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Caution should be exercised in people who have narcolepsy in comorbidity with postural orthostatic tachycardia syndrome (POTS). Modafinil, like other centrally acting stimulants prescribed for people with narcolepsy, increases POTS-related autonomic dysfunction and results in tachycardia/arrhythmia side effects in people with cardiovascular risk factors. Sodium oxybate, a metabolite of GABA, is a CNS depressant which makes it an alternative drug for stimulant-intolerant people with POTS. | 0 | Theoretical and Fundamental Chemistry |
Synthesis: MOBs under reducing conditions using sodium hydroxide (NaOH), can be self-assembled at body temperature (37 degrees Celsius). In the case of copper CuHARS, MOBs can be produced by transforming copper nanoparticles to provide the copper source, or by utilizing copper(II) sulfate. | 0 | Theoretical and Fundamental Chemistry |
Since Ca is a common second messenger, GCaMP has been used to monitor the activation of signaling pathways. For instance, Bonder and McCarthy (2014) used GCaMP to show that astrocytic G-protein coupled receptor (GPCR) signaling and subsequent Ca release was not responsible for neurovascular coupling, the process by which changes in neuronal activity lead to changes in local blood flow. Similarly, Greer and Bear et al. (2016) used GCaMP to characterize the dynamics of Ca influx in necklace olfactory neuron signaling, which uses transmembrane MS4A proteins as chemoreceptors. | 1 | Applied and Interdisciplinary Chemistry |
The Biuret reagent is made of sodium hydroxide (NaOH) and hydrated copper(II) sulfate, together with potassium sodium tartrate, the latter of which is added to chelate and thus stabilize the cupric ions. The reaction of the cupric ions with the nitrogen atoms involved in peptide bonds leads to the displacement of the peptide hydrogen atoms under the alkaline conditions. A tri- or tetra-dentate chelation with the peptide nitrogen produces the characteristic color. This is found with dipeptides.
The reagent is commonly used in the biuret protein assay, a colorimetric test used to determine protein concentration by UV/VIS spectroscopy at wavelength 540 nm. | 0 | Theoretical and Fundamental Chemistry |
Pioneered by Stanley Fields and Ok-Kyu Song in 1989, the technique was originally designed to detect protein–protein interactions using the Gal4 transcriptional activator of the yeast Saccharomyces cerevisiae. The Gal4 protein activated transcription of a gene involved in galactose utilization, which formed the basis of selection. Since then, the same principle has been adapted to describe many alternative methods, including some that detect protein–DNA interactions or DNA-DNA interactions, as well as methods that use different host organisms such as Escherichia coli or mammalian cells instead of yeast. | 1 | Applied and Interdisciplinary Chemistry |
Melt inclusions are generally small - most are less than 80 micrometres across (a micrometre is one thousandth of a millimeter, or about 0.00004 inches). They may contain a number of different constituents, including glass (which represents melt that has been quenched by rapid cooling), small crystals and a separate vapour-rich bubble. They occur in the crystals that can be found in igneous rocks, such as for example quartz, feldspar, olivine, pyroxene, nepheline, magnetite, perovskite and apatite. Melt inclusions can be found in both volcanic and plutonic rocks. In addition, melt inclusions can contain immiscible (non-miscible) melt phases and their study is an exceptional way to find direct evidence for presence of two or more melts at entrapment. | 0 | Theoretical and Fundamental Chemistry |
Massive fish die-offs have been caused by HABs. In 2016, 23 million salmon which were being farmed in Chile died from a toxic algae bloom. To get rid of the dead fish, the ones fit for consumption were made into fishmeal and the rest were dumped 60 miles offshore to avoid risks to human health. The economic cost of that die-off is estimated to have been $800 million. Environmental expert Lester Brown has written that the farming of salmon and shrimp in offshore ponds concentrates waste, which contributes to eutrophication and the creation of dead zones.
Other countries have reported similar impacts, with cities such as Rio de Janeiro, Brazil seeing major fish die-offs from blooms becoming a common occurrence. In early 2015, Rio collected an estimated 50 tons of dead fish from the lagoon where water events in the 2016 Olympics were planned to take place.
The Monterey Bay has suffered from harmful algal blooms, most recently in 2015: "Periodic blooms of toxin-producing Pseudo-nitzschia diatoms have been documented for over 25 years in Monterey Bay and elsewhere along the U.S. west coast. During large blooms, the toxin accumulates in shellfish and small fish such as anchovies and sardines that feed on algae, forcing the closure of some fisheries and poisoning marine mammals and birds that feed on contaminated fish." Similar fish die-offs from toxic algae or lack of oxygen have been seen in Russia, Colombia, Vietnam, China, Canada, Turkey, Indonesia, and France. | 0 | Theoretical and Fundamental Chemistry |
During 2010, the United States Department of Energy established the Joint Center for Artificial Photosynthesis. The mission of JCAP is to find a cost-effective method to produce fuels using only sunlight, water, and carbon-dioxide as inputs. JCAP is managed by a team from the California Institute of Technology (Caltech), directed by Professor Nathan Lewis and brings together more than 120 scientists and engineers from Caltech and its main partner, Lawrence Berkeley National Laboratory. JCAP also draws on the expertise and capabilities of key partners from Stanford University, the University of California at Berkeley, UCSB, University of California, Irvine, and University of California at San Diego, and the Stanford Linear Accelerator. Additionally, JCAP serves as a central hub for other solar fuels research teams across the United States, including 20 DOE Energy Frontier Research Center. The program had a budget of $122M over five years, subject to Congressional appropriation | 0 | Theoretical and Fundamental Chemistry |
Chromatin Immunoprecipitation results in production of complex mixtures of relatively short DNA fragments, which is challenging to amplify with MDA without causing a bias in the fragment representation. A method to circumvent this problem was proposed, which is based on conversion of these mixtures to circular concatemers using ligation, followed by Φ29 DNA polymerase-mediated MDA. | 1 | Applied and Interdisciplinary Chemistry |
The initiating methionine (and, in prokaryotes, fMet) may be removed during translation of the nascent protein. For E. coli, fMet is efficiently removed if the second residue is small and uncharged, but not if the second residue is bulky and charged. In both prokaryotes and eukaryotes, the exposed N-terminal residue may determine the half-life of the protein according to the N-end rule. | 1 | Applied and Interdisciplinary Chemistry |
Once a suitable genomic fragment is chosen (Step 1), the exons and introns of the fragment can be inserted and amplified, along with the flanking constitutive exons and introns of the original gene, by PCR. The primers for PCR can be chosen so that they leave "sticky ends" at 3' sense and anti-sense strands (Step 2). These "sticky-ends" can be easily incorporated into a TOPO Vector by ligation into a commercially available source which has ligase already attached to it at the sight of incorporation (Step 3). The subsequent TOPO Vectors can be transfected into E.coli cells (Step 4). After incubation, total RNA can be extracted from the bacterial colonies and analyzed using RT-PCR to quantify ratios of exon inclusion/exclusion (step 5). The minigene can be transfected into different cell types with various splicing factors to test trans-acting elements (Step 6). The expressed genes or the proteins they encode can be analyzed to evaluate splicing components and their effects via a variety of methods including hybridization or size-exclusion chromatography. | 1 | Applied and Interdisciplinary Chemistry |
Several companies in the United States are now working to commercialize supercritical reactors to destroy hazardous wastes. Widespread commercial application of SCWO technology requires a reactor design capable of resisting fouling and corrosion under supercritical conditions.
In Japan a number of commercial SCWO applications exist, among them one unit for treatment of halogenated waste built by Organo. In Korea two commercial size units have been built by Hanwha.
In Europe, Chematur Engineering AB of Sweden commercialized the SCWO technology for treatment of spent chemical catalysts to recover the precious metal, the AquaCat process. The unit has been built for Johnson Matthey in the UK. It is the only commercial SCWO unit in Europe and with its capacity of 3000l/h it is the largest SCWO unit in the world. Chematur's Super Critical Fluids technology was acquired by SCFI Group (Cork, Ireland) who are actively commercializing the Aqua Critox SCWO process for treatment of sludge, e.g. de-inking sludge and sewage sludge. Many long duration trials on these applications have been made and thanks to the high destruction efficiency of 99.9%+ the solid residue after the SCWO process is well suited for recycling – in the case of de-inking sludge as paper filler and in the case of sewage sludge as phosphorus and coagulant. SCFI Group operate a 250l/h Aqua Critox demonstration plant in Cork, Ireland.
Turbosystems Engineering (California, USA) is actively commercializing their patented transpiring wall SCWO reactor ("TWR") with a focus on renewable energy applications.
374Water Inc. is a company offering commercial SCWO systems that convert organic wastes to clean water, energy and minerals. It is spun out after more than seven years of research and development funded by the Bill & Melinda Gates Foundation to Prof. Deshusses laboratory based at Duke University. The founders of 374Water, Prof. Marc Deshusses and Kobe Nagar, possess the waste processing reactor patent relevant to SCWO. 374Water is actively commercializing its AirSCWO systems for the treatment of biosolids and wastewater sludges, organic chemical wastes, and PFAS wastes including unspent Aqueous Film Forming Foams (AFFFs), rinsates or spent resins and adsorption media. The first commercial sale was announced in February 2022.
Aquarden Technologies (Skaevinge, Denmark) provides modular SCWO plants for the destruction of hazardous pollutants such as PFAS, pesticides, and other problematic hydrocarbons in industrial wastestreams. Aquarden is also providing remediation of hazardous energetic wastes and chemical warfare agents with SCWO, where a full-scale SCWO system has been operating for some years in France for the Defense Industry. | 0 | Theoretical and Fundamental Chemistry |
Satyam et al. from National University of Ireland, Galway (NUI Galway) proposed macromolecular crowding as means to create ECM-rich tissue equivalents. The principle of macromolecular crowding is derived from the notion that in vivo cells reside in a highly crowded/dense extracellular space and therefore the conversion of the de novo synthesised procollagen to collagen I is rapid. However, in the even substantially more dilute than body fluids (e.g., urine: 36–50 g/L; blood: 80 g/L) culture conditions (e.g., HAM F10 nutrient medium: 16.55 g/L; DMEM/ F12 medium: 16.78 g/L; DMEM high glucose and L-glutamine medium: 17.22 g/L), the rate limiting conversion of procollagen to collagen I is very slow. It was confirmed that the addition of inert polydispersed macromolecules (presented as spherical objects of variable diameter) in the culture media will facilitate amplified production of ECM-rich living substitutes. Macromolecular crowding, by imitating native tissue localised density, can be utilised to effectively modulate in vitro microenvironments and ultimately produce ECM-rich cell substitutes, within hours rather than days or months in culture, without compromising fundamental cellular functions. A recent study by researchers from the University of Twente has shown that emulating physiological molecular crowding may enhance chondrogenic properties of damaged chondrocytes. | 0 | Theoretical and Fundamental Chemistry |
TRH-stimulation testing however
continues to be useful for the differential diagnosis of secondary (pituitary disorder) and tertiary (hypothalamic disorder) hypothyroidism. Patients with these conditions
appear to have physiologically inactive TSH in their circulation that is recognized by
TSH assays to a degree such that they may yield misleading, "euthyroid" TSH
results. Use and Interpretation:
• Helpful in diagnosis in patients with confusing TFTs. In primary hyperthyroidism
TSH are low and TRH administration induces little or no change in TSH levels
• In hypothyroidism due to end organ failure, administration of TRH produces a
prompt increase in TSH
• In hypothyroidism due to pituitary disease (secondary hypothyroidism) administration of TRH does not produce
an increase in TSH
• In hypothyroidism due to hypothalamic disease (tertiary hypothyroidism), administration of TRH produces a
delayed (60–120 minutes, rather than 15–30 minutes) increase in TSH | 1 | Applied and Interdisciplinary Chemistry |
Eutrophication can occur naturally, during the late stage of the natural ecological succession that accompanies the infilling of a lake. It then develops slowly, over thousands of years. It develops within only a few decades when triggered by cropland fertilization, industrial contamination, or urban development. Deforestation, land fertilization, urbanization and industrialization in the catchment of lake Chichoj are all thought to have contributed in a way or the other to the massive lake contamination and eutrophication of the lake that has taken place since the 1950s. Degradation of its ecosystem motivated environmental studies starting in the 1970s. They aimed at documenting the eutrophication process, and at identifying its causes. Most concluded that the main source of eutrophication is the absence of treatment of city waste waters, rather than agriculture.
The most visible consequence of eutrophication is the massive development of large floating rafts of the water hyacinth (Eichhornia crassipes), which is untiringly harvested to prevent complete invasion of the lake open waters. The enormous amount of hyacinth removed from the lake is then composted to produce a horticultural fertilizer.
Many local witnesses have reported that the extensive marshes that surround the lake were open waters in the 1950s. The presence of a well marked shoreline 1.0 ± 0.1 to 1.4 ± 0.1 m above the average current lake level and surrounding the marshes supports these testimonies. Because eutrophication leads to rapid infilling of lakes by plant debris, and conversion of open waters to marshland, it has been hypothesized that eutrophication is responsible for the reduction in the lake surface.
Due to its location halfway between the Atlantic and Pacific Ocean, the lake ecosystem is normally influenced by the Pacific El Niño Oscillation (ENSO) and the North Atlantic Oscillation. Studies are under way to determine the sensitivity of the lake hydrology to these oscillations over the past millennium. | 1 | Applied and Interdisciplinary Chemistry |
CcrM (or M.CcrMI) is an orphan DNA methyltransferase, that is involved in controlling gene expression in most Alphaproteobacteria. This enzyme modifies DNA by catalyzing the transference of a methyl group from the S-adenosyl-L methionine substrate to the N6 position of an adenine base in the sequence 5-GANTC-3 with high specificity. In some lineages such as SAR11, the homologous enzymes possess 5-GAWTC-3 specificity. In Caulobacter crescentus Ccrm is produced at the end of the replication cycle when Ccrm recognition sites are hemimethylated, rapidly methylating the DNA. CcrM is essential in other Alphaproteobacteria but its role is not yet determined. CcrM is a highly specific methyltransferase with a novel DNA recognition mechanism. | 1 | Applied and Interdisciplinary Chemistry |
This originates from permanent and induced dipoles aligning to an electric field. Their orientation polarisation is disturbed by thermal noise (which mis-aligns the dipole vectors from the direction of the field), and the time needed for dipoles to relax is determined by the local viscosity. These two facts make dipole relaxation heavily dependent on temperature, pressure, and chemical surrounding. | 0 | Theoretical and Fundamental Chemistry |
There are some potential drawbacks for the palynological analysis of middens, however, as the diverse taphonomic vectors can complicate interpretations if they are not adequately considered and controlled for. Pollen spectra from pellets - reflecting the animal’s needs or preferences on a particular day - may contrast strongly with pollen spectra preserved in hyraceum, and which thought to be primarily brought to the midden via the fur of the hyraxes (which is collected as it moves through the vegetation around its shelter) and the wind. The degree to which dietary biases affect pollen spectra in pellets is a subject that is not fully understood. While Scott and Cooremans have shown that at the biome scale, fresh pellets reflect vegetation of the region from which they were collected, including the seasonal variations within vegetation types, most published studies also indicate significant differences both between modern pellets, and between modern pellets and surface sediment samples from the same site. A number of options might explain this, but it is assumed that as any given pellet represents what was eaten in the last day(s), there will be substantial inter-seasonal and inter-annual variation in the pollen preserved.
In most fossil pollen archives, wind-pollinated plants may dominate the natural pollen rain. Pollen production, however, is likely to have a less significant influence on the pollen that hyraxes ingest, and considering the wide variety of plants that they may eat, it may be possible to control for the taxon over-representation resulting from a production bias while still attaining a reasonable representation of the local vegetation.
A study from the Lower Omo Basin of Ethiopia collected several dozen pellets from different areas around the study site, aggregated them into a single sample, and compared them to the local vegetation.
Structured studies to clarify the relative influence of regional (aeolian) and local (fur) signals in the pollen preserved in hyraceum remain to be completed. At least in some cases, aeolian inputs appear to be negligible as some middens that have accumulated in vertical cracks - precluding the incorporation of pellets and direct contact with the animals - have been found to be devoid of pollen. If aeolian pollen does represent a small percentage of the pollen preserved in hyraceum then it might be inferred that hyraceum pollen assemblages reflect primarily local vegetation cover from within the animals’ primary feeding range. | 0 | Theoretical and Fundamental Chemistry |
For impure substances, e.g. alloys, honey, soft drink, ice cream, etc. the melting point broadens into a melting interval. If the temperature is within the melting interval, one may see "slurries" at equilibrium, i.e. the slurry will neither fully solidify nor melt. This is why new snow of high purity on mountain peaks either melts or stays solid, while dirty snow on the ground in cities tends to become slushy at certain temperatures. Weld melt pools containing high levels of sulfur, either from melted impurities of the base metal or from the welding electrode, typically have very broad melting intervals, which leads to increased risk of hot cracking. | 0 | Theoretical and Fundamental Chemistry |
Of academic interest, SO acts like a Lewis acid towards the alkyl ligand. The pathway for the insertion of SO into metal alkyl bond begins with attack of the alkyl nucleophile on the sulfur centre in SO. The "insertion" proceed the sulfur dioxide between the metal and the alkyl ligand leads to the O, O-sulphinate. Alternatively an O-sulphinate can arise. Both of these intermediates commonly convert to an S-sulphinate. S-sulphinate has sulfur–oxygen stretching frequencies from 1250–1000 cm and 1100–1000 cm. The O, O-sulphinate and O-sulphinate are difficult to distinguish as they have stretching frequencies from 1085–1050 cm and 1000–820 cm or lower. The pathway involving the O, O 'sulphinate can generally be ruled out if the original metal complex fulfilled the 18-electron rule because the two metal–oxygen bonds would exceed the 18 electron rule.
The pathway by which SO inserts into a square planar alkyl complexes involves the formation of an adduct. Thereafter, the alkyl ligand migrates to the SO. | 0 | Theoretical and Fundamental Chemistry |
Exposure studies in the copper smelting industry are much more extensive and have established definitive links between arsenic, a by-product of copper smelting, and lung cancer via inhalation. Dermal and neurological effects were also increased in some of these studies. Although as time went on, occupational controls became more stringent and workers were exposed to reduced arsenic concentrations, the arsenic exposures measured from these studies ranged from about 0.05 to 0.3 mg/m and are significantly higher than airborne environmental exposures to arsenic (which range from 0 to 0.000003 mg/m). | 1 | Applied and Interdisciplinary Chemistry |
In modern expansion joints, the metal bellows are often produced with a so-called multi-ply design. To increase both flexibility and stability, multiple thin plies of metal are layered to form the bellows walls. There are two basic design types: The multi-ply and the multi-walled bellows structure. The multi-ply structure consists of a pressure-tight, longitudinally welded outer and inner cylinder of stainless steel. In between these cylinders is an open, spiral cylinder which forms multiple plies depending on the design. The multi-walled structure consists of several concentric, longitudinally welded cylinders. Each cylinder forms a pressure-tight and closed "wall".
The main advantages of multi-walled bellows:
* Resistance to high and very high pressures
* Large movement absorption
* Small dimensions
* Small adjusting force rates
* Optimal compensation in a very small space
* Early leak indication (in case of damage) via standard check hole
* Complete burst resistance
*Possibility of permanent leak monitoring in critical media
* Economical use of high-quality, corrosion-resistant materials such as Inconel, Incoloy, Hastelloy, titanium and Tantal
* Insulation against structure-borne noise up to 20 dB
This design has both technical and economic advantages. For example, the bellows can be constructed of different materials, such as high-alloy stainless steels for the pipes in contact with the medium (inside and/or outside), and low-alloy stainless steels for the intermediate plies. | 1 | Applied and Interdisciplinary Chemistry |
; (1999 April);
Its an impressive memento which described the fascinating story of how his national team – Sri Lanka – blossomed out and established itself as International Champions of 1996/97 in Overs-limited cricket'. Perera has also captured here the brilliance, the philosophy and the pulsating drama of one-day internationals (ODIs) of that glorious period (1996–98) backed by highly informative and well tabulated appendices.
;Further Reading
* [https://web.archive.org/web/20100610050439/http://www.acumenbooks.co.uk/ajitintr.htm Sri Lanka were the Kings amongst Kings (1996–99)] Retrieved on 27 February 2009
* [http://sundaytimes.lk/011007/sportsm.html#s1LABEL3 Another masterpiece by Ajith Perera] Retrieved on 27 February 2009 | 0 | Theoretical and Fundamental Chemistry |
Viaspan was the trademark under which the University of Wisconsin cold storage solution (also known as University of Wisconsin solution or UW solution) was sold. Currently, UW solution is sold under the Belzer UW trademark and others like Bel-Gen or StoreProtect. UW solution was the first solution designed for use in organ transplantation, and became the first intracellular-like preservation medium. Developed in the late 1980s by Folkert Belzer and James Southard for pancreas preservation, the solution soon displaced EuroCollins solution as the preferred medium for cold storage of livers and kidneys, as well as pancreas. The solution has also been used for hearts and other organs. University of Wisconsin cold storage solution remains what is often called the gold standard for organ preservation, despite the development of other solutions that are in some respects superior. | 1 | Applied and Interdisciplinary Chemistry |
Because QCD is asymptotically free it becomes weakly coupled at unrealistically high densities, and diagrammatic
methods can be used. Such methods show that the CFL phase occurs at very high density. At high temperatures, however, diagrammatic methods are still not under full control. | 0 | Theoretical and Fundamental Chemistry |
The mechanism of the Kröhnke pyridine synthesis begins with enolization of α-pyridinium methyl ketone 4 followed by 1,4-addition to the α, β-unsaturated ketone 5 to form the Michael adduct 6, which immediately tautomerizes to the 1,5-dicarbonyl 7. Addition of ammonia to 7 followed by dehydration via 8 generates the imine intermediate 9., The imine intermediate is then deprotonated to enamine 10 and cyclizes with the carbonyl to generate intermediate 11. The pyridinium cation is then eliminated to form hydroxy-dienamine 12. Aromatization of 12 via subsequent loss of water generates the desired pyridine heterocycle 13. | 0 | Theoretical and Fundamental Chemistry |
The targets used in neutron generators are thin films of metal such as titanium, scandium, or zirconium which are deposited onto a silver, copper or molybdenum substrate. Titanium, scandium, and zirconium form stable chemical compounds called metal hydrides when combined with hydrogen or its isotopes. These metal hydrides are made up of two hydrogen (deuterium or tritium) atoms per metal atom and allow the target to have extremely high densities of hydrogen. This is important to maximize the neutron yield of the neutron tube. The gas reservoir element also uses metal hydrides, e.g. uranium hydride, as the active material.
Titanium is preferred to zirconium as it can withstand higher temperatures (200 °C), and gives higher neutron yield as it captures deuterons better than zirconium. The maximum temperature allowed for the target, above which hydrogen isotopes undergo desorption and escape the material, limits the ion current per surface unit of the target; slightly divergent beams are therefore used. A 1 microampere ion beam accelerated at 200 kV to a titanium-tritium target can generate up to 10 neutrons per second. The neutron yield is mostly determined by the accelerating voltage and the ion current level.
An example of a tritium target in use is a 0.2 mm thick silver disc with a 1 micrometer layer of titanium deposited on its surface; the titanium is then saturated with tritium.
Metals with sufficiently low hydrogen diffusion can be turned into deuterium targets by bombardment of deuterons until the metal is saturated. Gold targets under such condition show four times higher efficiency than titanium. Even better results can be achieved with targets made of a thin film of a high-absorption high-diffusivity metal (e.g. titanium) on a substrate with low hydrogen diffusivity (e.g. silver), as the hydrogen is then concentrated on the top layer and can not diffuse away into the bulk of the material. Using a deuterium-tritium gas mixture, self-replenishing D-T targets can be made. The neutron yield of such targets is lower than of tritium-saturated targets in deuteron beams, but their advantage is much longer lifetime and constant level of neutron production. Self-replenishing targets are also tolerant to high-temperature bake-out of the tubes, as their saturation with hydrogen isotopes is performed after the bakeout and tube sealing. | 0 | Theoretical and Fundamental Chemistry |
An important feature of water is its polar nature. The structure has a bent molecular geometry for the two hydrogens from the oxygen vertex. The oxygen atom also has two lone pairs of electrons. One effect usually ascribed to the lone pairs is that the H–O–H gas-phase bend angle is 104.48°, which is smaller than the typical tetrahedral angle of 109.47°. The lone pairs are closer to the oxygen atom than the electrons sigma bonded to the hydrogens, so they require more space. The increased repulsion of the lone pairs forces the O–H bonds closer to each other.
Another consequence of its structure is that water is a polar molecule. Due to the difference in electronegativity, a bond dipole moment points from each H to the O, making the oxygen partially negative and each hydrogen partially positive. A large molecular dipole, points from a region between the two hydrogen atoms to the oxygen atom. The charge differences cause water molecules to aggregate (the relatively positive areas being attracted to the relatively negative areas). This attraction, hydrogen bonding, explains many of the properties of water, such as its solvent properties.
Although hydrogen bonding is a relatively weak attraction compared to the covalent bonds within the water molecule itself, it is responsible for several of the waters physical properties. These properties include its relatively high melting and boiling point temperatures: more energy is required to break the hydrogen bonds between water molecules. In contrast, hydrogen sulfide (), has much weaker hydrogen bonding due to sulfurs lower electronegativity. is a gas at room temperature, despite hydrogen sulfide having nearly twice the molar mass of water. The extra bonding between water molecules also gives liquid water a large specific heat capacity. This high heat capacity makes water a good heat storage medium (coolant) and heat shield. | 1 | Applied and Interdisciplinary Chemistry |
Leading experts in the field have supported a proposal for a Global Project on Artificial Photosynthesis as a combined energy security and climate change solution.
Conferences on this theme have been held at Lord Howe Island during 2011, at Chicheley Hall in the UK in 2014 and at Canberra and Lord Howe island during 2016. | 0 | Theoretical and Fundamental Chemistry |
RAI1 is a transcription factor associated with Smith–Magenis syndrome when individuals have deletions of the gene and Potocki–Lupski syndrome when individuals have a duplication. It is known as retinoic acid induced 1. | 1 | Applied and Interdisciplinary Chemistry |
BREEAM has expanded from its original focus on individual new buildings at the construction stage to encompass the whole life cycle of buildings from planning to in-use and refurbishment. Its regular revisions and updates are driven by the ongoing need to improve sustainability, respond to feedback from industry and support the UK's sustainability strategies and commitments.
Highly flexible, the BREEAM standard can be applied to virtually any building and location, with versions for new buildings, existing buildings, refurbishment projects and large developments:
BREEAM New Construction is the BREEAM standard against which the sustainability of new, non-residential buildings in the UK is assessed. Developers and their project teams use the scheme at key stages in the design and procurement process to measure, evaluate, improve and reflect the performance of their buildings.
BREEAM International New Construction is the BREEAM standard for assessing the sustainability of new residential and non-residential buildings in countries around the world, except for the UK and other countries with a national BREEAM scheme (see below). This scheme makes use of assessment criteria that take account of the circumstances, priorities, codes and standards of the country or region in which the development is located.
BREEAM In-Use is a scheme to help building managers reduce the running costs and improve the environmental performance of existing buildings. It has two parts: building asset and building management. Both parts are relevant to all non-domestic, commercial, industrial, retail and institutional buildings. BREEAM In-Use is widely used by members of the International Sustainability Alliance (ISA), which provides a platform for certification against the scheme. The newest version v6, available from 2020 includes also Residential programs.
BREEAM Refurbishment provides a design and assessment method for sustainable housing refurbishment projects, helping to cost-effectively improve the sustainability and environmental performance of existing dwellings in a robust way. A scheme for non-housing refurbishment projects is being developed and is targeted for launch in early 2014. The launch date will be announced once the piloting and independent peer review processes has been completed.
BREEAM Communities focuses on the masterplanning of whole communities. It is aimed at helping construction industry professionals to design places that people want to live and work in, are good for the environment and are economically successful.
BREEAM includes several general sustainability categories for the assessment:
* Management
* Energy
* Health and wellbeing
* Transport
* Water
* Materials
* Waste
* Land use and ecology
* Pollution
Home Quality Mark was launched in 2015 as part of the BREEAM family of schemes. It rates new homes on their overall quality and sustainability, then provides further indicators on the homes impact upon the occupants Running costs, Health and wellbeing and Environmental footprint. | 1 | Applied and Interdisciplinary Chemistry |
The use of lead arsenate pesticides has been effectively eliminated for over 50 years. However, because of the pesticide's environmental persistence, it is estimated that millions of acres of land are still contaminated with lead arsenate residues. This presents a potentially significant public health concern in some areas of the United States (e.g., New Jersey, Washington, and Wisconsin), where large areas of land used historically as orchards have been converted into residential developments.
Some modern uses of arsenic-based pesticides still exist. Chromated copper arsenate has been registered for use in the United States since the 1940s as a wood preservative, protecting wood from insects and microbial agents. In 2003, manufacturers of chromated copper arsenate instituted a voluntary recall of residential uses of wood treated with the chemical. The Environmental Protection Agency Act 2008 final report stated that chromated copper arsenate is still approved for use in nonresidential applications, such as in marine facilities (pilings and structures), utility poles, and sand highway structures. | 1 | Applied and Interdisciplinary Chemistry |
Most soft nanoparticles have core–shell structures. The semiflexible surface ligands soften the interaction of the cores and create a more spherical shape than the underlying core from uniform coverage. The surface ligands can be chosen from surfactants, polymers, DNA, ions, etc. Tuning the structure of superlattices can be achieved by varying the amount of surface ligands. Their “soft” behavior results in different self-assembly rules from hard particles, where Pauling’s rules expired.
To tailor the superlattice structure of soft nanoparticles, six design rules of spherical nanoparticle superlattice are established based on the study of metal–DNA nanoparticles: | 0 | Theoretical and Fundamental Chemistry |
The primary use of this reagent is for detecting secondary amines, such as MDMA and methamphetamine, and is typically used after the mecke or marquis reagents to differentiate between the two mentioned and amphetamine or MDA. | 0 | Theoretical and Fundamental Chemistry |
Although E varies greatly across the periodic table, some patterns emerge. Generally, nonmetals have more positive E than metals. Atoms whose anions are more stable than neutral atoms have a greater E. Chlorine most strongly attracts extra electrons; neon most weakly attracts an extra electron. The electron affinities of the noble gases have not been conclusively measured, so they may or may not have slightly negative values.
E generally increases across a period (row) in the periodic table prior to reaching group 18. This is caused by the filling of the valence shell of the atom; a group 17 atom releases more energy than a group 1 atom on gaining an electron because it obtains a filled valence shell and therefore is more stable. In group 18, the valence shell is full, meaning that added electrons are unstable, tending to be ejected very quickly.
Counterintuitively, E does not decrease when progressing down most columns of the periodic table. For example, E actually increases consistently on descending the column for the group 2 data. Thus, electron affinity follows the same "left-right" trend as electronegativity, but not the "up-down" trend.
The following data are quoted in kJ/mol. | 0 | Theoretical and Fundamental Chemistry |
* 1723 - Moritz Anton Cappeller introduced the term ‘crystallography’.
* 1766 - Pierre-Joseph Macquer, in his Dictionnaire de Chymie, promoted mechanisms of crystallization based on the idea that crystals are composed of polyhedral molecules (primitive integrantes).
* 1772 - Jean-Baptiste L. Romé de lIsle developed geometrical ideas on crystal structure in his Essai de Cristallographie'. He also described the twinning phenomenon in crystals.
* 1781 - Abbé René Just Haüy (often termed the "Father of Modern Crystallography") discovered that crystals always cleave along crystallographic planes. Based on this observation, and the fact that the inter-facial angles in each crystal species always have the same value, Haüy concluded that crystals must be periodic and composed of regularly arranged rows of tiny polyhedra (molécules intégrantes). This theory explained why all crystal planes are related by small rational numbers (the law of rational indices).
* 1783 - Jean-Baptiste L. Romé de lIsle in the second edition of his Cristallographie' used the contact goniometer to discover the law of constant interfacial angles: angles are constant and characteristic for crystals of the same chemical substance.
* 1784 - René Just Haüy published his Law of Decrements: a crystal is composed of molecules arranged periodically in three dimensions.
* 1795 - René Just Haüy lectured on his Law of Symmetry: “[…] the manner in which Nature creates crystals is always obeying [...] the law of the greatest possible symmetry, in the sense that oppositely situated but corresponding parts are always equal in number, arrangement, and form of their faces”. | 1 | Applied and Interdisciplinary Chemistry |
In molecular biology, an amplicon is a piece of DNA or RNA that is the source and/or product of amplification or replication events. It can be formed artificially, using various methods including polymerase chain reactions (PCR) or ligase chain reactions (LCR), or naturally through gene duplication. In this context, amplification refers to the production of one or more copies of a genetic fragment or target sequence, specifically the amplicon. As it refers to the product of an amplification reaction, amplicon is used interchangeably with common laboratory terms, such as "PCR product."
Artificial amplification is used in research, forensics, and medicine for purposes that include detection and quantification of infectious agents, identification of human remains, and extracting genotypes from human hair.
Natural gene duplication plays a major role in evolution. It is also implicated in several forms of human cancer including primary mediastinal B cell lymphoma and Hodgkins lymphoma. In this context the term amplicon' can refer both to a section of chromosomal DNA that has been excised, amplified, and reinserted elsewhere in the genome, and to a fragment of extrachromosomal DNA known as a double minute, each of which can be composed of one or more genes. Amplification of the genes encoded by these amplicons generally increases transcription of those genes and ultimately the volume of associated proteins. | 1 | Applied and Interdisciplinary Chemistry |
The use of swales has been popularized as a rainwater-harvesting and soil-conservation strategy by Bill Mollison, David Holmgren, and other advocates of permaculture. In this context a swale is usually a water-harvesting ditch on contour, also called a contour bund.
Swales as used in permaculture are designed by permaculturalists to slow and capture runoff by spreading it horizontally across the landscape (along an elevation contour line), facilitating runoff infiltration into the soil. This archetypal form of swale is a dug-out, sloped, often grassed or "ditch" or "lull" in the landform. One option involves piling the soil onto a new bank on the still lower slope, in which case a bund or berm is formed, mitigating the natural (and often hardscape-increased) risks to slopes below and to any linked watercourse from flash flooding.
In arid and seasonally dry places, vegetation (existing or planted) in the swale benefits heavily from the concentration of runoff. Trees and shrubs along the swale can provide shade and mulch which decrease evaporation. | 1 | Applied and Interdisciplinary Chemistry |
The speed of sound is variable and depends on the properties of the substance through which the wave is travelling. In solids, the speed of transverse (or shear) waves depends on the shear deformation under shear stress (called the shear modulus), and the density of the medium. Longitudinal (or compression) waves in solids depend on the same two factors with the addition of a dependence on compressibility.
In fluids, only the medium's compressibility and density are the important factors, since fluids do not transmit shear stresses. In heterogeneous fluids, such as a liquid filled with gas bubbles, the density of the liquid and the compressibility of the gas affect the speed of sound in an additive manner, as demonstrated in the hot chocolate effect.
In gases, adiabatic compressibility is directly related to pressure through the heat capacity ratio (adiabatic index), while pressure and density are inversely related to the temperature and molecular weight, thus making only the completely independent properties of temperature and molecular structure important (heat capacity ratio may be determined by temperature and molecular structure, but simple molecular weight is not sufficient to determine it).
Sound propagates faster in low molecular weight gases such as helium than it does in heavier gases such as xenon. For monatomic gases, the speed of sound is about 75% of the mean speed that the atoms move in that gas.
For a given ideal gas the molecular composition is fixed, and thus the speed of sound depends only on its temperature. At a constant temperature, the gas pressure has no effect on the speed of sound, since the density will increase, and since pressure and density (also proportional to pressure) have equal but opposite effects on the speed of sound, and the two contributions cancel out exactly. In a similar way, compression waves in solids depend both on compressibility and density—just as in liquids—but in gases the density contributes to the compressibility in such a way that some part of each attribute factors out, leaving only a dependence on temperature, molecular weight, and heat capacity ratio which can be independently derived from temperature and molecular composition (see derivations below). Thus, for a single given gas (assuming the molecular weight does not change) and over a small temperature range (for which the heat capacity is relatively constant), the speed of sound becomes dependent on only the temperature of the gas.
In non-ideal gas behavior regimen, for which the Van der Waals gas equation would be used, the proportionality is not exact, and there is a slight dependence of sound velocity on the gas pressure.
Humidity has a small but measurable effect on the speed of sound (causing it to increase by about 0.1%–0.6%), because oxygen and nitrogen molecules of the air are replaced by lighter molecules of water. This is a simple mixing effect. | 1 | Applied and Interdisciplinary Chemistry |
MIKE 21 can be used for design data assessment for coastal and offshore structures, optimization of port layout and coastal protection measures, cooling water, desalination and recirculation analysis, environmental impact assessment of marine infrastructures, water forecast for safe marine operations and navigation, coastal flooding and storm surge warnings, inland flooding and overland flow modeling. | 1 | Applied and Interdisciplinary Chemistry |
Detonation spraying is one of the many forms of thermal spraying techniques that are used to apply a protective coating at supersonic velocities to a material in order to change its surface characteristics. This is primarily to improve the durability of a component. It was first invented in 1955 by H.B. Sargent, R.M. Poorman and H. Lamprey and is applied to a component using a specifically designed detonation gun (D-gun). The component being sprayed must be prepared correctly by removing all surface oils, greases, debris and roughing up the surface in order to achieve a strongly bonded detonation spray coating. This process involves the highest velocities (≈3500 m/s shockwave that propels the coating materials) and temperatures (≈4000 °C) of coating materials compared to all other forms of thermal spraying techniques. Which means detonation spraying is able to apply low porous (below 1%) and low oxygen content (between 0.1 and 0.5%) protective coatings that protect against corrosion, abrasion and adhesion under low load.
This process allows the application of very hard and dense surface coatings which are useful as wear resistant coatings. For this reason, detonation spraying is commonly used for protective coatings in aircraft engines, plug and ring gauges, cutting edges (skiving knives), tubular drills, rotor and stator blades, guide rails or any other metallic material that is subject to high wear and tear. Commonly the materials that are sprayed onto components during detonation spraying are powders of metals, metal alloys and cermets; as well as their oxides (aluminum, copper, iron, etc.).
Detonation spraying is an industrial process that can be dangerous if not performed correctly and in a safe environment. As such there are many safety precautions that must be adhered to when using this thermal spraying technique. | 1 | Applied and Interdisciplinary Chemistry |
Rigorously, the oscillation is periodic only at . Indeed, in the realization of the Toda oscillator as a self-pulsing laser, these parameters may have values of order of ; during several pulses, the amplitude of pulsation does not change much. In this case, we can speak about the period of pulsation, since the function is almost periodic.
In the case , the energy of the oscillator does not depend on , and can be treated as a constant of motion. Then, during one period of pulsation, the relation between and can be expressed analytically:
where
and are minimal and maximal values of ; this solution is written for the case when .
however, other solutions may be obtained using the principle of translational invariance.
The ratio is a convenient parameter to characterize the amplitude of pulsation. Using this, we can express the median value
as
and the energy
is also an elementary function of .
In application, the quantity need not be the physical energy of the system; in these cases, this dimensionless quantity may be called quasienergy. | 0 | Theoretical and Fundamental Chemistry |
A number of examples of molecular mimicry by pathogens, emulating natural endogenous ligands of paired receptors for immune evasion, have been described in the literature. Such interactions are particularly common with the inhibitory members of receptor pairs, bolstering the hypothesis that activating partners are a later evolutionary response to this immune escape strategy.
The first described interaction between a paired receptor and a viral protein identified ILT-2 and ILR-4 (LILRB1 and LILRB2) as targets for herpes simplex virus UL18 protein, which resembles an MHC-I molecule. Variations in susceptibility to mouse cytomegalovirus infection due to differences in Ly49-family paired receptors among mouse strains are well-characterized, and are attributed to the structural resemblance between the viral protein m157 and MHC-I molecules. The pathogenic bacterium Escherichia coli K1 exposes surface polysialic acid molecules that serve as a molecular mimic for the native ligand of the inhibitory receptor Siglec-11, but induces an opposing response through interactions with the paired activating receptor Siglec-16, exemplifying the benefit of activating receptors as defense mechanisms against molecular mimicry by pathogens.
Paired receptors are also used as viral entry receptors by a number of viruses and occasionally as entry mechanisms for other pathogens. Sialylation is common among mammalian cell-surface proteins and a number of pathogens use sialic acid - either self-synthesized or obtained from the host cell - to evade host immunity, including by interacting with inhibitory siglec receptors. | 1 | Applied and Interdisciplinary Chemistry |
MODOMICS is a comprehensive database that contains information about RNA modifications. MODOMICS provides the following information: the chemical structure of the modified RNAs, the RNA modifying pathways, the location of the modifications in the RNA sequences, the enzymes responsible for the modifications and liquid chromatography/mass spectrometry(LC/MS) data of the modified RNAs. As of November 2017, the database contained 163 different RNA modifications, as well as 340 different enzymes and cofactors involved in the modifications. This database classifies RNA modifying pathways according to their starting point. The LC/MS data has been very useful in determining the specific mass of the modified RNAs, which facilitates the identification of the modification. | 1 | Applied and Interdisciplinary Chemistry |
The key elements of any FOCE experimental units are perspex, partially open, chambers, a CO mixing system, sensors to continuously monitor ambient and chamber pH, and a control loop to regulate the addition of gases or liquids to each experimental chamber.
The carbonate chemistry of seawater can be manipulated using different approaches to mimic future conditions. It is possible to directly inject gases (pure CO or CO-enriched air) but this is more difficult than delivering water to achieve precise pH control. Current FOCE systems lower pH using metered addition of CO-enriched seawater into the experimental chambers. pH is controlled as a constant pH offset relative to ambient values, maintaining natural variability, or as a constant value.
Other approaches have been used to manipulate the seawater carbonate chemistry in the field. In pelagic mesocosm experiments, the carbonate chemistry is generally altered at the beginning of the experiment and subsequently drifts as a function of biological processes and air-sea gas transfer. CO bubbling in open water has also been used. This approach does not enable precise control of the carbonate chemistry because it does not include a device to ensure full equilibration of added CO in seawater and its precise control. There are no experimental chambers to regulate water flow, and thus allows for natural near-bottom flow conditions, but it generates highly variable pH under variable current speed or direction. This approach is therefore more similar to natural CO vents than to FOCE systems. This approach can be useful when organisms can not be enclosed in chambers and when they inhabit environments such as estuaries where pCO2 levels are naturally hyper-variable. The approach has inherent limitations but may allow greater replication, at lower cost.
Current users of FOCE systems have organized to release guidelines and best practices information for future users. Furthermore, the Monterey Bay Aquarium Research Institute will release an open source package to transfer FOCE technology to interested researchers ([http://www.xfoce.org xFOCE]). This package will comprise all engineering information required to develop cost effective FOCE systems.
Future development of FOCE systems will include the study of the combined effects of ocean acidification and other environmental factors such as temperature or the concentration of dissolved oxygen. | 0 | Theoretical and Fundamental Chemistry |
Ro60 is not part of the TRIM family. Ro60 is encoded by a gene 32 kb in length and acts to regulate the fate of misfolded RNA within the host cell. Ro60 forms a ribonucleoprotein complex with one molecule of noncoding Y1, Y3, Y4, or Y5RNA, all of which are approximately 100 nucleotides in length, to form the epitope that Anti-Ro60 recognizes. The absence of Ro60 results in an elevated immune response and decreased resilience to immune-related stress.
The epitope of the Ro60 protein is similar to that of the Epstein-Barr virus, and the presence of the virus may enhance the autoimmune response to Ro60, as anti-Epstein Barr antibodies can target the protein. | 1 | Applied and Interdisciplinary Chemistry |
Critical Path Institute (C-Path) is a non-profit organization created to improve the drug development process; its consortia include more than 1,600 scientists from government regulatory and research agencies, academia, patient organizations, and bio-pharmaceutical companies. | 1 | Applied and Interdisciplinary Chemistry |
During its formation, the Earth likely suffered a series of magma oceans resulting from giant impacts, the final one being the Moon-forming impact. The best chemical evidence for the existence of magma oceans on Earth is the abundance of certain siderophile elements in the mantle that record magma ocean depths of approximately 1000 km during accretion. The scientific evidence to support the existence of magma oceans on early Earth is not as developed as the evidence for the Moon because of the recycling of the Earth's crust and mixing of the mantle. Unlike Earth, indications of a magma ocean on the Moon such as the flotation crust, elemental components in rocks, and KREEP have been preserved throughout its lifetime.
Today Earths outer core is a liquid layer about thick, composed mostly of molten iron and molten nickel that lies above Earths solid inner core and below its mantle. This layer may be considered as an ocean of molten iron and nickel inside Earth. | 0 | Theoretical and Fundamental Chemistry |
Arylsulfatase (EC 3.1.6.1, sulfatase, nitrocatechol sulfatase, phenolsulfatase, phenylsulfatase, p-nitrophenyl sulfatase, arylsulfohydrolase, 4-methylumbelliferyl sulfatase, estrogen sulfatase) is a type of sulfatase enzyme with systematic name aryl-sulfate sulfohydrolase. This enzyme catalyses the following chemical reaction
: an aryl sulfate + HO a phenol + sulfate
It catalyses an analogous reaction for sulfonated hexoses. Types include:
*Arylsulfatase A (also known as "cerebroside-sulfatase")
*Arylsulfatase B (also known as "N-acetylgalactosamine-4-sulfatase")
*Steroid sulfatase (formerly known as "arylsulfatase C")
*ARSC2
*ARSD
*ARSF
*ARSG
*ARSH
*ARSI
*ARSJ
*ARSK
*ARSL (formerly known as "arylsulfatase E", "ARSE") | 1 | Applied and Interdisciplinary Chemistry |
Paul Benjamin Ferrara (November 2, 1942 – May 30, 2011) was a scientist and administrator who pioneered the use of DNA profiling in America. | 0 | Theoretical and Fundamental Chemistry |
Glyoxylate and dicarboxylate metabolism describes a variety of reactions involving glyoxylate or dicarboxylates. Glyoxylate is the conjugate base of glyoxylic acid, and within a buffered environment of known pH such as the cell cytoplasm these terms can be used almost interchangeably, as the gain or loss of a hydrogen ion is all that distinguishes them, and this can occur in the aqueous environment at any time. Likewise dicarboxylates are the conjugate bases of dicarboxylic acids, a general class of organic compounds containing two carboxylic acid groups, such as oxalic acid or succinic acid.
A compact graphical description of major biochemical reactions involved can be found at KEGG This provides information on the relevant enzymes and details the relationship with several other metabolic processes: glycine, serine, and threonine metabolism which provides hydroxypyruvate and glyoxylate, purine metabolism which provides glyoxylate, pyruvate metabolism which provides (S)-malate and formate, carbon fixation which consumes 3-phospho-D-glycerate and provides D-ribulose 1,5-P2, ascorbate and aldarate metabolism which shares tartronate-semialdehyde, nitrogen metabolism which shares formate, pyruvate metabolism and the citrate cycle which share oxaloacetate, and vitamin B metabolism which consumes glycolaldehyde.
The glyoxylate cycle describes an important subset of these reactions involved in biosynthesis of carbohydrates from fatty acids or two-carbon precursors which enter the system as acetyl-coenzyme A. Its crucial enzymes are isocitrate lyase and malate synthase. However, alternate pathways have been proposed in organisms lacking isocitrate lyase. | 1 | Applied and Interdisciplinary Chemistry |
He was also a top expert in the field of archaeometry. He pioneered high-precision methods of neutron activation analysis at the Lawrence Berkeley Laboratory in the US. Neutron activation analysis helps to determine the origin of ancient pottery and other artifacts through the analysis of the clay from which they were made. He was helped in the project by another noted scientist Frank Asaro. Second millennium BC pottery known as Cypriot Bichrome ware was one of the first archaeological projects that Perlman and Asaro undertook. | 0 | Theoretical and Fundamental Chemistry |
In Rutherford scattering, an incident particle with charge and energy scatters off a fixed particle with charge . The differential cross section is
where is the Coulomb constant. The total cross section is infinite unless a cutoff for small scattering angles is applied. This is due to the long range of the Coulomb potential. | 0 | Theoretical and Fundamental Chemistry |
Uranium is a natural metal which is widely found. It is present in almost all soils and it is more plentiful than antimony, beryllium, cadmium, gold, mercury, silver, or tungsten, and is about as abundant as arsenic or molybdenum. Significant concentrations of uranium occur in some substances such as phosphate rock deposits, and minerals such as lignite, and monazite sands in uranium-rich ores (it is recovered commercially from these sources).
Seawater contains about 3.3 parts per billion of uranium by weight as uranium (VI) forms soluble carbonate complexes. Extraction of uranium from seawater has been considered as a means of obtaining the element. Because of the very low specific activity of uranium the chemical effects of it upon living things can often outweigh the effects of its radioactivity. Additional uranium has been added to the environment in some locations, from the nuclear fuel cycle and the use of depleted uranium in munitions. | 0 | Theoretical and Fundamental Chemistry |
Transmetalation is often used as a step in the catalytic cycles of cross-coupling reactions. Some of the cross-coupling reactions that include a transmetalation step are Stille cross-coupling, Suzuki cross-coupling, Sonogashira cross-coupling, and Negishi cross-coupling. The most useful cross-coupling catalysts tend to be ones that contain palladium. Cross-coupling reactions have the general form of R′–X + M–R → R′–R + M–X and are used to form C–C bonds. R and R′ can be any carbon fragment. The identity of the metal, M, depends on which cross-coupling reaction is being used. Stille reactions use tin, Suzuki reactions use boron, Sonogashira reactions use copper, and Negishi reactions use zinc. The transmetalation step in palladium catalyzed reactions involve the addition of an R–M compound to produce an R′–Pd–R compound. Cross-coupling reactions have a wide range of applications in synthetic chemistry including the area of medicinal chemistry. The Stille reaction has been used to make an antitumor agent, (±)-epi-jatrophone; the Suzuki reaction has been used to make an antitumor agent, oximidine II; the Sonogashira reaction has been used to make an anticancer drug, eniluracil; and the Negishi reaction has been used to make the carotenoid β-carotene via a transmetalation cascade. | 0 | Theoretical and Fundamental Chemistry |
A double-blind comparator-controlled Phase I/II clinical trial of using D-linoleic acid ethyl ester (RT001) for Friedreichs ataxia, sponsored by Retrotope and Friedreichs Ataxia Research Alliance, was conducted to determine the safety profile and appropriate dosing for consequent trials. RT001 was promptly absorbed and was found to be safe and tolerable over 28 days at the maximal dose of 9 g/day. It improved peak workload and peak oxygen consumption in the test group compared to the control group who received the equal doses of normal, non-deuterated linoleic acid ethyl ester. Another randomised, double-blind, placebo-controlled clinical study began in 2019. | 1 | Applied and Interdisciplinary Chemistry |
Carbonatation is a chemical reaction in which calcium hydroxide reacts with carbon dioxide and forms insoluble calcium carbonate:
The process of forming a carbonate is sometimes referred to as "carbonation", although this term usually refers to the process of dissolving carbon dioxide in water. | 0 | Theoretical and Fundamental Chemistry |
Throughout the recommendations the use of the electronegativity of elements for sequencing has been replaced by a formal list which is loosely based on electronegativity. The recommendations still use the terms electropositive and electronegative to refer to an element's relative position in this list.
A simple rule of thumb ignoring lanthanides and actinides is:
*for two elements in different groups—then the element in the higher numbered group has higher "electronegativity"
*for two elements within the same group the element with the lower the atomic number has the higher "electronegativity"
*Hydrogen is fitted in to be less electronegative than any chalcogen and more electronegative than any pnictogen. Hence the formulae of water and ammonia can be written HO and NH respectively.
The full list, from highest to lowest "electronegativity" (with the addition of elements 112 through 118, that had not yet been named in 2005, to their respective groups):
*Group 17 in atomic number sequence i.e. F–Ts followed by
*Group 16 in atomic number sequence i.e. O–Lv followed by
* H, hydrogen, followed by
* Group 15 in atomic number sequence i.e. N–Mc followed by
* Group 14 in atomic number sequence i.e. C–Fl followed by
* Group 13 in atomic number sequence i.e. B–Nh followed by
* Group 12 in atomic number sequence i.e. Zn–Cn followed by
* Group 11 in atomic number sequence i.e. Cu–Rg followed by
* Group 10 in atomic number sequence i.e. Ni–Ds followed by
* Group 9 in atomic number sequence i.e. Co–Mt followed by
* Group 8 in atomic number sequence i.e. Fe–Hs followed by
* Group 7 in atomic number sequence i.e. Mn–Bh followed by
* Group 6 in atomic number sequence i.e. Cr–Sg followed by
* Group 5 in atomic number sequence i.e. V–Db followed by
* Group 4 in atomic number sequence i.e. Ti–Rf followed by
* Group 3 in atomic number sequence i.e. Sc–Y followed by
* the lanthanoids in atomic number sequence i.e. La–Lu followed by
* the actinoids in atomic number sequence i.e. Ac–Lr followed by
* Group 2 in atomic number sequence i.e. Be–Ra followed by
* Group 1 (excluding H) in atomic number sequence i.e. Li–Fr followed by
* Group 18 in atomic number sequence i.e. He–Og | 0 | Theoretical and Fundamental Chemistry |
Amyloid-beta precursor protein is an ancient and highly conserved protein. In humans, the gene APP is located on chromosome 21 and contains 18 exons spanning 290 kilobases. Several alternative splicing isoforms of APP have been observed in humans, ranging in length from 639 to 770 amino acids, with certain isoforms preferentially expressed in neurons; changes in the neuronal ratio of these isoforms have been associated with Alzheimers disease. Homologous proteins have been identified in other organisms such as Drosophila (fruit flies), C. elegans (roundworms), and all mammals. The amyloid beta region of the protein, located in the membrane-spanning domain, is not well conserved across species and has no obvious connection with APPs native-state biological functions.
Mutations in critical regions of amyloid precursor protein, including the region that generates amyloid beta (Aβ), cause familial susceptibility to Alzheimers disease. For example, several mutations outside the Aβ region associated with familial Alzheimers have been found to dramatically increase production of Aβ.
A mutation (A673T) in the APP gene protects against Alzheimer's disease. This substitution is adjacent to the beta secretase cleavage site and results in a 40% reduction in the formation of amyloid beta in vitro. | 1 | Applied and Interdisciplinary Chemistry |
Herons siphon is not a siphon as it works as a gravity driven pressure pump, at first glance it appears to be a perpetual motion machine but will stop when the air in the priming pump is depleted. In a slightly differently configuration, it is also known as Herons fountain. | 1 | Applied and Interdisciplinary Chemistry |
Typical titrations require titrant and analyte to be in a liquid (solution) form. Though solids are usually dissolved into an aqueous solution, other solvents such as glacial acetic acid or ethanol are used for special purposes (as in petrochemistry, which specializes in petroleum.) Concentrated analytes are often diluted to improve accuracy.
Many non-acid–base titrations require a constant pH during the reaction. Therefore, a buffer solution may be added to the titration chamber to maintain the pH.
In instances where two reactants in a sample may react with the titrant and only one is the desired analyte, a separate masking solution may be added to the reaction chamber which eliminates the effect of the unwanted ion.
Some reduction-oxidation (redox) reactions may require heating the sample solution and titrating while the solution is still hot to increase the reaction rate. For instance, the oxidation of some oxalate solutions requires heating to to maintain a reasonable rate of reaction. | 0 | Theoretical and Fundamental Chemistry |
Ammonium perfluorononanoate (APFN) is an anionic surfactant that in water forms liquid crystalline phases (Lyotropic liquid crystal). It is the ammonium salt of perfluorononanoic acid.
The phase diagram of APFN/HO system is delineated by the presence of a lamellar phase and a nematic phase with awide isotropic solution. The nematic phase is of the type I, and the aggregates have a positive and diamagnetic anisotropy. In the presence of a magnetic field, the aggregates align parallel to the field direction. The change of phase at the lamellar-nematic temperature has been ascribed to order-disorder transitions. | 0 | Theoretical and Fundamental Chemistry |
Urea was first noticed by Herman Boerhaave in the early 18th century from evaporates of urine. In 1773, Hilaire Rouelle obtained crystals containing urea from human urine by evaporating it and treating it with alcohol in successive filtrations. This method was aided by Carl Wilhelm Scheeles discovery that urine treated by concentrated nitric acid precipitated crystals. Antoine François, comte de Fourcroy and Louis Nicolas Vauquelin discovered in 1799 that the nitrated crystals were identical to Rouelles substance and invented the term "urea." Berzelius made further improvements to its purification and finally William Prout, in 1817, succeeded in obtaining and determining the chemical composition of the pure substance. In the evolved procedure, urea was precipitated as urea nitrate by adding strong nitric acid to urine. To purify the resulting crystals, they were dissolved in boiling water with charcoal and filtered. After cooling, pure crystals of urea nitrate form. To reconstitute the urea from the nitrate, the crystals are dissolved in warm water, and barium carbonate added. The water is then evaporated and anhydrous alcohol added to extract the urea. This solution is drained off and evaporated, leaving pure urea. | 0 | Theoretical and Fundamental Chemistry |
The Irving Langmuir Prize in Chemical Physics is awarded annually, in even years by the American Chemical Society and in odd years by the American Physical Society. The award is meant to recognize and encourage outstanding interdisciplinary research in chemistry and physics, in the spirit of Irving Langmuir. A nominee must have made an outstanding contribution to chemical physics or physical chemistry within the 10 years preceding the year in which the award is made. The award will be granted without restriction, except that the recipient must be a resident of the United States.
The award was established in 1931 by Dr. A.C. Langmuir, brother of Nobel Prize-winning chemist Irving Langmuir, to recognize the best young chemist in the United States. A $10,000 prize was to be awarded annually by the American Chemical Society. The first recipient was Linus Pauling. In 1964, the General Electric Foundation took over the financial backing of the prize, which was renamed the Irving Langmuir Award and the modern selection process was created. In 2006 the GE Global Research took over sponsorship of the award, and since 2009 the award has been co-sponsored between GE Global Research and the ACS Division of Physical Chemistry. | 0 | Theoretical and Fundamental Chemistry |
Coarse bubble diffusers are a pollution control technology used to aerate and or mix wastewater for sewage treatment. | 1 | Applied and Interdisciplinary Chemistry |
EosFP emits a strong green fluorescence (516 nm) that changes irreversibly to red (581 nm) when irradiated with UV-light of 390 nm. This modification occurs due to a break in the peptide backbone next to the chromophore. This mechanism allows for localized tagging of the protein and makes EosFP an appropriate tool for tracking protein movement within living cells. Formation of the red chromophore involves cleaving the peptide backbone but includes almost no other changes in the protein structure.
According to single-molecule fluorescence spectroscopy, EosFP is tetrameric, and exhibits strong Forster resonance coupling within individual fluorophores. Like other fluorescent proteins, Eos can be used to report diverse signals in cells, tissues and organs without disturbing complex biological machinery. While the use of fluorescent proteins was once limited to the green fluorescent protein (GFP), in recent years many other fluorescent proteins have been cloned. Unlike GFPs, which are derived from the luminescent jellyfish Aequorea victoria, fluorescent proteins derived from anthozoa, including Eos, emit fluorescence in the red spectral range. The novel property of photoinduced green-to-red conversion in Eos is useful because it allows for localized tracking of proteins in living cells. EosFP is unique because it has a large separation in the wavelengths it can emit which allows for easy identification of peak colours. All green-to-red photoinducible fluorescent proteins, including Eos, contain a chromophoric unit derived from the tripeptide his-tyr-gly. This green-to-red conversion is completed by light rather than chemical oxidation such as in other FPs. | 1 | Applied and Interdisciplinary Chemistry |
Compared to ketones and aldehydes, esters are relatively resistant to reduction. The introduction of catalytic hydrogenation in the early part of the 20th century was a breakthrough; esters of fatty acids are hydrogenated to fatty alcohols.
A typical catalyst is copper chromite. Prior to the development of catalytic hydrogenation, esters were reduced on a large scale using the Bouveault–Blanc reduction. This method, which is largely obsolete, uses sodium in the presence of proton sources.
Especially for fine chemical syntheses, lithium aluminium hydride is used to reduce esters to two primary alcohols. The related reagent sodium borohydride is slow in this reaction. DIBAH reduces esters to aldehydes.
Direct reduction to give the corresponding ether is difficult as the intermediate hemiacetal tends to decompose to give an alcohol and an aldehyde (which is rapidly reduced to give a second alcohol). The reaction can be achieved using triethylsilane with a variety of Lewis acids. | 0 | Theoretical and Fundamental Chemistry |
Bilirubin is created by the activity of biliverdin reductase on biliverdin, a green tetrapyrrolic bile pigment that is also a product of heme catabolism. Bilirubin, when oxidized, reverts to become biliverdin once again. This cycle, in addition to the demonstration of the potent antioxidant activity of bilirubin, has led to the hypothesis that bilirubins main physiologic role is as a cellular antioxidant. Consistent with this, animal studies suggest that eliminating bilirubin results in endogenous oxidative stress. Bilirubins antioxidant activity may be particularly important in the brain, where it prevents excitotoxicity and neuronal death by scavenging superoxide during N-methyl-D-aspartic acid neurotransmission. | 1 | Applied and Interdisciplinary Chemistry |
The protein encoded by this gene mediates transcriptional control by interaction with the Krüppel-associated box repression domain found in many transcription factors. The protein localizes to the nucleus and is thought to associate with specific chromatin regions. The protein is a member of the tripartite motif family. This tripartite motif includes three zinc-binding domains, a RING, a B-box type 1 and a B-box type 2, and a coiled-coil region.
KAP1 is a ubiquitously expressed protein involved in many critical functions including: transcriptional regulation, cellular differentiation and proliferation, DNA damage repair, viral suppression, and apoptosis. Its functionality is dependent upon post-translational modifications. Sumoylated TRIM28 can assemble epigenetic machinery for gene silencing, while phosphorylated TRIM28 is involved in DNA repair. | 1 | Applied and Interdisciplinary Chemistry |
Fermentation does not require oxygen. If oxygen is present, some species of yeast (e.g., Kluyveromyces lactis or Kluyveromyces lipolytica) will oxidize pyruvate completely to carbon dioxide and water in a process called cellular respiration, hence these species of yeast will produce ethanol only in an anaerobic environment (not cellular respiration). This phenomenon is known as the Pasteur effect.
However, many yeasts such as the commonly used bakers yeast Saccharomyces cerevisiae or fission yeast Schizosaccharomyces pombe' under certain conditions, ferment rather than respire even in the presence of oxygen. In wine making this is known as the counter-Pasteur effect. These yeasts will produce ethanol even under aerobic conditions, if they are provided with the right kind of nutrition. During batch fermentation, the rate of ethanol production per milligram of cell protein is maximal for a brief period early in this process and declines progressively as ethanol accumulates in the surrounding broth. Studies demonstrate that the removal of this accumulated ethanol does not immediately restore fermentative activity, and they provide evidence that the decline in metabolic rate is due to physiological changes (including possible ethanol damage) rather than to the presence of ethanol. Several potential causes for the decline in fermentative activity have been investigated. Viability remained at or above 90%, internal pH remained near neutrality, and the specific activities of the glycolytic and alcohologenic enzymes (measured in vitro) remained high throughout batch fermentation. None of these factors appears to be causally related to the fall in fermentative activity during batch fermentation. | 1 | Applied and Interdisciplinary Chemistry |
The use of plants to remove contaminants from the environment or to render them less harmful is called phytoremediation. In the case of radionuclides, it is a viable technology when decontamination times are long and waste are scattered at low concentrations.
Some plant species are able to transform the state of radioisotopes (without suffering toxicity) concentrating them in different parts of their structure, making them rush through the roots, making them volatile or stabilizing them on the ground. As in bacteria, plant genetic engineering procedures and biostimulation —called phytostimulation— have improved and accelerate these processes, particularly with regard to fast-growing plants. The use of Agrobacterium rhizogenes, for example, is quite widespread and significantly increases radionuclide uptake by the roots. | 1 | Applied and Interdisciplinary Chemistry |
A thioamide (rarely, thionamide, but also known as thiourylenes) is a functional group with the general structure , where are any groups (typically organyl groups or hydrogen). Analogous to amides, thioamides exhibit greater multiple bond character along the C-N bond, resulting in a larger rotational barrier. | 0 | Theoretical and Fundamental Chemistry |
Lake Chichoj is located near the city of San Cristóbal Verapaz, in the department of Alta Verapaz, in Guatemala. It is long, wide, with an area of , an average water volume of [], and a maximum depth of . | 1 | Applied and Interdisciplinary Chemistry |
Photochromic molecules can belong to various classes: triarylmethanes, stilbenes, azastilbenes, nitrones, fulgides, spiropyrans, naphthopyrans, spiro-oxazines, quinones and others. | 0 | Theoretical and Fundamental Chemistry |
There are several ways to test defoamers.
The easiest is looking at the surface foam. All that is needed is a system for generating foam. This might be done with a round pumping system with a nozzle and a cylinder or an air injection system into a cylinder. The cylinder is fitted with a scale to measure the foam height. This equipment may have a heater to control the temperature.
Entrained air can be tested with similar equipment that has a density meter that can record changes of the liquid density over time.
Drainage can be tested with a filter system for measuring the time to drain a liquid through the filter. The filter might be pressurized or have a vacuum. | 0 | Theoretical and Fundamental Chemistry |
Nucleation lays the foundation for the nanoparticle synthesis. Initial nuclei play a vital role on the size and shape of the nanoparticles that will ultimately form by acting as templating nuclei for the nanoparticle itself. Long-term stability is also determined by the initial nucleation procedures. Homogeneous nucleation occurs when nuclei form uniformly throughout the parent phase and is less common. Heterogeneous nucleation, however, forms on areas such as container surfaces, impurities, and other defects. Crystals may form simultaneously if nucleation is fast, creating a more monodisperse product. However, slow nucleation rates can cause formation of a polydisperse population of crystals with various sizes. Controlling nucleation allows for the control of size, dispersity, and phase of nanoparticles.
The process of nucleation and growth within nanoparticles can be described by nucleation, Ostwald ripening or the two-step mechanism-autocatalysis model. | 0 | Theoretical and Fundamental Chemistry |
Single colour reflectometry (SCORE), formerly known as imaging Reflectometric Interferometry (iRIf) and 1-lambda Reflectometry, is a physical method based on interference of monochromatic light at thin films, which is used to investigate (bio-)molecular interactions. The obtained binding curves using SCORE provide detailed information on kinetics and thermodynamics of the observed interaction(s) as well as on concentrations of the used analytes. These data can be relevant for pharmaceutical screening and drug design, biosensors and other biomedical applications, diagnostics, and cell-based assays. | 0 | Theoretical and Fundamental Chemistry |
In the Gladstone–Dale relation, , the index of refraction (n) or the density (ρ in g/cm) of miscible liquids that are mixed in mass fraction (m) can be calculated from characteristic optical constants (the molar refractivity k in cm/g) of pure molecular end-members. For example, for any mass (m) of ethanol added to a mass of water, the alcohol content is determined by measuring density or index of refraction (Brix refractometer). Mass (m) per unit volume (V) is the density m/V. Mass is conserved on mixing, but the volume of 1 cm of ethanol mixed with 1 cm of water is reduced to less than 2 cm due to the formation of ethanol-water bonds. The plot of volume or density versus molecular fraction of ethanol in water is a quadratic curve. However, the plot of index of refraction versus molecular fraction of ethanol in water is linear, and the weight fraction equals the fractional density
In the 1900s, the Gladstone–Dale relation was applied to glass, synthetic crystals and minerals. Average values for the refractivity of oxides such as MgO or SiO give good to excellent agreement between the calculated and measured average indices of refraction of minerals. However, specific values of refractivity are required to deal with different structure-types, and the relation required modification to deal with structural polymorphs and the birefringence of anisotropic crystal structures.
In recent optical crystallography, Gladstone–Dale constants for the refractivity of ions were related to the inter-ionic distances and angles of the crystal structure. The ionic refractivity depends on 1/d, where d is the inter-ionic distance, indicating that a particle-like photon refracts locally due to the electrostatic Coulomb force between ions. | 1 | Applied and Interdisciplinary Chemistry |
Hess's law states that enthalpy changes are additive. Thus the value of the standard enthalpy of reaction can be calculated from standard enthalpies of formation of products and reactants as follows:
Here, the first sum is over all products and the second over all reactants, and are the stoichiometric coefficients of products and reactants respectively, and are the standard enthalpies of formation of products and reactants respectively, and the </sup> superscript indicates standard state values. This may be considered as the sum of two (real or fictitious) reactions:
:Reactants → Elements (in their standard states)
and Elements → Products <br> | 0 | Theoretical and Fundamental Chemistry |
The reagent is prepared from trimethylsilyl chloride and bromotrifluoromethane in the presence of a phosphorus(III) reagent that serves as a halogen acceptor. | 0 | Theoretical and Fundamental Chemistry |
In 1896, Beijerinck first noted an incompatibility in solutions of agar, a water-soluble polymer, with soluble starch or gelatine. Upon mixing, they separated into two immiscible phases.
Subsequent investigation led to the determination of many other aqueous biphasic systems, of which the polyethylene glycol (PEG) - dextran system is the most extensively studied. Other systems that form aqueous biphases are: PEG - sodium carbonate or PEG and phosphates, citrates or sulfates. Aqueous biphasic systems are used during downstream processing mainly in biotechnological and chemical industries. | 0 | Theoretical and Fundamental Chemistry |
Proceeding in a similar way but taking the derivative with respect to we get a similar result for molar enthalpies:
Remembering that we get:
which in turn means that and that the enthalpy of the mix is equal to the sum of its component enthalpies.
Since and , similarly
It is also easily verifiable that | 0 | Theoretical and Fundamental Chemistry |
1,4-Butanedithiol is an organosulfur compound with the formula . It is a malodorous, colorless liquid that is highly soluble in organic solvents. The compound has found applications in biodegradable polymers. | 0 | Theoretical and Fundamental Chemistry |
Aside from the KIX domain, CBP and P300 contain many other protein binding domains that should not be confused (numbers are aa numberings):
* CH1/TAZ1 domain, CBP[347–433], P300[323-423]
* KIX domain, CBP[587–666], P300[566–645]
* Bromodomain, CBP[1103–1175], P300[1067–1139]
* CH2 domain (), CBP[1191–1317], P300[1155-1280].
* HAT domain, CBP[1323–1700], P300[1287–1663]
* CH3/ZZ domain, CBP[1701-1744], P300[1664-1707]
* CH3/TAZ2 domain, CBP[1765–1846], P300[1728-1809]
* IRF-3 binding (i-BiD), nuclear receptor coactivator binding (NCBD), or SRC1 interaction domain (SID; ), CBP[2020-2113], P300[1992-2098].
All three CH (cysteine/histidine-rich) domains are zinc fingers. | 1 | Applied and Interdisciplinary Chemistry |
Basic oxygen steelmaking is a primary steelmaking process for converting molten pig iron into steel by blowing oxygen through a lance over the molten pig iron inside the converter. Exothermic heat is generated by the oxidation reactions during blowing.
The basic oxygen steel-making process is as follows:
# Molten pig iron (sometimes referred to as "hot metal") from a blast furnace is poured into a large refractory-lined container called a ladle.
# The metal in the ladle is sent directly for basic oxygen steelmaking or to a pretreatment stage where sulfur, silicon, and phosphorus are removed before charging the hot metal into the converter. In external desulfurizing pretreatment, a lance is lowered into the molten iron in the ladle and several hundred kilograms of powdered magnesium are added and the sulfur impurities are reduced to magnesium sulfide in a violent exothermic reaction. The sulfide is then raked off. Similar pretreatments are possible for external desiliconisation and external dephosphorisation using mill scale (iron oxide) and lime as fluxes. The decision to pretreat depends on the quality of the hot metal and the required final quality of the steel.
# Filling the furnace with the ingredients is called charging. The BOS process is autogenous, i.e. the required thermal energy is produced during the oxidation process. Maintaining the proper charge balance, the ratio of hot metal from melt to cold scrap is important. The BOS vessel can be tilted up to 360° and is tilted towards the deslagging side for charging scrap and hot metal. The BOS vessel is charged with steel or iron scrap (25–30%), if required. Molten iron from the ladle is added as required for the charge balance. A typical chemistry of hotmetal charged into the BOS vessel is: 4% C, 0.2–0.8% Si, 0.08%–0.18% P, and 0.01–0.04% S, all of which can be oxidised by the supplied oxygen except sulfur (which requires reducing conditions).
# The vessel is then set upright and a water-cooled, copper tipped lance with 3–7 nozzles is lowered into it to within a few feet of the surface of the bath and high-purity oxygen at a pressure of is introduced at supersonic speed. The lance "blows" 99% pure oxygen over the hot metal, igniting the carbon dissolved in the steel, to form carbon monoxide and carbon dioxide, causing the temperature to rise to about 1700 °C. This melts the scrap, lowers the carbon content of the molten iron and helps remove unwanted chemical elements. It is this use of pure oxygen (instead of air) that improves upon the Bessemer process, as the nitrogen (an undesirable element) and other gases in air do not react with the charge, and decrease the efficiency of the furnace.
# Fluxes (burnt lime or dolomite) are fed into the vessel to form slag, to maintain basicity of the slag – the ratio of calcium oxide to silicon oxide – at a level to minimise refractory wear and absorb impurities during the steelmaking process. During "blowing", churning of metal and fluxes in the vessel forms an emulsion that facilitates the refining process. Near the end of the blowing cycle, which takes about 20 minutes, the temperature is measured and samples are taken. A typical chemistry of the blown metal is 0.3–0.9% C, 0.05–0.1% Mn, 0.001–0.003% Si, 0.01–0.03% S and 0.005–0.03% P.
# The BOS vessel is tilted towards the slagging side and the steel is poured through a tap hole into a steel ladle with basic refractory lining. This process is called tapping the steel. The steel is further refined in the ladle furnace, by adding alloying materials to impart special properties required by the customer. Sometimes argon or nitrogen is bubbled into the ladle to make the alloys mix correctly.
# After the steel is poured off from the BOS vessel, the slag is poured into the slag pots through the BOS vessel mouth and dumped. | 1 | Applied and Interdisciplinary Chemistry |
Superhydrophobic surfaces can be created in a number of different ways including plasma or ion etching, crystal growth on a material surface, and nanolithography to name a few. All of these processes create nano-topographical features which imbue a surface with superhydrophobicity. The ultimate goal in developing superhydrophobic surfaces is to recreate the self-cleaning properties of the Lotus Leaf that has the inherent ability to repel all water in nature. The basis for superhydrophobic self-cleaning is the ability of these surfaces to prevent water from spreading out when in contact with the surface. This is reflected in a water contact angle nearing 180 degrees. Superhydrophobic self-cleaning surfaces also have low sliding angles which allows for water that is collected on the surface to easily be removed, commonly by gravity. While superhydrophobic surfaces are great for removing any water-based debris, these surfaces likely will not be able to clean away other types of fouling matter such as oil. | 0 | Theoretical and Fundamental Chemistry |
Glycorandomization is used in the pharmaceutical industry and academic community to alter glycosylation patterns of sugar-containing natural products or to append sugars to drugs/drug leads. It provides a fast way to investigate the effect of subtle sugar modification on the pharmacological properties of the natural products analogues, thus, affording a new approach to drug discovery. | 0 | Theoretical and Fundamental Chemistry |
Glycosylamines are a class of biochemical compounds consisting of a glycosyl group attached to an amino group, -NR. They are also known as N-glycosides, as they are a type of glycoside. Glycosyl groups can be derived from carbohydrates. The glycosyl group and amino group are connected with a β-N-glycosidic bond, forming a cyclic hemiaminal ether bond (α-aminoether).
Examples include nucleosides such as adenosine. | 1 | Applied and Interdisciplinary Chemistry |
Concentrated sulfuric acid can perform a dehydration reaction with table sugar. After mixing, the color changes from white to brownish and eventually to black. The expansion of the mixture is the result of vaporization of water and CO inside the container. The gases inflate the mixture to form a snake-like shape, and give off a burned sugar smell. The granularity of the sugar can greatly affect the reaction: powdered sugar reacts very quickly but sugar cubes take longer to react.
When sucrose is dehydrated, heat is given out to the surroundings in an exothermic reaction, while graphite and liquid water are produced by the decomposition of the sugar:
:CHO + HSO + 1/2 O → 11 C + CO + 12 HO + SO
As the acid dehydrates the sucrose, the water produced will dilute the sulfuric acid, giving out energy in the form of heat.
:CHO → 12 C + 11 HO | 1 | Applied and Interdisciplinary Chemistry |
The rapamycin analog temsirolimus (CCI-779) is also a noncytotoxic agent which delays tumor proliferation.
Temsirolimus is a prodrug of rapamycin. It is approved by the U.S. Food and Drug Administration (FDA) and the European Medicines Agency (EMA), for the treatment of renal cell carcinoma (RCC). Temsirolimus has higher water solubility than rapamycin and is therefore administered by intravenous injection. It was approved on May 30, 2007, by FDA for the treatment of advanced RCC.
Temsirolimus has also been used in a Phase I clinical trial in conjunction with neratinib, a small-molecule irreversible pan-HER tyrosine kinase inhibitor. This study enrolled patients being treated for HER2-amplified breast cancer, HER2-mutant non-small-cell lung cancer, and other advanced solid tumors. While common toxicities included nausea, stomatitis, and anemia; responses were noted. | 1 | Applied and Interdisciplinary Chemistry |
In brief, corrosion is a chemical reaction occurring by an electrochemical mechanism (a redox reaction). During corrosion of iron or steel there are two reactions, oxidation (equation ), where electrons leave the metal (and the metal dissolves, i.e. actual loss of metal results) and reduction, where the electrons are used to convert oxygen and water to hydroxide ions (equation ):
In most environments, the hydroxide ions and ferrous ions combine to form ferrous hydroxide, which eventually becomes the familiar brown rust:
As corrosion takes place, oxidation and reduction reactions occur and electrochemical cells are formed on the surface of the metal so that some areas will become anodic (oxidation) and some cathodic (reduction). Electrons flow from the anodic areas into the electrolyte as the metal corrodes. Conversely, as electrons flow from the electrolyte to the cathodic areas, the rate of corrosion is reduced. (The flow of electrons is in the opposite direction of the flow of electric current.)
As the metal continues to corrode, the local potentials on the surface of the metal will change and the anodic and cathodic areas will change and move. As a result, in ferrous metals, a general covering of rust is formed over the whole surface, which will eventually consume all the metal. This is rather a simplified view of the corrosion process, because it can occur in several different forms.
Prevention of corrosion by cathodic protection (CP) works by introducing another metal (the galvanic anode) with a much more anodic surface, so that all the current will flow from the introduced anode and the metal to be protected becomes cathodic in comparison to the anode. This effectively stops the oxidation reactions on the metal surface by transferring them to the galvanic anode, which will be sacrificed in favour of the structure under protection. More simply put, this takes advantage of the relatively low stability of magnesium, aluminum or zinc metals; they dissolve instead of iron because their bonding is weaker compared to iron, which is bonded strongly via its partially filled d-orbitals.
For this protection to work there must be an electron pathway between the anode and the metal to be protected (e.g., a wire or direct contact) and an ion pathway between both the oxidizing agent (e.g., oxygen and water or moist soil) and the anode, and the oxidizing agent and the metal to be protected, thus forming a closed circuit; therefore simply bolting a piece of active metal such as zinc to a less active metal, such as mild steel, in air (a poor ionic conductor) will not furnish any protection. | 0 | Theoretical and Fundamental Chemistry |
Calmagite is a complexometric indicator used in analytical chemistry to identify the presence of metal ions in solution. As with other metal ion indicators calmagite will change color when it is bound to an ion. Calmagite will be wine red when it is bound to a metal ion and may be blue, red, or orange when it is not bound to a metal ion. Calmagite is often used in conjunction with EDTA, a stronger metal binding agent. This chemical is also used in the quantitation of magnesium in the clinical laboratory. | 0 | Theoretical and Fundamental Chemistry |
In recent years a mammalian two hybrid (M2H) system has been designed to study mammalian protein-protein interactions in a cellular environment that closely mimics the native protein environment. Transiently transfected mammalian cells are used in this system to find protein-protein interactions.
Using a mammalian cell line to study mammalian protein-protein interactions gives the advantage of working in a more native context.
The post-translational modifications, phosphorylation, acylation and glycosylation are similar. The intracellular localization of the proteins is also more correct compared to using a yeast two hybrid system.
It is also possible with the mammalian two-hybrid system to study signal inputs.
Another big advantage is that results can be obtained within 48 hours after transfection. | 1 | Applied and Interdisciplinary Chemistry |
In humans, there exist three paraologous ANT isoforms:
* SLC25A4 – found primarily in heart and skeletal muscle
* SLC25A5 – primarily expressed in fibroblasts
* SLC25A6 – primarily express in liver | 1 | Applied and Interdisciplinary Chemistry |
van der Waals force is actually the total name of dipole-dipole force, dipole-induced dipole force and dispersion forces, in which dispersion forces are the most important part because they are always present.
Assume that the pair potential between two atoms or small molecules is purely attractive and of the form w = −C/r, where C is a constant for interaction energy, decided by the molecule's property and n = 6 for van der Waals attraction. With another assumption of additivity, the net interaction energy between a molecule and planar surface made up of like molecules will be the sum of the interaction energy between the molecule and every molecule in the surface body. So the net interaction energy for a molecule at a distance D away from the surface will therefore be
where
* is the interaction energy between the molecule and the surface,
* is the number density of the surface,
* is the axis perpendicular to the surface and passesding across the molecule, with at the point where the molecule is, and at the surface,
* is the axis perpendicular to the axis, with at the intersection.
Then the interaction energy of a large sphere of radius R and a flat surface can be calculated as
where
* W(D) is the interaction energy between the sphere and the surface,
* is the number density of the sphere.
For convenience, Hamaker constant A is given as
and the equation becomes
With a similar method and according to Derjaguin approximation, the van der Waals interaction energy between particles with different shapes can be calculated, such as energy between
* two spheres:
* sphere and surface:
* two surfaces: per unit area. | 0 | Theoretical and Fundamental Chemistry |
MP Materials is 51.8%-owned by US hedge funds JHL Capital Group (and its CEO James Litinsky) and QVT Financial LP, while Shenghe Resources Holding Co. Ltd., a partially state-owned enterprise of the Government of China, holds an 8.0% stake. Apart from institutions, the public owns 18%. | 1 | Applied and Interdisciplinary Chemistry |
Consider next the necessary requirements for the appearance of lateral growth. It is evident that the lateral growth mechanism will be found when any area in the surface can reach a metastable equilibrium in the presence of a driving force. It will then tend to remain in such an equilibrium configuration until the passage of a step. Afterward, the configuration will be identical except that each part of the step will have advanced by the step height. If the surface cannot reach equilibrium in the presence of a driving force, then it will continue to advance without waiting for the lateral motion of steps.
Thus, Cahn concluded that the distinguishing feature is the ability of the surface to reach an equilibrium state in the presence of the driving force. He also concluded that for every surface or interface in a crystalline medium, there exists a critical driving force, which, if exceeded, will enable the surface or interface to advance normal to itself, and, if not exceeded, will require the lateral growth mechanism.
Thus, for sufficiently large driving forces, the interface can move uniformly without the benefit of either a heterogeneous nucleation or screw dislocation mechanism. What constitutes a sufficiently large driving force depends upon the diffuseness of the interface, so that for extremely diffuse interfaces, this critical driving force will be so small that any measurable driving force will exceed it. Alternatively, for sharp interfaces, the critical driving force will be very large, and most growth will occur by the lateral step mechanism.
Note that in a typical solidification or crystallization process, the thermodynamic driving force is dictated by the degree of supercooling. | 0 | Theoretical and Fundamental Chemistry |
One example of a binary chemical weapon is the United States Army M687. In the M687, methylphosphonyl difluoride (military name: DF, a Schedule 1 chemical) and a mixture of two agents are held in chambers within the munition, separated by a partition. When the weapon is fired, acceleration causes the partition to break, and the precursors are mixed by the rotation of the munition in flight, producing sarin nerve agent.
The Soviet Union and later Russian Federation experimented with binary munitions capable of mixing and distributing two agents that would work together in worsening the weapon's effects, an example of which would be the combination of nerve agents with blister agents.
The director of a non-proliferation research program of the Middlebury Institute of International Studies at Monterey has stated that the assassination of Kim Jong-nam due to poisoning with VX was likely carried out with a binary version of the agent, since VX fumes would otherwise have killed the suspected attackers. | 1 | Applied and Interdisciplinary Chemistry |
SETAC promotes environmental sciences through conducting meetings, workshops, and symposia; bestowing awards recognizing for excellence; promoting education in the field by organizing training courses and supporting students; and through its publication program. It holds meetings and events around the world. It produces two scientific journals; Environmental Toxicology and Chemistry (ET&C), which it has produced since 1982, originally yearly and then monthly from 1986; and Integrated Environmental Assessment and Management (IEAM). It also produces online books and easy to read Technical Issue Papers and Science Briefs, which are publicly available. | 1 | Applied and Interdisciplinary Chemistry |
RNA-Seq of human pathogens has become an established method for quantifying gene expression changes, identifying novel virulence factors, predicting antibiotic resistance, and unveiling host-pathogen immune interactions. A primary aim of this technology is to develop optimised infection control measures and targeted individualised treatment.
Transcriptomic analysis has predominantly focused on either the host or the pathogen. Dual RNA-Seq has been applied to simultaneously profile RNA expression in both the pathogen and host throughout the infection process. This technique enables the study of the dynamic response and interspecies gene regulatory networks in both interaction partners from initial contact through to invasion and the final persistence of the pathogen or clearance by the host immune system. | 1 | Applied and Interdisciplinary Chemistry |
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