mediated radical coupling reactions and is organized according to the carbonyl compound employed as the substrate.
Intermolecular reactions between ketones/aldehydes and alkenes tend to result in low yields. In the absence of copper(II) acetate, hydrogen atom abstraction occurs, yielding saturated ketones or aldehydes.
When Cu(OAc) is present, further oxidation to carbocations followed by elimination takes place, leading to the formation of β,γ-unsaturated carbonyl compounds in moderate yields.
Aromatic compounds are also useful radical acceptors in manganese(III)-mediated coupling reactions. Furan reacts selectively at the α position to afford substituted products in high yield.
Lactonization of alkenes in the presence of acetic acid and acetate salts is a synthetically useful method for the synthesis of γ-lactones. Selectivity is high for the radical addition that leads to the more stable adduct radical, and trans lactones are selectively formed from either cis or trans acyclic alkenes.
β-Dicarbonyl compounds are useful substrates for the formation of dihydrofurans. Copper(II) acetate is not necessary in this case because of the high resonance stabilization of the intermediate diphenylmethyl radical.
When alkenes or carbonyl compounds containing pendant unsaturated moiety are treated with manganese(III) acetate, tandem intramolecular cyclization reactions may occur. Generally, exo cyclization of terminal double bonds is favored, as shown in equation (10). A variety of substitution patterns may be employed for this transformation, and yields are generally higher than intermolecular coupling reactions.
The stereochemical course of tandem reactions can be understood in some cases by invoking a chairlike transition state with as many substituents as possible in pseudoequatorial positions; however, a number of examples exhibiting unpredictable stereochemistry are known.
Nitriles are useful as radical acceptors in tandem cyclizations. Hydrolysis of the resulting imine leads to polycyclic ketones in moderate yields with good stereoselectivity. | 0 | Theoretical and Fundamental Chemistry |
* Charlesby A. Atomic Radiation and Polymers. Pergamon Press, Oxford, pp. 198–257 (1960).
* Gall, K; Dunn, M; Liu, Y. Internal stress storage in shape shape-memory polymer nanocomposites. Applied physical letters. 85, (Jul-2004).
* Jeong, Han Mo; Song H, Chi W. Shape-shape-memory effect of poly (methylene-1,3-cyclopentane) and its copolymer with polyethylene. Polymer International, 51:275-280 (2002).
* Kawate, K. Creep Recovery of Acrylate Urethane Oligomer/Acrylate Networks. Creep recovery, shape shape-memory. Journal of polymer science. 35.
* Kim B K, Lee S Y, Xu M. Polyurethanes having shape-shape-memory effects. Polymer 37: 5781–93, (1998).
* Langer, R; Tirrell, D. A. Designing materials for biology and medicine. Nature 428: (Apr-2004).
* Lendlein, A; Kelch, S; Kratz, K. Shape-shape-memory Polymers. Encyclopedia of Materials: Science and Technology. 1–9. (2005).
* Lendlein, A; Langer, R. Biodegradable, elastic shape-shape-memory polymers for potential biomedical applications. Science. 296, 1673–1676 (2002).
* Lendlein, A; Kelch, S. Shape-Memory Polymers. Angew. Chemie. Chem. Int. 41: 2034 – 2057. (2002).
* Lendlein, A; Schmidt, A M; Langer R, AB-polymer networks based on oligo(ε-caprolactone) segments showing shape-shape-memory properties. Proc. Natl. Acad. Sci. USA. 98(3): 842–7 (2001).
* Li F, Chen Y, Zhu W, Zhang X, Xu M. Shape shape-memory effects of polyethylene/nylon 6 graft copolymers. Polymer 39(26):6929–6934 (1998).
* Liu, Chun, Mather. Chemically Cross-Linked Polycyclooctene: Synthesis, Characterization, and Shape Memory Behavior. Macromolecules, 35: 9868-9874 (2002).
* Nakasima A, Hu J, Ichinosa M, Shimada H. Potential application of shape-shape-memory plastic as elastic material in clinical orthodontics. (1991) Eur. J. Orthodontics 13:179–86.
* Ortega, Alicia M; Gall, Ken. The Effect of Crosslink Density on the Thermo-Mechanical Response of Shape Memory Polymers.
* Peng P; Wang, W; Xuesi C; and Jing X. Poly(ε-caprolactone) Polyurethane and Its Shape-Memory Property. Biomacromolecules 6:587-592 (2005).
* Wang, M; Zhang, L. Recovery as a Measure of Oriented Crystalline Structure in Poly (ether ester) s Based on Poly (ethylene oxide) and poly(ethylene terephthalate) Used as Shape Memory Polymers. Journal of Polymer Science: Part B: Polymer Physics, 37: 101–112 (1999).
* Yiping C. Ying G; Juan D; Juan L; Yuxing P; Albert S. Hydrogen-bonded polymer network—poly (ethylene glycol) complexes with shape shape-memory effect. Journal of Materials Chemistry. 12: 2957–2960 (2002).
* Katime I, Katime O, Katime D "Los materiales inteligentes de este Milenio: los hidrogeles polímeros". Editorial de la Universidad del País Vasco, Bilbao 2004. ISBN 84-8373-637-3.
* Katime I, Katime O y Katime D."Introducción a la Ciencia de los materiales polímeros: Síntesis y caracterización". Servicio Editorial de la Universidad del País Vasco, Bilbao 2010. ISBN 978-84-9860-356-9 | 0 | Theoretical and Fundamental Chemistry |
Fissile materials emit neutrons. Some nuclear materials, such as the weapons usable plutonium-239, emit large quantities of neutrons, making neutron detection a useful tool to search for such contraband. Radiation Portal Monitors often use Helium-3 based detectors to search for neutron signatures. However, a global supply shortage of He-3 has led to the search for other technologies for neutron detection. | 0 | Theoretical and Fundamental Chemistry |
For cellular organisms, the transport of specific molecules across compartmentalizing membrane barriers is essential in order to exchange content with their environment and with other individuals. For example, content exchange between individuals enables the exchange of genes between individuals (horizontal gene transfer), an important factor in the evolution of cellular life. While modern cells can rely on complicated protein machineries to catalyze these crucial processes, protocells must have accomplished this using more simple mechanisms.
Protocells composed of fatty acids would have been able to easily exchange small molecules and ions with their environment. Modern phospholipid bilayer cell membranes exhibit low permeability, but contain complex molecular assemblies which both actively and passively transport relevant molecules across the membrane in a highly specific manner. In the absence of these complex assemblies, simple fatty acid based protocell membranes would be more permeable and allow for greater non-specific transport across membranes. Molecules that would be highly permeable across protocell membranes include nucleoside monophosphate (NMP), nucleoside diphosphate (NDP), and nucleoside triphosphate (NTP), and may withstand millimolar concentrations of Mg. Osmotic pressure can also play a significant role regarding this passive membrane transport.
Environmental effects have been suggested to trigger conditions under which a transport of larger molecules, such as DNA and RNA, across the membranes of protocells is possible. For example, it has been proposed that electroporation resulting from lightning strikes could enable such transport. Electroporation is the rapid increase in bilayer permeability induced by the application of a large artificial electric field across the membrane. During electroporation, the lipid molecules in the membrane shift position, opening up a pore (hole) that acts as a conductive pathway through which hydrophobic molecules like nucleic acids can pass the lipid bilayer. A similar transfer of content across protocells and with the surrounding solution can be caused by freezing and subsequent thawing. This could, for instance, occur in an environment in which day and night cycles cause recurrent freezing. Laboratory experiments have shown that such conditions allow an exchange of genetic information between populations of protocells. This can be explained by the fact that membranes are highly permeable at temperatures slightly below their phase transition temperature. If this point is reached during the freeze-thaw cycle, even large and highly charged molecules can temporarily pass the protocell membrane.
Some molecules or particles are too large or too hydrophilic to pass through a lipid bilayer even under these conditions, but can be moved across the membrane through fusion or budding of vesicles, events which have also been observed for freeze-thaw cycles. This may eventually have led to mechanisms that facilitate movement of molecules to the inside of the protocell (endocytosis) or to release its contents into the extracellular space (exocytosis). | 0 | Theoretical and Fundamental Chemistry |
As described above, lecithin is highly processed. Therefore, genetically modified (GM) protein or DNA from the original GM crop from which it is derived often is undetectable – in other words, it is not substantially different from lecithin derived from non-GM crops. Nonetheless, consumer concerns about genetically modified food have extended to highly purified derivatives from GM food, such as lecithin. This concern led to policy and regulatory changes in the EU in 2000, when Commission Regulation (EC) 50/2000 was passed which required labelling of food containing additives derived from GMOs, including lecithin. Because it is nearly impossible to detect the origin of derivatives such as lecithin, the European regulations require those who wish to sell lecithin in Europe to use a meticulous, but essential system of identity preservation (IP). | 0 | Theoretical and Fundamental Chemistry |
Tholins were detected on the dwarf planet Ceres by the Dawn mission. Most of the planet's surface is extremely rich in carbon, with approximately 20% carbon by mass in its near surface. The carbon content is more than five times higher than in carbonaceous chondrite meteorites analyzed on Earth. | 0 | Theoretical and Fundamental Chemistry |
More typically for laboratory operations, the Prilezhaev reaction is employed. This approach involves the oxidation of the alkene with a peroxyacid such as mCPBA. Illustrative is the epoxidation of styrene with perbenzoic acid to styrene oxide:
The reaction proceeds via what is commonly known as the "Butterfly Mechanism". The peroxide is viewed as an electrophile, and the alkene a nucleophile. The reaction is considered to be concerted. The butterfly mechanism allows ideal positioning of the sigma star orbital for π electrons to attack. Because two bonds are broken and formed to the epoxide oxygen, this is formally an example of a coarctate transition state.
Hydroperoxides are also employed in catalytic enantioselective epoxidations, such as the Sharpless epoxidation and the Jacobsen epoxidation. Together with the Shi epoxidation, these reactions are useful for the enantioselective synthesis of chiral epoxides. Oxaziridine reagents may also be used to generate epoxides from alkenes. | 0 | Theoretical and Fundamental Chemistry |
In vibrational spectroscopy, transitions are observed between different vibrational states. In a fundamental vibration, the molecule is excited from its ground state (v = 0) to the first excited state (v = 1). The symmetry of the ground-state wave function is the same as that of the molecule. It is, therefore, a basis for the totally symmetric representation in the point group of the molecule. It follows that, for a vibrational transition to be allowed, the symmetry of the excited state wave function must be the same as the symmetry of the transition moment operator.
In infrared spectroscopy, the transition moment operator transforms as either x and/or y and/or z. The excited state wave function must also transform as at least one of these vectors. In Raman spectroscopy, the operator transforms as one of the second-order terms in the right-most column of the character table, below.
The molecule methane, CH, may be used as an example to illustrate the application of these principles. The molecule is tetrahedral and has T symmetry. The vibrations of methane span the representations A + E + 2T. Examination of the character table shows that all four vibrations are Raman-active, but only the T vibrations can be seen in the infrared spectrum.
In the harmonic approximation, it can be shown that overtones are forbidden in both infrared and Raman spectra. However, when anharmonicity is taken into account, the transitions are weakly allowed.
In Raman and infrared spectroscopy, the selection rules predict certain vibrational modes to have zero intensities in the Raman and/or the IR. Displacements from the ideal structure can result in relaxation of the selection rules and appearance of these unexpected phonon modes in the spectra. Therefore, the appearance of new modes in the spectra can be a useful indicator of symmetry breakdown. | 0 | Theoretical and Fundamental Chemistry |
Several advantages in both spatial resolution and minimizing photodamage/photobleaching in organic and/or biological samples are obtained by two-photon or three-photon excitation FCS. | 0 | Theoretical and Fundamental Chemistry |
TAL effectors are proteins that are secreted by Xanthomonas bacteria via their type III secretion system when they infect plants. The DNA binding domain contains a repeated highly conserved 33–34 amino acid sequence with divergent 12th and 13th amino acids. These two positions, referred to as the Repeat Variable Diresidue (RVD), are highly variable and show a strong correlation with specific nucleotide recognition. This straightforward relationship between amino acid sequence and DNA recognition has allowed for the engineering of specific DNA-binding domains by selecting a combination of repeat segments containing the appropriate RVDs. Notably, slight changes in the RVD and the incorporation of "nonconventional" RVD sequences can improve targeting specificity. | 1 | Applied and Interdisciplinary Chemistry |
Calcium deficiency symptoms appear initially as localized tissue necrosis leading to stunted plant growth, necrotic leaf margins on young leaves or curling of the leaves, and eventual death of terminal buds and root tips. Generally, the new growth and rapidly growing tissues of the plant are affected first. The mature leaves are rarely if ever affected because calcium accumulates to high concentrations in older leaves. Calcium deficiencies in plants are associated with reduced height, fewer nodes, and less leaf area.
Crop-specific symptoms include:
; Apple : Bitter pit – fruit skins develop pits, brown spots appear on skin and/or in flesh and taste of those areas is bitter. This usually occurs when fruit is in storage, and Bramley apples are particularly susceptible. Related to boron deficiency, "water cored" apples seldom display bitter pit effects.
; Cabbage, lettuce and brussels sprouts :There is some evidence that plants like lettuce are more likely to experience tipburn (burned edges of leaves) if they're experiencing a deficiency of calcium.
; Carrot : Cavity spot – oval spots develop into craters which may be invaded by other disease-causing organisms.
; Celery : Stunted growth, central leaves stunted.
; Tomatoes and peppers:Blossom end rot – Symptoms start as sunken, dry decaying areas at the blossom end of the fruit, furthest away from the stem, not all fruit on a truss is necessarily affected. Sometimes rapid growth from high-nitrogen fertilizers may exacerbate blossom end rot. Water management and preventing water stress is key to minimizing its occurrence.:Although it was once common knowledge that blossom end rot was caused by calcium deficiencies, there are also other proposed causes. | 1 | Applied and Interdisciplinary Chemistry |
Prior to 1907, nearly all the copper mined in the US came from underground vein deposits, averaging 2.5 percent copper. By 1991, the average grade of copper ore mined in the US had fallen to only 0.6 percent. | 1 | Applied and Interdisciplinary Chemistry |
Colored dissolved organic matter (CDOM) absorbs light, making the water appear darker or tea-colored. Absorption by CDOM is one measure of water clarity. Clarity can still be quite high in terms of visibility with high amounts of CDOM in the water, but the color of the water will be altered to yellow or brown, and the water will appear darker than water with low CDOM concentrations. CDOM absorbs blue light more strongly than other colors, shifting the color of the water toward the yellow and red part of the visible light spectrum as the water gets darker. For example, in lakes with high CDOM concentrations, the bottom of the lake may be clearly visible to the human eye, but a white surface in the same lake water may appear yellow or brown. | 0 | Theoretical and Fundamental Chemistry |
The a-keto stabilized ylides derived from bisphosphines like dppe, dppm, etc., viz., [PhPCHPPh]C(H)C(O)R and [PhPCHCHPPh]C(H)C(O)R (R = Me, Ph or OMe) constitute an important class of hybrid ligands containing both phosphine and ylide functionalities, and can exist in ylidic and enolate forms. These ligands can therefore be engaged in different kinds of bonding with metal ions like palladium and platinum. | 0 | Theoretical and Fundamental Chemistry |
Around 90% of the production is used to make the pigment titanium dioxide (). The conversion involves hydrolysis of , a process that forms hydrogen chloride:
In some cases, is oxidised directly with oxygen: | 0 | Theoretical and Fundamental Chemistry |
Surface science is the study of physical and chemical phenomena that occur at the interface of two phases, including solid–liquid interfaces, solid–gas interfaces, solid–vacuum interfaces, and liquid–gas interfaces. It includes the fields of surface chemistry and surface physics. Some related practical applications are classed as surface engineering. The science encompasses concepts such as heterogeneous catalysis, semiconductor device fabrication, fuel cells, self-assembled monolayers, and adhesives. Surface science is closely related to interface and colloid science. Interfacial chemistry and physics are common subjects for both. The methods are different. In addition, interface and colloid science studies macroscopic phenomena that occur in heterogeneous systems due to peculiarities of interfaces. | 0 | Theoretical and Fundamental Chemistry |
MIKES, as the name implies, is used for kinetic energy spectrometery. This means that certain criteria are needed to accomplish this. One such feature of MIKES is that it has high kinetic energy resolution and good angular resolution. This is due to the fact that MIKES has low accelerating voltage, around 3 kilo-volts. Another feature is that it has good differential pumping between the various regions of the instrument. In addition, MIKES has multiple systems for bringing in and/or overseeing collision gases or vapors and the ability to vary slit height and width. This prevents favoritism when determining kinetic energy distributions. Although common now, back in the 1970s, MIKES had a great computer compatibility that allowed for readily obtainable molecular structures. | 0 | Theoretical and Fundamental Chemistry |
The parent hydride compound is the hypothetical molecule PH.
Pentaphenylphosphorane (PhP) is stable.
Pentaalkoxyphosphoranes are more common with electronegative substituents. Examples of P(OR) (R = alkyl), have however been prepared by reaction of phosphites with benzene alkyl sulfenates: | 0 | Theoretical and Fundamental Chemistry |
Bainite is a plate-like microstructure that forms in steels at temperatures of 125–550 °C (depending on alloy content). First described by E. S. Davenport and Edgar Bain, it is one of the products that may form when austenite (the face-centered cubic crystal structure of iron) is cooled past a temperature where it is no longer thermodynamically stable with respect to ferrite, cementite, or ferrite and cementite. Davenport and Bain originally described the microstructure as being similar in appearance to tempered martensite.
A fine non-lamellar structure, bainite commonly consists of cementite and dislocation-rich ferrite. The large density of dislocations in the ferrite present in bainite, and the fine size of the bainite platelets, makes this ferrite harder than it normally would be.
The temperature range for transformation of austenite to bainite (125–550 °C) is between those for pearlite and martensite. In fact, there is no fundamental lower limit to the bainite-start temperature. When formed during continuous cooling, the cooling rate to form bainite is more rapid than that required to form pearlite, but less rapid than is required to form martensite (in steels of the same composition). Most alloying elements will retard the formation of bainite, though carbon is the most effective in doing so. Aluminium or cobalt are exceptions in that they can accelerate the decomposition of austenite and raise the transformation temperature.
The microstructures of martensite and bainite at first seem quite similar, consisting of thin plates which in low-alloy steels cluster together. This is a consequence of the two microstructures sharing many aspects of their transformation mechanisms. However, morphological differences do exist that require a transmission electron microscope to see. Under a light microscope, the microstructure of bainite appears darker than untempered martensite because the bainite has more substructure.
The hardness of bainite can be between that of pearlite and untempered martensite in the same steel hardness. The fact that it can be produced during both isothermal or continuous cooling is a big advantage, because this facilitates the production of large components without excessive additions of alloying elements. Unlike martensitic steels, alloys based on bainite often do not need further heat treatment after transformation in order to optimise strength and toughness. | 1 | Applied and Interdisciplinary Chemistry |
Tropical cyclone engineering, or hurricane engineering, is a specialist sub-discipline of civil engineering that encompasses planning, analysis, design, response, and recovery of civil engineering systems and infrastructure for hurricane hazards. Hurricane engineering is a relatively new and emerging discipline within the field of civil engineering. It is an integration of many recognized branches of engineering, such as structural engineering, wind engineering, coastal engineering, and forensic engineering, with other recognized sciences and planning functions such as, climatology, oceanography, architecture, emergency management and preparedness, hazard mitigation, and hazard vulnerability analysis. Hurricane engineering aims to minimize risks to human safety, the natural and built environment, and business processes. | 1 | Applied and Interdisciplinary Chemistry |
The key reaction in the Vollhardt synthesis (2000, racemic) was an alkyne trimerisation of tryptamine derivative 1 with acetylene and organocobalt compound CpCo(CH) (THF, 0 °C) to tricycle 2 after deprotection of the amine group (KOH, MeOH/HO reflux). Subsequent reaction with iron nitrate brought about a [1,8]-conjugate addition to tetracycle 3, amine alkylation with (Z)-1-bromo-4-[(tert-butyldimethylsilyl)oxy]-2-iodobut-2-ene (see Rawal synthesis) and lithium carbonate, and isomerization of the diene system (NaOiPr, iPrOH) formed enone 4. A Heck reaction as in the Rawal synthesis (palladium acetate / triphenylphosphine), accompanied by aromatization formed pyridone 5 and lithium aluminium hydride reduction and TBS group deprotection formed isostrychnine 6. | 0 | Theoretical and Fundamental Chemistry |
Subcutaneous implants of levonorgestrel have been marketed as birth control implants under the brand names Norplant and Jadelle and are available for use in some countries. | 0 | Theoretical and Fundamental Chemistry |
Polyamorphism has been experimentally observed or theoretically suggested in silicon, liquid phosphorus, triphenyl phosphate, mannitol, and in some other molecular network-forming substances. | 0 | Theoretical and Fundamental Chemistry |
There are two different settings for the one-million-dollar-prize Navier–Stokes existence and smoothness problem. The original problem is in the whole space , which needs extra conditions on the growth behavior of the initial condition and the solutions. In order to rule out the problems at infinity, the Navier–Stokes equations can be set in a periodic framework, which implies that they are no longer working on the whole space but in the 3-dimensional torus . Each case will be treated separately. | 1 | Applied and Interdisciplinary Chemistry |
Tollens' reagent is also used to apply a silver mirror to glassware; for example the inside of an insulated vacuum flask. The underlying chemical process is called silver mirror reaction. The reducing agent is glucose (an aldehyde) for such applications. Clean glassware is required for a high quality mirror. To increase the speed of deposition, the glass surface may be pre-treated with tin(II) chloride stabilised in hydrochloric acid solution.
For applications requiring the highest optical quality, such as in telescope mirrors, the use of tin(II) chloride is problematic, since it creates nanoscale roughness and reduces the reflectivity.
Methods to produce telescope mirrors include additional additives to increase adhesion and film resilience, such as in Martin's method, which includes tartaric acid and ethanol. | 0 | Theoretical and Fundamental Chemistry |
The cyanate ion is an anion with the chemical formula . It is a resonance of three forms: (61%) ↔ (30%) ↔ (4%).
Cyanate is the derived anion of isocyanic acid, H−N=C=O, and its lesser tautomer cyanic acid (a.k.a. cyanol), H−O−C≡N.
Any salt containing the ion, such as ammonium cyanate, is called a cyanate.
The cyanate ion is an isomer of the much-less-stable fulminate anion, or .
The cyanate ion is an ambidentate ligand, forming complexes with a metal ion in which either the nitrogen or oxygen atom may be the electron-pair donor. It can also act as a bridging ligand.
Compounds that contain the cyanate functional group, −O−C≡N, are known as cyanates or cyanate esters. The cyanate functional group is distinct from the isocyanate functional group, −N=C=O; the fulminate functional group, ; and the nitrile oxide functional group, or . | 0 | Theoretical and Fundamental Chemistry |
Although white phosphorus converts to the thermodynamically more stable red allotrope, the formation of the cubic- molecule is not observed in the condensed phase. Analogs of this hypothetical molecule have been prepared from phosphaalkynes. White phosphorus in the gaseous state and as waxy solid consists of reactive molecules. | 0 | Theoretical and Fundamental Chemistry |
Aflatoxin total synthesis concerns the total synthesis of a group of organic compounds called aflatoxins. These compounds occur naturally in several fungi. As with other chemical compound targets in organic chemistry, the organic synthesis of aflatoxins serves various purposes. Traditionally it served to prove the structure of a complex biocompound in addition to evidence obtained from spectroscopy. It also demonstrates new concepts in organic chemistry (reagents, reaction types) and opens the way to molecular derivatives not found in nature. And for practical purposes, a synthetic biocompound is a commercial alternative to isolating the compound from natural resources. Aflatoxins in particular add another dimension because it is suspected that they have been mass-produced in the past from biological sources as part of a biological weapons program.
The synthesis of racemic aflatoxin B1 has been reported by Buechi et al. in 1967 and that of racemic aflatoxin B2 by Roberts et al. in 1968 The group of Barry Trost of Stanford University is responsible for the enantioselective total synthesis of (+)-Aflatoxin B and B in 2003. In 2005 the group of E. J. Corey of Harvard University presented the enantioselective synthesis of Aflatoxin B. | 0 | Theoretical and Fundamental Chemistry |
* Kuipers graduated in 1986 in biology at Utrecht University.
* In 1988 Kuipers obtained an EMBO Fellowship for three month at the lab of Dr. J. Gallay of the University of Paris-Sud in Orsay (Paris) to study time-resolved Fluorescence.
* In 1989 Kuipers received a SHELL fellowship to give lectures in the United States at Prof. Mahendra Jain (Newark), Prof. Michael Gelb (Seattle) and Prof. Yang (San Francisco) and on a conference about Time Resolved Fluorescence.
* In 1990 Kuipers obtained his doctorate at the University of Utrecht in biochemistry with the thesis Probing the mechanism of pancreatic phospholipase A2 by protein engineering.
* From 1990 to 1997 he worked as a project leader on molecular genetics at the Department of Biophysical Chemistry of NIZO food research, a contract research center in Ede (The Netherlands).
* From 1997 to 1999 he was head of genetics and research leader of the section Microbial Ingredients of the same institute.
* From 1999 Kuipers is professor and head of the ‘Molecular Genetics of Prokaryotes’ group of the Groningen Biomolecular Sciences and Biotechnology Institute (GBB) of the University of Groningen. | 0 | Theoretical and Fundamental Chemistry |
The Mount Polley Mining Corporation has invested more than $70 million into remediation efforts since the dam breach in 2014. No government funding has been spent on the clean-up or repair work at the site. The restoration and remediation strategy was carried out in four stages: impact reduction, post-breach environmental assessment, long-term health and environmental assessment, and implementation of work focused on remediation to prevent environmental and health impacts and to improve the condition of the areas affected by breach. | 1 | Applied and Interdisciplinary Chemistry |
;Spatial resolution
The spatial resolution of an AFM-IR instrument is related to the contact area between the probe and sample. The contact area is given by a = 3PR/4E* and 1/E* = (1-n)/ E+ (1-n)/ E, where P is the force employed to the probe, n and nrepresent the Poisson ratios of the sample and probe, respectively, and E and E are the elastic moduli of the sample and probe materials respectively. Typically, an AFM-IR has a lateral spatial resolution of 10–400 nm, for example, 100 nm, λ/150, and λ/400. Recently, Ruggeri et al. have demonstrated the acquisition of infrared absorption spectra and chemical maps at the single molecule level in the case of protein molecules with ca. 10 nm diameter and a molecular weight of 400 kDa.
;Instrumentation
In AFM-IR, an AFM probe is used to measure the absorption response of the sample to infrared radiation. The general approach for AFM/FTIR is shown in Figure 10.
There are a few different experimental setups when the infrared radiation is projected onto the sample as shown below: top, side, and bottom illumination setups (Figure 11).
In the first developed setup of AFM-IR, a sample is mounted onto an infrared-transparent zinc selenide prism for excitation purposes (Figure 12), then an optical parametric oscillator (OPO)-based tunable IR lased is radiated on the molecules to be probed by the instrument. Similar to conventional ATR spectroscopy, IR beam illuminates the sample through total internal reflection mechanism (Figure 12). The sample will heat up while absorbing radiation which causes a rapid thermal expansion of the sample surface. This expansion will increase the resonant oscillations of the AFM cantilever in a characteristic ringdown pattern (ringdown patterns means the decay of cantilever oscillation exponential in nature). Through Fourier transformation analysis, the signal could be isolated to obtain the amplitudes and frequencies of the oscillations. The amplitudes of the cantilever provide information of local absorption spectra, whereas the oscillation frequencies depend on the mechanical stiffness of the sample (Figure 12). | 0 | Theoretical and Fundamental Chemistry |
Arsenical bronze is an alloy in which arsenic, as opposed to or in addition to tin or other constituent metals, is combined with copper to make bronze. The use of arsenic with copper, either as the secondary constituent or with another component such as tin, results in a stronger final product and better casting behavior.
Copper ore is often naturally contaminated with arsenic; hence, the term "arsenical bronze" when used in archaeology is typically only applied to alloys with an arsenic content higher than 1% by weight, in order to distinguish it from potentially accidental additions of arsenic. | 1 | Applied and Interdisciplinary Chemistry |
The legal limits for tritium in drinking water vary widely from country to country. Some figures are given below:
The American limit results in a dose of 4.0 millirems (or 40 microsieverts in SI units) per year per EPA regulation 40CFR141, and is based on outdated dose calculation standards of National Bureau of Standards Handbook 69 circa 1963. Four millirem per year is about 1.3% of the natural background radiation (roughly 3,000 μSv). For comparison, the banana equivalent dose (BED) is set at 0.1 μSv, so the statutory limit in the US is set at 400 BED. Updated dose calculation standards based on International Commission on Radiological Protection Report 30 and used in the NRC Regulation 10CFR20 results in a dose of 0.9 millirem (9 μSv) per year at 740 Bq/liter (20,000 pCi/liter). | 0 | Theoretical and Fundamental Chemistry |
Freeze-casting is a directional solidification technique that is utilized to fabricate materials exhibiting anisotropic, elongated pore structures. Pore morphology is defined, in large part, by the morphology of the solidified fluid.
Titanium foams exhibiting dendritic and lamellar pore structures have been produced, through the use of non-aqueous and aqueous processing respectively. These materials exhibit anisotropic mechanical properties as a result of their anisotropic pore structures. Compressive strength for loads applied parallel to the wall direction of titanium foams are found to be, on average, 2.5 times greater than for those applied perpendicular to the wall direction. | 0 | Theoretical and Fundamental Chemistry |
A DNA microarray (also commonly known as DNA chip or biochip) is a collection of microscopic DNA spots attached to a solid surface. Scientists use DNA microarrays to measure the expression levels of large numbers of genes simultaneously or to genotype multiple regions of a genome. Each DNA spot contains picomoles (10 moles) of a specific DNA sequence, known as probes (or reporters or oligos). These can be a short section of a gene or other DNA element that are used to hybridize a cDNA or cRNA (also called anti-sense RNA) sample (called target) under high-stringency conditions. Probe-target hybridization is usually detected and quantified by detection of fluorophore-, silver-, or chemiluminescence-labeled targets to determine relative abundance of nucleic acid sequences in the target. The original nucleic acid arrays were macro arrays approximately 9 cm × 12 cm and the first computerized image based analysis was published in 1981. It was invented by Patrick O. Brown. An example of its application is in SNPs arrays for polymorphisms in cardiovascular diseases, cancer, pathogens and GWAS analysis. It is also used for the identification of structural variations and the measurement of gene expression. | 1 | Applied and Interdisciplinary Chemistry |
CMF can replace rolled steel armour with the same protection for one-third the weight. It can block fragments and the shock waves that are responsible for traumatic brain injuries (TBI). CMF was tested against blasts and fragments. The panels were tested against 23 × 152 mm high explosive incendiary rounds (as in anti-aircraft weapons) that release a high-pressure blast wave and metal fragments at speeds up to 1524 m/s. The CMF panels were able to withstand the blast and frag impacts without bowing or cracking. The thicker sample (16.7 mm thick) was able to completely stop various-sized fragments from three separate incendiary ammunition tests. It was shown that CMF is able to locally arrest the fragments and dissipate the energy of the incident blast wave and impede the spread of failure, as opposed to fully solid materials that transfers the energy across the entire plate, damaging the bulk material. In this study, stainless steel CMF blocked blast pressure and fragmentation at 5,000 feet per second from high explosive incendiary (HEI) rounds that detonate at 18 inches away. Steel CMF plates (9.5 mm or 16.75 mm thick) that were placed 18 inches from the strike plate held up against the wave of blast pressure and against the copper and steel fragments created by a 23×152 mm HEI round (as in anti-aircraft weapons) as well as a 2.3mm aluminium strikeplate. The performance of the steel CMF was far better than the same weight aluminium plate against the same type of blast and fragments. | 0 | Theoretical and Fundamental Chemistry |
Perfluoroaromatic compounds contain only carbon and fluorine, like other fluorocarbons, but also contain an aromatic ring. The three most important examples are hexafluorobenzene, octafluorotoluene, and octafluoronaphthalene.
Perfluoroaromatic compounds can be manufactured via the Fowler process, like fluoroalkanes, but the conditions must be adjusted to prevent full fluorination. They can also be made by heating the corresponding perchloroaromatic compound with potassium fluoride at high temperature (typically 500 °C), during which the chlorine atoms are replaced by fluorine atoms. A third route is defluorination of the fluoroalkane; for example, octafluorotoluene can be made from perfluoromethylcyclohexane by heating to 500 °C with a nickel or iron catalyst.
Perfluoroaromatic compounds are relatively volatile for their molecular weight, with melting and boiling points similar to the corresponding aromatic compound, as the table below shows. They have high density and are non-flammable. For the most part, they are colorless liquids. Unlike the perfluoralkanes, they tend to be miscible with common solvents. | 1 | Applied and Interdisciplinary Chemistry |
The area and mass flow rate are held constant for Rayleigh flow. Unlike Fanno flow, the Fanning friction factor, f, remains constant. These relations are shown below with the * symbol representing the throat location where choking can occur.
Differential equations can also be developed and solved to describe Rayleigh flow property ratios with respect to the values at the choking location. The ratios for the pressure, density, static temperature, velocity and stagnation pressure are shown below, respectively. They are represented graphically along with the stagnation temperature ratio equation from the previous section. A stagnation property contains a 0 subscript. | 1 | Applied and Interdisciplinary Chemistry |
Disorders of fatty acid metabolism can be described in terms of, for example, hypertriglyceridemia (too high level of triglycerides), or other types of hyperlipidemia. These may be familial or acquired.
Familial types of disorders of fatty acid metabolism are generally classified as inborn errors of lipid metabolism. These disorders may be described as fatty acid oxidation disorders or as a lipid storage disorders, and are any one of several inborn errors of metabolism that result from enzyme or transport protein defects affecting the ability of the body to oxidize fatty acids in order to produce energy within muscles, liver, and other cell types. When a fatty acid oxidation disorder affects the muscles, it is a metabolic myopathy.
Moreover, cancer cells can display irregular fatty acid metabolism with regard to both fatty acid synthesis and mitochondrial fatty acid oxidation (FAO) that are involved in diverse aspects of tumorigenesis and cell growth. | 1 | Applied and Interdisciplinary Chemistry |
Metreleptin, sold under the brand name Myalept among others, is a synthetic analog of the hormone leptin used to treat various forms of dyslipidemia. It has been approved in Japan for metabolic disorders including lipodystrophy and in the United States as replacement therapy to treat the complications of leptin deficiency, in addition to diet, in patients with congenital generalized or acquired generalized lipodystrophy.
The most common side effects include hypoglycaemia (low blood glucose) and weight loss.
It was approved for medical use in Canada in January 2024. | 1 | Applied and Interdisciplinary Chemistry |
The Otto Warburg Medal is awarded annually by the German Society for Biochemistry and Molecular Biology (German: Gesellschaft für Biochemie und Molekularbiologie or GBM) to honour scientists who have contributed important work in the field of biological chemistry. It is named after Otto Warburg, a renowned German physiologist and Nobel Prize laureate. It was first awarded on his 80th birthday on 8 October 1963.
Up to 2013, nine Warburg Medal recipients have also been awarded the Nobel Prize. | 1 | Applied and Interdisciplinary Chemistry |
Petroleum geochemistry is a branch of geochemistry (the application of chemical concepts to understand geological systems) which deals specifically with petroleum and its origin, generation, and accumulation, as well as its extraction, refinement, and use. Petroleum, also known as crude oil, is a solid, liquid, and/or gaesous mix of hydrocarbons. These hydrocarbons are from the burial and metamorphosis of organic matter from millions of years ago; the organic matter is from marine animals, plants, and algae. Petroleum is extracted from the Earth (above or below its surface, depending on the geology of the formation), refined, and used as an energy source.
Crude oil is most commonly organised into four types - light, heavy, sweet, and sour. Petroleum is a non-renewable energy source (also known as a "fossil fuel"), so the efficacy of extraction and refining is important for its continued use; multiple techniques are used to detect and to extract crude oil, based on the source rock it is found in and the type of oil itself. | 0 | Theoretical and Fundamental Chemistry |
Adenosine diphosphate (ADP), also known as adenosine pyrophosphate (APP), is an important organic compound in metabolism and is essential to the flow of energy in living cells. ADP consists of three important structural components: a sugar backbone attached to adenine and two phosphate groups bonded to the 5 carbon atom of ribose. The diphosphate group of ADP is attached to the 5’ carbon of the sugar backbone, while the adenine attaches to the 1’ carbon.
ADP can be interconverted to adenosine triphosphate (ATP) and adenosine monophosphate (AMP). ATP contains one more phosphate group than does ADP. AMP contains one fewer phosphate group. Energy transfer used by all living things is a result of dephosphorylation of ATP by enzymes known as ATPases. The cleavage of a phosphate group from ATP results in the coupling of energy to metabolic reactions and a by-product of ADP. ATP is continually reformed from lower-energy species ADP and AMP. The biosynthesis of ATP is achieved throughout processes such as substrate-level phosphorylation, oxidative phosphorylation, and photophosphorylation, all of which facilitate the addition of a phosphate group to ADP. | 1 | Applied and Interdisciplinary Chemistry |
BIND contains information on three types of data: interactions, molecular complexes and pathways.
# Interactions are the basic component of BIND and describe how 2 or more objects (A and B) interact with each other. The objects can be a variety of things: DNA, RNA, genes, proteins, ligands, or photons. The interaction entry contains the most information about a molecule; it provides information on its name and synonyms, where it is found (e.g. where in the cell, what species, when it is active, etc.), and its sequence or where its sequence can be found. The interaction entry also outlines the experimental conditions required to observe binding in vitro, chemical dynamics (including thermodynamics and kinetics).
# The second type of BIND entries are the molecular complexes. Molecular complexes are defined as an aggregate of molecules that are stable and have a function when bound to each other. The record may also contain some information on the role of the complex in various interactions and the molecular complex entry links data from 2 or more interaction records.
# The third component of BIND is the pathway record section. A pathway consists of a network of interactions that are involved in the regulation of cellular processes. This section may also contain information on phenotypes and diseases related to the pathway.
<br />The minimum amount of information needed to create an entry in BIND is a PubMed publication reference and an entry in another database (e.g. GenBank). Each entry within the database provides references/authors for the data. As BIND is a constantly growing database, all components of BIND track updates and changes.
BIND is based on a data specification written using Abstract Syntax Notation 1 (ASN.1) language. ASN.1 is used also by NCBI when storing data for their Entrez system and because of this BIND uses the same standards as NCBI for data representation. The ASN.1 language is preferred because it can be easily translated into other data specification languages (e.g. XML), can easily handle complex data and can be applied to all biological interactions – not just proteins. Bader and Hogue (2000) have prepared a detailed manuscript on the ASN.1 data specification used by BIND. | 1 | Applied and Interdisciplinary Chemistry |
In fluid mechanics, the Okubo–Weiss parameter, (normally given by "W") is a measure of the relative importance of deformation and rotation at a given point. It is calculated as the sum of the squares of normal and shear strain minus the relative vorticity. This is widely applicable in fluid properties particularly in identifying and describing oceanic eddies.
For a horizontally non-divergent flow in the ocean, the parameter is given by:
where:
* is the normal strain.
* is the shear strain.
* is the relative vorticity. | 1 | Applied and Interdisciplinary Chemistry |
The concepts of total pressure and dynamic pressure arise from Bernoulli's equation and are significant in the study of all fluid flows. (These two pressures are not pressures in the usual sense—they cannot be measured using an aneroid, Bourdon tube or mercury column.) To avoid potential ambiguity when referring to pressure in fluid dynamics, many authors use the term static pressure to distinguish it from total pressure and dynamic pressure. Static pressure is identical to pressure and can be identified for every point in a fluid flow field.
A point in a fluid flow where the flow has come to rest (that is to say, speed is equal to zero adjacent to some solid body immersed in the fluid flow) is of special significance. It is of such importance that it is given a special name—a stagnation point. The static pressure at the stagnation point is of special significance and is given its own name—stagnation pressure. In incompressible flows, the stagnation pressure at a stagnation point is equal to the total pressure throughout the flow field. | 1 | Applied and Interdisciplinary Chemistry |
C. albicans is a fungal pathogen of humans and is responsible for hospital-acquired bloodstream infections. MLST technique has used to characterize C. albicans isolates. Combination of the alleles at the different loci results in unique diploid sequence types that can be used to discriminate strains. MLST has been shown successfully applied to study the epidemiology of C. albicans in the hospital as well as the diversity of C. albicans isolates obtained from diverse ecological niches including human and animal hosts. | 1 | Applied and Interdisciplinary Chemistry |
The institute has set up a Centre for Skill Development, offering certificate courses in the areas of environmental impact and water quality assessment. Prof. V. Rajagopalan (1993 Vice President of the World Bank) had in his time (1955–65) with the Institute created a national programme for water industry professionals. Graduate programmes were established in Public Health Engineering at the Guindy Engineering College, Madras, Roorkee Engineering University ,and VJTI in Mumbai. | 1 | Applied and Interdisciplinary Chemistry |
Tuck-in complexes retain nucleophilicity at the methylene carbon. They can be activated by Lewis acids to generate active catalysts for use in Ziegler–Natta catalysis. The Lewis acid attaches to the CH group, exposing a vacant site on the electrophilic Zr(IV) centre. | 0 | Theoretical and Fundamental Chemistry |
The difference between the two heating values depends on the chemical composition of the fuel. In the case of pure carbon or carbon monoxide, the two heating values are almost identical, the difference being the sensible heat content of carbon dioxide between 150 °C and 25 °C (sensible heat exchange causes a change of temperature, while latent heat is added or subtracted for phase transitions at constant temperature. Examples: heat of vaporization or heat of fusion). For hydrogen, the difference is much more significant as it includes the sensible heat of water vapor between 150 °C and 100 °C, the latent heat of condensation at 100 °C, and the sensible heat of the condensed water between 100 °C and 25 °C. All in all, the higher heating value of hydrogen is 18.2% above its lower heating value (142MJ/kg vs. 120MJ/kg). For hydrocarbons, the difference depends on the hydrogen content of the fuel. For gasoline and diesel the higher heating value exceeds the lower heating value by about 10% and 7%, respectively, and for natural gas about 11%.
A common method of relating HHV to LHV is:
where H is the heat of vaporization of water, n is the number of moles of water vaporized and n is the number of moles of fuel combusted.
* Most applications that burn fuel produce water vapor, which is unused and thus wastes its heat content. In such applications, the lower heating value must be used to give a benchmark for the process.
* However, for true energy calculations in some specific cases, the higher heating value is correct. This is particularly relevant for natural gas, whose high hydrogen content produces much water, when it is burned in condensing boilers and power plants with flue-gas condensation that condense the water vapor produced by combustion, recovering heat which would otherwise be wasted. | 0 | Theoretical and Fundamental Chemistry |
Intermolecular forces observed between atoms and molecules can be described phenomenologically as occurring between permanent and instantaneous dipoles, as outlined above. Alternatively, one may seek a fundamental, unifying theory that is able to explain the various types of interactions such as hydrogen bonding, van der Waals force and dipole–dipole interactions. Typically, this is done by applying the ideas of quantum mechanics to molecules, and Rayleigh–Schrödinger perturbation theory has been especially effective in this regard. When applied to existing quantum chemistry methods, such a quantum mechanical explanation of intermolecular interactions provides an array of approximate methods that can be used to analyze intermolecular interactions. One of the most helpful methods to visualize this kind of intermolecular interactions, that we can find in quantum chemistry, is the non-covalent interaction index, which is based on the electron density of the system. London dispersion forces play a big role with this.
Concerning electron density topology, recent methods based on electron density gradient methods have emerged recently, notably with the development of IBSI (Intrinsic Bond Strength Index), relying on the IGM (Independent Gradient Model) methodology. | 0 | Theoretical and Fundamental Chemistry |
The utilization of UVGI for air disinfection began in earnest in the mid-1930s. William F. Wells demonstrated in 1935 that airborne infectious organisms, specifically aerosolized B. coli exposed to 254 nm UV, could be rapidly inactivated. This built upon earlier theories of infectious droplet nuclei transmission put forth by Carl Flüugge and Wells himself. Prior to this, UV radiation had been studied predominantly in the context of liquid or solid media, rather than airborne microbes.
Shortly after Wells' initial experiments, high-intensity UVGI was employed to disinfect a hospital operating room at Duke University in 1936. The method proved a success, reducing postoperative wound infections from 11.62% without the use of UVGI to 0.24% with the use of UVGI. Soon, this approach was extended to other hospitals and infant wards using UVGI "light curtains", designed to prevent respiratory cross-infections, with noticeable success.
Adjustments in the application of UVGI saw a shift from "light curtains" to upper-room UVGI, confining germicidal irradiation above human head level. Despite its dependency on good vertical air movement, this approach yielded favorable outcomes in preventing cross-infections. This was exemplified by Wells' successful usage of upper-room UVGI between 1937 and 1941 to curtail the spread of measles in suburban Philadelphia day schools. His study found that 53.6% of susceptibles in schools without UVGI became infected, while only 13.3% of susceptibles in schools with UVGI were infected.
Richard L. Riley, initially a student of Wells, continued the study of airborne infection and UVGI throughout the 1950s and 60s, conducting significant experiments in a Veterans Hospital TB ward. Riley successfully demonstrated that UVGI could efficiently inactivate airborne pathogens and prevent the spread of tuberculosis.
Despite initial successes, the use of UVGI declined in the second half of the 20th century era due to various factors, including a rise in alternative infection control and prevention methods, inconsistent efficacy results, and concerns regarding its safety and maintenance requirements. However, recent events like a rise in multiple drug-resistant bacteria and the COVID-19 pandemic have renewed interest in UVGI for air disinfection. | 0 | Theoretical and Fundamental Chemistry |
In bacteria, three rescue mechanisms are known.
* The main, universal system involves transfer-messenger RNA (tmRNA) and SmpB. The tRNA first binds to the ribosome like a tRNA, then with SmpB's help shifts into the mRNA position to translate a short peptide ending on a normal stop codon.
* Alternative ribosome-rescue factor A (ArfA) is an alternative system in E. coli. It recruits RF2.
* Alternative ribosome-rescue factor B (ArfB) is another alternative from E. coli. It works like a GGQ-release factor itself, releasing the peptide from tRNA. At the same time, it fits into the mRNA tunnel to remove the mRNA.
In eukaryotes, the main mechanism involves PELO:HBS1L. | 1 | Applied and Interdisciplinary Chemistry |
In organic chemistry, an aminomethyl group is a monovalent functional group with formula . It can be described as a methyl group substituted by an amino group . | 0 | Theoretical and Fundamental Chemistry |
Particle deposition is the spontaneous attachment of particles to surfaces. The particles in question are normally colloidal particles, while the surfaces involved may be planar, curved, or may represent particles much larger in size than the depositing ones (e.g., sand grains). Deposition processes may be triggered by appropriate hydrodynamic flow conditions and favorable particle-surface interactions. Depositing particles may just form a monolayer which further inhibits additional particle deposition, and thereby one refers to surface blocking. Initially attached particles may also serve as seeds for further particle deposition, which leads to the formation of thicker particle deposits, and this process is termed as surface ripening or fouling. While deposition processes are normally irreversible, initially deposited particles may also detach. The latter process is known as particle release and is often triggered by the addition of appropriate chemicals or a modification in flow conditions.
Microorganisms may deposit to surfaces in a similar fashion as colloidal particles. When macromolecules, such as proteins, polymers or polyelectrolytes attach to surfaces, one rather calls this process adsorption. While adsorption of macromolecules largely resembles particle deposition, macromolecules may substantially deform during adsorption. The present article mainly deals with particle deposition from liquids, but similar process occurs when aerosols or dust deposit from the gas phase. | 0 | Theoretical and Fundamental Chemistry |
Subsets and Splits
No community queries yet
The top public SQL queries from the community will appear here once available.