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Many types of tear gas and other riot control agents have been produced with effects ranging from mild tearing of the eyes to immediate vomiting and prostration. CN and CS are the most widely used and known, but around 15 different types of tear gas have been developed worldwide, e.g. adamsite or bromoacetone, CNB, and CNC. CS has become the most popular due to its strong effect. The effect of CS on a person will depend on whether it is packaged as a solution or used as an aerosol. The size of solution droplets and the size of the CS particulates after evaporation are factors determining its effect on the human body.
The chemical reacts with moisture on the skin and in the eyes, causing a burning sensation and the immediate forceful and uncontrollable shutting of the eyes. Effects usually include tears streaming from the eyes, profuse coughing, exceptional nasal discharge that is full of mucus, burning in the eyes, eyelids, nose and throat areas, disorientation, dizziness and restricted breathing. It will also burn the skin where sweaty or sunburned. In highly concentrated doses, it can also induce severe coughing and vomiting. Most of the immediate effects wear off within a few hours (such as exceptional nasal discharge and profuse coughing), although respiratory, gastrointestinal, and oral symptoms may persist for months. Excessive exposure can cause chemical burns resulting in permanent scarring.
Adults exposed to tear gas during the 2020 protests in Portland Oregon (USA) also reported menstrual changes (899; 54.5% of 1650 female respondents). Exposure to tear gas is associated with avoidable healthcare utilization. | 1 | Biochemistry |
In organic chemistry, an epoxide is a cyclic ether, where the ether forms a three-atom ring: two atoms of carbon and one atom of oxygen. This triangular structure has substantial ring strain, making epoxides highly reactive, more so than other ethers. They are produced on a large scale for many applications. In general, low molecular weight epoxides are colourless and nonpolar, and often volatile. | 0 | Organic Chemistry |
According to the chemiosmotic coupling hypothesis, proposed by Nobel Prize in Chemistry winner Peter D. Mitchell, the electron transport chain and oxidative phosphorylation are coupled by a proton gradient across the inner mitochondrial membrane. The efflux of protons from the mitochondrial matrix creates an electrochemical gradient (proton gradient). This gradient is used by the FF ATP synthase complex to make ATP via oxidative phosphorylation. ATP synthase is sometimes described as Complex V of the electron transport chain. The F component of ATP synthase acts as an ion channel that provides for a proton flux back into the mitochondrial matrix. It is composed of a, b and c subunits. Protons in the inter-membrane space of mitochondria first enter the ATP synthase complex through an a subunit channel. Then protons move to the c subunits. The number of c subunits determines how many protons are required to make the F turn one full revolution. For example, in humans, there are 8 c subunits, thus 8 protons are required. After c subunits, protons finally enter the matrix through an a subunit channel that opens into the mitochondrial matrix. This reflux releases free energy produced during the generation of the oxidized forms of the electron carriers (NAD and Q) with energy provided by O. The free energy is used to drive ATP synthesis, catalyzed by the F component of the complex.<br>Coupling with oxidative phosphorylation is a key step for ATP production. However, in specific cases, uncoupling the two processes may be biologically useful. The uncoupling protein, thermogenin—present in the inner mitochondrial membrane of brown adipose tissue—provides for an alternative flow of protons back to the inner mitochondrial matrix. Thyroxine is also a natural uncoupler. This alternative flow results in thermogenesis rather than ATP production. | 1 | Biochemistry |
microRNA (miRNA) plays an important role in regulating gene expression. Majority of miRNAs are transcribed from DNA sequences into primary miRNAs. These primary miRNAs are further processed into precursor miRNAs, and finally into mature miRNAs. The miRNAs in most cases interact with the 3’ UTR region of target to induce mRNA degradation and translational repression. Interactions of miRNAs with other regions, including the 5’ UTR, coding sequence, and gene promoters have also been reported. Under certain conditions, miRNAs are also able to activate translation or regulate transcription, but this is dependent on factors such as location of the effect. This process of interaction is very dynamic and dependent on multiple factors. | 1 | Biochemistry |
On the basis of experimental and computational studies, the stabilization arising from an agostic interaction is estimated to be 10–15 kcal/mol. Recent calculations using compliance constants point to a weaker stabilisation (<10 kcal/mol). Thus, agostic interactions are stronger than most hydrogen bonds. Agostic bonds sometimes play a role in catalysis by increasing rigidity in transition states. For instance, in Ziegler–Natta catalysis the highly electrophilic metal center has agostic interactions with the growing polymer chain. This increased rigidity influences the stereoselectivity of the polymerization process. | 0 | Organic Chemistry |
ASF/SF2, in the presence of elF4E, promotes the initiation of translation of ribosome-bound mRNA by suppressing the activity of 4E-BP and recruiting molecules for further regulation of translation. ASF/SF2 interacts with the nuclear export protein TAP in a regulated manner, controlling the export of mature mRNA from the nucleus. An increase in cellular ASF/SF2 also will increase the efficiency of nonsense-mediated mRNA decay (NMD), favoring NMD that occurs before mRNA release from the nucleus over NMD that occurs after mRNA export from the nucleus to the cytoplasm. This shift in NMD caused by increased ASF/SF2 is accompanied by overall enhancement of the pioneer round of translation, through elF4E-bound mRNA translation and subsequent translationally active ribosomes, increased association of pioneer translation initiation complexes with ASF/SF2, and increased levels of active TAP. | 1 | Biochemistry |
Copepods (; meaning "oar-feet") are a group of small crustaceans found in nearly every freshwater and saltwater habitat. Some species are planktonic (living in the water column), some are benthic (living on the sediments), a number of species have parasitic phases, and some continental species may live in limnoterrestrial habitats and other wet terrestrial places, such as swamps, under leaf fall in wet forests, bogs, springs, ephemeral ponds, puddles, damp moss, or water-filled recesses of plants (phytotelmata) such as bromeliads and pitcher plants. Many live underground in marine and freshwater caves, sinkholes, or stream beds. Copepods are sometimes used as biodiversity indicators.
As with other crustaceans, copepods have a larval form. For copepods, the egg hatches into a nauplius form, with a head and a tail but no true thorax or abdomen. The larva molts several times until it resembles the adult and then, after more molts, achieves adult development. The nauplius form is so different from the adult form that it was once thought to be a separate species. The metamorphosis had, until 1832, led to copepods being misidentified as zoophytes or insects (albeit aquatic ones), or, for parasitic copepods, fish lice. | 2 | Environmental Chemistry |
Gene symbols are italicised and all letters are in lowercase (shh). Protein designations are different from their gene symbol; they are not italicised, and all letters are in uppercase (SHH). | 1 | Biochemistry |
The non-stoichiometric cycles with a perovskite ABO can be describes with the following reactions:
::Reduction reaction: ABO → ABO + δ/2 O
::Oxidation reaction: ABO + δ HO → ABO + δ H
The reduction thermodynamics of perovskite makes it more favorable during the reduction half-cycle, during which more oxygen is produced; however, the oxidation thermodynamics proves less suitable, and sometimes perovskite is not completely oxidized. The two atomic sites, A and B, offer more doping possibilities and a much larger potential for different configurations. | 7 | Physical Chemistry |
Using high pressure, pressure injection cells are used for two applications: densely packing nanopore capillary columns (micro-columns) with solid-phase particles for use in LC/MS analysis; and precisely infusing microliter samples directly from microcentrifuge tubes into mass spectrometers without additional transfers, wasted sample, or contact with metallic surfaces which adsorb some negatively charged molecules such as phosphopeptides. | 3 | Analytical Chemistry |
Peter Jonathan Rutledge is a New Zealand chemist and professor at the School of Chemistry, University of Sydney. His research has focused on drug development for tuberculosis, antibiotics, and metal sensing. He has engaged in some research activity on catalysis. | 0 | Organic Chemistry |
DNA methyltransferases are inhibited by SAH. Two S-adenosyl--homocysteine cofactor products can bind the active site of DNA methyltransferase 3B and prevent the DNA duplex from binding to the active site, which inhibits DNA methylation. | 1 | Biochemistry |
Another difference between eukaryotes and prokaryotes is mRNA transport. Because eukaryotic transcription and translation is compartmentally separated, eukaryotic mRNAs must be exported from the nucleus to the cytoplasm—a process that may be regulated by different signaling pathways. Mature mRNAs are recognized by their processed modifications and then exported through the nuclear pore by binding to the cap-binding proteins CBP20 and CBP80, as well as the transcription/export complex (TREX). Multiple mRNA export pathways have been identified in eukaryotes.
In spatially complex cells, some mRNAs are transported to particular subcellular destinations. In mature neurons, certain mRNA are transported from the soma to dendrites. One site of mRNA translation is at polyribosomes selectively localized beneath synapses. The mRNA for Arc/Arg3.1 is induced by synaptic activity and localizes selectively near active synapses based on signals generated by NMDA receptors. Other mRNAs also move into dendrites in response to external stimuli, such as β-actin mRNA. For export from the nucleus, actin mRNA associates with ZBP1 and later with 40S subunit. The complex is bound by a motor protein and is transported to the target location (neurite extension) along the cytoskeleton. Eventually ZBP1 is phosphorylated by Src in order for translation to be initiated. In developing neurons, mRNAs are also transported into growing axons and especially growth cones. Many mRNAs are marked with so-called "zip codes", which target their transport to a specific location. mRNAs can also transfer between mammalian cells through structures called tunneling nanotubes. | 1 | Biochemistry |
The primary function of lysosomal lipase is to hydrolyze lipids such as triglycerides and cholesterol. These fats are transported and degraded into free fatty acids. Lysosomal lipases function optimally at an acidic pH which are complementary with the environment found in the lysosomal lumen. These enzymes were believed to only hydrolyze the lipids found in organelle membranes and extracellular lipids. However, recent studies suggest that lysosomal lipases also play a significant role in the degradation of cytosolic lipids, a characteristic that was previously limited to neutral lipases. The ability of the lysosome to degrade a diverse set of cargo is attributed to the lysosomal lipase and other soluble hydrolases. These enzymes include sulphatases, phosphatases, peptidases, glycosidases, and nucleases.
The biochemical role of these enzymes are observed in various pathways, specifically in lipid catabolism. At the intracellular level, the byproducts released by the lysosomal lipase are recycled for membrane assembly and energy production. In addition, these enzymes participate in the production of specific fatty acids necessary for the metabolic reprogramming of CD8+ memory T cells, macrophage alternative activation, and lipid mediator synthesis. As observed, the degradation of these lipids are essential to maintain homeostasis within the body. The absence or decreased activity of this enzyme could lead to various metabolic disorders. | 1 | Biochemistry |
Calixarenes and related formaldehyde-arene condensates are one class of hosts that form inclusion compounds. One famous illustration is the adduct with cyclobutadiene, which otherwise is unstable. | 6 | Supramolecular Chemistry |
In organic chemistry, the sulfonamide functional group (also spelled sulphonamide) is an organosulfur group with the structure . It consists of a sulfonyl group () connected to an amine group (). Relatively speaking this group is unreactive. Because of the rigidity of the functional group, sulfonamides are typically crystalline; for this reason, the formation of a sulfonamide is a classic method to convert an amine into a crystalline derivative which can be identified by its melting point. Many important drugs contain the sulfonamide group.
A sulfonamide (compound) is a chemical compound that contains this group. The general formula is or , where each R is some organic group; for example, "methanesulfonamide" (where R = methane, R' = R" = hydrogen) is . Any sulfonamide can be considered as derived from a sulfonic acid by replacing a hydroxyl group () with an amine group.
In medicine, the term "sulfonamide" is sometimes used as a synonym for sulfa drug, a derivative or variation of sulfanilamide. The first sulfonamide was discovered in Germany in 1932. | 0 | Organic Chemistry |
There are two main advantages to CRDS over other absorption methods:
First, it is not affected by fluctuations in the laser intensity. In most absorption measurements, the light source must be assumed to remain steady between blank (no analyte), standard (known amount of analyte), and sample (unknown amount of analyte). Any drift (change in the light source) between measurements will introduce errors. In CRDS, the ringdown time does not depend on the intensity of the laser, so fluctuations of this type are not a problem. Independency from laser intensity makes CRDS needless to any calibration and comparison with standards.
Second, it is very sensitive due to its long pathlength. In absorption measurements, the smallest amount that can be detected is proportional to the length that the light travels through a sample. Since the light reflects many times between the mirrors, it ends up traveling long distances. For example, a laser pulse making 500 round trips through a 1-meter cavity will effectively have traveled through 1 kilometer of sample.
Thus, the advantages include:
*High sensitivity due to the multipass nature (i.e. long pathlength) of the detection cell.
*Immunity to shot variations in laser intensity due to the measurement of a rate constant.
*Wide range of use for a given set of mirrors; typically, ±5% of the center wavelength.
*High throughput, individual ring down events occur on the millisecond time scale.
*No need for a fluorophore, which makes it more attractive than laser-induced fluorescence (LIF) or resonance-enhanced multiphoton ionization (REMPI) for some (e.g. rapidly predissociating) systems.
*Commercial systems available. | 7 | Physical Chemistry |
The development, differentiation and growth of cells and tissues require precisely regulated patterns of gene expression. Enhancers work as cis-regulatory elements to mediate both spatial and temporal control of development by turning on transcription in specific cells and/or repressing it in other cells. Thus, the particular combination of transcription factors and other DNA-binding proteins in a developing tissue controls which genes will be expressed in that tissue. Enhancers allow the same gene to be used in diverse processes in space and time. | 1 | Biochemistry |
An example of this is the Coulter counter, which measures the momentary changes in the conductivity of a liquid passing through an orifice that take place when individual non-conducting particles pass through. The particle count is obtained by counting pulses. This pulse is proportional to the volume of the sensed particle.
Advantages: very small sample aliquots can be examined.
Disadvantages: sample must be dispersed in a liquid medium... some particles may (partially or fully) dissolve in the medium altering the size distribution. The results are only related to the projected cross-sectional area that a particle displaces as it passes through an orifice. This is a physical diameter, not really related to mathematical descriptions of particles (e.g. terminal settling velocity). | 7 | Physical Chemistry |
Schoell was born in Germany, although the bulk of his career and adult life he has spent in the United States. Since retiring, Schoell resides in California. Aside from his research, Schoell has experience in winemaking. | 9 | Geochemistry |
Trifluoroacetic acid (TFA) is an organofluorine compound with the chemical formula CFCOH. It is a haloacetic acid, with all three of the acetyl groups hydrogen atoms replaced by fluorine atoms. It is a colorless liquid with a vinegar-like odor. TFA is a stronger acid than acetic acid, having an acid ionisation constant, K', that is approximately 34,000 times higher, as the highly electronegative fluorine atoms and consequent electron-withdrawing nature of the trifluoromethyl group weakens the oxygen-hydrogen bond (allowing for greater acidity) and stabilises the anionic conjugate base. TFA is widely used in organic chemistry for various purposes. | 0 | Organic Chemistry |
William Klyne (March 23, 1913, in Enfield, Middlesex – November 13, 1977) was an organic chemist known for his work in steroids and stereochemistry — a field in which he was a "pioneer", and in which Ernest Eliel and Norman Allinger described him as "one of the world's experts".
In 1946, he gained a PhD from the University of Edinburgh with a thesis entitled “The steroid sulphates: studies on the conjugated sulphates of mare’s pregnancy urine".
Klyne taught at Westfield College, University of London, where he served as dean of science from 1971 to 1973, and as vice-principal from 1973 to 1976. He also served on the editorial board of the Biochemical Society from 1950 to 1955, and on IUPACs nomenclature committee from 1971 until his death. As well, he established and maintained the Medical Research Councils Steroid Reference Collection, and wrote several textbooks, including The Chemistry of Steroids (1957) and Atlas of Stereochemical Correlations (1974). | 4 | Stereochemistry |
Discodermolide competes with paclitaxel for microtubule binding, but with higher affinity and is also effective in paclitaxel- and in epothilone-resistant cancer cells. Discodermolide also seems to demonstrate a remarkably consistent 3D molecular conformation in the solid-state, in solution and when bound to tubulin; molecules with the conformational flexibility of discodermolide usually present very different conformations in different environments. | 0 | Organic Chemistry |
Forensic science, also known as criminalistics, is the application of science principles and methods to support legal decision-making in matters of criminal and civil law.
During criminal investigation in particular, it is governed by the legal standards of admissible evidence and criminal procedure. It is a broad field utilizing numerous practices such as the analysis of DNA, fingerprints, bloodstain patterns, firearms, ballistics, toxicology, and fire debris analysis.
Forensic scientists collect, preserve, and analyze evidence during the course of an investigation. While some forensic scientists travel to the scene of the crime to collect the evidence themselves, others occupy a laboratory role, performing analysis on objects brought to them by other individuals. Others are involved in analysis of financial, banking, or other numerical data for use in financial crime investigation, and can be employed as consultants from private firms, academia, or as government employees.
In addition to their laboratory role, forensic scientists testify as expert witnesses in both criminal and civil cases and can work for either the prosecution or the defense. While any field could technically be forensic, certain sections have developed over time to encompass the majority of forensically related cases. | 3 | Analytical Chemistry |
Cyanohydrins were first prepared by the addition of HCN and a catalyst (base or enzyme) to the corresponding carbonyl. On a laboratory scale the use of HCN (toxic) is largely not encouraged, for this reason other less dangerous cyanation reagents are sought out. In situ formation of HCN can be sourced using precursors such as acetone cyanohydrin. Alternatively, cyano-silyl derivatives such as TMS-CN allows for both the cyanation and protection in one step without the need for HCN. Similar procedures relying on ester, phosphate and carbonate formation have been reported. | 0 | Organic Chemistry |
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Carotenoid oxygenases are a family of enzymes involved in the cleavage of carotenoids to produce, for example, retinol, commonly known as vitamin A. This family includes an enzyme known as RPE65 which is abundantly expressed in the retinal pigment epithelium where it catalyzed the formation of 11-cis-retinol from all-trans-retinyl esters.
Carotenoids such as beta-carotene, lycopene, lutein and beta-cryptoxanthin are produced in plants and certain bacteria, algae and fungi, where they function as accessory photosynthetic pigments and as scavengers of oxygen radicals for photoprotection. They are also essential dietary nutrients in animals. Carotenoid oxygenases cleave a variety of carotenoids into a range of biologically important products, including apocarotenoids in plants that function as hormones, pigments, flavours, floral scents and defence compounds, and retinoids in animals that function as vitamins, chromophores for opsins and signalling molecules. Examples of carotenoid oxygenases include:
* Beta-carotene 15,15'-monooxygenase (BCO1; ) from animals, which cleaves beta-carotene symmetrically at the central double bond to yield two molecules of retinal.
* Beta-carotene-9,10-dioxygenase (BCO2) from animals, which cleaves beta-carotene asymmetrically to apo-10'-beta-carotenal and beta-ionone, the latter being converted to retinoic acid. Lycopene is also oxidatively cleaved.
* 9-cis-epoxycarotenoid dioxygenase from plants, which cleaves 9-cis xanthophylls to xanthoxin, a precursor of the hormone abscisic acid. Yellow skin, which is a common phenotype in domestic chicken, is influenced by the accumulation of carotenoids in skin due to absence of beta-carotene dioxygenase 2 (BCDO2) enzyme. Inhibition of expression of BCO2 gene is caused by a regulatory mutation.
* Apocarotenoid-15,15'-oxygenase from bacteria and cyanobacteria, which converts beta-apocarotenals rather than beta-carotene into retinal. This protein has a seven-bladed beta-propeller structure.
* Retinal pigment epithelium 65 kDa protein (RPE65) from vertebrates which is important for the production of 11-cis retinal during visual opsin regeneration.
Members of the family use an iron(II) active center, usually held by four histidines. | 2 | Environmental Chemistry |
The most direct way of measuring the activity of a volatile species is to measure its equilibrium partial vapor pressure. For water as solvent, the water activity a is the equilibrated relative humidity. For non-volatile components, such as sucrose or sodium chloride, this approach will not work since they do not have measurable vapor pressures at most temperatures. However, in such cases it is possible to measure the vapor pressure of the solvent instead. Using the Gibbs–Duhem relation it is possible to translate the change in solvent vapor pressures with concentration into activities for the solute.
The simplest way of determining how the activity of a component depends on pressure is by measurement of densities of solution, knowing that real solutions have deviations from the additivity of (molar) volumes of pure components compared to the (molar) volume of the solution. This involves the use of partial molar volumes, which measure the change in chemical potential with respect to pressure.
Another way to determine the activity of a species is through the manipulation of colligative properties, specifically freezing point depression. Using freezing point depression techniques, it is possible to calculate the activity of a weak acid from the relation,
where is the total equilibrium molality of solute determined by any colligative property measurement (in this case ), is the nominal molality obtained from titration and is the activity of the species.
There are also electrochemical methods that allow the determination of activity and its coefficient.
The value of the mean ionic activity coefficient of ions in solution can also be estimated with the Debye–Hückel equation, the Davies equation or the Pitzer equations. | 7 | Physical Chemistry |
Schymanski's first research publications were from her undergraduate work when she worked on developing new metal-containing polymers which resulted in three lead author publications.
As a graduate student, Schymanski started using information on the fragmentation pattern of organic compounds as a means to expand the identification of unknown compounds. Schymanski applied these novel methods to the identification of unknown organic compounds found in wastewater, and used data collectively gathered by the NORMAN Association to define barriers to the identification of unknown organic compounds in water. Identifying and tracking unknown organic compounds continues to be an avenue of research pursued by Schymanski and she is a co-author on a 2014 textbook describing these methods.
In 2012, Schymanski and Steffen Neumann started the Critical Assessment of Small Molecule Identification (CASMI) contest that provided researchers with information about unknown organic compounds and challenged them to use automated computational tools identify the unknown compounds. The Metabolomics Society highlighted the 2012 contest in their newsletter. There have been multiple iterations of the contest, and Schymanski examined the results of the 2016 contest.
Schymanski's research focuses on characterizing organic compounds found in wastewater and exposomics, or the science of compounds that people are exposed to over their lifetimes. Schymanski has developed a subset of PubChem for exposomics, PubChemLite, which can be annotated to increase ability of researchers to identify unknown environmental compounds. Within this field, Schymanski is working to automate the identification of a group of fluorinated compounds called ‘per- and poly-fluoroalkyl substances’ (PFASs) in order to increase the ability of researchers to find unknown PFAS in the environment.
Schymanski is an advocate for open science and data sharing. Within the NORMAN network, a collaborative activity across Europe, North America, and Asia, Schymanski worked in 2011 with the team that established NORMAN MassBank, which was a community-driven project to gather information about small molecules. In 2015, Schymanski expanded this type of data with the NORMAN Suspect List Exchange. Schymanski has also worked to develop computational tools that allow the processing of complex high resolution mass spectrometry data and sought to establish standards to consider the quality of the mass spectrometry data. Schymanskis 2014 publication in Environmental Science & Technology' establishes a means to estimate confidence in the quality of unknown organic compound identifications and, as of 2021, has over 1000 citations. In 2018, Schymanski considered this paper her greatest achievement because it established the standard for compound identification in metabolomics and encouraged community conversation about future of these tools. | 0 | Organic Chemistry |
Equilibrium isotope fractionation is the partial separation of isotopes between two or more substances in chemical equilibrium. Equilibrium fractionation is strongest at low temperatures, and (along with kinetic isotope effects) forms the basis of the most widely used isotopic paleothermometers (or climate proxies): D/H and O/O records from ice cores, and O/O records from calcium carbonate. It is thus important for the construction of geologic temperature records. Isotopic fractionations attributed to equilibrium processes have been observed in many elements, from hydrogen (D/H) to uranium (U/U). In general, the light elements (especially hydrogen, boron, carbon, nitrogen, oxygen and sulfur) are most susceptible to fractionation, and their isotopes tend to be separated to a greater degree than heavier elements. | 9 | Geochemistry |
As reagent testing has become more popular, vendors have begun to offer a greater range of tests. This increases the likelihood that a substance might have a unique profile of results, making the tests more useful.
Other reagents are discussed in scientific literature, but limited applications mean they may not be sold for consumer testing.
The National Institute of Justice provides information about "Color Test Reagents/Kits for Preliminary Identification
of Drugs of Abuse" in NIJ Standard–0604.01.
Several products are in early phases of development that are intended to allow their users to covertly detect (without using droppers, etc.) date-rape drugs, for instance reusable straws with components that change color in the presence of GHB, Rohypnol, or ketamine – see . | 3 | Analytical Chemistry |
The use of organometallic structures led by π–metal bonding plays an enormous role in the catalysis of organic reactions. The Stille reaction is a widely known and important reaction in organic synthesis. π interactions with the Pd catalyst in this reaction are almost necessary in pushing this reaction to completion (alkyl groups transfer is rather slow).
Other widely known reactions based on π–metal catalysis interactions are:
*Heck reaction
*Hiyama coupling
*Kumada coupling
*Negishi coupling
*Petasis reaction
*Sonogashira coupling
*Suzuki reaction.
π–metal interactions can also be involved directly with the function of ligands on the catalyst. Chemistry involving nickel catalysis of Suzuki reactions was greatly affected by pyrazoles and pyrazolates acting as coplanar ligand. The π interactions tied multiple pyrazoles and pyrazolates together around the nickel metal to cause reaction results.
Another π metal interaction directly involved with catalysis involves π stacking. Ferrocene is the standard example where the metal (iron) is trapped in between two cyclopentadienyl ligands. These interactions are commonly referred to as sandwich compounds.
Specific research
Due to reasons explained earlier in the article, the bonding between a nucleophilic olefin and an electrophilic palladium(II) leaves olefin susceptible to nucleophilic attack. This is true if the olefin is coordinated around Pd as the corner of a square planar complex or as the side of a cationic 18-electron Pd complex. In both cases electron donating groups on the olefin stabilize the complex, but anionic electron donors actually destabilized the complex in the case of the 18-electron Pd complex. The authors of this research proposed that when the olefin π bond is aligned on the side of the square planar Pd complex, the π* backfilling of electron density from Pd to olefin is enhanced because the more electron withdrawing orbital of the π complex can overlap better with the electron donating orbital of Pd. | 6 | Supramolecular Chemistry |
Aptamers, single-stranded RNA and DNA sequences, bind to an analyte and change their conformation. They function as nucleic acids selectively binding molecules such as proteins, bacteria cells, metal ions, etc. Aptamers can be developed to have precise specificity to bind to a desired target. Aptamers change conformation upon binding, altering the electrochemical properties which can be measured. The Systematic Evolution of Ligands by Exponential Enrichment (SELEX) process generates aptamers. Electrochemical aptamer-based (E-AB) biosensors is a device that takes advantage of the electrochemical and biological properties of aptamers to take real time, in vivo measurements.
An electrochemical aptamer-based (E-AB) biosensor to generates an electrochemical signal in response to specific target binding in vivo The signal is measured by a change in Faradaic current passed through an electrode. E-AB sensors are advantageous over previously reported aptamer-based sensors, such as fluorescence generating aptamers, due to their ability to detect target binding in vivo with real-time measurements. An E-AB sensor is composed of a three-electrode cell: an interrogating electrode, a reference electrode, and a counter electrode. A signal is generated within the electrochemical cell then measured and analyzed by a potentiostat. Several biochemical and electrochemical parameters optimize signal gain for E-AB biosensors. The density packing of DNA or RNA aptamers, the ACV frequency administered by the potentiostat, and the chemistry of the self assembling monolayer (SAM) are all factors that determine signal gain as well as the signal to noise ratio of target binding. E-AB biosensors provide a promising mechanism for in-situ sensing, feedback-controlled drug administration, and cancer biomarkers. | 7 | Physical Chemistry |
Indoor tanning is most popular with white females, 16–25 years old, with low-to-moderate skin sensitivity, who know other tanners. Studies seeking to link indoor tanning to education level and income have returned inconsistent results. Prevalence was highest in one German study among those with a moderate level of education (neither high nor low).
The late teens to early–mid 20s is the highest-prevalence age group. In a national survey of white teenagers in 2003 in the US (aged 13–19), 24% had used a tanning facility. Indoor-tanning prevalence figures in the US vary from 30 million each year to just under 10 million (7.8 million women and 1.9 million men).
The figures in the US are in decline: according to the Centres for Disease Control and Prevention, usage in the 18–29 age group fell from 11.3 percent in 2010 to 8.6 percent in 2013, perhaps attributable in part to a 10% "tanning tax" introduced in 2010. Attitudes toward tanning vary across states; in one study, doctors in the northeast and midwest of the country were more likely than those in the south or west to recommend tanning beds to treat vitamin D deficiency and depression.
Tanning bed use is more prevalent in northern countries. In Sweden in 2001, 44% said they had used one (in a survey of 1,752 men and women aged 18–37). Their use increased in Denmark between 1994 and 2002 from 35% to 50% (reported use in the previous two years). In Germany, between 29% and 47% had used one, and one survey found that 21% had done so in the previous year. In France, 15% of adults in 1994–1995 had tanned indoors; the practice was more common in the north of France. In 2006, 12% of grade 9–10 students in Canada had used a tanning bed in the last year. In 2004, 7% of 8–11-year-olds in Scotland said they had used one. Tanning bed use is higher in the UK in the north of England. One study found that the prevalence was lower in London than in less urban areas of the country. | 5 | Photochemistry |
Hydrogels are created from crosslinked polymers that are water-insoluble. Polymer hydrogels absorb significant amounts of aqueous solutions, and therefore have a high water content. This high water content makes hydrogel more similar to living body tissues than any other material for tissue regeneration. Additionally, polymer scaffolds using self-healing hydrogels are structurally similar to the extracellular matrices of many of the tissues. Scaffolds act as three-dimensional artificial templates in which the tissue targeted for reconstruction is cultured to grow onto. The high porosity of hydrogels allows for the diffusion of cells during migration, as well as the transfer of nutrients and waste products away from cellular membranes. Scaffolds are subject to harsh processing conditions during tissue culturing. These include mechanical stimulation to promote cellular growth, a process which places stress on the scaffold structure. This stress may lead to localized rupturing of the scaffold which is detrimental to the reconstruction process. In a self-healing hydrogel scaffold, ruptured scaffolds have the ability for localized self-repair of their damaged three-dimensional structure.
Current research is exploring the effectiveness of using various types of hydrogel scaffolds for tissue engineering and regeneration including synthetic hydrogels, biological hydrogels, and biohybrid hydrogels.
In 2019, researchers Biplab Sarkar and Vivek Kumar of the New Jersey Institute of Technology developed a self-assembling peptide hydrogel that has proven successful in increasing blood vessel regrowth and neuron survival in rats affected by Traumatic Brain Injuries (TBI). By adapting the hydrogel to closely resemble brain tissue and injecting it into the injured areas of the brain, the researchers’ studies have shown improved mobility and cognition after only a week of treatment. If trials continued to prove successful, this peptide hydrogel may be approved for human trials and eventual widespread use in the medical community as a treatment for TBIs. This hydrogel also has the potential to be adapted to other forms of tissue in the human body, and promote regeneration and recovery from other injuries. | 7 | Physical Chemistry |
In organic chemistry, S-nitrosothiols, also known as thionitrites, are organic compounds or functional groups containing a nitroso group attached to the sulfur atom of a thiol. S-Nitrosothiols have the general formula , where R denotes an organic group. Originally suggested by Ignarro to serve as intermediates in the action of organic nitrates, endogenous S-nitrosothiols were discovered by Stamler and colleagues (S-nitrosoalbumin in plasma and S-nitrosoglutathione in airway lining fluid) and shown to represent a main source of NO bioactivity in vivo. More recently, S-nitrosothiols have been implicated as primary mediators of protein S-nitrosylation, the oxidative modification of cysteine thiol that provides ubiquitous regulation of protein function.
S-Nitrosothiols have received much attention in biochemistry because they serve as donors of both the nitrosonium ion and of nitric oxide and thus best rationalize the chemistry of NO-based signaling in living systems, especially related to vasodilation. Red blood cells, for instance, carry an essential reservoir of S-nitrosohemoglobin and release S-nitrosothiols into the bloodstream under low-oxygen conditions, causing the blood vessels to dilate.
S-nitrosothiols are composed of small molecules, peptides and proteins. The addition of a nitroso group to a sulfur atom of an amino acid residue of a protein is known as S-nitrosylation or S-nitrosation. This is a reversible process and a major form of posttranslational modification of proteins.
S-Nitrosylated proteins (SNO-proteins) serve to transmit nitric oxide (NO) bioactivity and to regulate protein function through enzymatic mechanisms analogous to phosphorylation and ubiquitinylation: SNO donors target specific amino acids motifs; post-translational modification leads to changes in protein activity, protein interactions, or subcellular location of target proteins; all major classes of proteins can undergo S-nitrosylation, which is mediated by enzymes that add (nitrosylases) and remove (denitrosylases) SNO from proteins, respectively. Accordingly, nitric oxide synthase (NOS) activity does not directly lead to SNO formation, but rather requires an additional class of enzymes (SNO synthases), which catalyze denovo S-nitrosylation. NOSs ultimately target specific Cys residues for S-nitrosylation through conjoint actions of SNO-synthases and transnitrosylases (transnitrosation reactions), which are involved in virtually all forms of cell signaling, ranging from regulation of ion channels and G-protein coupled reactions to receptor stimulation and activation of nuclear regulatory protein. | 0 | Organic Chemistry |
The Great Oxygenation Event (GOE) is characterized by the disappearance of sulfur isotope mass-independent fractionation (MIF) in the sedimentary records at around 2.45 billion years ago (Ga). The MIF of sulfur isotope (ΔS) is defined by the deviation of measured δS value from the δS value inferred from the measured δS value according to the mass dependent fractionation law. The Great Oxidation Event represented a massive transition of global sulfur cycles. Before the Great Oxidation Event, the sulfur cycle was heavily influenced by the ultraviolet (UV) radiation and the associated photochemical reactions, which induced the sulfur isotope mass-independent fractionation (ΔS ≠ 0). The preservation of sulfur isotope mass-independent fractionation signals requires the atmospheric O lower than 10 of present atmospheric level (PAL). The disappearance of sulfur isotope mass-independent fractionation at ~2.45 Ga indicates that atmospheric pO exceeded 10 present atmospheric level after the Great Oxygenation Event. Oxygen played an essential role in the global sulfur cycles after the Great Oxygenation Event, such as oxidative weathering of sulfides. The burial of pyrite in sediments in turn contributes to the accumulation of free O in Earth's surface environment. | 9 | Geochemistry |
In thermodynamics and thermal physics, the Gouy-Stodola theorem is an important theorem for the quantification of irreversibilities in an open system, and aids in the exergy analysis of thermodynamic processes. It asserts that the rate at which work is lost during a process, or at which exergy is destroyed, is proportional to the rate at which entropy is generated, and that the proportionality coefficient is the temperature of the ambient heat reservoir. In the literature, the theorem often appears in a slightly modified form, changing the proportionality coefficient.
The theorem is named jointly after the French physicist Georges Gouy and Slovak physicist Aurel Stodola, who demonstrated the theorem in 1889 and 1905 respectively. Gouy used it while working on exergy and utilisable energy, and Stodola while working on steam and gas engines. | 7 | Physical Chemistry |
TA cloning (also known as rapid cloning or T cloning) is a subcloning technique that avoids the use of restriction enzymes and is easier and quicker than traditional subcloning. The technique relies on the ability of adenine (A) and thymine (T) (complementary basepairs) on different DNA fragments to hybridize and, in the presence of ligase, become ligated together. PCR products are usually amplified using Taq DNA polymerase which preferentially adds an adenine to the 3 end of the product. Such PCR amplified inserts are cloned into linearized vectors that have complementary 3 thymine overhangs. | 1 | Biochemistry |
The research on transgender reproduction and family planning is limited. A 2020 comparative study of children born to a transgender father and cisgender mother via donor sperm insemination in France showed no significant differences to IVF and naturally conceived children of cisgender parents.
Transgender men can experience challenges in pregnancy and birthing from the cis-normative structure within the medical system, as well as psychological challenges such as renewed gender dysphoria. The effect of continued testosterone therapy during pregnancy and breastfeeding is undetermined. Ethical concerns include reproductive rights, reproductive justice, physician autonomy, and transphobia within the health care setting. | 1 | Biochemistry |
While the term pewter covers a range of tin-based alloys, the term English pewter has come to represent a strictly-controlled alloy, specified by BSEN611-1 and British Standard 5140, consisting mainly of tin (ideally 92%), with the balance made up of antimony and copper. Significantly, it is free of lead and nickel. Although the exact percentages vary between manufacturers, a typical standard for present-day pewter is approximately 91% tin, 7.5% antimony and 1.5% copper.
By the 15th century, the Worshipful Company of Pewterers controlled pewter constituents in England. This company originally had two grades of pewter, but in the 16th century a third grade was added. The first type, known as "fine metal", was used for tableware. It consisted of tin with as much copper as it could absorb, which is about 1%. The second type, known as "trifling metal" or "trifle", was used for holloware. It is made up of fine metal with approximately 4% lead. The last type of pewter, known as "lay" or "ley" metal, was used for items that were not in contact with food or drink. It consisted of tin with 15% lead. These three alloys were used, with little variation, until the 20th century.
Lead was removed from the composition in 1974, by BS5140, reinforced by the European directive BSEN611 in 1994.
Until the end of the 18th century, the only method of manufacture was by casting and the soldering of components. From the last quarter of the 18th century, improvement in alloys (e.g. britannia metal) and techniques allowed objects to be made from pewter by stamping and spinning. | 8 | Metallurgy |
In sizing, the strength and printability of paper is increased. Sizing also improves the hydrophilic character, liquid spreading, and affinity for ink. Starch is the most common sizing agent. Cationic starch and hydrophilic agents are also applied, including alkenyl succinic anhydride (ASA) and alkyl ketene dimers (AKD).
Cationic starch increases strength because it binds to the anionic paper fibers. The amount added is usually between ten and thirty pounds per ton. When starch exceeds the amount the fibers can bind to, it causes foaming in the production process as well as decreased retention and drainage. | 7 | Physical Chemistry |
In 1984 scientists Bouma, Radom and Yates originated the term through extensive experimental research but they were not the first to deal with distonic ions. Experiments date back to the 1970s with Gross and McLafferty who were the first to propose the idea of such a species. | 7 | Physical Chemistry |
Pyridine is used as a polar, basic, low-reactive solvent, for example in Knoevenagel condensations. It is especially suitable for the dehalogenation, where it acts as the base for the elimination reaction. In esterifications and acylations, pyridine activates the carboxylic acid chlorides and anhydrides. Even more active in these reactions are the derivatives 4-dimethylaminopyridine (DMAP) and 4-(1-pyrrolidinyl) pyridine. Pyridine is also used as a base in some condensation reactions. | 0 | Organic Chemistry |
Delivery of oral high-dose supplements remains the principal strategy for minimizing deficiency. As of 2017, more than 80 countries worldwide are implementing universal VAS programs targeted to children 6–59 months of age through semi-annual national campaigns. Doses in these programs are one dose of 50,000 or 100,000 IU for children aged 6 to 11 months and 100,000 to 200,000 IU for children aged 12 months to five years, every four to six months. | 1 | Biochemistry |
In veterinary medicine, selegiline is sold under the brand name Anipryl (manufactured by Zoetis). It is used in dogs to treat canine cognitive dysfunction and, at higher doses, pituitary-dependent hyperadrenocorticism (PDH). Canine cognitive dysfunction is a form of dementia that mimics Alzheimer's disease in humans. Geriatric dogs treated with selegiline show improvements in sleeping pattern, reduced incontinence, and increased activity level; most show improvements by one month. Though it is labeled for dog use only, selegiline has been used off-label for geriatric cats with cognitive dysfunction.
Selegiline's efficacy in treating pituitary-dependent hyperadrenocorticism has been disputed. Theoretically, it works by increasing dopamine levels, which downregulates the release of ACTH, eventually leading to reduced levels of cortisol. Some claim that selegiline is only effective at treating PDH caused by lesions in the anterior pituitary (which comprise most canine cases). The greatest sign of improvement is lessening of abdominal distention.
Side effects in dogs are uncommon, but they include vomiting, diarrhea, diminished hearing, salivation, decreased weight and behavioral changes such as hyperactivity, listlessness, disorientation, and repetitive motions.
Selegiline does not appear to have a clinical effect on horses. | 4 | Stereochemistry |
Isotopic data from various locations within the Mid-Atlantic Ridge indicates the presence of mafic-to-felsic intrusive igneous rocks, including gabbro, diorite, and plagiogranite. These rocks showed high-grade metamorphism because of the presence of magmatic water, exceeding 600 °C. This deformation depleted host rocks of O, leading to further analysis of the ratio of O to O (δO).
Water in equilibrium with igneous melts should bear the same isotopic signature for O and δH. However, isotopic studies of magmatic water have demonstrated similarities to meteoric water, indicating circulation of magmatic and meteoric groundwater systems.
Isotopic analyses of fluid inclusions indicate a wide range of δO and δH content. Studies within these environments have shown an abundance of O and depletion in H relative to SMOW and meteoric waters. Within ore deposits, fluid inclusion data showed that the presence of δO vs δH are within the expected range. | 9 | Geochemistry |
It can be shown that the radial distribution function is related to the two-particle potential of mean force by:
In the dilute limit, the potential of mean force is the exact pair potential under which the equilibrium point configuration has a given . | 7 | Physical Chemistry |
Many nuclear-derived transcription factors have played a role in respiratory chain expression. These factors may have also contributed to the regulation of mitochondrial functions. Nuclear respiratory factor (NRF-1) fuses to respiratory encoding genes proteins, to the rate-limiting enzyme in biosynthesis, and to elements of replication and transcription of mitochondrial DNA, or mtDNA. The second nuclear respiratory factor (NRF-2) is necessary for the production of cytochrome c oxidase subunit IV (COXIV) and Vb (COXVb) to be maximized.
The studying of gene sequences for the purpose of speciation and determining genetic similarity is just one of the many uses of modern day genetics, and the role that both types of genes have in that process is important. Though both nuclear genes and those within endosymbiotic organelles provide the genetic makeup of an organism, there are distinct features that can be better observed when looking at one compared to the other. Mitochondrial DNA is useful in the study of speciation as it tends to be the first to evolve in the development of a new species, which is different from nuclear genes' chromosomes that can be examined and analyzed individually, each giving its own potential answer as to the speciation of a relatively recently evolved organism.
Low-copy nuclear genes in plants are valuable for improving phylogenetic reconstructions, especially when universal markers like Chloroplast DNA, or cpDNA and Nuclear ribosomal DNA, or nrDNA fall short. Challenges in using these genes include limited universal markers and the complexity of gene families. Nonetheless, they are essential for resolving close species relationships and understanding plant phylogenetic studies. While using low-copy nuclear genes requires additional lab work, advances in sequencing and cloning techniques have made it more accessible. Fast-evolving introns in these genes can offer crucial phylogenetic insights near species boundaries. This approach, along with the analysis of developmentally important genes, enhances the study of plant diversity and evolution.
As nuclear genes are the genetic basis of all eukaryotic organisms, anything that can affect their expression therefore directly affects characteristics about that organism on a cellular level. The interactions between the genes of endosymbiotic organelles like mitochondria and chloroplasts are just a few of the many factors that can act on the nuclear genome. | 1 | Biochemistry |
It is a flavoring ingredient and achieved a generally recognized as safe (GRAS) status in 1995 by the Flavor and Extract Manufacturers Association (FEMA). 2-Furoic acid has a distinct odor described as sweet, oily, herbaceous, and earthy.
2-Furoic acid helps sterilize and pasteurize many foods. It forms in situ from 2-furfural. 2-Furoic acid is also formed during coffee roasting, with up to 205 mg/kg. | 0 | Organic Chemistry |
Glycosidic bonds of the form discussed above are known as O-glycosidic bonds, in reference to the glycosidic oxygen that links the glycoside to the aglycone or reducing end sugar. In analogy, one also considers S-glycosidic bonds (which form thioglycosides), where the oxygen of the glycosidic bond is replaced with a sulfur atom. In the same way, N-glycosidic bonds, have the glycosidic bond oxygen replaced with nitrogen. Substances containing N-glycosidic bonds are also known as glycosylamines. C-glycosyl bonds have the glycosidic oxygen replaced by a carbon; the term "C-glycoside" is considered a misnomer by IUPAC and is discouraged. All of these modified glycosidic bonds have different susceptibility to hydrolysis, and in the case of C-glycosyl structures, they are typically more resistant to hydrolysis. | 0 | Organic Chemistry |
An example of aluminum alloys where solid solution strengthening happens by adding magnesium and manganese into the aluminum matrix. Commercially Mn can be added to the AA3xxx series and Mg can be added to the AA5xxx series. Mn addition to the Aluminum alloys assists in the recrystallization and recovery of the alloy which influences the grain size as well. Both of these systems are used in low to medium-strength applications, with appreciable formability and corrosion resistance. | 8 | Metallurgy |
Many forms of muscular dystrophy are associated with disorders of the dystrophin-associated protein complex.
Muscular dystrophy, the result of mutations in the genes that encode for dystrophin and the associated proteins that binds to it can arise in various forms. The most common form is known as Duchenne muscular dystrophy (DMD). DMD is usually discovered in early childhood and is most often seen occurring in males. There are several associated symptoms that can be observed in such patients including but not limited to a delay in walking and sitting, difficulty in breathing and heart failure. These symptoms are found as a result of the inability to synthesize dystrophin and associate protein complexes that leave muscles weak and unable to repair any damaged sustained. These perpetually weak muscles prohibit normal physical activity. | 1 | Biochemistry |
*1994 — Tanner Award for Teaching Excellence
*1995 — NSF Special Creativity Award in Organophosphorus Chemistry
*1998 — ACS Award for Encouraging Disadvantaged Students into Careers in the Chemical Sciences
*Chancellor's Award for Excellence in Undergraduate Education
*Howard University Outstanding Achievement Award | 4 | Stereochemistry |
MIRO Analytical is a Swiss manufacturer of laser-based gas analyzers and isotope analyzers.
The company is based in Zurich, Switzerland and was founded 2018. | 7 | Physical Chemistry |
Most insight in the problem probably emerges when approaching the effect form Landau Theory. Which is a little bit problematic as the melting of a bulk in general has to be considered as a first order phase transition, meaning the order parameter jumps at . The derivation of Lipowski (basic geometry shown in fig.2) leads to the following results when :
Where is the order parameter at the border between (2) and (l), the so-called extrapolation length and a constant that enters the model and has to be determined using experiment and other models. Hence one can see that the order parameter in the liquid film can undergo a continuous phase transition for large enough extrapolation length. A further result is that what corresponds to the result of the thermodynamical model in the case of short range interactions.
Landau Theory does not consider fluctuations like capillary waves, this could change the results qualitatively. | 7 | Physical Chemistry |
The wetlands that surround the lake spread over an area of 0.63 km, and are enclosed into an ancient shoreline. The origin of this larger open water lake remains unclear. If the lake level has remained stable, then the reduction in lake size is solely due to the conversion of these open waters into wetlands. Alternatively, lake shrinking might reflect a slight lowering of the average lake level, possibly due to a more efficient drainage at the lake outlet. In any case, it cannot be excluded that the lake level reverts in the future to its ancient stand, flooding areas that have now been filled and urbanized. Besides, the outlet drains to a cave that might get partially of completely obstructed by debris following large storms. Water ponding upstream of the cave could result in an increase in the lake level of 4,0 ± 0,3 m before surface overflow is achieved near the cave. | 2 | Environmental Chemistry |
Vanillin is an organic compound with the molecular formula . It is a phenolic aldehyde. Its functional groups include aldehyde, hydroxyl, and ether. It is the primary component of the extract of the vanilla bean. Synthetic vanillin is now used more often than natural vanilla extract as a flavoring in foods, beverages, and pharmaceuticals.
Vanillin and ethylvanillin are used by the food industry; ethylvanillin is more expensive, but has a stronger note. It differs from vanillin by having an ethoxy group (−O−CHCH) instead of a methoxy group (−O−CH).
Natural vanilla extract is a mixture of several hundred different compounds in addition to vanillin. Artificial vanilla flavoring is often a solution of pure vanillin, usually of synthetic origin. Because of the scarcity and expense of natural vanilla extract, synthetic preparation of its predominant component has long been of interest. The first commercial synthesis of vanillin began with the more readily available natural compound eugenol (4-allyl-2-methoxyphenol). Today, artificial vanillin is made either from guaiacol or lignin.
Lignin-based artificial vanilla flavoring is alleged to have a richer flavor profile than that from guiacol-based artificial vanilla; the difference is due to the presence of acetovanillone, a minor component in the lignin-derived product that is not found in vanillin synthesized from guaiacol. | 0 | Organic Chemistry |
By mass, iron is the most common element on Earth, and it is the fourth most abundant element in the Earth's crust. Thus, iron is widespread throughout the geosphere, and is also common on other planetary bodies. Natural variations in the iron in the geosphere are relatively small. Currently, the values of δFe measured in rocks and minerals range from -2.5‰ to +1.5‰. Iron isotope composition is homogeneous in igneous rocks to ±0.05‰, indicating that much of the geologic isotopic variability is a result of the formation of rocks and minerals at low temperature. This homogeneity is particularly useful when tracing processes which result in fractionation through the system. While fractionation of igneous rocks is relatively constant, there are larger variations in the iron isotopic composition of chemical sediments. Thus, iron isotopes are used to determine the origin of the protolith of heavily metamorphosed rocks of a sedimentary origin. Improvements of the understanding regarding the way in which iron isotopes fractionate in the geosphere can help to better understand geologic processes of formation. | 9 | Geochemistry |
The sulfide ion, S, does not exist in aqueous alkaline solutions of NaS. Instead sulfide converts to hydrosulfide:
:S + HO → SH + OH
Upon treatment with an acid, sulfide salts convert to hydrogen sulfide:
:S + H → SH
:SH + H → HS
Oxidation of sulfide is a complicated process. Depending on the conditions, the oxidation can produce elemental sulfur, polysulfides, polythionates, sulfite, or sulfate. Metal sulfides react with halogens, forming sulfur and metal salts.
:8 MgS + 8 I → S + 8 MgI | 0 | Organic Chemistry |
Most radiometers for remote sensing (RS) acquire multispectral images. Dividing the spectrum into many bands, multispectral is the opposite of panchromatic, which records only the total intensity of radiation falling on each pixel. Usually, Earth observation satellites have three or more radiometers. Each acquires one digital image (in remote sensing, called a scene) in a small spectral band. The bands are grouped into wavelength regions based on the origin of the light and the interests of the researchers. | 7 | Physical Chemistry |
In the end of Feynmans paper, he states that, "Van der Waals forces can also be interpreted as arising from charge distributions with higher concentration between the nuclei. The Schrödinger perturbation theory for two interacting atoms at a separation , large compared to the radii of the atoms, leads to the result that the charge distribution of each is distorted from central symmetry, a dipole moment of order being induced in each atom. The negative charge distribution of each atom has its center of gravity moved slightly toward the other. It is not the interaction of these dipoles which leads to van der Waalss force, but rather the attraction of each nucleus for the distorted charge distribution of its own' electrons that gives the attractive force." | 6 | Supramolecular Chemistry |
Traditionally bun ingots were seen as a primary product of smelting, forming at the base of a furnace beneath a layer of less dense slag. However, experimental reconstruction of copper smelting showed that regular plano-convex ingots are difficult to form within the smelting furnace, producing only small ingots or copper prills that need to be remelted. High purity copper bun ingots found in Late Bronze Age Britain and the Mediterranean seem to have undergone a secondary refining procedure.
The metallographic structure and high iron compositions of some plano-convex ingots suggest that they are the product of primary smelting. Tylecote suggested that Roman plano-convex copper ingots may have been formed by tapping both slag and copper in one step into a mould or pit outside the furnace. A similar process was described by Agricola in book IX of his De Re Metallica and has been replicated experimentally. | 8 | Metallurgy |
As for technical competence, the following topics are especially important:
* sampling
* traceability of measurement result
* validation of measurement procedure
* measurement uncertainty
* participation in interlaboratory comparisons
* internal quality control.
As it is important to have globally harmonised approach to the above-mentioned topics, various training and teaching material have been developed at the European level, as to support implementation e.g. by EURACHEM and by TrainMiC. | 3 | Analytical Chemistry |
Beilstein was founded as German-language standard reference work for organic chemistry was intended to supplement the content of the Chemisches Zentralblatt. In light of the leading role of German chemistry in international science, Beilstein's handbook quickly became renowned as a standard reference throughout the world. The first edition of his "Handbuch der organischen Chemie" appeared in two volumes in 1881 and 1883, referencing 15,000 compounds in about 2,200 pages. The second edition appeared in three volumes from 1885 to 1889 and 4,080 pages, and from 1892 to 1899 came the third edition in 4 volumes and 6,844 pages. In 1896, the continuation of the handbook was placed in the care of the German Chemical Society, which first published the supplementary volumes of the 3rd edition and, from 1918, the fourth edition. Starting with the 5th supplement, following the superseding of German by English as most relevant scientific language, the handbook appeared in English. | 0 | Organic Chemistry |
Once excited, atoms will lose their energy fairly quickly. Of the various ways that this energy can be lost, the most important is radiatively, meaning that a photon is released to carry the energy away. In optical atomic spectroscopy, the wavelength of this photon can be used to determine the identity of the atom (that is, which chemical element it is) and the number of photons is directly proportional to the concentration of that element in the sample. Some collisions (those of high enough energy) will cause ionization. In atomic mass spectrometry, these ions are detected. Their mass identifies the type of atoms and their quantity reveals the amount of that element in the sample. | 3 | Analytical Chemistry |
The crystallographic point group or crystal class is the mathematical group comprising the symmetry operations that leave at least one point unmoved and that leave the appearance of the crystal structure unchanged. These symmetry operations include
*Reflection, which reflects the structure across a reflection plane
*Rotation, which rotates the structure a specified portion of a circle about a rotation axis
*Inversion, which changes the sign of the coordinate of each point with respect to a center of symmetry or inversion point
*Improper rotation, which consists of a rotation about an axis followed by an inversion.
Rotation axes (proper and improper), reflection planes, and centers of symmetry are collectively called symmetry elements. There are 32 possible crystal classes. Each one can be classified into one of the seven crystal systems. | 3 | Analytical Chemistry |
The role of endoglin plays in angiogenesis and the modulation of TGF beta receptor signaling, which mediates cellular localization, cellular migration, cellular morphology, cell proliferation, cluster formation, etc., makes endoglin an important player in tumor growth and metastasis. Being able to target and efficiently reduce or halt neoangiogenesis in tumors would prevent metastasis of primary cancer cells into other areas of the body. Also, it has been suggested that endoglin can be used for tumor imaging and prognosis.
The role of endoglin in cancer can be contradicting at times since it is needed for neoangiogenesis in tumors, which is needed for tumor growth and survival, yet the reduction in expression of endoglin has in many cancers correlated with a negative outcome of that cancer. In breast cancer, for example, the reduction of the full form of endoglin, and the increase of the soluble form of endoglin correlate with metastasis of cancer cells. The TGF beta receptor-endoglin complex relay contradicting signals from TGF beta as well. TGF beta can act as a tumor suppressor in the premalignant stage of the benign neoplasm by inhibiting its growth and inducing apoptosis. However, once the cancer cells have gone through the Hallmarks of Cancer and lost inhibitory growth responses, TGF beta mediates cell invasion, angiogenesis (with the help of endoglin), immune system evasion, and their ECM composition, allowing them to become malignant. | 1 | Biochemistry |
A variant of the 3-hydroxypropionate cycle was found to operate in the aerobic extreme thermoacidophile archaeon Metallosphaera sedula. This pathway is called the 3-hydroxypropionate/4-hydroxybutyrate cycle.
Yet another variant of the 3-hydroxypropionate cycle is the dicarboxylate/4-hydroxybutyrate cycle. It was discovered in anaerobic archaea.
It was proposed in 2008 for the hyperthermophile archeon Ignicoccus hospitalis. | 5 | Photochemistry |
Plane-wave topography can be made to extract an additional wealth of information from a sample by recording not just one image, but an entire sequence of topographs all along the sample's rocking curve. By following the diffracted intensity in one pixel across the entire sequence of images, local rocking curves from very small areas of sample surface can be reconstructed.
Although the required post-processing and numerical analysis is sometimes moderately demanding, the effort is often compensated by very comprehensive information on the sample's local properties. Quantities that become quantitatively measurable in this way include local scattering power, local lattice tilts (crystallite misorientation), and local lattice quality and perfection. Spatial resolution is, in many cases, essentially given by the detector pixel size.
The technique of sequential topography, in combination with appropriate data analysis methods also called rocking curve imaging, constitutes a method of microdiffraction imaging, i.e. a combination of X-ray imaging with X-ray diffractometry.
Literature: | 3 | Analytical Chemistry |
In 2021, calcium was the 243rd most commonly prescribed medication in the United States, with more than 1million prescriptions. | 1 | Biochemistry |
Solid is one of the four fundamental states of matter along with liquid, gas, and plasma. The molecules in a solid are closely packed together and contain the least amount of kinetic energy. A solid is characterized by structural rigidity (as in rigid bodies) and resistance to a force applied to the surface. Unlike a liquid, a solid object does not flow to take on the shape of its container, nor does it expand to fill the entire available volume like a gas. The atoms in a solid are bound to each other, either in a regular geometric lattice (crystalline solids, which include metals and ordinary ice), or irregularly (an amorphous solid such as common window glass). Solids cannot be compressed with little pressure whereas gases can be compressed with little pressure because the molecules in a gas are loosely packed.
The branch of physics that deals with solids is called solid-state physics, and is the main branch of condensed matter physics (which also includes liquids). Materials science is primarily concerned with the physical and chemical properties of solids. Solid-state chemistry is especially concerned with the synthesis of novel materials, as well as the science of identification and chemical composition. | 7 | Physical Chemistry |
Desmodium also controls the parasitic weed, Striga, resulting in significant yield increases of about 2 tonnes/hectare (0.9 short tons per acre) per cropping season. In addition to benefits derived from increased nitrogen availability and competition for light, it was found that D. uncinatum strongly suppresses striga growth through allelopathy. These effects are thought to be related to isoflavanones produced in Desmodium roots, which can either promote the germination of striga seeds or inhibit seedling growth, depending on their structure. Together, these effects result in the phenomenon known as "suicidal germination", thus reducing the striga seed bank in the soil. Other Desmodium species have also been evaluated and have similar effects on stemborers and striga weed and are currently being used as intercrops in maize, sorghum and millets. | 1 | Biochemistry |
At one time, stable carbenes were thought to reversibly dimerise through the so-called Wanzlick equilibrium. However, imidazol-2-ylidenes and triazol-5-ylidenes are thermodynamically stable and do not dimerise, and have been stored in solution in the absence of water and air for years. This is presumably due to the aromatic nature of these carbenes, which is lost upon dimerisation. In fact imidazol-2-ylidenes are so thermodynamically stable that only in highly constrained conditions are these carbenes forced to dimerise.
Chen and Taton made a doubly tethered diimidazol-2-ylidene by deprotonating the respective diimidazolium salt. Only the deprotonation of the doubly tethered diimidazolium salt with the shorter methylene bridge (–CH–) resulted in the dicarbene dimer:
If this dimer existed as a dicarbene, the electron lone pairs on the carbenic carbon would be forced into close proximity. Presumably the resulting repulsive electrostatic interactions would have a significant destabilising effect. To avoid this electronic interaction, the carbene units dimerise.
On the other hand, heteroamino carbenes (such as RN–C–OR or RN–C–SR) and non-aromatic carbenes such as diaminocarbenes (such as RN–C–NR) have been shown to dimerise, albeit quite slowly. This has been presumed to be due to the high barrier to singlet state dimerisation:
Diaminocarbenes do not truly dimerise, but rather form the dimer by reaction via formamidinium salts, a protonated precursor species. Accordingly, this reaction can be acid catalysed. This reaction occurs because unlike imidazolium based carbenes, there is no loss of aromaticity in protonation of the carbene.
Unlike the dimerisation of triplet state carbenes, these singlet state carbenes do not approach head to head ("least motion"), but rather the carbene lone pair attacks the empty carbon p-orbital ("non-least motion"). Carbene dimerisation can be catalyzed by both acids and metals. | 0 | Organic Chemistry |
Gel permeation chromatography is conducted almost exclusively in chromatography systems. The experimental design is not much different from other techniques of High Performance liquid chromatography. Samples are dissolved in an appropriate solvent, in the case of GPC these tend to be organic solvents and after filtering the solution it is injected onto a column. The separation of multi-component mixture takes place in the column. The constant supply of fresh eluent to the column is accomplished by the use of a pump. Since most analytes are not visible to the naked eye a detector is needed. Often multiple detectors are used to gain additional information about the polymer sample. The availability of a detector makes the fractionation convenient and accurate. | 3 | Analytical Chemistry |
Attempts to find anesthetics with less metabolism led to halogenated ethers such as enflurane and isoflurane. The incidence of hepatic reactions with these agents is lower. The exact degree of hepatotoxic potential of enflurane is debated, although it is minimally metabolized. Isoflurane is essentially not metabolized and reports of associated liver injury are quite rare. Small amounts of trifluoroacetic acid can be formed from both halothane and isoflurane metabolism and possibly accounts for cross sensitization of patients between these agents.
The main advantage of the more modern agents is lower blood solubility, resulting in faster induction of and recovery from anaesthesia. | 4 | Stereochemistry |
By metal vapor synthesis, metal atoms co-condensed with arenes react to give complexes of the type M(arene). Cr(CH) can be produced by this method.
Cr(CO) reacts directly with benzene and other arenes to give the piano stool complexes Cr(CR)(CO). The carbonyls of Mo and W behave comparably. The method works particularly well with electron-rich arenes (e.g., anisole, mesitylene). The reaction has been extended to the synthesis of [Mn(CR)(CO)]:
:BrMn(CO) + Ag + CR → [Mn(CR)(CO)] + AgBr + 2 CO | 0 | Organic Chemistry |
Corrosion in space has the highest impact on spacecraft with moving parts. Early satellites tended to develop problems with seizing bearings. Now the bearings are coated with a thin layer of gold.
Different materials resist corrosion in space differently. For example, aluminium is slowly eroded by atomic oxygen, while gold and platinum are highly corrosion-resistant. Gold-coated foils and thin layers of gold on exposed surfaces are therefore used to protect the spacecraft from the harsh environment. Thin layers of silicon dioxide deposited on the surfaces can also protect metals from the effects of atomic oxygen; e.g., the Starshine 3 satellite aluminium front mirrors were protected that way. However, the protective layers are subject to erosion by micrometeorites.
Silver builds up a layer of silver oxide, which tends to flake off and has no protective function; such gradual erosion of silver interconnects of solar cells was found to be the cause of some observed in-orbit failures.
Many plastics are considerably sensitive to atomic oxygen and ionizing radiation. Coatings resistant to atomic oxygen are a common protection method, especially for plastics. Silicone-based paints and coatings are frequently employed, due to their excellent resistance to radiation and atomic oxygen. However, the silicone durability is somewhat limited, as the surface exposed to atomic oxygen is converted to silica which is brittle and tends to crack. | 8 | Metallurgy |
Salahuddin was born on 7 July 1937 in Jairajpur, Azamgarh, Uttar Pradesh. His father, Fazlul Bari, was a teacher at the Shibli National College, Azamgarh where he received his early education, and he later completed his undergraduate and master's degrees in 1955 and 1957 in chemistry from the Aligarh Muslim University. Initially as a research student, he took interest in physical chemistry, obtaining his PhD degree in chemistry from Aligarh Muslim University Aligarh (1962). | 1 | Biochemistry |
Thomas Shirley Hele, OBE, MD, FRCP (b Carlisle 24 October 1881 – d Cambridge 23 January 1953) was an academic in the 20th century.
Hele was educated at Carlisle Grammar School ; Sedbergh School; Emmanuel College, Cambridge (Fellow, 1911); and Barts. He was University Lecturer in Biochemistry from 1921; Tutor at Emmanuel from 1922 to 1935; its Master from 1935 to 1951; and Vice-Chancellor of the University of Cambridge from 1943 to 1945. | 1 | Biochemistry |
Energy returned on energy invested (EROEI) is the ratio of energy delivered by an energy technology to the energy invested to set up the technology. | 7 | Physical Chemistry |
Lipotoxicity in cardiac tissue is attributed to excess saturated fatty acids. The apoptosis that follows is believed to be caused by unfolded protein response in the endoplasmic reticulum. Researchers are working on treatments that will increase the oxidation of these fatty acids within the heart in order to prevent the lipotoxic effects. | 1 | Biochemistry |
The discipline of heat transfer, typically considered an aspect of mechanical engineering and chemical engineering, deals with specific applied methods by which thermal energy in a system is generated, or converted, or transferred to another system. Although the definition of heat implicitly means the transfer of energy, the term heat transfer encompasses this traditional usage in many engineering disciplines and laymen language.
Heat transfer is generally described as including the mechanisms of heat conduction, heat convection, thermal radiation, but may include mass transfer and heat in processes of phase changes.
Convection may be described as the combined effects of conduction and fluid flow. From the thermodynamic point of view, heat flows into a fluid by diffusion to increase its energy, the fluid then transfers (advects) this increased internal energy (not heat) from one location to another, and this is then followed by a second thermal interaction which transfers heat to a second body or system, again by diffusion. This entire process is often regarded as an additional mechanism of heat transfer, although technically, "heat transfer" and thus heating and cooling occurs only on either end of such a conductive flow, but not as a result of flow. Thus, conduction can be said to "transfer" heat only as a net result of the process, but may not do so at every time within the complicated convective process. | 7 | Physical Chemistry |
This technique measures a concentration change of proteins in bulk solution before and after adsorption, Δc. Any protein concentration change is attributed to the adsorbed layer, Γ.
Γ = Δc V/A
where:
*V = total volume of protein solution
*A = Total area available for adsorption
This method also requires a high surface area material such as particulate and beaded adsorbents. | 1 | Biochemistry |
Durrant was appointed Commander of the Order of the British Empire (CBE) in the 2022 Birthday Honours for services to photochemistry and solar energy research.
*2018: Awarded Hughes Medal by the Royal Society
*2017: Elected a Fellow of the Royal Society (FRS) for his research contributions in photochemistry of new materials for use in solar energy conversion – specifically targeting both solar cells in photovoltaic systems and solar to fuel in artificial photosynthesis.
*2016: Elected a Fellow of the Learned Society of Wales
*2016: Awarded president's award for excellence in research supervision.
*2012: Awarded the Tilden Prize by the Royal Society of Chemistry
*2009: Awarded the Environment Prize by the Royal Society of Chemistry
*1994: Awarded the Meldola Medal and Prize by the Royal Society of Chemistry | 5 | Photochemistry |
The relative amount of fading can be measured and studied by using standard test strips. In the workflow of the Blue Wool test, one reference strip set shall be stored protected from any exposure to light. Simultaneously, another equivalent test strip set is exposed under a light source defined in the standard. For example, if the lightfastness of the colourant is indicated to be 5 on the Blue Wool scale, it can be expected to fade by a similar amount as the strip number 5 in the Blue Wool test strip set. The success of the test can be confirmed by comparing the test strip set with the reference set that was stored protected from the light. | 5 | Photochemistry |
Polymer degradation by galvanic action was first described in the technical literature in 1990 by Michael C. Faudree, an employee at General Dynamics, Fort Worth Division. The phenomenon has been referred to as the "Faudree Effect", and can possibly be used as a sustainable process to degrade non-recyclable thermoset plastics, and also has had implications for preventing corrosion on aircraft for safety such as changes in design. When carbon-fiber-reinforced polymer is attached to a metal surface, the carbon fiber can act as a cathode if exposed to water or sufficient humidity, resulting in galvanic corrosion. This has been seen in engineering when carbon-fiber polymers have been used to reinforce weakened steel structures. Reactions have also been seen in aluminium and magnesium alloys, polymers affected include bismaleimides (BMI), and polyimides. The mechanism of degradation is believed to involve the electrochemical generation of hydroxide ions, which then cleave the amide bonds. | 7 | Physical Chemistry |
Physcomitrella plants were engineered with multiple knockouts to prevent the plant-specific glycosylation of proteins, an important post-translational modification. These knockout mosses are used to produce complex biopharmaceuticals in the field of molecular farming. | 1 | Biochemistry |
The Simon–Glatzel equation is an empirical correlation describing the pressure dependence of the melting temperature of a solid. The pressure dependence of the melting temperature is small for small pressure changes because the volume change during fusion or melting is rather small. However, at very high pressures higher melting temperatures are generally observed as the liquid usually occupies a larger volume than the solid making melting more thermodynamically unfavorable at elevated pressure. If the liquid has a smaller volume than the solid (as for ice and liquid water) a higher pressure leads to a lower melting point. | 7 | Physical Chemistry |
The related sulfinamides (R(S=O)NHR) are amides of sulfinic acids (R(S=O)OH) (see sulfinyl). Chiral sulfinamides such as tert-butanesulfinamide, p-toluenesulfinamide and 2,4,6-trimethylbenzenesulfinamide are relevant to asymmetric synthesis. | 0 | Organic Chemistry |
The act of recycling plastic degrades its polymer chains, usually as a result of thermal damage similar to that seen during initial processing. In some cases, this is turned into an advantage by intentionally and completely depolymerising the plastic back into its starting monomers, which can then be used to generate fresh, un-degraded plastic. In theory, this chemical (or feedstock) recycling offers infinite recyclability, but it is also more expensive and can have a higher carbon footprint because of its energy costs. Mechanical recycling, where the plastic is simply remelted and reformed, is more common, although this usually results in a lower-quality product. Alternatively, plastic may simply be burnt as a fuel in a waste-to-energy process. | 7 | Physical Chemistry |
In a typical spectrum analyzer there are options to set the start, stop, and center frequency. The frequency halfway between the stop and start frequencies on a spectrum analyzer display is known as the center frequency. This is the frequency that is in the middle of the display's frequency axis. Span specifies the range between the start and stop frequencies. These two parameters allow for adjustment of the display within the frequency range of the instrument to enhance visibility of the spectrum measured. | 7 | Physical Chemistry |
Relative rates of chemical reactions provide useful insights into the effects of the steric bulk of substituents. Under standard conditions, methyl bromide solvolyzes 10 faster than does neopentyl bromide. The difference reflects the inhibition of attack on the compound with the sterically bulky (CH)C group. | 4 | Stereochemistry |
Metal ions are essential to the function of many proteins present in living organisms, such as metalloproteins and enzymes that require metal ions as cofactors. Processes including oxygen transport and DNA replication are carried out using enzymes such as DNA polymerase, which in humans requires magnesium and zinc to function properly. Other biomolecules also contain metal ions in their structure, such as iodine in human thyroid hormones.
The uses of some of them are listed below. The list is not exhaustive, because it covers only the principal class members; others that are trace metals of especially low bioconcentration are not explored herein. Some elements that are nonmetals or metalloids (such as selenium) are beyond the scope of this article. | 1 | Biochemistry |
Another way of deriving the Gibbs-Duhem equation can be found by taking the extensivity of energy into account. Extensivity implies that
where denotes all extensive variables of the internal energy . The internal energy is thus a first-order homogenous function. Applying Euler's homogeneous function theorem, one finds the following relation when taking only volume, number of particles, and entropy as extensive variables:
Taking the total differential, one finds
Finally, one can equate this expression to the definition of to find the Gibbs-Duhem equation | 7 | Physical Chemistry |
The electron gun is one of the most important piece of equipment in a RHEED system. The gun limits the resolution and testing limits of the system. Tungsten filaments are the primary electron source for the electron gun of most RHEED systems due to the low work function of tungsten. In the typical setup, the tungsten filament is the cathode and a positively biased anode draws electrons from the tip of the tungsten filament.
The magnitude of the anode bias determines the energy of the incident electrons. The optimal anode bias is dependent upon the type of information desired. At large incident angles, electrons with high energy can penetrate the surface of the sample and degrade the surface sensitivity of the instrument. However, the dimensions of the Laue zones are proportional to the inverse square of the electron energy meaning that more information is recorded at the detector at higher incident electron energies. For general surface characterization, the electron gun is operated the range of 10-30 keV.
In a typical RHEED setup, one magnetic and one electric field focus the incident beam of electrons. A negatively biased Wehnelt electrode positioned between the cathode filament and anode applies a small electric field, which focuses the electrons as they pass through the anode. An adjustable magnetic lens focuses the electrons onto the sample surface after they pass through the anode. A typical RHEED source has a focal length around 50 cm. The beam is focused to the smallest possible point at the detector rather than the sample surface so that the diffraction pattern has the best resolution.
Phosphor screens that exhibit photoluminescence are widely used as detectors. These detectors emit green light from areas where electrons hit their surface and are common to TEM as well. The detector screen is useful for aligning the pattern to an optimal position and intensity. CCD cameras capture the patterns to allow for digital analysis. | 3 | Analytical Chemistry |
*2015 Friedrich Wilhelm Bessel Award, granted by the Alexander Von Humboldt Foundation
*2013 William H. Kiekhofer Distinguished Teaching Award, presented by University of Wisconsin-Madison
*2010 Eli Lilly Grantee Award, conferred by Eli Lilly & Company
*2010 Camille Dreyfus Teacher-Scholar Award, granted by the Camille & Henry Dreyfus Foundation
*2009 Amgen Young Investigator Award, sponsored by Amgen
*2009 Alfred P. Sloan Research Fellowship, awarded by the Alfred P. Sloan Foundation
*2008 Cottrell Scholar Award, presented by Research Corporation for Scientific Advancement (RCSA)
*2008 Beckman Young Investigator Award, granted by the Arnold and Mabel Beckman Foundation
*2007 NSF CAREER Award, initiated through the National Science Foundation CAREER Awards | 0 | Organic Chemistry |
Bases: adenine (A), cytosine (C), guanine (G) and thymine (T) or uracil (U).
Amino acids: Alanine (Ala, A), Arginine (Arg, R), Asparagine (Asn, N), Aspartic acid (Asp, D), Cysteine (Cys, C), Glutamic acid (Glu, E), Glutamine (Gln, Q), Glycine (Gly, G), Histidine (His, H), Isoleucine (Ile, I), Leucine (Leu, L), Lysine (Lys, K), Methionine (Met, M), Phenylalanine (Phe, F), Proline (Pro, P), Serine (Ser, S), Threonine (Thr, T), Tryptophan (Trp, W), Tyrosine (Tyr, Y), Valine (Val, V) | 1 | Biochemistry |
JSS is a peer-reviewed journal covering fundamental and applied areas of solid-state science and technology, including experimental and theoretical aspects of the chemistry and physics of materials and devices. | 7 | Physical Chemistry |
* 2005 IEEE Donald G. Fink Prize Paper Award
* 2008 Eurosensors Fellow
* 2011 DECHEMA Award of the Max Buchner Research Foundation | 7 | Physical Chemistry |
tert-Butyllithium is produced commercially by treating tert-butyl chloride with lithium metal. Its synthesis was first reported by R. B. Woodward in 1941. | 0 | Organic Chemistry |
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