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A reversible reaction is a reaction in which the conversion of reactants to products and the conversion of products to reactants occur simultaneously. A and B can react to form C and D or, in the reverse reaction, C and D can react to form A and B. This is distinct from a reversible process in thermodynamics. Weak acid...
7
Physical Chemistry
Sand rammer consists of calibrated sliding weight actuated by cam, a shallow cup to accommodate specimen tube below ram head, a specimen stripper to strip compacted specimen out of specimen tube, a specimen tube to prepare the standard specimen of 50 mm diameter by 50 mm height or 2 inch diameter by 2 inch height for a...
8
Metallurgy
A mixing chamber where a mechanical agitator brings in intimate contact the feed solution and the solvent to carry out the transfer of solute(s). The mechanical agitator is equipped with a motor which drives a mixing and pumping turbine. This turbine draws the two phases from the settlers of the adjacent stages, mixes ...
3
Analytical Chemistry
The main components of an XPS system are the source of X-rays, an ultra-high vacuum (UHV) chamber with mu-metal magnetic shielding, an electron collection lens, an electron energy analyzer, an electron detector system, a sample introduction chamber, sample mounts, a sample stage with the ability to heat or cool the sa...
7
Physical Chemistry
The value is important because it helps determine the Stoichiometry of a system for example in polyurethanes. The value may also be used to calculate equivalent weight and if the functionality is known, the molecular weight also.
3
Analytical Chemistry
A number of microbial metabolisms fractionate sulfur isotopes in distinctive ways, and the sulfur isotopic fingerprints of these metabolisms can be preserved in minerals and ancient organic matter. By measuring the sulfur isotopic composition of these preserved materials, scientists can reconstruct ancient biological p...
9
Geochemistry
Galvanized steel can last for many decades if other supplementary measures are maintained, such as paint coatings and additional sacrificial anodes. Corrosion in non-salty environments is caused mainly by levels of sulfur dioxide in the air.
8
Metallurgy
William Frohring was brought on as part of the team with Gerstenberger and Ruh, and eventually became chief chemist on the project. The group's formula was based on diluted skimmed milk, with lactose and potassium chloride added to reach the human milk level. Among their novel contributions was to use mixtures of fats ...
7
Physical Chemistry
Under the split gene theory, an exon is defined by an ORF. It requires a mechanism to recognize an ORF to have originated. As an ORF is defined by a contiguous coding sequence bounded by stop codons, these stop codon ends had to be recognized by the exon-intron gene recognition system. This system could have defined th...
1
Biochemistry
Ionic selectivity is defined to evaluate the performance of a nano-channel for ionic flow control. Ionic selectivity is the ratio of the difference in currents of majority and minority carriers to the total current carried by both positive and negative ions, . For a nanochannel with perfect control over cation and anio...
7
Physical Chemistry
In chemical thermodynamics, activity (symbol ) is a measure of the "effective concentration" of a species in a mixture, in the sense that the species' chemical potential depends on the activity of a real solution in the same way that it would depend on concentration for an ideal solution. The term "activity" in this s...
7
Physical Chemistry
Acid catalysis is mainly used for organic chemical reactions. Many acids can function as sources for the protons. Acid used for acid catalysis include hydrofluoric acid (in the alkylation process), phosphoric acid, toluenesulfonic acid, polystyrene sulfonate, heteropoly acids, zeolites. Strong acids catalyze the hydrol...
7
Physical Chemistry
When a compound has limited solubility in water it is common practice (in the pharmaceutical industry, for example) to determine pK values in a solvent mixture such as water/dioxane or water/methanol, in which the compound is more soluble. In the example shown at the right, the pK value rises steeply with increasing pe...
7
Physical Chemistry
Jeremy Munday writes that although "unexpected effects will likely occur" with global PDRC implementation, that "these structures can be removed immediately if needed, unlike methods that involve dispersing particulate matter into the atmosphere, which can last for decades." Wang et al. state that stratospheric aerosol...
7
Physical Chemistry
Of the various methods of labeling biomolecules, fluorescent labels are advantageous in that they are highly sensitive even at low concentration and non-destructive to the target molecule folding and function. Green fluorescent protein is a naturally occurring fluorescent protein from the jellyfish Aequorea victoria th...
1
Biochemistry
The Liebermann reagent named after Hungarian chemist Leo Liebermann (1852-1926) is used as a simple spot-test to presumptively identify alkaloids as well as other compounds. It is composed of a mixture of potassium nitrite and concentrated sulfuric acid. 1 g of potassium nitrite is used for every 10 mL of sulfuric acid...
3
Analytical Chemistry
In jaundice owing to hemolysis (prehepatic, or hemolytic, jaundice), the pathophysiology is that overproduction of bilirubin from the extravascular or intravascular hemolysis overwhelms the capacity of the liver to excrete it. The bilirubin present in the plasma is largely unconjugated in this setting as they haven't b...
1
Biochemistry
Bioleaching is in general simpler and, therefore, cheaper to operate and maintain than traditional processes, since fewer specialists are needed to operate complex chemical plants. And low concentrations are not a problem for bacteria because they simply ignore the waste that surrounds the metals, attaining extraction ...
8
Metallurgy
2-O-methylation refers to the methylation of the 2 hydroxyl group of the ribose within an RNA nucleotide. 2'-O-methylation is found in the five-prime cap of mRNAs in higher eukaryotes. It is involved in differentiating between self and non-self mRNA. Without the 2′-O-methylation mark the immune system triggers higher l...
1
Biochemistry
A-values help predict the conformation of cyclohexane rings. The most stable conformation will be the one which has the substituent or substituents equatorial. When multiple substituents are taken into consideration, the conformation where the substituent with the largest A-value is equatorial is favored. The utility...
4
Stereochemistry
A nearly universal rule in copyediting of articles for medical journals and other health science publications is that abbreviations and acronyms must be expanded at first use, to provide a glossing type of explanation. Typically no exceptions are permitted except for small lists of especially well known terms (such as ...
1
Biochemistry
The emission of electromagnetic radiation (EMR) during plastic deformation and crack propagation in metals and rocks has been studied. The EMR emissions from metals and alloys have also been explored and confirmed. Molotskii presented a dislocation mechanism for this type of EMR emission. In 2005, Srilakshmi and Misra ...
5
Photochemistry
Oxanorbornadiene (or another activated alkene) reacts with azides, giving triazoles as a product. However, these product triazoles are not aromatic as they are in the CuAAC or SPAAC reactions, and as a result are not as stable. The activated double bond in oxanobornadiene makes a triazoline intermediate that subsequent...
0
Organic Chemistry
One of the challenges in studying abiogenesis is that the system of reproduction and metabolism utilized by all extant life involves three distinct types of interdependent macromolecules (DNA, RNA, and proteins). This suggests that life could not have arisen in its current form, which has led researchers to hypothesize...
9
Geochemistry
RNA activation (RNAa) is a small RNA-guided and Argonaute (Ago)-dependent gene regulation phenomenon in which promoter-targeted short double-stranded RNAs (dsRNAs) induce target gene expression at the transcriptional/epigenetic level. RNAa was first reported in a 2006 PNAS paper by Li et al. who also coined the term "R...
1
Biochemistry
The reverse anomeric effect, proposed in 1965 by R. U. Lemieux, is the tendency for electropositive groups at the anomeric position to be oriented equatorially. Original publication reported this phenomenon with N-(2,3,4,6-tetra-O-acetyl-α--glucopyranosyl)-4-methylpyridinium bromide. However, further studies have shown...
0
Organic Chemistry
In contrast to benzene ring, pyridine efficiently supports several nucleophilic substitutions. The reason for this is relatively lower electron density of the carbon atoms of the ring. These reactions include substitutions with elimination of a hydride ion and elimination-additions with formation of an intermediate ary...
0
Organic Chemistry
The pzc is typically obtained by acid-base titrations of colloidal dispersions while monitoring the electrophoretic mobility of the particles and the pH of the suspension. Several titrations are required to distinguish pzc from iep, using different electrolytes (including varying the electrolyte ionic strength). Once s...
7
Physical Chemistry
For ionic compounds, the standard enthalpy of formation is equivalent to the sum of several terms included in the Born–Haber cycle. For example, the formation of lithium fluoride, may be considered as the sum of several steps, each with its own enthalpy (or energy, approximately): # , the standard enthalpy of atomizat...
7
Physical Chemistry
Supercritical water oxidation (SCWO) is a process that occurs in water at temperatures and pressures above a mixture's thermodynamic critical point. Under these conditions water becomes a fluid with unique properties that can be used to advantage in the destruction of recalcitrant and hazardous wastes such as polychlor...
7
Physical Chemistry
In ISCR, many reductive processes can take place. There are hydrogenolysis, β-elimination, hydrogenation, α-elimination, and electron transfer. The specific combination of reductive processes that actually take place in the subsurface depends on the species of contaminant that is present and also the type of reduction ...
2
Environmental Chemistry
If MRL of some medicinal plant is not known it is calculated by the formula: where SF is the safety factor *MDI is the mean daily intake *W is the body weight *ADI is the acceptable daily intake
2
Environmental Chemistry
Medications can adjust the release of brain neurotransmitters in cases of depression, anxiety disorder, schizophrenia and other mental disorders because an imbalance within neurotransmitter systems can emerge as consistent characteristics in behaviour compromising people's lives. All people have a weaker form of such i...
1
Biochemistry
N-substituted derivatives are somewhat stable. They are invoked but rarely observed as intermediates in the Mannich reaction. These N,N,N-trisubstituted hexahydro-1,3,5-triazines arise from the condensation of the amine and formaldehyde as illustrated by the route to 1,3,5-trimethyl-1,3,5-triazacyclohexane: Although ad...
0
Organic Chemistry
Respiration occurs by both plants and animals throughout the water column, resulting in the destruction, or usage, of organic matter, but photosynthesis can only take place via photosynthetic algae in the presence of light, nutrients and CO. In well-mixed water columns plankton are evenly distributed, but a net product...
5
Photochemistry
Bis(chloromethyl) ether is an organic compound with the chemical formula (ClCH)O. It is a colourless liquid with an unpleasant suffocating odour and it is one of the chloroalkyl ethers. Bis(chloromethyl) ether was once produced on a large scale, but was found to be highly carcinogenic and thus such production has cease...
0
Organic Chemistry
When covalently attached to a surface, PPGs do not exhibit any surface-induced properties (i.e. they behave like PPGs in solution, and do not exhibit any new properties because of their proximity to a surface). Consequently, PPGs can be patterned on a surface and removed in manner analogous to lithography to create a m...
5
Photochemistry
Time-domain diffuse optical sources must have the following characteristics; emission wavelength in the optical window i.e. between 650 and 1350 nanometre (nm); a narrow full width at half maximum (FWHM), ideally a delta function; high repetition rate (>20 MHz) and finally, sufficient laser power (>1 mW) to achieve go...
7
Physical Chemistry
Aside from its immense environmental impacts, R114, like most chlorofluoroalkanes, forms phosgene gas when exposed to a naked flame.
2
Environmental Chemistry
The Laporte rule is a selection rule formally stated as follows: In a centrosymmetric environment, transitions between like atomic orbitals such as s-s, p-p, d-d, or f-f, transitions are forbidden. The Laporte rule (law) applies to electric dipole transitions, so the operator has u symmetry (meaning ungerade, odd). p o...
7
Physical Chemistry
Pyruvate produced by glycolysis is converted to lactate. This reaction is catalysed by the enzyme lactate dehydrogenase (LDHA). pyruvate + NADH + H → lactate + NAD
1
Biochemistry
Trimethylsilyl azide , and tributyltin azide , have all been used, including enantioselective modifications of the reaction are also known. Aminoazides are accessible by the epoxide and aziridine ring cleavage, respectively.
0
Organic Chemistry
For any point in a unit cell, given by fractional coordinates, one can apply a symmetry operation to the point. In some cases it will move to new coordinates, while in other cases the point will remain unaffected. For example, reflecting across a mirror plane will switch all the points left and right of the mirror plan...
3
Analytical Chemistry
David Phillips, (born 3 December 1939) is a British chemist specialising in photochemistry and lasers, and was president of the Royal Society of Chemistry from 2010 to 2012.
5
Photochemistry
Level -1 fragments are used to help cloning large level 0 modules. To clone level -1 fragments, blunt-end cloning with restriction ligation can be used. The vector used in cloning level -1 fragments cannot contain Type IIS restriction site BpiI that is used for the following assembly step. Moreover, the vector should a...
1
Biochemistry
Capnellene is a naturally occurring tricyclic hydrocarbon derived from Capnella imbricata, a species of soft coral found in Indonesia. Since the 1970s, capnellene has been targeted for synthesis by numerous investigators due to its stereochemistry, functionality, and the interesting geometry of the carbon skeleton. Man...
0
Organic Chemistry
A recent example of the Fürst-Plattner rule can be seen from Chrisman et al. where limonene is epoxidized to give a 1:1 mixture of diastereomers. Exposure to a nitrogen nucleophile in water at reflux provides only one ring opened product in 75-85% ee.
4
Stereochemistry
Adhesive forces between a liquid and solid cause a liquid drop to spread across the surface. Cohesive forces within the liquid cause the drop to ball up and avoid contact with the surface. The contact angle (θ), as seen in Figure 1, is the angle at which the liquid–vapor interface meets the solid–liquid interface. The ...
7
Physical Chemistry
Photosensitization is a process of transferring the energy of absorbed light. After absorption, the energy is transferred to the (chosen) reactants. This is part of the work of photochemistry in general. In particular this process is commonly employed where reactions require light sources of certain wavelengths that ar...
7
Physical Chemistry
Nucleophilic substitution reactions occur when a nucleophilic molecule attacks a positive or partially positive electrophilic center by breaking and creating a new bond. S1 and S2 are two different mechanisms for nucleophilic substitution, and S1 involves a carbocation intermediate. In S1, a leaving group is broken off...
7
Physical Chemistry
Methods for the stereoselective synthesis of cyclopropanes from diazocarbonyl compounds and olefins have relied on either the use of pre-formed chiral rhodium catalysts or chiral auxiliaries on the diazocarbonyl compound. For example, Rh[S-DOSP] is a highly effective catalyst for the enantioselective cyclopropanation o...
0
Organic Chemistry
A simple cubic unit cell, with stacks of atoms arranged as if at the eight corners of a cube would form a single cubic hole or void in the center. If these voids are occupied by ions of opposite charge from the parent lattice, the cesium chloride structure is formed.
3
Analytical Chemistry
Titanium dioxide takes part in self-cleaning glass. Free radicals generated from oxidize organic matter. The rough wedge-like surface can be modified with a hydrophobic monolayer of octadecylphosphonic acid (ODP). surfaces that were plasma etched for 10 seconds and subsequent surface modifications with ODP showed a ...
5
Photochemistry
In order for euxinic conditions to persist, a positive feedback loop must perpetuate organic matter export to bottom waters and reduction of sulfate under anoxic conditions. Organic matter export is driven by high levels of primary production in the photic zone, supported by a continual supply of nutrients to the oxic ...
9
Geochemistry
Nitric acid is normally considered to be a strong acid at ambient temperatures. There is some disagreement over the value of the acid dissociation constant, though the pK value is usually reported as less than −1. This means that the nitric acid in diluted solution is fully dissociated except in extremely acidic soluti...
3
Analytical Chemistry
More organic matter is preserved in sediments if there is high primary production, or the sediment is fine-grained. The lack of oxygen helps preservation greatly, and that also is caused by a large supply of organic matter. Soil does not usually preserve organic matter, it would need to be acidified or water logged, as...
9
Geochemistry
Typical anions in ionic liquids include the following: tetrafluoroborate (BF), hexafluorophosphate (PF), bis-trifluoromethanesulfonimide (NTf), trifluoromethanesulfonate (OTf), dicyanamide (N(CN)), hydrogen sulphate (HSO), and ethyl sulphate (EtOSO). Magnetic ionic liquids can be synthesized by incorporating paramagnet...
7
Physical Chemistry
Copepods are known to be the primary consumers of diatoms in the water column and initiate the production of PUA upon grazing. The consumption of PUA-producing diatoms by copepods has been shown to diminish their reproductive success. Specifically, female copepods that consume diatoms spawn eggs with low viabilities a...
1
Biochemistry
Alcohols add to electrophilically activated alkenes. The method is atom-economical: : RC=CR + R–OH → RCH–C(–O–R)–R Acid catalysis is required for this reaction. Commericially important ethers prepared in this way are derived from isobutene or isoamylene, which protonate to give relatively stable carbocations. Using e...
0
Organic Chemistry
The Newbery-Vautin chlorination process is a method for extracting gold from its ore through the use of chlorination. This process was jointly developed by James Cosmo Newbery and Claude Vautin.
8
Metallurgy
A RHEED system requires an electron source (gun), photoluminescent detector screen and a sample with a clean surface, although modern RHEED systems have additional parts to optimize the technique. The electron gun generates a beam of electrons which strike the sample at a very small angle relative to the sample surface...
3
Analytical Chemistry
In 1999, the virulence genes associated with Mycobacterium tuberculosis were identified through transposon mutagenesis-mediated gene knockout. A plasmid named pCG113 containing kanamycin resistance genes and the IS1096 insertion sequence was engineered to contain variable 80-base pair tags. The plasmids were then trans...
1
Biochemistry
Water-splitting photoelectrochemical (PEC) cells use light energy to decompose water into hydrogen and oxygen within a two-electrode cell. In theory, three arrangements of photo-electrodes in the assembly of PECs exist: * photo-anode made of a n-type semiconductor and a metal cathode * photo-anode made of a n-type semi...
5
Photochemistry
Under normal circumstances, the spent chromophore is discharged from the protein by an incoming "recharged" chromophore. However, sometimes the spent chromophore may leave the opsin protein prior to its replacement, when it is bound to the ABCA4 protein (also known as ABCR). At this stage, it is also transformed to all...
1
Biochemistry
It is believed that both DXS and DXR are rate-determining enzymes, allowing them to regulate carotenoid levels. This was discovered in an experiment where DXS and DXR were genetically overexpressed, leading to increased carotenoid expression in the resulting seedlings. Also, J-protein (J20) and heat shock protein 70 (H...
5
Photochemistry
The ocean can be conceptually divided into a surface layer within which water makes frequent (daily to annual) contact with the atmosphere, and a deep layer below the typical mixed layer depth of a few hundred meters or less, within which the time between consecutive contacts may be centuries. The dissolved inorganic c...
5
Photochemistry
Alkyl groups form homologous series. The simplest series have the general formula . Alkyls include methyl, (), ethyl (), propyl (), butyl (), pentyl (), and so on. Alkyl groups that contain one ring have the formula , e.g. cyclopropyl and cyclohexyl. The formula of alkyl radicals are the same as alkyl groups, except th...
0
Organic Chemistry
inflammation induced by cholesterol loading into immune cells causes heart disease. A class of drugs called statins blocks cholesterol synthesis and is used extensively in treating heart disease.
1
Biochemistry
It is legal under EU law to sell and buy seeds from a composite cross population as an experiment in the period between 2014 and 2018.
1
Biochemistry
A variety of natural and synthetic inhibitors of ATP synthase have been discovered. These have been used to probe the structure and mechanism of ATP synthase. Some may be of therapeutic use. There are several classes of ATP synthase inhibitors, including peptide inhibitors, polyphenolic phytochemicals, polyketides, org...
5
Photochemistry
In an ecological context, phototrophs are often the food source for neighboring heterotrophic life. In terrestrial environments, plants are the predominant variety, while aquatic environments include a range of phototrophic organisms such as algae (e.g., kelp), other protists (such as euglena), phytoplankton, and bacte...
5
Photochemistry
In chemistry, trigonal planar is a molecular geometry model with one atom at the center and three atoms at the corners of an equilateral triangle, called peripheral atoms, all in one plane. In an ideal trigonal planar species, all three ligands are identical and all bond angles are 120°. Such species belong to the poin...
4
Stereochemistry
Hydroboration is typically anti-Markovnikov, i.e. the hydrogen adds to the most substituted carbon of the double bond. That the regiochemistry is reverse of a typical HX addition reflects the polarity of the B-H bonds. Hydroboration proceeds via a four-membered transition state: the hydrogen and the boron atoms added ...
0
Organic Chemistry
Sometimes modulation of transgene expression may be necessary since strong constitutive expression of a therapeutic gene in retinal tissues could be deleterious for long-term retinal function. Different methods have been utilized for the expression modulation. One way is using exogenously regulatable promoter system i...
1
Biochemistry
To a solution of 1,3-dihydro-1,3-bis(chloromethyl)benzo[c] thiophene 2,2-dioxide (0.584 g, 2.2 mmol) in 50 ml of dry benzene was added 0.80 mL (2.8 mmol) of a 70% benzene solution of NaAlH(OCHCHOCH) via syringe, and the solution was refluxed for 12 hours. The mixture was cooled to 0° and decomposed with 20% sulfuric ac...
0
Organic Chemistry
How stereoselectivity is achieved in asymmetric nucleophilic epoxidations depends on the method employed. Covered here are various methods for the asymmetric nucleophilic epoxidation of electron-poor olefins. See below for a survey of the substrate scope of the reaction. When chiral, non-racemic peroxides are used, the...
0
Organic Chemistry
* Encyclopædia Britannica, 14th ed. * J. Day & R. F. Tylecote (eds.), The Industrial Revolution in Metals (1991) * P. W. King, "The Cupola at Bristol", Somerset Araeology and Natural History 140 (for 1997), 37–52 * P. W. King, "Sir Clement Clerke and the Adoption of coal in metallurgy", Transactions of the Newcomen Soc...
8
Metallurgy
Deformation twinning is a response to shear stress. The crystal structure is displaced along successive planes of the crystal, a process also called glide. The twinning is always reflection twinning and the glide plane is also the mirror plane. Deformation twinning can be observed in a calcite cleavage fragment by appl...
3
Analytical Chemistry
While mouse and human antibodies are structurally similar, the differences between them were sufficient to invoke an immune response when murine monoclonal antibodies were injected into humans, resulting in their rapid removal from the blood, as well as systemic inflammatory effects and the production of human anti-mou...
1
Biochemistry
The decay energy, Q (also called the Q-value of the reaction), corresponds to a disappearance of mass. For the alpha decay nuclear reaction: , (where P is the parent nuclide and D the daughter). , or to put in the more commonly used units: Q (MeV) = -931.5 ΔM (Da), (where ΔM = ΣM - ΣM). When the daughter nuclide and...
7
Physical Chemistry
A property of a physical system, such as the entropy of a gas, that stays approximately constant when changes occur slowly is called an adiabatic invariant. By this it is meant that if a system is varied between two end points, as the time for the variation between the end points is increased to infinity, the variation...
7
Physical Chemistry
The terms glycans and polysaccharides are defined by IUPAC as synonyms meaning "compounds consisting of a large number of monosaccharides linked glycosidically". However, in practice the term glycan may also be used to refer to the carbohydrate portion of a glycoconjugate, such as a glycoprotein, glycolipid, or a prote...
0
Organic Chemistry
Cultural or anthropogenic eutrophication is the process that causes eutrophication because of human activity. The problem became more apparent following the introduction of chemical fertilizers in agriculture (green revolution of the mid-1900s). Phosphorus and nitrogen are the two main nutrients that cause cultural eut...
2
Environmental Chemistry
Ammonium carbamate solutions are highly corrosive to metallic construction materials – even to resistant forms of stainless steel – especially in the hottest parts of the synthesis plant such as the stripper. Historically corrosion has been minimized (although not eliminated) by continuous injection of a small amount o...
0
Organic Chemistry
Alkali metals also dissolve in some small primary amines, such as methylamine and ethylamine and hexamethylphosphoramide, forming blue solutions. THF dissolves alkali metal, but a Birch reduction (see ) analogue does not proceed without a diamine ligand. Solvated electron solutions of the alkaline earth metals magnesi...
0
Organic Chemistry
Certain titanium and zirconium complexes catalyze intermolecular hydroamination of alkynes and allenes. Both stoichiometric and catalytic variants were initially examined with zirconocene bis(amido) complexes. Titanocene amido and sulfonamido complexes catalyze the intra-molecular hydroamination of aminoalkenes via a [...
0
Organic Chemistry
To perform microcrystallization, a small piece of lichen is extracted using acetone or other solvents, filtered, and evaporated to yield a residue. The residue is transferred to a microscope slide, and a drop of microcrystallization reagent is added before capping with a cover glass. Commonly used reagents include GAW ...
3
Analytical Chemistry
Torovirus is a genus of viruses within the family Coronaviridae, subfamily Torovirinae that primarily infect vertebrates and include Berne virus of horses and Breda virus of cattle. They cause gastroenteritis in mammals, including humans but rarely.
1
Biochemistry
Stereochemical control within [4+4] reactions is not common, however it does exist. Enol-exo stereoselectivity is possible using certain cross-linking techniques and has been met with moderate success. Control over the configuration at newly established bridgehead centers by use of preexisting stereocenters has been la...
5
Photochemistry
As in the standard code, initiation is most efficient at AUG. In addition, GUG and UUG starts are documented in archaea and bacteria. In Escherichia coli, UUG is estimated to serve as initiator for about 3% of the bacteriums proteins. CUG is known to function as an initiator for one plasmid-encoded protein (RepA) in...
1
Biochemistry
* In the 2016 film Spectral, the US military battles mysterious enemy creatures fashioned out of Bose–Einstein condensates. * In the 2003 novel Blind Lake, scientists observe sentient life on a planet 51 light-years away using telescopes powered by Bose–Einstein condensate-based quantum computers. * The video game fran...
7
Physical Chemistry
Making a distinction between homogeneous and heterogeneous mixtures is a matter of the scale of sampling. On a coarse enough scale, any mixture can be said to be homogeneous, if the entire article is allowed to count as a "sample" of it. On a fine enough scale, any mixture can be said to be heterogeneous, because a sam...
7
Physical Chemistry
The carbon-silicon bond is highly electron-releasing and can stabilize a positive charge in the β position through hyperconjugation. Electrophilic additions to allyl- and vinylsilanes take advantage of this, and site selectivity generally reflects this property—electrophiles become bound to the carbon γ to the silyl gr...
0
Organic Chemistry
Levobupivacaine, the S(-)-enantiomer of bupivacaine has been developed as an alternative to the racemic mixture, as it has been shown to have a lower cardiotoxicity than bupivacaine. Under European Union advice, it can be applied for minor and major surgical anaesthesia, as well as (post-operative) pain management. Par...
4
Stereochemistry
A number of industrial processes produce combustible dust as a by-product. The most common being wood dust. Combustible dust has been defined as: a solid material composed of distinct particles or pieces, regardless of size, shape, or chemical composition, which presents a fire or deflagration hazard when suspended in ...
7
Physical Chemistry
Pulse labelling is a biochemistry technique of identifying the presence of a target molecule by labeling a sample with a radioactive compound. This is mainly done to identify the stage at which the messenger RNA is being produced in a cell.
1
Biochemistry
Isomerism was first observed in 1827, when Friedrich Wöhler prepared silver cyanate and discovered that, although its elemental composition of was identical to silver fulminate (prepared by Justus von Liebig the previous year), its properties were distinct. This finding challenged the prevailing chemical understanding...
4
Stereochemistry
RNA polymerase II holoenzyme is a form of eukaryotic RNA polymerase II that is recruited to the promoters of protein-coding genes in living cells. It consists of RNA polymerase II, a subset of general transcription factors, and regulatory proteins known as SRB proteins. Part of the assembly of the holoenzyme is referre...
1
Biochemistry
Similar to the draw spinning technique the direct ink writing technique utilized reversible physical solidification to produce hydrogel fibers. The pregel solution was liqufied through shear thinning process which can be generated by adding microscopic particles such as mircrogel. After leaving the nuzzle, the hydrogel...
7
Physical Chemistry
An alteration in copy number state with respect to a single-copy reference locus is referred to as a “copy number variation” (CNV) if it appears in germline cells, or a copy number alteration (CNA) if it appears in somatic cells. A CNV or CNA could be due to a deletion or amplification of a locus with respect to the nu...
1
Biochemistry