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He has authorised many articles and also served as keynote speakers at several local and international conferences. His work on nuclear chemistry includes the use of Cryogenically Produced Heavy Cluster ions of Hydrogen in the Study of Plasma Desorption Mass Spectrometry, as well as the establishment of a fully Automated AAS Laboratory with Graphite Atomization and Cold Vapor Hg Detection Option. | 0 | Theoretical and Fundamental Chemistry |
Recently it was pointed out that, in the same way that electric polarisation can be generated by spatially varying magnetic order, magnetism can be generated by a temporally varying polarisation. The resulting phenomenon was called Dynamical Multiferroicity. The magnetisation, is given by
where is the polarisation and the indicates the vector product. The dynamical multiferroicity formalism underlies the following diverse range of phenomena:
* The phonon Zeeman effect, in which phonons of opposite circular polarisation have different energies in a magnetic field. This phenomenon awaits experimental verification.
* Resonant magnon excitation by optical driven phonons.
* Dzylaoshinskii-Moriya-type electromagnons.
* The inverse Faraday effect.
* Exotic flavours of quantum criticality. | 0 | Theoretical and Fundamental Chemistry |
Proteins were recognized as a distinct class of biological molecules in the eighteenth century by Antoine Fourcroy and others. Members of this class (called the "albuminoids", Eiweisskörper, or matières albuminoides) were recognized by their ability to coagulate or flocculate under various treatments such as heat or acid; well-known examples at the start of the nineteenth century included albumen from egg whites, blood serum albumin, fibrin, and wheat gluten. The similarity between the cooking of egg whites and the curdling of milk was recognized even in ancient times; for example, the name albumen for the egg-white protein was coined by Pliny the Elder from the Latin albus ovi (egg white).
With the advice of Jöns Jakob Berzelius, the Dutch chemist Gerhardus Johannes Mulder carried out elemental analyses of common animal and plant proteins. To everyones surprise, all proteins had nearly the same empirical formula, roughly CHNO with individual sulfur and phosphorus atoms. Mulder published his findings in two papers (1837,1838) and hypothesized that there was one basic substance (Grundstoff') of proteins, and that it was synthesized by plants and absorbed from them by animals in digestion. Berzelius was an early proponent of this theory and proposed the name "protein" for this substance in a letter dated 10 July 1838
Mulder went on to identify the products of protein degradation such as the amino acid, leucine, for which he found a (nearly correct) molecular weight of 131 Da. | 1 | Applied and Interdisciplinary Chemistry |
Plant disease resistance is crucial to the reliable production of food, and it provides significant reductions in agricultural use of land, water, fuel and other inputs. Plants in both natural and cultivated populations carry inherent disease resistance, but this has not always protected them.
The late blight Great Famine of Ireland of the 1840s was caused by the oomycete Phytophthora infestans. The worlds first mass-cultivated banana cultivar Gros Michel was lost in the 1920s to Panama disease caused by the fungus Fusarium oxysporum. The current wheat stem rust, leaf rust and yellow stripe rust epidemics spreading from East Africa into the Indian subcontinent are caused by rust fungi Puccinia graminis and P. striiformis'. Other epidemics include chestnut blight, as well as recurrent severe plant diseases such as rice blast, soybean cyst nematode, and citrus canker.
Plant pathogens can spread rapidly over great distances, vectored by water, wind, insects, and humans. Across large regions and many crop species, it is estimated that diseases typically reduce plant yields by 10% every year in more developed nations or agricultural systems, but yield loss to diseases often exceeds 20% in less developed settings.
However, disease control is reasonably successful for most crops. Disease control is achieved by use of plants that have been bred for good resistance to many diseases, and by plant cultivation approaches such as crop rotation, pathogen-free seed, appropriate planting date and plant density, control of field moisture, and pesticide use. | 1 | Applied and Interdisciplinary Chemistry |
Groundwater and drinking water contamination from industrial discharge including trichloroethylene is a major concern for human health and has precipitated numerous incidents and lawsuits in the United States.
The 1995 non-fiction book A Civil Action was written about a lawsuit (Anderson v. Cryovac) against following the increase in cancer cases after trichloroethylene pollution incidents and it was adapted to cinema in 1998.
TCE has been used as a recreational drug. Common methods of taking trichloroethylene recreationally include inhalation from a rag (similar to taking an inhalational anaesthetic) and drinking. Most TCE abusers were young people and workers who use the chemical in their workplace. The main reason for abuse is TCE's euphoriant and slight hallucinogenic effect. Some workers had become addicted to TCE. | 1 | Applied and Interdisciplinary Chemistry |
The Jackson Laboratory in Bar Harbor, Maine, USA with the University of Southampton, UK identified ALMS1 as the single gene responsible for Alström syndrome. | 1 | Applied and Interdisciplinary Chemistry |
After synthesizing and purifying the core, the carbohydrate layer is added to its surface. Common coating materials are typically polyhydroxy oligomers such as cellobiose, citrate, lactose, and sucrose. This layer seems to be important for the properties of aquasomes, as it influences several drug characteristics including adsorption, molecular stability, and conformation, and acts as a dehydroprotectant. The addition of the carbohydrate layer to the surface of the nanocrystalline core is commonly carried out by passive adsorption through incubation and sonication. Similar to the processing of the core, the carbohydrate layer is subjected to centrifugation, washing, and further sonification followed by heated air drying. | 0 | Theoretical and Fundamental Chemistry |
Seafloor spreading on mid-ocean ridges is a global scale ion-exchange system. Hydrothermal vents at spreading centers introduce various amounts of iron, sulfur, manganese, silicon and other elements into the ocean, some of which are recycled into the ocean crust. Helium-3, an isotope that accompanies volcanism from the mantle, is emitted by hydrothermal vents and can be detected in plumes within the ocean.
Spreading rates on mid-ocean ridges vary between 10 and 200 mm/yr. Rapid spreading rates cause increased basalt reactions with seawater. The magnesium/calcium ratio will be lower because more magnesium ions are being removed from seawater and consumed by the rock, and more calcium ions are being removed from the rock and released to seawater. Hydrothermal activity at ridge crest is efficient in removing magnesium. A lower Mg/Ca ratio favors the precipitation of low-Mg calcite polymorphs of calcium carbonate (calcite seas).
Slow spreading at mid-ocean ridges has the opposite effect and will result in a higher Mg/Ca ratio favoring the precipitation of aragonite and high-Mg calcite polymorphs of calcium carbonate (aragonite seas).
Experiments show that most modern high-Mg calcite organisms would have been low-Mg calcite in past calcite seas, meaning that the Mg/Ca ratio in an organism's skeleton varies with the Mg/Ca ratio of the seawater in which it was grown.
The mineralogy of reef-building and sediment-producing organisms is thus regulated by chemical reactions occurring along the mid-ocean ridge, the rate of which is controlled by the rate of sea-floor spreading. | 0 | Theoretical and Fundamental Chemistry |
The oldest known example of applying the lost-wax technique to copper casting comes from a 6,000-year-old () copper, wheel-shaped amulet found at Mehrgarh, Pakistan.
Metal casting, by the Indus Valley civilization, produced some of the earliest known examples of lost-wax casting applied to the casting of copper alloys, a bronze figurine, found at Mohenjo-daro, and named the "dancing girl", is dated to 2300-1750 . Other examples include the buffalo, bull and dog found at Mohenjodaro and Harappa, two copper figures found at the Harappan site Lothal in the district of Ahmedabad of Gujarat, and likely a covered cart with wheels missing and a complete cart with a driver found at Chanhudaro.
During the post-Harappan period, hoards of copper and bronze implements made by the lost-wax process are known from Tamil Nadu, Uttar Pradesh, Bihar, Madhya Pradesh, Odisha, Andhra Pradesh and West Bengal. Gold and copper ornaments, apparently Hellenistic in style, made by cire perdue were found at the ruins at Sirkap. One example of this Indo-Greek art dates to the the juvenile figure of Harpocrates excavated at Taxila. Bronze icons were produced during the 3rd and 4th centuries, such as the Buddha image at Amaravati, and the images of Rama and Kartikeya in the Guntur district of Andhra Pradesh. A further two bronze images of Parsvanatha and a small hollow-cast bull came from Sahribahlol, Gandhara, and a standing Tirthankara () from Chausa in Bihar should be mentioned here as well. Other notable bronze figures and images have been found in Rupar, Mathura (in Uttar Pradesh) and Brahmapura, Maharashtra.
Gupta and post-Gupta period bronze figures have been recovered from the following sites: Saranath, Mirpur-Khas (in Pakistan), Sirpur (District of Raipur), Balaighat (near Mahasthan now in Bangladesh), Akota (near Vadodara, Gujarat), Vasantagadh, Chhatarhi, Barmer and Chambi (in Rajesthan). The bronze casting technique and making of bronze images of traditional icons reached a high stage of development in South India during the medieval period. Although bronze images were modelled and cast during the Pallava Period in the eighth and ninth centuries, some of the most beautiful and exquisite statues were produced during the Chola Period in Tamil Nadu from the tenth to the twelfth century. The technique and art of fashioning bronze images is still skillfully practised in South India, particularly in Kumbakonam. The distinguished patron during the tenth century was the widowed Chola queen, Sembiyan Maha Devi. Chola bronzes are the most soughtafter collectors’ items by art lovers all over the [https://ncert.nic.in/textbook/pdf/kefa107.pdf world]. The technique was used throughout India, as well as in the neighbouring countries Nepal, Tibet, Ceylon, Burma and Siam. | 1 | Applied and Interdisciplinary Chemistry |
The DNA molecule of interest must be incorporated into a hairpin, and attached to a magnetic bead on one end and to an immobile glass surface on the other end. The hairpin is attached to the glass surface via a digoxigenin-antidigoxigenin bond. The magnetic bead is attached to the opposite end via biotin-streptavidin interaction. Such DNA hairpin setup can be made in two ways:
:1) In the case of double-stranded DNA molecules (for whole genome sequencing, or targeted sequencing), the DNA fragment is ligated to a DNA loop at one end and a DNA fork structure, labeled with biotin and digoxigenin at the two ends.
:2) For RNA-seq, the mRNA can be trapped on a poly-T-coated bead, where reverse transcription reaction is performed on the bead to generate a cDNA hairpin. | 1 | Applied and Interdisciplinary Chemistry |
Orthoesters of diarylstibinic acids are fungicides and bactericides, used in paints, plastics, and fibers. Trivalent organic antimony was used in therapy for schistosomiasis. | 1 | Applied and Interdisciplinary Chemistry |
Eicosapentaenoic acid (EPA), the active metabolite of ethyl eicosapentaenoic acid (E-EPA), like other omega-3 fatty acid based drugs, appears to reduce production of triglycerides in the liver and to enhance clearance of triglycerides from circulating very low-density lipoprotein (VLDL) particles. The way it does that is not clear, but potential mechanisms include increased breakdown of fatty acids; inhibition of diglyceride acyltransferase, which is involved in biosynthesis of triglycerides in the liver; and increased activity of lipoprotein lipase in blood. | 1 | Applied and Interdisciplinary Chemistry |
Several drug or drug candidates feature amidine substituents. Examples include the antiprotozoal Imidocarb, the insecticide amitraz , the anthelmintic tribendimidine, and xylamidine, an antagonist at the 5HT2A receptor.
Formamidinium (see below) may be reacted with a metal halide to form the light-absorbing semiconducting material in perovskite solar cells. Formamidinium (FA) cations or halides may partially or fully replace methylammonium halides in forming perovskite absorber layers in photovoltaic devices. | 0 | Theoretical and Fundamental Chemistry |
Charles Wood was the 7th of 15 children of William Wood of Wolverhampton and his wife Margaret, daughter of Richard Molyneux, an ironmonger in that area. William Wood followed his father-in-law's trade until 1715, when he became an ironmaster too and later entered into a contract to provide copper coinage for Ireland. He was also a projector, floating his business as an ironmaster as a joint stock company at the time of the South Sea Bubble (1720). Later, he sought to develop a new process of ironmaking and to obtain a charter for a "Company of Ironmasters of Great Britain". However the process (carried on at Frizington, Cumberland) produced little iron and he probably died in debt. | 1 | Applied and Interdisciplinary Chemistry |
* One application for such a device is measuring the water content of soil, where the volume of water in the total volume of soil most heavily influences the dielectric permittivity of the soil because the dielectric of water (80) is much greater than the other constituents of the soil (mineral soil: 4, organic matter: 4, air: 1). When the amount of water changes in the soil, a probe will measure a change in capacitance due to the change in dielectric permittivity that can be directly correlated with a change in water content. Capacitance sensors are now widely used in irrigation scheduling in agriculture around the world.
* Cure monitoring of Composite materials: Dielectric or capacitance sensors are used to measure the electrical response of thermoset resins and matrices of composite materials at specified depth over the sensor surface. The key model involved in the use of these sensors is the electric field model. The correspondence between electrical properties of the material within the field and the measurement (i.e. capacitance) is fundamental in interpreting the readings from the dielectric sensor.
* Tip clearance measurement in turbomachinery testing.
* The capacitance-sensors also can be used for the measuring of level of some solid materials in structures such as hoppers or silos. | 0 | Theoretical and Fundamental Chemistry |
The overall success of OE-PCR based DNA assemblies relies on several factors, being the most relevant ones the instrinsic features of the DNA sequence to assemble, the sequence and length of the overlapping overhangs, the design of outer primers for the final amplification and the conditions of the PCR reaction. Normally, from 2 to 6 fragments can be spliced simultaneously into a single OE-PCR reaction. Overhangs should be at least 40 nucleotides long to ensure adequate interaction between fragments. Final amplification primers are commonly designed following general guidelines for PCR, however they are used in 2 to 5 times lower concentration than in standard PCR reactions, as it this has been shown to reduce undesired amplifications. Additionally the utilization of proofreading DNA polymerases is highly recommended. | 1 | Applied and Interdisciplinary Chemistry |
An antiphase domain (APD) is a type of planar crystallographic defect in which the atoms within a region of a crystal are configured in the opposite order to those in the perfect lattice system. Throughout the entire APD, atoms sit on the sites typically occupied by atoms of a different species. For example, in an ordered AB alloy, if an A atom occupies the site usually occupied by a B atom, a type of crystallographic point defect called an antisite defect is formed. If an entire region of the crystal is translated such that every atom in a region of the plane of atoms sits on its antisite, an antiphase domain is formed. In other words, an APD is a region formed from antisite defects of a parent lattice. On either side of this domain, the lattice is still perfect, and the boundaries of the domain are referred to as antiphase boundaries. Crucially, crystals on either side of an antiphase boundary are related by a translation, rather than a reflection (a crystal twin) or an inversion (an inversion domain). | 0 | Theoretical and Fundamental Chemistry |
The Günther Laukien Prize is a prize presented at the Experimental Nuclear Magnetic Resonance Conference "to recognize recent cutting-edge experimental NMR research with a high probability of enabling beneficial new applications". The prize was established in 1999 in memoriam to Günther Laukien, who was a pioneer in NMR research. The prize money of $20,000 is financed by Bruker, the company founded by Laukien. The recipients of the Günther Laukien Prize have been:
* 2023 Lyndon Emsley and Anne Lesage
* 2022 Michael Garwood
* 2021 Gareth Morris
* 2020 Simon Duckett, Konstantin Ivanov, and Warren S. Warren
* 2019 Geoffrey Bodenhausen, and Christian Griesinger
* 2018 Gerhard Wagner
* 2017 Kurt Zilm and Bernd Reif
* 2016 Robert S. Balaban and Peter van Zijl
* 2015 Arthur Palmer III
* 2014 Marc Baldus, Mei Hong, Ann McDermott, Beat H. Meier, Hartmut Oschkinat, and Robert Tycko
* 2013 Clare Grey
* 2012 Klaes Golman and Jan Henrik Ardenkjaer-Larsen
* 2011 Daniel Rugar, John Mamin, and John Sidles
* 2010 Paul Callaghan
* 2009 Daniel Weitekamp
* 2008 Malcolm Levitt
* 2007 Robert G. Griffin
* 2006 Thomas Szyperski, Eriks Kupce, Ray Freeman, and Rafael Bruschweiler
* 2005 Stephan Grzesiek
* 2004 Lewis E. Kay
* 2003 Jacob Schaefer
* 2002 Ad Bax, Aksel Bothner-By and James Prestegard
* 2001 Peter Boesiger, Klaas Prüßmann and Markus Weiger
* 2000 Lucio Frydman
* 1999 Konstantin Pervushin, Roland Riek, Gerhard Wider, and Kurt Wuthrich | 0 | Theoretical and Fundamental Chemistry |
In organometallic chemistry, a "constrained geometry complex" (CGC) is a kind of catalyst used for the production of polyolefins such as polyethylene and polypropylene. The catalyst was one of the first major departures from metallocene-based catalysts and ushered in much innovation in the development of new plastics. | 0 | Theoretical and Fundamental Chemistry |
Rotavirus translation, the process of translating mRNA into proteins, occurs in a different way in Rotaviruses. Unlike the vast majority of cellular proteins in other organisms, in Rotaviruses the proteins are translated from capped but nonpolyadenylated mRNAs. The viral nonstructural protein NSP3 specifically binds the 3-end consensus sequence of viral mRNAs and interacts with the eukaryotic translation initiation factor eIF4G. The Rotavirus replication cycle occurs entirely in the cytoplasm. Upon virus entry, the viral transcriptase synthesizes capped but nonpolyadenylated mRNA The viral mRNAs bear 5 and 3' untranslated regions (UTR) of variable length and are flanked by two different sequences common to all genes.
In the group A rotaviruses, the 3-end consensus sequence UGACC is highly conserved among the 11 genes. Rotavirus NSP3 presents several similarities to PABP; in rotavirus-infected cells, NSP3 can be cross-linked to the 3 end of rotavirus mRNAs and is coimmunoprecipitated with eIF4G. The binding of NSP3A to eIF4G and its specific interaction with the 3' end of viral mRNA brings the viral mRNA and the translation initiation machinery into contact, thus favoring efficient translation of the viral mRNA. NSP3 interacts with the same region of eIF4G as PABP does. As a consequence, during rotavirus infection PABP is evicted from eIF4G, probably impairing the translation of polyadenylated mRNA and leading to the shutoff of cellular mRNA translation observed during rotavirus infection. | 1 | Applied and Interdisciplinary Chemistry |
Like a droplet, bubbles are round because cohesive forces pull its molecules into the tightest possible grouping, a sphere. Due to the trapped air inside the bubble, it is impossible for the surface area to shrink to zero, hence the pressure inside the bubble is greater than outside, because if the pressures were equal, then the bubble would simply collapse. This pressure difference can be calculated from Laplace's pressure equation,
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For a soap bubble, there exists two boundary surfaces, internal and external, and therefore two contributions to the excess pressure and Laplace's formula doubles to
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The capillary length can then be worked out the same way except that the thickness of the film, must be taken into account as the bubble has a hollow center, unlike the droplet which is a solid. Instead of thinking of a droplet where each side is as in the above derivation, for a bubble is now
with and the radius and thickness of the bubble respectively.
As above, the Laplace and hydrostatic pressure are equated resulting in
Thus the capillary length contributes to a physiochemical limit that dictates the maximum size a soap bubble can take. | 1 | Applied and Interdisciplinary Chemistry |
Generally, two major frictional systems affect adhesive wear or galling: solid surface contact and lubricated contact. In terms of prevention, they work in dissimilar ways and set different demands on the surface structure, alloys, and crystal matrix used in the materials.
In solid surface contact or unlubricated conditions, the initial contact is characterized by the interaction between asperities and the exhibition of two different sorts of attraction: cohesive surface-energy or the molecules connect and adhere the two surfaces together, notably even if a measurable distance separates them. Direct contact and plastic deformation generate another type of attraction through the constitution of a plastic zone with flowing material where induced energy, pressure, and temperature allow bonding between the surfaces on a much larger scale than cohesive surface energy.
In metallic compounds and sheet metal forming, the asperities are usually oxides, and the plastic deformation primarily consists of brittle fracture, which presupposes a very small plastic zone. The accumulation of energy and temperature is low due to the discontinuity in the fracture mechanism.
However, during the initial asperity/asperity contact, wear debris or bits and pieces from the asperities adhere to the opposing surface, creating microscopic, usually localized, roughening and creation of protrusions (in effect lumps) above the original surface. The transferred wear debris and lumps penetrate the opposing oxide surface layer and cause damage to the underlying bulk material, plowing it forward. This allows continuous plastic deformation, plastic flow, and accumulation of energy and temperature.
The prevention of adhesive material transfer is accomplished by the following or similar approaches:
* Low-temperature carburizing treatments such as Kolsterising can eliminate galling in austenitic stainless steels by increasing surface hardness up to 1200 HV0.05 (depending on the base material and surface conditions).
* Less cohesive or chemical attraction between surface atoms or molecules.
* Avoid continuous plastic deformation and plastic flow, for example, through a thicker oxide layer on the subject material in sheet-metal forming (SMF).
* Coatings deposited on the SMF work tool, such as chemical vapor deposition (CVD) or physical vapor deposition (PVD) and titanium nitride (TiN) or diamond-like carbon coatings exhibit low chemical reactivity even in high energy frictional contact, where the subject material's protective oxide layer is breached, and the frictional contact is distinguished by continuous plastic deformation and plastic flow.
Lubricated contact places other demands on the surface structure of the materials involved, and the main issue is to retain the protective lubrication thickness and avoid plastic deformation. This is important because plastic deformation raises the temperature of the oil or lubrication fluid and changes the viscosity. Any eventual material transfer or creation of protrusions above the original surface will also reduce the ability to retain a protective lubrication thickness. A proper protective lubrication thickness can be assisted or retained by:
* Surface cavities or small holes can create a favorable geometric situation for the oil to retain a protective lubrication thickness in the contact zone.
* Cohesive forces on the surface can increase the chemical attraction between the surface and lubricants and enhance the lubrication thickness.
* Oil additives may reduce the tendency for galling or adhesive wear. | 0 | Theoretical and Fundamental Chemistry |
The term "swale" or "beach swale" is also used to describe long, narrow, usually shallow troughs between ridges or sandbars on a beach, that run parallel to the shoreline. | 1 | Applied and Interdisciplinary Chemistry |
The detoxification of endogenous reactive metabolites such as peroxides and reactive aldehydes often cannot be achieved by the system described above. This is the result of these species' being derived from normal cellular constituents and usually sharing their polar characteristics. However, since these compounds are few in number, it is possible for enzymatic systems to utilize specific molecular recognition to recognize and remove them. The similarity of these molecules to useful metabolites therefore means that different detoxification enzymes are usually required for the metabolism of each group of endogenous toxins. Examples of these specific detoxification systems are the glyoxalase system, which acts to dispose of the reactive aldehyde methylglyoxal, and the various antioxidant systems that remove reactive oxygen species. | 1 | Applied and Interdisciplinary Chemistry |
* Ganguli, S. (2002). [http://www.ias.ac.in/currsci/jun102002/1303.pdf Neem: A therapeutic for all seasons]. Current Science. 82(11), June. p. 1304
* Siddiqui, S. and Siddiqui, R.H. (1931). Chemical examination of the roots of Rauwolfia serpintina. Journal of the Indian Chemical Society. 8. pp. 667–80.
* Siddiqui, S. and Siddiqui, R.H. (1932). The alkaloids of Rauwolfia serpintina. Part I. Ajmaline series. Journal of the Indian Chemical Society. 9. p. 539.
* Siddiqui, S. and Siddiqui, R.H. (1935). The alkaloids of Rauwolfia serpintina. Part II. Ajmaline series. Journal of the Indian Chemical Society. 12. p. 37.
* Siddiqui, S. (1942). A note on isolation of three new bitter principles from the neem oil. Current Science. 11. pp. 278–79. | 0 | Theoretical and Fundamental Chemistry |
Members of the BMP family were originally found to induce bone formation, as their name suggests. However, BMPs are very multifunctional and can also regulate apoptosis, cell migration, cell division, and differentiation. They also specify the anterior/posterior axis, induce growth, and regulate homeostasis.
The BMPs bind to the bone morphogenetic protein receptor type II (BMPR2). Some of the proteins of the BMP family are BMP4 and BMP7. BMP4 promotes bone formation, causes cell death, or signals the formation of epidermis, depending on the tissue it is acting on. BMP7 is crucial for kidney development, sperm synthesis, and neural tube polarization. Both BMP4 and BMP7 regulate mature ligand stability and processing, including degrading ligands in lysosomes. BMPs act by diffusing from the cells that create them. | 1 | Applied and Interdisciplinary Chemistry |
The society publishes a number of peer-reviewed scientific journals in conjunction with John Wiley & Sons:
* Biofuels, Bioproducts and Biorefining
* Energy Science & Engineering
* Greenhouse Gases: Science and Technology
* Journal of Chemical Technology and Biotechnology
* Journal of the Science of Food and Agriculture
* Polymer International | 1 | Applied and Interdisciplinary Chemistry |
The software is based on the stochastic reactor model (SRM), which is stated in terms of a weighted stochastic particle ensemble. SRM is particular useful in the context of engine modelling
as the dynamics of the particle ensemble includes detailed chemical kinetics whilst accounting for inhomogeneity in composition and temperature space arising from on-going fuel injection, heat transfer and turbulence mixing events. Through this coupling, heat release profiles and in particular the associated exhaust gas emissions (Particulates, NOx, Carbon monoxide, Unburned hydrocarbon etc.) can be predicted more accurately than if using the more conventional approaches of standard homogenous and multi-zone reactor methods. | 1 | Applied and Interdisciplinary Chemistry |
Thioesters are prominent active esters, as illustrated by the esters of coenzyme A.
In synthetic chemistry, active esters include derivatives of nitrophenols and pentafluorophenol. Active esters are often used in peptide synthesis, e.g., N-hydroxysuccinimide, hydroxybenzotriazole. Active esters of acrylic acid are precursors to polymers with reactive side chains.
The concept of active esters extends to esters of phosphoric and sulfuric acids. One such case is dimethylsulfate, a strong methylating agent. | 0 | Theoretical and Fundamental Chemistry |
The original Trail smelter for the nearby Rossland mines, was founded by the American mining engineer F. Augustus Heinze (1869 – 1914) who had already built a smelter in Butte, Montana. In 1896, Heinze initially incorporated his smelting and mining company in the United States and then in Canada. Within a period of 4 years, Heinze owned the "smelter, mining interests, railway lines, railway charters, and associated land grants." Walter Hull Aldridge (b. 1867), an American mining and metallurgical engineer, took a position with the president of the Canadian Pacific Railroad (CPR), Sir William Van Horne, to negotiate a deal with Heinze. Under Aldridges direction, the CPRs mining interests were incorporated under the name of the Consolidated Mining & Smelting Company, then known as the Consolidated or CM&S. At that time, Consolidated "controlled many of British Columbia's largest lead, silver, gold and copper mines, as well as the large reduction works at Trail."
In 1910, CM&S anticipated the decline of its Rossland mines and purchased the lead-zinc ore-rich Sullivan Mine. At that time, it was difficult to smelt ore from the Sullivan mine because of the presence of iron sulphide. A metallurgist from Ontario, Randolphe Ralph William Diamond who was hired by Consolidated, developed the process known as differential flotation that separated minerals by letting them "float" by "sticking to bubbles formed in certain mixtures of chemicals and oils". This ground-breaking technology increased production at the Sullivan Mine making it profitable for decades. It required a "long-term stable workforce" not just itinerant workers; mining towns grew around the mines and smelter. While 1924, was a peak year in terms of production, by 1927, sulphur dioxide (SO2) emissions from the smelter had contaminated the vegetation and the land the Columbia River valley in Washington State. Damages were estimated at $350,000 by the International Joint Commission in 1927.
In 1934, Cominco had initiated heavy water research at the smelter but it did not gain momentum until the outbreak of World War II. During the war, the Allies cooperated in researching nuclear fission with the goal of developing an atomic bomb. New research had revealed that heavy water could slow down the uranium neutron, making a chain reaction possible. Under the tenure of Selwyn G. Blaylock as Comincos president, the smelter was upgraded as part of the Manhattan Projects heavy water production program, under code name the P-9 Project. Princeton University physicist Hugh S. Taylor, who was in charge of United States Office of Scientific Research and Development (OSRD) research on heavy water research, gave Cominco $20,000 towards the upgrade modifications. Cominco produced heavy water for the United States from 1942 until 1956.
In the 1950s, a hydroelectric dam—the Waneta Dam—was built south of Trail on the Pend D’Oreille River, which provided inexpensive electricity to the smelter.
For decades the smelter provided well-paying employment for people who had only a high school education. Intergenerational families worked at the smelter and the company became Trail's "economic and cultural centre."
In the spring of 2017, Teck Resources announced that they were considering a CA$1.2-billion deal to sell its Waneta Dam to BC Hydro. At the time, union members who work at the Teck were concerned about the smelters future. Teck had expanded its operations worldwide and the Trail operations only contributed CA$92 million of Tecks CA$3.3-billion gross profit in 2017. | 1 | Applied and Interdisciplinary Chemistry |
Supercritical fluid chromatography (SFC) can be used on an analytical scale, where it combines many of the advantages of high performance liquid chromatography (HPLC) and gas chromatography (GC). It can be used with non-volatile and thermally labile analytes (unlike GC) and can be used with the universal flame ionization detector (unlike HPLC), as well as producing narrower peaks due to rapid diffusion. In practice, the advantages offered by SFC have not been sufficient to displace the widely used HPLC and GC, except in a few cases such as chiral separations and analysis of high-molecular-weight hydrocarbons. For manufacturing, efficient preparative simulated moving bed units are available. The purity of the final products is very high, but the cost makes it suitable only for very high-value materials such as pharmaceuticals. | 0 | Theoretical and Fundamental Chemistry |
The chemical potential μ of species i (atomic, molecular or nuclear) is defined, as all intensive quantities are, by the phenomenological fundamental equation of thermodynamics. This holds for both reversible and irreversible infinitesimal processes:
where dU is the infinitesimal change of internal energy U, dS the infinitesimal change of entropy S, dV is the infinitesimal change of volume V for a thermodynamic system in thermal equilibrium, and dN is the infinitesimal change of particle number N of species i as particles are added or subtracted. T is absolute temperature, S is entropy, P is pressure, and V is volume. Other work terms, such as those involving electric, magnetic or gravitational fields may be added.
From the above equation, the chemical potential is given by
This is because the internal energy U is a state function, so if its differential exists, then the differential is an exact differential such as
for independent variables x, x, ... , x of U. This expression of the chemical potential as a partial derivative of U with respect to the corresponding species particle number is inconvenient for condensed-matter systems, such as chemical solutions, as it is hard to control the volume and entropy to be constant while particles are added. A more convenient expression may be obtained by making a Legendre transformation to another thermodynamic potential: the Gibbs free energy . From the differential (for and , the product rule is applied to) and using the above expression for , a differential relation for is obtained:
As a consequence, another expression for results:
and the change in Gibbs free energy of a system that is held at constant temperature and pressure is simply
In thermodynamic equilibrium, when the system concerned is at constant temperature and pressure but can exchange particles with its external environment, the Gibbs free energy is at its minimum for the system, that is . It follows that
Use of this equality provides the means to establish the equilibrium constant for a chemical reaction.
By making further Legendre transformations from U to other thermodynamic potentials like the enthalpy and Helmholtz free energy , expressions for the chemical potential may be obtained in terms of these:
These different forms for the chemical potential are all equivalent, meaning that they have the same physical content, and may be useful in different physical situations. | 0 | Theoretical and Fundamental Chemistry |
Thiosemicarbazides are precursors to thiosemicarbazones. They are precursors to heterocycles. Formylation of thiosemicarbazide provides access to triazole. | 0 | Theoretical and Fundamental Chemistry |
The alternative oxidase is an integral monotopic membrane protein that is tightly bound to the inner mitochondrial membrane from matrix side The enzyme has been predicted to contain a coupled diiron center on the basis of a conserved sequence motif consisting of the proposed iron ligands, four glutamate and two histidine amino acid residues. The electron spin resonance study of Arabidopsis thaliana alternative oxidase AOX1a showed that the enzyme contains a hydroxo-bridged mixed-valent Fe(II)/Fe(III) binuclear iron center. A catalytic cycle has been proposed that involves this di-iron center and at least one transient protein-derived free radical, which is probably formed on a tyrosine residue. | 1 | Applied and Interdisciplinary Chemistry |
Since the energy states of valence tautomers affect the IVCT band, the strength of electronic interaction between the sites, known as α (the mixing coefficient), can be determined by analysis of the IVCT band. Depending on the value of α, mixed valence complexes are classified into three groups:
*class I: α ~ 0, the complex has no interaction between redox sites. No IVCT band is observed. The oxidation states of the two metal sites are distinct and do not readily interconvert.
*class II: 0 = 0.707, intermediate interaction between sites. An IVCT band is observed. The oxidation states of the two metal sites are distinct, but they readily interconvert. This is by far the most common class of intervalence complexes.
*class III: α > = 0.707, interaction between redox sites is very strong. It is better to consider these sites as one united site, not as two isolated sites. An IVCT band is observed. The oxidation states of the two metal sites are essentially equivalent. In these situations, the two metals are often best described as having the same half integer oxidation state. | 0 | Theoretical and Fundamental Chemistry |
To conduct the scan, a short-lived radioactive tracer isotope is injected into the living subject (usually into blood circulation). Each tracer atom has been chemically incorporated into a biologically active molecule. There is a waiting period while the active molecule becomes concentrated in tissues of interest. Then the subject is placed in the imaging scanner. The molecule most commonly used for this purpose is FDG, a sugar, for which the waiting period is typically an hour. During the scan, a record of tissue concentration is made as the tracer decays.
As the radioisotope undergoes positron emission decay (also known as positive beta decay), it emits a positron, an antiparticle of the electron with opposite charge. The emitted positron travels in tissue for a short distance (typically less than 1 mm, but dependent on the isotope), during which time it loses kinetic energy, until it decelerates to a point where it can interact with an electron. The encounter annihilates both electron and positron, producing a pair of annihilation (gamma) photons moving in approximately opposite directions. These are detected when they reach a scintillator in the scanning device, creating a burst of light which is detected by photomultiplier tubes or silicon avalanche photodiodes (Si APD). The technique depends on simultaneous or coincident detection of the pair of photons moving in approximately opposite directions (they would be exactly opposite in their center of mass frame, but the scanner has no way to know this, and so has a built-in slight direction-error tolerance). Photons that do not arrive in temporal "pairs" (i.e. within a timing-window of a few nanoseconds) are ignored. | 1 | Applied and Interdisciplinary Chemistry |
The effect of a uniform magnetic field gradient in the z-direction on spin I, is considered to be a rotation around z-axis by an angle = γGz; where Gz is the gradient magnitude (along the z-direction) and γ is the gyromagnetic ratio of spin I. It introduces a phase factor to the magnetizations:
Φ (z,τ) = (γ)(Gz)(τ)
The time duration τ is in the order of milliseconds. | 0 | Theoretical and Fundamental Chemistry |
The analysis of vibronic spectra of diatomic molecules provides information concerning both the ground electronic state and the excited electronic state. Data for the ground state can also be obtained by vibrational or pure rotational spectroscopy, but data for the excited state can only be obtained from the analysis of vibronic spectra. For example, the bond length in the excited state may be derived from the value of the rotational constant B′.
In addition to stable diatomic molecules, vibronic spectroscopy has been used to study unstable species, including CH, NH, hydroxyl radical, OH, and cyano radical, CN. The Swan bands in hydrocarbon flame spectra are a progression in the C-C stretching vibration of the dicarbon radical, C for the electronic transition. Vibronic bands for 9 other electronic transitions of C have been observed in the infrared and ultraviolet regions. | 0 | Theoretical and Fundamental Chemistry |
In crude olive oil production, the traditional system, i.e. pressing, and the three-phase system produce a press cake and a considerable amount of waste water while the two-phase system, which is mainly used in Spain, produces a paste-like waste called "alperujo" or "two-phase pomace" that has a higher water content and is more difficult to treat than traditional solid waste. The water content of the press cake, composed of crude olive cake, pomace and husk, is about 30 percent if it is produced by traditional pressing technology and about 45–50 percent using decanter centrifuges. The press cake still has some oil that is normally recovered in a separate installation. The exhausted olive cake is incinerated or used as a soil conditioner in olive groves. | 0 | Theoretical and Fundamental Chemistry |
For a one-dimensional crystal of size
where the factor in parentheses comes from the fact the sum is over nearest-neighbour pairs (), next nearest-neighbours (), ... and for a crystal of planes, there are pairs of nearest neighbours, pairs of next-nearest neighbours, etc. | 0 | Theoretical and Fundamental Chemistry |
A 4-port valve is a valve whose body has four ports equally spaced round the body and the disc has two passages to connect adjacent ports. It is operated with two positions.
It can be used to isolate and to simultaneously bypass a sampling cylinder installed on a pressurized water line. It is useful to take a fluid sample without affecting the pressure of a hydraulic system and to avoid degassing (no leak, no gas loss or air entry, no external contamination).... | 1 | Applied and Interdisciplinary Chemistry |
Before the advent of technologies that analyze whole molecules for their intramolecular isotopic structure, molecules were sequentially degraded and converted to CO and measured on an Isotope Ratio Mass Spectrometer, revealing position-specific C enrichments. | 0 | Theoretical and Fundamental Chemistry |
Gerardus Johannes Mulder or Gerrit Jan Mulder (27 December 1802 – 18 April 1880) was a Dutch organic and analytical chemist. | 0 | Theoretical and Fundamental Chemistry |
In HR-CS AAS background correction is carried out mathematically in the software using information from detector pixels that are not used for measuring atomic absorption; hence, in contrast to LS AAS, no additional components are required for background correction. | 0 | Theoretical and Fundamental Chemistry |
Environment-sensitive dyes change their properties (intensity, half-life, and excitation and emission spectra) depending on the polarity (hydrophobicity and charge) of their environments. Examples include: Indole, Cascade Yellow, prodan, Dansyl, Dapoxyl, NBD, PyMPO, Pyrene and diethylaminocumarin.<br />
This change is most pronounced when electron-donating and electron-withdrawing groups are placed at opposite ends of an aromatic ring system, as this results in a large change in dipole moment when excited.
When a fluorophore is excited, it generally has a larger dipole moment (μ) than in the ground state (μ). Absorption of a photon by a fluorophore takes a few picoseconds. Before this energy is released (emission: 1–10 ns), the solvent molecules surrounding the fluorophore reorient (10–100 ps) due to the change in polarity in the excited singlet state; this process is called solvent relaxation. As a result of this relaxation, the energy of the excited state of the fluorophore is lowered (longer wavelength), hence fluorophores that have a large change in dipole moment have larger stokes shift changes in different solvents. The difference between the energy levels can be roughly determined with the Lipper-Mataga equation.
A hydrophobic dye is a dye which is insoluble in water, a property independent of solvatochromism. <br>Additionally, The term environment-sensitive in chemistry actually describes changes due to one of a variety of different environmental factors, such as pH or temperature, not just polarity; however, in biochemistry environment-sensitive fluorphore and solvatochromic fluorophore are used interchangeably: this convention is so widespread that suppliers describe them as environment-sensitive over solvatochromic. | 1 | Applied and Interdisciplinary Chemistry |
Vertebrates can also biosynthesize defensive chemicals or sequester them from plants or prey. Sequestered compounds have been observed in frogs, natricine snakes, and two genera of birds, Pitohui and Ifrita. It is suspected that some well-known compounds such as tetrodotoxin produced by newts and pufferfish are derived from invertebrate prey. Bufadienolides, defensive chemicals produced by toads, have been found in glands of natricine snakes used for defense. | 1 | Applied and Interdisciplinary Chemistry |
Cereals & Grains Association publishes Cereal Chemistry, a bimonthly publication in cereal science, including processing, oils, and laboratory tests on these grains (corn, oat, barley, rye, etc.), Cereal Foods World, the bi-monthly magazine of the association that deals with research papers and professional issues related to those who are involved in cereal science, and books on different issues relating to grains and cereals (storage, milling, processing, food quality, food safety, ingredients, dietary fiber, and nutrition). | 1 | Applied and Interdisciplinary Chemistry |
Dianins compound (4-p-hydroxyphenyl-2,2,4-trimethylchroman) was first prepared by Aleksandr Dianin in 1914. This compound is a condensation isomer of bisphenol A and acetone and of special importance in host–guest chemistry because it can form a large variety of clathrates with suitable guest molecules. One example is the clathrate of Dianins compound with morpholine. Slow evaporation of a solution containing both organic compounds yields crystals. Each asymmetric unit cell making up the crystal contains six chroman molecules of which two are deprotonated and two protonated morpholine molecules. The six chroman molecules are racemate pairs. | 0 | Theoretical and Fundamental Chemistry |
*[http://rruff.geo.arizona.edu/AMS/amcsd.php American Mineralogist Crystal Structure Database (AMCSD)] (contents: crystal structures of minerals, access: free, size: large)
*[http://www.ccdc.cam.ac.uk/products/csd/ Cambridge Structural Database (CSD)] (contents: crystal structures of organics and metal-organics, access: restricted, size: very large)
*Crystallography Open Database (COD) (contents: crystal structures of organics, metalorganics, minerals, inorganics, metals, alloys, and intermetallics, access: free, size: very large)
*[http://crystallography.io/ COD+] (Web Interface for COD) (contents: crystal structures of organics, metalorganics, minerals, inorganics, metals, alloys, and intermetallics, access: free, size: very large)
*[http://www.iza-structure.org/databases/ Database of Zeolite Structures] (contents: crystal structures of zeolites, access: free, size: small)
*[http://www.cryst.ehu.es/icsdb/index.html Incommensurate Structures Database] (contents: incommensurate structures, access: free, size: small)
*Inorganic Crystal Structure Database (ICSD) (contents: crystal structures of minerals and inorganics, access: restricted, size: large)
*[http://materialsproject.org MaterialsProject Database] (contents: crystal structures of inorganic compounds, access: free, size: large)
*[https://mpds.io Materials Platform for Data Science (MPDS) or PAULING FILE] (contents: critically evaluated crystal structures, as well as physical properties and phase diagrams, from the world scientific literature, access: partially free, size: very large)
*[http://materialsweb.org MaterialsWeb Database] (contents: crystal structures of inorganic 2D materials and bulk compounds, access: free, size: large)
*[https://web.archive.org/web/20080622165920/http://tothcanada.com/databases.htm Metals Structure Database (CRYSTMET)] (contents: crystal structures of metals, alloys, and intermetallics, access: restricted, size: large)
*[http://webmineral.com/ Mineralogy Database] (contents: crystal structures of minerals, access: free, size: medium)
*[http://database.iem.ac.ru/mincryst/index.php MinCryst] (contents: crystal structures of minerals, access: free, size: medium)
*[https://web.archive.org/web/20080516022153/http://www.nist.gov/srd/nist83.htm NIST Structural Database NIST Structural Database] (contents: crystal structures of metals, alloys, and intermetallics, access: restricted, size: large)
*[https://web.archive.org/web/20080610153131/http://www.nist.gov/srd/nist42.htm NIST Surface Structure Database] (contents: surface and interface structures, access: restricted, size: small-medium)
*[http://ndbserver.rutgers.edu/ Nucleic Acid Database] (contents: crystal and molecular structures of nucleic acids, access: free, size: medium)
*[http://www.crystalimpact.com/pcd/Default.htm Pearson's Crystal Data] (contents: crystal structures of inorganics, minerals, salts, oxides, hydrides, metals, alloys, and intermetallics, access: restricted, size: very large)
*[http://www.wwpdb.org/ Worldwide Protein Data Bank (PDB)] (contents: crystal and molecular structures of biological macromolecules, access: free, size: very large)
*[http://nanocrystallography.research.pdx.edu/search/wcd/ Wiki Crystallography Database (WCD)] (contents: crystal structures of organics, metalorganics, minerals, inorganics, metals, alloys, and intermetallics, access: free, size: medium) | 0 | Theoretical and Fundamental Chemistry |
Complexes of oxophilic metals typically are prone to hydrolysis. For example, the high valent chlorides hydrolyze rapidly to give oxides:
:TiCl + 2 HO → TiO + 4 HCl
These reactions proceed via oxychloride intermediates. For example, WOCl results from the partial hydrolysis of tungsten hexachloride. Hydroxide-containing intermediates are rarely observed for oxophilic metals. In contrast, the anhydrous halides of the later metals tend to hydrate, not hydrolyze, and they often form hydroxides.
Reduced complexes of oxophilic metals tend to generate oxides by reaction with oxygen. Typically the oxide-ligand is bridging, e.g.
:2 (CH)TiCl + 1/2 O → {(CH)TiCl}O
Only in rare cases do the products of oxygenation feature terminal oxo ligands. | 0 | Theoretical and Fundamental Chemistry |
Walden was born in Rozulas in the Russian Empire (now Stalbe parish, Pārgauja municipality, Latvia) in a large Latvian peasant family. At the age of four, he lost his father and later his mother. Thanks to financial support from his two older brothers who lived in Riga (one was a merchant and another served as a lieutenant in the military) Walden managed to complete his education – first graduated with honors from the district school in the town of Cēsis (1876), and then from the Riga Technical High School (1882).
In December 1882, he enrolled into the Riga Technical University and became seriously interested in chemistry. In 1886, he published his first scientific study on the color evaluation of the reactions of nitric and nitrous acid with various reagents and establishing the limits of sensitivity of the color method to detection of nitric acid.
In April 1887, Walden became an active member of the Russian Physico-chemical Society. During this time, Walden started his collaboration with Wilhelm Ostwald (Nobel Prize in Chemistry 1909) which greatly influenced his development as a scientist. Their first work together was published in 1887 and was devoted to the dependence of the electrical conductivity of aqueous solutions of salts on their molecular weight. | 0 | Theoretical and Fundamental Chemistry |
Alacepril (INN) is an ACE inhibitor medication indicated as a treatment for hypertension. The medication metabolizes to captopril and desacetylalacepril. Alacepril is primarily used to treat hypertension, and in some cases, renovascular hypertension. It's often combined with other medications, particularly other blood pressure lowering classes of medications like thiazide diuretics to maximize its effectiveness. | 0 | Theoretical and Fundamental Chemistry |
An initial assumption is that the number of molecular orbitals is equal to the number of atomic orbitals included in the linear expansion. In a sense, n atomic orbitals combine to form n molecular orbitals, which can be numbered i = 1 to n and which may not all be the same. The expression (linear expansion) for the i th molecular orbital would be:
or
where is a molecular orbital represented as the sum of n atomic orbitals , each multiplied by a corresponding coefficient , and r (numbered 1 to n) represents which atomic orbital is combined in the term. The coefficients are the weights of the contributions of the n atomic orbitals to the molecular orbital. The Hartree–Fock method is used to obtain the coefficients of the expansion.
The orbitals are thus expressed as linear combinations of basis functions, and the basis functions are single-electron functions which may or may not be centered on the nuclei of the component atoms of the molecule. In either case the basis functions are usually also referred to as atomic orbitals (even though only in the former case this name seems to be adequate). The atomic orbitals used are typically those of hydrogen-like atoms since these are known analytically i.e. Slater-type orbitals but other choices are possible such as the Gaussian functions from standard basis sets or the pseudo-atomic orbitals from plane-wave pseudopotentials.
By minimizing the total energy of the system, an appropriate set of coefficients of the linear combinations is determined. This quantitative approach is now known as the Hartree–Fock method. However, since the development of computational chemistry, the LCAO method often refers not to an actual optimization of the wave function but to a qualitative discussion which is very useful for predicting and rationalizing results obtained via more modern methods. In this case, the shape of the molecular orbitals and their respective energies are deduced approximately from comparing the energies of the atomic orbitals of the individual atoms (or molecular fragments) and applying some recipes known as level repulsion and the like. The graphs that are plotted to make this discussion clearer are called correlation diagrams. The required atomic orbital energies can come from calculations or directly from experiment via Koopmans' theorem.
This is done by using the symmetry of the molecules and orbitals involved in bonding, and thus is sometimes called symmetry adapted linear combination (SALC). The first step in this process is assigning a point group to the molecule. Each operation in the point group is performed upon the molecule. The number of bonds that are unmoved is the character of that operation. This reducible representation is decomposed into the sum of irreducible representations. These irreducible representations correspond to the symmetry of the orbitals involved.
Molecular orbital diagrams provide simple qualitative LCAO treatment. The Hückel method, the extended Hückel method and the Pariser–Parr–Pople method, provide some quantitative theories. | 0 | Theoretical and Fundamental Chemistry |
Bland and Altman drive the point that any two methods that are designed to measure the same parameter (or property) should have good correlation when a set of samples are chosen such that the property to be determined varies considerably. A high correlation for any two methods designed to measure the same property could thus in itself just be a sign that one has chosen a widespread sample. A high correlation does not necessarily imply that there is good agreement between the two methods. | 0 | Theoretical and Fundamental Chemistry |
Phosphorylation involves the transfer of phosphate groups from ATP to the enzyme, the energy for which comes from hydrolysing ATP into ADP or AMP. However, dephosphorylation releases phosphates into solution as free ions, because attaching them back to ATP would require energy input.
Cysteine-dependent phosphatases (CDPs) catalyse the hydrolysis of a phosphoester bond via a phospho-cysteine intermediate.
The free cysteine nucleophile forms a bond with the phosphorus atom of the phosphate moiety, and the P-O bond linking the phosphate group to the tyrosine is protonated, either by a suitably positioned acidic amino acid residue (Asp in the diagram below) or a water molecule. The phospho-cysteine intermediate is then hydrolysed by another water molecule, thus regenerating the active site for another dephosphorylation reaction.
Metallo-phosphatases (e.g. PP2C) co-ordinate 2 catalytically essential metal ions within their active site. There is currently some confusion of the identity of these metal ions, as successive attempts to identify them yield different answers. There is currently evidence that these metals could be Magnesium, Manganese, Iron, Zinc, or any combination thereof. It is thought that a hydroxyl ion bridging the two metal ions takes part in nucleophilic attack on the phosphorus ion. | 1 | Applied and Interdisciplinary Chemistry |
The Nusselt number is the ratio of total heat transfer (convection + conduction) to conductive heat transfer across a boundary. The convection and conduction heat flows are parallel to each other and to the surface normal of the boundary surface, and are all perpendicular to the mean fluid flow in the simple case.
where h is the convective heat transfer coefficient of the flow, L is the characteristic length, and k is the thermal conductivity of the fluid.
* Selection of the characteristic length should be in the direction of growth (or thickness) of the boundary layer; some examples of characteristic length are: the outer diameter of a cylinder in (external) cross flow (perpendicular to the cylinder axis), the length of a vertical plate undergoing natural convection, or the diameter of a sphere. For complex shapes, the length may be defined as the volume of the fluid body divided by the surface area.
* The thermal conductivity of the fluid is typically (but not always) evaluated at the film temperature, which for engineering purposes may be calculated as the mean-average of the bulk fluid temperature and wall surface temperature.
In contrast to the definition given above, known as average Nusselt number, the local Nusselt number is defined by taking the length to be the distance from the surface boundary to the local point of interest.
The mean, or average, number is obtained by integrating the expression over the range of interest, such as: | 1 | Applied and Interdisciplinary Chemistry |
Delbrück scattering, the deflection of high-energy photons in the Coulomb field of nuclei as a consequence of vacuum polarization, was observed in 1975. The related process of the scattering of light by light, also a consequence of vacuum polarization, was not observed until 1998. In both cases, it is a process described by quantum electrodynamics. | 0 | Theoretical and Fundamental Chemistry |
In the wave theory of physics and engineering, a mode in a dynamical system is a standing wave state of excitation, in which all the components of the system will be affected sinusoidally at a fixed frequency associated with that mode.
Because no real system can perfectly fit under the standing wave framework, the mode concept is taken as a general characterization of specific states of oscillation, thus treating the dynamic system in a linear fashion, in which linear superposition of states can be performed.
Classical examples include
* In a mechanical dynamical system, a vibrating rope is the most clear example of a mode, in which the rope is the medium, the stress on the rope is the excitation, and the displacement of the rope with respect to its static state is the modal variable.
* In an acoustic dynamical system, a single sound pitch is a mode, in which the air is the medium, the sound pressure in the air is the excitation, and the displacement of the air molecules is the modal variable.
* In a structural dynamical system, a high tall building oscillating under its most flexural axis is a mode, in which all the material of the building -under the proper numerical simplifications- is the medium, the seismic/wind/environmental solicitations are the excitations and the displacements are the modal variable.
* In an electrical dynamical system, a resonant cavity made of thin metal walls, enclosing a hollow space, for a particle accelerator is a pure standing wave system, and thus an example of a mode, in which the hollow space of the cavity is the medium, the RF source (a Klystron or another RF source) is the excitation and the electromagnetic field is the modal variable.
* When relating to music, normal modes of vibrating instruments (strings, air pipes, drums, etc.) are called "overtones".
The concept of normal modes also finds application in other dynamical systems, such as optics, quantum mechanics, atmospheric dynamics and molecular dynamics.
Most dynamical systems can be excited in several modes, possibly simultaneously. Each mode is characterized by one or several frequencies, according to the modal variable field. For example, a vibrating rope in 2D space is defined by a single-frequency (1D axial displacement), but a vibrating rope in 3D space is defined by two frequencies (2D axial displacement).
For a given amplitude on the modal variable, each mode will store a specific amount of energy because of the sinusoidal excitation.
The normal or dominant mode of a system with multiple modes will be the mode storing the minimum amount of energy for a given amplitude of the modal variable, or, equivalently, for a given stored amount of energy, the dominant mode will be the mode imposing the maximum amplitude of the modal variable. | 0 | Theoretical and Fundamental Chemistry |
In molecular biology, housekeeping genes are typically constitutive genes that are required for the maintenance of basic cellular function, and are expressed in all cells of an organism under normal and patho-physiological conditions. Although some housekeeping genes are expressed at relatively constant rates in most non-pathological situations, the expression of other housekeeping genes may vary depending on experimental conditions.
The origin of the term "housekeeping gene" remains obscure. Literature from 1976 used the term to describe specifically tRNA and rRNA. For experimental purposes, the expression of one or multiple housekeeping genes is used as a reference point for the analysis of expression levels of other genes. The key criterion for the use of a housekeeping gene in this manner is that the chosen housekeeping gene is uniformly expressed with low variance under both control and experimental conditions. Validation of housekeeping genes should be performed before their use in gene expression experiments such as RT-PCR. Recently a web-based database of [http://www.housekeeping.unicamp.br/?homePageHuman human] and [http://www.housekeeping.unicamp.br/?homePageMouse mouse] housekeeping genes and reference genes/transcripts, named [http://www.housekeeping.unicamp.br/ Housekeeping and Reference Transcript Atlas] (HRT Atlas), was developed to offer updated list of housekeeping genes and reliable candidate reference genes/transcripts for RT-qPCR data normalization. This database can be accessed at http://www.housekeeping.unicamp.br. | 1 | Applied and Interdisciplinary Chemistry |
Perera is the pioneer campaigner in Sri Lanka for Social Inclusion focusing equal opportunity, justice and dignity for People of ALL Abilities in day-to-day life – the key concept in this context being universal design for inclusion of people.- (meaning construction of environments that enable by design so as to include all and exclude none.) | 0 | Theoretical and Fundamental Chemistry |
The society acknowledges individual achievement with prizes and awards, including:
* Raymond Berr Prize
:* 1954: Charles Glacet
:* 1955: Raymond Jean Calas
:* 1958: Guy Ourisson
:* 1961: Marc Julia
:* 1965: Robert Collongues
:* 1967: Jean-Pierre Ebel
:* 1970: Pierre Potier
:* 1972: Jean Flahaut
:* 1976: Henri B. Kagan
:* 1978: Jean-Marie Lehn
:* 1979: J. P. Kovalevsky
:* 1981: Bernard Trémillon
:* 1985: Philippe Sautet
:* 1988: François Mathey
:* 1993: Pierre Sigwalt
* Lavoisier Medal of the Société Chimique de France is awarded to a person or institution in order to distinguish the work or actions which have enhanced the perceived value of chemistry in society.
:* 1904: James Dewar
:* 1906: William Perkin
:* 1912: Victor Grignard
:* 1922: Theodore William Richards
:* 1935: Cyril Norman Hinshelwood
:* 1948: Alexander R. Todd, Baron Todd
:* 1949: Rudolf Signer
:* 1954: Iraj Lalezari
:* 1955: Karl Ziegler
:* 1968: Robert Burns Woodward
:* 1983: Paul B. Weisz
:* 1992: Marc Julia and Raymond Wey
:* 1993: William M. Hess, Armand Lattes, Ernest Maréchal, Eugène Papirer and L.-A. Plaquette
:* 1994: David A. Evans; Marco Aurelio de Paoli; Rudolph Marcus; Steven Wolff
:* 1995: Derek Barton; Rudolf Hoppe
:* 1997: Jean-Marie Lehn
:* 1998: Jean-Baptiste Donnet
:* 1999: Gesellschaft Deutscher Chemiker (GDCh)
:* 2000: F. Albert Cotton
:* 2004: Fred McLafferty
:* 2013: Gérard Férey
:* 2015: Jacques Livage, Henri B. Kagan
:* 2018: Christian Amatore
:* 2023: Jean-Marie Tarascon | 1 | Applied and Interdisciplinary Chemistry |
Fission cross sections are a measurable property related to the probability that fission will occur in a nuclear reaction. Cross sections are a function of incident neutron energy, and those for and are a million times higher than at lower neutron energy levels. Absorption of any neutron makes available to the nucleus binding energy of about 5.3 MeV. needs a fast neutron to supply the additional 1 MeV needed to cross the critical energy barrier for fission. In the case of however, that extra energy is provided when adjusts from an odd to an even mass. In the words of Younes and Lovelace, "...the neutron absorption on a target forms a nucleus with excitation energy greater than the critical fission energy, whereas in the case of n + , the resulting nucleus has an excitation energy below the critical fission energy."
About 6 MeV of the fission-input energy is supplied by the simple binding of an extra neutron to the heavy nucleus via the strong force; however, in many fissionable isotopes, this amount of energy is not enough for fission. Uranium-238, for example, has a near-zero fission cross section for neutrons of less than 1 MeV energy. If no additional energy is supplied by any other mechanism, the nucleus will not fission, but will merely absorb the neutron, as happens when absorbs slow and even some fraction of fast neutrons, to become . The remaining energy to initiate fission can be supplied by two other mechanisms: one of these is more kinetic energy of the incoming neutron, which is increasingly able to fission a fissionable heavy nucleus as it exceeds a kinetic energy of 1 MeV or more (so-called fast neutrons). Such high energy neutrons are able to fission directly (see thermonuclear weapon for application, where the fast neutrons are supplied by nuclear fusion). However, this process cannot happen to a great extent in a nuclear reactor, as too small a fraction of the fission neutrons produced by any type of fission have enough energy to efficiently fission (fission neutrons have a mode energy of 2 MeV, but a median of only 0.75 MeV, meaning half of them have less than this insufficient energy).
Among the heavy actinide elements, however, those isotopes that have an odd number of neutrons (such as U with 143 neutrons) bind an extra neutron with an additional 1 to 2 MeV of energy over an isotope of the same element with an even number of neutrons (such as U with 146 neutrons). This extra binding energy is made available as a result of the mechanism of neutron pairing effects, which itself is caused by the Pauli exclusion principle, allowing an extra neutron to occupy the same nuclear orbital as the last neutron in the nucleus. In such isotopes, therefore, no neutron kinetic energy is needed, for all the necessary energy is supplied by absorption of any neutron, either of the slow or fast variety (the former are used in moderated nuclear reactors, and the latter are used in fast-neutron reactors, and in weapons).
According to Younes and Loveland, "Actinides like that fission easily following the absorption of a thermal (0.25 meV) neutron are called fissile, whereas those like that do not easily fission when they absorb a thermal neutron are called fissionable." | 0 | Theoretical and Fundamental Chemistry |
Wood-tar creosote is a colourless to yellowish greasy liquid with a smoky odor, produces a sooty flame when burned, and has a burned taste. It is non-buoyant in water, with a specific gravity of 1.037 to 1.087, retains fluidity at a very low temperature, and boils at 205-225 °C. In its purest form, it is transparent. Dissolution in water requires up to 200 times the amount of water as the base creosote. This creosote is a combination of natural phenols: primarily guaiacol and creosol (4-methylguaiacol), which typically constitutes 50% of the oil; second in prevalence are cresol and xylenol; the rest being a combination of monophenols and polyphenols.
The simple phenols are not the only active element in wood-tar creosote. In solution, they coagulate albumin, which is a water-soluble protein found in meat, so they serve as a preserving agent, but also cause denaturation. Most of the phenols in the creosote are methoxy derivatives: they contain the methoxy group linked to the benzene nucleus. The high level of methyl derivates created from the action of heat on wood (also apparent in the methyl alcohol produced through distillation) make wood-tar creosote substantially different from coal-tar creosote. Guaiacol is a methyl ether of pyrocatechin, while creosol is a methyl ether of methyl-pyrocatechin, the next homolog of pyrocatechin. Methyl ethers differ from simple phenols in being less hydrophilic, caustic, and poisonous. This allows meat to be successfully preserved without tissue denaturation, and allows creosote to be used as a medical ointment.
Because wood-tar creosote is used for its guaiacol and creosol content, it is generally derived from beechwood rather than other woods, since it distills with a higher proportion of those chemicals to other phenolics. The creosote can be obtained by distilling the wood tar and treating the fraction heavier than water with a sodium hydroxide solution. The alkaline solution is then separated from the insoluble oily layer, boiled in contact with air to reduce impurities, and decomposed by diluted sulfuric acid. This produces a crude creosote, which is purified by re-solution in alkali, re-precipitation with acid, then redistilled with the fraction passing over between 200° and 225° constituting the purified creosote.
When ferric chloride is added to a dilute solution, it will turn green: a characteristic of ortho-oxy derivatives of benzene. It dissolves in sulfuric acid to a red liquid, which slowly changes to purple-violet. Shaken with hydrochloric acid in the absence of air, it becomes red, the color changing in the presence of air to dark brown or black.
In preparation of food by smoking, guaiacol contributes mainly to the smoky taste, while the dimethyl ether of pyrogallol, syringol, is the main chemical responsible for the smoky aroma. | 0 | Theoretical and Fundamental Chemistry |
We may make a more elaborate calculation by treating the atmosphere as compounded of many thin layers. For each such layer, at height y and thickness dy, the weight of this layer in determining the radiation temperaure seen from outer space is a generalization of the expression arrived at earlier for the troposphere. It is:
where OD(y) is the optical depth of the part of the atmosphere from y upwards.
The total effect of CO on the radiation at wavelengths λ to λ+dλ is therefore:
where B is the expression for radiation according to Planck's law presented above:
and the infinity here can be taken actually as the top of the tropopause.
Thus the effect of a relative change in CO concentration, dN/N = dn/n (where n is the density number near ground), would be (noting that dN/N = d(ln N) = d(ln n):
where we have used integration by part.
Because B does not depend on N, and because , we have:
Now, is constant in the troposphere and zero in the tropopause. We denote the height of the border between them as U. So:
The optical depth is proportional to the integral of the number density over y, as does the pressure. Therefore, OD(y) is proportional to the pressure p(y), which within the troposphere (height 0 to U) falls exponentially with decay constant 1/H (H~5.6 km for CO), thus:
Since + constant, viewed as a function of both y and N, we have:
And therefore differentiating with respect to ln N is the same as differentiating with respect to y, times a factor of .
We arrive at:
Since the temperature only changes by ~25% within the troposphere, one may take a (rough) linear approximation of B with T at the relevant wavelengths, and get:
Due to the linear approximation of B we have:
with T taken at H, so that totally:
giving the same result as in the one-layer model presented above, as well as the logarithmic dependence on N, except that now we see T is taken at 5.6 km (the pressure drop height scale), rather than 6.3 km (the density drop height scale). | 1 | Applied and Interdisciplinary Chemistry |
Technetium-99m is a gamma emitter. It is obtained on-site at the imaging center as the soluble pertechnetate which is eluted from a technetium-99m generator, and then either used directly as this soluble salt, or else used to synthesize a number of technetium-99m-based radiopharmaceuticals. | 0 | Theoretical and Fundamental Chemistry |
Because steric effects have profound impact on properties, the steric properties of substituents have been assessed by numerous methods. | 0 | Theoretical and Fundamental Chemistry |
In plants, the first step in the light-independent reactions of photosynthesis is the fixation of by the enzyme RuBisCO to form 3-phosphoglycerate. However, RuBisCo has a dual carboxylase and oxygenase activity. Oxygenation results in part of the substrate being oxidized rather than carboxylated, resulting in loss of substrate and consumption of energy, in what is known as photorespiration. Oxygenation and carboxylation are competitive, meaning that the rate of the reactions depends on the relative concentration of oxygen and .
In order to reduce the rate of photorespiration, plants increase the concentration of around RuBisCO. To do so two partially isolated compartments differentiate within leaves, the mesophyll and the bundle sheath. Instead of direct fixation by RuBisCO, is initially incorporated into a four-carbon organic acid (either malate or aspartate) in the mesophyll. The organic acids then diffuse through plasmodesmata into the bundle sheath cells. There, they are decarboxylated creating a -rich environment. The chloroplasts of the bundle sheath cells convert this into carbohydrates by the conventional pathway.
There is large variability in the biochemical features of C4 assimilation, and it is generally grouped in three subtypes, differentiated by the main enzyme used for decarboxylation ( NADP-malic enzyme, NADP-ME; NAD-malic enzyme, NAD-ME; and PEP carboxykinase, PEPCK). Since PEPCK is often recruited atop NADP-ME or NAD-ME it was proposed to classify the biochemical variability in two subtypes. For instance, maize and sugarcane use a combination of NADP-ME and PEPCK, millet uses preferentially NAD-ME and Megathyrsus maximus, uses preferentially PEPCK. | 0 | Theoretical and Fundamental Chemistry |
: Genomic selection is a novel approach to traditional marker-assisted selection where selection is made based on only a few markers. Rather than seeking to identify individual loci significantly associated with a trait, genomics uses all marker data as predictors of performance and consequently delivers more accurate predictions. Selection can be based on genomic selection predictions, potentially leading to more rapid and lower cost gains from breeding. Genomic prediction combines marker data with phenotypic and pedigree data (when available) in an attempt to increase the accuracy of the prediction of breeding and genotypic values. | 1 | Applied and Interdisciplinary Chemistry |
:V09GX01 Thallium (Tl) chloride
:V09GX02 Indium (In) imciromab
:V09GX03 Chromium (Cr) chromate labelled cells
:V09GX04 Rubidium (Rb) chloride
:V09GX05 Ammonia (N) | 1 | Applied and Interdisciplinary Chemistry |
Persistent organic pollutants such as dichlorodiphenyltrichloroethane (DDT), polychlorinated biphenols, dioxins, are all assessed in AOX analysis. Generally, the higher the amount of chlorine in an organic compound, the more toxic it is considered. While there are several biochemical or electrochemical methods to remove organic halides, AOX has been preferred due to its low cost of operation and simplicity of design.
In a lab, the determination of AOX parameter consists of adsorption of organic halides from the sample on to an activated carbon. The activated carbon can be powdered or granular and adsorbed using microcolumns or a batch process, if the samples are rich in humic acids. Vigorous shaking is often employed in the event of a batch process to favor the adsorption of organic halide on to the activated carbon due to its electronegativity and presence of lone pairs. The inorganic halides that are also adsorbed are washed away using a strong acid such as nitric acid. The carbon with adsorbed organic halide is obtained by filtration, after which the filter containing the carbon is burnt in the presence of oxygen. While combustion of hydrocarbon part of the compounds form CO and HO, halo acids are formed from the halogens. These haloacids are absorbed into acetic acid. Subsequent use of microcolumetric titration, an electrochemical quantification method, provides the AOX content in the sample. Using the dilution ratio, the total AOX content at the location can be estimated. Alternatively, the chlorinated compounds in the sample can be determined by using pentane extraction followed by capillary gas chromatography and electron capture (GC-ECD). The organic carbon that was remaining after the nitric acid purge can be analyzed using UV-persulfate wet oxidation followed by Infrared-detection (IR). Several other analytical techniques such as high performance liquid chromatography (HPLC) could also be implemented to quantify AOX levels. The general adsorption procedure is given below:
Where is the activated carbon and is any organic halide.
is the organic halide - activated carbon complex that can be filtered out. | 1 | Applied and Interdisciplinary Chemistry |
In eukaryotic organisms, pre-mRNA is transcribed in the nucleus, introns are spliced out, then the mature mRNA is exported from the nucleus to the cytoplasm. The small subunit of the ribosome usually starts by binding at the 5 end of the mRNA and is joined there by various other eukaryotic initiation factors, forming the initiation complex. The initiation complex scans along the mRNA strand until it reaches a start codon, and then the large subunit of the ribosome attaches to the small subunit and translation of a protein begins. This entire process is referred to as gene expression; it is the process by which the information in a gene, encoded as a sequence of bases in DNA, is converted into the structure of a protein. A Morpholino can modify splicing, block translation, or block other functional sites on RNA depending on the Morpholinos base sequence. | 1 | Applied and Interdisciplinary Chemistry |
In August 1997, the plant was included in the list of enterprises of strategic importance for the economy and security of Ukraine.
In 1998, for the first time, the plant was certified as a manufacturer of steel and semi-finished products from it (slabs and open-hearth ingots from carbon and carbon-manganese steel grades of normal and increased strength) according to the rules of the English Lloyd's Register.
In August 2002, on the basis of the blast-furnace and open-hearth shops of the Donetsk Metallurgical Plant, the Donetskstal Metallurgical Plant PJSC was established. The company specializes in the production of:
* foundry and pig iron
* more than 100 varieties of carbon, structural, low-alloyed, alloyed ordinary quality, high-quality and high-quality steel grades
* church bells made of non-ferrous high-quality alloy
* steel electric-welded longitudinal pipes and metal furniture frames
* slag-forming mixtures, granulated slag and building materials
Slabs made of normal strength marine structural steel grades GL-A and GL-B are certified according to the rules of Deutsche Lloyd.
In 2003, the church of St. Ignatius of Mariupol was built on the territory of the plant.
The plant completed 2013 with a net profit of UAH 83.322 million. | 1 | Applied and Interdisciplinary Chemistry |
For concentrated ionic solutions the hydration of ions must be taken into consideration, as done by Stokes and Robinson in their hydration model from 1948. The activity coefficient of the electrolyte is split into electric and statistical components by E. Glueckauf who modifies the Robinson–Stokes model.
The statistical part includes hydration index number , the number of ions from the dissociation and the ratio between the apparent molar volume of the electrolyte and the molar volume of water and molality .
Concentrated solution statistical part of the activity coefficient is:
The Stokes–Robinson model has been analyzed and improved by other investigators as well. | 0 | Theoretical and Fundamental Chemistry |
In thermodynamics, a critical line is the higher-dimensional equivalent of a critical point. It is the
locus of contiguous critical points in a phase diagram. These lines cannot occur for
a single substance due to the phase rule, but they can be observed in systems with more variables, such as mixtures. Two critical lines may meet and terminate in a tricritical point. | 0 | Theoretical and Fundamental Chemistry |
Bose first sent a paper to Einstein on the quantum statistics of light quanta (now called photons), in which he derived Plancks quantum radiation law without any reference to classical physics. Einstein was impressed, translated the paper himself from English to German and submitted it for Bose to the Zeitschrift für Physik, which published it in 1924. (The Einstein manuscript, once believed to be lost, was found in a library at Leiden University in 2005.) Einstein then extended Boses ideas to matter in two other papers. The result of their efforts is the concept of a Bose gas, governed by Bose–Einstein statistics, which describes the statistical distribution of identical particles with integer spin, now called bosons. Bosons, particles that include the photon and atoms such as helium-4 (), are allowed to share a quantum state. Einstein proposed that cooling bosonic atoms to a very low temperature would cause them to fall (or "condense") into the lowest accessible quantum state, resulting in a new form of matter.
In 1938, Fritz London proposed the BEC as a mechanism for superfluidity in and superconductivity.
The quest to produce a Bose–Einstein condensate in the laboratory was stimulated by a paper published in 1976 by two program directors at the National Science Foundation (William Stwalley and Lewis Nosanow). This led to the immediate pursuit of the idea by four independent research groups; these were led by Isaac Silvera (University of Amsterdam), Walter Hardy (University of British Columbia), Thomas Greytak (Massachusetts Institute of Technology) and David Lee (Cornell University).
On 5 June 1995, the first gaseous condensate was produced by Eric Cornell and Carl Wieman at the University of Colorado at Boulder NIST–JILA lab, in a gas of rubidium atoms cooled to 170 nanokelvins (nK). Shortly thereafter, Wolfgang Ketterle at MIT produced a Bose–Einstein Condensate in a gas of sodium atoms. For their achievements Cornell, Wieman, and Ketterle received the 2001 Nobel Prize in Physics. These early studies founded the field of ultracold atoms, and hundreds of research groups around the world now routinely produce BECs of dilute atomic vapors in their labs.
Since 1995, many other atomic species have been condensed, and BECs have also been realized using molecules, quasi-particles, and photons. | 0 | Theoretical and Fundamental Chemistry |
The term methyl violet encompasses three compounds that differ in the number of methyl groups attached to the amine functional group. They are all soluble in water, ethanol, diethylene glycol and dipropylene glycol. | 0 | Theoretical and Fundamental Chemistry |
Battery leakage is the escape of chemicals, such as electrolytes, within an electric battery due to generation of pathways to the outside environment caused by factory or design defects, excessive gas generation, or physical damage to the battery. The leakage of battery chemical often causes destructive corrosion to the associated equipment and may pose a health hazard. | 1 | Applied and Interdisciplinary Chemistry |
Atransferrinemia is associated with a deficiency in transferrin.
In nephrotic syndrome, urinary loss of transferrin, along with other serum proteins such as thyroxine-binding globulin, gammaglobulin, and anti-thrombin III, can manifest as iron-resistant microcytic anemia. | 1 | Applied and Interdisciplinary Chemistry |
In mineralogy, crystal habit is the characteristic external shape of an individual crystal or aggregate of crystals. The habit of a crystal is dependent on its crystallographic form and growth conditions, which generally creates irregularities due to limited space in the crystallizing medium (commonly in rocks). | 0 | Theoretical and Fundamental Chemistry |
Hydrology () is the scientific study of the movement, distribution, and management of water on Earth and other planets, including the water cycle, water resources, and drainage basin sustainability. A practitioner of hydrology is called a hydrologist. Hydrologists are scientists studying earth or environmental science, civil or environmental engineering, and physical geography. Using various analytical methods and scientific techniques, they collect and analyze data to help solve water related problems such as environmental preservation, natural disasters, and water management.
Hydrology subdivides into surface water hydrology, groundwater hydrology (hydrogeology), and marine hydrology. Domains of hydrology include hydrometeorology, surface hydrology, hydrogeology, drainage-basin management, and water quality.
Oceanography and meteorology are not included because water is only one of many important aspects within those fields.
Hydrological research can inform environmental engineering, policy, and planning. | 1 | Applied and Interdisciplinary Chemistry |
Interpolymer complexes can be prepared either by mixing complementary polymers in solutions or by matrix (template) polymerisation. It is also possible to prepare IPCs at liquid-liquid interfaces or at solid or soft surfaces. Usually the structure of IPCs formed will depend on many factors, including the nature of interacting polymers, concentrations of their solutions, nature of solvent and presence of inorganic ions or organic molecules in solutions. Mixing of dilute polymer solutions usually leads to formation of IPCs as a colloidal dispersion, whereas more concentrated polymer solutions form IPCs in the form of a gel. | 0 | Theoretical and Fundamental Chemistry |
Diatomic elements played an important role in the elucidation of the concepts of element, atom, and molecule in the 19th century, because some of the most common elements, such as hydrogen, oxygen, and nitrogen, occur as diatomic molecules. John Daltons original atomic hypothesis assumed that all elements were monatomic and that the atoms in compounds would normally have the simplest atomic ratios with respect to one another. For example, Dalton assumed waters formula to be HO, giving the atomic weight of oxygen as eight times that of hydrogen, instead of the modern value of about 16. As a consequence, confusion existed regarding atomic weights and molecular formulas for about half a century.
As early as 1805, Gay-Lussac and von Humboldt showed that water is formed of two volumes of hydrogen and one volume of oxygen, and by 1811 Amedeo Avogadro had arrived at the correct interpretation of waters composition, based on what is now called Avogadros law and the assumption of diatomic elemental molecules. However, these results were mostly ignored until 1860, partly due to the belief that atoms of one element would have no chemical affinity toward atoms of the same element, and also partly due to apparent exceptions to Avogadro's law that were not explained until later in terms of dissociating molecules.
At the 1860 Karlsruhe Congress on atomic weights, Cannizzaro resurrected Avogadro's ideas and used them to produce a consistent table of atomic weights, which mostly agree with modern values. These weights were an important prerequisite for the discovery of the periodic law by Dmitri Mendeleev and Lothar Meyer. | 0 | Theoretical and Fundamental Chemistry |
Ligands may bridge two or more centres. The prefix μ is used to specify a bridging ligand in both the formula and the name. For example the dimeric form of aluminium trichloride:
: AlCl(μ-Cl)
: di-μ-chlorido-tetrachlorido-1κCl,2κCl-dialuminium
This example illustrates the ordering of bridging and non bridging ligands of the same type. In the formula the bridging ligands follow the non bridging whereas in the name the bridging ligands precede the non bridging. Note the use of the kappa convention to specify that there are two terminal chlorides on each aluminium. | 0 | Theoretical and Fundamental Chemistry |
pRb restricts the cells ability to replicate DNA by preventing its progression from the G1 (first gap phase) to S (synthesis phase) phase of the cell division cycle. pRb binds and inhibits E2 promoter-binding–protein-dimerization partner (E2F-DP) dimers, which are transcription factors of the E2F family that push the cell into S phase. By keeping E2F-DP inactivated, RB1' maintains the cell in the G1 phase, preventing progression through the cell cycle and acting as a growth suppressor. The pRb-E2F/DP complex also attracts a histone deacetylase (HDAC) protein to the chromatin, reducing transcription of S phase promoting factors, further suppressing DNA synthesis. | 1 | Applied and Interdisciplinary Chemistry |
When measuring the concentration of a solute in a supersaturated gaseous or liquid mixture it is obvious that the pressure inside the cuvette may be greater than the ambient pressure. When this is so a specialized cuvette must be used. The choice of analytical technique to use will depend on the characteristics of the analyte. | 0 | Theoretical and Fundamental Chemistry |
As of 2012, Johnson and Johnson was facing around 3400 state and federal lawsuits filed by people who claimed tendon damage from levofloxacin; about 1900 pending in a class action at the United States District Court in Minnesota and about 1500 pending at a district court in New Jersey.
In October 2012, J&J settled 845 cases in the Minnesota action, after Johnson and Johnson prevailed in three of the first four cases to go to trial. By May 2014, all but 363 cases had been settled or adjudicated. | 0 | Theoretical and Fundamental Chemistry |
Simon's reagent is used as a simple spot-test to presumptively identify alkaloids as well as other compounds. It reacts with secondary amines like MDMA and methamphetamine to give a blue solution. | 0 | Theoretical and Fundamental Chemistry |
Aliphatic azo compounds (R and/or R′ = aliphatic) are less commonly encountered than the aryl azo compounds. A commercially important alkyl azo compound is azobisisobutyronitrile (AIBN), which is widely used as an initiator in free-radical polymerizations and other radical-induced reactions. It achieves this initiation by decomposition, eliminating a molecule of nitrogen gas to form two 2-cyanoprop-2-yl radicals:
For instance a mixture of styrene and maleic anhydride in toluene will react if heated, forming the copolymer upon addition of AIBN.
A simple dialkyl diazo compound is diethyldiazene, , which can be synthesized through a variant of the Ramberg–Bäcklund reaction. Because of their instability, aliphatic azo compounds pose the risk of explosion.
AIBN is produced by converting acetone cyanohydrin to the hydrazine derivative followed by oxidation: | 0 | Theoretical and Fundamental Chemistry |
PCBs have low water solubility, so they adhere tightly to soil and cannot be easily accessed by bacteria. Especially, if the contaminations site has been exposed to PCBs for long period, PCBs can be integrated into soil or sediment matrices, then further decrease their bioavailability. Some surfactants can help solubilize but cannot increase the rate of PCBs degrading. However, if PCBs are linked to surfactants tightly too, then this process cannot promote the absorption of PCBs and even lower it. Also, many surfactants have been proven to be toxic to cells and the high cost of surfactants is another issues. | 1 | Applied and Interdisciplinary Chemistry |
Karl Schwarzschild in 1906 considered a system in which convection and radiation both operated but radiation was so much more efficient than convection that convection could be, as an approximation, neglected, and radiation could be considered predominant. This applies when the temperature is very high, as for example in a star, but not in a planet's atmosphere.
Subrahmanyan Chandrasekhar (1950, page 290) writes of a model of a stellar atmosphere in which "there are no mechanisms, other than radiation, for transporting heat within the atmosphere ... [and] there are no sources of heat in the surrounding" This is hardly different from Schwarzschild's 1906 approximate concept, but is more precisely stated. | 0 | Theoretical and Fundamental Chemistry |
If MRL of some medicinal plant is not known it is calculated by the formula:
where SF is the safety factor
*MDI is the mean daily intake
*W is the body weight
*ADI is the acceptable daily intake | 1 | Applied and Interdisciplinary Chemistry |
p75NTR is a member of the tumor necrosis factor receptor superfamily. p75NTR/LNGFR was the first member of this large family of receptors to be characterized, that now contains about 25 receptors, including tumor necrosis factor 1 (TNFR1) and TNFR2, Fas, RANK, and CD40.
All members of the TNFR superfamily contain structurally related cysteine-rich modules in their ECDs. p75NTR is an unusual member of this family due to its propensity to dimerize rather than trimerize, because of its ability to act as a tyrosine kinase co-receptor, and because the neurotrophins are structurally unrelated to the ligands, which typically bind TNFR family members. Indeed, with the exception of p75NTR, essentially all members of the TNFR family preferentially bind structurally related trimeric Type II transmembrane ligands, members of the TNF ligand superfamily. | 1 | Applied and Interdisciplinary Chemistry |
As part of the post-September 11 drive towards increased capability in homeland security and public health preparedness, traditional GC–MS units with transmission quadrupole mass spectrometers, as well as those with cylindrical ion trap (CIT-MS) and toroidal ion trap (T-ITMS) mass spectrometers have been modified for field portability and near real-time detection of chemical warfare agents (CWA) such as sarin, soman, and VX. These complex and large GC–MS systems have been modified and configured with resistively heated low thermal mass (LTM) gas chromatographs that reduce analysis time to less than ten percent of the time required in traditional laboratory systems. Additionally, the systems are smaller, and more mobile, including units that are mounted in mobile analytical laboratories (MAL), such as those used by the United States Marine Corps Chemical and Biological Incident Response Force MAL and other similar laboratories, and systems that are hand-carried by two-person teams or individuals, much ado to the smaller mass detectors. Depending on the system, the analytes can be introduced via liquid injection, desorbed from sorbent tubes through a thermal desorption process, or with solid-phase micro extraction (SPME). | 0 | Theoretical and Fundamental Chemistry |
The following substances are known to be HNMT inhibitors: amodiaquine, chloroquine, dimaprit, etoprine, metoprine, quinacrine, SKF-91488, tacrine, and diphenhydramine. HNMT inhibitors may increase histamine levels in peripheral tissues and aggravate conditions associated with histamine excess, such as allergic rhinitis, urticaria, and peptic ulcer disease. the effect of HNMT inhibitors on brain function is not yet fully understood. Research suggests that using new inhibitors of HNMT to increase the levels of histamine in the brain could potentially contribute to improvements in the treatment of brain disorders. | 1 | Applied and Interdisciplinary Chemistry |
Optical sequencing is a single molecule DNA sequencing technique that follows sequence-by-synthesis and uses optical mapping technology. Similar to other single molecular sequencing approaches such as SMRT sequencing, this technique analyzes a single DNA molecule, rather than amplify the initial sample and sequence multiple copies of the DNA. During synthesis, fluorochrome-labeled nucleotides are incorporated through the use of DNA polymerases and tracked by fluorescence microscopy. This technique was originally proposed by David C. Schwartz and Arvind Ramanathan in 2003. | 1 | Applied and Interdisciplinary Chemistry |
Primary metabolites as defined by Kossel are components of basic metabolic pathways that are required for life. They are associated with essential cellular functions such as nutrient assimilation, energy production, and growth/development. They have a wide species distribution that span many phyla and frequently more than one kingdom. Primary metabolites include the basic building blocks of life: carbohydrates, lipids, amino acids, and nucleic acids.
Primary metabolites that are involved with energy production include respiratory and photosynthetic enzymes. Enzymes in turn are composed of amino acids and often non-peptidic cofactors that are essential for enzyme function. The basic structure of cells and of organisms are also composed of primary metabolites. These include cell membranes (e.g. phospholipids), cell walls (e.g. peptidoglycan, chitin), and cytoskeletons (proteins).
Primary metabolite enzymatic cofactors include members of the vitamin B family. Vitamin B1 as thiamine diphosphate is a coenzyme for pyruvate dehydrogenase, 2-oxoglutarate dehydrogenase, and transketolase which are all involved in carbohydrate metabolism. Vitamin B2 (riboflavin) is a constituent of FMN and FAD which are necessary for many redox reactions. Vitamin B3 (nicotinic acid or niacin), synthesized from tryptophan is a component of the coenzymes NAD and NADP which in turn are required for electron transport in the Krebs cycle, oxidative phosphorylation, as well as many other redox reactions. Vitamin B5 (pantothenic acid) is a constituent of coenzyme A, a basic component of carbohydrate and amino acid metabolism as well as the biosynthesis of fatty acids and polyketides. Vitamin B6 (pyridoxol, pyridoxal, and pyridoxamine) as pyridoxal 5′-phosphate is a cofactor for many enzymes especially transaminases involve in amino acid metabolism. Vitamin B12 (cobalamins) contain a corrin ring similar in structure to porphyrin and is an essential coenzyme for the catabolism of fatty acids as well for the biosynthesis of methionine.
DNA and RNA, which store and transmit genetic information, are composed of nucleic acid primary metabolites.
First messengers are signaling molecules that control metabolism or cellular differentiation. These signaling molecules include hormones and growth factors in turn are composed of peptides, biogenic amines, steroid hormones, auxins, gibberellins etc. These first messengers interact with cellular receptors which are composed of proteins. Cellular receptors in turn activate second messengers are used to relay the extracellular message to intracellular targets. These signaling molecules include the primary metabolites cyclic nucleotides, diacyl glycerol etc. | 1 | Applied and Interdisciplinary Chemistry |
Many former British colonies in the region have always been LHT, including Australia, New Zealand, Fiji, Kiribati, Solomon Islands, Tonga, and Tuvalu; and nations that were previously administered by Australia: Nauru and Papua New Guinea. | 0 | Theoretical and Fundamental Chemistry |
In the field of genomics, GeneCalling is an open-platform mRNA transcriptional profiling technique. The GeneCalling protocol measures levels of cDNA, which are correlated with gene expression levels of specific transcripts. Differences between gene expression in healthy tissues and disease or drug responsive tissues are examined and compared in this technology. The technique has been applied to the study of human tissues and plant tissues. | 1 | Applied and Interdisciplinary Chemistry |
Eventually, the periodic table was appreciated for its descriptive power and for finally systematizing the relationship between the elements, although such appreciation was not universal. In 1881, Mendeleev and Meyer had an argument via an exchange of articles in British journal Chemical News over priority of the periodic table, which included an article from Mendeleev, one from Meyer, one of critique of the notion of periodicity, and many more. In 1882, the Royal Society in London awarded the Davy Medal to both Mendeleev and Meyer for their work to classify the elements; although two of Mendeleevs predicted elements had been discovered by then, Mendeleevs predictions were not at all mentioned in the prize rationale.
Mendeleevs eka-aluminium was discovered in 1875 and became known as gallium; eka-boron and eka-silicium were discovered in 1879 and 1886, respectively, and were named scandium and germanium. Mendeleev was even able to correct some initial measurements with his predictions, including the first prediction of gallium, which matched eka-aluminium fairly closely but had a different density. Mendeleev advised the discoverer, French chemist Paul-Émile Lecoq de Boisbaudran, to measure the density again; de Boisbaudran was initially skeptical (not least because he thought Mendeleev was trying to take credit from him) but eventually admitted the correctness of the prediction. Mendeleev contacted all three discoverers; all three noted the close similarity of their discovered elements with Mendeleevs predictions, with the last of them, German chemist Clemens Winkler, admitting this suggestion was not first made by Mendeleev or himself after the correspondence with him, but by a different person, German chemist Hieronymous Theodor Richter. Some contemporary chemists were not convinced by these discoveries, noting the dissimilarities between the new elements and the predictions or claiming those similarities that did exist were coincidental. However, success of Mendeleevs predictions helped spread the word about his periodic table. Later, chemists used the successes of these Mendeleevs predictions to justify his table.
By 1890, Mendeleev's periodic table had been universally recognized as a piece of basic chemical knowledge. Apart from his own correct predictions, a number of aspects may have contributed to this, such as the correct accommodation of many elements whose atomic weights were thought to have wrong values but were later corrected. The debate on the position of the rare-earth metals helped spur the discussion about the table as well. In 1889, Mendeleev noted at the Faraday Lecture to the Royal Institution in London that he had not expected to live long enough "to mention their discovery to the Chemical Society of Great Britain as a confirmation of the exactitude and generality of the periodic law". | 1 | Applied and Interdisciplinary Chemistry |
Water waves on a mean flow (so a wave in a moving medium) experience a Doppler shift. Suppose the dispersion relation for a non-moving medium is:
with k the wavenumber. Then for a medium with mean velocity vector V, the dispersion relationship with Doppler shift becomes:
where k is the wavenumber vector, related to k as: k = |k|. The dot product k•V is equal to: k•V = kV cos α, with V the length of the mean velocity vector V: V = |V|. And α the angle between the wave propagation direction and the mean flow direction. For waves and current in the same direction, k•V=kV. | 1 | Applied and Interdisciplinary Chemistry |
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