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With the lone exception of the bis(trifluoromethyl) derivative, the dominant reaction of phosphinous acids is tautomerization:
:PROH → OPRH
Even the pentafluorophenyl compound P(CF)OH is unstable with respect to the phosphine oxide.
Although phosphinous acids are rare, their P-bonded coordination complexes are well e... | 0 | Organic Chemistry |
Suppose an alloy at an equilibrium temperature T consists of mass fraction of element B. Suppose also that at temperature T the alloy consists of two phases, α and β, for which the α consists of , and β consists of . Let the mass of the α phase in the alloy be so that the mass of the β phase is , where is the tota... | 8 | Metallurgy |
Eukaryotic genomes have distinct higher-order chromatin structures that are closely packaged functional relates to gene expression. Chromatin compresses the genome to fit into the cell nucleus, while still ensuring that the gene can be accessed when needed, such as during gene transcription, replication, and DNA repair... | 1 | Biochemistry |
The thermal pressure of a crystal defines how the unit-cell parameters change as a function of pressure and temperature. Therefore, it also controls how the cell parameters change along an isochore, namely as a function of . Usually, Mie-Grüneisen-Debye and other Quasi harmonic approximation (QHA) based state functions... | 7 | Physical Chemistry |
Once an attosecond light source is available, one has to drive the pulse towards the sample of interest and, then, measure its dynamics.
The most suitable experimental observables to analyze the electron dynamics in matter are:
* Angular asymmetry in the velocity distribution of molecular photo-fragment.
* Quantum yiel... | 7 | Physical Chemistry |
Dioxirane epoxidation is highly versatile, and compares favorably to related peracid oxidations in many respects. Peracids generate acidic byproducts, meaning that acid-labile substrates and products must be avoided. Dioxirane epoxidations using isolated oxidant can be carried out under neutral conditions without the n... | 0 | Organic Chemistry |
Evans and his co-workers has developed a strategy that relies heavily on asymmetric aldol methodology for the production of the polypropionate backbone. They used a Claisen condensation reaction to construct the C(13)–C(14) trisubstituted Z-olefin. The Evans synthesis of (+)-discodermolide has an overall yield of 6.4%... | 0 | Organic Chemistry |
Targets of (p)ppGpp include rRNA operons, of which there are seven in E.coli, all of which have 2 promoters. When (p)ppGpp associates with the promoter it affects the RNA polymerase enzyme's ability to bind and initiate transcription. It is thought that (p)ppGpp may affect the stability of the open complex formed by RN... | 1 | Biochemistry |
Diisopinocampheylborane was originally prepared by hydroboration of excess α-pinene with borane,
but it is now more commonly generated from borane-methyl sulfide (BMS).
The compound can be isolated as a solid, but because it is quite sensitive to water and air, it is often generated in situ and used as a solution. Th... | 0 | Organic Chemistry |
A dihedral angle is the angle between two intersecting planes or half-planes. In chemistry, it is the clockwise angle between half-planes through two sets of three atoms, having two atoms in common. In solid geometry, it is defined as the union of a line and two half-planes that have this line as a common edge. In hig... | 4 | Stereochemistry |
When energetic ions collide with atoms of a target material, an exchange of momentum takes place between them.
These ions, known as "incident ions", set off collision cascades in the target. Such cascades can take many paths; some recoil back toward the surface of the target. If a collision cascade reaches the surface ... | 7 | Physical Chemistry |
The inductive effect can be used to determine the stability of a molecule depending on the charge present on the atom and the groups bonded to the atom. For example, if an atom has a positive charge and is attached to a -I group its charge becomes amplified and the molecule becomes more unstable. Similarly, if an atom ... | 7 | Physical Chemistry |
Shen Kuo's written work of 1088 contains, among other early descriptions of inventions, a method of repeated forging of cast iron under a cold blast similar to the modern Bessemer process.
Chinese metallurgy was widely practiced during the Middle Ages; during the 11th century, the growth of the iron industry caused vas... | 8 | Metallurgy |
TLE uses continuous-wave lasers (typically with a wavelength of around 1000 nm) located outside the vacuum chamber to heat sources of material in order to generate a flux of vapor via evaporation or sublimation. Owing to the localized nature of the heat induced by the laser, a portion of the source may be transformed i... | 3 | Analytical Chemistry |
A recent trend is to change the method by which the skimmer is fed dirty water from the aquarium as a means to recirculate water within the skimmer multiple times before it is returned to the sump or the aquarium. Aspirating pump skimmers are the most popular type of skimmer to use recirculating designs although other ... | 3 | Analytical Chemistry |
During the development of B cells, the immunoglobulin gene undergoes sequences of rearrangements that lead to formation of the antibody repertoire. For example, in the lymphoid cell, a partial rearrangement of the heavy-chain gene occurs which is followed by complete rearrangement of heavy-chain gene. Here at this stag... | 1 | Biochemistry |
The term "bootstrap model" is used for a class of theories that use very general consistency criteria to determine the form of a quantum theory from some assumptions on the spectrum of particles. It is a form of S-matrix theory. | 7 | Physical Chemistry |
For solutions, a slightly different equation is used:
In this equation, α (Greek letter "alpha") is the measured rotation in degrees, l is the path length in decimeters, c is the concentration in g/mL, T is the temperature at which the measurement was taken (in degrees Celsius), and λ is the wavelength in nanometers.
F... | 4 | Stereochemistry |
The National Research Council's 2006 report emphasized that accurate communication of results is essential for the proper use of biomonitoring surveys, but at the same time noted "there is no accepted standard for good biomonitoring communications." In 2007, the Boston University School of Public Health organized a pan... | 2 | Environmental Chemistry |
Even for systems where only light of optimal wavelengths is passed to the photovoltaic converter, inefficiencies associated with non-radiative recombination and Ohmic losses exist. There are also losses from Fresnel reflections at the PV surface, optimal-wavelength light that passes through the cell unabsorbed, and the... | 7 | Physical Chemistry |
Evans took a postdoctoral fellowship at the University of Texas at Arlington for the 1970–1971 academic year, followed by second fellowship at the University of Notre Dame in Indiana, where he worked with the organic chemist Ernest L. Eliel studying stereochemistry. Upon the completion of the fellowship, he was invited... | 4 | Stereochemistry |
DMDO is most commonly used for the oxidation of alkenes to epoxides. One advantage of using DMDO is that the only byproduct of oxidation is acetone, a fairly innocuous and volatile compound. DMDO oxidations are particularly mild, sometimes allowing oxidations which might not otherwise be possible.
Despite its high re... | 0 | Organic Chemistry |
Creatinine (; from Ancient Greek: κρέας (kréas) flesh) is a breakdown product of creatine phosphate from muscle and protein metabolism. It is released at a constant rate by the body (depending on muscle mass). | 1 | Biochemistry |
For laboratory use, the N-alkylation reaction is often unselective. A variety of alternative methods have been developed, such as the Delépine reaction, which uses hexamine. The Gabriel synthesis, involving the use of an equivalent to NH, only applies to primary alkyl halides. | 0 | Organic Chemistry |
Linear expansion means change in one dimension (length) as opposed to change in volume (volumetric expansion).
To a first approximation, the change in length measurements of an object due to thermal expansion is related to temperature change by a coefficient of linear thermal expansion (CLTE). It is the fractional chan... | 7 | Physical Chemistry |
Concerted metalation-deprotonation (CMD) is a mechanistic pathway through which transition-metal catalyzed C–H activation reactions can take place. In a CMD pathway, the C–H bond of the substrate is cleaved and the new C–Metal bond forms through a single transition state. This process does not go through a metal specie... | 0 | Organic Chemistry |
Charles Moureu attended school in Bayonne. At 17, he apprenticed with his older brother, Félix Moureu, in his brother's pharmacy in Biarritz, in preparation for studies in pharmacy.
From 1884 to 1891 Moureu studied at the École Supérieure de Pharmacie in Paris. He received the school's silver medal in 1886, and both it... | 0 | Organic Chemistry |
ITC is a quantitative technique that can determine the binding affinity (), reaction enthalpy (), and binding stoichiometry () of the interaction between two or more molecules in solution. This is achieved by measuring the enthalpies of a series of binding reactions caused by injections of a solution of one molecule to... | 7 | Physical Chemistry |
Early diagnosis and analysis of seemingly healthy concrete cover and reinforcement status allows pre-emptive corrosion control measures to reduce unwanted risks to structural safety. Bundesanstalt für Materialforschung und -prüfung (Federal Institute for Materials Research and Testing, Germany) has developed a sensor e... | 8 | Metallurgy |
The Laves graph is a cubic graph, meaning that there are exactly three edges at each vertex. Every pair of a vertex and adjacent edge can be transformed into every other such pair by a symmetry of the graph, so it is a symmetric graph. More strongly, for every two vertices and , every one-to-one correspondence between... | 3 | Analytical Chemistry |
The activity coefficient , which is also a dimensionless quantity, relates the activity to a measured mole fraction (or in the gas phase), molality , mass fraction , molar concentration (molarity) or mass concentration :
The division by the standard molality (usually 1 mol/kg) or the standard molar concentration ... | 7 | Physical Chemistry |
Lithotrophic microbes are responsible for the phenomenon known as acid mine drainage. Typically occurring in mining areas, this process concerns the active metabolism of pyrites and other reduced sulfur components to sulfate. One example is the acidophilic bacterial genus, A. ferrooxidans, that use iron(II) sulfide (Fe... | 1 | Biochemistry |
Like all chemical reactions, the unimolecular decomposition of ions is subject to thermodynamic versus kinetic reaction control: the kinetic product forms faster, whereas the thermodynamic product is more stable. In the decomposition of ABCD, the reaction to form AD is thermodynamically favored and the reaction to f... | 7 | Physical Chemistry |
A variety of cleavage agents can be chosen. a desirable agent is one that is sequence neutral, easy to use, and is easy to control. Unfortunately no available agents meet all of these standards, so an appropriate agent can be chosen, depending on your DNA sequence and ligand of interest. The following cleavage agen... | 1 | Biochemistry |
Metamerism, in chemistry, is used to define the isomeric relationship between compounds with the same polyvalent functional group with heteroatom but differ in the main carbon chain or any of the side chains. It has rather been an obsolete term for isomerism, which has not been recognised by IUPAC in its publications. ... | 4 | Stereochemistry |
Elasticities coefficient can also be computed numerically, something that is often done in simulation software.
For example, a small change (say 5%) can be made to the chosen reactant concentration, and the change in the reaction rate recorded. To illustrate this, assume that the reference reaction rate is , and the re... | 7 | Physical Chemistry |
Although there are many diverse pathogens, many of which are constantly mutating, it is a surprise that a majority of individuals remain free of infections. Thus, maintenance of health requires the body to recognize all pathogens (antigens they present or produce) likely to exist. This is achieved by maintaining a pool... | 1 | Biochemistry |
Artificial gene synthesis, or simply gene synthesis, refers to a group of methods that are used in synthetic biology to construct and assemble genes from nucleotides de novo. Unlike DNA synthesis in living cells, artificial gene synthesis does not require template DNA, allowing virtually any DNA sequence to be synthesi... | 1 | Biochemistry |
Photonic crystals allow precise control of electromagnetic wave properties. These materials give rise to the photonic bandgap (PBG). In the spectral range of the PBG, electromagnetic waves cannot propagate. Engineering these materials allows some ability to tailor their emission and absorption properties, allowing for ... | 7 | Physical Chemistry |
The Michaelis–Becker reaction is the reaction of a hydrogen phosphonate with a base, followed by a nucleophilic substitution of phosphorus on a haloalkane, to give an alkyl phosphonate. Yields of this reaction are often lower than the corresponding Michaelis–Arbuzov reaction. | 0 | Organic Chemistry |
Accessory pigments are light-absorbing compounds, found in photosynthetic organisms, that work in conjunction with chlorophyll a. They include other forms of this pigment, such as chlorophyll b in green algal and vascular ("higher") plant antennae, while other algae may contain chlorophyll c or d. In addition, there ar... | 5 | Photochemistry |
;Cryosurgical systems
A number of medical supply companies have developed cryogen delivery systems for cryosurgery. Most are based on the use of liquid nitrogen, although some employ the use of proprietary mixtures of gases that combine to form the cryogen. | 1 | Biochemistry |
In chemistry, functionality is the presence of functional groups in a molecule. A monofunctional molecule possesses one functional group, a bifunctional (or difunctional) two, a trifunctional three, and so forth. In organic chemistry (and other fields of chemistry), a molecule's functionality has a decisive influence o... | 0 | Organic Chemistry |
In February 1862, Lord Kelvin used the existence of the Sun and the stars as an empirical proof that the universe has not achieved thermodynamic equilibrium, as entropy production and free work are still possible, and there are temperature differences between objects. Helmholtz and Rankine expanded Kelvin's work soon a... | 7 | Physical Chemistry |
The process of transcriptional termination is less understood in eukaryotes, which have extensive post-transcriptional RNA processing, and each of the three types of eukaryotic RNA polymerase have a different termination system.
In RNA polymerase I, Transcription termination factor, RNA polymerase I binds downstream of... | 1 | Biochemistry |
Eukaryotic photoautotrophs include red algae, haptophytes, stramenopiles, cryptophytes, chlorophytes, and land plants. These organisms perform photosynthesis through organelles called chloroplasts and are believed to have originated about 2 billion years ago. Comparing the genes of chloroplast and cyanobacteria strongl... | 5 | Photochemistry |
A "strong" ion exchanger will not lose the charge on its matrix once the column is equilibrated and so a wide range of pH buffers can be used. "Weak" ion exchangers have a range of pH values in which they will maintain their charge. If the pH of the buffer used for a weak ion exchange column goes out of the capacity ra... | 3 | Analytical Chemistry |
Thin-layer chromatography (TLC) is a chromatography technique that separates components in non-volatile mixtures.
It is performed on a TLC plate made up of a non-reactive solid coated with a thin layer of adsorbent material. This is called the stationary phase. The sample is deposited on the plate, which is eluted with... | 3 | Analytical Chemistry |
Polarity also has an effect on allylic strain. In terms of stereoselectivity, polar groups act like large, bulky groups. Even though two groups may have approximately the same A values the polar group will act as though it were much bulkier. This is due to the donor character of the polar group. Polar groups increase ... | 4 | Stereochemistry |
Current trends in organic chemistry include (as of 2020):
*Biocatalysis
*Catalysis
*Chemosensors
*Chiral synthesis
* Flow chemistry
* Green chemistry
*Mechanochemistry
*Photoredox catalysis | 0 | Organic Chemistry |
By the time Loewi began his experiments there was much discussion among scientists whether communication between nerves and muscles was chemical or electrical by nature. Experiments by Luigi Galvani in the 18th century had demonstrated that electrical stimulation of the frog sciatic nerve resulted in twitching of the l... | 1 | Biochemistry |
Under homeostasis, the reactivity of heme is controlled by its insertion into the "heme pockets" of hemoproteins. Under oxidative stress however, some hemoproteins, e.g. hemoglobin, can release their heme prosthetic groups. The non-protein-bound (free) heme produced in this manner becomes highly cytotoxic, most probabl... | 1 | Biochemistry |
The isotopic composition of the components in a biochemical system can be defined in different ways depending on the definition of isotopic ratio. Three definitions are described here: | 7 | Physical Chemistry |
Cyanosulfidic chemistry has several limitations. While the products are all formed from the same starting materials, many of the reactions require the periodic delivery of new reagents which complicates the syntheses. The chemical synthesis is therefore not truly “one-pot” chemistry which would require all reactants to... | 9 | Geochemistry |
L-(+)-tartaric acid, can participate in several reactions. As shown the reaction scheme below, dihydroxymaleic acid is produced upon treatment of L-(+)-tartaric acid with hydrogen peroxide in the presence of a ferrous salt.
:HOCCH(OH)CH(OH)COH + HO → HOCC(OH)C(OH)COH + 2 HO
Dihydroxymaleic acid can then be oxidized to ... | 4 | Stereochemistry |
For molecular biology research different types of markers may be used based on the selection sought. These include:
*Positive or selection markers are selectable markers that confer selective advantage to the host organism. An example would be antibiotic resistance, which allows the host organism to survive antibiotic ... | 1 | Biochemistry |
A disadvantage of AFM compared with the scanning electron microscope (SEM) is the single scan image size. In one pass, the SEM can image an area on the order of square millimeters with a depth of field on the order of millimeters, whereas the AFM can only image a maximum scanning area of about 150×150 micrometers and a... | 6 | Supramolecular Chemistry |
A Soxhlet extractor is a piece of laboratory apparatus invented in 1879 by Franz von Soxhlet. It was originally designed for the extraction of a lipid from a solid material. Typically, Soxhlet extraction is used when the desired compound has a limited solubility in a solvent, and the impurity is insoluble in that sol... | 3 | Analytical Chemistry |
Azlocillin is considered a broad spectrum antibiotic and can be used against a number of Gram positive and Gram negative bacteria. The following represents MIC susceptibility data for a few medically significant organisms.
* Escherichia coli 1 μg/mL – 32 μg/mL
* Haemophilus spp. 0.03 μg/mL – 2 μg/mL
* Pseudomonas aerug... | 4 | Stereochemistry |
* Sodium: 15 mmol/L
* Potassium: 9 mmol/L
* Magnesium: 4 mmol/L
* Calcium: 0.015 mmol/L
* Ketoglutarate/glutamic acid: 1 mmol/L
* Histidine: 198 mmol/L
* Mannitol: 30 mmol/L
* Tryptophan: 2 mmol/L | 1 | Biochemistry |
The formation of a complex between a metal ion, M, and a ligand, L, is in fact usually a substitution reaction. For example, in aqueous solutions, metal ions will be present as aqua ions, so the reaction for the formation of the first complex could be written as
The equilibrium constant for this reaction is given by
[L... | 7 | Physical Chemistry |
Dye completed a Bachelor of Arts degree in Natural Sciences in 1997 at the University of Cambridge, followed by a PhD on the Mechanical effects of welding superalloys in 2000, supervised by Roger Reed. | 8 | Metallurgy |
Common side effects include rash, loss of appetite, nausea, diarrhea, and low blood white blood cell levels. Other serious side effects include liver problems, obliterative bronchiolitis, and myasthenia gravis. It is not recommended in people with lupus erythematosus. Use during pregnancy may result in harm to the baby... | 4 | Stereochemistry |
A glow discharge is a plasma formed by the passage of electric current through a gas. It is often created by applying a voltage between two electrodes in a glass tube containing a low-pressure gas. When the voltage exceeds a value called the striking voltage, the gas ionization becomes self-sustaining, and the tube glo... | 3 | Analytical Chemistry |
A large group of organocatalysts incorporate the urea or the thiourea moiety. These catalytically effective (thio)urea derivatives termed (thio)urea organocatalysts provide explicit double hydrogen-bonding interactions to coordinate and activate H-bond accepting substrates.
Their current uses are restricted to asymmetr... | 0 | Organic Chemistry |
A thermal diode in this sense is a device whose thermal resistance is different for heat flow in one direction than for heat flow in the other direction. I.e., when the thermal diode's first terminal is hotter than the second, heat will flow easily from the first to the second, but when the second terminal is hotter th... | 7 | Physical Chemistry |
Its name is derived from the word “pigment” (P) and the presence of a major bleaching band centered around 695-700 nm in the flash-induced absorbance difference spectra of P700/ P700+•. | 5 | Photochemistry |
Importantly, the rate of change in ocean acidification is much higher than in the geological past. This faster change prevents organisms from gradually adapting, and prevents climate cycle feedbacks from kicking in to mitigate ocean acidification. Ocean acidification is now on a path to reach lower pH levels than at an... | 9 | Geochemistry |
The combined RT-PCR and qPCR technique has been described as quantitative RT-PCR or real-time RT-PCR (sometimes even called quantitative real-time RT-PCR), has been variously abbreviated as qRT-PCR, RT-qPCR, RRT-PCR, and rRT-PCR. In order to avoid confusion, the following abbreviations will be used consistently throug... | 1 | Biochemistry |
Scheme 1 shows the synthesis of the oxetane D ring from the C ring starting from the (+) enantiomer of the Wieland-Miescher ketone (1). Reduction of this diketone with sodium borohydride provided unsaturated ketoalcohol 2, which was protected as an acetate. Formation of the ketal was accompanied by alkene rearrangement... | 0 | Organic Chemistry |
The karyorelictid nuclear code (translation table 27) is a genetic code used by the nuclear genome of the Karyorelictea ciliate Parduczia sp. This code, along with translation tables 28 and 31, is remarkable in that every one of the 64 possible codons can be a sense codon. Translation termination probably relies on con... | 1 | Biochemistry |
Respiratory, allergic, or immune effects in infants or children are associated with man-made VOCs and other indoor or outdoor air pollutants.
Some VOCs, such as styrene and limonene, can react with nitrogen oxides or with ozone to produce new oxidation products and secondary aerosols, which can cause sensory irritation... | 0 | Organic Chemistry |
The Overlapping distribution method was introduced by Charles H. Bennett for estimating chemical potential. | 7 | Physical Chemistry |
The eigenstate thermalization hypothesis (or ETH) is a set of ideas which purports to explain when and why an isolated quantum mechanical system can be accurately described using equilibrium statistical mechanics. In particular, it is devoted to understanding how systems which are initially prepared in far-from-equilib... | 7 | Physical Chemistry |
The triazine family of herbicides, which includes atrazine, was introduced in the 1950s; they have the current distinction of being the herbicide family of greatest concern regarding groundwater contamination. Atrazine does not break down readily (within a few weeks) after being applied to soils of above-neutral pH. Un... | 2 | Environmental Chemistry |
Typically FbFPs have an excitation maximum at a wavelength of approximately 450 nm (blue light) and a second distinct excitation peak around 370 nm (UV-A light). The main emission peak is at approx. 495 nm, with a shoulder around 520 nm. One variant of Pp2FbFP (Q116V) exhibits a 10 nm blue shift in both the excitation ... | 1 | Biochemistry |
The 1993 Keuhne synthesis concerns racemic strychnine. Starting compounds tryptamine 1 and 4,4-dimethoxy acrolein 2 were reacted together with boron trifluoride to acetal 3 as a single diastereomer in an amine-carbonyl condensation / sigmatropic rearrangement sequence.
Hydrolysis with perchloric acid afforded aldehyde ... | 0 | Organic Chemistry |
The technological features of FSL Kode constructs and the koding process can be summarized as follows:
* Rapid and simple – simple contact for 10–120 minutes and constructs spontaneously and stably incorporate – no washing required.
* Replicable – same variables (time, temperature, concentration) equals the same result... | 1 | Biochemistry |
In a multistep reaction, the rate-determining step does not necessarily correspond to the highest Gibbs energy on the reaction coordinate diagram. If there is a reaction intermediate whose energy is lower than the initial reactants, then the activation energy needed to pass through any subsequent transition state depen... | 7 | Physical Chemistry |
hair cell - half-life - halobacteria - halotolerance - haploid - heat of fusion - heat of vaporization - heat shock protein - Hsp70 (70 kDa heat shock proteins) - Hsp90 (90 kDa heat shock proteins) - heavy-chain immunoglobulin - Hela cell - helminth protein - helper T cell - hemopexin - hemoglobin - herpes simplex viru... | 1 | Biochemistry |
Radiation emitted by a moving source is subject to Doppler shift due to a finite line-of-sight velocity projection. If different parts of the emitting body have different velocities (along the line of sight), the resulting line will be broadened, with the line width proportional to the width of the velocity distributio... | 7 | Physical Chemistry |
Plants in temperate and polar regions adapt to winter and sub zero temperatures by relocating nutrients from leaves and shoots to storage organs. Freezing temperatures induce dehydrative stress on plants, as water absorption in the root and water transport in the plant decreases. Water in and between cells in the plant... | 1 | Biochemistry |
Abortive initiation is a normal process of transcription and occurs both in vitro and in vivo. After each nucleotide-addition step in initial transcription, RNA polymerase, stochastically, can proceed on the pathway toward promoter escape (productive initiation) or can release the RNA product and revert to the RNA pol... | 1 | Biochemistry |
Planar extension tests are carried out on thin specimens which are constrained from deforming in one direction. For planar extension in the directions with the direction constrained, the principal stretches are . From incompressibility . Hence .
Therefore,
The left Cauchy–Green deformation tensor can then be expre... | 7 | Physical Chemistry |
The Membership comprises almost 140 member companies in Europe as well as from the rest of the world. Members are:
* Coil coaters companies
* Paint, film and pre-treatment chemical suppliers
* Service centres/Stockholders
* Raw material suppliers
* Equipment manufacturers
* Technology providers
* Related associations/i... | 8 | Metallurgy |
Levetiracetam does not undergo extensive metabolism, and the metabolites formed are not active and do not exert pharmacological activity. Metabolism of levetiracetam is not by liver cytochrome P450 enzymes, but through other metabolic pathways such as hydrolysis and hydroxylation. | 4 | Stereochemistry |
Allyl complexes are often generated by oxidative addition of allylic halides to low-valent metal complexes. This route is used to prepare (allyl)NiCl:
:2 Ni(CO) + 2 ClCHCH=CH → Ni(μ-Cl)(η-CH) + 8 CO
A similar oxidative addition involves the reaction of allyl bromide to diiron nonacarbonyl. Oxidative addition route ha... | 0 | Organic Chemistry |
An induction period in chemical kinetics is an initial slow stage of a chemical reaction; after the induction period, the reaction accelerates. Ignoring induction periods can lead to runaway reactions.
In some catalytic reactions, a pre-catalyst needs to undergo a transformation to form the active catalyst, before the ... | 7 | Physical Chemistry |
In theory, any complexation reaction can be used as a volumetric technique provided that:
# The reaction reaches equilibrium rapidly after each portion of titrant is added.
# Interfering situations do not arise. For instance, the stepwise formation of several different complexes of the metal ion with the titrant, resu... | 3 | Analytical Chemistry |
Electroporation can also be used to help deliver drugs or genes into the cell by applying short and intense electric pulses that transiently permeabilize cell membrane, thus allowing transport of molecules otherwise not transported through a cellular membrane. This procedure is referred to as electrochemotherapy when t... | 1 | Biochemistry |
Methods to study interpolymer complexes could be classified into:
:(1) approaches to demonstrate the fact of the complex formation and to determine the composition of IPCs in solutions;
:(2) approaches to study the structure of IPCs formed;
:(3) methods to characterize IPCs in solid state. | 7 | Physical Chemistry |
Bronze disease is the chloride corrosion of cuprous (copper-based) artifacts. It was originally thought to be caused by bacteria. It is contagious in that the chlorides which cause it can spread the condition if they are brought into contact with another cuprous object. Despite its name, bronze disease can affect any c... | 8 | Metallurgy |
Biochemical receptors are large protein molecules that can be activated by the binding of a ligand such as a hormone or a drug. Receptors can be membrane-bound, as cell surface receptors, or inside the cell as intracellular receptors, such as nuclear receptors including those of the mitochondrion. Binding occurs as a r... | 1 | Biochemistry |
Continuing her interest in the f-elements, Soderholm shifted her focus from solid-state materials to nanoparticles and solutions, taking advantage of advances in X-ray structural probes made available by synchrotron facilities. Building on her earlier work using neutron scattering, her team became the first to discove... | 7 | Physical Chemistry |
A bond angle is the geometric angle between two adjacent bonds. Some common shapes of simple molecules include:
* Linear: In a linear model, atoms are connected in a straight line. The bond angles are set at 180°. For example, carbon dioxide and nitric oxide have a linear molecular shape.
* Trigonal planar: Molecules w... | 4 | Stereochemistry |
Protein adsorption influences the interactions that occur at the tissue-implant interface. Protein adsorption can lead to blood clots, the foreign-body response and ultimately the degradation of the device. In order to counter-act the effects of protein adsorption, implants are often coated with a polymer coating to de... | 7 | Physical Chemistry |
An example of a transversely isotropic material is the so-called on-axis unidirectional fiber composite lamina where the fibers are circular in cross section. In a unidirectional composite, the plane normal to the fiber direction can be considered as the isotropic plane, at long wavelengths (low frequencies) of excitat... | 3 | Analytical Chemistry |
Single crystal growth starts with a seed crystal that is used to template growth of a larger crystal. The overall process is lengthy, and machining is necessary after the single crystal is grown. | 8 | Metallurgy |
The Streptamer staining principle combines the classic method of T cell isolation by MHC-multimers with the Strep-tag/Strep-Tactin technology. The Strep-tag is a short peptide sequence that displays moderate binding affinity for the biotin-binding site of a mutated streptavidin molecule, called Strep-Tactin. For the St... | 1 | Biochemistry |
Robinson was an undergraduate student at the University of Cambridge, where she studied natural sciences. She moved to the University of Oxford for her graduate studies, where she investigated pleistocene climate chronology. After completing her doctorate, Robinson moved to California. She was appointed a postdoctoral... | 9 | Geochemistry |
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