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Scytovirin is a 95-amino acid antiviral protein isolated from the cyanobacteria Scytonema varium. It has been cultured in E. coli and its structure investigated in detail. Scytovirin is thought to be produced by the bacteria to protect itself from viruses that might otherwise attack it, but as it has broad-spectrum ant...
1
Biochemistry
Photoreceptor cells are unusual cells in that they depolarize in response to absence of stimuli or scotopic conditions (darkness). In photopic conditions (light), photoreceptors hyperpolarize to a potential of −60 mV. In the dark, cGMP levels are high and keep cGMP-gated sodium channels open allowing a steady inward cu...
1
Biochemistry
In order to get a meaningful sulfur signal from the analysis, the buffer should not contain sulfur (i.e. no BES, DDT, HEPES, MES, MOPSO or PIPES compounds). Excessive amounts of chlorine in the buffer should also be avoided, since this will overlap with the sulfur peak; KBr and NaBr are suitable alternatives.
7
Physical Chemistry
Hydrocarbons, primarily paraffins (CH) and lipids but also sugar alcohols. * Advantages ** Freeze without much supercooling ** Ability to melt congruently ** Self nucleating properties ** Compatibility with conventional material of construction ** No segregation ** Chemically stable ** Safe and non-reactive * Disadvant...
7
Physical Chemistry
Liquid is one of the four primary states of matter, with the others being solid, gas and plasma. A liquid is a fluid. Unlike a solid, the molecules in a liquid have a much greater freedom to move. The forces that bind the molecules together in a solid are only temporary in a liquid, allowing a liquid to flow while a so...
7
Physical Chemistry
Quantities, Units and Symbols in Physical Chemistry, also known as the Green Book, is a compilation of terms and symbols widely used in the field of physical chemistry. It also includes a table of physical constants, tables listing the properties of elementary particles, chemical elements, and nuclides, and information...
3
Analytical Chemistry
There is one Public Analyst Laboratory in each of Guernsey, Isle of Man and Jersey serving the needs of these islands.
2
Environmental Chemistry
The Caspian Sea is at its South Caspian Basin, like the Black Sea, a remnant of the ancient Paratethys Sea. Its seafloor is, therefore, a standard oceanic basalt and not a continental granite body. It is estimated to be about 30 million years old, and became landlocked in the Late Miocene, about 5.5 million years ago, ...
2
Environmental Chemistry
Accurate detection and quantification are the most vital components of the TOC analysis process. Conductivity and non-dispersive infrared (NDIR) are the two common detection methods used in modern TOC analyzers.
3
Analytical Chemistry
Atomic absorption spectroscopy (AAS) and atomic emission spectroscopy (AES) is a spectroanalytical procedure for the quantitative determination of chemical elements by free atoms in the gaseous state. Atomic absorption spectroscopy is based on absorption of light by free metallic ions. In analytical chemistry the tech...
3
Analytical Chemistry
Organic ionic plastic crystals – are a type organic salts exhibiting mesophases (i.e. a state of matter intermediate between liquid and solid), in which mobile ions are orientationally or rotationally disordered while their centers are located at the ordered sites in the crystal structure. They have various forms of di...
7
Physical Chemistry
The endothelial protease vasohibin uses a cysteine as the nucleophile, but a serine to coordinate the histidine base. Despite the serine being a poor acid, it is still effective in orienting the histidine in the catalytic triad. Some homologues alternatively have a threonine instead of serine at the acid location.
1
Biochemistry
A thermodynamic system consisting of a single phase, in the absence of external forces, in its own state of internal thermodynamic equilibrium, is homogeneous. This means that the material in any region of the system can be interchanged with the material of any congruent and parallel region of the system, and the effec...
7
Physical Chemistry
Sucrose esters were first mentioned in 1880 by Herzfeld who described the preparation of sucrose octaacetate. The substance is still in use today as a food additive. In 1921, Hess and Messner synthesized sucrose octapalmitate and sucrose octastearate. Both are sucrose fatty acid esters. Rosenthal, in 1924, synthesized ...
0
Organic Chemistry
The reaction mechanism of allylic C-H acetoxylation has been studied. The first step in the catalytic cycle is cleavage of the allylic C-H bond. The sulfoxide ligand is thought to promote this step by generating a highly electrophilic, possibly cationic palladium species in situ. This species coordinates to the alk...
0
Organic Chemistry
The word pesticide derives from the Latin pestis (plague) and caedere (kill). The Food and Agriculture Organization (FAO) has defined pesticide as: : any substance or mixture of substances intended for preventing, destroying, or controlling any pest, including vectors of human or animal disease, unwanted species of pla...
2
Environmental Chemistry
In discussing these figures, it should be kept in mind that both the radon distribution in dwelling and its effect at low exposures are not precisely known, and the radon health effect has to be computed (deaths caused by radon domestic exposure cannot be observed as such). These estimations are strongly dependent on t...
2
Environmental Chemistry
Steroid 21-hydroxylase is a cytochrome P450 enzyme that is notable for its substrate specificity and relatively high catalytic efficiency. Like other cytochrome P450 enzymes, steroid 21-hydroxylase participates in the cytochrome P450 catalytic cycle and engages in one-electron transfer with NADPH-P450 reductase. Steroi...
1
Biochemistry
In the field of energetics, an energy carrier is produced by human technology from a primary energy source. Only the energy sector uses primary energy sources. Other sectors of society use an energy carrier to perform useful activities (end-uses). The distinction between "Energy Carriers" (EC) and "Primary Energy Sourc...
7
Physical Chemistry
A primary alcohol is an alcohol in which the hydroxy group is bonded to a primary carbon atom. It can also be defined as a molecule containing a “–CHOH” group. In contrast, a secondary alcohol has a formula “–CHROH” and a tertiary alcohol has a formula “–CROH”, where “R” indicates a carbon-containing group. Examples of...
0
Organic Chemistry
In theoretical electrolysis of water, a voltage of only 1.23 V is required to split water into hydrogen and oxygen, The formation of an EDL increases this to its thermo-neutral voltage of 1.45 V. Minimising the EDL formed during pulse electrolysis is advantageous, as it can reduce the thermo-neutral voltage and the ene...
7
Physical Chemistry
The calcium cycle is a transfer of calcium between dissolved and solid phases. There is a continuous supply of calcium ions into waterways from rocks, organisms, and soils. Calcium ions are consumed and removed from aqueous environments as they react to form insoluble structures such as calcium carbonate and calcium si...
1
Biochemistry
When discussing the properties of acids it is usual to specify equilibrium constants as acid dissociation constants, denoted by K, with numerical values given the symbol pK. On the other hand, association constants are used for bases. However, general purpose computer programs that are used to derive equilibrium const...
7
Physical Chemistry
The siRNA-induced post transcriptional gene silencing is initiated by the assembly of the RNA-induced silencing complex (RISC). The complex silences certain gene expression by cleaving the mRNA molecules coding the target genes. To begin the process, one of the two siRNA strands, the guide strand (anti-sense strand), w...
1
Biochemistry
Hydrogels have the remarkable ability to swell in water and aqueous solvents. During the process of swelling, surface instability can occur. This instability depends on the thickness of the hydrogel layers and the surface tension. A higher surface tension stabilizes the flat surface of the hydrogel, which is the outer-...
7
Physical Chemistry
It has been suggested certain microbial dark matter genetic material could belong to a new (i.e., fourth) domain of life, although other explanations (e.g., viral origin) are also possible, which has ties with the issue of a hypothetical shadow biosphere.
1
Biochemistry
Catherine E. Costello is the William Fairfield Warren distinguished professor in the department of biochemistry, Cell Biology and Genomics, and the director of the Center for Biomedical Mass Spectrometry at the Boston University School of Medicine.
1
Biochemistry
In 1756 Thomas Melvill observed the emission of distinct patterns of colour when salts were added to alcohol flames. By 1785 James Gregory discovered the principles of diffraction grating and American astronomer David Rittenhouse made the first engineered diffraction grating. In 1821 Joseph von Fraunhofer solidified...
7
Physical Chemistry
Reports on the "classical" pharmacology of pempidine have been published. The Spinks group, at ICI, compared pempidine, its N-ethyl analogue, and mecamylamine in considerable detail, with additional data related to several structurally simpler compounds.
0
Organic Chemistry
An inexact differential or imperfect differential is a differential whose integral is path dependent. It is most often used in thermodynamics to express changes in path dependent quantities such as heat and work, but is defined more generally within mathematics as a type of differential form. In contrast, an integral o...
7
Physical Chemistry
The mother liquor (or spent liquor) is the solution remaining after a component has been removed by a some process such as filtration or more commonly crystallization. It is encountered in chemical processes including sugar refining. In crystallization, a solid (usually impure) is dissolved in a solvent at high tempera...
3
Analytical Chemistry
Amyotrophic lateral sclerosis (ALS), also called Lou Gehrig's disease, is a motor neuron disease that affects the brain and spinal cord. The disease causes motor neurons to degenerate, which eventually leads to neuron death and muscular degeneration. Hundreds of mutations in the Cu/Zn superoxide dismutase (SOD1) gene h...
1
Biochemistry
Third-generation Glycoazodyes are synthesized using amino sugars such as 6-amino-6-deoxy-D-galactose or 6 amino-6-deoxylactose. The point of the amide bond is controlled by protecting the alcohol groups on the sugar and allowing the free amine to react. The point of the ester group is controlled by choosing a azo dye w...
0
Organic Chemistry
Few commercial applications exist for bioplastics. Cost and performance remain problematic. Typical is the example of Italy, where biodegradable plastic bags are compulsory for shoppers since 2011 with the introduction of a specific law. Beyond structural materials, electroactive bioplastics are being developed that pr...
7
Physical Chemistry
In metallurgy, gas flushing removes dissolved gases from the molten metal prior to the material being processed. For example, before casting aluminium alloys, argon bubbles are injected into liquid aluminium using a rotary degasser. The argon bubbles rise to the surface, bringing with them some of the dissolved hydroge...
8
Metallurgy
For an isolated spherical solid particle of diameter in its own liquid, the Gibbs–Thomson equation for the structural melting point depression can be written: where: * T = bulk melting temperature * σ = solid–liquid interface energy (per unit area) * H = bulk enthalpy of fusion (per gram of material) * ρ = density of...
7
Physical Chemistry
The dithiodialkyphosphinic acids (RPSH) are related to the diorganodithiophosphates with the formula (RO)PSH, which are also used as complexing agents in the purification of metals. The phosphates are more prone to hydrolysis owing to the greater lability of the RO-P linkage vs the direct C-P bond.
0
Organic Chemistry
As illustrated in Retrosynthetic Scheme I, Taxol was derived from diol 7.2 by an ester bond formation, according to the Ojima-Holton method. This diol comes from carbonate 6.3 by the addition of phenyllithium. The oxetane ring in compound 6.3 was obtained via an S2 reaction involving a mesylate derived from acetal 4.9....
0
Organic Chemistry
In cancers, loss of expression of genes occurs about 10 times more frequently by transcription silencing (caused by promoter hypermethylation of CpG islands) than by mutations. As Vogelstein et al. point out, in a colorectal cancer there are usually about 3 to 6 driver mutations and 33 to 66 hitchhiker or passenger mu...
1
Biochemistry
McCrones work as a microscopist first attracted widespread public attention when he helped exonerate Lloyd Eldon Miller, a cabdriver who had been sentenced to death for the 1955 murder of an 8-year-old girl in Canton, Illinois. McCrone was able to show that the stains in a pair of undershorts that the prosecution had ...
3
Analytical Chemistry
Different rules (4n, 5n, or 6n) are invoked depending on the number of electrons per vertex. The 4n rules are reasonably accurate in predicting the structures of clusters having about 4 electrons per vertex, as is the case for many boranes and carboranes. For such clusters, the structures are based on deltahedra, whic...
7
Physical Chemistry
In polymerase chain reaction (PCR) experiments, the GC-content of short oligonucleotides known as primers is often used to predict their annealing temperature to the template DNA. A higher GC-content level indicates a relatively higher melting temperature. Many sequencing technologies, such as Illumina sequencing, have...
1
Biochemistry
* Nesmeyanov A.N. D.I. Mendeleev's Periodic Table of Elements and Organic Chemistry. Series: Reports at the plenary session/ VIII Mendeleev Congress on General and Applied Chemistry. Moscow: Publishing House Acad. Sciences of the USSR, 1959. * Nesmeyanov A.N. Ed. acad. A. V. Topchiev Selected Works. Moscow: Publishing ...
0
Organic Chemistry
Conventional SNP typing methods are typically time-consuming and expensive, requiring several probe based assays to be multiplexed together or the use of DNA microarrays. HRM is more cost-effective and reduces the need to design multiple pairs of primers and the need to purchase expensive probes. The HRM method has bee...
1
Biochemistry
The thylakoid lumen is a continuous aqueous phase enclosed by the thylakoid membrane. It plays an important role for photophosphorylation during photosynthesis. During the light-dependent reaction, protons are pumped across the thylakoid membrane into the lumen making it acidic down to pH 4.
5
Photochemistry
Wu was born 1 January 1928 in Jinan, Shandong, Republic of China. He graduated from the Department of Chemistry of Fudan University in 1951, and was hired as a faculty member by the university. In September 1954, he began his graduate studies in the Department of Chemistry of the Moscow State University, and earned his...
0
Organic Chemistry
He briefly taught physical chemistry at the London University before moving to Pakistan. Upon his return, he joined the Pakistan Atomic Energy Commission (PAEC) and took the professorship of nuclear chemistry at the Pakistan Institute of Nuclear Science and Technology (PINSTECH). Subsequently, he joined the clandestine...
7
Physical Chemistry
* Weber et al. 2005 determined that the inactive X-chromosome in females is hypermethylated on a chromosome wide level using MeDIP coupled with microarray. * Keshet et al. 2006 performed a study on colon and prostate cancer cells using MeDIP-chip. The result is a genome-wide analysis of genes lying in hypermethylated ...
1
Biochemistry
The structural changes that occur during 72-hour hypothermic storage of previously uninjured kidneys have been described by Mackay who showed how there was progressive vacuolation of the cytoplasm of the cells which particularly affected the proximal tubules. On electron microscopy the mitochondria were seen to become ...
1
Biochemistry
SLS has been proposed as a potentially effective topical microbicide, for intravaginal use, to inhibit and possibly prevent infection by various enveloped and non-enveloped viruses such as the herpes simplex viruses, HIV, and the Semliki Forest virus. Liquid membranes formed from SDS in water have been demonstrated to ...
1
Biochemistry
In general, prehistoric extraction of metals, particularly copper, involved two fundamental stages: first, the smelting of copper ore at temperatures exceeding 700 °C is needed to separate the gangue from the copper; second, melting the copper, which requires temperatures exceeding its melting point of 1080 °C. Given t...
8
Metallurgy
The use of equivalent weights in general chemistry has largely been superseded by the use of molar masses. Equivalent weights may be calculated from molar masses if the chemistry of the substance is well known: *sulfuric acid has a molar mass of 98.078(5) , and supplies two moles of hydrogen ions per mole of sulfuric a...
7
Physical Chemistry
Crucibles used for copper smelting were generally wide shallow vessels made from clay that lacks refractory properties which is similar to the types of clay used in other ceramics of the time. During the Chalcolithic period, crucibles were heated from the top by using blowpipes. Ceramic crucibles from this time had sli...
3
Analytical Chemistry
In Europe, the Water Framework Directive (WFD) went into effect on October 23, 2000. It requires all EU member states to show that all surface and groundwater bodies are in good status. The WFD requires member states to implement monitoring systems to estimate the integrity of biological stream components for specific...
2
Environmental Chemistry
The Barbier–Wieland degradation is a procedure for shortening the carbon chain of a carboxylic acid by one carbon. It only works when the carbon adjacent to the carboxyl is a simple methylene bridge (an aliphatic carbon with no substituents). The reaction sequence involves conversion of the carboxyl and alpha carbon in...
0
Organic Chemistry
Some forms of mutations are hereditary (germline mutations), or passed on from a parent to its offspring. Such mutated coding regions are present in all cells within the organism. Other forms of mutations are acquired (somatic mutations) during an organisms lifetime, and may not be constant cell-to-cell. These changes ...
1
Biochemistry
The Hoopes process is a metallurgical process, used to obtain aluminium metal of very high purity (about 99.99% pure). The process was patented by William Hoopes, a chemist of the Aluminum Company of America (ALCOA), in 1925.
8
Metallurgy
The radio spectrum scope (also radio panoramic receiver, panoramic adapter, pan receiver, pan adapter, panadapter, panoramic radio spectroscope, panoramoscope, panalyzor and band scope) was invented by Marcel Wallace - and measures and shows the magnitude of an input signal versus frequency within one or more radio ban...
7
Physical Chemistry
Metal carbonyls are used in a number of industrially important carbonylation reactions. In the oxo process, an alkene, hydrogen gas, and carbon monoxide react together with a catalyst (such as dicobalt octacarbonyl) to give aldehydes. Illustrative is the production of butyraldehyde from propylene: :CHCH=CH + H + CO → C...
0
Organic Chemistry
The glyoxylate cycle uses five of the eight enzymes associated with the tricarboxylic acid cycle: citrate synthase, aconitase, succinate dehydrogenase, fumarase, and malate dehydrogenase. The two cycles differ in that in the glyoxylate cycle, isocitrate is converted into glyoxylate and succinate by isocitrate lyase (IC...
1
Biochemistry
Electrophilic amination is a chemical process involving the formation of a carbon–nitrogen bond through the reaction of a nucleophilic carbanion with an electrophilic source of nitrogen.
0
Organic Chemistry
Mesembrine was first isolated and characterized by Bodendorf, et al. in 1957. It is a tricyclic molecule and has two bridgehead chiral carbons between the five-membered ring and the six-membered ring (highlighted in green in the figure below). Because of its structure and bioactivity, mesembrine has been a target for t...
0
Organic Chemistry
Thymidylate synthase inhibitors are chemical agents which inhibit the enzyme thymidylate synthase and have potential as an anticancer chemotherapy. This inhibition prevents the methylation of C5 of deoxyuridine monophosphate (dUMP) thereby inhibiting the synthesis of deoxythymidine monophosphate (dTMP). The downstream...
1
Biochemistry
Abiotic sources of hydrogen gas include water-rock and photochemical reactions. Exothermic serpentinization reactions between water and olivine minerals produce H in the marine or terrestrial subsurface. In the ocean, hydrothermal vents erupt magma and altered seawater fluids including abundant H, depending on the temp...
1
Biochemistry
In order to conduct DNA separation by silica adsorption, a sample (this may be anything from purified cells to a tissue specimen) is lysed, releasing proteins, DNA, phospholipids, etc. from the cells. The remaining tissue is discarded. The supernatant containing the DNA is then exposed to silica in a solution with high...
1
Biochemistry
Plants secrete a variety of chemicals to help seal off damaged areas. For example, the grape vine Vitis vinifera is able to block the xylem water-transport tubes in its stems using the chemical tylose in summertime, and gels in wintertime when the plant is dormant. Tylose helps to prevent pathogens such as wood-rottin...
1
Biochemistry
A J-aggregate is a type of dye with an absorption band that shifts to a longer wavelength (bathochromic shift) of increasing sharpness (higher absorption coefficient) when it aggregates under the influence of a solvent or additive or concentration as a result of supramolecular self-organisation. The dye can be characte...
6
Supramolecular Chemistry
Deficiency of expression of a DNA repair gene occurs in many cancers (see DNA repair defect and cancer risk and microRNA and DNA repair). Altered microRNA (miRNA) expression that either decreases accurate DNA repair or increases inaccurate microhomology-mediated end joining (MMEJ) DNA repair is often observed in cance...
1
Biochemistry
One of the important factors in determining the dentinal bonding is collagen. When dentin is etched, smear layer and minerals from dentinal structure will be removed, hence exposing the collagen fibres. The areas where the minerals are removed are filled with water which functions as plasticizer for collagen and keeps ...
7
Physical Chemistry
The expressome is a supramolecular complex consisting of RNA polymerase and a trailing ribosome linked by a shared mRNA transcript. It is supported by the transcription factors NusG and NusA, which interact with both RNA polymerase and the ribosome to couple the complexes together. When coupled by transcription factor ...
1
Biochemistry
Major studies in which knockout of particular amino acids was achieved in the CTD have been carried out. The results indicate that RNA polymerase II CTD truncation mutations affect the ability to induce transcription of a subset of genes in vivo, and the lack of response to induction maps to the upstream activating seq...
1
Biochemistry
Coenzymes Q is a coenzyme family that is ubiquitous in animals and many Pseudomonadota, a group of gram-negative bacteria. The fact that the coenzyme is ubiquitous gives the origin of its other name, ubiquinone. In humans, the most common form of coenzymes Q is coenzyme Q, also called CoQ () or ubiquinone-10. Coenzyme ...
1
Biochemistry
The dehydration theory explains why mucoadhesion can arise rapidly. When two gels capable of rapid gelation in an aqueous environment are brought into contact, movement occurs between the two gels until a state of equilibrium is reached. Gels associated with a strong affinity for water will have high osmotic pressures ...
1
Biochemistry
In coordination chemistry, a stability constant (also called formation constant or binding constant) is an equilibrium constant for the formation of a complex in solution. It is a measure of the strength of the interaction between the reagents that come together to form the complex. There are two main kinds of complex:...
7
Physical Chemistry
Selegiline has an oral bioavailability of about 10%, which increases when ingested together with a fatty meal, as the molecule is fat soluble. Selegiline and its metabolites bind extensively to plasma proteins (at a rate of 94%). They cross the blood–brain barrier and enter the brain, where they most concentrated at th...
4
Stereochemistry
Diazo compounds were first produced by Peter Griess who had discovered a versatile new chemical reaction, as detailed in his 1858 paper "Preliminary notice on the influence of nitrous acid on aminonitro- and aminodinitrophenol."
0
Organic Chemistry
Proline-, glutamic acid- and leucine-rich protein 1 (PELP1) also known as modulator of non-genomic activity of estrogen receptor (MNAR) and transcription factor HMX3 is a protein that in humans is encoded by the PELP1 gene. is a transcriptional corepressor for nuclear receptors such as glucocorticoid receptors and a co...
1
Biochemistry
Chayen is best known for her invention of novel protein crystallization methods. In 1990, she first published a method of suspending droplets of protein solution and precipitant solutions in low-density paraffin oil to prevent evaporation during the microbatch crystallization process. The microbatch process can be suit...
1
Biochemistry
Atmospheric optics ray tracing codes - this article list codes for light scattering using ray-tracing technique to study atmospheric optics phenomena such as rainbows and halos. Such particles can be large raindrops or hexagonal ice crystals. Such codes are one of many approaches to calculations of light scattering b...
7
Physical Chemistry
Hazardous materials are often carried in pipelines and thus their structural integrity is of paramount importance. Corrosion of a pipeline can thus have grave consequences. One of the methods used to control pipeline corrosion is by the use of Fusion bonded epoxy coatings. DCVG is used to monitor it. Impressed current...
8
Metallurgy
The plot reveals whether hydrophobic amino acids are concentrated on one side of the helix, usually with polar or hydrophilic amino acids on the other. This arrangement is common in alpha helices within globular proteins, where one face of the helix is oriented toward the hydrophobic core and one face is oriented towar...
1
Biochemistry
Lysophosphatidylinositol (LPI, lysoPI), or -α-lysophosphatidylinositol, is an endogenous lysophospholipid and endocannabinoid neurotransmitter. LPI, along with its 2-arachidonoyl- derivative, 2-arachidonoyl lysophosphatidylinositol (2-ALPI), have been proposed as the endogenous ligands of GPR55.
1
Biochemistry
Although most experiments use cellular response as a measure of the effect, the effect is, in essence, a result of the binding kinetics; so, in order to illustrate the mechanism, ligand binding is used. A ligand A will bind to a receptor R according to an equilibrium constant : Although the equilibrium constant is more...
1
Biochemistry
Chirality is not limited to carbon atoms, though carbon atoms are often centers of chirality due to their ubiquity in organic chemistry. Nitrogen and phosphorus atoms can also form bonds in a tetrahedral configuration. A nitrogen in an amine may be a stereocenter if all three groups attached are different because the e...
4
Stereochemistry
One example of imbibition in nature is the absorption of water by hydrophilic colloids. Matrix potential contributes significantly to water in such substances. Dry seeds germinate in part by imbibition. Imbibition can also control circadian rhythms in Arabidopsis thaliana and (probably) other plants. The Amott test em...
7
Physical Chemistry
Force spectroscopy is used in biophysics to measure the mechanical properties of living material (such as tissue or cells) or detect structures of different stiffness buried into the bulk of the sample using the stiffness tomography. Another application was to measure the interaction forces between from one hand a mate...
6
Supramolecular Chemistry
The rate of substrate utilization is related to the specific growth rate as where : X is the total biomass (since the specific growth rate μ is normalized to the total biomass), : Y is the yield coefficient. r is negative by convention. In some applications, several terms of the form [S] / (K + [S]) are multiplied toge...
7
Physical Chemistry
The flow cells are connected to a display and/or recorder. On older systems this was a simple chart recorder, on modern systems a computer with hardware interface and display is used. This permits the experimenter to identify when peaks in protein concentration occur, indicating that specific components of the mixture ...
3
Analytical Chemistry
Although there were some studies that showed an inverse correlation between serum bilirubin level and prevalences of ischemic coronary artery disease, cancer mortality, or colorectal cancer in general population, the potential benefits of the chemopreventive function of bilirubin and their causative relations haven't b...
1
Biochemistry
Polymer melts exhibit different deformation mechanisms when subjected to shear or tensile stresses. For example, a polymer melt’s ductility can increase when a stimulus, such as light, causes fragmentation of the polymer chains through bond breaking. This process is known as chain scission. In the low temperature regim...
8
Metallurgy
The nature of chemical reactions and their description is one of the most fundamental problems in chemistry. The concepts of covalent and ionic bonds which emerged in the beginning of the 20th century specify the profound differences between their electronic structures. These differences, in turn, lead to dramatically ...
1
Biochemistry
The primary commercial use of dimethyl methylphosphonate is as a flame retardant. Other commercial uses are a preignition additive for gasoline, anti-foaming agent, plasticizer, stabilizer, textile conditioner, antistatic agent, and an additive for solvents and low-temperature hydraulic fluids. It can be used as a cata...
1
Biochemistry
Generally this topic is discussed when covering tandem mass spectrometry fragmentation and occurs generally by the same mechanisms. For example, of a mechanism of alpha-cleavage, an electron is knocked off an atom (usually by electron collision) to form a radical cation. Electron removal generally happens in the follow...
0
Organic Chemistry
Biuret is also used as a non-protein nitrogen source in ruminant feed, where it is converted into protein by gut microorganisms. It is less favored than urea, due to its higher cost and lower digestibility but the latter characteristic also slows down its digestion and so decreases the risk of ammonia toxicity.
0
Organic Chemistry
The funeral was large. The newspapers carried tributes and subsequently lengthier obituaries from learned societies were published, such as that in the Australian Medical Journal and elsewhere. The Melbourne Leader described the funeral: "The coffin was drawn by four horses. Four mourning coaches contained the chief mo...
3
Analytical Chemistry
Convection (or convective heat transfer) is the transfer of heat from one place to another due to the movement of fluid. Although often discussed as a distinct method of heat transfer, convective heat transfer involves the combined processes of conduction (heat diffusion) and advection (heat transfer by bulk fluid flow...
7
Physical Chemistry
The mechanistic study of the palladium-catalyzed meta-selective C–H bond activation with a nitrile-containing template was done by Yu, Wu, Houk and their co-workers. The DFT calculations suggest that the regioselectivity is achieved in the C–H activation step, which is the rate-determining step. It proceeds via a conce...
0
Organic Chemistry
Anion (−) and cation (+) indicate the net electric charge on an ion. An ion that has more electrons than protons, giving it a net negative charge, is named an anion, and a minus indication "Anion (−)" indicates the negative charge. With a cation it is just the opposite: it has fewer electrons than protons, giving it a ...
7
Physical Chemistry
Nitric acid has been used in various forms as the oxidizer in liquid-fueled rockets. These forms include red fuming nitric acid, white fuming nitric acid, mixtures with sulfuric acid, and these forms with HF inhibitor. IRFNA (inhibited red fuming nitric acid) was one of three liquid fuel components for the BOMARC missi...
3
Analytical Chemistry
The addition of certain alloying elements, such as manganese and nickel, can stabilize the austenitic structure, facilitating heat-treatment of low-alloy steels. In the extreme case of austenitic stainless steel, much higher alloy content makes this structure stable even at room temperature. On the other hand, such el...
8
Metallurgy