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An eluotropic series, which orders solvents by how much they move compounds, can help in selecting a mobile phase. Solvents are also divided into solvent selectivity groups. Using solvents with different elution strengths or different selectivity groups can often give very different results. While single-solvent mobile phases can sometimes give good separation, some cases may require solvent mixtures.
In normal-phase TLC, the most common solvent mixtures include ethyl acetate/hexanes (EtOAc/Hex) for less-polar compounds and methanol/dichloromethane (MeOH/DCM) for more polar compounds. Different solvent mixtures and solvent ratios can help give better separation. In reverse-phase TLC, solvent mixtures are typically water with a less-polar solvent: Typical choices are water with tetrahydrofuran (THF), acetonitrile (ACN), or methanol. | 0 | Theoretical and Fundamental Chemistry |
Source:
If a solid body is modeled by a constant field and the structure of the field is such that it has a penetrable core, then
Here is the position of the dividing surface, is the external force field, simulating a solid, is the field value deep in the solid, , is the Boltzmann constant, and is the temperature.
Introducing "the surface of zero adsorption"
where
and
we get
and the problem of determination is reduced to the calculation of .
Taking into account that for Henry absorption constant we have
where is the number density inside the solid, we arrive at the parametric dependence
where | 0 | Theoretical and Fundamental Chemistry |
Paracelsus, a 16th-century Swiss alchemist, experimented with various opium concoctions, and recommended opium for reducing pain. One of his preparations, a pill which he extolled as his "archanum" or "laudanum", may have contained opium. Paracelsus' laudanum was strikingly different from the standard laudanum of the 17th century and beyond, containing crushed pearls, musk, amber, and other substances. | 1 | Applied and Interdisciplinary Chemistry |
Overall measurements from OCO-3 will help quantify sources and sinks of carbon dioxide from terrestrial ecosystems, the oceans, and from anthropogenic sources. Due to the ISS orbit, measurements will be made at latitudes less than 52°. Data from OCO-3 are expected to significantly improve understanding of global emissions from human activities, for example, using measurements over cities. Near simultaneous observations from other instruments onboard the International Space Station such as ECOSTRESS (measuring plant temperatures) and Global Ecosystem Dynamics Investigation lidar (measuring forest structure) may be combined with OCO-3 observations to help improve the understanding of the terrestrial ecosystem. Similar to OCO-2, OCO-3 will also measure Solar Induced Fluorescence which is a process that occurs during plant photosynthesis. | 1 | Applied and Interdisciplinary Chemistry |
In 2009, HSA was recognized by the Environmental Business Journal with a Technology Merit Award in the category of remediation for the invention of MAGS technology. | 1 | Applied and Interdisciplinary Chemistry |
Respirometry depends on a "what goes in must come out" principle. Consider a closed system first. Imagine that we place a mouse into an air-tight container. The air sealed in the container initially contains the same composition and proportions of gases that were present in the room: 20.95% O, 0.04% CO, water vapor (the exact amount depends on air temperature, see dew point), 78% (approximately) N, 0.93% argon and a variety of trace gases making up the rest (see Earth's atmosphere). As time passes, the mouse in the chamber produces CO and water vapor, but extracts O from the air in proportion to its metabolic demands. Therefore, as long as we know the volume of the system, the difference between the concentrations of O and CO at the start when we sealed the mouse into the chamber (the baseline or reference conditions) compared to the amounts present after the mouse has breathed the air at a later time must be the amounts of CO/O produced/consumed by the mouse. Nitrogen and argon are inert gasses and therefore their fractional amounts are unchanged by the respiration of the mouse. In a closed system, the environment will eventually become hypoxic. | 1 | Applied and Interdisciplinary Chemistry |
Inorganic phosphites (containing ) have been applied to crops to combat fungus-like pathogens of the order oomycetes (water molds). The situation is confusing because of the similarity in name between phosphite and phosphate (a major plant nutrient and fertilizer ingredient), and controversial because phosphites have sometimes been advertised as fertilizers, even though they are converted to phosphate too slowly to serve as a plant's main phosphorus source. In fact, phosphites may cause phytotoxicity when a plant is starved of phosphates. Lemoynie and others have described this complicated situation and noted that calling phosphites fertilizers avoided the regulatory complication and negative public perceptions that might have been incurred by registering them as fungicides.
A major form of inorganic phosphite used in agriculture is monopotassium phosphite. This compound does serve as a potassium fertilizer. | 0 | Theoretical and Fundamental Chemistry |
Tryptophan-rich sensory proteins (TspO) are a family of proteins that are involved in transmembrane signalling. In either prokaryotes or mitochondria they are localized to the outer membrane, and have been shown to bind and transport dicarboxylic tetrapyrrole intermediates of the haem biosynthetic pathway. They are associated with the major outer membrane porins (in prokaryotes) and with the voltage-dependent anion channel (in mitochondria).
TspO of Rhodobacter sphaeroides is involved in signal transduction, functioning as a negative regulator of the expression of some photosynthesis genes (PpsR/AppA repressor/antirepressor regulon). This down-regulation is believed to be in response to oxygen levels. TspO works through (or modulates) the PpsR/AppA system and acts upstream of the site of action of these regulatory proteins. It has been suggested that the TspO regulatory pathway works by regulating the efflux of certain tetrapyrrole intermediates of the haem/bacteriochlorophyll biosynthetic pathways in response to the availability of molecular oxygen, thereby causing the accumulation of a biosynthetic intermediate that serves as a corepressor for the regulated genes. A homologue of the TspO protein in Sinorhizobium meliloti is involved in regulating expression of the ndi locus in response to stress conditions.
In animals, the peripheral benzodiazepine receptor is a mitochondrial protein (located in the outer mitochondrial membrane) characterised by its ability to bind with nanomolar affinity to a variety of benzodiazepine-like drugs, as well as to dicarboxylic tetrapyrrole intermediates of the haem biosynthetic pathway. Depending upon the tissue, it was shown to be involved in steroidogenesis, haem biosynthesis, apoptosis, cell growth and differentiation, mitochondrial respiratory control, and immune and stress response, but the precise function of the PBR remains unclear. The role of PBR in the regulation of cholesterol transport from the outer to the inner mitochondrial membrane, the rate-determining step in steroid biosynthesis, has been studied in detail. PBR is required for the binding, uptake and release, upon ligand activation, of the substrate cholesterol. PBR forms a multimeric complex with the voltage-dependent anion channel (VDAC) and adenine nucleotide carrier. Molecular modeling of PBR suggested that it might function as a channel for cholesterol. Indeed, cholesterol uptake and transport by bacterial cells was induced upon PBR expression. Mutagenesis studies identified a cholesterol recognition/interaction motif (CRAC) in the cytoplasmic C terminus of PBR.
In complementation experiments, rat PBR (pk18) protein functionally substitutes for its homologue TspO in R. sphaeroides, negatively affecting transcription of specific photosynthesis genes. This suggests that PBR may function as an oxygen sensor, transducing an oxygen-triggered signal leading to an adaptive cellular response.
These observations suggest that fundamental aspects of this receptor and the downstream signal transduction pathway are conserved in bacteria and higher eukaryotic mitochondria. The alpha-3 subdivision of the purple bacteria is considered to be a likely source of the endosymbiont that ultimately gave rise to the mitochondrion. Therefore, it is possible that the mammalian PBR remains both evolutionarily and functionally related to the TspO of R. sphaeroides. | 1 | Applied and Interdisciplinary Chemistry |
In inorganic chemistry, mineral hydration is a reaction which adds water to the crystal structure of a mineral, usually creating a new mineral, commonly called a hydrate.
In geological terms, the process of mineral hydration is known as retrograde alteration and is a process occurring in retrograde metamorphism. It commonly accompanies metasomatism and is often a feature of wall rock alteration around ore bodies. Hydration of minerals occurs generally in concert with hydrothermal circulation which may be driven by tectonic or igneous activity. | 0 | Theoretical and Fundamental Chemistry |
ASBMB gives out an array of annual awards in different categories.
* Lemberg Medal - after 5 years' membership for significant contribution
* Shimadzu Research Medal - within 15 years post-PhD graduation
* Eppendorf Edman ECR Award - within 7 years post-PhD
* SDR Scientific Education Award - education (especially innovation and creativity)
* Boomerang Award - for expatriate Australians to return to present at the ASBMB conference and seminars at universities/institutes.
The society also awards fellowships to researchers within 2 years post-PhD. | 1 | Applied and Interdisciplinary Chemistry |
The tripartite motif is always present at the N-terminus of the TRIM proteins. The TRIM motif includes the following three domains:
* (1) a RING finger domain
* (2) one or two B-box zinc finger domains
** when only one B-box is present, it is always a type-2 B-box
** when two B-boxes are present the type-1 B-Box always precedes the type-2 B-Box
* (3) coiled coil region
The C-terminus of TRIM proteins contain either:
* Group 1 proteins: a C-terminal domain selected from the following list:
** NHL and IGFLMN domains, either in association or alone
** PHD domain associated with a bromodomain
** MATH domain (in e.g., TRIM37)
** ARF domain (in e.g., TRIM23)
** EXOIII domain (in e.g., TRIM19) or
* Group 2 proteins: a SPRY C-terminal domain
**e.g. TRIM21 | 1 | Applied and Interdisciplinary Chemistry |
STAT4 binds to hundreds of sites in the genome, among others to the promoters of genes for cytokines (IFN-γ, TNF), receptors (IL18R1, IL12rβ2, IL18RAP), and signaling factors (MYD88). | 1 | Applied and Interdisciplinary Chemistry |
The transition to the Late Bronze Age brought societal change to the British Isles, and also apparently increased availability of gold, which led to a trend to much larger and more massive pieces. The largest were jewellery worn round the neck in a range of styles, the most ostentatious wide flat collars or gorgets with ribbed decoration following the shape of the piece, and round discs at the side. The Mold Cape is unique among survivals, but fits in with the trend to massive pieces emphasizing the neck and chest. It was clearly not for prolonged wear, as the wearer could not raise their arms. In Ireland, lunulae were probably replaced as neck ornaments firstly by gold torcs, found from the Irish Middle Bronze Age, and then in the Late Bronze Age by the spectacular "gorgets" of thin ribbed gold, some with round discs at the side, of which 9 examples survive, 7 in the National Museum of Ireland.
Designs based on twisted bars or ribbons giving a spiral became popular, probably influenced by the Continent. "Although over 110 identifiable British [includes Ireland] ribbon torcs are known, the dating of these simple, flexible ornaments is elusive", perhaps indicating "a long-lived preference for ribbon torcs, which continued for over 1,000 years", into the Iron Age. | 1 | Applied and Interdisciplinary Chemistry |
* Encyclopædia Britannica, 14th ed.
* J. Day & R. F. Tylecote (eds.), The Industrial Revolution in Metals (1991)
* P. W. King, "The Cupola at Bristol", Somerset Araeology and Natural History 140 (for 1997), 37–52
* P. W. King, "Sir Clement Clerke and the Adoption of coal in metallurgy", Transactions of the Newcomen Society 73(1) (2001–2), 33–53 | 1 | Applied and Interdisciplinary Chemistry |
There are many Next Generation Sequencing sequencing platforms available, postdating classical Sanger sequencing methodologies. Other platforms include Roche 454 sequencer and Life Technologies SOLiD systems, the Life Technologies Ion Torrent and Illuminas Illumina Genome Analyzer II (defunct) and subsequent Illumina MiSeq, HiSeq, and NovaSeq series instruments, all of which can be used for massively parallel exome sequencing. These short read' NGS systems are particularly well suited to analyse many relatively short stretches of DNA sequence, as found in human exons. | 1 | Applied and Interdisciplinary Chemistry |
The most common and most important cryptand is ; the systematic IUPAC name for this compound is 1,10-diaza-4,7,13,16,21,24-hexaoxabicyclo[8.8.8]hexacosane. This compound is termed [[2.2.2-Cryptand|[2.2.2]cryptand]], where the numbers indicate the number of ether oxygen atoms (and hence binding sites) in each of the three bridges between the amine nitrogen caps. Many cryptands are commercially available under the tradename Kryptofix. All-amine cryptands exhibit particularly high affinity for alkali metal cations, which has allowed the isolation of salts of K. | 0 | Theoretical and Fundamental Chemistry |
Because it is so readily made by heating limestone, lime must have been known from the earliest times, and all the early civilizations used it in building mortars and as a stabilizer in mud renders and floors. According to finds at 'Ain Ghazal in Jordan, Yiftahel in Israel, and Abu Hureyra in Syria dating to 7500–6000 BCE, the earliest use of lime was mostly as a binder on floors and in plaster for coating walls. This use of plaster may in turn have led to the development of proto-pottery, made from lime and ash. In mortar, the oldest binder was mud. According to finds at Catal Hüyük in Turkey, mud was soon followed by clay, and then by lime in the 6th millennium BCE. | 1 | Applied and Interdisciplinary Chemistry |
-Photo-leucine resembles -leucine in its structure. However, the latter contains a photo-activatable diazirine ring, which the former does not, and which yields a reactive carbene after the light-induced loss of nitrogen, fact that confers -photo-leucine its properties. This photo-reactive amino acid is synthesized by α-bromination of the azi-carboxylic acid followed by aminolysis of azi-bromo-carboxylic acid.
The classic procedure for synthesizing photo-leucine is based on the following steps:
*4,4-azi-pentanoic acid, CCl and thionyl chloride are heated to 65 °C for 30 minutes. Then, N-bromosuccinimide, CCl and 48% HBr are added and the mixture is stirred at 55 °C for 4 hours. The solvent and free bromine are removed under reduced pressure and the residue is extracted with 50 mL CCl. The solvent is removed and the crude product (2-bromo-4,4-azi-pentanoyl chloride) dissolved in acetone and hydrolyzed with aqueous NaHCO. The crude brominated free acid is obtained upon acidification with HCl and extraction with dichloromethane. The solvent is removed and the product filtered through silica gel in isohexane acetate followed by the removal of the solvent. Following this procedure, we are able to add a diazirine ring to the 4,4-azi-pentanoic acid, and to obtain finally the -2-bromo-4,4-azi-pentanoic acid.
*Aminolysis of -2-bromo-4,4-azi-pentanoic acid is performed in ammonia-saturated methanol and 25% aq ammonia for 5 days at 55 °C. After evaporation of the ammonia, 20 mL of concentrated HCl are added followed by evaporation of the water at reduced pressure. The dry residue is extracted with 20 mL hot methanol and the extract neutralized with N,N-dimetylethylamine. Upon standing for 2 days at -32 °C a precipitate formed which is isolated and re-crystallized twice from 70% ethanol to yield pure -2-amino-4,4-azi-pentonoic acid.
*-2-amino-4,4-azi-pentonoic acid is acetylated to obtain acetylation -2-acetamino-4,4-azi-pentanoic acid followed by enzymatic deacetylation to give pure -2-amino-4,4'-azi-pentanoic acid, also known as -photo-leucine.
Recently, synthesis of photo-leucine has been improved. This new way of synthesizing photo-leucine requires boc-(S)-photo-leucine, which is prepared via ozonolysis of a commercially available product, followed by formation of the diazirine by de method of Church and Weiss.
This route supposes a significant improvement over the original six-step synthesis of (S)-photo-leucine, which proceeded in low yield and required enzymatic resolution of a racemic intermediate. | 0 | Theoretical and Fundamental Chemistry |
Cold hardening is the physiological and biochemical process by which an organism prepares for cold weather. | 1 | Applied and Interdisciplinary Chemistry |
To recognize individuals and groups in a number of areas, WEF sponsors awards in the categories of: Published Papers; Operational and Design Excellence; Education; Individual Service and Contribution; Fellows; Organization and Association Recognition; National Municipal Stormwater and Green Infrastructure, as well as Committee Chair Service Appreciation. | 1 | Applied and Interdisciplinary Chemistry |
Above the liquidus temperature, the material is homogeneous and liquid at equilibrium. As the system is cooled below the liquidus temperature, more and more crystals will form in the melt if one waits a sufficiently long time, depending on the material. Alternately, homogeneous glasses can be obtained through sufficiently fast cooling, i.e., through kinetic inhibition of the crystallization process.
The crystal phase that crystallizes first on cooling a substance to its liquidus temperature is termed primary crystalline phase or primary phase. The composition range within which the primary phase remains constant is known as primary crystalline phase field.
The liquidus temperature is important in the glass industry because crystallization can cause severe problems during the glass melting and forming processes, and it also may lead to product failure. | 0 | Theoretical and Fundamental Chemistry |
Before 1800 A.D., the iron and steel industry was located where raw material, power supply and running water were easily available. After 1950, the iron and steel industry began to be located on large areas of flat land near sea ports. The history of the modern steel industry began in the late 1850s. Since then, steel has become a staple of the worlds industrial economy. This article is intended only to address the business, economic and social dimensions of the industry, since the bulk production of steel began as a result of Henry Bessemers development of the Bessemer converter, in 1857. Previously, steel was very expensive to produce, and was only used in small, expensive items, such as knives, swords and armor. | 1 | Applied and Interdisciplinary Chemistry |
The test method involves variables limiting reproducibility. Tests normally show observations varying plus or minus ten to twenty percent around the mean. | 0 | Theoretical and Fundamental Chemistry |
Trimethylsilyl chloride is used to prepare other trimethylsilyl halides and pseudohalides, including trimethylsilyl fluoride, trimethylsilyl bromide, trimethylsilyl iodide, trimethylsilyl cyanide, trimethylsilyl azide, and trimethylsilyl trifluoromethanesulfonate (TMSOTf). These compounds are produced by a salt metathesis reaction between trimethylsilyl chloride and a salt of the (pseudo)halide (MX):
TMSCl, lithium, and nitrogen molecule react to give tris(trimethylsilyl)amine, under catalysis by nichrome wire or chromium trichloride:
Using this approach, atmospheric nitrogen can be introduced into organic substrate. For example, tris(trimethylsilyl)amine reacts with α,δ,ω-triketones to give tricyclic pyrroles.
Reduction of trimethylsilyl chloride give hexamethyldisilane: | 0 | Theoretical and Fundamental Chemistry |
adopts three structures, depending on the temperature and the state (solid, liquid, gas). Solid has a sheet-like layered structure with cubic close-packed chloride ions. In this framework, the Al centres exhibit octahedral coordination geometry. Yttrium(III) chloride adopts the same structure, as do a range of other compounds. When aluminium trichloride is in its melted state, it exists as the dimer , with tetracoordinate aluminium. This change in structure is related to the lower density of the liquid phase (1.78 g/cm) versus solid aluminium trichloride (2.48 g/cm). dimers are also found in the vapour phase. At higher temperatures, the dimers dissociate into trigonal planar monomer, which is structurally analogous to boron trifluoride|. The melt conducts electricity poorly, unlike more ionic halides such as sodium chloride.
Aluminium chloride monomer belongs to the point group D in its monomeric form and D in its dimeric form. | 0 | Theoretical and Fundamental Chemistry |
The number of entities (symbol N) in a one-mole sample equals the Avogadro number (symbol N), a dimensionless quantity.
Historically, N approximates the number of nucleons (protons or neutrons) in one gram of ordinary matter.
The Avogadro constant (symbol ) has numerical multiplier given by the Avogadro number with the unit reciprocal mole (mol).
The ratio is a measure of the amount of substance (with the unit mole). | 0 | Theoretical and Fundamental Chemistry |
Levofloxacin and later generation fluoroquinolones are collectively referred to as "respiratory quinolones" to distinguish them from earlier fluoroquinolones which exhibited modest activity toward the important respiratory pathogen Streptococcus pneumoniae.
The drug exhibits enhanced activity against the important respiratory pathogen Streptococcus pneumoniae relative to earlier fluoroquinolone derivatives like ciprofloxacin. For this reason, it is considered a "respiratory fluoroquinolone" along with more recently developed fluoroquinolones such as moxifloxacin and gemifloxacin. It is less active than ciprofloxacin against Gram-negative bacteria, especially Pseudomonas aeruginosa, and lacks the anti-methicillin-resistant Staphylococcus aureus (MRSA) activity of moxifloxacin and gemifloxacin. Levofloxacin has shown moderate activity against anaerobes, and is about twice as potent as ofloxacin against Mycobacterium tuberculosis and other mycobacteria, including Mycobacterium avium complex.
Its spectrum of activity includes most strains of bacterial pathogens responsible for respiratory, urinary tract, gastrointestinal, and abdominal infections, including Gram negative (Escherichia coli, Haemophilus influenzae, Klebsiella pneumoniae, Legionella pneumophila, Moraxella catarrhalis, Proteus mirabilis, and Pseudomonas aeruginosa), Gram positive (methicillin-sensitive but not methicillin-resistant Staphylococcus aureus, Streptococcus pneumoniae, Staphylococcus epidermidis, Enterococcus faecalis, and Streptococcus pyogenes), and atypical bacterial pathogens (Chlamydophila pneumoniae and Mycoplasma pneumoniae). Compared to earlier antibiotics of the fluoroquinoline class such as ciprofloxacin, levofloxacin exhibits greater activity towards Gram-positive bacteria but lesser activity toward Gram-negative bacteria, especially Pseudomonas aeruginosa. | 0 | Theoretical and Fundamental Chemistry |
Phillips started his academic career as an assistant professor at the University of Illinois Urbana-Champaign, followed by his appointment as a professor of biochemistry at Rice University in 1987. In 1993, he assumed the position of Rice Scientia Lecturer, subsequently receiving the Robert A. Welch Lecturer appointment in 2001. He joined the University of Wisconsin-Madison in 2000 as a professor of Biochemistry and took on the role of professor emeritus in 2012. He has been serving as a professor of chemistry, as well as the Ralph and Dorothy Looney Professor of Biochemistry and Cell Biology at Rice University. | 1 | Applied and Interdisciplinary Chemistry |
Absolute electrode potential, in electrochemistry, according to an IUPAC definition, is the electrode potential of a metal measured with respect to a universal reference system (without any additional metal–solution interface). | 0 | Theoretical and Fundamental Chemistry |
* A Tentative Theory of Metallic Whisker Growth University of Illinois Urbana-Champaign, Received 4 June 1953 The American Physical Society
* Collected Works of J. D. Eshelby, Mechanics of Defects and Inhomogeneities, Springer (2006), Xanthippi Markenscoff and Anurag Gupta (Eds.)
* J. D. Eshelby, "The continuum theory of lattice defects," in: F. Seitz and D. Turnbull (eds.), Progress in Solid State Physics, Vol. 3, Academic Press, New York (1956), pp. 79–303. | 1 | Applied and Interdisciplinary Chemistry |
Hyperglycemia, a side effect caused by diabetes, combines with oxidative stress to create advanced glycation end-products (AGEs) that can lead to diabetic retinopathy (RD) and cause symptoms such as blindness in adults.
The manipulation of the glyoxalase system in mice retina has shown there is a potential for targeting the glyoxalase system to use as a therapeutic treatment for RD by lowering the production of AGEs.
Oxidative stress can lead to worsening neurological diseases such as Alzheimers, Parkinsons, and Autism Spectrum Disorder. Flavonoids, a type of antioxidant that combats oxidative stress in the body, has been found to help decrease the production of radical oxygen species (ROS) mostly by preventing the formation of free radicals but also partially by promoting the glyoxalase pathway via increasing transcription of GSH and GSH constituent subunits to increase intracellular levels of GSH. | 1 | Applied and Interdisciplinary Chemistry |
CKLF-like MARVEL transmembrane domain-containing protein 2 (i.e. CMTM2), previously termed chemokine-like factor superfamily 2 ( i.e. CKLFSF2), is a member of the CKLF-like MARVEL transmembrane domain-containing family (CMTM) of proteins. In humans, it is encoded by the CMTM2 gene located in band 22 on the long (i.e. "q") arm of chromosome 16. CMTM2 protein is expressed in the bone marrow and various circulating blood cells. It is also highly expressed in testicular tissues: The CMTM2 gene and CMTM2 protein, it is suggested, may play an important role in testicular development.
Studies find that the levels of CMTM2 protein in hepatocellular carcinoma tissues of patients are lower higher than their levels in normal liver tissues. CMTM2 protein levels were also lower in the hepatocellular carcinoma tissues that had a more aggressive pathology and therefore a possible poorer prognosis. Finally, the forced overexpression of CMTM2 protein in cultured hepatocellular tumor cells inhibited their invasiveness and migration. These findings suggest that CMTM2 protein suppresses the development and/or progression of hepatocellular carcinoma and therefore that the CMTM2 gene acts as a tumor suppressor in this cancer. Patients with higher CMTM2 levels in their linitis plastica stomach cancer (i.e. a type of gastric cancer also termed diffuse-type gastric cancer or diffuse type adenocarcinoma of the stomach) tissues had better prognoses than patients with lower CMTM2 levels in their linitis plastica tissues. And, the CMTM2 gene has been found to be more highly expressed in the salivary gland adenoid cystic carcinoma tissues of patients who did not develop tumor recurrences or perineural invasion of their carcinomas compared to the expression of this gene in patients whose adenoid cystic carcinoma tissues went on to develop these complications. These findings suggest that the CMTM2 gene may act as a tumor suppressor not only in hepatocellular carcinoma but also in linitis plastica and salivary gland adenoid cystic carcinoma. Further studies are needed to confirm these findings and determine if CMTM2 protein can serve as a marker for the severity of these three cancers and/or as a therapeutic target for treating them. | 1 | Applied and Interdisciplinary Chemistry |
Nilutamide is a nitroaromatic hydantoin analog of flutamide, as seen in figure 5. Nilutamide is eliminated exclusively by metabolism, mainly by reduction of the aromatic nitro group. Although the hydrolysis of one of the carbonyl functions of the imidazolinedione was identified, it is much less susceptible to hepatic metabolism than the amide bond in hydroxuflutamide. This results in a longer half-life of nilutamide in humans of 2 days. Nevertheless, the nitro anion-free radical formed during nitro reduction could still be associated with hepatotoxicity in humans, especially when using relatively high dosage employed for androgen blockage. Nilutamide causes side-effects which limit its usage, such as pneumonitis and delayed adaption to darkness. | 1 | Applied and Interdisciplinary Chemistry |
The final step regards analysis of data and storage: after obtaining the sequencing reads, UMI and index sequences are automatically removed from the reads and their quality is analyzed by PHRED (software able to evaluate the quality of the sequencing process); reads can then be mapped or aligned to a reference genome in order to extract information about their similarity: reads having the same length, sequence and UMI are considered as equal and are removed from the hit list. Indeed, the number of different UMIs for a given small RNA sequence reflects its copy number.
The small RNAs are finally quantified by assigning molecules to transcript annotations from different databases (Mirbase, GtRNAdb and Gencode). | 1 | Applied and Interdisciplinary Chemistry |
The protein is 273 amino acids in length with the first 23 residues acting as a signal peptide which is subsequently cleaved. It has a Uniprot accession of [https://www.uniprot.org/uniprot/P02872 P02872]. There are over 20 structures of this protein in the PDB which reveal and all beta-sheet protein with a tetrameric quaternary structure. It is a member of the Lectin_legB PFAM family.
[http://www.ebi.ac.uk/pdbe/searchResults.html?display=both&term=P02872 Available Structures of peanut agglutinin] | 1 | Applied and Interdisciplinary Chemistry |
Singled-layered systems of this type are drained by a multi-layer fabric mat called a “drainage mat” that combines soil separation, drainage, and protection functions. Current research suggests that the depth of the soil media, material, and number of layers affect the success rate of an individual green or SCV roof. | 1 | Applied and Interdisciplinary Chemistry |
The ammonia fixed as part of the glutamate dehydrogenase enzyme reaction in the neurons is transaminated into α-ketoisocaproate to form the branched-chain amino acid leucine, which is exported to the astrocytes, where the process is reversed. α-ketoisocaproate is transported in the other direction. | 1 | Applied and Interdisciplinary Chemistry |
In a multistep reaction, the rate-determining step does not necessarily correspond to the highest Gibbs energy on the reaction coordinate diagram. If there is a reaction intermediate whose energy is lower than the initial reactants, then the activation energy needed to pass through any subsequent transition state depends on the Gibbs energy of that state relative to the lower-energy intermediate. The rate-determining step is then the step with the largest Gibbs energy difference relative either to the starting material or to any previous intermediate on the diagram.
Also, for reaction steps that are not first-order, concentration terms must be considered in choosing the rate-determining step. | 0 | Theoretical and Fundamental Chemistry |
From the structural perspective, haloalkanes can be classified according to the connectivity of the carbon atom to which the halogen is attached. In primary (1°) haloalkanes, the carbon that carries the halogen atom is only attached to one other alkyl group. An example is chloroethane (). In secondary (2°) haloalkanes, the carbon that carries the halogen atom has two C–C bonds. In tertiary (3°) haloalkanes, the carbon that carries the halogen atom has three C–C bonds.
Haloalkanes can also be classified according to the type of halogen on group 17 responding to a specific halogenoalkane. Haloalkanes containing carbon bonded to fluorine, chlorine, bromine, and iodine results in organofluorine, organochlorine, organobromine and organoiodine compounds, respectively. Compounds containing more than one kind of halogen are also possible. Several classes of widely used haloalkanes are classified in this way chlorofluorocarbons (CFCs), hydrochlorofluorocarbons (HCFCs) and hydrofluorocarbons (HFCs). These abbreviations are particularly common in discussions of the environmental impact of haloalkanes. | 0 | Theoretical and Fundamental Chemistry |
Railways commonly used salt water load banks in the 1950s to test the output power of diesel-electric locomotives. They were subsequently replaced by specially designed resistive load banks. Some early three-phase AC electric locomotives also used liquid rheostats for starting up the motors and balancing load between multiple locomotives.
Liquid rheostats were sometimes used in large (thousands of kilowatts/horsepower) wound rotor motor drives, to control the rotor circuit resistance and so the speed of the motor. Electrode position could be adjusted with a small electrically operated winch or a pneumatic cylinder. A cooling pump and heat exchanger were provided to allow slip energy to be dissipated into process water or other water system.
Massive rheostats were once used for dimming theatrical lighting, but solid-state components have taken their place in most high-wattage applications. | 0 | Theoretical and Fundamental Chemistry |
Antimonide bromides or bromide antimonides are compounds containing anions composed of bromide (Br) and antimonide (Sb). They can be considered as mixed anion compounds. They are in the category of pnictidehalides. Related compounds include the antimonide chlorides, antimonide iodides, arsenide chlorides, arsenide bromides, arsenide iodides, phosphide chlorides, phosphide bromides, and phosphide iodides. The bromoantimonates have antimony in positive oxidation states.
The antimony can be linked into chains, in which case it has a formal oxidation state of −1. Alternately it can be in pairs as Sb, with an oxidation state of −2 for each atom.
Many of these compounds are clathrates, whereby there are two interpenetrating structures that are only weakly bound to each other by van der Waals force. | 0 | Theoretical and Fundamental Chemistry |
The universal expansion joint can absorb not only axial movements but angular and lateral movements as well. It consists of two metal bellows with an intermediate pipe and connectors on both sides. As a special form of the axial expansion joint, the universal expansion joint has only a limited pressure resistance for stability reasons and, moreover, loads the adjacent pipe supports with the axial compressive force resulting from the internal pressure. It is usually used to compensate large axial and lateral movements at low pressure. | 1 | Applied and Interdisciplinary Chemistry |
The C standard provides a convenient unit (the dalton) in which to express nuclear mass for defining the mass excess. However, its usefulness arises in the calculation of nuclear reaction kinematics or decay. Only a small fraction of the total energy that is associated with an atomic nucleus by mass–energy equivalence, on the order of 0.01% to 0.1% of the total mass, may be absorbed or liberated as radiation. By working in terms of the mass excess, much of the mass changes which arise from the transfer or release of nucleons is effectively removed, highlighting the net energy difference.
Nuclear reaction kinematics are customarily performed in units involving the electronvolt, which derives from accelerator technology. The combination of this practical point with the theoretical relation makes the unit megaelectronvolt over the speed of light squared (MeV/c) a convenient form in which to express nuclear mass. However, the numerical values of nuclear masses in MeV/c are quite large (even the proton mass is ~938.27 MeV/c), while mass excesses range in the tens of MeV/c. This makes tabulated mass excess less cumbersome for use in calculations. The 1/c factor is typically omitted when quoting mass excess values in MeV, since the interest is more often energy and not mass; if one wanted units of mass, one would simply change the units from MeV to MeV/c without altering the numerical value. | 0 | Theoretical and Fundamental Chemistry |
The labeled [F]FDG compound has a relatively short shelf life which is dominated by the physical decay of fluorine-18 with a half-life of 109.8 minutes, or slightly less than two hours. Still, this half life is sufficiently long to allow shipping the compound to remote PET scanning facilities, in contrast to other medical radioisotopes like carbon-11. Due to transport regulations for radioactive compounds, delivery is normally done by specially licensed road transport, but means of transport may also include dedicated small commercial jet services. Transport by air allows to expand the distribution area around a [F]FDG production site to deliver the compound to PET scanning centres even hundreds of miles away.
Recently, on-site cyclotrons with integral shielding and portable chemistry stations for making [F]FDG have accompanied PET scanners to remote hospitals. This technology holds some promise in the future, for replacing some of the scramble to transport [F]FDG from site of manufacture to site of use. | 1 | Applied and Interdisciplinary Chemistry |
In marine and freshwater ecology, a particle is a small object. Particles can remain in suspension in the ocean or freshwater. However, they eventually settle (rate determined by Stokes' law) and accumulate as sediment. Some can enter the atmosphere through wave action where they can act as cloud condensation nuclei (CCN). Many organisms filter particles out of the water with unique filtration mechanisms (filter feeders). Particles are often associated with high loads of toxins which attach to the surface. As these toxins are passed up the food chain they accumulate in fatty tissue and become increasingly concentrated in predators (see bioaccumulation). Very little is known about the dynamics of particles, especially when they are re-suspended by dredging. They can remain floating in the water and drift over long distances. The decomposition of some particles by bacteria consumes much oxygen and can cause the water to become hypoxic. | 1 | Applied and Interdisciplinary Chemistry |
Oseen considered the sphere to be stationary and the fluid to be flowing with a flow velocity () at an infinite distance from the sphere. Inertial terms were neglected in Stokes' calculations. It is a limiting solution when the Reynolds number tends to zero. When the Reynolds number is small and finite, such as 0.1, correction for the inertial term is needed. Oseen substituted the following flow velocity values into the Navier-Stokes equations.
Inserting these into the Navier-Stokes equations and neglecting the quadratic terms in the primed quantities leads to the derivation of Oseen's approximation:
Since the motion is symmetric with respect to axis and the divergence of the vorticity vector is always zero we get:
the function can be eliminated by adding to a suitable function in , is the vorticity function, and the previous function can be written as:
and by some integration the solution for is:
thus by letting be the "privileged direction" it produces:
then by applying the three boundary conditions we obtain
the new improved drag coefficient now become:
and finally, when Stokes solution was solved on the basis of Oseens approximation, it showed that the resultant drag force is given by
where:
* is the Reynolds number based on the radius of the sphere,
* is the hydrodynamic force
* is the flow velocity
* is the fluid viscosity
The force from Oseen's equation differs from that of Stokes by a factor of | 1 | Applied and Interdisciplinary Chemistry |
Secondary clarifiers following RBCs are identical in design to conventional humus tanks, as used downstream of trickling filters. Sludge is generally removed daily, or pumped automatically to the primary settlement tank for co-settlement. Regular sludge removal reduces the risk of anaerobic conditions from developing within the sludge, with subsequent sludge flotation due to the release of gases. | 1 | Applied and Interdisciplinary Chemistry |
The term nucleic acid is the overall name for DNA and RNA, members of a family of biopolymers, and is synonymous with polynucleotide. Nucleic acids were named for their initial discovery within the nucleus, and for the presence of phosphate groups (related to phosphoric acid). Although first discovered within the nucleus of eukaryotic cells, nucleic acids are now known to be found in all life forms including within bacteria, archaea, mitochondria, chloroplasts, and viruses (There is debate as to whether viruses are living or non-living). All living cells contain both DNA and RNA (except some cells such as mature red blood cells), while viruses contain either DNA or RNA, but usually not both.
The basic component of biological nucleic acids is the nucleotide, each of which contains a pentose sugar (ribose or deoxyribose), a phosphate group, and a nucleobase.
Nucleic acids are also generated within the laboratory, through the use of enzymes (DNA and RNA polymerases) and by solid-phase chemical synthesis. | 1 | Applied and Interdisciplinary Chemistry |
The first part of the reaction mechanism consists of an ordinary nucleophilic aliphatic substitution to produce a gem-halohydrin:
: RCH(Cl) + KOH RCH(OH)Cl + KCl
The remaining halide is a good leaving group and this enables the newly created hydroxy group to convert into a carbonyl group by expelling the halide:
:RCH(OH)Cl Rearrangement gives R-CHO + HCl | 0 | Theoretical and Fundamental Chemistry |
Ethanol fermentation produces unharvested byproducts such as heat, carbon dioxide, food for livestock, water, methanol, fuels, fertilizer and alcohols. The cereal unfermented solid residues from the fermentation process, which can be used as livestock feed or in the production of biogas, are referred to as Distillers grains and sold as WDG, Wet Distillers grains, and DDGS, Dried Distillers Grains with Solubles, respectively. | 1 | Applied and Interdisciplinary Chemistry |
Classical thermodynamics considers three main kinds of thermodynamic processes: (1) changes in a system, (2) cycles in a system, and (3) flow processes.
(1) A Thermodynamic process is a process in which the thermodynamic state of a system is changed. A change in a system is defined by a passage from an initial to a final state of thermodynamic equilibrium. In classical thermodynamics, the actual course of the process is not the primary concern, and often is ignored. A state of thermodynamic equilibrium endures unchangingly unless it is interrupted by a thermodynamic operation that initiates a thermodynamic process. The equilibrium states are each respectively fully specified by a suitable set of thermodynamic state variables, that depend only on the current state of the system, not on the path taken by the processes that produce the state. In general, during the actual course of a thermodynamic process, the system may pass through physical states which are not describable as thermodynamic states, because they are far from internal thermodynamic equilibrium. Non-equilibrium thermodynamics, however, considers processes in which the states of the system are close to thermodynamic equilibrium, and aims to describe the continuous passage along the path, at definite rates of progress.
As a useful theoretical but not actually physically realizable limiting case, a process may be imagined to take place practically infinitely slowly or smoothly enough to allow it to be described by a continuous path of equilibrium thermodynamic states, when it is called a "quasi-static" process. This is a theoretical exercise in differential geometry, as opposed to a description of an actually possible physical process; in this idealized case, the calculation may be exact.
A really possible or actual thermodynamic process, considered closely, involves friction. This contrasts with theoretically idealized, imagined, or limiting, but not actually possible, quasi-static processes which may occur with a theoretical slowness that avoids friction. It also contrasts with idealized frictionless processes in the surroundings, which may be thought of as including purely mechanical systems; this difference comes close to defining a thermodynamic process.
(2) A cyclic process carries the system through a cycle of stages, starting and being completed in some particular state. The descriptions of the staged states of the system are not the primary concern. The primary concern is the sums of matter and energy inputs and outputs to the cycle. Cyclic processes were important conceptual devices in the early days of thermodynamical investigation, while the concept of the thermodynamic state variable was being developed.
(3) Defined by flows through a system, a flow process is a steady state of flows into and out of a vessel with definite wall properties. The internal state of the vessel contents is not the primary concern. The quantities of primary concern describe the states of the inflow and the outflow materials, and, on the side, the transfers of heat, work, and kinetic and potential energies for the vessel. Flow processes are of interest in engineering. | 0 | Theoretical and Fundamental Chemistry |
The mass concentration is defined as the mass of a constituent divided by the volume of the mixture :
The SI unit is kg/m (equal to g/L). | 0 | Theoretical and Fundamental Chemistry |
Nanoparticles of pure metals, oxides, carbides, and nitrides, can be created by vaporizing a solid precursor with a thermal plasma and then condensing the vapor by expansion or quenching in a suitable gas or liquid. The plasma can be produced by dc jet, electric arc, or radio frequency (RF) induction. The thermal plasma can reach temperatures of 10.000 K and can thus also synthesize nanopowders with very high boiling points. Metal wires can be vaporized by the exploding wire method.
In RF induction plasma torches, energy coupling to the plasma is accomplished through the electromagnetic field generated by the induction coil. The plasma gas does not come in contact with electrodes, thus eliminating possible sources of contamination and allowing the operation of such plasma torches with a wide range of gases including inert, reducing, oxidizing, and other corrosive atmospheres. The working frequency is typically between 200 kHz and 40 MHz. Laboratory units run at power levels in the order of 30–50 kW, whereas the large-scale industrial units have been tested at power levels up to 1 MW. As the residence time of the injected feed droplets in the plasma is very short, it is important that the droplet sizes are small enough in order to obtain complete evaporation. | 0 | Theoretical and Fundamental Chemistry |
The Nyāya school of Hinduism developed and refined many treatises on epistemology that widely influenced other schools of Hinduism. Nyāya treated it as theory of knowledge, and its scholars developed it as Pramana-sastras. Pramana, a Sanskrit word, literally is "means of knowledge". It encompasses one or more reliable and valid means by which human beings gain accurate, true knowledge. The focus of Pramana is how correct knowledge can be acquired, how one knows, how one doesn't, and to what extent knowledge pertinent about someone or something can be acquired.
The Naiyayikas (the Nyāya scholars) accepted four valid means (pramaṇa) of obtaining valid knowledge (pramana) – perception (pratyakṣa), inference (anumāna), comparison (upamāna) and word/testimony of reliable sources (śabda). The Nyāya scholars, along with those from other schools of Hinduism, also developed a theory of error, to methodically establish means to identify errors and the process by which errors are made in human pursuit of knowledge. These include Saṁśaya (समस्या, problems, inconsistencies, doubts) and Viparyaya (विपर्यय, contrariness, errors) which can be corrected or resolved by a systematic process of Tarka (तर्क, reasoning, technique). | 1 | Applied and Interdisciplinary Chemistry |
Around 1750, colonial raw materials poured into the British Isles, and factories began to appear. The earlier hardware with its chiseled and filed details fast gave way to less expensive, but equally functional hardware of similar but unadorned design. H and HL hinges are a good example of this transition.
After the American Revolution machines were invented to make screws and to produce rolled iron in thin sheets. By about 1800 cheap screws were readily available. Cast iron technology had long been available – now machine-made screws allowed such hardware to be economically mounted. Butt type hinges can be seen during this "Federal" Period (1800–1830) – but they quickly fell from favor, probably because they were subject to breakage.
A more obvious change in the shutter hardware was noted in shutter bolts. The common slide plate and keeper style of bolt started to appear. It was simpler to fabricate and operate than the earlier "strap style lock". This bolt relied on both the new cheap fasteners and the readily available plate iron. This bolt also relied on machines and "dies." This form of shutter bolt has been made continually ever since.
Strap hinges continued to dominate in the marketplace for hanging shutters. Drive pintles started to be replaced by similar pintles cut off and mounted on a piece of thin plate material and again fastened with the new screws. This is the precursor of the "plate pintle".
Changes in construction have been noted in the same period. Structures were built with openings into which pre-fabricated windows were installed. The earliest examples date from around 1810 and used a variation on the strap hinge. Instead of mounting the pintle to the surface of the structure, a new form was designed. This pintle was a flat plate of about two inches high and notched to one half of its height and formed to a female barrel. Holes were punched in the side of the pintle, and it was screwed directly to the side of the window before the window was installed on the structure. The strap hinges were modified to match the new pintles and the hinge was of the same width as the pintle and notched to one half of its height. A pin to mate with the female pintle was welded in the hinge. Examples of this type proved to be very durable and were in regular and widespread use through the 1870s.
Often when the shutters were removed – usually in the 20th century – cast type pintles were hit with a hammer and broken off flush with the edge of the window. The shutters often found their way into the basements of the home to provide coal bins for newly installed central heat or were nailed up in the barn to partition off pig sties or calf pens.
Cast iron tie-backs became much more popular during the Federal period – usually mounted on arms extending from the window sills. The "Federal Shell" was the dominant pattern in this period. | 1 | Applied and Interdisciplinary Chemistry |
Electrohydrogenesis or biocatalyzed electrolysis is the name given to a process for generating hydrogen gas from organic matter being decomposed by bacteria. This process uses a modified fuel cell to contain the organic matter and water. A small amount, 0.2–0.8 V of electricity is used, the original article reports an overall energy efficiency of 288% can be achieved (this is computed relative to the amount of electricity used, waste heat lowers the overall efficiency). This work was reported by Cheng and Logan. | 1 | Applied and Interdisciplinary Chemistry |
In host–guest chemistry, a carceplex is a class of chemical structures in the carcerand family that are hinged, and can be closed using reagents that react with the carceplex and trap precursors of reactive intermediates, and are unreactive with the trapped precursor or reactive intermediate. This is useful for determining the spectroscopic and crystallographic properties of reactive intermediates in relative isolation, particularly compounds prone to dimerization like cyclobutadiene. | 0 | Theoretical and Fundamental Chemistry |
V. G. Khlopin developed a method of mechanical enrichment to improve the quality of raw barium-radium sulfates rich in silica (together with engineer S. P. Alexandrov). Later, the scientist transformed the Curie-Debierne method of conversion of sulfates into carbonates under the condition of saturation of sulfates with silica - through the combination of soda with caustic soda (together with P. A. Volkov).
On the basis of theoretical assumptions, V. G. Khlopin proposed several methods of fractional crystallization of barium-radium salts, excluding evaporation of solutions - by increasing the concentration of the same ion in the cold: fractional precipitation of chlorides with hydrochloric acid (1921), fractional precipitation of bromides (together with M. A. Pasvik, 1923), fractional precipitation of nitrates (with P. I. Tolmachev, with A. P. Ratner, 1924-1930). A. Pasvik, 1923), fractional precipitation of nitrates (with P. I. Tolmachev, with A. P. Ratner, 1924-1930), fractional precipitation of chromates (M. S. Merkulova), fractional precipitation of chlorides with zinc chloride (I. Y. Bashilov and Y. S. Vilnyansky, 1926).
In 1924, V. G. Khlopin created a general theory of the fractional crystallization process, which greatly facilitated the calculation of the technological process in general and the development of the required apparatus for its implementation in particular. A number of versions of the conventional crystallization scheme were hereby based on calculations used in plant practice. Later this theory was applied and developed in the All-Russian Research Institute of Chemical Reagents and Particularly Pure Chemicals for obtaining chemically pure substances by recrystallization. | 0 | Theoretical and Fundamental Chemistry |
Supercritical carbon dioxide is used to enhance oil recovery in mature oil fields. At the same time, there is the possibility of using "clean coal technology" to combine enhanced recovery methods with carbon sequestration. The CO is separated from other flue gases, compressed to the supercritical state, and injected into geological storage, possibly into existing oil fields to improve yields.
At present, only schemes isolating fossil CO from natural gas actually use carbon storage, (e.g., Sleipner gas field), but there are many plans for future CCS schemes involving pre- or post- combustion CO. There is also the possibility to reduce the amount of CO in the atmosphere by using biomass to generate power and sequestering the CO produced. | 0 | Theoretical and Fundamental Chemistry |
Bases: adenine (A), cytosine (C), guanine (G) and thymine (T) or uracil (U).
Amino acids: Alanine (Ala, A), Arginine (Arg, R), Asparagine (Asn, N), Aspartic acid (Asp, D), Cysteine (Cys, C), Glutamic acid (Glu, E), Glutamine (Gln, Q), Glycine (Gly, G), Histidine (His, H), Isoleucine (Ile, I), Leucine (Leu, L), Lysine (Lys, K), Methionine (Met, M), Phenylalanine (Phe, F), Proline (Pro, P), Serine (Ser, S), Threonine (Thr, T), Tryptophan (Trp, W), Tyrosine (Tyr, Y), Valine (Val, V) | 1 | Applied and Interdisciplinary Chemistry |
The yeast interactome, i.e. all protein–protein interactions among proteins of Saccharomyces cerevisiae, has been estimated to contain between 10,000 and 30,000 interactions. A reasonable estimate may be on the order of 20,000 interactions. Larger estimates often include indirect or predicted interactions, often from affinity purification/mass spectrometry (AP/MS) studies. | 1 | Applied and Interdisciplinary Chemistry |
Organic photosensitizers are carbon-based molecules which are capable of photosensitizing. The earliest studied photosensitizers were aromatic hydrocarbons which absorbed light in the presence of oxygen to produce reactive oxygen species. These organic photosensitizers are made up of highly conjugated systems which promote electron delocalization. Due to their high conjugation, these systems have a smaller gap between the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) as well as a continuum of orbitals within the HOMO and LUMO. The smaller band gap and the continuum of orbitals in both the conduction band and the valence band allow for these materials to enter their triplet state more efficiently, making them better photosensitizers. Some notable organic photosensitizers which have been studied extensively include benzophenones, methylene blue, and rose Bengal. | 0 | Theoretical and Fundamental Chemistry |
In general, a geometric lattice is an infinite, regular array of vertices (points) in space, which can be modelled vectorially as a Bravais lattice. Some lattices may be skew, which means that their primary lines may not necessarily be at right angles. In reciprocal space, a reciprocal lattice is defined as the set of wavevectors of plane waves in the Fourier series of any function whose periodicity is compatible with that of an initial direct lattice in real space. Equivalently, a wavevector is a vertex of the reciprocal lattice if it corresponds to a plane wave in real space whose phase at any given time is the same (actually differs by with an integer ) at every direct lattice vertex.
One heuristic approach to constructing the reciprocal lattice in three dimensions is to write the position vector of a vertex of the direct lattice as , where the are integers defining the vertex and the are linearly independent primitive translation vectors (or shortly called primitive vectors) that are characteristic of the lattice. There is then a unique plane wave (up to a factor of negative one), whose wavefront through the origin contains the direct lattice points at and , and with its adjacent wavefront (whose phase differs by or from the former wavefront passing the origin) passing through . Its angular wavevector takes the form , where is the unit vector perpendicular to these two adjacent wavefronts and the wavelength must satisfy , means that is equal to the distance between the two wavefronts. Hence by construction and .
Cycling through the indices in turn, the same method yields three wavevectors with , where the Kronecker delta equals one when and is zero otherwise. The comprise a set of three primitive wavevectors or three primitive translation vectors for the reciprocal lattice, each of whose vertices takes the form , where the are integers. The reciprocal lattice is also a Bravais lattice as it is formed by integer combinations of the primitive vectors, that are , , and in this case. Simple algebra then shows that, for any plane wave with a wavevector on the reciprocal lattice, the total phase shift between the origin and any point on the direct lattice is a multiple of (that can be possibly zero if the multiplier is zero), so the phase of the plane wave with will essentially be equal for every direct lattice vertex, in conformity with the reciprocal lattice definition above. (Although any wavevector on the reciprocal lattice does always take this form, this derivation is motivational, rather than rigorous, because it has omitted the proof that no other possibilities exist.)
The Brillouin zone is a primitive cell (more specifically a Wigner–Seitz cell) of the reciprocal lattice, which plays an important role in solid state physics due to Bloch's theorem. In pure mathematics, the dual space of linear forms and the dual lattice provide more abstract generalizations of reciprocal space and the reciprocal lattice. | 0 | Theoretical and Fundamental Chemistry |
Spin exchange optical pumping can continue indefinitely with continuous illumination, but there are several factors that cause relaxation of polarization and thus a return to the thermal equilibrium populations when illumination is stopped. In order to use hyperpolarized noble gases in applications such as lung imaging, the gas must be transferred from the experimental setup to a patient. As soon as the gas is no longer actively being optically pumped, the degree of hyperpolarization begins to decrease until thermal equilibrium is reached. However, the hyperpolarization must last long enough to transfer the gas to the patient and obtain an image. The longitudinal spin relaxation time, denoted as T, can be measured easily by collecting NMR spectra as the polarization decreases over time once illumination is stopped. This relaxation rate is governed by several depolarization mechanisms and is written as:
Where the three contributing terms are for collisional relaxation (CR), magnetic field inhomogeneity (MFI) relaxation, and relaxation caused by the presence of paramagnetic oxygen (O2). The T duration could be anywhere from minutes to several hours, depending on how much care is put into lessening the effects of CR, MFI, and O. The last term has been quantified to be 0.360 s amagat, but the first and second terms are hard to quantify since the degree of their contribution to the overall T is dependent on how well the experimental setup and cell are optimized and prepared. | 0 | Theoretical and Fundamental Chemistry |
* Fellow of the Royal Society of Chemistry (1970)
* Fellow of the Royal Society (1976), Vice-President 1987-1988
* Chugaev Medal of the Kurnakov Institute (Russian Academy of Sciences) (1978)
* Royal Society of Chemistry’s Ludwig Mond Award (1983)
* American Chemical Society’s award in Inorganic Chemistry (1985)
* Royal Society of Chemistry’s Sir Edward Frankland Prize Lectureship (1988)
* Royal Society's Davy Medal (1989)
* Royal Society of Chemistry’s Longstaff Prize (1990)
* Commander of the Order of the British Empire (1990) | 0 | Theoretical and Fundamental Chemistry |
Paytan was born and raised in Israel. As an undergraduate, Paytan encountered geochemistry which she likens to a big complex puzzle. Paytan obtained undergraduate degrees in geology and biology (1985) and an M.S. in Earth Sciences Oceanography (1989) from Hebrew University of Jerusalem. Paytan's Ph.D. is from Scripps Institution of Oceanography (1996) where she worked with Miriam Kastner on using barite as a recorder of ocean chemistry. After postdoctoral work at University of California, San Diego she moved to the Department of Geological and Environmental Sciences at Stanford, and then onto a position at University of California, Santa Cruz. | 0 | Theoretical and Fundamental Chemistry |
The unlinked galR gene encodes the repressor for this system. A tetrameric GalR repressor binds to 2 operators, one located at +55 and one located at -60 relative to the PG1 start site. Looping of the DNA blocks the access of RNA polymerase to promoters and/or inhibits formation of the open complex. This looping requires the presence of the histone-like protein, HU to facilitate the formation of the structure and allow for proper repression. When GalR binds as a dimer to the -60 site only, the promoter PG2 is activated, not repressed, allowing basal levels of GalE to be produced. In this state, the PG1 promoter is inactivated through interactions with the alpha subunit of RNA polymerase. Activity of this repressor protein is controlled based on the levels of D-galactose in the cell. Increased levels of this sugar inhibit the activity of the repressor by binding allosterically, resulting in a conformational change of the protein, which suppresses its interactions with RNA polymerase and DNA. This induces the activity of the operon, which will increase the rate of galactose metabolism.
The gal operon is also controlled by CRP-cAMP, similarly to the lac operon. CRP-cAMP binds to the -35 region, promoting transcription from PG1 but inhibiting transcription from PG2. This is accomplished due to the location of the activation sequence. When CRP-cAMP binds the activating sequence, it blocks RNA polymerase from establishing an open complex with PG2, but enhances a closed complex with RNA polymerase at PG1. This represses the activity of the PG2 promoter, and increases the activity of the PG1 promoter. When cells are grown in glucose, basal level transcription occurs from PG2. | 1 | Applied and Interdisciplinary Chemistry |
Using the appropriate reagent and conditions, alkyl, alkenyl, allylic, and α-keto sulfones may be reduced in good yield and high stereoselectivity (where applicable). Appropriate conditions for the reduction of these classes of sulfones are discussed below.
Alkyl sulfones may be reduced with sodium or lithium in liquid ammonia; however, the strongly basic conditions of these dissolving metal reductions represent a significant disadvantage. In alcoholic solvents, magnesium metal and a catalytic amount of mercury(II) chloride may be used. A wide variety of functional groups are unaffected by these conditions, including many that are transformed by dissolving metal reductions. Reductive desulfonylation with these reagents does not occur in reactions of β-hydroxy sulfones, due to the poor leaving group ability of the hydroxyl group.
A significant issue associated with the reduction of allylic sulfones is transposition of the allylic double bond, which occurs in varying amounts during reductions by metal amalgams. and tin hydrides Palladium-catalyzed reductive desulfonylations of allylic sulfones do not have this issue, and afford allylic sulfones with high site and stereoselectivity.
Aluminum amalgam (Al/Hg) may be used for the chemoselective reduction of α-sulfonylated carbonyl groups. Carboxylic acid derivatives, acetals, thioacetals, amines, alcohols, and isolated double bonds are all inert to Al/Hg. Selective desulfonylation may be carried out on β-hydroxy sulfones without reductive elimination.
Transition metal catalysis is also useful for the stereospecific reduction of alkenyl sulfones. In the presence of an excess of a Grignard reagent, a palladium(II) or nickel(II) catalyst, and a phosphorus or nitrogen ligand, alkenyl sulfones are converted to the corresponding alkenes stereospecifically in good yield. On the other hand, dissolving metal and metal amalgam reductions are not stereoselective in general. Palladium catalysis is generally superior to nickel catalysis, giving higher yields and stereoselectivities.
Alkyl and alkenyl sulfones with good leaving groups in the β position undergo elimination under reductive conditions to afford alkenes or alkynes. The Julia olefination exploits this process for the synthesis of alkenes from alkyl sulfones and carbonyl compounds. Addition of an α-sulfonyl anion to a carbonyl compound, followed by quenching with an acyl or sulfonyl chloride, leads to a β-acyloxy or -sulfonyloxy sulfone, which undergoes elimination under reductive conditions. Sodium amalgam may be used to accomplish the elimination step; however, the combination of samarium(II) iodide and HMPA is milder than strongly basic sodium amalgam and leads to higher yields in reductive elimination processes. | 0 | Theoretical and Fundamental Chemistry |
Wnt signaling and β-catenin dependent gene expression plays a critical role during the formation of different body regions in the early embryo. Experimentally modified embryos that do not express this protein will fail to develop mesoderm and initiate gastrulation.
Early embryos endomesoderm specification also involves the activation of the β-catenin dependent transcripional activity by the first morphogenetic movements of embryogenesis, though mechanotransduction processes. This feature being shared by vertebrate and arthropod bilateria, and by cnidaria, it was proposed to have been evolutionary inherited from its possible involvement in the endomesoderm specification of first metazoa.
During the blastula and gastrula stages, Wnt as well as BMP and FGF pathways will induce the antero-posterior axis formation, regulate the precise placement of the primitive streak (gastrulation and mesoderm formation) as well as the process of neurulation (central nervous system development).
In Xenopus oocytes, β-catenin is initially equally localized to all regions of the egg, but it is targeted for ubiquitination and degradation by the β-catenin destruction complex. Fertilization of the egg causes a rotation of the outer cortical layers, moving clusters of the Frizzled and Dsh proteins closer to the equatorial region. β-catenin will be enriched locally under the influence of Wnt signaling pathway in the cells that inherit this portion of the cytoplasm. It will eventually translocate to the nucleus to bind TCF3 in order to activate several genes that induce dorsal cell characteristics. This signaling results in a region of cells known as the grey crescent, which is a classical organizer of embryonic development. If this region is surgically removed from the embryo, gastrulation does not occur at all. β-Catenin also plays a crucial role in the induction of the blastopore lip, which in turn initiates gastrulation. Inhibition of GSK-3 translation by injection of antisense mRNA may cause a second blastopore and a superfluous body axis to form. A similar effect can result from the overexpression of β-catenin. | 1 | Applied and Interdisciplinary Chemistry |
Proton precession magnetometers, also known as proton magnetometers, PPMs or simply mags, measure the resonance frequency of protons (hydrogen nuclei) in the magnetic field to be measured, due to nuclear magnetic resonance (NMR). Because the precession frequency depends only on atomic constants and the strength of the ambient magnetic field, the accuracy of this type of magnetometer can reach 1 ppm.
A direct current flowing in a solenoid creates a strong magnetic field around a hydrogen-rich fluid (kerosene and decane are popular, and even water can be used), causing some of the protons to align themselves with that field. The current is then interrupted, and as protons realign themselves with the ambient magnetic field, they precess at a frequency that is directly proportional to the magnetic field. This produces a weak rotating magnetic field that is picked up by a (sometimes separate) inductor, amplified electronically, and fed to a digital frequency counter whose output is typically scaled and displayed directly as field strength or output as digital data.
For hand/backpack carried units, PPM sample rates are typically limited to less than one sample per second. Measurements are typically taken with the sensor held at fixed locations at approximately 10 metre increments.
Portable instruments are also limited by sensor volume (weight) and power consumption. PPMs work in field gradients up to 3,000 nT/m, which is adequate for most mineral exploration work. For higher gradient tolerance, such as mapping banded iron formations and detecting large ferrous objects, Overhauser magnetometers can handle 10,000 nT/m, and caesium magnetometers can handle 30,000 nT/m.
They are relatively inexpensive (< US$8,000) and were once widely used in mineral exploration. Three manufacturers dominate the market: GEM Systems, Geometrics and Scintrex. Popular models include G-856/857, Smartmag, GSM-18, and GSM-19T.
For mineral exploration, they have been superseded by Overhauser, caesium, and potassium instruments, all of which are fast-cycling, and do not require the operator to pause between readings. | 0 | Theoretical and Fundamental Chemistry |
Diffusiophoresis is the spontaneous motion of colloidal particles or molecules in a fluid, induced by a concentration gradient of a different substance. In other words, it is motion of one species, A, in response to a concentration gradient in another species, B. Typically, A is colloidal particles which are in aqueous solution in which B is a dissolved salt such as sodium chloride, and so the particles of A are much larger than the ions of B. But both A and B could be polymer molecules, and B could be a small molecule. For example, concentration gradients in ethanol solutions in water move 1 μm diameter colloidal particles with diffusiophoretic velocities of order 0.1 to 1 μm/s, the movement is towards regions of the solution with lower ethanol concentration (and so higher water concentration). Both species A and B will typically be diffusing but diffusiophoresis is distinct from simple diffusion: in simple diffusion a species A moves down a gradient in its own concentration.
Diffusioosmosis, also referred to as capillary osmosis, is flow of a solution relative to a fixed wall or pore surface, where the flow is driven by a concentration gradient in the solution. This is distinct from flow relative to a surface driven by a gradient in the hydrostatic pressure in the fluid. In diffusioosmosis the hydrostatic pressure is uniform and the flow is due to a concentration gradient.
Diffusioosmosis and diffusiophoresis are essentially the same phenomenon. They are both relative motion of a surface and a solution, driven by a concentration gradient in the solution. This motion is called diffusiophoresis when the solution is considered static with particles moving in it due to relative motion of the fluid at the surface of these particles. The term diffusioosmosis is used when the surface is viewed as static, and the solution flows.
A well studied example of diffusiophoresis is the motion of colloidal particles in an aqueous solution of an electrolyte solution, where a gradient in the concentration of the electrolyte causes motion of the colloidal particles. Colloidal particles may be hundred of nanometres or larger in diameter, while the interfacial double layer region at the surface of the colloidal particle will be of order the Debye length wide, and this is typically only nanometres. So here, the interfacial width is much smaller than the size of the particle, and then the gradient in the smaller species drives diffusiophoretic motion of the colloidal particles largely through motion in the interfacial double layer.
Diffusiophoresis was first studied by Derjaguin and coworkers in 1947. | 0 | Theoretical and Fundamental Chemistry |
The basic principles of physics and the Coriolis effect define an approximate geostrophic wind or gradient wind, balanced flows that are parallel to the isobars. Measurements of wind speed and direction at heights well above ground level confirm that wind matches these approximations quite well. However, nearer the Earths surface, the wind speed is less than predicted by the barometric pressure gradient, and the wind direction is partly across the isobars rather than parallel to them. This flow of air across the isobars is a secondary flow'., a difference from the primary flow which is parallel to the isobars. Interference by surface roughness elements such as terrain, waves, trees and buildings cause drag on the wind and prevent the air from accelerating to the speed necessary to achieve balanced flow. As a result, the wind direction near ground level is partly parallel to the isobars in the region, and partly across the isobars in the direction from higher pressure to lower pressure.
As a result of the slower wind speed at the earths surface, in a region of low pressure the barometric pressure is usually significantly higher at the surface than would be expected, given the barometric pressure at mid altitudes, due to Bernoullis principle. Hence, the secondary flow toward the center of a region of low pressure is also drawn upward by the significantly lower pressure at mid altitudes. This slow, widespread ascent of the air in a region of low pressure can cause widespread cloud and rain if the air is of sufficiently high relative humidity.
In a region of high pressure (an anticyclone) the secondary flow includes a slow, widespread descent of air from mid altitudes toward ground level, and then outward across the isobars. This descent causes a reduction in relative humidity and explains why regions of high pressure usually experience cloud-free skies for many days. | 1 | Applied and Interdisciplinary Chemistry |
In fluid mechanics, apparent viscosity (sometimes denoted ) is the shear stress applied to a fluid divided by the shear rate:
For a Newtonian fluid, the apparent viscosity is constant, and equal to the Newtonian viscosity of the fluid, but for non-Newtonian fluids, the apparent viscosity depends on the shear rate. Apparent viscosity has the SI derived unit Pa·s (Pascal-second), but the centipoise is frequently used in practice: (1 mPa·s = 1 cP). | 1 | Applied and Interdisciplinary Chemistry |
CKIα or CKIδ is essential in modulating the nuclear export of eukaryotic translation initiation factor 6 (eIF6), a protein with essential nuclear and cytoplasmic roles in biogenesis of the 60S subunit of the eukaryotic ribosome. Phosphorylation of Ser-174 and Ser-175 by CKI promotes nuclear export of eIF6 while dephosphorylation by calcineurin promotes nuclear accumulation of eIF6. It is unclear whether the same mechanism is responsible for eIF6 cycling in yeast and if other kinases also play roles in these processes.
CKI homologs are also implicated in cytoplasmic shuttling of nuclear factor of activated T-cells (NFAT) through observation that the transcription factor Crz1p is phosphorylated by a CKI homolog in yeast. | 1 | Applied and Interdisciplinary Chemistry |
Nuclear Medicine and Biology is a peer-reviewed medical journal published by Elsevier that covers research on all aspects of nuclear medicine, including radiopharmacology, radiopharmacy and clinical studies of targeted radiotracers. It is the official journal of the Society of Radiopharmaceutical Sciences. According to the Journal Citation Reports, the journal has a 2011 impact factor of 3.023. | 0 | Theoretical and Fundamental Chemistry |
False brinelling was first mentioned by Almen in 1937. Almen found that wheel bearings were damaged before they were used by customers. Furthermore, he found that the bearings were more damaged for long-distance shipping of the cars and that the season of shipping also had an influence. The reason for the damaged bearings were micro-oscillations which occurred due to the shipping. The small oscillations result in fatigue cracking, followed by release of particles that subsequently start to abrasively damage the contact area between a ball and the bearing race, resulting in a typical wear damage. Because the damage has a similar look to brinelling, it was called false brinelling.
Although the car-delivery problem has been solved, there are many modern examples. A major maintenance problem are the pitch bearings in wind turbines, for which specialty greases had to be developed that result in almost no false brinelling damage. Similar damage may also occur in electric and electronic contacts that are subjected to vibrations during use, think of aerospace and automotive connectors and even remote control battery compartments. Although the damage in these areas may not be as severe as the false brinelling in bearings, the damage mechanisms are similar and result in the creation of particles in the contact that can severely influence the electrical connection.
Also, generators or pumps may fail or need service because of this damage, so it is common to have a nearby spare unit which is left off most of the time but brought into service when needed. Surprisingly, however, vibration from the operating unit can cause bearing failure in the unit which is switched off. When that unit is turned on, the bearings may be noisy due to damage, and may fail completely within a few days or weeks even though the unit and its bearings are otherwise new. Common solutions include: keeping the spare unit at a distance from the one which is on and vibrating; manually rotating shafts of the spare units on a regular (for example, weekly) basis; or regularly switching between the units so that both are in regular (for example, weekly) operation.
Until recently, bicycle headsets tended to suffer from false brinelling in the "straight ahead" steering position, due to small movements caused by flexing of the fork. Good modern headsets incorporate a plain bearing to accommodate this flexing, leaving the ball race to provide pure rotational movement.
Bearings of modern wind turbines are often affected by false brinelling. Especially the pitch bearing, which is used under oscillation, shows often false brinelling damages. | 1 | Applied and Interdisciplinary Chemistry |
An example of a repressor protein is the methionine repressor MetJ. MetJ interacts with DNA bases via a ribbon-helix-helix (RHH) motif. MetJ is a homodimer consisting of two monomers, which each provides a beta ribbon and an alpha helix. Together, the beta ribbons of each monomer come together to form an antiparallel beta-sheet which binds to the DNA operator ("Met box") in its major groove. Once bound, the MetJ dimer interacts with another MetJ dimer bound to the complementary strand of the operator via its alpha helices. AdoMet binds to a pocket in MetJ that does not overlap the site of DNA binding.
The Met box has the DNA sequence AGACGTCT, a palindrome (it shows dyad symmetry) allowing the same sequence to be recognized on either strand of the DNA. The junction between C and G in the middle of the Met box contains a pyrimidine-purine step that becomes positively supercoiled forming a kink in the phosphodiester backbone. This is how the protein checks for the recognition site as it allows the DNA duplex to follow the shape of the protein. In other words, recognition happens through indirect readout of the structural parameters of the DNA, rather than via specific base sequence recognition.
Each MetJ dimer contains two binding sites for the cofactor S-Adenosyl methionine (SAM) which is a product in the biosynthesis of methionine. When SAM is present, it binds to the MetJ protein, increasing its affinity for its cognate operator site, which halts transcription of genes involved in methionine synthesis. When SAM concentration becomes low, the repressor dissociates from the operator site, allowing more methionine to be produced. | 1 | Applied and Interdisciplinary Chemistry |
More detailed computation simulations can be carried out accounting for not cellular models, but taking into consideration the functional syncytium and enabling the cells to mutually interact, the so-called electrotonic coupling.
In case of tissue simulation or in wider cases, such as in whole organ simulations, all the cellular models are note applicable anymore, and several corrections have to be made. Firstly, the governing equations can not be just ordinary differential equations, but a system of partial differential equations has to be accounted for. A suitable choice may be the monodomain model:
<math>\triangledown \cdot(D\nabla V)=(C_m\frac{\partial V}{\partial t} + I_{ion}(V,u))
where is the effective conductivity tensor, is the capacitance of the cellular membrane, the transmembrane ionic current, and are the domain of interest and its boundary, respectively, with the outward boundary of . | 1 | Applied and Interdisciplinary Chemistry |
Suitable tripodal compounds, such as trimesic acid and nitrilotriacetic acid, can be converted directly to trisoxazolines. The simplicity of this approach is beneficial, however it only allows a limited variety of structures to be produced, due to the limited range of available starting materials. | 0 | Theoretical and Fundamental Chemistry |
Pyroelectric charge in minerals develops on the opposite faces of asymmetric crystals. The direction in which the propagation of the charge tends is usually constant throughout a pyroelectric material, but, in some materials, this direction can be changed by a nearby electric field. These materials are said to exhibit ferroelectricity.
All known pyroelectric materials are also piezoelectric. Despite being pyroelectric, novel materials such as boron aluminum nitride (BAlN) and boron gallium nitride (BGaN) have zero piezoelectric response for strain along the c-axis at certain compositions, the two properties being closely related. However, note that some piezoelectric materials have a crystal symmetry that does not allow pyroelectricity.
Pyroelectric materials are mostly hard and crystals; however, soft pyroelectricity can be achieved by using electrets.
Pyroelectricity is measured as the change in net polarization (a vector) proportional to a change in temperature. The total pyroelectric coefficient measured at constant stress is the sum of the pyroelectric coefficients at constant strain (primary pyroelectric effect) and the piezoelectric contribution from thermal expansion (secondary pyroelectric effect). Under normal circumstances, even polar materials do not display a net dipole moment. As a consequence, there are no electric dipole equivalents of bar magnets because the intrinsic dipole moment is neutralized by "free" electric charge that builds up on the surface by internal conduction or from the ambient atmosphere. Polar crystals only reveal their nature when perturbed in some fashion that momentarily upsets the balance with the compensating surface charge.
Spontaneous polarization is temperature dependent, so a good perturbation probe is a change in temperature which induces a flow of charge to and from the surfaces. This is the pyroelectric effect. All polar crystals are pyroelectric, so the 10 polar crystal classes are sometimes referred to as the pyroelectric classes. Pyroelectric materials can be used as infrared and millimeter wavelength radiation detectors.
An electret is the electrical equivalent of a permanent magnet. | 0 | Theoretical and Fundamental Chemistry |
Another area of active research is using TPV as the basis of a thermal storage system. In this concept, electricity being generated in off-peak times is used to heat a large block of material, typically carbon or a phase-change material. The material is surrounded by TPV cells which are in turn backed by a reflector and insulation. During storage, the TPV cells are turned off and the photons pass through them and reflect back into the high-temperature source. When power is needed, the TPV is connected to a load. | 0 | Theoretical and Fundamental Chemistry |
Sarcalumenin is a protein that in humans is encoded by the SRL gene.
Sarcalumenin is a calcium-binding protein that can be found in the sarcoplasmic reticulum of striated muscle. Sarcalumenin is partially responsible for calcium buffering in the lumen of the sarcoplasmic reticulum and helps out calcium pump proteins. Additionally, sarcalumenin is necessary for keeping a normal sinus rhythm during both aerobic and anaerobic exercise activity. Sarcalumenin is a calcium-binding glycoprotein composed of 473 acidic amino acids with a molecular weight of 160 KDa. Together along with other luminal calcium buffer proteins, sarcalumenin plays an important role in regulation of calcium uptake and release during excitation-contraction coupling (ECC) in muscle fibers. | 1 | Applied and Interdisciplinary Chemistry |
In view of its performance, the process seemed a suitable basis for the development of more efficient variants. Around 1940, the Japanese built several small reduction furnaces operating at lower temperatures: one at Tsukiji (1.8 m × 60 m), two at Hachinohe (2 furnaces of 2.8 m × 50 m), and three at Takasago (2 furnaces of 1.83 m × 27 m and 1 furnace of 1.25 m × 17 m). However, since they do not produce Luppen, they cannot be equated with the Krupp-Renn process.
Although direct reduction in a rotary furnace has been the subject of numerous developments, the logical descendant of the Krupp-Renn process is the "Krupp-CODIR process". Developed in the 1970s, it is based on the general principles of the Krupp-Renn process with a lower temperature reduction, typically between 950 and 1,050 °C, which saves fuel but is insufficient to achieve partial melting of the charge. The addition of basic corrective additives (generally limestone or dolomite) mixed with the ore allows the removal of sulfur from the coal, although the thermolysis of these additives is highly endothermic. This process has been adopted by three plants: Dunswart Iron & Steel Works in South Africa in 1973, Sunflag Iron and Steel in 1989, and Goldstar Steel & Alloy in India in 1993. Although the industrial application is now well established, the process has not had the impact of its predecessor.
Finally, there are many post-Krupp-Renn direct reduction processes based on a tubular rotary furnace. At the beginning of the 21st century, their combined output represented between 1% and 2% of world steel production. In 1935 and 1960, the output of the Krupp-Renn process (1 and 2 million tons respectively) represented just under 1% of world steel production. | 1 | Applied and Interdisciplinary Chemistry |
Experiments have shown that siphons can operate in a vacuum, via cohesion and tensile strength between molecules, provided that the liquids are pure and degassed and surfaces are very clean. | 1 | Applied and Interdisciplinary Chemistry |
Bacteria containing the plasmid of interest are first cultured, then a sample is centrifuged in order to concentrate cellular material (including DNA) into a pellet at the bottom of the containing vessel. The supernatant is discarded, and the pellet is then re-suspended in an EDTA-containing physiological buffer. The purpose of the EDTA is to chelate divalent metal cations such as Mg and Ca, which are required for the function of DNA degrading enzymes (DNAses) and also serve to de-stabilise the DNA phosphate backbone and cell wall. Glucose in the buffer will maintain the osmotic pressure of the cell in order to prevent the cell from bursting. Tris in the buffer will retain the pH of the cell with 8.0 and RNase will remove the RNA which will disrupt the experiment.
Separately, a strong alkaline solution consisting of the detergent sodium dodecyl sulfate (SDS) and a strong base such as sodium hydroxide (NaOH) is prepared and then added. The resulting mixture is incubated for a few minutes. During this time, the detergent disrupts cell membranes and allows the alkali to contact and denature both chromosomal and plasmid DNA.
After tearing apart the cell membrane by SDS, the cell content will neutralize the NaOH; this is why the pH of the lysis goes down from 12.8 to 12.3. So if there are not enough bacterial cells, the extra NaOH will function to generate small DNA fragments. But 0.5 M L-arginine, which can supply a stable pH, can be used to replace 0.1 M sodium hydroxide.
Finally, potassium acetate is added. This acidifies the solution and allows the renaturing of plasmid DNA, but not chromosomal DNA, which is precipitated out of solution. Another function of the potassium is to cause the precipitation of sodium dodecyl sulfate and thus removal of the detergent. A final centrifugation is carried out, and this time the pellet contains only debris and can be discarded. The plasmid-containing supernatant is carefully removed and can be further purified or used for analysis, such as gel electrophoresis. | 1 | Applied and Interdisciplinary Chemistry |
Vanillin has been used as a chemical intermediate in the production of pharmaceuticals, cosmetics, and other fine chemicals. In 1970, more than half the world's vanillin production was used in the synthesis of other chemicals. As of 2016, vanillin uses have expanded to include perfumes, flavoring and aromatic masking in medicines, various consumer and cleaning products, and livestock foods. | 0 | Theoretical and Fundamental Chemistry |
The Pattinson process was patented by its inventor, Hugh Lee Pattinson, in 1833 who described it as "An improved method for separating silver from lead". It exploited the fact that in molten lead containing traces of silver the first metal to solidify out of the melt is lead, leaving the remaining liquid richer in silver. Pattinson's equipment consisted basically of nothing more complex than a row of up to 13 iron pots, which were heated from below. Some lead, naturally containing a small percentage of silver, was loaded into the central pot and melted. This was then allowed to cool. As the lead solidified it is removed using large perforated iron ladles and moved to the next pot in one direction, and the remaining metal which was now richer in silver was then transferred to the next pot in the opposite direction. The process was repeated from one pot to the next, the lead accumulating in the pot at one end and metal enriched in silver in the pot at the other. The level of enrichment possible is limited by the lead-silver eutectic and typically the process stopped around 600 to 700 ounces per ton (approx 2%), so further separation is carried out by cupellation.
The process was economic for lead containing at least 250 grams of silver per ton. | 1 | Applied and Interdisciplinary Chemistry |
Corrosion inhibitors, such as gas-phase or volatile inhibitors, can be used to prevent corrosion inside sealed systems. They are not effective when air circulation disperses them, and brings in fresh oxygen and moisture. | 1 | Applied and Interdisciplinary Chemistry |
The ash content of a sample is a measure of the amount of inorganic noncombustible material it contains. The residues after a sample is completely burnt - in contrast to the ash remaining after incomplete combustion - typically consist of oxides of the inorganic elements present in the original sample. Ash is one of the components in the proximate analysis of biological materials, consisting mainly of salty, inorganic constituents. It includes metal salts which are important for processes requiring ions such as Na (sodium), K (potassium), and Ca (calcium). It also includes trace minerals which are required for unique molecules, such as chlorophyll and hemoglobin.
Procedures for ash content determination are similar to procedures for loss on ignition. Typically, the term ash is used for primarily organic material such as fuels and foodstuffs, while the term loss on ignition is used for primarily inorganic material such as rocks and combusted ash.
A crucible can be used to determine the percentage of ash contained in a sample of material such as coal, wood, oil, rubber, plastics, foodstuffs, or any burnable material. The appropriate method for ash determination varies depending upon the type of sample analyzed. Each method may vary in parameters such as furnace temperature, residence time in the furnace, number of heating steps, and sample preparation procedures.
The ISO mandates ash content determination for most foodstuffs. Examples include
* ISO 2171: Cereals, pulses and by-products — Determination of ash yield by incineration;
* ISO 3593: Starch — Determination of ash;
* ISO 928: Spices and condiments - Determination of total ash; and
* ISO 936: Meat and meat products - Determination of total ash.
Examples of ash content methods for the determination of ash in other solids include
* ASTM D482: Standard Test Method for Ash from Petroleum Products;
* ISO 6245: Petroleum products — Determination of ash;
* ASTM D874: Standard Test Method for Sulfated Ash from Lubricating Oils and Additives;
* ASTM D3174: Standard Test Method for Ash in the Analysis Sample of Coal and Coke from Coal;
* ISO 1171: Solid mineral fuels — Determination of ash;
* ISO 18122: Solid biofuels — Determination of ash content;
* ASTM D1102: Standard Test Method for Ash in Wood;
* ASTM D2974: Standard Test Methods for Determining the Water (Moisture) Content, Ash Content, and Organic Material of Peat and Other Organic Soils;
* ASTM D2866: Standard Test Method for Total Ash Content of Activated Carbon;
* ISO 3451: Plastics — Determination of ash — Part 1: General methods;
* ASTM D2584: Standard Test Method for Ignition Loss of Cured Reinforced Resins; and
* ASTM D5630: Standard Test Method for Ash Content in Plastics. | 0 | Theoretical and Fundamental Chemistry |
In the 1990s, Place turned his attention as an illustrator to the creation of tarot decks and began his career as an author. Place is best known as the creator of The Alchemical Tarot, his first deck and book combination, which is illustrated in the style of 17th century alchemical engravings and which presents a parallel between the “great work” of alchemy, which leads to the creation of the philosopher’s stone and the allegory in the tarot’s trumps.
In his other decks, The Angels Tarot, The Tarot of the Saints, and The Buddha Tarot, Place has explored the connection between religion, mysticism, and the tarot’s symbolism.
In his fifth book, The Tarot: History, Symbolism, and Divination, his first book published not in connection with a tarot deck, Place contributed to the field of tarot history by discussing the images in the tarot in relation to the iconography of the 15th century Italian Renaissance, the era when the tarot was created. Place relates each image in the tarot to similar images created at that time and presents a theory of interpretation that is rooted in the art and philosophy of the time. The book also discusses contrasting occult theories and champions Pamela Colman Smith as the primary designer of the Waite–Smith tarot.
The Tarotpedia has said that The Tarot: History, Symbolism, and Divination “is bound to find a place amongst the most important works published this decade.”
"Booklist", the publication of the American Library Association, has said that The Tarot: History, Symbolism, and Divination “may be the best book ever written on that deck of cards decorated with mysterious images called the tarot.”
Robert Place has been a frequent lecturer on and teacher of Western mysticism and the history and use of the tarot. Besides teaching regularly at the New York Open Center since 1996 and at the Metropolitan Museum of Art in New York since 2009, he has taught at the World Tarot Congress, in Chicago and in Dallas; the Southeast Tarot Congress, in Florida; the New York Reader's Studio; The Third International Conference of the Association for Esoteric Studies, in Charleston; The Omega Institute, in New York; The New York Theosophical Society; Columbia University; The Museo Dei Tarocchi, in Riola, Italy; The Tarot Guild of Australia, Melbourne; Cartomancia, in Sao Paulo, Brazil; and he has given workshops in Los Angeles, Salt Lake City, Las Vegas; and since 2017, in Beijing, Shanghai, and Hangzhou, China. His lectures have appeared on the BBC, the Learning Channel, Discovery, and A&E.
In July, 2007, Place had the honor of cutting the ribbon at the grand opening of the Museo dei Tarocchi, in Riola, Italy. Place was also the curator of an exhibition on the art and history of the tarot, which was held at the Los Angeles Craft and Folk Art Museum, from January 23, 2010, to May 9, 2010 and is the subject of his book, The Fools Journey: the History, Art, & Symbolism of the Tarot'. His facsimile of one of the earliest Italian Renaissance woodcut Tarots is included in the Metropolitan Museum of Art in New York. | 1 | Applied and Interdisciplinary Chemistry |
About 50 ml of concentrated (>12%) hydrogen peroxide is first mixed with liquid soap or dishwashing detergent. Then, a catalyst, often around 10 ml potassium iodide solution or catalase from baker's yeast, is added to make the hydrogen peroxide decompose very quickly. Hydrogen peroxide breaks down into oxygen and water. As a small amount of hydrogen peroxide generates a large volume of oxygen, the oxygen quickly pushes out of the container. The soapy water traps the oxygen, creating bubbles, and turns into foam. About 5-10 drops of food coloring could also be added before the catalyst to dramatize the effect. How rapidly the reaction occurs will depend on the concentration of hydrogen peroxide used. | 1 | Applied and Interdisciplinary Chemistry |
Medication is a medicine or a chemical compound used to treat or cure illness. According to Encyclopædia Britannica, medication is "a substance used in treating a disease or relieving pain".
As defined by the National Cancer Institute, dosage forms of medication can include tablets, capsules, liquids, creams, and patches. Medications can be given in different ways, such as by mouth, by infusion into a vein, or by drops put into the ear or eye. A medication that does not contain an active ingredient and is used in research studies is called a placebo.
In Europe, the term is "medicinal product", and it is defined by EU law as:
* "Any substance or combination of substances presented as having properties for treating or preventing disease in human beings; or"
* "Any substance or combination of substances which may be used in or administered to human beings either with a view to restoring, correcting or modifying physiological functions by exerting a pharmacological, immunological or metabolic action or to making a medical diagnosis."
In the US, a "drug" is:
* A substance (other than food) intended to affect the structure or any function of the body.
* A substance intended for use as a component of a medicine but not a device or a component, part, or accessory of a device.
* A substance intended for use in the diagnosis, cure, mitigation, treatment, or prevention of disease.
* A substance recognized by an official pharmacopeia or formulary.
* Biological products are included within this definition and are generally covered by the same laws and regulations, but differences exist regarding their manufacturing processes (chemical process versus biological process). | 1 | Applied and Interdisciplinary Chemistry |
Spin exchange optical pumping (SEOP) is one of several hyperpolarization techniques discussed on this page. This technique specializes in creating hyperpolarized (HP) noble gases, such as He, Xe, and quadrupolar Xe, Kr, and Ne. Noble gases are required because SEOP is performed in the gas phase, they are chemically inert, non-reactive, chemically stable with respect to alkali metals, and their T is long enough to build up polarization. Spin 1/2 noble gases meet all these requirements, and spin 3/2 noble gases do to an extent, although some spin 3/2 do not have a sufficient T. Each of these noble gases has their own specific application, such as characterizing lung space and tissue via in vivo molecular imaging and functional imaging of lungs, to study changes in metabolism of healthy versus cancer cells, or use as targets for nuclear physics experiments. During this process, circularly polarized infrared laser light, tuned to the appropriate wavelength, is used to excite electrons in an alkali metal, such as caesium or rubidium inside a sealed glass vessel. Infrared light is necessary because it contains the wavelengths necessary to excite the alkali metal electrons, although the wavelength necessary to excite sodium electrons is below this region (Table 1).
The angular momentum is transferred from the alkali metal electrons to the noble gas nuclei through collisions. Nitrogen is used as a quenching gas, which prevents the fluorescence of the polarized alkali metal, which would lead to de-polarization of the noble gas. If fluorescence was not quenched, the light emitted during relaxation would be randomly polarized, working against the circularly polarized laser light. While different sizes of glass vessels (also called cells), and therefore different pressures, are used depending on the application, one amagat of total pressure of noble gas and nitrogen is sufficient for SEOP and 0.1 amagat of nitrogen density is needed to quench fluorescence. Great improvements in Xe hyperpolarization technology have achieved > 50% level at flow rates of 1–2 L/min, which enables human clinical applications. | 0 | Theoretical and Fundamental Chemistry |
In decay, or positron emission, the weak interaction converts an atomic nucleus into a nucleus with atomic number decreased by one, while emitting a positron () and an electron neutrino (). decay generally occurs in proton-rich nuclei. The generic equation is:
This may be considered as the decay of a proton inside the nucleus to a neutron:
:p → n + +
However, decay cannot occur in an isolated proton because it requires energy, due to the mass of the neutron being greater than the mass of the proton. decay can only happen inside nuclei when the daughter nucleus has a greater binding energy (and therefore a lower total energy) than the mother nucleus. The difference between these energies goes into the reaction of converting a proton into a neutron, a positron, and a neutrino and into the kinetic energy of these particles. This process is opposite to negative beta decay, in that the weak interaction converts a proton into a neutron by converting an up quark into a down quark resulting in the emission of a or the absorption of a . When a boson is emitted, it decays into a positron and an electron neutrino: | 0 | Theoretical and Fundamental Chemistry |
Major developments: The chemical formula for gunpowder is recorded in the Wujing Zongyao by 1044. Bombs appear in the early 11th century. Gunpowder becomes more common in the Song dynasty and production of gunpowder weapons is systematized. The Song court restricts trade of gunpowder ingredients with the Liao and Western Xia dynasties. | 1 | Applied and Interdisciplinary Chemistry |
Anisomycin interferes with protein and DNA synthesis by inhibiting peptidyl transferase or the 80S ribosome system.
Anisomycin is also mentioned as a potential psychiatric drug, as it may inhibit the consolidation of new context-specific long-term memories, as well as long time consolidated memories rendered labile through reactivation.
Injection of anisomycin into the hippocampus has been proposed for selective removal of memories. | 1 | Applied and Interdisciplinary Chemistry |
An SNP array is a useful tool for studying slight variations between whole genomes. The most important clinical applications of SNP arrays are for determining disease susceptibility and for measuring the efficacy of drug therapies designed specifically for individuals. In research, SNP arrays are most frequently used for genome-wide association studies. Each individual has many SNPs. SNP-based genetic linkage analysis can be used to map disease loci, and determine disease susceptibility genes in individuals. The combination of SNP maps and high density SNP arrays allows SNPs to be used as markers for genetic diseases that have complex traits. For example, genome-wide association studies have identified SNPs associated with diseases such as rheumatoid arthritis and prostate cancer. A SNP array can also be used to generate a virtual karyotype using software to determine the copy number of each SNP on the array and then align the SNPs in chromosomal order.
SNPs can also be used to study genetic abnormalities in cancer. For example, SNP arrays can be used to study loss of heterozygosity (LOH). LOH occurs when one allele of a gene is mutated in a deleterious way and the normally-functioning allele is lost. LOH occurs commonly in oncogenesis. For example, tumor suppressor genes help keep cancer from developing. If a person has one mutated and dysfunctional copy of a tumor suppressor gene and his second, functional copy of the gene gets damaged, they may become more likely to develop cancer.
Other chip-based methods such as comparative genomic hybridization can detect genomic gains or deletions leading to LOH. SNP arrays, however, have an additional advantage of being able to detect copy-neutral LOH (also called uniparental disomy or gene conversion). Copy-neutral LOH is a form of allelic imbalance. In copy-neutral LOH, one allele or whole chromosome from a parent is missing. This problem leads to duplication of the other parental allele. Copy-neutral LOH may be pathological. For example, say that the mothers allele is wild-type and fully functional, and the fathers allele is mutated. If the mothers allele is missing and the child has two copies of the fathers mutant allele, disease can occur.
High density SNP arrays help scientists identify patterns of allelic imbalance. These studies have potential prognostic and diagnostic uses. Because LOH is so common in many human cancers, SNP arrays have great potential in cancer diagnostics. For example, recent SNP array studies have shown that solid tumors such as gastric cancer and liver cancer show LOH, as do non-solid malignancies such as hematologic malignancies, ALL, MDS, CML and others. These studies may provide insights into how these diseases develop, as well as information about how to create therapies for them.
Breeding in a number of animal and plant species has been revolutionized by the emergence of SNP arrays. The method is based on the prediction of genetic merit by incorporating relationships among individuals based on SNP array data. This process is known as genomic selection. Crop-specific arrays find use in agriculture. | 1 | Applied and Interdisciplinary Chemistry |
Dally works as a co-receptor of some secreted signaling molecules as fibroblast growth factor, vascular endothelial growth factor, hepatocyte growth factor and members of the Wnt signaling pathway, TGF-b and Hedgehog families. It is also necessary for the cell division patterning during the post-embryonic development of the nervous system.
It is a regulatory component of the Wg receptor and is part of a multiprotein complex together with Frizzled (Fz) transmembrane proteins. Therefore, it regulates two cell growth factors in Drosophila melanogaster, Wingless (Wg) and Decapentaplegic (Dpp). It must be said that in vertebrates the equivalent to Dpp are Bone Morphogenetic Proteins, and the mammalian equal to Wg might be integrin-beta 4. The first one (Wg) controls cell proliferation and differentiation during embryos development, specifically in epidermis, whereas the latter (Dpp) plays a role in the imaginal discs’ growth.
Dpp and Wg are mutually antagonistic in patterning genitalia. Concretely, dally selectively regulates both Wg signalling in epidermis and Dpp in genitalia. This selectivity is supposed to be controlled by the type of Glycosaminoglycan GAG bonded to the dally protein, considering that there is a huge structural variety in GAGs.
Tissue malformations occur in various situations. As said in the introduction, the sgl enzyme is essential for a normal biosynthesis of dally. That is why the absence or malfunction of this enzyme doesn’t allow the correct Wg and Dpp signalling. Also the expression of mutated dally proteins alters Wnt signalling pathways, which leads to anomalies in Drosophila melanogaster’s eye, antennal, genital, wing and neural morphogenesis. | 1 | Applied and Interdisciplinary Chemistry |
A radioactive tracer, radiotracer, or radioactive label is a synthetic derivative of a natural compound in which one or more atoms have been replaced by a radionuclide (a radioactive atom). By virtue of its radioactive decay, it can be used to explore the mechanism of chemical reactions by tracing the path that the radioisotope follows from reactants to products. Radiolabeling or radiotracing is thus the radioactive form of isotopic labeling. In biological contexts, experiments that use radioisotope tracers are sometimes called radioisotope feeding experiments.
Radioisotopes of hydrogen, carbon, phosphorus, sulfur, and iodine have been used extensively to trace the path of biochemical reactions. A radioactive tracer can also be used to track the distribution of a substance within a natural system such as a cell or tissue, or as a flow tracer to track fluid flow. Radioactive tracers are also used to determine the location of fractures created by hydraulic fracturing in natural gas production. Radioactive tracers form the basis of a variety of imaging systems, such as, PET scans, SPECT scans and technetium scans. Radiocarbon dating uses the naturally occurring carbon-14 isotope as an isotopic label. | 0 | Theoretical and Fundamental Chemistry |
Micromeritic properties of a particle, i.e. the particle size in a formulation, influence the physical stability of the suspensions and emulsions. The smaller the size of the particle, the better the physical stability of the dosage form owing to the Brownian motion of the particles in the dispersion. | 0 | Theoretical and Fundamental Chemistry |
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