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Cadmium telluride is the only thin film material so far to rival crystalline silicon in cost/watt. However cadmium is highly toxic and tellurium (anion: "telluride") supplies are limited. The cadmium present in the cells would be toxic if released. However, release is impossible during normal operation of the cells and is unlikely during fires in residential roofs. A square meter of CdTe contains approximately the same amount of Cd as a single C cell nickel-cadmium battery, in a more stable and less soluble form. | 0 | Theoretical and Fundamental Chemistry |
In prokaryotes, structural genes of related function are typically adjacent to one another on a single strand of DNA, forming an operon. This permits simpler regulation of gene expression, as a single regulatory factor can affect transcription of all associated genes. This is best illustrated by the well-studied lac operon, in which three structural genes (lacZ, lacY, and lacA) are all regulated by a single promoter and a single operator. Prokaryotic structural genes are transcribed into a polycistronic mRNA and subsequently translated.
In eukaryotes, structural genes are not sequentially placed. Each gene is instead composed of coding exons and interspersed non-coding introns. Regulatory sequences are typically found in non-coding regions upstream and downstream from the gene. Structural gene mRNAs must be spliced prior to translation to remove intronic sequences. This in turn lends itself to the eukaryotic phenomenon of alternative splicing, in which a single mRNA from a single structural gene can produce several different proteins based on which exons are included. Despite the complexity of this process, it is estimated that up to 94% of human genes are spliced in some way. Furthermore, different splicing patterns occur in different tissue types.
An exception to this layout in eukaryotes are genes for histone proteins, which lack introns entirely. Also distinct are the rDNA clusters of structural genes, in which 28S, 5.8S, and 18S sequences are adjacent, separated by short internally transcribed spacers, and likewise the 45S rDNA occurs five distinct places on the genome, but is clustered into adjacent repeats. In eubacteria these genes are organized into operons. However, in archaebacteria these genes are non-adjacent and exhibit no linkage. | 1 | Applied and Interdisciplinary Chemistry |
Joule effect and Joule's law are any of several different physical effects discovered or characterized by English physicist James Prescott Joule. These physical effects are not the same, but all are frequently or occasionally referred to in the literature as the "Joule effect" or "Joule law" These physical effects include:
* "Joule's first law" (Joule heating), a physical law expressing the relationship between the heat generated and the current flowing through a conductor.
* Joule's second law states that the internal energy of an ideal gas is independent of its volume and pressure, depending only on its temperature.
* Magnetostriction, a property of ferromagnetic materials that causes them to change their shape when subjected to a magnetic field.
* The Joule effect (during Joule expansion), the temperature change of a gas (usually cooling) when it is allowed to expand freely.
* The Joule–Thomson effect, the temperature change of a gas when it is forced through a valve or porous plug while keeping it insulated so that no heat is exchanged with the environment.
* The Gough–Joule effect or the Gow–Joule effect, which is the tendency of elastomers to contract if heated while they are under tension. | 0 | Theoretical and Fundamental Chemistry |
To make equations of the previous section applicable to the states belonging to the continuum spectrum, they should be rewritten in terms of matrix elements of the momentum . In absence of magnetic field, the Hamiltonian can be written as , and calculating a commutator in the basis of eigenfunctions of results in the relation between matrix elements
Next, calculating matrix elements of a commutator in the same basis and eliminating matrix elements of , we arrive at
Because , the above expression results in a sum rule
where are oscillator strengths for quantum transitions between the states and . This is the Thomas-Reiche-Kuhn sum rule, and the term with has been omitted because in confined systems such as atoms or molecules the diagonal matrix element due to the time inversion symmetry of the Hamiltonian . Excluding this term eliminates divergency because of the vanishing denominator. | 0 | Theoretical and Fundamental Chemistry |
The radial spoke is known to play a role in the mechanical movement of the flagellum/cilium. For example, mutant organisms lacking properly functioning radial spokes have flagella and cilia that are immotile. Radial spokes also influence the cilium "waveform"; that is, the exact bending pattern the cilium repeats.
How the radial spoke carries out this function is poorly understood. Radial spokes are believed to interact with both the central pair microtubules and the dynein arms, perhaps in a way that maintains the rhythmic activation of the dynein motors. For example, one of the radial spoke subunits, RSP3, is an anchor protein predicted to hold another protein called protein kinase A (PKA). PKA would theoretically then be able to activate/inactivate the adjacent dynein arms via its kinase activity. | 1 | Applied and Interdisciplinary Chemistry |
Ziryabs career flourished in Al-Andalus. According to the Encyclopaedia of Islam, he was born around 175 AH/790 into a family of mawali' of the caliph al-Mahdi. His ethnic origin is unclear. Based on his appearance and background, different sources suggest him to be a Persian, Kurdish, Arab, Sindi or African. According to Ibn Hayyan, ‘Ali Ibn Nafi’ was called Blackbird because of his extremely dark complexion, the clarity of his voice and “the sweetness of his character.”
As the Islamic armies conquered more and more territories, their musical culture spread with them, as far as western China in the east and Iberia in the west. After their 8th-century conquest of nearly all of Hispania, which they renamed Al-Andalus, the Muslims were a small minority for quite some time, greatly outnumbered by the majority Christians and a smaller community of Jews, who had their own styles of music. With their arrival, the Muslims and Arabs introduced new styles of music, and the main cities of Iberia soon became well-known centers for music within the Islamic world. During the 8th and 9th centuries, many musicians and artists from across the Islamic world flocked to Iberia. While many were talented, Ziryab surpassed them all.
Ziryab was most likely born in Baghdad and was trained in the art of music from a young age. During that time, Baghdad was an important center of music in the Muslim world. The sources all agree that the accomplished and talented musician Ibrahim al-Mawsili was Ziryab's teacher. There is some debate about how he arrived in al-Andalus, but he may have offended his patron or some powerful figure with his musical talent.
One account recorded by al-Maqqari says that Ziryab inspired the jealousy of his mentor by giving an impressive performance for the caliph Harun al-Rashid (d. 809), with the result that al-Mawsili told him to leave the city. Earlier, more reliable sources indicate that he outlived both Harun and his son al-Amin and left after al-Amin's death in 813.
Ziryab left Baghdad during the reign of al-Mamun some time after the year 813. He then traveled first to Syria and then Ifriqiya (Tunisia) in Kairouan, where he lived at the Aghlabid court of Ziyadat Allah (ruled 816–837). Ziryab fell out with Ziyadat Allah but was invited to Al-Andalus by the Umayyad prince, Al-Hakam I (ruled 796–822). He found on arrival in 822 that the prince had died, but the princes son, Abd ar-Rahman II, renewed his fathers invitation. Ziryab settled in Córdoba with a monthly salary of 200 gold Dinars, and he soon became celebrated as the courts aficionado of food, fashion, singing, and music. He introduced standards of excellence in all these fields as well as setting new norms for elegant and noble manners. He was an intimate companion of the prince and established a school of music that trained singers and musicians and which influenced musical performance for at least two generations after him.
Al-Maqqari states in his Nafh al-Tib (Fragrant Breeze): "There never was, either before or after him (Ziryab), a man of his profession who was more generally beloved and admired". | 1 | Applied and Interdisciplinary Chemistry |
Materials supporting quantum spin liquid states may have applications in data storage and memory. In particular, it is possible to realize topological quantum computation by means of spin-liquid states. Developments in quantum spin liquids may also help in the understanding of high temperature superconductivity. | 0 | Theoretical and Fundamental Chemistry |
Fritz Strassmann had come to the Kaiser Wilhelm Institute for Chemistry to study under Hahn in order to improve his employment prospects. After the Nazi Party came to power in Germany in 1933, Strassmann declined a lucrative offer of employment because it required political training and Nazi Party membership. Later, rather than become a member of a Nazi-controlled organisation, Strassmann resigned from the Society of German Chemists when it became part of the Nazi German Labour Front. As a result, he could neither work in the chemical industry nor receive his habilitation, the prerequisite for an academic position. Meitner persuaded Hahn to hire Strassmann as an assistant. Soon he would be credited as a third collaborator on the papers they produced, and would sometimes even be listed first.
Hahn spent February to June 1933 in the United States and Canada as a visiting professor at Cornell University. He gave an interview to the Toronto Star Weekly in which he painted a flattering portrait of Adolf Hitler:
The April 1933 Law for the Restoration of the Professional Civil Service banned Jews and communists from academia. Meitner was exempt from its impact because she was an Austrian rather than a German citizen. Haber was likewise exempt as a veteran of World War I, but chose to resign his directorship of the Kaiser Wilhelm Institute of Physical Chemistry and Electrochemistry in protest on 30 April 1933, but the directors of the other Kaiser Wilhelm Institutes, even the Jewish ones, complied with the new law, which applied to the KWS as a whole and those Kaiser Wilhelm institutes with more than 50% state support, which exempted the KWI for Chemistry. Hahn therefore did not have to fire any of his own full-time staff, but as the interim director of Habers institute, he dismissed a quarter of its staff, including three department heads. Gerhart Jander was appointed the new director of Habers old institute, and, ironically, reoriented it towards chemical warfare research.
Like most KWS institute directors, Haber had accrued a large discretionary fund. It was his wish that it be distributed to the dismissed staff to facilitate their emigration, but the Rockefeller Foundation insisted that the funds either be used for scientific research or returned. Hahn brokered a deal whereby 10 per cent of the funds would be allocated to Haber's people. In August 1933 the administrators of the KWS were alerted that several boxes of Rockefeller Foundation-funded equipment was about to be shipped to Herbert Freundlich, one of the department heads that Hahn had dismissed, in England. Hahn complied with an order to halt the shipment, but when Planck, the president of the KWS since 1930, returned from vacation, he ordered Hahn to expedite the shipment.
Haber died on 29 January 1934. A memorial service was held on the first anniversary of his death. University professors were forbidden to attend, so they sent their wives in their place. Hahn, Planck and Joseph Koeth attended, and gave speeches. The aging Planck did not seek re-election, and was succeeded in 1937 as president by Carl Bosch, a Nobel Prize winner in Chemistry and the Chairman of the Board of IG Farben, a company which had bankrolled the Nazi Party since 1932. Ernst Telschow became Secretary of the KWS. Telschow was an enthusiastic supporter of the Nazis, but was also loyal to Hahn, being one of his former students, and Hahn welcomed his appointment. Hahns chief assistant, Otto Erbacher, became the KWI for Chemistrys party steward (Vertrauensmann). | 0 | Theoretical and Fundamental Chemistry |
ROP proteins are a type of monomeric G proteins found in plants belonging to the Rho family. ROP binding to GTP or GDP determines its activity due to conformational changes within its structure. Within the G-domain of the structure are the G-box motifs G1-5. These motifs are formed during protein folding and are composed of conserved sequences that are responsible for nucleotide and magnesium binding as well as hydrolysis of GTP. Motifs G2 (switch I loop) and G3 (switch II loop) possess distinct conformations depending on GTP binding state. In addition, the G-domain contains a unique and conserved helical domain commonly found in Rho family proteins called αi.
Specific locations within the 3D ROP protein structure, including the amino acids 13-20, 60-64, and 118-121, act as binding sites during protein activity. The serine residue at amino acid 74 has been shown to be a potential protein activity regulation site through phosphorylation. | 1 | Applied and Interdisciplinary Chemistry |
All matter can be thought of as matter waves, from small particles such as electrons up to macroscopic objects – although it is impossible to measure any of the "wave-like" behavior of macroscopic objects. Waves can move around objects and create interference patterns, and a classic example is the Young's two-slit experiment shown in Figure 2, where a wave impinges upon two slits in the first of the two images (blue waves). After going through the slits there are directions where the wave is stronger, ones where it is weaker – the wave has been diffracted. If instead of two slits there are a number of small points then similar phenomena can occur as shown in the second image where the wave (red and blue) is coming in from the bottom right corner. This is comparable to diffraction of an electron wave where the small dots would be atoms in a small crystal, see also note. Note the strong dependence on the relative orientation of the crystal and the incoming wave.
Close to an aperture or atoms, often called the "sample", the electron wave would be described in terms of near field or Fresnel diffraction. This has relevance for imaging within electron microscopes, whereas electron diffraction patterns are measured far from the sample, which is described as far-field or Fraunhofer diffraction. A map of the directions of the electron waves leaving the sample will show high intensity (white) for favored directions, such as the three prominent ones in the Young's two-slit experiment of Figure 2, while the other directions will be low intensity (dark). Often there will be an array of spots (preferred directions) as in Figure 1 and the other figures shown later. | 0 | Theoretical and Fundamental Chemistry |
Flame photometry is a type of atomic absorption spectroscopy. It is also known as flame emission spectroscopy. A photoelectric flame photometer is an instrument used in inorganic chemical analysis to determine the concentration of certain metal ions, among them sodium, potassium, lithium, and calcium. Group 1 (alkali metals) and Group 2 (alkaline earth metals) are quite sensitive to flame photometry due to their low excitation energies.
In principle, it is a controlled flame test with the intensity of the flame color quantified by photoelectric circuitry. The intensity of the color will depend on the energy that had been absorbed by the atoms that was sufficient to vaporise them. The sample is introduced to the flame at a constant rate. Filters select which colours the photometer detects and exclude the influence of other ions. Before use, the device requires calibration with a series of standard solutions of the ion to be tested.
Flame photometry is crude but inexpensive compared to flame emission spectroscopy or ICP-AES, where the emitted light is analyzed with a monochromator. Its status is similar to that of the colorimeter (which uses filters) compared to the spectrophotometer (which uses a monochromator). It also has the range of metals that could be analysed and the limit of detection are also considered | 0 | Theoretical and Fundamental Chemistry |
The following outline is provided as an overview of and topical guide to chemical engineering:
Chemical engineering – deals with the application of physical science (e.g., chemistry and physics), and life sciences (e.g., biology, microbiology and biochemistry) with mathematics and economics, to the process of converting raw materials or chemicals into more useful or valuable forms. In addition to producing useful materials, modern chemical engineering is also concerned with pioneering valuable new materials and techniques – such as nanotechnology, fuel cells and biomedical engineering. | 1 | Applied and Interdisciplinary Chemistry |
Many free mesoionic carbenes are synthesized from their protonated salt form by deprotonation using strong potassium bases, such as potassium bis(trimethylsilyl)amide (KHMDS) or potassium tert-butoxide (KOt-Bu). Potassium bases are used because they do not form stable carbene-alkali metal adducts.
Imidazolin-4-ylidenes (MIC) would form rather than imidazolin-2-ylidenes (NHC) due to blocking the C2 position. The C2 carbenes are thermodynamically more stable than their C4 counterparts due to resonance and inductive carbon-nitrogen interactions. Also, calculations show that the C4 hydrogen is less acidic than the C2 hydrogen of imidazole. This data suggests that the C2 position should be activated preferentially to the C4 position unless the C2 position is blocked. Aryl and bulky alkyl groups (such as isopropyl) are good at blocking the C2 position from being activated. | 0 | Theoretical and Fundamental Chemistry |
Transforming growth factor beta-1-induced transcript 1 plays a role in a number of cell functions. Originally, TGFB1I1 was isolated as a senescence-inducing gene from mouse osteoblastic cells through treatment with transforming growth factor beta-1 and hydrogen peroxide. During this, TGFB1I1 was also being independently discovered by numerous other groups and was characterized as a focal adhesion protein, an androgen and glucocorticoid receptor co-activator, a negative regulator of muscle differentiation, and major player in the recovery of arterial media. | 1 | Applied and Interdisciplinary Chemistry |
Saponifiable lipids have relevant applications as a source of biofuel and can be extracted from various forms of biomass to produce biodiesel. | 1 | Applied and Interdisciplinary Chemistry |
A Brønsted-Lowry acids strength corresponds with its ability to release a hydrogen ion. One common measure of acid strength for concentrated, superacidic liquid media is the Hammett acidity function, H. Based on its ability to quantitatively protonate benzene, the chlorinated carborane acid was conservatively estimated to have an H value at or below −18, leading to the common assertion that carborane acids are at least a million times stronger than 100% sulfuric acid (H = −12). However, since the H value measures the protonating ability of a liquid medium, the crystalline and high-melting nature of these acids precludes direct measurement of this parameter. In terms of pK, a slightly different measure of acidity defined as the ability of a given solute to undergo ionization in a solvent, carborane acids are estimated to have pK values below −20, even without electron-withdrawing substituents on the boron atoms (e.g., is estimated to have a pK of −24), with the (yet unknown) fully fluorinated analog having a calculated pK of −46. The known acid with one fewer fluorine is expected to be only slightly weaker (pK' < −40).
In the gas phase, has a computed acidity of 216 kcal/mol, compared to an experimentally determined acidity of 241 kcal/mol (in reasonable agreement with the computed value of 230 kcal/mol) for . In contrast, HSbF (a simplified model for the proton donating species in fluoroantimonic acid) has a computed gas phase acidity of 255 kcal/mol, while the previous experimentally determined record holder was (CFSO)NH, a congener of bistriflimide, at 291 kcal/mol. Thus, is likely the most acidic substance so far synthesized in bulk, in terms of its gas phase acidity. In view of its unique reactivity, it is also a strong contender for being the most acidic substance in the condensed phase (see above). Some even more strongly acidic derivatives have been predicted, with gas phase acidities < 200 kcal/mol.
Carborane acids differ from classical superacids in being well-defined one component substances. In contrast, classical superacids are often mixtures of a Brønsted acid and Lewis acid (e.g. HF/SbF). Despite being the strongest acid, the boron-based carborane acids are described as being "gentle", cleanly protonating weakly basic substances without further side reactions. Whereas conventional superacids decompose fullerenes due to their strongly oxidizing Lewis acidic component, carborane acid has the ability to protonate fullerenes at room temperature to yield an isolable salt. Furthermore, the anion that forms as a result of proton transfer is nearly completely inert. This property is what makes the carborane acids the only substances that are comparable in acidity to the mixed superacids that can also be stored in a glass bottle, as various fluoride-donating species (which attack glass) are not present or generated. | 0 | Theoretical and Fundamental Chemistry |
Metal alkene complexes are intermediates in many or most transition metal catalyzed reactions of alkenes: polymerization., hydrogenation, hydroformylation, and many other reactions. | 0 | Theoretical and Fundamental Chemistry |
Amides undergo many chemical reactions, although they are less reactive than esters. Amides hydrolyse in hot alkali as well as in strong acidic conditions. Acidic conditions yield the carboxylic acid and the ammonium ion while basic hydrolysis yield the carboxylate ion and ammonia. The protonation of the initially generated amine under acidic conditions and the deprotonation of the initially generated carboxylic acid under basic conditions render these processes non-catalytic and irreversible. Amides are also versatile precursors to many other functional groups. Electrophiles react with the carbonyl oxygen. This step often precedes hydrolysis, which is catalyzed by both Brønsted acids and Lewis acids. Enzymes, e.g. peptidases and artificial catalysts, are known to accelerate the hydrolysis reactions. | 0 | Theoretical and Fundamental Chemistry |
Heating of the surfaces via passing current through a conductive transparent film has been shown to repel and remove contamination. It has been used in inkjet printers to reduced ink contamination on sensor windows. | 0 | Theoretical and Fundamental Chemistry |
* Sigurd Hofmann: On Beyond Uranium – Journey to the end of the Periodic Table. In: Science Spectra Book Series, Volume 2, V. Moses, Series Editor, (hardback), (paperback), Taylor and Francis, London and New York, 2002, 216 Seiten, [https://books.google.com/books?id=s-6r1ojU_vgC online]
* Sigurd Hofmann: Synthesis of superheavy elements by cold fusion. Radiochimica Acta Band 99, 2011, S. 405–428, [https://www.degruyter.com/view/journals/ract/99/7-8/article-p405.pdf online]
* Sigurd Hofmann and Gottfried Münzenberg: The discovery of the heaviest elements. In: Reviews of Modern Physics, Band 72, 200, S. 733–767, [http://rmp.aps.org/abstract/RMP/v72/i3/p733_1 online]
* Sigurd Hofmann: Proton radioactivity. In: Nuclear decay modes, D.N. Poenaru, Editor, , IOP Publishing Ltd, 1996, S. 143–203 | 1 | Applied and Interdisciplinary Chemistry |
Since the beginning of scientific glass research in the 19th century thousands of glass property-composition datasets were published. The first attempt to summarize all those data systematically was the monograph "Glastechnische Tabellen". World War II and the Cold War prevented similar efforts for many years afterwards.
In 1956, "Phase Diagrams for Ceramists" was published the first time, containing a collection of phase diagrams. This database is known today as "Phase Equilibria Diagrams".
In 1991, the Japanese database Interglad was created, followed by the publication of the "Handbook of Glass Data" in 1983. The "Handbook of Glass Data" was later digitalized and substantially expanded under the name SciGlass. Currently, SciGlass contains properties of about 400,000 glass compositions, INTERGLAD about 380,000, and "Phase Equilibria Diagrams" includes about 31,000 diagrams.
In 2019, the SciGlass data is publicly available on GitHub under the ODC Open Database License (ODbL).
In 2023, the re-emergence of the SciGlass database as SciGlass Sage which offers "AI" assistance, a property Predictor is powered by random forest regression models and the Generator uses the predictive models in conjunction with genetic algorithms.
In 2024, the web database named [https://sciglass.uni-jena.de/ SciGlass Next] is an open-access database designed to bring the largest database of glass properties online. It utilizes the SciGlass data available on GitHub. The database is hosted in the public domain of Friedrich Schiller University Jena.
The website provides comprehensive documentation, including step-by-step instructions and glossaries of properties and symbols used. In addition, both light and dark themes are supported.
Most features are covered, including:
* Glasses: 422,000+ glasses and melts. Sourced from 40,000+ literature sources, including 19,700+ patents.
* Data Tables: Search data and export tables for post-processing.
* Data Visualization: Interactive data visualization with scatter plots, histograms, ternary plots, and curve fitting.
* Authentication: Secured Single Sign-On (SSO) authentication of users.
* ML Predictions (Future): Python-backed ML predictions for glass properties.
* Sidebar Quick Lookup: Categories of patent index, trademark index, author index, subject index, spectral index and glass formation. | 0 | Theoretical and Fundamental Chemistry |
DESs are fluids generally composed of two or three cheap and safe components that are capable of self-association, often through hydrogen bond interactions, to form eutectic mixtures with a melting point lower than that of each individual component. DESs are generally liquid at temperatures lower than 100 °C, and they exhibit similar physico-chemical properties to traditional ILs, while being much cheaper and environmentally friendlier. Most of them are mixtures of choline chloride and a hydrogen-bond donor (e.g., urea, ethylene glycol, malonic acid) or mixtures of choline chloride with a hydrated metal salt. Other choline salts (e.g. acetate, citrate, nitrate) have a much higher costs or need to be synthesised, and the DES formulated from these anions are typically much more viscous and can have higher conductivities than for choline chloride. This results in lower plating rates and poorer throwing power and for this reason chloride-based DES systems are still favoured. For instance, Reline (a 1:2 mixture of choline chloride and urea) has been used to selectively recover Zn and Pb from a mixed metal oxide matrix. Similarly, Ethaline (a 1: 2 mixture of choline chloride and ethylene glycol) facilitates metal dissolution in electropolishing of steels. DESs have also demonstrated promising results to recover metals from complex mixtures such Cu/Zn and Ga/As, and precious metals from minerals. It has also been demonstrated that metals can be recovered from complex mixtures by electrocatalysis using a combination of DESs as lixiviants and an oxidising agent, while metal ions can be simultaneously separated from the solution by electrowinning. | 1 | Applied and Interdisciplinary Chemistry |
A biomolecule or biological molecule is loosely defined as a molecule produced by a living organism and essential to one or more typically biological processes. Biomolecules include large macromolecules such as proteins, carbohydrates, lipids, and nucleic acids, as well as small molecules such as vitamins and hormones. A more general name for this class of material is biological materials. Biomolecules are an important element of living organisms, those biomolecules are often endogenous, produced within the organism but organisms usually need exogenous biomolecules, for example certain nutrients, to survive.
Biology and its subfields of biochemistry and molecular biology study biomolecules and their reactions. Most biomolecules are organic compounds, and just four elements—oxygen, carbon, hydrogen, and nitrogen—make up 96% of the human body's mass. But many other elements, such as the various biometals, are also present in small amounts.
The uniformity of both specific types of molecules (the biomolecules) and of certain metabolic pathways are invariant features among the wide diversity of life forms; thus these biomolecules and metabolic pathways are referred to as "biochemical universals" or "theory of material unity of the living beings", a unifying concept in biology, along with cell theory and evolution theory. | 0 | Theoretical and Fundamental Chemistry |
Immediately after the war, the Soviet Union invaded and occupied northern Korea and took possession of Hansgirgs magnesium and heavy water plants in Hungnam. They transferred the technology back to Russia for integration into their own atomic bomb program. The U.S. Manhattan Project also utilized Hansgirgs electrolytic (CECE) process for heavy water production during the war and for many years thereafter. Many aspects of the postwar history related to both the U.S. and Soviet (now Russian) use of Hansgirg's processes remain classified. | 0 | Theoretical and Fundamental Chemistry |
A number of algorithms for estimating isoelectric points of peptides and proteins have been developed. Most of them use Henderson–Hasselbalch equation with different pK values. For instance, within the model proposed by Bjellqvist and co-workers, the pKs were determined between closely related immobilines by focusing the same sample in overlapping pH gradients. Some improvements in the methodology (especially in the determination of the pK values for modified amino acids) have been also proposed. More advanced methods take into account the effect of adjacent amino acids ±3 residues away from a charged aspartic or glutamic acid, the effects on free C terminus, as well as they apply a correction term to the corresponding pK values using genetic algorithm. Other recent approaches are based on a support vector machine algorithm and pKa optimization against experimentally known protein/peptide isoelectric points.
Moreover, experimentally measured isoelectric point of proteins were aggregated into the databases. Recently, a database of isoelectric points for all proteins predicted using most of the available methods had been also developed.
In practice, a protein with an excess of basic aminoacids (arginine, lysine and/or histidine) will bear an isoelectric point roughly greater than 7 (basic), while a protein with an excess of acidic aminoacids (aspartic acid and/or glutamic acid) will often have an isoelectric point lower than 7 (acidic).
The electrophoretic linear (horizontal) separation of proteins by Ip along a pH gradient in a polyacrylamide gel (also known as isoelectric focusing), followed by a standard molecular weight linear (vertical) separation in a second polyacrylamide gel (SDS-PAGE), constitutes the so called two-dimensional gel electrophoresis or PAGE 2D. This technique allows a thorough separation of proteins as distinct "spots", with proteins of high molecular weight and low Ip migrating to the upper-left part of the bidimensional gel, while proteins with low molecular weight and high Ip locate to the bottom-right region of the same gel. | 0 | Theoretical and Fundamental Chemistry |
Thermal physics, generally speaking, is the study of the statistical nature of physical systems from an energetic perspective. Starting with the basics of heat and temperature, thermal physics analyzes the first law of thermodynamics and second law of thermodynamics from the statistical perspective, in terms of the number of microstates corresponding to a given macrostate. In addition, the concept of entropy is studied via quantum theory.
A central topic in thermal physics is the canonical probability distribution. The electromagnetic nature of photons and phonons are studied which show that the oscillations of electromagnetic fields and of crystal lattices have much in common. Waves form a basis for both, provided one incorporates quantum theory.
Other topics studied in thermal physics include: chemical potential, the quantum nature of an ideal gas, i.e. in terms of fermions and bosons, Bose–Einstein condensation, Gibbs free energy, Helmholtz free energy, chemical equilibrium, phase equilibrium, the equipartition theorem, entropy at absolute zero, and transport processes as mean free path, viscosity, and conduction. | 0 | Theoretical and Fundamental Chemistry |
As in Lewis structures, covalent bonds are indicated by line segments, with a doubled or tripled line segment indicating double or triple bonding, respectively. Likewise, skeletal formulae indicate formal charges associated with each atom (although lone pairs are usually optional, see below). In fact, skeletal formulae can be thought of as abbreviated Lewis structures that observe the following simplifications:
*Carbon atoms are represented by the vertices (intersections or termini) of line segments. For clarity, methyl groups are often explicitly written out as Me or CH, while (hetero)cumulene carbons are frequently represented by a heavy center dot.
* Hydrogen atoms attached to carbon are implied. An unlabeled vertex is understood to represent a carbon attached to the number of hydrogens required to satisfy the octet rule, while a vertex labeled with a formal charge and/or nonbonding electron(s) is understood to have the number of hydrogen atoms required to give the carbon atom these indicated properties. Optionally, acetylenic and formyl hydrogens can be shown explicitly for the sake of clarity.
* Hydrogen atoms attached to a heteroatom are shown explicitly. The heteroatom and hydrogen atoms attached thereto are usually shown as a single group (e.g., OH, NH) without explicitly showing the hydrogen–heteroatom bond. Heteroatoms with simple alkyl or aryl substituents, like methoxy (OMe) or dimethylamino (NMe), are sometimes shown in the same way, by analogy.
* Lone pairs on carbene carbons must be indicated explicitly while lone pairs in other cases are optional and are shown only for emphasis. In contrast, formal charges and unpaired electrons on main-group elements are always explicitly shown.
In the standard depiction of a molecule, the canonical form (resonance structure) with the greatest contribution is drawn. However, the skeletal formula is understood to represent the "real molecule" that is, the weighted average of all contributing canonical forms. Thus, in cases where two or more canonical forms contribute with equal weight (e.g., in benzene, or a carboxylate anion) and one of the canonical forms is selected arbitrarily, the skeletal formula is understood to depict the true structure, containing equivalent bonds of fractional order, even though the delocalized bonds are depicted as nonequivalent single and double bonds. | 0 | Theoretical and Fundamental Chemistry |
In chemistry the polyhedral skeletal electron pair theory (PSEPT) provides electron counting rules useful for predicting the structures of clusters such as borane and carborane clusters. The electron counting rules were originally formulated by Kenneth Wade, and were further developed by others including Michael Mingos; they are sometimes known as Wades rules or the Wade–Mingos rules. The rules are based on a molecular orbital treatment of the bonding. These rules have been extended and unified in the form of the Jemmis mno' rules. | 0 | Theoretical and Fundamental Chemistry |
Tyrosine residues are relatively unreactive; therefore they have not been a popular targets for bioconjugation. Recent development has shown that the tyrosine can be modified through electrophilic aromatic substitutions (EAS) reactions, and it is selective for the aromatic carbon adjacent to the phenolic hydroxyl group. This becomes particularly useful in the case that cysteine residues cannot be targeted. Specifically, diazonium effectively couples with tyrosine residues (diazonium salt shown as reagent in the first reaction in Figure 3 below), and an electron withdrawing substituent in the 4-position of diazonium salt can effectively increase the efficiency of the reaction. Cyclic diazodicarboxyamide derivative like 4-Phenyl-1,2,4-triazole-3,5-dione (PTAD) were reported for selective bioconjugation on tyrosine residues (the second reaction in Figure 3 below). A three-component Mannich-type reaction with aldehydes and anilines (the last reaction in Figure 3) was also described to be relatively tyrosine-selective under mild optimised reaction conditions. | 1 | Applied and Interdisciplinary Chemistry |
In one study a coupling reaction between an indole and a quinone takes place at room temperature without catalyst in water in 82% chemical yield even though reactants and products are insoluble in this medium. The reaction is much less efficient in homogeneous systems such as dichloromethane, toluene and acetonitrile or even the solvent free reaction or even the water reaction but now at 50°C.
The on water effect is also studied in cycloadditions of the type:
In this reaction the alkyne methyl 2-octynoate reacts with triphenylphosphine to an intermediate zwitterionic allenolate, a dipolarophile for the 1,3-dipole 2-phenylnitrone. The primary regioselective [3+2]dipolar cycloaddition product then rearranges to a dihydroisoxazole with regeneration of the phosphine. This reaction only takes place in water with lithium chloride added even though the reactants do not dissolve in this medium. In organic solvents such as toluene or dichloromethane no reaction takes place. | 0 | Theoretical and Fundamental Chemistry |
Heme, an important prosthetic group present in Complexes I, II, and IV can also be targeted, since heme biosynthesis and uptake have been correlated with increased cancer progression. Various molecules can inhibit heme via different mechanisms. For instance, succinylacetone has been shown to decrease heme concentrations by inhibiting δ-aminolevulinic acid in murine erythroleukemia cells. The primary structure of heme-sequestering peptides, such as HSP1 and HSP2, can be modified to downregulate heme concentrations and reduce proliferation of non-small lung cancer cells. | 1 | Applied and Interdisciplinary Chemistry |
In 1991, Korean Chemical Society held the first KChO. Four high school students representing South Korea joined the 24th IChO the next year, which was held in United States. KChO was held 27 times. In 2018, 50th IChO was held at Slovakia, Czech Republic. | 1 | Applied and Interdisciplinary Chemistry |
Hari Reddi received his PhD from the University of Delhi in reproductive endocrinology under the mentorship of M.R.N. Prasad. Reddi did postdoctoral work with [http://www.uchospitals.edu/news/2004/20040602-williams-ashman.html Howard Guy Williams-Ashman] at the Johns Hopkins University School of Medicine. Reddi was also a student of Charles Brenton Huggins, the winner of the 1966 Nobel Prize with Peyton Rous for the endocrine regulation of cancer. | 1 | Applied and Interdisciplinary Chemistry |
After a year in Birmingham doing chemical research, he was appointed head of the chemistry at Blackburn Technical School in Blackburn, Lancashire and was principal from 1908-1920. While at Blackburn was involved in publication of 35 papers in the Journal of the Chemical Society. He did original work on chemical structure and optical isomerism and as a result became a Fellow of the Royal Society (FRS) in 1917. Pickard was Principal of Battersea Polytechnic (which later became the University of Surrey) from 1920 to 1927.
He was also consulted by the cotton industry and later became director of the British Cotton Industry Research Association (then the Shirley Institute) in Manchester from 1927-1943 and expanded the technical facilities extensively in 1936.
He had considerable organisational skills and was active in several scientific organisations including the Royal Society (council); Society of Chemical Industry (president 1932-33); the Royal Institute of Chemistry (now the Royal Society of Chemistry) (president 1936-1939); the Chemical Society (vice-president); the now defunct [http://www.charitycommission.gov.uk/Showcharity/RegisterOfCharities/RemovedCharityMain.aspx?RegisteredCharityNumber=214247&SubsidiaryNumber=0 Chemical Council] (chairman) and various positions over a long period with the University of London including Vice-Chancellor, 1937-1939. | 0 | Theoretical and Fundamental Chemistry |
*First use of radiation chemistry for commercial products by Raychem Corporation in 1957
*Electrolytic production of bromine (also known as the Dow process) by Herbert Henry Dow in 1891 at the Evens Mill in Midland, Michigan
*The Hall-Héroult process for production of aluminum by electrochemistry, discovered by American chemist Charles Martin Hall in 1886 and independently the same year by French chemist Paul Héroult
*Gilman Hall at the University of California, Berkeley, built between 1916 and 1917 in Berkeley, California | 1 | Applied and Interdisciplinary Chemistry |
*[http://civilwarfortifications.com/dictionary/xgr-016.html Pisa Revetment]
*[http://civilwarfortifications.com/dictionary/xgr-022.html Gabion Revetment] | 1 | Applied and Interdisciplinary Chemistry |
The sperm and the egg are incubated together at a ratio of about 75,000:1 in a culture media in order for the actual fertilisation to take place. A review in 2013 came to the result that a duration of this co-incubation of about 1 to 4 hours results in significantly higher pregnancy rates than 16 to 24 hours. In most cases, the egg will be fertilised during co-incubation and will show two pronuclei. In certain situations, such as low sperm count or motility, a single sperm may be injected directly into the egg using intracytoplasmic sperm injection (ICSI). The fertilised egg is passed to a special growth medium and left for about 48 hours until the embryo consists of six to eight cells.
In gamete intrafallopian transfer, eggs are removed from the woman and placed in one of the fallopian tubes, along with the mans sperm. This allows fertilisation to take place inside the womans body. Therefore, this variation is actually an in vivo fertilisation, not in vitro. | 1 | Applied and Interdisciplinary Chemistry |
In order to measure Cu isotope ratios of various materials, several steps must be taken prior to the isotopic measurement in order to extract and purify copper. The first step in the analytical pipeline to measure Cu isotopes is to liberate Cu from its host material. Liberation should be quantitative, otherwise fractionation may be introduced at this step. Cu-containing rocks are generally dissolved with HF; biological materials are commonly digested with HNO. Seawater samples must be concentrated due to the low (nM) concentrations of Cu in the ocean. The sample material is subsequently run through an anion-exchange column to isolated and purify Cu. This step can also introduce Cu isotope fractionation if Cu is not quantitatively recovered from the column. If samples are from seawater, other ions (e.g., Na, Mg, Ca) must be removed in order to eliminate isobaric interferences during the isotope measurement. Prior to 1992, Cu/Cu ratios were measured via thermal ionization mass spectrometry (TIMS). Today, Cu isotopic compositions are measured via multi-conductor inductively coupled plasma mass spectrometry (MC-ICP-MS), which ionizes samples using inductively coupled plasma and introduces smaller errors than TIMS. | 0 | Theoretical and Fundamental Chemistry |
Separating molecules in a solution by dialysis is a relatively straightforward process. Other than the sample and dialysate buffer, all that is typically needed is:
* Dialysis membrane in an appropriate format (e.g., tubing, cassette, etc.) and molecular weight cut-off (MWCO)
* A container to hold the dialysate buffer
* The ability to stir the solutions and control the temperature | 1 | Applied and Interdisciplinary Chemistry |
TI-1 antigens have an intrinsic B cell activating activity, that can directly cause proliferation and differentiation of B lymphocytes without T cell stimulation and independently of their BCR specificity. TI-1 antigens activate B-cells via Toll like receptors, which are expressed in humans on the surface of B lymphocytes after BCR stimulation. TI-1 antigens are classified as B-cell mitogens, because they induce numerous cell divisions. In higher concentrations, TI-1 antigens bind to BCR and TLR of various clones of B lymphocytes, which leads to production of multiclonal antibodies. But when the concentration of TI-1 is lower, it can activate only B lymphocytes with specific binding of TI-1 on their BCR, and leads to production of monoclonal antibodies.
This part of immune response may be important in some early stages of infection by extracellular pathogens, because it is rapidly activated and does not require T cell help or clonal maturation and expansion. An example of TI-1 antigen is lipopolysaccharide (LPS) or bacterial DNA. | 1 | Applied and Interdisciplinary Chemistry |
In a combustion analyser, half of the sample is injected into a chamber where it is acidified, usually with phosphoric acid, to turn all of the inorganic carbon into carbon dioxide as per the following reaction:
: CO + HO ⇌ HCO ⇌H + HCO ⇌ 2H + CO
This is then sent to a detector for measurement. The other half of the sample is injected into a combustion chamber which is raised to between 600–700 °C, some even up to 1200 °C. Here, all the carbon reacts with oxygen, forming carbon dioxide. It is then flushed into a cooling chamber, and finally into the detector. Usually, the detector used is a non-dispersive infrared spectrophotometer. By finding the total inorganic carbon and subtracting it from the total carbon content, the amount of organic carbon is determined. | 0 | Theoretical and Fundamental Chemistry |
Fineness of silver in Britain was traditionally expressed as the mass of silver expressed in troy ounces and pennyweights ( troy ounce) in one troy pound (12 troy ounces) of the resulting alloy. Britannia silver has a fineness of 11 ounces, 10 pennyweights, or about silver, whereas sterling silver has a fineness of 11 ounces, 2 pennyweights, or exactly silver. | 1 | Applied and Interdisciplinary Chemistry |
Next, as a cleansing against different sequencing depths from different runs and other factors that can hinder the fragment length distribution sanity, Bayesian normalization via the Dirichlet-multinomial model should be done. Per every sample, based on the fragment lengths observed in that sample, a multinomial maximum likelihood estimation-based fragment length distribution is generated. Two intervals of 250 base pair length are used, located between -1000th base pair and -750th base pair, and between 750th base pair and 1000th base pair locations to the centre of TSS. This is done due to the prevention of the impact of gene expression on the generated distribution, as the selected intervals are relatively far away from TSS. Then, the fragment length densities from that distribution are sampled for each 201-fragment size and used as a parameter for Dirichlet distribution generation.
The initial parameter for Dirichlet distribution is set to 20. From the obtained Dirichlet distribution, 2000 fragments are sampled, and Shannon's entropy is calculated for those. The Shannon entropies are subsequently compared with the Shannon entropy values of five randomly selected background sets ( where ). | 1 | Applied and Interdisciplinary Chemistry |
A 2012 report from the U.S. National Research Council calls for a new focus on glycoscience, a field that explores the structures and functions of glycans and promises great advances in areas as diverse as medicine, energy generation, and materials science. Until now, glycans have received little attention from the research community due to a lack of tools to probe their often complex structures and properties. The report presents a roadmap for transforming glycoscience from a field dominated by specialists to a widely studied and integrated discipline. | 0 | Theoretical and Fundamental Chemistry |
Okamoto began studying dentistry in 1936. She very soon switched to medicine enrolling at the Tokyo Women's Medical University and graduated in December 1941. | 1 | Applied and Interdisciplinary Chemistry |
The most common way of classifying ordered columnar structures uses the phyllotactic notation, adopted from botany. It is used to describe arrangements of leaves of a plant, pine cones, or pineapples, but also planar patterns of florets in a sunflower head. While the arrangement in the former are cylindrical, the spirals in the latter are arranged on a disk. For columnar structures phyllotaxis in the context of cylindrical structures is adopted.
The phyllotactic notation describes such structures by a triplet of positive integers with . Each number , , and describes a family of spirals in the 3-dimensional packing. They count the number of spirals in each direction until the spiral repeats. This notation, however, only applies to triangular lattices and is therefore restricted to the ordered structures without internal spheres. | 0 | Theoretical and Fundamental Chemistry |
Freweini Mebrahtu () is an Ethiopian chemical engineer and inventor who won the 2019 CNN Hero of the year award for her activism in improving girls' access to education. | 1 | Applied and Interdisciplinary Chemistry |
Stable carbon isotope composition is another widely used proxy for interpreting paleoenvironment conditions. The Surface temperature fluctuation from the Paleocene to Miocene has been established based on carbon isotope data from foraminifera in Antarctic region. The organic matter preserved in sediments records paleoecosystems, and its carbon isotope composition has been also utilized to reconstruct paleoclimatic evolution. For example, Rogers and Koons (1969) have reported that the carbon isotope ratios, derived from organic matter in Quaternary marine sediments in the Gulf of Mexico, correlate well with Pleistocene climate changes.
Chen et al. (2011) have documented ancient climate fluctuations since the last glacial maximum based on soil samples in Tibet. Other sources for organic carbon isotope used as proxies for paleoenvironment reconstruction include lacustrine deposits for lake level variations, fossilized vertebrates for precipitation fluctuations, oil shales for paleoecological and paleoclimate conditions. | 0 | Theoretical and Fundamental Chemistry |
To determine the change in enthalpy in a neutralization reaction (ΔH), a known amount of basic solution may be placed in a calorimeter, and the temperature of this solution alone recorded. Then, a known amount of acidic solution may be added and the change in temperature measured using a thermometer. The difference in temperature (ΔT, in units K or °C) may be calculated by subtracting the initial temperature from the final temperature. The enthalpy of neutralization ΔH may then be calculated according to the following equation:
Regardless of the specific chemical process, with a known calorimeter constant and a known change in temperature the heat added to the system may be calculated by multiplying the calorimeter constant by that change in temperature. | 0 | Theoretical and Fundamental Chemistry |
The Stark effect is at the basis of the spectral shift measured for voltage-sensitive dyes used for imaging of the firing activity of neurons. | 0 | Theoretical and Fundamental Chemistry |
Traces are better known in their fossilized form than in modern sediments. This makes it difficult to interpret some fossils by comparing them with modern traces, even though they may be extant or even common. The main difficulties in accessing extant burrows stem from finding them in consolidated sediment, and being able to access those formed in deeper water.
Trace fossils are best preserved in sandstones; the grain size and depositional facies both contributing to the better preservation. They may also be found in shales and limestones. | 1 | Applied and Interdisciplinary Chemistry |
EMBO Reports is a peer-reviewed scientific journal covering research related to biology at a molecular level. It publishes primary research papers, reviews, and essays and opinion. It also features commentaries on the social impact of advances in the life sciences and the converse influence of society on science. A sister journal to The EMBO Journal, EMBO Reports was established in 2000 and was published on behalf of the European Molecular Biology Organization by Nature Publishing Group since 2003. It is now published by EMBO Press. | 1 | Applied and Interdisciplinary Chemistry |
Wittig reagents are used in organic synthesis. They are derived from phosphonium salts. A strong base such as butyllithium or sodium amide is required for the deprotonation:
:[PhPCHR]X + CHLi → PhP=CHR + LiX + CH
One of the simplest ylides is methylenetriphenylphosphorane (PhP=CH).
The compounds PhPX (X = Cl, Br) are used in the Kirsanov reaction.
The Kinnear–Perren reaction is used to prepare alkylphosphonyl dichlorides (RP(O)Cl) and esters (RP(O)(OR′)). A key intermediate are alkyltrichlorophosphonium salts, obtained by the alkylation of phosphorus trichloride:
:RCl + PCl + AlCl → [RPCl] | 0 | Theoretical and Fundamental Chemistry |
* Vg1 Family
* Activin Family
** Involved in embryogenesis and osteogenesis
** Regulate insulin and pituitary, gonadal, and hypothalamic hormones
** Nerve cell survival factors
**3 Activins: Activin A, Activin B and Activin AB.
* Glial-Derived Neurotrophic Factor (GDNF)
** Needed for kidney and enteric neuron differentiation
* Müllerian Inhibitory Factor
** Involved in mammalian sex determination
* Nodal
** Binds to Activin A Type 2B receptor
** Forms receptor complex with Activin A Type 1B receptor or with Activin A Type 1C receptor.
*Growth and differentiation factors (GDFs) | 1 | Applied and Interdisciplinary Chemistry |
Consumption in the twentieth and twenty-first centuries has been abundantly pushed by automobile sector growth. The 1985–2003 oil glut even fueled the sales of low fuel economy vehicles in OECD countries. The 2008 economic crisis seems to have had some impact on the sales of such vehicles; still, in 2008 oil consumption showed a small increase.
In 2016 Goldman Sachs predicted lower demand for oil due to emerging economies concerns, especially China. The BRICS (Brasil, Russia, India, China, South Africa) countries might also kick in, as China briefly had the largest automobile market in December 2009. In the long term, uncertainties linger; the OPEC believes that the OECD countries will push low consumption policies at some point in the future; when that happens, it will definitely curb oil sales, and both OPEC and the Energy Information Administration (EIA) kept lowering their 2020 consumption estimates during the past five years. A detailed review of International Energy Agency oil projections have revealed that revisions of world oil production, price and investments have been motivated by a combination of demand and supply factors. All together, Non-OPEC conventional projections have been fairly stable the last 15 years, while downward revisions were mainly allocated to OPEC. Upward revisions are primarily a result of US tight oil.
Production will also face an increasingly complex situation; while OPEC countries still have large reserves at low production prices, newly found reservoirs often lead to higher prices; offshore giants such as Tupi, Guara and Tiber demand high investments and ever-increasing technological abilities. Subsalt reservoirs such as Tupi were unknown in the twentieth century, mainly because the industry was unable to probe them. Enhanced Oil Recovery (EOR) techniques (example: DaQing, China) will continue to play a major role in increasing the world's recoverable oil.
The expected availability of petroleum resources has always been around 35 years or even less since the start of the modern exploration. The oil constant, an insider pun in the German industry, refers to that effect.
A growing number of divestment campaigns from major funds pushed by newer generations who question the sustainability of petroleum may hinder the financing of future oil prospection and production. | 0 | Theoretical and Fundamental Chemistry |
Body farms subject donated cadavers to various environmental conditions to study the process of human decomposition. These include The University of Tennessees Forensic Anthropologic Facility, Western Carolina Universities Osteology Research Station (FOREST), Texas State Universitys Forensic Anthropology Research Facility (FARF), Sam Houston State Universitys Southeast Texas Applied Forensic Science Facility (STAFS), Southern Illinois Universitys Complex for Forensic Anthropology Research, and Colorado Mesa University's Forensic Investigation Research Station. The Australian Facility for Taphonomic Experimental Research, near Sydney, is the first body farm located outside of the United States In the United Kingdom there are several facilities which, instead of using human remains or cadavers, use dead pigs to study the decomposition process. Pigs are less likely to have infectious diseases than human cadavers, and are more readily available without any concern for ethical issues, but a human body farm is still highly sought after for further research. Each body farm is unique in its environmental make-up, giving researchers a broader knowledge, and allowing research into how different environmental factors can affect the rate of decomposition significantly such as humidity, sun exposure, rain or snow, altitude level and more. | 1 | Applied and Interdisciplinary Chemistry |
In thermodynamics, the chemical potential of a species is the energy that can be absorbed or released due to a change of the particle number of the given species, e.g. in a chemical reaction or phase transition. The chemical potential of a species in a mixture is defined as the rate of change of free energy of a thermodynamic system with respect to the change in the number of atoms or molecules of the species that are added to the system. Thus, it is the partial derivative of the free energy with respect to the amount of the species, all other species' concentrations in the mixture remaining constant. When both temperature and pressure are held constant, and the number of particles is expressed in moles, the chemical potential is the partial molar Gibbs free energy. At chemical equilibrium or in phase equilibrium, the total sum of the product of chemical potentials and stoichiometric coefficients is zero, as the free energy is at a minimum. In a system in diffusion equilibrium, the chemical potential of any chemical species is uniformly the same everywhere throughout the system.
In semiconductor physics, the chemical potential of a system of electrons at zero absolute temperature is known as the Fermi level. | 0 | Theoretical and Fundamental Chemistry |
The grain size, shape and distribution of the foundry sand, the type and quantity of bonding materials, the density to which the sand is rammed, and the percentage of moisture used for tempering the sand are important factors in regulating the degree of permeability. | 1 | Applied and Interdisciplinary Chemistry |
Persephin has the potential to be used as a therapeutic treatment for neurodegenerative diseases, such as Parkinson's disease and other diseases that affect motor neurons. Because persephin acts more selectively compared to other GFLs, such as GDNF, it may produce fewer mechanism-based complications, making it a stronger therapeutic target. | 1 | Applied and Interdisciplinary Chemistry |
As mentioned, Gram-negative bacteria primarily use acylated homoserine lactones (AHLs) as autoinducer molecules. The minimum quorum sensing circuit in Gram-negative bacteria consists of a protein that synthesizes an AHL and a second, different protein that detects it and causes a change in gene expression. First identified in V. fischeri, these two such proteins are LuxI and LuxR, respectively. Other Gram-negative bacteria use LuxI-like and LuxR-like proteins (homologs), suggesting a high degree of evolutionary conservation. However, among Gram-negatives, the LuxI/LuxI-type circuit has been modified in different species. Described in more detail below, these modifications reflect bacterial adaptations to grow and respond to particular niche environments. | 1 | Applied and Interdisciplinary Chemistry |
Bioelectrochemistry is a branch of electrochemistry and biophysical chemistry concerned with electrophysiological topics like cell electron-proton transport, cell membrane potentials and electrode reactions of redox enzymes. | 0 | Theoretical and Fundamental Chemistry |
In 2020, the first cloned Przewalski's horse was born, the result of a collaboration between San Diego Zoo Global, ViaGen Equine and Revive & Restore. The cloning was carried out by somatic cell nuclear transfer (SCNT), whereby a viable embryo is created by transplanting the DNA-containing nucleus of a somatic cell into an immature egg cell (oocyte) that has had its own nucleus removed, producing offspring genetically identical to the somatic cell donor. Since the oocyte used was from a domestic horse, this was an example of interspecies SCNT.
The somatic cell donor was a Przewalskis horse stallion named Kuporovic, born in the UK in 1975, and relocated three years later to the US, where he died in 1998. Due to concerns over the loss of genetic variation in the captive Przewalskis horse population, and in anticipation of the development of new cloning techniques, tissue from the stallion was cryopreserved at the San Diego Zoos Frozen Zoo. Breeding of this individual in the 1980s had already substantially increased the genetic diversity of the captive population, after he was discovered to have more unique alleles than any other horse living at the time, including otherwise-lost genetic material from two of the original captive founders. To produce the clone, frozen skin fibroblasts were thawed, and grown in cell culture. An oocyte was collected from a domestic horse, and its nucleus replaced by a nucleus collected from a cultured Przewalskis horse fibroblast. The resulting embryo was induced to begin division and was cultured until it reached the blastocyst stage, then implanted into a domestic horse surrogate mare, which carried the embryo to term and delivered a foal with the Przewalski's horse DNA of the long-deceased stallion.
The cloned horse was named Kurt, after Dr. Kurt Benirschke, a geneticist who developed the idea of cryopreserving genetic material from species considered to be endangered. His ideas led to the creation of the Frozen Zoo as a genetic library. There is a breeding herd in the San Diego Zoo Safari Park. Once the foal matures, he will be relocated to the breeding herd at the San Diego Zoo Safari Park, so as to pass Kuporovics genes into the larger captive Przewalskis horse population and increase the genetic variation of the species. | 1 | Applied and Interdisciplinary Chemistry |
In vertebrates, the majority of gene promoters contain a CpG island with numerous CpG sites. When many of a gene's promoter CpG sites are methylated the gene becomes silenced. Colorectal cancers typically have 3 to 6 driver mutations and 33 to 66 hitchhiker or passenger mutations. However, transcriptional silencing may be of more importance than mutation in causing progression to cancer. For example, in colorectal cancers about 600 to 800 genes are transcriptionally silenced by CpG island methylation (see regulation of transcription in cancer). Transcriptional repression in cancer can also occur by other epigenetic mechanisms, such as altered expression of microRNAs. In breast cancer, transcriptional repression of BRCA1 may occur more frequently by over-expressed microRNA-182 than by hypermethylation of the BRCA1 promoter (see Low expression of BRCA1 in breast and ovarian cancers). | 1 | Applied and Interdisciplinary Chemistry |
Hydroamination could find applications due to the valuable nature of the resulting amine, as well as the greenness of the process. Functionalized allylamines, which can be produced through hydroamination, have extensive pharmaceutical application, although presently such species are not prepared by hydroamination. Hydroamination has been utilized to synthesize the allylamine Cinnarizine in quantitative yield. Cinnarizine treats both vertigo and motion sickness related nausea.
Hydroamination is also promising for the synthesis of alkaloids. An example was the hydroamination step used in the total synthesis of (-)-epimyrtine. | 0 | Theoretical and Fundamental Chemistry |
Vital effects are biological impacts on geochemical records. Many marine organisms, ranging from zooplankton (e.g. foraminifera) to phytoplankton (e.g diatoms) to reef builders (e.g. coral), create shells or skeletons from chemical compounds dissolved in seawater. This process, which is also called biomineralization, therefore records the chemical signature of seawater during the time of shell formation. However, different species have different metabolism and physiology, causing them to create their shells in different ways. These biological distinctions cause species to record slightly different chemical signatures in their shells; these differences are known as vital effects. | 0 | Theoretical and Fundamental Chemistry |
The first attempt of LBMS tried to use a Boltzmann-like equation for force (vectorial) distributions. The approach requires more computational memory but results are obtained in fracture and solid cracking. | 0 | Theoretical and Fundamental Chemistry |
A study demonstrates how the autocrine production of the IL-7 cytokine mediated by T-cell acute lymphoblastic leukemia (T-ALL) can be involved in the oncogenic development of T-ALL and offer novel insights into T-ALL spreading. | 1 | Applied and Interdisciplinary Chemistry |
ArcB is a membrane-bound sensor histidine kinase. It is unusual in that it contains three distinct signaling domains. It senses oxygen levels in the cell by interacting with reduced quinone. When reduced quinone levels are high, it signals that the cell is engaged in aerobic respiration. When reduced quinone levels are low, it signals that the cells is unable to perform aerobic respiration. This is typically due to insufficient levels of oxygen, which acts as the terminal electron receptor in the electron transport chain. ArcB is then able to activate or deactivate ArcA, the response regulator, which can then travel to the chromosome and regulate gene expression.
ArcA is activated via phosphorylation. When oxygen is present in the cell ArcB autophosphorylates. This inorganic phosphate is then transferred via a four amino acid phosphorelay to ArcA. Phosphorylated ArcA is then able to attach to specific, consensus gene sequences on the chromosome regulating approximately 30 different operons. ArcA is able to acts as both a repressor and an activator depending on which operon it attaches.
When oxygen levels are low, ArcB acts as a phosphatase, removing the inorganic phosphate group from ArcA. Without the attached phosphate group, ArcA is unable to bind to DNA and genes return to their original, aerobic levels of expression. This allows the cell to engage in metabolic pathways that are most advantageous for the current conditons of the cell. Dephosphorylation utilizes the same phosphorelay as phosphorylation, but it is operated in reverse.
Without the Arc system being present throughout various strains of anaerobic bacteria, gene expression could not efficiently control the metabolism during the replication of genetic material. Under many growth conditions where oxygen is not present, the ArcB sensor kinase (which is membrane-bound) turns to autophosphorylates which is a process proven to be more efficient when certain fermenting metabolites such as Pyruvate, Acetate, and D-Lactate. | 1 | Applied and Interdisciplinary Chemistry |
Biogenic calcium carbonate is formed when marine organisms, such as coccolithophores, corals, pteropods, and other mollusks transform calcium ions and bicarbonate into shells and exoskeletons of calcite or aragonite, both forms of calcium carbonate. This is the dominant sink for dissolved calcium in the ocean. Dead organisms sink to the bottom of the ocean, depositing layers of shell which over time cement to form limestone. This is the origin of both marine and terrestrial limestone.
Calcium precipitates into calcium carbonate according to the following equation:
Ca + 2HCO → CO+ HO + CaCO
The relationship between dissolved calcium and calcium carbonate is affected greatly by the levels of carbon dioxide (CO) in the atmosphere.
Increased carbon dioxide leads to more bicarbonate in the ocean according to the following equation:
CO + CO + HO → 2HCO
With ocean acidification, inputs of carbon dioxide promote the dissolution of calcium carbonate and harm marine organisms dependent on their protective calcite or aragonite shells. The solubility of calcium carbonate increases with pressure and carbon dioxide and decreases with temperature. Thus, calcium carbonate is more soluble in deep waters than surface waters due to higher pressure and lower temperature. As a result, precipitation of calcium carbonate is more common in shallower oceans. The depth at which the rate of calcite dissolution equals the rate of calcite precipitation is known as calcite compensation depth. | 1 | Applied and Interdisciplinary Chemistry |
Sewage treatment often involves two main stages, called primary and secondary treatment, while advanced treatment also incorporates a tertiary treatment stage with polishing processes. Different types of sewage treatment may utilize some or all of the process steps listed below. | 1 | Applied and Interdisciplinary Chemistry |
The electronic transitions of molecules in solution can depend strongly on the type of solvent with additional bathochromic shifts or hypsochromic shifts. | 0 | Theoretical and Fundamental Chemistry |
NF-kB is a transcription factor that can be activated by p75NTR. Nerve growth factor (NGF) is a neurotrophin that promotes neuronal growth, and, in the absence of NGF, neurons die. Neuronal death in the absence of NGF can be prevented by NF-kB activation. Phosphorylated IκB kinase binds to and activates NF-kB before separating from NF-kB. After separation, IκB degrades and NF-kB continues to the nucleus to initiate pro-survival transcription. NF-kB also promotes neuronal survival in conjunction with NGF.
NF-kB activity is activated by p75NTR, and is not activated via Trk receptors. NF-kB activity does not effect Brain-derived neurotrophic factor promotion of neuronal survival. | 1 | Applied and Interdisciplinary Chemistry |
In 1961, Nesmeyanov formulated the idea of obtaining food by synthetic methods, bypassing agriculture. The idea was based on the works of D. I. Mendeleev and M. Berthelot , as well as an awareness of the modern possibilities of organic synthesis, the problems of preserving the environment and the efficiency of food production. The main areas of work were: the development of highly efficient methods for obtaining nutrients; reproduction of the appearance, taste, smell, color, shape, consistency and other properties of natural products in synthetic food substances. As a result of research at INEOS , processes have been developed for obtaining black caviar, new forms of potato products, pasta and cereals and combined meat products based on vegetable and animal proteins. | 0 | Theoretical and Fundamental Chemistry |
Fission track dating is a radiometric dating technique based on analyses of the damage trails, or tracks, left by fission fragments in certain uranium-bearing minerals and glasses. Fission-track dating is a relatively simple method of radiometric dating that has made a significant impact on understanding the thermal history of continental crust, the timing of volcanic events, and the source and age of different archeological artifacts. The method involves using the number of fission events produced from the spontaneous decay of uranium-238 in common accessory minerals to date the time of rock cooling below closure temperature. Fission tracks are sensitive to heat, and therefore the technique is useful at unraveling the thermal evolution of rocks and minerals. Most current research using fission tracks is aimed at: a) understanding the evolution of mountain belts; b) determining the source or provenance of sediments; c) studying the thermal evolution of basins; d) determining the age of poorly dated strata; and e) dating and provenance determination of archeological artifacts.
In the 1930s it was discovered that uranium (specifically U-235) would undergo fission when struck by neutrons. This caused damage tracks in solids which could be revealed by chemical etching. | 0 | Theoretical and Fundamental Chemistry |
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* Hamashima Y, Sawada D, Kanai M, Shibasaki M: A new bifunctional asymmetric catalysis: An efficient catalytic asymmetric cyanosilylation of aldehydes, Journal of the American Chemical Society 121 (1999) 2641–2642.
* Bougauchi M, Watanabe S, Arai T, Sasai H, Shibasaki M: Catalytic asymmetric epoxidation of alpha,beta-unsaturated ketones promoted by lanthanoid complexes, Journal of the American Chemical Society 119 (1997) 2329–2330.
* Arai T, Sasai H, Aoe K, Okamura K, Date T, Shibasaki M: A new multifunctional heterobimetallic asymmetric catalyst for Michael additions and tandem Michael-Aldol reactions, Angewandte Chemie-International Edition in English 35 (1996) 104–106.
His research interests are focussed on the development of new synthetic methods, the design of biologically significant compounds and synthetic studies of such compounds. | 0 | Theoretical and Fundamental Chemistry |
Under normal conditions, small disk-shape platelets circulate in the blood freely and without interaction with one another. ADP is stored in dense bodies inside blood platelets and is released upon platelet activation. ADP interacts with a family of ADP receptors found on platelets (P2Y1, P2Y12, and P2X1), which leads to platelet activation.
* P2Y1 receptors initiate platelet aggregation and shape change as a result of interactions with ADP.
* P2Y12 receptors further amplify the response to ADP and draw forth the completion of aggregation.
ADP in the blood is converted to adenosine by the action of ecto-ADPases, inhibiting further platelet activation via adenosine receptors. | 1 | Applied and Interdisciplinary Chemistry |
As of 2017, the strongest limits on neutrinoless double beta decay have come from GERDA in Ge, CUORE in Te, and EXO-200 and KamLAND-Zen in Xe. | 0 | Theoretical and Fundamental Chemistry |
Born on 13 June 1923, Corbett was the son of Walter Corbett and Margaret Whitehead Corbett (née Robertson). He studied at the University of Otago, graduating Master of Science with first-class honours in chemistry in 1945. Corbett later undertook doctoral studies at the University of Cambridge under Alexander Todd on the structures of some of the metabolites—puberulic acid, puberulonic acid, and stipitatic acid—of Penicillium species. He showed that they contain the tropolone skeleton, and his PhD thesis, titled The structure of certain antibiotics was completed in 1950.
In 1949, Corbett married Enid Mary Carter in Cambridge, England, and they went on to have two children. | 0 | Theoretical and Fundamental Chemistry |
Polyhydroxyalkanoates (PHA) are linear polyesters produced in nature by bacterial fermentation of sugar or lipids. They are produced by the bacteria to store carbon and energy. In industrial production, the polyester is extracted and purified from the bacteria by optimizing the conditions for the fermentation of sugar. More than 150 different monomers can be combined within this family to give materials with extremely different properties. PHA is more ductile and less elastic than other plastics, and it is also biodegradable. These plastics are being widely used in the medical industry. | 0 | Theoretical and Fundamental Chemistry |
Radiopharmaceuticals, or medicinal radiocompounds, are a group of pharmaceutical drugs containing radioactive isotopes. Radiopharmaceuticals can be used as diagnostic and therapeutic agents. Radiopharmaceuticals emit radiation themselves, which is different from contrast media which absorb or alter external electromagnetism or ultrasound. Radiopharmacology is the branch of pharmacology that specializes in these agents.
The main group of these compounds are the radiotracers used to diagnose dysfunction in body tissues. While not all medical isotopes are radioactive, radiopharmaceuticals are the oldest and remain the most common of such drugs. | 0 | Theoretical and Fundamental Chemistry |
Bis(allyl)nickel is an organonickel compound with the formula Ni(η-CH). The molecule consists of two allyl ligands bound to nickel(II). It has inversion symmetry. It is a volatile yellow liquid at room temperature. | 0 | Theoretical and Fundamental Chemistry |
Mutations that affect the functioning of the integrated stress response may have debilitating effects on cells. For example, cells lacking the ATF4 gene are unable to elicit proper gene expression in response to stressors. This results in cells exhibiting issues with amino acid transport, glutathione biosynthesis and oxidative stress resistance. When a mutation inhibits the functioning of PERK, endogenous peroxides accumulate when the cell experiences endoplasmic reticulum stress. In mice and humans lacking PERK, there have been observed destruction of secretory cells undergoing high endoplasmic reticulum stress. | 1 | Applied and Interdisciplinary Chemistry |
Dihydroxyacetone phosphate (DHAP, also glycerone phosphate in older texts) is the anion with the formula HOCHC(O)CHOPO. This anion is involved in many metabolic pathways, including the Calvin cycle in plants and glycolysis. It is the phosphate ester of dihydroxyacetone. | 0 | Theoretical and Fundamental Chemistry |
Synthesis of bioconjugates involves a variety of challenges, ranging from the simple and nonspecific use of a fluorescent dye marker to the complex design of antibody drug conjugates. Various bioconjugation reactions have been developed to chemically modify proteins. Common types of bioconjugation reactions on proteins are coupling of lysine, cysteine, and tyrosine amino acid residues, as well as modification of tryptophan residues and of the N- and C- terminus.
However, these reactions often lack chemoselectivity and efficiency, because they depend on the presence of native amino acids, which are present in large quantities that hinder selectivity. There is an increasing need for chemical strategies that can effectively attach synthetic molecules site specifically to proteins. One strategy is to first install a unique functional group onto a protein, and then a bioorthogonal reaction is used to couple a biomolecule with this unique functional group. The bioorthogonal reactions targeting non-native functional groups are widely used in bioconjugation chemistry. Some important reactions are modification of ketone and aldehydes, Staudinger ligation with organic azides, copper-catalyzed Huisgen cycloaddition of azides, and strain promoted Huisgen cycloaddition of azides. | 1 | Applied and Interdisciplinary Chemistry |
Senftleben was born in Bremen. After graduating from the König-Wilhelm-Gymnasium in Breslau, Senftleben studied physics at the University of Breslau and received his doctorate with Rudolf Ladenburg. The dissertation was about the glow of flames, which he attributed in part to light scattering from small particles in the flame. He was then an assistant in Breslau (with Carl Hintze, Arnold Eucken and Otto Lummer) and Marburg (with Clemens Schaefer), where he habilitated in 1924 and became a privatdozent at University of Marburg. From 1935 until his retirement in 1958 he was a full professor at the University of Münster. He also conducted research there from 1946 to 1961 as an employee at the Marl Chemical Park.
Stimulated by Eucken, he turned to physical chemistry in the 1930s. Among other things, he researched on the direct proof of the dissociation of molecules by collisions of the second kind, the course of the reaction in the production of hydrogen and the electron affinity of oxygen. In particular, however, he investigated the conduction of heat in gases.
The Senftleben-Beenakker effects are named after him and Jan Beenakker, the influence of electric and magnetic fields on the transport properties (thermal conductivity, viscosity) of molecular gases. | 0 | Theoretical and Fundamental Chemistry |
Solid-state NMR (ssNMR) spectroscopy is a technique for characterizing atomic level structure in solid materials e.g. powders, single crystals and amorphous samples and tissues using nuclear magnetic resonance (NMR) spectroscopy. The anisotropic part of many spin interactions are present in solid-state NMR, unlike in solution-state NMR where rapid tumbling motion averages out many of the spin interactions. As a result, solid-state NMR spectra are characterised by larger linewidths than in solution state NMR, which can be utilized to give quantitative information on the molecular structure, conformation and dynamics of the material. Solid-state NMR is often combined with magic angle spinning to remove anisotropic interactions and improve the resolution as well as the sensitivity of the technique. | 0 | Theoretical and Fundamental Chemistry |
From 1996 to 2004, researchers in the European Project for Ice Coring in Antarctica (EPICA) project were able to drill and analyze gases trapped in the ice cores in Antarctica to reconstruct GHG concentrations in the atmosphere over the past 800,000 years". They found that prior to approximately 900,000 years ago, the cycle of ice ages followed by relatively short warm periods lasted about 40,000 years, but by 800,000 years ago the time interval changed dramatically to cycles that lasted 100,000 years. There were low values of GHG in ice ages, and high values during the warm periods.
This 2016 EPA illustration above is a compilation of paleoclimatology showing methane concentrations over time based on analysis of gas bubbles from EPICA Dome C, Antarcticaapproximately 797,446 BCE to 1937 CE, Law Dome, Antarcticaapproximately 1008 CE to 1980 CE Cape Grim, Australia1985 CE to 2015 CE Mauna Loa, Hawaii1984 CE to 2015 CE and Shetland Islands, Scotland: 1993 CE to 2001 CE
The massive and rapid release of large volumes of methane gas from such sediments into the atmosphere has been suggested as a possible cause for rapid global warming events in the Earth's distant past, such as the Paleocene–Eocene Thermal Maximum, and the Great Dying.
In 2001, NASAs Goddard Institute for Space Studies and Columbia Universitys Center for Climate Systems Research scientists confirmed that other greenhouse gases apart from carbon dioxide were important factors in climate change in research presented at the annual meeting of the American Geophysical Union (AGU). They offered a theory on the 100,000-year long Paleocene–Eocene Thermal Maximum that occurred approximately 55 million years ago. They posited that there was a vast release of methane that had previously been kept stable through "cold temperatures and high pressure...beneath the ocean floor". This methane release into the atmosphere resulted in the warming of the earth. A 2009 journal article in Science, confirmed NASA research that the contribution of methane to global warming had previously been underestimated.
Early in the Earths history carbon dioxide and methane likely produced a greenhouse effect. The carbon dioxide would have been produced by volcanoes and the methane by early microbes. During this time, Earths earliest life appeared. According to a 2003 article in the journal Geology, these first, ancient bacteria added to the methane concentration by converting hydrogen and carbon dioxide into methane and water. Oxygen did not become a major part of the atmosphere until photosynthetic organisms evolved later in Earth's history. With no oxygen, methane stayed in the atmosphere longer and at higher concentrations than it does today. | 1 | Applied and Interdisciplinary Chemistry |
The exhaust gas contains water vapor and carbon dioxide which both have lower heat capacity ratio than air. Adding exhaust gas therefore reduces pressure and temperature during the isentropic compression in the cylinder, thereby lowering the adiabatic flame temperature.
In a typical automotive spark-ignited (SI) engine, 5% to 15% of the exhaust gas is routed back to the intake as EGR. The maximum quantity is limited by the need of the mixture to sustain a continuous flame front during the combustion event; excessive EGR in poorly set up applications can cause misfires and partial burns. Although EGR does measurably slow combustion, this can largely be compensated for by advancing spark timing. The impact of EGR on engine efficiency largely depends on the specific engine design, and sometimes leads to a compromise between efficiency and emissions. In certain types of situations, a properly operating EGR can theoretically increase the efficiency of gasoline engines via several mechanisms:
* Reduced throttle losses. The addition of inert exhaust gas into the intake system means that for a given power output, the throttle plate must be opened further, resulting in increased inlet manifold pressure and reduced throttling losses.
* Reduced heat rejection. Lowered peak combustion temperatures not only reduces formation, it also reduces the loss of thermal energy to combustion chamber surfaces, leaving more available for conversion to mechanical work during the expansion stroke.
* Reduced chemical dissociation. The lower peak temperatures result in more of the released energy remaining as sensible energy near Top Dead Center (TDC), rather than being bound up (early in the expansion stroke) in the dissociation of combustion products. This effect is minor compared to the first two.
EGR is typically not employed at high loads because it would reduce peak power output. This is because it reduces the intake charge density. EGR is also omitted at idle (low-speed, zero load) because it would cause unstable combustion, resulting in rough idle.
Since the EGR system recirculates a portion of exhaust gases, over time the valve can become clogged with carbon deposits, which will prevent it from operating properly. Clogged EGR valves can sometimes be cleaned, but replacement is necessary if the valve is faulty. | 1 | Applied and Interdisciplinary Chemistry |
There are several methods for cell lysis, including alkaline lysis, mechanical lysis, and enzymatic lysis. | 1 | Applied and Interdisciplinary Chemistry |
The original bisphosphonates (first generation) were simple molecules with small groups of single atoms or alkyl chains in position R and R. They only had a rather weak inhibiting effect on bone resorption. The inclusion of an amino group marked the beginning of the second generation of bisphosphonates with higher potency. The first was pamidronate and similar analogues followed where the position of the nitrogen in the side chain was the key to a more potent drug. Later it became apparent that the nitrogen does not necessarily have to be connected to an alkyl chain but instead using a heterocyclic group. A few such drugs have been developed and placed on the market where zoledronate is the most notable one. Minodronic acid is even more potent and has been placed on the market in Japan. Their potency is such that it is effective even in picomolar concentration.
Further development has not resulted in the placing on the market of compounds in equal potency. Arylalkyl substitutes of pamidronate are among the most recent bisphosphonates to be used clinically where the hydroxyl group in position R has been omitted to ensure stability.
Recent research in this area has opened up an opportunity to develop new bisphosphonate drug therapies.
Bisphosphonates with a more lipophilic character have been developed and have shown potential as a tumor suppressant. They operate by a slightly different mechanism in which they not only inhibit the key enzyme farnesyl pyrophosphate synthase (FPPS) of the mevalonate pathway but also geranylgeranyl pyrophosphate synthase (GGPS), an enzyme also located in the mevalonate pathway. They do not have the same affinity for the bone minerals.
GGPS has since been successfully inhibited by a novel bisphosphonate compound with a triazole group within R and a methyl group in R. This may become useful in therapies against malignancies like multiple myeloma.
In 2018, a dendritic bisphosphonate was introduced containing three bisphosphonate units. It has shown potential for bone specific delivery of large therapeutic molecules by taking advantage of the high affinity of bisphosphonates to the bone minerals | 1 | Applied and Interdisciplinary Chemistry |
Charles' law states that:
Therefore,
* , or
* , or
where "V" is the volume of a gas, "T" is the absolute temperature and k is a proportionality constant (which is not the same as the proportionality constants in the other equations in this article). | 0 | Theoretical and Fundamental Chemistry |
Diazo compounds can be obtained in an elimination reaction of N-alkyl-N-nitroso compounds, such as in the synthesis of diazomethane from Diazald or MNNG:
(The mechanism shown here is one possibility. For an alternative mechanism for the analogous formation of diazomethane from an N-nitrososulfonamide, see the page on Diazald.) | 0 | Theoretical and Fundamental Chemistry |
Interpolymer complexes (IPC) are the products of non-covalent interactions between complementary unlike macromolecules in solutions. There are foiur types of these complexes:
* Interpolyelectrolyte complexes (IPEC) or polyelectrolyte complexes (PEC)
* Hydrogen-bonded interpolymer complexes
* Stereocomplexes
* Charge-transfer complexes | 0 | Theoretical and Fundamental Chemistry |
The Ripper Method is commonly used in wine making applications as SO is often added to wine to maintain its freshness and the concentration needs to be determined. The technique is not precise and is prone to systematic error as well. This limits its use, despite being a fast and inexpensive test. | 0 | Theoretical and Fundamental Chemistry |
π-donor or σ-donor ligands with small interactions with the metal orbitals lead to a weak ligand field which increases the energies of t orbitals. These molecular orbitals become non-bonding or weakly anti-bonding orbitals (small Δ). Therefore, addition or removal of electron has little effect on complex stability. In this case, there is no restriction on the number of d-electrons and complexes with 12–22 electrons are possible. Small Δ makes filling e* possible (>18 e) and π-donor ligands can make t antibonding (). These types of ligand are located in the low-to-medium part of the spectrochemical series. For example: [TiF] (Ti(IV), d, 12 e), [Co(NH)] (Co(III), d, 18 e), [Cu(OH)] (Cu(II), d, 21 e).
In terms of metal ions, Δ increases down a group as well as with increasing oxidation number. Strong ligand fields lead to low-spin complexes which cause some exceptions to the 18-electron rule. | 0 | Theoretical and Fundamental Chemistry |
The nitrogen cycle is as important in the ocean as it is on land. While the overall cycle is similar in both cases, there are different players and modes of transfer for nitrogen in the ocean. Nitrogen enters the ocean through precipitation, runoff, or as N from the atmosphere. Nitrogen cannot be utilized by phytoplankton as N so it must undergo nitrogen fixation which is performed predominantly by cyanobacteria. Without supplies of fixed nitrogen entering the marine cycle, the fixed nitrogen would be used up in about 2000 years. Phytoplankton need nitrogen in biologically available forms for the initial synthesis of organic matter. Ammonia and urea are released into the water by excretion from plankton. Nitrogen sources are removed from the euphotic zone by the downward movement of the organic matter. This can occur from sinking of phytoplankton, vertical mixing, or sinking of waste of vertical migrators. The sinking results in ammonia being introduced at lower depths below the euphotic zone. Bacteria are able to convert ammonia to nitrite and nitrate but they are inhibited by light so this must occur below the euphotic zone. Ammonification or mineralization is performed by bacteria to convert organic nitrogen to ammonia. Nitrification can then occur to convert the ammonium to nitrite and nitrate. Nitrate can be returned to the euphotic zone by vertical mixing and upwelling where it can be taken up by phytoplankton to continue the cycle. N can be returned to the atmosphere through denitrification.
Ammonium is thought to be the preferred source of fixed nitrogen for phytoplankton because its assimilation does not involve a redox reaction and therefore requires little energy. Nitrate requires a redox reaction for assimilation but is more abundant so most phytoplankton have adapted to have the enzymes necessary to undertake this reduction (nitrate reductase). There are a few notable and well-known exceptions that include most Prochlorococcus and some Synechococcus that can only take up nitrogen as ammonium.
Phosphorus is an essential nutrient for plants and animals. Phosphorus is a limiting nutrient for aquatic organisms. Phosphorus forms parts of important life-sustaining molecules that are very common in the biosphere. Phosphorus does enter the atmosphere in very small amounts when the dust is dissolved in rainwater and seaspray but remains mostly on land and in rock and soil minerals. Eighty per cent of the mined phosphorus is used to make fertilizers. Phosphates from fertilizers, sewage and detergents can cause pollution in lakes and streams. Over-enrichment of phosphate in both fresh and inshore marine waters can lead to massive algae blooms which, when they die and decay leads to eutrophication of freshwaters only. Recent research suggests that the predominant pollutant responsible for algal blooms in saltwater estuaries and coastal marine habitats is nitrogen.
Phosphorus occurs most abundantly in nature as part of the orthophosphate ion (PO), consisting of a P atom and 4 oxygen atoms. On land most phosphorus is found in rocks and minerals. Phosphorus-rich deposits have generally formed in the ocean or from guano, and over time, geologic processes bring ocean sediments to land. Weathering of rocks and minerals release phosphorus in a soluble form where it is taken up by plants, and it is transformed into organic compounds. The plants may then be consumed by herbivores and the phosphorus is either incorporated into their tissues or excreted. After death, the animal or plant decays, and phosphorus is returned to the soil where a large part of the phosphorus is transformed into insoluble compounds. Runoff may carry a small part of the phosphorus back to the ocean. | 0 | Theoretical and Fundamental Chemistry |
Preparations of levocetirizine are sold under the following brand names:
* Xyzal in Australia, Austria, Bulgaria, Croatia, Cyprus, Czech Republic, Finland, France, Hong Kong, Hungary, India, Ireland (also Rinozal), Italy, Japan, Lithuania, Netherlands, Poland, Portugal, Romania, Taiwan, Thailand, Turkey, The Philippines, Serbia, Singapore, Slovakia, Slovenia, South Africa, Switzerland and UK. In May 2007, the US Food and Drug Administration approved Xyzal, where it is co-marketed by Sanofi-Aventis.
* Xazal in Spain.
* Zobral in Cyprus.
* Levobert in India.
* Xusal in Germany and Mexico.
* Xozal in Greece.
* Degraler in Chile.
* Allevo in Egypt.
* Zilola, Histisynt, and Xyzal (UCB) in Hungary.
* Alcet, Curin, and Seasonix in Bangladesh.
* Vozet and Uvnil in India.
* T-Day Syrup in Pakistan.
* Curin in Nepal.
* Zenaro in the Czech Republic and Slovakia.
* Xuzal and Zival in Chile.
* Cezera, Levosetil, Robenan, and Xyzal in Serbia.
* Rinozal and Xyzal in Ireland.
* Xycet in Morocco. | 0 | Theoretical and Fundamental Chemistry |
*Davis, Mackenzie Leo, and David A. Cornwell. Introduction to Environmental Engineering. Dubuque, IA: McGraw-Hill Companies, 2008. Print.
*Gray, N. F. Biology of Wastewater Treatment. London: Imperial College, 2004. Print.
*Davis, Mackenzie Leo, and David A. Cornwell. Introduction to Environmental Engineering. Boston, MA: WCB McGraw-Hill, 1998. Print.
*http://www.cee.mtu.edu/~nurban/classes/CE3502/spring12/modelreports/MLSSreport.pdf
*http://ragsdaleassociates.com/WastewaterSystemOperatorsManual/Chapter%208%20-%20Activated%20Sludge.pdf | 0 | Theoretical and Fundamental Chemistry |
LongSAGE was a more robust version of the original SAGE developed in 2002 which had a higher throughput, using 20 μg of mRNA to generate a cDNA library of thousands of tags. Robust LongSage (RL-SAGE) Further improved on the LongSAGE protocol with the ability to generate a library with an insert size of 50 ng mRNA, much smaller than previous LongSAGE insert size of 2 μg mRNA and using a lower number of ditag polymerase chain reactions (PCR) to obtain a complete cDNA library. | 1 | Applied and Interdisciplinary Chemistry |
Paramyxoviruses are a diverse family of non-segmented negative strand RNA viruses that include many highly pathogenic viruses affecting humans, animals, and birds. These include canine distemper virus (dogs), phocine distemper virus (seals), cetacean morbillivirus (dolphins and porpoises) Newcastle disease virus (birds) and rinderpest virus (cattle). Some paramyxoviruses such as the henipaviruses are zoonotic pathogens, occurring primarily in an animal hosts, but also able to infect humans. | 1 | Applied and Interdisciplinary Chemistry |
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