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The nitrogen in ammonia has 5 valence electrons and bonds with three hydrogen atoms to complete the octet. This would result in the geometry of a regular tetrahedron with each bond angle equal to cos(−) ≈ 109.5°. However, the three hydrogen atoms are repelled by the electron lone pair in a way that the geometry is distorted to a trigonal pyramid (regular 3-sided pyramid) with bond angles of 107°. In contrast, boron trifluoride is flat, adopting a trigonal planar geometry because the boron does not have a lone pair of electrons. In ammonia the trigonal pyramid undergoes rapid nitrogen inversion. | 0 | Theoretical and Fundamental Chemistry |
Any nucleus with more than one unpaired nuclear particle (protons or neutrons) will have a charge distribution which results in an electric quadrupole moment. Allowed nuclear energy levels are shifted unequally due to the interaction of the nuclear charge with an electric field gradient supplied by the non-uniform distribution of electron density (e.g. from bonding electrons) and/or surrounding ions. As in the case of NMR, irradiation of the nucleus with a burst of RF electromagnetic radiation may result in absorption of some energy by the nucleus which can be viewed as a perturbation of the quadrupole energy level. Unlike the NMR case, NQR absorption takes place in the absence of an external magnetic field. Application of an external static field to a quadrupolar nucleus splits the quadrupole levels by the energy predicted from the Zeeman interaction. The technique is very sensitive to the nature and symmetry of the bonding around the nucleus. It can characterize phase transitions in solids when performed at varying temperature. Due to symmetry, the shifts become averaged to zero in the liquid phase, so NQR spectra can only be measured for solids. | 0 | Theoretical and Fundamental Chemistry |
Fluid–structure interaction problems and multiphysics problems in general are often too complex to solve analytically and so they have to be analyzed by means of experiments or numerical simulation. Research in the fields of computational fluid dynamics and computational structural dynamics is still ongoing but the maturity of these fields enables numerical simulation of fluid-structure interaction. Two main approaches exist for the simulation of fluid–structure interaction problems:
*Monolithic approach: the equations governing the flow and the displacement of the structure are solved simultaneously, with a single solver
*Partitioned approach: the equations governing the flow and the displacement of the structure are solved separately, with two distinct solvers
The monolithic approach requires a code developed for this particular combination of physical problems whereas the partitioned approach preserves software modularity because an existing flow solver and structural solver are coupled. Moreover, the partitioned approach facilitates solution of the flow equations and the structural equations with different, possibly more efficient techniques which have been developed specifically for either flow equations or structural equations. On the other hand, development of stable and accurate coupling algorithm is required in partitioned simulations. In conclusion, the partitioned approach allows reusing existing software which is an attractive advantage. However, stability of the coupling method needs to be taken into consideration. This is especially difficult, if the mass of the moving structure is small in comparison to the mass of fluid which is displaced by the structure movement.
In addition, the treatment of meshes introduces other classifications of FSI analysis. For example，one can classify them as the conforming mesh methods and the non-conforming mesh methods. Other classifications can be mesh-based methods and meshless methods. | 1 | Applied and Interdisciplinary Chemistry |
Vitamins occur in a variety of related forms known as vitamers. The vitamers of a given vitamin perform the functions of that vitamin and prevent symptoms of deficiency of that vitamin. Vitamins are those essential organic molecules that are not classified as amino acids or fatty acids. They commonly function as enzymatic cofactors, metabolic regulators or antioxidants. Humans require thirteen vitamins in their diet, most of which are actually groups of related molecules (e.g. vitamin E includes tocopherols and tocotrienols): vitamins A, C, D, E, K, thiamine (B), riboflavin (B), niacin (B), pantothenic acid (B), pyridoxine (B), biotin (B), folate (B), and cobalamin (B). The requirement for vitamin D is conditional, as people who get sufficient exposure to ultraviolet light, either from the sun or an artificial source, synthesize vitamin D in the skin. | 0 | Theoretical and Fundamental Chemistry |
ASTM method D4007 or API Manual of Petroleum Measurement Standards chapter 10.4 are commonly used to measure BS&W. These methods both consist of mixing equal volumes of solvent and crude oil then centrifuging in order to separate any solids, free water, or suspended particles.
More precise methods beyond BS&W are available to independently measure water or solids present in
a sample of crude oil. | 1 | Applied and Interdisciplinary Chemistry |
Another use of methylene blue is to treat ifosfamide neurotoxicity. Methylene blue was first reported for treatment and prophylaxis of ifosfamide neuropsychiatric toxicity in 1994. A toxic metabolite of ifosfamide, chloroacetaldehyde (CAA), disrupts the mitochondrial respiratory chain, leading to an accumulation of nicotinamide adenine dinucleotide hydrogen (NADH). Methylene blue acts as an alternative electron acceptor, and reverses the NADH inhibition of hepatic gluconeogenesis while also inhibiting the transformation of chloroethylamine into chloroacetaldehyde, and inhibits multiple amine oxidase activities, preventing the formation of CAA. The dosing of methylene blue for treatment of ifosfamide neurotoxicity varies, depending upon its use simultaneously as an adjuvant in ifosfamide infusion, versus its use to reverse psychiatric symptoms that manifest after completion of an ifosfamide infusion. Reports suggest that methylene blue up to six doses a day have resulted in improvement of symptoms within 10 minutes to several days. Alternatively, it has been suggested that intravenous methylene blue every six hours for prophylaxis during ifosfamide treatment in people with history of ifosfamide neuropsychiatric toxicity. Prophylactic administration of methylene blue the day before initiation of ifosfamide, and three times daily during ifosfamide chemotherapy has been recommended to lower the occurrence of ifosfamide neurotoxicity. | 0 | Theoretical and Fundamental Chemistry |
Liu was born on 17 March 1931 in Changzhou, Jiangsu Province. After graduating from Changzhou Senior High School, he studied at the Department of Chemistry of East China Normal University in Shanghai, and earned his bachelor's degree in 1953. He was assigned to Beijing Normal University, where he worked and studied under Hu Zhibin (). In 1958, he was transferred to the Institute of Nuclear Energy of the Chinese Academy of Sciences to study nuclear chemistry under Feng Xizhang (). It was a turning point in his career. | 0 | Theoretical and Fundamental Chemistry |
The penetration of the IVF market in India is quite low, with only 2,800 cycles per million infertile people in the reproductive age group (20–44 years), as compared to China, which has 6,500 cycles. The key challenges are lack of awareness, affordability and accessibility. Since 2018, however, India has become a destination for fertility tourism, because of lower costs than in the Western world. In December 2021, the Lok Sabha passed the Assisted Reproductive Technology (Regulation) Bill 2020, to regulate ART services including IVF centres, sperm and egg banks. | 1 | Applied and Interdisciplinary Chemistry |
reacts with metal complexes. The cage remains intact in some cases but in other cases, it is degraded. reacts with Vaska's complex ( in an oxidative addition reaction to form a six coordinate iridium complex where the binds through two sulfur atoms and one nitrogen atom. | 0 | Theoretical and Fundamental Chemistry |
It was in 1993 that the Army Corps of Engineers analyzed the system. They determined that an ideal situation would be to "get the water right". In doing so there would be a better flow through the Everglades and a reduced number of canals and levees sending water to tide. | 1 | Applied and Interdisciplinary Chemistry |
The raw materials mixture for glass melting is termed "batch". The batch must be measured properly to achieve a given, desired glass formulation. This batch calculation is based on the common linear regression equation:
with N and N being the molarities 1-column matrices of the batch and glass components respectively, and B being the batching matrix. The symbol "" stands for the matrix transpose operation, "" indicates matrix inversion, and the sign "·" means the scalar product. From the molarities matrices N, percentages by weight (wt%) can easily be derived using the appropriate molar masses. | 0 | Theoretical and Fundamental Chemistry |
The crystal unit of the solid hexahydrate •6 contains the neutral molecule trans- and two molecules of water of crystallization. This species dissolves readily in water and alcohol.
The anhydrous salt is hygroscopic and the hexahydrate is deliquescent. The dihydrate, CoCl(HO), is a coordination polymer. Each Co center is coordinated to four doubly bridging chloride ligands. The octahedron is completed by a pair of mutually trans aquo ligands. | 0 | Theoretical and Fundamental Chemistry |
Prognostic biomarkers give intervention-independent information on disease status and outcome prediction. Prognostic biomarkers can signify individuals in the latent period of a diseases natural history, allowing optimal therapy and prevention until the diseases termination. Prognostic biomarkers give information on disease status by measuring the internal precursors that increase or decrease the likelihood of attaining a disease. For example, blood pressure and cholesterol are biomarkers for CVD. Prognostic biomarkers can be direct or indirect to the causal pathway of a disease. If a prognostic biomarker is a direct step in the causal pathway, it is one of the factors or products of the disease. A prognostic biomarker could be indirectly associated with a disease if it is related to a change caused by the exposure, or related to an unknown factor connected with the exposure or disease. | 1 | Applied and Interdisciplinary Chemistry |
The normal self-similar solution is also referred to as a self-similar solution of the first kind, since another type of self-similar exists for finite-sized problems, which cannot be derived from dimensional analysis, known as a self-similar solution of the second kind. | 1 | Applied and Interdisciplinary Chemistry |
The metals of groups 8 and 9 feature the most extensive library of reactivity with yellow arsenic documented in the scientific literature, with particular focus on reactions of iron and cobalt complexes with As. Much like the chromium and molybdenum sandwich complexes, (CpFe(CO)] complexes of iron react with yellow arsenic to produce analogous bimetallic products featuring "triple-decker" geometry. These reports also detail the isolation of a key intermediate, pentaarsaferrocene ([CpFe(μ-As)]). This intermediate, isolobal to ferrocene, replaces one of the cyclopentadienyl ligands with a cyclic As ligand that features As-As bond lengths of 2.312 Å (in line with delocalized As-As double bonds). This "sandwich-forming" reactivity can be meaningfully tuned by introducing bulkier ligands. Modifying the cyclopentadienyl groups with much bulkier derivatives produces a vastly different set of products. First, a butterfly complex with a central As unit is formed. Irradiation with light leads to further CO elimination and the formation of a bridged butterfly complex, which then rearranges into a unique complex featuring a central As moiety. This ligand, formally tetraanionic, forms an eight-membered ring bridging four iron atoms in total.
Much of the same reactivity, including formation of butterfly and sandwich compounds, has been described for cobalt complexes in the presence of yellow arsenic. Beyond these compounds, the history of reactivity of cobalt and yellow arsenic dates back to 1978, when Sacconi and coworkers reported the reaction of cobalt tetrafluoroborate and yellow arsenic in the presence of 1,1,1-tris(diphenylphosphinomethyl)ethane. The resulting complex features a cyclic As moiety bridging two cobalt centers, of which the former is assigned formally as a 3π-electron system. The reaction of [Cp*Co(CO)] dimer with yellow arsenic was shown by Scherer et al. to produce a wide variety of isolable products, featuring a mixture of linking arsenic moieties including cyclobutane-like and butterfly type complexes. Analogous reactions with rhodium complexes are also known. | 0 | Theoretical and Fundamental Chemistry |
In the context of gene regulation: transactivation is the increased rate of gene expression triggered either by biological processes or by artificial means, through the expression of an intermediate transactivator protein.
In the context of receptor signaling, transactivation occurs when one or more receptors activate yet another; receptor transactivation may result from the crosstalk of signaling cascades or the activation of G protein–coupled receptor hetero-oligomer subunits, among other mechanisms. | 1 | Applied and Interdisciplinary Chemistry |
Early TPV work focused on the use of silicon. Silicon's commercial availability, low cost, scalability and ease of manufacture makes this material an appealing candidate. However, the relatively wide bandgap of Si (1.1eV) is not ideal for use with a black body emitter at lower operating temperatures. Calculations indicate that Si PVs are only feasible at temperatures much higher than 2000 K. No emitter has been demonstrated that can operate at these temperatures. These engineering difficulties led to the pursuit of lower-bandgap semiconductor PVs.
Using selective radiators with Si PVs is still a possibility. Selective radiators would eliminate high and low energy photons, reducing heat generated. Ideally, selective radiators would emit no radiation beyond the band edge of the PV converter, increasing conversion efficiency significantly. No efficient TPVs have been realized using Si PVs. | 0 | Theoretical and Fundamental Chemistry |
The formal journal of the IChemE was the “Transactions” which was initially an annual publication. In order to keep members informed a “Quarterly Bulletin- Institution of Chemical Engineers” was issued. When the Transactions became quarterly, the Bulletin was issued as a supplement. In 1956 both changed to bi-monthly and the title was changed to “The Chemical Engineer” with the sub-title “Bulletin of the Institution of Chemical Engineers". It kept the same numbering, so was issue 125. According to the editorial it would contain news and “articles and comments by members, handled less formally than in Transactions, relating both to practical matters arising from experience and to broader aspects of professional life.”
From 2002 it was published as “TCE” but reverted to its original title with issue 894 in December 2015. | 1 | Applied and Interdisciplinary Chemistry |
Kai Simons honours and awards include:
* 1975 Federation of European Biochemical Society Anniversary Prize
* 1984 Honorary Professor, University of Heidelberg, Germany
* 1989 Lamport Visiting Professor (Columbia, New York)
* 1990 Histochemical Society Lecture
* 1990 Keith R. Porter Lecture, American Society of Cell Biology
* 1991 Anders Jahre Prize for Medical Research
* 1991 NICHD Lectureship in Cell Biology
* 1993 Carl Zeiss Lecture, German Society for Cell Biology
* 1994 Harvey Society Lecture
* 1996 Dunham Lecturer, Harvard University
* 1996 Foreign Member of the American Academy of Arts and Sciences
* 1997 Academia Europaea
* 1997 Adam Neville Lecture, University of Dundee, UK
* 1997 Foreign Member of the National Academy of Sciences, USA
* 1997 Runeberg Prize, Finland
* 1998 Academy of Sciences Leopoldina
* 1998 Choh Hao Li Memorial Lecture in Biochemical Endocrinology, University of California, Berkeley
* 1999 Doctor Honoris Causa, University of Oulu, Finland
* 2000 President of the European Life Scientist Organisation
* 2001 Honorary member of the German Society for Cell Biology
* 2001 ISI Highly cited researcher
* 2001 Schleiden Medal of Academy Leopoldina
* 2002 Hoppe-Seyler Lecture, Society of Biology and Molecular Biology Germany
* 2003 Albert Wander Prize, University of Bern, Switzerland
* 2003 Matti Äyräpää Prize, Finland
* 2003 Doctor Honoris Causa, University of Leuven, Belgium
* 2003 Honorary Professor at TU Dresden
* 2003 Prix Mondial Nessim Habif, University of Geneva, Switzerland
* 2004 Virchow Lecture and Medal, University of Würzburg, Germany
* 2005 Foundation Day Lecture, Centre for Cellular and Molecular Biology, Hyderabad, India
* 2005 van Deenen Medal, Utrecht, The Netherlands
* 2006 A.I. Virtanen Medal, Finland
* 2006 Honorary member of the Societas Biochemica, Biophysica et Microbiologica Fenniae
* 2007 Order of Merit of the Free State of Saxony
* 2010 Doctor honoris causa, University of Kuopio, Finland
* 2011 Doctor honoris causa, University of Geneva, Switzerland
* 2016 Robert Koch Medal
Kai Simons was and is also a member of numerous societies, committees and organisations, as well as an editor for several scientific journals. | 1 | Applied and Interdisciplinary Chemistry |
Interstitials modify the physical and chemical properties of materials.
* Interstitial carbon atoms have a crucial role for the properties and processing of steels, in particular carbon steels.
* Impurity interstitials can be used e.g. for storage of hydrogen in metals.
* The crystal lattice can expand with the concentration of impurity interstitials
* The amorphization of semiconductors such as silicon during ion irradiation is often explained by the build up of a high concentration of interstitials leading eventually to the collapse of the lattice as it becomes unstable.
* Creation of large amounts of interstitials in a solid can lead to a significant energy buildup, which on release can even lead to severe accidents in certain old types of nuclear reactors (Wigner effect). The high-energy states can be released by annealing.
* At least in fcc lattice, interstitials have a large diaelastic softening effect on the material.
* It has been proposed that interstitials are related to the onset of melting and the glass transition. | 1 | Applied and Interdisciplinary Chemistry |
Amphetamine and its enantiomers have been identified as potent full agonists of trace amine-associated receptor 1 (TAAR1), a GPCR, discovered in 2001, that is important for regulation of monoaminergic systems in the brain. Activation of TAAR1 increases cAMP production via adenylyl cyclase activation and inhibits the function of the dopamine transporter, norepinephrine transporter, and serotonin transporter, as well as inducing the release of these monoamine neurotransmitters (effluxion). Amphetamine enantiomers are also substrates for a specific neuronal synaptic vesicle uptake transporter called VMAT2. When amphetamine is taken up by VMAT2, the vesicle releases (effluxes) dopamine, norepinephrine, and serotonin, among other monoamines, into the cytosol in exchange.
Dextroamphetamine (the dextrorotary enantiomer) and levoamphetamine (the levorotary enantiomer) have identical pharmacodynamics, but their binding affinities to their biomolecular targets vary. Dextroamphetamine is a more potent agonist of TAAR1 than levoamphetamine. Consequently, dextroamphetamine produces roughly three to four times more central nervous system (CNS) stimulation than levoamphetamine; however, levoamphetamine has slightly greater cardiovascular and peripheral effects. | 0 | Theoretical and Fundamental Chemistry |
Complexes containing CS are known but uncommon. The rarity of such complexes is partly attributable to the fact that the obvious source material, carbon monosulfide, is unstable. Thus, the synthesis of thiocarbonyl complexes requires indirect routes, such as the reaction of disodium tetracarbonylferrate with thiophosgene:
:NaFe(CO) + CSCl → Fe(CO)CS + 2 NaCl
Complexes of CSe and CTe have been characterized. | 0 | Theoretical and Fundamental Chemistry |
Coarse bubble diffusers produce 1/4 to 1/2 inch (6.4 to 13 mm) bubbles which rise rapidly from the floor of a wastewater treatment plant or sewage treatment plant tank. They are typically used in grit chambers, equalization basins, chlorine contact tanks, and aerobic digesters, and sometimes also in aeration tanks. Generally they are better at vertically "pumping" water than at mass transfer of oxygen. Coarse bubble diffusers typically provide half the mass transfer of oxygen as compared to fine bubble diffusers, given the same air volume. | 1 | Applied and Interdisciplinary Chemistry |
Selenium also plays a role in the functioning of the thyroid gland. It participates as a cofactor for the three thyroid hormone deiodinases. These enzymes activate and then deactivate various thyroid hormones and their metabolites. It may inhibit Hashimotos disease, an auto-immune disease in which the bodys own thyroid cells are attacked by the immune system. A reduction of 21% on TPO antibodies was reported with the dietary intake of 0.2 mg of selenium. | 1 | Applied and Interdisciplinary Chemistry |
Cold spraying (or gas dynamic cold spraying) was introduced to the market in the 1990s. The method was originally developed in the Soviet Union – while experimenting with the erosion of the target, which was exposed to a two-phase high-velocity flow of fine powder in a wind tunnel, scientists observed accidental rapid formation of coatings.
In cold spraying, particles are accelerated to very high speeds by the carrier gas forced through a converging–diverging de Laval type nozzle. Upon impact, solid particles with sufficient kinetic energy deform plastically and bond mechanically to the substrate to form a coating. The critical velocity needed to form bonding depends on the material's properties, powder size and temperature. Metals, polymers, ceramics, composite materials and nanocrystalline powders can be deposited using cold spraying.
Soft metals such as Cu and Al are best suited for cold spraying, but coating of other materials (W, Ta, Ti, MCrAlY, WC–Co, etc.) by cold spraying has been reported.
The deposition efficiency is typically low for alloy powders, and the window of process parameters and suitable powder sizes is narrow. To accelerate powders to higher velocity, finer powders (<20 micrometers) are used. It is possible to accelerate powder particles to much higher velocity using a processing gas having high speed of sound (helium instead of nitrogen).
However, helium is costly and its flow rate, and thus consumption, is higher. To improve acceleration capability, nitrogen gas is heated up to about 900 °C. As a result, deposition efficiency and tensile strength of deposits increase. | 1 | Applied and Interdisciplinary Chemistry |
A codon table can be used to translate a genetic code into a sequence of amino acids. The standard genetic code is traditionally represented as an RNA codon table, because when proteins are made in a cell by ribosomes, it is messenger RNA (mRNA) that directs protein synthesis. The mRNA sequence is determined by the sequence of genomic DNA. In this context, the standard genetic code is referred to as translation table 1. It can also be represented in a DNA codon table. The DNA codons in such tables occur on the sense DNA strand and are arranged in a 5-to-3 direction. Different tables with alternate codons are used depending on the source of the genetic code, such as from a cell nucleus, mitochondrion, plastid, or hydrogenosome.
There are 64 different codons in the genetic code and the below tables; most specify an amino acid. Three sequences, UAG, UGA, and UAA, known as stop codons, do not code for an amino acid but instead signal the release of the nascent polypeptide from the ribosome. In the standard code, the sequence AUG—read as methionine—can serve as a start codon and, along with sequences such as an initiation factor, initiates translation. In rare instances, start codons in the standard code may also include GUG or UUG; these codons normally represent valine and leucine, respectively, but as start codons they are translated as methionine or formylmethionine.
The first table—the standard table—can be used to translate nucleotide triplets into the corresponding amino acid or appropriate signal if it is a start or stop codon. The second table, appropriately called the inverse, does the opposite: it can be used to deduce a possible triplet code if the amino acid is known. As multiple codons can code for the same amino acid, the International Union of Pure and Applied Chemistry's (IUPAC) nucleic acid notation is given in some instances. | 1 | Applied and Interdisciplinary Chemistry |
The continuity and the (potential flow) momentum equations for unsteady flows are given by
The first integral of the (potential flow) momentum equation is given by
where is an arbitrary function. Without loss of generality, we can set since is not uniquely defined. Combining these equations, we obtain
Substituting here results in
Nearly parallel flows: As in before, for nearly parallel flows, we can write (after introudcing a recaled time )
provided the constant Mach number is not close to unity. When is small (transonic flow), we have the following nonlinear equation
Sound waves: In sound waves, the velocity magntiude (or the Mach number) is very small, although the unsteady term is now comparable to the other leading terms in the equation. Thus neglecting all quadratic and higher-order terms and noting that in the same approximation, is a constant (for example, in polytropic gas ), we have
which is a linear wave equation for the velocity potential . Again the oscillatory part of the velocity vector is related to the velocity potential by , while as before is the Laplace operator, and is the average speed of sound in the homogeneous medium. Note that also the oscillatory parts of the pressure and density each individually satisfy the wave equation, in this approximation. | 1 | Applied and Interdisciplinary Chemistry |
In 2009, Illumina released its first whole genome sequencers that were approved for clinical as opposed to research-only use and doctors at academic medical centers began quietly using them to try to diagnose what was wrong with people whom standard approaches had failed to help. In 2009, a team from Stanford led by Euan Ashley performed clinical interpretation of a full human genome, that of bioengineer Stephen Quake. In 2010, Ashley's team reported whole genome molecular autopsy and in 2011, extended the interpretation framework to a fully sequenced family, the West family, who were the first family to be sequenced on the Illumina platform. The price to sequence a genome at that time was $19,500USD, which was billed to the patient but usually paid for out of a research grant; one person at that time had applied for reimbursement from their insurance company. For example, one child had needed around 100 surgeries by the time he was three years old, and his doctor turned to whole genome sequencing to determine the problem; it took a team of around 30 people that included 12 bioinformatics experts, three sequencing technicians, five physicians, two genetic counsellors and two ethicists to identify a rare mutation in the XIAP that was causing widespread problems.
Due to recent cost reductions (see above) whole genome sequencing has become a realistic application in DNA diagnostics. In 2013, the 3Gb-TEST consortium obtained funding from the European Union to prepare the health care system for these innovations in DNA diagnostics. Quality assessment schemes, Health technology assessment and guidelines have to be in place. The 3Gb-TEST consortium has identified the analysis and interpretation of sequence data as the most complicated step in the diagnostic process. At the Consortium meeting in Athens in September 2014, the Consortium coined the word genotranslation for this crucial step. This step leads to a so-called genoreport. Guidelines are needed to determine the required content of these reports.
Genomes2People (G2P), an initiative of Brigham and Womens Hospital and Harvard Medical School was created in 2011 to examine the integration of genomic sequencing into clinical care of adults and children. G2Ps director, Robert C. Green, had previously led the REVEAL study — Risk EValuation and Education for Alzheimers Disease – a series of clinical trials exploring patient reactions to the knowledge of their genetic risk for Alzheimers.
In 2018, researchers at Rady Childrens Hospital Institute for Genomic Medicine in San Diego determined that rapid whole-genome sequencing (rWGS) could diagnose genetic disorders in time to change acute medical or surgical management (clinical utility) and improve outcomes in acutely ill infants. In a retrospective cohort study of acutely ill inpatient infants in a regional childrens hospital from July 2016-March 2017, forty-two families received rWGS for etiologic diagnosis of genetic disorders. The diagnostic sensitivity of rWGS was 43% (eighteen of 42 infants) and 10% (four of 42 infants) for standard genetic tests (P = .0005). The rate of clinical utility of rWGS (31%, thirteen of 42 infants) was significantly greater than for standard genetic tests (2%, one of 42; P = .0015). Eleven (26%) infants with diagnostic rWGS avoided morbidity, one had a 43% reduction in likelihood of mortality, and one started palliative care. In six of the eleven infants, the changes in management reduced inpatient cost by $800,000-$2,000,000. The findings replicated a prior study of the clinical utility of rWGS in acutely ill inpatient infants, and demonstrated improved outcomes, net healthcare savings and consideration as a first tier test in this setting.
A 2018 review of 36 publications found the cost for whole genome sequencing to range from $1,906USD to $24,810USD and have a wide variance in diagnostic yield from 17% to 73% depending on patient groups. | 1 | Applied and Interdisciplinary Chemistry |
Bryostatins are a group of macrolide lactones from (bacterial symbionts of) the marine organism Bugula neritina that were first collected and provided to JL Hartwell’s anticancer drug discovery group at the National Cancer Institute (NCI) by Jack Rudloe. Bryostatins are potent modulators of protein kinase C. They have been studied in clinical trials as anti-cancer agents, as anti-AIDS/HIV agents and in people with Alzheimer's disease. | 0 | Theoretical and Fundamental Chemistry |
The magnetic nanoparticles are typically made from iron oxide, which is fully biodegradable, using methods such as coprecipitation or microemulsion.
The nanoparticles are then combined with gene vectors (DNA, siRNA, ODN, virus, etc.). One method involves linking viral particles to magnetic particles using an avidin-biotin interaction. Viruses can also bind to the nanoparticles via hydrophobic interaction.
Another synthesis method involves coating magnetic nanoparticles with cationic lipids or polymers via salt-induced aggregation. For example, nanoparticles may be conjugated with the polyethylenimine (PEI), a positively charged polymer used commonly as a transfection agent. The PEI solution must have a high pH during synthesis to encourage high gene expression. The positively charged nanoparticles can then associate with negatively charged nucleic acids via electrostatic interaction. | 1 | Applied and Interdisciplinary Chemistry |
Wind tunnels use an inviscid flow of air to test the aerodynamics of an object. Flow straighteners, which consist of many parallel ducts which limit turbulence, are used to produce inviscid flow. Entrance length must be considered in the design of wind tunnels, because the object being tested must be located in the irrotational flow region, between the flow straighteners and the entrance length. | 1 | Applied and Interdisciplinary Chemistry |
Sternhell was a Fellow, of the Australian Academy of Science and of the Royal Australian Chemical Institute. In 2001, he was awarded the Centenary Medal for his service to Australian society and science in organic chemistry and molecular engineering. In June 2018, he was made an Officer of the Order of Australia "for distinguished service to education in the field of organic chemistry, specifically to nuclear magnetic resonance, as an academic and researcher, and to scientific institutions." | 0 | Theoretical and Fundamental Chemistry |
Jones was born in New London, Maryland in a farming family and went to study chemistry at Johns Hopkins University, receiving a PhD in 1892 with studies under Harmon N. Morse. He then travelled to Europe where he worked for two years at the laboratories of Wilhelm Ostwald in Leipzig, Svante Arrhenius in Stockholm and Jacobus vant Hoff in Amsterdam. He then joined Johns Hopkins as a fellow and from 1895 as n instructor. He became a full professor in 1903. He published several books and many papers and was a popular teacher who would recount anecdotes from the lives of chemists he had worked with in Europe. At the time of his death, he was writing a book on the Nature of Solution'. This was published posthumously with a biographical note by his colleague E. Emmet Reid. Jones was depressed and committed suicide by consuming a cyanide pill.
Jones married Harriet Brooks in 1902. | 0 | Theoretical and Fundamental Chemistry |
As listed by ECS:
* 1994 Hubert A. Gasteiger
* 1988 Jennifer A. Bardwell
* 1987 Joachim Maier
* 1975 Larry R. Faulkner
* 1971 M. Stanley Whittingham
* 1966 John Newman
* 1960 A. C. Makrides
* 1953 Jack Halpern
* 1948 Michael Streicher
* 1941 Edward Adler
* 1938 Nathaniel B. Nichols
* 1929 William C. Gardiner | 0 | Theoretical and Fundamental Chemistry |
Corrosion engineering groups have formed around the world to educate, prevent, slow, and manage corrosion. These include the National Association of Corrosion Engineers (NACE), the European Federation of Corrosion (EFC), The Institute of Corrosion in the UK and the Australasian Corrosion Association. The corrosion engineer's main task is to economically and safely manage the effects of corrosion of materials. | 1 | Applied and Interdisciplinary Chemistry |
The most commonly applied methods are MS and HPLC, in which the glycan part is cleaved either enzymatically or chemically from the target and subjected to analysis. In case of glycolipids, they can be analyzed directly without separation of the lipid component.
N-glycans from glycoproteins are analyzed routinely by high-performance-liquid-chromatography (reversed phase, normal phase and ion exchange HPLC) after tagging the reducing end of the sugars with a fluorescent compound (reductive labeling).
A large variety of different labels were introduced in the recent years, where 2-aminobenzamide (AB), anthranilic acid (AA), 2-aminopyridin (PA), 2-aminoacridone (AMAC) and 3-(acetylamino)-6-aminoacridine (AA-Ac) are just a few of them.
O-glycans are usually analysed without any tags, due to the chemical release conditions preventing them to be labeled.
Fractionated glycans from high-performance liquid chromatography (HPLC) instruments can be further analyzed by MALDI-TOF-MS(MS) to get further information about structure and purity. Sometimes glycan pools are analyzed directly by mass spectrometry without prefractionation, although a discrimination between isobaric glycan structures is more challenging or even not always possible. Anyway, direct MALDI-TOF-MS analysis can lead to a fast and straightforward illustration of the glycan pool.
In recent years, high performance liquid chromatography online coupled to mass spectrometry became very popular. By choosing porous graphitic carbon as a stationary phase for liquid chromatography, even non derivatized glycans can be analyzed. Electrospray ionisation (ESI) is frequently used for this application. | 0 | Theoretical and Fundamental Chemistry |
Large-scale oceanic circulation has a direct impact on opal deposition. The Pacific (characterized by nutrient poor surface waters, and deep nutrient rich waters) and Atlantic Ocean circulations favor the production/preservation of silica and carbonate respectively. For instance, Si/N and Si/P ratios increase from the Atlantic to the Pacific and Southern Ocean, favoring opal versus carbonate producers. Consequently, the modern configuration of large-scale oceanic circulation resulted in the localization of major opal burial zones in the Equatorial Pacific, in the eastern boundary current upwelling systems, and by far the most important, the Southern Ocean. | 1 | Applied and Interdisciplinary Chemistry |
The addition of a substituent to a homoaromatic compound has a large influence over the stability of the compound. Depending on the relative locations of the substituent and the homoconjugate linkage, the substituent can either have a stabilizing or destabilizing effect. This interaction is best demonstrated by looking at a substituted tropenylium cation. If an inductively electron-donating group is attached to the cation at the 1st or 3rd carbon position, it has a stabilizing effect, improving the homoaromatic character of the compound. However, if this same substituent is attached at the 2nd or 4th carbon, the interaction between the substituent at the homoconjugate bridge has a destabilizing effect. Therefore, protonation of methyl or phenyl substituted cyclooctatetraenes will result in the 1 isomer of the homotropenylium cation. | 0 | Theoretical and Fundamental Chemistry |
Geological sequestration refers to the storage of CO underground in depleted oil and gas reservoirs, saline formations, or deep, coal beds unsuitable for mining.
Once CO is captured from a point source, such as a cement factory, it can be compressed to ≈100 bar into a supercritical fluid. In this form, the CO could be transported via pipeline to the place of storage. The CO could then be injected deep underground, typically around 1 km, where it would be stable for hundreds to millions of years. Under these storage conditions, the density of supercritical CO is 600 to 800 kg/m.
The important parameters in determining a good site for carbon storage are: rock porosity, rock permeability, absence of faults, and geometry of rock layers. The medium in which the CO is to be stored ideally has a high porosity and permeability, such as sandstone or limestone. Sandstone can have a permeability ranging from 1 to 10 Darcy, with a porosity as high as ≈30%. The porous rock must be capped by a layer of low permeability which acts as a seal, or caprock, for the CO. Shale is an example of a very good caprock, with a permeability of 10 to 10 Darcy. Once injected, the CO plume will rise via buoyant forces, since it is less dense than its surroundings. Once it encounters a caprock, it will spread laterally until it encounters a gap. If there are fault planes near the injection zone, there is a possibility the CO could migrate along the fault to the surface, leaking into the atmosphere, which would be potentially dangerous to life in the surrounding area. Another risk related to carbon sequestration is induced seismicity. If the injection of CO creates pressures underground that are too high, the formation will fracture, potentially causing an earthquake.
Structural trapping is considered the principal storage mechanism, impermeable or low permeability rocks such as mudstone, anhydrite, halite, or tight carbonates act as a barrier to the upward buoyant migration of CO2, resulting in the retention of CO2 within a storage formation. While trapped in a rock formation, CO can be in the supercritical fluid phase or dissolve in groundwater/brine. It can also react with minerals in the geologic formation to become carbonates. | 0 | Theoretical and Fundamental Chemistry |
Supercritical fluids act as a new medium for the generation of novel crystalline forms of APIs (Active Pharmaceutical Ingredients) named as pharmaceutical cocrystals. Supercritical fluid technology offers a new platform that allows a single-step generation of particles that are difficult or even impossible to obtain by traditional techniques. The generation of pure and dried new cocrystals (crystalline molecular complexes comprising the API and one or more conformers in the crystal lattice) can be achieved due to unique properties of SCFs by using different supercritical fluid properties: supercritical CO solvent power, anti-solvent effect and its atomization enhancement. | 0 | Theoretical and Fundamental Chemistry |
The HIV protease is a C2-symmetric homodimeric enzyme consisting of two 99 amino acid monomers. Each monomer contributes an aspartic acid residue that is essential for catalysis, Asp-25 and Asp-25´. The HIV protease has the sequence Asp-Thr-Gly, which is conserved among other mammalian aspartic protease enzymes. An extended beta-sheet region on the monomers, known as the flap, constitutes in part the substrate binding site with the two aspartyl residues lying on the bottom of a hydrophobic cavity. Each flexible flap contains three characteristic regions: side chains that extend outward (Met46, Phe53), hydrophobic chains extending inward (Ile47, Ile54), and a glycine rich region (Gly48, 49, 51, 52). Ile50 remains at the tip of the turn and when the enzyme is unliganded a water molecule makes hydrogen bonds to the backbone of Ile50 on each monomer.
HIV proteases catalyze the hydrolysis of peptide bonds with high sequence selectivity and catalytic proficiency. The mechanism of the HIV protease shares many features with the rest of the aspartic protease family although the full detailed mechanism of this enzyme is not fully understood. The water molecule seems to play a role in the opening and closing of the flaps as well as increasing the affinity between enzyme and substrate. The aspartyl residues are involved in the hydrolysis of the peptide bonds. The preferred cleavage site for this enzyme is the N-terminal side of proline residues, especially between phenylalanine and proline or tyrosine and proline. | 1 | Applied and Interdisciplinary Chemistry |
Quaternary muscle relaxants bind to the nicotinic acetylcholine receptor and inhibit or interfere with the binding and effect of ACh to the receptor. Each ACh-receptor has two receptive sites and activation of the receptor requires binding to both of them. Each receptor site is located at one of the two α-subunits of the receptor. Each receptive site has two subsites, an anionic site that binds to the cationic ammonium head and a site that binds to the blocking agent by donating a hydrogen bond.
Non-depolarizing agents
A decrease in binding of acetylcholine leads to a decrease in its effect and neuron transmission to the muscle is less likely to occur. It is generally accepted that non-depolarizing agents block by acting as reversible competitive inhibitors. That is, they bind to the receptor as antagonists and that leaves fewer receptors available for acetylcholine to bind.
Depolarizing agents
Depolarizing agents produce their block by binding to and activating the ACh receptor, at first causing muscle contraction, then paralysis. They bind to the receptor and cause depolarization by opening channels just like acetylcholine does. This causes repetitive excitation that lasts longer than a normal acetylcholine excitation and is most likely explained by the resistance of depolarizing agents to the enzyme acetylcholinesterase. The constant depolarization and triggering of the receptors keeps the endplate resistant to activation by acetylcholine. Therefore, a normal neuron transmission to muscle cannot cause contraction of the muscle because the endplate is depolarized and thereby the muscle paralysed.
Binding to the nicotinic receptor
Shorter molecules like acetylcholine need two molecules to activate the receptor, one at each receptive site. Decamethonium congeners, which prefer straight line conformations (their lowest energy state), usually span the two receptive sites with one molecule (binding inter-site). Longer congeners must bend when fitting receptive sites.
The greater energy a molecule needs to bend and fit usually results in lower potency. | 1 | Applied and Interdisciplinary Chemistry |
Emulsions are used to manufacture polymer dispersions – polymer production in an emulsion phase has a number of process advantages, including prevention of coagulation of product. Products produced by such polymerisations may be used as the emulsions – products including primary components for glues and paints. Synthetic latexes (rubbers) are also produced by this process. | 0 | Theoretical and Fundamental Chemistry |
Almost all amine oxides are prepared by the oxidation of either tertiary aliphatic amines or aromatic N-heterocycles. Hydrogen peroxide is the most common reagent both industrially and in academia, however peracids are also important. More specialised oxidising agents can see niche use, for instance Caros acid or m'CPBA. Spontaneous or catalysed reactions using molecular oxygen are rare. Certain other reactions will also produce amine oxides, such as the retro-Cope elimination, however they are rarely employed. | 0 | Theoretical and Fundamental Chemistry |
Modifications can also happen in short non-coding RNAs, including small nuclear RNA (snRNA) and microRNA (miRNA). However, these modifications are less common than those in mRNA, tRNA, and rRNA. | 1 | Applied and Interdisciplinary Chemistry |
Cryptococcus neoformans is a basidiomycetous fungus that grows as a budding yeast in culture and in an infected host. C. neoformans causes life-threatening meningoencephalitis in immune compromised patients. It undergoes a filamentous transition during the sexual cycle to produce spores, the suspected infectious agent. The vast majority of environmental and clinical isolates of C. neoformans are mating type α. Filaments ordinarily have haploid nuclei, but these can undergo a process of diploidization (perhaps by endoduplication or stimulated nuclear fusion) to form diploid cells termed blastospores. The diploid nuclei of blastospores can then undergo meiosis, including recombination, to form haploid basidiospores that can then be dispersed. This process is referred to as monokaryotic fruiting. Required for this process is a gene designated dmc1, a conserved homologue of genes RecA in bacteria, and RAD51 in eukaryotes. Dmc1 mediates homologous chromosome pairing during meiosis and repair of double-strand breaks in DNA (see Meiosis; also Michod et al.). Lin et al. suggested that one benefit of meiosis in C. neoformans could be to promote DNA repair in a DNA damaging environment that could include the defensive responses of the infected host. | 1 | Applied and Interdisciplinary Chemistry |
Norman Hackerman (March 2, 1912 – June 16, 2007) was an American chemist, professor, and academic administrator who served as the 18th President of the University of Texas at Austin (1967–1970) and later as the 4th President of Rice University (1970–1985). He was an internationally known expert in metal corrosion. | 0 | Theoretical and Fundamental Chemistry |
Dry basis is an expression of a calculation in chemistry, chemical engineering and related subjects, in which the presence of water (HO) (and/or other solvents) is neglected for the purposes of the calculation. Water (and/or other solvents) is neglected because addition and removal of water (and/or other solvents) are common processing steps, and also happen naturally through evaporation and condensation; it is frequently useful to express compositions on a dry basis to remove these effects.
In food science and pharmacy, dry basis also refers to a ratio of the weight of water to the weight of a completely dry material, as opposed to the wet basis ratio of water to a material under normal conditions that contains a measurable amount of moisture. | 0 | Theoretical and Fundamental Chemistry |
In November 1990, Çeçen joined the faculty at the Boğaziçi University Institute of Environmental Sciences as an instructor. She was promoted to assistant professor in March 1993, associate professor in October 1993, and full professor in June 1999.
Çeçen researches water and wastewater treatment, environmental biotechnology, adsorption processes, and the impacts of hazardous substances on biological treatment. | 1 | Applied and Interdisciplinary Chemistry |
Reductive elimination generally occurs more rapidly from a more sterically hindered metal center because the steric encumbrance is alleviated upon reductive elimination. Additionally, wide ligand bite angles generally accelerate reductive elimination because the sterics force the eliminating groups closer together, which allows for more orbital overlap. | 0 | Theoretical and Fundamental Chemistry |
Studies published beginning in the late 2000s which explore the effect of varying the aspect ratio of the ferromagnetic particles have shown several improvements over conventional MR fluids. Nanowire-based fluids show no sedimentation after qualitative observation over a period of three months. This observation has been attributed to a lower close-packing density due to decreased symmetry of the wires compared to spheres, as well as the structurally supportive nature of a nanowire lattice held together by remnant magnetization. Further, they show a different range of loading of particles (typically measured in either volume or weight fraction) than conventional sphere- or ellipsoid-based fluids. Conventional commercial fluids exhibit a typical loading of 30 to 90 wt%, while nanowire-based fluids show a percolation threshold of ~0.5 wt% (depending on the aspect ratio). They also show a maximum loading of ~35 wt%, since high aspect ratio particles exhibit a larger per particle excluded volume as well as inter-particle tangling as they attempt to rotate end-over-end, resulting in a limit imposed by high off-state apparent viscosity of the fluids. This range of loadings suggest a new set of applications are possible which may have not been possible with conventional sphere-based fluids.
Newer studies have focused on dimorphic magnetorheological fluids, which are conventional sphere-based fluids in which a fraction of the spheres, typically 2 to 8 wt%, are replaced with nanowires. These fluids exhibit a much lower sedimentation rate than conventional fluids, yet exhibit a similar range of loading as conventional commercial fluids, making them also useful in existing high-force applications such as damping. Moreover, they also exhibit an improvement in apparent yield stress of 10% across those amounts of particle substitution.
Another way to increase the performance of magnetorheological fluids is to apply a pressure to them. In particular the properties in term of yield strength can be increased up to ten times in shear mode and up five times in flow mode. The motivation of this behaviour is the increase in the ferromagnetic particles friction, as described by the semiempirical magneto-tribological model by Zhang et al. Even though applying a pressure strongly improves the magnetorheological fluids behaviour, particular attention must be paid in terms of mechanical resistance and chemical compatibility of the sealing system used. | 1 | Applied and Interdisciplinary Chemistry |
Similar to cyclooctane, a cyclodecane ring exhibits several conformations with two lower energy conformations. The boat-chair-boat conformation is energetically minimized, while the chair-chair-chair conformation has significant eclipsing interactions.
These ground-state conformational preferences are useful analogies to more highly functionalized macrocyclic ring systems, where local effects can still be governed to first approximation by energy minimized conformations even though the larger ring size allows more conformational flexibility of the entire structure. For example, in methyl cyclodecane, the ring can be expected to adopt the minimized conformation of boat-chair-boat. The figure below shows the energetic penalty between placing the methyl group at certain sites within the boat-chair-boat structure. Unlike canonical small ring systems, the cyclodecane system with the methyl group placed at the "corners" of the structure exhibits no preference for axial vs. equatorial positioning due to the presence of an unavoidable gauche-butane interaction in both conformations. Significantly more intense interactions develop when the methyl group is placed in the axial position at other sites in the boat-chair-boat conformation. | 0 | Theoretical and Fundamental Chemistry |
The primary modes themselves don't actually lead directly to breakdown, but instead lead to the formation of secondary instability mechanisms. As the primary modes grow and distort the mean flow, they begin to exhibit nonlinearities and linear theory no longer applies. Complicating the matter is the growing distortion of the mean flow, which can lead to inflection points in the velocity profile a situation shown by Lord Rayleigh to indicate absolute instability in a boundary layer. These secondary instabilities lead rapidly to breakdown. These secondary instabilities are often much higher in frequency than their linear precursors. | 1 | Applied and Interdisciplinary Chemistry |
According to Planck, one may think of three main classes of thermodynamic process: natural, fictively reversible, and impossible or unnatural. | 0 | Theoretical and Fundamental Chemistry |
Fine bubble diffusers produce a plethora of very small air bubbles which rise slowly from the floor of a wastewater treatment plant or sewage treatment plant aeration tank and provide substantial and efficient mass transfer of oxygen to the water. The oxygen, combined with the food source, sewage, allows the bacteria to produce enzymes which help break down the waste so that it can settle in the secondary clarifiers or be filtered by membranes. A fine bubble diffuser is commonly manufactured in various forms: tube, disc, plate, and dome. | 1 | Applied and Interdisciplinary Chemistry |
The SECEM factory in Cordoba was located to the west of the city, next to the route of the Cordoba-Seville and Cordoba-Malaga railway lines, which allowed its production to be transported by rail. For this purpose, an industrial branch and several sidings were set up within the industrial complex. Eventually SECEM acquired two 0-2-0T steam locomotives to take over the shunting and traction work with the freight wagons. One of these engines, acquired in 1963, was the former RENFE 020–0212. It is currently preserved and exhibited in Cordoba. | 1 | Applied and Interdisciplinary Chemistry |
Under prebiotic conditions, imidazole-4-acetaldehyde can be synthesized from erythrose, formamidine, formaldehyde, and ammonia. | 1 | Applied and Interdisciplinary Chemistry |
An auxiliary protein unique to most eukaryotes is the E3 binding protein (E3BP), which serves to bind the E3 subunit to the PDC complex. In the case of human E3BP, hydrophobic proline and leucine residues in the BP interact with the surface recognition site formed by the binding of two identical E3 monomers. | 1 | Applied and Interdisciplinary Chemistry |
Fugacity is closely related to the chemical potential . In a pure substance, is equal to the Gibbs energy for a mole of the substance, and
where and are the temperature and pressure, is the volume per mole and is the entropy per mole. | 0 | Theoretical and Fundamental Chemistry |
In 1913 Weeks earned a bachelors degree in chemistry from Ripon College where she worked with Albert F. Gilman. In 1914 she received a masters degree from the University of Wisconsin–Madison where she worked with Joseph Howard Mathews.
For seven years (1914–1921), Weeks worked as a high school teacher and chemical technician. In 1921, she took a job as a college instructor, teaching quantitative analysis at the University of Kansas while continuing to study. She completed her Ph.D. at the University of Kansas in 1927, writing a thesis on the role of hydrogen ion concentration in the precipitation of calcium and magnesium.
Once she had her Ph.D. Weeks became an assistant professor and in 1937, an associate professor. She remained in Kansas for 22 years, carrying a heavy teaching load and doing a limited amount of laboratory research. Her research tended to be in the areas of physical and analytic chemistry. While in Kansas, she began researching and writing about the history of chemistry, and published Discovery of the Elements (1933).
In 1944, Weeks left Kansas to become a research librarian at the Kresge-Hooker Science Library of Wayne State University in Detroit, Michigan. There she became head of the translation department.
Weeks retired from Wayne State in 1954 and continued to live in Detroit. Weeks continued to be active as a translator and as an editor after her retirement, working with the Record of Chemical Progress (?-1971) and Chymia (1956-1967).
Weeks was a member of the American Chemical Society, the American Association for Advancement of Science, the History of Science Society, the Special Libraries Association, the Swedish History of Science Society, Phi Beta Kappa, and Sigma Xi. | 1 | Applied and Interdisciplinary Chemistry |
The number of theoretical plates, or separation efficiency, in capillary electrophoresis is given by:
where is the number of theoretical plates, is the apparent mobility in the separation medium and is the diffusion coefficient of the analyte. According to this equation, the efficiency of separation is only limited by diffusion and is proportional to the strength of the electric field, although practical considerations limit the strength of the electric field to several hundred volts per centimeter. Application of very high potentials (>20-30 kV) may lead to arcing or breakdown of the capillary. Further, application of strong electric fields leads to resistive heating (Joule heating) of the buffer in the capillary. At sufficiently high field strengths, this heating is strong enough that radial temperature gradients can develop within the capillary. Since electrophoretic mobility of ions is generally temperature-dependent (due to both temperature-dependent ionization and solvent viscosity effects), a non-uniform temperature profile results in variation of electrophoretic mobility across the capillary, and a loss of resolution. The onset of significant Joule heating can be determined by constructing an "Ohms Law plot", wherein the current through the capillary is measured as a function of applied potential. At low fields, the current is proportional to the applied potential (Ohms Law), whereas at higher fields the current deviates from the straight line as heating results in decreased resistance of the buffer. The best resolution is typically obtained at the maximum field strength for which Joule heating is insignificant (i.e. near the boundary between the linear and nonlinear regimes of the Ohm's Law plot). Generally capillaries of smaller inner diameter support use of higher field strengths, due to improved heat dissipation and smaller thermal gradients relative to larger capillaries, but with the drawbacks of lower sensitivity in absorbance detection due to shorter path length, and greater difficulty in introducing buffer and sample into the capillary (small capillaries require greater pressure and/or longer times to force fluids through the capillary).
The efficiency of capillary electrophoresis separations is typically much higher than the efficiency of other separation techniques like HPLC. Unlike HPLC, in capillary electrophoresis there is no mass transfer between phases. In addition, the flow profile in EOF-driven systems is flat, rather than the rounded laminar flow profile characteristic of the pressure-driven flow in chromatography columns as shown in figure 5. As a result, EOF does not significantly contribute to band broadening as in pressure-driven chromatography. Capillary electrophoresis separations can have several hundred thousand theoretical plates.
The resolution () of capillary electrophoresis separations can be written as:
According to this equation, maximum resolution is reached when the electrophoretic and electroosmotic mobilities are similar in magnitude and opposite in sign. In addition, it can be seen that high resolution requires lower velocity and, correspondingly, increased analysis time.
Besides diffusion and Joule heating (discussed above), factors that may decrease the resolution in capillary electrophoresis from the theoretical limits in the above equation include, but are not limited to, the finite widths of the injection plug and detection window; interactions between the analyte and the capillary wall; instrumental non-idealities such as a slight difference in height of the fluid reservoirs leading to siphoning; irregularities in the electric field due to, e.g., imperfectly cut capillary ends; depletion of buffering capacity in the reservoirs; and electrodispersion (when an analyte has higher conductivity than the background electrolyte). Identifying and minimizing the numerous sources of band broadening is key to successful method development in capillary electrophoresis, with the objective of approaching as close as possible to the ideal of diffusion-limited resolution. | 0 | Theoretical and Fundamental Chemistry |
An often used approximation of relative permeability is the Corey correlation
which is a power law in saturation. The Corey correlations of the relative permeability for oil and water are then
If the permeability basis is normal oil with irreducible water present, then .
The empirical parameters and are called curve shape parameters or simply shape parameters, and they can be obtained from measured data either by analytical interpretation of measured data, or by optimization using a core flow numerical simulator to match the experiment (often called history matching). is sometimes appropriate. The physical properties and are obtained either before or together with the optimizing of and .
In case of gas-water system or gas-oil system there are Corey correlations similar to the oil-water relative permeabilities correlations shown above. | 1 | Applied and Interdisciplinary Chemistry |
* TUBA Prize of the Turkish Academy of Sciences (2015)
* Wittgenstein-Preis (2012)
* Honorary doctorate awarded by the University of Bucharest in Romania (2012)
* Honorary doctorate awarded by the Åbo Akademi in Finland (2011)
* Kardinal-Innitzer Award (2010)
* Humanity Medal of the City of Linz (2010)
* Austrians of 2008, category Education (ORF and Die Presse)
* Turkish National Science Prize (TUBITAK Bilim Ödülü) 2006
* ENERGY GLOBE Upper Austria 2003, sponsored by the OÖN
* Basic Award 2001 sponsored by the "Open Upper Austria" | 0 | Theoretical and Fundamental Chemistry |
THz radiation has several distinct advantages for use in spectroscopy. Many materials are transparent at terahertz wavelengths, and this radiation is safe for biological tissue being non-ionizing (as opposed to X-rays). Many interesting materials have unique spectral fingerprints in the terahertz range that may be used for identification. Demonstrated examples include several different types of explosives, dynamic fingerprinting of DNA and protein molecules using polarization varying anisotropic terahertz microspectroscopy, polymorphic forms of many compounds used as active pharmaceutical ingredients (API) in commercial medications as well as several illegal narcotic substances.
Since many materials are transparent to THz radiation, underlying materials can be accessed through visually opaque intervening layers.
Though not strictly a spectroscopic technique, the ultrashort width of THz radiation pulses allows for measurements (e.g., thickness, density, defect location) on difficult-to-probe materials like foam. These measurement capabilities share many similarities to those of pulsed ultrasonic systems as the depth of buried structures can be inferred through timing of their reflections of these short terahertz pulses. | 0 | Theoretical and Fundamental Chemistry |
Much of the development of 3D optical data storage has been carried out in universities. The groups that have provided valuable input include:
*Peter T. Rentzepis was the originator of this field, and has recently developed materials free from destructive readout.
*Watt W. Webb codeveloped the two-photon microscope in Bell Labs, and showed 3D recording on photorefractive media.
*Masahiro Irie developed the diarylethene family of photochromic materials.
*Yoshimasa Kawata, Satoshi Kawata, and Zouheir Sekkat have developed and worked on several optical data manipulation systems, in particular involving poled polymer systems.
*Kevin C Belfield is developing photochemical systems for 3D optical data storage by the use of resonance energy transfer between molecules, and also develops high two–photon cross-section materials.
*Seth Marder performed much of the early work developing logical approaches to the molecular design of high two–photon cross-section chromophores.
*Tom Milster has made many contributions to the theory of 3D optical data storage.
*Robert McLeod has examined the use of microholograms for 3D optical data storage.
*Min Gu has examined confocal readout and methods for its enhancement. | 0 | Theoretical and Fundamental Chemistry |
The hardness of local water supplies depends on the source of water. Water in streams flowing over volcanic (igneous) rocks will be soft, while water from boreholes drilled into porous rock is normally very hard. | 0 | Theoretical and Fundamental Chemistry |
# Cholesterol + oxygen --(enzyme cholesterol oxidase)--> cholestenone + hydrogen peroxide
# Hydrogen peroxide + 4-aminophenazone + phenol --(enzyme peroxidase)--> colored complex + water | 0 | Theoretical and Fundamental Chemistry |
When it was discovered that the self-cleaning qualities of ultrahydrophobic surfaces come from physical-chemical properties at the microscopic to nanoscopic scale rather than from the specific chemical properties of the leaf surface, the possibility arose of using this effect in manmade surfaces, by mimicking nature in a general way rather than a specific one.
Some nanotechnologists have developed treatments, coatings, paints, roof tiles, fabrics and other surfaces that can stay dry and clean themselves by replicating in a technical manner the self-cleaning properties of plants, such as the lotus plant. This can usually be achieved using special fluorochemical or silicone treatments on structured surfaces or with compositions containing micro-scale particulates.
In addition to chemical surface treatments, which can be removed over time, metals have been sculpted with femtosecond pulse lasers to produce the lotus effect. The materials are uniformly black at any angle, which combined with the self-cleaning properties might produce very low maintenance solar thermal energy collectors, while the high durability of the metals could be used for self-cleaning latrines to reduce disease transmission.
Further applications have been marketed, such as self-cleaning glasses installed in the sensors of traffic control units on German autobahns developed by a cooperation partner (Ferro GmbH).
The Swiss companies HeiQ and [http://www.schoeller-textiles.com/en.html Schoeller Textil] have developed stain-resistant textiles under the brand names "[https://web.archive.org/web/20160812113734/http://heiq.com/products/eco-dry/ HeiQ Eco Dry]" and "[http://www.schoeller-textiles.com/en/technologies/nanosphere.html nanosphere]" respectively. In October 2005, tests of the Hohenstein Research Institute showed that clothes treated with NanoSphere technology allowed tomato sauce, coffee and red wine to be easily washed away even after a few washes. Another possible application is thus with self-cleaning awnings, tarpaulins and sails, which otherwise quickly become dirty and difficult to clean.
Superhydrophobic coatings applied to microwave antennas can significantly reduce rain fade and the buildup of ice and snow. "Easy to clean" products in ads are often mistaken in the name of the self-cleaning properties of hydrophobic or ultrahydrophobic surfaces. Patterned ultrahydrophobic surfaces also show promise for "lab-on-a-chip" microfluidic devices and can greatly improve surface-based bioanalysis.
Superhydrophobic or hydrophobic properties have been used in dew harvesting, or the funneling of water to a basin for use in irrigation. The Groasis Waterboxx has a lid with a microscopic pyramidal structure based on the ultrahydrophobic properties that funnel condensation and rainwater into a basin for release to a growing plant's roots. | 0 | Theoretical and Fundamental Chemistry |
Although CoQ may be measured in blood plasma, these measurements reflect dietary intake rather than tissue status. Currently, most clinical centers measure CoQ levels in cultured skin fibroblasts, muscle biopsies, and blood mononuclear cells. Culture fibroblasts can be used also to evaluate the rate of endogenous CoQ biosynthesis, by measuring the uptake of C-labeled p-hydroxybenzoate. | 1 | Applied and Interdisciplinary Chemistry |
The term kodecyte is used to describe cells with detectable Function-Spacer-Lipid (FSL) constructs, and in concert, the term kodevirion (pronounced co-da-virion), is used to describe virions with detectable FSL constructs.
The method for labeling virions with FSL constructs is simple, non covalent and only involves incubation of the virion with the FSL construct in saline for a few hours – nothing further is required. The FSL construct will spontaneously, stably and quantitatively incorporate into the virion membrane. Virions have been labelled with fluorescent (FSL-FLRO4) and radioactive iodine (FSL-125I). FSL-FLRO4 could be shown to label virions in a dose dependent manner and could be visualized by flow cytometry either directly, or indirectly if the virion had bound to the cell or fused with the cell membrane. FSLs do not appear to significantly affect the virions infectivity or their ability to bind target cells, probably because they integrate into the membrane without exposing the virion to chemical agents or covalent modification. | 1 | Applied and Interdisciplinary Chemistry |
The first nucleotide to be expanded was the purine adenine. Nelson J. Leonard and colleagues synthesized this original x-nucleotide, which was referred to as "expanded adenine". xA was used as a probe in the investigation of active sites of ATP-dependent enzymes, more specifically what modifications the substrate could take while still being functional. Almost two decades later, the other three bases were successfully expanded and later integrated into a double helix by Eric T. Kool and colleagues. Their goal was to create a synthetic genetic system which mimics and surpasses the functions of the natural genetic system, and to broaden the applications of DNA both in living cells and in experimental biochemistry. Once the expanded base set was created, the goal shifted to identifying or developing faithful replication enzymes and further optimizing the expanded DNA alphabet. | 1 | Applied and Interdisciplinary Chemistry |
A Gilman reagent is a diorganocopper compound with the formula Li[CuR], where R is an alkyl or aryl. They are colorless solids. | 0 | Theoretical and Fundamental Chemistry |
The plot of against has often been called a "Michaelis–Menten plot", even recently, but this is misleading, because Michaelis and Menten did not use such a plot. Instead, they plotted against , which has some advantages over the usual ways of plotting Michaelis–Menten data. It has as dependent variable, and thus does not distort the experimental errors in . Michaelis and Menten did not attempt to estimate directly from the limit approached at high , something difficult to do accurately with data obtained with modern techniques, and almost impossible with their data. Instead they took advantage of the fact that the curve is almost straight in the middle range and has a maximum slope of i.e. . With an accurate value of it was easy to determine from the point on the curve corresponding to .
This plot is virtually never used today for estimating and , but it remains of major interest because it has another valuable property: it allows the properties of isoenzymes catalysing the same reaction, but active in very different ranges of substrate concentration, to be compared on a single plot. For example, the four mammalian isoenzymes of hexokinase are half-saturated by glucose at concentrations ranging from about 0.02 mM for hexokinase A (brain hexokinase) to about 50 mM for hexokinase D ("glucokinase", liver hexokinase), more than a 2000-fold range. It would be impossible to show a kinetic comparison between the four isoenzymes on one of the usual plots, but it is easily done on a semi-logarithmic plot. | 0 | Theoretical and Fundamental Chemistry |
Both bulk and depth analysis of solids may be performed with glow discharge. Bulk analysis assumes that the sample is fairly homogeneous and averages the emission or mass spectrometric signal over time. Depth analysis relies on tracking the signal in time, therefore, is the same as tracking the elemental composition in depth.
Depth analysis requires greater control over operational parameters. For example, conditions (current, potential, pressure) need to be adjusted so that the crater produced by sputtering is flat bottom (that is, so that the depth analyzed over the crater area is uniform). In bulk measurement, a rough or rounded crater bottom would not adversely impact analysis. Under the best conditions, depth resolution in the single nanometer range has been achieved (in fact, within-molecule resolution has been demonstrated).
The chemistry of ions and neutrals in vacuum is called gas phase ion chemistry and is part of the analytical study that includes glow discharge. | 0 | Theoretical and Fundamental Chemistry |
Kinetic Monte Carlo (KMC) is a form of computer simulation in which atoms and molecules are allowed to interact at given rate that could be controlled based on known physics. This simulation method is typically used in the micro-electrical industry to study crystal surface growth, and it can provide accurate models surface morphology in different growth conditions on a time scales typically ranging from micro-seconds to hours. Experimental methods such as scanning electron microscopy (SEM), X-ray diffraction, and transmission electron microscopy (TEM), and other computer simulation methods such as molecular dynamics (MD), and Monte Carlo simulation (MC) are widely used. | 0 | Theoretical and Fundamental Chemistry |
Some anionic nitrito complexes undergo acid-induced deoxygenation to give the nitrosyl complex.
The reaction is reversible in some cases. Thus, one can generate nitrito complexes by base-hydrolysis of electrophilic metal nitrosyls.
Nitro complexes also catalyze the oxidation of alkenes. | 0 | Theoretical and Fundamental Chemistry |
A variety of experimental concerns exist for IMHR reactions. Although most of the common Pd(0) catalysts are commercially available (Pd(PPh), Pd(dba), and derivatives), they may also be prepared by simple, high-yielding procedures. Palladium(II) acetate is cheap and may be reduced in situ to palladium(0) with phosphine. Three equivalents of phosphine per equivalent of palladium acetate are commonly used; these conditions generate Pd(PR) as the active catalyst. Bidentate phosphine ligands are common in asymmetric reactions to enhance stereoselectivity.
A wide variety of bases may be used, and the base is often employed in excess. Potassium carbonate is the most common base employed, and inorganic bases are generally used more often than organic bases. A number of additives have also been identified for the Heck reaction—silver salts may be used to drive the reaction down the cationic pathway, and halide salts may be used to convert aryl triflates via the neutral pathway. Alcohols have been shown to enhance catalyst stability in some cases, and acetate salts are beneficial in reactions following the anionic pathway. | 0 | Theoretical and Fundamental Chemistry |
Gold(III) bromide is a dark-red to black crystalline solid. It has the empirical formula , but exists primarily as a dimer with the molecular formula in which two gold atoms are bridged by two bromine atoms. It is commonly referred to as gold(III) bromide, gold tribromide, and rarely but traditionally auric bromide, and sometimes as digold hexabromide. As is similar with the other gold halides, this compound is unique for being a coordination complex of a group 11 transition metal that is stable in an oxidation state of +3 whereas copper or silver complexes persist in oxidation states of +1 or +2. | 0 | Theoretical and Fundamental Chemistry |
This book deals with assaying techniques. Various designs of furnaces are detailed. Then cupellation, crucibles, scorifiers and muffle furnaces are described. The correct method of preparation of the cupels is covered in detail with beech ashes being preferred. Various other additives and formulae are described, but Agricola does not judge between them. Triangular crucibles and scorifiers are made of fatty clay with a temper of ground-up crucibles or bricks. Agricola then describes in detail which substances should be added as fluxes as well as lead for smelting or assaying. The choice is made by which colour the ore burns out which gives an indication of the metals present. The lead should be silver-free or be assayed separately. The prepared ore is wrapped in paper, placed on a scorifier and then placed under a muffle covered in burning charcoal in the furnace. The cupel should be heated at the same time. The scorifier is removed and the metal transferred to the cupel. Alternatively the ore can be smelted in a triangular crucible, and then have lead mixed with it when it is added to the cupel. The cupel is placed in the furnace and copper is separated into the lead which forms litharge in the cupel leaving the noble metal. Gold and silver are parted using an aqua which is probably nitric acid. Agricola describes precautions for ensuring the amount of lead is correct and also describes the amalgamation of gold with mercury. Assay techniques for base metals such as tin are described as well as techniques for alloys such as silver tin. The use of a touchstone to assay gold and silver is discussed. Finally detailed arithmetical examples show the calculations needed to give the yield from the assay. | 1 | Applied and Interdisciplinary Chemistry |
The EPA has stated that while some companies have reached certain conclusions related to PFASs, the EPA research is still ongoing and as of 2023, remains inconclusive as it relates to the certainty of detrimental effects on humans, according to the EPA: | 0 | Theoretical and Fundamental Chemistry |
DamID is usually performed on around 10,000 cells, (although it has been demonstrated with fewer). This means that the data obtained represents the average binding, or probability of a binding event across that cell population. A DamID protocol for single cells has also been developed and applied to human cells. Single cell approaches can highlight the heterogeneity of chromatin associations between cells. | 1 | Applied and Interdisciplinary Chemistry |
A Pake Doublet (or "Pake Pattern") is a characteristic line shape seen in solid-state nuclear magnetic resonance and electron paramagnetic resonance spectroscopy. It was first described by George Pake.
It arises from dipolar coupling between isolated two spin-1/2 nuclei, or from transitions in quadrupolar nuclei such as deuterium. It is the general shape obtained from an orientationally dependent doublet. The "horns" of the Pake doublet correspond to the situation when the principal axis of the coupling interaction (the internuclear vector in the case dipolar coupling and the principal component of the electric field gradient tensor for quadrupolar nuclei) is perpendicular to the magnetic field. This situation is the most probable and the intensity is much higher. The "feet" of the lineshape correspond to the situation when the principal axis of the coupling interaction is parallel to the magnetic field which is much less statistically relevant.
Pake was the first to describe this lineshape and used it to extract the proton-proton distance from his experiments on a single crystal and powdered hydrates of gypsum (CaSO.2HO). This made it possible to experimentally determine the internuclear distance between the hydrogen atoms in water.
In solids with vacant positions, dipole coupling is averaged partially due to water diffusion which proceeds according to the symmetry of the solids and the probability distribution of molecules between the vacancies. In the case the averaged lineshape is used to analyze crystal symmetry, phase transitions, and the degree of molecular disorder in crystalline hydrates, zeolites, clays and biological tissues. | 0 | Theoretical and Fundamental Chemistry |
The moving-boundary electrophoresis apparatus includes a U-shaped cell filled with buffer solution and electrodes immersed at its ends. The sample applied could be any mixture of charged components such as a protein mixture. On applying voltage, the compounds will migrate to the anode or cathode depending on their charges. The change in the refractive index at the boundary of the separated compounds is detected using schlieren optics at both ends of the solution in the cell. | 0 | Theoretical and Fundamental Chemistry |
Aromatic compounds play key roles in the biochemistry of all living things. The four aromatic amino acids histidine, phenylalanine, tryptophan, and tyrosine each serve as one of the 20 basic building-blocks of proteins. Further, all 5 nucleotides (adenine, thymine, cytosine, guanine, and uracil) that make up the sequence of the genetic code in DNA and RNA are aromatic purines or pyrimidines. The molecule heme contains an aromatic system with 22 π electrons. Chlorophyll also has a similar aromatic system.
Aromatic compounds are important in industry. Key aromatic hydrocarbons of commercial interest are benzene, toluene, ortho-xylene and para-xylene. About 35 million tonnes are produced worldwide every year. They are extracted from complex mixtures obtained by the refining of oil or by distillation of coal tar, and are used to produce a range of important chemicals and polymers, including styrene, phenol, aniline, polyester and nylon. | 0 | Theoretical and Fundamental Chemistry |
In analytical chemistry, argentometry is a type of titration involving the silver(I) ion. Typically, it is used to determine the amount of chloride present in a sample. The sample solution is titrated against a solution of silver nitrate of known concentration. Chloride ions react with silver(I) ions to give the insoluble silver chloride:
: Ag (aq) + Cl (aq) → AgCl (s) (K = 5.88 × 10) | 0 | Theoretical and Fundamental Chemistry |
Like organolithium compounds, Grignard reagents are useful for forming carbon–heteroatom bonds.
Grignard reagents react with many metal-based electrophiles. For example, they undergo transmetallation with cadmium chloride (CdCl) to give dialkylcadmium: | 0 | Theoretical and Fundamental Chemistry |
Silicon wafers are treated with solutions of electronic-grade hydrofluoric acid in water, buffered water, or alcohol. One of the relevant reactions is simply removal of silicon oxides:
:SiO + 4 HF → SiF + 2 HO
The key reaction however is the formation of the hydrosilane functional group.
atomic force microscope (AFM) has been used to manipulate hydrogen-terminated silicon surfaces. | 0 | Theoretical and Fundamental Chemistry |
These density differences caused by temperature and salinity ultimately separate ocean water into distinct water masses, such as the North Atlantic Deep Water (NADW) and Antarctic Bottom Water (AABW). These two waters are the main drivers of the circulation, which was established in 1960 by Henry Stommel and Arnold B. Arons. They have chemical, temperature and isotopic ratio signatures (such as Pa / Th ratios) which can be traced, their flow rate calculated, and their age determined. NADW is formed because North Atlantic is a rare place in the ocean where precipitation, which adds fresh water to the ocean and so reduces its salinity, is outweighed by evaporation, in part due to high windiness. When water evaporates, it leaves salt behind, and so the surface waters of the North Atlantic are particularly salty. North Atlantic is also an already cool region, and evaporative cooling reduces water temperature even further. Thus, this water sinks downwards in the Norwegian Sea, fills the Arctic Ocean Basin and spills southwards through the Greenland-Scotland-Ridge - crevasses in the submarine sills that connect Greenland, Iceland and Great Britain. It cannot flow towards the Pacific Ocean due to the narrow shallows of the Bering Strait, but it does slowly flow into the deep abyssal plains of the south Atlantic.
In the Southern Ocean, strong katabatic winds blowing from the Antarctic continent onto the ice shelves will blow the newly formed sea ice away, opening polynyas in locations such as Weddell and Ross Seas, off the Adélie Coast and by Cape Darnley. Without sea ice acting a Meanwhile, sea ice starts reforming, so the surface waters also get saltier, hence very dense. In fact, the formation of sea ice contributes to an increase in surface seawater salinity; saltier brine is left behind as the sea ice forms around it (pure water preferentially being frozen). Increasing salinity lowers the freezing point of seawater, so cold liquid brine is formed in inclusions within a honeycomb of ice. The brine progressively melts the ice just beneath it, eventually dripping out of the ice matrix and sinking. This process is known as brine rejection. The resulting Antarctic bottom water sinks and flows north and east. It is denser than the NADW, and so flows beneath it. AABW formed in the Weddell Sea will mainly fill the Atlantic and Indian Basins, whereas the AABW formed in the Ross Sea will flow towards the Pacific Ocean. At the Indian Ocean, a vertical exchange of a lower layer of cold and salty water from the Atlantic and the warmer and fresher upper ocean water from the tropical Pacific occurs, in what is known as overturning. In the Pacific Ocean, the rest of the cold and salty water from the Atlantic undergoes haline forcing, and becomes warmer and fresher more quickly.
The out-flowing undersea of cold and salty water makes the sea level of the Atlantic slightly lower than the Pacific and salinity or halinity of water at the Atlantic higher than the Pacific. This generates a large but slow flow of warmer and fresher upper ocean water from the tropical Pacific to the Indian Ocean through the Indonesian Archipelago to replace the cold and salty Antarctic Bottom Water. This is also known as haline forcing (net high latitude freshwater gain and low latitude evaporation). This warmer, fresher water from the Pacific flows up through the South Atlantic to Greenland, where it cools off and undergoes evaporative cooling and sinks to the ocean floor, providing a continuous thermohaline circulation. | 0 | Theoretical and Fundamental Chemistry |
Sulphur powder is sprinkled into a test tube with three millilitres of urine and if the test is positive, the sulphur powder sinks to the bottom of the test tube. Sulphur powder sinks because bile salts decrease the surface tension of urine. | 0 | Theoretical and Fundamental Chemistry |
The double-helix model of DNA structure was first published in the journal Nature by James Watson and Francis Crick in 1953, (X,Y,Z coordinates in 1954) based on the work of Rosalind Franklin and her student Raymond Gosling, who took the crucial X-ray diffraction image of DNA labeled as "Photo 51", and Maurice Wilkins, Alexander Stokes, and Herbert Wilson, and base-pairing chemical and biochemical information by Erwin Chargaff. Before this, Linus Pauling—who had already accurately characterised the conformation of protein secondary structure motifs—and his collaborator Robert Corey had posited, erroneously, that DNA would adopt a triple-stranded conformation.
The realization that the structure of DNA is that of a double-helix elucidated the mechanism of base pairing by which genetic information is stored and copied in living organisms and is widely considered one of the most important scientific discoveries of the 20th century. Crick, Wilkins, and Watson each received one-third of the 1962 Nobel Prize in Physiology or Medicine for their contributions to the discovery. | 0 | Theoretical and Fundamental Chemistry |
Suzuki was born on September 12, 1930, in Mukawa, Hokkaidō, his father died when he was in high school. He studied chemistry at Hokkaido University (Hokudai) and after receiving his PhD while he worked there as assistant professor. He initially wanted to major in mathematics, as his favorite subject in childhood was arithmetic. It was an encounter with two books that became an opportunity to advance to the path of organic synthesis, one is Textbook of Organic Chemistry written by Louis Fieser of Harvard University, and another is Hydroboration written by Herbert C. Brown of Purdue University. | 0 | Theoretical and Fundamental Chemistry |
Orgel proposed a novel solution to a problem with Juan Oro's proposed mechanism of nucleobase synthesis on the early Earth, which relied on the reaction of five molecules of hydrogen cyanide (HCN) to form adenine. The problem with this was that it would require much more concentrated hydrogen cyanide than evidence suggested was present.
Orgel suggested that the hydrogen cyanide was frozen in solution. This would concentrate HCN molecules in the spaces in between the crystal lattice of ice, and also solve the problem of HCN being too volatile in a liquid water solution. | 0 | Theoretical and Fundamental Chemistry |
Gelation of polymers can be described in the framework of the Erdős–Rényi model or the Lushnikov model, which answers the question when a giant component arises. | 0 | Theoretical and Fundamental Chemistry |
The dendrimer is assembled from a multifunctional core, which is extended outward by a series of reactions, commonly a Michael reaction. Each step of the reaction must be driven to full completion to prevent mistakes in the dendrimer, which can cause trailing generations (some branches are shorter than the others). Such impurities can impact the functionality and symmetry of the dendrimer, but are extremely difficult to purify out because the relative size difference between perfect and imperfect dendrimers is very small. | 0 | Theoretical and Fundamental Chemistry |
Another variety of transposons, discovered in 2001, which can also potentially capture host DNA. Helitrons are thought to replicate via a "rolling circle", in which transposase links the helitron to two distinct regions of the genome at once, using a helicase, ligase, and nuclease in the process to unravel the strands involved, replicate the helitron, and subsequently ligate the replicated material into the new site. During this process, it is thought that the helitrons often encode for the surrounding DNA and integrate this into their own material. Non-autuonomous helitrons may lack a transposase, a helicase, a ligase, or a nuclease. All are thought to be necessary for this complex process of transposition. | 1 | Applied and Interdisciplinary Chemistry |
In biochemistry, the KIX domain (kinase-inducible domain (KID) interacting domain) or CREB binding domain is a protein domain of the eukaryotic transcriptional coactivators CBP and P300. It serves as a docking site for the formation of heterodimers between the coactivator and specific transcription factors. Structurally, the KIX domain is a globular domain consisting of three α-helices and two short 3-helices.
The KIX domain was originally discovered in 1996 as the specific and minimal region in CBP that binds and interacts with phosphorylated CREB to activate transcription. It was thus first termed CREB-binding domain. However, when it was later discovered that it also binds many other proteins, the more general name KIX domain became favoured. The KIX domain contains two separate binding sites: the "c-Myb site", named after the oncoprotein c-Myb, and the "MLL site", named after the proto-oncogene MLL (Mixed Lineage Leukemia, KMT2A).
The paralogous coactivators CBP (CREBBP) and P300 (EP300) are recruited to DNA-bound transcription factors to activate transcription. Coactivators can associate with promoters and enhancers in the DNA only indirectly through protein-protein contacts with transcription factors. CBP and P300 activate transcription synergistically in two ways: first, by remodelling and relaxing chromatin through their intrinsic histone acetyltransferase activity, and second, by recruiting the basal transcription machinery, such as RNA polymerase II.
The KIX domain belongs to the proposed GACKIX domain superfamily. GACKIX comprises structurally and functionally highly homologous domains in related proteins. It is named after the protein GAL11 / ARC105 (MED15), the plant protein CBP-like, and the KIX domain from CBP and P300. Additional instances include RECQL5 and related plant proteins. All of these contain a KIX domain or KIX-related domain that interacts with the transactivation domain of many different transcription factors. The distinction between a KIX domain, a KIX-related domain and a GACKIX domain is subject to an ongoing debate and not clearly defined. | 1 | Applied and Interdisciplinary Chemistry |
Mikael Bols was born and grew up in Copenhagen, Denmark. He attended high school (Gentofte Statskole) from 1977 to 1980, and took a degree as chemical engineer at the Technical University of Denmark from 1980 to 1985. | 0 | Theoretical and Fundamental Chemistry |
4-Nitrophenol (also called p-nitrophenol or 4-hydroxynitrobenzene) is a phenolic compound that has a nitro group at the opposite position of the hydroxyl group on the benzene ring. | 0 | Theoretical and Fundamental Chemistry |
Zinc-finger nucleases consist of DNA binding domains that can precisely target a DNA sequence. Each zinc-finger can recognize codons of a desired DNA sequence, and therefore can be modularly assembled to bind to a particular sequence. These binding domains are coupled with a restriction endonuclease that can cause a double stranded break (DSB) in the DNA. Repair processes may introduce mutations that destroy functionality of the gene. | 1 | Applied and Interdisciplinary Chemistry |
The copper-based and NiTi-based shape-memory alloys are considered to be engineering materials. These compositions can be manufactured to almost any shape and size.
The yield strength of shape-memory alloys is lower than that of conventional steel, but some compositions have a higher yield strength than plastic or aluminum. The yield stress for Ni Ti can reach . The high cost of the metal itself and the processing requirements make it difficult and expensive to implement SMAs into a design. As a result, these materials are used in applications where the super elastic properties or the shape-memory effect can be exploited. The most common application is in actuation.
One of the advantages to using shape-memory alloys is the high level of recoverable plastic strain that can be induced. The maximum recoverable strain these materials can hold without permanent damage is up to for some alloys. This compares with a maximum strain for conventional steels. | 1 | Applied and Interdisciplinary Chemistry |
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