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Silicon isotope biogeochemistry is the study of environmental processes using the relative abundance of Si isotopes. As the relative abundance of Si stable isotopes varies among different natural materials, the differences in abundance can be used to trace the source of Si, and to study biological, geological, and chemical processes. The study of stable isotope biogeochemistry of Si aims to quantify the different Si fluxes in the global biogeochemical silicon cycle, to understand the role of biogenic silica within the global Si cycle, and to investigate the applications and limitations of the sedimentary Si record as an environmental and palaeoceanographic proxy. | 0 | Theoretical and Fundamental Chemistry |
The engine is brought up to speed with the drive to the propeller engaged and with the Kitchen rudder in the "neutral" position. This is a position where an equal quantity of thrust is aimed forward and aft. Each vessel will have a unique "neutral" position. | 1 | Applied and Interdisciplinary Chemistry |
If the reaction equation is balanced, that does not mean that the reaction really occurs. The rate at which reactions occur depends on the energy and the flux of the incident particles, and the reaction cross section. An example of a large repository of reaction rates is the REACLIB database, as maintained by the Joint Institute for Nuclear Astrophysics. | 0 | Theoretical and Fundamental Chemistry |
Evidence suggests that manganese (Mn) was first incorporated into biological systems roughly 3.2–2.8 billion years ago, during the Archean Period. Together with calcium, it formed the manganese-calcium oxide complex (determined by X-ray diffraction) which consisted of a manganese cluster, essentially an inorganic cubane (cubical) structure. The incorporation of a manganese center in photosystem II was highly significant, as it allowed for photosynthetic oxygen evolution of plants. The oxygen-evolving complex (OEC) is a critical component of photosystem II contained in the thylakoid membranes of chloroplasts; it is responsible for terminal photooxidation of water during light reactions.
The incorporation of Mn in proteins allowed the complexes the ability to reduce reactive oxygen species in Mn-superoxide dismutase (MnSOD) and catalase, in electron transfer-dependent catalysis (for instance in certain class I ribonucleotide reductases) and in the oxidation of water by photosystem II (PSII), where the production of thiobarbituric acid-reactive substances is decreased. This is due to manganese's ability to reduce superoxide anion and hydroxyl radicals as well as its chain-breaking capacity. | 0 | Theoretical and Fundamental Chemistry |
The Algenol system which is being commercialized by BioFields in Puerto Libertad, Sonora, Mexico utilizes seawater and industrial exhaust to produce ethanol. Porphyridium cruentum also have shown to be potentially suitable for ethanol production due to its capacity for accumulating large amount of carbohydrates. | 1 | Applied and Interdisciplinary Chemistry |
Double layer interactions are relevant in a wide number of phenomena. These forces are responsible for swelling of clays. They may also be responsible for the stabilization of colloidal suspension and will prevent particle aggregation of highly charged colloidal particles in aqueous suspensions. At low salt concentrations, the repulsive double layer forces can become rather long-ranged, and may lead to structuring of colloidal suspensions and eventually to formation of colloidal crystals. Such repulsive forces may further induce blocking of surfaces during particle deposition. Double layer interactions are equally relevant for surfactant aggregates, and may be responsible to the stabilization of cubic phases made of spheroidal micelles or lamellar phases consisting of surfactant or lipid bilayers. | 0 | Theoretical and Fundamental Chemistry |
When capillary waves are also affected substantially by gravity, they are called gravity–capillary waves. Their dispersion relation reads, for waves on the interface between two fluids of infinite depth:
where is the acceleration due to gravity, and are the mass density of the two fluids . The factor in the first term is the Atwood number. | 1 | Applied and Interdisciplinary Chemistry |
Some coactivators indirectly regulate gene expression by binding to an activator and inducing a conformational change that then allows the activator to bind to the DNA enhancer or promoter sequence. Once the activator-coactivator complex binds to the enhancer, RNA polymerase II and other general transcription machinery are recruited to the DNA and transcription begins. | 1 | Applied and Interdisciplinary Chemistry |
Paired-end tags (PET) (sometimes "Paired-End diTags", or simply "ditags") are the short sequences at the 5’ and 3 ends of a DNA fragment which are unique enough that they (theoretically) exist together only once in a genome, therefore making the sequence of the DNA in between them available upon search (if full-genome sequence data is available) or upon further sequencing (since tag sites are unique enough to serve as primer annealing sites). Paired-end tags (PET) exist in PET libraries with the intervening DNA absent, that is, a PET "represents" a larger fragment of genomic or cDNA by consisting of a short 5 linker sequence, a short 5 sequence tag, a short 3 sequence tag, and a short 3' linker sequence. It was shown conceptually that 13 base pairs are sufficient to map tags uniquely. However, longer sequences are more practical for mapping reads uniquely. The endonucleases (discussed below) used to produce PETs give longer tags (18/20 base pairs and 25/27 base pairs) but sequences of 50–100 base pairs would be optimal for both mapping and cost efficiency. After extracting the PETs from many DNA fragments, they are linked (concatenated) together for efficient sequencing. On average, 20–30 tags could be sequenced with the Sanger method, which has a longer read length. Since the tag sequences are short, individual PETs are well suited for next-generation sequencing that has short read lengths and higher throughput. The main advantages of PET sequencing are its reduced cost by sequencing only short fragments, detection of structural variants in the genome, and increased specificity when aligning back to the genome compared to single tags, which involves only one end of the DNA fragment. | 1 | Applied and Interdisciplinary Chemistry |
The history of fluid mechanics is a fundamental strand of the history of physics and engineering. The study of the movement of fluids (liquids and gases) and the forces that act upon them dates back to pre-history. The field has undergone a continuous evolution, driven by human dependence on water, meteorological conditions and internal biological processes.
The success of early civilizations, can be attributed to developments in the understanding of water dynamics, allowing for the construction of canals and aqueducts for water distribution and farm irrigation, as well as maritime transport. Due to its conceptual complexity, most discoveries in this field relied almost entirely on experiments, at least until the development of advanced understanding of differential equations and computational methods. Significant theoretical contributions were made by notables figures like Archimedes, Johann Bernoulli and his son Daniel Bernoulli, Leonhard Euler, Claude-Louis Navier and Stokes, who developed the fundamental equations to describe fluid mechanics. Advancements in experimentation and computational methods have further propelled the field, leading to practical applications in more specialized industries ranging from aerospace to environmental engineering. Fluid mechanics has also been important for the study astronomical bodies and the dynamics of galaxies. | 1 | Applied and Interdisciplinary Chemistry |
Cefuroxime is active against many bacteria including susceptible strains of Staphylococci and Streptococci, as well as a range of gram negative organisms. As with the other cephalosporins, it is susceptible to beta-lactamase, although as a second-generation variety, it is less so. Hence, it may have greater activity against Haemophilus influenzae, Neisseria gonorrhoeae, and Lyme disease. Unlike other second-generation cephalosporins, cefuroxime can cross the blood–brain barrier.
A systematic review found high quality evidence that injecting the eye with cefuroxime after cataract surgery will lower the chance of developing endophthalmitis after surgery. | 0 | Theoretical and Fundamental Chemistry |
The journal was established as the Journal of the Chemical Society A: Inorganic, Physical, Theoretical in 1966. In 1972, the journal was divided into three separate journals: Journal of the Chemical Society, Dalton Transactions (covering inorganic and organometallic chemistry), Journal of the Chemical Society, Faraday Transactions 1: Physical Chemistry in Condensed Phases, and Journal of the Chemical Society, Faraday Transactions 2: Molecular and Chemical Physics. The journal obtained its current name in 2003. In January 2000, Acta Chemica Scandinavica was absorbed.
The Journal of the Chemical Society, Dalton Transactions was published as 12 issues a year from 1972. As submissions increased, the journal switched to 24 issues a year in 1992 and then to 48 issues a year in 2006.
In 2010, the journal introduced a sequential volume numbering scheme, with one volume per year. While volume numbers were not assigned retro-actively, the first issue of 2010 was assigned volume 39 (2010 being the 39th year since the establishment of the Journal of the Chemical Society, Dalton Transactions. | 0 | Theoretical and Fundamental Chemistry |
One category of reactions under Curtin–Hammett control includes transformations in which the more stable conformer reacts more quickly. This occurs when the transition state from the major intermediate to its respective product is lower in energy than the transition state from the minor intermediate to the other possible product. The major product is then derived from the major conformer, and the product distribution does not mirror the equilibrium conformer distribution. | 0 | Theoretical and Fundamental Chemistry |
The journal covers developments in fundamental and applied research into science related to clinical laboratories. It covers areas such as clinical biochemistry, molecular medicine, hematology, immunology, microbiology, virology, drug measurement, genetic epidemiology, evaluation of diagnostic markers, new reagents and systems, reference materials, and reference values. It also publishes recommendations and news from the International Federation of Clinical Chemistry and Laboratory Medicine and the European Federation of Clinical Chemistry and Laboratory Medicine. | 1 | Applied and Interdisciplinary Chemistry |
The enzymatic process that produces heme is properly called porphyrin synthesis, as all the intermediates are tetrapyrroles that are chemically classified as porphyrins. The process is highly conserved across biology. In humans, this pathway serves almost exclusively to form heme. In bacteria, it also produces more complex substances such as cofactor F430 and cobalamin (vitamin B).
The pathway is initiated by the synthesis of δ-aminolevulinic acid (dALA or δALA) from the amino acid glycine and succinyl-CoA from the citric acid cycle (Krebs cycle). The rate-limiting enzyme responsible for this reaction, ALA synthase, is negatively regulated by glucose and heme concentration. Mechanism of inhibition of ALAs by heme or hemin is by decreasing stability of mRNA synthesis and by decreasing the intake of mRNA in the mitochondria. This mechanism is of therapeutic importance: infusion of heme arginate or hematin and glucose can abort attacks of acute intermittent porphyria in patients with an inborn error of metabolism of this process, by reducing transcription of ALA synthase.
The organs mainly involved in heme synthesis are the liver (in which the rate of synthesis is highly variable, depending on the systemic heme pool) and the bone marrow (in which rate of synthesis of Heme is relatively constant and depends on the production of globin chain), although every cell requires heme to function properly. However, due to its toxic properties, proteins such as emopexin (Hx) are required to help maintain physiological stores of iron in order for them to be used in synthesis. Heme is seen as an intermediate molecule in catabolism of hemoglobin in the process of bilirubin metabolism. Defects in various enzymes in synthesis of heme can lead to group of disorder called porphyrias, which include acute intermittent porphyria, congenital erythropoetic porphyria, porphyria cutanea tarda, hereditary coproporphyria, variegate porphyria, and erythropoietic protoporphyria. | 1 | Applied and Interdisciplinary Chemistry |
The duplication and transmission of genetic material from one generation of cells to the next is the basis for molecular inheritance and the link between the classical and molecular pictures of genes. Organisms inherit the characteristics of their parents because the cells of the offspring contain copies of the genes in their parents' cells. In asexually reproducing organisms, the offspring will be a genetic copy or clone of the parent organism. In sexually reproducing organisms, a specialized form of cell division called meiosis produces cells called gametes or germ cells that are haploid, or contain only one copy of each gene. The gametes produced by females are called eggs or ova, and those produced by males are called sperm. Two gametes fuse to form a diploid fertilized egg, a single cell that has two sets of genes, with one copy of each gene from the mother and one from the father.
During the process of meiotic cell division, an event called genetic recombination or crossing-over can sometimes occur, in which a length of DNA on one chromatid is swapped with a length of DNA on the corresponding homologous non-sister chromatid. This can result in reassortment of otherwise linked alleles. The Mendelian principle of independent assortment asserts that each of a parent's two genes for each trait will sort independently into gametes; which allele an organism inherits for one trait is unrelated to which allele it inherits for another trait. This is in fact only true for genes that do not reside on the same chromosome or are located very far from one another on the same chromosome. The closer two genes lie on the same chromosome, the more closely they will be associated in gametes and the more often they will appear together (known as genetic linkage). Genes that are very close are essentially never separated because it is extremely unlikely that a crossover point will occur between them. | 1 | Applied and Interdisciplinary Chemistry |
Plastids are thought to be descended from endosymbiotic cyanobacteria. The primary endosymbiotic event of the Archaeplastida is hypothesized to have occurred around 1.5 billion years ago and enabled eukaryotes to carry out oxygenic photosynthesis. Three evolutionary lineages in the Archaeplastida have since emerged in which the plastids are named differently: chloroplasts in green algae and/or plants, rhodoplasts in red algae, and muroplasts in the glaucophytes. The plastids differ both in their pigmentation and in their ultrastructure. For example, chloroplasts in plants and green algae have lost all phycobilisomes, the light harvesting complexes found in cyanobacteria, red algae and glaucophytes, but instead contain stroma and grana thylakoids. The glaucocystophycean plastid—in contrast to chloroplasts and rhodoplasts—is still surrounded by the remains of the cyanobacterial cell wall. All these primary plastids are surrounded by two membranes.
The plastid of photosynthetic Paulinella species is often referred to as the cyanelle or chromatophore, and had a much more recent endosymbiotic event about 90–140 million years ago; it is the only known primary endosymbiosis event of cyanobacteria outside of the Archaeplastida. The plastid belongs to the "PS-clade" (of the cyanobacteria genera Prochlorococcus and Synechococcus), which is a different sister clade to the plastids belonging to the Archaeplastida.
In contrast to primary plastids derived from primary endosymbiosis of a prokaryoctyic cyanobacteria, complex plastids originated by secondary endosymbiosis in which a eukaryotic organism engulfed another eukaryotic organism that contained a primary plastid. When a eukaryote engulfs a red or a green alga and retains the algal plastid, that plastid is typically surrounded by more than two membranes. In some cases these plastids may be reduced in their metabolic and/or photosynthetic capacity. Algae with complex plastids derived by secondary endosymbiosis of a red alga include the heterokonts, haptophytes, cryptomonads, and most dinoflagellates (= rhodoplasts). Those that endosymbiosed a green alga include the euglenids and chlorarachniophytes (= chloroplasts). The Apicomplexa, a phylum of obligate parasitic alveolates including the causative agents of malaria (Plasmodium spp.), toxoplasmosis (Toxoplasma gondii), and many other human or animal diseases also harbor a complex plastid (although this organelle has been lost in some apicomplexans, such as Cryptosporidium parvum, which causes cryptosporidiosis). The apicoplast is no longer capable of photosynthesis, but is an essential organelle, and a promising target for antiparasitic drug development.
Some dinoflagellates and sea slugs, in particular of the genus Elysia, take up algae as food and keep the plastid of the digested alga to profit from the photosynthesis; after a while, the plastids are also digested. This process is known as kleptoplasty, from the Greek, kleptes (), thief. | 0 | Theoretical and Fundamental Chemistry |
In the laboratory, cobalt(II) chloride serves as a common precursor to other cobalt compounds. Generally, diluted aqueous solutions of the salt behave like other cobalt(II) salts since these solutions consist of the ion regardless of the anion. For example, such solutions give a precipitate of cobalt sulfide upon treatment with hydrogen sulfide . | 0 | Theoretical and Fundamental Chemistry |
Solvophoresis is a spontaneous motion of dispersed particles in a mixed solvent induced by a gradient of solvent concentration. Solvophoresis was experimentally established by Marek Kosmulski and Egon Matijevic. Solvophoresis is similar to diffusiophoresis. | 0 | Theoretical and Fundamental Chemistry |
A telluroketone is an analog of a ketone in which the oxygen atom has been replaced by a tellurium atom. This change makes the functional group less stable, requiring greater steric and electronic stabilization. | 0 | Theoretical and Fundamental Chemistry |
YcaO is a protein found in bacteria which is involved in the synthesis of thiazole/oxazole modified microcin antibiotics, such as bottromycin. YcaO performs ATP dependent cyclodehydration to form the oxazole and thiazole moieties of the microcin.
The YcaO name origin is from a gene naming rubric that was established from the bacterium Escherichia coli. If a gene has an unknown function, it was given a four-letter name starting with the letter Y and the next three letters are given based on the genomic location.
Methyl coenzyme M reductase (MCR) or Coenzyme-B sulfoethylthiotransferase is a protein known in thioamidation (a posttranslational modification). A Ycao enzyme dependent on ATP is needed for MCR thioamidation as well as a sulfide source. YcaO enzymes are needed to catalyze the ATP-dependent backbone cyclodehydration of polar amino acids such as Cysteine, Serine, and Threonine to the correct thiazoline and (methyl) oxazoline Heterocycle. The side chains of these amino acids can act as Nucleophiles. The Thiol group in cysteine and the hydroxyl group of serine and threonine are strong nucleophiles. | 1 | Applied and Interdisciplinary Chemistry |
The enthalpies of formation of some Donor-I adducts are listed below. I is a Lewis acid classified as a soft acid and its acceptor properties are discussed in the ECW model. The relative acceptor strength of I toward a series of bases, versus other Lewis acids, can be illustrated by C-B plots. | 0 | Theoretical and Fundamental Chemistry |
Addition of achiral allylmetals to aldehydes forms a chiral alcohol, the stereochemical outcome of this reaction is determined by the chirality of the α-carbon on the aldehyde substrate (Figure "Substrate control: addition of achiral allylmetals to α-chiral aldehydes"). The allylmetal reagents used include boron, tin and titanium.
Cram’s rule explains the stereoselectivity by considering the transition state depicted in figure 3. In the transition state the oxygen lone pair is able to interact with the boron centre whilst the allyl group is able to add to the carbon end of the carbonyl group. The steric demand of this transition state is minimized by the α-carbon configuration holding the largest group away from (trans to) the congested carbonyl group and the allylmetal group approaching past the smallest group on the α-carbon centre. In the example below (Figure "An example of substrate controlled addition of achiral allyl-boron to α-chiral aldehyde"), (R)-2-methylbutanal (1) reacts with the allylboron reagent (2) with two possible diastereomers of which the (R, R)-isomer is the major product. The Cram model of this reaction is shown with the carbonyl group placed trans to the ethyl group (the large group) and the allyl boron approaching past the hydrogen (the small group). The structure is shown in Newman projection. In this case the nucleophilic addition reaction happens at the face where the hydrogen (the small group) is, producing the (R, R)-isomer as the major product. | 0 | Theoretical and Fundamental Chemistry |
A 2022 study by researchers from the Mayo Clinic, Maastricht University, and Ethris GmBH, a biotech company that focuses on RNA therapeutics, found that chemically modified mRNA encoding BMP-2 promoted dosage-dependent healing of femoral osteotomies in male rats. The mRNA molecules were complexed within nonviral lipid particles, loaded onto sponges, and surgically implanted into the bone defects. They remained localized around the site of application. Compared to receiving rhBMP-2 directly, bony tissues regenerated after mRNA treatment displayed superior strength and less formation of massive callus. | 1 | Applied and Interdisciplinary Chemistry |
The George E. Davis Medal is a medal of the IChemE given not more frequently than every three years, for achievements in chemical engineering. It is named after George E. Davis. | 1 | Applied and Interdisciplinary Chemistry |
Major developments: Gunpowder is utilized in Chinese warfare and an assortment of gunpowder weapons appear. Fire arrows utilizing gunpowder as an incendiary appear in the early 900s and possibly rocket arrows as well by the end of the century. The gunpowder slow match is used for igniting flame throwers. The ancestor of firearms, the fire lance, also appears, but its usage in the 10th century is uncertain and no textual evidence for it exists during this period. | 1 | Applied and Interdisciplinary Chemistry |
Sonication has numerous effects, both chemical and physical. The scientific field concerned with understanding the effect of sonic waves on chemical systems is called sonochemistry. The chemical effects of ultrasound do not come from a direct interaction with molecular species. Studies have shown that no direct coupling of the acoustic field with chemical species on a molecular level can account for sonochemistry or sonoluminescence. Instead, in sonochemistry the sound waves migrate through a medium, inducing pressure variations and cavitations that grow and collapse, transforming the sound waves into mechanical energy. | 1 | Applied and Interdisciplinary Chemistry |
Indenyl like effects are also observed in a number of non indenyl substituted metal complexes. In fluorenyl complexes, associative substitution is enhanced even further than indenyl compounds. The substitution rate of Mn(η-CH)(CO) is about 60 times faster than that of Mn(η-CH)(CO)
Veiros conducted a study comparing the rate of substitution on [(η-X)Mn(CO)] where X is cyclopentadienyl, indenyl, fluorenyl, cyclohexadienyl, and 1-hydronaphthalene. Unsurprisingly, it was found that the ease of η to η haptotropic shift correlated to the strength of the Mn-X bond. | 0 | Theoretical and Fundamental Chemistry |
Numerous studies have been dedicated towards the development of effective methods to enable cardiac tissue regeneration in patients after ischemic heart disease. An emerging approach to answer the problems related to ischemic tissue repair is through the use of stem cell-based therapy. However, the actual mechanism due to which this stem cell-based therapy has generative effects on cardiac function is still under investigation. Even though numerous methods have been studied for cell administration, the efficiency of the number of cells retained in the beating heart after implantation is still very low. A promising approach to overcome this problem is through the use of cell microencapsulation therapy which has shown to enable a higher cell retention as compared to the injection of free stem cells into the heart.
Another strategy to improve the impact of cell based encapsulation technique towards cardiac regenerative applications is through the use of genetically modified stem cells capable of secreting angiogenic factors such as vascular endothelial growth factor (VEGF) which stimulate neovascularization and restore perfusion in the damaged ischemic heart. An example of this is shown in the study by Zang et al. where genetically modified xenogeneic CHO cells expressing VEGF were encapsulated in alginate-polylysine-alginate microcapsules and implanted into rat myocardium. It was observed that the encapsulation protected the cells from an immunoresponse for three weeks and also led to an improvement in the cardiac tissue post-infarction due to increased angiogenesis. | 1 | Applied and Interdisciplinary Chemistry |
Another type of topographic contrast, extinction contrast, is slightly more complex. While the two above variants are explicable in simple terms based on geometrical theory (basically, the Bragg law) or kinematical theory of X-ray diffraction, extinction contrast can be understood based on dynamical theory.
Qualitatively, extinction contrast arises e.g. when the thickness of a sample, compared to the respective extinction length (Bragg case) or Pendelloesung length (Laue case), changes across the image. In this case, diffracted beams from areas of different thickness, having suffered different degrees of extinction, are recorded within the same image, giving rise to contrast. Topographists have systematically investigated this effect by studying wedge-shaped samples, of linearly varying thickness, allowing to directly record in one image the dependence of diffracted intensity on sample thickness as predicted by dynamical theory.
In addition to mere thickness changes, extinction contrast also arises when parts of a crystal are diffracting with different strengths, or when the crystal contains deformed (strained) regions.
The governing quantity for an overall theory of extinction contrast in deformed crystals is called the effective misorientation
where is the displacement vector field, and and are the directions of the incident and diffracted beam, respectively.
In this way, different kinds of disturbances are "translated" into equivalent misorientation values, and contrast formation can be understood analogously to orientation contrast.
For instance, a compressively strained material requires larger Bragg angles for diffraction at unchanged wavelength. To compensate for this and to reach diffraction conditions, the sample needs to be rotated, similarly as in the case of lattice tilts.
A simplified and more "transparent" formula taking into account the combined effect of tilts and strains onto contrast is the following: | 0 | Theoretical and Fundamental Chemistry |
Photoactivated guanylyl cyclases have been discovered in the aquatic fungi Blastocladiella emersonii and Catenaria anguillulae. Unlike PACs, these light-activated cyclases use retinal as their light sensor and are therefore rhodopsin guanylyl cyclases (RhGC). When expressed in Xenopus oocytes or mammalian neurons, RhGCs generate cGMP in response to green light. Therefore, they are considered useful optogenetic tools to investigate cGMP signaling. | 1 | Applied and Interdisciplinary Chemistry |
All eukaryotes use G proteins for signaling and have evolved a large diversity of G proteins. For instance, humans encode 18 different G proteins, 5 G proteins, and 12 G proteins. | 1 | Applied and Interdisciplinary Chemistry |
There are various organizations founded for the purpose of storing and analyzing DNA sample. For example; The UK Biobank contains DNA samples of 500,000 individuals aged between 40 and 69 when their samples were taken in the years 2006-2010 . The Human DNA Bank India at Lucknow city, the Asias first [https://www.dnaindia.com/india/report-asia-s-first-human-dna-bank-comes-up-in-lucknow-1170426 Human DNA Bank] takes the DNA of common public, stores it for 50 years, takes their biometrics as well and provide them a UID DNA card. This system is an absolute mean of identity and is very helpful for the concerned associations in many conditions like identification at any mass gathering, identification at any massive calamity, identification at terrorist attacks, identification of any individual even if they are hiding their real identity.[https://www.rediff.com/news/2008/jun/15bank.htm] [https://timesofindia.indiatimes.com/city/lucknow/Lucknow-to-have-Indias-first-DNA-bank/articleshow/2328412.cms] The director Dr. Saeed Ahmad has established [https://www.outlookindia.com/magazine/story/indias-biodata/239077 Asias first human DNA bank] in India and has been well known throughout the world for his work on DNA. Under IQRA Biotech Services this human DNA bank which is in public-privet-partnership with Biotech Park, Lucknow under the Department of Biotechnology and the Ministry of Science and Technology. IQRA Biotech Services has also established a cord blood and stem cell bank that stores the stem cells of their clients and in future it is possible that these stem cells may be used for genetic treatments of diseases like spinal cord injuries, neuralgic palsy, leukemia, Parkinson's disease, anemia, SCIA, and cancer. | 1 | Applied and Interdisciplinary Chemistry |
In addition to the specialisation factories have for the type of RNA polymerase they contain, there is a further level of specialisation present. There are some factories that only transcribe a certain set of related genes, this further strengthens the concept that the main function of a transcription factory is for transcriptional efficiency. | 1 | Applied and Interdisciplinary Chemistry |
The names of esters that are formed from an alcohol and an acid, are derived from the parent alcohol and the parent acid, where the latter may be organic or inorganic. Esters derived from the simplest carboxylic acids are commonly named according to the more traditional, so-called "trivial names" e.g. as formate, acetate, propionate, and butyrate, as opposed to the IUPAC nomenclature methanoate, ethanoate, propanoate, and butanoate. Esters derived from more complex carboxylic acids are, on the other hand, more frequently named using the systematic IUPAC name, based on the name for the acid followed by the suffix -oate. For example, the ester hexyl octanoate, also known under the trivial name hexyl caprylate, has the formula .
The chemical formulas of organic esters formed from carboxylic acids and alcohols usually take the form or RCOOR, where R and R are the organyl parts of the carboxylic acid and the alcohol, respectively, and R can be a hydrogen in the case of esters of formic acid. For example, butyl acetate (systematically butyl ethanoate), derived from butanol and acetic acid (systematically ethanoic acid) would be written . Alternative presentations are common including BuOAc and .
Cyclic esters are called lactones, regardless of whether they are derived from an organic or inorganic acid. One example of an organic lactone is γ-valerolactone. | 0 | Theoretical and Fundamental Chemistry |
Beta decay can be considered as a perturbation as described in quantum mechanics, and thus Fermi's Golden Rule can be applied. This leads to an expression for the kinetic energy spectrum of emitted betas as follows:
where is the kinetic energy, is a shape function that depends on the forbiddenness of the decay (it is constant for allowed decays), is the Fermi Function (see below) with Z the charge of the final-state nucleus, is the total energy, is the momentum, and is the Q value of the decay. The kinetic energy of the emitted neutrino is given approximately by minus the kinetic energy of the beta.
As an example, the beta decay spectrum of Bi (originally called RaE) is shown to the right. | 0 | Theoretical and Fundamental Chemistry |
For the case of a sphere in a uniform far field flow, it is advantageous to use a cylindrical coordinate system . The –axis is through the centre of the sphere and aligned with the mean flow direction, while is the radius as measured perpendicular to the –axis. The origin is at the sphere centre. Because the flow is axisymmetric around the –axis, it is independent of the azimuth .
In this cylindrical coordinate system, the incompressible flow can be described with a Stokes stream function , depending on and :
with and the flow velocity components in the and direction, respectively. The azimuthal velocity component in the –direction is equal to zero, in this axisymmetric case. The volume flux, through a tube bounded by a surface of some constant value , is equal to and is constant.
For this case of an axisymmetric flow, the only non-zero component of the vorticity vector is the azimuthal –component
The Laplace operator, applied to the vorticity , becomes in this cylindrical coordinate system with axisymmetry:
From the previous two equations, and with the appropriate boundary conditions, for a far-field uniform-flow velocity in the –direction and a sphere of radius , the solution is found to be
The solution of velocity in cylindrical coordinates and components follows as:
The solution of vorticity in cylindrical coordinates follows as:
The solution of pressure in cylindrical coordinates follows as:
The solution of pressure in spherical coordinates follows as:
The formula of pressure is also called dipole potential analogous to the concept in electrostatics.
A more general formulation, with arbitrary far-field velocity-vector , in cartesian coordinates follows with:
In this formulation the non-conservative term represents a kind of so-called Stokeslet. The Stokeslet is the Green's function of the Stokes-Flow-Equations. The conservative term is equal to the dipole gradient field. The formula of vorticity is analogous to the Biot–Savart law in electromagnetism.
The following formula describes the viscous stress tensor for the special case of Stokes flow. It is needed in the calculation of the force acting on the particle. In Cartesian coordinates the vector-gradient is identical to the Jacobian matrix. The matrix represents the identity-matrix.
The force acting on the sphere is to calculate by surface-integral, where represents the radial unit-vector of spherical-coordinates: | 1 | Applied and Interdisciplinary Chemistry |
The H. G. Smith Memorial Award is the premier award of the RACI. It is awarded annually to a member who has contributed most to the development of some branch of chemical science, judged by research work published or accepted for publication during the ten years (or equivalent relative to opportunity) preceding the award. The recipient is required to be a current member for a minimum of 3 years. If in the opinion of the RACI Board there is no candidate who has sufficient merit, the Board may refrain from making an award. Notable recipients of the award include:
* David Rivett (inaugural recipient in 1929)
* James Arthur Prescott (1931)
* Edward Sydney Simpson (1932)
* Ian William Wark (1933)
* Francis Patrick Dwyer (1943)
* John Stuart Anderson (1944)
* Martina Stenzel (2017) | 1 | Applied and Interdisciplinary Chemistry |
The good quantum numbers for a diatomic molecule, as well as good approximations of rotational energy levels, can be obtained by modeling the molecule using Hund's cases. | 0 | Theoretical and Fundamental Chemistry |
Fluorenylidene can be produced by photolysis of 9-diazofluorene (DAF).
Ultra-fast (300 fs) time resolved laser-flash photolysis of DAF implicates a four-step process in the formation of fluorenylidene by irradiation of 9-diazofluorene.
# Irradiation of DAF initially yields an excited singlet state diazofluorene molecule ( DAF*)
# DAF* decays to form the open shell carbene,FL*, as the minor product, and the less energetic closed shell carbene, FL, as the major product.
# Any excited singlet FL* in solution relaxes to the lower energy singlet state FL (20.9 ps)
# FL equilibrates with the ground state triplet FL by intersystem crossing. | 0 | Theoretical and Fundamental Chemistry |
Complex glycans possess a multitude of overlapping signals, especially in a proton spectrum. Therefore, it is advantageous to utilize 2D experiments for the assignment of signals.
The table and figures below list most widespread NMR techniques used in carbohydrate studies. | 0 | Theoretical and Fundamental Chemistry |
Barium is formed in large amounts by the fission process. A short-lived barium isotope was confused with radium by some early workers. They were bombarding uranium with neutrons in an attempt to form a new element. But instead they caused fission which generated a large amount of radioactivity in the target. Because the chemistry of barium and radium the two elements could be coseparated by for instance a precipitation with sulfate anions. Because of this similarity of their chemistry the early workers thought that the very radioactive fraction which was separated into the "radium" fraction contained a new isotope of radium. Some of this early work was done by Otto Hahn and Fritz Strassmann. | 0 | Theoretical and Fundamental Chemistry |
Bernoullis principle is a key concept in fluid dynamics that relates pressure, speed and height. Bernoullis principle states that an increase in the speed of a fluid occurs simultaneously with a decrease in static pressure or the fluids potential energy. The principle is named after the Swiss mathematician and physicist Daniel Bernoulli, who published it in his book Hydrodynamica in 1738. Although Bernoulli deduced that pressure decreases when the flow speed increases, it was Leonhard Euler in 1752 who derived Bernoullis equation in its usual form.
Bernoulli's principle can be derived from the principle of conservation of energy. This states that, in a steady flow, the sum of all forms of energy in a fluid is the same at all points that are free of viscous forces. This requires that the sum of kinetic energy, potential energy and internal energy remains constant. Thus an increase in the speed of the fluid—implying an increase in its kinetic energy—occurs with a simultaneous decrease in (the sum of) its potential energy (including the static pressure) and internal energy. If the fluid is flowing out of a reservoir, the sum of all forms of energy is the same because in a reservoir the energy per unit volume (the sum of pressure and gravitational potential ) is the same everywhere.
Bernoullis principle can also be derived directly from Isaac Newtons second Law of Motion. If a small volume of fluid is flowing horizontally from a region of high pressure to a region of low pressure, then there is more pressure behind than in front. This gives a net force on the volume, accelerating it along the streamline.
Fluid particles are subject only to pressure and their own weight. If a fluid is flowing horizontally and along a section of a streamline, where the speed increases it can only be because the fluid on that section has moved from a region of higher pressure to a region of lower pressure; and if its speed decreases, it can only be because it has moved from a region of lower pressure to a region of higher pressure. Consequently, within a fluid flowing horizontally, the highest speed occurs where the pressure is lowest, and the lowest speed occurs where the pressure is highest.
Bernoullis principle is only applicable for isentropic flows: when the effects of irreversible processes (like turbulence) and non-adiabatic processes (e.g. thermal radiation) are small and can be neglected. However, the principle can be applied to various types of flow within these bounds, resulting in various forms of Bernoullis equation. The simple form of Bernoullis equation is valid for incompressible flows (e.g. most liquid flows and gases moving at low Mach number). More advanced forms may be applied to compressible flows at higher Mach numbers. | 1 | Applied and Interdisciplinary Chemistry |
When a soap bubble is in contact with a solid or a liquid surface wetting is observed. On a solid surface, the contact angle of the bubble depends on the surface energy of the solid., A soap bubble has a larger contact angle on a solid surface displaying ultrahydrophobicity than on a hydrophilic surface – see Wetting. On a liquid surface, the contact angle of the soap bubble depends on its size - smaller bubbles have lower contact angles. | 1 | Applied and Interdisciplinary Chemistry |
Prior to World War I, work on synthetic organic chemistry in the United States had been quite limited, and most of the reagents used in laboratories had to be imported from Europe. When export stoppages and trade embargoes cut off this source, Clarence Derick, a professor of chemistry at University of Illinois at Urbana-Champaign, began an effort to synthesize these needed chemicals in industrial quantities in a university laboratory with the help of a few graduate students. This work was performed during the summer break and came to be known as the "summer prep". Students who worked in the laboratory were paid and received credit.
The basic procedures were often obtained from textbooks, and the procedures were sketchy. Reproducibility was important in summer preps, so students were required to keep meticulous record books. The procedures were finally collected and published for the first time in a four-pamphlet set called Organic Chemical Reagents, which quickly sold out. The publishers received submissions from other chemists, which spawned the idea for serial publication, and the first annual volume of Organic Syntheses was thus published in 1921. By then, chemists from other universities and industry were also contributing.
One example of much needed chemicals were dyes for sensitizing photographic film. Research efforts in this field led to the foundation of Eastman Kodak Organic Chemicals Division.
The summer preps contributed to the war effort in World War II but were discontinued in 1950 because by then an infrastructure of chemical companies with their own research had been established.
Until 1998, Organic Syntheses was published only as an annual printed volume. In that year, all past volumes were made available on an open access website and new articles are now published online as soon as they are accepted. | 0 | Theoretical and Fundamental Chemistry |
Frequency modulation atomic force microscopy, introduced by Albrecht, Grütter, Horne and Rugar in 1991,
is a mode of nc-AFM where the change in resonant frequency of the sensor is tracked directly, by always exciting the sensor on resonance. To maintain excitation on resonance the electronics must keep a 90° phase difference between the excitation and response of the sensor. This is either done by driving the sensor with the deflection signal phase shifted by 90°, or by using an advanced phase-locked loop which can lock to a specific phase. The microscope can then use the change in resonant frequency (f) as the SPM reference channel, either in feedback mode, or it can be recorded directly in constant height mode.
While recording frequency-modulated images, an additional feedback loop is normally used to keep the amplitude of resonance constant, by adjusting the drive amplitude. By recording the drive amplitude during the scan (usually referred to as the damping channel as the need for a higher drive amplitude corresponds to more damping in the system) a complementary image is recorded showing only non-conservative forces. This allows conservative and non-conservative forces in the experiment to be separated. | 0 | Theoretical and Fundamental Chemistry |
In November 2005 expert evidence was submitted to the High Court in London by the mothers of thirty children who claimed that during their pregnancies they were exposed to contamination from the waste removal operations and who sought to bring a legal action to try to prove a link between the mismanagement of the toxic waste and the birth defects suffered by their children. The evidence presented included reports detailing the higher rate of birth defects, and alleging that exposure to the toxic waste was the likely cause of the children's deformities. They also presented a report written by Roger Braithwaite, an environmental expert instructed by the families, which concluded that the negligent handling of the waste by Corby Borough Council demonstrated "naivety, arrogance, ignorance, incompetence and a possible serious conflict of interest... At this early stage it would seem to me that these... badly polluted lands have never been effectively or comprehensively assessed, properly permitted, regulated, monitored or adequate records maintained... This is environmental negligence on a grand scale."
After reviewing the evidence presented by all parties to the case, an order approved by the then Lord Chief Justice, Lord Phillips of Worth Matravers, set out the terms of the litigation in relation to the council's management and execution of the "land reclamation contracts" between 1985 and 1999 and any duty they had to the families, and permission was given for the parents to pursue the claim against Corby Borough Council as a class action involving children born between 1985 and 1999. | 1 | Applied and Interdisciplinary Chemistry |
The regulation of Snf3 in S. cerevisiae and its downstream events are still poorly understood, but it seems clear that a second glucose sensor Rgt2 influences Snf3 and vice versa. Furthermore, it is unclear whether these two proteins sense the glucose concentration on the outside or inside the cell. Snf3 and Rgt2 influence directly or indirectly several Hxt-transporters which are responsible for the glucose uptake. Low extracellular glucose concentrations are sensed by the Snf3 protein which probably leads to the expression of Hxt2-Genes for high affinity glucose transporters, while Rgt2 senses high glucose concentrations and leads to the expression of low affinity glucose transporters, like Hxt1 Although the downstream pathway is poorly understood it seems that Snf3 and Rgt2 transmit a signal directly or indirectly to Grr1, the DNA binding protein Rgt1, and the two cofactors Ssn6 and Tup1. Also needed for the transcription are the two nuclear proteins Mth1 and Std1. | 1 | Applied and Interdisciplinary Chemistry |
The MCHO group is planar. A C=O double bond is indicated by X-ray crystallography. A second resonance structure has a M=C double bond, with negative charge on oxygen. | 0 | Theoretical and Fundamental Chemistry |
An alternative preparation of Grignard reagents involves transfer of Mg from a preformed Grignard reagent to an organic halide. Other organomagnesium reagents are used as well. This method offers the advantage that the Mg transfer tolerates many functional groups. An illustrative reaction involves isopropylmagnesium chloride and aryl bromide or iodides: | 0 | Theoretical and Fundamental Chemistry |
Most processed polymer mixes consist of a dispersed phase in a more continuous matrix of the other component. The formation, size, and concentration of this disperse phase are typically optimized for specific mechanical properties. If the morphology is not stabilized, the dispersed phase may coalesce under heat or stress from the environment or further processing. This coalescence may result in diminished properties (brittleness and discoloration) due to the induced phase separation. These morphologies can be stabilized by sufficient interfacial adhesion or lowered interfacial tension between the two phases.
A common technique involves functionalizing one monomer. For example, Nylon-rubber bands are polymerized with functionalized rubber to produce graft or block copolymers. The added structures make it no longer favorable to coalesce and/or increase the steric hindrance in the interfacial area where phase separation would occur. | 0 | Theoretical and Fundamental Chemistry |
Supercritical water oxidation uses supercritical water as a medium in which to oxidize hazardous waste, eliminating production of toxic combustion products that burning can produce.
The waste product to be oxidised is dissolved in the supercritical water along with molecular oxygen (or an oxidising agent that gives up oxygen upon decomposition, e.g. hydrogen peroxide) at which point the oxidation reaction occurs. | 0 | Theoretical and Fundamental Chemistry |
Oxaziridine derivatives were first reported in the mid-1950s by Emmons and subsequently by Krimm and Horner and Jürgens. Whereas oxygen and nitrogen typically act as nucleophiles due to their high electronegativity, oxaziridines allow for electrophilic transfer of both heteroatoms. This unusual reactivity is due to the presence of the highly strained three membered ring and the relatively weak N-O bond. Nucleophiles tend to attack at the aziridine nitrogen when the nitrogen substituent is small (R= H), and at the oxygen atom when the nitrogen substituent has greater steric bulk. The unusual electronics of the oxaziridine system may be exploited to perform a number of oxygen and nitrogen transfer reactions including, but not limited to: α-hydroxylation of enolates, epoxidation of alkenes, selective oxidation of sulfides and selenides, amination of N-nucleophiles and N-acylamidation.
The peroxide process for the industrial production of hydrazine through the oxidation of ammonia with hydrogen peroxide in the presence of ketones was developed in the early 1970s.
Chiral camphorsulfonyloxaziridines proved useful in the syntheses of complex products, such as taxol which is marketed as a chemotherapy agent. Both the Holton Taxol total synthesis and the Wender Taxol total synthesis feature asymmetric α-hydroxylation with camphorsulfonyloxaziridine. | 0 | Theoretical and Fundamental Chemistry |
Atoms that have an almost full or almost empty valence shell tend to be very reactive. Strongly electronegative atoms (such as halogens) often have only one or two empty electron states in their valence shell, and frequently bond with other atoms or gain electrons to form anions. Weakly electronegative atoms (such as alkali metals) have relatively few valence electrons, which can easily be lost to strongly electronegative atoms. As a result, weakly electronegative atoms tend to distort their electron cloud and form cations. | 0 | Theoretical and Fundamental Chemistry |
Hydraulic systems use high fluid pressure, such as the hydraulic actuators for bulldozers and backhoes. Their hydraulic fittings are designed and rated for much greater pressure than that experienced in general piping systems, and they are generally not compatible with those used in plumbing. Hydraulic fittings are designed and constructed to resist high-pressure leakage and sudden failure. | 1 | Applied and Interdisciplinary Chemistry |
DCCC has been employed to separate a wide variety of phytochemicals from their crude extracts. The long list of natural product separations includes: saponins, alkaloids, senna glycosides, monosaccarides, triterpene glycosides, flavone glycosides, xanthones, iridoid glycosides, vitamin B, lignans, imbricatolic acid, gallic acid, carotenoids, and triterpenoids.
DCCC instruments have been commercially manufactured and distributed by Büchi and Tokyo Rikakikai (Eyela). | 0 | Theoretical and Fundamental Chemistry |
Imipenem (trade name Primaxin among others) is a synthetic β-lactam antibiotic belonging to the carbapenems chemical class. developed by Merck scientists Burton Christensen, William Leanza, and Kenneth Wildonger in the mid-1970s. Carbapenems are highly resistant to the β-lactamase enzymes produced by many multiple drug-resistant Gram-negative bacteria, thus playing a key role in the treatment of infections not readily treated with other antibiotics. It is usually administered through intravenous injection.
Imipenem was patented in 1975 and approved for medical use in 1985. It was developed via a lengthy trial-and-error search for a more stable version of the natural product thienamycin, which is produced by the bacterium Streptomyces cattleya. Thienamycin has antibacterial activity, but is unstable in aqueous solution, thus it is practically of no medicinal use. Imipenem has a broad spectrum of activity against aerobic and anaerobic, Gram-positive and Gram-negative bacteria. It is particularly important for its activity against Pseudomonas aeruginosa and Enterococcus species. However, it is not active against MRSA. | 0 | Theoretical and Fundamental Chemistry |
Rivers whose discharge is liable to become quite small at their low stage, or which have a somewhat large fall, as is usual in the upper part of rivers, cannot be given an adequate depth for navigation purely by works which regulate the flow; their ordinary summer level has to be raised by impounding the flow with weirs at intervals across the channel, while a lock has to be provided alongside the weir, or in a side channel, to provide for the passage of vessels. A river is thereby converted into a succession of fairly level reaches rising in steps up-stream, providing still-water navigation comparable to a canal; but it differs from a canal in the introduction of weirs for keeping up the water-level, in the provision for the regular discharge of the river at the weirs, and in the two sills of the locks being laid at the same level instead of the upper sill being raised above the lower one to the extent of the rise at the lock, as usual on canals.
Canalization secures a definite available depth for navigation; and the discharge of the river generally is amply sufficient for maintaining the impounded water level, as well as providing the necessary water for locking. Navigation, however, is liable to be stopped during the descent of high floods, which in many cases rise above the locks; and it is necessarily arrested in cold climates on all rivers by long, severe frosts, and especially by ice. Many small rivers, like the Thames above its tidal limit, have been rendered navigable by canalization, and several fairly large rivers have thereby provided a good depth for vessels for considerable distances inland. Thus the canalized Seine has secured a navigable depth of 10 feet (3.2 metres) from its tidal limit up to Paris, a distance of 135 miles, and a depth of 6 feet (2.06 metres) up to Montereau, 62 miles higher up. | 1 | Applied and Interdisciplinary Chemistry |
In materials science and biology, capillary condensation is the "process by which multilayer adsorption from the vapor [phase] into a porous medium proceeds to the point at which pore spaces become filled with condensed liquid from the vapor [phase]." The unique aspect of capillary condensation is that vapor condensation occurs below the saturation vapor pressure, , of the pure liquid. This result is due to an increased number of van der Waals interactions between vapor phase molecules inside the confined space of a capillary. Once condensation has occurred, a meniscus immediately forms at the liquid-vapor interface which allows for equilibrium below the saturation vapor pressure. Meniscus formation is dependent on the surface tension of the liquid and the shape of the capillary, as shown by the Young-Laplace equation. As with any liquid-vapor interface involving a meniscus, the Kelvin equation provides a relation for the difference between the equilibrium vapor pressure and the saturation vapor pressure. A capillary does not necessarily have to be a tubular, closed shape, but can be any confined space with respect to its surroundings.
Capillary condensation is an important factor in both naturally-occurring and synthetic porous structures. In these structures, scientists use the concept of capillary condensation to determine pore size distribution and surface area through adsorption isotherms. Synthetic applications such as sintering of materials are also highly dependent on bridging effects resulting from capillary condensation. In contrast to the advantages of capillary condensation, it can also cause many problems in materials science applications such as atomic-force microscopy and microelectromechanical systems. | 1 | Applied and Interdisciplinary Chemistry |
Small non-coding RNA (sncRNA) are a type of RNA. which is usually defined as transcripts which are lesser than 200 base-pairs in length and not translated into proteins. This limitation distinguishes sncRNA from lncRNA. This class includes but is not limited to microRNAs (miRNAs), small interfering RNAs (siRNAs), Piwi-interacting RNAs (piRNAs), small nucleolar RNAs (snoRNAs), and other short RNAs. | 1 | Applied and Interdisciplinary Chemistry |
RNA velocity is based on bridging measurements to a underlying mechanism, mRNA splicing, with two modes indicating the current and future state. It is a method used to predict the future gene expression of a cell based on the measurement of both spliced and unspliced transcripts of mRNA.
RNA velocity could be used to infer the direction of gene expression changes in single-cell RNA sequencing (scRNA-seq) data. It provides insights into the future state of individual cells by using the abundance of unspliced to spliced RNA transcripts. This ratio can indicate the transcriptional dynamics and potential fate of a cell, such as whether it is transitioning from one cell type to another or undergoing differentiation. | 1 | Applied and Interdisciplinary Chemistry |
MOSE consists of rows of mobile gates on the seabed at the three inlets that can be raised to temporarily seal off the lagoon from the sea during high tide. There are 78 gates grouped into four barrier rows. At the Lido inlet, the widest, there are two barrier rows of 21 and 20 gates, respectively, linked by an artificial island (the island connecting the two rows of gates at the centre of the Lido inlet also accommodates the technical buildings housing the system operating plant). In addition, there is one row of 19 gates at the Malamocco inlet and one row of 18 gates at the Chioggia inlet.
The gates consist of metal box-type structures wide for all rows, with a length varying between and from thick. The gates are connected to the concrete housing structures with hinges, the technological heart of the system, which allow the gates to move while attached to the housing structures on the seafloor.
Under normal tidal conditions, the gates are full of water and rest in their housing structures. When a high tide is forecast, compressed air is introduced into the gates to empty them of water, causing them to rotate around the axis of the hinges and rise up until they emerge above the water to stop the tide from entering the lagoon. When the tide recedes, the gates are filled with water again and lowered into their housing.
The inlets are closed for an average of between four and five hours, including the time taken for the gates to be raised (about 30 minutes) and lowered (about 15 minutes).
To guarantee navigation and avoid interruption of activities in the Port of Venice, when the mobile barriers are in operation, a main lock is constructed at the Malamocco inlet to allow the transit of large ships; while at the Lido and Chioggia inlets, there are smaller locks to allow emergency vessels, fishing boats and pleasure craft to shelter and transit.
Operating procedure dictates that the gates will be raised for tides of more than high. The authorities have established this as the optimum height with respect to current sea levels, but the gates can be operated for any level of tide. The MOSE system is flexible: depending on the winds, atmospheric pressure and level of tide, it can oppose the high water in different ways – with simultaneous closure of all three inlets in the case of exceptional tides, by closing just one inlet at a time, or by partially closing each inletgiven that the gates are independentfor medium-high tides. | 1 | Applied and Interdisciplinary Chemistry |
Compared with single-phase heat transfer, heat transfer with a phase change is an effective way of heat transfer. It generally has high value of heat transfer coefficient due to the large value of latent heat of phase change followed by induced mixing of the flow. Boiling and condensation heat transfers are concerned with wide range of phenomena. | 0 | Theoretical and Fundamental Chemistry |
In waste water treatment, the most commonly used adsorbent is granular activated carbon (GAC), often used as to treat both liquid and gas phase volatile organic compounds and organic pollutants. Activated carbon beds vary in lifetime depending on the concentration of the pollutant(s) being removed, their associated adsorption isotherms, inlet flow rates and required discharge consents. Life- times of these beds can range between hours and months. Activated carbon is often landfilled at the end of its useful life but sometimes it is possible to regenerate it restoring its adsorptive capacity allowing it to be re-used. Thermal regeneration is the most prolific regeneration technique but has drawbacks in terms of high energy and commercial costs and a significant carbon footprint. These drawbacks have encouraged research into alternative regeneration techniques such as electrochemical regeneration. | 0 | Theoretical and Fundamental Chemistry |
Depending on the organism, an archaeon may use a bacteria-like HU system or a eukaryote-like nucleosome system for packaging. | 1 | Applied and Interdisciplinary Chemistry |
Chemokine receptors associate with G-proteins to transmit cell signals following ligand binding. Activation of G proteins, by chemokine receptors, causes the subsequent activation of an enzyme known as phospholipase C (PLC). PLC cleaves a molecule called phosphatidylinositol (4,5)-bisphosphate (PIP2) into two second messenger molecules known as Inositol triphosphate (IP3) and diacylglycerol (DAG) that trigger intracellular signaling events; DAG activates another enzyme called protein kinase C (PKC), and IP3 triggers the release of calcium from intracellular stores. These events promote many signaling cascades (such as the MAP kinase pathway) that generate responses like chemotaxis, degranulation, release of superoxide anions and changes in the avidity of cell adhesion molecules called integrins within the cell harbouring the chemokine receptor. | 1 | Applied and Interdisciplinary Chemistry |
Shape-memory alloys are applied in medicine, for example, as fixation devices for osteotomies in orthopaedic surgery, as the actuator in surgical tools; active steerable surgical needles for minimally invasive percutaneous cancer interventions in the surgical procedures such as biopsy and brachytherapy, in dental braces to exert constant tooth-moving forces on the teeth, in Capsule Endoscopy they can be used as a trigger for biopsy action.
The late 1980s saw the commercial introduction of Nitinol as an enabling technology in a number of minimally invasive endovascular medical applications. While more costly than stainless steel, the self expanding properties of Nitinol alloys manufactured to BTR (Body Temperature Response), have provided an attractive alternative to balloon expandable devices in stent grafts where it gives the ability to adapt to the shape of certain blood vessels when exposed to body temperature. On average, of all peripheral vascular stents currently available on the worldwide market are manufactured with Nitinol. | 1 | Applied and Interdisciplinary Chemistry |
A sensor-based sorting equipment supplier with large installed base in the industries mining, recycling and food. Tomras sensor-based sorting equipment and services for the precious metals and base metals segment are marketed through a cooperation agreement with Outotec from Finland, which brings the extensive comminution, processing and application experience of Outotec together with Tomras sensor-based ore sorting technology and application expertise. | 0 | Theoretical and Fundamental Chemistry |
Though the specific mechanisms by which paramutation acts vary from organism to organism, all well-documented cases point towards epigenetic modification and RNA-silencing as the underlying mechanism for paramutation.
In the case of the r1 locus in maize, DNA methylation of a region of tandem repeats near the coding region of the gene is characteristic of the paramutagenic B’ allele, and when the paramutable B-I allele becomes paramutagenic, it too takes on the same DNA methylation pattern. In order for this methylation to be successfully transferred, a number of genes coding for RNA-dependent RNA polymerases and other components of RNA-silencing pathways are required, suggesting that paramutation is mediated via endogenous RNA-silencing pathways. The transcription of short interfering RNAs from the tandem repeat regions corroborates this. In animal systems such as Drosophila, piRNAs have also been implicated in mediating paramutation. In addition to the characteristic DNA methylation state changes, changes in histone modification patterns in the methylated DNA regions, and/or the requirement of histone modifying proteins to mediate paramutation have also been noted in multiple systems. It has been suggested that these histone modifications play a role in maintaining the paramutated state. The previously mentioned tandem repeat region in the r1 locus is also typical of other loci showing paramutation or paramutation-like phenomena.
However, it has been noted that it is not possible to explain all occurrences and features of paramutation with what is known about RNAi-mediated transcriptional silencing, suggesting that other pathways and/or mechanisms are also at play. | 1 | Applied and Interdisciplinary Chemistry |
In fMRS, depending on the focus of the study, either single-voxel or multi-voxel spectroscopic technique can be used.
In single-voxel fMRS the selection of the volume of interest (VOI) is often done by running a functional magnetic resonance imaging (fMRI) study prior to fMRS to localize the brain region activated by the task. Single-voxel spectroscopy requires shorter acquisition times; therefore it is more suitable for fMRS studies where high temporal resolution is needed and where the volume of interest is known.
Multi-voxel spectroscopy provides information about group of voxels and data can be presented in 2D or 3D images, but it requires longer acquisition times and therefore temporal resolution is decreased. Multi-voxel spectroscopy usually is performed when the specific volume of interest is not known or it is important to study metabolite dynamics in a larger brain region. | 0 | Theoretical and Fundamental Chemistry |
In homogeneous photocatalysis, the reactants and the photocatalysts exist in the same phase. The process by which the atmosphere self-cleans and removes large organic compounds is a gas phase homogenous photocatalysis reaction. The ozone process is often referenced when developing many photocatalysts:
Most homogeneous photocatalytic reactions are aqueous phase, with a transition-metal complex photocatalyst. The wide use of transition-metal complexes as photocatalysts is in large part due to the large band gap and high stability of the species. Homogeneous photocatalysts are common in the production of clean hydrogen fuel production, with the notable use of cobalt and iron complexes.
Iron complex hydroxy-radical formation using the ozone process is common in the production of hydrogen fuel (similar to Fenton's reagent process done in low pH conditions without photoexcitation):
Complex-based photocatalysts are semiconductors, and operate under the same electronic properties as heterogeneous catalysts. | 0 | Theoretical and Fundamental Chemistry |
An Ubbelohde type viscometer or suspended-level viscometer is a measuring instrument which uses a capillary based method of measuring viscosity. It is recommended for higher viscosity cellulosic polymer solutions. The advantage of this instrument is that the values obtained are independent of the total volume. The device was developed by the German chemist Leo Ubbelohde (1877-1964).
ASTM and other test methods are: ISO 3104, ISO 3105, ASTM D445, ASTM D446, ASTM D4020, IP 71, BS 188.
The Ubbelohde viscometer is closely related to the Ostwald viscometer. Both are u-shaped pieces of glassware with a reservoir on one side and a measuring bulb with a capillary on the other. A liquid is introduced into the reservoir then sucked through the capillary and measuring bulb. The liquid is allowed to travel back through the measuring bulb and the time it takes for the liquid to pass through two calibrated marks is a measure for viscosity. The Ubbelohde device has a third arm extending from the end of the capillary and open to the atmosphere. In this way the pressure head only depends on a fixed height and no longer on the total volume of liquid. | 0 | Theoretical and Fundamental Chemistry |
When κa is between large values where simple analytical models are available, and low values where numerical calculations are valid, Henrys equation can be used when the zeta potential is low. For a nonconducting sphere, Henrys equation is , where f is the Henry function, one of a collection of functions which vary smoothly from 1.0 to 1.5 as κa approaches infinity. | 0 | Theoretical and Fundamental Chemistry |
An example of a mineral containing hydroxyl groups is garnet. Garnet is an anhydrous mineral commonly analyzed within geological subdisciplines because of its general stability. One study analyzed the presence of garnets within the upper mantle through infrared spectroscopy and showed absorption at approximately 3500 cm, which is consistent with the presence of hydroxyl groups. These garnets have been shown to vary in composition dependent on its geographic origin. One particular study in Southern Africa determined concentrations ranging from 1 ppm - 135 ppm. However, this is significantly lower than the hydroxyl content in regions such as the Colorado Plateau. It was also demonstrated that there is an inverse correlation regarding the concentration of OH and Mg + Fe. | 0 | Theoretical and Fundamental Chemistry |
A protecting group or protective group is introduced into a molecule by chemical modification of a functional group to obtain chemoselectivity in a subsequent chemical reaction, facilitating multistep organic synthesis.
*Boc for the t-butoxycarbonyl group
*Cbz or Z for the carboxybenzyl group
*Fmoc for the fluorenylmethoxycarbonyl group
*Alloc for the allyloxycarbonyl group
*Troc for the trichloroethoxycarbonyl group
*TMS, TBDMS, TES, TBDPS, TIPS, ... for various silyl ether groups
*PMB for the 4-methoxybenzyl group
*MOM for the methoxymethyl group
*THP for the 2-tetrahydropyranyl group | 0 | Theoretical and Fundamental Chemistry |
After finishing school, Hammond began working at Howe & Leeds Wholesale West India Goods Store on Boston's Long Wharf. The same year, he became a clerk with J. W. Blodgett & Co.
Hammond attended the Massachusetts Institute of Technology as a special student on the chemistry of paper manufacturing.
After moving to Maine part-time, in 1853 he accepted a position at his uncle Samuel Dennis Warrens S. D. Warren Paper Mill in Cumberland Mills. By 1857, he was superintendent, a role in which remained for five years. His next position was as the mills agent.
In 1874, Hammond and Warren bought the rights to Yarmouth Paper Company, in Yarmouth, Maine, at the towns Third Falls. They renamed it Forest Paper Company. Beginning with a single wooden building, the facility expanded to ten buildings covering as many acres, including a span over the Royal River to Factory Island. Two bridges to it were also constructed. In 1909, the year following Hammonds death, it was the largest such mill in the world, employing 275 people. Hammond also worked at the S. D. Warren mill until 1876, before transferring full-time to Yarmouth as the manager of the new business. The mill became known as a pioneer in the processing of soda pulp.
Hammond retired from active business on January 1, 1906. | 1 | Applied and Interdisciplinary Chemistry |
Within a long region of genomic sequence, genes are often characterised by having a higher GC-content in contrast to the background GC-content for the entire genome. There is evidence that the length of the coding region of a gene is directly proportional to higher G+C content. This has been pointed to the fact that the stop codon has a bias towards A and T nucleotides, and, thus, the shorter the sequence the higher the AT bias.
Comparison of more than 1,000 orthologous genes in mammals showed marked within-genome variations of the third-codon position GC content, with a range from less than 30% to more than 80%. | 1 | Applied and Interdisciplinary Chemistry |
TNO (gastro-) Intestinal Models (“TIM”) are model systems mimicking the digestive tract. The models are dynamic computer controlled multi-compartmental systems with adjustable parameters for the physiological conditions of the stomach and intestine. Temperature, peristalsis, bile secretion, secretion of saliva, stomach and pancreas enzymes are all fully adjustable.
The TIM systems are being used to study the behavior of oral products during transit through the stomach, the small intestine and large intestine. Commonly performed studies concern the digestibility of food and food components, the bioaccessibility for absorption of pharmaceutical compounds, proteins, fat, minerals and (water- and fat-soluble) vitamins.
There are different models for the stomach and small intestine (TIM-1 and Tiny-TIM) and a model simulating the physiological conditions of the colon (TIM-2).
The TIM-1 system consists of a stomach compartment and 3 compartments for the small intestine, the duodenum, jejunum and ileum. The Tiny-TIM system consists of a stomach compartment and one single compartment for the small intestine. Samples can be harvested for analysis from these models from any compartment at any time.
TIM-2 simulates the colon, containing the microbiota as found in human colon. This model serves as a tool to study fermentation of non-digestible food components (fibers and prebiotics) and the release of drugs specifically targeted for the colon. | 1 | Applied and Interdisciplinary Chemistry |
A sieve analysis (or gradation test) is a practice or procedure used in civil engineering and chemical engineering to assess the particle size distribution (also called gradation) of a granular material by allowing the material to pass through a series of sieves of progressively smaller mesh size and weighing the amount of material that is stopped by each sieve as a fraction of the whole mass.
The size distribution is often of critical importance to the way the material performs in use. A sieve analysis can be performed on any type of non-organic or organic granular materials including sand, crushed rock, clay, granite, feldspar, coal, soil, a wide range of manufactured powder, grain and seeds, down to a minimum size depending on the exact method. Being such a simple technique of particle sizing, it is probably the most common. | 1 | Applied and Interdisciplinary Chemistry |
The spinthariscope was invented by William Crookes in 1903. While observing the apparently uniform fluorescence on a zinc sulfide screen created by the radioactive emissions (mostly alpha radiation) of a sample of radium bromide, he spilled some of the sample, and, owing to its extreme rarity and cost, he was eager to find and recover it. Upon inspecting the zinc sulfide screen under a microscope, he noticed separate flashes of light created by individual alpha particle collisions with the screen. Crookes took his discovery a step further and invented a device specifically intended to view these scintillations. It consisted of a small screen coated with zinc sulfide affixed to the end of a tube, with a tiny amount of radium salt suspended a short distance from the screen and a lens on the other end of the tube for viewing the screen. Crookes named his device from () "spark".
Crookes debuted the spinthariscope at a meeting of the Royal Society, London on 15 May 1903. | 0 | Theoretical and Fundamental Chemistry |
* Fulbright Scholar in Marine Resources, Portugal (2020)
*A.G. Huntsman Award for Excellence in Marine Science (2019)
* Fellow, American Geophysical Union (2018)
* Fellow, Association for the Sciences of Limnology and Oceanography (ASLO, 2016)
* Dansgaard Award, AGU mid-career Paleoceanography Award (2015)
*Fellow, Geochemical Society (2014)
* American Geophysical Union's Rachel Carson Lecture (2013)
*Excellence Chair of the Prof. Dr. Werner Petersen Foundation from GEOMAR
* American Geophysical Union's Ocean Sciences Early Career Award (2004) | 0 | Theoretical and Fundamental Chemistry |
Dna2 endonuclease does not have a specific structure and their properties are not well characterized, but could be referred as single-stranded DNA with free ends (ssDNA). Dna2 endonuclease is essential to cleave long DNA flaps that leave FEN1 during the Okazaki Process. Dna2 endonuclease is responsible for the removal of the initiator RNA segment on Okazaki Fragments. Also, Dna2 endonuclease has a pivotal role in the intermediates created during diverse DNA metabolisms and is functional in telomere maintenance.
Dna2 endonuclease becomes active when a terminal RNA segment attaches at the 5’ end, because it translocates in the 5’ to 3’ direction. In the presence of a single stranded DNA-binding protein RPA, the DNA 5 flaps become too long, and the nicks no longer fit as substrate for FEN1. This prevents the FEN1 from removing the 5′-flaps. Thus, Dna2s role is to reduce the 3′ end of these fragments, making it possible for FEN1 to cut the flaps, and the Okazaki fragment maturation more efficient. During the Okazaki Process, Dna2 helicase and endonuclease are inseparable. Dna2 Endonuclease does not depend on the 5’-tailed fork structure of its activity. Unproductive binding has been known to create blocks to FEN1 cleavage and tracking. It is known that ATP reduces activity, but promotes the release of the 3’-end label. Studies have suggested that a new model of Dna2 Endonuclease and FEN1 are partially responsible in Okazaki fragment maturation. | 1 | Applied and Interdisciplinary Chemistry |
Cyclopropyl cyanide, when heated to 660-760K and under pressure of 2-89torr, becomes cis and trans crotonitrile and allyl cyanide molecules, with some presence of methacrylonitrile. This is an isomerization reaction that is homogeneous with rate of first order. The reaction result is due to the biradical mechanism, which involves the formation of carbon radicals as the three carbon ring opens up. The radicals then react to yield carbon=carbon double bonds. | 0 | Theoretical and Fundamental Chemistry |
Alexander Nikolayevich Nesmeyanov (; – 17 January 1980) was a Soviet chemist and academician (1943) specializing in organometallic chemistry. | 0 | Theoretical and Fundamental Chemistry |
The 16th century marked the beginning of scientific understanding of electricity and magnetism that culminated with the production of electric power and the industrial revolution in the late 19th century.
In the 1550s, English scientist William Gilbert spent 17 years experimenting with magnetism and, to a lesser extent, electricity. For his work on magnets, Gilbert became known as "The Father of Magnetism." His book De Magnete quickly became the standard work throughout Europe on electrical and magnetic phenomena, and made a clear distinction between magnetism and what was then called the "amber effect" (static electricity).
In 1663, German physicist Otto von Guericke created the first electrostatic generator, which produced static electricity by applying friction. The generator was made of a large sulfur ball inside a glass globe, mounted on a shaft. The ball was rotated by means of a crank and a static electric spark was produced when a pad was rubbed against the ball as it rotated. The globe could be removed and used as an electrical source for experiments with electricity. Von Guericke used his generator to show that like charges repelled each other. | 0 | Theoretical and Fundamental Chemistry |
Mathematical models act as an important tool in various bio-reactor applications including wastewater treatment. These models are useful for planning efficient process control strategies and predicting the future plant performance. Moreover, these models are beneficial in education and research areas.
Bioreactors are generally used in those industries which are concerned with food, beverages and pharmaceuticals. The emergence of biochemical engineering is of recent origin. Processing of biological materials using biological agents such as cells, enzymes or antibodies are the major pillars of biochemical engineering. Applications of biochemical engineering cover major fields of civilization such as agriculture, food and healthcare, resource recovery and fine chemicals.
Until now, the industries associated with biotechnology have lagged behind other industries in implementing control over the process and optimization strategies. A main drawback in biotechnological process control is the problem of measuring key physical and biochemical parameters. | 1 | Applied and Interdisciplinary Chemistry |
Changes in ocean chemistry can have extensive direct and indirect effects on organisms and their habitats. One of the most important repercussions of increasing ocean acidity relates to the production of shells out of calcium carbonate (). This process is called calcification and is important to the biology and survival of a wide range of marine organisms. Calcification involves the precipitation of dissolved ions into solid structures, structures for many marine organisms, such as coccolithophores, foraminifera, crustaceans, mollusks, etc. After they are formed, these structures are vulnerable to dissolution unless the surrounding seawater contains saturating concentrations of carbonate ions ().
Very little of the extra carbon dioxide that is added into the ocean remains as dissolved carbon dioxide. The majority dissociates into additional bicarbonate and free hydrogen ions. The increase in hydrogen is larger than the increase in bicarbonate, creating an imbalance in the reaction:
To maintain chemical equilibrium, some of the carbonate ions already in the ocean combine with some of the hydrogen ions to make further bicarbonate. Thus the ocean's concentration of carbonate ions is reduced, removing an essential building block for marine organisms to build shells, or calcify:
The increase in concentrations of dissolved carbon dioxide and bicarbonate, and reduction in carbonate, are shown in the Bjerrum plot. | 0 | Theoretical and Fundamental Chemistry |
Meropenem rapidly reduces serum concentrations of valproic acid. As a result, people who use valproic acid for epilepsy are at increased risk of seizures during treatment with meropenem. In situations where the use of meropenem cannot be avoided, prescription of an additional anticonvulsant should be considered. | 0 | Theoretical and Fundamental Chemistry |
*. For conservative case, this reduces to .
*. For conservative case, this reduces to .
*If the characteristic function is , where are two constants(have to satisfy ) and if is the nth moment of the H function, then we have
and | 0 | Theoretical and Fundamental Chemistry |
The six criteria air pollutants were the first set of pollutants recognized by the United States Environmental Protection Agency as needing standards on a national level. The Clean Air Act requires the EPA to set US National Ambient Air Quality Standards (NAAQS) for the six CAPs. The NAAQS are health based and the EPA sets two types of standards: primary and secondary. The primary standards are designed to protect the health of sensitive populations such as asthmatics, children, and the elderly. The secondary standards are concerned with protecting the environment. They are designed to address visibility, damage to crops, vegetation, buildings, and animals.
The EPA established the NAAQS according to Sections 108 and 109 of the U.S. Clean Air Act, which was last amended in 1990. These sections require the EPA "(1) to list widespread air pollutants that reasonably may be expected to endanger public health or welfare; (2) to issue air quality criteria for them that assess the latest available scientific information on nature and effects of ambient exposure to them; (3) to set primary NAAQS to protect human health with adequate margin of safety and to set secondary NAAQS to protect against welfare effects (e.g., effects on vegetation, ecosystems, visibility, climate, manmade materials, etc); and (5) to periodically review and revise, as appropriate, the criteria and NAAQS for a given listed pollutant or class of pollutants." | 1 | Applied and Interdisciplinary Chemistry |
Demethylation (the transfer of the methyl group to another compound) is a common process, and reagents that undergo this reaction are called methylating agents. Common methylating agents are dimethyl sulfate, methyl iodide, and methyl triflate. Methanogenesis, the source of natural gas, arises via a demethylation reaction. Together with ubiquitin and phosphorylation, methylation is a major biochemical process for modifying protein function. The field of epigenetics focuses on the influence of methylation on gene expression. | 0 | Theoretical and Fundamental Chemistry |
Optical depth measures the attenuation of the transmitted radiant power in a material. Attenuation can be caused by absorption, but also reflection, scattering, and other physical processes. Optical depth of a material is approximately equal to its attenuation when both the absorbance is much less than 1 and the emittance of that material (not to be confused with radiant exitance or emissivity) is much less than the optical depth:
where
*Φ is the radiant power transmitted by that material;
*Φ is the radiant power attenuated by that material;
*Φ is the radiant power received by that material;
*Φ is the radiant power emitted by that material;
*T = Φ/Φ is the transmittance of that material;
*ATT = Φ/Φ is the attenuation of that material;
*E = Φ/Φ is the emittance of that material,
and according to the Beer–Lambert law,
so: | 0 | Theoretical and Fundamental Chemistry |
Sea salt is mentioned in the Vinaya Pitaka, a Buddhist scripture compiled in the mid-5th century BC. The principle of production is evaporation of the water from the sea brine. In warm and dry climates this may be accomplished entirely by using solar energy, but in other climates fuel sources have been used. Modern sea salt production is almost entirely found in Mediterranean and other warm, dry climates.
Such places are today called salt works, instead of the older English word saltern. An ancient or medieval saltern was established where there was:
# Access to a market for the salt
# A gently shelving coast, protected from exposure to the open sea
# An inexpensive and easily worked fuel supply, or preferably the sun
# Another trade, such as pastoral farming or tanning—which benefited from proximity to the saltern (by producing leather, salted meat, etc.) and provided the saltern with a local market
In this way, salt marsh, pasture (salting), and salt works (saltern) enhanced each other economically. This was the pattern during the Roman and medieval periods around The Wash, in eastern England. There, the tide brought the brine, the extensive saltings provided the pasture, the fens and moors provided the peat fuel, and the sun sometimes shone.
The dilute brine of the sea was largely evaporated by the sun. In Roman areas, this was done using ceramic containers known as briquetage. Workers scraped up the concentrated salt and mud slurry and washed it with clean sea water to settle impurities out of the now concentrated brine. They poured the brine into shallow pans (lightly baked from local marine clay) and set them on fist-sized clay pillars over a peat fire for final evaporation. Then they scraped out the dried salt and sold it.
In traditional salt production in the Visayas Islands of the Philippines, salt are made from coconut husks, driftwood, or other plant matter soaked in seawater for at least several months. These are burned into ash then seawater is run through the ashes on a filter. The resulting brine is then evaporated in containers. Coconut milk is sometimes added to the brine before evaporation. The practice is endangered due to competition with cheap industrially-produced commercial salt. Only two traditions survive to the present day: asín tibuok and túltul (or dúkdok).
In the colonial New World, slaves were brought from Africa to rake salt on various islands in the West Indies, Bahamas and particularly Turks and Caicos Islands.
Today, salt labelled "sea salt" in the US might not have actually come from the sea, as long as it meets the FDA's purity requirements. All mined salts were originally sea salts since they originated from a marine source at some point in the distant past, usually from an evaporating shallow sea. | 0 | Theoretical and Fundamental Chemistry |
Tools and weapons, chisels and axe-heads, spearheads or dagger-blades, are the only surviving artifacts of the Copper Age, and do not show artistic treatment. But some Early Minoan pottery forms are plainly copied from metal prototypes, cups and jugs of simple construction and rather elaborate design. The cups are conical and sometimes a stem-foot; there are oval jars with long tubular spouts, and beaked jugs with round shoulders set on conical bodies. Heads of rivets which tie the metal parts together are often reproduced as a decorative element in clay. The spouted jars and pierced type of axe-head indicate that metallurgical connections of Early Minoan Crete were partly Mesopotamian. | 1 | Applied and Interdisciplinary Chemistry |
Theodor W. Hänsch and John L. Hall shared half of the 2005 Nobel Prize in Physics for contributions to the development of laser-based precision spectroscopy, including the optical frequency-comb technique. The other half of the prize was awarded to Roy Glauber.
Also in 2005, the femtosecond comb technique was extended to the extreme ultraviolet range, enabling frequency metrology in that region of the spectrum. | 0 | Theoretical and Fundamental Chemistry |
The ability of pioneer factors to respond to extracellular signals to differentiate cell type has been studied as a potential component of hormone-dependent cancers. Hormones such as estrogen and IGFI are shown to increase pioneer factor concentration leading to a change in transcription. Known pioneer factors such as FoxA1, PBX1, TLE, AP2, GATA factors 2/3/4, and PU.1 have been associated with hormone-dependent cancer . FoxA1 is necessary for estrogen and androgen mediated hepatocarcinogenesis and is a defining gene for ER luminal breast cancer, as is another pioneer factor GATA3. FOXA1 particularly is expressed in 90% of breast cancer metastases and 89% of metastic prostate cancers. In the breast cancer cell line, MCF-7, it was found that FoxA1 was bound to 50% of estrogen receptor binding sites independent of estrogen presence. High expression of pioneer factors is associated with poor prognosis with the exception of breast cancer where FoxA1 is associated with a stronger outcome.
<br>
The correlation between pioneer factors and cancer has led to prospective therapeutic targeting. In knockdown studies in the MCF-7 breast cancer cell line it was found that decreasing pioneer factors FoxA1 and AP2 decreased ER signalling. Other fork head proteins have been associated with cancer, including FoxO3 and FoxM that repress the cell survival pathways Ras and PPI3K/AKT/IKK. Drugs such as Paclitaxel, Imatinib, and doxorubicin which activate FoxO3a or its targets are being used. Modification to modulate related factors with pioneer activity is a topic of interest in the early stages as knocking down pioneer factors may have toxic effects through alteration of the lineage pathways of healthy cells. | 1 | Applied and Interdisciplinary Chemistry |
Phosphates are medicinal salts of phosphorus. Some phosphates, which help cure many urinary tract infections, are used to make urine more acidic. To avoid the development of calcium stones in the urinary tract, some phosphates are used. For patients who are unable to get enough phosphorus in their daily diet, phosphates are used as dietary supplements, usually because of certain disorders or diseases. Injectable phosphates can only be handled by qualified health care providers. | 0 | Theoretical and Fundamental Chemistry |
PBr is prepared by treating red phosphorus with bromine. An excess of phosphorus is used in order to prevent formation of PBr:
:P + 6 Br → 4 PBr
Because the reaction is highly exothermic, it is often conducted in the presence of a diluent such as PBr. Phosphorus tribromide is also generated in situ from red phosphorus and bromine. | 0 | Theoretical and Fundamental Chemistry |
In 1997, several Georgian soldiers suffered radiation poisoning and burns. They were eventually traced back to training sources left abandoned, forgotten, and unlabeled after the dissolution of the Soviet Union. One was a caesium-137 pellet in a pocket of a shared jacket that released about 130,000 times the level of background radiation at 1 meter distance. | 0 | Theoretical and Fundamental Chemistry |
*Reiner Salzer (Chair), TU Dresden, Dresden, Germany
*Martino Di Serio (Vice-Chair), University of Naples Federico II, Naples, Italy
*Ray Wallace (Secretary), Nottingham Trent University, Nottingham, UK
*a number of members | 1 | Applied and Interdisciplinary Chemistry |
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