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Brevianamide Brevianamides are indole alkaloids that belong to a class of naturally occurring 2,5-diketopiperazines produced as secondary metabolites of fungi in the genus "Penicillium" and "Aspergillus". Structurally similar to paraherquamides, they are a small class compounds that contain a bicyclo[2.2.2]diazoctane ring system. One of the major secondary metabolites in "Penicillium" spores, they are responsible for inflammatory response in lung cells. Originally isolated from "Pennicillum compactum" in 1969, brevianamide A has shown insecticidal activity. Further studies showed that a minor secondary metabolite, brevianamide B, has an epimeric center at the spiro-indoxyl quaternary center. Both were found to fluoresce under long-wave ultraviolet radiation. Furthermore, under irradaton, brevianamide A has been shown to isomerize to brevianamide B. While the biosynthesis has not been conclusively elucidated, brevianamide A and B are constructed from tryptophan, proline, and an isoprene unit. The total synthesis of several brevianamides have been reported, for brevianamide-B and for brevianamide-E. Tests for antibiotic effectiveness against "E. coli", "A. fecalis", "B. subtilis", "S. aureus", and "P. aeruginosa" were negative. Also, no inhibitory action was shown against "A. niger", "A. flavis", "P. crustosum", "F. graminearum", "F. moniliforme", "Alternara" sp., and "Cladosporium" sp. However, some insecticidal activity has been shown in one study, possibly showing some use as an insecticide for food crops | https://en.wikipedia.org/wiki?curid=23175578 |
Brevianamide In mammalian (mice lung cell) studies, brevianamide A has shown to induce cytoxicity in cells. Furthermore, ELISA assays showed elevated levels of tumor necrosis factor-alpha (TNF-A), macrophage inflammatory protein-2 (MIP-2), and interleukin 6 (IL-6). Therefore, brevianamide A may not be a suitable insecticide in food crops. | https://en.wikipedia.org/wiki?curid=23175578 |
Biosynthesis of cocaine The biosynthesis of cocaine has long attracted the attention of biochemists and organic chemists. This interest is partly motivated by the strong physiological effects of cocaine, but a further incentive was the unusual bicyclic structure of the molecule. The biosynthesis can be viewed as occurring in two phases, one phase leading to the N-methylpyrrolinium ring, which is preserved in the final product. The second phase incorporates a C4 unit with formation of the bicyclic tropane core. The biosynthesis begins with L-glutamine, which is derived from L-ornithine in plants. The roles of L-ornithine and L-arginine was confirmed by Edward Leete. Ornithine then undergoes a PLP-dependent decarboxylation to form putrescine. In animals, however, the urea cycle derives putrescine from ornithine. L-Ornithine is converted to L-arginine, which is then decarboxylated via PLP to form agmatine. Hydrolysis of the imine derives "N"-carbamoylputrescine followed with hydrolysis of the urea to form putrescine. The separate pathways of converting ornithine to putrescine in plants and animals have converged. A SAM-dependent "N"-methylation of putrescine gives the "N"-methylputrescine, which then undergoes oxidative deamination by the action of diamine oxidase to yield the aminoaldehyde, which spontaneously cyclizes to "N"-methyl-Δ-pyrrolinium cation. Beyond its role in cocaine, the "N"-methyl-pyrrolinium cation is a precursor to nicotine, hygrine, cuscohygrine, and other natural products | https://en.wikipedia.org/wiki?curid=23176204 |
Biosynthesis of cocaine The additional carbon atoms required for the synthesis of cocaine are derived from acetyl-CoA, by addition of two acetyl-CoA units to the "N"-methyl-Δ-pyrrolinium cation. The first addition is a Mannich-like reaction with the enolate anion from acetyl-CoA acting as a nucleophile towards the pyrrolinium cation. The second addition occurs through a Claisen condensation. This produces a racemic mixture of the 2-substituted pyrrolidine, with the retention of the thioester from the Claisen condensation. In formation of tropinone from racemic ethyl [2,3-13C2]4(Nmethyl- 2-pyrrolidinyl)-3-oxobutanoate there is no preference for either stereoisomer. In the biosynthesis of cocaine, however, only the (S)-enantiomer can cyclize to form the tropane ring system of cocaine. The stereoselectivity of this reaction was further investigated through study of prochiral methylene hydrogen discrimination. This is due to the extra chiral center at C-2. This process occurs through an oxidation, which regenerates the pyrrolinium cation and formation of an enolate anion, and an intramolecular Mannich reaction. The tropane ring system undergoes hydrolysis, SAM-dependent methylation, and reduction via NADPH for the formation of methylecgonine. The benzoyl moiety required for the formation of the cocaine diester is synthesized from phenylalanine via cinnamic acid. Benzoyl-CoA then combines the two units to form cocaine. The synthesis and structure elucidation of cocaine was reported by Richard Willstätter in 1898 | https://en.wikipedia.org/wiki?curid=23176204 |
Biosynthesis of cocaine Willstätter's synthesis derived cocaine from tropinone. Robert Robinson and Edward Leete also made significant contributions. | https://en.wikipedia.org/wiki?curid=23176204 |
Lamb–Mössbauer factor In physics, the (LMF, after Willis Lamb and Rudolf Mössbauer) or elastic incoherent structure factor (EISF) is the ratio of elastic to total incoherent neutron scattering, or the ratio of recoil-free to total nuclear resonant absorption in Mössbauer spectroscopy. The corresponding factor for coherent neutron or X-ray scattering is the Debye–Waller factor; often, that term is used in a more generic way to include the incoherent case as well. When first reporting on recoil-free resonance absorption, Mössbauer (1959) cited relevant theoretical work by Lamb (1939). The first use of the term "Mössbauer–Lamb factor" seems to be by Tzara (1961); from 1962 on, the form "Lamb–Mössbauer factor" came into widespread use. Singwi and Sjölander (1960) pointed out the close relation to incoherent neutron scattering. With the invention of backscattering spectrometers, it became possible to measure the as a function of the wavenumber (whereas Mössbauer spectroscopy operates at a fixed wavenumber). Subsequently, the term "elastic incoherent structure factor" became more frequent. | https://en.wikipedia.org/wiki?curid=23183287 |
Homogenization (chemistry) Homogenization or homogenisation is any of several processes used to make a mixture of two mutually non-soluble liquids the same throughout. This is achieved by turning one of the liquids into a state consisting of extremely small particles distributed uniformly throughout the other liquid. A typical example is the homogenization of milk, where the milk fat globules are reduced in size and dispersed uniformly through the rest of the milk. Homogenization (from "homogeneous;" Greek, "homogenes": "homos," same + "genos," kind) is the process of converting two immiscible liquids (i.e. liquids that are not soluble, in all proportions, one in another) into an emulsion (Mixture of two or more liquids that are generally immiscible). Sometimes two types of homogenization are distinguished: primary homogenization, when the emulsion is created directly from separate liquids; and secondary homogenization, when the emulsion is created by the reduction in size of droplets in an existing emulsion. Homogenization is achieved by a mechanical device called a "homogenizer". One of the oldest applications of homogenization is in milk processing. It is normally preceded by "standardization" (the mixing of several different milking herds and/or dairies to produce a more consistent raw milk prior to processing and to prevent, reduce and delay natural separation of cream from the rest of the emulsion). The fat in milk normally separates from the water and collects at the top | https://en.wikipedia.org/wiki?curid=23183652 |
Homogenization (chemistry) Homogenization breaks the fat into smaller sizes so it no longer separates, allowing the sale of non-separating milk at any fat specification. Milk homogenization is accomplished by mixing large amounts of harvested milk, then forcing the milk at high pressure through small holes. Yet another method of homogenization uses extruders, hammermills, or colloid mills to mill (grind) solids. Milk homogenization is an essential tool of the milk food industry to prevent creating various levels of flavor and fat concentration. Another application of homogenization is in soft drinks like cola products. The reactant mixture is rendered to intense homogenization, to as much as 35,000 psi, so that various constituents do not separate out during storage or distribution. | https://en.wikipedia.org/wiki?curid=23183652 |
Homogenization (biology) Homogenization, in cell biology or molecular biology, is a process whereby different fractions of a biological sample become equal in composition. It can be a disease sign in histopathology, or an intentional process in research: A homogenized sample is equal in composition throughout, so that removing a fraction does not alter the overall molecular make-up of the sample remaining, and is identical to the fraction removed. Induced homogenization in biology is often followed by molecular extraction and various analytical techniques, including ELISA and western blot. Homogenization of tissue in solution is often performed simultaneously with cell lysis. To prevent lysis however, the tissue (or collection of cells, e.g. from cell culture) can be kept at temperatures slightly above zero to prevent autolysis, and in an isotonic solution to prevent osmotic damage. If freezing the tissue is possible, cryohomogenization can be performed under "dry" conditions, and is often the method of choice whenever it is desirable to collect several distinct molecular classes (e.g. both protein and RNA) from a single sample, or combined set of samples, or when long-term storage of part of the sample is desired. Cryohomogenization can be carried out using a supercooled mortar and pestle (classic approach), or the tissue can be homogenized by crushing it into a fine powder inside a clean plastic bag resting against a supercooled solid metal block (more recently developed and more efficient technique) | https://en.wikipedia.org/wiki?curid=23183669 |
Homogenization (biology) High-pressure homogenization is used to isolate the contents of Gram-positive bacteria, since these cells are exceptionally resistant to lysis, and may be combined with high-temperature sterilization. Dounce homogenization is a technique suitable for soft mammalian tissues, while lysis of mammalian cells has also been demonstrated via centrifugation . | https://en.wikipedia.org/wiki?curid=23183669 |
ReAction! Chemistry in the Movies (2009, ) is a nonfiction book about movies, chemistry, and chemistry in the movies by Chemistry Professor Mark Griep and Artist Marjorie Mikasen published by Oxford University Press USA. The authors were awarded an Alfred P. Sloan Foundation grant in the area of Public Understanding of Science to research and write the book. This book is about the chemistry when it is part of the narrative. Most of the examples are contemporary popular feature films while some are documentaries, shorts, silents, and international films. The book uses the dualities personified by the benevolent Dr. Jekyll on one hand and the evil Mr. Hyde on the other to describe how chemists and chemistry are portrayed in the movies. There are 10 chapters, the first five of which have dark chemical themes and the second five of which have bright chemical themes. The chapter titles are: According to several reviews, the book's strength is when it explores what might be the real chemicals that inspired the fictional compounds found in certain movies. | https://en.wikipedia.org/wiki?curid=23183722 |
Beryllium carbide Beryllium carbide, or BeC, is a metal carbide. Similar to diamond, it is a very hard compound. is prepared by heating the elements beryllium and carbon at elevated temperatures (above 900°C). It also may be prepared by reduction of beryllium oxide with carbon at a temperature above 1,500°C: decomposes very slowly in water: The rate of decomposition is faster in mineral acids with evolution of methane. However, in hot concentrated alkali the reaction is very rapid, forming alkali metal beryllates and methane: | https://en.wikipedia.org/wiki?curid=23185684 |
Lineatin is a pheromone produced by female striped ambrosia beetle, "Trypodendron lineatum" Olivier. These kinds of beetles are responsible for extensive damage of coniferous forest infestation in Europe and North America. Since lineatin can act as lures used for mass-trapping of "T. lineatum", it is being studied to apply as a pest control reagent. was first isolated in 1977 by MacConnell. The absolute configuration of the biologically active form was later determined as (+)-(1R,4S,5R,7R)-3,3,7-trimethyl-2,9- dioxatricyclo[3.3.1.0]nonane, whereas other enatinomers process no biological attraction activity. After the absolute structure was determined, lineatin quickly attracted considerable synthetic interests due to its natural occurrence, biological activity, and unique structural features. A few routes describing the total synthesis of lineatin was proposed with yields of 0.5–2%. Recently, a new total synthesis route that adopted a photochemical [2 + 2] cycloaddition approach to construct diastereoselective cyclobutene and a regiocontrolled oxymercuration reaction was proposed. This route achieved in synthesizing highly pure (+)-lineatin (> 99.5% ee) through 14 steps and resulted in 14% overall yield from a homochiral 2(5H)-furanone. (Figure 1 showed the basic outline of this approach). is a monoterprene with unique tricyclic acetal structure. Most of the studies regarding lineatin were focused on the total synthesis; little attentions were put on its biosynthesis | https://en.wikipedia.org/wiki?curid=23186893 |
Lineatin It is suggested that lineatin is derived through oxidation and cyclization of a monoterponid precursor, but no experimental has been done on proving this route. Based on its partial structure similarity to iridoid class of terprenoids, here, a possible biosynthesis pathway was proposed and outlined in figure 2. | https://en.wikipedia.org/wiki?curid=23186893 |
Absinthin is a naturally produced triterpene lactone from the plant "Artemisia absinthium" (Wormwood). It constitutes one of the most bitter chemical agents responsible for Absinthe's distinct taste. The compound shows biological activity and has shown promise as an anti-inflammatory agent, and should not to be confused with thujone, a neurotoxin also found in "Artemisia absinthium". Absinthin's (1) complex structure is classified as a sesquiterpene lactone, meaning it belongs to a large category of natural products chemically derived from 5-carbon "building blocks" (3) derived from isoprene (4). The complete structure consists of two identical monomers (2) that are attached via a suspected naturally occurring Diels Alder reaction occurring at the alkenes on the 5-membered ring of the guaianolide. Total synthesis of (+)-was conducted in 2004 by Zhang, et al. The final yield reported for the synthesis was 18.6% over a course of 10 steps originating from Santonin (1), a commercially available reagent. The basis of the synthesis was the ring expansion of the original 6-membered carbon ring to the 7-membered ring, engendering the formation of the guaianolide monomer (2) scaffold, followed by Diels Alder coupling (3) and final stereochemical modifications resulting in (+)-(4). The full biosynthesis of in "Artemisia absinthium" has not been elucidated, but a great portion of it can be inferred from the natural product precursors required to access Absinthin | https://en.wikipedia.org/wiki?curid=23189674 |
Absinthin While terpenoids like can be said to consist of isoprene "units," isoprene by itself is unstable and does not react directly. Rather, the isoprene units are transferred and reacted as diphosphates. As the nomenclature for terpenes suggests, the first precursor farnesyl diphosphate [A] contains 15 carbons, or 3 isoprene units. Diphosphate departure (1) generates a carbo-cation within the synthase, which can then be attacked by a carbon-carbon double bond at the opposing end of the molecule (2). The first stable intermediate in the biosynthesis pathway in Artemisia is likely Germacrene A [B], which has been previously identified in plant sesquiterpene pathways as a precursor to guaianolides. From there, hydroxylation (3) occurs, followed by oxidation (4) to an aldehyde directly followed by further hydroxylation (5) and formation of a carboxyl group. It is important to note the disappearance of the terminal carbon-carbon double bond after (4), as the reduction of this bond in the final product differentiates the monomer from other Germacrene A downstream products. This reduction does not necessarily occur at step (4), but may occur further downstream. With the carboxyl and hydroxyl group in position, the guaiano-lactone [C] formation via dehydration (7) can occur, as proposed for a general guaianolide pathway | https://en.wikipedia.org/wiki?curid=23189674 |
Absinthin Formation of the sesquiterpene guaianolide monomer [D] from hydroxylation and double bond rearrangement (8,9) is then postulated to directly precede dimerization to [E] via a naturally occurring Diels-Alder reaction [10], which is likely facilitated by the associated synthase even though the reaction itself can occur in good yields spontaneously, albeit slower than typical natural product biosynthesis. While no synthases specific to "Artemisia absinthium" have been sufficiently isolated to recreate this particular sesquiterpene formation in vitro, the general reaction scheme presented here portrays a likely scenario for biosynthesis through the use of terpene intermediates utilized in the biosynthesis of Germacrene A, another sesquiterpene lactone. Enzymatic analogs from terpene biosynthesis which help rationalize the above proposed numbered biosynthetic steps are as follows: | https://en.wikipedia.org/wiki?curid=23189674 |
Dansyl amide is a reactive fluorescent dye that is used in biochemistry and chemistry to label substances with the fluorescent dansyl group. It is also produced as a side-product in the labelling of amino acids with dansyl chloride. | https://en.wikipedia.org/wiki?curid=23193471 |
Sea air has traditionally been thought to offer health benefits associated with its unique odor, which Victorians attributed to ozone. More recently, it has been determined that the chemical responsible for much of the odor in air along certain seashores is dimethyl sulfide, released by microbes. Salts generally do not dissolve in air, but can be carried by sea spray in the form of particulate matter. In Victorian times the quality of sea air was often degraded by pollution from wood and coal-burning ships. Today these fuels are gone, replaced by high sulphur oil in Diesel engines, which generate sulphate aerosols. | https://en.wikipedia.org/wiki?curid=23202425 |
List of ASTM International standards This is a list of ASTM International standards. Standard designations usually consist of a letter prefix and a sequentially assigned number. This may optionally be followed by a dash and the last two digits of the year in which the standard was adopted. Prefix letters correspond to the following subjects: This list may include either current or withdrawn standards. A withdrawn standard has been discontinued by its sponsoring committee. A standard may be withdrawn with or without replacement. | https://en.wikipedia.org/wiki?curid=23204153 |
Glutathione-ascorbate cycle Foyer-Halliwell-Asada pathway The glutathione-ascorbate cycle is a metabolic pathway that detoxifies hydrogen peroxide (HO), which is a reactive oxygen species that is produced as a waste product in metabolism. The cycle involves the antioxidant metabolites: ascorbate, glutathione and NADPH and the enzymes linking these metabolites. In the first step of this pathway, HO is reduced to water by ascorbate peroxidase (APX) using ascorbate (ASC) as the electron donor. The oxidized ascorbate (monodehydroascorbate, MDA) is regenerated by monodehydroascorbate reductase (MDAR). However, monodehydroascorbate is a radical and if not rapidly reduced it disproportionates into ascorbate and dehydroascorbate (DHA). Dehydroascorbate is reduced to ascorbate by dehydroascorbate reductase (DHAR) at the expense of GSH, yielding oxidized glutathione (GSSG). Finally GSSG is reduced by glutathione reductase (GR) using NADPH as the electron donor. Thus ascorbate and glutathione are not consumed; the net electron flow is from NADPH to HO. The reduction of dehydroascorbate may be non-enzymatic or catalysed by proteins with dehydroascorbate reductase activity, such as glutathione S-transferase omega 1 or glutaredoxins. In plants, the glutathione-ascorbate cycle operates in the cytosol, mitochondria, plastids and peroxisomes. Since glutathione, ascorbate and NADPH are present in high concentrations in plant cells it is assumed that the glutathione-ascorbate cycle plays a key role for HO detoxification | https://en.wikipedia.org/wiki?curid=23204882 |
Glutathione-ascorbate cycle Nevertheless, other enzymes (peroxidases) including peroxiredoxins and glutathione peroxidases, which use thioredoxins or glutaredoxins as reducing substrates, also contribute to HO removal in plants. | https://en.wikipedia.org/wiki?curid=23204882 |
Chemical leasing "Chemical Leasing" is a business model that intends to shift the focus from increasing sales volume of chemicals towards a value-added approach. It leads to the more efficient use of chemicals, and to the improved health and safety, environmental, and economic benefits. Find the definition and the examples on www.chemicalleasing.org The term Chemical Leasing is the name of a business model and is NOT the same thing as leasing of chemicals, although it may include leasing operations. The producer mainly sells the functions performed by the chemical and the functional units, such as the number of pieces painted, are the main basis for payment. It is a business model in which a customer engages with a service provider in a strategic, long-term contract to supply and manage the customer's chemical and related services. Chemical Leasing applied in many companies, but sometimes under different names. Similar concepts: eco-efficient services, product-service systems, pay-per-use, circular economy, performance-based, functional-based, service-oriented, chemicals-as-a-service, etc. In case of the doubt, it is better to check the official UNIDO definition of Chemical Leasing: promotes the sustainable management of chemicals. By shifting the focus from increasing the sales volume of chemicals towards a more value-added approach, it is an illustration of extended producer responsibility | https://en.wikipedia.org/wiki?curid=23211852 |
Chemical leasing The chemical company supplies chemicals for a specific service, such as coatings, adhesives, washing agents, solvents, and also advises the user on its best use. Built on strong cooperation between partners and based on mutual trust, it increases the efficient use of chemicals, reduces the risks to human health brought about by their use, improves the economic and environmental performance of participating companies and ultimately enhances business performance. At the Earth Summit 2002 on sustainable development, the international community agreed on the goal of ensuring that, by the year 2020, chemicals will be produced and used in ways that minimize significant adverse impacts on human health and the environment. As a consequence the United Nations Environmental Programme (UNEP) decided to develop of the Strategic Approach to International Chemicals Management (SAICM) in 2003. In 2006 at the International Conference on Chemicals Management (ICCM) in Dubai, the signing countries committed themselves to promote the sound management of chemicals and hazardous wastes at all levels. The Austrian government has played an important role in promoting chemicals management based on resource efficiency and precaution. When Austria held the Presidency of the European Union during the first half of 2006, chemicals policy was on top of the environmental agenda. Austria continues to promote chemical leasing | https://en.wikipedia.org/wiki?curid=23211852 |
Chemical leasing The Federal Environment Agency (UBA) of Germany proposed to promote chemical leasing in its "Sustainable Chemicals" paper. In 2004, the United Nations Industrial Development Organization (UNIDO) and the Austrian Ministry of Environment decided to jointly support chemical leasing through a number of global projects. In partnership with National Cleaner Production Centers, UNIDO has implemented chemical leasing projects in Austria, Egypt, Mexico, and Russia. Since then, pilot projects have been conducted in Latin and South America, Africa, Europe and Asia. Nowadays, more than 100 companies worldwide have included Chemical Leasing in their business strategies. Chemical Leasing can be applied in many industries and processes, ranging from car manufacturing to cleaning operations, wastewater treatment, textiles, beverage and food production. Some examples of the successful Chemical Leasing collaboration between the chemical user and the chemical supplier can be found here: http://chemicalleasing-toolkit.org/node/8 A Joint Declaration of Intent on Chemical Leasing was signed between UNIDO, Austria, Germany and Switzerland in November 2016. PERO Innovative Services GmbH together with SAFECHEM Europe GmbH, a subsidiary of The Dow Chemical Company, have supported Automobiltechnik Blau in metal cleaning to use cost-efficient machines, lower the energy consumption and chemical usage. Akzo Nobel Powder Coatings S.A.E has supported the chemical leasing of powder coating in Egypt to ABB ARAB | https://en.wikipedia.org/wiki?curid=23211852 |
Chemical leasing Environmental benefits are said to include recycling of powder waste, compliance with environmental regulations, and enhancement of supply chain management. Find more successful Chemical Leasing examples here: http://chemicalleasing-toolkit.org/node/8 The reversal of the burden of proof is a key component of the Registration, Evaluation, Authorisation and Restriction of Chemicals (REACH) system leading to a "no data – no market" concept, obliging producers or importers of substances to deliver documentation regarding properties of chemicals and possible risks during their application as a pre-condition for market access. The OECD Conference in Vienna in 2003 Nov. reiterated that, "... The new EU chemicals policy (REACH) will require a new relationship between provider and user ..." According to Thomas Jakl, Chairman of the European Chemical Agency (ECHA), chemical leasing paves the way to comply with REACH obligations. and REACH share the same philosophy of ensuring compliance with a duty of care (REACH recital 16), as a tool to demonstrate adequate control (REACH para 60). They are mutually supportive in developing rules for sharing costs, and ensuring that chemicals are handled properly. Both are involve several different stages of the supply chain. There is a strong effort by the Austrian and German Governments to bring chemical leasing within the purview of EU Chemicals policy and regulations. projects are divided into planning, implementation, evaluation and dissemination stages, based on a Deming Cycle | https://en.wikipedia.org/wiki?curid=23211852 |
Chemical leasing The planning stage consists of a preparatory phase, a process optimisation phase and a design phase. In this stage, discussions around the leasing model, its cost implications versus quality and environmental benefits, commercial terms, and conditions begin. A baseline audit is performed, and a report presented to the factory management. This audit outlines the potential for improvements and forms the basis of defining the key performance indicators (KPIs). The resources needed to fulfil improvements are also defined. The implementation stage starts with the signing of a chemical leasing agreement that defines the scope and conditions, unit of payment, KPIs, roles, and responsibilities. The chemical company supervises the chemical process, transporting and managing the inventory, laboratory management, improving process controls, record keeping, and training workers. Periodic checks and inspections are carried out independently to verify that the implementation is proceeding on expected lines. At the end of the implementation phase, progress is evaluated, often by an external party to secure objectivity. Finally, any project benefits are quantified and learning is documented, to provide input for future projects. 16 January 2018 - The United Nations Industrial Development Organization announced the fourth Global Chemical Leasing Award. The award ceremony will take place on 6 November 2018 in Vienna, Austria | https://en.wikipedia.org/wiki?curid=23211852 |
Chemical leasing It will be part of the Green Chemistry Conference 2018 within the Trio Presidency of the Council of the European Union (EU) programme, “Smart and Sustainable Europe”, held during Austria's EU Presidency. Companies and individuals are invited to submit applications for the award in three categories: case studies (for companies), research, and special innovation. The call for applications is open until 15 August 2018. More information can be found at www.chemicalleasing.org The Global Chemical Leasing Award has been launched in 2010. The Award intends to further enhance the global visibility of Chemical Leasing, acknowledge best practices and inspire companies and individuals around the globe to apply the Chemical Leasing business concept by reducing the inefficient use and over-consumption of chemicals and developing strong business partnerships and innovation along the entire supply chain.</ref> The awards took place in 2010 (Prague), in 2012 (Frankfurt-am-Main), and in 2014 (Vienna). | https://en.wikipedia.org/wiki?curid=23211852 |
Gram per cubic centimetre The gram per cubic centimetre is a unit of density in the CGS system, commonly used in chemistry, defined as mass in grams divided by volume in cubic centimetres. The official SI symbols are g/cm, g·cm, or g cm. It is equivalent to the units gram per millilitre (g/mL) and kilogram per litre (kg/L). The density of water is about 1 g/cm, since the gram was originally defined as the mass of one cubic centimetre of water at its maximum density at 4 °C. 1 g/cm is equivalent to: 1 kg/m = 0.001 g/cm(exactly) 1 lb/ft ≈ 0.01602 g/cm (approximately) 1 oz/gal ≈ 0.00749 g/cm (approximately) | https://en.wikipedia.org/wiki?curid=23215561 |
Hantzsch–Widman nomenclature Hantzsch–Widman nomenclature, also called the extended Hantzsch–Widman system, is a type of systematic chemical nomenclature used for naming heterocyclic parent hydrides having no more than ten ring members. Some common heterocyclic compounds have retained names that do not follow the Hantzsch–Widman pattern. A Hantzsch–Widman name will always contain a prefix, which indicates the type of heteroatom present in the ring, and a stem, which indicates both the total number of atoms and the presence or absence of double bonds. The name may include more than one prefix, if more than one type of heteroatom is present; a multiplicative prefix if there are several heteroatoms of the same type; and locants to indicate the relative positions of the different atoms. Hantzsch–Widman names may be combined with other aspects of organic nomenclature, to indicate substitution or fused-ring systems. The Hantzsch–Widman prefixes indicate the type of heteroatom(s) present in the ring. They form a priority series: If there is more than one type of heteroatom in the ring, the prefix that is higher on the list comes before the prefix that is lower on the list. For example, "oxa" (for oxygen) always comes before "aza" (for nitrogen) in a name. The priority order is the same as that used in substitutive nomenclature, but is recommended only for use with a more restricted set of heteroatoms (see also below) | https://en.wikipedia.org/wiki?curid=23216525 |
Hantzsch–Widman nomenclature All of the prefixes end in "a": In (but not in some other methods of naming heterocycles), the final "a" is elided when the prefix comes before a vowel. The heteroatom is assumed to have its standard bonding number for organic chemistry while the name is being constructed. The halogens have a standard bonding number of one, and so a heterocyclic ring containing a halogen as a heteroatom should have a formal positive charge. In principle, lambda nomenclature could be used to specify a non-standard valence state for a heteroatom but, in practice, this is rare. The choice of stem is quite complicated, and not completely standardised. The main criteria are: Notes on table: is named after the German chemist Arthur Hantzsch and the Swedish chemist Oskar Widman, who independently proposed similar methods for the systematic naming of heterocyclic compounds in 1887 and 1888 respectively. It forms the basis for many common chemical names, such as dioxin and benzodiazepine. | https://en.wikipedia.org/wiki?curid=23216525 |
DRDC Suffield is a major Canadian military research facility located north of Suffield, Alberta and is one of eight centres making up Defence Research and Development Canada (DRDC). The research facility commenced operations on June 11, 1941 as a joint British/Canadian biological and chemical defence facility as the Experimental Station Suffield under the administration of the Canadian Army. By the end of the Second World War, the station employed 584 personnel trained in chemistry, physics, meteorology, mathematics, pharmacology, pathology, bacteriology, physiology, entomology, veterinary science, mechanical and chemical engineering. In 1946, the station was placed completely in the hands the Canadian Army when the British withdrew their support. The responsibility for administrating the station, including the Suffield Block, was transferred to the Defence Research Board on April 30, 1947 by Order in Council PC 101/1727. In August 1950, the station was renamed to the Suffield Experimental Station (SES). In July 1967, the Suffield Experimental Station was renamed to the Defence Research Establishment Suffield (DRES). On December 1, 1971, the Canadian Forces Base Suffield (CFB Suffield) was officially created and allocated to Mobile Command. A number of personnel and support functions were transferred from DRES to CFB Suffield and CFB Suffield was co-located with the Research Establishment | https://en.wikipedia.org/wiki?curid=23218535 |
DRDC Suffield In 1974, the Defence Research Board evolved into the Research and Development Branch which was administered under the Assistant Deputy Minister Materiel of the Canadian Department of National Defence. Another reorganization followed on April 1, 2000 when the Research and Development Branch was placed under the Assistant Deputy Minister Science & Technology and renamed to Defence Research and Development Canada (DRDC). Research areas at the Centre focus on military engineering, mobility and autonomous systems, weapons system evaluation and chemical-biological defence. These scientific and technological activities are supported by meteorological, photographic, information, design and development, materiel management and field support services. also hosts the Counter Terrorism Technology Centre (CTTC) which is a core component in enabling Canada to respond to domestic and international chemical, biological, radiological, nuclear and explosive (CBRNE) incidents. Inspections by site visit teams from the Organisation for the Prohibition of Chemical Weapons and annual visits by the Biological and Chemical Defence Review Committee ensure that DRDC Suffield's training and research and development activities in the area of chemical and biological defence are all compliant with Canada's obligations under the Chemical Weapons Convention and the Biological Weapons Convention and are carried out in a professional manner, with no threat to humans nor to the environment. | https://en.wikipedia.org/wiki?curid=23218535 |
Biomarkers of exposure assessment Biomarkers are chemicals, metabolites, susceptibility characteristics, or changes in the body that relate to the exposure of an organism to a chemical. They have the ability to identify if an exposure has occurred, the route of exposure, the pathway of exposure, and the resulting effects of the exposure. The use of biomarkers in exposure studies is also referred to as biomonitoring. When dealing with exposure assessment, there are three types of biomarkers that can be useful, biomarkers of susceptibility, biomarkers of exposure, and biomarkers of effect. Biomarkers of exposure are the most widely used because they can provide information on the route, pathway, and sometimes, even the source of exposure. Biomarkers of susceptibility are indicators of the natural characteristics of an organism that make it more susceptible to the effects of an exposure to a chemical. They can help define what sensitivities are more susceptible as well as critical times when exposures can be most detrimental. For example, the exhalation strength of an asthmatic will indicate how susceptible that person would be to the respiratory effects of exposure to brevetoxin, the toxic compound produced during a red tide. Biomarkers of exposure are the actual chemicals, or chemical metabolites, that can be measured in the body or after excretion from the body to determine different characteristics of an organism’s exposure. For example, a person or fish’s blood can be tested to see the levels of lead and therefore determine the exposure | https://en.wikipedia.org/wiki?curid=23222254 |
Biomarkers of exposure assessment Biomarkers of effect are the quantifiable changes that an individual endures, which indicates an exposure to a compound and may indicate a resulting health effect. For example, after exposure to DDT, an organochlorine insecticide known to cause problems in the reproductive system, a woman may experience miscarriages, which can be linked to her previous exposure. Biomarkers of exposure are the most widely used because they can provide information on the route, pathway, and sometimes, even the source of exposure. These indicators also allow researchers to work forward in time to determine an exposure, and prevent it from causing further damage. This is unlike biomarkers of effect, in which a scientist may work backwards to determine if and what kind of exposure took place, but may be too late to change anything. However, biomarkers of effect are useful for future studies on the chemical(s) of interest and the results may aid in stricter laws or guidelines regarding the chemical(s). Biomarkers must be evaluated in terms of their ability to predict and quantify exposure and dose. There are certain properties that are desirable when linking a biomarker with an exposure. These include high specificity (one exposure to one biomarker), linear relationship across time, strong correlation with a health effect, inexpensive study, and consistency (the same exposure will produce the same concentration of the biomarker every time) | https://en.wikipedia.org/wiki?curid=23222254 |
Biomarkers of exposure assessment Without these ideal characteristics, the use of biomarkers as a strong predictor of exposure has limitations. Many different classes of compounds can be measured in different tissues and parts of the body. From breath to hair to saliva, almost every tissue in the body has been tested as a biomarker of exposure and almost every major environmental pollutant can be identified by biomarkers, including volatile organic chemicals (VOCs) and metals like arsenic or lead. It all depends on the chemical structures and reactivity of the compound with the makeup of its storage space. The following table identifies major environmental pollutants and their biomarker tissue or organ | https://en.wikipedia.org/wiki?curid=23222254 |
Limiting pressure velocity is a tribological term relating to the maximum temperature and compression that an assembly with rubbing surfaces can bear without failing.Pressure-limiting valves are a type of pressure control valve. They safeguard the system against excessive system pressure or limit the operation pressure. Pre-load valves, also called sequence valves are a type of pressure control valve. They generate a largely constant pressure drop between the inlet and outlet on the valve. In the opposite direction the flow can pass freely. In the normal position the valve has minor leakage. | https://en.wikipedia.org/wiki?curid=23226437 |
Marketing Authorisation Application (MAA) is an application submitted by a drug manufacturer seeking marketing authorisation, that is permission to bring a medicinal product (for example, a new medicine or generic medicine) to the market. MAA is part of the official procedure before the Medicines and Healthcare products Regulatory Agency in the United Kingdom and the Committee for Medicinal Products for Human Use of the European Medicines Agency, a specialised agency of the European Commission. In the United States, the equivalent process is called New Drug Application. | https://en.wikipedia.org/wiki?curid=23226758 |
Colorimetry (chemical method) In physical and analytical chemistry, colorimetry or colourimetry is a technique "used to determine the concentration of colored compounds in solution." A colorimeter is a device used to test the concentration of a solution by measuring its absorbance of a specific wavelength of light (not to be confused with the tristimulus colorimeter used to measure colors in general). To use the colorimeter, different solutions must be made, including a control or reference of known concentration. With a visual colorimeter, for example the Duboscq colorimeter illustrated, the length of the light path through the solutions can be varied while filtered light transmitted through them is compared for a visual match. The concentration times path length is taken to be equal when the colors match, so the concentration of the unknown can be determined by simple proportions. Nessler tubes work on the same principle. There are also electronic automated colorimeters; before these machines are used, they must be calibrated with a cuvette containing the control solution. The concentration of a sample can be calculated from the intensity of light before and after it passes through the sample by using the Beer–Lambert law. Photoelectric analyzers came to dominate in the 1960s. The color or wavelength of the filter chosen for the colorimeter is extremely important, as the wavelength of light that is transmitted by the colorimeter has to be the same as that absorbed by the substance being measured | https://en.wikipedia.org/wiki?curid=23228834 |
Colorimetry (chemical method) For example, the filter on a colorimeter might be set to red if the liquid is blue. A colorimeter is a device used to test the concentration of a solution by measuring its absorbance of a specific wavelength of light. To use this device, different solutions must be made, and a control (usually a mixture of distilled water and another solution) is first filled into a cuvette and placed inside a colorimeter to calibrate the machine. Only after the device has been calibrated you can use it to find the densities and/or concentrations of the other solutions. You do this by repeating the calibration, except with cuvettes filled with the other solutions. The filter on a colorimeter must be set to red if the liquid is blue. The size of the filter initially chosen for the colorimeter is extremely important, as the wavelength of light that is transmitted by the colorimeter has to be same as that absorbed by the substance. Colorimetric assays use reagents that undergo a measurable color change in the presence of the analyte. They are widely used in biochemistry to test for the presence of enzymes, specific compounds, antibodies, hormones and many more analytes. For example, | https://en.wikipedia.org/wiki?curid=23228834 |
Chaudhry Abdul Majeed (born:1937; Urdu: چودہری عبد لمجيد ) was a Pakistani nuclear chemist and a nuclear weapon and reactor expert. He is known as one of the pioneers of Pakistan's nuclear deterrent programme, and has worked closely with former PAEC Chairman Munir Ahmad Khan's plutonium reprocessing project. He rose to prominence when he was apprehended by Pakistan's intelligence agencies in a joint operation in late October of 2001. Majeed was also one of the founding members of Sultan Bashiruddin Mahmood's Ummah Tameer-e-Nau charity; an NGO which caused an international embarrassment for Pakistan. Majeed was educated in Lahore, Punjab, British Indian Empire. In 1955, he attended University of Engineering and Technology of Lahore, and took his double B.Sc. in Mathematics and Chemistry in 1959. The same year, he was admitted to the High-Tension Laboratory, a physics department for advanced courses in Nuclear sciences, at the Government College University, where he gained his M.Sc. in Nuclear Chemistry. In 1964, Majeed went to Belgium on a scholarship awarded by the PAEC and attended Katholieke Universiteit Leuven, from which he received his D.Sc. in Nuclear Chemistry in 1968. He continued his academic research at the plutonium facility in Belgium in the late 1960s. Majeed received training at the "Tihange" and "Doel" nuclear facilities. As a senior scientist he had access to classified documentations on sensitive plutonium technology which is critical to develop a nuclear weapon | https://en.wikipedia.org/wiki?curid=23230424 |
Chaudhry Abdul Majeed Majeed also worked at the International Center for Theoretical Physics, invited by Abdus Salam, during the 1970s and early 1980s. At ICTP, Majeed taught advanced courses in chemistry and mathematics. At ICTP, he published numerous research papers in the field of Spectroscopy, neutron and particle detectors. Majeed returned to Pakistan in 1974 after India had conducted a surprise nuclear test, codenamed "Pokhran-I". At the Pakistan Institute of Nuclear Science and Technology, he was assigned to the Nuclear Chemistry Division led by Iqbal Hussain Qureshi. In 1974, Majeed was a part of Munir Ahmad Khan's team that had supervised the criticality of second nuclear pile —PARR-II reactor. After the construction of the third nuclear pile—PARR-III, also known as The New-Labs; Majeed was the first technical director, and was part of a team that supervised the reactor's criticality. An expert plutonium technology, Majeed, as junior scientist, is known for his contribution in plutonium reprocessing plant and the plutonium nuclear fuel cycle technology. Majeed was also a part of a team at the New Labs that had succeeded to attain the fresh supplies of weapon-grade plutonium isotopes, produced by the reactor. In 1990, Majeed was promoted and was made Director-general of Nuclear Chemistry Division (NCD) by Munir Ahmad Khan. Throughout the 1990s, Majeed was responsible for underground work of nuclear reactors "Khushab-I" and "CHASNUPP-I" commercial nuclear power plant | https://en.wikipedia.org/wiki?curid=23230424 |
Chaudhry Abdul Majeed There, he was the director of Radiation and Nuclear Safety Division and was omitted from the weapons development teams. He published extensively in the 1980s and 1990s on nuclear detectors and the use of x-ray diffraction, fluorescence, and crystallography to study a wide variety of materials and elements, including stainless steel, uranium, plutonium, and thorium. Due to his work for the State, he was conferred with Tamgha-e-Imtiaz which was awarded to him by Prime minister Nawaz Sharif in 1998. American CIA intelligence officials said that the first interrogation of the two Pakistani scientists concluded that Mahmood and Majeed did not know enough to help build a nuclear weapon. "These two guys were nuclear scientists who didn't know how to build one themselves," the American official said. "If you had to have guys go bad, these are the guys you'd want. They didn't know much." The NGO scandal heavily disturbed his imaged and his private life also. Even though, he heavily cooperated with intelligence agencies in hoping of freedom and went back to PAEC; he was declined to give any partial freedom. He was harshly interrogated for a long time which also resulted in his death. Bashir Syed, former President of the Association of Pakistani Scientists and Engineers of North America (APSENA), said: "I know both of these persons and can tell you there is not an iota of truth that both these respected scientists and friends will do anything to harm the interest of their own country." | https://en.wikipedia.org/wiki?curid=23230424 |
Polymorphs of silicon carbide Many compound materials exhibit polymorphism, that is they can exist in different structures called polymorphs. Silicon carbide (SiC) is unique in this regard as more than 250 polymorphs of silicon carbide had been identified by 2006, with some of them having a lattice constant as long as 301.5 nm, about one thousand times the usual SiC lattice spacings. The polymorphs of SiC include various amorphous phases observed in thin films and fibers, as well as a large family of similar crystalline structures called polytypes. They are variations of the same chemical compound that are identical in two dimensions and differ in the third. Thus, they can be viewed as layers stacked in a certain sequence. The atoms of those layers can be arranged in three configurations, A, B or C, to achieve closest packing. The stacking sequence of those configurations defines the crystal structure, where the unit cell is the shortest periodically repeated sequence of the stacking sequence. This description is not unique to SiC, but also applies to other binary tetrahedral materials, such as zinc oxide and cadmium sulfide. A shorthand has been developed to catalogue the vast number of possible polytype crystal structures: Let us define three SiC bilayer structures (that is 3 atoms with two bonds in between in the pictures below) and label them as A, B and C | https://en.wikipedia.org/wiki?curid=23239104 |
Polymorphs of silicon carbide Elements A and B do not change the orientation of the bilayer (except for possible rotation by 120°, which does not change the lattice and is ignored hereafter); the only difference between A and B is shift of the lattice. Element C, however, twists the lattice by 60°. Using those A,B,C elements, we can construct "any" SiC polytype. Shown above are examples of the hexagonal polytypes 2H, 4H and 6H as they would be written in the Ramsdell classification scheme where the number indicates the layer and the letter indicates the Bravais lattice. The 2H-SiC structure is equivalent to that of wurtzite and is composed of only elements A and B stacked as ABABAB. The 4H-SiC unit cell is two times longer, and the second half is twisted compared to 2H-SiC, resulting in ABCB stacking. The 6H-SiC cell is three times longer than that of 2H, and the stacking sequence is ABCACB. The cubic 3C-SiC, also called β-SiC, has ABC stacking. The different polytypes have widely ranging physical properties. 3C-SiC has the highest electron mobility and saturation velocity because of reduced phonon scattering resulting from the higher symmetry. The band gaps differ widely among the polytypes ranging from 2.3 eV for 3C-SiC to 3 eV in 6H SiC to 3.3 eV for 2H-SiC. In general, the greater the wurtzite component, the larger the band gap. Among the SiC polytypes, 6H is most easily prepared and best studied, while the 3C and 4H polytypes are attracting more attention for their superior electronic properties | https://en.wikipedia.org/wiki?curid=23239104 |
Polymorphs of silicon carbide The polytypism of SiC makes it nontrivial to grow single-phase material, but it also offers some potential advantages - if crystal growth methods can be developed sufficiently then heterojunctions of different SiC polytypes can be prepared and applied in electronic devices. All symbols in the SiC structures have a specific meaning: The number 3 in 3C-SiC refers to the three-bilayer periodicity of the stacking (ABC) and the letter C denotes the cubic symmetry of the crystal. 3C-SiC is the only possible cubic polytype. The wurtzite ABAB... stacking sequence is denoted as 2H-SiC, indicating its two-bilayer stacking periodicity and hexagonal symmetry. This periodicity doubles and triples in 4H- and 6H-SiC polytypes. The family of rhombohedral polytypes is labeled R, for example, 15R-SiC. | https://en.wikipedia.org/wiki?curid=23239104 |
Sand rammer A sand rammer is a piece of equipment used in foundry sand testing to make test specimen of molding sand by compacting bulk material by free fixed height drop of fixed weight for 3 times. It is also used to determine compactibility of sands by using special specimen tubes and a linear scale. consists of calibrated sliding weight actuated by cam, a shallow cup to accommodate specimen tube below ram head, a specimen stripper to strip compacted specimen out of specimen tube, a specimen tube to prepare the standard specimen of 50 mm diameter by 50 mm height or 2 inch diameter by 2 inch height for an AFS standard specimen. The cam is actuated by a user by rotating the handle, causing a cam to lift the weight and let it fall freely on the frame attached to the ram head. This produces a standard compacting action to a pre-measured amount of sand. Demonstration of this apparatus can be seen here: Variety of standard specimen for Green Sand and Silicate based (CO)sand are prepared using a sand rammer along with accessories The object for producing the standard cylindrical specimen is to have the specimen become 2 inches high (plus or minus 1/32 inch) with three rams of the machine. After the specimen has been prepared inside the specimen tube, the specimen can be used for various standard sand tests such as the permeability test, the green sand compression test, the shear test, or other standard foundry tests | https://en.wikipedia.org/wiki?curid=23251097 |
Sand rammer The sand rammer machine can be used to measure compactability of prepared sand by filling the specimen tube with prepared sand so that it is level with the top of the tube. The tube is then placed under the ram head in the shallow cup and rammed three times. Compactability in percentage is then calculated from the resultant height of the sand inside the specimen tube. A rammer is mounted on a base block on a solid foundation, which provides vibration damping to ensure consistent ramming. Prerequisite equipments for sand rammer may vary from case to case basis or testing scenario: Case 1: If the prepared sand is ready Case 2: Experiment by preparing new sand sample If sand needs to be prepared before making specimen following equipments may be needed Case 3: For low compressive strength sands and mixtures: | https://en.wikipedia.org/wiki?curid=23251097 |
Superstructure (condensed matter) In solid state physics, a superstructure is some additional structure that is superimposed on a given crystalline structure. A typical and important example is ferromagnetic ordering. In a wider sense, the term "superstructure" is applied to polymers and proteins to describe ordering on a length scale larger than that of monomeric segments. In a crystal, a superstructure manifests itself through additional reflections in diffraction patterns, e.g., in low energy electron diffraction (LEED) or X-ray diffraction experiments. Often a set of weak diffraction spots appears between the stronger spots belonging to what is referred to as the substructure. In some cases a phase transition occurs, e.g., at higher temperatures, where the superstructure disappears and the material reverts to the simpler substructure. Not all compounds exhibit a superstructure. The superspots in diffraction patterns represent a "modulation" of the substructure that causes the inherent translation symmetry of the (substructure) lattice to be violated slightly or the size of the repeat motif of the structure to be increased. One could speak of symmetry breaking of the translation symmetry of the lattice, although rotational symmetry may be lost simultaneously. If the superspots are located at "simple fractions" of the vectors of the reciprocal lattice of the substructure, e.g., at q=(½,0,0), the resulting broken symmetry is a multiple of the unit cell along that axis. Such a modulation is called a commensurate superstructure | https://en.wikipedia.org/wiki?curid=23251878 |
Superstructure (condensed matter) In some materials, superspots will occur at positions that do not represent a simple fraction, say q=(0.5234,0,0). In this case the structure strictly speaking has lost all translational symmetry in a particular direction. This is called an incommensurate structure. There are basically three types of superstructures in crystals: When a crystalline material that contains atoms with uncompensated electron spins is cooled down, ordering of these spins generally occurs once the thermal energy is small enough not to overrule the interactions between neighboring spins. If the ordering does not exhibit the same symmetry as the original unit cell of the crystallographic lattice, a superstructure will result. In this case, the superspots are typically only visible in neutron diffraction patterns, because the neutron is scattered both by the nucleus and by the magnetic moments of the electron spins. Many alloys of elements that resemble each other chemically will form a structure at higher temperatures where the two elements occupy similar positions in the lattice at random. At lower temperatures ordering may occur where crystallographic positions are no longer equivalent because one element preferentially occupies one site and the other the other. This partial ordering process may lower the translation symmetry and result in a different, larger unit cell | https://en.wikipedia.org/wiki?curid=23251878 |
Superstructure (condensed matter) In some transitions a number of atoms occupying crystallographic positions that were originally equivalent will move away slightly from their ideal positions according to a certain pattern. This pattern or repeat motif may span multiple unit cells. The cause of this phenomenon is the small changes in chemical bonding that favor formations of semi-regular and larger clusters of atoms. Although having the undistorted substructure, these materials are typically 'unsaturated' in the sense that one of the bands in the band structure is only partially filled. The distortion changes the band structure, in part splitting the bands up into smaller bands that can be more completely filled or emptied to lower the energy of the system. This process may not go to completion, however, because the substructure only allows for a certain amount of distortion. Superstructures of this type are often incommensurate. A good example is found in the structural transitions of 1T-TaS, a compound with a partially filled, narrow d band (Ta(IV) has a d configuration). | https://en.wikipedia.org/wiki?curid=23251878 |
Genosome A genosome (also known as a lipoplex) is a lipid and DNA complex that is used to deliver genes. It can be a form of non-viral gene therapy as the complex does not require any components of a virus in order to transport genetic material. In presence of CT-DNA, genosomes can form through surface electrostatic interaction. | https://en.wikipedia.org/wiki?curid=23257752 |
Southern Research is a not-for-profit US 501(c)(3) research organization that conducts basic and applied research for commercial and non-commercial organizations across four divisions: Drug Development, Drug Discovery, Energy & Environment, and Engineering. was founded in Birmingham, Alabama, on October 11, 1941 by Thomas Martin as the Alabama Research Institute. Although Martin was named chairman of the newly chartered organization in December, 1941, activities were put on hold in the aftermath of the attack on Pearl Harbor and the beginning of US involvement in World War II. Two years later, in December 1943, with a promise of support from the Alabama Power Company, Martin reengaged the Alabama's industrial leaders and received over $100,000 in philanthropic donations. Alabama Power Company pledged an additional US$15,000 per year for five years, $75,000 total, and this was enough for the organization to finance laboratory space and hire researchers and staff. The following year, 1944, the decision was made to change the institute's name from Alabama Research Institute, to Institute. Around this same time, Institute hired its first director, Wilbur Lazier. Though he only stayed in this role for four years, Lazier is credited with recruiting many figures that shaped the history of the organization, including Howard E. Skipper. celebrated its 75th Anniversary in October, 2016 | https://en.wikipedia.org/wiki?curid=23262740 |
Southern Research In celebration of this milestone the director of National Institutes of Health (NIH), Francis Collins, produced a video congratulating the organization on its anniversary. In May 2019, Arthur J. Tipton stepped down as the president and CEO of Southern Research. Previously, he worked in the pharmaceutical and biotech industries for 25 years. From 1993 to 2004, Tipton held roles of increasing responsibility at Durect Corporation, including that of senior vice president of biodegradable systems, chief operating officer, vice president of Southern BioSystems, and president of Birmingham Polymers. In 2013, Arthur J. Tipton, CEO of was inducted as a fellow into the National Academy of Inventors. Southern Research's Drug Development division is the largest of the organization's four divisions. Set up like a contract research organization (CRO), provides commercial and government clients with nonclinical and clinical trial support services. They offer studies including both in vitro and in vivo testing of small molecule compounds, vaccines, biologics, and other test articles in therapeutic areas including infectious disease, CNS and cancer. Current service areas include: Bioanalytical Analysis; Anticancer Efficacy Services; Immunology; Infectious Disease; Pathology; and Consulting. In 2016, hired Tim McGrath to serve as the new vice president of Drug Development. Southern Research's Drug Discovery division conducts research focused on oncology, infectious disease, and neuroscience | https://en.wikipedia.org/wiki?curid=23262740 |
Southern Research Their current service areas include: High Throughput Screening (THS), Chemistry, Oncology, Infectious Disease, Neuroscience, and the Center for Neuromolecular Research. is a founding member of the Alabama Drug Discovery Alliance (ADDA) along with the University of Alabama at Birmingham School of Medicine (SOM). The UAB Center for Clinical and Translational Science (CCTS), and the UAB Comprehensive Cancer Center (CCC) are also crucial contributors to the ADDA. Mark J. Suto is vice president of Drug Discovery at Southern Research. He has been named a Fellow of the National Academy of Inventors (NAI) in recognition of his wide-ranging contributions to pharmaceutical research and drug discovery efforts. cancer research program was started in 1946 with a $25,000 philanthropic donation from Mobile, AL businessman, Ben E. May. The organization's scientists are credited with the discovery of seven Food and Drug Administration (FDA) approved anti-cancer drugs, including carmustine, lomustine, dacarbazine developed by Y Fulmer Shealy, fludarabine, amifostine, clofarabine and the latest pralatrexate (approved in 2009). Notable cancer researchers who worked at the institute include Y Fulmer Shealy Howard E. Skipper, John Montgomery, Frank Schabel and Lee Bennett Jr. Clofarabine is a nucleoside discovered at that eventually received FDA approval | https://en.wikipedia.org/wiki?curid=23262740 |
Southern Research Clofarabine, a second-generation nucleoside analogue received accelerated approval from the US FDA at the end of 2004 for the treatment of paediatric patients 1–21 years old with relapsed or refractory acute lymphoblastic leukaemia after at least two prior regimens. It is the first such drug to be approved for paediatric leukaemia in more than a decade, and the first to receive approval for paediatric use before adult use. Pralatrexate is another anticancer drug whose discovery was a result of contributions from medicinal chemists at along with chemists from SRI International and Memorial Sloan-Kettering Cancer Center. The US FDA announced the approval of pralatrexate in 2009 for the treatment of relapsed or refractory peripheral T-cell lymphoma (PTCL). Research on drugs of this class began at SRI International in the 1950s. Pralatrexate was first prepared there by Dr. Joseph DeGraw and Dr. William Colwell. Dr. Robert Piper at synthesized the key starting material (a bromomethyl compound) which was used to prepare the intermediates needed to make multigram quantities of high purity final compound. Multiple issued patents on this compound are jointly owned by Southern Research, SRI International and Memorial Sloan Kettering and licensed to Allos Therapeutics. MLP was founded by the NIH to fund research aimed at identifying new chemical probes against biological targets that might be amenable for drug therapy | https://en.wikipedia.org/wiki?curid=23262740 |
Southern Research was one of eight extramural institutes selected for this initiative along with the Broad Institute, Sanford-Burnham Medical Research Institute, Johns Hopkins University, Scripps Research Institute, Vanderbilt University, University of New Mexico and the University of Kansas. In addition the MLP initiative also included an NIH intramural site: the National Center for Chemical Genomics (NCGC). Southern Research's Energy & Environment division focuses on technology for clean energy, clean air, and clean water. develops and tests air and water emissions control technologies for leading utilities, industrial manufacturers, municipal water utilities, and related trade organizations. The division has also historically partnered with private sector firms and government agencies to develop new technologies that transform energy generation, chemical synthesis, and air and water purification. In 2015, William J. Grieco joined as vice president of Energy & Environment. In 2016, hired senior nuclear engineer, Lance Kim, Ph.D., to spearhead the organization’s expansion into Generation IV nuclear reactor research. engineers have worked with the National Aeronautics and Space Administration (NASA), the U.S. Military and other organizations | https://en.wikipedia.org/wiki?curid=23262740 |
Southern Research Current areas include: Non destructive evaluation of materials; Chemistry and Physics of Materials; Electrical, EO/IR, and Mechanical Systems; Hypersonic Structures; Space Structures Characterization; Mechanical Testing of Materials Structures and Components; and Thermal Testing of Materials. Michael D. Johns is the vice president of Engineering at Southern Research. He also serves on NASA Space Technology Mission Directorate’s Technology, Innovation and Engineering Committee. In 2014, and the University of Alabama at Birmingham formed the Alliance for Innovative Medical Technology (AIMTech) to develop new medical devices to improve healthcare. The creation of medical devices are across all five specializations: Cardiology, Orthopedics, Ophthalmology, Rehabilitation and Trauma. The goal is for the first group of AIMTech-created medical devices to hit the market by 2020. By comparison, it can take 10 years to create an FDA approved drug. In 2016, AIMTech was awarded a $500,000 U.S. Department of Commerce grant to expand medical device innovation and commercialization. | https://en.wikipedia.org/wiki?curid=23262740 |
Specific ion interaction theory Specific ion Interaction Theory (SIT theory) is a theory used to estimate single-ion activity coefficients in electrolyte solutions at relatively high concentrations. It does so by taking into consideration "interaction coefficients" between the various ions present in solution. Interaction coefficients are determined from equilibrium constant values obtained with solutions at various ionic strengths. The determination of SIT interaction coefficients also yields the value of the equilibrium constant at infinite dilution. The need for this theory arises from the need to derive activity coefficients of solutes when their concentrations are too high to be predicted accurately by Debye-Hückel theory. These activity coefficients are needed because an equilibrium constant is defined in thermodynamics as a quotient of activities but is usually measured using concentrations. The protonation of a monobasic acid will be used to simplify the exposition. The equilibrium for protonation of the conjugate base, A of the acid, may be written as for which where {HA} signifies an activity of the chemical species HA "etc.". The role of water in the equilibrium has been ignored as in all but the most concentrated solutions the activity of water is a constant. Note that "K" is defined here as an "association" constant, the reciprocal of an acid dissociation constant. Each activity term can be expressed as the product of a concentration and an activity coefficient | https://en.wikipedia.org/wiki?curid=23263587 |
Specific ion interaction theory For example, where the square brackets signify a concentration and γ is an activity coefficient. Thus the equilibrium constant can be expressed as a product of a concentration quotient and an activity coefficient quotient. Taking logarithms. "K" is the hypothetical value that the equilibrium constant would have if the solution of the acid were so dilute that the activity coefficients were all equal to one. It is common practise to determine equilibrium constants in solutions containing an electrolyte at high ionic strength such that the activity coefficients are effectively constant. However, when the ionic strength is changed the measured equilibrium constant will also change, so there is a need to estimate individual (single ion) activity coefficients. Debye-Huckel theory provides a means to do this, but it is accurate only at very low concentrations. Hence the need for an extension to Debye-Hückel theory. Two main approaches have been used. SIT theory, discussed here and Pitzer equations. SIT theory was first proposed by Brønsted and was further developed by Guggenheim. Scatchard extended the theory to allow the interaction coefficients to vary with ionic strength. The theory was mainly of theoretical interest until 1945 because of the difficulty of determining equilibrium constants before the glass electrode was invented. Subsequently, Ciavatta developed the theory further | https://en.wikipedia.org/wiki?curid=23263587 |
Specific ion interaction theory The activity coefficient of the "j"th ion in solution is written as γ when concentrations are on the molal concentration scale and as "y" when concentrations are on the molar concentration scale. (The molality scale is preferred in thermodynamics because molal concentrations are independent of temperature). The basic idea of SIT theory is that the activity coefficient can be expressed as or where "z" is the electrical charge on the ion, "I" is the ionic strength, ε and "b" are interaction coefficients and "m" and "c" are concentrations. The summation extends over the other ions present in solution, which includes the ions produced by the background electrolyte. The first term in these expressions comes from Debye-Hückel theory. The second term shows how the contributions from "interaction" are dependent on concentration. Thus, the interaction coefficients are used as corrections to Debye-Hückel theory when concentrations are higher than the region of validity of that theory. The activity coefficient of a neutral species can be assumed to depend linearly on ionic strength, as in where "k" is a Sechenov coefficient. In the example of a monobasic acid HA, assuming that the background electrolyte is the salt NaNO, the interaction coefficients will be for interaction between H and NO, and between A and Na. Firstly, equilibrium constants are determined at a number of different ionic strengths, at a chosen temperature and particular background electrolyte | https://en.wikipedia.org/wiki?curid=23263587 |
Specific ion interaction theory The interaction coefficients are then determined by fitting to the observed equilibrium constant values. The procedure also provides the value of "K" at infinite dilution. It is not limited to monobasic acids. and can also be applied to metal complexes. The SIT and Pitzer approaches have been compared recently. The Bromley equation has also been compared to both SIT and Pitzer equations. | https://en.wikipedia.org/wiki?curid=23263587 |
Dynamic structure factor In condensed matter physics, the dynamic structure factor (or dynamical structure factor) is a mathematical function that contains information about inter-particle correlations and their time evolution. It is a generalization of the structure factor that considers correlations in both space "and" time. Experimentally, it can be accessed most directly by inelastic neutron scattering or X-ray Raman scattering. The dynamic structure factor is most often denoted formula_1, where formula_2 (sometimes formula_3) is a wave vector (or wave number for isotropic materials), and formula_4 a frequency (sometimes stated as energy, formula_5). It is defined as: Here formula_7, is called the intermediate scattering function and can be measured by neutron spin echo spectroscopy. The intermediate scattering function is the spatial Fourier transform of the van Hove function formula_8: Thus we see that the dynamical structure factor is the spatial "and" temporal Fourier transform of van Hove's time-dependent pair correlation function. It can be shown (see below), that the intermediate scattering function is the correlation function of the Fourier components of the density formula_10: The dynamic structure is exactly what is probed in coherent inelastic neutron scattering. The differential cross section is : where formula_13 is the scattering length | https://en.wikipedia.org/wiki?curid=23264409 |
Dynamic structure factor The van Hove function for a spatially uniform system containing formula_14 point particles is defined as: It can be rewritten as: In an isotropic sample "G"("r","t") depends only on the distance "r" and is the time dependent radial distribution function. | https://en.wikipedia.org/wiki?curid=23264409 |
Optical transfection is the process of introducing nucleic acids into cells using light. Typically, a laser is focussed to a diffraction limited spot (~1 µm diameter) using a high numerical aperture microscope objective. The plasma membrane of a cell is then exposed to this highly focussed light for a small amount of time (typically tens of milliseconds to seconds), generating a transient pore on the membrane. The generation of a photopore allows exogenous plasmid DNA, RNA, organic fluorophores, or larger objects such as semiconductor quantum nanodots to enter the cell. In this technique, one cell at a time is treated, making it particularly useful for single cell analysis. To put the above simply, cells do not usually allow certain types of substances into their interior space. Lasers can be used to burn a tiny hole on the cell surface, allowing those substances to enter. This is tremendously useful to biologists who are studying disease, as a common experimental requirement is to put things (such as DNA) into cells. This technique was first demonstrated in 1984 by Tsukakoshi et al., who used a frequency tripled Nd:YAG to generate stable and transient transfection of normal rat kidney cells. Since this time, the optical transfection of a host of mammalian cell types has been demonstrated using a variety of laser sources, including the 405 nm continuous wave (cw), 488 nm cw, or pulsed sources such as the 800 nm femtosecond pulsed Ti:Sapphire or 1064 nm nanosecod pulsed Nd:YAG. The meaning of the term transfection has evolved | https://en.wikipedia.org/wiki?curid=23278041 |
Optical transfection The original meaning of transfection was "infection by transformation", "i.e." introduction of DNA (or RNA) from a prokaryote-infecting virus or bacteriophage into cells, resulting in an infection. Because the term transformation had another sense in animal cell biology (a genetic change allowing long-term propagation in culture, or acquisition of properties typical of cancer cells), the term transfection acquired, for animal cells, its present meaning of a change in cell properties caused by introduction of DNA (or other nucleic acid species such as RNA or SiRNA). Because of this strict definition of transfection, optical transfection also refers only to the introduction of nucleic acid species. The introduction of other impermeable compounds into a cell, such as organic fluorophores or semiconductor quantum nanodots is not strictly speaking "transfection," and is therefore referred to as "optical injection" or one of the other many terms now outlined. The lack of a unified name for this technology makes reviewing the literature on the subject very difficult. Optical injection has been described using over a dozen different names or phrases (see bulleted lists below). Some trends in the literature are clear. The first term of the technique is invariably a derivation of word laser, optical, or photo, and the second term is usually in reference to injection, transfection, poration, perforation or puncture | https://en.wikipedia.org/wiki?curid=23278041 |
Optical transfection Like many cellular perturbations, when a single cell or group of cells is treated with a laser, three things can happen: the cell dies (overdose), the cell membrane is permeabilised, substances enter, and the cell recovers (therapeutic dose), or nothing happens (underdose). There have been suggestions in the literature to reserve the term optoinjection for when a therapeutic dose is delivered upon a single cell, and the term optoporation for when a laser generated shockwave treats a cluster of many (10s to 100s) cells. The first definition of optoinjection is uncontroversial. The definition of optoporation, however, has failed to be adopted, with a similar number of references using the term to denote the dosing of single cells as those using the term to denote the simultaneous dosing of clusters of many cells As the field stands, it is the opinion of the authors of a review article on the subject that the term optoinjection always be included as a keyword in future publications, regardless of their own naming preferences. Terms agreed by consensus Terms under deliberation Some of the above was reproduced with permission from | https://en.wikipedia.org/wiki?curid=23278041 |
Optical transfection A typical optical transfection protocol is as follows: 1) Build an optical tweezers system with a high NA objective 2) Culture cells to 50-60% confluency 3) Expose cells to at least 10 µg/ml of plasmid DNA 4) Dose the plasma membrane of each cell with 10-40 ms of focussed laser, at a power of <100 mW at focus 5) Observe transient transfection 24-96h later 6) Add selective medium if the generation of stable colonies is desired | https://en.wikipedia.org/wiki?curid=23278041 |
Organoindium chemistry is the chemistry of compounds containing In-C bonds. The main application of organoindium chemistry is in the preparation of semiconducting components for microelectronic applications. The area is also of some interest in organic synthesis. Most organoindium compounds feature the In(III) oxidation state, akin to its lighter congeners Ga(III) and B(III). Monovalent In is relatively more common than Ga(I) or B(I). One example is cyclopentadienylindium(I). Trimethylindium is a colorless, volatile solid. It is the preferred source of indium for metalorganic vapour phase epitaxy (MOVPE) of indium-containing compound semiconductors, such as InP, InAs, AlInGaNP, etc. InMe is pyrophoric. To obtain the trialkyl derivatives, alkylation of indium trihalides with organolithium reagents is typical. OrganoIn(III) compounds are also prepared by treating In metal with alkyl halides. This reaction gives mixed organoindium halides. Illustrative is the reaction of allyl bromide with a THF suspension of indium. Both monoallylindium dibromide and diallylindium bromide are produced. A variety of organoindium(III) species such as InRX and solvates of RXIn, RIn, and XIn are thought to rapidly interconvert at room temperature | https://en.wikipedia.org/wiki?curid=23281496 |
Organoindium chemistry IMAs proceed in two steps: first, indium reacts with the allyl halide, give an allyl-In(III) intermediate, second, this allyl indide reacts with an electrophile: <br> <br> The reaction is conducted under the conditions of a Barbier reaction where the indium, allyl halide, and electrophile are all mixed in a one-pot process. Indium alkylates more readily than other metals, such as Mg, Pb, Bi, or Zn and does not require a promoter or organic solvent. IMAs have advantages over other carbon bond forming reactions because of their ability to be carried out in water (see Green chemistry). Although indium mediated allylations can be carried out in aqueous media, a variety of other solvents may be used including THF (tetrahydrofuran), DMF (dimethylformamide), room temperature ionic liquids, NMF (n-methylformamide), and others. Solvent often affects the solubility, rate of the reaction, yield, stability, regioselectivity, and stereoselectivity. Indium mediates the allylation of a wide variety of electrophiles. The examples in the following scheme illustrate the breadth of applications of IMA. Organoindium intermediates do not react with –OH or –COH groups. Reactions with carbonyls, however, give high yields. Research has shown that in reactions of an indium intermediate with an electrophilic compound of both aldehyde and ketone, the reaction proceeded with the aldehyde. The electrophilic compound is shown below | https://en.wikipedia.org/wiki?curid=23281496 |
Organoindium chemistry The regioselectivity of allylation mediated by indium in water is dependent on the steric effects of the substituents on both the intermediate and carbonyl. An α-attack from the nucleophile (at the position bearing the halogen) is distinguishable from a γ-attack (at the double bond) by inspecting the products. The scheme below gives an example of two different products formed from the same nucleophile under α-regioselectivity (α) and γ-regioselectivity (γ). This regioselectivity does not appear to depend on conjugation or the degree of substitution. The addition of allylindium reagents to aldehydes substituted at α or β carbons can be very diastereoselective in aqueous systems. For example, if chelation control is present in an α-oxy aldehyde, the product is expected to be the syn diastereomer. A sample reaction of chelation versus non-chelation control is illustrated below. Numerous investigations have found an explanation for this effect. The oxygens of the carbonyl and the hydroxyl group chelate the indium of the organoindium intermediate as illustrated below on the left by the two green bonds. The incipient C-C bond, illustrated in red, creates a six-member ring in a chair conformation. Under chelation control, the allyl group attacks the carbonyl carbon from the less hindered side opposite to that of the R group. Once the C-C bond is fully formed, the indium is released, producing the syn diol. A similar chelated structure is relevant to the allylation of β-oxy aldehydes results in anti diols | https://en.wikipedia.org/wiki?curid=23281496 |
Organoindium chemistry The addition of allylindium reagents to electrophilic hydrazones, illustrated below, has been reported to synthesize only one enantiomer of the chiral product with up to 97% selectivity using binol as a chiral additive. Similarly, a chiral amino alcohol allows for extremely high enantioselectivity in the allylation of ketones. | https://en.wikipedia.org/wiki?curid=23281496 |
List of molecular graphics systems This is a list of software systems that are used for visualizing macromolecules. The tables below indicate which types of data can be visualized in each system: | https://en.wikipedia.org/wiki?curid=23284727 |
Rubidium-82 (Rb) is a radioactive isotope of rubidium. Rb is widely used in myocardial perfusion imaging. This isotope undergoes rapid uptake by myocardiocytes, which makes it a valuable tool for identifying myocardial ischemia in Positron Emission Tomography (PET) imaging. Rb is used in the pharmaceutical industry and is marketed as chloride under the trade names RUBY-FILL and CardioGen-82. In 1953, it was discovered that rubidium carried a biological activity that was comparable to potassium. In 1959, preclinical trials showed in dogs that myocardial uptake of this radionuclide was directly proportional to myocardial blood flow. In 1979, Yano et al. compared several ion-exchange columns to be used in an automated Sr/Rb generator for clinical testing. Around 1980, pre-clinical trials began using Rb in PET. In 1982, Selwyn et al. examined the relation between myocardial perfusion and rubidium-82 uptake during acute ischemia in six dogs after coronary stenosis and in five volunteers and five patients with coronary artery disease. Myocardial tomograms, recorded at rest and after exercise in the volunteers showed homogeneous uptake in reproducible and repeatable scans. has shown considerable accuracy, comparable to that of Tc-SPECT. In 1989, the FDA approved the Rb/Sr generator for commercial use in the U.S. With increased Sr production capabilities, the use of Rb has increased over the last 10 years and is now approved by several health authorities worldwide | https://en.wikipedia.org/wiki?curid=23285206 |
Rubidium-82 is produced through beta plus decay from its parent nucleus, strontium-82. The generator contains accelerator produced Sr adsorbed on stannic oxide in a lead-shielded column and provides a means for obtaining sterile nonpyrogenic solutions of RbCl(Halide salt form capable of injection). The amount (millicuries) of Rb obtained in each elution will depend on the potency of the generator. When eluted at a rate of 50 mL/minute, each generator eluate at the end of elution should not contain more than 0.02 microcuries of strontium Sr and not more than 0.2 microcuries of Sr per millicurie of RbCl injection, and not more than 1 microgram of tin per mL of eluate. Rb has activity very similar to that of a potassium ion (K). Once in the myocardium, it is an active participant in the sodium-potassium exchange pump of cells. It is rapidly extracted by the myocardium proportional to blood flow. Its radioactivity is increased in viable myocardial cells reflecting cellular retention, while the tracer is cleared rapidly from necrotic or infarcted tissue. When tested clinically, Rb is seen in the myocardium within the first minute of intravenous injection. When the myocardium is affected with ischemia or infarction, they will be visualized between 2–7 minutes. These affected areas will be shown as photon deficient on the PET scan. Rb passes through the entire body on the first pass of circulation and has visible uptake in organs such as the kidney, liver, spleen and lung. This is due to the high vascularity of those organs | https://en.wikipedia.org/wiki?curid=23285206 |
Rubidium-82 Rubidium is rapidly extracted from the blood and is taken up by the myocardium in relation to myocardial perfusion, which requires energy for myocardial uptake through Na/K-ATPase similar to thallium-201. Rb is capable of producing a clear perfusion image similar to single photon emission computed tomography(SPECT)-MPI because it is an extractable tracer. The short half-life requires rapid image acquisition shortly after tracer administration, which reduces total study time. The short half-life also allows for less radiation experienced by the patient. A standard visual perfusion imaging assessment is based on defining regional uptake relative to the maximum uptake in the myocardium. Importantly, Rb PET also seems to provide prognostic value in patients who are obese and whose diagnosis remains uncertain after SPECT-MPI. Rb myocardial blood flow quantification is expected to improve the detection of multivessel coronary heart disease. Rb/PET is a valuable tool in ischemia identification. Myocardial Ischemia is an inadequate blood supply to the heart. Rb/PET can be used to quantify the myocardial flow reserve in the ventricles which then allows the medical professional to make an accurate diagnosis and prognosis of the patient. Various vasoreactivity studies are made possible through Rb/PET imaging due to its quantification of myocardial blood flow. It is possible to quantify stress in patients under the same reasoning | https://en.wikipedia.org/wiki?curid=23285206 |
Rubidium-82 Recently it has been shown that neuroendocrine tumor metastasis can be imaged with Rb due to its ability to quantify myocardial blood flow (MBF) during rest and pharmacological stress, commonly performed with adenosine. One of the main advantages of Rb is its availability in nuclear medicine departments. This isotope is available after 10-minute elution of a Sr column; this makes it possible to produce enough samples to inject about 10–15 patients a day. Another advantage of Rb would be its high count density in myocardial tissue. Rb/PET has shown greater uniformity and count density than Tc-SPECT when examining the myocardium. This results in higher interpretive confidence and greater accuracy. It allows for quantification of coronary flow reserve and myocardial blood flow. Rb also has an advantage in that it has a very short half-life which results in much lower radiation exposure for the patient. This is especially important as the use of myocardial imaging increases in the medical field. When it comes to patients, Rb is beneficial to use when the patient is obese or physically unable to perform a stress test. It also has side effects limited to minor irritation around the injection site. A serious limitation of Rb would be its cost. Currently Tc costs on average $70 per dose, needing two doses; whereas Rb costs about $250 a dose | https://en.wikipedia.org/wiki?curid=23285206 |
Rubidium-82 Another limitation of this isotope is that it needs a dedicated PET/CT camera, and in places like Europe where a Sr/Rb generator is still yet to be approved that can be hard to find. | https://en.wikipedia.org/wiki?curid=23285206 |
Levosulpiride Levosulpiride, sold under the Brand name Neoprad is a substituted benzamide antipsychotic, reported to be a selective antagonist of dopamine D receptor activity on both central and peripheral levels. It is an atypical neuroleptic and a prokinetic agent. is also claimed to have mood elevating properties. Chemically, it is the ("S")-(−)-enantiomer of sulpiride. is used in the treatment of: is not currently licensed for treatment of premature ejaculation in the UK or other European countries. Side effects include amenorrhea, gynecomastia, galactorrhea, changes in libido, and neuroleptic malignant syndrome. In the U.S., as of 2013 only one case of adverse reaction to had been recorded on the FDA Adverse Event Reporting System Database. A case of rapid onset resistant dystonia caused by low dose levosulpiride was reported in India. In contrast to most other neuroleptics which block both dopamine D and D receptors, sulpiride is more selective and acts primarily as a dopamine D antagonist. Sulpiride appears to lack effects on norepinephrine, acetylcholine, serotonin, histamine, or gamma-aminobutyric acid (GABA) receptors. Sulpiride is a substituted benzamide derivative and a selective dopamine D antagonist with antipsychotic and antidepressant activity. Other benzamide derivatives include metoclopramide, tiapride, and sultopride. | https://en.wikipedia.org/wiki?curid=23294687 |
Thallium oxide Thallium has several oxides: | https://en.wikipedia.org/wiki?curid=23298329 |
Cantera (software) Cantera is an open-source chemical kinetics software used for solving chemically reacting laminar flows. It has been used as a third-party library in external reacting flow simulation codes, such as FUEGO and CADS, using Fortran, C++, etc. to evaluate properties and chemical source terms that appear in the application's governing equations. Cantera was originally written and developed by Prof. Dave Goodwin of California Institute of Technology. It is written in C++ and can be used from C++, Python, Matlab and Fortran. | https://en.wikipedia.org/wiki?curid=23305579 |
List of microscopy visualization systems This is a list of software systems that are used for visualizing microscopy data. For each software system, the table below indicates which type of data can be displayed: EM = Electron microscopy; MG = Molecular graphics; Optical = Optical microscopy. | https://en.wikipedia.org/wiki?curid=23320406 |
Shawcor Ltd is a Canadian oilfield services company, based in Toronto, Ontario, and listed on the Toronto Stock Exchange. It specializes in providing services to the pipeline sector of the oil and gas market. It is one of the largest pipe-coating providers in the world. In 2017, it had a revenue of $1.56 billion. It was founded by Francis Shaw, the father of the founder of Shaw Communications, and there was substantial ownership in both companies by the Shaw family for many years. was founded in the mid-20th century by Francis Shaw in rural Lambton County. It was originally a construction company, but later expanded into pipeline coatings, cable television, and numerous other businesses. In the 1970s, the business was split between Francis's sons Leslie and JR Shaw; Leslie inherited the pipeline services business, which became the current Shawcor, while JR Shaw inherited the western cable business, which became Shaw Communications. Under Leslie's leadership, the company grew significantly; by 2002, it had a market capitalization of $1 billion, and 43 plants in 20 countries. Around that time, Leslie ceded his leadership of the business to his daughter, Virginia Shaw. In 2012, suggested that it might consider putting itself up for sale. At the time, the company had a market capitalization of about $3 billion. The company eventually decided not to sell, causing to share price to fall 15%. In 2013, it eliminated its dual class share structure, under which the Shaw family controlled the majority of voting shares | https://en.wikipedia.org/wiki?curid=23325548 |
Shawcor operates through 5 business units: Pipeline Performance (Bredero-Shaw, Socotherm, Canusa-CPS, Dhatec), Composite Production Systems (FlexPipe, Global Poly, FlexFlow, ZCL/Xerxes), Integrity Management (Shaw Pipeline Services, Inspection Services, Lake Superior Consulting), Oilfield Asset Management (Guardian, CSI), and Connection Systems (DSG-Canusa, Shawflex). It has about 100 manufacturing and service facilities and sales offices and 6000 employees in 25 countries. The pipe coating solutions division, which is the largest division in the company, was formerly part of Halliburton, an international oilfield services conglomerate. At that time, it was named Bredero Price. acquired the portion of the division it did not already own for $200 million in 2002. | https://en.wikipedia.org/wiki?curid=23325548 |
Wet sulfuric acid process The wet sulfuric acid process (WSA process) is one of the key gas desulfurization processes on the market today. Since the Danish catalyst company Haldor Topsoe introduced and patented this technology in the late 1980s, it has been recognised as an efficient process for recovering sulfur from various process gasses in the form of commercial quality sulfuric acid (HSO), with simultaneous production of high pressure steam. The WSA process is applied in all industries where removal of sulfur is an issue. The wet catalysis process is especially suited for processing one or more sulfur containing streams such as.: The energy released by the above-mentioned reactions is used for steam production. Approximately 2–3 ton high-pressure steam per ton of acid produced. Industries where WSA process plants are installed: The acid gas coming from a Rectisol-, Selexol-, amine gas treating or similar installed after the gasifier contains HS, COS and hydrocarbons in addition to CO. These gases were previously often flared and vented to the atmosphere, but now the acid gas requires purification in order not to affect the environment with SO emission. Not only can the WSA process meet the demands of SO removal, the process also accepts a wide range of feed-gas compositions. The WSA plant provides a high sulfur recovery and the heat recovered causes a substantial steam production. The heat recovery rate is high and the cooling water consumption low, resulting in superior cost performance of this process | https://en.wikipedia.org/wiki?curid=23338454 |
Wet sulfuric acid process Example 1: Example 2: A sulfur plant in China will be built in connection with an ammonia plant, producing 500 kilotons/annum of ammonia for fertilizer production The WSA process can also be used for production of sulfuric acid from sulfur burning or for regeneration of the spent acid from e.g. alkylation plants. Wet catalysis processes differ from other contact sulfuric acid processes in that the feed gas contains excess moisture when it comes into contact with the catalyst. The sulfur trioxide formed by catalytic oxidation of the sulfur dioxide reacts instantly with the moisture to produce sulfuric acid in the vapour phase to an extent determined by the temperature. Liquid acid is subsequently formed by condensation of the sulfuric acid vapour and not by absorption of the sulfur trioxide in concentrated sulfuric acid, as is the case in contact processes based on dry gases. The concentration of the product acid depends on the HO/SO ratio in the catalytically converted gases and on the condensation temperature. The combustion gases are cooled to the converter inlet temperature of about 420–440 °C. To process these wet gases in a conventional cold-gas contact process (DCDA) plant would necessitate cooling and drying of the gas to remove all moisture. Therefore, the WSA process is in many cases a more cost-efficient way of producing sulfuric acid. About 80% to 85% of the world’s sulfur production is used to manufacture sulfuric acid | https://en.wikipedia.org/wiki?curid=23338454 |
Wet sulfuric acid process 50% of the world’s sulfuric acid production is used in fertilizer production, mainly to convert phosphates to water-soluble forms, according to the Fertilizer Manual, published jointly by the United Nations Industrial Development Organization (UNIDO) and the International Fertilizer Development Center. | https://en.wikipedia.org/wiki?curid=23338454 |
Amasa Stone Bishop (1921 – May 21, 1997) was an American nuclear physicist specializing in fusion physics. He received his B.S. in Physics from the California Institute of Technology in 1943. From 1943 to 1946 he was a member of the staff of Radiation Laboratory at the Massachusetts Institute of Technology, where he was involved with radar research and development. Later, he became a staff member of the University of California at Berkeley from 1946 to 1950. Specializing in high energy particle work, he earned his Ph.D. in Physics in 1950. After attaining his Ph.D., Amasa spent three years in Switzerland, acting as Research Associate at the Federal Institute of Technology in Zürich, and later at the University of Zürich. In 1953 Amasa joined the research division of the Atomic Energy Commission (AEC) in Washington and became the director of the American program to develop controlled fusion, also known as Project Sherwood. He was later presented the AEC Outstanding Service Award for his work. After leaving this position in 1956, Amasa published a book on behalf of the AEC discussing the various attempts at harnessing fusion under Project Sherwood. The book, "Project Sherwood: The U.S. Program in Controlled Fusion", was published in 1958. After 1956 Amasa also served as the AEC's European scientific representative, based in Paris. He was also an assistant delegate to the European atomic energy agency, Euratom, in Brussels. Later he spent several years in Princeton, New Jersey, and was in charge of the fusion program in Washington | https://en.wikipedia.org/wiki?curid=23348207 |
Amasa Stone Bishop In 1970 Amasa joined the United Nations in Europe as director of environment of the United Nations Economic Commission for Europe. During this position he worked with scientists and diplomats to create solutions for various environmental problems. He left this position to retire in 1980. Amasa died on May 21, 1997, of pneumonia related to Alzheimer's disease at the Clinique de Genolier in Genolier, Switzerland. | https://en.wikipedia.org/wiki?curid=23348207 |
Flux pumping is a method for magnetising superconductors to fields in excess of 15 teslas. The method can be applied to any type II superconductor and exploits a fundamental property of superconductors. That is their ability to support and maintain currents on the length scale of the superconductor. Conventional magnetic materials are magnetised on a molecular scale which means that superconductors can maintain a flux density orders of magnitude bigger than conventional materials. is especially significant when one bears in mind that all other methods of magnetising superconductors require application of a magnetic flux density at least as high as the final required field. This is not true of flux pumping. An electric current flowing in a loop of superconducting wire can persist indefinitely with no power source. In a normal conductor, an electric current may be visualized as a fluid of electrons moving across a heavy ionic lattice. The electrons are constantly colliding with the ions in the lattice, and during each collision some of the energy carried by the current is absorbed by the lattice and converted into heat, which is essentially the vibrational kinetic energy of the lattice ions. As a result, the energy carried by the current is constantly being dissipated. This is the phenomenon of electrical resistance. The situation is different in a superconductor. In a conventional superconductor, the electronic fluid cannot be resolved into individual electrons | https://en.wikipedia.org/wiki?curid=23355682 |
Flux pumping Instead, it consists of bound "pairs" of electrons known as Cooper pairs. This pairing is caused by an attractive force between electrons from the exchange of phonons. Due to quantum mechanics, the energy spectrum of this Cooper pair fluid possesses an "energy gap", meaning there is a minimum amount of energy Δ"E" that must be supplied in order to excite the fluid. Therefore, if Δ"E" is larger than the thermal energy of the lattice, given by "kT", where "k" is Boltzmann's constant and "T" is the temperature, the fluid will not be scattered by the lattice. The Cooper pair fluid is thus a superfluid, meaning it can flow without energy dissipation. In a class of superconductors known as type II superconductors, including all known high-temperature superconductors, an extremely small amount of resistivity appears at temperatures not too far below the nominal superconducting transition when an electric current is applied in conjunction with a strong magnetic field, which may be caused by the electric current. This is due to the motion of vortices in the electronic superfluid, which dissipates some of the energy carried by the current. If the current is sufficiently small, then the vortices are stationary, and the resistivity vanishes. The resistance due to this effect is tiny compared with that of non-superconducting materials, but must be taken into account in sensitive experiments. In the method described here a magnetic field is swept across the superconductor in a magnetic wave | https://en.wikipedia.org/wiki?curid=23355682 |
Flux pumping This field induces current according to Faraday's law of induction. As long as the direction of motion of the magnetic wave is constant then the current induced will always be in the same sense and successive waves will induce more and more current. Traditionally the magnetic wave would be generated either by physically moving a magnet or by an arrangement of coils switched in sequence, such as occurs on the stator of a three-phase motor. Flux Pumping is a solid state method where a material which changes magnetic state at a suitable magnetic ordering temperature is heated at its edge and the resultant thermal wave produces a magnetic wave which then magnetizes the superconductor. A superconducting flux pump should not be confused with a classical flux pump as described in Van Klundert et al.’s review. The method described here has two unique features: The system, as described, is actually a novel kind of heat engine in which thermal energy is being converted into magnetic energy. When a superconductor is placed in a weak external magnetic field H, the field penetrates the superconductor only a small distance "λ", called the London penetration depth, decaying exponentially to zero within the interior of the material. This is called the Meissner effect, and is a defining characteristic of superconductivity. For most superconductors, the London penetration depth is on the order of 100 nm | https://en.wikipedia.org/wiki?curid=23355682 |
Flux pumping The Meissner effect is sometimes confused with the kind of diamagnetism one would expect in a perfect electrical conductor: according to Lenz's law, when a "changing" magnetic field is applied to a conductor, it will induce an electric current in the conductor that creates an opposing magnetic field. In a perfect conductor, an arbitrarily large current can be induced, and the resulting magnetic field exactly cancels the applied field. The Meissner effect is distinct from this because a superconductor expels "all" magnetic fields, not just those that are changing. Suppose we have a material in its normal state, containing a constant internal magnetic field. When the material is cooled below the critical temperature, we would observe the abrupt expulsion of the internal magnetic field, which we would not expect based on Lenz's law. The Meissner effect was explained by the brothers Fritz and Heinz London, who showed that the electromagnetic free energy in a superconductor is minimized provided where H is the magnetic field and λ is the London penetration depth. This equation, which is known as the London equation, predicts that the magnetic field in a superconductor decays exponentially from whatever value it possesses at the surface. In 1962, the first commercial superconducting wire, a niobium-titanium alloy, was developed by researchers at Westinghouse, allowing the construction of the first practical superconducting magnets | https://en.wikipedia.org/wiki?curid=23355682 |
Flux pumping In the same year, Josephson made the important theoretical prediction that a supercurrent can flow between two pieces of superconductor separated by a thin layer of insulator. This phenomenon, now called the Josephson effect, is exploited by superconducting devices such as SQUIDs. It is used in the most accurate available measurements of the magnetic flux quantum formula_2, and thus (coupled with the quantum Hall resistivity) for Planck's constant "h". Josephson was awarded the Nobel Prize for this work in 1973. The most popular model used to describe superconductivity is the Bean or Critical State model and variations such as the Kim-Anderson model. However the Bean model assumes zero resistivity and that current is always induced at the critical current. A more useful model for engineering applications is the so-called E-J power law in which the field and the current are linked by the following equations: In these equations if n = 1 then the conductor has linear resistivity such as is found in copper. The higher the n-value the closer we get to the critical state model. Also the higher the n-value then the "better" the superconductor as the lower the resistivity at a certain current. The E-J power law can be used to describe the phenomenon of flux-creep in which a superconductor gradually loses its magnetisation over time. This process is logarithmic and thus gets slower and slower and ultimately leads to very stable fields | https://en.wikipedia.org/wiki?curid=23355682 |
Flux pumping The potential of superconducting coils and bulk melt-processed YBCO single domains to maintain significant magnetic fields at cryogenic temperatures makes them particularly attractive for a variety of engineering applications including superconducting magnets, magnetic bearings and motors. It has already been shown that large fields can be obtained in single domain bulk samples at 77 K. A range of possible applications exist in the design of high power density electric motors. Before such devices can be created a major problem needs to be overcome. Even though all of these devices use a superconductor in the role of a permanent magnet and even though the superconductor can trap potentially huge magnetic fields (greater than 10 T) the problem is the induction of the magnetic fields, this applies both to bulk and to coils operating in persistent mode. There are four possible known methods: Any of these methods could be used to magnetise the superconductor and this may be done either in situ or ex situ. Ideally the superconductors are magnetised in situ. There are several reasons for this: first, if the superconductors should become demagnetised through (i) flux creep, (ii) repeatedly applied perpendicular fields or (iii) by loss of cooling then they may be re-magnetized without the need to disassemble the machine. Secondly, there are difficulties with handling very strongly magnetized material at cryogenic temperatures when assembling the machine | https://en.wikipedia.org/wiki?curid=23355682 |
Flux pumping Thirdly, ex situ methods would require the machine to be assembled both cold and pre-magnetized and would offer significant design difficulties. Until room temperature superconductors can be prepared, the most efficient design of machine will therefore be one in which an in situ magnetizing fixture is included! The first three methods all require a solenoid which can be switched on and off. In the first method an applied magnetic field is required equal to the required magnetic field, whilst the second and third approaches require fields at least two times greater. The final method, however, offers significant advantages since it achieves the final required field by repeated applications of a small field and can utilise a permanent magnet. If we wish to pulse a field using, say, a 10 T magnet to magnetize a 30 mm × 10 mm sample then we can work out how big the solenoid needs to be. If it were possible to wind an appropriate coil using YBCO tape then, assuming an I of 70 A and a thickness of 100 μm, we would have 100 turns and 7 000 A turns. This would produce a B field of approximately 7 000/(20 × 10) × 4π × 10 = 0.4 T. To produce 10 T would require pulsing to 1 400 A! An alternative calculation would be to assume a J of say 5 × 10Am and a coil 1 cm in cross section. The field would then be 5 × 10 × 10 × (2 × 4π × 10) = 10 T | https://en.wikipedia.org/wiki?curid=23355682 |
Flux pumping Clearly if the magnetisation fixture is not to occupy more room than the puck itself then a very high activation current would be required and either constraint makes in situ magnetization a very difficult proposition. What is required for in situ magnetisation is a magnetisation method in which a relatively small field of the order of milliteslas repeatedly applied is used to magnetize the superconductor. Superconducting magnets are some of the most powerful electromagnets known. They are used in MRI and NMR machines, mass spectrometers, Magnetohydrodynamic Power Generation and beam-steering magnets used in particle accelerators. They can also be used for magnetic separation, where weakly magnetic particles are extracted from a background of less or non-magnetic particles, as in the pigment industries. Other early markets are arising where the relative efficiency, size and weight advantages of devices based on HTS outweigh the additional costs involved. Promising future applications include high-performance transformers, power storage devices, electric power transmission, electric motors (e.g. for vehicle propulsion, as in vactrains or maglev trains), magnetic levitation devices, and fault current limiters. | https://en.wikipedia.org/wiki?curid=23355682 |
The Salters School of Chemistry is a branch of Christ's Hospital that teaches mainly chemistry to all Christ's Hospital pupils. It was founded by Samuel Porter and the Worshipful Company of Salters (one of the livery company that sponsors children to study at CH) in 1993. It is currently Christ's Hospital's Chemistry Department. | https://en.wikipedia.org/wiki?curid=23368656 |
Deflagration to detonation transition (DDT) refers to a phenomenon in ignitable mixtures of a flammable gas and air (or oxygen) when a sudden transition takes place from a deflagration type of combustion to a detonation type of explosion. A deflagration is characterized by a subsonic flame propagation velocity, typically far below , and relatively modest overpressures, say below . The main mechanism of combustion propagation is of a flame front that moves forward through the gas mixture - in technical terms the reaction zone (chemical combustion) progresses through the medium by processes of diffusion of heat and mass. In its most benign form, a deflagration may simply be a flash fire. In contrast, a detonation is characterized by supersonic flame propagation velocities, perhaps up to , and substantial overpressures, up to . The main mechanism of detonation propagation is of a powerful pressure wave that compresses the unburnt gas ahead of the wave to a temperature above the autoignition temperature. In technical terms, the reaction zone (chemical combustion) is a self-driven shock wave where the reaction zone and the shock are coincident, and the chemical reaction is initiated by the compressive heating caused by the shock wave. The process is similar to ignition in a Diesel engine, but much more sudden and violent | https://en.wikipedia.org/wiki?curid=23375296 |
Deflagration to detonation transition Under certain conditions, mainly in terms of geometrical conditions (such as partial confinement and many obstacles in the flame path that cause turbulent flame eddy currents), a subsonic flame may accelerate to supersonic speed, transitioning from deflagration to detonation. The exact mechanism is not fully understood, and while existing theories are able to explain and model both deflagrations and detonations, there is no theory at present which can predict the transition phenomenon. A deflagration to detonation transition has been a feature of several major industrial accidents: The phenomenon is exploited in pulse detonation engines, because a detonation produces a more efficient combustion of the reactants than a deflagration does, i.e. giving a higher yields. Such engines typically employ a Shchelkin spiral in the combustion chamber to facilitate the deflagration to detonation transition. The mechanism has also found military use in thermobaric weapons. An analogous deflagration to detonation transition (DDT) has also been proposed for thermonuclear reactions responsible for supernovae initiation. This process has been called a "carbon detonation". | https://en.wikipedia.org/wiki?curid=23375296 |
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