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The Jameson Cell has been adopted by Shell Canada and Syncrude for floating bitumen in the oil sands industry (see Bitumen flotation). Syncrude bought an additional eight 500 mm downcomers for its plant in 2012. | 1 | Applied and Interdisciplinary Chemistry |
In organic chemistry, an epoxide is a cyclic ether, where the ether forms a three-atom ring: two atoms of carbon and one atom of oxygen. This triangular structure has substantial ring strain, making epoxides highly reactive, more so than other ethers. They are produced on a large scale for many applications. In general, low molecular weight epoxides are colourless and nonpolar, and often volatile. | 0 | Theoretical and Fundamental Chemistry |
Bulk metallic glasses have been modeled using atomic scale simulations (within the density functional theory framework) in a similar manner to high entropy alloys. This has allowed predictions to be made about their behavior, stability and many more properties. As such, new bulk metallic glass systems can be tested and tailored for a specific purpose (e.g. bone replacement or aero-engine component) without as much empirical searching of the phase space or experimental trial and error. Ab-initio molecular dynamics (MD) simulation confirmed that the atomic surface structure of a Ni-Nb metallic glass observed by scanning tunneling microscopy is a kind of spectroscopy. At negative applied bias it visualizes only one soft of atoms (Ni) owing to the structure of electronic density of states calculated using ab-initio MD simulation.
One common way to try and understand the electronic properties of amorphous metals is by comparing them to liquid metals, which are similarly disordered, and for which established theoretical frameworks exist. For simple amorphous metals, good estimations can be reached by semi-classical modelling of the movement of individual electrons using the Boltzmann equation and approximating the scattering potential as the superposition of the electronic potential of each nucleus in the surrounding metal. To simplify the calculations, the electronic potentials of the atomic nuclei can be truncated to give a muffin-tin pseudopotential. In this theory, there are two main effects that govern the change of resistivity with increasing temperatures. Both are based on the induction of vibrations of the atomic nuclei of the metal as temperatures increase. One is, that the atomic structure gets increasingly smeared out as the exact positions of the atomic nuclei get less and less well defined. The other is the introduction of phonons. While the smearing out generally decreases the resistivity of the metal, the introduction of phonons generally adds scattering sites and therefore increases resistivity. Together, they can explain the anomalous decrease of resistivity in amorphous metals, as the first part outweighs the second. In contrast to regular crystalline metals, the phonon contribution in an amorphous metal does not get frozen out at low temperatures. Due to the lack of a defined crystal structure, there are always some phonon wavelengths that can be excited. While this semi-classical approach holds well for many amorphous metals, it generally breaks down under more extreme conditions. At very low temperatures, the quantum nature of the electrons leads to long range interference effects of the electrons with each other in what is called "weak localization effects". In very strongly disordered metals, impurities in the atomic structure can induce bound electronic states in what is called "Anderson localization", effectively binding the electrons and inhibiting their movement. | 1 | Applied and Interdisciplinary Chemistry |
The inclusion of nanoparticles in a solid or liquid medium can substantially change its mechanical properties, such as elasticity, plasticity, viscosity, compressibility. | 0 | Theoretical and Fundamental Chemistry |
Ziconotide is a synthetically made version of the ω-conotoxin made by the cone snail, that is used to treat severe pain and is delivered as an infusion into the cerebrospinal fluid using an intrathecal pump system. Ziconitide acts presynaptically on N-type calcium channels, blocking the receptors of this channel with high selectivity and affinity, | 1 | Applied and Interdisciplinary Chemistry |
In order to apply combinatorial chemistry for the synthesis of DNA-encoded chemical libraries, a Split-&-Pool approach was pursued. Initially a set of unique DNA-oligonucleotides (n) each containing a specific coding sequence is chemically conjugated to a corresponding set of small organic molecules. Consequently, the oligonucleotide-conjugate compounds are mixed ("Pool") and divided ("Split") into a number of groups (m). In appropriate conditions a second set of building blocks (m) are coupled to the first one and a further oligonucleotide which is coding for the second modification is enzymatically introduced before mixing again. This “split-&-pool” steps can be iterated a number of times (r) increasing at each round the library size in a combinatorial manner (i.e. (n x m)). Alternatively, peptide nucleic acids have been used to encode libraries prepared by "split-&-pool" method. A benefit of PNA-encoding is that the chemistry can be performed by standard SPPS. | 1 | Applied and Interdisciplinary Chemistry |
High levels of mixed-function oxidase activity have been studied for their activation effects in human colon carcinoma cell lines, to study the susceptibility to certain cancers. The research has been successful in mice but remains inconclusive in humans. | 1 | Applied and Interdisciplinary Chemistry |
Jung sets out his agenda and explains his method. The text that follows will contain several cycles of dreams recounted by a patient to a student of Jung. Each dream will be described and then analysed and interpreted with reference to Alchemical imagery and psychoanalytic theory. Jung is at pains to explain that the patient knew nothing of Jung's interpretations and so was not influenced in any way during the dream process.
Jung details an entire cycle of the patient's dreams, summarising the details of each then interpreting them in terms of their parallels with alchemical imagery to reveal their psychological content. | 1 | Applied and Interdisciplinary Chemistry |
The traditional approach to the study of acid–base physiology has been the empirical approach. The main variants are the base excess approach and the bicarbonate approach. The quantitative approach introduced by Peter A Stewart in 1978 is newer. | 0 | Theoretical and Fundamental Chemistry |
NMR spectroscopy uses the net spin of nuclei in a substance upon energy absorption to identify molecules. This has now become a standard spectroscopic tool within synthetic chemistry. One major use of NMR is to determine the bond connectivity within an organic molecule.
NMR imaging also uses the net spin of nuclei (commonly protons) for imaging. This is widely used for diagnostic purposes in medicine, and can provide detailed images of the inside of a person without inflicting any radiation upon them. In a medical setting, NMR is often known simply as "magnetic resonance" imaging, as the word nuclear has negative connotations for many people. | 0 | Theoretical and Fundamental Chemistry |
MK-886, or L-663536, is a leukotriene antagonist. It may perform this by blocking the 5-lipoxygenase activating protein (FLAP), thus inhibiting 5-lipoxygenase (5-LOX), and may help in treating atherosclerosis. | 1 | Applied and Interdisciplinary Chemistry |
Chichinin, Einfeld, Maul, and Gericke replaced the phosphor screen by a time-resolving delay line anode in order to be able to measure all three components of the initial product momentum vector simultaneously for each individual product particle arriving at the detector. This technique allows one to measure the three-dimensional product momentum vector distribution without having to rely on mathematical reconstruction methods which require the investigated systems to be cylindrically symmetric. Later, velocity mapping was added to 3D imaging. 3D techniques have been used to characterize several elementary photodissociation processes and bimolecular chemical reactions. | 0 | Theoretical and Fundamental Chemistry |
Desalting is used to remove salts from protein solutions, phenol or unincorporated nucleotides from nucleic acids or excess crosslinking or labeling reagents from conjugated proteins. Buffer exchange is used to transfer a protein solution into a buffer system appropriate for downstream applications such as ion exchange, electrophoresis or affinity chromatography. | 0 | Theoretical and Fundamental Chemistry |
The activity of HNMT, unlike that of DAO, cannot be measured by blood (serum) analysis.
Organs that produce DAO continuously release it into the bloodstream. DAO is stored in vesicular structures associated with the plasma membrane in epithelial cells. As a result, serum DAO activity can be measured, but not HNMT. This is because HNMT is primarily found within the cells of internal organs like the brain or liver and is not released to the bloodstream. Measuring intracellular HNMT directly is challenging. Therefore, diagnosis of HNMT activity is typically done indirectly by testing for known genetic variants. | 1 | Applied and Interdisciplinary Chemistry |
Since Serghidess solution was found to be one of the most accurate approximation of the implicit Colebrook–White equation, Niazkar modified the Serghidess solution to solve directly for the Darcy–Weisbach friction factor f for a full-flowing circular pipe.
Niazkar's solution is shown in the following:
Niazkar's solution was found to be the most accurate correlation based on a comparative analysis conducted in the literature among 42 different explicit equations for estimating Colebrook friction factor. | 1 | Applied and Interdisciplinary Chemistry |
Spathulenol is a tricyclic sesquiterpene alcohol which has a basic skeleton similar to the azulenes. It occurs in oregano among other plants. | 1 | Applied and Interdisciplinary Chemistry |
Characterization of the RRNPP family of quorum sensing regulators (which stands for proteins Rap, NprR, PrgX, PlcRd) were used in comparisons with ropB to postulate its structural functions. The Rap protein derived from Bacilli regulates sporulation, the NprR protein in Bacillus thuringiensis regulates necrotrophism, the PrgX protein regulates conjugation in Enterococcus faecalis, and PlcR protein regulates transcription of virulence factors in both Bacullis thuringiensis and Bacillus cereus. Similarities were observed in conserved asparagine residues on the TPR motifs of each of these proteins and in ropB. | 1 | Applied and Interdisciplinary Chemistry |
The Boltzmann equation is of use in galactic dynamics. A galaxy, under certain assumptions, may be approximated as a continuous fluid; its mass distribution is then represented by f; in galaxies, physical collisions between the stars are very rare, and the effect of gravitational collisions can be neglected for times far longer than the age of the universe.
Its generalization in general relativity is
where is the Christoffel symbol of the second kind (this assumes there are no external forces, so that particles move along geodesics in the absence of collisions), with the important subtlety that the density is a function in mixed contravariant-covariant phase space as opposed to fully contravariant phase space.
In physical cosmology the fully covariant approach has been used to study the cosmic microwave background radiation. More generically the study of processes in the early universe often attempt to take into account the effects of quantum mechanics and general relativity. In the very dense medium formed by the primordial plasma after the Big Bang, particles are continuously created and annihilated. In such an environment quantum coherence and the spatial extension of the wavefunction can affect the dynamics, making it questionable whether the classical phase space distribution f that appears in the Boltzmann equation is suitable to describe the system. In many cases it is, however, possible to derive an effective Boltzmann equation for a generalized distribution function from first principles of quantum field theory. This includes the formation of the light elements in Big Bang nucleosynthesis, the production of dark matter and baryogenesis. | 1 | Applied and Interdisciplinary Chemistry |
The Morton number is defined as
where g is the acceleration of gravity, is the viscosity of the surrounding fluid, the density of the surrounding fluid, the difference in density of the phases, and is the surface tension coefficient. For the case of a bubble with a negligible inner density the Morton number can be simplified to | 1 | Applied and Interdisciplinary Chemistry |
The use of depleted uranium (DU) in munitions is controversial because of questions about potential long-term health effects. Normal functioning of the kidney, brain, liver, heart, and numerous other systems can be affected by uranium exposure, because uranium is a toxic metal. Some people have raised concerns about the use of DU munitions because of its mutagenicity, teratogenicity in mice, neurotoxicity, and its suspected carcinogenic potential. Additional concerns address unexploded DU munitions leeching into groundwater over time.
The toxicity of DU is a point of medical controversy. Multiple studies using cultured cells and laboratory rodents suggest the possibility of leukemogenic, genetic, reproductive, and neurological effects from chronic exposure.
A 2005 epidemiology review concluded: "In aggregate the human epidemiological evidence is consistent with increased risk of birth defects in offspring of persons exposed to DU." The World Health Organization states that no risk of reproductive, developmental, or carcinogenic effects have been reported in humans due to DU exposure. This report has been criticized by Dr. Keith Baverstock for not including possible long-term effects. | 0 | Theoretical and Fundamental Chemistry |
The term "tholin" was coined by astronomer Carl Sagan and his colleague Bishun Khare to describe the difficult-to-characterize substances they obtained in his Miller–Urey-type experiments on the methane-containing gas mixtures such as those found in Titan's atmosphere. Their paper proposing the name "tholin" said:
Tholins are not one specific compound but rather are descriptive of a spectrum of molecules, including heteropolymers, that give a reddish, organic surface covering on certain planetary surfaces. Tholins are disordered polymer-like materials made of repeating chains of linked subunits and complex combinations of functional groups. Sagan and Khare note "The properties of tholins will depend on the energy source used and the initial abundances of precursors, but a general physical and chemical similarity among the various tholins is evident."
Some researchers in the field prefer a narrowed definition of tholins, for example S. Hörst wrote: "Personally, I try to use the word tholins only when describing the laboratory-produced samples, in part because we do not really know yet how similar the material we produce in the lab is to the material found on places like Titan or Triton (or Pluto!)." French researchers also use the term tholins only when describing the laboratory-produced samples as analogues. NASA scientists also prefer the word tholin for the products of laboratory simulations, and use the term refractory residues for actual observations on astronomical bodies. | 0 | Theoretical and Fundamental Chemistry |
Given certain conditions a homolytic splitting of the C-O bond in alkoxylamines can occur and a stable 2-centre 3 electron N-O radical can be formed that is able to initiate a polymerization reaction. The preconditions for an alkoxylamine suitable to initiate a polymerization are bulky, sterically obstructive substituents on the secondary amine, and the substituent on the oxygen should be able to form a stable radical, e.g. benzyl. | 0 | Theoretical and Fundamental Chemistry |
According to the rules exposed above, the phenanthrene molecule admits two different resonance structures: one of them presents a single circle in the center of the molecule, with each of the two adjacent rings having two double bonds; the other one has the two peripheral rings each with one circle, and the central ring with one double bond. According to Clar's rule, this last resonance structure gives the most important contribution to the determination of the properties of phenanthrene. | 0 | Theoretical and Fundamental Chemistry |
Reineke earned her bachelors degree at University of Wisconsin–Eau Claire. She moved to Arizona State University for her graduate studies and earned a masters degree in 1998. Reineke was a PhD student at the University of Michigan, where she was supervised by Michael O'Keeffe and Omar M. Yaghi. She was awarded the Wirt and Mary Cornell Prize for Outstanding Graduate Research. Reineke joined the California Institute of Technology as an National Institutes of Health postdoctoral fellow in 2000. | 1 | Applied and Interdisciplinary Chemistry |
The lone pair of electrons on the nitrogen atom is delocalized into the carbonyl group, thus forming a partial double bond between nitrogen and carbon. In fact the O, C and N atoms have molecular orbitals occupied by delocalized electrons, forming a conjugated system. Consequently, the three bonds of the nitrogen in amides is not pyramidal (as in the amines) but planar. This planar restriction prevents rotations about the N linkage and thus has important consequences for the mechanical properties of bulk material of such molecules, and also for the configurational properties of macromolecules built by such bonds. The inability to rotate distinguishes amide groups from ester groups which allow rotation and thus create more flexible bulk material.
The C-C(O)NR core of amides is planar. The C=O distance is shorter than the C-N distance by almost 10%. The structure of an amide can be described also as a resonance between two alternative structures: neutral (A) and zwitterionic (B).
It is estimated that for acetamide, structure A makes a 62% contribution to the structure, while structure B makes a 28% contribution (these figures do not sum to 100% because there are additional less-important resonance forms that are not depicted above). There is also a hydrogen bond present between the hydrogen and nitrogen atoms in the active groups. Resonance is largely prevented in the very strained quinuclidone.
In their IR spectra, amides exhibit a moderately intense ν band near 1650 cm. The energy of this band is about 60 cm lower than for the ν of esters and ketones. This difference reflects the contribution of the zwitterionic resonance structure. | 0 | Theoretical and Fundamental Chemistry |
In the year 2000 Meat and Livestock Australia (MLA) initiated a pilot group of beef and cattle farmers to partake in an environmental management system that would be soon implemented into the cattle industry. The standard aimed for the pilot group was ISO 14001 which is the current system standard for principal management systems and particularises the requirements for the introduction and maintenance of an environmental management system. During this period of development, Commonwealth and state governments who had been promoting EMS models in the agricultural sector began to introduce these methods to the nation's red meat industry. | 1 | Applied and Interdisciplinary Chemistry |
Fluoroantimonic acid is formed by combining hydrogen fluoride and antimony pentafluoride:
:SbF + 2 HF + HF
The speciation (i.e., the inventory of components) of "fluoroantimonic acid" is complex. Spectroscopic measurements show that fluoroantimonic acid consists of a mixture of HF-solvated protons, [ (such as ), and SbF-adducts of fluoride, [(SbF)F] (such as ). Thus, the formula "" is a convenient but oversimplified approximation of the true composition. Nevertheless, the extreme acidity of this mixture is evident from the exceptionally poor proton-accepting ability of the species present in solution. Hydrogen fluoride, a weak acid in aqueous solution that is normally not thought to have any appreciable Brønsted basicity at all, is in fact the strongest Brønsted base in the mixture, protonating to HF in the same way water protonates to HO in aqueous acid. As a result, the acid is often said to contain "naked protons", though the "free" protons are, in fact, always bonded to hydrogen fluoride molecules. It is the fluoronium ion that accounts for fluoroantimonic acid's extreme acidity. The protons easily migrate through the solution, moving from HF to HF, when present, by the Grotthuss mechanism.
Two related products have been crystallized from HF-SbF mixtures, and both have been analyzed by single crystal X-ray crystallography. These salts have the formulas and . In both salts, the anion is . As mentioned above, is weakly basic; the larger anion is expected to be a still weaker base. | 0 | Theoretical and Fundamental Chemistry |
The conformation assumed by a polymer chain in dilute solution can be modeled as a random walk of monomer subunits using a freely jointed chain model. However, this model does not account for steric effects. Real polymer coils are more closely represented by a self-avoiding walk because conformations in which different chain segments occupy the same space are not physically possible. This excluded volume effect causes the polymer to expand.
Chain conformation is also affected by solvent quality. The intermolecular interactions between polymer chain segments and coordinated solvent molecules have an associated energy of interaction which can be positive or negative. For a good solvent, interactions between polymer segments and solvent molecules are energetically favorable, and will cause polymer coils to expand. For a poor solvent, polymer-polymer self-interactions are preferred, and the polymer coils will contract. The quality of the solvent depends on both the chemical compositions of the polymer and solvent molecules and the solution temperature. | 0 | Theoretical and Fundamental Chemistry |
Cholesterol is precursor for steroid hormones including progestogens, glucocorticoids, mineralocorticoids, androgens, and estrogens. | 1 | Applied and Interdisciplinary Chemistry |
Isofurans are nonclassic eicosanoids formed nonenzymatically by free radical mediated peroxidation of arachidonic acid. The isofurans are similar to the isoprostanes and are formed under similar conditions, but contain a substituted tetrahydrofuran ring. The concentration of oxygen affects this process; at elevated oxygen concentrations, the formation of isofurans is favored whereas the formation of isoprostanes is disfavored. | 1 | Applied and Interdisciplinary Chemistry |
This article is about the discovery and development of 5α-reductase inhibitors (5-ARIs), also known as dihydrotestosterone (DHT) blockers. | 1 | Applied and Interdisciplinary Chemistry |
According to the U.S. National Park Service, and referring mostly to their employment in the American Civil War, a revetment is defined as a "retaining wall constructed to support the interior slope of a parapet. Made of logs, wood planks, fence rails, fascines, gabions, hurdles, sods, or stones, the revetment provided additional protection from enemy fire, and, most importantly, kept the interior slope nearly vertical. Stone revetments commonly survive. A few log revetments have been preserved due to high resin pine or cypress and porous sandy soils. After an entrenchment was abandoned, many log or rail revetments were scavenged for other uses, causing the interior slope to slump more quickly. An interior slope will appear more vertical if the parapet eroded with the revetment still in place." | 1 | Applied and Interdisciplinary Chemistry |
ADO is defined as the random non-amplification of one of the alleles present in a heterozygous sample. Some studies have reported the ADO rate of the MDA products to be 0–60%. This drawback decreases the accuracy of genotyping of single sample and misdiagnosis in other MDA involved applications. ADO appears to be independent of the fragment sizes and has been reported to have a similar rate in other single-cell techniques. Possible solutions are the use of different lysis conditions or to carry out multiple rounds of amplifications from the diluted MDA products since PCR mediated amplification from cultured cells has been reported to give lower ADO rates. | 1 | Applied and Interdisciplinary Chemistry |
The δS (pronounced delta 34 S) value is a standardized method for reporting measurements of the ratio of two stable isotopes of sulfur, S:S, in a sample against the equivalent ratio in a known reference standard. Presently, the most commonly used standard is Vienna-Canyon Diablo Troilite (VCDT). Results are reported as variations from the standard ratio in parts per thousand, per mil or per mille, using the ‰ symbol. Heavy and light sulfur isotopes fractionate at different rates and the resulting δS values, recorded in marine sulfate or sedimentary sulfides, have been studied and interpreted as records of the changing sulfur cycle throughout the earth's history. | 0 | Theoretical and Fundamental Chemistry |
The wind stress acting on the ocean surface is usually parameterized using the turbulent drag formula
where is the turbulent drag coefficient (usually determined empirically), is the air density, and is the wind velocity vector, usually taken at 10m above sea level. This parameterization is commonly referred to as resting ocean approximation. From now on we will refer to wind stress in resting ocean approximation as simply resting ocean wind stress.
On the other hand, relative wind stress makes use of the velocity of the surface wind relative to the velocity at the ocean surface , as follows,
where is the surface ocean velocity and thus, the terms with represent the wind velocity relative to the surface ocean velocity. Therefore, the difference between wind stress and relative wind stress is that relative wind stress takes into account the relative motion of the wind with respect to the surface ocean current. | 1 | Applied and Interdisciplinary Chemistry |
ARTADE (ARabidopsis Tiling Array-based Detection of Exons) is a database for the annotation of genome-wide tiling-array data in Arabidopsis | 1 | Applied and Interdisciplinary Chemistry |
*[https://instrumentationandcontrol.net/orifice-plate-calculator-size.html Online Orifice Plate Calculator] | 1 | Applied and Interdisciplinary Chemistry |
The Felkin model (1968) named after Hugh Felkin also predicts the stereochemistry of nucleophilic addition reactions to carbonyl groups. Felkin argued that the Cram model suffered a major drawback: an eclipsed conformation in the transition state between the carbonyl substituent (the hydrogen atom in aldehydes) and the largest α-carbonyl substituent. He demonstrated that by increasing the steric bulk of the carbonyl substituent from methyl to ethyl to isopropyl to isobutyl, the stereoselectivity also increased, which is not predicted by Cram's rule:
The Felkin rules are:
* The transition states are reactant-like.
* Torsional strain (Pitzer strain) involving partial bonds (in transition states) represents a substantial fraction of the strain between fully formed bonds, even when the degree of bonding is quite low. The conformation in the TS is staggered and not eclipsed with the substituent R skew with respect to two adjacent groups one of them the smallest in TS A.
: For comparison TS B is the Cram transition state.
* The main steric interactions involve those around R and the nucleophile but not the carbonyl oxygen atom.
* Attack of the nucleophile occurs according to the Dunitz angle (107 degrees), eclipsing the hydrogen, rather than perpendicular to the carbonyl.
* A polar effect or electronic effect stabilizes a transition state with maximum separation between the nucleophile and an electron-withdrawing group. For instance haloketones do not obey Cram's rule, and, in the example above, replacing the electron-withdrawing phenyl group by a cyclohexyl group reduces stereoselectivity considerably. | 0 | Theoretical and Fundamental Chemistry |
An approximate dependence of the diffusion coefficient on temperature in liquids can often be found using Stokes–Einstein equation, which predicts that
where
* D is the diffusion coefficient,
* T and T are the corresponding absolute temperatures,
* μ is the dynamic viscosity of the solvent. | 1 | Applied and Interdisciplinary Chemistry |
Targeted cancer therapies are designed to target the specific genes, proteins, or environments contributing to tumor cell growth or survival. After a period of prolonged treatment with these therapies, however, tumor cells may develop resistance. Although the mechanisms behind cancer drug resistance are poorly understood, potential causes include: target alteration, drug degradation, apoptosis escape, and epigenetic alterations. Resistance is well-recognised and poses a serious problem in cancer management.
To overcome this problem, a synthetic lethal partner can be identified. Genome-wide LOF screens using CRISPR-Cas9 can be used to screen for synthetic lethal partners. For this, a wild-type cell line and a tumor cell line containing the resistance-causing mutation are transduced with a CRISPR sgRNA library. The two cell lines are cultivated, and any under-represented or dead cells are analyzed to identify potential synthetic lethal partner genes. A recent study by Hinze et al. (2019) used this method to identify a synthetic lethal interaction between the chemotherapy drug asparaginase and two genes in the Wnt signalling pathway NKD2 and LGR6. | 1 | Applied and Interdisciplinary Chemistry |
Similar to other -ome based technologies, analysis of the transcriptome allows for an unbiased approach when validating hypotheses experimentally. This approach also allows for the discovery of novel mediators in signaling pathways. As with other -omics based technologies, the transcriptome can be analyzed within the scope of a multiomics approach. It is complementary to metabolomics but contrary to proteomics, a direct association between a transcript and metabolite cannot be established.
There are several -ome fields that can be seen as subcategories of the transcriptome. The exome differs from the transcriptome in that it includes only those RNA molecules found in a specified cell population, and usually includes the amount or concentration of each RNA molecule in addition to the molecular identities. Additionally, the transcritpome also differs from the translatome, which is the set of RNAs undergoing translation.
The term meiome is used in functional genomics to describe the meiotic transcriptome or the set of RNA transcripts produced during the process of meiosis. Meiosis is a key feature of sexually reproducing eukaryotes, and involves the pairing of homologous chromosome, synapse and recombination. Since meiosis in most organisms occurs in a short time period, meiotic transcript profiling is difficult due to the challenge of isolation (or enrichment) of meiotic cells (meiocytes). As with transcriptome analyses, the meiome can be studied at a whole-genome level using large-scale transcriptomic techniques. The meiome has been well-characterized in mammal and yeast systems and somewhat less extensively characterized in plants.
The thanatotranscriptome consists of all RNA transcripts that continue to be expressed or that start getting re-expressed in internal organs of a dead body 24–48 hours following death. Some genes include those that are inhibited after fetal development. If the thanatotranscriptome is related to the process of programmed cell death (apoptosis), it can be referred to as the apoptotic thanatotranscriptome. Analyses of the thanatotranscriptome are used in forensic medicine.
eQTL mapping can be used to complement genomics with transcriptomics; genetic variants at DNA level and gene expression measures at RNA level. | 1 | Applied and Interdisciplinary Chemistry |
* Award of the Ministry of Science and Higher Education (1985)
* Award of the Scientific Secretariat of the Polish Academy of Sciences (1980, 1989)
* Member of the Polish Chemical Society (1985) | 0 | Theoretical and Fundamental Chemistry |
The caloric theory is an obsolete scientific theory that heat consists of a self-repellent fluid called caloric that flows from hotter bodies to colder bodies. Caloric was also thought of as a weightless gas that could pass in and out of pores in solids and liquids. The "caloric theory" was superseded by the mid-19th century in favor of the mechanical theory of heat, but nevertheless persisted in some scientific literature—particularly in more popular treatments—until the end of the 19th century. | 1 | Applied and Interdisciplinary Chemistry |
Ferroparticles settle out of the suspension over time due to the inherent density difference between the particles and their carrier fluid. The rate and degree to which this occurs is one of the primary attributes considered in industry when implementing or designing an MR device. Surfactants are typically used to offset this effect, but at a cost of the fluid's magnetic saturation, and thus the maximum yield stress exhibited in its activated state. | 1 | Applied and Interdisciplinary Chemistry |
Kinesis, like a taxis or tropism, is a movement or activity of a cell or an organism in response to a stimulus (such as gas exposure, light intensity or ambient temperature).
Unlike taxis, the response to the stimulus provided is non-directional. The animal does not move toward or away from the stimulus but moves at either a slow or fast rate depending on its "comfort zone." In this case, a fast movement (non-random) means that the animal is searching for its comfort zone while a slow movement indicates that it has found it. | 1 | Applied and Interdisciplinary Chemistry |
Molten salt is salt which is solid at standard temperature and pressure but liquified due to elevated temperature. A salt that is liquid even at standard temperature and pressure is usually called a room-temperature ionic liquid, and molten salts are technically a class of ionic liquids. | 1 | Applied and Interdisciplinary Chemistry |
Examples of neutron activation systems include: pulsed fast neutron analysis (PFNA), fast neutron analysis (FNA), and thermal neutron analysis (TNA). All three systems are based on neutron interactions with the inspected items and examining the resultant gamma rays to determine the elements being radiated. TNA uses thermal neutron capture to generate the gamma rays. FNA and PFNA use fast neutron scattering to generate the gamma rays. Additionally, PFNA uses a pulsed collimated neutron beam. With this, PFNA generates a three-dimensional elemental image of the inspected item. | 0 | Theoretical and Fundamental Chemistry |
Thiosulfate ion is produced by the reaction of sulfite ion with elemental sulfur, and by incomplete oxidation of sulfides (e.g. pyrite oxidation). Sodium thiosulfate can be formed by disproportionation of sulfur dissolving in sodium hydroxide (similar to phosphorus). | 1 | Applied and Interdisciplinary Chemistry |
All of the experiments have led to at least one common conclusion: colloidal crystals may indeed mimic their atomic counterparts on appropriate scales of length (spatial) and time (temporal). Defects have been reported to flash by in the blink of an eye in thin films of colloidal crystals under oil using a simple optical microscope. But quantitatively measuring the rate of its propagation provides an entirely different challenge, which has been measured at somewhere near the speed of sound. | 0 | Theoretical and Fundamental Chemistry |
When building on top of bay mud layers or when dredging estuary bottoms, a variety of regulatory frameworks may arise. Normally in the United States, an Environmental Impact Report as well as a geotechnical investigation are conducted precedent to any major construction over bay mud. Combined, these reports have developed much of the data base extant on bay mud characteristics, frequently yielding original field data from soil borings. These data have demonstrated that in many locations the shallower bay muds contain concentrations of mercury, lead, chromium, petroleum hydrocarbons, PCBs, pesticides and other chemicals which exceed toxic limits: a geological record of human activities of the last century. These data are particularly important to consider when dredging of bay muds is contemplated as part of a development project. Such dredging can have impacts to receiving lands as soil contamination, but also water column impacts from sediment disturbance.
In the case of dredging within the United States, a permit is almost always required from the United States Army Corps of Engineers, after submission of extensive data on the project limits, chemical properties of the bay muds to be disturbed, a dredge disposal plan and often a complete Environmental Impact Statement pursuant to the National Environmental Policy Act. Further review by the United States Coast Guard would normally be required. Within individual state jurisdictions, such as California, an Environmental Impact Report must be filed for dredging of any significance; furthermore, agency reviews by the California Coastal Commission and the Regional Water Quality Control Board would normally be mandated. All of these regulatory bodies serve an important role in deciding whether an area may be dredged or not. However, the most important body is the California Environmental Quality Act (CEQA). This guiding legislation is the reason for Environmental Impact Reports, costly mitigation measures and arduous review processes. One of CEQA's main goals is to promote interagency cooperation in the review process of a project. This is one of the main reasons why it is the overseer of all projects in California.
For buildings proposed over bay mud layers, typically the municipality involved will, in addition to the usual engineering and design review issues common to all building projects (which are more complicated because of the site conditions), require an Environmental Impact Report [https://web.archive.org/web/20060906222150/http://ceres.ca.gov/topic/env_law/ceqa/guidelines/]. This process would include reviews by that city's building department, as well as applicable regional and state agencies such as those cited above for dredging projects, except that Coast Guard agencies would not typically be concerned. In developing in California, proposed development over bay mud layers would also have to go through a planning commission and a city council in order to be allowed. This process would respect the EIR, CEQA, and all the other bodies discussed above. In the case of San Francisco the project would have to get approved by the San Francisco Board of Supervisors.
In regards to San Francisco, some interesting negative externalities are being experienced due to the dredging of land by the Bay. The Millennium Towers, which were completed in 2008, are currently sinking. This has had a negative impact on the residents of this building. In response to this subsidence, San Francisco's city attorney has decided to file a lawsuit against the developer, because the developer failed to inform the residents of the accelerated speed that the building was sinking at. If this lawsuit results in success for San Francisco this could lead to policy changes being made in the future surrounding transparency between developers and potential buyers of the developed land. | 1 | Applied and Interdisciplinary Chemistry |
Put simply, ion suppression describes the adverse effect on detector response due to reduced ionisation efficiency for analyte(s) of interest, resulting from the presence of species in the sample matrix which compete for ionisation, or inhibit efficient ionisation in other ways. Use of MS/MS as a means of detection may give the impression that there are no interfering species present, since no chromatographic impurities are detected. However, species which are not isobaric may still have an adverse effect on the sensitivity, accuracy and precision of the assay owing to suppression of the ionisation of the analyte of interest.
Although the precise chemical and physical factors involved in ion suppression are not fully understood, it has been proposed that basicity, high concentration, mass and more intuitively, co-elution with the analyte of interest are factors which should not be ignored.
The most common atmospheric pressure ionisation techniques used in LC-MS/MS are electrospray ionization (ESI) and atmospheric pressure chemical ionization (APCI). APCI is less prone to pronounced ion suppression than ESI, an inherent property of the respective ionisation mechanisms.
In APCI, the sole source of ion suppression can be attributed to the change of colligative properties in the solute during evaporization (King et al, J. Am. Soc. Mass Spectrom 2000, 11, 942-950).
ESI has a more complex ionisation mechanism, relying heavily on droplet charge excess and as such there are many more factors to consider when exploring the cause of ion suppression. It has been widely observed that for many analytes, at high concentrations, ESI exhibits a loss of detector response linearity, perhaps due to reduced charge excess caused by analyte saturation at the droplet surface, inhibiting subsequent ejection of gas phase ions from further inside the droplet. Thus competition for space and/or charge may be considered as a source of ion suppression in ESI. Both physical and chemical properties of analytes (e.g. basicity and surface activity) determine their inherent ionisation efficiency. Biological sample matrices naturally tend to contain many endogenous species with high basicity and surface activity, hence the total concentration of these species in the sample will quickly reach levels at which ion suppression should be expected.
Another explanation of ion suppression in ESI considers the physical properties of the droplet itself rather than the species present. High concentrations of interfering components give rise to an increased surface tension and viscosity, giving a reduction in desolvation (solvent evaporation), which is known to have a marked effect of ionisation efficiency.
The third proposed theory for ion suppression in ESI relates to the presence of non-volatile species which can either cause co-precipitation of analyte in the droplet (thus preventing ionisation) or prevent the contraction of droplet size to the critical radius required for the ion evaporation and/or charge residue mechanisms to form gas phase ions efficiently.
It is worthwhile to consider that the degree of ion suppression may be dependent on the concentration of the analyte being monitored. A higher analyte/matrix ratio can give a reduced effect of ion suppression. | 0 | Theoretical and Fundamental Chemistry |
The introduction of eddy diffusivity and subsequently the turbulent Prandtl number works as a way to define a simple relationship between the extra shear stress and heat flux that is present in turbulent flow. If the momentum and thermal eddy diffusivities are zero (no apparent turbulent shear stress and heat flux), then the turbulent flow equations reduce to the laminar equations. We can define the eddy diffusivities for momentum transfer and heat transfer as and is the apparent turbulent shear stress and is the apparent turbulent heat flux.
The turbulent Prandtl number has been shown to not generally equal unity (e.g. Malhotra and Kang, 1984; Kays, 1994; McEligot and Taylor, 1996; and Churchill, 2002). It is a strong function of the molecular Prandtl number amongst other parameters and the Reynolds Analogy is not applicable when the molecular Prandtl number differs significantly from unity as determined by Malhotra and Kang; and elaborated by McEligot and Taylor and Churchill | 1 | Applied and Interdisciplinary Chemistry |
In eukaryotic transcription of mRNAs, terminator signals are recognized by protein factors that are associated with the RNA polymerase II and which trigger the termination process. The genome encodes one or more polyadenylation signals. Once the signals are transcribed into the mRNA, the proteins cleavage and polyadenylation specificity factor (CPSF) and cleavage stimulation factor (CstF) transfer from the carboxyl terminal domain of RNA polymerase II to the poly-A signal. These two factors then recruit other proteins to the site to cleave the transcript, freeing the mRNA from the transcription complex, and add a string of about 200 A-repeats to the 3' end of the mRNA in a process known as polyadenylation. During these processing steps, the RNA polymerase continues to transcribe for several hundred to a few thousand bases and eventually dissociates from the DNA and downstream transcript through an unclear mechanism; there are two basic models for this event known as the torpedo and allosteric models. | 1 | Applied and Interdisciplinary Chemistry |
Of the three types of anchoring junctions, only two are involved in cell-cell interactions: adherens junctions and desmosomes. Both are found in many types of cells. Adjacent epithelial cells are connected by adherens junctions on their lateral membranes. They are located just below tight junctions. Their function is to give shape and tension to cells and tissues and they are also the site of cell-cell signaling. Adherens junctions are made of cell adhesion molecules from the cadherin family. There are over 100 types of cadherins, corresponding to the many different types of cells and tissues with varying anchoring needs. The most common are E-, N- and P-cadherins. In the adherens junctions of epithelial cells, E-cadherin is the most abundant.
Desmosomes also provide strength and durability to cells and tissues and are located just below adherens junctions. They are sites of adhesion and do not encircle the cell. They are made of two specialized cadherins, desmoglein and desmocollin. These proteins have extracellular domains that interact with each other on adjacent cells. On the cytoplasmic side, plakins form plaques which anchor the desmosomes to intermediate filaments composed of keratin proteins. Desmosomes also play a role in cell-cell signaling. | 1 | Applied and Interdisciplinary Chemistry |
A thermal bar is a hydrodynamic feature that forms around the edges of holomictic lakes during the seasonal transition to stratified conditions, due to the shorter amount of time required for shallow areas of the lake to stratify. | 1 | Applied and Interdisciplinary Chemistry |
It is theorized that the process of making testosterone from cholesterol, needs magnesium to function properly.
Studies have shown that significant gains in testosterone occur after taking 8-10 mg magnesium/kg body weight/day. | 1 | Applied and Interdisciplinary Chemistry |
Carl Jacob Löwig (17 March 1803 – 27 March 1890) was a German chemist and discovered bromine independently of Antoine Jérôme Balard.
He received his PhD at the University of Heidelberg for his work with Leopold Gmelin.
During his research on mineral salts he discovered bromine in 1825, as a brown gas evolving after the salt was treated with chlorine.
After working at the University of Heidelberg and the University of Zurich he became the successor to Robert Wilhelm Bunsen at the University of Breslau. He worked and lived in Breslau until his death in 1890. | 1 | Applied and Interdisciplinary Chemistry |
Photo-induced Rydberg ionization (PIRI) was developed following REMPI experiments on electronic autoionization of low-lying Rydberg states of carbon dioxide. In REMPI photoelectron experiments, it was determined that a two-photon ionic core photoabsorption process (followed by prompt electronic autoionization) could dominate the direct single photon absorption in the ionization of some Rydberg states of carbon dioxide. These sorts of two excited electron systems had already been under study in the atomic physics, but there the experiments involved high order Rydberg states. PIRI works because electronic autoionization can dominate direct photoionization (photoionization). The circularized near-threshold Rydberg state is more likely to undergo a core photoabsorption than to absorb a photon and directly ionize the Rydberg state. PIRI extends the near-threshold spectroscopic techniques to allow access to the electronic states (including dissociative molecular states and other hard to study systems) as well as the vibrational states of molecular ions. | 0 | Theoretical and Fundamental Chemistry |
Methyl isocyanate (MIC) is an organic compound with the molecular formula CHNCO. Synonyms are isocyanatomethane and methyl carbylamine. Methyl isocyanate is an intermediate chemical in the production of carbamate pesticides (such as carbaryl, carbofuran, methomyl, and aldicarb). It has also been used in the production of rubbers and adhesives. As an extremely toxic and irritating compound, it is very hazardous to human health. MIC was the principal toxicant involved in the Bhopal gas disaster, which eventually killed around 20,000 people in total as per official figures. It is also a very potent lachrymatory agent. | 0 | Theoretical and Fundamental Chemistry |
Multiplexed error-robust fluorescence in situ hybridization is a highly multiplexed version of smFISH. It uses combinatorial labeling, followed by imaging, and then error-resistant encoding to capture a high number of RNA molecules and spatial localization within the cell. The capture of a large number of RNA molecules enables elucidation of gene regulatory networks, prediction of function of unannotated genes, and identification of RNA molecule distribution patterns, which correlate with their associated proteins. | 1 | Applied and Interdisciplinary Chemistry |
DEPBT (3-(diethoxyphosphoryloxy)-1,2,3-benzotriazin-4(3H)-one) is a peptide coupling reagent used in peptide synthesis. It shows remarkable resistance to racemization.
Fmoc-Dab(Mtt)-OH, a commercially available amino acid building block for solid-phase peptide synthesis (SPPS), was proven to undergo rapid lactamization, instead of reacting with the N-terminal end of the peptide. Compared with other commercially available coupling reagents, DEPBT has shown superior performance in coupling Fmoc-Dab(Mtt)-OH to the N-terminal end of peptide during SPPS, though the approach was regarded as costly and tedious. | 1 | Applied and Interdisciplinary Chemistry |
Nitrogen is an important nutrient for plant and animal growth. Atmospheric nitrogen is less biologically available than dissolved nitrogen in the form of ammonia and nitrates. Availability of dissolved nitrogen may contribute to algal blooms. Ammonia and organic forms of nitrogen are often measured as Total Kjeldahl Nitrogen, and analysis for inorganic forms of nitrogen may be performed for more accurate estimates of total nitrogen content. | 0 | Theoretical and Fundamental Chemistry |
Gallic acid is formed from 3-dehydroshikimate by the action of the enzyme shikimate dehydrogenase to produce 3,5-didehydroshikimate. This latter compound spontaneously rearranges to gallic acid. | 1 | Applied and Interdisciplinary Chemistry |
The organic matter in soil derives from plants, animals and microorganisms. In a forest, for example, leaf litter and woody material falls to the forest floor. This is sometimes referred to as organic material. When it decays to the point in which it is no longer recognizable, it is called soil organic matter. When the organic matter has broken down into a stable substance that resist further decomposition it is called humus. Thus soil organic matter comprises all of the organic matter in the soil exclusive of the material that has not decayed.
An important property of soil organic matter is that it improves the capacity of a soil to hold water and nutrients, and allows their slow release, thereby improving the conditions for plant growth. Another advantage of humus is that it helps the soil to stick together which allows nematodes, or microscopic bacteria, to easily decay the nutrients in the soil.
There are several ways to quickly increase the amount of humus. Combining compost, plant or animal materials/waste, or green manure with soil will increase the amount of humus in the soil.
# Compost: decomposed organic material.
# Plant and animal material and waste: dead plants or plant waste such as leaves or bush and tree trimmings, or animal manure.
# Green manure: plants or plant material that is grown for the sole purpose of being incorporated with soil.
These three materials supply nematodes and bacteria with nutrients for them to thrive and produce more humus, which will give plants enough nutrients to survive and grow.
Soil organic matter is crucial to all ecology and to all agriculture, but it is especially emphasized in organic farming, where it is relied upon especially heavily. | 0 | Theoretical and Fundamental Chemistry |
Signal pheromones cause short-term changes, such as the neurotransmitter release that activates a response. For instance, GnRH molecule functions as a neurotransmitter in rats to elicit lordosis behavior. | 1 | Applied and Interdisciplinary Chemistry |
By sequence similarity, most sigma factors are σ-like (). They have four main regions (domains) that are generally conserved:
N-terminus --------------------- C-terminus
The regions are further subdivided. For example, region 2 includes 1.2 and 2.1 through 2.4.
Domain 1.1 is found only in "primary sigma factors" (RpoD, RpoS in E.coli; "Group 1"). It is involved in ensuring the sigma factor will only bind the promoter when it is complexed with the RNA polymerase. Domains 2-4 each interact with specific promoter elements and with RNAP. Region 2.4 recognizes and binds to the promoter −10 element (called the "Pribnow box"). Region 4.2 recognizes and binds to the promoter −35 element.
Not every sigma factor of the σ family contains all the domains. Group 2, which includes RpoS, is very similar to Group 1 but lacks domain 1. Group 3 also lacks domain 1, and includes σ. Group 4, also known as the Extracytoplasmic Function (ECF) group, lack both σ1.1 and σ3. RpoE is a member.
Other known sigma factors are of the σ/RpoN () type. They are functional sigma factors, but they have significantly different primary amino acid sequences. | 1 | Applied and Interdisciplinary Chemistry |
*H. Schubert, History of British Iron and Steel Industry c.450 BC to AD 1775 (1957), 272–291.
*A. den Ouden, "The Production of Wrought Iron in Finery Hearths", Historical Metallurgy 15(2) (1981), 63–87 and 16(1) (1982), 29–33.
*K-G. Hildebrand, Swedish Iron in the Seventeenth and Eighteenth Centuries: Export Industry Before Industrialization (Stockholm 1992).
*P. King, The Cartel in Oregrounds Iron: Trading in the Raw Material for Steel During the 18th century", Journal of Industrial History' 6 (2003), 25–48. | 1 | Applied and Interdisciplinary Chemistry |
In physics, the Lamb–Mössbauer factor (LMF, after Willis Lamb and Rudolf Mössbauer) or elastic incoherent structure factor (EISF) is the ratio of elastic to total incoherent neutron scattering, or the ratio of recoil-free to total nuclear resonant absorption in Mössbauer spectroscopy. The corresponding factor for coherent neutron or X-ray scattering is the Debye–Waller factor; often, that term is used in a more generic way to include the incoherent case as well.
When first reporting on recoil-free resonance absorption, Mössbauer (1959) cited relevant theoretical work by Lamb (1939). The first use of the term "Mössbauer–Lamb factor" seems to be by Tzara (1961); from 1962 on, the form "Lamb–Mössbauer factor" came into widespread use.
Singwi and Sjölander (1960) pointed out the close relation to incoherent neutron scattering. With the invention of backscattering spectrometers, it became possible to measure the Lamb–Mössbauer factor as a function of the wavenumber (whereas Mössbauer spectroscopy operates at a fixed wavenumber). Subsequently, the term elastic incoherent structure factor became more frequent. | 0 | Theoretical and Fundamental Chemistry |
Ryōji Noyori was born in Kobe, Japan. Early in his school days Ryoji was interested in physics. His interest was kindled by the famous physicist Hideki Yukawa (1949 Nobel Prize in Physics winner), a close friend of his father. Later, he became fascinated with chemistry, after hearing a presentation on nylon at an industrial exposition. He saw the power of chemistry as being the ability to "produce high value from almost nothing". He was a student at the School of Engineering (Department of Industrial Chemistry) of the Kyoto University, where he graduated in 1961. He subsequently obtained a Master's degree in Industrial Chemistry from the Graduate School of Engineering of the Kyoto University. Between 1963 and 1967, he was a research associate at the School of Engineering of the Kyoto University, and an instructor in the research group of Hitoshi Nozaki. Noyori obtained a Doctor of Engineering degree (DEng) from the Kyoto University in 1967. He became an associate professor at the same university in 1968. After postdoctoral work with Elias J. Corey at Harvard he returned to Nagoya, becoming a full professor in 1972. He is still based at Nagoya, and served as president of RIKEN, a multi-site national research initiative with an annual budget of $800 million, from 2003 to 2015. | 0 | Theoretical and Fundamental Chemistry |
The weight a foil can lift is proportional to its lift coefficient, the density of the fluid, the foil area and its speed squared. The following shows the lifting ability of a flat plate with span 10 metres and area 10 square metres moving at a speed of 10 m/s at different altitudes and water depths. It uses the lift at an altitude of 11 km as a datum to show how the lift increases with decreasing altitude (increasing air density). It also shows the influence of ground effect and then the effect of increase in density going from air to water.
height 11 km: lift 1.0 (datum for comparison)
5 m 3.4
in ground effect 4.1
water surface-planing 1,280
just submerged 1,420
depth 5 m 2,840
10 km 2,860 | 1 | Applied and Interdisciplinary Chemistry |
Ali Akbar Moosavi-Movahedi's research career has been mostly marked on thermodynamics of protein denaturation especially by surfactants, protein folding/unfolding, protein glycation, biophysics of molecular diabetes, amyloid and protein aggregation and fibrillation, bioactive peptides, nutraceuticals, functional foods and artificial enzyme. He has been selected as the chair of UNESCO Chair on Interdisciplinary Research in Diabetes, University of Tehran which is mostly oriented in the area of oxidative stress and diabetes complications.
He has established a highly equipped BCL laboratory for collaborations and working with different international research groups.
Ali A. Moosavi-Movahedi has been one of the pioneering scientists in establishing the first PhD programs in Biochemistry and Biophysics in Iran. He has initiated a few science and technology institutional foundations in Iran. His publications include 20 books and numerous full research papers published mostly in international research journals, mainly around structural elucidation of proteins, enzymes, and DNA strands. He is the chair of Center of Excellence in Biothermodynamics and national committee member of the International Science Council (ISC) (previous name: ICSU) at University of Tehran.
He is a member of a few national and international scientific societies and is currently the president of Iran Society of Biophysical Chemistry(ISOBC). Several awards are given to researchers by the society such as ISOBC Global Science Contribution for senior highly cited distinguished scientists, ISOBC for talented young (under 35 year) researcher, Moosavi-Movahedi Award for young (under 40 years) eminent PhD that confer to scientists in Annual ISOBC Congress. ISOBC is a member of the International Union of Biochemistry and Molecular Biology (IUBMB) and the European Biophysical Societies' Association (EBSA).
He is the founding member of the Federation of Iran Bioscience Societies (FIrBS), Universal Scientific Education and Research Network (USERN), Biochemical Society of Iran, Iranian Biology Society.
He is the Editor-in-Chief of a journal named "Science Cultivation," which publishes aimed popularization of science, policy research in science and technology, promotion of science, assisting managers and policymakers in scientific centers, steering the direction of research for scientific elites and innovators in science and technology. This Journal attempts to create the necessary context for cultivating and fertilizing new areas of sciences through monitoring, culture building, and scientific capacity building.
He supports organizing National, Regional, and International conferences in the field of Biophysical Chemistry, biothermodynamics, Biomolecular Sciences and also in the area of enculturing science and technology advancements.
He has published a new international book entitled "Rationality and Scientific Lifestyle for Health" Springer 2021. | 0 | Theoretical and Fundamental Chemistry |
The technique is applied to conversions that proceed via unimolecular pathways. 2-Acetoxydioxane, when heated at 425 °C converts to the highly reactive dioxene, via loss of acetic acid.
2-Furonitrile has been prepared by flash-dehydration of 2-furoic acid amide or oxime over molecular sieves. The strained ring benzocyclobutenone has been prepared by FVP from a simple benzoyl chloride precursor. | 0 | Theoretical and Fundamental Chemistry |
LAAM, or levomethadyl acetate, is the levo isomer of acetylmethadol, or α-methadyl acetate. The dextro isomer, d-alphacetylmethadol (d-α-acetylmethadol), is more potent but shorter acting. The levo isomer is also less toxic with an in mice of 110 mg/kg s.c. and 172.8 mg/kg orally as opposed to s of 61 mg/kg s.c. and 118.3 mg/kg orally for dl-α-methadyl acetate. It has a melting point of 215 °C and a molecular weight of 353.50. β-methadyl acetate also exists, however it is more toxic and less active than α-methadyl acetate and has no current medical use. | 0 | Theoretical and Fundamental Chemistry |
Rasagiline is molecularly a propargylamine derivative. The form brought to market by Teva and its partners is the mesylate salt, and was designated chemically as: 1H-Inden-1-amine-2,3-dihydro-N-2-propynyl-(1R)-methanesulfonate. | 0 | Theoretical and Fundamental Chemistry |
Given the biochemical network:
where and are fixed species to ensure the system is open. The system equation can be written as:
So that:
The elements of the rate vector will be rate equations that are functions of one or more species and parameters, p. In the example, these might be simple mass-action rate laws such as where is the rate constant parameter. The particular laws chosen will depend on the specific system under study. Assuming mass-action kinetics, the above equation can be written in complete form as: | 1 | Applied and Interdisciplinary Chemistry |
The Tebbe reagent is synthesized from titanocene dichloride and trimethylaluminium in toluene solution.
::CpTiCl + 2 Al(CH) → CH + CpTiCHAlCl(CH) + Al(CH)Cl
After about 3 days, the product is obtained after recrystallization to remove Al(CH)Cl. Although syntheses using the isolated Tebbe reagent give a cleaner product, successful procedures using the reagent "in situ" have been reported. Instead of isolating the Tebbe reagent, the solution is merely cooled in an ice bath or dry ice bath before adding the starting material.
An alternative but less convenient synthesis entails the use of dimethyltitanocene (Petasis reagent):
::CpTi(CH) + Al(CH)Cl → CpTiCHAlCl(CH) + CH
One drawback to this method, aside from requiring CpTi(CH), is the difficulty of separating product from unreacted starting reagent. | 0 | Theoretical and Fundamental Chemistry |
The catalysis of this mechanism is initiated by the deprotonation of TPP at the thiazolium ring. This carbanion then binds to the carbonyl of the donor substrate thus cleaving the bond between C-2 and C-3. This keto fragment remains covalently bound to the C-2 carbon of TPP. The donor substrate is then released, and the acceptor substrate enters the active site where the fragment, which is bound to the intermediate α-β-dihydroxyethyl thiamin diphosphate, is then transferred to the acceptor.
Experiments have also been conducted that test the effect replacing alanine for the amino acids at the entrance to the active site, Arg359, Arg528, and His469, which interact with the phosphate group of the substrate. This replacement creates a mutant enzyme with impaired catalytic activity. | 0 | Theoretical and Fundamental Chemistry |
The worlds first oil well was drilled in 1859 by Edwin Drake at what is now called the Drake Well in Cherrytree Township, Pennsylvania. Drakes well is considered the first because it was drilled, not dug, and used a steam engine. There also was a company associated with it, and it sparked a major oil drilling boom.
Prior to the first well drilled by Drake, there was activity in various parts of the world in the mid-19th century. A group directed by Major Alexeyev of the Bakinskii Corps of Mining Engineers hand-drilled a well in the Baku region of Bibi-Heybat in 1846. There were engine-drilled wells in West Virginia in the same year as Drakes well. An early commercial well was hand dug in Poland in 1853, and another in nearby Romania in 1857. At around the same time the worlds first, small, oil refinery was opened at Jasło in Poland, with a larger one opened at Ploiești in Romania shortly after. Romania is the first country in the world to have had its annual crude oil output officially recorded in international statistics: 275 tonnes for 1857.
In 1858, Georg Christian Konrad Hunäus found a significant amount of petroleum while drilling for lignite in Wietze, Germany. Wietze later provided about 80% of German consumption in the Wilhelminian Era. The production stopped in 1963, but Wietze has hosted a Petroleum Museum since 1970.
Oil sands have been mined since the 18th century. In Wietze in lower Saxony, natural asphalt/bitumen has been explored since the 18th century. Both in Pechelbronn as in Wietze, the coal industry dominated the petroleum technologies.
Chemist James Young in 1847 noticed a natural petroleum seepage in the coal mine at riddings Alfreton, Derbyshire from which he distilled a light thin oil suitable for use as lamp oil, at the same time obtaining a more viscous oil suitable for lubricating machinery. In 1848, Young set up a small business refining crude oil.
Young eventually succeeded, by distilling cannel coal at low heat, in creating a fluid resembling petroleum, which when treated in the same way as the seep oil gave similar products. Young found that by slow distillation he could obtain several useful liquids from it, one of which he named "paraffine oil" because at low temperatures it congealed into a substance resembling paraffin wax.
The production of these oils and solid paraffin wax from coal formed the subject of his patent dated October 17, 1850. In 1850, Young & Meldrum and Edward William Binney entered into partnership under the title of E.W. Binney & Co. at Bathgate in West Lothian and E. Meldrum & Co. at Glasgow; their works at Bathgate were completed in 1851 and became the first truly commercial oil-works in the world with the first modern oil refinery.
The worlds first oil refinery was built in 1856 by Ignacy Łukasiewicz. His achievements also included the discovery of how to distill kerosene from seep oil, the invention of the modern kerosene lamp (1853), the introduction of the first modern street lamp in Europe (1853), and the construction of the worlds first modern oil "mine" (1854). at Bóbrka, near Krosno (still operational as of 2020).
The demand for petroleum as a fuel for lighting in North America and around the world quickly grew.
The first commercial oil well in Canada became operational in 1858 at Oil Springs, Ontario (then Canada West). Businessman James Miller Williams dug several wells between 1855 and 1858 before discovering a rich reserve of oil four metres below ground. Williams extracted 1.5 million litres of crude oil by 1860, refining much of it into kerosene lamp oil. Williamss well became commercially viable a year before Drakes Pennsylvania operation and could be argued to be the first commercial oil well in North America. The discovery at Oil Springs touched off an oil boom which brought hundreds of speculators and workers to the area. Advances in drilling continued into 1862 when local driller Shaw reached a depth of 62 metres using the spring-pole drilling method. On January 16, 1862, after an explosion of natural gas, Canada's first oil gusher came into production, shooting into the air at a recorded rate of per day. By the end of the 19th century the Russian Empire, particularly the Branobel company in Azerbaijan, had taken the lead in production. | 0 | Theoretical and Fundamental Chemistry |
Maximum valences for the elements are based on the data from list of oxidation states of the elements. They are shown by the color code at the bottom of the table. | 0 | Theoretical and Fundamental Chemistry |
While there are no chemical or practical uses for the NanoKid molecule or any of its known derivatives outside of the classroom, James Tour has turned the NanoKid into a lifelike character to educate children in the sciences. The goals of the outreach program, as described on the NanoKids website, are:
*“To significantly increase students’ comprehension of chemistry, physics, biology, and materials science at the molecular level."
*"To provide teachers with conceptual tools to teach nanoscale science and emerging molecular technology."
*"To demonstrate that art and science can combine to facilitate learning for students with diverse learning styles and interests."
*"To generate informed interest in nanotechnology that encourages participation in and funding for research in the field.”
To accomplish these goals, several video clips, CDs, as well as interactive computer programs were created. Tour and his team invested over $250,000 into their project. In order to raise the funds for this endeavor, Tour used unrestricted funds from his professorship and small grants from Rice University, the Welch Foundation, the nanotech firm Zyvex, and Texas A&M University. Tour also received $100,000 in 2002 from the Small Grants for Exploratory Research program, a division of the National Science Foundation.
The main characters in the videos are animated versions of the NanoKid. They star in several videos and explain various scientific concepts, such as the periodic table, DNA, and covalent bonding.
Rice conducted several studies into the effectiveness of using the NanoKids materials. These studies found mostly positive results for the use of the NanoKids in the classroom. A 2004–2005 study in two schools districts in Ohio and Kentucky found that using NanoKids led to a 10–59% increase in understanding of the material presented. Additionally, it was found that 82% of students found that NanoKids made learning science more interesting. | 1 | Applied and Interdisciplinary Chemistry |
These experiments address various important questions in evolutionary biology: does evolution proceed in small steps or in large leaps; is evolution reversible; how does complexity evolve? It has been shown that slight mutations in the amino acid sequence of hormone receptors determine an important change in their preferences for hormones. These changes mean huge steps in the evolution of the endocrine system. Thus very small changes at the molecular level may have enormous consequences. The Thornton lab has also been able to show that evolution is irreversible studying the glucocorticoid receptor. This receptor was changed by seven mutations in a cortisol receptor, but reversing these mutations didn't give the original receptor back. Indicating that epistasis plays a major role in protein evolution – an observation that in combination with the observations of several examples of parallel evolution, support the neutral network model mentioned above. Other earlier neutral mutations acted as a ratchet and made the changes to the receptor irreversible. These different experiments on receptors show that, during their evolution, proteins are greatly differentiated and this explains how complexity may evolve. A closer look at the different ancestral hormone receptors and the various hormones shows that at the level of interaction between single amino acid residues and chemical groups of the hormones arise by very small but specific changes. Knowledge about these changes may for example lead to the synthesis of hormonal equivalents capable of mimicking or inhibiting the action of a hormone, which might open possibilities for new therapies.
Given that ASR has revealed a tendency towards ancient thermostability and enzymatic promiscuity, ASR poses as a valuable tool for protein engineers who often desire these traits (producing effects sometimes greater than current, rationally lead tools). ASR also promises to resurrect phenotypically similar ancient organisms which in turn would allow evolutionary biochemists to probe the story of life. Proponents of ASR such as Benner state that through these and other experiments, the end of the current century will see a level of understanding in biology analogous to the one that arose in classical chemistry in the last century. | 1 | Applied and Interdisciplinary Chemistry |
For in-situ bonded face sheets the core is closed-cell foam. The goal of in-situ bonding is to create a metallic bonding between the foam core and face sheets. This is achieved in three ways. A foamable precursor is expanded between two face sheets. When the liquid foam comes in contact with the solid face sheets a metallic bond is established. This is difficult to realize as the oxidation of both aluminium face sheets and foam prevent forming a sound bonding. There is also a risk of melting the face sheets. This procedure is successful when steel is used as face sheets instead of aluminium, while the foam core is aluminium.
Another strategy is to rapidly solidify the surface of a foamable molten metal before it can foam into a dense skin while the interior of the metal evolves to a foam structure. This process yields in an integral-type foam structure. Integral foam sandwich is made of aluminium alloys (AlCu4, AlSi9Cu3) and magnesium alloys (AZ91, AM60). In this process the material for the core and face sheet is the same.
The third way to achieve in-situ bonding consists of compaction of metal powders together with face sheets. This sandwich-compact assembly goes through several rolling steps to attain desired precursor and face sheet thickness. After which this three-layer composite is heated to transform the core layer into foam. The melting point of the face sheet material is above the melting point of the foamable precursor material. The precursor composition is usually Al-Si, Al-Si-Cu or Al-Si-Mg alloys while the face sheets are 3xxx, 5xxx and 6xxx series aluminium alloys. | 0 | Theoretical and Fundamental Chemistry |
In the context of electron transfer, these groups enhance the oxidizing power tendency of the attached species. For example, Tetracyanoethylene serves as an oxidant due to its attachment to four cyano substituents, which are electron-withdrawing groups.
Oxidants with EWGs are stronger than the parent compound. Acetylferrocenium is 300 mV more oxidizing than ferrocene. | 0 | Theoretical and Fundamental Chemistry |
The scallop theorem is a consequence of the subsequent forces applied to the organism as it swims from the surrounding fluid. For an incompressible Newtonian fluid with density and dynamic viscosity , the flow satisfies the Navier–Stokes equations:
where denotes the velocity of the fluid. However, at the low Reynolds number limit, the inertial terms of the Navier-Stokes equations on the left-hand side tend to zero. This is made more apparent by nondimensionalizing the Navier–Stokes equations. By defining a characteristic velocity and length, and , we can cast our variables to dimensionless form:
where the dimensionless pressure is appropriately scaled for flow with significant viscous effects. Plugging these quantities into the Navier-Stokes equations gives us:
And by rearranging terms, we arrive at a dimensionless form:
where is the Reynolds number. In the low Reynolds number limit (as ), the LHS tends to zero and we arrive at a dimensionless form of Stokes equations. Redimensionalizing yields: | 1 | Applied and Interdisciplinary Chemistry |
The chemistry component incorporates both bioavailability and potential effects on benthic community. The potential of sediment toxicity for a given site is based on a linear regression model (LRM). A chemical score index (CSI) of the contaminant describes the magnitude of exposure relative to benthic community disturbance. An optimal set of index-specific thresholds are selected for the chemistry component by statistically comparing several candidates to evaluate which set exhibited greatest overall agreement (Bay and Weisberg, 2012). The magnitude of sediment toxicity is determined by multiple toxicity tests conducted in the lab to complement chemistry component. Toxicity LOE are determined by the mean of toxicity category score from all relevant tests. Development of LOE for benthic component is based on community metrics and abundance. Several indices such as benthic response index (BRI), benthic biotic integrity (IBI), and relative biotic index (RBI) are utilized to assess biological response of the benthic community. The median score of all individual indices will establish benthic LOE.
Each component of the triad is assigned a response category: minimal, low, moderate, or high disturbance relative to background conditions. Individual LOEs are ranked into categories by comparing test results of each component to established thresholds (Bay and Weisberg, 2012). Integration of benthos and toxicity LOE classify the severity and effects of contamination. LOE of chemistry and toxicity are combined to assign the potential of chemically-mediated effects.
A site is assigned an impact category by integrating the severity of effect and the potential of chemically mediated effects. The conditions of individual sites of concern are assigned an impact category between 1 and 5 (with 1 being unimpacted and 5 being clearly impacted by contamination). The SQT triad can also classify impact as inconclusive in cases when LOE between components are in disagreement or additional information is required (Bay and Weisberg, 2012). | 1 | Applied and Interdisciplinary Chemistry |
Enolate anions are electronically related to allyl anions. The anionic charge is delocalized over the oxygen and the two carbon sites. Thus they have the character of both an alkoxide and a carbanion.
Although they are often drawn as being simple salts, in fact they adopt complicated structures often featuring aggregates. | 0 | Theoretical and Fundamental Chemistry |
Animals that are capable of smell detect aroma compounds with their olfactory receptors. Olfactory receptors are cell-membrane receptors on the surface of sensory neurons in the olfactory system that detect airborne aroma compounds. Aroma compounds can then be identified by gas chromatography-olfactometry, which involves a human operator sniffing the GC effluent.
In mammals, olfactory receptors are expressed on the surface of the olfactory epithelium in the nasal cavity. | 0 | Theoretical and Fundamental Chemistry |
Microcystins have a common structural framework of D-Ala-X--Z-Adda-D-γ-Glu-, where X and Z are variable amino acids; the systematic name "microcystin-XZ" (MC-XZ in short) is then assigned based on the one letter codes (if available; longer codes otherwise) of the amino acids. If the molecule show any other modification, the differences are noted in square brackets before "MC". Of these, several are uncommon non-proteinogenic amino acids:
* D-Masp is D-erythro-β-methyl-isoaspartic acid, a derivative of aspartic acid in β-amino acid form;
* Adda is (all-S,all-E)-3-amino-9-methoxy-2,6,8-trimethyl-10-phenyldeca-4,6-dienoic acid, a β-amino acid exclusively found in microcystin and the related nodularin;
* Mdha is N-methyldehydroalanine, a derivative of dehydroalanine. In nodularin it is replaced by Mdhb (N-methyldehydrobutyrine), another dehydroamino acid derivative. | 1 | Applied and Interdisciplinary Chemistry |
The calcium cycle is a transfer of calcium between dissolved and solid phases. There is a continuous supply of calcium ions into waterways from rocks, organisms, and soils. Calcium ions are consumed and removed from aqueous environments as they react to form insoluble structures such as calcium carbonate and calcium silicate, which can deposit to form sediments or the exoskeletons of organisms. Calcium ions can also be utilized biologically, as calcium is essential to biological functions such as the production of bones and teeth or cellular function. The calcium cycle is a common thread between terrestrial, marine, geological, and biological processes. Calcium moves through these different media as it cycles throughout the Earth. The marine calcium cycle is affected by changing atmospheric carbon dioxide due to ocean acidification. | 1 | Applied and Interdisciplinary Chemistry |
In the recent years, fluid inclusion research has been extensively applied to understand the role of fluids in the deep crust and crust-mantle interface. Fluid inclusions trapped within granulite facies rocks have provided important clues on the petrogenesis of dry granulite facies rocks through the influx of CO-rich fluids from sub-lithospheric sources. CO-rich fluid inclusions were also recorded from a number of ultra high temperature granulite facies terranes, suggesting the involvement of CO in extreme crustal metamorphism. Some recent studies speculate that CO derived by sub-solidus decarbonation reactions during extreme metamorphism has contributed to the deglaciation of the snowball Earth. | 0 | Theoretical and Fundamental Chemistry |
An exact and conscientious worker, Klaproth did much to improve and systematise the processes of analytical chemistry and mineralogy. His appreciation of the value of quantitative methods led him to become one of the earliest adherents of the Lavoisierian doctrines outside France.
Klaproth was the first to discover uranium, identifying it first in torbernite but doing the majority of his research on it with the mineral pitchblende.
On 24 September 1789 he announced his discovery to the Royal Prussian Academy of sciences in Berlin.
He also discovered zirconium in 1789, separating it in the form of its earth zirconia, oxide ZrO2.
Klaproth analyzed a brightly-colored form of the mineral called "hyacinth" from Ceylon. He gave the new element the name zirconium based on its Persian name "zargun", gold-colored.
Klaproth characterised uranium and zirconium as distinct elements, though he did not obtain any of them in the pure metallic state.
Klaproth independently discovered cerium (1803), a rare earth element, around the same time as Jöns Jacob Berzelius and Wilhelm Hisinger, in the winter of 1803.
William Gregor of Cornwall was the first to identify the element titanium in 1791, correctly concluding that he had found a new element in the ore ilmenite from the Menachan valley. He proposed the name "menachanite", but his discovery attracted little attention.
Klaproth verified the presence of an oxide of an unknown element in the ore rutile from Hungary in 1795. Klaproth suggested the name "titanium". It was later determined that menachanite and titanium were the same element, from two different minerals, and Klaproth's name was adopted.
Klaproth clarified the composition of numerous substances until then imperfectly known, including compounds of then newly recognised elements tellurium, strontium and chromium.
Chromium was discovered in 1797 by Louis Nicolas Vauquelin and independently discovered in 1798 by Klaproth and by Tobias Lowitz, in a mineral from the Ural mountains. Klaproth confirmed chromium's independent status as an element.
The existence of tellurium was first suggested in 1783 by Franz-Joseph Mueller von Reichenstein, an Austrian mining engineer who was examining Transylvanian gold samples. Tellurium was also discovered independently by Hungarian Pál Kitaibel in 1789. Mueller sent some of his mineral to Klaproth in 1796. Klaproth isolated the new substance and confirmed the identification of the new element tellurium in 1798. He credited Mueller as its discoverer, and suggested that the heavy metal be named "tellus", Latin for earth.
In 1790 Adair Crawford and William Cruickshank determined that the mineral strontianite, found near Strontian in Scotland, was different from barium-based minerals.
Klaproth was one of several scientists involved in the characterization of strontium compounds and minerals.
Klaproth, Thomas Charles Hope, and
Richard Kirwan independently studied and reported on the properties of strontianite, the preparation of compounds of strontium, and their differentiation from those of barium. In September 1793, Klaproth published on the separation of strontium from barium, and in 1794 on the preparation of strontium oxide and strontium hydroxide.
In 1808, Humphry Davy became the first to successfully isolate the pure element.
Louis Nicolas Vauquelin reported the existence of a new element common to emerald and beryl in 1798, and suggested that it be named "glucine". Klaproth confirmed the presence of a new element, and became involved in a lengthy and ongoing debate over its name by suggesting "beryllia". The element was first isolated in 1828, independently by Friedrich Wöhler and Antoine Bussy. Only in 1949 did IUPAC rule exclusively in favor of the name beryllium.
Klaproth published extensively, collecting over 200 papers by himself in Beiträge zur chemischen Kenntnis der Mineralkörper (5 vols., 1795–1810) and Chemische Abhandlungen gemischten Inhalts (1815). He also published a Chemisches Wörterbuch (1807–1810), and edited a revised edition of F. A. C. Grens Handbuch der Chemie' (1806).
Klaproth became a foreign member of the Royal Society of London in 1795, and a foreign member of the Royal Swedish Academy of Sciences in 1804.
He also belonged to the Institut de France.
The crater Klaproth on the Moon is named after him.
In 1823, botanist Carl Sigismund Kunth published a genus of flowering plants (belonging to the family Loasaceae), from Central America as Klaprothia in his honour.
His son Julius was a famous orientalist. | 1 | Applied and Interdisciplinary Chemistry |
The ShapiroSenapathy algorithm (S&S) is an algorithm for predicting splice junctions in genes of animals and plants. This algorithm has been used to discover disease-causing splice site mutations and cryptic splice sites. | 1 | Applied and Interdisciplinary Chemistry |
Nanofiber Seeding is a process to control the bulk morphology of chemically synthesized conducting polymers.
Typically, catalytic amount of nanofiber seeds are added in prior to onset of nanofiber seeding polymerization (reaction), where seeds are served as the morphology directing agent rather than conventional templates (see hard or soft templating methods). | 0 | Theoretical and Fundamental Chemistry |
For a free ion, e.g. gaseous Ni or Mo, the energy of the d-orbitals are equal in energy; that is, they are "degenerate". In an octahedral complex, this degeneracy is lifted. The energy of the d−y set, which are aimed directly at the ligands are destabilized. On the other hand, the energy of the d, d, and d orbitals, the so-called t set, are stabilized. The labels t and e refer to irreducible representations, which describe the symmetry properties of these orbitals. The energy gap separating these two sets is the basis of crystal field theory and the more comprehensive ligand field theory. The loss of degeneracy upon the formation of an octahedral complex from a free ion is called crystal field splitting or ligand field splitting. The energy gap is labeled Δ, which varies according to the number and nature of the ligands. If the symmetry of the complex is lower than octahedral, the e and t levels can split further. For example, the t and e sets split further in trans-MLL.
Ligand strength has the following order for these electron donors:
:weak: iodine < bromine < fluorine < acetate < oxalate < water < pyridine < cyanide :strong
So called "weak field ligands" give rise to small Δ and absorb light at longer wavelengths. | 0 | Theoretical and Fundamental Chemistry |
Past recipients of the Lilly Award:
*1935 – Willard Myron Allen
*1939 – George Wald
*1941 – David Rittenberg
*1942 – Earl A. Evans, Jr.
*1943 – Herbert E. Carter
*1944 – Joseph S. Fruton
*1946 – John D. Ferry
*1947 – Sidney Colowick
*1948 – Dilworth Wayne Woolley
*1951 – John M. Buchanan
*1953 – Nathan O. Kaplan
*1954 – Harvey A. Itano
*1955 – William F. Neuman
*1956 – Robert A. Alberty
*1957 – Harold A. Scheraga
*1958 – Lester J. Reed
*1959 – Paul Berg
*1960 – James D. Watson
*1962 – Jerard Hurwitz
*1963 – William P. Jencks
*1964 – Bruce N. Ames
*1965 – Gerald M. Edelman
*1966 – Phillips W. Robbins
*1967 – Gordon G. Hammes
*1968 – Charles C. Richardson
*1969 – Mario R. Capecchi
*1970 – Lubert Stryer
*1972 – Bruce M. Alberts
*1974 – James Dahlberg
*1975 – Mark Ptashne
*1976 – Joan A. Steitz
*1977 – Robert G. Roeder
*1978 – Charles R. Cantor
*1979 – Christopher T. Walsh
*1980 – Phillip A. Sharp
*1981 – Roger D. Kornberg
*1982 – Harold M. Weintraub
*1983 – Richard Axel
*1984 – David V. Goeddel
*1985 – Gerald M. Rubin
*1986 – James E. Rothman
*1987 – Jacqueline K. Barton
*1988 – Peter Walter
*1990 – George L. McLendon
*1991 – Peter G. Schultz
*1992 – William DeGrado
*1993 – Stuart L. Schreiber
*1994 – Peter S. Kim
*1995 – Jeremy Berg
*1996 – Gregory L. Verdine
*1997 – Alanna Schepartz
*1998 – John Kuriyan
*1999 – Chaitan Khosla
*2000 – Xiaodong Wang
*2001 – Jennifer Doudna
*2002 – Kevan M. Shokat
*2003 – Andreas Matouschek
*2004 – Benjamin Cravatt III
*2006 – Linda Hsieh-Wilson
*2007 – Anna K. Mapp
*2008 – Paul J. Hergenrother
*2009 – Scott K. Silverman
*2010 – Alice Y. Ting
*2011 – Nathanael Gray
*2012 – Christopher J. Chang
*2016 – Elizabeth Nolan
*2017 – Howard C. Hang
*2018 – Bradley L. Pentelute
*2019 – Neal Devaraj
*2020 – Yimon Aye
*2021 – Jordan L. Meier
*2022 – Lingyin Li
*2023 – Polly Fordyce | 1 | Applied and Interdisciplinary Chemistry |
Naldemedine has a similar chemical structure as naltrexone but with an additional side chain that increases the molecular weight and polar surface area of the substance. Like naloxegol, naldemedine is a substrate of the P-glycoprotein efflux transporter. These properties result in less penetration into the CNS and decrease possible inference with the effects of opioid agonists.
Naldemedine is a dual antagonist for MOR and DOR. Activation of the DOR has been known to cause nausea and/or vomiting, so a dual antagonist can decrease both OIC and nausea/vomiting. | 1 | Applied and Interdisciplinary Chemistry |
A power station, also referred to as a power plant and sometimes generating station or generating plant, is an industrial facility for the generation of electric power. Power stations are generally connected to an electrical grid.
Many power stations contain one or more generators, rotating machine that converts mechanical power into three-phase electric power. The relative motion between a magnetic field and a conductor creates an electric current.
The energy source harnessed to turn the generator varies widely. Most power stations in the world burn fossil fuels such as coal, oil, and natural gas to generate electricity. Low-carbon power sources include nuclear power, and use of renewables such as solar, wind, geothermal, and hydroelectric. | 1 | Applied and Interdisciplinary Chemistry |
After completing his PhD at Purdue University, Atalla was employed at Bell Telephone Laboratories (BTL) in 1949. In 1950, he began working at Bell's New York City operations, where he worked on problems related to the reliability of electromechanical relays, and worked on circuit-switched telephone networks. With the emergence of transistors, Atalla was moved to the Murray Hill lab, where he began leading a small transistor research team in 1956. Despite coming from a mechanical engineering background and having no formal education in physical chemistry, he proved himself to be a quick learner in physical chemistry and semiconductor physics, eventually demonstrating a high level of skill in these fields. He researched, among other things, the surface properties of silicon semiconductors and the use of silica as a protective layer of silicon semiconductor devices. He eventually adopted the alias pseudonyms "Martin" M. Atalla or "John" M. Atalla for his professional career.
Between 1956 and 1960, Atalla led a small team of several BTL researchers, including Eileen Tannenbaum, Edwin Joseph Scheibner and Dawon Kahng. They were new recruits at BTL, like himself, with no senior researchers on the team. Their work was initially not taken seriously by senior management at BTL and its owner AT&T, due to the team consisting of new recruits, and due to the team leader Atalla himself coming from a mechanical engineering background, in contrast to the physicists, physical chemists and mathematicians who were taken more seriously, despite Atalla demonstrating advanced skills in physical chemistry and semiconductor physics.
Despite working mostly on their own, Atalla and his team made significant advances in semiconductor technology. According to Fairchild Semiconductor engineer Chih-Tang Sah, the work of Atalla and his team during 19561960 was "the most important and significant technology advance" in silicon semiconductor technology. | 0 | Theoretical and Fundamental Chemistry |
Beneath the layer of microwells is an ion sensitive layer, below which is an ISFET ion sensor. All layers are contained within a CMOS semiconductor chip, similar to that used in the electronics industry.
Each chip contains an array of microwells with corresponding ISFET detectors.
Each released hydrogen ion then triggers the ISFET ion sensor. The series of electrical pulses transmitted from the chip to a computer is translated into a DNA sequence, with no intermediate signal conversion required. Because nucleotide incorporation events are measured directly by electronics, the use of labeled nucleotides and optical measurements are avoided. Signal processing and DNA assembly can then be carried out in software. | 1 | Applied and Interdisciplinary Chemistry |
The first radio-receptor assay (RRA) was done in 1970 by Lefkowitz et al., using a radiolabeled hormone to determine the binding affinity for its receptor.
A radio-receptor assay requires the separation of the bound from the free ligand. This is done by filtration, centrifugation or dialysis.
A method that does not require separation is the scintillation proximity assay that relies on the fact that β-rays from H travel extremely short distances. The receptors are bound to beads coated with a polyhydroxy scintillator. Only the bound ligands to be detected.
Today, the fluorescence method is preferred to radioactive materials due to a much lower cost, lower hazard, and the possibility of multiplexing the reactions in a high-throughput manner. One problem is that fluorescent-labeled ligands have to bear a bulky fluorophore that may cause it to hinder the ligand binding. Therefore, the fluorophore used, the length of the linker, and its position must be carefully selected.
An example is by using FRET, where the ligand's fluorophore transfers its energy to the fluorophore of an antibody raised against the receptor.
Other detection methods such as surface plasmon resonance do not even require fluorophores. | 1 | Applied and Interdisciplinary Chemistry |
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