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Bacterial transcription is the process in which a segment of bacterial DNA is copied into a newly synthesized strand of messenger RNA (mRNA) with use of the enzyme RNA polymerase.
The process occurs in three main steps: initiation, elongation, and termination; and the end result is a strand of mRNA that is complementar... | 1 | Biochemistry |
Particles of refractory material in contact with aluminium can detach and become inclusions. We can find graphite inclusions (C), alumina inclusions (alpha-AlO), CaO, SiO, …
After some time, graphite refractory in contact with aluminium will react to create aluminum carbides (harder and more detrimental inclusions).
In... | 8 | Metallurgy |
In general, polymeric mixtures are far less miscible than mixtures of small molecule materials. This effect results from the fact that the driving force for mixing is usually entropy, not interaction energy. In other words, miscible materials usually form a solution not because their interaction with each other is more... | 7 | Physical Chemistry |
During the initial phases of glycolysis and the TCA cycle, cofactors such as NAD+ donate and accept electrons that aid in the electron transport chain's ability to produce a proton gradient across the inner mitochondrial membrane. The ATP synthase complex exists within the mitochondrial membrane (F portion) and protrud... | 1 | Biochemistry |
Along with the related organotantalum species, niobium alkylidenes were among the first Scrock carbenes studied. The first syntheses of these complexes involved addition of organolithium reagents lacking β-hydrogens into hindered Nb(V) complexes followed by α-proton elimination. As compared to tantalum alkylidenes, nio... | 0 | Organic Chemistry |
The Shibasaki synthesis ((-) chiral, 2002) was a second published method in strychnine total synthesis using an asymmetric reaction step. Cyclohexenone 1 was reacted with dimethyl malonate 2 in an asymmetric Michael reaction using AlLibis(binaphthoxide) to form chiral diester 3. Its ketone group was protected as an ace... | 0 | Organic Chemistry |
Ampicillin overdose can cause behavioral changes, confusion, blackouts, and convulsions, as well as neuromuscular hypersensitivity, electrolyte imbalance, and kidney failure. | 4 | Stereochemistry |
Nanocrystalline materials can be prepared in several ways. Methods are typically categorized based on the phase of matter the material transitions through before forming the nanocrystalline final product. | 8 | Metallurgy |
EosFP emits a strong green fluorescence (516 nm) that changes irreversibly to red (581 nm) when irradiated with UV-light of 390 nm. This modification occurs due to a break in the peptide backbone next to the chromophore. This mechanism allows for localized tagging of the protein and makes EosFP an appropriate tool for ... | 1 | Biochemistry |
In order to survive, plants must be able to respond to many biotic and abiotic stresses, including pathogen attack, piercing/sucking insects, herbivory, and mechanical wounding. These stresses activate specialized signal transduction pathways, which are specific to the stressor and the amount of tissue damage inflicted... | 1 | Biochemistry |
Irrespective of scan rate, the area under the peak (in units of AV) is equal to , where is the number of electrons exchanged in the oxidation/reduction of the center, is the electrode surface and is the electroactive coverage (in units of mol/cm). The latter can therefore be deduced from the area under the peak afte... | 7 | Physical Chemistry |
Emissive power is the rate at which radiation is emitted per unit area. It is a measure of heat flux. The total emissive power from a surface is denoted as and can be determined by,where is in units of steradians and is the total intensity.
The total emissive power can also be found by integrating the spectral emiss... | 7 | Physical Chemistry |
Directional freezing freezes from only one direction.
Directional freezing can freeze water, from only one direction or side of a container, into clear ice.
Directional freezing in a domestic freezer can be done by putting water in a insulated container so that the water freezes from the top down, and removing before f... | 6 | Supramolecular Chemistry |
Kujawinski joined the faculty at Barnard College in 2002, and held an adjunct position at Columbia University. She spent two years at Barnard College before being awarded a National Science Foundation CAREER Award and returning to the Woods Hole Oceanographic Institution.
In an effort to understand how cellular metabol... | 9 | Geochemistry |
Fluorescent moieties emit photons several nanoseconds after absorption following an exponential decay curve, which differs between dyes and depends on the surrounding solvent. When the dye is attached to a macromolecules the decay curve becomes multiexponential. Conjugated dyes generally have a lifetime between 1–10 ns... | 1 | Biochemistry |
A wetting transition (Cassie–Wenzel transition) may occur during the process of wetting of a solid (or liquid) surface with a liquid. The transition corresponds to a certain change in contact angle, the macroscopic parameter characterizing wetting. Various contact angles can co-exist on the same solid substrate. Wettin... | 7 | Physical Chemistry |
The ARC gene, located on chromosome 15 in the mouse, chromosome 7 in the rat, and chromosome 8 in the human, is conserved across vertebrate species and has low sequence homology to spectrin, a cytoskeletal protein involved in forming the actin cellular cortex. A number of promoter and enhancer regions have been identif... | 1 | Biochemistry |
Although usually the anion of the mineralizer is most active in dissolving the nutrient material, the cation also exerts an influence in some cases. The mineralizer can interact with impurities on the surface of the crystal and increase the growth rate. For example, the growth rate for sapphire (AlO) and zincite (ZnO) ... | 7 | Physical Chemistry |
Many applications have been considered, but few have been commercialized. ILs are used in the production of gasoline by catalyzing alkylation.
An IL based on tetraalkylphosphonium iodide is a solvent for tributyltin iodide, which functions as a catalyst to rearrange the monoepoxide of butadiene. This process was commer... | 7 | Physical Chemistry |
The Kuwajima Taxol total synthesis by the group of Isao Kuwajima of the Tokyo Institute of Technology is one of several efforts in taxol total synthesis published in the 1990s. The total synthesis of Taxol is considered a landmark in organic synthesis.
This synthesis is truly synthetic without any help from small biomo... | 0 | Organic Chemistry |
Paints, inks, and dyes that are organic are more susceptible to photodegradation than those that are not. Ceramics are almost universally colored with non-organic origin materials so as to allow the material to resist photodegradation even under the most relentless conditions, maintaining its color. | 5 | Photochemistry |
The suffix -ene is used in organic chemistry to form names of organic compounds where the -C=C- group has been attributed the highest priority according to the rules of organic nomenclature. Sometimes a number between hyphens is inserted before it to say that the double bond is between that atom and the atom with the n... | 0 | Organic Chemistry |
Tissue samples are lysed in buffer supplemented with leupeptin to maintain enzymatic activity. The samples are standardized for protein concentration and then loaded into a polyacrylamide gel for SDS-PAGE. After separation of proteins by molecular weight is complete, the gel is incubated in a renaturing buffer to resto... | 1 | Biochemistry |
As a meal containing carbohydrates or protein is eaten and digested, blood glucose levels rise, and the pancreas secretes insulin. Blood glucose from the portal vein enters liver cells (hepatocytes). Insulin acts on the hepatocytes to stimulate the action of several enzymes, including glycogen synthase. Glucose molecul... | 1 | Biochemistry |
In June 2020, the Cold Atom Laboratory experiment on board the International Space Station successfully created a BEC of rubidium atoms and observed them for over a second in free-fall. Although initially just a proof of function, early results showed that, in the microgravity environment of the ISS, about half of the ... | 7 | Physical Chemistry |
The steric isotope effect is a SKIE that does not involve bond breaking or formation. This effect is attributed to the different vibrational amplitudes of isotopologues. An example of such an effect is the racemization of 9,10-dihydro-4,5-dimethylphenanthrene. The smaller amplitude of vibration for deuterium as compare... | 7 | Physical Chemistry |
In X-ray crystallography, a difference density map or Fo–Fc map shows the spatial distribution of the difference between the measured electron density of the crystal and the electron density explained by the current model.
A way to compute this map has been formulated for cyro-EM. | 3 | Analytical Chemistry |
The microbubbles used today are composed of a gas core and a surrounding shell. The makeup of these elements may vary depending on the preferred physical and chemical properties. Microbubble shells have been formed with lipids, galactose, albumin, or polymers. The gas core can be made up of air or heavy gases like nit... | 1 | Biochemistry |
TosMIC (toluenesulfonylmethyl isocyanide) is an organic compound with the formula CHCHSOCHNC. The molecule contains both sulfonyl and isocyanide groups. It is a colourless solid that, unlike many isocyanides, is odorless. It is prepared by dehydration of the related formamide derivative. It is used in the Van Leusen re... | 0 | Organic Chemistry |
This is the hybrid of both of the above techniques. The upper part of ascending chromatography can be folded over a rod in order to allow the paper to become descending after crossing the rod. | 3 | Analytical Chemistry |
A sculpture titled Bamboozle, by Jacobus Verhoeff and his son Tom Verhoeff, is in the form of a fragment of the Laves graph, with its vertices represented by multicolored interlocking acrylic triangles. It was installed in 2013 at the Eindhoven University of Technology. | 3 | Analytical Chemistry |
In a common application, potassium thioacetate is combined with alkylating agents to give thioacetate esters (X = halide):
Hydrolysis of these esters affords thiols:
The thioacetate esters can also be cleaved with methanethiol in the presence of stoichiometric base, as illustrated in the preparation of pent-4-yne-1-thi... | 0 | Organic Chemistry |
Negishi was born in Xinjing (today known as Changchun), the capital of Manchukuo, in July 1935. Following the transfer of his father who worked at the South Manchuria Railway in 1936, he moved to Harbin, and lived eight years there. In 1943, when he was nine, the Negishi family moved to Incheon, and a year later to Kyo... | 0 | Organic Chemistry |
In 1977, Edmonds et al. reported the identification, isolation, and synthesis of major arsenic-containing substance in sea organisms, the arsenobetaine. In 1999, NRC certified arsenobetaine in the dogfish muscle material DORM-2, which became the first matrix reference material certified for arsenobetaine. Before DORM-2... | 1 | Biochemistry |
The clones that bind to a particular epitope with greater strength are more likely to be selected for further proliferation in the germinal centers of the follicles in various lymphoid tissues like the lymph nodes. This is not unlike natural selection: clones are selected for their fitness to attack the epitopes (stre... | 1 | Biochemistry |
Next-generation sequencing has enabled a genome-wide approach to identify DNA footprints. Open chromatin assays such as DNase-Seq and FAIRE-Seq have proven to provide a robust regulatory landscape for many cell types. However, these assays require some downstream bioinformatics analyses in order to provide genome-wide ... | 1 | Biochemistry |
The examples above define a standard drink as 0.6 fluid ounces (14 g or 17.7 mL) of ethanol, whereas other definitions exist, for example 10 grams of ethanol. | 1 | Biochemistry |
TIA1 or Tia1 cytotoxic granule-associated rna binding protein is a 3UTR mRNA binding protein that can bind the 5TOP sequence of 5'TOP mRNAs. It is associated with programmed cell death (apoptosis) and regulates alternative splicing of the gene encoding the Fas receptor, an apoptosis-promoting protein. Under stress con... | 1 | Biochemistry |
Two systems exist for the asymmetric hydrogenation of 2-substituted quinolines with isolated yields generally greater than 80% and ee values generally greater than 90%. The first is an iridium(I)/chiral phosphine/I system, first reported by Zhou et al.. While the first chiral phosphine used in this system was MeOBiPhep... | 0 | Organic Chemistry |
Life requires a loss of entropy, or disorder, when molecules organize themselves into living matter. The emergence of life and increased complexity does not contradict the second law of thermodynamics, which states that overall entropy never decreases, since a living organism creates order in some places (e.g. its livi... | 9 | Geochemistry |
There are a great variety of techniques to generate THz radiation and to detect THz fields. One can, e.g., use an antenna, a quantum-cascade laser, a free-electron laser, or optical rectification to produce well-defined THz sources. The resulting THz field can be characterized via its electric field E(t). Present-day e... | 7 | Physical Chemistry |
In Ellman's original paper, he prepared this reagent by oxidizing 2-nitro-5-chlorobenzaldehyde to the carboxylic acid, introducing the thiol via sodium sulfide, and coupling the monomer by oxidization with iodine. Today, this reagent is readily available commercially. | 1 | Biochemistry |
Mapping the relative orientation of crystalline grains and/or phases helps understand material texture at the micro and nano scales. In a transmission electron microscope, this is accomplished by recording a diffraction pattern at a large number of points (pixels) over a region of the crystalline specimen. By comparing... | 3 | Analytical Chemistry |
In attempts to raise the chemical and quantum yields of nitrobenzyl-based PPGs, several beneficial modifications have been identified. The largest increase in quantum yield and reaction rate can be achieved through substitution at the benzylic carbon. However, potential substitutions must leave one hydrogen atom so the... | 5 | Photochemistry |
KREEP, an acronym built from the letters K (the atomic symbol for potassium), REE (rare-earth elements) and P (for phosphorus), is a geochemical component of some lunar impact breccia and basaltic rocks. Its most significant feature is somewhat enhanced concentration of a majority of so-called "incompatible" elements (... | 9 | Geochemistry |
In the chemical industry, the term intermediate may also refer to the (stable) product of a reaction that is itself valuable only as a precursor chemical for other industries. A common example is cumene which is made from benzene and propylene and used to make acetone and phenol in the cumene process. The cumene itself... | 7 | Physical Chemistry |
Euhedral crystals (also known as idiomorphic or automorphic crystals) are those that are well-formed, with sharp, easily recognised faces. The opposite is anhedral (also known as xenomorphic or allotriomorphic): a rock with an anhedral texture is composed of mineral grains that have no well-formed crystal faces or cro... | 3 | Analytical Chemistry |
The experiment relies upon the interaction between optically-generated charge carriers and microwave frequency electromagnetic radiation. The most common approach is to use a resonant cavity. An oscillating voltage is produced using a signal generator such as a voltage controlled oscillator or a Gunn diode. The oscilla... | 7 | Physical Chemistry |
Fungi are amongst the primary saprotrophic organisms in an ecosystem, as they are efficient in the decomposition of matter. Wood-decay fungi, especially white rot, secretes extracellular enzymes and acids that break down lignin and cellulose, the two main building blocks of plant fiber. These are long-chain organic (ca... | 2 | Environmental Chemistry |
The endophenotype concept has also been used in suicide studies. Personality characteristics can be viewed as endophenotypes that may exert a diathesis effect on an individual's susceptibility to suicidal behavior. Although the exact identification of these endophenotypes is controversial, certain traits such as impuls... | 2 | Environmental Chemistry |
Temperature ratings for insulations may vary based on what the overall thermocouple construction cable consists of.
Note: T300 is a new high-temperature material that was recently approved by UL for 300 °C operating temperatures. | 8 | Metallurgy |
The Bennett acceptance ratio method (BAR) is an algorithm for estimating the difference in free energy between two systems (usually the systems will be simulated on the computer).
It was suggested by Charles H. Bennett in 1976. | 7 | Physical Chemistry |
Dolly, a Finn-Dorset ewe, was the first mammal to have been successfully cloned from an adult somatic cell. Dolly was formed by taking a cell from the udder of her 6-year-old biological mother. Dollys embryo was created by taking the cell and inserting it into a sheep ovum. It took 435 attempts before an embryo was suc... | 1 | Biochemistry |
Brain-derived neurotrophic factor (BDNF) is also a myokine, though BDNF produced by contracting muscle is not released into circulation. Rather, BDNF produced in skeletal muscle appears to enhance the oxidation of fat. Skeletal muscle activation through exercise also contributes to an increase in BDNF secretion in the ... | 1 | Biochemistry |
In a hydrogen bond, the electronegative atom not covalently attached to the hydrogen is named the proton acceptor, whereas the one covalently bound to the hydrogen is named the proton donor. This nomenclature is recommended by the IUPAC. The hydrogen of the donor is protic and therefore can act as a Lewis acid and the ... | 6 | Supramolecular Chemistry |
Surprisal analysis was extended to better characterize and understand cellular processes, see figure, biological phenomena and human disease with reference to personalized diagnostics. Surprisal analysis was first utilized to identify genes implicated in the balance state of cells in vitro; the genes mostly present in ... | 7 | Physical Chemistry |
Whiting events have a unique effect on the waters around them. The fact that calcium carbonate clouds increase turbidity and light reflectance holds implications for organisms and processes that depend on light. In addition, whiting events can function as a transport mechanism for organic carbon to the benthic zone, wh... | 9 | Geochemistry |
The members of the order Pasteurellales are currently distinguished mainly based on their position in the branching of the 16srRNA tree. There are currently very few molecular markers known that can distinguish members of this order from other bacteria. A CSI approach was recently used to elucidate the phylogenetic rel... | 1 | Biochemistry |
Common roll-to-roll coating processes include:
* Air knife coating
* Anilox coater
* Flexo coater
* Gap Coating
** Knife-over-roll coating
* Gravure coating
* Hot melt coating- when the necessary coating viscosity is achieved by temperature rather than solution of the polymers etc. This method commonly implies slot-di... | 8 | Metallurgy |
The raw sequencing data is then processed through bioinformatics (e.g., the GemCode analysis software developed by 10x Genomics) to remove low-quality reads and to assign reads to their respective barcodes. Reads can be aligned to a reference genome or assembled de novo to generate long-range contigs. The read alignmen... | 1 | Biochemistry |
One of the most important advantages of Fourier-transform spectroscopy was shown by P. B. Fellgett, an early advocate of the method. The Fellgett advantage, also known as the multiplex principle, states that when obtaining a spectrum when measurement noise is dominated by detector noise (which is independent of the pow... | 7 | Physical Chemistry |
While the JamesonCell continued to expand in base metals concentrate cleaning, SX–EW electrolyte cleaning and coal fines recovery applications, it also found new applications in cleaning potash slimes and was adopted by the Philex Mining Corporation as the sole flotation machine for its Benguet copper concentrator. Thi... | 8 | Metallurgy |
In organic chemistry, isothiouronium is a functional group with the formula [RSC(NH)] (R = alkyl, aryl) and is the acid salt of isothiourea. The H centres can also be replaced by alkyl and aryl. Structurally, these cations resemble guanidinium cations. The CNS core is planar and the C–N bonds are short. | 0 | Organic Chemistry |
Contrary to the abundance of theoretical and experimental work on the MPI of rare gas atoms, the amount of research on the prediction of the rate of MPI of neutral molecules was scarce until recently. Walsh et al. have measured the MPI rate of some diatomic molecules interacting with a CO laser. They found that these ... | 7 | Physical Chemistry |
The chemical reaction for the dissolution of gold, the "Elsner equation", follows:
: 4Au + 8NaCN + O + 2HO → 4Na[Au(CN)] + 4NaOH
Potassium cyanide and calcium cyanide are sometimes used in place of sodium cyanide.
Gold is one of the few metals that dissolves in the presence of cyanide ions and oxygen. The soluble gold ... | 8 | Metallurgy |
The Creighton process involves the hydrogenation of a 6 carbon chain aldehyde. The reactant is 2,3,4,5,6-pentahydroxyhexanal (an aldehyde) and the product is 1,2,3,4,5,6-hexanehexol (an alcohol). The product thus has two more hydrogen atoms than the reactant: -CHO is replaced by -CHOH.
The Creighton process was patent... | 0 | Organic Chemistry |
Trace elements serve as regulators of biological processes in the ocean, influencing marine ecosystem dynamics and the carbon cycle. Despite this significance, knowledge of the marine biogeochemical cycles of these essential micronutrients is surprisingly incomplete. GEOTRACES is quantifying the supply, removal, inter... | 9 | Geochemistry |
The ammonia produced in neurons is fixed into α-ketoglutarate by the glutamate-dehydrogenase reaction to form glutamate, then transaminated by alanine aminotransferase into lactate-derived pyruvate to form alanine, which is exported to astrocytes. In the astrocytes, this process is then reversed, and lactate is transpo... | 1 | Biochemistry |
Several single nucleotide polymorphisms within the TCF7L2 gene have been associated with type 2 diabetes. Studies conducted by Ravindranath Duggirala and Michael Stern at The University of Texas Health Science Center at San Antonio were the first to identify strong linkage for type 2 diabetes at a region on Chromosome ... | 1 | Biochemistry |
The term antiaromaticity was first proposed by Ronald Breslow in 1967 as "a situation in which a cyclic delocalisation of electrons is destabilising". The IUPAC criteria for antiaromaticity are as follows:
#The molecule must be cyclic.
#The molecule must be planar.
#The molecule must have a complete conjugated π-electr... | 7 | Physical Chemistry |
Human milk oligosaccharides can be synthesized in large quantities using precision industrial fermentation methods e.g. by the commonly used, non-pathogenic bacteria Escherichia coli. During the fermentation process the bacteria are fed with a carbon-source (e.g. glucose), salts, minerals and trace elements under asept... | 0 | Organic Chemistry |
TNP-ATP should be stored at −20 degrees Celsius, in the dark, and used under minimal lighting conditions. When in solution, TNP-ATP has a shelf-life of about 30 days. | 7 | Physical Chemistry |
Through the process of alternative splicing, the CKLF gene encodes 4 CKLF protein isoforms, i.e. proteins made from different areas of the same gene. These isoforms are 1) CKLF1 and CKLF3 proteins that consist of 99 and 67 amino acids, respectively, and are secreted from their parent cells and 2) CKLF2 (which is the f... | 1 | Biochemistry |
Cytochrome c is an essential component of the respiratory electron transport chain in mitochondria. The heme group of cytochrome c accepts electrons from the bc Complex III and transports them to Complex IV, while it transfers energy in the opposite direction.
Cytochrome c can also catalyze several redox reactions such... | 1 | Biochemistry |
In 2016, microcystin had been found in San Francisco Bay Area shellfish in seawater, apparently from freshwater runoff, exacerbated by drought. | 2 | Environmental Chemistry |
Theories for the origin of homochirality in the molecules of life can be classified as deterministic or based on chance depending on their proposed mechanism. If there is a relationship between cause and effect — that is, a specific chiral field or influence causing the mirror symmetry breaking — the theory is classifi... | 4 | Stereochemistry |
The screw axis appears in the dual quaternion formulation of a spatial displacement . The dual quaternion is constructed from the dual vector defining the screw axis and the dual angle , where φ is the rotation about and d the slide along this axis, which defines the displacement D to obtain,
A spatial displacement of... | 3 | Analytical Chemistry |
Molecular models of DNA structures are representations of the molecular geometry and topology of deoxyribonucleic acid (DNA) molecules using one of several means, with the aim of simplifying and presenting the essential, physical and chemical, properties of DNA molecular structures either in vivo or in vitro. These r... | 4 | Stereochemistry |
Although Golden Gate Cloning speeds up multisegment cloning, careful design of donor and recipient plasmids is required. Scientists at New England Biolabs have successfully demonstrated the assembly of 35 fragments via a single-tube Golden Gate Assembly reaction. Critical to this method of assembly, the vector backbone... | 1 | Biochemistry |
During DNA damage or cellular stress PARPs are activated, leading to an increase in the amount of poly(ADP-ribose) and a decrease in the amount of NAD. For over a decade it was thought that PARP1 was the only poly(ADP-ribose)polymerase in mammalian cells, therefore this enzyme has been the most studied. Caspases are a ... | 1 | Biochemistry |
A selenonic acid is an organoselenium compound containing the SeOH functional group. Selenonic acids are the selenium analogs of sulfonic acids. Examples of the acid are rare. Benzeneselenonic acid is a white solid. It can be prepared by the oxidation of benzeneselenol. | 0 | Organic Chemistry |
In silico experiments with Monte Carlo simulations demonstrated that both SPINA-GT and SPINA-GD can be estimated with sufficient reliability, even if laboratory assays have limited accuracy. This was confirmed by longitudinal in vivo studies that showed that GT has lower intraindividual variation (i.e. higher reliabili... | 1 | Biochemistry |
Several techniques exist to produce pre-alloyed powder, such as Grade 5. In the hydride-dehydride process feedstock such as solid scrap, billet or machined turnings are processed to remove contaminants, hydrogenated to produce brittle material then ground under argon in a vibratory ball mill, typically at 400 °C for 4 ... | 8 | Metallurgy |
As indicated in the Figure above, captioned "Demethylation of 5-methylcytosine," the first step in active demethylation is a TET oxidation of 5-methylcytosine (5mC) to 5-hydroxymethylcytosine (5hmC). The demethylation process, in some tissues and at some genome locations, may stop at that point. As reviewed by Uribe-Le... | 1 | Biochemistry |
Andesitic magma is an intermediate magma and is approximately evenly dispersed regarding iron, magnesium, calcium, sodium, and potassium. The silica composition of andesitic magma ranges from 55 - 65 wt.%. It forms in temperatures ranging from approximately 1470 °F to 1830 °F. Andesitic magma has an intermediate visco... | 9 | Geochemistry |
In DVD drives, the signal produced from the disc is a reflection of the addressing laser beam, and is therefore very intense. For 3D optical storage however, the signal must be generated within the tiny volume that is addressed, and therefore it is much weaker than the laser light. In addition, fluorescence is radiated... | 5 | Photochemistry |
In the 1950s, Norwegian scientist Scholander set out to explain how Arctic fish can survive in water colder than the freezing point of their blood. His experiments led him to believe there was “antifreeze” in the blood of Arctic fish. Then in the late 1960s, animal biologist Arthur DeVries was able to isolate the anti... | 1 | Biochemistry |
In 1967, Charles Pedersen, who was a chemist working at DuPont, discovered a simple method of synthesizing a crown ether when he was trying to prepare a complexing agent for divalent cations. His strategy entailed linking two catecholate groups through one hydroxyl on each molecule. This linking defines a polydentate l... | 6 | Supramolecular Chemistry |
:The following carbon numbering system of porphyrins is an older numbering used by biochemists and not the 1–24 numbering system recommended by IUPAC, which is shown in the table above.
*Heme l is the derivative of heme B which is covalently attached to the protein of lactoperoxidase, eosinophil peroxidase, and thyroid... | 1 | Biochemistry |
The L-alanine derivative β-methylamino-L-alanine (BMAA) has long been identified as a neurotoxin which was first associated with the amyotrophic lateral sclerosis/parkinsonism–dementia complex (Lytico-bodig disease) in the Chamorro people of Guam. The widespread occurrence of BMAA can be attributed to cyanobacteria whi... | 1 | Biochemistry |
Because gas molecules diffract electrons and affect the quality of the electron gun, RHEED experiments are performed under vacuum. The RHEED system must operate at a pressure low enough to prevent significant scattering of the electron beams by gas molecules in the chamber. At electron energies of 10keV, a chamber pres... | 3 | Analytical Chemistry |
The neuroprostanes are prostaglandin-like compounds formed in vivo from the free radical-catalyzed peroxidation
of essential fatty acids (primarily docosahexaenoic acid) without the direct action of cyclooxygenase (COX) enzymes. The result is the formation of isoprostane-like compounds F4-, D4-, E4-, A4-, and J4-neur... | 1 | Biochemistry |
The mechanism of the Kröhnke pyridine synthesis begins with enolization of α-pyridinium methyl ketone 4 followed by 1,4-addition to the α, β-unsaturated ketone 5 to form the Michael adduct 6, which immediately tautomerizes to the 1,5-dicarbonyl 7. Addition of ammonia to 7 followed by dehydration via 8 generates the imi... | 0 | Organic Chemistry |
The TET enzymes are a family of ten-eleven translocation (TET) methylcytosine dioxygenases. They are instrumental in DNA demethylation. 5-Methylcytosine (see first Figure) is a methylated form of the DNA base cytosine (C) that often regulates gene transcription and has several other functions in the genome.
Demethyl... | 1 | Biochemistry |
The first isolation of deoxyribonucleic acid (DNA) was done in 1869 by Friedrich Miescher. DNA extraction is the process of isolating DNA from the cells of an organism isolated from a sample, typically a biological sample such as blood, saliva, or tissue. It involves breaking open the cells, removing proteins and othe... | 1 | Biochemistry |
Alkynylation finds use in synthesis of pharmaceuticals, particularly in the preparation of steroid hormones. For example, ethynylation of 17-ketosteroids produces important contraceptive medications known as progestins. Examples include drugs such as Norethisterone, Ethisterone, and Lynestrenol. Hydrogenation of these ... | 0 | Organic Chemistry |
The chloroplast stroma contains many proteins, though the most common and important is RuBisCO, which is probably also the most abundant protein on the planet. RuBisCO is the enzyme that fixes CO into sugar molecules. In plants, RuBisCO is abundant in all chloroplasts, though in plants, it is confined to the bundle s... | 5 | Photochemistry |
Nevertheless, it was known that yeast extracts can ferment sugar even in the absence of living yeast cells. While studying this process in 1897, the German chemist and zymologist Eduard Buchner of Humboldt University of Berlin, Germany, found that sugar was fermented even when there were no living yeast cells in the mi... | 1 | Biochemistry |
In organic chemistry, the Cieplak effect is a predictive model to rationalize why nucleophiles preferentially add to one face of a carbonyl over another. Proposed by Andrzej Stanislaw Cieplak in 1980, it correctly predicts results that could not be justified by the other standard models at the time, such as the Cram an... | 0 | Organic Chemistry |
Anabolism () is the set of metabolic pathways that construct macromolecules like DNA or RNA from smaller units. These reactions require energy, known also as an endergonic process. Anabolism is the building-up aspect of metabolism, whereas catabolism is the breaking-down aspect. Anabolism is usually synonymous with bio... | 1 | Biochemistry |
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