text stringlengths 105 4.57k | label int64 0 1 | label_text stringclasses 2 values |
|---|---|---|
N-linked glycans are extremely important in proper protein folding in eukaryotic cells. Chaperone proteins in the endoplasmic reticulum, such as calnexin and calreticulin, bind to the three glucose residues present on the core N-linked glycan. These chaperone proteins then serve to aid in the folding of the protein that the glycan is attached to. Following proper folding, the three glucose residues are removed, and the glycan moves on to further processing reactions. If the protein fails to fold properly, the three glucose residues are reattached, allowing the protein to re-associate with the chaperones. This cycle may repeat several times until a protein reaches its proper conformation. If a protein repeatedly fails to properly fold, it is excreted from the endoplasmic reticulum and degraded by cytoplasmic proteases.
N-linked glycans also contribute to protein folding by steric effects. For example, cysteine residues in the peptide may be temporarily blocked from forming disulfide bonds with other cysteine residues, due to the size of a nearby glycan. Therefore, the presence of a N-linked glycan allows the cell to control which cysteine residues will form disulfide bonds.
N-linked glycans also play an important role in cell-cell interactions. For example, tumour cells make N-linked glycans that are abnormal. These are recognized by the CD337 receptor on Natural Killer cells as a sign that the cell in question is cancerous.
Within the immune system the N-linked glycans on an immune cell's surface will help dictate that migration pattern of the cell, e.g. immune cells that migrate to the skin have specific glycosylations that favor homing to that site. The glycosylation patterns on the various immunoglobulins including IgE, IgM, IgD, IgE, IgA, and IgG bestow them with unique effector functions by altering their affinities for Fc and other immune receptors. Glycans may also be involved in "self" and "non self" discrimination, which may be relevant to the pathophysiology of various autoimmune diseases; including rheumatoid arthritis and type 1 diabetes.
The targeting of degradative lysosomal enzymes is also accomplished by N-linked glycans. The modification of an N-linked glycan with a mannose-6-phosphate residue serves as a signal that the protein to which this glycan is attached should be moved to the lysosome. This recognition and trafficking of lysosomal enzymes by the presence of mannose-6-phosphate is accomplished by two proteins: CI-MPR (cation-independent mannose-6-phosphate receptor) and CD-MPR (cation-dependent mannose-6-phosphate receptor). | 0 | Theoretical and Fundamental Chemistry |
In alkaline media oxygen evolution reactions, multiple adsorbent species (O, OH, OOH, and OO) and multiple steps are involved. Steps 4 and 5 often occur in a single step, but there is evidence that suggests steps 4 and 5 occur separately at pH 11 and higher.
Where the * indicate species adsorbed to the surface of the catalyst. | 0 | Theoretical and Fundamental Chemistry |
The generalized Woodward–Hoffmann rules, first given in 1969, are equivalent to an earlier general approach, the Möbius-Hückel concept of Zimmerman, which was first stated in 1966 and is also known as aromatic transition state theory. As its central tenet, aromatic transition state theory holds that allowed pericyclic reactions proceed via transition states with aromatic character, while forbidden pericyclic reactions would encounter transition states that are antiaromatic in nature. In the Dewar-Zimmerman analysis, one is concerned with the topology of the transition state of the pericyclic reaction. If the transition state involves 4n electrons, the Möbius topology is aromatic and the Hückel topology is antiaromatic, while if the transition state involves 4n + 2 electrons, the Hückel topology is aromatic and the Möbius topology is antiaromatic. The parity of the number of phase inversions (described in detail below) in the transition state determines its topology. A Möbius topology involves an odd number of phase inversions whereas a Hückel topology involves an even number of phase inversions.
In connection with Woodward–Hoffmann terminology, the number of antarafacial components and the number of phase inversions always have the same parity. Consequently, an odd number of antarafacial components gives Möbius topology, while an even number gives Hückel topology. Thus, to restate the results of aromatic transition state theory in the language of Woodward and Hoffmann, a 4n-electron reaction is thermally allowed if and only if it has an odd number of antarafacial components (i.e., Möbius topology); a (4n + 2)-electron reaction is thermally allowed if and only if it has an even number of antarafacial components (i.e., Hückel topology).
Procedure for Dewar-Zimmerman analysis (examples shown on the right): Step 1. Shade in all basis orbitals that are part of the pericyclic system. The shading can be arbitrary. In particular the shading does not need to reflect the phasing of the polyene MOs; each basis orbital simply need to have two oppositely phased lobes in the case of p or sp hybrid orbitals, or a single phase in the case of an s orbital. Step 2. Draw connections between the lobes of basis orbitals that are geometrically well-disposed to interact at the transition state. The connections to be made depend on the transition state topology. (For example, in the figure, different connections are shown in the cases of con- and disrotatory electrocyclization.) Step 3. Count the number of connections that occur between lobes of opposite shading: each of these connections constitutes a phase inversion. If the number of phase inversions is even, the transition state is Hückel, while if the number of phase inversions is odd, the transition state is Möbius. Step 4. Conclude that the pericyclic reaction is allowed if the electron count is 4n + 2 and the transition state is Hückel, or if the electron count is 4n and the transition state is Möbius; otherwise, conclude that the pericyclic reaction is forbidden.
Importantly, any scheme of assigning relative phases to the basis orbitals is acceptable, as inverting the phase of any single orbital adds 0 or ±2 phase inversions to the total, an even number, so that the parity of the number of inversions (number of inversions modulo 2) is unchanged. | 0 | Theoretical and Fundamental Chemistry |
Lithium tetramethylpiperidide (often abbreviated LiTMP or LTMP) is a chemical compound with the molecular formula . It is used as a non-nucleophilic base, being comparable to LiHMDS in terms of steric hindrance. | 0 | Theoretical and Fundamental Chemistry |
Defects in the erythropoietin receptor may produce erythroleukemia and familial erythrocytosis. Overproduction of red blood cells increases a chance of adverse cardiovascular event, such as thrombosis and stroke.
Rarely, seemingly beneficial mutations in the EpoR may arise, where increased red blood cell number allows for improved oxygen delivery in athletic endurance events with no apparent adverse effects upon the athlete's health (as for example in the Finnish athlete Eero Mäntyranta).
Erythropoietin was reported to maintain endothelial cells and to promote tumor angiogenesis, hence the dysregulation of EpoR may affect the growth of certain tumors. However this hypothesis is not universally accepted. | 1 | Applied and Interdisciplinary Chemistry |
VCl is a catalyst for the polymerization of alkenes, especially those useful in the rubber industry. The underlying technology is related to Ziegler–Natta catalysis, which involves the intermediacy of vanadium alkyls. | 0 | Theoretical and Fundamental Chemistry |
During the Dark Ages of the transition from bronze to iron, the decorative arts stood almost still but industrial metalwork was freely produced. There are a few remains of Geometric bronze vessels, but as in the case of the Early Minoan material, metal forms are recorded in their pottery derivatives. Some vase-shapes are clearly survivals from the Mycenaean repertory, but a greater number are new, and these are elementary and somewhat clumsy, spherical or biconical bodies, huge cylindrical necks with long band-handles and no spouts. Ceramic painted ornament also reflects originals of metal, and some scraps of thin bronze plate embossed with rows of knobs and lightly engraved in hatched or zig-zag outline doubtless represent the art which the newcomers brought with them to Greek lands. This kind of decorative work is better seen in bronzes of the closely related Villanova culture of north and central Italy. A novel feature is the application of small figures in the round, particularly birds and heads of oxen, as ornaments of handles, lids and rims. The Italian Geometric style developed towards complication, in crowded narrow bands of conventional patterns and serried rows of ducks; but contemporary Greek work was a refinement of the same crude elements.
Engraving appears at its best on the large catch-plates of fibulae, some of which bear the earliest known pictures of Hellenic mythology. Small statuettes of animals were made for votive use and also served as seals, the devices being cast underneath their bases. There is a large series of such figures, mostly horses, standing on engraved or perforated plates, which were evidently derived from seals; among the later examples are groups of men and centaurs. Pieces of tripod-cauldrons from Olympia have animals lying or standing on their upright ring-handles, which are steadied by human figures on the rims. Handles and legs are cast, and are enriched with graceful geometric mouldings. The bowls are wrought, and their shape and technique are pre-Hellenic. Here are two of the elements of classical Greek art in full course of development: the forms and processes of earlier times invigorated by a new aesthetic sense. | 1 | Applied and Interdisciplinary Chemistry |
Whereas the methods above describe various sequencing methods, separate related terms are used when a large portion of a genome is sequenced. Several platforms were developed to perform exome sequencing (a subset of all DNA across all chromosomes that encode genes) or whole genome sequencing (sequencing of the all nuclear DNA of a human). | 1 | Applied and Interdisciplinary Chemistry |
Landsupport (spelling: LANDSUPPORT) is a pilot consulting project funded by the European Union for land use for the near-natural modeling of different types and methods of land use while at the same time protecting the environment. | 1 | Applied and Interdisciplinary Chemistry |
Retinalophototrophs are found across all domains of life but predominantly in the Bacteria and Archaea taxonomic groups. Scientists believe retinalophototroph’s general ecological abundance correlates to horizontal gene transfer since only two genes are required for retinalophototrophy to occur: essentially, one gene for retinal-binding protein synthesis (bop) and one for retinal chromophore synthesis (blh). | 0 | Theoretical and Fundamental Chemistry |
The particle Reynolds number is important in determining the fall velocity of a particle. When the particle Reynolds number indicates laminar flow, Stokes' law can be used to calculate its fall velocity or settling velocity. When the particle Reynolds number indicates turbulent flow, a turbulent drag law must be constructed to model the appropriate settling velocity. | 1 | Applied and Interdisciplinary Chemistry |
Isethionates are esters of long-chain aliphatic carboxylic acids (C – C) with isethionic acid (2-hydroxyethanesulfonic acid) or salts thereof, such as ammonium isethionate or sodium isethionate. They are also referred to as acyl isethionates or acyloxyethanesulfonates.
Like the taurides, isethionates are a class of particularly mild anionic surfactants which, unlike ordinary soaps, retain their washing-active properties even in hard water. Isethionates are obtained on an industrial scale reacting mixtures of carboxylic acids with salts of isethionic acid under acidic catalysis e. g. with methanesulfonic acid. The mixtures of carboxylic acids are obtained from the hydrolysis of animal fats (tallow) or vegetable oils, preferably coconut oil, but also palm oil, soybean oil or castor oil.
Isethionates are solids which are often mixed with fatty acids (up to 30% by weight) to lower their freezing point. Despite its low water solubility (100ppm at 25 °C), the lower-priced sodium cocoylisethionate has found more widespread use than its well water-soluble ammonium salt (> 25 wt.% at 25 °C). To solubilize the sparsely soluble isethionates and taurides, the formation of mixtures with amphoteric surfactants (such as cocamidopropyl betaine) are proposed. From such mixtures, it is possible to prepare liquid, clear and transparent aqueous concentrates which are liquid at room temperature.
Isethionates are characterized by excellent skin compatibility, excellent foaming (even in hard water), good cleansing properties and a pleasant skin feel. They are non-toxic and readily biodegradable. However, in contrast to the taurides, they are not long-term stable outside a pH range of 5 to 8. Isethionates are used in solid soaps (so-called syndet bars) and in other personal care products such as lotions, washing and shower gels, shampoos, liquid soaps, shaving creams, and other cosmetic and dermatological preparations. | 0 | Theoretical and Fundamental Chemistry |
The types of printers used for organ printing include:
* Inkjet printer
* Multi-nozzle
* Hybrid printer
* Electrospinning
* Drop-on-demand
These printers are used in the methods described previously. Each printer requires different materials and has its own advantages and limitations. | 1 | Applied and Interdisciplinary Chemistry |
The term "plastic scintillator" typically refers to a scintillating material in which the primary fluorescent emitter, called a fluor, is suspended in the base, a solid polymer matrix. While this combination is typically accomplished through the dissolution of the fluor prior to bulk polymerization, the fluor is sometimes associated with the polymer directly, either covalently or through coordination, as is the case with many Li6 plastic scintillators. Polyethylene naphthalate has been found to exhibit scintillation by itself without any additives and is expected to replace existing plastic scintillators due to higher performance and lower price. The advantages of plastic scintillators include fairly high light output and a relatively quick signal, with a decay time of 2–4 nanoseconds, but perhaps the biggest advantage of plastic scintillators is their ability to be shaped, through the use of molds or other means, into almost any desired form with what is often a high degree of durability. Plastic scintillators are known to show light output saturation when the energy density is large (Birks' Law). | 0 | Theoretical and Fundamental Chemistry |
The first experiments indicating that some plants do not use carbon fixation but instead produce malate and aspartate in the first step of carbon fixation were done in the 1950s and early 1960s by Hugo Peter Kortschak and Yuri Karpilov. The pathway was elucidated by Marshall Davidson Hatch and Charles Roger Slack, in Australia, in 1966. While Hatch and Slack originally referred to the pathway as the "C dicarboxylic acid pathway", it is sometimes called the Hatch–Slack pathway. | 0 | Theoretical and Fundamental Chemistry |
Time-domain diffuse optics or time-resolved functional near-infrared spectroscopy is a branch of functional near-Infrared spectroscopy which deals with light propagation in diffusive media. There are three main approaches to diffuse optics namely continuous wave (CW), frequency domain (FD) and time-domain (TD). Biological tissue in the range of red to near-infrared wavelengths are transparent to light and can be used to probe deep layers of the tissue thus enabling various in vivo applications and clinical trials. | 0 | Theoretical and Fundamental Chemistry |
In stereochemistry, topicity is the stereochemical relationship between substituents and the structure to which they are attached. Depending on the relationship, such groups can be heterotopic, homotopic, enantiotopic, or diastereotopic. | 0 | Theoretical and Fundamental Chemistry |
The IIR publishes two professional Directories: a [https://iifiir.org/en/directory/laboratories Laboratory Directory], which lists more than 300 laboratories in 55 countries; an [https://iifiir.org/en/directory/experts Expertise Directory], which lists over 300 international experts in the refrigeration sector. | 0 | Theoretical and Fundamental Chemistry |
* Gas chromatography/mass spectrometry-olfactometry (GC/MS-O)
* GC-recomposition-olfactometry (GC-R)
* Multi-gas chromatography-olfactometry | 0 | Theoretical and Fundamental Chemistry |
If a spectrum of an unknown chemical compound is available, a reverse search can be carried out by entering the values of the chemical shift, frequency or mass of the peaks in the NMR, FT-IR or EI-MS spectrum respectively. This type of search affords all the chemical compounds in the database that have the entered spectral characteristics. | 0 | Theoretical and Fundamental Chemistry |
In the history of science, the principle of maximum work was a postulate concerning the relationship between chemical reactions, heat evolution, and the potential work produced there from. The principle was developed in approximate form in 1875 by French chemist Marcellin Berthelot, in the field of thermochemistry, and then in 1876 by American mathematical physicist Willard Gibbs, in the field of thermodynamics, in a more accurate form. Berthelot's version was essentially: "every pure chemical reaction is accompanied by evolution of heat." (and that this yields the maximum amount of work). The effects of irreversibility, however, showed this version to be incorrect. This was rectified, in thermodynamics, by incorporating the concept of entropy. | 0 | Theoretical and Fundamental Chemistry |
The SK channel family contains 4 members – SK1, SK2, SK3, and SK4. SK4 is often referred to as IK (Intermediate conductance) due to its higher conductance 20 – 80 pS. | 1 | Applied and Interdisciplinary Chemistry |
In laboratory experiments, activation of cannabinoid receptors had an effect on the activation of GTPases in macrophages, neutrophils, and bone marrow cells. These receptors have also been implicated in the migration of B cells into the marginal zone and the regulation of IgM levels. | 1 | Applied and Interdisciplinary Chemistry |
For light, as in other settings, the scattering cross section for particles is generally different from the geometrical cross section of the particle, and it depends upon the wavelength of light and the permittivity, shape, and size of the particle. The total amount of scattering in a sparse medium is proportional to the product of the scattering cross section and the number of particles present.
In the interaction of light with particles, many processes occur, each with their own cross sections, including absorption, scattering, and photoluminescence. The sum of the absorption and scattering cross sections is sometimes referred to as the attenuation or extinction cross section.
The total extinction cross section is related to the attenuation of the light intensity through the Beer–Lambert law, which says that attenuation is proportional to particle concentration:
where is the attenuation at a given wavelength , is the particle concentration as a number density, and is the path length. The absorbance of the radiation is the logarithm (decadic or, more usually, natural) of the reciprocal of the transmittance :
Combining the scattering and absorption cross sections in this manner is often necessitated by the inability to distinguish them experimentally, and much research effort has been put into developing models that allow them to be distinguished, the Kubelka-Munk theory being one of the most important in this area. | 0 | Theoretical and Fundamental Chemistry |
False brinelling is a bearing damage caused by fretting, with or without corrosion, that causes imprints that look similar to brinelling, but are caused by a different mechanism. False brinelling may occur in bearings which act under small oscillations or vibrations.
The basic cause of false brinelling is that the design of the bearing does not have a method for redistribution of lubricant without large rotational movement of all bearing surfaces in the raceway. Lubricant is pushed out of a loaded region during small oscillatory movements and vibration where the bearings surfaces repeatedly do not move very far. Without lubricant, wear is increased when the small oscillatory movements occur again. It is possible for the resulting wear debris to oxidize and form an abrasive compound which further accelerates wear. | 1 | Applied and Interdisciplinary Chemistry |
When Davy's lecture series on Galvanism ended, he progressed to a new series on agricultural chemistry, and his popularity continued to skyrocket. By June 1802, after just over a year at the Institution and at the age of 23, Davy was nominated to full lecturer at the Royal Institution of Great Britain. Garnett quietly resigned, citing health reasons. | 1 | Applied and Interdisciplinary Chemistry |
There are three classes of multiple sclerosis: relapsing-remitting (RRMS), primary progressive (PPMS) and secondary progressive (SPMS). Gene regulatory network (GRN) plays a vital role to understand the disease mechanism across these three different multiple sclerosis classes. | 1 | Applied and Interdisciplinary Chemistry |
The precursors of ketone bodies include fatty acids from adipose tissue or the diet and ketogenic amino acids. The formation of ketone bodies occurs via ketogenesis in the mitochondrial matrix of liver cells.
Fatty acids can be released from adipose tissue by adipokine signaling of high glucagon and epinephrine levels and low insulin levels. High glucagon and low insulin correspond to times of low glucose availability such as fasting. Fatty acids bound to coenzyme A allow penetration into mitochondria. Once inside the mitochondrion, the bound fatty acids are used as fuel in cells predominantly through beta oxidation, which cleaves two carbons from the acyl-CoA molecule in every cycle to form acetyl-CoA. Acetyl-CoA enters the citric acid cycle, where it undergoes an aldol condensation with oxaloacetate to form citric acid; citric acid then enters the tricarboxylic acid cycle (TCA), which harvests a very high energy yield per carbon in the original fatty acid.
Acetyl-CoA can be metabolized through the TCA cycle in any cell, but it can also undergo ketogenesis in the mitochondria of liver cells. When glucose availability is low, oxaloacetate is diverted away from the TCA cycle and is instead used to produce glucose via gluconeogenesis. This utilization of oxaloacetate in gluconeogenesis can make it unavailable to condense with acetyl-CoA, preventing entrance into the TCA cycle. In this scenario, energy can be harvested from acetyl-CoA through ketone production.
In ketogenesis, two acetyl-CoA molecules condense to form acetoacetyl-CoA via thiolase. Acetoacetyl-CoA briefly combines with another acetyl-CoA via HMG-CoA synthase to form hydroxy-β-methylglutaryl-CoA. Hydroxy-β-methylglutaryl-CoA form the ketone body acetoacetate via HMG-CoA lyase. Acetoacetate can then reversibly convert to another ketone body—D-β-hydroxybutyrate—via D-β-hydroxybutyrate dehydrogenase. Alternatively, acetoacetate can spontaneously degrade to a third ketone body (acetone) and carbon dioxide, which generates much greater concentrations of acetoacetate and D-β-hydroxybutyrate. The resulting ketone bodies cannot be used for energy by the liver so are exported from the liver to supply energy to the brain and peripheral tissues.
In addition to fatty acids, deaminated ketogenic amino acids can also be converted into intermediates in the citric acid cycle and produce ketone bodies. | 1 | Applied and Interdisciplinary Chemistry |
Viral genes are expressed through the use of the host cells replication machinery; therefore, many viral genes have promoters that support binding of many transcription factors found naturally in the host cells. These transcription factors along with the virus own proteins can repress or activate genes from both the virus and the host cells genome. Many viruses can also increase the production of the cells regulatory proteins. | 1 | Applied and Interdisciplinary Chemistry |
Another factor affecting the availability of metal ions was their solubilities with HS. Hydrogen sulfide was abundant in the early sea giving rise to HS in the prebiotic acidic conditions and HS in the neutral (pH = 7.0) conditions. In the series of metal sulfides, insolubility increases at neutral pH following the Irving–Williams series:
* Mn(II) < Fe(II) < Co(II) ≤ Ni(II) < Cu(II) > Zn(II)
So in high amounts of HS, which was the prebiotic condition, only Fe was most prominently available in its ionic form due to its low insolubility with sulfides. The increasing oxidation of HS into SO leads to the later release of Co, Ni, Cu, and Zn since all of their sulfates are soluble. | 0 | Theoretical and Fundamental Chemistry |
Yves Jeannin studied at the École Nationale Supérieure de Chimie de Paris (Engineer in 1954, graduation rank: first). His first job was at the IRSID for a sixteen-month stay in London at the Royal School of Mines with Prof. F.D. Richardson. He worked on the thermodynamics of the oxidation of iron-chromium alloys. He is preparing a PhD thesis in Physical Sciences (1962) under the supervision of Pr J. Bénard, on the crystallochemistry of titanium sulphides. In 1963, he spent a period in the United States as a Post-doctoral Research Associate of the United States Atomic Energy Commission, Argonne National Laboratory, and Iowa State University.
He became a lecturer at the Paul Sabatier University of Toulouse in 1964, then Professor at the Pierre and Marie Curie University, Paris (UPMC), in 1974 where he taught in preparation for the medical school entrance examination at the Pitié-Salpétrière Hospital, in inorganic chemistry, the Master of Chemistry at UPMC, the Master of Chemistry at LÉcole Normale Supérieure, the Advanced Study Diploma (DEA) in inorganic chemistry, the DEA in crystallography, the preparation for the agrégation in chemistry at LÉcole Normale Supérieure.
Jeannin became head of the Chemistry group of the Lagarrigue Commission in charge of rebuilding the chemistry curricula of high schools (1976-1980). He was a member of the jury for the agrégation examination in chemistry (1971-1974), a member of the jury for admission to the École Normale Supérieure (9 years), and a member of the jury for admission to the École Polytechnique (2 years). At the request of the Ministry, he took part in the setting up of the internal agrégation in Physical Sciences (President of the jury, 1985-1988). He is a member of the Commission proposing to the Minister the General Inspectors, member of the recruitment jury of the Engineers of the Corps of Mines. He will also be a chargé de mission at the French Ministry of Research (4 years).
Jeannin is a member of the University's Scientific Council, President of the Research Commission of the UFR of Chemistry, and a member of the Academic Council of the École Normale Supérieure. | 0 | Theoretical and Fundamental Chemistry |
Biofluid Dynamics refers to the study of fluid Dynamics of basic biological fluids such as blood, air etc. and has immense applications in the field of diagnosing, treating and certain surgical procedures related to the disorders/diseases which originate in the body relating to cardiovascular, pulmonary, synovial systems etc.
The different types of cardiovascular diseases include Aneurysms, Angina, Atherosclerosis, Stroke, Different types of Cerebrovascular disease, Heart Failure, Coronary Heart diseases and Myocardial infarction or Heart attacks.
The Computational Fluid dynamics (CFD) models prepared through software, of the arteries, veins etc. not only lead to the identification of properties of flowing blood inside arteries but also changes in viscosity can be identified which may be the result of certain underlying disease/disorder. Moreover, the stress concentration and the distribution of stresses in different biological systems carrying fluids can also be identified. This has led to a greater degree of assistance to biomedical engineers in recognizing the cause of certain diseases and thus they can easily search for the method of cure for that disease/disorder. Also, this has led to a greater degree of good research in the fields of biotechnology, Bio-Mechanics etc. | 1 | Applied and Interdisciplinary Chemistry |
Methane (CH) in the Earth's atmosphere is a powerful greenhouse gas with a global warming potential (GWP) 84 times greater than CO over a 20-year time frame. Methane is not as persistent as CO, and tails off to about 28 times greater than CO over a 100-year time frame.
Radiative or climate forcing is the scientific concept used to measure the human impact on the environment in watts per square meter (W/m). It refers to the "difference between solar irradiance absorbed by the Earth and energy radiated back to space" The direct radiative greenhouse gas forcing effect of methane relative to the year 1750 was estimated at 0.5 W/m in the 2007 IPCC "Climate Change Synthesis Report 2007".
In their May 21, 2021 173-page "Global Methane Assessment", the UNEP and CCAP said that their "understanding of methane's effect on radiative forcing" improved with research by teams led by M. Etminan in 2016, and William Collins in 2018, which resulted in an "upward revision" since the 2014 IPCC Fifth Assessment Report (AR5). The "improved understanding" says that prior estimates of the "overall societal impact of methane emissions" were likely underestimated.
Etminan et al. published their new calculations for methane's radiative forcing (RF) in a 2016 Geophysical Research Letters journal article which incorporated the shortwave bands of CH in measuring forcing, not used in previous, simpler IPCC methods. Their new RF calculations which significantly revised those cited in earlier, successive IPCC reports for well mixed greenhouse gases (WMGHG) forcings by including the shortwave forcing component due to CH, resulted in estimates that were approximately 20–25% higher. Collins et al. said that CH mitigation that reduces atmospheric methane by the end of the century, could "make a substantial difference to the feasibility of achieving the Paris climate targets", and would provide us with more "allowable carbon emissions to 2100".
In addition to the direct heating effect and the normal feedbacks, the methane breaks down to carbon dioxide and water. This water is often above the tropopause, where little water usually reaches. Ramanathan (1998) notes that both water and ice clouds, when formed at cold lower stratospheric temperatures, are extremely efficient in enhancing the atmospheric greenhouse effect. He also notes that there is a distinct possibility that large increases in methane in future may lead to a surface warming that increases nonlinearly with the methane concentration.
Mitigation efforts to reduce short-lived climate pollutants like methane and black carbon would help combat "near-term climate change" and would support Sustainable Development Goals. | 1 | Applied and Interdisciplinary Chemistry |
A phosphoramidite (RO)PNR is a monoamide of a phosphite diester. The key feature of phosphoramidites is their markedly high reactivity towards nucleophiles catalyzed by weak acids e.c., triethylammonium chloride or 1H-tetrazole. In these reactions, the incoming nucleophile replaces the NR moiety. | 0 | Theoretical and Fundamental Chemistry |
Spiral separators of the wet type, also called spiral concentrators, are devices to separate solid components in a slurry, based upon a combination of the solid particle density as well as the particle's hydrodynamic properties (e.g. drag). The device consists of a tower, around which is wound a sluice, from which slots or channels are placed in the base of the sluice to extract solid particles that have come out of suspension.
As larger and heavier particles sink to the bottom of the sluice faster and experience more drag from the bottom, they travel slower, and so move towards the center of the spiral. Conversely, light particles stay towards the outside of the spiral, with the water, and quickly reach the bottom. At the bottom, a "cut" is made with a set of adjustable bars, channels, or slots, separating the low and high density parts. | 0 | Theoretical and Fundamental Chemistry |
In 2023, the Oregon Department of Environmental Quality (DEQ) and Oregon Health Authority issued a cyanobacteria advisory for much of the Willamette River as it runs through Portland. The advisory affected the Willamette from the Ross Island Lagoon through Cathedral Park. Testing by the DEQ showed microcystin levels at 549 ppb. | 1 | Applied and Interdisciplinary Chemistry |
Noel Kingsbury writes:
"That private companies could be so effective in breeding cereal grains indicated that there was no link of necessity between their improvement and the publicly funded research that was to so dominate this sector over so much of the next century."
In 1903 Professor Willet M. Hays (1859–1927) of the Agricultural Experiment Station in Minnesota, USA said No one has done more brilliant work in Agricultural Plant Breeding than Messrs. Garton, and this is from now on to be recognised. | 1 | Applied and Interdisciplinary Chemistry |
Exciplexes provide one of the three dynamic mechanisms by which fluorescence is quenched. A regular exciplex has some charge-transfer (CT) character, and in the extreme case there are distinct radical ions with unpaired electrons. If the unpaired electrons can spin-pair to form a covalent bond, then the covalent bonding interaction can lower the energy of the charge transfer state. Strong CT stabilisation has been shown to lead to a conical intersection of this exciplex state with the ground state in a balance of steric effects, electrostatic interactions, stacking interactions, and relative conformations that can determine the formation and accessibility of bonded exciplexes.
As an exception to the conventional radical ion pair model, this mode of covalent bond formation is of interest to photochemistry research, as well as the many biological fields using fluorescence spectroscopy techniques. Evidence for the bonded exciplex intermediate has been given in studies of steric and Coulombic effects on the quenching rate constants and from extensive density functional theory computations that show a curve crossing between the ground state and the low-energy bonded exciplex state. | 0 | Theoretical and Fundamental Chemistry |
P680 is the strongest biological oxidizing agent known, with an estimated redox potential of ~1.3 V. This makes it possible to oxidize water during oxygenic photosynthesis. P680 recovers its lost electron by oxidizing water via the oxygen-evolving complex, which regenerates P680. | 0 | Theoretical and Fundamental Chemistry |
Although telomeres shorten during the lifetime of an individual, it is telomere shortening-rate rather than telomere length that is associated with the lifespan of a species. Critically short telomeres trigger a DNA damage response and cellular senescence. Mice have much longer telomeres, but a greatly accelerated telomere shortening-rate and greatly reduced lifespan compared to humans and elephants.
Telomere shortening is associated with aging, mortality, and aging-related diseases in experimental animals. Although many factors can affect human lifespan, such as smoking, diet, and exercise, as persons approach the upper limit of human life expectancy, longer telomeres may be associated with lifespan. | 1 | Applied and Interdisciplinary Chemistry |
In photosynthetic bacteria, the proteins that gather light for photosynthesis are embedded in cell membranes. In its simplest form, this involves the membrane surrounding the cell itself. However, the membrane may be tightly folded into cylindrical sheets called thylakoids, or bunched up into round vesicles called intracytoplasmic membranes. These structures can fill most of the interior of a cell, giving the membrane a very large surface area and therefore increasing the amount of light that the bacteria can absorb.
In plants and algae, photosynthesis takes place in organelles called chloroplasts. A typical plant cell contains about 10 to 100 chloroplasts. The chloroplast is enclosed by a membrane. This membrane is composed of a phospholipid inner membrane, a phospholipid outer membrane, and an intermembrane space. Enclosed by the membrane is an aqueous fluid called the stroma. Embedded within the stroma are stacks of thylakoids (grana), which are the site of photosynthesis. The thylakoids appear as flattened disks. The thylakoid itself is enclosed by the thylakoid membrane, and within the enclosed volume is a lumen or thylakoid space. Embedded in the thylakoid membrane are integral and peripheral membrane protein complexes of the photosynthetic system.
Plants absorb light primarily using the pigment chlorophyll. The green part of the light spectrum is not absorbed but is reflected which is the reason that most plants have a green color. Besides chlorophyll, plants also use pigments such as carotenes and xanthophylls. Algae also use chlorophyll, but various other pigments are present, such as phycocyanin, carotenes, and xanthophylls in green algae, phycoerythrin in red algae (rhodophytes) and fucoxanthin in brown algae and diatoms resulting in a wide variety of colors.
These pigments are embedded in plants and algae in complexes called antenna proteins. In such proteins, the pigments are arranged to work together. Such a combination of proteins is also called a light-harvesting complex.
Although all cells in the green parts of a plant have chloroplasts, the majority of those are found in specially adapted structures called leaves. Certain species adapted to conditions of strong sunlight and aridity, such as many Euphorbia and cactus species, have their main photosynthetic organs in their stems. The cells in the interior tissues of a leaf, called the mesophyll, can contain between 450,000 and 800,000 chloroplasts for every square millimeter of leaf. The surface of the leaf is coated with a water-resistant waxy cuticle that protects the leaf from excessive evaporation of water and decreases the absorption of ultraviolet or blue light to minimize heating. The transparent epidermis layer allows light to pass through to the palisade mesophyll cells where most of the photosynthesis takes place. | 0 | Theoretical and Fundamental Chemistry |
This method required the introduction of a very small volume of concentrated tracer at the inlet of the reactor, such that it approaches the Dirac delta function. Although an infinitely short injection cannot be produced, it can be made much smaller than the mean residence time of the vessel. If a mass of tracer, , is introduced into a vessel of volume and an expected residence
time of , the resulting curve of can be transformed into a dimensionless residence time distribution curve by the following relation: | 0 | Theoretical and Fundamental Chemistry |
The first event appears to be the accumulation of cell adhesion molecules such as NF186 or NrCAM. The intra-cellular regions of these cell-adhesion molecules interact with ankyrin G, which serves as an anchor for sodium channels. At the same time, the periaxonal extension of the glial cell wraps around the axon, giving rise to the paranodal regions. This movement along the axon contributes significantly to the overall formation of the nodes of Ranvier by permitting heminodes formed at the edges of neighboring glial cells to fuse into complete nodes.
Septate-like junctions form at the paranodes with the enrichment of NF155 in glial paranodal loops. Immediately following the early differentiation of the nodal and paranodal regions, potassium channels, Caspr2 and TAG1 accumulate in the juxta-paranodal regions. This accumulation coincides directly with the formation of compact myelin. In mature nodal regions, interactions with the intracellular proteins appear vital for the stability of all nodal regions. In the CNS, oligodendrocytes do not possess microvilli, but appear capable to initiate the clustering of some axonal proteins through secreted factors. The combined effects of such factors with the subsequent movements generated by the wrapping of oligodendrocyte periaxonal extension could account for the organization of CNS nodes of Ranvier. | 1 | Applied and Interdisciplinary Chemistry |
The following genes are analogous or homologous between Drosophila melanogaster (in bold) and human TNFR1 signalling:
* Imd: human orthologue = RIP1
* Tak1: human orthologue = Tak1
* TAB2: human orthologue = TAB2
* Dredd: human orthologue = caspase-8
* FADD: human orthologue = FADD
* Key/Ikkγ: human orthologue = NEMO
* Ird5: human orthologue = IKK2
* Relish: human orthologues = p65/p50 and IκB
* Iap2: human orthologue = cIAP2
* UEV1a: human orthologue = UEV1a
* bend: human orthologue = UBC13 | 1 | Applied and Interdisciplinary Chemistry |
Enolate ions are more useful than enols for two reasons. First, pure enols can't normally be isolated but are instead generated only as short lived intermediates in low concentration. By contrast, stable solutions of pure enolate ions
are easily prepared from most carbonyl compounds by reaction with a strong base. Second, enolate ions are more reactive than enols and undergo many reactions that enols don't. Whereas enols are neutral, enolate ions are negatively charged, making them much better nucleophiles. As a result, enolate ions are more common than enols in both laboratory and biological chemistry.
Because they are resonance hybrids of two nonequivalent forms, enolate ions can be looked at either as vinylic alkoxides (C=C- O) or as α-ketocarbanions (C-C= O). Thus, enolate ions can react with electrophiles either on oxygen or on carbon. Reaction on oxygen yields an enol derivative, while reaction on carbon yields an α-substituted carbonyl compound. Both kinds of reactivity are known, but reaction on carbon is more common. | 0 | Theoretical and Fundamental Chemistry |
The top 1% students from this examination are selected to sit for the Indian National Chemistry Olympiad. The theory part of the examination is held in the last week of January. The top 30 among all students are selected for the Orientation-Cum-Selection-Camp (OCSC), Chemistry. | 1 | Applied and Interdisciplinary Chemistry |
The cathode layer begins with the Aston dark space, and ends with the negative glow region. The cathode layer shortens with increased gas pressure. The cathode layer has a positive space charge and a strong electric field. | 0 | Theoretical and Fundamental Chemistry |
Researchers are trying to improve the efficiency and are focusing on use of radioactive C, which is a minor contributor to the radioactivity of nuclear waste.
C undergoes beta decay, in which it emits a low-energy beta particle to become Nitrogen-14, which is stable (not radioactive).
These beta particles, having an average energy of 50 keV, undergo inelastic collisions with other carbon atoms, thus creating electron-hole pairs which then contribute to an electric current. This can be restated in terms of band theory by saying that due to the high energy of the beta particles, electrons in the carbon valence band jump to its conduction band, leaving behind holes in the valence band where electrons were earlier present. | 0 | Theoretical and Fundamental Chemistry |
Chiral column chromatography is a variant of column chromatography that is employed for the separation of chiral compounds, i.e. enantiomers, in mixtures such as racemates or related compounds. The chiral stationary phase (CSP) is made of a support, usually silica based, on which a chiral reagent or a macromolecule with numerous chiral centers is bonded or immobilized.
The chiral stationary phase can be prepared by attaching a chiral compound to the surface of an achiral support such as silica gel. For example, one class of the most commonly used chiral stationary phases both in liquid chromatography and supercritical fluid chromatography is based on oligosaccharides such as Amylose Cellulose or Cyclodextrin (in particular with β-cyclodextrin, a seven sugar ring molecule) immobilized on silica gel.
The principle can be also applied to the fabrication of Monolithic HPLC columns or Gas Chromatography columns. or Supercritical Fluid Chromatography columns. | 0 | Theoretical and Fundamental Chemistry |
The APE(X)C, or All Purpose Electronic (X) Computer series was designed by Andrew Donald Booth at Birkbeck College, London in the early 1950s. His work on the APE(X)C series was sponsored by the British Rayon Research Association. Although the naming conventions are slightly unclear, it seems the first model belonged to the BRRA. According to Booth, the X stood for X-company.
One of the series was also known as the APE(X)C or All Purpose Electronic X-Ray Computer and was sited at Birkbeck. | 0 | Theoretical and Fundamental Chemistry |
Sulfate transported through the roots and SO diffusing into leaves becomes the pool for plants to assimilate sulfur throughout their tissues. Though there is minimal fractionation from the source sulfur of the total plant organic matter, in wheat, roots and stems are depleted from soil by 2‰ and leaves and grain are 2‰ enriched. The S enrichment in leaf whole matter is not caused by S-enriched sulfate present in the leaf, but is the result of the S-enrichment arriving at sink organs causing proteins in the leaves to be S-enriched. In rice, translocation from root to shoot does not discriminate S isotopes, however, the sulfate pools of the shoot are significantly S-enriched with respect to the sulfate pools of both root and sap. As sulfate moves through the plant system and is incorporated into biomass, the pool becomes enriched, giving organs such as leaves and grains higher δS values than earlier tissues. | 0 | Theoretical and Fundamental Chemistry |
Clinical trials designed by a local investigator, and (in the US) federally funded clinical trials, are almost always administered by the researcher who designed the study and applied for the grant. Small-scale device studies may be administered by the sponsoring company. Clinical trials of new drugs are usually administered by a contract research organization (CRO) hired by the sponsoring company. The sponsor provides the drug and medical oversight. A CRO is contracted to perform all the administrative work on a clinical trial. For PhasesII–IV the CRO recruits participating researchers, trains them, provides them with supplies, coordinates study administration and data collection, sets up meetings, monitors the sites for compliance with the clinical protocol, and ensures the sponsor receives data from every site. Specialist site management organizations can also be hired to coordinate with the CRO to ensure rapid IRB/IEC approval and faster site initiation and patient recruitment. PhaseI clinical trials of new medicines are often conducted in a specialist clinical trial clinic, with dedicated pharmacologists, where the subjects can be observed by full-time staff. These clinics are often run by a CRO which specialises in these studies.
At a participating site, one or more research assistants (often nurses) do most of the work in conducting the clinical trial. The research assistant's job can include some or all of the following: providing the local institutional review board (IRB) with the documentation necessary to obtain its permission to conduct the study, assisting with study start-up, identifying eligible patients, obtaining consent from them or their families, administering study treatment(s), collecting and statistically analyzing data, maintaining and updating data files during followup, and communicating with the IRB, as well as the sponsor and CRO. | 1 | Applied and Interdisciplinary Chemistry |
Support for the Bulletin de la Société Chimique de Paris began in 1858.
In the 21st century, the society has become a member of European Chemical Society, which is an organization of 16 European chemical societies. This European consortium was established in the late 1990s as many chemical journals owned by national chemical societies were amalgamated. In 2010 they started ChemistryViews.org, their news and information service for chemists and other scientists worldwide. | 1 | Applied and Interdisciplinary Chemistry |
Dr. R.U. Lemieux received numerous awards and honours for his work in chemistry:
* Induction into the Royal Society of Canada (1954)
* C.S. Hudson Award of the American Chemical Society (1966)
* Became the first western Canadian to be elected a fellow of the Royal Society (England) (1967)
* Appointed Officer of the Order of Canada (1968)
* Haworth Award and Medal (1983)
* The Tishler Award, Harvard University (1983)
* Gairdner Foundation International Award (1985)
* Made Honorary Doctor of Philosophy from the University of Stockholm (1988)
* Induction into the Alberta Order of Excellence (1990)
* King Faisal International Prize for Science (first Canadian) (1990)
* NSERC Gold Medal in Science (1991)
* Albert Einstein World Award of Science (1992)
* Made Companion of the Order of Canada (1994)
* Wolf Prize in Chemistry (1999) | 0 | Theoretical and Fundamental Chemistry |
Researchers claim experiments that successfully detected the Sokolov–Ternov effect may also detect the Unruh effect under certain conditions.
Theoretical work in 2011 suggests that accelerating detectors could be used for the direct detection of the Unruh effect with current technology.
The Unruh effect may have been observed for the first time in 2019 in the high energy channeling radiation explored by the NA63 experiment at CERN. | 0 | Theoretical and Fundamental Chemistry |
Inflammation is the bodys response to foreign objects, irritants, germs, and even pathogens. Although such a response is standard in some cases, if left untreated, chronic inflammation can lead to muscle degeneration, gastrointestinal disorders, and some types of cancers. While most treatments, such as anti-inflammatory drugs and steroid injections, can help relieve symptoms, they often fail to address the conditions underlying cause. Therefore, researchers have sought to explore new and innovative ways of inflammation treatment, such as chemotactic drug delivery.
One promising drug delivery system was based on engineered neutrophils that targeted inflammation sites through chemotaxis's unique properties. This approach took advantage of the concentration difference between iNOS and ROS for inflammatory disease sites and normal tissues. By doing so, this drug delivery system provides the possibility to target areas of inflammation, increase drug efficacy, and minimize damage to the surrounding tissue. Moreover, because this concentration gradient is ubiquitous in the microenvironment of inflammatory diseases, common drug-targeting limitations such as individual differences can be avoided. Another example of an innovative drug delivery system that uses the property of chemotaxis is leukocytes. Indeed, during inflammation, the molecules on a cell that allows for adhesion are overly produced. With this unique condition, researchers can modify leukocytes to quickly detect the cell, attach itself to the surface, and deliver a therapeutic payload. Overall, many promising therapies and drug delivery systems are being developed to target inflammation more effectively. Chemotactic drug delivery systems are just one of many promising avenues that seek to increase target sites specifically, decreasing the needed drug dosage, reducing toxicity, and increasing drug efficacy. | 1 | Applied and Interdisciplinary Chemistry |
In 1903, Hermann Emil Fischer and Joseph von Mering disclosed their discovery that diethylbarbituric acid, formed from the reaction of acid, phosphorus oxychloride and urea, induces sleep in dogs. The discovery was patented and licensed to Bayer pharmaceuticals, which marketed the compound under the trade name Veronal as a sleep aid beginning in 1904. Systematic investigations of the effect of structural changes on potency and duration of action led to the discovery of phenobarbital at Bayer in 1911 and the discovery of its potent anti-epileptic activity in 1912. Phenobarbital was among the most widely used drugs for the treatment of epilepsy through the 1970s, and as of 2014, remains on the World Health Organizations list of essential medications. The 1950s and 1960s saw increased awareness of the addictive properties and abuse potential of barbiturates and amphetamines and led to increasing restrictions on their use and growing government oversight of prescribers. Today, amphetamine is largely restricted to use in the treatment of attention deficit disorder and phenobarbital in the treatment of epilepsy.
In 1958, Leo Sternbach discovered the first benzodiazepine, chlordiazepoxide (Librium). Dozens of other benzodiazepines have been developed and are in use, some of the more popular drugs being diazepam (Valium), alprazolam (Xanax), clonazepam (Klonopin), and lorazepam (Ativan). Due to their far superior safety and therapeutic properties, benzodiazepines have largely replaced the use of barbiturates in medicine, except in certain special cases. When it was later discovered that benzodiazepines, like barbiturates, significantly lose their effectiveness and can have serious side effects when taken long-term, Heather Ashton researched benzodiazepine dependence and developed a protocol to discontinue their use. | 1 | Applied and Interdisciplinary Chemistry |
Under Japanese law, levetiracetam and other racetams cannot be brought into the country except for personal use by a traveler for whom it has been prescribed. Travelers who plan to bring more than a month's worth must apply for an import certificate, known as a . | 0 | Theoretical and Fundamental Chemistry |
Relativistic fluid dynamics studies the macroscopic and microscopic fluid motion at large velocities comparable to the velocity of light. This branch of fluid dynamics accounts for the relativistic effects both from the special theory of relativity and the general theory of relativity. The governing equations are derived in Riemannian geometry for Minkowski spacetime. | 1 | Applied and Interdisciplinary Chemistry |
The disaster prompted many countries to introduce tougher rules for the testing and licensing of drugs, such as the 1962 Kefauver Harris Amendment (US), 1965 Directive 65/65/EEC1 (EU), and the Medicines Act 1968 (UK). In the United States, the new regulations strengthened the FDA, among other ways, by requiring applicants to prove efficacy and to disclose all side effects encountered in testing. The FDA subsequently initiated the Drug Efficacy Study Implementation to reclassify drugs already on the market. | 0 | Theoretical and Fundamental Chemistry |
A Fermi transition is a beta decay in which the spins of the emitted electron (positron) and anti-neutrino (neutrino) couple to total spin , leading to an angular momentum change between the initial and final states of the nucleus (assuming an allowed transition). In the non-relativistic limit, the nuclear part of the operator for a Fermi transition is given by
with the weak vector coupling constant, the isospin raising and lowering operators, and running over all protons and neutrons in the nucleus. | 0 | Theoretical and Fundamental Chemistry |
Even though amorphous materials exhibit no long-range periodic atomic ordering, there is still significant and varied local structure at inter-atomic length scales (see structure of liquids and glasses). Different local structures can produce amorphous phases of the same chemical composition with different physical properties such as density. In several cases sharp transitions have been observed between two different density amorphous states of the same material. Amorphous ice is one important example (see also examples below). Several of these transitions (including water) are expected to end in a second critical point. | 0 | Theoretical and Fundamental Chemistry |
The solution containing the relevant substance to be analysed is drawn into the burner and dispersed into the flame as a fine spray. The solvent evaporates first, leaving finely divided solid particles which move to the hottest region of the flame where gaseous atoms and ions are produced through the dissociation of molecules. Here electrons are excited as described above, and the spontaneously emit photon to decay to lower energy states. It is common for a monochromator to be used to allow for easy detection.
On a simple level, flame emission spectroscopy can be observed using just a flame and samples of metal salts. This method of qualitative analysis is called a flame test. For example, sodium salts placed in the flame will glow yellow from sodium ions, while strontium (used in road flares) ions color it red. Copper wire will create a blue colored flame, however in the presence of chloride gives green (molecular contribution by CuCl). | 0 | Theoretical and Fundamental Chemistry |
After the initial stage of embryogenesis, the implantation of the embryo and the initiation of placenta formation are associated with EMT. The trophoectoderm cells undergo EMT to facilitate the invasion of endometrium and appropriate placenta placement, thus enabling nutrient and gas exchange to the embryo. Later in embryogenesis, during gastrulation, EMT allows the cells to ingress in a specific area of the embryo – the primitive streak in amniotes, and the ventral furrow in Drosophila. The cells in this tissue express E-cadherin and apical-basal polarity. Since gastrulation is a very rapid process, E-cadherin is repressed transcriptionally by Twist and SNAI1 (commonly called Snail), and at the protein level by P38 interacting protein. The primitive streak, through invagination, further generates mesoendoderm, which separates to form a mesoderm and an endoderm, again through EMT. Mesenchymal cells from the primitive streak participate also in the formation of many epithelial mesodermal organs, such as notochord as well as somites, through the reverse of EMT, i.e. mesenchymal–epithelial transition. Amphioxus forms an epithelial neural tube and dorsal notochord but does not have the EMT potential of the primitive streak. In higher chordates, the mesenchyme originates out of the primitive streak migrates anteriorly to form the somites and participate with neural crest mesenchyme in formation of the heart mesoderm.
In vertebrates, epithelium and mesenchyme are the basic tissue phenotypes. During embryonic development, migratory neural crest cells are generated by EMT involving the epithelial cells of the neuroectoderm. As a result, these cells dissociate from neural folds, gain motility, and disseminate to various parts of the embryo, where they differentiate to many other cell types. Also, craniofacial crest mesenchyme that forms the connective tissue forming the head and face, is formed by neural tube epithelium by EMT. EMT takes place during the construction of the vertebral column out of the extracellular matrix, which is to be synthesized by fibroblasts and osteoblasts that encircle the neural tube. The major source of these cells are sclerotome and somite mesenchyme as well as primitive streak. Mesenchymal morphology allows the cells to travel to specific targets in the embryo, where they differentiate and/or induce differentiation of other cells.
During wound healing, keratinocytes at the border of the wound undergo EMT and undergo re-epithelialization or MET when the wound is closed. Snail2 expression at the migratory front influences this state, as its overexpression accelerates wound healing. Similarly, in each menstrual cycle, the ovarian surface epithelium undergoes EMT during post-ovulatory wound healing. | 1 | Applied and Interdisciplinary Chemistry |
When a liquid drop strikes a dry solid surface, it generally spreads on the surface, and then will retract if the impact is energetic enough to cause the drop to spread out more than it would generally spread due to its static receding contact angle. The specific outcome of the impact depends mostly upon the drop size, velocity, surface tension, viscosity, and also upon the surface roughness and the contact angle between the drop and the surface. Droplet impact parameters such as contact time and impact regime can be modified and controlled by different passive and active methods. | 1 | Applied and Interdisciplinary Chemistry |
Santiago Ramón y Cajal proposed that neurons are not continuous throughout the body, yet still communicate with each other, an idea known as the neuron doctrine. The word "synapse" was introduced in 1897 by the English neurophysiologist Charles Sherrington in Michael Fosters Textbook of Physiology. Sherrington struggled to find a good term that emphasized a union between two separate elements, and the actual term "synapse" was suggested by the English classical scholar Arthur Woollgar Verrall, a friend of Foster. The word was derived from the Greek synapsis (), meaning "conjunction", which in turn derives from synaptein (), from syn () "together" and haptein' () "to fasten".
However, while the synaptic gap remained a theoretical construct, and was sometimes reported as a discontinuity between contiguous axonal terminations and dendrites or cell bodies, histological methods using the best light microscopes of the day could not visually resolve their separation which is now known to be about 20 nm. It needed the electron microscope in the 1950s to show the finer structure of the synapse with its separate, parallel pre- and postsynaptic membranes and processes, and the cleft between the two. | 1 | Applied and Interdisciplinary Chemistry |
in chemistry, sulfoxidation refers to two distinct reactions.
In one meaning, sulfoxidation refers to the reaction of alkanes with a mixture of sulfur dioxide and oxygen. This reaction is employed industrially to produce alkyl sulfonic acids, which are used as surfactants. The reaction requires UV-radiation.
The reaction favors secondary positions in accord with its free-radical mechanism. Mixtures are produced. Semiconductor-sensitized variants have been reported.
Sulfoxidation can also refer to the oxidation of a thioether to a sulfoxide.
A typical source of "O" is hydrogen peroxide. | 0 | Theoretical and Fundamental Chemistry |
Free radicals derived from mercaptans, called thiyl radicals, are commonly invoked to explain reactions in organic chemistry and biochemistry. They have the formula RS where R is an organic substituent such as alkyl or aryl. They arise from or can be generated by a number of routes, but the principal method is H-atom abstraction from thiols. Another method involves homolysis of organic disulfides. In biology thiyl radicals are responsible for the formation of the deoxyribonucleic acids, building blocks for DNA. This conversion is catalysed by ribonucleotide reductase (see figure). Thiyl intermediates also are produced by the oxidation of glutathione, an antioxidant in biology. Thiyl radicals (sulfur-centred) can transform to carbon-centred radicals via hydrogen atom exchange equilibria. The formation of carbon-centred radicals could lead to protein damage via the formation of C−C bonds or backbone fragmentation.
Because of the weakness of the S−H bond, thiols can function as scavengers of free radicals. | 0 | Theoretical and Fundamental Chemistry |
Before the invention of Limans, their creators as well as scientists expected several positive and/or negative impacts:
* They expected a negative soil salinisation due to salt deposition and/or high evaporation rates. This was not the case.
* Carbon sequestration: Because of the biomass increase, a CO uptake is expected.
* Scientists were hoping for a methane uptake, but it could not be measured in limans. Instead, they found a shallow zone of methane production.
* Because desert crusts prevent rainwater from infiltrating the ground, they generate surface run-off that can lead to flash floods and to top-soil erosion. Limans prevent both the loss of surface runoff and of topsoil, as well as plant nutrients. On top of that, they provide a controlled place to deposit these resources.
* So far, no ecological research has been conducted on biodiversity within limans. | 1 | Applied and Interdisciplinary Chemistry |
By experiments described in his 1954 paper, Bagnold showed that when a shear flow is applied to the suspension, then the shear and normal stresses in the suspension may vary linearly or quadratically with the shear rate, depending on the strength of viscous effects compared to the particles' inertia.
If the shear and normal stresses in the mixture (suspension: mixture of solid and fluid) vary quadratically with the shear rate, the flow is said to satisfy Bagnold’s grain-inertia flow. If this relation is linear, then the motion is said to satisfy Bagnold’s macro-viscous flow.
These relationships, particularly the quadratic relationship, are referred to as the Bagnold rheology.
Although Bagnold used wax spheres suspended in a glycerin-water-alcohol mixture, many subsequent shear-cell experiments for both wet and dry mixtures, as well as computer simulations, have confirmed these relations.
Bagnold's rheology can be used to describe debris and granular flows down inclined slopes. | 1 | Applied and Interdisciplinary Chemistry |
Although the biosynthetic pathway of callystatin A has not been explicitly described, its polyketide structure indicates that the pathway must involve the polyketide synthase (PKS) enzyme complex. In general, in a modular fashion, an acetate starting unit in the loading module is extended by two carbons each time by the ketosynthase (KS) domain. The acyl groups are loaded onto the acyl carrier protein (ACP) with the help of the acyltransferase (AT) domain. Each module contains different combinations of the ketoreductase (KR), dehydratase (DH), and enoyl reductase (ER) domains that can modify and tailor the two-carbon subunits to form the resulting fatty acid chain. The final module contains a thioesterase (TE) domain that hydrolyzes the thioester bond to release the fatty acid chain and coenzyme A.
In the same manner, callystatin A biosynthesis starts with an acetate unit and elongates by either the malonate or the methyl malonate extender units, depending on the specific module. An exception to this is in module 7 where an ethyl malonate molecule replaces the other two options as the extender unit. It is assumed that the stereochemistry results from the activity of the domains and the absolute configuration is specified by the overall PKS complex. After being released from the thioesterase domain as a long fatty acid chain, the characteristic α,β-unsaturated lactone moiety is formed through a lactonization step to result in the final structure. | 0 | Theoretical and Fundamental Chemistry |
Gamma rays cause damage at a cellular level and are penetrating, causing diffuse damage throughout the body. However, they are less ionising than alpha or beta particles, which are less penetrating.
Low levels of gamma rays cause a stochastic health risk, which for radiation dose assessment is defined as the probability of cancer induction and genetic damage. The International Commission on Radiological Protection says "In the low dose range, below about 100 mSv, it is scientifically plausible to assume that the incidence of cancer or heritable effects will rise in direct proportion to an increase in the equivalent dose in the relevant organs and tissues" High doses produce deterministic effects, which is the severity of acute tissue damage that is certain to happen. These effects are compared to the physical quantity absorbed dose measured by the unit gray (Gy). | 0 | Theoretical and Fundamental Chemistry |
By introducing an asymmetric field effect along the nanochannel, a field-effect reconfigurable nanofluidic diode is feasible, which features post-fabrication reconfiguration of the diode functions, such as the forward/reverse directions and the rectification degrees. Unlike the nanofluidic field-effect transistor, where only the amount of ions/molecules is regulated by an electrostatic potential, the field-effect reconfigurable diode can be used to control both directions and magnitudes of ion/molecule transport. This device could be deemed as the building blocks for ionic counterpart of the electronic field-programmable gate array. | 0 | Theoretical and Fundamental Chemistry |
Chemical libraries are usually generated for a specific goal and larger chemical libraries could be made of several groups of smaller libraries stored in the same location. In the drug discovery process for instance, a wide range of organic chemicals are needed to test against models of disease in high-throughput screening. Therefore, most of the chemical synthesis needed to generate chemical libraries in drug discovery is based on organic chemistry. A company that is interested in screening for kinase inhibitors in cancer may limit their chemical libraries and synthesis to just those types of chemicals known to have affinity for ATP binding sites or allosteric sites.
Generally, however, most chemical libraries focus on large groups of varied organic chemical series where an organic chemist can make many variations on the same molecular scaffold or molecular backbone. Sometimes chemicals can be purchased from outside vendors as well and included into an internal chemical library.
Depending upon their scope and design, chemical libraries can also be classified as diverse oriented, Drug-like, Lead-like, peptide-mimetic, Natural Product-like, Targeted against a specific family of biological targets such Kinases, GPCRs, Proteases, PPI etc. These chemical libraries are often used in target based drug discovery (reverse pharmacology). Among the compound libraries should be annotated the Fragment Compound Libraries, which are mainly used for Fragment-based lead discovery. | 1 | Applied and Interdisciplinary Chemistry |
Magnesium transporters are proteins that transport magnesium across the cell membrane. All forms of life require magnesium, yet the molecular mechanisms of Mg uptake from the environment and the distribution of this vital element within the organism are only slowly being elucidated.
The ATPase function of MgtA is highly cardiolipin dependent and has been shown to detect free magnesium in the μM range
In bacteria, Mg is probably mainly supplied by the CorA protein and, where the CorA protein is absent, by the MgtE protein. In yeast the initial uptake is via the Alr1p and Alr2p proteins, but at this stage the only internal Mg distributing protein identified is Mrs2p. Within the protozoa only one Mg transporter (XntAp) has been identified. In metazoa, Mrs2p and MgtE homologues have been identified, along with two novel Mg transport systems TRPM6/TRPM7 and PCLN-1. Finally, in plants, a family of Mrs2p homologues has been identified along with another novel protein, AtMHX. | 1 | Applied and Interdisciplinary Chemistry |
Copepods vary considerably, but are typically long, with a teardrop-shaped body and large antennae. Like other crustaceans, they have an armoured exoskeleton, but they are so small that in most species, this thin armour and the entire body is almost totally transparent. Some polar copepods reach . Most copepods have a single median compound eye, usually bright red and in the centre of the transparent head. Subterranean species may be eyeless, and members of the genera Copilia and Corycaeus possess two eyes, each of which has a large anterior cuticular lens paired with a posterior internal lens to form a telescope. Like other crustaceans, copepods possess two pairs of antennae; the first pair is often long and conspicuous.
Free-living copepods of the orders Calanoida, Cyclopoida, and Harpacticoida typically have a short, cylindrical body, with a rounded or beaked head, although considerable variation exists in this pattern. The head is fused with the first one or two thoracic segments, while the remainder of the thorax has three to five segments, each with limbs. The first pair of thoracic appendages is modified to form maxillipeds, which assist in feeding. The abdomen is typically narrower than the thorax, and contains five segments without any appendages, except for some tail-like "rami" at the tip. Parasitic copepods (the other seven orders) vary widely in morphology and no generalizations are possible.
Because of their small size, copepods have no need of any heart or circulatory system (the members of the order Calanoida have a heart, but no blood vessels), and most also lack gills. Instead, they absorb oxygen directly into their bodies. Their excretory system consists of maxillary glands. | 1 | Applied and Interdisciplinary Chemistry |
The mechanism consists of three well-differentiated reactions:
# Phenol O-acylation with formation of a tetrahedral intermediate
# Intramolecular aldol condensation to cyclize and to form a hydroxydihydrochromone
# Elimination of the hydroxyl group to form the chromone (or coumarin) | 0 | Theoretical and Fundamental Chemistry |
Albert Strickler was the only child of Albert Strickler, Sr. (1853–1936) and Maria Auguste Flentjen (1863–1945) of Wädenswil, Canton of Zürich, Switzerland. He was married twice, the second time as a widower. Neither marriage produced children.
Strickler graduated from ETH Zurich as a mechical engineer in 1911. He earned a Ph.D. in 1917 while serving as the principal assistant to Professor Franz Prasil (1857–1929). Throughout his career, he was involved in the development of hydropower with interests ranging from hydraulic machinery to the regulation of river flows for inland navigation. Prior to World War II, he was the vice president of the Association of Exporting Electricity and a member of the board of directors on the Gotthard Electricity Mains AG, Altdorf, Uri. He subsequently worked as an engineering consultant until illness forced his withdrawal from practice in 1950. | 1 | Applied and Interdisciplinary Chemistry |
To demonstrate its capability in rapidly depolymerizing in presence of UV-light, DiLauro et al. synthesized a PPA polymer with two UV-sensitive endcaps, 2-nitro-4,5-dimethoxybenzyl alcohol and 1-[[(chlorocarbonyl)oxy]methyl]-4,5-dimethoxy-2 nitrobenzene, and were able to achieve complete depolymerization in a few minutes. In a practical application in organic electronics, cyclic PPA in the presence of 2-(4-methoxystyryl)-4,6-bis(trichloromethyl)-1,3,5-triazine (MBTT used as PAG) undergoes depolymerization upon exposure to UV-light, which in turn deactivates the transient electronics. Another similar application in transient electronics was reported where an organic light-emitting diode (OLED) was integrated on the PPA substrate and can cause depolymerization in the presence of a PAG. | 0 | Theoretical and Fundamental Chemistry |
As early as 1895 in the UK it was being noted that the heyday of the Bessemer process was over and that the open hearth method predominated. The Iron and Coal Trades Review said that it was "in a semi-moribund condition. Year after year, it has not only ceased to make progress, but it has absolutely declined." It has been suggested, both at that time and more recently, that the cause of this was the lack of trained personnel and investment in technology rather than anything intrinsic to the process itself. For example, one of the major causes of the decline of the giant ironmaking company Bolckow Vaughan of Middlesbrough was its failure to upgrade its technology. The basic process, the Thomas-Gilchrist process, remained in use longer, especially in Continental Europe, where iron ores were of high phosphorus content and the open-hearth process was not able to remove all phosphorus; almost all inexpensive construction steel in Germany was produced with this method in the 1950s and 1960s. It was eventually superseded by basic oxygen steelmaking.
In the U.S., commercial steel production using this method stopped in 1968. It was replaced by processes such as the basic oxygen (Linz–Donawitz) process, which offered better control of final chemistry. The Bessemer process was so fast (10–20 minutes for a heat) that it allowed little time for chemical analysis or adjustment of the alloying elements in the steel. Bessemer converters did not remove phosphorus efficiently from the molten steel; as low-phosphorus ores became more expensive, conversion costs increased. The process permitted only limited amount of scrap steel to be charged, further increasing costs, especially when scrap was inexpensive. Use of electric arc furnace technology competed favourably with the Bessemer process resulting in its obsolescence.
Basic oxygen steelmaking is essentially an improved version of the Bessemer process (decarburization by blowing oxygen as gas into the heat rather than burning the excess carbon away by adding oxygen carrying substances into the heat). The advantages of pure oxygen blast over air blast were known to Henry Bessemer, but 19th-century technology was not advanced enough to allow for the production of the large quantities of pure oxygen necessary to make it economical. | 1 | Applied and Interdisciplinary Chemistry |
Indirect photocatalysis may occur via the production of a reactive species which then participates in another reaction. For example, photodegradation of certain compounds has been observed in the presence of kaolinite and montmorillonite, and this may proceed via the formation of reactive oxygen species at the surface of these clay minerals. Indeed, reactive oxygen species have been observed when soil surfaces are exposed to sunlight. The ability of irradiated soil to generate singlet oxygen was found to be independent of the organic matter content, and both the mineral and organic components of soil appear to contribute to this process. Indirect photolysis in soil has been observed to occur at depths of up to 2 mm due to migration of reactive species; in contrast, direct photolysis (in which the degraded compound itself absorbs light) was restricted to a "photic depth" of 0.2 to 0.4 mm. Like certain minerals, organic matter in solution, as well as particulate organic matter, may act as an indirect catalyst via formation of singlet oxygen which then reacts with other compounds. | 0 | Theoretical and Fundamental Chemistry |
On 25 April 1945, an armoured task force from the British/American Alsos Mission arrived in Tailfingen, and surrounded the Kaiser Wilhelm Institute for Chemistry. Hahn was informed that he was under arrest. When asked about reports related to his secret work on uranium, Hahn replied: "I have them all here", and handed over 150 reports. He was taken to Hechingen, where he joined Erich Bagge, Horst Korsching, Max von Laue, Carl Friedrich von Weizsäcker and Karl Wirtz. They were then taken to a dilapidated château in Versailles, where they heard about the signing of the German Instrument of Surrender at Reims on 7 May. Over the following days they were joined by Kurt Diebner, Walther Gerlach, Paul Harteck and Werner Heisenberg. All were physicists except Hahn and Harteck, who were chemists, and all had worked on the German nuclear weapons program except von Laue, although he was well aware of it.
They were relocated to the Château de Facqueval in Modave, Belgium, where Hahn used the time to work on his memoirs and then, on 3 July, were flown to England. They arrived at Farm Hall, Godmanchester, near Cambridge, on 3 July. Unbeknown to them, their every conversation, indoors and out, was recorded from hidden microphones. They were given British newspapers, which Hahn was able to read. He was greatly disturbed by their reports of the Potsdam Conference, where German territory was ceded to Poland and the USSR. In August 1945, the German scientists were informed of the atomic bombing of Hiroshima. Up to this point the scientists, except Harteck, were completely certain that their project was further advanced than any in other countries, and the Alsos Mission's chief scientist, Samuel Goudsmit, did nothing to correct this impression. Now the reason for their incarceration in Farm Hall suddenly became apparent.
As they recovered from the shock of the announcement, they began to rationalise what had happened. Hahn noted that he was glad that they had not succeeded, and von Weizsäcker suggested that they should claim that they had not wanted to. They drafted a memorandum on the project, noting that fission was discovered by Hahn and Strassmann. The revelation that Nagasaki had been destroyed by a plutonium bomb came as another shock, as it meant that the Allies had not only been able to successfully conduct uranium enrichment, but had mastered nuclear reactor technology as well. The memorandum became the first draft of a postwar apologia. The idea that Germany had lost the war because its scientists were morally superior was as outrageous as it was unbelievable, but struck a chord in postwar German academia. It infuriated Goudsmit, whose parents had been murdered in Auschwitz. On 3 January 1946, exactly six months after they had arrived at Farm Hall, the group was allowed to return to Germany. Hahn, Heisenberg, von Laue and von Weizsäcker were brought to Göttingen, which was controlled by the British occupation authorities. | 0 | Theoretical and Fundamental Chemistry |
Due to fluid processing, photoelectric effect and thermoelectric measurement and subtraction between the sample and the detector, the optoelectronic technology used in the standard distribution systematically underestimates the thermal diffusivity of the solid sample. In order to solve the negative effects in the process of treating fluids in this study, a completely new method will be proposed. It depends on the application of the transparent thermoelectric sensor as well as the transparent coupling of the fluid, as well as the self-standardization process. In this sense, it is easy to measure examples of accurate opacity and solidity of thermal diffusivity, as well as the light absorption coefficient of translucent solid samples. | 0 | Theoretical and Fundamental Chemistry |
EBSD detectors can have forward scattered electron diodes (FSD) at the bottom, in the middle (MSD) and at the top of the detector. Forward-scattered electron (FSE) imaging involves collecting electrons scattered at small angles from the surface of a sample, which provides information about the surface topography and composition. The FSE signal is also sensitive to the crystallographic orientation of the sample. By analysing the intensity and contrast of the FSE signal, researchers can determine the crystallographic orientation of each pixel in the image.
The FSE signal is typically collected simultaneously with the BSE signal in EBSD analysis. The BSE signal is sensitive to the average atomic number of the sample, and is used to generate an image of the surface topography and composition. The FSE signal is superimposed on the BSE image to provide information about the crystallographic orientation.
Image generation has a lot of freedom when using the EBSD detector as an imaging device. An image created using a combination of diodes is called virtual or VFSD. It is possible to acquire images at a rate akin to slow scan imaging in the SEM by excessive binning of the EBSD CCD camera. It is possible to suppress or isolate the contrast of interest by creating composite images from simultaneously captured images, which offers a wide range of combinations for assessing various microstructure characteristics. Nevertheless, VFSD images do not include the quantitative information inherent to traditional EBSD maps; they simply offer representations of the microstructure. | 0 | Theoretical and Fundamental Chemistry |
The geometry and bonding of a Zintl ion cannot be easily described by classical two electron two center bonding theories; however the geometries Zintl ions can be well described by Wade’s rules of boranes. Wade’s rules offer an alternative model for the relationship between geometry and electron count in delocalized electron deficient systems. The rules were developed to predict the geometries of boranes from the number of electrons and can be applied to these polyanions by replacing the BH unit with a lone pair. Some unique clusters of Ge occur in non-deltahedral shapes that cannot be described by Wade’s rules. The rules also become more convoluted in intermetallic clusters with transition metals and consideration needs to be taken for the location of the additional electrons. | 0 | Theoretical and Fundamental Chemistry |
The touchdown polymerase chain reaction or touchdown style polymerase chain reaction is a method of polymerase chain reaction by which primers avoid amplifying nonspecific sequences. The annealing temperature during a polymerase chain reaction determines the specificity of primer annealing. The melting point of the primer sets the upper limit on annealing temperature. At temperatures just above this point, only very specific base pairing between the primer and the template will occur. At lower temperatures, the primers bind less specifically. Nonspecific primer binding obscures polymerase chain reaction results, as the nonspecific sequences to which primers anneal in early steps of amplification will "swamp out" any specific sequences because of the exponential nature of polymerase amplification. | 1 | Applied and Interdisciplinary Chemistry |
In organic chemistry, enone–alkene cycloadditions are a version of the [[woodward-Hoffman rules|[2+2] cycloaddition]] This reaction involves an enone and alkene as substrates. Although the concerted photochemical [2+2] cycloaddition is allowed, the reaction between enones and alkenes is stepwise and involves discrete diradical intermediates. | 0 | Theoretical and Fundamental Chemistry |
In fluid dynamics, the entrance length is the distance a flow travels after entering a pipe before the flow becomes fully developed. Entrance length refers to the length of the entry region, the area following the pipe entrance where effects originating from the interior wall of the pipe propagate into the flow as an expanding boundary layer. When the boundary layer expands to fill the entire pipe, the developing flow becomes a fully developed flow, where flow characteristics no longer change with increased distance along the pipe. Many different entrance lengths exist to describe a variety of flow conditions. Hydrodynamic entrance length describes the formation of a velocity profile caused by viscous forces propagating from the pipe wall. Thermal entrance length describes the formation of a temperature profile. Awareness of entrance length may be necessary for the effective placement of instrumentation, such as fluid flow meters. | 1 | Applied and Interdisciplinary Chemistry |
The three main side reactions that produce impurities have in common that they decompose urea.
Urea hydrolyzes back to ammonium carbamate in the hottest stages of the synthesis plant, especially in the stripper, so residence times in these stages are designed to be short.
Biuret is formed when two molecules of urea combine with the loss of a molecule of ammonia.
Normally this reaction is suppressed in the synthesis reactor by maintaining an excess of ammonia, but after the stripper, it occurs until the temperature is reduced. Biuret is undesirable in urea fertilizer because it is toxic to crop plants to varying degrees, but it is sometimes desirable as a nitrogen source when used in animal feed.
Isocyanic acid HNCO and ammonia results from the thermal decomposition of ammonium cyanate , which is in chemical equilibrium with urea:
This decomposition is at its worst when the urea solution is heated at low pressure, which happens when the solution is concentrated for prilling or granulation (see below). The reaction products mostly volatilize into the overhead vapours, and recombine when these condense to form urea again, which contaminates the process condensate. | 0 | Theoretical and Fundamental Chemistry |
If the proton and neutron are part of an atomic nucleus, the above described decay processes transmute one chemical element into another. For example:
Beta decay does not change the number () of nucleons in the nucleus, but changes only its charge . Thus the set of all nuclides with the same can be introduced; these isobaric nuclides may turn into each other via beta decay. For a given there is one that is most stable. It is said to be beta stable, because it presents a local minimum of the mass excess: if such a nucleus has numbers, the neighbour nuclei and have higher mass excess and can beta decay into , but not vice versa. For all odd mass numbers , there is only one known beta-stable isobar. For even , there are up to three different beta-stable isobars experimentally known; for example, , , and are all beta-stable. There are about 350 known beta-decay stable nuclides. | 0 | Theoretical and Fundamental Chemistry |
Thioamides are typically prepared by treating amides with phosphorus sulfides such as phosphorus pentasulfide, a reaction first described in the 1870s. Alternative routes include the use of Lawesson's reagent or the reaction of nitriles with hydrogen sulfide:
The Willgerodt-Kindler reaction also gives benzylthioamides.
The C(R)(N)(S) core of thioamides is planar. Using thioacetamide as representative: the C-S, C-N, and C-C distances are 1.68, 1.31, and 1.50 Å, respectively. The short C-S and C-N distances indicate multiple bonding. | 0 | Theoretical and Fundamental Chemistry |
Immunotherapy is a treatment used to produce immunity to a disease or enhance the resistance of the immune system to an active disease process, such as cancer
Wnt and Fz genes are frequently overexpressed in head and neck squamous cell carcinoma (HNSCC). Treatment of a HNSCC cell line (SNU 1076) with anti-Wnt1 antibodies reduced the activity of the Wnt/Fz dependent transcription factor LEF/TCF and diminished the expression of cyclin D1 and B-catenin proteins. Similar to anti-Wnt antibodies, treatment with recombinant SFRP1 inhibited growth of SNU 1076 cells as well. This suggests that Wnt and Fz receptors may be attractive targets for immunotherapy and drug therapy of HNSCC. | 1 | Applied and Interdisciplinary Chemistry |
In colonial times, simple cooking techniques were used to create one pot meals like ham and potato casserole, clam chowder, or stews with common ingredients like oysters, chicken or venison. When John Smith landed in Chesapeake in 1608, he wrote: "The fish were so thick, we attempted to catch them with frying pans". Common regional ingredients in the local cuisine of Chesapeake included terrapins, smoked hams, blue crab, shellfish, local fish, game meats and various species of waterfowl. Blue crab continues to be an especially popular regional specialty. | 1 | Applied and Interdisciplinary Chemistry |
As the name would suggest this type of response is triggered by very low levels of light and is thought to be mediated by phytochrome A. It can be initiated by fluences as low as 0.0001μmol/m up to about 0.05μmol/m. Germination of Arabidopsis can be induced with very low levels of red light, as can oat seedlings. Such low levels of light are sufficient for inducing this response since they only convert 0.02% of the phytochrome to its active form. The backward reaction by far red light is only 98% efficient making the conversion non-photoreversible and allowing the response to proceed. VLFRs can also be induced by making up the required fluence by brief flashes of light. Since this depends on light levels and time it is known as the law of reciprocity. | 0 | Theoretical and Fundamental Chemistry |
Dexlansoprazole was approved by the U.S. Food and Drug Administration (FDA) in 2009, and was approved in Canada in 2010 and in Mexico in 2011.
Since Kapidex was approved in 2009, there have been reports of dispensing errors because of confusion with the drugs Casodex (bicalutamide) and Kadian (morphine), which have very different uses from Kapidex and from each other. In 2010, the FDA approved a name change for Kapidex to avoid confusion with the two other medications and Takeda began marketing it under the new name Dexilant. It is also available in Bangladesh for the first time as Dexlan by IBN SINA Pharmaceuticals Ltd. in April 2014 and after them DEXILEND by Ziska Pharmaceuticals Ltd., Desopra by Alco Pharma, Delanix by Incepta Pharmaceuticals, Dexogut by Popular Pharmaceuticals Ltd. also introduced it in BD market. In 2020 many other Pharmaceuticals have launched Dexlansoprazole. | 0 | Theoretical and Fundamental Chemistry |
* Chemical Bonding and Molecular Geometry: From Lewis to Electron Densities (Topics in Inorganic Chemistry) by Ronald J. Gillespie and Paul L. A. Popelier
* Atoms, Molecules and Reactions: An Introduction to Chemistry by Ronald J. Gillespie
* Chemistry by Ronald J. Gillespie, David Humphreys, Colin Baird, and E. A. Robinson
* Atoms, Molecules and Reactions: An Introduction to Chemistry with D.A. Humphreys, E.A. Robinson and D.R. Eaton, Prentice Hall, 1994 | 0 | Theoretical and Fundamental Chemistry |
The method uses seasonal water balance components as input data. These are related to the surface hydrology (like rainfall, evaporation, irrigation, use of drain and well water for irrigation, runoff), and the aquifer hydrology (like upward seepage, natural drainage, pumping from wells). The other water balance components (like downward percolation, upward capillary rise, subsurface drainage) are given as output.<br>
The quantity of drainage water, as an output, is determined by two drainage intensity factors for drainage above and below drain level respectively (to be given with the input data), a drainage reduction factor (to simulate a limited operation of the drainage system), and the height of the water table, resulting from the computed water balance. Variation of the drainage intensity factors and the drainage reduction factor gives the opportunity to simulate the effect of different drainage options. | 0 | Theoretical and Fundamental Chemistry |
The method was created in the Molecular Genetics laboratory of the Russian Cardiology Research Institute and was published in 2003 by Kryndushkin et al. The original method used a TAE buffering system and incorporated a modified vacuum blotting system for the transfer of proteins onto a membrane (originally PVDF). The modified vacuum blotting system is actually a vacuum-assisted capillary transfer, since the vacuum only helps fluid that has already gone through the gel and membrane to leave the system. | 1 | Applied and Interdisciplinary Chemistry |
Some varying factors in splat quenching are the drop size and velocity of the metal in ensuring the complete solidification of the metal. In cases where the volume of the drop is too large or the velocity is too slow, the metal will not solidify past equilibrium causing it to remelt. Therefore, experiments are carried out to determine the precise volume and velocity of the droplet that will ensure complete solidification of a certain metal.
Intrinsic and extrinsic factors influencing the glass-forming ability of metallic alloys were analyzed and classified. | 1 | Applied and Interdisciplinary Chemistry |
For an incident unpolarized photon of energy , the differential cross section is:
where
* is the classical electron radius (~2.82 fm, is about 7.94 × 10 m or 79.4 mb)
* is the ratio of the wavelengths of the incident and scattered photons
* is the scattering angle (0 for an undeflected photon).
The angular dependent photon wavelength (or energy, or frequency) ratio is
as required by the conservation of relativistic energy and momentum (see Compton scattering). The dimensionless quantity expresses the energy of the incident photon in terms of the electron rest energy (~511 keV), and may also be expressed as increases monotonically with the deflection angle, from (forward scattering, no energy transfer) to (180 degree backscatter, maximum energy transfer).
In some cases it is convenient to express the classical electron radius in terms of the Compton wavelength: , where is the fine structure constant (~1/137) and is the reduced Compton wavelength of the electron (~0.386 pm), so that the constant in the cross section may be given as: | 0 | Theoretical and Fundamental Chemistry |
Subsets and Splits
No community queries yet
The top public SQL queries from the community will appear here once available.