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Recently thiourea has been investigated for its multiple desirable properties as a fertilizer especially under conditions of environmental stress. It may be applied in various capacities, such as a seed pretreatment (for priming), foliar spray or medium supplementation. | 0 | Theoretical and Fundamental Chemistry |
Observations relating to CAM were first made by de Saussure in 1804 in his Recherches Chimiques sur la Végétation. Benjamin Heyne in 1812 noted that Bryophyllum leaves in India were acidic in the morning and tasteless by afternoon. These observations were studied further and refined by Aubert, E. in 1892 in his Recherches physiologiques sur les plantes grasses and expounded upon by Richards, H. M. 1915 in Acidity and Gas Interchange in Cacti, Carnegie Institution. The term CAM may have been coined by Ranson and Thomas in 1940, but they were not the first to discover this cycle. It was observed by the botanists Ranson and Thomas, in the succulent family Crassulaceae (which includes jade plants and Sedum). The name "Crassulacean acid metabolism" refers to acid metabolism in Crassulaceae, and not the metabolism of "crassulacean acid"; there is no chemical by that name. | 0 | Theoretical and Fundamental Chemistry |
Leakage of Nr (reactive nitrogen) from human activities can cause nitrate accumulation in the natural water environment, which can create harmful impacts on human health. Excessive use of N-fertilizer in agriculture has been one of the major sources of nitrate pollution in groundwater and surface water. Due to its high solubility and low retention by soil, nitrate can easily escape from the subsoil layer to the groundwater, causing nitrate pollution. Some other non-point sources for nitrate pollution in groundwater are originated from livestock feeding, animal and human contamination and municipal and industrial waste. Since groundwater often serves as the primary domestic water supply, nitrate pollution can be extended from groundwater to surface and drinking water in the process of potable water production, especially for small community water supplies, where poorly regulated and unsanitary waters are used.
The WHO standard for drinking water is 50 mg L for short-term exposure, and for 3 mg L chronic effects. Once it enters the human body, nitrate can react with organic compounds through nitrosation reactions in the stomach to form nitrosamines and nitrosamides, which are involved in some types of cancers (e.g., oral cancer and gastric cancer). | 1 | Applied and Interdisciplinary Chemistry |
In 1858 Hermann von Helmholtz published his seminal paper "Über Integrale der hydrodynamischen Gleichungen, welche den Wirbelbewegungen entsprechen," in Journal für die reine und angewandte Mathematik, vol. 55, pp. 25–55. So important was the paper that a few years later P. G. Tait published an English translation, "On integrals of the hydrodynamical equations which express vortex motion", in Philosophical Magazine, vol. 33, pp. 485–512 (1867). In his paper Helmholtz established his three "laws of vortex motion" in much the same way one finds them in any advanced textbook of fluid mechanics today. This work established the significance of vorticity to fluid mechanics and science in general.
For the next century or so vortex dynamics matured as a subfield of fluid mechanics, always commanding at least a major chapter in treatises on the subject. Thus, H. Lambs well known Hydrodynamics (6th ed., 1932) devotes a full chapter to vorticity and vortex dynamics as does G. K. Batchelors [https://archive.today/20130112165003/http://www.cambridge.org/uk/series/sSeries.asp?code=CML&srt=T Introduction to Fluid Dynamics] (1967). In due course entire treatises were devoted to vortex motion. H. Poincarés Théorie des Tourbillons (1893), [http://genealogy.math.ndsu.nodak.edu/html/id.phtml?id=80970 H. Villats] Leçons sur la Théorie des Tourbillons (1930), C. Truesdells The Kinematics of Vorticity (1954), and P. G. Saffmans [https://web.archive.org/web/20070314022441/http://www.cambridge.org/us/catalogue/email.asp?isbn=0521477395 Vortex Dynamics] (1992) may be mentioned. Early on individual sessions at scientific conferences were devoted to vortices, vortex motion, vortex dynamics and vortex flows. Later, entire meetings were devoted to the subject.
The range of applicability of Helmholtz's work grew to encompass atmospheric and oceanographic flows, to all branches of engineering and applied science and, ultimately, to superfluids (today including Bose–Einstein condensates). In modern fluid mechanics the role of vortex dynamics in explaining flow phenomena is firmly established. Well known vortices have acquired names and are regularly depicted in the popular media: hurricanes, tornadoes, waterspouts, aircraft trailing vortices (e.g., wingtip vortices), drainhole vortices (including the bathtub vortex), smoke rings, underwater bubble air rings, cavitation vortices behind ship propellers, and so on. In the technical literature a number of vortices that arise under special conditions also have names: the Kármán vortex street wake behind a bluff body, Taylor vortices between rotating cylinders, Görtler vortices in flow along a curved wall, etc. | 1 | Applied and Interdisciplinary Chemistry |
Scholars previously believed that sub-Saharan Africans either did not have a period of using copper until the nineteenth century (going from the Stone Age directly into the Iron Age), or that they started smelting iron and copper at the same time. Copper smelting is thought to have been practiced in Nubia, during the early Old Kingdom c. 2686–2181 BC.
The principal evidence for this claim is an Egyptian outpost established in Buhen (near today's Sudanese-Egyptian border) around 2600 BC to smelt copper ores from Nubia. Alongside this, a crucible furnace dating to 2300–1900 BC for bronze casting has been found at the temple precinct at Kerma (in present-day northern Sudan), however the source of the tin remains unknown. Over the next millennium Nubians developed great skill in working copper and other known metals.
Discoveries in the Agadez Region of Niger evidence signs of copper metallurgy as early as 2000 BC. This date pre-dates the use of iron by a thousand years. Copper metallurgy seems to have been an indigenous invention in this area, because there is no clear evidence of influences from Northern Africa, and the Saharan wet phase was coming to an end, hindering human interactions across the Saharan region. It appeared to not be fully developed copper metallurgy, which suggests it was not from external origins. The people used native copper at first, and experimented with different furnace styles in order to smelt the ore between 2500 and 1500 BC.
Copper metallurgy has been recorded at Akjoujt in western Mauritania. The Akjoujt site is later than Agadez, dating back to around 850 BC. There is evidence of mining between 850 and 300 BC. Radiocarbon dates from the Grotte aux Chauves-souris mine shows that the extraction and smelting of malachite goes back to the early fifth century BC. A number of copper artifacts—including arrow points, spearheads, chisels, awls and plano-convex axes as well as bracelets, bead and earrings—were found at Neolithic sites in the region.
Collecting dates from Tropical Africa has been extremely difficult. No dates are available for the copper mine in pre-colonial Nigeria, and the earliest dates available south of the equator are around 345 AD at Naviundu springs near Lubumbashi in the Democratic Republic of Congo (DRC). Kansanshi mine in Zambia and Kipushi mine in the DRC date to between the fifth and twelfth centuries. Sites further south have produced later dates, for example the Thakadu mines in Botswana date to between 1480 and 1680; other major mines in Botswana, Namibia, and South Africa remain undated. | 1 | Applied and Interdisciplinary Chemistry |
Pipelines are generally laid underground because temperature is less variable. Because pipelines are usually metal, this helps to reduce the expansion and shrinkage that can occur with weather changes. However, in some cases it is necessary to cross a valley or a river on a pipeline bridge. Pipelines for centralized heating systems are often laid on the ground or overhead. Pipelines for petroleum running through permafrost areas as Trans-Alaska-Pipeline are often run overhead in order to avoid melting the frozen ground by hot petroleum which would result in sinking the pipeline in the ground. | 1 | Applied and Interdisciplinary Chemistry |
Reducing the displacement of the craft, by eliminating excess weight, is the most straightforward way to reduce the wave making drag. Another way is to shape the hull so as to generate lift as it moves through the water. Semi-displacement hulls and planing hulls do this, and they are able to break through the hull speed barrier and transition into a realm where drag increases at a much lower rate. The disadvantage of this is that planing is only practical on smaller vessels, with high power-to-weight ratios, such as motorboats. It is not a practical solution for a large vessel such as a supertanker. | 1 | Applied and Interdisciplinary Chemistry |
For Raman spectra the molecules undergo transitions in which an incident photon is absorbed and another scattered photon is emitted. The general selection rule for such a transition to be allowed is that the molecular polarizability must be anisotropic, which means that it is not the same in all directions. Polarizability is a 3-dimensional tensor that can be represented as an ellipsoid. The polarizability ellipsoid of spherical top molecules is in fact spherical so those molecules show no rotational Raman spectrum. For all other molecules both Stokes and anti-Stokes lines can be observed and they have similar intensities due to the fact that many rotational states are thermally populated. The selection rule for linear molecules is ΔJ = 0, ±2. The reason for the values ±2 is that the polarizability returns to the same value twice during a rotation. The value ΔJ = 0 does not correspond to a molecular transition but rather to Rayleigh scattering in which the incident photon merely changes direction.
The selection rule for symmetric top molecules is
: ΔK = 0
: If K = 0, then ΔJ = ±2
: If K ≠ 0, then ΔJ = 0, ±1, ±2
Transitions with ΔJ = +1 are said to belong to the R series, whereas transitions with belong to an S series. Since Raman transitions involve two photons, it is possible for the molecular angular momentum to change by two units. | 0 | Theoretical and Fundamental Chemistry |
CRP concentrations between 2 and 10 mg/L are considered as metabolic inflammation: metabolic pathways that cause arteriosclerosis and type II diabetes mellitus | 1 | Applied and Interdisciplinary Chemistry |
The use of NHC-Pd-PEPPSI complexes in Negishi cross-coupling has resulted in high turnover numbers and turnover frequencies. Additionally, NHC-Pd complexes can be used to couple sp3 centers to sp3 centers in higher yield than their non-NHC Pd analogs. However, studies of Pd-NHC complexes and their utility in Negishi coupling are currently lacking despite these promising results. | 0 | Theoretical and Fundamental Chemistry |
The chemical reactions and mechanism in the blue bottle experiment rely on the oxidation of a sugar with the aid of air and a redox dye in a basic solution. Other variations of this reaction have been reported that use four families of redox dyes: thiazines, oxazines, azines, and indigo carmine have all been reported to work with glucose and caustic soda. | 1 | Applied and Interdisciplinary Chemistry |
Increase in the number of dislocations is a quantification of work hardening. Plastic deformation occurs as a consequence of work being done on a material; energy is added to the material. In addition, the energy is almost always applied fast enough and in large enough magnitude to not only move existing dislocations, but also to produce a great number of new dislocations by jarring or working the material sufficiently enough. New dislocations are generated in proximity to a Frank–Read source.
Yield strength is increased in a cold-worked material. Using lattice strain fields, it can be shown that an environment filled with dislocations will hinder the movement of any one dislocation. Because dislocation motion is hindered, plastic deformation cannot occur at normal stresses. Upon application of stresses just beyond the yield strength of the non-cold-worked material, a cold-worked material will continue to deform using the only mechanism available: elastic deformation, the regular scheme of stretching or compressing of electrical bonds (without dislocation motion) continues to occur, and the modulus of elasticity is unchanged. Eventually the stress is great enough to overcome the strain-field interactions and plastic deformation resumes.
However, ductility of a work-hardened material is decreased. Ductility is the extent to which a material can undergo plastic deformation, that is, it is how far a material can be plastically deformed before fracture. A cold-worked material is, in effect, a normal (brittle) material that has already been extended through part of its allowed plastic deformation. If dislocation motion and plastic deformation have been hindered enough by dislocation accumulation, and stretching of electronic bonds and elastic deformation have reached their limit, a third mode of deformation occurs: fracture. | 1 | Applied and Interdisciplinary Chemistry |
The HO radical is linked with the production of HO in molecular clouds. Studies of HO distribution in Taurus Molecular Cloud-1 (TMC-1) suggest that in dense gas, HO is mainly formed by dissociative recombination of HO. Dissociative recombination is the reaction in which a molecular ion recombines with an electron and dissociates into neutral fragments. Important formation mechanisms for HO are:
HO + e → HO + H (1a) Dissociative recombination
HO + e → HO + H + H (1b) Dissociative recombination
HCO + e → HO + CO (2a) Dissociative recombination
O + HCO → HO + CO (3a) Neutral-neutral
H + HO → HO + H + H (4a) Ion-molecular ion neutralization | 1 | Applied and Interdisciplinary Chemistry |
The longer tag sequence confers a higher specificity than the classical SAGE tag of 9–10 bp. The level of unique gene expression is represented by the count of transcripts present per million molecules, similar to SAGE output. A significant advantage is the larger library size compared with SAGE. An MPSS library typically holds 1 million signature tags, which is roughly 20 times the size of a SAGE library. Some of the disadvantages related to SAGE apply to MPSS as well, such as loss of certain transcripts due to lack of restriction enzyme recognition site and ambiguity in tag annotation. The high sensitivity and absolute gene expression certainly favors MPSS. However, the technology is only available through Lynxgen Therapeutics, Inc. (then Solexa Inc till 2006 and then Illumina). | 1 | Applied and Interdisciplinary Chemistry |
By far, the most prevalent bulk material for solar cells is crystalline silicon (c-Si), also known as "solar grade silicon". Bulk silicon is separated into multiple categories according to crystallinity and crystal size in the resulting ingot, ribbon or wafer. These cells are entirely based around the concept of a p–n junction. Solar cells made of c-Si are made from wafers between 160 and 240 micrometers thick. | 0 | Theoretical and Fundamental Chemistry |
Anti-depressants have been prescribed since the 1950s, and their prevalence has significantly increased since then. There are many classes of anti-depressant pharmaceuticals, such as selective serotonin reuptake inhibitors (SSRIs), monoamine oxidase inhibitors (MAOIs), and tricyclic anti-depressants. Many of these drugs, especially the SSRIs, function by blocking the metabolism or reuptake of neurotransmitters to treat depression and anxiety. Chronic exposure or overdose of these pharmaceuticals can lead to serotonin and CNS hyperexcitation, weight changes, and, in severe cases, suicide. | 1 | Applied and Interdisciplinary Chemistry |
Planktonic prokaryotes are further defined into two categories, free-living or particle associated. The two are separated by filtration. Particle-associated bacteria are often difficult to study because marine snow aggregates are often ranging in sizes from 0.2 to 200 μm, often rendering sampling efforts difficult. These aggregates are hotspots for microbial activity. Marine bacteria are the most abundant organisms in aggregates followed by cyanobacteria and then nanoflagellates. Aggregates can be enriched about one thousand times more than the surrounding seawater. Seasonal variability can also have an effect on microbial communities of marine snow aggregates with concentrations being the highest during the summer.
As illustrated in the diagram, phytoplankton fix carbon dioxide in the euphotic zone using solar energy and produce particulate organic carbon. The particulate organic carbon formed in the euphotic zone is processed by marine microorganisms (microbes), zooplankton and their consumers into organic aggregates (marine snow), which is then exported to the mesopelagic (200–1000 m depth) and bathypelagic zones by sinking and vertical migration by zooplankton and fish.
Export flux is defined as the sedimentation out of the surface layer (at approximately 100 m depth) and sequestration flux is the sedimentation out of the mesopelagic zone (at approximately 1000 m depth). A portion of the particulate organic carbon is respired back to CO in the oceanic water column at depth, mostly by heterotrophic microbes and zooplankton, thus maintaining a vertical gradient in concentration of dissolved inorganic carbon (DIC). This deep-ocean DIC returns to the atmosphere on millennial timescales through thermohaline circulation. Between 1% and 40% of the primary production is exported out of the euphotic zone, which attenuates exponentially towards the base of the mesopelagic zone and only about 1% of the surface production reaches the sea floor.
The largest component of biomass are marine protists (eukaryotic microorganisms). Marine snow aggregates collected from the bathypelagic zone were found to consist largely of fungi and labyrinthulomycetes. Smaller aggregates do not harbor as many eukaryotic organisms which is similar to what is found in the deep ocean. The bathypelagic aggregates mostly resembled those found in the surface ocean. It implies higher rates of remineralization in the bathypelagic zone.
Numerically, the largest component of marine snow are the prokaryotes that colonize the aggregates. Bacteria are largely responsible for the remineralisation and fragmentation of aggregates. Remineralization occurs typically below 200 m depth.
Microbial communities that form on the aggregates vary from the communities in the water column. The concentration of attached microbes are typically orders of magnitude larger than free-living microbes. Isolated bacterial cultures have up to 20 times more enzymatic activity within 2 hours of aggregate attachment. The dark ocean harbors around 65% of all pelagic Bacteria and Archaea.(Whitman et al., 1998)
It was previously thought that due to fragmentation, bacterial communities would shift as they travel down the water column. As seen in experiments, it now appears that the communities that form during aggregation remain associated with the aggregate and any community changes are due to grazing or fragmentation rather than new bacterial colony formation. | 0 | Theoretical and Fundamental Chemistry |
RdRps are highly conserved throughout viruses and are even related to telomerase, though the reason for this is an ongoing question as of 2009. The similarity has led to speculation that viral RdRps are ancestral to human telomerase.
The most famous example of RdRp is that of the polio virus. The viral genome is composed of RNA, which enters the cell through receptor-mediated endocytosis. From there, the RNA is able to act as a template for complementary RNA synthesis, immediately. The complementary strand is then, itself, able to act as a template for the production of new viral genomes that are further packaged and released from the cell ready to infect more host cells. The advantage of this method of replication is that there is no DNA stage; replication is quick and easy. The disadvantage is that there is no back-up DNA copy.
Many RdRps are associated tightly with membranes and are, therefore, difficult to study. The best-known RdRps are polioviral 3Dpol, vesicular stomatitis virus L, and hepatitis C virus NS5B protein.
Many eukaryotes also have RdRps and these are involved in RNA interference: these amplify microRNAs and small temporal RNAs and produce double-stranded RNA using small interfering RNAs as primers. In fact these same RdRps that are used in the defense mechanisms can be usurped by RNA viruses for their benefit. Their evolutionary history has been reviewed. | 1 | Applied and Interdisciplinary Chemistry |
DSIF (DRB Sensitivity Inducing Factor) is a protein complex that can either negatively or positively affect transcription by RNA polymerase II (Pol II). It can interact with the negative elongation factor (NELF) to promote the stalling of Pol II at some genes, which is called promoter proximal pausing. The pause occurs soon after initiation, once 20-60 nucleotides have been transcribed. This stalling is relieved by positive transcription elongation factor b (P-TEFb) and Pol II enters productive elongation to resume synthesis till finish. In humans, DSIF is composed of hSPT4 and hSPT5. hSPT5 has a direct role in mRNA capping which occurs while the elongation is paused.
SPT5 is preserved in humans to bacteria. SPT4 and SPT5 in yeast are the homologs of hSPT4 and hSPT5. In bacteria, the homologous complex only contains NusG, a Spt5 homolog. Archaea have both proteins.
The complex locks the RNA polymerase (RNAP) clamp into a closed state to prevent the elongation complex (EC) from dissociating. The Spt5 NGN domain helps anneal the two strands of DNA upstream. The single KOW domain in bacteria and archaea anchors a ribosome to the RNAP. | 1 | Applied and Interdisciplinary Chemistry |
Supramolecular systems are rarely designed from first principles. Rather, chemists have a range of well-studied structural and functional building blocks that they are able to use to build up larger functional architectures. Many of these exist as whole families of similar units, from which the analog with the exact desired properties can be chosen. | 0 | Theoretical and Fundamental Chemistry |
A ChemFETs source and drain are constructed as for an ISFET, with the gate electrode separated from the source electrode by a solution. The gate electrodes interface with the solution is a semi-permeable membrane containing the receptors, and a gap to allow the substance under test to come in contact with the sensitive receptor moieties. A ChemFET's threshold voltage depends on the concentration gradient between the analyte in solution and the analyte in contact with its receptor-embedded semi-permeable barrier.
Often, ionophores are used to facilitate analyte ion mobility through the substrate to the receptor. For example, when targeting anions, quaternary ammonium salts (such as tetraoctylammonium bromide) are used to provide cationic nature to the membrane, facilitating anion mobility through the substrate to the receptor moieties. | 0 | Theoretical and Fundamental Chemistry |
Most synthetic channels are Ohmic in conductance, that is, the current passed (both individually and as an ensemble) is proportional to the potential across the membrane. Some rare channels, however, show current-voltage characteristics that is non-linear. Specifically, two different types of non-Ohmic conductance are known:
# a rectifying behaviour, where current passes depends on the sign of the applied potential, and
# a exponential potential dependence, where the current passed scales exponentially with the applied potential.
The former requires asymmetry with respect to the mid-plane of the lipid bilayer, and is realized often by introducing an overall molecular dipole. The latter, demonstrated in natural channels such as alamethicin, is rarely encountered in synthetic ion channels. They may be related to lipid ion channels, but to date their mechanism remains elusive. | 0 | Theoretical and Fundamental Chemistry |
# To date, microdialysis is the only in vivo sampling technique that can continuously monitor drug or metabolite concentrations in the extracellular fluid of virtually any tissue. Depending on the exact application, analyte concentrations can be monitored over several hours, days, or even weeks. Free, unbound extracellular tissue concentrations are in many cases of particular interest as they resemble pharmacologically active concentrations at or close to the site of action. Combination of microdialysis with modern imaging techniques, such positron emission tomography, further allow for determination of intracellular concentrations.
# Insertion of the probe in a precise location of the selected tissue further allows for evaluation of extracellular concentration gradients due to transporter activity or other factors, such as perfusion differences. It has, therefore, been suggested as the most appropriate technique to be used for tissue distribution studies.
# Exchange of analyte across the semipermeable membrane and constant replacement of the sampling fluid with fresh perfusate prevents drainage of fluid from the sampling site, which allows sampling without fluid loss. Microdialysis can consequently be used without disturbing the tissue conditions by local fluid loss or pressure artifacts, which can occur when using other techniques, such as microinjection or push-pull perfusion.
# The semipermeable membrane prevents cells, cellular debris, and proteins from entering into the dialysate. Due to the lack of protein in the dialysate, a sample clean-up prior to analysis is not needed and enzymatic degradation is not a concern. | 1 | Applied and Interdisciplinary Chemistry |
The following scientists of note worked in the Balliol-Trinity Laboratories:
* E. J. Bowen
* Sir John Conroy
* Sir Harold Hartley
* Sir Cyril Norman Hinshelwood (Nobel Prize winner)
* Henry Moseley | 0 | Theoretical and Fundamental Chemistry |
Atomic polarization is observed when the nucleus of the atom reorients in response to the electric field. This is a resonant process. Atomic polarization is intrinsic to the nature of the atom and is a consequence of an applied field. Electronic polarization refers to the electron density and is a consequence of an applied field. Atomic polarization is usually small compared to electronic polarization. | 0 | Theoretical and Fundamental Chemistry |
Roadsides receive substantial quantities of herbicides, both intentionally applied for their maintenance and due to herbicide drift from adjacent applications. This often kills off-target plants. | 1 | Applied and Interdisciplinary Chemistry |
Alkanes react with halogens by free radical halogenation. In this reaction a hydrogen atom is removed from the alkane, then replaced by a halogen atom by reaction with a diatomic halogen molecule. Free radical halogenation typically produces a mixture of compounds mono- or multihalogenated at various positions. | 0 | Theoretical and Fundamental Chemistry |
Kennedy was born on November 11, 1962, in Sault Ste. Marie, Michigan. He earned a Bachelor of Science degree in chemistry at the University of Florida in 1984 and a Ph.D. from the University of North Carolina-Chapel Hill (UNC) in 1988 while working under James Jorgenson. He was an NSF post-doctoral fellow at UNC from 1989-1991 with R. Mark Wightman. | 0 | Theoretical and Fundamental Chemistry |
Gymnochrome E is a cytotoxic phenanthroperylenequinone isolated from a deep-water crinoid called Holopus rangii. | 1 | Applied and Interdisciplinary Chemistry |
GC–MS is used for the analysis of unknown organic compound mixtures. One critical use of this technology is the use of GC–MS to determine the composition of bio-oils processed from raw biomass. GC–MS is also utilized in the identification of continuous phase component in a smart material, magnetorheological (MR) fluid. | 0 | Theoretical and Fundamental Chemistry |
Water quality refers to the chemical, physical, and biological characteristics of water based on the standards of its usage. It is most frequently used by reference to a set of standards against which compliance, generally achieved through treatment of the water, can be assessed. The most common standards used to monitor and assess water quality convey the health of ecosystems, safety of human contact, extent of water pollution and condition of drinking water. Water quality has a significant impact on water supply and oftentimes determines supply options. | 0 | Theoretical and Fundamental Chemistry |
A genomic library is a collection of overlapping DNA fragments that together make up the total genomic DNA of a single organism. The DNA is stored in a population of identical vectors, each containing a different insert of DNA. In order to construct a genomic library, the organism's DNA is extracted from cells and then digested with a restriction enzyme to cut the DNA into fragments of a specific size. The fragments are then inserted into the vector using DNA ligase. Next, the vector DNA can be taken up by a host organism - commonly a population of Escherichia coli or yeast - with each cell containing only one vector molecule. Using a host cell to carry the vector allows for easy amplification and retrieval of specific clones from the library for analysis.
There are several kinds of vectors available with various insert capacities. Generally, libraries made from organisms with larger genomes require vectors featuring larger inserts, thereby fewer vector molecules are needed to make the library. Researchers can choose a vector also considering the ideal insert size to find the desired number of clones necessary for full genome coverage.
Genomic libraries are commonly used for sequencing applications. They have played an important role in the whole genome sequencing of several organisms, including the human genome and several model organisms. | 1 | Applied and Interdisciplinary Chemistry |
A dystrophin-associated protein is a protein that helps to form the connection between intracellular dystrophin and the extracellular basal lamina.
Examples include sarcoglycan and dystroglycan. | 1 | Applied and Interdisciplinary Chemistry |
Classification of nerve damage was well-defined by Sir Herbert Seddon and Sunderland in a system that remains in use. The adjacent table details the forms (neurapraxia, axonotmesis and neurotmesis) and degrees of nerve injury that occur as a result of exposure to various temperatures.
Cryoneurolysis treatments that use nitrous oxide (boiling point of −88.5 °C) as the coolant fall in the range of an axonotmesis injury, or 2nd degree injury, according to the Sunderland classification system. Treatments of the nerve in this temperature range are reversible. Nerves treated in this temperature range experience a disruption of the axon, with Wallerian degeneration occurring distal to the site of injury. The axon and myelin sheath are affected, but all of the connective tissues (endoneurium, perineurium, and epineurium) remain intact. Following Wallerian degeneration, the axon regenerates along the original nerve path at a rate of approximately 1–2 mm per day.
Cryoneurolysis differs from cryoablation in that cryoablation treatments utilize liquid nitrogen (boiling point of −195.8 °C) as the coolant, and therefore, fall into the range of a neurotmesis injury, or 3rd degree injury according to the Sunderland classification. Treatments of the nerve in this temperature range are irreversible. Nerves treated in this temperature range experience a disruption of both the axon and the endoneurium connective tissue layer. | 1 | Applied and Interdisciplinary Chemistry |
Organic carbonates are not prepared from inorganic carbonate salts.
Two main routes to carbonate esters are practiced: the reaction of an alcohol (or phenol) with phosgene (phosgenation), and the reaction of an alcohol with carbon monoxide and an oxidizer (oxidative carbonylation). Other carbonate esters may subsequently be prepared by transesterification.
In principle carbonate esters can be prepared by direct condensation of methanol and carbon dioxide. The reaction is however thermodynamically unfavorable. A selective membrane can be used to separate the water from the reaction mixture and increase the yield. | 0 | Theoretical and Fundamental Chemistry |
Retinol (vitamin A) can be metabolized to retinoic acid which activates nuclear receptors such as the RAR to control differentiation and proliferation of many types of cells during development. | 1 | Applied and Interdisciplinary Chemistry |
Buffers in gel electrophoresis are used to provide ions that carry a current and to maintain the pH at a relatively constant value.
These buffers have plenty of ions in them, which is necessary for the passage of electricity through them. Something like distilled water or benzene contains few ions, which is not ideal for the use in electrophoresis. There are a number of buffers used for electrophoresis. The most common being, for nucleic acids Tris/Acetate/EDTA (TAE), Tris/Borate/EDTA (TBE). Many other buffers have been proposed, e.g. lithium borate, which is rarely used, based on Pubmed citations (LB), isoelectric histidine, pK matched goods buffers, etc.; in most cases the purported rationale is lower current (less heat) matched ion mobilities, which leads to longer buffer life. Borate is problematic; Borate can polymerize, or interact with cis diols such as those found in RNA. TAE has the lowest buffering capacity but provides the best resolution for larger DNA. This means a lower voltage and more time, but a better product. LB is relatively new and is ineffective in resolving fragments larger than 5 kbp; However, with its low conductivity, a much higher voltage could be used (up to 35 V/cm), which means a shorter analysis time for routine electrophoresis. As low as one base pair size difference could be resolved in 3% agarose gel with an extremely low conductivity medium (1 mM Lithium borate).
Most SDS-PAGE protein separations are performed using a "discontinuous" (or DISC) buffer system that significantly enhances the sharpness of the bands within the gel. During electrophoresis in a discontinuous gel system, an ion gradient is formed in the early stage of electrophoresis that causes all of the proteins to focus on a single sharp band in a process called isotachophoresis. Separation of the proteins by size is achieved in the lower, "resolving" region of the gel. The resolving gel typically has a much smaller pore size, which leads to a sieving effect that now determines the electrophoretic mobility of the proteins. | 1 | Applied and Interdisciplinary Chemistry |
Traugott Sandmeyer (15 September 1854 – 9 April 1922) was a Swiss chemist after whom the Sandmeyer reaction, which he discovered 1884, was named. | 1 | Applied and Interdisciplinary Chemistry |
A splice site mutation is a genetic mutation that inserts, deletes or changes a number of nucleotides in the specific site at which splicing takes place during the processing of precursor messenger RNA into mature messenger RNA. Splice site consensus sequences that drive exon recognition are located at the very termini of introns. The deletion of the splicing site results in one or more introns remaining in mature mRNA and may lead to the production of abnormal proteins. When a splice site mutation occurs, the mRNA transcript possesses information from these introns that normally should not be included. Introns are supposed to be removed, while the exons are expressed.
The mutation must occur at the specific site at which intron splicing occurs: within non-coding sites in a gene, directly next to the location of the exon. The mutation can be an insertion, deletion, frameshift, etc. The splicing process itself is controlled by the given sequences, known as splice-donor and splice-acceptor sequences, which surround each exon. Mutations in these sequences may lead to retention of large segments of intronic DNA by the mRNA, or to entire exons being spliced out of the mRNA. These changes could result in production of a nonfunctional protein. An intron is separated from its exon by means of the splice site. Acceptor-site and donor-site relating to the splice sites signal to the spliceosome where the actual cut should be made. These donor sites, or recognition sites, are essential in the processing of mRNA. The average vertebrate gene consists of multiple small exons (average size, 137 nucleotides) separated by introns that are considerably larger. | 1 | Applied and Interdisciplinary Chemistry |
The strength of a material is dependent on how easily dislocations in its crystal lattice can be propagated. These dislocations create stress fields within the material depending on their character. When solute atoms are introduced, local stress fields are formed that interact with those of the dislocations, impeding their motion and causing an increase in the yield stress of the material, which means an increase in strength of the material. This gain is a result of both lattice distortion and the modulus effect.
When solute and solvent atoms differ in size, local stress fields are created that can attract or repel dislocations in their vicinity. This is known as the size effect. By relieving tensile or compressive strain in the lattice, the solute size mismatch can put the dislocation in a lower energy state. In substitutional solid solutions, these stress fields are spherically symmetric, meaning they have no shear stress component. As such, substitutional solute atoms do not interact with the shear stress fields characteristic of screw dislocations. Conversely, in interstitial solid solutions, solute atoms cause a tetragonal distortion, generating a shear field that can interact with edge, screw, and mixed dislocations. The attraction or repulsion of the dislocation to the solute atom depends on whether the atom sits above or below the slip plane. For example, consider an edge dislocation encountering a smaller solute atom above its slip plane. In this case, the interaction energy is negative, resulting in attraction of the dislocation to the solute. This is due to the reduced dislocation energy by the compressed volume lying above the dislocation core. If the solute atom were positioned below the slip plane, the dislocation would be repelled by the solute. However, the overall interaction energy between an edge dislocation and a smaller solute is negative because the dislocation spends more time at sites with attractive energy. This is also true for solute atom with size greater than the solvent atom. Thus, the interaction energy dictated by the size effect is generally negative.
The elastic modulus of the solute atom can also determine the extent of strengthening. For a “soft” solute with elastic modulus lower than that of the solvent, the interaction energy due to modulus mismatch (U) is negative, which reinforce the size interaction energy (U). In contrast, U is positive for a “hard” solute, which results in lower total interaction energy than a soft atom. Even though the interaction force is negative (attractive) in both cases when the dislocation is approaching the solute. The maximum force (F) necessary to tear dislocation away from the lowest energy state (i.e. the solute atom) is greater for the soft solute than the hard one. As a result, a soft solute will strengthen a crystal more than a hard solute due to the synergistic strengthening by combining both size and modulus effects.
The elastic interaction effects (i.e. size and modulus effects) dominate solid-solution strengthening for most crystalline materials. However, other effects, including charge and stacking fault effects, may also play a role. For ionic solids where electrostatic interaction dictates bond strength, charge effect is also important. For example, addition of divalent ion to a monovalent material may strengthen the electrostatic interaction between the solute and the charged matrix atoms that comprise a dislocation. However, this strengthening is to a less extent than the elastic strengthening effects. For materials containing a higher density of stacking faults, solute atoms may interact with the stacking faults either attractively or repulsively. This lowers the stacking fault energy, leading to repulsion of the partial dislocations, which thus makes the material stronger.
Surface carburizing, or case hardening, is one example of solid solution strengthening in which the density of solute carbon atoms is increased close to the surface of the steel, resulting in a gradient of carbon atoms throughout the material. This provides superior mechanical properties to the surface of the steel without having to use a higher-cost material for the component. | 1 | Applied and Interdisciplinary Chemistry |
Conversion kits are available which will work in existing fittings containing switch start, mains frequency fluorescent lamp ballasts. The kits convert the fittings to use energy efficient, high frequency ballasts and accommodate the smaller diameter T5 lamp.
The magnetic ballast remains in place but it is bypassed, rendering it ineffective as a conductor. The new high-frequency ballast draws only 2 W, rather than the 6-10 W of the old ballast, increasing the efficiency of the system. Changing to this type of lamp without taking the ballast out of operation (rather than simply bypassing it) results in an increased power factor for the fitting. This increase in power is a result of the separate coils used in an electric ballast, as opposed to the single coil in a magnetic ballast, because it allows the electricity to flow more consistently.
There are tree main types of conversion kits:
* Lamp-end type – Kits which include a replacement starter and two separate components to fit over each end of the T5 lamp. The lamp is then slotted into the existing fitting.
* Baton type – One piece kits which slot into the existing fitting and into which the T5 lamp is placed.
* IP65 types – Waterproof | 1 | Applied and Interdisciplinary Chemistry |
In 1999, Brill published the sum of 39 years worth of results from his chemical investigations at Corning in two volumes of reference material with a third forthcoming (Brill 1999). Brill was reluctant to publish the data without any accompanying interpretation, but he felt that the most important factor was to quickly release the material into a wider sphere, made ‘readily accessible to the scientific community’ (1999, 8). Of Cornings 10,000 research artefacts, the master catalogue contains 6,400 samples, an abbreviated catalogue, or AbbCat, of which is presented in the two volumes (1999, 11). 19 geographical, typological or chronological categories of glass samples are recorded, spanning Brills various research projects and collaborations, from Egypt to the East (Brill 1999). It also records the results of oxygen isotope analyses, reminding us that Brill was ever one for the integration of different investigative methods. | 0 | Theoretical and Fundamental Chemistry |
The Glowing Plant project was the first crowdfunding campaign for a synthetic biology application. The project was started by the Sunnyvale-based hackerspace Biocurious as part of the DIYbio philosophy. According to the projects goals, funds were used to create a glowing Arabidopsis thaliana' plant using firefly luminescence genes. Long-term ambitions (never realized) included the development of glowing trees that can be used to replace street lights, reducing CO emissions by not requiring electricity. | 1 | Applied and Interdisciplinary Chemistry |
In terms of volume, most petroleum is converted into fuels for combustion engines. In terms of value, petroleum underpins the petrochemical industry, which includes many high value products such as pharmaceuticals and plastics. | 0 | Theoretical and Fundamental Chemistry |
The radiation hazards of uranium mining and milling were not appreciated in the early years, resulting in workers exposed to high levels of radiation. Inhalation of radon gas caused sharp increases in lung cancers among underground uranium miners employed in the 1940s and 1950s. | 0 | Theoretical and Fundamental Chemistry |
Recent advances in the identification of the tethers between the mitochondrial and ER membranes suggest that the scaffolding function of the molecular elements involved is secondary to other, non-structural functions. In yeast, ERMES, a multiprotein complex of interacting ER- and mitochondrial-resident membrane proteins, is required for lipid transfer at the MAM and exemplifies this principle. One of its components, for example, is also a constituent of the protein complex required for insertion of transmembrane beta-barrel proteins into the lipid bilayer. However, a homologue of the ERMES complex has not yet been identified in mammalian cells. Other proteins implicated in scaffolding likewise have functions independent of structural tethering at the MAM; for example, ER-resident and mitochondrial-resident mitofusins form heterocomplexes that regulate the number of inter-organelle contact sites, although mitofusins were first identified for their role in fission and fusion events between individual mitochondria. Glucose-related protein 75 (grp75) is another dual-function protein. In addition to the matrix pool of grp75, a portion serves as a chaperone that physically links the mitochondrial and ER Ca channels VDAC and IP3R for efficient Ca transmission at the MAM. Another potential tether is Sigma-1R, a non-opioid receptor whose stabilization of ER-resident IP3R may preserve communication at the MAM during the metabolic stress response. | 1 | Applied and Interdisciplinary Chemistry |
Although the self-cleaning phenomenon of the lotus was possibly known in Asia long before (reference to the lotus effect is found in the Bhagavad Gita), its mechanism was explained only in the early 1970s after the introduction of the scanning electron microscope. Studies were performed with leaves of Tropaeolum and lotus (Nelumbo).. Similar to lotus effect, a recent study has revealed honeycomb-like micro-structures on the taro leaf, which makes the leaf superhydrophobic. The measured contact angle on this leaf in this study is around 148 degrees. | 0 | Theoretical and Fundamental Chemistry |
While related general circulation models (GCMs) focus on simulating overall atmospheric dynamics (e.g. fluid and heat flows), a CTM instead focuses on the stocks and flows of one or more chemical species. Similarly, a CTM must solve only the continuity equation for its species of interest, a GCM must solve all the primitive equations for the atmosphere; but a CTM will be expected to accurately represent the entire cycle for the species of interest, including fluxes (e.g. advection), chemical production/loss, and deposition. That being said, the tendency, especially as the cost of computing declines over time, is for GCMs to incorporate CTMs for species of special interest to climate dynamics, especially shorter-lived species such as nitrogen oxides and volatile organic compounds; this allows feedbacks from the CTM to the GCM's radiation calculations, and also allows the meteorological fields forcing the CTM to be updated at higher time resolution than may be practical in studies with offline CTMs. | 1 | Applied and Interdisciplinary Chemistry |
Ionic bonding can result from a redox reaction when atoms of an element (usually metal), whose ionization energy is low, give some of their electrons to achieve a stable electron configuration. In doing so, cations are formed. An atom of another element (usually nonmetal) with greater electron affinity accepts one or more electrons to attain a stable electron configuration, and after accepting electrons an atom becomes an anion. Typically, the stable electron configuration is one of the noble gases for elements in the s-block and the p-block, and particular stable electron configurations for d-block and f-block elements. The electrostatic attraction between the anions and cations leads to the formation of a solid with a crystallographic lattice in which the ions are stacked in an alternating fashion. In such a lattice, it is usually not possible to distinguish discrete molecular units, so that the compounds formed are not molecular. However, the ions themselves can be complex and form molecular ions like the acetate anion or the ammonium cation.
For example, common table salt is sodium chloride. When sodium (Na) and chlorine (Cl) are combined, the sodium atoms each lose an electron, forming cations (Na), and the chlorine atoms each gain an electron to form anions (Cl). These ions are then attracted to each other in a 1:1 ratio to form sodium chloride (NaCl).
: Na + Cl → Na + Cl → NaCl
However, to maintain charge neutrality, strict ratios between anions and cations are observed so that ionic compounds, in general, obey the rules of stoichiometry despite not being molecular compounds. For compounds that are transitional to the alloys and possess mixed ionic and metallic bonding, this may not be the case anymore. Many sulfides, e.g., do form non-stoichiometric compounds.
Many ionic compounds are referred to as salts as they can also be formed by the neutralization reaction of an Arrhenius base like NaOH with an Arrhenius acid like HCl
: NaOH + HCl → NaCl + HO
The salt NaCl is then said to consist of the acid rest Cl and the base rest Na.
The removal of electrons to form the cation is endothermic, raising the systems overall energy. There may also be energy changes associated with breaking of existing bonds or the addition of more than one electron to form anions. However, the action of the anions accepting the cation's valence electrons and the subsequent attraction of the ions to each other releases (lattice) energy and, thus, lowers the overall energy of the system.
Ionic bonding will occur only if the overall energy change for the reaction is favorable. In general, the reaction is exothermic, but, e.g., the formation of mercuric oxide (HgO) is endothermic. The charge of the resulting ions is a major factor in the strength of ionic bonding, e.g. a salt CA is held together by electrostatic forces roughly four times weaker than CA according to Coulomb's law, where C and A represent a generic cation and anion respectively. The sizes of the ions and the particular packing of the lattice are ignored in this rather simplistic argument. | 0 | Theoretical and Fundamental Chemistry |
Sweden and Finland are furthest along in committing to a particular disposal technology, while many others reprocess spent fuel or contract with France or Great Britain to do it, taking back the resulting plutonium and high-level waste. "An increasing backlog of plutonium from reprocessing is developing in many countries... It is doubtful that reprocessing makes economic sense in the present environment of cheap uranium."
In many European countries (e.g., Britain, Finland, the Netherlands, Sweden, and Switzerland) the risk or dose limit for a member of the public exposed to radiation from a future high-level nuclear waste facility is considerably more stringent than that suggested by the International Commission on Radiation Protection or proposed in the United States. European limits are often more stringent than the standard suggested in 1990 by the International Commission on Radiation Protection by a factor of 20, and more stringent by a factor of ten than the standard proposed by the U.S. Environmental Protection Agency (EPA) for Yucca Mountain nuclear waste repository for the first 10,000 years after closure.
The U.S. EPA's proposed standard for greater than 10,000 years is 250 times more permissive than the European limit. The U.S. EPA proposed a legal limit of a maximum of 3.5 millisieverts (350 millirem) each annually to local individuals after 10,000 years, which would be up to several percent of the exposure currently received by some populations in the highest natural background regions on Earth, though the U.S. United States Department of Energy (DOE) predicted that received dose would be much below that limit. Over a timeframe of thousands of years, after the most active short half-life radioisotopes decayed, burying U.S. nuclear waste would increase the radioactivity in the top 2000 feet of rock and soil in the United States (10 million km) by approximately 1 part in 10 million over the cumulative amount of natural radioisotopes in such a volume, but the vicinity of the site would have a far higher concentration of artificial radioisotopes underground than such an average. | 0 | Theoretical and Fundamental Chemistry |
In fluid dynamics, drop impact occurs when a drop of liquid strikes a solid or liquid surface. The resulting outcome depends on the properties of the drop, the surface, and the surrounding fluid, which is most commonly a gas. | 1 | Applied and Interdisciplinary Chemistry |
"Promoting and advancing the science of chemical engineering in all its branches, promoting competence and a commitment to sustainable development, advancing the discipline for the benefit of society and supporting the professional development of members." | 1 | Applied and Interdisciplinary Chemistry |
The Hammond–Leffler postulate states that the structure of the transition state more closely resembles either the products or the starting material, depending on which is higher in enthalpy. A transition state that resembles the reactants more than the products is said to be early, while a transition state that resembles the products more than the reactants is said to be late. Thus, the Hammond–Leffler Postulate predicts a late transition state for an endothermic reaction and an early transition state for an exothermic reaction.
A dimensionless reaction coordinate that quantifies the lateness of a transition state can be used to test the validity of the Hammond–Leffler postulate for a particular reaction. | 0 | Theoretical and Fundamental Chemistry |
* Ganges–Brahmaputra, India and Bangladesh
* Indus River, India and Pakistan
* Sittaung River, Burma
* Qiantang River, China, which has the world's largest bore, up to high, traveling at up to
* Batang Lupar or Lupar River, near Sri Aman, Malaysia. The tidal bore is locally known as benak.
* Batang Sadong or Sadong River, Sarawak, Malaysia.
* Bono, Kampar River, at Meranti Bay, Pelalawan, Indonesia. The phenomenon is feared by the locals to sink ships. It is reported to break up to inland, but usually up to with height. | 1 | Applied and Interdisciplinary Chemistry |
One of the challenges of DNA computing is its speed. While DNA as a substrate is biologically compatible i.e. it can be used at places where silicon technology cannot, its computation speed is still very slow. For example, the square-root circuit used as a benchmark in field took over 100 hours to complete. While newer ways with external enzyme sources are reporting faster and more compact circuits, Chatterjee et al. demonstrated an interesting idea in the field to speed up computation through localized DNA circuits, a concept being further explored by other groups. This idea, while originally proposed in the field of computer architecture, has been adopted in this field as well. In computer architecture, it is very well-known that if the instructions are executed in sequence, having them loaded in the cache will inevitably lead to fast performance, also called the principle of localization. This is because with instructions in fast cache memory, there is no need swap them in and out of main memory, which can be slow. Similarly, in [https://www.nature.com/articles/nnano.2017.127 localized DNA computing], the DNA strands responsible for computation are fixed on a breadboard-like substrate ensuring physical proximity of the computing gates. Such localized DNA computing techniques have shown to potentially reduce the computation time by [https://www.nature.com/articles/nnano.2017.127 orders of magnitude]. | 1 | Applied and Interdisciplinary Chemistry |
Energy-dispersive x-ray spectroscopy (EDS) and electron energy loss spectroscopy (EELS) are commonly used techniques to both qualitatively and quantitatively probe the composition of samples in the TEM. A primary challenge in the quantitative accuracy of both techniques is the phenomenon of channelling. Put simply, in a crystalline solid, the probability of interaction between an electron and ion in the lattice depends strongly on the momentum (direction and velocity) of the electron. When probing a sample under diffraction conditions near a zone axis, as is often the case in EDS and EELS applications, channelling can have a large impact on the effective interaction of the incident electrons with specific ions in the crystal structure. In practice, this can lead to erroneous measurements of composition that depend strongly on the orientation and thickness of the sample and the accelerating voltage. Since PED entails an integration over incident directions of the electron probe, and generally does not include beams parallel to the zone axis, the detrimental channeling effects outlined above can be minimized, yielding far more accurate composition measurements in both techniques. | 0 | Theoretical and Fundamental Chemistry |
In the United States, clean coal was mentioned by former President George W. Bush on several occasions, including his 2007 State of the Union Address. Bushs position was that carbon capture and storage technologies should be encouraged as one means to reduce the countrys dependence on foreign oil.
During the US Presidential campaign for 2008, both candidates John McCain and Barack Obama expressed interest in the development of CCS technologies as part of an overall comprehensive energy plan. The development of pollution mitigation technologies could also create export business for the United States or any other country working on it.
The American Reinvestment and Recovery Act, signed in 2009 by President Obama, allocated $3.4 billion for advanced carbon capture and storage technologies, including demonstration projects.
Former Secretary of State Hillary Clinton has said that "we should strive to have new electricity generation come from other sources, such as clean coal and renewables", and former Energy Secretary Dr. Steven Chu has said that "It is absolutely worthwhile to invest in carbon capture and storage", noting that even if the U.S. and Europe turned their backs on coal, developing nations like India and China would likely not.
During the first 2012 United States presidential election debate, Mitt Romney expressed his support for clean coal, and claimed that current federal policies were hampering the coal industry.
During the Trump administration, an was set up within the United States Department of Energy, but was abolished in the Biden administration. | 1 | Applied and Interdisciplinary Chemistry |
Lipoidal estradiol (LE2) is the variety of endogenous C17β long-chain fatty acid esters of estradiol which are formed as metabolites of estradiol. Important examples of these esters include estradiol arachidonate, estradiol lineolate, estradiol oleate, estradiol palmitate, and estradiol stearate. LE2 are estrogens but do not bind to the estrogen receptor, instead acting as prohormones of estradiol. Relative to estradiol, they have far longer-lasting durations of effect due to their much slower rates of metabolism and clearance. It has been hypothesized that LE2 may serve as a store of estrogen for when estradiol levels become low. LE2 are highly lipophilic and hydrophobic and are found in highest concentrations in adipose tissue and other estrogen-sensitive tissues and in low but detectable concentrations in circulation, with none excreted in urine. They have been referred to as the "endogenous counterparts of the synthetic esters of estrogens" like estradiol valerate and estradiol cypionate.
Two of the estradiol esters that compose LE2, estradiol palmitate and estradiol stearate, have been developed and marketed for medical use as long-acting estrogens for use via depot intramuscular injection.
Estradiol is esterified into LE2 by lecithin–cholesterol acyltransferase (LCAT). | 1 | Applied and Interdisciplinary Chemistry |
Loo was born in Kuala Lumpur, Malaysia, and later lived in Taipei, Taiwan, where she attended Taipei American School. She moved to the United States to attend the University of Pennsylvania, where she completed bachelor's degrees in chemical engineering and materials science in 1996. She then pursued graduate studies at Princeton University, where she received a Ph.D. in chemical engineering in 2001 after completing a doctoral dissertation titled "Controlled polymer crystallization through block copolymer self-assembly." | 1 | Applied and Interdisciplinary Chemistry |
Nutriomics is the science that studies the food and nutrition domains comprehensively to improve consumer's well-being and health.
More specifically Nutriomics approaches are used to evaluate the effects of different diets to promote health and modulate the risk of disease development. | 1 | Applied and Interdisciplinary Chemistry |
Snapping involves two separate parts of the thread, both containing a bulky group. one part of the thread is then threaded to the macrocycle, forming a semi rotaxane, and end is closed of by the other part of the thread forming the rotaxane. | 0 | Theoretical and Fundamental Chemistry |
In 2005, Suskiewicz et al. classified the enzyme YwIE as a tyrosine phosphatase. And Kirstein et al. (2005) found that McsB is a tyrosine kinase that needs McsA to become activated. They also found that the interaction of McsA and McsB with CtsR results in the formation of a 3-protein complex that stops the binding of CtsR to its target DNA and leads to subsequent phosphorylation of McsB, McsA, and CtsR. | 1 | Applied and Interdisciplinary Chemistry |
PPA is known as a self-immolative material which depolymerizes through endcap cleavage in response to a specific stimulus. For this reason, several PPA polymers with different endcaps have been synthesized and used as self-immolative materials for sensing toxic and specific compounds. | 0 | Theoretical and Fundamental Chemistry |
Erwin Hiebert died in Waltham, Massachusetts in November 2012, shortly after his wife of 69 years died in September 2012. He was survived by their two daughters, Catherine and Margaret, a son Thomas, and seven grandchildren. Catherine Hiebert Beissinger became a professor of Slavic languages and literatures at Princeton University. Thomas Hiebert became a professor of music at California State University, Fresno. | 0 | Theoretical and Fundamental Chemistry |
Hyperspectral imaging can provide information about the chemical constituents of materials which makes it useful for waste sorting and recycling. It has been applied to distinguish between substances with different fabrics and to identify natural, animal and synthetic fibers. HSI cameras can be integrated with machine vision systems and, via simplifying platforms, allow end-customers to create new waste sorting applications and other sorting/identification applications. A system of machine learning and hyperspectral camera can distinguish between 12 different types of plastics such as PET and PP for automated separation of waste of, as of 2020, highly unstandardized plastics products and packaging. | 0 | Theoretical and Fundamental Chemistry |
Enantiopure tert-butanesulfinamide can be prepared by enantioselective oxidation of inexpensive di-tert-butyl disulfide to the thiosulfinate followed by disulfide bond cleavage by lithium amide. In the original scope the chiral ligand used together with vanadyl acetylacetonate was prepared by condensing an optically pure chiral aminoindanol with 3,5-di-tert-butyl salicylaldehyde. | 0 | Theoretical and Fundamental Chemistry |
Typically, absorbance of a dissolved substance is measured using absorption spectroscopy. This involves shining a light through a solution and recording how much light and what wavelengths were transmitted onto a detector. Using this information, the wavelengths that were absorbed can be determined. First, measurements on a "blank" are taken using just the solvent for reference purposes. This is so that the absorbance of the solvent is known, and then any change in absorbance when measuring the whole solution is made by just the solute of interest. Then measurements of the solution are taken. The transmitted spectral radiant flux that makes it through the solution sample is measured and compared to the incident spectral radiant flux. As stated above, the spectral absorbance at a given wavelength is
The absorbance spectrum is plotted on a graph of absorbance vs. wavelength.
An Ultraviolet-visible spectroscopy#Ultraviolet–visible spectrophotometer will do all this automatically. To use this machine, solutions are placed in a small cuvette and inserted into the holder. The machine is controlled through a computer and, once it has been "blanked", automatically displays the absorbance plotted against wavelength. Getting the absorbance spectrum of a solution is useful for determining the concentration of that solution using the Beer–Lambert law and is used in HPLC. | 0 | Theoretical and Fundamental Chemistry |
Locally grown non-predatory fish can be added to surface flow constructed wetlands to eliminate or reduce pests, such as mosquitos.
Stormwater wetlands provide habitat for amphibians but the pollutants they accumulate can affect the survival of larval stages, potentially making them function as "ecological traps". | 1 | Applied and Interdisciplinary Chemistry |
The solution in the middle deck is found to be
where is referred to as the displacement function and is referred to as the pressure function, to be determined from the upper and lower deck problems. Note that in the correction to the Blasius stream function is of the order , although the pressure perturbation is only order | 1 | Applied and Interdisciplinary Chemistry |
In addition to Saturns methane cycle some studies suggest an ammonia cycle induced by photolysis similar to Jupiters.
The cycles of its moons are of particular interest. Observations by Cassini–Huygens of Titan's atmosphere and interactions with its liquid mantle give rise to several active chemical cycles including a methane, hydrocarbon, hydrogen, and carbon cycles. Enceladus has an active hydrological, silicate and possibly a nitrogen cycle. | 0 | Theoretical and Fundamental Chemistry |
The strength of the adhesion between two materials depends on which of the above mechanisms occur between the two materials, and the surface area over which the two materials contact. Materials that wet against each other tend to have a larger contact area than those that do not. Wetting depends on the surface energy of the materials.
Low surface energy materials such as polyethylene, polypropylene, polytetrafluoroethylene and polyoxymethylene are difficult to bond without special surface preparation.
Another factor determining the strength of an adhesive contact is its shape. Adhesive contacts of complex shape begin to detach at the "edges" of the contact area. The process of destruction of adhesive contacts can be seen in the film. | 0 | Theoretical and Fundamental Chemistry |
Raytec Vision is a camera and sensor-based manufacturer based in Parma and specialized in food sorting. The applications of Raytec Vision's machines are many: tomatoes, tubers, fruit, fresh cut, vegetables and confectionery products. Each machine can separate good products from wastes, foreign bodies and defects and guarantees high levels of food safety for the final consumer. | 0 | Theoretical and Fundamental Chemistry |
In the case of oxidizing treatments, spectra taken from treated surfaces will indicate the presence of functionalities in carbonyl and hydroxyl regions according to the Infrared spectroscopy correlation table. | 0 | Theoretical and Fundamental Chemistry |
Some of the most commonly-used biocompatible materials (or biomaterials) are polymers due to their inherent flexibility and tunable mechanical properties. Medical devices made of plastics are often made of a select few including: cyclic olefin copolymer (COC), polycarbonate (PC), polyetherimide (PEI), medical grade polyvinylchloride (PVC), polyethersulfone (PES), polyethylene (PE), polyetheretherketone (PEEK) and even polypropylene (PP). To ensure biocompatibility, there are a series of regulated tests that material must pass to be certified for use. These include the United States Pharmacopoeia IV (USP Class IV) Biological Reactivity Test and the International Standards Organization 10993 (ISO 10993) Biological Evaluation of Medical Devices. The main objective of biocompatibility tests is to quantify the acute and chronic toxicity of material and determine any potential adverse effects during use conditions, thus the tests required for a given material are dependent on its end-use (i.e. blood, central nervous system, etc.). | 1 | Applied and Interdisciplinary Chemistry |
Tee-wyes are similar to tees, except for angling the branch line to reduce friction and turbulence. They are commonly used to attach a vertical drainpipe to a horizontal one, reducing the deposition of entrained solids at the junction. Wyes and combo wyes follow a long-sweep pattern relative to sanitary tees and other short-sweep bends, which have a smaller radius and require less space.
Wyes also have industrial applications. Although low-priced wyes are often spot-welded, industrial-strength wyes are flash-welded at each seam. In long-distance pipeline applications, a specialized wye is used to allow insertion of pigging to keep pipes clear and flowing. | 1 | Applied and Interdisciplinary Chemistry |
As far back as 1905, marine researchers attempted to develop an equation to be used as the standard in establishing the relationship between solar irradiance and photosynthetic production. Several groups had relative success, but in 1976 a comparison study conducted by Alan Jassby and Trevor Platt, researchers at the Bedford Institute of Oceanography in Dartmouth, Nova Scotia, reached a conclusion that solidified the way in which a PI curve is developed. After evaluating the eight most-used equations, Jassby and Platt argued that the PI curve can be best approximated by a hyperbolic tangent function, at least until photoinhibition is reached. | 0 | Theoretical and Fundamental Chemistry |
During the 1980s, AT&T Bell Laboratories explored the use of nitrobenzyl-based PPGs as photoresists. Over the course of the decade, they developed a deep UV positive-tone photoresist where the protected substrate was added to a copolymer of poly(methyl methacrylate) and poly(methacrylic acid). Initially, the blend was insoluble. However, upon exposure to 260 ± 20 nm light, the PPG would be removed yielding 2-nitrosobenzaldehyde and a carboxylic acid that was soluble in aqueous base. | 0 | Theoretical and Fundamental Chemistry |
In 1909, Schott received the Liebig Medal from the Association of German Chemists.
Otto-Schott-Straße in Jena, Germany, the location of Schotts home, was renamed in Schotts honor. The Schott Glass Museum is on the same premises. Both can be visited. The Schott Glass Museum displays developments in glass science beginning with the innovations of Otto Schott.
Since 1991, the Otto Schott Research Award has been presented every two years to meritorious researchers in the field of glass science and ceramics science. The award is organized and funded by the Abbe Fund of the Carl Zeiss Foundation. | 0 | Theoretical and Fundamental Chemistry |
Magnetohydrodynamics is the multidisciplinary study of the flow of electrically conducting fluids in electromagnetic fields. Examples of such fluids include plasmas, liquid metals, and salt water. The fluid flow equations are solved simultaneously with Maxwell's equations of electromagnetism. | 1 | Applied and Interdisciplinary Chemistry |
Nuclear receptor-interacting protein 1 (NRIP1) also known as receptor-interacting protein 140 (RIP140) is a protein that in humans is encoded by the NRIP1 gene. | 1 | Applied and Interdisciplinary Chemistry |
Choi Yang-do (; born 1953) is a South Korean agricultural biotechnologist. His research focuses on the development of crops with stress-tolerant and yield-enhancing traits. One of his academic achievements is the discovery of a new jasmonate which enhances resistance against external stress of the crop. Choi is currently professor at Seoul National University in South Korea. | 1 | Applied and Interdisciplinary Chemistry |
The importance of motor proteins in cells becomes evident when they fail to fulfill their function. For example, kinesin deficiencies have been identified as the cause for Charcot-Marie-Tooth disease and some kidney diseases. Dynein deficiencies can lead to chronic infections of the respiratory tract as cilia fail to function without dynein. Numerous myosin deficiencies are related to disease states and genetic syndromes. Because myosin II is essential for muscle contraction, defects in muscular myosin predictably cause myopathies. Myosin is necessary in the process of hearing because of its role in the growth of stereocilia so defects in myosin protein structure can lead to Usher syndrome and non-syndromic deafness. | 0 | Theoretical and Fundamental Chemistry |
Design errors arise when the desired use case was not properly accounted for, leading to a ineffective design, such as the stress state in service or potential corrosive agents in the service environment. Design errors often include dimensioning and materials selection, but it can also be the complete design. | 1 | Applied and Interdisciplinary Chemistry |
Modafinil was used by the French Foreign Legion, U.S. Air Force, and U.S. Marine infantry during the Gulf War to enhance "operational tempo" (a term that denotes the speed and intensity at which military operations or activities are executed), aiming to optimize the overall performance and efficiency of the unit.
Armed forces in various countries, including the United States, the United Kingdom, India, and France, have considered modafinil as an alternative to traditional amphetamines for managing sleep deprivation in combat or extended missions. The US military approved modafinil for specific Air Force missions, replacing amphetamines for fatigue management. The use of modafinil in military contexts without sleep deprivation is not recommended due to inconclusive evidence on its cognitive enhancement benefits and potential risks of adverse effects.
Modafinil is also available to astronauts aboard the International Space Station for the management of fatigue caused by circadian dyssynchrony in orbit. | 0 | Theoretical and Fundamental Chemistry |
Human genes encoding heterogeneous nuclear ribonucleoproteins include:
* HNRNPA0, HNRNPA1, HNRNPA1L1, HNRNPA1L2, HNRNPA3, HNRNPA2B1
* HNRNPAB
* HNRNPB1
* HNRNPC, HNRNPCL1
* HNRNPD (AUF1), HNRPDL
* HNRNPF
* HNRNPG (RBMX)
* HNRNPH1, HNRNPH2, HNRNPH3
* HNRNPI (PTB)
* HNRNPK
* HNRNPL, HNRPLL
* HNRNPM
* HNRNPP2 (FUS/TLS)
* HNRNPR
* HNRNPQ (SYNCRIP)
* HNRNPU, HNRNPUL1, HNRNPUL2, HNRNPUL3
* FMR1 | 1 | Applied and Interdisciplinary Chemistry |
Silicone foam is a synthetic rubber product used in gasketing, sheets and firestops. It is available in solid, cured form as well as in individual liquid components for field installations. | 0 | Theoretical and Fundamental Chemistry |
Nitrate reductase was suggested to initiate nanoparticle formation by many fungi including Penicillium species, while several enzymes, α-NADPH-dependent reductases, nitrate-dependent reductases and an extracellular shuttle quinone, were implicated in silver nanoparticle synthesis for Fusarium oxysporum. Jain et al. (2011) indicated that silver nanoparticle synthesis for A. flavus occurs initially by a "33kDa" protein followed by a protein (cystein and free amine groups) electrostatic attraction which stabilizes the nanoparticle by forming a capping agent. Intracellular silver and gold nanoparticle synthesis is not fully understood but similar fungal cell wall surface electrostatic attraction, reduction, and accumulation has been proposed. External gold nanoparticle synthesis by P. chrysosporium was attributed to laccase, while intracellular gold nanoparticle synthesis was attributed to ligninase. | 0 | Theoretical and Fundamental Chemistry |
The slip-line theory was co-developed by Hilda Geiringer in the early 1930s. She developed the Geiringer equations, which simplify the process of calculating the deformation. | 1 | Applied and Interdisciplinary Chemistry |
There are generally five types of toxicities: chemical, biological, physical, radioactive and behavioural.
Disease-causing microorganisms and parasites are toxic in a broad sense but are generally called pathogens rather than toxicants. The biological toxicity of pathogens can be difficult to measure because the threshold dose may be a single organism. Theoretically one virus, bacterium or worm can reproduce to cause a serious infection. If a host has an intact immune system, the inherent toxicity of the organism is balanced by the host's response; the effective toxicity is then a combination. In some cases, e.g. cholera toxin, the disease is chiefly caused by a nonliving substance secreted by the organism, rather than the organism itself. Such nonliving biological toxicants are generally called toxins if produced by a microorganism, plant, or fungus, and venoms if produced by an animal.
Physical toxicants are substances that, due to their physical nature, interfere with biological processes. Examples include coal dust, asbestos fibres or finely divided silicon dioxide, all of which can ultimately be fatal if inhaled. Corrosive chemicals possess physical toxicity because they destroy tissues, but are not directly poisonous unless they interfere directly with biological activity. Water can act as a physical toxicant if taken in extremely high doses because the concentration of vital ions decreases dramatically with too much water in the body. Asphyxiant gases can be considered physical toxicants because they act by displacing oxygen in the environment but they are inert, not chemically toxic gases.
Radiation can have a toxic effect on organisms.
Behavioral toxicity refers to the undesirable effects of essentially therapeutic levels of medication clinically indicated for a given disorder (DiMascio, Soltys and Shader, 1970). These undesirable effects include anticholinergic effects, alpha-adrenergic blockade, and dopaminergic effects, among others. | 1 | Applied and Interdisciplinary Chemistry |
Winnowing is a process by which chaff is separated from grain. It can also be used to remove pests from stored grain. Winnowing usually follows threshing in grain preparation. In its simplest form, it involves throwing the mixture into the air so that the wind blows away the lighter chaff, while the heavier grains fall back down for recovery. Techniques included using a winnowing fan (a shaped basket shaken to raise the chaff) or using a tool (a winnowing fork or shovel) on a pile of harvested grain. | 0 | Theoretical and Fundamental Chemistry |
Solar energy conversion has the potential for many positive social impacts, especially in rural areas that did not previously have grid-based energy access. In many off-grid areas, the solar-electric conversion is the fastest growing form of energy procurement. This is especially true at latitudes within 45° north or south of the Equator, where solar irradiance is more constant throughout the year and where the bulk of the developing world's population lives. From a health perspective, solar home systems can replace kerosene lamps (frequently found in rural areas), which can cause fires and emit pollutants like carbon monoxide (CO), nitric oxides (NOx), and sulfur dioxide (SO2) that adversely affect air quality and can cause impair lung function and increase tuberculosis, asthma, and cancer risks. In such areas, solar energy access has been shown to save rural residents the time and money needed to purchase and transport kerosene, thereby increasing productivity and lengthening business hours.
In addition to energy access, these communities gain energy independence, meaning they are not reliant on a third-party electricity provider. The concept of energy independence is relatively new; for the vast majority of the 20th century, energy analyses were purely technical or financial and did not include social impact analysis. A 1980 study concluded that access to renewable energy would promote values conducive to larger societal benefit as opposed to personal promotion. While some academics argue that historically the parties in control of energy sources are those that create social hierarchies, this type of analysis became less “radical” and more mainstream after the introduction of technologies that enabled solar energy conversion. | 0 | Theoretical and Fundamental Chemistry |
Storm drains are often unable to manage the quantity of rain that falls during heavy rains and/or storms. When storm drains are inundated, basement and street flooding can occur. Unlike catastrophic flooding events, this type of urban flooding occurs in built-up areas where human-made drainage systems are prevalent. Urban flooding is the primary cause of sewer backups and basement flooding, which can affect properties repeatedly.
Clogged drains also contribute to flooding by the obstruction of storm drains. Communities or cities can help reduce this by cleaning leaves from the storm drains to stop ponding or flooding into yards. Snow in the winter can also clog drains when there is an unusual amount of rain in the winter and snow is plowed atop storm drains.
Runoff into storm sewers can be minimized by including sustainable urban drainage systems (UK term) or low impact development or green infrastructure practices (US terms) into municipal plans. To reduce stormwater from rooftops, flows from eaves troughs (rain gutters and downspouts) may be infiltrated into adjacent soil, rather than discharged into the storm sewer system. Storm water runoff from paved surfaces can be directed to unlined ditches (sometimes called swales or bioswales) before flowing into the storm sewers, again to allow the runoff to soak into the ground. Permeable paving materials can be used in building sidewalks, driveways and in some cases, parking lots, to infiltrate a portion of the stormwater volume.
Many areas require that properties have detention tanks that temporarily hold rainwater runoff, and restrict the outlet flow to the public sewer. This lessens the risk of overburdening the public sewer during heavy rain. An overflow outlet may also connect higher on the outlet side of the detention tank. This overflow prevents the detention tank from completely filling. Restricting water flow and temporarily holding the water in a detention tank public this way makes it far less likely for rain to overwhelm the sewers. | 1 | Applied and Interdisciplinary Chemistry |
To make a geometrically stable structure in a mineral, atoms must fit together in terms of both their size and charge. The atoms have to fit together so that their electron shells can interact with one another and they also have to produce a neutral molecule. For these reasons the sizes and electron shell structure of atoms determine what element combinations are possible and the geometrical form that various minerals take. Because electrons are donated and received, it is the ionic radius of the element that controls the size and determines how atoms fit together in minerals. | 0 | Theoretical and Fundamental Chemistry |
Formylation of octabase prior to cyclization avoids ether cleavage as a side reaction and yields higher than without N-substitution or N-methylation. In this example, the purification was done by formation of a brucine salt.
This process has also been patented by Roche. | 0 | Theoretical and Fundamental Chemistry |
The earliest Chinese manual of materia medica, the Shennong Bencao Jing (Shennong Emperors Classic of Materia Medica), was compiled in the 1st century AD during the Han dynasty, attributed to the mythical Shennong. It lists some 365 medicines, of which 252 are herbs. Earlier literature included lists of prescriptions for specific ailments, exemplified by the Recipes for Fifty-Two Ailments found in the Mawangdui tomb, which was sealed in 168 BC. Succeeding generations augmented the Shennong Bencao Jing, as in the Yaoxing Lun (Treatise on the Nature of Medicinal Herbs'), a 7th-century Tang dynasty treatise on herbal medicine. | 1 | Applied and Interdisciplinary Chemistry |
The Golm Metabolome Database (GMD) is a gas chromatography (GC) – mass spectrometry (MS) reference library dedicated to metabolite profiling experiments and comprises mass spectral and retention index (RI) information for non-annotated mass spectral tags (MSTs, mass spectral information with retention time attached indices) together with data of a multitude of already identified metabolites and reference substances. The GMD is hosted at the Max Planck Institute of Molecular Plant Physiology in Golm district of Potsdam, Germany. | 0 | Theoretical and Fundamental Chemistry |
Thermal conductivity, viscosity, density, specific heat, and surface tension are considered some main thermophysical properties of nanofluids. Various parameters like nanoparticle type, size, and shape, volume concentration, fluid temperature, and nanofluid preparation method have effect on thermophysical properties of nanofluids.
*Viscosity of nanofluids
*Density of nanofluids
*Thermal conductivity of nanofluids | 0 | Theoretical and Fundamental Chemistry |
An electrolithoautotroph is an organism which feeds on electricity. These organisms use electricity to convert carbon dioxide into organic matter by using electrons directly taken from solid-inorganic electron donors. Electrolithoautotrophs are microorganisms which are found in the deep crevices of the ocean. The warm, mineral-rich environment provides a rich source of nutrients. The electron source for carbon assimilation from diffusible Fe ions to an electrode under the condition that electrical current is the only source of energy and electrons. Electrolithoautotrophs form a third metabolic pathway compared to photosynthesis (plants converting light into sugar) and chemosynthesis (bacteria converting chemical energy into food). | 1 | Applied and Interdisciplinary Chemistry |
Non-competitive inhibition is a type of enzyme inhibition where the inhibitor reduces the activity of the enzyme and binds equally well to the enzyme whether or not it has already bound the substrate. This is unlike competitive inhibition, where binding affinity for the substrate in the enzyme is decreased in the presence of an inhibitor.
The inhibitor may bind to the enzyme whether or not the substrate has already been bound, but if it has a higher affinity for binding the enzyme in one state or the other, it is called a mixed inhibitor. | 1 | Applied and Interdisciplinary Chemistry |
Nature uses pigments, mainly chlorophylls, to absorb a broad part of the visible spectrum. Artificial systems can use either one type of pigment with a broad absorption range or combine several pigments for the same purpose.
Ruthenium polypyridine complexes, in particular tris(bipyridine)ruthenium(II) and its derivatives, have been extensively used in hydrogen photoproduction due to their efficient visible light absorption and long-lived consequent metal-to-ligand charge transfer excited state, which makes the complexes strong reducing agents. Other noble metal-containing complexes used include ones with platinum, rhodium and iridium.
Metal-free organic complexes have also been successfully employed as photosensitizers. Examples include eosin Y and rose bengal. Pyrrole rings such as porphyrins have also been used in coating nanomaterials or semiconductors for both homogeneous and heterogeneous catalysis.
As part of current research efforts artificial photonic antenna systems are being studied to determine efficient and sustainable ways to collect light for artificial photosynthesis. Gion Calzaferri (2009) describes one such antenna that uses zeolite L as a host for organic dyes, to mimic plant's light collecting systems. The antenna is fabricated by inserting dye molecules into the channels of zeolite L. The insertion process, which takes place under vacuum and at high temperature conditions, is made possible by the cooperative vibrational motion of the zeolite framework and of the dye molecules. The resulting material may be interfaced to an external device via a stopcock intermediate. | 0 | Theoretical and Fundamental Chemistry |
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