text stringlengths 105 4.57k | label int64 0 1 | label_text stringclasses 2 values |
|---|---|---|
The high short-term radioactivity of spent nuclear fuel is primarily from fission products with short half-life.
The radioactivity in the fission product mixture is mostly due to short-lived isotopes such as I and Ba, after about four months Ce, Zr/Nb and Sr constitute the largest contributors, while after about two or three years the largest share is taken by Ce/Pr, Ru/Rh and Pm.
Note that in the case of a release of radioactivity from a power reactor or used fuel, only some elements are released. As a result, the isotopic signature of the radioactivity is very different from an open air nuclear detonation where all the fission products are dispersed. | 0 | Theoretical and Fundamental Chemistry |
In a method termed magnetofection, DNA is complexed to magnetic particles, and a magnet is placed underneath the tissue culture dish to bring DNA complexes into contact with a cell monolayer. | 1 | Applied and Interdisciplinary Chemistry |
Succinic semialdehyde (SSA) is a GABA metabolite. It is formed from GABA by the action of GABA transaminase (4-aminobutyrate aminotransferase) and further oxidised to become succinic acid, which enters TCA cycle. SSA is oxidized into succinic acid by the enzyme succinic semialdehyde dehydrogenase, which uses NAD as a cofactor. When the oxidation of succinic semialdehyde to succinic acid is impaired, accumulation of succinic semialdehyde takes place which leads to succinic semialdehyde dehydrogenase deficiency. | 1 | Applied and Interdisciplinary Chemistry |
A significant task, regularly carried out by CSMBLM since 1970, is the external assessment of the performance quality of all medical biochemistry laboratories in the Republic of Croatia. The external evaluation programs are updated and continually expanded according to the needs of the profession and in line with the European organizations for labor quality assessment (EQAL). Assessment results are the basis for the rating of medical laboratories carried out by the Croatian Chamber of Medical Biochemists.
In this way CSMBLM provides continuous professional and advisory help in harmonization and evaluation of laboratory results at national and international level for medical biochemistry laboratories and all other laboratories which work in a field of laboratory medicine. | 1 | Applied and Interdisciplinary Chemistry |
One of the key classifications is between traditional small molecule drugs; usually derived from chemical synthesis and biological medical products; which include recombinant proteins, vaccines, blood products used therapeutically (such as IVIG), gene therapy, and cell therapy (for instance, stem cell therapies).
Pharmaceuticals or drugs or medicines are classified into various other groups besides their origin on the basis of pharmacological properties like mode of action and their pharmacological action or activity, such as by chemical properties, mode or route of administration, biological system affected, or therapeutic effects. An elaborate and widely used classification system is the Anatomical Therapeutic Chemical Classification System (ATC system). The World Health Organization keeps a list of essential medicines.
A sampling of classes of medicine includes:
# Antipyretics: reducing fever (pyrexia/pyresis)
# Analgesics: reducing pain (painkillers)
# Antimalarial drugs: treating malaria
# Antibiotics: inhibiting germ growth
# Antiseptics: prevention of germ growth near burns, cuts,and wounds
# Mood stabilizers: lithium and valproate
# Hormone replacements: Premarin
# Oral contraceptives: Enovid, "biphasic" pill, and "triphasic" pill
# Stimulants: methylphenidate, amphetamine
# Tranquilizers: meprobamate, chlorpromazine, reserpine, chlordiazepoxide, diazepam, and alprazolam
# Statins: lovastatin, pravastatin, and simvastatin
Pharmaceuticals may also be described as "specialty", independent of other classifications, which is an ill-defined class of drugs that might be difficult to administer, require special handling during administration, require patient monitoring during and immediately after administration, have particular regulatory requirements restricting their use, and are generally expensive relative to other drugs. | 1 | Applied and Interdisciplinary Chemistry |
Several strategies have been proposed as a way to protect those who are at greatest risk of occupational exposure to PFAS, including exposure monitoring, regular blood testing, and the use of PFAS-free alternatives. For example, fluorine-free firefighting foam and plant-based ski wax contain no PFAS and greatly reduce the occupational hazards associated with certain professions. | 0 | Theoretical and Fundamental Chemistry |
* The Tishchenko reaction of acetaldehyde gives the commercially important solvent ethyl acetate. The reaction is catalyzed by aluminium alkoxides.
* The Tishchenko reaction is used to obtain isobutyl isobutyrate, a specialty solvent.
* Hydroxypivalic acid neopentyl glycol ester is produced by a Tishchenko reaction from hydroxypivaldehyde in the presence of a basic catalyst (e.g., aluminium oxide).
* The Tishchenko reaction of paraformaldehyde in the presence of aluminum methylate or magnesium methylate forms methyl formate.
* Paraformaldehyde reacts with boric acid to form methyl formate. The key step in the reaction mechanism for this reaction is a 1,3-hydride shift in the hemiacetal intermediate formed from two successive nucleophilic addition reactions, the first one from the catalyst. The hydride shift regenerates the alkoxide catalyst. | 0 | Theoretical and Fundamental Chemistry |
In the late 18th century, right-hand traffic started to be introduced in the United States of America based on teamsters use of large freight wagons pulled by several pairs of horses and without a drivers seat; the (typically right-handed) postilion held his whip in his right hand and thus sat on the left rear horse, and therefore preferred other wagons passing on the left so that he would have a clear view of other vehicles. The first keep-right law for driving in the United States was passed in 1792 and applied to the Philadelphia and Lancaster Turnpike. Massachusetts formalized RHT in 1821. However, the National Road was LHT until 1850, "long after the rest of the country had settled on the keep-right convention". Today the United States is RHT except the United States Virgin Islands, which is LHT like many neighbouring islands.
Some special-purpose vehicles in the United States, like certain postal service trucks, garbage trucks, and parking-enforcement vehicles, are built with the driver's seat on the right for safer and easier access to the curb. A common example is the Grumman LLV, which is used nationwide by the US Postal Service and by Canada Post. | 0 | Theoretical and Fundamental Chemistry |
The physical reason for the anomeric effect is not completely understood. Several, in part conflicting, explanations have been offered and the topic is still not settled. | 0 | Theoretical and Fundamental Chemistry |
The LTFT facility Pearl GTL at Ras Laffan, Qatar, is the second largest FT plant in the world after Sasol's Secunda plant in South Africa. It uses cobalt catalysts at 230 °C, converting natural gas to petroleum liquids at a rate of , with additional production of of oil equivalent in natural gas liquids and ethane.
Another plant in Ras Laffan, called Oryx GTL, has been commissioned in 2007 with a capacity of . The plant utilizes the Sasol slurry phase distillate process, which uses a cobalt catalyst. Oryx GTL is a joint venture between QatarEnergy and Sasol. | 0 | Theoretical and Fundamental Chemistry |
In sedimentology, winnowing is the natural removal of fine material from a coarser sediment by wind or flowing water. Once a sediment has been deposited, subsequent changes in the speed or direction of wind or water flowing over it can agitate the grains in the sediment and allow the preferential removal of the finer grains. This action can improve the sorting and increase the mean grain size of a sediment after it has been deposited.
The term winnowing is from the analogous process for the agricultural separation of wheat from chaff. | 0 | Theoretical and Fundamental Chemistry |
is a Japanese chemist and Nobel Prize Laureate (2010), who first published the Suzuki reaction, the organic reaction of an aryl- or vinyl-boronic acid with an aryl- or vinyl-halide catalyzed by a palladium(0) complex, in 1979. | 0 | Theoretical and Fundamental Chemistry |
RNA editing (also RNA modification) is a molecular process through which some cells can make discrete changes to specific nucleotide sequences within an RNA molecule after it has been generated by RNA polymerase. It occurs in all living organisms and is one of the most evolutionarily conserved properties of RNAs. RNA editing may include the insertion, deletion, and base substitution of nucleotides within the RNA molecule. RNA editing is relatively rare, with common forms of RNA processing (e.g. splicing, 5-capping, and 3-polyadenylation) not usually considered as editing. It can affect the activity, localization as well as stability of RNAs, and has been linked with human diseases.
RNA editing has been observed in some tRNA, rRNA, mRNA, or miRNA molecules of eukaryotes and their viruses, archaea, and prokaryotes. RNA editing occurs in the cell nucleus, as well as within mitochondria and plastids. In vertebrates, editing is rare and usually consists of a small number of changes to the sequence of the affected molecules. In other organisms, such as squids, extensive editing (pan-editing) can occur; in some cases the majority of nucleotides in an mRNA sequence may result from editing. More than 160 types of RNA modifications have been described so far.
RNA-editing processes show great molecular diversity, and some appear to be evolutionarily recent acquisitions that arose independently. The diversity of RNA editing phenomena includes nucleobase modifications such as cytidine (C) to uridine (U) and adenosine (A) to inosine (I) deaminations, as well as non-template nucleotide additions and insertions. RNA editing in mRNAs effectively alters the amino acid sequence of the encoded protein so that it differs from that predicted by the genomic DNA sequence. | 1 | Applied and Interdisciplinary Chemistry |
Chemical imaging has been implemented for mid-infrared, near-infrared spectroscopy and Raman spectroscopy. As with their bulk spectroscopy counterparts, each imaging technique has particular strengths and weaknesses, and are best suited to fulfill different needs. | 0 | Theoretical and Fundamental Chemistry |
In 1905, Burgess and Holt observed that fusing mixtures of boric oxide and sodium carbonate yielded on cooling two crystalline compounds with definite compositions, consistent with anhydrous borax (which can be written ) and sodium octaborate (which can be written ). | 0 | Theoretical and Fundamental Chemistry |
Most sulfilimines are N-substituted with electron-withdrawing groups. These compounds are typically prepared by oxidation of thioethers with electrophilic amine reagents, such as chloramine-T in the presence of a base:
An alternative route involves reactions of electrophilic sulfur compounds with amines. The imidosulfonium reagents provide a source of "", which are attacked by amines. | 0 | Theoretical and Fundamental Chemistry |
Sulfuric acid (American spelling and the preferred IUPAC name) or sulphuric acid (Commonwealth spelling), known in antiquity as oil of vitriol, is a mineral acid composed of the elements sulfur, oxygen, and hydrogen, with the molecular formula . It is a colorless, odorless, and viscous liquid that is miscible with water.
Pure sulfuric acid does not occur naturally due to its strong affinity to water vapor; it is hygroscopic and readily absorbs water vapor from the air. Concentrated sulfuric acid is highly corrosive towards other materials, from rocks to metals, since it is an oxidant with powerful dehydrating properties. Phosphorus pentoxide is a notable exception in that it is not dehydrated by sulfuric acid but, to the contrary, dehydrates sulfuric acid to sulfur trioxide. Upon addition of sulfuric acid to water, a considerable amount of heat is released; thus, the reverse procedure of adding water to the acid should not be performed since the heat released may boil the solution, spraying droplets of hot acid during the process. Upon contact with body tissue, sulfuric acid can cause severe acidic chemical burns and even secondary thermal burns due to dehydration. Dilute sulfuric acid is substantially less hazardous without the oxidative and dehydrating properties; however, it should still be handled with care for its acidity.
Sulfuric acid is a very important commodity chemical; a country's sulfuric acid production is a good indicator of its industrial strength. Many methods for its production are known, including the contact process, the wet sulfuric acid process, and the lead chamber process. Sulfuric acid is also a key substance in the chemical industry. It is most commonly used in fertilizer manufacture but is also important in mineral processing, oil refining, wastewater processing, and chemical synthesis. It has a wide range of end applications, including in domestic acidic drain cleaners, as an electrolyte in lead-acid batteries, in dehydrating a compound, and in various cleaning agents.
Sulfuric acid can be obtained by dissolving sulfur trioxide in water. | 0 | Theoretical and Fundamental Chemistry |
In spectroscopy, collision-induced absorption and emission refers to spectral features generated by inelastic collisions of molecules in a gas. Such inelastic collisions (along with the absorption or emission of photons) may induce quantum transitions in the molecules, or the molecules may form transient supramolecular complexes with spectral features different from the underlying molecules. Collision-induced absorption and emission is particularly important in dense gases, such as hydrogen and helium clouds found in astronomical systems.
Collision-induced absorption and emission is distinguished from collisional broadening in spectroscopy in that collisional broadening comes from elastic collisions of molecules, whereas collision-induced absorption and emission is an inherently inelastic process. | 0 | Theoretical and Fundamental Chemistry |
The survival of these bacteria is dependent on the physiochemical conditions of their environment. Although they are sensitive to certain factors such as quality of inorganic substrate, they are able to thrive under some of the most inhospitable conditions in the world, such as temperatures above 110 degrees Celsius and below 2 pH. The most important requirement for chemolithotropic life is an abundant source of inorganic compounds, which provide a suitable electron donor in order to fix CO and produce the energy the microorganism needs to survive. Since chemosynthesis can take place in the absence of sunlight, these organisms are found mostly around hydrothermal vents and other locations rich in inorganic substrate.
The energy obtained from inorganic oxidation varies depending on the substrate and the reaction. For example, the oxidation of hydrogen sulfide to elemental sulfur by ½O produces far less energy (50 kcal/mol or 210 kJ/mol) than the oxidation of elemental sulfur to sulfate (150 kcal/mol or 627 kJ/mol) by 3/2 O,. The majority of lithotrophs fix carbon dioxide through the Calvin cycle, an energetically expensive process. For some low-energy substrates, such as ferrous iron, the cells must cull through large amounts of inorganic substrate to secure just a small amount of energy. This makes their metabolic process inefficient in many places and hinders them from thriving. | 1 | Applied and Interdisciplinary Chemistry |
Mariotte's bottle is a device that delivers a constant rate of flow from closed bottles or tanks. It is named after French physicist Edme Mariotte (1620-1684). A picture of a bottle with a gas inlet is shown in the works of Mariotte, but this construction was made to show the effect of outside pressure on mercury level inside the bottle. It further misses a siphon or an outlet for the liquid. | 1 | Applied and Interdisciplinary Chemistry |
Changes in the regulation of gene networks are a common mechanism for prokaryotic evolution. An example of the effects of different regulatory environments for homologous proteins is the DNA-binding protein OmpR, which is involved in response to osmotic stress in E. coli but is involved in response to acidic environments in the close relative Salmonella Typhimurium. | 1 | Applied and Interdisciplinary Chemistry |
In engineering, the Moody chart or Moody diagram (also Stanton diagram) is a graph in non-dimensional form that relates the Darcy–Weisbach friction factor f, Reynolds number Re, and surface roughness for fully developed flow in a circular pipe. It can be used to predict pressure drop or flow rate down such a pipe. | 1 | Applied and Interdisciplinary Chemistry |
The Hedgehog protein family is involved in induction of cell types and the creation of tissue boundaries and patterning and are found in all bilateral organisms. Hedgehog proteins were first discovered and studied in Drosophila. Hedgehog proteins produce key signals for the establishment of limb and body plan of fruit flies as well as homeostasis of adult tissues, involved in late embryogenesis and metamorphosis. At least three "Drosophila" hedgehog homologs have been found in vertebrates: sonic hedgehog, desert hedgehog, and Indian hedgehog. Sonic hedgehog (SHH) has various roles in vertebrae development, mediating signaling and regulating the organization of central nervous system, limb, and somite polarity. Desert hedgehog (DHH) is expressed in the Sertoli cells involved in spermatogenesis. Indian hedgehog (IHH) is expressed in the gut and cartilage, important in postnatal bone growth. | 1 | Applied and Interdisciplinary Chemistry |
Complexes with η-allyl ligands (classified as X-type ligands) are also known. One example is CpFe(CO)(η-CH), in which only the methylene group is attached to the Fe centre (i.e., it has the connectivity [Fe]–CH–CH=CH). As is the case for many other η-allyl complexes, the monohapticity of the allyl ligand in this species is enforced by the 18-electron rule, since CpFe(CO)(η-CH) is already an 18-electron complex, while an η-allyl ligand would result in an electron count of 20 and violate the 18-electron rule. Such complexes can convert to the η-allyl derivatives by dissociation of a neutral (two-electron) ligand L. For CpFe(CO)(η-CH), dissociation of L = CO occurs under photochemical conditions:
: CpFe(CO)(η-CH) → CpFe(CO)(η-CH) + CO | 0 | Theoretical and Fundamental Chemistry |
Gelbart's early interest in science was inspired by his time as an undergraduate researcher in the molecular spectroscopy group of William Klemperer at Harvard. As a graduate student at the University of Chicago, with his mentors Stuart A. Rice, Karl Freed, and Joshua Jortner, he developed the modern theory of non-radiative processes ("radiationless transitions") in molecular photophysics. He was a US National Science Foundation/NATO Postdoctoral Fellow at the, University of Paris in 1971, and a Miller Institute Postdoctoral Fellow at UC Berkeley in 1972, during which time he switched fields and formulated a general theory of collision-induced optical properties of simple fluids.
He was appointed Assistant Professor of Chemistry, at UC Berkeley in 1972, continuing his researches on the quantum mechanical theory of molecular spectroscopy and on the statistical mechanical theory of intermolecular and multiple light scattering in liquids away from and near their critical points. He moved to UCLA as Associate Professor of Chemistry in 1975, and was promoted to full Professor in 1979 and to Distinguished Professor in 1999. He was Chair of the Department of Chemistry and Biochemistry at UCLA from 2000-2004 and has been a member of UCLA's California NanoSystems Institute since 2004 and of its Molecular Biology Institute from 2008.
At UCLA he became a leader in the then-emerging fields of "complex fluids" and " soft matter physics". Shortly after moving there he began a 40-year collaboration with Avinoam Ben-Shaul on statistical-thermodynamic models of liquid crystal systems, polymer and polyelectrolyte (in particular, DNA) solutions, and colloidal suspensions, and on the self-assembly theory of micelles, surfactant monolayers, and biological membranes.
During a sabbatical year in 1998-99 at the Institute for Theoretical Physics in UC Santa Barbara and at the Curie Institute in Paris, Gelbart became deeply intrigued by viruses and over the course of the next several years, with his UCLA colleague Charles Knobler, established a laboratory to investigate simple viruses outside their hosts and isolated in test tubes. Early results included: the first measurement of pressure inside DNA viruses, establishing that it is as high as tens of atmospheres depending on genome length and ambient salt concentrations; and the demonstration that capsid proteins from certain viruses are capable of complete in vitro packaging of a broad range of lengths of heterologous RNA. This work, along with that of several other groups in the United States and Europe, helped launch the field of "physical virology". Most recently he moved his viruses from test tubes to host cells, and from wildtype viruses to artificial viruses and virus-like particles, engineered for purposes of delivering self-replicating RNA genes, RNA vaccines, and therapeutic microRNA to targeted mammalian cells. | 0 | Theoretical and Fundamental Chemistry |
The following individuals have held the position of President of this organization.
* 1871: David Thomas
* 1872–1874: Rossiter Worthington Raymond
* 1875: Alexander Lyman Holley
* 1876: Abram Stevens Hewitt
* 1877: Thomas Sterry Hunt
* 1878–1879: Eckley Brinton Coxe
* 1880: William Powell Shinn
* 1881: William Metcalf
* 1882: Richard Pennefather Rothwell
* 1883: Robert Woolston Hunt
* 1884–1885: James Cooper Bayles
* 1886: Robert Hallowell Richards
* 1887: Thomas Egleston
* 1888: William Bleeker Potter
* 1889: Richard Pearce
* 1890: Abram Stevens Hewitt
* 1891–1892: John Birkinbine
* 1893: Henry Marion Howe
* 1894: John Fritz
* 1895: Joseph D. Weeks
* 1896: Edmund Gybbon Spilsbury
* 1897: Thomas Messinger Drown
* 1898: Charles Kirchhoff
* 1899–1900: James Douglas
* 1901–1902: Eben Erskine Olcott
* 1903: Albert Reid Ledoux
* 1904–1905: James Gayley
* 1906: Robert Woolston Hunt
* 1907–1908: John Hays Hammond
* 1909–1910: David William Brunton
* 1911: Charles Kirchhoff
* 1912: James Furman Kemp
* 1913: Charles Frederic Rand
* 1914: Benjamin Bowditch Thayer
* 1915: William Lawrence Saunders
* 1916: Louis Davidson Ricketts
* 1917: Philip North Moore
* 1918: Sidney Johnston Jennings
* 1919: Horace Vaughn Winchell
* 1920: Herbert Hoover
* 1921: Edwin Ludlow
* 1922: Arthur Smith Dwight
* 1923: Edward Payson Mathewson
* 1924: William Kelly
* 1925: John van Wicheren Reynders
* 1926: Samuel A. Taylor
* 1927: Everette Lee DeGolyer
* 1928: George Otis Smith
* 1929: Frederick Worthen Bradley
* 1930: William Hastings Bassett
* 1931: Robert Emmet Tally
* 1932: Scott Turner
* 1933: Frederick Mark Becket
* 1934: Howard Nicholas Eavenson
* 1935: Henry Andrew Buehler
* 1936: John Meston Lovejoy
* 1937: Rolland Craten Allen
* 1938: Daniel Cowan Jackling
* 1939: Donald Burton Gillies
* 1940: Herbert George Moulton
* 1941: John Robert Suman
* 1942: Eugene McAuliffe
* 1943: Champion Herbert Mathewson
* 1944: Chester Alan Fulton
* 1945: Harvey Seeley Mudd
* 1946: Louis S. Cates
* 1947: Clyde Williams
* 1948: William Embry Wrather
* 1949: Lewis Emanuel Young
* 1950: Donald Hamilton McLaughlin
* 1951: Willis McGerald Peirce
* 1952: Michael Lawrence Haider
* 1953: Andrew Fletcher
* 1954: Leo Frederick Reinartz
* 1955: Henry DeWitt Smith
* 1956: Carl Ernest Reistle Jr.
* 1957: Grover Justine Holt
* 1958: Augustus Braun Kinzel
* 1959: Howard Carter Pyle
* 1960: Joseph Lincoln Gillson
* 1961: Ronald Russel McNaughton
* 1962: Lloyd E. Elkins
* 1963: Roger Vern Pierce
* 1964: Karl Leroy Fetters
* 1965: Thomas Corwin Frick
* 1966: William Bishop Stephenson
* 1967: Walter R. Hibbard Jr.
* 1968: John Robertson McMillan
* 1969: James Boyd
* 1970: John C. Kinnear
* 1971: John Smith Bell
* 1972: Dennis L. McElroy
* 1973: James B. Austin
* 1974: Wayne E. Glenn
* 1975: James D. Reilly
* 1976: Julius J. Harwood
* 1977: H. Arthur Nedom
* 1978: Wayne L. Dowdey
* 1979: William H. Wise
* 1980: M. Scott Kraemer
* 1981: Robert H. Merrill
* 1982: Harold W. Paxton
* 1983: Edward E. Runyan
* 1984: Nelson Severinghaus, Jr.
* 1985: Norman T. Mills
* 1986: Arlen L. Edgar
* 1987: Alan Lawley
* 1988: Thomas V. Falkie
* 1989: Howard N. Hubbard, Jr.
* 1990: Donald G. Russell
* 1991: Milton E. Wadsworth
* 1992: Roshan B. Bhappu
* 1993: G. Hugh Walker
* 1994: Noel D. Rietman
* 1995: Frank V. Nolfi, Jr.
* 1996: Donald W. Gentry
* 1997: Leonard G. Nelson
* 1998: Roy H. Koerner
* 1999: Paul G. Campbell, Jr.
* 2000: Robert E. Murray
* 2001: Grant P. Schneider
* 2002: George H. Sawyer
* 2003: Robert H. Wagoner
* 2004: Robert C. Freas
* 2005: Alan W. Cramb
* 2006: James R. Jorden
* 2007: Dan J. Thoma
* 2008: Michael Karmis
* 2009: Ian Sadler
* 2010: DeAnn Craig
* 2011: Brajendra Mishra
* 2012: George W. Luxbacher
* 2013: Dale Heinz
* 2014: Behrooz Fattahi
* 2015: Garry W. Warren
* 2016: Nikhil Trivedi
* 2017: John G. Speer | 1 | Applied and Interdisciplinary Chemistry |
Pulse radiolysis is a recent method of initiating fast reactions to study reactions occurring on a timescale faster than approximately one hundred microseconds, when simple mixing of reagents is too slow and other methods of initiating reactions have to be used.
The technique involves exposing a sample of material to a beam of highly accelerated electrons, where the beam is generated by a linac. It has many applications. It was developed in the late 1950s and early 1960s by John Keene in Manchester and Jack W. Boag in London. | 0 | Theoretical and Fundamental Chemistry |
* Biology 12: a student resource, R. Prior.
* Lehmann, M. (2018). Endocrine and physiological regulation of neutral fat storage in Drosophila. Molecular and Cellular Endocrinology, 461, 165–177.
* Christoph Heier, Ronald P Kühnlein, Triacylglycerol Metabolism in Drosophila melanogaster, Genetics, Volume 210, Issue 4, 1 December 2018, Pages 1163–1184, | 1 | Applied and Interdisciplinary Chemistry |
Gaseous ionization detectors collect and record the electrons freed from gaseous atoms and molecules by the interaction of radiation released by the source. A voltage potential is applied between two electrodes within a sealed system. Since the gaseous atoms are ionized after they interact with radiation they are attracted to the anode which produces a signal. It is important to vary the applied voltage such that the response falls within a critical proportional range. | 0 | Theoretical and Fundamental Chemistry |
* Principe, Lawrence and William Newman. Alchemy Tried in the Fire: Starkey, Boyle, and the Fate of Helmontian Chymistry. University of Chicago Press, 2002. | 1 | Applied and Interdisciplinary Chemistry |
β-Hydroxybutyric acid is the precursor to polyesters, which are biodegradable plastics. This polymer, poly(3-hydroxybutyrate), is also naturally produced by the bacteria Alcaligenes eutrophus.
β-Hydroxybutyrate can be extracted from poly(3-hydroxybutyrate) by acid hydrolysis.
The concentration of in blood plasma is measured through a test that uses β-hydroxybutyrate dehydrogenase, with NAD as an electron-accepting cofactor. The conversion of to acetoacetate, which is catalyzed by this enzyme, reduces the NAD to NADH, generating an electrical change; the magnitude of this change can then be used to extrapolate the amount of in the sample. | 1 | Applied and Interdisciplinary Chemistry |
Models predict a seasonal nitrogen cycle on Pluto and observations by New Horizons appear to support this. | 0 | Theoretical and Fundamental Chemistry |
Electron-counting rules are used to predict the preferred electron count for molecules. The octet rule, the 18-electron rule, and Hückels 4n + 2 pi-electron rule are proven to be useful in predicting the molecular stability. Wades rules were formulated to explain the electronic requirement of monopolyhedral borane clusters. The Jemmis mno rules are an extension of Wade's rules, generalized to include condensed polyhedral boranes as well.
The first condensed polyhedral borane, , is formed by sharing four vertices between two icosahedra. According to Wades n + 1 rule for n-vertex closo structures, should have a charge of +2 (n + 1 = 20 + 1 = 21 pairs required; 16 BH units provide 16 pairs; four shared boron atoms provide 6 pairs; thus 22 pairs are available). To account for the existence of as a neutral species, and to understand the electronic requirement of condensed polyhedral clusters, a new variable, m, was introduced and corresponds to the number of polyhedra (sub-clusters). In Wades n + 1 rule, the 1 corresponds to the core bonding molecular orbital (BMO) and the n corresponds to the number of vertices, which in turn is equal to the number of tangential surface BMOs. If m polyhedra condense to form a macropolyhedron, m core BMOs will be formed. Thus the skeletal electron pair (SEP) requirement of closo-condensed polyhedral clusters is m + n.
Single-vertex sharing is a special case where each subcluster needs to satisfy Wades rule separately. Let a and b be the number of vertices in the subclusters including the shared atom. The first cage requires a + 1 and the second cage requires b + 1 SEPs. Therefore, a total of a + b + 2 or a + b + m SEPs are required; but a + b = n + 1, as the shared atom is counted twice. The rule can be modified to m + n + 1, or generally m + n + o, where o corresponds to the number of single-vertex sharing condensations. The rule can be made more general by introducing a variable, p, corresponding to the number of missing vertices, and q', the number of caps. As such, the generalized Jemmis rule can be stated as follows:
:The SEP requirement of condensed polyhedral clusters is m + n + o + p − q, where m is the number of subclusters, n is the number of vertices, o is the number of single-vertex shared condensations, p is the number of missing vertices and q is the number of caps. | 0 | Theoretical and Fundamental Chemistry |
Antiretroviral drugs are medications for the treatment of infection by retroviruses, primarily HIV. Different classes of antiretroviral drugs act on different stages of the HIV life cycle. Combination of several (typically three or four) antiretroviral drugs is known as highly active antiretroviral therapy (HAART). | 1 | Applied and Interdisciplinary Chemistry |
K values are used, among others, to assess the environmental fate of persistent organic pollutants. Chemicals with high partition coefficients, for example, tend to accumulate in the fatty tissue of organisms (bioaccumulation). Under the Stockholm Convention, chemicals with a log K greater than 5 are considered to bioaccumulate.
Furthermore, the parameter plays an important role in drug research (Rule of Five) and toxicology. Ernst Overton and Hans Meyer discovered as early as 1900 that the efficacy of an anaesthetic increased with increasing K value (the so-called Meyer-Overton rule).
K values also provide a good estimate of how a substance is distributed within a cell between the lipophilic biomembranes and the aqueous cytosol. | 0 | Theoretical and Fundamental Chemistry |
Currently there are no existing compounds that can mimic the peptide bond of proline to other amino acids while maintaining only a cis or trans configuration because most mimics found will eventually change from one isomer to another. This makes research on the direct effect of each of the isomers on biological mechanisms more difficult. Also, the actual isomerization of proline is a slow process, meaning that any studying of the effects of the different isomers of proline takes a large amount of time to complete. | 0 | Theoretical and Fundamental Chemistry |
In fluid dynamics, the Boussinesq approximation for water waves is an approximation valid for weakly non-linear and fairly long waves. The approximation is named after Joseph Boussinesq, who first derived them in response to the observation by John Scott Russell of the wave of translation (also known as solitary wave or soliton). The 1872 paper of Boussinesq introduces the equations now known as the Boussinesq equations.
The Boussinesq approximation for water waves takes into account the vertical structure of the horizontal and vertical flow velocity. This results in non-linear partial differential equations, called Boussinesq-type equations, which incorporate frequency dispersion (as opposite to the shallow water equations, which are not frequency-dispersive). In coastal engineering, Boussinesq-type equations are frequently used in computer models for the simulation of water waves in shallow seas and harbours.
While the Boussinesq approximation is applicable to fairly long waves – that is, when the wavelength is large compared to the water depth – the Stokes expansion is more appropriate for short waves (when the wavelength is of the same order as the water depth, or shorter). | 1 | Applied and Interdisciplinary Chemistry |
One of the most successful labourers in the science of hydrodynamics at this period was Pierre-Louis-Georges du Buat. Following in the steps of the Abbé Charles Bossut (Nouvelles Experiences sur la résistance des fluides, 1777), he published, in 1786, a revised edition of his Principes dhydraulique', which contains a satisfactory theory of the motion of fluids, founded solely upon experiments. Dubuat considered that if water were a perfect fluid, and the channels in which it flowed infinitely smooth, its motion would be continually accelerated, like that of bodies descending in an inclined plane. But as the motion of rivers is not continually accelerated, and soon arrives at a state of uniformity, it is evident that the viscosity of the water, and the friction of the channel in which it descends, must equal the accelerating force. Dubuat, therefore, assumed it as a proposition of fundamental importance that, when water flows in any channel or bed, the accelerating force which obliges it to move is equal to the sum of all the resistances which it meets with, whether they arise from its own viscosity or from the friction of its bed. This principle was employed by him in the first edition of his work, which appeared in 1779. The theory contained in that edition was founded on the experiments of others, but he soon saw that a theory so new, and leading to results so different from the ordinary theory, should be founded on new experiments more direct than the former, and he was employed in the performance of these from 1780 to 1783. The experiments of Bossut were made only on pipes of a moderate declivity, but Dubuat used declivities of every kind, and made his experiments upon channels of various sizes. | 1 | Applied and Interdisciplinary Chemistry |
During the roll bending process the pipe, extrusion, or solid is passed through a series of rollers (typically three) that apply pressure to the pipe gradually changing the bend radius in the pipe. The pyramid style roll benders have one moving roll, usually the top roll. Double pinch type roll benders have two adjustable rolls, usually the bottom rolls, and a fixed top roll. This method of bending causes very little deformation in the cross section of the pipe. This process is suited to producing coils of pipe as well as long gentle bends like those used in truss systems. | 1 | Applied and Interdisciplinary Chemistry |
The school has a research staff of approximately 120 individuals, and an academic staff of over 40. Current annual enrollment includes around 200 research students, and 450 taught postgraduate and undergraduate students.
EaStCHEM is the joint research school in chemistry between the Universities of Edinburgh and St Andrews. It has eight research groupings: Chemical Biology; Synthesis; Materials; Structural Chemistry; Chemical Physics; Biophysical Chemistry; Inorganic Chemistry; and Catalysis.
In the Research Assessment Exercise (RAE) 2008, the most in-depth analysis of research outputs for seven years, EaStCHEM, submitted 73% of all world leading outputs (4*) in Scotland and 12% of world leading outputs in all of the UK. From 31 submissions EastChem was the largest in UK Chemistry. EaStCHEM comes joint 4th in the Grade Point Average (GPA) metric, and first when staff numbers are factored in (the power ranking). | 1 | Applied and Interdisciplinary Chemistry |
Neosaxitoxin (NSTX) is included, as other saxitoxin-analogs, in a broad group of natural neurotoxic alkaloids, commonly known as the paralytic shellfish toxins (PSTs). The parent compound of PSTs, saxitoxin (STX), is a tricyclic perhydropurine alkaloid, which can be substituted at various positions, leading to more than 30 naturally occurring STX analogues. All of them are related imidazoline guanidinium derivatives. | 1 | Applied and Interdisciplinary Chemistry |
A multi-component reaction (or MCR), sometimes referred to as a "Multi-component Assembly Process" (or MCAP), is a chemical reaction where three or more compounds
react to form a single product. By definition, multicomponent reactions are those reactions whereby more than two reactants combine in a sequential manner to give highly selective products that retain majority of the atoms of the starting material. | 0 | Theoretical and Fundamental Chemistry |
In older plants and those receiving variable loadings, trickling filter beds are used where the settled sewage liquor is spread onto the surface of a bed made up of coke (carbonized coal), limestone chips or specially fabricated plastic media. Such media must have large surface areas to support the biofilms that form. The liquor is typically distributed through perforated spray arms. The distributed liquor trickles through the bed and is collected in drains at the base. These drains also provide a source of air which percolates up through the bed, keeping it aerobic. Biofilms of bacteria, protozoa and fungi form on the media’s surfaces and eat or otherwise reduce the organic content. The filter removes a small percentage of the suspended organic matter, while the majority of the organic matter supports microorganism reproduction and cell growth from the biological oxidation and nitrification taking place in the filter. With this aerobic oxidation and nitrification, the organic solids are converted into biofilm grazed by insect larvae, snails, and worms which help maintain an optimal thickness. Overloading of beds may increase biofilm thickness leading to anaerobic conditions and possible bioclogging of the filter media and ponding on the surface. | 1 | Applied and Interdisciplinary Chemistry |
A range of qualitative and quantitative tests have been developed to detect phosphate ions (PO) in solution. Such tests find use in industrial processes, scientific research, and environmental water monitoring. | 0 | Theoretical and Fundamental Chemistry |
The purpose of radiological emergency preparedness is to protect people from the effects of radiation exposure after a nuclear accident or bomb. Evacuation is the most effective protective measure. However, if evacuation is impossible or even uncertain, then local fallout shelters and other measures provide the best protection.
Zr) and/or involatiles is less for accident fallout than it is bomb fallout. A definitive report on Chernobyl is at [http://www.nea.fr/html/rp/chernobyl/allchernobyl.html] - Chapter 2, Table 1 lists the radioisotopes released in the fire. The percentage of the inventory which was released was controlled largely by how volatile the fission product is. Hence a greater proportion of xenon and iodine were released than of cerium and plutonium.
For the longer term response, a review of the methods that can be used to decontaminate an urban environment is provided in the scope report [http://www.icsu-scope.org/downloadpubs/scope50/chapter06.html Behaviour and Decontamination of Artificial Radionuclides in the Urban Environment]. Also see chapter four of the NEA reports [http://citeseer.ist.psu.edu/cache/papers/cs/28102/http:zSzzSzwww.nea.frzSzhtmlzSzrpzSzchernobylzSzchernobyl-1995.pdf/chernobyl-ten-years-on.pdf Chernobyl ten years on] and [http://www.nea.fr/html/rp/reports/2003/nea3508-chernobyl.pdf Chernobyl twenty years on] for details of how farming methods can be changed to reduce the impact of accident fallout.--> | 0 | Theoretical and Fundamental Chemistry |
Microarray image processing must correctly identify the regular grid of features within an image and independently quantify the fluorescence intensity for each feature. Image artefacts must be additionally identified and removed from the overall analysis. Fluorescence intensities directly indicate the abundance of each sequence, since the sequence of each probe on the array is already known.
The first steps of RNA-seq also include similar image processing; however, conversion of images to sequence data is typically handled automatically by the instrument software. The Illumina sequencing-by-synthesis method results in an array of clusters distributed over the surface of a flow cell. The flow cell is imaged up to four times during each sequencing cycle, with tens to hundreds of cycles in total. Flow cell clusters are analogous to microarray spots and must be correctly identified during the early stages of the sequencing process. In Roche’s pyrosequencing method, the intensity of emitted light determines the number of consecutive nucleotides in a homopolymer repeat. There are many variants on these methods, each with a different error profile for the resulting data. | 1 | Applied and Interdisciplinary Chemistry |
Indium(III) hydroxide is the chemical compound with the formula . Its prime use is as a precursor to indium(III) oxide, . It is sometimes found as the rare mineral dzhalindite.
__TOC__ | 0 | Theoretical and Fundamental Chemistry |
The continuum definition of surface free energy is the amount of reversible work performed to create new area of surface, expressed as:
In this definition the number of atoms at the surface is proportional to the area. Gibbs was the first to define another surface quantity, different from the surface free energy , that is associated with the reversible work per unit area needed to elastically stretch a pre-existing surface. In a continuum approach one can define a surface stress tensor that relates the work associated with the variation in , the total excess free energy of the surface due to a strain tensor
In general there is no change in area for shear, which means that for the second term on the right and , using the Kronecker delta. Cancelling the area then gives
called the Shuttleworth equation.
An alternative approach is an atomistic one, which defines all quantities in terms of the number of atoms, not continuum measures such as areas. This is related to the ideal of using Gibb's equimolar quantities rather than continuum numbers such as area, that is keeping the number of surface atoms constant. In this case the surface stress is defined as the derivative of the surface energy with strain, that is (deliberately using a different symbol)
This second definition is more convenient in many cases. A conventional liquid cannot sustain strains, so in the continuum definition the surface stress and surface energies are the same, whereas in the atomistic approach the surface stress is zero for a liquid. So long as care is taken the choice of the two does not matter, although this has been a little contentious in the literature. | 0 | Theoretical and Fundamental Chemistry |
Black phosphorus is the thermodynamically stable form of phosphorus at room temperature and pressure, with a heat of formation of −39.3 kJ/mol (relative to white phosphorus which is defined as the standard state). It was first synthesized by heating white phosphorus under high pressures (12,000 atmospheres) in 1914. As a 2D material, in appearance, properties, and structure, black phosphorus is very much like graphite with both being black and flaky, a conductor of electricity, and having puckered sheets of linked atoms.
Black phosphorus has an orthorhombic pleated honeycomb structure and is the least reactive allotrope, a result of its lattice of interlinked six-membered rings where each atom is bonded to three other atoms. In this structure, each phosphorus atom has five outer shell electrons. Black and red phosphorus can also take a cubic crystal lattice structure. The first high-pressure synthesis of black phosphorus crystals was made by the Nobel prize winner Percy Williams Bridgman in 1914. Metal salts catalyze the synthesis of black phosphorus.
Black phosphorus based sensors exhibit several superior qualities over traditional materials used in piezoelectric or resistive sensors. Characterized by its unique puckered honeycomb lattice structure, black phosphorus provides exceptional carrier mobility. This property ensures its high sensitivity and mechanical resilience, making it an intriguing candidate for sensor technology. | 0 | Theoretical and Fundamental Chemistry |
An estimated 26,000 U.S. sites are contaminated with PFASs. At least six million Americans are estimated to have drinking water containing PFASs above the safe limit published prior to 2022 by the U.S. Environmental Protection Agency (EPA). More than 200 million Americans are estimated to live in places where the tap water PFAS level (a combination of PFOA and PFOS levels) exceeds the 1 ppt (part per trillion) limit set in 2022 by the EPA.
, the states of California, Connecticut, Massachusetts, Michigan, Minnesota, New Hampshire, New Jersey, New York, Vermont, and Wisconsin had enforceable drinking water standards for between two and six types of PFAS. The six chemicals (termed by the Massachusetts Department of Environmental Protection as PFAS6) are measured either individually or summed as a group depending on the standard; they are:
* Perfluorooctanesulfonic acid (PFOS)
* Perfluorooctanoic acid (PFOA)
* Perfluorohexanesulfonic acid (PFHxS)
* Perfluorononanoic acid (PFNA)
* Perfluoroheptanoic acid (PFHpA)
* Perfluorodecanoic acid (PFDA)
EPA published non-enforceable drinking water health advisories for PFOA and PFOS in 2016. In March 2021 EPA announced that it would develop national drinking water standards for PFOA and PFOS. On December 27, 2021, EPA published a regulation requiring drinking water utilities to conduct monitoring for 29 compounds. The data are to be collected during 2023 to 2025. EPA will pay for the monitoring costs for small drinking water systems (those serving a population of 10,000 or fewer). The agency may use the monitoring data to develop additional regulations.
In mid-2021 EPA announced plans to revise federal wastewater regulations (effluent guidelines) for several industries that manufacture PFASs or use PFASs in fabricating various products.
In October 2021 EPA announced the PFAS Strategic Roadmap. It is a "whole-of-EPA" strategy and considers the full lifecycle of PFAS—including drinking water monitoring and risk assessment for PFOA and PFOS in biosolids (processed wastewater sludge used as fertilizer).
The EPA issued health advisories for four specific PFASs in June 2022, significantly lowering their safe threshold levels for drinking water. PFOA was reduced from 70 ppt to 0.004 ppt, while PFOS was reduced from 70 ppt to 0.02 ppt. GenX's safe levels were set at 10 ppt, while PFBS were set to 2000 ppt. While not enforceable, these health advisories are intended to be acted on by states in setting their own drinking water standards.
A formal EPA rule to add PFOA and PFAS as hazardous chemicals was first issued for comment in August 2022, which would require anyone discharging waste to monitor and restrict the release of these PFAS to set levels, and report when the wastewater exceeds it. It would also make grounds affected by high levels of PFIA or PFAS to be considered Superfund cleanup sites. The EPA formally established rules for these two chemicals.
EPA has listed recommended steps that consumers may take to reduce possible exposure to PFAS chemicals.
On 14 March 2023, EPA announced the proposed National Primary Drinking Water Regulation (NPDWR). This proposal includes new maximum contaminant levels (MCLs) in drinking water for six well-known PFAS: PFOA, PFOS, GenX, PFBS, PFNA, and PFHxS. While the proposal does not require any actions until its finalization, the EPA believes it will be implemented by late 2023. If these new restrictions are put into place, the EPA expects that they will prevent thousands of deaths and tens of thousands of PFAS-attributable illnesses. Along with legally enforceable MCLs, the EPA proposal will also require public water systems to actively monitor for the 6 PFAS, notify the public about the level of PFAS in the water supply, and take measures to reduce the level of PFAS in drinking water if they exceed the MCLs.
Between 2016 and 2021 the U.S. Geological Survey (USGS) tested tap water from 716 locations across the United States, and reported in 2023 that the PFAS levels exceeded the EPA advisories in approximately 75% of the samples from urban areas and in approximately 25% of the rural area samples.
In 2023, the American multinational 3M reached a US$10.3 billion settlement with a host of US public water systems to resolve water pollution claims tied to PFAS. Three other major chemicals companies – Chemours, DuPont and Corteva – have reached an agreement in principle for US$1.19 bn to settle claims they contaminated US public water systems with PFAS. | 0 | Theoretical and Fundamental Chemistry |
Deposits reduce the heat transfer in the boiler, reduce the flow rate and eventually block boiler tubes. Any non-volatile salts and minerals that will remain when the feedwater is evaporated must be removed, because they will become concentrated in the liquid phase and require excessive "blow-down" (draining) to prevent the formation of solid precipitates. Even worse are minerals that form scale. Therefore, the make-up water added to replace any losses of feedwater must be demineralized/deionized water, unless a purge valve is used to remove dissolved minerals. | 1 | Applied and Interdisciplinary Chemistry |
Encapsulin nanocompartments, or encapsulin protein cages, are spherical bacterial organelle-like compartments roughly 25-30 nm in diameter that are involved in various aspects of metabolism, in particular protecting bacteria from oxidative stress. Encapsulin nanocompartments are structurally similar to the HK97 bacteriophage and their function depends on the proteins loaded into the nanocompartment. The sphere is formed from 60 (for a 25 nm sphere) or 180 (for a 30 nm sphere) copies of a single protomer, termed encapsulin. Their structure has been studied in great detail using X-ray crystallography and cryo-electron microscopy.
A number of different types of proteins have been identified as being loaded into encapsulin nanocompartments. Peroxidases or proteins similar to ferritins are the two most common types of cargo proteins. While most encapsulin nanocompartments contain only one type of cargo protein, in some species two or three types of cargo proteins are loaded.
Encapsulins purified from Rhodococcus jostii can be assembled and disassembled with changes in pH. In the assembled state, the compartment enhances the activity of its cargo, a peroxidase enzyme. | 1 | Applied and Interdisciplinary Chemistry |
Nuclear chemistry is the sub-field of chemistry dealing with radioactivity, nuclear processes, and transformations in the nuclei of atoms, such as nuclear transmutation and nuclear properties.
It is the chemistry of radioactive elements such as the actinides, radium and radon together with the chemistry associated with equipment (such as nuclear reactors) which are designed to perform nuclear processes. This includes the corrosion of surfaces and the behavior under conditions of both normal and abnormal operation (such as during an accident). An important area is the behavior of objects and materials after being placed into a nuclear waste storage or disposal site.
It includes the study of the chemical effects resulting from the absorption of radiation within living animals, plants, and other materials. The radiation chemistry controls much of radiation biology as radiation has an effect on living things at the molecular scale. To explain it another way, the radiation alters the biochemicals within an organism, the alteration of the bio-molecules then changes the chemistry which occurs within the organism; this change in chemistry then can lead to a biological outcome. As a result, nuclear chemistry greatly assists the understanding of medical treatments (such as cancer radiotherapy) and has enabled these treatments to improve.
It includes the study of the production and use of radioactive sources for a range of processes. These include radiotherapy in medical applications; the use of radioactive tracers within industry, science and the environment, and the use of radiation to modify materials such as polymers.
It also includes the study and use of nuclear processes in non-radioactive areas of human activity. For instance, nuclear magnetic resonance (NMR) spectroscopy is commonly used in synthetic organic chemistry and physical chemistry and for structural analysis in macro-molecular chemistry. | 0 | Theoretical and Fundamental Chemistry |
Flubber, also commonly known as slime, is a non-Newtonian fluid, easily made from polyvinyl alcohol–based glues (such as white "school" glue) and borax. It flows under low stresses but breaks under higher stresses and pressures. This combination of fluid-like and solid-like properties makes it a Maxwell fluid. Its behaviour can also be described as being viscoplastic or gelatinous. | 1 | Applied and Interdisciplinary Chemistry |
Oxamic acid is an organic compound with the formula . It is a white, water-soluble solid. It is the monoamide of oxalic acid. Oxamic acid inhibits lactate dehydrogenase A. The active site of lactate dehydrogenase (LDH) is closed off once oxamic acid attaches to the LDH-NADH complex, effectively inhibiting it.
Oxamic acid also has applications in polymer chemistry. It increases the water solubility of certain polymers, including polyester, epoxide, and acrylic upon binding with them. | 1 | Applied and Interdisciplinary Chemistry |
This shell contains applications which are essential for problems involving group-subgroup relations between space groups. Given the space group types of G and H and their index, the program [http://www.cryst.ehu.es/cryst/subgroupgraph.html SUBGROUPGRAPH] provides graphs of maximal subgroups for a group-subgroup pair G > H, all the different subgroups H and their distribution into conjugacy classes. The Wyckoff position splitting rules for a group-subgroup pair are calculated by the program [http://www.cryst.ehu.es/cryst/wpsplit.html WYCKSPLIT]. | 0 | Theoretical and Fundamental Chemistry |
Bioelectrochemical reactors are finding an application in wastewater treatment settings. Current activated sludge processes are energy- and cost-inefficient due to sludge maintenance, aeration needs, and energy needs. By using a bioelectrochemical reactor that utilizes the concept of trickling filtering, these inefficiencies can be addressed. While processing wastewater using this reactor, nitrification, denitrification, and organic matter removal all take place simultaneously in both aerobic and anaerobic conditions using multiple different microbes located on the anode of the system. Though the processing parameters of the reactor affect the overall composition of each microbe, genus Geobacter and genus Desulfuromonas are frequently found in these applications. | 1 | Applied and Interdisciplinary Chemistry |
Since almost all adsorptive separation processes are dynamic -meaning, that they are running under flow - testing porous materials for those applications for their separation performance has to be tested under flow as well. Since separation processes run with mixtures of different components, measuring several breakthrough curves results in thermodynamic mixture equilibria - mixture sorption isotherms, that are hardly accessible with static manometric sorption characterization. This enables the determination of sorption selectivities in gaseous and liquid phase.
The determination of breakthrough curves is the foundation of many other processes, like the pressure swing adsorption. Within this process, the loading of one adsorber is equivalent to a breakthrough experiment. | 0 | Theoretical and Fundamental Chemistry |
Lactate can be used to produce a bioplastic called polylactic acid (PLA). The properties of PLA depend on the ratio of the two optical isomers of lactate (D-lactate and L-lactate). D-lactate is produced by mixed acid fermentation in E. coli. Early experiments engineered the E. coli strain RR1 to produce either one of the two optical isomers of lactate.
Later experiments modified the E. coli strain KO11, originally developed to enhance ethanol production. Scientists were able to increase the yield of D-lactate from fermentation by performing several deletions. | 1 | Applied and Interdisciplinary Chemistry |
The stereographic is the only projection that maps all circles on a sphere to circles on a plane. This property is valuable in planetary mapping where craters are typical features. The set of circles passing through the point of projection have unbounded radius, and therefore degenerate into lines. | 0 | Theoretical and Fundamental Chemistry |
Pipes, ducts and conduits are identification by the Australian Standard AS 1345—1995 “Identification of the contents of pipes, conduits and ducts” | 1 | Applied and Interdisciplinary Chemistry |
Geopolymer bonded wood composite (GWC) are similar and a green alternatives to cement bonded wood composites. These products are composed of geopolymer binder, wood fibers/ wood particles. Depending on the wood and geopolymer ratio in the material, the properties of the wood-geopolymer composite material vary. The main functions of wood in the composite material are weight reduction, reduction of thermal conductivity and the fixture function whereas the main functions of geopolymer are bonding of wood particles, improvement of fire resistance, providing mechanical strength, improvement of humidity resistance and protection against fungal and insect damages.
They serve similar functions and purposes like all other mineral bonded wood composites. The fact that the binder agent (geopolymer) are mostly produced from industrial residue and waste puts these materials at a greater advantage over other mineral bonded wood composites. However, most of the works under this topic remains at the research and development phase. Some of the core difficulties in production and commercialization of standardize product is the variation in the sources of the aluminosilicate binder and the cost involve in activating the binder. Currently, metakaolin binder remains as the one key source to produce or bind these products with huge variations in other sources of the binder such as slag, fly ash etc. | 0 | Theoretical and Fundamental Chemistry |
Anti-Cancer Agents in Medicinal Chemistry is a peer-reviewed academic journal covering the disciplines of medicinal chemistry and drug design relating to chemotherapeutic agents in cancer. It is published by Bentham Science Publishers and the editor-in-chief is Simone Carradori ("G. d'Annunzio" University of Chieti-Pescara). The journal covers developments in "medicinal chemistry and rational drug design for the discovery of anti-cancer agents" and publishes original research reports and review papers.
It is related to the journal Current Medicinal Chemistry and was established in 2001 as Current Medicinal Chemistry – Anti-Cancer Agents. The journal obtained its present title in 2006. | 1 | Applied and Interdisciplinary Chemistry |
Jeannette Elizabeth Brown (born May 13, 1934) is a retired American organic medicinal chemist, historian, and author. | 1 | Applied and Interdisciplinary Chemistry |
Other systems of drug classification exist, for example the Biopharmaceutics Classification System which determines a drugs' attributes by solubility and intestinal permeability. | 1 | Applied and Interdisciplinary Chemistry |
Electronic components that require clear transparency for light to exit or enter (photovoltaic panels and sensors) can be potted using acrylic resins that are cured using UV energy. The advantages are low VOC emissions and rapid curing.
Certain inks, coatings, and adhesives are formulated with photoinitiators and resins. When exposed to UV light, polymerization occurs, and so the adhesives harden or cure, usually within a few seconds. Applications include glass and plastic bonding, optical fiber coatings, the coating of flooring, UV coating and paper finishes in offset printing, dental fillings, and decorative fingernail "gels".
UV sources for UV curing applications include UV lamps, UV LEDs, and excimer flash lamps. Fast processes such as flexo or offset printing require high-intensity light focused via reflectors onto a moving substrate and medium so high-pressure Hg (mercury) or Fe (iron, doped)-based bulbs are used, energized with electric arcs or microwaves. Lower-power fluorescent lamps and LEDs can be used for static applications. Small high-pressure lamps can have light focused and transmitted to the work area via liquid-filled or fiber-optic light guides.
The impact of UV on polymers is used for modification of the (roughness and hydrophobicity) of polymer surfaces. For example, a poly(methyl methacrylate) surface can be smoothed by vacuum ultraviolet.
UV radiation is useful in preparing low-surface-energy polymers for adhesives. Polymers exposed to UV will oxidize, thus raising the surface energy of the polymer. Once the surface energy of the polymer has been raised, the bond between the adhesive and the polymer is stronger. | 0 | Theoretical and Fundamental Chemistry |
The increasing amount of genomic and molecular information is the basis for understanding higher-order biological systems, such as the cell and the organism, and their interactions with the environment, as well as for medical, industrial and other practical applications. The KEGG resource provides a reference knowledge base for linking genomes to biological systems, categorized as building blocks in the genomic space (KEGG GENES), the chemical space (KEGG LIGAND), wiring diagrams of interaction networks and reaction networks (KEGG PATHWAY), and ontologies for pathway reconstruction (BRITE database).
The KEGG PATHWAY database is a collection of manually drawn pathway maps for metabolism, genetic information processing, environmental information processing such as signal transduction, ligand–receptor interaction and cell communication, various other cellular processes and human diseases, all based on extensive survey of published literature. | 0 | Theoretical and Fundamental Chemistry |
Grazing-incidence small-angle scattering (GISAS) is a scattering technique used to study nanostructured surfaces and thin films. The scattered probe is either photons (grazing-incidence small-angle X-ray scattering, GISAXS) or neutrons (grazing-incidence small-angle neutron scattering, GISANS). GISAS combines the accessible length scales of small-angle scattering (SAS: SAXS or SANS) and the surface sensitivity of grazing incidence diffraction (GID). | 0 | Theoretical and Fundamental Chemistry |
T. rotula has been known to produce many types of polyunsaturated aldehydes, including (2E,4E/Z)-hepta-2,4-dienal, (2E,4E/Z,7Z)-deca-2,4,7-trienal, (2E,4E/Z)-octa-2,4-dienal, and (2E,4E/Z,7Z)-octa-2,4,7-trienal. These particular aldehydes are also produced by Stephanopyxis turris and Skeletonema costatum in response to wounding. Phaeocystis pouchetii and Skeletonema marinoi also produce various octadienal and heptadienal isomers. | 1 | Applied and Interdisciplinary Chemistry |
Tsumaki described the first metal–salen complexes in 1938. He found that the cobalt(II) complex Co(salen) reversibly binds O, which led to intensive research on cobalt complexes of salen and related ligands for their capacity for oxygen storage and transport, looking for potential synthetic oxygen carriers. Cobalt salen complexes also replicate certain aspects of vitamin B. | 0 | Theoretical and Fundamental Chemistry |
Shanon Shah is also a playwright. His play Air Con was by the Instant Cafe Theatre Company's FIRSTWoRKS programme. The play, directed by Jo Kukathas and Zalfian Fuzi, was performed to critical acclaim prompting a revival in 2009.
One reviewer praised not only the play's take on issues such as hate crimes against transsexuals, homophobic bullying in schools, racism and religious fundamentalism, but also its comedic touches and bilingual dialogue. Shanon has said he is greatly influenced by award-winning Malaysian actor and playwright Jit Murad.
Air Con was nominated in nine categories for the 7th BOH Cameronian Arts Awards, winning four awards, including Best Original Script (Bahasa Malaysia).
Shanon also co-wrote the screenplay and four original songs for Chris Chong Chan Fuis first full-length feature film Karaoke, which in 2009 was selected for the Directors Fortnight of the Cannes Film Festival. The songs for Karaoke eventually made it into Suara Yang Ku Dengar. | 1 | Applied and Interdisciplinary Chemistry |
The simplest mathematical model to explain the Vroman Effect is the Langmuir model using the Langmuir isotherm. More complex models include the Fruendlich isotherm and other modifications to the Langmuir model. This model explains the kinetics between reversible adsorption and desorption, assuming the adsorbate behaves as an ideal gas at isothermal conditions. | 0 | Theoretical and Fundamental Chemistry |
His father was a military physician. He was a student of Academician . In 1940, he defended his Candidate's Dissertation at the N.D. Zelinsky Institute of Organic Chemistry. In 1949, he defended his doctoral dissertation. From 1950 to 1992, Perekalin headed the Department of Organic Chemistry at the Herzen University. In this University he organized the Faculty of Chemistry. He taught in the Herzen University for 48 years. In 1995, he was appointed Soros Professor.
He has a son Pyotr.
Perekalin is the author of more than 350 scientific papers. | 0 | Theoretical and Fundamental Chemistry |
* Affecting blood pressure/(antihypertensive drugs): ACE inhibitors, angiotensin receptor blockers, beta-blockers, α blockers, calcium channel blockers, thiazide diuretics, loop diuretics, aldosterone inhibitors.
* Coagulation: anticoagulants, heparin, antiplatelet drugs, fibrinolytics, anti-hemophilic factors, haemostatic drugs.
* General: β-receptor blockers ("beta blockers"), calcium channel blockers, diuretics, cardiac glycosides, antiarrhythmics, nitrate, antianginals, vasoconstrictors, vasodilators.
* HMG-CoA reductase inhibitors (statins) for lowering LDL cholesterol inhibitors: hypolipidaemic agents. | 1 | Applied and Interdisciplinary Chemistry |
The adverse effects of lithium include:
;Very Common (> 10% incidence) adverse effects
* Confusion
* Constipation (usually transient, but can persist in some)
* Decreased memory
* Diarrhea (usually transient, but can persist in some)
* Dry mouth
* EKG changes — usually benign changes in T waves
* Hand tremor (usually transient, but can persist in some) with an incidence of 27%. If severe, psychiatrist may lower lithium dosage, change lithium salt type or modify lithium preparation from long to short acting (despite lacking evidence for these procedures) or use pharmacological help
* Headache
* Hyperreflexia — overresponsive reflexes
* Leukocytosis — elevated white blood cell count
* Muscle weakness (usually transient, but can persist in some)
* Myoclonus — muscle twitching
* Nausea (usually transient)
* Polydipsia — increased thirst
* Polyuria — increased urination
* Renal (kidney) toxicity which may lead to chronic kidney failure
* Vomiting (usually transient, but can persist in some)
* Vertigo
* Weight gain
;Common (1–10%) adverse effects
* Acne
* Extrapyramidal side effects — movement-related problems such as muscle rigidity, parkinsonism, dystonia, etc.
* Euthyroid goitre — i.e. the formation of a goitre despite normal thyroid functioning
* Hypothyroidism — a deficiency of thyroid hormone.
* Hair loss/hair thinning
;Unknown incidence
* Sexual dysfunction
* Hypoglycemia
* Glycosuria
Lithium carbonate can induce a 1–2 kg of weight gain.
In addition to tremors, lithium treatment appears to be a risk factor for development of parkinsonism-like symptoms, although the causal mechanism remains unknown.
Most side effects of lithium are dose-dependent. The lowest effective dose is used to limit the risk of side effects. | 1 | Applied and Interdisciplinary Chemistry |
Pure copper. Unlike other metals, copper is frequently used in its pure (99.9% Cu) unalloyed form for sheet and strip applications in roofing, exterior cladding, and flashing.
Tempering is a heat treatment technique used to increase the toughness of metals. Tempers determine the ductility of the metal, and therefore how well it forms and will hold its shape without additional support. In the U.S., copper is available in six tempers: 060 soft, hard cold rolled, cold rolled high yield, half hard, three quarter hard, and hard. In the U.K., only three designations exist: soft, half-hard, and hard. Copper and its alloys are defined in the U.S. in Standard Designations for Copper and Copper Alloys by ASTM; in Europe by BS EN 1172: 1997 - Copper and Copper Alloys in Europe; and in the U.K. by the British Standard Code of Practice CP143: Part12: 1970.
Cold rolled copper temper is by far the most popular in building construction in the U.S. It is less malleable than soft copper but is far stronger. Cold rolled hard tempered copper is often recommended for roofing and flashing installations. Roof sheets with higher tempers may be specified for certain applications.
Soft tempered copper is extremely malleable and offers far less resistance than cold rolled copper to the stresses induced by expansion and contraction. It is used for intricate ornamental work and where extreme forming is required, such as in complicated thru-wall flashing conditions.
The major use for high-yield copper is in flashing products, where malleability and strength are both important.
The thickness of sheet and strip copper is measured in the U.S. by its weight in ounces per square foot. Thicknesses commonly used in construction in the U.S. are between and . Since the industry often uses gauge numbers or actual thicknesses for sheet metal or other building materials, it is necessary to convert between the different measurement systems.
In Europe, phosphorus de-oxidized non-arsenical copper is used with the designation C106. The copper is rolled to thicknesses ranging between ( for curtain walling) but a thickness is usually used for roofing.
Alloyed copper. Copper alloys, such as brass and bronze, are also used in residential and commercial building structures. Variations in color stem primarily from differences in the alloy chemical composition.
Some of the more popular copper alloys and their associated Unified Numbering System (UNS) numbers developed by ASTM and SAE are as follows:
In practice, the term bronze may be used for a variety of copper alloys with little or no tin if they resemble true bronzes in color.
Further information on architectural copper alloys is available. | 1 | Applied and Interdisciplinary Chemistry |
The compressor has to run with the same speed (or fixed gear ratio) as its driving turbine and have equal power and pass the same flow as its driving turbine. This constitutes a gas generator which produces gas power. The compressor also has to pass the same flow as whatever uses the gas power, ie additional turbine stages for a single shaft engine or separate power turbines or a jet nozzle. This equal-flow requirement is alongside an equal pressure-ratio requirement, between overall compression and expansion ratios, and together they position the running line for steady state operation.
Single-shaft engines which drive an electric generator or helicopter rotor/aircraft propeller run with the compressor at no-load while accelerating to operating speed. No-load refers to a minimum fuelling as necessary to run the generator with no electrical load or rotor/propeller pitch at a minimum and occurs close to choke. Cohen et al. show electrical generators run up to required speed at no load. An increase in electrical load is obtained by increasing fuel flow. Barkey et al. give a detailed description of the sequence of events which bring the generator turbine to design speed, or grid frequency, with no load before increasing fuel as the load comes on. Grandcoing shows the Turbomeca Artouste helicopter engine constant speed operation from no-load idle to maximum power. No-load is minimum rotor pitch and idle fuel flow. The increase in fuel flow is shown on a compressor map as lines of constant engine temperature ratio, Turbine inlet temperature/Compressor inlet temperature. Grandcoing also shows the effect of a rapid load increase where the speed droops before regaining its required setting. | 0 | Theoretical and Fundamental Chemistry |
A natural nuclear fission reactor is a uranium deposit where self-sustaining nuclear chain reactions occur. The conditions under which a natural nuclear reactor could exist were predicted in 1956 by Paul Kuroda. The remnants of an extinct or fossil nuclear fission reactor, where self-sustaining nuclear reactions have occurred in the past, are verified by analysis of isotope ratios of uranium and of the fission products (and the stable daughter nuclides of those fission products). This was first discovered in 1972 in Oklo, Gabon by researchers from French Commissariat à lénergie atomique (CEA) under conditions very similar to Kurodas predictions.
Oklo is the only location where this phenomenon is known to have occurred, and consists of 16 sites with patches of centimeter-sized ore layers. There, self-sustaining nuclear fission reactions are thought to have taken place approximately 1.7 billion years ago, during the Statherian period of the Paleoproterozoic, and continued for a few hundred thousand years, probably averaging less than 100 kW of thermal power during that time.
Gabon was a French colony when the first analyses of the subsoil were carried out by the CEA from the MABA base in Franceville, more precisely by its industrial direction which later became COGEMA, leading in 1956 to the discovery of uranium deposits in the region.
France almost immediately opened mines, managed by the “Compagnie des Mines dUranium de Franceville” (COMUF), to exploit the resources, near the village of Mounana. After independence in 1960, the state of Gabon received a small share of the companys profits.
The "Oklo phenomenon" was discovered in June 1972 by the laboratory at the uranium enrichment plant in Pierrelatte, France. Routine analysis of a sample of natural uranium revealed a slight but abnormal deficit of uranium 235 (U). The normal proportion of U is 0.7202%, whereas this sample showed only 0.7171%. As the quantities of fissile isotopes are precisely catalogued, this discrepancy had to be explained, so an investigation was launched by CEA on samples from all the mines operated by CEA in France, Gabon and Niger, and at all stages of ore processing and uranium purification.
For uranium and U analyses, CEAs Production Division relies on the Analytical Laboratory at the Pierrelatte plant and on CEAs Central Analysis and Control Laboratory at Cadarache, headed by Michele Neuilly, where Jean François Dozol is in charge of mass spectrometry analyses. | 0 | Theoretical and Fundamental Chemistry |
In addition to the nature of the detected signal, other implementations in this platform allows for an even higher signal-to-noise ratio. In the case of magnetic sequencing by hybridization, a set of overlapping tiles is used such that the sequence of each nucleotide is determined by the hybridization of an 8-mer. Therefore, the instrument only requires the sensitivity to detect a change of ~ 6 nm (the length of 8 nucleotides). Similarly, for sequencing by ligation cycles, successful incorporation is characterized by a ~5 nm increase (ligation of a 7-mer) followed by a ~ 4 nm decrease (RNase cleavage of 6-mer) in hairpin length. In this case, the decrease in length in the second step provides additional confirmation for the obtained signal. | 1 | Applied and Interdisciplinary Chemistry |
Stable isotope labeling involves the use of non-radioactive isotopes that can act as a tracers used to model several chemical and biochemical systems. The chosen isotope can act as a label on that compound that can be identified through nuclear magnetic resonance (NMR) and mass spectrometry (MS). Some of the most common stable isotopes are H, C, and N, which can further be produced into NMR solvents, amino acids, nucleic acids, lipids, common metabolites and cell growth media. The compounds produced using stable isotopes are either specified by the percentage of labeled isotopes (i.e. 30% uniformly labeled C glucose contains a mixture that is 30% labeled with carbon isotope and 70% naturally labeled carbon) or by the specifically labeled carbon positions on the compound (i.e. 1-C glucose which is labeled at the first carbon position of glucose).
A network of reactions adopted from the glycolysis pathway and the pentose phosphate pathway is shown in which the labeled carbon isotope rearranges to different carbon positions throughout the network of reactions. The network starts with fructose 6-phosphate (F6P), which has 6 carbon atoms with a label C at carbon position 1 and 2. 1,2-C F6P becomes two glyceraldehyde 3-phosphate (G3P), one 2,3-C T3P and one unlabeled T3P. The 2,3-C T3P can now be reacted with sedoheptulose 7-phosphate (S7P) to form an unlabeled erythrose 4-phosphate(E4P) and a 5,6-C F6P. The unlabeled T3P will react with the S7P to synthesize unlabeled products. The figure demonstrates the use of stable isotope labeling to discover the carbon atom rearrangement through reactions using position specific labeled compounds. | 0 | Theoretical and Fundamental Chemistry |
In biochemistry, an ultratrace element is a chemical element that normally comprises less than one microgram per gram of a given organism (i.e. less than 0.0001% by weight), but which plays a significant role in its metabolism.
Possible ultratrace elements in humans include boron, silicon, nickel, vanadium and cobalt. Other possible ultratrace elements in other organisms include bromine, cadmium, fluorine, lead, lithium, and tin. | 1 | Applied and Interdisciplinary Chemistry |
Gene therapy uses genetically modified viruses to deliver genes which can cure disease in humans. Although gene therapy is still relatively new, it has had some successes. It has been used to treat genetic disorders such as severe combined immunodeficiency, and Lebers congenital amaurosis. Treatments are also being developed for a range of other currently incurable diseases, such as cystic fibrosis, sickle cell anemia, Parkinsons disease, cancer, diabetes, heart disease and muscular dystrophy. These treatments only effect somatic cells, meaning any changes would not be inheritable. Germline gene therapy results in any change being inheritable, which has raised concerns within the scientific community.
In 2015, CRISPR was used to edit the DNA of non-viable human embryos. In November 2018, He Jiankui announced that he had edited the genomes of two human embryos, in an attempt to disable the CCR5 gene, which codes for a receptor that HIV uses to enter cells. He said that twin girls, Lulu and Nana, had been born a few weeks earlier and that they carried functional copies of CCR5 along with disabled CCR5 (mosaicism) and were still vulnerable to HIV. The work was widely condemned as unethical, dangerous, and premature. | 1 | Applied and Interdisciplinary Chemistry |
The molecular structures of nontrigonal pnictogen compounds reveal the steric strain in these molecules, and significantly differing bond angles at the pnictogen atoms indicate a considerable distortion of the coordination spheres.
In particular, the geometry at the central part of these compounds deviate strongly from traditional pnictogen compounds, and indicate molecular strain with an approach to a T-type molecular configuration. With different ligand motifs, the bond angles at pnictogen atoms can vary from 100˚ to almost 180˚. The flattened geometry of these molecules influences the relatively low energetic barriers for inversion of the configuration via planar coordinated pnictogen atoms in the transition state. These low barriers are in accordance with the dynamic behavior and fast equilibration processes observed in ambient temperature NMR.
Results of quantum chemical calculations confirm that in these compounds, the lone pair of electrons at the pnictogen atoms is localized in orbitals with relatively high s-character. From these results, only weak nucleophilicity was derived in accordance with some experimental observations such as the inertness towards benzyl bromide. The LUMO is delocalized but has important contributions from pnictogen empty p orbitals, which should favor a nucleophilic attack of substrates at this position in accordance with experimental findings. The pnictogen atom forms a three-center-four-electron bond with the two flanking nitrogen atoms, which is manifested by the HOMO-2.
For nontrigonal bismuth compounds, a Bi(I) electronic structure could be shown to be most appropriate. Natural bond orbital (NBO) analysis reveals an s-type lone pair and a p-type lone pair at the metal, with the remaining two p orbitals being involved in one two-center-two-electron bond and one three-center-two-electron bond. The p-type lone pair NBO has less than 2 electron occupancy as it is delocalized over the ligand frame. Although considerable Bi(I) character is indicated for the Bi compound, it exhibits reactivity similar to Bi(III) electrophiles, and expresses either a vacant or a filled p orbital at Bi.
From these results, two types of resonance structures can be drawn, one with a filled s-orbital and a vacant p orbital at the pnictogen center, the other one with negative charge on pnictogen, arising from the redox-non-innocent nature of the ligand. This is evident by shorter C-N bond lengths in nontrigonal pnictogen compounds than C-N single bonds in the corresponding ligands. These structures may reflect the specific bonding situation in these strained molecular systems. | 0 | Theoretical and Fundamental Chemistry |
A different perspective on Alzheimers is revealed by a mouse study that has found that APP possesses ferroxidase activity similar to ceruloplasmin, facilitating iron export through interaction with ferroportin; it seems that this activity is blocked by zinc trapped by accumulated Aβ in Alzheimers. It has been shown that a single nucleotide polymorphism in the 5'UTR of APP mRNA can disrupt its translation.
The hypothesis that APP has ferroxidase activity in its E2 domain and facilitates export of Fe(II) is possibly incorrect since the proposed ferroxidase site of APP located in the E2 domain does not have ferroxidase activity.
As APP does not possess ferroxidase activity within its E2 domain, the mechanism of APP-modulated iron efflux from ferroportin has come under scrutiny. One model suggests that APP acts to stabilize the iron efflux protein ferroportin in the plasma membrane of cells thereby increasing the total number of ferroportin molecules at the membrane. These iron-transporters can then be activated by known mammalian ferroxidases (i.e. ceruloplasmin or hephaestin). | 1 | Applied and Interdisciplinary Chemistry |
Eigencolloid is a term derived from the German language (eigen: own) and used to designate colloids made of pure phases. Also known as intrinsic colloids.
Eigencolloids are metal oxyhydroxide colloids on the nanometer scale formed by aggregation of hydrolyzed metal ions. They are characterized by a very large specific surface area (up to 2000 m/g) and a high reactivity. They hold promise for the development of new industrial catalysts.
Many such colloids are formed by the hydrolysis of heavy metals cations or radionuclides, such as, for example, Tc(OH), Th(OH), U(OH), Pu(OH), or Am(OH).
The term eigencolloid or intrinsic colloid, is often used in distinction to a pseudocolloid. A pseudocolloid is one in which elements (colloids or cations) become adsorbed onto pre-existing groundwater colloids due to their affinity to these colloids or to the hydrophobic properties of the dispersing medium.
In environmental chemistry, enhanced migration of heavy metal and radioactive metal contaminants in ground and surface waters is often facilitated by eigencolloid formation. | 0 | Theoretical and Fundamental Chemistry |
The F fraction derives its name from the term "Fraction 1" and F (written as a subscript letter "o", not "zero") derives its name from being the binding fraction for oligomycin, a type of naturally derived antibiotic that is able to inhibit the F unit of ATP synthase. These functional regions consist of different protein subunits — refer to tables. This enzyme is used in synthesis of ATP through aerobic respiration. | 0 | Theoretical and Fundamental Chemistry |
A rotating impeller containing two or more vanes divides the spaces between the vanes into discrete volumes and each rotation (or vane passing) is counted.
: Flow = volume of measuring chamber × RPM × 4 | 1 | Applied and Interdisciplinary Chemistry |
Monoclonal antibodies used for autoimmune diseases include infliximab and adalimumab, which are effective in rheumatoid arthritis, Crohn's disease, ulcerative colitis and ankylosing spondylitis by their ability to bind to and inhibit TNF-α. Basiliximab and daclizumab inhibit IL-2 on activated T cells and thereby help prevent acute rejection of kidney transplants. Omalizumab inhibits human immunoglobulin E (IgE) and is useful in treating moderate-to-severe allergic asthma. | 1 | Applied and Interdisciplinary Chemistry |
In the ocean, alkalinity is completely dominated by carbonate and bicarbonate plus a small contribution from borate.
Thus the chemical equation for alkalinity in seawater is:
: A = [HCO] + 2[CO] + [B(OH)]
There are many methods of alkalinity generation in the ocean. Perhaps the most well known is the dissolution of calcium carbonate to form Ca and (carbonate). The carbonate ion has the potential to absorb two hydrogen ions. Therefore, it causes a net increase in ocean alkalinity. Calcium carbonate dissolution occurs in regions of the ocean which are undersaturated with respect to calcium carbonate.
The increasing carbon dioxide level in the atmosphere, due to carbon dioxide emissions, results in increasing absorption of CO from the atmosphere into the oceans. This does not affect the ocean's alkalinity but it does result in a reduction in pH value (called ocean acidification). Ocean alkalinity enhancement has been proposed as one option to add alkalinity to the ocean and therefore buffer against pH changes.
Biological processes have a much greater impact on oceanic alkalinity on short (minutes to centuries) timescales. Aerobic respiration of organic matter can decrease alkalinity by releasing protons. Denitrification and sulfate reduction occur in oxygen-limited environments. Both of these processes consume hydrogen ions (thus increasing alkalinity) and release gases (N or HS), which eventually escape into the atmosphere. Nitrification and sulfide oxidation both decrease alkalinity by releasing protons as a byproduct of oxidation reactions. | 0 | Theoretical and Fundamental Chemistry |
The simplest case refers to the formation of a strictly linear polymer by the reaction (usually by condensation) of two monomers in equimolar quantities. An example is the synthesis of nylon-6,6 whose formula is
from one mole of hexamethylenediamine, , and one mole of adipic acid, . For this case
In this equation
* is the number-average value of the degree of polymerization, equal to the average number of monomer units in a polymer molecule. For the example of nylon-6,6 ( diamine units and diacid units).
* is the extent of reaction (or conversion to polymer), defined by
** is the number of molecules present initially as monomer
** is the number of molecules present after time . The total includes all degrees of polymerization: monomers, oligomers and polymers.
This equation shows that a high monomer conversion is required to achieve a high degree of polymerization. For example, a monomer conversion, , of 98% is required for = 50, and = 99% is required for = 100. | 0 | Theoretical and Fundamental Chemistry |
Aristid von Grosse (January 1905 – July 21, 1985) was a German nuclear chemist. During his work with Otto Hahn, he got access to waste material from radium production, and with this starting material he was able in 1927 to isolate protactinium(V) oxide and was later able to produce metallic protactinium by decomposition of protactinium(V) iodide.
From 1948 to 1969, he was president of the Research Institute of Temple University and was later affiliated with the laboratories of the Franklin Institute in Philadelphia until his retirement in 1979. In 1971, he received a United States Atomic Energy Commission award in recognition of his "outstanding contributions to the development of nuclear energy."
Aristid was born in Riga in January 1905 and moved to the United States in 1930. He retired in 1979 and died of pneumonia in Laguna Hills, California on July 21, 1985. | 0 | Theoretical and Fundamental Chemistry |
Griffin's method for non-ionic surfactants as described in 1954 works as follows:
where is the molecular mass of the hydrophilic portion of the molecule, and M is the molecular mass of the whole molecule, giving a result on a scale of 0 to 20.
An HLB value of 0 corresponds to a completely lipophilic/hydrophobic molecule, and a value of 20 corresponds to a completely hydrophilic/lipophobic molecule.
The HLB value can be used to predict the surfactant properties of a molecule:
* < 10 : Lipid-soluble (water-insoluble)
* > 10 : Water-soluble (lipid-insoluble)
* 1 to 3: anti-foaming agent
* 3 to 6: W/O (water in oil) emulsifier
* 7 to 9: wetting and spreading agent
* 13 to 16: detergent
* 8 to 16: O/W (oil in water) emulsifier
* 16 to 18: solubiliser or hydrotrope | 0 | Theoretical and Fundamental Chemistry |
The 4n chain of thorium-232 is commonly called the "thorium series" or "thorium cascade". Beginning with naturally occurring thorium-232, this series includes the following elements: actinium, bismuth, lead, polonium, radium, radon and thallium. All are present, at least transiently, in any natural thorium-containing sample, whether metal, compound, or mineral. The series terminates with lead-208.
Plutonium-244 (which appears several steps above thorium-232 in this chain if one extends it to the transuranics) was present in the early Solar System, and is just long-lived enough that it should still survive in trace quantities today, though it is uncertain if it has been detected.
The total energy released from thorium-232 to lead-208, including the energy lost to neutrinos, is 42.6 MeV. | 0 | Theoretical and Fundamental Chemistry |
The earliest reported drug checking activity began in Amsterdam in November 1970 with a group from the University Hospital of Amsterdam and samples obtained through psychiatrists working with people who used drugs.
The earliest reported drug checking service is the Drug Information and Monitoring System (DIMS) in the Netherlands supported by the Ministry of Health, Welfare and Sport. Since 1992 the service has tested over 100,000 drug samples at a national network of twenty-three testing facilities. Service users receive results within a week via phone or email and the service publishes aggregated results describing what substances are in use.
European countries have led the introduction of drug checking services, with Asociación Hegoak Elkartea founded in Spain in 1994, TechnoPlus in France founded in 1995, and Modus Fiesta in Belgium in 1996. DanceSafe have operated in the USA since 1998 providing reagent testing and harm reduction advice.
More recent services include Neutravel founded in Italy in 2007, The Loop founded in the UK in 2013 and KnowYourStuffNZ in New Zealand in 2015 with Pill Testing Australia launching after a successful trial in 2018.
In 2008, the Trans-European Drug Information network (TEDI) was created, a database compiling information from different non-profit drug checking services located in different European countries.
On March 31, 2017, a coalition of drug safety organisations hosted the first-ever International Drug Checking Day to raise awareness of safer drug use. The initiative was aimed at recreational users, with a particular emphasis on the nightlife community, and aims to promote harm reduction—accepting that people will choose to take drugs, and providing them with tools to minimise the risks.
In November 2021 New Zealand became the first country to make drug checking fully legal after previously allowing this under temporary legislation. Other countries like the Netherlands allow drug checking but do not have legislation to protect the clients or testers, and the practice exists in a legal grey area in countries like the US and UK. | 0 | Theoretical and Fundamental Chemistry |
Davyum was the proposed name for a chemical element found by chemist Serge Kern in 1877. It was shown that the material was a mixture of iridium and rhodium. In 1950 it was proposed that the new metal might also have contained rhenium, which had not been discovered in Kern's time. | 1 | Applied and Interdisciplinary Chemistry |
Astrophysical fluid dynamics is a branch of modern astronomy which deals with the motion of fluids in outer space using fluid mechanics, such as those that make up the Sun and other stars. The subject covers the fundamentals of fluid mechanics using various equations, such as continuity equations, the Navier–Stokes equations, and Euler's equations of collisional fluids. Some of the applications of astrophysical fluid dynamics include dynamics of stellar systems, accretion disks, astrophysical jets, Newtonian fluids, and the fluid dynamics of galaxies. | 1 | Applied and Interdisciplinary Chemistry |
Gunnar Aksnes (8 August 1926 in Kvam, Hardanger – 31 January 2010 in Bergen, Hordaland) was a Norwegian chemist and poet, the brother of the astronomer Kaare Aksnes, married to Milly Aksnes (b. 1928) | 0 | Theoretical and Fundamental Chemistry |
Enzymes and enzymatic complexes able to break down difficult-to-transform macromolecules such as cellulose, hemicelluloses, pectin and proteins. Solid state fermentation is well suited for the production of various enzymatic complexes composed of multiple enzymes. Enzymatic compounds generated by SSF find outlets in all sectors where digestibility, solubility or viscosity is needed.
This is why SSF enzymes are widely used in the following industries:
* fruit and vegetable transformation (pectinases)
* baking (hemicellulases)
* animal feeding (hemicellulases and cellulases)
* bio ethanol (cellulases and hemicellulases)
* brewing and distilling (hemicellulases) | 1 | Applied and Interdisciplinary Chemistry |
At pressures above approximately 10-13 GPa and temperatures up to around 700 K, α-iron changes into a hexagonal close-packed (hcp) structure, which is also known as ε-iron or hexaferrum; the higher-temperature γ-phase also changes into ε-iron, but generally requires far higher pressures as temperature increases. The triple point of hexaferrum, ferrite, and austenite is 10.5 GPa at 750 K. Antiferromagnetism in alloys of epsilon-Fe with Mn, Os and Ru has been observed. | 1 | Applied and Interdisciplinary Chemistry |
Podocin is localized on the membranes of podocyte pedicels (foot-like long processes), where it oligomerizes in lipid rafts together with nephrin to form the filtration slits. | 1 | Applied and Interdisciplinary Chemistry |
Subsets and Splits
No community queries yet
The top public SQL queries from the community will appear here once available.