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The vectors magnitude and direction is best understood when the dislocation-bearing crystal structure is first visualized without the dislocation, that is, the perfect crystal structure. In this perfect crystal structure, a rectangle whose lengths and widths are integer multiples of (the unit cell edge length) is draw... | 3 | Analytical Chemistry |
As of February 2016, the United States had no regulations governing mitochondrial donation, and Congress barred the FDA from evaluating any applications that involve implanting modified embryos into a woman.
The United Kingdom became the first country to legalize the procedure: the UK's chief medical officer recommende... | 1 | Biochemistry |
In most of its complexes, arenes bind in an η mode, with six nearly equidistant M-C bonds. The C-C-C angles are unperturbed vs the parent arene, but the C-C bonds are elongated by 0.2 Å. In the fullerene complex Ru(CO)(C), the fullerene binds to the triangular face of the cluster. | 0 | Organic Chemistry |
Joule heating is referred to as ohmic heating or resistive heating because of its relationship to Ohms Law. It forms the basis for the large number of practical applications involving electric heating. However, in applications where heating is an unwanted by-product of current use (e.g., load losses in electrical trans... | 7 | Physical Chemistry |
Carbon in the Earth's atmosphere exists in two main forms: carbon dioxide and methane. Both of these gases absorb and retain heat in the atmosphere and are partially responsible for the greenhouse effect. Methane produces a larger greenhouse effect per volume as compared to carbon dioxide, but it exists in much lower c... | 5 | Photochemistry |
Typical levels of beryllium that industries may release into the air are of the order of , averaged over a 30-day period, or of workroom air for an 8-hour work shift. Compliance with the current U.S. Occupational Safety and Health Administration (OSHA) permissible exposure limit for beryllium of has been determined t... | 1 | Biochemistry |
The purpose of this method is to reduce carbon content from steel. This process is suitable for secondary steelmaking industry which recycling steel scrap that has variety of carbon content in their feedstock. This method aim to replace current conventional method that utilizing Basic Oxygen Furnace (BOF) to reduce car... | 8 | Metallurgy |
The following example illustrates the potential of the photoacoustic technique: In the early 1970s, Patel and co-workers measured the temporal variation of the concentration of nitric oxide in the stratosphere at an altitude of 28 km with a balloon-borne photoacoustic detector. These measurements provided crucial data... | 7 | Physical Chemistry |
Haptophytes are similar and closely related to cryptophytes or heterokontophytes. Their chloroplasts lack a nucleomorph, their thylakoids are in stacks of three, and they synthesize chrysolaminarin sugar, which they store completely outside of the chloroplast, in the cytoplasm of the haptophyte. | 5 | Photochemistry |
* Noninvasive method for capturing mRNA from single cells in living, intact tissues for transcriptome analysis.
* Though other methods can be applied, such as laser capture microdissection and patch-pipette aspiration to isolate single cells, With TIVA Tags no damage to the cells and no tissue deformation from penetrat... | 1 | Biochemistry |
Expression of genes in mammals can be upregulated when signals are transmitted to the promoters associated with the genes. Cis-regulatory DNA sequences that are located in DNA regions distant from the promoters of genes can have very large effects on gene expression, with some genes undergoing up to 100-fold increased... | 1 | Biochemistry |
Organisms in all three domains of life, eukaryotes, bacteria and archaea, are able to carry out de novo biosynthesis of purines. This ability reflects the essentiality of purines for life. The biochemical pathway of synthesis is very similar in eukaryotes and bacterial species, but is more variable among archaeal spe... | 1 | Biochemistry |
The exact definition of spiciness is debated. Specifically, the orthogonality of the density with spiciness and the used scaling factor of potential temperature and salinity. McDougall claims that orthogonality should not be imposed because:
* There is no physical reason to impose orthogonality.
* Imposing orthogonal... | 7 | Physical Chemistry |
The BVS apparatus consists of a specimen surrounded by Helmholtz coils and isolated from external vibrations by a framework constructed from insulating foam and either lead or brass. The specimen is affixed with both a permanent magnet and a mirror. The orientation of the coils with respect to the magnet when a current... | 7 | Physical Chemistry |
The electric dipole moment of the dioxygen molecule, is zero, but the molecule is paramagnetic with two unpaired electrons so that there are magnetic-dipole allowed transitions which can be observed by microwave spectroscopy. The unit electron spin has three spatial orientations with respect to the given molecular rot... | 7 | Physical Chemistry |
* Antibiotics
** Actinomycin
** Bacitracin
** Calcium dependent antibiotic
** Daptomycin
** Vancomycin
** Teixobactin
** Tyrocidine
** Gramicidin
** Zwittermicin A
* Antibiotic precursors
** ACV-Tripeptide
* Cytostatics
** Epothilone
**Fabclavine
** Bleomycin
* Immunosuppressants
** Ciclosporin (Cyclosporine A)
* Sider... | 1 | Biochemistry |
Walsh diagrams were first introduced by A.D. Walsh, a British chemistry professor at the University of Dundee, in a series of ten papers in one issue of the Journal of the Chemical Society. Here, he aimed to rationalize the shapes adopted by polyatomic molecules in the ground state as well as in excited states, by app... | 7 | Physical Chemistry |
A Scuderi cycle is a thermodynamic cycle that is constructed out of the following series of thermodynamic processes:
* A-B and C-D (TOP and BOTTOM of the loop): a pair of quasi-parallel adiabatic processes
* D-A (LEFT side of the loop): a positively sloped, increasing pressure, increasing volume process
* B-C (RIGHT si... | 7 | Physical Chemistry |
Wetland chemistry is largely affected by dredging, which can be done for a variety of purposes. Wetlands are areas within floodplains with both terrestrial and aquatic characteristics, including marshes, swamps, bogs, and others. It has been estimated that they occupy around 2.8x10 km, about 2.2% of the Earth’s surface... | 9 | Geochemistry |
Concomitant or recent (previous fourteen days) monoamine oxidase inhibitor use can lead to hypertensive reactions, including hypertensive crises.
The antihypertensive effects of methyldopa, mecamylamine, reserpine, and veratrum alkaloids may be reduced by sympathomimetics. Beta-adrenergic antagonists may also interact ... | 4 | Stereochemistry |
Regulation of glyceroneogenesis is a therapeutic target of type 2 diabetes treatment, specifically inhibiting it in the liver and increasing it in adipose tissues. Insulin down-regulates glyceroneogenesis in the liver, but it also suppresses it in adipose tissue. To restrict the release of free fatty acids from adipose... | 1 | Biochemistry |
Rotation of the reduction furnace may be a design choice intended to circulate the ore through the furnace. It can also play an active part in the chemical reaction by ensuring mixing between the reactants present. Rotary hearth processes, where the ore rests on a fixed bed and travels through a tunnel, fall into the f... | 8 | Metallurgy |
RNA interference has been used to silence genes associated with several cancers. In in vitro studies of chronic myelogenous leukemia (CML), siRNA was used to cleave the fusion protein, BCR-ABL, which prevents the drug Gleevec (imatinib) from binding to the cancer cells. Cleaving the fusion protein reduced the amount of... | 1 | Biochemistry |
The Hepatitis B viral protein X is believed to cause hepatocellular carcinoma through transformation, typically of liver cells. The viral DNA is incorporated into the host cell's genome causing rapid cell replication and tumor growth. | 1 | Biochemistry |
The production of BCF and similar chlorofluorocarbons has been banned in most countries since January 1, 1994 as part of the Montreal Protocol on ozone depleting substances. Halon 1211 is also a potent greenhouse gas with a 100-year global warming potential 2,070 times that of carbon dioxide and an atmospheric lifetime... | 2 | Environmental Chemistry |
Dimetcote should be applied by specific sprays. Here is a list of several suitable items of equipment typically used by manufacturers. | 8 | Metallurgy |
Ordering is the regularity in which atoms appear in a predictable lattice, as measured from one point. In a highly ordered, perfectly crystalline material, or single crystal, the location of every atom in the structure can be described exactly measuring out from a single origin. Conversely, in a disordered structure su... | 7 | Physical Chemistry |
Compounds with carbon phosphorus(III) multiple bonds are called phosphaalkenes (RC=PR) and phosphaalkynes (RC≡P). They are similar in structure, but not in reactivity, to imines (RC=NR) and nitriles (RC≡N), respectively. In the compound phosphorine, one carbon atom in benzene is replaced by phosphorus. Species of this ... | 0 | Organic Chemistry |
CYC1 is a human gene that is conserved in chimpanzee, Rhesus monkey, dog, cow, mouse, rat, zebrafish, fruit fly, mosquito, C. elegans, S. cerevisiae, K. lactis, E. gossypii, S. pombe, N. crassa, A. thaliana, rice, and frog. There are orthologs of CYC1 in 137 known organisms.
In its structure and function, the cytochrom... | 1 | Biochemistry |
One of the important capabilities of using FTIR photoacoustic spectroscopy has been the ability to evaluate samples in their in situ state by infrared spectroscopy, which can be used to detect and quantify chemical functional groups and thus chemical substances. This is particularly useful for biological samples that c... | 7 | Physical Chemistry |
Heat can be used to trigger the electrocyclization topochemical polymerization. For example, Kana M. Sureshan et al. have developed a series of bio-compatible polymer crystals based on [3+2] Topochemical Azide-Alkyne Cycloaddition (TAAC) reaction and [3+2] topochemical ene-azide cycloaddition (TEAC) reaction. The monom... | 7 | Physical Chemistry |
A chemoreceptor, also known as chemosensor, is a specialized sensory receptor which transduces a chemical substance (endogenous or induced) to generate a biological signal. This signal may be in the form of an action potential, if the chemoreceptor is a neuron, or in the form of a neurotransmitter that can activate a n... | 3 | Analytical Chemistry |
The basis of the reaction is similar to substrate-depletive clock reaction, except for the fact that rate k is very slow leading to the co-existing of substrates and clock species, so there is no need for substrate to be depleted to observe the change in color. The example for this clock is pentathionate/iodate reactio... | 7 | Physical Chemistry |
Most Grignard reactions are conducted in ethereal solvents, especially diethyl ether and THF. Grignard reagents react with 1,4-dioxane to give the diorganomagnesium compounds and insoluble coordination polymer and (R = organic group, X = halide):
This reaction exploits the Schlenk equilibrium, driving it toward the r... | 0 | Organic Chemistry |
Lawesson's reagent is commercially available. It can also be conveniently prepared in the laboratory by heating a mixture of anisole with phosphorus pentasulfide until the mixture is clear and no more hydrogen sulfide is formed, then recrystallized from toluene or xylene.
Samples give a strong odor of hydrogen sulfide ... | 0 | Organic Chemistry |
The dead time is the time for the solutions to go from the mixing point to the observation point, it is the part of the kinetics which cannot be observed. So the lower the dead time, the more information the user can get. In older instruments this could be of the order of 1 ms, but improvements now allow a dead time of... | 7 | Physical Chemistry |
The Bessemer process was the first inexpensive industrial process for the mass production of steel from molten pig iron before the development of the open hearth furnace. The key principle is removal of impurities from the iron by oxidation with air being blown through the molten iron. The oxidation also raises the tem... | 8 | Metallurgy |
One major feature found in protein structures is the addition of sugars (glycosylation) to specific amino acid residues by post translational modification. Complex sugar structures can be connected to these sites, and this can substantially modify the properties of these proteins, a main reason for their presence. At... | 7 | Physical Chemistry |
A spiropyran is a type of organic chemical compound, known for photochromic properties that provide this molecule with the ability of being used in medical and technological areas. Spiropyrans were discovered in the early twentieth century. However, it was in the middle twenties when Fisher and Hirshbergin observed the... | 5 | Photochemistry |
Since liquids often have different boiling points, mixtures or solutions of liquids or gases can typically be separated by distillation, using heat, cold, vacuum, pressure, or other means. Distillation can be found in everything from the production of alcoholic beverages, to oil refineries, to the cryogenic distillatio... | 7 | Physical Chemistry |
The Prix Wilder-Penfield is an award by the government of Quebec that is part of the Prix du Québec, which "goes to scientists whose research aims fall within the field of biomedicine. These fields include the medical sciences, the natural sciences, and engineering". It is named in honour of Wilder Penfield. | 1 | Biochemistry |
See the review of mechanical defenses by Lucas et al., 2000, which remains relevant and well regarded in the subject . Many plants have external structural defenses that discourage herbivory. Structural defenses can be described as morphological or physical traits that give the plant a fitness advantage by deterring he... | 1 | Biochemistry |
In the large intestine, the passage of the digesting food in the colon is a lot slower, taking from 30 to 40 hours until it is removed by defecation. The colon mainly serves as a site for the fermentation of digestible matter by the gut flora. The time taken varies considerably between individuals. The remaining semi-s... | 1 | Biochemistry |
A scintillator ( ) is a material that exhibits scintillation, the property of luminescence, when excited by ionizing radiation. Luminescent materials, when struck by an incoming particle, absorb its energy and scintillate (i.e. re-emit the absorbed energy in the form of light). Sometimes, the excited state is metastab... | 5 | Photochemistry |
Many industrial peroxides are produced using hydrogen peroxide. Reactions with aldehydes and ketones yield a series of compounds depending on conditions. Specific reactions include addition of hydrogen peroxide across the C=O double bond:
In some cases, these hydroperoxides convert to give cyclic diperoxides:
Addition ... | 0 | Organic Chemistry |
The number concentration is defined as the number of entities of a constituent in a mixture divided by the volume of the mixture :
The SI unit is 1/m. | 3 | Analytical Chemistry |
TRFLP is one of several molecular methods aimed to generate a fingerprint of an unknown microbial community. Other similar methods include DGGE, TGGE, ARISA, ARDRA, PLFA, etc.
<br>These relatively high throughput methods were developed in order to reduce the cost and effort in analyzing microbial communities using a cl... | 1 | Biochemistry |
In aqueous solution the concentration of the hydroxide ion is related to the concentration of the hydrogen ion by
The first step in metal ion hydrolysis can be expressed in two different ways
It follows that . Hydrolysis constants are usually reported in the β form and therefore often have values much less than 1. For ... | 7 | Physical Chemistry |
Pentamethylcyclopentadiene gives rise to pentamethylcyclopentadienyl (Cp*) complexes. These ligands are more basic and more lipophilic. Replacing methyl groups with larger substituents results in cyclopentadienes that are so encumbered that pentaalkyl derivatives are no longer possible. Well-studied ligands of this t... | 0 | Organic Chemistry |
Charge-exchange spectroscopy (abbreviated CES or CXS) is a technique commonly used in plasma diagnostics to analyze high-temperature controlled fusion plasmas. In fusion plasmas, the light elements tend to become fully ionized during operation, which makes it challenging to diagnose their properties using conventional ... | 7 | Physical Chemistry |
mTECs as APCs reveal some drawbacks on population level. Their numbers in thymic medulla reach only 100,000 per 2-week-old thymus. Furthermore, average lifespan of mTECs does not exceed 2–3 days, probably due to only known PGE activator Autoimmune regulator (Aire), which requires for its proper function generation of D... | 1 | Biochemistry |
As mentioned above, G-proteins may terminate their own activation due to their intrinsic GTP→GDP hydrolysis capability. However, this reaction proceeds at a slow rate (≈0.02 times/sec) and, thus, it would take around 50 seconds for any single G-protein to deactivate if other factors did not come into play. Indeed, ther... | 1 | Biochemistry |
Beryllides of cobalt and nickel have metallurgical importance as the precipitated phase in beryllium copper alloys. These materials are nonsparking, which allows them to be used in certain hazardous environments.
In nuclear technology, beryllides are investigated as neutron multipliers. Unlike metallic Be, materials s... | 8 | Metallurgy |
One of the largest implementations of Fischer–Tropsch technology is in Bintulu, Malaysia. This Shell facility converts natural gas into low-sulfur Diesel fuels and food-grade wax. The scale is . | 0 | Organic Chemistry |
The earliest evidence for iron-making is a small number of iron fragments with the appropriate amounts of carbon admixture found in the Proto-Hittite layers at Kaman-Kalehöyük and dated to 2200–2000 BCE. Souckova-Siegolová (2001) shows that iron implements were made in Central Anatolia in very limited quantities around... | 8 | Metallurgy |
Sulfuric acid can be used to produce hydrogen from water:
The compounds of sulfur and iodine are recovered and reused, hence the process is called the sulfur–iodine cycle. This process is endothermic and must occur at high temperatures, so energy in the form of heat has to be supplied. The sulfur–iodine cycle has been... | 7 | Physical Chemistry |
The consolidation stage of mucoadhesion involves the establishment of adhesive interactions to reinforce strong or prolonged adhesion. When moisture is present, mucoadhesive materials become activated and the system becomes plasticized. This stimulus allows the mucoadhesive molecules to separate and break free while pr... | 1 | Biochemistry |
While chemical kinetics is concerned with the rate of a chemical reaction, thermodynamics determines the extent to which reactions occur. In a reversible reaction, chemical equilibrium is reached when the rates of the forward and reverse reactions are equal (the principle of dynamic equilibrium) and the concentrations... | 7 | Physical Chemistry |
*Vorobiev E., Lebovka N., (2008). Electrotechnologies for Extraction from Food Plants and Biomaterials, . | 3 | Analytical Chemistry |
Doppler cooling, which is usually accompanied by a magnetic trapping force to give a magneto-optical trap, is by far the most common method of laser cooling. It is used to cool low density gases down to the Doppler cooling limit, which for rubidium-85 is around 150 microkelvins.
In Doppler cooling, initially, the frequ... | 7 | Physical Chemistry |
Low plasticity burnishing (LPB) is a method of metal improvement that provides deep, stable surface compressive residual stresses with little cold work for improved damage tolerance and metal fatigue life extension. Improved fretting fatigue and stress corrosion performance has been documented, even at elevated temper... | 8 | Metallurgy |
Because mechanisms that control the accumulation of damage through the lifetime of a cell are essential to longevity, it is logical that caretaker and gatekeeper genes play a significant role in cellular aging. Increased activity of caretaker genes postpones aging, increasing lifespan. This is because of the regulato... | 1 | Biochemistry |
Electronic entropy is the entropy of a system attributable to electrons' probabilistic occupation of states. This entropy can take a number of forms. The first form can be termed a density of states based entropy. The Fermi–Dirac distribution implies that each eigenstate of a system, , is occupied with a certain probab... | 7 | Physical Chemistry |
In the light-independent (or "dark") reactions, the enzyme RuBisCO captures CO from the atmosphere and, in a process called the Calvin cycle, uses the newly formed NADPH and releases three-carbon sugars, which are later combined to form sucrose and starch. The overall equation for the light-independent reactions in gre... | 5 | Photochemistry |
Disulfides can undergo dynamic exchange reactions with free thiols. The reaction is well documented within the realm of DCvC, and is one of the first reactions demonstrated to have dynamic properties. The application of disulfide chemistry has the added advantage of being a biological motif. Cysteine residues can form ... | 6 | Supramolecular Chemistry |
Methylene is also a common ligand in coordination compounds, such as copper methylene .
Methylene can bond as a terminal ligand, which is called methylidene, or as a bridging ligand, which is called methanediyl. | 0 | Organic Chemistry |
The DNA of one organism is labelled, then mixed with the unlabelled DNA to be compared against. The mixture is incubated to allow DNA strands to dissociate and then cooled to form renewed hybrid double-stranded DNA. Hybridized sequences with a high degree of similarity will bind more firmly, and require more energy to ... | 1 | Biochemistry |
There is a strong scientific consensus that greenhouse effect due to carbon dioxide is a main driver of climate change. Following is an illustrative model meant for a pedagogical purpose, showing the main physical determinants of the effect.
Under this understanding, global warming is determined by a simple energy budg... | 2 | Environmental Chemistry |
The roasting process is generally undertaken in combination with reverberatory furnaces. In the roaster, the copper concentrate is partially oxidised to produce "calcine". Sulfur dioxide is liberated. The stoichiometry of the reaction is:
Roasting generally leaves more sulfur in the calcined product (15% in the case of... | 8 | Metallurgy |
Bacteriorhodopsin (Bop) is a protein used by Archaea, most notably by haloarchaea, a class of the Euryarchaeota. It acts as a proton pump; that is, it captures light energy and uses it to move protons across the membrane out of the cell. The resulting proton gradient is subsequently converted into chemical energy. | 5 | Photochemistry |
Selenols are organic compounds that contain the functional group with the connectivity . Selenols are sometimes also called selenomercaptans and selenothiols. Selenols are one of the principal classes of organoselenium compounds. A well-known selenol is the amino acid selenocysteine. | 0 | Organic Chemistry |
In the field of cell biology, the method of partial cloning (PCL) converts a fully differentiated old somatic cell into a partially reprogrammed young cell that retains all the specialised functions of the differentiated old cell but is simply younger. The method of PCL reverses characteristics associated with old ce... | 1 | Biochemistry |
Iodobenzene dichloride (PhICl) is a complex of iodobenzene with chlorine. As a reagent for organic chemistry, it is used as an oxidant and chlorinating agent. | 0 | Organic Chemistry |
Significant nonspecific protein adsorption during implantation can cause adverse effects. However, some proteins can be beneficial in stabilizing the implant by reducing micro-motion and implant migration, as well as improving the signal quality through increased neuron connection; improving the long-term performance. ... | 7 | Physical Chemistry |
Between 1857 and 1862, Macadam served as honorary secretary of the Philosophical Institute of Victoria, which then became the Royal Society of Victoria in 1860, and was appointed vice-president of it in 1863. He was editor of first five volumes of the societys Transactions. He was active in erecting the Societys Meetin... | 3 | Analytical Chemistry |
Diversity-generating retroelements (DGRs) are a family of retroelements that were first found in Bordetella phage (BPP-1), and since been found in bacteria (e.g.Treponema denticola and Legionella pneumophila), Archaea, Archaean viruses (e.g. ANMV-1), temperate phages (e.g. Hankyphage and CrAss-like phage), and lytic ... | 1 | Biochemistry |
The RBS in prokaryotes is a region upstream of the start codon. This region of the mRNA has the consensus 5-AGGAGG-3, also called the Shine-Dalgarno (SD) sequence. The complementary sequence (CCUCCU), called the anti-Shine-Dalgarno (ASD) is contained in the 3’ end of the 16S region of the smaller (30S) ribosomal subuni... | 1 | Biochemistry |
Epoxides are uncommon in nature. They arise usually via oxygenation of alkenes by the action of cytochrome P450. (but see also the short-lived epoxyeicosatrienoic acids which act as signalling molecules. and similar epoxydocosapentaenoic acids, and epoxyeicosatetraenoic acids.) | 0 | Organic Chemistry |
The vibronic spectra of diatomic molecules in the gas phase also show rotational fine structure. Each line in a vibrational progression will show P- and R-branches. For some electronic transitions there will also be a Q-branch. The transition energies, expressed in wavenumbers, of the lines for a particular vibronic tr... | 7 | Physical Chemistry |
The development of laser heating began only 8 years after Charles Weir, of the National Bureau of Standards (NBS), made the first diamond anvil cell and Alvin Van Valkenburg, NBS, realized the potential of being able to see the sample while under pressure. William Bassett and his colleague Taro Takahashi focused a lase... | 7 | Physical Chemistry |
In elemental analysis by ICP-MS, ICP-AES, GFAA, and Flame AA, dilute nitric acid (0.5–5.0%) is used as a matrix compound for determining metal traces in solutions. Ultrapure trace metal grade acid is required for such determination, because small amounts of metal ions could affect the result of the analysis.
It is also... | 3 | Analytical Chemistry |
There are four ways to crystallize a racemate; three of which H. W. B. Roozeboom had distinguished by 1899:
;Conglomerate (sometimes racemic conglomerate):If the molecules of the substance have a much greater affinity for the same enantiomer than for the opposite one, a mechanical mixture of enantiomerically pure cryst... | 4 | Stereochemistry |
Dye-sensitized solar cells (DSSCs) are made of low-cost materials and do not need elaborate manufacturing equipment, so they can be made in a DIY fashion. In bulk it should be significantly less expensive than older solid-state cell designs. DSSC's can be engineered into flexible sheets and although its conversion effi... | 7 | Physical Chemistry |
Several forms (vitamers) of vitamin D exist. The two major forms are vitamin D or ergocalciferol, and vitamin D or cholecalciferol. Vitamin D without a subscript refers to either D or D, or both, and is known collectively as calciferol.
Vitamin D was chemically characterized in 1931. In 1935, the chemical structure of ... | 1 | Biochemistry |
The properties of RNA make the idea of the RNA world hypothesis conceptually plausible, though its general acceptance as an explanation for the origin of life requires further evidence. RNA is known to form efficient catalysts and its similarity to DNA makes clear its ability to store information. Opinions differ, howe... | 9 | Geochemistry |
In the mechanical stream of thinking about closed systems, heat transferred is defined as a calculated residual amount of energy transferred after the energy transferred as work has been determined, assuming for the calculation the law of conservation of energy, without reference to the concept of temperature. There ar... | 7 | Physical Chemistry |
The catalytic site of NPP consists of a two-metal-ion (bimetallo) Zn catalytic core. These Zn catalytic components are thought to stabilize the transition state of the NPP phosphoryl transfer reaction. | 1 | Biochemistry |
In classic polarography, the standard addition method involves creating two samples – one sample without any spikes, and another one with spikes. By comparing the current measured from two samples, the amount of analyte in the unknown is determined. This approach was the first reported use of standard addition, and was... | 3 | Analytical Chemistry |
Residual topology is a descriptive stereochemical term to classify a number of intertwined and interlocked molecules, which cannot be disentangled in an experiment without breaking of covalent bonds, while the strict rules of mathematical topology allow such a disentanglement. Examples of such molecules are rotaxanes,... | 6 | Supramolecular Chemistry |
Addition of tricyclohexylphosphine to the carbene complex (PPh)(Cl)Ru=C(CHCOMe) results in olefin extrusion and yields an air stable anionic carbido complex. This species displaces a dimethyl sulfide ligand from PdCl(SMe) to give the μ-carbido bimetallic complex (PCy)ClRu≡C-PdCl(SMe). Spark towards a novel type of bond... | 0 | Organic Chemistry |
A uniform structure is identified by each sphere having the same number of contacting neighbours. This gives each sphere an identical neighbourhood. In the example image on the side each sphere has six neighbouring contacts.
The number of contacts is best visualised in the rolled-out contact network. It is created by r... | 3 | Analytical Chemistry |
The conversion of nitrogen gas () into nitrates and nitrites through atmospheric, industrial and biological processes is called nitrogen fixation. Atmospheric nitrogen must be processed, or "fixed", into a usable form to be taken up by plants. Between 5 and 10 billion kg per year are fixed by lightning strikes, but mos... | 1 | Biochemistry |
An outron is a nucleotide sequence at the 5' end of the primary transcript of a gene that is removed by a special form of RNA splicing during maturation of the final RNA product. Whereas intron sequences are located inside the gene, outron sequences lie outside the gene. | 1 | Biochemistry |
The existence of intermolecular forces was first postulated by Johannes Diderik van der Waals in 1873. However, Nobel laureate Hermann Emil Fischer developed supramolecular chemistry's philosophical roots. In 1894, Fischer suggested that enzyme–substrate interactions take the form of a "lock and key", the fundamental p... | 6 | Supramolecular Chemistry |
Organisms inherit their genes from their parents. Asexual organisms simply inherit a complete copy of their parent's genome. Sexual organisms have two copies of each chromosome because they inherit one complete set from each parent. | 1 | Biochemistry |
Although not usually isolated as such, the salt ammonium carbamate is produced on a large scale as an intermediate in the production of the commodity chemical urea from ammonia and carbon dioxide. | 0 | Organic Chemistry |
Perhaps the most direct measurement of s character in a bonding orbital between hydrogen and carbon is via the H−C coupling constants determined from NMR spectra. Theory predicts that J values correlates with s character. In particular, the one bond C-H coupling constant J is related to the fractional s character... | 4 | Stereochemistry |
Column chromatography in chemistry is a chromatography method used to isolate a single chemical compound from a mixture. Chromatography is able to separate substances based on differential adsorption of compounds to the adsorbent; compounds move through the column at different rates, allowing them to be separated into ... | 3 | Analytical Chemistry |
Bumblebees (Bombus spp.), like the honeybee (Apis spp.) collect nectar and pollen from flowers and store them for food. Many individuals must be recruited to forage for food to provide for the hive. Some bee species have highly developed ways of communicating with each other about the location and quality of food resou... | 1 | Biochemistry |
Thermal radiation is characteristically different from conduction and convection in that it does not require a medium and, in fact it reaches maximum efficiency in a vacuum. Thermal radiation is a type of electromagnetic radiation which is often modeled by the propagation of waves. These waves have the standard wave pr... | 7 | Physical Chemistry |
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