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Neuroproteomics has the difficult task of defining on a molecular level the pathways of consciousness, senses, and self. Neurological disorders are unique in that they do not always exhibit outward symptoms. Defining the disorders becomes difficult and so neuroproteomics is a step in the right direction of identifying bio-markers that can be used to detect diseases. Not only does the field have to map out the different proteins possible from the genome, but there are many modifications that happen after transcription that affect function as well. Because neurons are such dynamic structures, changing with every action potential that travels through them, neuroproteomics offers the most potential for mapping out the molecular template of their function. Genomics offers a static roadmap of the cell, while proteomics can offer a glimpse into structures smaller than the cell because of its specific nature to each moment in time. | 1 | Applied and Interdisciplinary Chemistry |
*Wang, W., Germanenko, I., & El-Shall, M. S. (2002). Room-temperature synthesis and characterization of nanocrystalline CdS, ZnS, and Cd x Zn1-x S. Chemistry of Materials, 14(7), 3028–3033.
*Panda, A. B., Glaspell, G., & El-Shall, M. S. (2006). Microwave synthesis of highly aligned ultra narrow semiconductor rods and wires. Journal of the American Chemical Society, 128(9), 2790–2791.
*Hassan, H. M., Abdelsayed, V., Abd El Rahman, S. K., AbouZeid, K. M., Terner, J., El-Shall, M. S., Al-Resayes, S. I. & El-Azhary, A. A. (2009). Microwave synthesis of graphene sheets supporting metal nanocrystals in aqueous and organic media. Journal of Materials Chemistry, 19(23), 3832–3837.
*Abdelsayed, V., Moussa, S., Hassan, H. M., Aluri, H. S., Collinson, M. M., & El-Shall, M. S. (2010). Photothermal deoxygenation of graphite oxide with laser excitation in solution and graphene-aided increase in water temperature. The Journal of Physical Chemistry Letters, 1(19), 2804–2809.
*Siamaki, A. R., Abd El Rahman, S. K., Abdelsayed, V., El-Shall, M. S., & Gupton, B. F. (2011). Microwave-assisted synthesis of palladium nanoparticles supported on graphene: A highly active and recyclable catalyst for carbon–carbon cross-coupling reactions. Journal of Catalysis, 279(1), 1–11. | 0 | Theoretical and Fundamental Chemistry |
SERS-based immunoassays can be used for detection of low-abundance biomarkers. For example, antibodies and gold particles can be used to quantify proteins in serum with high sensitivity and specificity. | 0 | Theoretical and Fundamental Chemistry |
mRNA processing acts as a form of post-transcriptional regulation, which mostly happens in eukaryotes. 3′ cleavage/polyadenylation and 5’ capping increase overall RNA stability, and the presence of 5’ cap allows ribosome binding for translation. RNA splicing allows the expression of various protein variants from the same gene.
Specific examples include:
* SR proteins
* Ribonucleoprotein
** hnRNP
** snRNP | 1 | Applied and Interdisciplinary Chemistry |
In materials with a large exciton binding energy, it is possible for a photon to have just barely enough energy to create an exciton (bound electron–hole pair), but not enough energy to separate the electron and hole (which are electrically attracted to each other). In this situation, there is a distinction between "optical band gap" and "electronic band gap" (or "transport gap"). The optical bandgap is the threshold for photons to be absorbed, while the transport gap is the threshold for creating an electron–hole pair that is not bound together. The optical bandgap is at lower energy than the transport gap.
In almost all inorganic semiconductors, such as silicon, gallium arsenide, etc., there is very little interaction between electrons and holes (very small exciton binding energy), and therefore the optical and electronic bandgap are essentially identical, and the distinction between them is ignored. However, in some systems, including organic semiconductors and single-walled carbon nanotubes, the distinction may be significant. | 0 | Theoretical and Fundamental Chemistry |
Janssen died at Meudon on 23 December 1907 and was buried at Père Lachaise Cemetery in Paris, with the name "J. Janssen" inscribed on his tomb. During his life he was made a Knight of the Legion of Honor and a Foreign Member of the Royal Society of London.
Craters on both Mars and the Moon are named in his honor. The public square in front of Meudon Observatory is named Place Jules Janssen after him. Two major prizes carry his name: the Prix Jules Janssen of the French Astronomical Society, and the Janssen Medal of the French Academy of Sciences.
Janssen named minor planet 225 Henrietta discovered by Johann Palisa, after his wife, Henrietta. | 1 | Applied and Interdisciplinary Chemistry |
Louis Nicolas Vauquelin FRS(For) HFRSE (16 May 1763 – 14 November 1829) was a French pharmacist and chemist. He was the discoverer of both chromium and beryllium. | 1 | Applied and Interdisciplinary Chemistry |
The hydrophobic effect is the observed tendency of nonpolar substances to aggregate in an aqueous solution and to be excluded by water. The word hydrophobic literally means "water-fearing", and it describes the segregation of water and nonpolar substances, which maximizes the entropy of water and minimizes the area of contact between water and nonpolar molecules. In terms of thermodynamics, the hydrophobic effect is the free energy change of water surrounding a solute. A positive free energy change of the surrounding solvent indicates hydrophobicity, whereas a negative free energy change implies hydrophilicity.
The hydrophobic effect is responsible for the separation of a mixture of oil and water into its two components. It is also responsible for effects related to biology, including: cell membrane and vesicle formation, protein folding, insertion of membrane proteins into the nonpolar lipid environment and protein-small molecule associations. Hence the hydrophobic effect is essential to life. Substances for which this effect is observed are known as hydrophobes. | 0 | Theoretical and Fundamental Chemistry |
The pyrrolidine type of DPP-4 inhibitors was first discovered after HTS. Research showed that the pyrrolidine rings were the part of the compounds that fit into the binding site. Further development has led to fluoro substituted pyrrolidines that show superior activity, as well as pyrrolidines with fused cyclopropylrings that are highly active. | 1 | Applied and Interdisciplinary Chemistry |
Because the light energy recorded by the detector array is proportional to the volume of the particles, laser diffraction results are intrinsically volume-weighted. This means that the particle size distribution represents the volume of particle material in the different size classes. This is in contrast to counting-based optical methods such as microscopy or dynamic image analysis, which report the number of particles in the different size classes. That the diffracted light is proportional to the particle’s volume also implies that results are assuming particle sphericity, i.e. that the particle size result is an equivalent spherical diameter. Hence particle shape cannot be determined by the technique.
The main graphical representation of laser diffraction results is the volume-weighted particle size distribution, either represented as density distribution (which highlights the different modes) or as cumulative undersize distribution. | 0 | Theoretical and Fundamental Chemistry |
Dissolved load can provide valuable information about the rate of soil formation and other processes of chemical erosion. In particular, the mass balance between the dissolved load and solid phase is helpful in determining surface dynamics. In addition, dissolved load can be used to reconstruct the climate of the Earth in the past. This is because chemical weathering is the major contributor to the dissolved load of a stream. The chemical weathering of silicate rocks is the primary sink for carbon dioxide in the atmosphere, because atmospheric carbon dioxide is converted into carbonate rocks in the carbonate–silicate cycle. Carbon dioxide concentrations are the primary control of the greenhouse effect, which determines the temperature of the Earth. | 0 | Theoretical and Fundamental Chemistry |
In this field, V. G. Khlopin and his colleagues and students (M. S. Merkulova, V. I. Grebenshchikov and others) developed a methodology for studying the process of isomorphous coprecipitation of microcomponents and ways to achieve equilibrium in the solid phase-solution system, - the influence of many factors on this process was established and the hypothesis of V. G. Khlopin (1924) about the subordination of the process of fractional crystallization to the law of substance distribution between two immiscible phases was proved (Khlopin's law). The possibility of using the method of isomorphic co-crystallization not only for the isolation of radioactive elements, but also for the study of their state in liquid and solid phases - for determining their valence was shown. V. G. Khlopin and A. G. Samartseva established the existence of compounds of divalent and hexavalent polonium by this method. The process of adsorption of crystalline precipitates by the surface was also studied, - the distribution between the gas phase and crystalline precipitate, as well as between the salt melt and the solid phase.
Thus, in this section, V. G. Khlopin's studies address the following key issues: <br>
1. conditions for achieving true (thermodynamic) microcomponent equilibrium between the crystalline solid phase and solution; <br>
2. the use of radioelements as indicators in determining the mechanism of isomorphic substitution of dissociated ions; <br>
3. application of general laws of isomorphous substitution for development of a method for fixation of chemical compounds present in extremely small proportions and unstable in the solid phase, establishment of their valence and chemical type, - for revealing new chemical equilibria both in the solid phase and in solution; <br>
4. conditions of adsorption equilibrium between solid crystalline phase and solution. | 0 | Theoretical and Fundamental Chemistry |
Methemoglobin is expressed as a concentration or a percentage. Percentage of methemoglobin is calculated by dividing the concentration of methemoglobin by the concentration of total hemoglobin. Percentage of methemoglobin is likely a better indicator of illness severity than overall concentration, as underlying medical conditions play an important role. For example, a methemoglobin concentration of 1.5 g/dL may represent a percentage of 10% in an otherwise healthy patient with a baseline hemoglobin of 15 mg/dL, whereas the presence of the same concentration of 1.5 g/dL of methemoglobin in an anemic patient with a baseline hemoglobin of 8 g/dL would represent a percentage of 18.75%. The former patient will be left with a functional hemoglobin concentration of 13.5 g/dL and potentially remain asymptomatic while the latter patient with a functional hemoglobin concentration 6.5 g/dL may be severely symptomatic with a methemoglobin of less than 20%.
* 1–2% Normal
* Less than 10% metHb - No symptoms
* 10–20% metHb - Skin discoloration only (most notably on mucous membranes)
* 20–30% metHb - Anxiety, headache, dyspnea on exertion
* 30–50% metHb - Fatigue, confusion, dizziness, tachypnea, palpitations
* 50–70% metHb - Coma, seizures, arrhythmias, acidosis
* Greater than 70% metHb - High risk of death
This may be further compounded by the "functional hemoglobin's" decreased ability to release oxygen in the presence of methemoglobin. Anemia, congestive heart failure, chronic obstructive pulmonary disease, and essentially any pathology that impairs the ability to deliver oxygen may worsen the symptoms of methemoglobinemia. | 1 | Applied and Interdisciplinary Chemistry |
Hydrion is a trademarked name for a popular line of compound pH indicators, marketed by Micro Essential Laboratory Inc., exhibiting a series of color changes (typically producing a recognizably different color for each pH unit) over a range of pH values. Although solutions are available, the most common forms of Hydrion are a series of papers impregnated with various mixtures of indicator dyes. It is considered a "universal indicator". | 0 | Theoretical and Fundamental Chemistry |
# Mixture of fuel and oxygen is injected into the combustion chamber.
# Powder feedstock is introduced into the chamber.
# Nitrogen gas is added between the fuel-oxygen mixture and powder feedstock in order to prevent backfiring.
# Mixture is ignited, and heated powder is ejected from the barrel onto the target material.
# Barrel is then purged by nitrogen gas ready for firing again.
# This process is repeated at a rate of between 1–10 Hz until desired thickness of coating is achieved. | 1 | Applied and Interdisciplinary Chemistry |
Phosphoenolpyruvate carboxylase (also known as PEP carboxylase, PEPCase, or PEPC; , PDB ID: 3ZGE) is an enzyme in the family of carboxy-lyases found in plants and some bacteria that catalyzes the addition of bicarbonate (HCO) to phosphoenolpyruvate (PEP) to form the four-carbon compound oxaloacetate and inorganic phosphate:
:PEP + HCO → oxaloacetate + Pi
This reaction is used for carbon fixation in CAM (crassulacean acid metabolism) and C4 carbon fixation| organisms, as well as to regulate flux through the citric acid cycle (also known as Krebs or TCA cycle) in bacteria and plants. The enzyme structure and its two step catalytic, irreversible mechanism have been well studied. PEP carboxylase is highly regulated, both by phosphorylation and allostery. | 0 | Theoretical and Fundamental Chemistry |
As of November 15, 2021, seven states in the USA declared ten cases of illnesses from an E. coli O157:H7 strain. These cases were reported from October 15, 2021 through October 27, 2021 and an investigation was carried out by the Minnesota Department of Agriculture and FDA. It was concluded that packages of spinach collected from homes of infected people were contaminated with a strain of E. coli that matched the strain causing illness. This was determined by performing whole genome sequencing on the strain extracted from the spinach and comparing it to the strain taken from infected individuals.
As of February 7, 2022, the provinces of Alberta and Saskatchewan in Canada reported a collective fourteen confirmed cases of E. coli O157 strain illnesses. These were reported between December 2021 and January 2022, and the Public Health Agency of Canada (PHAC), the Canadian Food Inspection Agency (CFIA), and Health Canada were able to determine a specific brand of Original Kimchi to be the source of the organism. On January 28, 2022 and February 6, 2022, the CFIA issued a recall on Hankook Original Kimchi. | 0 | Theoretical and Fundamental Chemistry |
Dendrimers are built from small molecules that end up at the surface of the sphere, and reactions proceed inward building inward and are eventually attached to a core. This method makes it much easier to remove impurities and shorter branches along the way, so that the final dendrimer is more monodisperse. However dendrimers made this way are not as large as those made by divergent methods because crowding due to steric effects along the core is limiting. | 0 | Theoretical and Fundamental Chemistry |
The Ryoji Noyori Prize is named in his honour. In 2000 Noyori became Honorary Doctor at the University of Rennes 1, where he taught in 1995, and in 2005, he became Honorary Doctor at Technical University of Munich and RWTH Aachen University, Germany. Noyori was elected a Foreign Member of the Royal Society (ForMemRS) in 2005. and an Honorary Doctorate degree from the Institute of Chemical Technology, Mumbai (formerly known as UDCT) on the 23rd day of February 2018.
He has also been awarded:
*1978 – Matsunaga prize
*1982 – Chu-Nichi Culture Award
*1985 – The Chemical Society of Japan Award
*1991 – John G. Kirkwood Award, American Chemical Society and Yale University
*1992 – Asahi Prize
*1993 – Tetrahedron Prize
*1995 – Japan Academy Prize (academics)
*1997 – Arthur C. Cope Award
*1997 – Chirality Medal
*1999 – King Faisal International Prize
*2001 – Wolf Prize in Chemistry
*2001 – Nobel Prize for Chemistry
*2009 – Lomonosov Gold Medal | 0 | Theoretical and Fundamental Chemistry |
Applied Geochemistry is a monthly peer-reviewed scientific journal published by Elsevier on behalf of the International Association of GeoChemistry. It covers research on environmental and regional geochemistry and was established in 1986. It is published by Elsevier and from 2012 to 2022 the editor-in-chief was Michael Kersten. He was succeeded by Zimeng Wang in 2023. | 0 | Theoretical and Fundamental Chemistry |
Straight-chain alkanes take the suffix "-ane" and are prefixed depending on the number of carbon atoms in the chain, following standard rules. The first few are:
For example, the simplest alkane is methane, and the nine-carbon alkane is named nonane. The names of the first four alkanes were derived from methanol, ether, propionic acid and butyric acid, respectively. The rest are named with a Greek numeric prefix, with the exceptions of nonane which has a Latin prefix, and undecane which has mixed-language prefixes.
Cyclic alkanes are simply prefixed with "cyclo-": for example, is cyclobutane (not to be confused with butene) and is cyclohexane (not to be confused with hexene).
Branched alkanes are named as a straight-chain alkane with attached alkyl groups. They are prefixed with a number indicating the carbon the group is attached to, counting from the end of the alkane chain. For example, , commonly known as isobutane, is treated as a propane chain with a methyl group bonded to the middle (2) carbon, and given the systematic name 2-methylpropane. However, although the name 2-methylpropane could be used, it is easier and more logical to call it simply methylpropane – the methyl group could not possibly occur on any of the other carbon atoms (that would lengthen the chain and result in butane, not propane) and therefore the use of the number "2" is unnecessary.
If there is ambiguity in the position of the substituent, depending on which end of the alkane chain is counted as "1", then numbering is chosen so that the smaller number is used. For example, (isopentane) is named 2-methylbutane, not 3-methylbutane.
If there are multiple side-branches of the same size alkyl group, their positions are separated by commas and the group prefixed with multiplier prefixes depending on the number of branches. For example, (neopentane) is named 2,2-dimethylpropane. If there are different groups, they are added in alphabetical order, separated by commas or hyphens. The longest possible main alkane chain is used; therefore 3-ethyl-4-methylhexane instead of 2,3-diethylpentane, even though these describe equivalent structures. The di-, tri- etc. prefixes are ignored for the purpose of alphabetical ordering of side chains (e.g. 3-ethyl-2,4-dimethylpentane, not 2,4-dimethyl-3-ethylpentane). | 0 | Theoretical and Fundamental Chemistry |
In 1966 United States President Lyndon Johnson honored Hahn, Meitner and Strassmann with the Enrico Fermi Award. The International Astronomical Union named an asteroid after him: 19136 Strassmann.
In 1985 Fritz Strassmann was recognized by Yad Vashem Institute in Jerusalem as Righteous Among the Nations (חסיד אמות העולם). Together with his wife Maria (Heckter) Strassmann, he hid a Jew in their apartment, at risk to the lives of his family. | 0 | Theoretical and Fundamental Chemistry |
In 1968, Neil Ashcroft suggested that metallic hydrogen might be a superconductor, up to room temperature (). This hypothesis is based on an expected strong coupling between conduction electrons and lattice vibrations. | 0 | Theoretical and Fundamental Chemistry |
The combination of atoms or molecules into crystals or other extended forms leads to the creation of additional energetic states. These states are numerous and therefore have a high density of states. This high density often makes the spectra weaker and less distinct, i.e., broader. For instance, blackbody radiation is due to the thermal motions of atoms and molecules within a material. Acoustic and mechanical responses are due to collective motions as well.
Pure crystals, though, can have distinct spectral transitions, and the crystal arrangement also has an effect on the observed molecular spectra. The regular lattice structure of crystals also scatters x-rays, electrons or neutrons allowing for crystallographic studies. | 0 | Theoretical and Fundamental Chemistry |
The distance is typically ≈110 pm, whereas the distance is ≈160 to 200 pm. The typical length of a hydrogen bond in water is 197 pm. The ideal bond angle depends on the nature of the hydrogen bond donor. The following hydrogen bond angles between a hydrofluoric acid donor and various acceptors have been determined experimentally: | 0 | Theoretical and Fundamental Chemistry |
The reaction was originally carried out in diethyl ether and routinely generated high yields due to the inherent irreversibly of the reaction caused by the formation of nitrogen gas. Though these reactions can be carried out at room temperature, the rate does increase at higher temperatures. Typically, the reaction is carried out at less than refluxing temperatures. The optimal reaction temperature is determined by the specific diazoalkane used. Reactions involving diazomethanes with alkyl or aryl substituents are exothermic at or below room temperature. Reactions involving diazomethanes with acyl or aroyl substituents require higher temperatures. The reaction has since been modified to proceed in the presence of Lewis acids and common organic solvents such as THF and dichloromethane. Reactions generally run at room temperature for about an hour, and the yield ranges from 70%-80% based on the choice of Lewis acid and solvent. | 0 | Theoretical and Fundamental Chemistry |
R3D measured ionizing and non-ionizing radiation as well as cosmic radiation reaching the biological samples located on the EXPOSE-E. Due to errors in data transmission or temporary termination of EXPOSE power, not all data could be acquired. Radiation was not constant during the mission. At regular intervals of about 2 months, low or almost no radiation was encountered. The radiation dose during the mission was 1823.98 MJ m−2 for PAR, 269.03 MJ m−2 for UVA, 45.73 MJ m−2 for UVB, or 18.28 MJ m−2 for UVC. Registered sunshine duration during the mission was about 152 days (about 27% of mission time). The surface of EXPOSE was most likely turned away from the Sun for considerably longer time.
The highest daily averaged absorbed dose rate of 426 μGy per day came from the South Atlantic Anomaly (SAA) region of the inner radiation belt; galactic cosmic rays (GCR) delivered a daily absorbed dose rate of 91.1 μGy per day, and the outer radiation belt (ORB) source delivered 8.6 μGy per day. | 1 | Applied and Interdisciplinary Chemistry |
When the ovarian follicles have reached a certain degree of development, induction of final oocyte maturation is performed, generally by an injection of human chorionic gonadotropin (hCG). Commonly, this is known as the "trigger shot." hCG acts as an analogue of luteinising hormone, and ovulation would occur between 38 and 40 hours after a single HCG injection, but the egg retrieval is performed at a time usually between 34 and 36 hours after hCG injection, that is, just prior to when the follicles would rupture. This avails for scheduling the egg retrieval procedure at a time where the eggs are fully mature. HCG injection confers a risk of ovarian hyperstimulation syndrome. Using a GnRH agonist instead of hCG eliminates most of the risk of ovarian hyperstimulation syndrome, but with a reduced delivery rate if the embryos are transferred fresh. For this reason, many centers will freeze all oocytes or embryos following agonist trigger. | 1 | Applied and Interdisciplinary Chemistry |
The Kovats index applies to organic compounds. The method interpolates peaks between bracketing n-alkanes. The Kovats index of n-alkanes is 100 times their carbon number, e.g. the Kovats index of n-butane is 400. The Kovats index is dimensionless, unlike retention time or retention volume. For isothermal gas chromatography, the Kovats index is given by the equation:
where the variables used are:
* , the Kováts retention index of peak i
* , the carbon number of n-alkane peak heading peak i
* , the retention time of compound i, minutes
* , the air peak, void time in average velocity , minutes
The Kovats index also applies to packed columns with an equivalent equation: | 0 | Theoretical and Fundamental Chemistry |
Loss of E-cadherin is considered to be a fundamental event in EMT. Many transcription factors (TFs) that can repress E-cadherin directly or indirectly can be considered as EMT-TF (EMT inducing TFs). SNAI1/Snail 1, SNAI2/Snail 2 (also known as Slug), ZEB1, ZEB2, TCF3 and KLF8 (Kruppel-like factor 8) can bind to the E-cadherin promoter and repress its transcription, whereas factors such as Twist, Goosecoid, TCF4 (also known as E2.2), homeobox protein SIX1 and FOXC2 (fork-head box protein C2) repress E-cadherin indirectly. SNAIL and ZEB factors bind to E-box consensus sequences on the promoter region, while KLF8 binds to promoter through GT boxes. These EMT-TFs not only directly repress E-cadherin, but also repress transcriptionally other junctional proteins, including claudins and desmosomes, thus facilitating EMT. On the other hand, transcription factors such as grainyhead-like protein 2 homologue (GRHL2), and ETS-related transcription factors ELF3 and ELF5 are downregulated during EMT and are found to actively drive MET when overexpressed in mesenchymal cells. Since EMT in cancer progression recaptures EMT in developmental programs, many of the EMT-TFs are involved in promoting metastatic events.
Several signaling pathways (TGF-β, FGF, EGF, HGF, Wnt/beta-catenin and Notch) and hypoxia may induce EMT. In particular, Ras-MAPK has been shown to activate Snail and Slug. Slug triggers the steps of desmosomal disruption, cell spreading, and partial separation at cell–cell borders, which comprise the first and necessary phase of the EMT process. On the other hand, Slug cannot trigger the second phase, which includes the induction of cell motility, repression of the cytokeratin expression, and activation of vimentin expression. Snail and Slug are known to regulate the expression of p63 isoforms, another transcription factor that is required for proper development of epithelial structures. The altered expression of p63 isoforms reduced cell–cell adhesion and increased the migratory properties of cancer cells. The p63 factor is involved in inhibiting EMT and reduction of certain p63 isoforms may be important in the development of epithelial cancers. Some of them are known to regulate the expression of cytokeratins. The phosphatidylinositol 3' kinase (PI3K)/AKT axis, Hedgehog signaling pathway, nuclear factor-kappaB and Activating Transcription Factor 2 have also been implicated to be involved in EMT.
Wnt signaling pathway regulates EMT in gastrulation, cardiac valve formation and cancer. Activation of Wnt pathway in breast cancer cells induces the EMT regulator SNAIL and upregulates the mesenchymal marker, vimentin. Also, active Wnt/beta-catenin pathway correlates with poor prognosis in breast cancer patients in the clinic. Similarly, TGF-β activates the expression of SNAIL and ZEB to regulate EMT in heart development, palatogenesis, and cancer. The breast cancer bone metastasis has activated TGF-β signaling, which contributes to the formation of these lesions. However, on the other hand, p53, a well-known tumor suppressor, represses EMT by activating the expression of various microRNAs – miR-200 and miR-34 that inhibit the production of protein ZEB and SNAIL, and thus maintain the epithelial phenotype. | 1 | Applied and Interdisciplinary Chemistry |
Rayleigh scattering, too, can be considered to be due to fluctuations in the density, composition and orientation of molecules within the transmitting medium, and hence of its refraction index, in small volumes of matter (particularly in gases or liquids). The difference is that Rayleigh scattering involves only the random and incoherent thermal fluctuations, in contrast with the correlated, periodic fluctuations (phonons) that cause Brillouin scattering. Moreover, Rayleigh scattering is elastic in that no energy is lost or gained. | 0 | Theoretical and Fundamental Chemistry |
The idea of recombinant DNA was first proposed by Peter Lobban, a graduate student of Prof. Dale Kaiser in the Biochemistry Department at Stanford University Medical School. The first publications describing the successful production and intracellular replication of recombinant DNA appeared in 1972 and 1973, from Stanford and UCSF. In 1980 Paul Berg, a professor in the Biochemistry Department at Stanford and an author on one of the first papers was awarded the Nobel Prize in Chemistry for his work on nucleic acids "with particular regard to recombinant DNA". Werner Arber, Hamilton Smith, and Daniel Nathans shared the 1978 Nobel Prize in Physiology or Medicine for the discovery of restriction endonucleases which enhanced the techniques of rDNA technology.
Stanford University applied for a U.S. patent on recombinant DNA on November 4, 1974, listing the inventors as Herbert W. Boyer (professor at the University of California, San Francisco) and Stanley N. Cohen (professor at Stanford University); this patent, U.S. 4,237,224A, was awarded on December 2, 1980. The first licensed drug generated using recombinant DNA technology was human insulin, developed by Genentech and licensed by Eli Lilly and Company. | 1 | Applied and Interdisciplinary Chemistry |
In October 2017, scientists from various European universities proposed a means for sources of GeV photons using lasers as exciters through a controlled interplay between the cascade and anomalous radiative trapping. | 0 | Theoretical and Fundamental Chemistry |
Organic mixed valence compounds are also known. Mixed valency in fact seems to be required for organic compounds to exhibit electrical conductivity. | 0 | Theoretical and Fundamental Chemistry |
H-SNIF-NMR is the official AOAC method for determining the natural vanillin.
The abundance of five monodeuterated isotopomers for vanillin can be measured by H-SNIF-NMR. The vanillin molecule is represented in figure 11, all observable sites for which the site specific deuterium concentrations can be measured are referenced with a number.
As for the wine or the fruit, the interpretation of results in terms of origin is done by comparison of the isotopic parameters of the sample analyzed with those from a group of referenced molecules of known origin.
It appears that all the origins of vanillin are well discriminated using H-NMR data. Particularly, vanillin ex-bean can well be distinguished from the other sources, as we can see in figure 12 below.
Additionally, this method is the only one to discriminate between natural and biosynthetic sources of vanillin. | 0 | Theoretical and Fundamental Chemistry |
Other traditions in Islam rejected the atomism of the Asharites and expounded on many Greek texts, especially those of Aristotle. An active school of philosophers in Al-Andalus, including the noted commentator Averroes (1126–1198 CE) explicitly rejected the thought of al-Ghazali and turned to an extensive evaluation of the thought of Aristotle. Averroes commented in detail on most of the works of Aristotle and his commentaries became very influential in Jewish and Christian scholastic thought. | 1 | Applied and Interdisciplinary Chemistry |
Cytomegalovirus (CMV) is part of the β-herpesvirus subfamily that includes roseoloviruses. CMV coevolved with an assortment of mammalian hosts, including human CMV (HCMV), murine CMV (MCMV) and rhesus CMV (RhCMV). CMVs are characterized by large DNA genomes and typically asymptomatic infection in healthy hosts.
The first investigation into cytomegalovirus (CMV) as a gene therapy vector was published in 2000. CMV's tropism for hematopoietic progenitor cells and its large genome (230 kbp) initially attracted researchers. CMV-based vaccine vectors have since been used to induce T Cell response. More recently, CMV containing telomerase and follistatin was intravenously and intranasally delivered in mouse studies with the intention of extending healthspan. | 1 | Applied and Interdisciplinary Chemistry |
Tendril perversion is a geometric phenomenon sometimes observed in helical structures in which the direction of the helix transitions between left-handed and right-handed. Such a reversal of chirality is commonly seen in helical plant tendrils and telephone handset cords.
The phenomenon was known to Charles Darwin, who wrote in 1865,
The term "tendril perversion" was coined by Alain Goriely and Michael Tabor in 1998 based on the word perversion found in 19th-century science literature. "Perversion" is a transition from one chirality to another and was known to James Clerk Maxwell, who attributed it to topologist J. B. Listing.
Tendril perversion can be viewed as an example of spontaneous symmetry breaking, in which the strained structure of the tendril adopts a configuration of minimum energy while preserving zero overall twist.
Tendril perversion has been studied both experimentally and theoretically. Gerbode et al. have made experimental studies of the coiling of cucumber tendrils. A detailed study of a simple model of the physics of tendril perversion was made by McMillen and Goriely in the early 2000s. Liu et al. showed in 2014 that "the transition from a helical to a hemihelical shape, as well as the number of perversions, depends on the height to width ratio of the strip's cross-section."
Generalized tendril perversions were put forward by Silva et al., to include perversions that can be intrinsically produced in elastic filaments, leading to a multiplicity of geometries and dynamical properties. | 0 | Theoretical and Fundamental Chemistry |
Adhesive materials fill the voids or pores of the surfaces and hold surfaces together by interlocking. Other interlocking phenomena are observed on different length scales. Sewing is an example of two materials forming a large scale mechanical bond, velcro forms one on a medium scale, and some textile adhesives (glue) form one at a small scale. | 0 | Theoretical and Fundamental Chemistry |
The Journal of Physical Chemistry Letters publishes letters, perspectives on emerging topics, editorials and viewpoints. Specific materials of interest will include, but are not limited to:
* Physical Insights into Quantum Phenomena and Function
* Physical Insights into Materials and Molecular Properties
* Physical Insights into Light Interacting with Matter
* Physical Insights into the Biosphere, Atmosphere, and Space
* Physical Insights into Chemistry, Catalysis, and Interfaces
* Physical Insights into Energy Science | 0 | Theoretical and Fundamental Chemistry |
HCN is the precursor to sodium cyanide and potassium cyanide, which are used mainly in gold and silver mining and for the electroplating of those metals. Via the intermediacy of cyanohydrins, a variety of useful organic compounds are prepared from HCN including the monomer methyl methacrylate, from acetone, the amino acid methionine, via the Strecker synthesis, and the chelating agents EDTA and NTA. Via the hydrocyanation process, HCN is added to butadiene to give adiponitrile, a precursor to Nylon-6,6.
HCN is used globally as a fumigant against many species of pest insects that infest food production facilities. Both its efficacy and method of application lead to very small amounts of the fumigant being used compared to other toxic substances used for the same purpose. Using HCN as a fumigant also has minimal environmental impact, compared to similar structural fumigant molecules such as sulfuryl fluoride, and methyl bromide. | 0 | Theoretical and Fundamental Chemistry |
Alchemy encompasses several philosophical traditions spanning some four millennia and three continents. These traditions' general penchant for cryptic and symbolic language makes it hard to trace their mutual influences and "genetic" relationships. One can distinguish at least three major strands, which appear to be mostly independent, at least in their earlier stages: Chinese alchemy, centered in China; Indian alchemy, centered on the Indian subcontinent; and Western alchemy, which occurred around the Mediterranean and whose center shifted over the millennia from Greco-Roman Egypt to the Islamic world, and finally medieval Europe. Chinese alchemy was closely connected to Taoism and Indian alchemy with the Dharmic faiths. In contrast, Western alchemy developed its philosophical system mostly independent of but influenced by various Western religions. It is still an open question whether these three strands share a common origin, or to what extent they influenced each other. | 1 | Applied and Interdisciplinary Chemistry |
Every physical theory must be verified by experiments. The spouting can experiment consists of a cylindrical vessel filled up with water and with several holes in different heights. It is designed to show that in a liquid with an open surface, pressure increases with depth. The lower a jet is on the tube, the more powerful it is. The fluid exit velocity is greater further down the tube.
The outflowing jet forms a downward parabola where every parabola reaches farther out the larger the distance between the orifice and the surface is. The shape of the parabola is only dependent on the outflow velocity and can be determined from the fact that every molecule of the liquid forms a ballistic trajectory (see projectile motion) where the initial velocity is the outflow velocity :
The results confirm the correctness of Torricelli's law very well. | 1 | Applied and Interdisciplinary Chemistry |
In fluid dynamics and electrostatics, slender-body theory is a methodology that can be used to take advantage of the slenderness of a body to obtain an approximation to a field surrounding it and/or the net effect of the field on the body. Principal applications are to Stokes flow — at very low Reynolds numbers — and in electrostatics. | 1 | Applied and Interdisciplinary Chemistry |
3-Sulfolene reacts in aqueous solution with bromine to give 3,4-dibromotetrohydrothiophene-1,1-dioxide, which can be dehydrobrominated to thiophene-1,1-dioxide with silver carbonate. Thiophene-1,1-dioxide, a highly reactive species, is also accessible via the formation of 3,4-bis(dimethylamino)tetrahydrothiophene-1,1-dioxide and successive double quaternization with methyl iodide and Hofmann elimination with silver hydroxide.
A less cumbersome two-step synthesis is the two-fold dehydrobromination of 3,4-dibromotetrohydrothiophene-1,1-dioxide with either powdered sodium hydroxide in tetrahydrofuran (THF) or with ultrasonically dispersed metallic potassium. | 0 | Theoretical and Fundamental Chemistry |
Studies on evaluating antioxidant capacity can use electrochemical methods.
Detection can be made by recombinant luminescent bacterial sensors. | 0 | Theoretical and Fundamental Chemistry |
Common applications of BLI include in vivo studies of infection (with bioluminescent pathogens), cancer progression (using a bioluminescent cancer cell line), and reconstitution kinetics (using bioluminescent stem cells).
Researchers at UT Southwestern Medical Center have shown that bioluminescence imaging can be used to determine the effectiveness of cancer drugs that choke off a tumor's blood supply. The technique requires luciferin to be added to the bloodstream, which carries it to cells throughout the body. When luciferin reaches cells that have been altered to carry the firefly gene, those cells emit light.
The BLT inverse problem of 3D reconstruction of the distribution of bioluminescent molecules from data measured on the animal surface is inherently ill-posed. The first small animal study using BLT was conducted by researchers at the University of Southern California, Los Angeles, USA in 2005. Following this development, many research groups in USA and China have built systems that enable BLT.
Mustard plants have had the gene that makes fireflies' tails glow added to them so that the plants glow when touched. The effect lasts for an hour, but an utra-sensitive camera is needed to see the glow. | 1 | Applied and Interdisciplinary Chemistry |
Double diffusive convection holds importance in natural processes and engineering applications. The effect of double diffusive convection is not limited to oceanography, also occurring in geology, astrophysics, and metallurgy. | 1 | Applied and Interdisciplinary Chemistry |
In thermodynamics, a thermodynamicist is someone who studies thermodynamic processes and phenomena, i.e. the physics that deal with mechanical action and relations of heat.
Among the well-known number of famous thermodynamicists, include Sadi Carnot, Rudolf Clausius, Willard Gibbs, Hermann von Helmholtz, and Max Planck. | 0 | Theoretical and Fundamental Chemistry |
He was born on December 31, 1905, in Ordubad.
In 1923, he entered the higher pedagogical institute of Baku. In 1926, after successful graduation from the institute he taught at secondary school for 3 years. In 1929, he became a second-year student of chemistry faculty of MSU, from which he graduated in 1932. He was a student of Nikolay Zelinsky and Aleksei Balandin and one of the first seniors of the laboratory of organic chemistry of chemistry faculty's organic chemistry cathedra with “organocatalysis” speciality. On the termination of MSU he worked in Moscow at the chemical plant No.1, and then was transferred to Azerbaijan, where he managed the Cathedra of organic chemistry of the agricultural college of Azerbaijan at first. Then he worked (1933–1945) at the Azerbaijan Research Institute of Oil, where he became the manager of laboratory. His work was dedicated to scientific problems of petrochemistry and organocatalysis and was closely connected with the development of domestic oil-refining and petrochemical industry. Some developments assumed as the basis of new industrial processes.
Starting from 1934, he led the great pedagogical work at Azerbaijan University named after S.M.Kirov, sequentially holding the positions of associate professor, professor, head of a cathedra and rector (1954–1958). In 1933, Candidate of Chemistry was conferred on Yusif Mammadaliyev without defend of dissertation.
In 1942, he became a Doctor of Chemistry and in 1943, a professor; in 1945, the academician of the Academy of Sciences of the Azerbaijan SSR (from the establishment of academy). He was the director of Oil Academy of the Azerbaijan SSR. In 1946, he was nominated to the work in the Ministry of Oil Industry, where he became the chairman of scientific-technical council of the ministry. In 1951–1954, he was the academician-secretary of physics, chemistry and oil departments of the Academy of Sciences of the Azerbaijan SSR, in 1954–1958, the rector of Azerbaijan State University.
In 1947–1951 and 1958–1961 Mammadaliyev was chosen the president of the Academy of Sciences of the Azerbaijan SSR. The Institute of Petrochemical Processes was established in Baku on Mammadaliyev's initiative.
In 1958, Mammadaliyev was chosen as the corresponding member of the Academy of Sciences of the Azerbaijan SSR.
Mammadaliyev died in 1961. | 0 | Theoretical and Fundamental Chemistry |
* Oral drug delivery: Emulsions may provide an efficient means of administering drugs that are poorly soluble or have low bioavailability or dissolution rates, increasing both dissolution rates and absorption to increase bioavailability and improve bioavailability. By increasing surface area provided by an emulsion, dissolution rates and absorption rates of drugs are increased, improving their bioavailability.
* Topical formulations: Emulsions are widely utilized as bases for topical drug delivery formulations such as creams, lotions and ointments. Their incorporation allows lipophilic as well as hydrophilic drugs to be mixed together for maximum skin penetration and permeation of active ingredients.
* Parenteral drug delivery: Emulsions serve as carriers for intravenous or intramuscular administration of drugs, solubilizing lipophilic ones while protecting from degradation and decreasing injection site irritation. Examples include propofol as a widely used anesthetic and lipid-based solutions used for total parenteral nutrition delivery.
* Ocular Drug Delivery: Emulsions can be used to formulate eye drops and other ocular drug delivery systems, increasing drug retention time in the eye and permeating through corneal barriers more easily while providing sustained release of active ingredients and thus increasing therapeutic efficacy.
* Nasal and Pulmonary Drug Delivery: Emulsions can be an ideal vehicle for creating nasal sprays and inhalable drug products, enhancing drug absorption through nasal and pulmonary mucosa while providing sustained release with reduced local irritation.
* Vaccine Adjuvants: Emulsions can serve as vaccine adjuvants by strengthening immune responses against specific antigens. Emulsions can enhance antigen solubility and uptake by immune cells while simultaneously providing controlled release, amplifying an immunological response and thus amplifying its effect.
* Taste Masking: Emulsions can be used to encase bitter or otherwise unpleasant-tasting drugs, masking their taste and increasing patient compliance - particularly with pediatric formulations.
* Cosmeceuticals: Emulsions are widely utilized in cosmeceuticals products that combine cosmetic and pharmaceutical properties. These emulsions act as carriers for active ingredients like vitamins, antioxidants and skin lightening agents to provide improved skin penetration and increased stability. | 0 | Theoretical and Fundamental Chemistry |
macroevolution - macromolecular system - macromolecule - macrophage colony-stimulating factor - major histocompatibility complex - Malpighi body - Malpighi layer - marine biology - maslinic acid - mass spectrometer - maturation-promoting factor - mechanoreceptor - medicine - meiosis - melting point - membrane glycoprotein - membrane protein - membrane topology - membrane transport - memory B cell - memory T cell - Mendelian inheritance - metabolic pathway - metabolism - metabotropic glutamate receptor - metalloprotein - metaphase - metazoa - methionine - micelle - Michaelis-Menten kinetics - microbe - microbiology - microevolution - microfilament - microfilament protein - microsatellite - microscope - microtiter plate - microtubule-associated protein - mineralocorticoid receptor - minisatellite - mitochondrial membrane - mitochondrion - mitogen receptor - mitosis - mitotic spindle - mixture - modern evolutionary synthesis - molar volume - mole (unit) - molecular biology - molecular chaperone - molecular dynamics - molecular engineering - molecular evolution - molecular mechanics - molecular modelling - molecular orbital - molecular phylogeny - molecular sequence data - molecule - monoamine - monoclonal antibody - monomer - monosaccharide - monosaccharide transport protein - morphogenesis - morphogenetic field - mos gene - Mössbauer spectroscopy - MRI - MSH - mu opioid receptor - mu-chain immunoglobulin - mucin - Muller's ratchet - multiresistance - muscarinic receptor - muscle - muscle protein - mutagen - mutation - myc gene - mycology - myelin basic protein - myeloma protein - myosin | 1 | Applied and Interdisciplinary Chemistry |
The Bürgi–Dunitz angle (BD angle) is one of two angles that fully define the geometry of "attack" (approach via collision) of a nucleophile on a trigonal unsaturated center in a molecule, originally the carbonyl center in an organic ketone, but now extending to aldehyde, ester, and amide carbonyls, and to alkenes (olefins) as well. The angle was named after crystallographers Hans-Beat Bürgi and Jack D. Dunitz, its first senior investigators.
Practically speaking, the Bürgi–Dunitz and Flippin–Lodge angles were central to the development of understanding of chiral chemical synthesis, and specifically of the phenomenon of asymmetric induction during nucleophilic attack at hindered carbonyl centers (see the Cram–Felkin–Anh and Nguyen models).
Additionally, the stereoelectronic principles that underlie nucleophiles adopting a proscribed range of Bürgi–Dunitz angles may contribute to the conformational stability of proteins and are invoked to explain the stability of particular conformations of molecules in one hypothesis of a chemical origin of life. | 0 | Theoretical and Fundamental Chemistry |
Nyholms research in inorganic chemistry was primarily concerned with the preparation of transition metal compounds, particularly those involving organo-arsenic ligands. His interest in organoarsenic chemistry was fostered at the University of Sydney by George Joseph Burrows (1888–1950). Using the strong chelating ligand diars, Nyholm demonstrated a range of oxidation states and coordination numbers for several of the transition metals. Nyholm noted that the term unusual valence state had an historical, but not chemical significance. The definition of usual oxidation state refers to oxidation states that are stable in environments made up of those chemical species that were common in classical inorganic compounds, e.g. oxides, water and other simple oxygen donors, the halogens, excluding fluorine, and sulphur. Nowadays, however, such species constitute only a minority of the vast number of donor atoms and ligands that can be attached to metal.'
After joining Sydney Technology college in 1940 Nyholm formed a close personal friendship with Francis (Franky) Dwyer and they collaborated in their research. Despite heavy teaching loads, between 1942 and 1947 they reported complexes of rhodium, iridium, and osmium in seventeen papers in the Journal and Proceedings of the Royal Society of New South Wales.
One of Nyholm's early successes was the preparation of an octahedral complex of trivalent nickel [Ni(diars)Cl]Cl, by aerial oxidation of the red salt of bivalent nickel [Ni(diars)]Cl. He also described stable complexes of quadrivalent nickel such as the deep blue [Ni(diars)Cl] [ClO], by nitric acid oxidation of the trivalent complex. This stabilisation of higher oxidation states became significant in the Nyholm-Rail reaction where the ditertiary arsine, diars undergoes a condensation reaction to a tritertiary arsine, triars. Nyholm prepared examples of divalent octahedral complexes of the type M(diars)X, where X is Cl, Br or I, and M is Cr, Mn, Fe, Co, Ni, Mo, Tc, Ru, Pd, W, Re, Os, and Pt.
Many of these divalent complexes are sensitive to aerial oxidation. The chromium complex is oxidized by water. Indeed, previous attempts to prepare Cr(diars)X had failed. The chromium compounds were eventually synthesized by his co-worker Anthony Nicholl Rail only a month before Nyholm's death, using rigorous air-free techniques.
Together with Professor Ronald Gillespie, Nyholm developed the VSEPR (Valence shell electron pair repulsion) theory for the simple prediction of molecular geometry. This theory emphasized classical pictures of bonding, adapted to include features of quantum theory, but focusing on electron clouds of varying density within a probability envelope. | 0 | Theoretical and Fundamental Chemistry |
ASCOT-LLA manufacturer-sponsored study addressed the benefit of atorvastatin 10 mg (a cholesterol-lowering drug) in patients with hypertension (high blood pressure) but no previous cardiovascular disease (primary prevention). The trial ran for 3.3 years, and during this period the relative risk of a "primary event" (heart attack) was reduced by 36% (relative risk reduction, RRR). The absolute risk reduction (ARR), however, was much smaller, because the study group did not have a very high rate of cardiovascular events over the study period: 2.67% in the control group, compared to 1.65% in the treatment group. Taking atorvastatin for 3.3 years, therefore, would lead to an ARR of only 1.02% (2.67% minus 1.65%). The number needed to treat to prevent one cardiovascular event would then be 98.04 for 3.3 years. | 1 | Applied and Interdisciplinary Chemistry |
The society aims to accelerate the rate of scientific innovations being commercialised by industry to benefit society. It does this through promoting collaborations between scientists and industrialists, running technical and innovation conferences, building communities across academia and industry and publishing scientific content through its journals and digital platforms.
It also promotes science education. | 1 | Applied and Interdisciplinary Chemistry |
Antiferroelectricity is a physical property of certain materials. It is closely related to ferroelectricity; the relation between antiferroelectricity and ferroelectricity is analogous to the relation between antiferromagnetism and ferromagnetism.
An antiferroelectric material consists of an ordered (crystalline) array of electric dipoles (from the ions and electrons in the material), but with adjacent dipoles oriented in opposite (antiparallel) directions (the dipoles of each orientation form interpenetrating sublattices, loosely analogous to a checkerboard pattern). This can be contrasted with a ferroelectric, in which the dipoles all point in the same direction.
In an antiferroelectric, unlike a ferroelectric, the total, macroscopic spontaneous polarization is zero, since the adjacent dipoles cancel each other out.
Antiferroelectricity is a property of a material, and it can appear or disappear (more generally, strengthen or weaken) depending on temperature, pressure, external electric field, growth method, and other parameters. In particular, at a high enough temperature, antiferroelectricity disappears; this temperature is known as the Néel point or Curie point. | 0 | Theoretical and Fundamental Chemistry |
All other diatomic molecules are chemical compounds of two different elements. Many elements can combine to form heteronuclear diatomic molecules, depending on temperature and pressure.
Examples are gases carbon monoxide (CO), nitric oxide (NO), and hydrogen chloride (HCl).
Many 1:1 binary compounds are not normally considered diatomic because they are polymeric at room temperature, but they form diatomic molecules when evaporated, for example gaseous MgO, SiO, and many others. | 0 | Theoretical and Fundamental Chemistry |
The optical dispersion of fused quartz can be approximated by the following Sellmeier equation:
where the wavelength is measured in micrometers. This equation is valid between 0.21 and 3.71 μm and at 20 °C. Its validity was confirmed for wavelengths up to 6.7 μm. Experimental data for the real (refractive index) and imaginary (absorption index) parts of the complex refractive index of fused quartz reported in the literature over the spectral range from 30 nm to 1000 μm have been reviewed by Kitamura et al. and are [http://www.seas.ucla.edu/~pilon/downloads.htm available online].
Its quite high Abbe Number of 67.8 makes it among the lowest dispersion glasses at visible wavelengths, as well as having an exceptionally low refractive index in the visible (n = 1.4585). Note that fused quartz has a very different and lower refractive index compared to crystalline quartz which is birefringent with refractive indices n = 1.5443 and n = 1.5534 at the same wavelength. Although these forms have the same chemical formula, their differing structures result in different optical and other physical properties. | 1 | Applied and Interdisciplinary Chemistry |
Substantial decreases in extracellular Ca ion concentrations may result in a condition known as hypocalcemic tetany, which is marked by spontaneous motor neuron discharge. In addition, severe hypocalcaemia will begin to affect aspects of blood coagulation and signal transduction.
Ca ions can damage cells if they enter in excessive numbers (for example, in the case of excitotoxicity, or over-excitation of neural circuits, which can occur in neurodegenerative diseases, or after insults such as brain trauma or stroke). Excessive entry of calcium into a cell may damage it or even cause it to undergo apoptosis, or death by necrosis. Calcium also acts as one of the primary regulators of osmotic stress (osmotic shock). Chronically elevated plasma calcium (hypercalcemia) is associated with cardiac arrhythmias and decreased neuromuscular excitability. One cause of hypercalcemia is a condition known as hyperparathyroidism. | 1 | Applied and Interdisciplinary Chemistry |
During the 1880s, Moissan focused on fluorine chemistry and especially the production of fluorine itself. The existence of the element had been well known for many years, but all attempts to isolate it had failed, and some experimenters had died in the attempt.
He had no laboratory of his own, but borrowed lab space from others, including Charles Friedel. There he had access to a strong battery consisting of 90 Bunsen cells which made it possible to observe a gas produced by the electrolysis of molten arsenic trichloride; the gas was reabsorbed by the arsenic trichloride.
Moissan eventually succeeded in isolating fluorine in 1886 by the electrolysis of a solution of potassium hydrogen difluoride (KHF) in liquid hydrogen fluoride (HF). The mixture was necessary because hydrogen fluoride is a nonconductor. The device was built with platinum-iridium electrodes in a platinum holder and the apparatus was cooled to −50 °C. The result was the complete separation of the hydrogen produced at the negative electrode from the fluorine produced at the positive one, first achieved on 26 June 1886. This remains the current standard method for commercial fluorine production. The French Academy of Science sent three representatives, Marcellin Berthelot, Henri Debray, and Edmond Frémy, to verify the results, but Moissan was unable to reproduce them, owing to the absence from the hydrogen fluoride of traces of potassium fluoride present in the previous experiments. After resolving the problem and demonstrating the production of fluorine several times, he was awarded a prize of 10,000 francs. For the first successful isolation, he was awarded the 1906 Nobel Prize in Chemistry. Following his grand achievement, his research focused on characterizing fluorine's chemistry. He discovered numerous fluorine compounds, such as (together with Paul Lebeau) sulfur hexafluoride in 1901. | 0 | Theoretical and Fundamental Chemistry |
Lauterbur died aged 77 in March 2007 of kidney disease at his home in Urbana, Illinois. University of Illinois Chancellor Richard Herman said, "Paul's influence is felt around the world every day, every time an MRI saves the life of a daughter or a son, a mother or a father." | 0 | Theoretical and Fundamental Chemistry |
Liquation is a metallurgical method for separating metals from an ore or alloy. The material must be heated until one of the metals starts to melt and drain away from the other and can be collected. This method was largely used to remove lead containing silver from copper, but it can also be used to remove antimony from ore minerals, and refine tin.
The 16th-century process of separating copper and silver using liquation, described by Georg Agricola in his 1556 treatise De re metallica, remained almost unchanged until the 19th century when it was replaced by cheaper and more efficient processes such as sulphatization and eventually electrolytic methods. | 1 | Applied and Interdisciplinary Chemistry |
Platinum-samarium is a binary inorganic compound of platinum and samarium with the chemical formula PtSm. This intermetallic compound forms crystals. | 1 | Applied and Interdisciplinary Chemistry |
Trichlorofluoromethane can be obtained by reacting carbon tetrachloride with hydrogen fluoride at 435 °C and 70 atm, producing a mixture of trichlorofluoromethane, tetrafluoromethane and dichlorodifluoromethane in a ratio of 77:18:5. The reaction can also be carried out in the presence of antimony(III) chloride or antimony(V) chloride:
Trichlorofluoromethane is also formed as one of the byproducts when graphite reacts with chlorine and hydrogen fluoride at 500 °C.
Sodium hexafluorosilicate under pressure at 270 °C, titanium(IV) fluoride, chlorine trifluoride, cobalt(III) fluoride, iodine pentafluoride, and bromine trifluoride are also suitable fluorinating agents for carbon tetrachloride.
Trichlorofluoromethane was included in the production moratorium in the Montreal Protocol of 1987. It is assigned an ozone depletion potential of 1.0, and U.S. production was ended on January 1, 1996. | 1 | Applied and Interdisciplinary Chemistry |
NETA is available in the form of tablets for use by mouth both alone and in combination with estrogens including estradiol, estradiol valerate, and ethinylestradiol. Transdermal patches providing a combination of 50 μg/day estradiol and 0.14 or 0.25 mg/day NETA are available under the brand names CombiPatch and Estalis.
NETA was previously available for use by intramuscular injection in the form of ampoules containing 20 mg NETA, 5 mg estradiol benzoate, 8 mg estradiol valerate, and 180 mg testosterone enanthate in oil solution under the brand name Ablacton to suppress lactation in postpartum women. | 1 | Applied and Interdisciplinary Chemistry |
The Kelvin equation indicates that as P/P increases inside a capillary, the radius of curvature will also increase, creating a flatter interface. (Note: This is not to say that larger radii of curvature result in more vapor condensation. See the discussion on contact angle below.) Figure 2 above demonstrates this dependence in a simple situation whereby the capillary radius is expanding toward the opening of the capillary and thus vapor condensation occurs smoothly over a range of vapor pressures. In a parallel situation, where the capillary radius is constant throughout its height, vapor condensation would occur much more rapidly, reaching the equilibrium radius of curvature (Kelvin radius) as quickly as possible. This dependence on pore geometry and curvature can result in hysteresis and vastly different liquid/vapor equilibria over very small ranges in pressure.
It is also worthy to mention that different pore geometries result in different types of curvature. In scientific studies of capillary condensation, the hemispherical meniscus situation (that resulting from a perfectly cylindrical pore) is most often investigated due to its simplicity. Cylindrical menisci are also useful systems because they typically result from scratches, cuts, and slit-type capillaries in surfaces. Many other types of curvature are possible and equations for the curvature of menisci are readily available at numerous sources. Those for the hemispherical and cylindrical menisci are shown below.
General Curvature Equation:
Cylinder:
Hemisphere: | 1 | Applied and Interdisciplinary Chemistry |
In chemistry, the effective molarity (denoted EM) is defined as the ratio between the first-order rate constant of an intramolecular reaction and the second-order rate constant of the corresponding intermolecular reaction (kinetic effective molarity) or the ratio between the equilibrium constant of an intramolecular reaction and the equilibrium constant of the corresponding intermolecular reaction (thermodynamic effective molarity).
EM has the dimension of concentration. High EM values always indicate greater ease of intramolecular processes over the corresponding intermolecular ones. Effective molarities can be used to get a deeper understanding of the effects of intramolecularity on reaction courses. | 0 | Theoretical and Fundamental Chemistry |
Cyclodextrins are well established hosts for the formation of inclusion compounds. Illustrative is the case of ferrocene which is inserted into the cyclodextrin at 100 °C under hydrothermal conditions.
Cyclodextrin also forms inclusion compounds with fragrances. As a result, the fragrance molecules have a reduced vapor pressure and are more stable towards exposure to light and air. When incorporated into textiles the fragrance lasts much longer due to the slow-release action. | 0 | Theoretical and Fundamental Chemistry |
Two basic forms of leaves can be described considering the way the blade (lamina) is divided. A simple leaf has an undivided blade. However, the leaf may be dissected to form lobes, but the gaps between lobes do not reach to the main vein. A compound leaf has a fully subdivided blade, each leaflet of the blade being separated along a main or secondary vein. The leaflets may have petiolules and stipels, the equivalents of the petioles and stipules of leaves. Because each leaflet can appear to be a simple leaf, it is important to recognize where the petiole occurs to identify a compound leaf. Compound leaves are a characteristic of some families of higher plants, such as the Fabaceae. The middle vein of a compound leaf or a frond, when it is present, is called a rachis.
;Palmately compound: The leaflets all have a common point of attachment at the end of the petiole, radiating like fingers of a hand; for example, Cannabis (hemp) and Aesculus (buckeyes).
;Pinnately compound: Leaflets are arranged either side of the main axis, or rachis.
;Bipinnately compound: Leaves are twice divided: the leaflets (technically "subleaflets") are arranged along a secondary axis that is one of several branching off the rachis. Each leaflet is called a pinnule. The group of pinnules on each secondary vein forms a pinna; for example, Albizia (silk tree).
;Trifoliate (or trifoliolate): A pinnate leaf with just three leaflets; for example, Trifolium (clover), Laburnum (laburnum), and some species of Toxicodendron (for instance, poison ivy).
;Pinnatifid: Pinnately dissected to the central vein, but with the leaflets not entirely separate; for example, Polypodium, some Sorbus (whitebeams). In pinnately veined leaves the central vein is known as the midrib. | 0 | Theoretical and Fundamental Chemistry |
Selenium has bimodal biological action depending on the concentration. At low nutritional doses, selenium acts as an antioxidant through selenoproteins, scavenging ROS, supporting cell survival and growth; while, at supra-nutritional higher pharmacological doses, selenium acts as a pro-oxidant generating ROS and inducing cell death. In cancer, studies have been conducted mostly on the benefits of selenium intake in reducing the risk of cancer incidence at the nutritional level; however, fewer studies have explored the effects of supra-nutritional or pharmacological doses of selenium on cancer.
"Although an inverse association between selenium exposure and the risk of some types of cancer was found in some observational studies, this cannot be taken as evidence of a causal relation, and these results should be interpreted with caution... Conflicting results including inverse, null and direct associations have been reported for some cancer types... RCTs assessing the effects of selenium supplementation on cancer risk have yielded inconsistent results... To date, no convincing evidence suggests that selenium supplements can prevent cancer in humans." | 1 | Applied and Interdisciplinary Chemistry |
For a process that occurs at constant temperature and pressure, spontaneity can be determined using the change in Gibbs free energy, which is given by:
where the sign of ΔG depends on the signs of the changes in enthalpy (ΔH) and entropy (ΔS). If these two signs are the same (both positive or both negative), then the sign of ΔG will change from positive to negative (or vice versa) at the temperature
In cases where ΔG is:
* negative, the process is spontaneous and may proceed in the forward direction as written.
* positive, the process is non-spontaneous as written, but it may proceed spontaneously in the reverse direction.
* zero, the process is at equilibrium, with no net change taking place over time.
This set of rules can be used to determine four distinct cases by examining the signs of the ΔS and ΔH.
* When ΔS > 0 and ΔH < 0, the process is always spontaneous as written.
* When ΔS < 0 and ΔH > 0, the process is never spontaneous, but the reverse process is always spontaneous.
* When ΔS > 0 and ΔH > 0, the process will be spontaneous at high temperatures and non-spontaneous at low temperatures.
* When ΔS < 0 and ΔH < 0, the process will be spontaneous at low temperatures and non-spontaneous at high temperatures.
For the latter two cases, the temperature at which the spontaneity changes will be determined by the relative magnitudes of ΔS and ΔH. | 0 | Theoretical and Fundamental Chemistry |
Agriculture managements approaches such as monoculture and chemical fertilization often leads to soil problems such as soil acidification, degradation, and soil-borne diseases, which ultimately have a negative impact on agricultural productivity and sustainability. | 0 | Theoretical and Fundamental Chemistry |
Hydrophobic sand (or magic sand) is a toy made from sand coated with a hydrophobic compound. The presence of the hydrophobic compound causes the grains of sand to adhere to one another and form cylinders (to minimize surface area) when exposed to water, and form a pocket of air around the sand. The pocket of air makes magic sand unable to get wet. A variation of this, kinetic sand, has several of the same properties, but acts like wet sand that will not dry out. Hydrophobic sand, whether the wet or dry type, will not mix with water. | 1 | Applied and Interdisciplinary Chemistry |
Numerous studies and reviews have been published with respect to GIC used in primary teeth restorations. Findings of a systematic review and meta-analysis suggested that conventional glass ionomers were not recommended for Class II restorations in primary molars. This material showed poor anatomical form and marginal integrity, and composite restorations were shown to be more successful than GIC when good moisture control could be achieved. Resin modified glass ionomer cements (RMGIC) were developed to overcome the limitations of the conventional glass ionomer as a restorative material. A systematic review supports the use of RMGIC in small to moderate sized class II cavities, as they are able to withstand the occlusal forces on primary molars for at least one year. With their desirable fluoride releasing effect, RMGIC may be considered for Class I and Class II restorations of primary molars in high caries risk population. | 0 | Theoretical and Fundamental Chemistry |
Sodium is the primary cation (positively charged ion) in extracellular fluids in animals and humans. These fluids, such as blood plasma and extracellular fluids in other tissues, bathe cells and carry out transport functions for nutrients and wastes. Sodium is also the principal cation in seawater, although the concentration there is about 3.8 times what it is normally in extracellular body fluids. | 1 | Applied and Interdisciplinary Chemistry |
A pepper-spray projectile may be a sphere, hence the name pepper-ball, but it may also come in other shapes. The irritant payload may differ from product to product but is usually a powder, less frequently a liquid, gas or aerosol. Some companies offer different substances as payload for their projectiles and launcher systems, so potential sellers can choose a substance that is certified for use in their country. Also, projectiles with an inert dummy payload are often offered, for training and testing purposes.
A powder called PAVA (capsaicin II) pepper is often used. PAVA is a capsaicinoid that can be synthesized for cheaper than grown peppers, although it is also found in nature.
Pepper-spray weapons systems are used by law enforcement, military and other organizations, and individuals. The weapon is used generally in the role of stand-off weapons, where physical proximity to a suspect is deemed dangerous but deadly force is not warranted. The systems are not limited to classic standoff situations and allow agents to apply as many rounds as required to bring individual suspects, multiple suspects, or crowds into compliance. | 1 | Applied and Interdisciplinary Chemistry |
Activated Ras then activates the protein kinase activity of a RAF kinase. The RAF kinase phosphorylates and activates a MAPK/ERK Kinase (MEK1 or MEK2). The MEK phosphorylates and activates a mitogen-activated protein kinase (MAPK).
RAF and MAPK/ERK are both serine/threonine-specific protein kinases. MEK is a serine/tyrosine/threonine kinase.
In a technical sense, RAF, MEK, and MAPK are all mitogen-activated kinases, as is MNK (see below). MAPKs were originally called "extracellular signal-regulated kinases" (ERKs) and "microtubule associated protein kinases" (MAPKs). One of the first proteins known to be phosphorylated by ERK was a microtubule-associated protein (MAP). As discussed below, many additional targets for phosphorylation by MAPK were later found, and the protein was renamed "mitogen-activated protein kinase" (MAPK). The series of kinases from RAF to MEK to MAPK is an example of a protein kinase cascade. Such series of kinases provide opportunities for feedback regulation and signal amplification. | 1 | Applied and Interdisciplinary Chemistry |
At low concentrations of TNP-ATP (≤1 μM), fluorescent intensity is proportional to the concentration of TNP added. However, at concentrations exceeding 1 μM, inner filter effects cause this relationship to no longer be linear. To correct this, researchers must determine the ratio of the predicted theoretical fluorescence intensity (assuming linearity) to the observed fluorescence intensity and then apply this correction factor. However, in most cases, researchers will try to keep the concentration of TNP to lower than 1 μM.
To determine binding affinities, TNP-ATP is added to a solution and then titrated with protein. This produces a saturation curve from which the binding affinity can be determined. The number of binding sites may also be determined through this saturation curve by looking to see if there are sudden changes in slope. One can also titrate a fixed amount of protein with increasing additions of TNP-ATP to obtain a saturation curve. To do so, however, may get complicated due to the inner filter effects that will need to be corrected for.
To determine dissociation constants, TNP-ATP can be competed off of a protein with ATP. The value of the dissociation constant K for a single-site binding can then be obtained by applying the Langmuir equation for a curve fit:
where RFU is relative fluorescent units, RFU is the fluorescence observed, RFU is the fluorescence of free TNP-ATP, and RFU is the fluorescence of TNP-ATP when completely bound to a protein.
To measure an ATP competitor, one can add competitor to pre-incubated samples of protein:TNP-ATP. The fraction of TNP-ATP bound to the protein can be calculated via:
where θ is that fraction, and RFU is the value of fluorescence intensity at saturation, meaning when 100% of TNP-ATP is bound.
The dissociation constants for TNP and competitor can then be calculated through the equation:
For reasons not yet fully understood, TNP-ATP typically binds the ATP binding sites of proteins and enzymes anywhere from one to three times tighter than regular ATP. The dissociation constants are usually around 0.3–50 μM. | 0 | Theoretical and Fundamental Chemistry |
Lytic and lysogenic viruses have different lifestyles which impact what AMGs they acquire. Lytic viruses tend to use AMGs to repurpose host cell metabolism and steal nutrients when in high cell density. Therefore, AMGs related to metabolism and transport are found more abundantly in lytic viruses. Lytic viruses also encompass a more diverse set of AMGs than lysogenic viruses, in part due to their larger host range and higher infection frequency. Temperate viruses, on the other hand, may employ AMGs to improve host fitness and virulence due to their often longer lifespan in the cell as a prophage. Gene density in these viruses is higher when compared to their lytic counterparts. Higher rates of HGT in lysogenic viruses allows for more AMG transfer but also lowers overall gene diversity.
Photosynthesis capacity has also been correlated to AMG diversity. Aphotic viral communities possess greater AMG diversity than those in the photic zone. | 1 | Applied and Interdisciplinary Chemistry |
A geroprotector is a senotherapeutic that aims to affect the root cause of aging and age-related diseases, and thus prolong the life span of animals. Some possible geroprotectors include melatonin, carnosine, metformin, rapamycin, nicotinamide mononucleotide (NMN) and delta sleep-inducing peptide. | 1 | Applied and Interdisciplinary Chemistry |
The Froehde reagent is used as a simple spot-test to presumptively identify alkaloids, especially opioids, as well as other compounds. It is composed of a mixture of molybdic acid or a molybdate salt dissolved in hot, concentrated sulfuric acid, which is then dripped onto the substance being tested.
The United States Department of Justice method for producing the reagent is the addition of 100 ml of hot, concentrated (95–98%) sulfuric acid to 0.5 g of sodium molybdate or molybdic acid.
The Virginia Department of Forensic Science method uses 0.5 g ammonium molybdate per 100 ml HSO (conc.)
Unheated sulfuric acid can be used to prepare the reagent in a less dangerous manner, but 2–4 hours must be allowed for the molybdate to dissolve. | 0 | Theoretical and Fundamental Chemistry |
Where there are more than two centres that are bridged a bridging index is added as a subscript. For example in basic beryllium acetate which can be visualised as a tetrahedral arrangement of Be atoms linked by 6 acetate ions forming a cage with a central oxide anion, the formula and name are as follows:
:[Be(μ-O)(μ-OCMe)]
:hexakis(μ-acetato-κO:κ)-μ-oxido-tetrahedro-tetraberyllium
The μ describes the bridging of the central oxide ion. (Note the use of the kappa convention to describe the bridging of the acetate ion where both oxygen atoms are involved.) In the name where a ligand is involved in different modes of bridging, the multiple bridging is listed in decreasing order of complexity, e.g. μ bridging before μ bridging. | 0 | Theoretical and Fundamental Chemistry |
Iodine in food is absorbed by the body and preferentially concentrated in the thyroid where it is needed for the functioning of that gland. When I is present in high levels in the environment from radioactive fallout, it can be absorbed through contaminated food, and will also accumulate in the thyroid. As it decays, it may cause damage to the thyroid. The primary risk from exposure to I is an increased risk of radiation-induced cancer in later life. Other risks include the possibility of non-cancerous growths and thyroiditis.
The risk of thyroid cancer in later life appears to diminish with increasing age at time of exposure. Most risk estimates are based on studies in which radiation exposures occurred in children or teenagers. When adults are exposed, it has been difficult for epidemiologists to detect a statistically significant difference in the rates of thyroid disease above that of a similar but otherwise-unexposed group.
The risk can be mitigated by taking iodine supplements, raising the total amount of iodine in the body and, therefore, reducing uptake and retention in the face and chest and lowering the relative proportion of radioactive iodine. However, such supplements were not consistently distributed to the population living nearest to the Chernobyl nuclear power plant after the disaster, though they were widely distributed to children in Poland.
Within the US, the highest I fallout doses occurred during the 1950s and early 1960s to children having consumed fresh milk from sources contaminated as the result of above-ground testing of nuclear weapons. The National Cancer Institute provides additional information on the health effects from exposure to I in fallout, as well as individualized estimates, for those born before 1971, for each of the 3070 counties in the USA. The calculations are taken from data collected regarding fallout from the nuclear weapons tests conducted at the Nevada Test Site.
On 27 March 2011, the Massachusetts Department of Public Health reported that I was detected in very low concentrations in rainwater from samples collected in Massachusetts, USA, and that this likely originated from the Fukushima power plant. Farmers near the plant dumped raw milk, while testing in the United States found 0.8 pico-curies per liter of iodine-131 in a milk sample, but the radiation levels were 5,000 times lower than the FDA's "defined intervention level".
The levels were expected to drop relatively quickly | 0 | Theoretical and Fundamental Chemistry |
KCS Uploads about five to six questions every two weeks on KChO website. Students who are studying for KChO can download the questions and try to solve them. Anyone can download the answers and official solutions there after a week. Even if the person is not joining the KChO, the person can download the questions and answers at the KChO website. | 1 | Applied and Interdisciplinary Chemistry |
* (with Marie Curie)
* [https://archive.today/20140422005504/http://www.youscribe.com/catalogue/rapports-et-theses/savoirs/science-de-la-nature/sur-le-radium-et-l-uranium-contenus-dans-les-mineraux-radioactifs-1507892 Sur le radium et luranium contenus dans les mineraux radioactifs], Comptes Rendus' 148:1451 (1909)
* Ratio Between Uranium and Radium in the Radio-active Minerals, Comptes Rendus 149:267 (1909).
* [http://radium.journaldephysique.org/index.php?option=com_toc&url=/articles/radium/abs/1911/07/contents/contents.html Sur le rapport entre luranium et le radium dans les mineraux actifs], Radium' 8:256 (1911). | 0 | Theoretical and Fundamental Chemistry |
Nuclear fallout from Cold War weapons testing settled in the United States throughout the Mississippi River System. Tritium concentrations can be used to understand the residence times of continental hydrologic systems (as opposed to the usual oceanic hydrologic systems) which include surface waters such as lakes, streams, and rivers. Studying these systems can also provide societies and municipals with information for agricultural purposes and overall river water quality.
In a 2004 study, several rivers were taken into account during the examination of tritium concentrations (starting in the 1960s) throughout the Mississippi River Basin: Ohio River (largest input to the Mississippi River flow), Missouri River, and Arkansas River. The largest tritium concentrations were found in 1963 at all the sampled locations throughout these rivers and correlate well with the peak concentrations in precipitation due to the nuclear bomb tests in 1962. The overall highest concentrations occurred in the Missouri River (1963) and were greater than 1,200 TU while the lowest concentrations were found in the Arkansas River (never greater than 850 TU and less than 10 TU in the mid-1980s).
Several processes can be identified using the tritium data from the rivers: direct runoff and outflow of water from groundwater reservoirs. Using these processes, it becomes possible to model the response of the river basins to the transient tritium tracer. Two of the most common models are the following:
; Piston-flow approach: tritium signal appears immediately; and
; Well-mixed reservoir approach: outflow concentration depends upon the residence time of the basin water
For the Ohio River, the tritium data indicated that about 40% of the flow was composed of precipitation with residence times of less than one year (in the Ohio basin) and older waters consisted of residence times of about ten years. Thus, the short residence times (less than one year) corresponded to the "prompt-flow" component of the two-member mixing model. As for the Missouri River, results indicated that residence times were approximately four years with the prompt-flow component being around 10% (these results are due to the series of dams in the area of the Missouri River).
As for the mass flux of tritium through the main stem of the Mississippi River into the Gulf of Mexico, data indicated that approximately 780 grams of tritium has flowed out of the River and into the Gulf between 1961 and 1997, an average of 21.7 grams/yr and 7.7 PBq/yr. Current fluxes through the Mississippi River are 1 to 2 grams, per year as opposed to the pre-bomb period fluxes of roughly 0.4 grams per year. | 0 | Theoretical and Fundamental Chemistry |
Miray Bekbölet is a Turkish environmental chemist researching oxidation techniques, photocatalytic and photolytic reactions, adsorption/bio-oxidation processes in aquatic systems, and drinking water quality. She is a professor of environmental chemistry at the Boğaziçi University Institute of Environmental Sciences. | 0 | Theoretical and Fundamental Chemistry |
Superconductivity was discovered on April 8, 1911, by Heike Kamerlingh Onnes, who was studying the resistance of solid mercury at cryogenic temperatures using the recently produced liquid helium as a refrigerant. At the temperature of 4.2 K, he observed that the resistance abruptly disappeared. In the same experiment, he also observed the superfluid transition of helium at 2.2 K, without recognizing its significance. The precise date and circumstances of the discovery were only reconstructed a century later, when Onnes's notebook was found. In subsequent decades, superconductivity was observed in several other materials. In 1913, lead was found to superconduct at 7 K, and in 1941 niobium nitride was found to superconduct at 16 K.
Great efforts have been devoted to finding out how and why superconductivity works; the important step occurred in 1933, when Meissner and Ochsenfeld discovered that superconductors expelled applied magnetic fields, a phenomenon which has come to be known as the Meissner effect. In 1935, Fritz and Heinz London showed that the Meissner effect was a consequence of the minimization of the electromagnetic free energy carried by superconducting current. | 0 | Theoretical and Fundamental Chemistry |
As predicted by studies in animal models, drugs were most effective when used in patients with tumours of smaller volume. Another important strategy developed from this — if the tumour burden could be reduced first by surgery, then chemotherapy may be able to clear away any remaining malignant cells, even if it would not have been potent enough to destroy the tumor in its entirety. This approach was termed "adjuvant therapy".
Emil Frei first demonstrated this effect — high doses of methotrexate prevented recurrence of osteosarcoma following surgical removal of the primary tumour. 5-fluorouracil, which inhibits thymidylate synthase, was later shown to improve survival when used as an adjuvant to surgery in treating patients with colon cancer. Similarly, the landmark trials of Bernard Fisher, chair of the National Surgical Adjuvant Breast and Bowel Project, and of Gianni Bonadonna, working in the Istituto Nazionale Tumori di Milano, Italy, proved that adjuvant chemotherapy after complete surgical resection of breast tumours significantly extended survival — particularly in more advanced cancer. | 1 | Applied and Interdisciplinary Chemistry |
To discuss the visibility of defects in topographic images according to theory, consider the exemplary case of a single dislocation: It will give rise to contrast in topography only if the lattice planes involved in diffraction are distorted in some way by the existence of the dislocation. This is true in the case of an edge dislocation if the scattering vector of the Bragg reflection used is parallel to the Burgers vector of the dislocation, or at least has a component in the plane perpendicular to the dislocation line, but not if it is parallel to the dislocation line. In the case of a screw dislocation, the scattering vector has to have a component along the Burgers vector, which is now parallel to dislocation line. As a rule of thumb, a dislocation will be invisible in a topograph if the vector product
is zero.
(A more precise rule will have to distinguish between screw and edge dislocations and to also take the direction of the dislocation line into account – see e.g. [http://www.msel.nist.gov/practiceguides/SP960_10.pdf].)
If a defect is visible, often there occurs not only one, but several distinct images of it on the topograph. Theory predicts three images of single defects: The so-called direct image, the kinematical image, and the intermediary image.
For details see e.g. (Authier 2003). | 0 | Theoretical and Fundamental Chemistry |
Copper technology may date back to the 4th millennium BCE in the Himalaya region.
It is the first element to be discovered in metallurgy,
Copper and its alloys were also used to create copper-bronze images such as Buddhas or Hindu/Mahayana Buddhist deities. Xuanzang also noted that there were copper-bronze Buddha images in Magadha. In Varanasi, each stage of the image manufacturing process is handled by a specialist.
Other metal objects made by Indian artisans include lamps. Copper was also a component in the razors for the tonsure ceremony.
One of the most important sources of history in the Indian subcontinent are the royal records of grants engraved on copper-plate grants (tamra-shasan or tamra-patra). Because copper does not rust or decay, they can survive indefinitely. Collections of archaeological texts from the copper-plates and rock-inscriptions have been compiled and published by the Archaeological Survey of India during the past century. The earliest known copper-plate known as the Sohgaura copper-plate is a Maurya record that mentions famine relief efforts. It is one of the very few pre-Ashoka Brahmi inscriptions in India. | 1 | Applied and Interdisciplinary Chemistry |
William Flockhart, L.R.C.S.E. (1808 – 1871) was a Scottish chemist, a pharmacist who provided chloroform to Doctor (later Sir) James Young Simpson for his anaesthesia experiment at 52 Queen Street, Edinburgh on 4 November 1847. This was the first use of this chemical on humans when Simpson tried it on himself and a few friends, and then used it for pain relief in obstetrics, and surgery. This changed medical practice for over a century, according to the British Medical Journal. | 1 | Applied and Interdisciplinary Chemistry |
WEAP (the Water Evaluation and Planning system) is a model-building tool for water resource planning and policy analysis that is distributed at no charge to non-profit, academic, and governmental organizations in developing countries.
WEAP can be used to create simulations of water demand, supply, runoff, evapotranspiration, water allocation, infiltration, crop irrigation requirements, instream flow requirements, ecosystem services, groundwater and surface storage, reservoir operations, pollution generation, treatment, discharge, and instream water quality. The simulations can be created under scenarios of varying policy, hydrology, climate, land use, technology, and socio-economic factors. WEAP links to the USGS MODFLOW groundwater flow model and the US EPA QUAL2K surface water quality model.
WEAP was created in 1988 and continues to be developed and supported by the U.S. Center of the Stockholm Environment Institute, a non-profit research institute based at Tufts University in Somerville, Massachusetts. It is used for climate change vulnerability studies and adaptation planning and has been applied by researchers and planners in thousands of organizations worldwide.
Establishing the ‘current accounts’ and building scenarios and evaluating the scenarios about criteria are the main WEAP applications in Simulation problems. | 1 | Applied and Interdisciplinary Chemistry |
In materials science, the Zener–Hollomon parameter, typically denoted as Z, is used to relate changes in temperature or strain-rate to the stress-strain behavior of a material. It has been most extensively applied to the forming of steels at increased temperature, when creep is active. It is given by
where is the strain rate, Q is the activation energy, R is the gas constant, and T is the temperature. The Zener–Hollomon parameter is also known as the temperature compensated strain rate, since the two are inversely proportional in the definition. It is named after Clarence Zener and John Herbert Hollomon, Jr. who established the formula based on the stress-strain behavior in steel.
When plastically deforming a material, the flow stress depends heavily on both the strain-rate and temperature. During forming processes, Z may help determine appropriate changes in strain-rate or temperature when the other variable is altered, in order to keep material flowing properly. Z has also been applied to some metals over a large range of strain rates and temperatures and shown comparable microstructures at the end-of-processing, as long as Z remained similar. This is because the relative activity of various deformation mechanisms is typically inversely proportional to temperature or strain-rate, such that decreasing strain rate or increasing temperature will increase Z and promote plastic deformation. | 1 | Applied and Interdisciplinary Chemistry |
Like many chiral molecules, the two stereoisomers of glyceraldehyde will gradually rotate the polarization direction of linearly polarized light as it passes through it, even in solution. The two stereoisomers are identified with the prefixes - and -, according to the sense of rotation: -glyceraldehyde is dextrorotatory (rotates the polarization axis clockwise), while -glyceraldehyde is levorotatory (rotates it counterclockwise).
The - and - prefixes are also used with other monosaccharides, to distinguish two particular stereoisomers that are mirror-images of each other. For this purpose, one considers the chiral carbon that is furthest removed from the C=O group. Its four bonds must connect to −H, −OH, −C(OH)H, and the rest of the molecule. If the molecule can be rotated in space so that the directions of those four groups match those of the analog groups in -glyceraldehyde's C2, then the isomer receives the - prefix. Otherwise, it receives the - prefix.
In the Fischer projection, the - and - prefixes specifies the configuration at the carbon atom that is second from bottom: - if the hydroxyl is on the right side, and - if it is on the left side.
Note that the - and - prefixes do not indicate the direction of rotation of polarized light, which is a combined effect of the arrangement at all chiral centers. However, the two enantiomers will always rotate the light in opposite directions, by the same amount. See also system. | 0 | Theoretical and Fundamental Chemistry |
The primary uses of lovastatin is for the treatment of dyslipidemia and the prevention of cardiovascular disease. It is recommended to be used only after other measures, such as diet, exercise, and weight reduction, have not improved cholesterol levels. | 0 | Theoretical and Fundamental Chemistry |
Early in his career as an independent researcher, Oesper continued investigations in analytical chemistry. His scientific accomplishments at this stage of his career included demonstrating the utility of the compound ferrous ethylene diamine sulfate in certain applications especially redox titrations. This compound replaced Mohrs salt (ferrous ammonium sulfate) in many applications because of its greater stability compared to Mohrs salt. He published these findings in 1947. Ferrous ethylene diamine sulfate is often referred to as "Oespers Salt", in recognition of Oespers scientific contributions.
A further contribution to analytical chemistry was his demonstration of the use of naphthidine as an indicator for certain chromate titrations such as for chloride ion. This improved indicator resulted in better testing results. He published this finding in 1934. | 1 | Applied and Interdisciplinary Chemistry |
Polycyclic aromatic hydrocarbons or graphenes—including fullerenes, carbon nanotubes, and graphite—have a hexagonal structure that is often described as chicken wire-like. | 0 | Theoretical and Fundamental Chemistry |
In inorganic extended solids, valence tautomerism can manifest itself in the change of oxidation states its spatial distribution upon the change of macroscopic thermodynamic conditions. Such effects have been called charge ordering or valence mixing to describe the behavior in inorganic oxides. | 0 | Theoretical and Fundamental Chemistry |
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