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Patch dynamics is a term used in physics to bridge, using algorithms, the models describing macroscale behavior and to predict large-scale patterns in fluid flow. It uses locally averaged properties of short space-time scales to advance and predict long space-time scale dynamics.
In patch dynamics and finite difference approximations, the macroscale variables are defined at the grid points of a mesh chosen to resolve the solution. The standard PDE adaptive grid methods can be used to resolve gradients in the macroscale solution. Both patch dynamics and finite difference methods generate time derivatives at mesh points; these time derivatives then help advance the solution in time. | 1 | Applied and Interdisciplinary Chemistry |
Perey was elected to the French Academy of Sciences in 1962, making her the first woman elected to the Institut de France. Although a significant step, her election as a "corresponding member" rather than a full member came with limited privileges.
*The French Academy of Science Wilde Prize (1950)
*The French Academy of Science Le Conte Prize (1960)
*The City of Paris Science Grand Prize (1960)
*Officier of the Légion d'Honneur (1960)
* Grand Prix de la Ville de Paris (1960)
* Elected correspondante of the Académie des Sciences (Paris, 1962). First woman to be elected to the Académie since its founding in 1666.
* Lavoisier Prize of the Académie des Sciences (1964)
* Silver Medal of the Société Chimique de France (1964)
* Commandeur of the Ordre National du Mérite (1974) | 1 | Applied and Interdisciplinary Chemistry |
*Xenobiotics in the Urban Water Cycle: Mass Flows, Environmental Processes, Mitigation, and Treatment Strategies (2010)
*Wastewater Reuse and Current Challenges, The Handbook of Environmental Chemistry Series, 44, Springer, (2016) , ISSN: 1867-979X (print), ISSN: 1616-864X (electronic).
*Advanced Treatment Technologies for Urban Wastewater Reuse, The Handbook of Environmental Chemistry Series, 45, Springer, (2016) , ISSN: 1867-979X (print), ISSN: 1616-864X (electronic)
*The Secret Handbook of the Blue Circle (2019) in English, Turkish and Greek (2019) | 1 | Applied and Interdisciplinary Chemistry |
Artificial transactivation of a gene is achieved by inserting it into the genome at the appropriate area as transactivator gene adjoined to special promoter regions of DNA. The transactivator gene expresses a transcription factor that binds to specific promoter region of DNA. By binding to the promoter region of a gene, the transcription factor causes that gene to be expressed. The expression of one transactivator gene can activate multiple genes, as long as they have the same, specific promoter region attached. Because the expression of the transactivator gene can be controlled, transactivation can be used to turn genes on and off. If this specific promoter region is also attached to a reporter gene, we can measure when the transactivator is being expressed. | 1 | Applied and Interdisciplinary Chemistry |
A Shigemi tube is a microscale NMR tube used with an ordinary-size NMR tube. Shigemi tubes may be appropriate for protein NMR experiments, where only a smaller sample is available. A corresponding smaller solvent volume is desired to maintain a higher sample concentration. The reduced sample depth is compensated for by solid glass on the NMR tube beneath the level of sample, which varies for the make of spectrometer. Once air bubbles have been expelled, the plunger is secured to the tube proper by parafilm. Ideally, the tubes are matched with the deuterated solvent used to have better spectrum resolution. | 0 | Theoretical and Fundamental Chemistry |
Quantum efficiency is a unitless number that measures the sensitivity of the photocathode to light. It is the ratio of the number of electrons emitted to the number of incident photons. This property depends on the wavelength of light being used to illuminate the photocathode. For many applications, QE is the most important property as the photocathodes are used solely for converting photons into an electrical signal.
Quantum efficiency may be calculated from photocurrent (), laser power (), and either the photon energy () or laser wavelength () using the following equation. | 0 | Theoretical and Fundamental Chemistry |
Isaac Newton wrote extensively upon the historical topic of chronology. In 1728 The Chronology of Ancient Kingdoms Amended, an approximately 87,000-word composition that details the rise and history of various ancient kingdoms was published. The publication date of this work occurred after his death, although the majority of it had been reviewed for publication by Newton himself shortly before he died. As such, this work represents one of his last known personally reviewed publications. Sometime around 1701 he also produced a thirty page unpublished treatise entitled "The Original of Monarchies" detailing the rise of several monarchs throughout antiquity and tracing them back to the biblical figure of Noah.
Newtons chronological writing is Eurocentric, with the earliest records focusing upon Greece, Anatolia, Egypt, and the Levant. Many of Newtons dates do not correlate with current historical knowledge. While Newton mentions several pre-historical events found within the Bible, the oldest actual historical date he provides is 1125 BC. In this entry he mentions Mephres, a ruler over Upper Egypt from the territories of Syene to Heliopolis, and his successor Misphragmuthosis. However, during 1125 BC the Pharaoh of Egypt is now understood to be Ramesses IX.
Although some of the dates Newton provides for various events are accurate by 17th century standards, archaeology as a form of modern science did not exist in Newtons time. In fact, the majority of the conclusionary dates which Newton cites are based on the works of Herodotus, Pliny, Plutarch, Homer, and various other classical historians, authors, and poets; themselves often citing secondary sources and oral records of uncertain date. Newtons approach to chronology was focused upon gathering historical information from various sources found throughout antiquity and cataloguing them according to their appropriate date by his contemporary understanding, standards, and available source material. | 1 | Applied and Interdisciplinary Chemistry |
Organisms in Arctic waters are under high environmental stress such as extremely cold water. It is believed that this high stress environment will cause ocean acidification factors to have a stronger effect on these organisms. It could also cause these effects to appear in the Arctic before it appears in other parts of the ocean. There is a significant variation in the sensitivity of marine organisms to increased ocean acidification. Calcifying organisms generally exhibit larger negative responses from ocean acidification than non-calcifying organisms across numerous response variables, with the exception of crustaceans, which calcify but don't seem to be negatively affected. This is due, mainly, to the process of marine biogenic calcification, that calcifying organisms utilize. | 0 | Theoretical and Fundamental Chemistry |
IN belongs, both mechanistically and structurally, to the superfamily of polynucleotidyl transferases 10 and is composed of 288 amino acids that form the 32 kDa protein. Retroviruses encode their enzymes (protease, reverse transcriptase and integrase) with the POL gene with the 3´end encoding for IN.
IN is composed of 3 structurally independent, functional domains (see figure 1).:
1. The N-terminal domain (NTD) encompasses amino acids 1–50 and contains two histidine residues (His12 and His16) and two cysteine residues (Cys40 and Cys43), all of which are absolutely conserved and form a HHCC zinc-finger motif. Single mutations of any of these four residues reduce IN enzymatic activity. The HHCC zinc-finger motif chelates one zinc atom per IN monomer. The NTD is required for higher order multimer formation which appears to be its primary role. The multimerization requires zinc atom that stabilizes the fold.
2. The catalytic core domain (CCD), which encompasses amino acids 51- 212, contains the active site of IN but it can't catalyze integration in the absence of NTD and CTD (the C-terminal domain). CCD contains three absolutely conserved negatively charged amino acids; D64, D116 and E152. These amino acids form the DDE motif that coordinate divalent metal ions (Mg or Mn). These metal ions are essential for the catalysis of integration. CCD has a mixed β and α structure with five β-sheets and six α helices that are linked by flexible loops. The flexible loops allow conformational changes that are required for 3´processing of the viral DNA and strand transfer (STF) reactions which are two key steps of the integration reaction. CCD is essential for these steps and substitution of any of the residues in the DDE motif dramatically inhibits the activity of IN.
3. The C-terminal domain (CTD), which encompasses amino acids 213–288, binds DNA nonspecifically and its interaction with NTD and CCD is required for IN 3´-processing and strand-transfer activities. CTD is the least conserved of the three domains.
IN acts as a multimer and dimerization is required for the 3´-processing step, with tetrameric IN catalyzing the strand-transfer reaction. | 1 | Applied and Interdisciplinary Chemistry |
By integrating the differential form over the materials total surface , we arrive at the integral form of Fouriers law:
where (including the SI units):
* is the thermal power transferred by conduction (in W),
* is an oriented surface area element (in m).
The above differential equation, when integrated for a homogeneous material of 1-D geometry between two endpoints at constant temperature, gives the heat flow rate as
where
* is the time interval during which the amount of heat flows through a cross-section of the material,
* is the cross-sectional surface area,
* is the temperature difference between the ends,
* is the distance between the ends.
One can define the (macroscopic) thermal resistance of the 1-D homogeneous material:
With a simple 1-D steady heat conduction equation which is analogous to the Ohm's law for a simple electric resistance:
This law forms the basis for the derivation of the heat equation. | 1 | Applied and Interdisciplinary Chemistry |
Figure 1 summarizes the basic chemistry of formamide and its chemical connection with HCN and ammonium formate (NHHCOO), considering selected examples of preparative and degradative reactions.
The synthesis of purine from formamide was first reported in 1980. A series of studies building on this observation was started 20 years later: the synthesis of a large panel of prebiotically relevant compounds (including purine, adenine, cytosine, and 4(3H)pyrimidinone) in good yields was reported in 2001. These products were obtained by heating formamide in the presence of simple catalysts such as calcium carbonate (CaCO), silica (SiO), or alumina (AlO).
In addition to nucleobases, sugars, carboxylic acids, amino acids, as well as heterogeneous compounds of various classes, (including urea and carbodiimide) were also synthesized. The catalysts studied include, in addition to those mentioned, titanium oxides, clays, cosmic dust analogues, phosphates, iron sulphide minerals, zirconium minerals, borate minerals, or numerous materials of meteoritic origin encompassing iron, stony-iron, chondrites, and achondrites meteorites.
Various energy sources, including thermal energy, UV-radiation, irradiation with high-energy (terawatt) laser pulses, or slow protons were tested. Mimics of different formamide-based prebiotic scenarios have been reconstructed and analyzed, including space-wise solar wind irradiation of meteorites, dynamic chemical gardens, and meteorites in aqueous environments. It has been suggested that the stepwise decrease of the temperature of the prebiotic environment could induce a sequence of strongly non-equilibrium chemical events that led to the emergence of more and more complex species from formamide on the early Earth.
For each studied combination of catalyst/energy source/environment, formamide condensed into a variety of different prebiotically relevant compounds, each combination giving rise to a specific set of relatively complex molecules, usually encompassing several nucleobases, amino acids, and carboxylic acids. The highest level of complexity was attained for the formamide/meteorite system, using proton irradiation as the energy source, where the one-pot synthesis of four nucleosides (uridine, cytidine, adenosine, thymidine) was observed. So far, no other one-carbon atom compound has shown the versatility of products that can be formed from formamide under plausible prebiotic conditions in a one-pot chemistry (see Figure 2). <br />
In addition to its dual function of substrate and solvent in one-pot syntheses affording prebiotic compounds as complex as nucleosides and long aliphatic chains, it has been observed that formamide plays a role in the generation of molecules which are closer to the biological domain. In the presence of a phosphate source (e.g., phosphate minerals), formamide promotes the phosphorylation of nucleosides, leading to the formation of nucleotides, and strongly stimulates the non-enzymatic polymerization of 3’,5’ cyclic nucleotides, leading to the abiotic synthesis of RNA oligomers. This is the reason why formamide is considered a plausible medium for prebiotic phosphorylation reactions also in the “discontinuous synthesis” scenario of the origin of life. As well as phosphorylation, formamide has been shown to be a competent medium for the production of amino acid derivatives from their simple aldehyde and nitrile precursors, demonstrating that water is not the only solvent that this process can occur in. Most notably, formamide provides a medium for the prebiotic synthesis of cysteine derivatives, not considered previously considered plausible in strictly aqueous prebiotic environments. | 0 | Theoretical and Fundamental Chemistry |
During his extensive career, Moissan authored more than three hundred publications, won the 1906 Nobel Prize in Chemistry for the first isolation of fluorine, in addition to the Prix Lucaze, the Davy Medal, the Hofmann Medal, and the Elliott Cresson Medal. He was elected fellow of the Royal Society and The Chemical Society of London, served on the International Atomic Weights Committee and made a commandeur in the Légion d'honneur. | 0 | Theoretical and Fundamental Chemistry |
ATSDR has seven goals:
# Protect the public from environmental hazards and toxic exposures.
# Promote healthy environments.
# Advance the science of environmental public health.
# Support environmental public health practice.
# Educate communities, partners, and policy makers about environmental health risks and protective measures.
# Promote environmental justice and reduce health disparities associated with environmental exposures.
# Provide unique scientific and technical expertise to advance public health science and practice. | 1 | Applied and Interdisciplinary Chemistry |
The International Union of Biochemistry and Molecular Biology (IUBMB) is an international non-governmental organisation concerned with biochemistry and molecular biology. Formed in 1955 as the International Union of Biochemistry (IUB), the union has presently 79 member countries and regions (as of 2020). The Union is devoted to promoting research and education in biochemistry and molecular biology throughout the world, and gives particular attention to localities where the subject is still in its early development. | 1 | Applied and Interdisciplinary Chemistry |
Transportable semi-mobile installations have gained increasing popularity in the last two decades. They are enabled by the fact that complete sensor-based sorting systems are relatively compact in relation to the capacity in tonnes per hour. This is mainly because little infrastructure is needed. The picture shows a containerised sensor-based sorter which is applied in Chromitite sorting. The system is operated in conjunction with a Diesel-powered mobile crusher and screen. Material handling of the feed, undersize fraction, product and waste fraction is conducted using a wheel loader. The system is powered by a Diesel generator and a compressor station delivers the instrument quality air needed for the operation.
Semi-mobile installations are applied primarily to minimise material handling and save transport costs. Another reason for choosing the semi-mobile option for an installation is bulk testing of new ore bodies. Capacity of a system very much depends on the size fraction sorted, but a 250tph capacity is a good estimate for semi-mobile installations, considering a capacity of 125tph sorter feed and 125tph undersize material. During the last decade both generic plant designs and customised designs have been developed, for example in the framework of the i2mine project. | 0 | Theoretical and Fundamental Chemistry |
Mercury was surveyed by the MESSENGER mission with its Gamma-Ray Spectrometer. The K/U ratios for Mercury could range between 8,000 and 17,000 which would imply a volatile rich planet. However, metal/silicate partitioning data for K and U still needs additional experiments at the conditions of Mercury's core formation to understand this unusual high ratio. | 0 | Theoretical and Fundamental Chemistry |
A phase diagram in physical chemistry, engineering, mineralogy, and materials science is a type of chart used to show conditions (pressure, temperature, volume, etc.) at which thermodynamically distinct phases (such as solid, liquid or gaseous states) occur and coexist at equilibrium. | 0 | Theoretical and Fundamental Chemistry |
Single-wavelength anomalous diffraction (SAD) is a technique used in X-ray crystallography that facilitates the determination of the structure of proteins or other biological macromolecules by allowing the solution of the phase problem. In contrast to multi-wavelength anomalous diffraction (MAD), SAD uses a single dataset at a single appropriate wavelength.
Compared to MAD, SAD has weaker phasing power and requires density modification to resolve phase ambiguity. This downside is not as important as SAD's main advantage: the minimization of time spent in the beam by the crystal, thus reducing potential radiation damage to the molecule while collecting data. SAD also allows a wider choice of heavy atoms and can be conducted without a synchrotron beamline. Today, selenium-SAD is commonly used for experimental phasing due to the development of methods for selenomethionine incorporation into recombinant proteins.
SAD is sometimes called "single-wavelength anomalous dispersion", but no dispersive differences are used in this technique since the data are collected at a single wavelength. | 0 | Theoretical and Fundamental Chemistry |
At low voltages, the rate of migration of the DNA is proportional to the voltage applied, i.e. the higher the voltage, the faster the DNA moves. However, in increasing electric field strength, the mobility of high-molecular-weight DNA fragments increases differentially, and the effective range of separation decreases and resolution therefore is lower at high voltage. For optimal resolution of DNA greater than 2kb in size in standard gel electrophoresis, 5 to 8 V/cm is recommended. Voltage is also limited by the fact that it heats the gel and may cause the gel to melt if a gel is run at high voltage for a prolonged period, particularly for low-melting point agarose gel.
The mobility of DNA however may change in an unsteady field. In a field that is periodically reversed, the mobility of DNA of a particular size may drop significantly at a particular cycling frequency. This phenomenon can result in band inversion whereby larger DNA fragments move faster than smaller ones in PFGE. | 1 | Applied and Interdisciplinary Chemistry |
For a given stress profile and temperature, the point lies in a particular "deformation field". If the values place the point near the center of a field, it is likely that the primary mechanism by which the material will fail, i.e.: the type and rate of failure expected, grain boundary diffusion, plasticity, Nabarro–Herring creep, etc. If however, the stress and temperature conditions place the point near the boundary between two deformation mechanism regions then the dominating mechanism is less clear. Near the boundary of the regimes there can be a combination of mechanisms of deformation occurring simultaneously. Deformation mechanism maps are only as accurate as the number of experiments and calculations undertaken in their creation.
For a given stress and temperature, the strain rate and deformation mechanism of a material is given by a point on the map. By comparing maps of various materials, crystal structures, bonds, grain sizes, etc., studies of these materials properties on plastic flow can be conducted and a more complete understanding of deformation in materials is obtained. | 1 | Applied and Interdisciplinary Chemistry |
Mycoremediation (from ancient Greek (), meaning "fungus", and the suffix , in Latin meaning restoring balance) is a form of bioremediation in which fungi-based remediation methods are used to decontaminate the environment. Fungi have been proven to be a cheap, effective and environmentally sound way for removing a wide array of contaminants from damaged environments or wastewater. These contaminants include heavy metals, organic pollutants, textile dyes, leather tanning chemicals and wastewater, petroleum fuels, polycyclic aromatic hydrocarbons, pharmaceuticals and personal care products, pesticides and herbicides in land, fresh water, and marine environments.
The byproducts of the remediation can be valuable materials themselves, such as enzymes (like laccase), edible or medicinal mushrooms, making the remediation process even more profitable. Some fungi are useful in the biodegradation of contaminants in extremely cold or radioactive environments where traditional remediation methods prove too costly or are unusable. | 1 | Applied and Interdisciplinary Chemistry |
Structural work has determined that its 1,494 Dalton core unit (Glycine / Hydroxy-glycine / FeO) contains iron, but not lithium, leading to the more general term hemoglycin for these molecules. The hemoglycin core contains a total of 22 glycine residues in an anti-parallel beta sheet chain that is terminated at each end by an iron atom plus two oxygens. Four of these glycine residues are oxidized to hydroxy-glycine with hydroxy groups (-OH) on the alpha carbon. This structure was determined by mass spectrometry of meteoritic solvent extracts and has been confirmed in X-ray scattering by crystals of hemoglycin, and also by optical absorption. Crystals show a 480 nm characteristic absorption that can only exist when hydroxy-glycine residues have R chirality and are C-terminal bonded to iron. | 0 | Theoretical and Fundamental Chemistry |
*[http://nanocrystallography.research.pdx.edu/search/edu/ Educational Subset of the Crystallography Open Database (EDU-COD)] (specialization: crystal and molecule structures for college education, access: free, size: medium)
*[https://web.archive.org/web/20070403082355/http://xpdb.nist.gov:8060/BMCD4/ Biological Macromolecule Crystallization Database (BMCD)] (specialization: crystallization of biological macromolecules, access: free, size: medium)
*[http://nanocrystallography.research.pdx.edu/search/cmd/ Crystal Morphology Database (CMD)] (specialization: morphology of crystals, access: free, size: very small)
*[http://www.hypotheticalzeolites.net/DATABASE/DEEM_REFINED/ Database of Hypothetical Structures] (specialization: predicted zeolite-like crystal structures, access: free, size: large)
*[http://www.iza-structure.org/databases/ Database of Zeolite Structures] (specialization: crystal structures of zeolites, access: free, size: small)
*[http://hmofs.northwestern.edu/hc/crystals.php Hypothetical MOFs Database] (specialization: predicted metal-organic framework crystal structures, access: free, size: large)
*[http://www.cryst.ehu.es/icsdb/index.html Incommensurate Structures Database] (specialization: incommensurate structures, access: free, size: small)
*[https://web.archive.org/web/20130515052529/http://www.cinam.univ-mrs.fr/mpcd/ Marseille Protein Crystallization Database (MPCD)] (specialization: crystallization of biological macromolecules, access: free, size: medium)
*[https://web.archive.org/web/20120806204613/http://helios.princeton.edu/mofomics/ MOFomics] (specialization: pore structures of metal-organic frameworks, access: free, size: medium)
*[http://nanocrystallography.research.pdx.edu/search/ncd/ Nano-Crystallography Database (NCD)] (specialization: crystal structures of nanometer sized crystallites, access: free, size: small)
*[https://web.archive.org/web/20120112115407/http://www.nist.gov/srd/nist42.cfm NIST Surface Structure Database] (specialization: surface and interface structures, access: restricted, size: small-medium)
*[http://cod.ibt.lt/pcod/index.html Predicted Crystallography Open Database (PCOD)] (spezialization: predicted crystal structures of organics, metal-organics, metals, alloys, intermetallics, and inorganics, access: free, size: very large)
*[http://www.crystallography.net/tcod/ Theoretical Crystallography Open Database (TCOD)] (spezialization: crystal structures of organics, metal-organics, metals, alloys, intermetallics, and inorganics that were refined or predicted from density functional theory with some experimental input, access: free, size: small)
*[https://web.archive.org/web/20140524081408/http://helios.princeton.edu/zeomics/ ZEOMICS] (specialization: pore structures of zeolites, access: free, size: small) | 0 | Theoretical and Fundamental Chemistry |
A fraction of the input DNA obtained after the sonication step above is labeled with cyanine-5 (Cy5; red) deoxy-cytosine-triphosphate while the methylated DNA, enriched after the immunoprecipitation step, is labeled with cyanine-3 (Cy3; green). The labeled DNA samples are cohybridized on a 2-channel, high-density genomic microarray to probe for presence and relative quantities. The purpose of this comparison is to identify sequences that show significant differences in hybridization levels, thereby confirming the sequence of interest is enriched.
Array-based identification of MeDIP sequences are limited to the array design. As a result, the resolution is restricted to the probes in the array design. There are additional standard steps required in signal processing to correct for hybridization issues such as noise, as is the case with most array technologies.
See for more details. | 1 | Applied and Interdisciplinary Chemistry |
Tris(dimethylamino)aluminium dimer, formally bis(μ-dimethylamino)tetrakis(dimethylamino)dialuminium, is an amide complex of aluminium. This compound may be used as a precursor to other aluminium complexes.
Commercially available, this compound may be prepared from lithium dimethylamide and aluminium trichloride. | 0 | Theoretical and Fundamental Chemistry |
Mitochondria play a central role in many other metabolic tasks, such as:
* Signaling through mitochondrial reactive oxygen species
* Regulation of the membrane potential
* Apoptosis-programmed cell death
* Calcium signaling (including calcium-evoked apoptosis)
* Regulation of cellular metabolism
* Certain heme synthesis reactions (see also: Porphyrin)
* Steroid synthesis
* Hormonal signaling – mitochondria are sensitive and responsive to hormones, in part by the action of mitochondrial estrogen receptors (mtERs). These receptors have been found in various tissues and cell types, including brain and heart
* Immune signaling
* Neuronal mitochondria also contribute to cellular quality control by reporting neuronal status towards microglia through specialised somatic-junctions.
* Mitochondria of developing neurons contribute to intercellular signaling towards microglia, which communication is indispensable for proper regulation of brain development.
Some mitochondrial functions are performed only in specific types of cells. For example, mitochondria in liver cells contain enzymes that allow them to detoxify ammonia, a waste product of protein metabolism. A mutation in the genes regulating any of these functions can result in mitochondrial diseases.
Mitochondrial proteins (proteins transcribed from mitochondrial DNA) vary depending on the tissue and the species. In humans, 615 distinct types of proteins have been identified from cardiac mitochondria, whereas in rats, 940 proteins have been reported. The mitochondrial proteome is thought to be dynamically regulated. | 1 | Applied and Interdisciplinary Chemistry |
An Ellingham diagram is a graph showing the temperature dependence of the stability of compounds. This analysis is usually used to evaluate the ease of reduction of metal oxides and sulfides. These diagrams were first constructed by Harold Ellingham in 1944. In metallurgy, the Ellingham diagram is used to predict the equilibrium temperature between a metal, its oxide, and oxygen — and by extension, reactions of a metal with sulfur, nitrogen, and other non-metals. The diagrams are useful in predicting the conditions under which an ore will be reduced to its metal. The analysis is thermodynamic in nature and ignores reaction kinetics. Thus, processes that are predicted to be favourable by the Ellingham diagram can still be slow. | 1 | Applied and Interdisciplinary Chemistry |
The following are some examples of how DPN is being applied to potential products.
# Biosensor Functionalization – Directly place multiple capture domains on a single biosensor device
# Nanoscale Sensor Fabrication – Small, high-value sensors that can detect multiple targets
# Nanoscale Protein Chips – High-density protein arrays with increased sensitivity | 1 | Applied and Interdisciplinary Chemistry |
The elements that occur on Earth only in traces are listed below.
Isotopes of other elements (not exhaustive):
*Tritium
*Beryllium-7
*Beryllium-10
*Carbon-14
*Fluorine-18
*Sodium-22
*Sodium-24
*Magnesium-28
*Silicon-31
*Silicon-32
*Phosphorus-32
*Sulfur-35
*Sulfur-38
*Chlorine-34m
*Chlorine-36
*Chlorine-38
*Chlorine-39
*Argon-39
*Argon-42
*Calcium-41
*Iron-60
*Nickel-59
*Selenium-79
*Krypton-81
*Strontium-90 | 0 | Theoretical and Fundamental Chemistry |
There have been cases where people died after eating foods containing palytoxin or poisons similar to it. In the Philippines people died after eating Demania crabs. After eating bluestripe herring some people died in Madagascar. People who had eaten smoked mackerel and parrotfish experienced near fatal poisoning in Hawaii and Japan respectively. | 0 | Theoretical and Fundamental Chemistry |
Two populations of cells are cultivated in cell culture. One of the cell populations is fed with growth medium containing normal amino acids. In contrast, the second population is fed with growth medium containing amino acids labeled with stable (non-radioactive) heavy isotopes. For example, the medium can contain arginine labeled with six carbon-13 atoms (C) instead of the normal carbon-12 (C). When the cells are growing in this medium, they incorporate the heavy arginine into all of their proteins. Thereafter, all peptides containing a single arginine are 6 Da heavier than their normal counterparts. Alternatively, uniform labeling with C or N can be used. Proteins from both cell populations are combined and analyzed together by mass spectrometry as pairs of chemically identical peptides of different stable-isotope composition can be differentiated in a mass spectrometer owing to their mass difference. The ratio of peak intensities in the mass spectrum for such peptide pairs reflects the abundance ratio for the two proteins. | 1 | Applied and Interdisciplinary Chemistry |
Herpesviruses are ubiquitous pathogens infecting a variety of animals, including humans. Hosts include many economically important species such as abalone, oysters, salmon, poultry (avian infectious laryngotracheitis, Marek's disease), cattle (bovine malignant catarrhal fever), dogs, goats, horses, cats (feline viral rhinotracheitis), and pigs (pseudorabies). Infections may be severe and may result in fatalities or reduced productivity. Therefore, outbreaks of herpesviruses in livestock cause significant financial losses and are an important area of study in veterinary virology. | 1 | Applied and Interdisciplinary Chemistry |
The endorheic basin lakes are called soda or alkaline lakes when the water inflows contain high concentrations of NaCO. The pH of the soda lake water is generally above 9 and sometimes the salinity is close to brackish water due to depletion of pure water by solar evaporation.
Soda lakes are rich with algal growth due to enhanced availability of dissolved CO in the lake water compared to fresh water or saline water lakes. Sodium carbonate and sodium hydroxide are in equilibrium with availability of dissolved carbon dioxide as given below in the chemical reaction
* NaCO + HO
* NaHCO
During day time when sun light is available, Algae undergoes photosynthesis process which absorbs CO to shift the reaction towards NaOH formation and vice versa takes place during night time with the release of CO from the respiration process of Algae towards NaCO and NaHCO formation. In soda lake waters, carbonates of sodium act as catalyst for the algae growth by providing favourable higher concentration of dissolved CO during the day time. Due to fluctuation in dissolved CO, the pH and alkalinity of the water also keep varying. | 0 | Theoretical and Fundamental Chemistry |
Sulfonyl halides have tetrahedral sulfur centres attached to two oxygen atoms, an organic radical, and a halide. In a representative example, methanesulfonyl chloride, the S=O, S−C, and S−Cl bond distances are respectively 142.4, 176.3, and 204.6 pm. | 0 | Theoretical and Fundamental Chemistry |
* Analytical and numerical methods in FSI.
* Techniques for laboratory and in-service investigations.
* Stochastic methods.
* Hydroelasticity-based prediction of Wave Loads and Responses.
* Impact, sloshing and shock.
* Flow induced vibration (FIV).
* Tsunami and seaquake induced responses of large marine structures.
* Devices for energy extraction. | 1 | Applied and Interdisciplinary Chemistry |
For the reasons cited above, in recent years stream channelization has been greatly curtailed in the U.S., and in some instances even partially reversed. In 1990 the United States Government published a "no net loss of wetlands" policy, whereby a stream channelization project in one place must be offset by the creation of new wetlands in another, a process known as "mitigation."
The major agency involved in the enforcement of this policy is the same Army Corps of Engineers, which for many years was the primary promoter of wide-scale channelization. Often, in the instances where channelization is permitted, boulders may be installed in the bed of the new channel so that water velocity is slowed, and channels may be deliberately curved as well. In 1990 the U.S. Congress gave the Army Corps a specific mandate to include environmental protection in its mission, and in 1996 it authorized the Corps to undertake restoration projects. The U.S. Clean Water Act regulates certain aspects of channelization by requiring non-Federal entities (i.e. state and local governments, private parties) to obtain permits for dredging and filling operations. Permits are issued by the Army Corps with EPA participation. | 1 | Applied and Interdisciplinary Chemistry |
Max Jaffe was a distinguished 19th-century German biochemist, pathologist, pharmacologist, and professor. He was born on July 25, 1841, in what was formerly Grünberg, Silesia and is now Zielona Góra, Poland. While attending medical school at the University of Berlin, he studied under Ludwig Traube and Wilhelm Kühne. Afterward, he worked as an assistant in a medical clinic in Königsberg. There, he co-authored a paper on putrid sputum with Ernst Viktor von Leyden that led to the discovery of certain characteristic putrid processes in the lungs. After earning his degree in internal medicine, he served in the Franco-Prussian War and was decorated with the Iron Cross Second Class. The title of Extraordinary Professor of Medicinal Chemistry was awarded to him in 1872 and the following year he became the first Ordinary Professor of Pharmacology at the University of Königsberg. He was promoted to director of the Laboratory for Medical Chemistry and Experimental Pharmacology in 1878 and became a member of the Deutsche Akademie der Naturforscher Leopoldina in 1882. Aside from studying creatinine, he is also known for discovering urobilin and urobilinogen in urine and found that these compounds originated in bile. He died on October 26, 1911, in Berlin and is buried in the Weißensee Cemetery. | 1 | Applied and Interdisciplinary Chemistry |
N-methylhistamine (NMH), also known as 1-methylhistamine, is a product of N-methylation of histamine in a reaction catalyzed by the HNMT enzyme.
NMH is considered a biologically inactive metabolite of histamine. NMH is excreted in the urine and can be measured to estimate the amounts of active histamine in the body. While NMH has some biological activity on its own, it is much weaker than histamine. NMH can bind to histamine receptors but has a lower affinity and efficacy than histamine for these receptors, meaning that it binds less strongly and activates them less effectively. Depending on the receptor subtype and the tissue context, NMH may act as a partial agonist or an antagonist for some histamine receptors. NMH may have some modulatory effects on histamine signaling, but it is unlikely to cause significant allergic or inflammatory reactions by itself. NMH may also serve as a feedback mechanism to regulate histamine levels and prevent excessive histamine release. Still, NMT, being a product in a reaction catalyzed by HNMT, may inhibit expression of HNMT in a negative feedback loop.
Urinary NMH can be measured in clinical settings when systemic mastocytosis is suspected. Systemic mastocytosis and anaphylaxis are typically associated with at least a two-fold increase in urinary NMH levels, which are also increased in patients taking monoamine oxidase inhibitors and in patients on histamine-rich diets. | 1 | Applied and Interdisciplinary Chemistry |
The mound system was designed in the 1930s by the North Dakota College of Agriculture. and was known as the Nodak Disposal System. In 1976, the University of Wisconsin studied the design of mound systems as part of the university's Waste Management Project. This project published the first ever design manual for identifying the appropriate site conditions and design criteria for mounds. In 2000, a new manual was released. | 1 | Applied and Interdisciplinary Chemistry |
Drug targets are the specific sites where a medication carries out its pharmacological activity. The interaction between the drug and this site results in a modification of the target that may include inhibition or potentiation. Most of the pharmacogenetic interactions that involve drug targets are within the field of oncology and include targeted therapeutics designed to address somatic mutations (see also Cancer Pharmacogenomics). For example, EGFR inhibitors like gefitinib (Iressa) or erlotinib (Tarceva) are only indicated in patients carrying specific mutations to EGFR.
Germline mutations in drug targets can also influence response to medications, though this is an emerging subfield within pharmacogenomics. One well-established gene-drug interaction involving a germline mutation to a drug target is warfarin (Coumadin) and VKORC1, which codes for vitamin K epoxide reductase (VKOR). Warfarin binds to and inhibits VKOR, which is an important enzyme in the vitamin K cycle. Inhibition of VKOR prevents reduction of vitamin K, which is a cofactor required in the formation of coagulation factors II, VII, IX and X, and inhibitors protein C and S. | 1 | Applied and Interdisciplinary Chemistry |
SedDB was created as an online data management and information system for sediment geochemistry.
SedDB is based on a relational database that contains the full range of analytical values for sediment samples, primarily from marine sediment cores, including major and trace element concentrations, radiogenic and stable isotope ratios, and data for all types of material such as organic and inorganic components, leachates, and size fractions. SedDB also archives a vast array of metadata relating to the individual sample. Examples of Seddb metadata are: sample latitude and longitude; elevation below sea surface; material analyzed; analytical methodology; analytical precision and reference standard measurements. As of April, 2013 SedDB contains nearly 750,000 individual analytical data points of 104,000 samples. SedDB contents have been migrated to [http://portal.earthchem.org/ The EarthChem Portal]. | 0 | Theoretical and Fundamental Chemistry |
In the Burke–Schumann limit, . Then the equation reduces to
An approximate solution to this equation was developed by Liñán himself using integral method in 1963 for his thesis,
where is the error function and
Here is the location where reaches its minimum value . When , , and . | 1 | Applied and Interdisciplinary Chemistry |
In biochemistry, docosanoids are signaling molecules made by the metabolism of twenty-two-carbon fatty acids (EFAs), especially the omega-3 fatty acid, docosahexaenoic acid (DHA) (i.e. 4Z,7Z,10Z,13Z,16Z,19Z-docosahexaenoic acid) by lipoxygenase, cyclooxygenase, and cytochrome P450 enzymes. Other docosanoids are metabolites of n-3 docosapentaenoic acid (DPA) (i.e. 7Z,10Z,13Z,16Z,19Z-docosapentaenoic acid, or clupanodonic acid), n-6 DPA (i.e. 4Z,7Z,10Z,13Z,16Z-docosapentaenoic acid, or osbond acid), and docosatetraenoic acid (i.e. 7Z,10Z,13Z,16Z-docosatetraenoic acid, DTA, or adrenic acid). Prominent docosanoid metabolites of DPA and n-3 DHA are members of the specialized pro-resolving mediators class of polyunsaturated fatty acid metabolites that possess potent anti-inflammation, tissue healing, and other activities. | 1 | Applied and Interdisciplinary Chemistry |
Analogous to sulfamic acid (HNSO) and as is the case generally for amino acids, HOSA exists in the solid state as a zwitterion: HNOSO. It resembles an ammonia molecule coordinate covalently bonded to a sulfate group. | 0 | Theoretical and Fundamental Chemistry |
Mostafa A. El-Sayed (Arabic: مصطفى السيد) is an Egyptian-American physical chemist, nanoscience researcher, member of the National Academy of Sciences and US National Medal of Science laureate. He is known for the spectroscopy rule named after him, the El-Sayed rule. | 1 | Applied and Interdisciplinary Chemistry |
Since irradiation increases with proximity to the source of radiation, and as it is impossible to distance or shield an internal source, radioactive materials inside the body can deliver much higher doses to the host organs than they normally would from outside the body. This is particularly true for alpha and beta emitters that are easily shielded by skin and clothing. Some have hypothesized that alphas high relative biological effectiveness might be attributable to cells tendency to absorb transuranic metals into the cellular nucleus where they would be in very close proximity to the genome, though an elevated effectiveness can also be observed for external alpha radiation in cellular studies. As in the calculations for equivalent dose and effective dose, committed dose must include corrections for the relative biological effectiveness of the radiation type and weightings for tissue sensitivity. | 0 | Theoretical and Fundamental Chemistry |
Beta decay is characterized by the emission of a neutrino and a negatron which is equivalent to an electron. This process occurs when a nucleus has an excess of neutrons with respect to protons, as compared to the stable isobar. This type of transition converts a neutron into a proton; similarly, a positron is released when a proton is converted into a neutron. These decays follows the relation:
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The energy of photons (, which includes Planck's constant) emitted when electrons incident on a substance using an electron beam with a constant energy () relax to a lower energy unoccupied state () is given by the conservation of energy as:
By measuring and , the unoccupied state () of the surface can be found. | 0 | Theoretical and Fundamental Chemistry |
In these types of reactions, CO is released as the phosphaethynolate anion acts as either a mild nucleophilic source of phosphorus or a Brønsted base. Examples of these types of reactions involving PCO include work conducted by Grutzmacher and Goicoechea.
In 2014, Grutzmacher et al. reported that an imidazolium salt would react with the phosphaethynolate anion to produce a phosphinidine carbene adduct. Computational mechanistic studies were conducted on this reaction using density functional theory at the B3LYP/6-31+G* level. The results of these investigations suggested that the lowest energy and therefore most likely pathway involves PCO acting as a Brønsted base initially deprotonating the acidic imidazolium cation to generate the intermediate phosphaketene, HPCO. The highly unstable protonated PCO remains hydrogen bonded to the newly produced N-heterocylic carbene prior to rearrangement and formation of the observed product. In this case, PCO does not act as a mild nucleophile due to the augmented stability of the starting imidazolium cation.
On the other hand, in the work published by Goicoechea and co-workers in 2015, the phosphaethynolate anion can be seen to act as a source of nucleophilic phosphide (). The anion was seen to add across the double bond of cyclotrisilene thus introducing a phosphorus vertex into its scaffold (after undergoing decarbonylation). | 0 | Theoretical and Fundamental Chemistry |
In the early 1970s, the traditional blast furnace and sinter plant technology that was the mainstay of the lead smelting industry was coming under sustained pressure from more stringent environmental requirements, increased energy costs, decreasing metal prices and rising capital and operating costs.
Many smelting companies were seeking new processes to replace sinter plants and blast furnaces. Possibilities included the QSL lead smelting process, the Kivcet process, the Kaldo top-blown rotary converter, and adapting Outokumpu's successful copper and nickel flash furnace to lead smelting.
MIM was seeking ways to safeguard the future of its Mount Isa lead smelting operations. It did this in two ways:
# working to improve the environmental and operational performance of its existing operations
# investigating new technologies.
MIM investigated new technologies by arranging plant testing of large parcels of Mount Isa lead concentrates for all the then process options except for the Kivcet process. At the same time, it had been aware of the use of top-jetting lances in the Mitsubishi and Kaldo processes, and of top-entry submerged combustion lance investigations undertaken by Asarco (which had a long association with MIM, including being a shareholder in MIM Holdings) in the 1960s. This stimulated MIM's interest in the Sirosmelt lance, which was seen as a way to produce a robust submerged lance.
Following the copper slag trials of 1976–1978, MIM initiated a joint project with the CSIRO in 1978 to investigate the possibility of applying Sirosmelt lances to lead smelting.
The work began with computer modelling the equilibrium thermodynamics (1978) and was followed by laboratory bench-scale test work using large alumina silicate crucibles (1978–1979). The results were sufficiently encouraging that MIM built a 120 kg/h test rig in Mount Isa. It began operation in September 1980. This was used to develop a two-stage process to produce lead bullion from Mount Isa lead concentrate. The first stage was an oxidation step that removed virtually all the sulfur from the feed, oxidising the contained lead to lead oxide (PbO) that was largely collected in the slag (some was carried out of the furnace as lead oxide fume that was returned for lead recovery). The second stage was a reduction step in which the oxygen was removed from the lead to form lead metal. | 1 | Applied and Interdisciplinary Chemistry |
The Kirkendall effect was discovered by Ernest Kirkendall and Alice Smigelskas in 1947, in the course of Kirkendalls ongoing research into diffusion in brass. The paper in which he discovered the famous effect was the third in his series of papers on brass diffusion, the first being his thesis. His second paper revealed that zinc diffused more quickly than copper in alpha-brass, which led to the research producing his revolutionary theory. Until this point, substitutional and ring methods were the dominant ideas for diffusional motion. Kirkendalls experiment produced evidence of a vacancy diffusion mechanism, which is the accepted mechanism to this day. At the time it was submitted, the paper and Kirkendalls ideas were rejected from publication by Robert Franklin Mehl, director of the Metals Research Laboratory at Carnegie Institute of Technology (now Carnegie Mellon University). Mehl refused to accept Kirkendalls evidence of this new diffusion mechanism, and denied publication for over six months, only relenting after a conference was held and several other researchers confirmed Kirkendall's results. | 1 | Applied and Interdisciplinary Chemistry |
Radioactive tracer compounds, radiopharmaceuticals, are used to observe the function of various organs and body systems. These compounds use a chemical tracer which is attracted to or concentrated by the activity which is being studied. That chemical tracer incorporates a short lived radioactive isotope, usually one which emits a gamma ray which is energetic enough to travel through the body and be captured outside by a gamma camera to map the concentrations. Gamma cameras and other similar detectors are highly efficient, and the tracer compounds are generally very effective at concentrating at the areas of interest, so the total amounts of radioactive material needed are very small.
The metastable nuclear isomer technetium-99m is a gamma-ray emitter widely used for medical diagnostics because it has a short half-life of 6 hours, but can be easily made in the hospital using a technetium-99m generator. Weekly global demand for the parent isotope molybdenum-99 was in 2010, overwhelmingly provided by fission of uranium-235. | 0 | Theoretical and Fundamental Chemistry |
When a solute forms a saturated solution in a solvent, the concentration of the solute, at a given temperature, is determined by the equilibrium constant at that temperature.
The activity of a pure substance in the solid state is one, by definition, so the expression simplifies to
If the solute does not dissociate the summation is replaced by a single term, but if dissociation occurs, as with ionic substances
For example, with NaSO, and so the solubility product is written as
Concentrations, indicated by [...], are usually used in place of activities, but activity must be taken into account of the presence of another salt with no ions in common, the so-called salt effect. When another salt is present that has an ion in common, the common-ion effect comes into play, reducing the solubility of the primary solute. | 0 | Theoretical and Fundamental Chemistry |
In parallel with this work, the Cell was tested for the recovery of fine coal at the Newlands coal mine, also owned by MIM Holdings Limited. This fines stream was cyclone overflow, which contained 15–50% ash and was previously discarded. The particle size of this stream was less than 25 μm. Pilot plant testing showed that it was possible to achieve greater than 90% recovery of coal, with less than 10% ash in the product.
Subsequently, a full-scale plant was commissioned at Newlands in the 1988–89 financial year, with six rectangular Cells (1.5 m × 3.5 m) installed in a two-stage arrangement. The cells in the first stage had seven downcomers, while those in the second had six.
These cells were in continuous operation at Newlands for 15 years until a new washing plant was built to replace the old one in 2006.
Two additional Cells were installed at MIM Holdings' Collinsville Coal operations in 1990. These had 10 downcomers each. | 1 | Applied and Interdisciplinary Chemistry |
Ketogenesis may or may not occur, depending on levels of available carbohydrates in the cell or body. This is closely related to the paths of acetyl-CoA:
* When the body has ample carbohydrates available as energy source, glucose is completely oxidized to CO; acetyl-CoA is formed as an intermediate in this process, first entering the citric acid cycle followed by complete conversion of its chemical energy to ATP in oxidative phosphorylation.
* When the body has excess carbohydrates available, some glucose is fully metabolized, and some of it is stored in the form of glycogen or, upon citrate excess, as fatty acids (see lipogenesis). Coenzyme A is recycled at this step.
* When the body has no free carbohydrates available, fat must be broken down into acetyl-CoA in order to get energy. Under these conditions, acetyl-CoA cannot be metabolized through the citric acid cycle because the citric acid cycle intermediates (mainly oxaloacetate) have been depleted to feed the gluconeogenesis pathway. The resulting accumulation of acetyl-CoA activates ketogenesis.
Insulin and glucagon are key regulating hormones of ketogenesis, with insulin being the primary regulator. Both hormones regulate hormone-sensitive lipase and acetyl-CoA carboxylase. Hormone-sensitive lipase produces diglycerides from triglycerides, freeing a fatty acid molecule for oxidation. Acetyl-CoA carboxylase catalyzes the production of malonyl-CoA from acetyl-CoA. Malonyl-CoA reduces the activity of carnitine palmitoyltransferase I, an enzyme that brings fatty acids into the mitochondria for β-oxidation. Insulin inhibits hormone-sensitive lipase and activates acetyl-CoA carboxylase, thereby reducing the amount of starting materials for fatty acid oxidation and inhibiting their capacity to enter the mitochondria. Glucagon activates hormone-sensitive lipase and inhibits acetyl-CoA carboxylase, thereby stimulating ketone body production, and making passage into the mitochondria for β-oxidation easier. Insulin also inhibits HMG-CoA lyase, further inhibiting ketone body production. Similarly, cortisol, catecholamines, epinephrine, norepinephrine, and thyroid hormones can increase the amount of ketone bodies produced, by activating lipolysis (the mobilization of fatty acids out of fat tissue) and thereby increasing the concentration of fatty acids available for β-oxidation. Unlike glucagon, catecholamines are capable of inducing lipolysis even in the presence of insulin for use by peripheral tissues during acute stress.
Peroxisome Proliferator Activated Receptor alpha (PPARα) also has the ability to upregulate ketogenesis, as it has some control over a number of genes involved in ketogenesis. For example, monocarboxylate transporter 1, which is involved in transporting ketone bodies over membranes (including the blood–brain barrier), is regulated by PPARα, thus affecting ketone body transportation into the brain. Carnitine palmitoyltransferase is also upregulated by PPARα, which can affect fatty acid transportation into the mitochondria. | 1 | Applied and Interdisciplinary Chemistry |
Between 1902 and 1908, carbon tetrachloride-based fire extinguishers began to appear in the United States, years after Europe.
In 1910, the Pyrene Manufacturing Company of Delaware filed a patent to use carbon tetrachloride to extinguish fires. The liquid was vaporized by the heat of combustion and extinguished flames, an early form of gaseous fire suppression. At the time it was believed the gas displaced oxygen in the area near the fire, but later research found that the gas inhibited the chemical chain reaction of the combustion process.
In 1911, Pyrene patented a small, portable extinguisher that used the chemical. The extinguisher consisted of a brass bottle with an integrated hand-pump that was used to expel a jet of liquid toward the fire. As the container was unpressurized, it could easily be refilled after use. Carbon tetrachloride was suitable for liquid and electrical fires and the extinguishers were often carried on aircraft or motor vehicles. However, as early as 1920, there were reports of fatalities caused by the chemical when used to fight a fire in a confined space.
In the first half of the 20th century, another common fire extinguisher was a single-use, sealed glass globe, a "fire grenade, " filled with carbon tetrachloride or salt water. The bulb could be thrown at the base of the flames to quench the fire. The carbon tetrachloride type could also be installed in a spring-loaded wall fixture with a solder-based restraint. When the solder melted by high heat, the spring would either break the globe or launch it out of the bracket, allowing the extinguishing agent to be automatically dispersed into the fire.
A well-known brand of fire grenade was the "Red Comet", which was variously manufactured with other fire-fighting equipment in the Denver, Colorado area by the Red Comet Manufacturing Company from its founding in 1919 until manufacturing operations were closed in the early 1980s.
Since carbon tetrachloride freezes at –23 °C, the fire extinguishers would contain only 89-90% carbon tetrachloride and 10% trichloroethylene (m.p. –85 °C) or chloroform (m.p. –63 °C) for lowering the extinguishing mixture's freezing point down to temperatures as low as –45 °C. The extinguishers with 10% trichloroethylene would contain 1% carbon disulfide as a stabiliser. | 1 | Applied and Interdisciplinary Chemistry |
* No external power sources required.
* Relatively easy to install.
* Lower voltages and current mean that risk of causing stray current interference on other structures is low.
* Require less frequent monitoring than impressed current CP systems.
* Relatively low risk of overprotection.
* Once installed, testing the system components is relatively simple for trained personnel. | 0 | Theoretical and Fundamental Chemistry |
In a cyclic voltammetry experiment carried out with an adsorbed redox protein, the oxidation and reduction of each redox site shows as a pair of positive and negative peaks. Since all the sample is oxidised or reduced during the potential sweep, the peak current and peak area should be proportional to scan rate (observing that the peak current is proportional to scan rate proves that the redox species that gives the peak is actually immobilised). The same is true for experiments performed with non-biological redox molecules adsorbed onto electrodes. The theory was mainly developed by the French electrochemist Etienne Laviron in the 1980s.
Since both this faradaic current (which results from the oxidation/reduction of the adsorbed molecule) and the capacitive current (which results from electrode charging) increase in proportion to scan rate, the peaks should remain visible when the scan rate is increased. In contrast, when the redox analyte is in solution and diffuses to/from the electrode, the peak current is proportional to the square root of the scan rate (see: Randles–Sevcik equation). | 0 | Theoretical and Fundamental Chemistry |
The aims of nonclinical safety pharmacology evaluations are three-fold:
* To protect Phase I clinical trial volunteers from acute adverse effects of drugs
* To protect patients (including patients participating in Phase II and III clinical trials)
* To minimize risks of failure during drug development and post-marketing phases due to undesirable pharmacodynamic effects | 1 | Applied and Interdisciplinary Chemistry |
In a cylindrical pipe of uniform diameter , flowing full, the pressure loss due to viscous effects is proportional to length and can be characterized by the Darcy–Weisbach equation:
where the pressure loss per unit length (SI units: Pa/m) is a function of:
: , the density of the fluid (kg/m);
: , the hydraulic diameter of the pipe (for a pipe of circular section, this equals ; otherwise for a pipe of cross-sectional area and perimeter ) (m);
: , the mean flow velocity, experimentally measured as the volumetric flow rate per unit cross-sectional wetted area (m/s);
: , the Darcy friction factor (also called flow coefficient ).
For laminar flow in a circular pipe of diameter , the friction factor is inversely proportional to the Reynolds number alone () which itself can be expressed in terms of easily measured or published physical quantities (see section below). Making this substitution the Darcy–Weisbach equation is rewritten as
where
: is the dynamic viscosity of the fluid (Pa·s = N·s/m = kg/(m·s));
: is the volumetric flow rate, used here to measure flow instead of mean velocity according to (m/s).
Note that this laminar form of Darcy–Weisbach is equivalent to the Hagen–Poiseuille equation, which is analytically derived from the Navier–Stokes equations. | 1 | Applied and Interdisciplinary Chemistry |
Novosibirsk Chemical Engineering Technical School named after D. I. Mendeleev () is an educational institution founded in 1929. The school is located between Nizhegorodskaya, Sacco and Vanzetti and Sadovaya streets in Oktyabrsky City District of Novosibirsk, Russia. | 1 | Applied and Interdisciplinary Chemistry |
Compounds possessing a methylene bridge located between two strong electron withdrawing groups (such as nitro, carbonyl or nitrile groups) are sometimes called active methylene compounds. Treatment of these with strong bases can form enolates or carbanions, which are often used in organic synthesis. Examples include the Knoevenagel condensation and the malonic ester synthesis. | 0 | Theoretical and Fundamental Chemistry |
The main advantage of electroforming is that it accurately replicates the external shape of the mandrel. Generally, machining a cavity accurately is more challenging than machining a convex shape, however the opposite holds true for electroforming because the mandrel's exterior can be accurately machined and then used to electroform a precision cavity.
Compared to other basic metal forming processes (casting, forging, stamping, deep drawing, machining and fabricating) electroforming is very effective when requirements call for extreme tolerances, complexity or light weight. The precision and resolution inherent in the photo-lithographically produced conductive patterned substrate, allows finer geometries to be produced to tighter tolerances while maintaining superior edge definition with a near optical finish. Electroformed metal can be extremely pure, with superior properties over wrought metal due to its refined crystal structure. Multiple layers of electroformed metals can be bonded together, or to different substrate materials to produce complex structures with "grown-on" flanges and bosses.
Tolerances of 1.5 to 3 nanometres have been reported.
A wide variety of shapes and sizes can be made by electroforming, the principal limitation being the need to part the product from the mandrel. Since the fabrication of a product requires only a single model or mandrel, low production quantities can be made economically. | 1 | Applied and Interdisciplinary Chemistry |
Enzymes and receptors that contain thiol or sulfhydryl functional groups are actively targeted by arsenite (III) metabolites. These sulfur-containing compounds are normally glutathione and the amino acid cysteine. Arsenite derivatives generally have higher binding affinity compared to the arsenate metabolites. These bindings restrict activity of certain metabolic pathways. For example, pyruvate dehydrogenase (PDH) is inhibited when monomethylarsonous acid (MMA) targets the thiol group of the lipoic acid cofactor. PDH is a precursor of acetyl-CoA, thus the inhibition of PDH eventually limits the production of ATP in electron transport chain, as well as the production of gluconeogenesis intermediates. | 1 | Applied and Interdisciplinary Chemistry |
Conradson carbon residue, commonly known as "Concarbon" or "CCR", is a laboratory test used to provide an indication of the coke-forming tendencies of an oil. Quantitatively, the test measures the amount of carbonaceous residue remaining after the oil's evaporation and pyrolysis. In general, the test is applicable to petroleum products which are relatively non-volatile, and which decompose on distillation at atmospheric pressure. The phrase "Conradson carbon residue" and its common names can refer to either the test or the numerical value obtained from it. | 0 | Theoretical and Fundamental Chemistry |
An exercise mimetic is a drug that mimics some of the biological effects of physical exercise. Exercise is known to have an effect in preventing, treating, or ameliorating the effects of a variety of serious illnesses, including cancer, type 2 diabetes, cardiovascular disease, and psychiatric and neurological diseases such as Alzheimer's disease. As of 2021, no drug is known to have the same benefits.
Known biological targets affected by exercise have also been targets of drug discovery, with limited results. These known targets include:
The majority of the effect of exercise in reducing cardiovascular and all-cause mortality cannot be explained via improvements in quantifiable risk factors, such as blood cholesterol. This further increases the challenge of developing an effective exercise mimetic. Moreover, even if a broad spectrum exercise mimetic were invented, it is not necessarily the case that its public health effects would be superior to interventions to increase exercise in the population. | 1 | Applied and Interdisciplinary Chemistry |
A microchannel plate is a slab made from resistive material (most often glass) 0.5 to 2mm thick with a regular array of tiny tubes (microchannels) leading from one face to the other. The microchannels are typically 5-20 micrometers in diameter, parallel to each other and enter the plate at a small angle to the surface (8-13° from normal). Plates are often round disks, but can be cut to any shape from sizes 10mm up to 200mm. They may also be curved. | 0 | Theoretical and Fundamental Chemistry |
Many enzymatic systems need Mn to function, but in high levels, Mn can become toxic. One environmental reason Mn levels can increase in seawater is when hypoxic periods occur. Since 1990 there have been reports of Mn accumulation in marine organisms including fish, crustaceans, mollusks, and echinoderms. Specific tissues are targets in different species, including the gills, brain, blood, kidney, and liver/hepatopancreas. Physiological effects have been reported in these species. Mn can affect the renewal of immunocytes and their functionality, such as phagocytosis and activation of pro-phenoloxidase, suppressing the organisms' immune systems. This causes the organisms to be more susceptible to infections. As climate change occurs, pathogen distributions increase, and in order for organisms to survive and defend themselves against these pathogens, they need a healthy, strong immune system. If their systems are compromised from high Mn levels, they will not be able to fight off these pathogens and die. | 1 | Applied and Interdisciplinary Chemistry |
For faster reactions, the time required to mix the reactants and bring them to a specified temperature may be comparable or longer than the half-life of the reaction. Special methods to start fast reactions without slow mixing step include
* Stopped flow methods, which can reduce the mixing time to the order of a millisecond The stopped flow methods have limitation, for example, we need to consider the time it takes to mix gases or solutions and are not suitable if the half-life is less than about a hundredth of a second.
* Chemical relaxation methods such as temperature jump and pressure jump, in which a pre-mixed system initially at equilibrium is perturbed by rapid heating or depressurization so that it is no longer at equilibrium, and the relaxation back to equilibrium is observed. For example, this method has been used to study the neutralization HO + OH with a half-life of 1 μs or less under ordinary conditions.
* Flash photolysis, in which a laser pulse produces highly excited species such as free radicals, whose reactions are then studied. | 0 | Theoretical and Fundamental Chemistry |
The Anglo-Scandinavian Cardiac Outcomes Trial-Blood Pressure Lowering Arm (ASCOT-BLA) was a 2005 landmark trial that compared the effects of the established therapy of the combination of atenolol and bendroflumethiazide to the new drug combination of amlodipine and perindopril (trade names Viacoram, AceryCal etc.). The study of more than 19 000 patients world-wide was terminated earlier than anticipated because it clearly demonstrated a statistically significant improvement in mortality and cardiovascular outcomes with the newer treatment. The combination of amlodipine and perindopril remains in the current treatment guidelines for hypertension and the outcomes of the ASCOT-BLA trial paved the way for further research into combination therapy and newer agents. | 0 | Theoretical and Fundamental Chemistry |
Pollution of the Hudson River is largely due to dumping of PCBs by General Electric from 1947 to 1977. GE dumped an estimated 1.3 million pounds of PCBs into the Hudson River during these years. The PCBs came from the company's two capacitor manufacturing plants at Hudson Falls and Fort Edward, New York. This pollution caused a range of harmful effects to wildlife and people who eat fish from the river or drink the water. In 1984, EPA declared a 200-mile (320 km) stretch of the river, from Hudson Falls to New York City, to be a Superfund site requiring cleanup. Extensive remediation actions on the river began in the 1970s with the implementation of wastewater discharge permits and consequent control or reduction of wastewater discharges, and sediment removal operations, which have continued into the 21st century.
Love Canal is a neighborhood in Niagara Falls, New York, that was heavily contaminated with toxic waste including PCBs. Eighteen Mile Creek in Lockport, New York, is an EPA Superfund site for PCBs contamination.
PCB pollution at the State Office Building in Binghamton was responsible for what is now considered to be the first indoor environmental disaster in the United States. In 1981, a transformer explosion in the basement spewed PCBs throughout the entire 18-story building. The contamination was so severe that cleanup efforts kept the building closed for 13 years. | 1 | Applied and Interdisciplinary Chemistry |
PFASs play a key economic role for companies such as DuPont, 3M, and W. L. Gore & Associates because they are used in emulsion polymerization to produce fluoropolymers. They have two main markets: a $1 billion annual market for use in stain repellents, and a $100 million annual market for use in polishes, paints, and coatings. In 2022, 3M announced that it would end PFAS production by 2025. | 0 | Theoretical and Fundamental Chemistry |
Because hemoglycin has now been found to be the dominant polymer of amino acids in 6 different meteorites (Allende, Acfer 086, , Kaba, Orgueil and Sutter's Mill), each time with the same structure, it has been proposed that it is produced by a process of template replication. The measured 480 nm absorbance is larger than expected for a racemic distribution of R and S chirality in the hydroxy-glycine residues, indicating an R chirality excess in the polymer. Modeling of template replication that is assumed to depend on 480 nm absorption leads to an excess of R chirality and thus is consistent with this finding. | 0 | Theoretical and Fundamental Chemistry |
The first recorded experimental work in copper was conducted by Cushing in 1894 in order to demonstrate that copper plate found in Hopewell mounds in Ohio could have been produced by the Hopewell people and not come from European trade. In his experiments, Cushing used antler and stone tools to cut out sheets of copper and puncture round holes in them through a method of pressure and grinding. In addition to the copper sheet experiments, Cushing also conducted smelting experiments reconstructed from finding at Salado Valley, Arizona pueblo excavations to reproduce copper artifacts. | 1 | Applied and Interdisciplinary Chemistry |
Black, or amorphous arsenic (chemical formula As) is synthesized first through the sublimation of gray arsenic followed by condensation onto a heated surface. This structure is thought to be the arsenic analogue of red phosphorus. The structure of black arsenic in its crystalline phase, while not synthesized in its pure form, is by extension analogous to black phosphorus, and takes on an orthorhombic structure built from As rings. Black arsenic has as-yet been synthesized only in the presence of atomic impurities including mercury,
phosphorus, and oxygen, though a pure form of black arsenic was found in the Copiapó region of Chile. Mechanical exfoliation of the mineral found in Chilean caves, arsenolamprite, revealed a molecular structure with high in-phase anisotropy and potential as a semiconducting material. | 0 | Theoretical and Fundamental Chemistry |
Desmodium also controls the parasitic weed, Striga, resulting in significant yield increases of about 2 tonnes/hectare (0.9 short tons per acre) per cropping season. In addition to benefits derived from increased nitrogen availability and competition for light, it was found that D. uncinatum strongly suppresses striga growth through allelopathy. These effects are thought to be related to isoflavanones produced in Desmodium roots, which can either promote the germination of striga seeds or inhibit seedling growth, depending on their structure. Together, these effects result in the phenomenon known as "suicidal germination", thus reducing the striga seed bank in the soil. Other Desmodium species have also been evaluated and have similar effects on stemborers and striga weed and are currently being used as intercrops in maize, sorghum and millets. | 1 | Applied and Interdisciplinary Chemistry |
The usage of multiple reading frames leads to the possibility of overlapping genes; there may be many of these in viral, prokaryote, and mitochondrial genomes. Some viruses, e.g. hepatitis B virus and BYDV, use several overlapping genes in different reading frames.
In rare cases, a ribosome may shift from one frame to another during translation of an mRNA (translational frameshift). This causes the first part of the mRNA to be translated in one reading frame, and the latter part to be translated in a different reading frame. This is distinct from a frameshift mutation, as the nucleotide sequence (DNA or RNA) is not altered—only the frame in which it is read. | 1 | Applied and Interdisciplinary Chemistry |
The Federation of Analytical Chemistry and Spectroscopy Societies or FACSS is a scientific society incorporated on June 28, 1972, with the goal of promoting research and education in analytical chemistry. The organization combined the many smaller meetings of the individual societies into an annual meeting that includes all of analytical chemistry. The meetings are intended to provide a forum for scientists to address the development of analytical chemistry, chromatography, and spectroscopy.
The society's main activity is its annual conference held every fall. These conference offer plenary sessions, workshops, job fairs, oral presentations, poster presentations, and conference networking events. The conference was held internationally for the first time in 1999 when it was hosted in Vancouver, BC. The annual conference is often discussed in the journal Applied Spectroscopy, Spectroscopy Magazine, and American Pharmaceutical Reviews.
At the 2011 FACSS Conference in Reno, NV, the FACSS organization changed the name of the annual conference to SciX. The first [http://scixconference.org/ SciX Conference] presented by FACSS was held in Kansas City, MO in 2012. The name change was discussed in Spectroscopy in fall 2011:
[https://archive.today/20130123212653/http://spectroscopyonline.findanalytichem.com/spectroscopy/article/articleDetail.jsp?id=744507]
[http://blogs.rsc.org/ja/2011/10/27/facss-names-their-annual-scientific-conference-scix/]. More information about the new name can be found at scixconference.org | 0 | Theoretical and Fundamental Chemistry |
His group has also been involved in the development of a novel technique: Laser Vaporization Controlled Condensation (LVCC) for the synthesis of a variety of semiconductor, metal and metal oxide nanoparticles. His research lab is currently focused on the applications of graphene in heterogeneous catalysis and energy conversion, and he developed novel microwave and laser methods for the synthesis of nanoparticle catalysts supported on graphene. The recent discovery of efficient photo-thermal energy conversion by graphene-based materials by El-Shall's group has resulted in the development of new materials for efficient solar water desalination and the removal of heavy metals from contaminated water. | 0 | Theoretical and Fundamental Chemistry |
Glow discharges can be used to analyze the elemental, and sometimes molecular, composition of solids, liquids, and gases, but elemental analysis of solids is the most common. In this arrangement, the sample is used as the cathode. As mentioned earlier, gas ions and atoms striking the sample surface knock atoms off of it, a process known as sputtering.
The sputtered atoms, now in the gas phase, can be detected by atomic absorption, but this is a comparatively rare strategy. Instead, atomic emission and mass spectrometry are usually used.
Collisions between the gas-phase sample atoms and the plasma gas pass energy to the sample atoms. This energy can excite the atoms, after which they can lose their energy through atomic emission. By observing the wavelength of the emitted light, the atom's identity can be determined. By observing the intensity of the emission, the concentration of atoms of that type can be determined.
Energy gained through collisions can also ionize the sample atoms. The ions can then be detected by mass spectrometry. In this case, it is the mass of the ions that identify the element and the number of ions that reflect the concentration. This method is referred to as glow discharge mass spectrometry (GDMS) and it has detection limits down to the sub-ppb range for most elements that are nearly matrix-independent. | 0 | Theoretical and Fundamental Chemistry |
Progesterone is used as a medication. It is used in combination with estrogens mainly in hormone therapy for menopausal symptoms and low sex hormone levels in women. It may also be used alone to treat menopausal symptoms. Studies have shown that transdermal progesterone (skin patch) and oral micronized progesterone are effective treatments for certain symptoms of menopause such as hot flashes and night sweats, which are otherwise referred to as vasomotor symptoms or VMS.
It is also used in women to support pregnancy and fertility and to treat gynecological disorders. Progesterone has been shown to prevent miscarriage in women with 1) vaginal bleeding early in their current pregnancy and 2) a previous history of miscarriage. Progesterone can be taken by mouth, through the vagina, and by injection into muscle or fat, among other routes. | 0 | Theoretical and Fundamental Chemistry |
Funded by the European Commission- Horizon 2020 and European Green Deal
Duration: 4 years (October 2021-September 2025)
Objective: SophiA enables African countries to pursue sustainable pathways of development through a low-carbon, climate resilient and green growth trajectory, leapfrogging fossil fuels and high global warming potential refrigerant technologies. | 0 | Theoretical and Fundamental Chemistry |
One of the applications of Knudsen layer is in the coma of comets. It has been used specially in the coma chemistry model (ComChem model). | 1 | Applied and Interdisciplinary Chemistry |
Carbon nanofoam is an allotrope of carbon discovered in 1997. Its structure consists of a cluster-assembly of carbon atoms strung together in a loose three-dimensional web, similar to an aerogel. The material has a density of 2–10 mg/cm (0.0012 lb/ft), which is among the lightest materials to date. | 0 | Theoretical and Fundamental Chemistry |
Crude oil is traded as a future on both the NYMEX and ICE exchanges. Futures contracts are agreements in which buyers and sellers agree to purchase and deliver specific amounts of physical crude oil on a given date in the future. A contract covers any multiple of 1000 barrels and can be purchased up to nine years into the future. | 0 | Theoretical and Fundamental Chemistry |
The Hirao coupling (also called the Hirao reaction or the Hirao cross-coupling) is the chemical reaction involving the palladium-catalyzed cross-coupling of a dialkyl phosphite and an aryl halide to form a phosphonate.
This reaction is named after Toshikazu Hirao and is related to the Michaelis-Arbuzov reaction. In contrast to the classic Michaelis-Arbuzov reaction, which is limited to alkyl phosphonates, the Hirao coupling can also deliver aryl phosphonates. | 0 | Theoretical and Fundamental Chemistry |
Uncontrolled growth is a necessary step for the development of all cancers. In many cancers (e.g. melanoma), a defect in the MAP/ERK pathway leads to that uncontrolled growth. Many compounds can inhibit steps in the MAP/ERK pathway, and therefore are potential drugs for treating cancer, such as Hodgkin disease.
The first drug licensed to act on this pathway is sorafenib — a Raf kinase inhibitor. Other Raf inhibitors include SB590885, PLX4720, XL281, RAF265, encorafenib, dabrafenib, and vemurafenib.
Some MEK inhibitors include cobimetinib, CI-1040, PD0325901, binimetinib (MEK162), selumetinib, and trametinib (GSK1120212)
It has been found that acupoint-moxibustion has a role in relieving alcohol-induced gastric mucosal injury in a mouse model, which may be closely associated with its effects in up-regulating activities of the epidermal growth factor/ERK signal transduction pathway.
RAF-ERK pathway is also involved in the pathophysiology of Noonan syndrome, a polymalformative disease.
Protein microarray analysis can be used to detect subtle changes in protein activity in signaling pathways. The developmental syndromes caused by germline mutations in genes that alter the RAS components of the MAP/ERK signal transduction pathway are called RASopathies. | 1 | Applied and Interdisciplinary Chemistry |
HFCs were developed in the 1990s to substitute for substances such as chlorofluorocarbons (CFCs) and hydrochlorofluorocarbons (HCFCs). As these substances were found to deplete the ozone layer, the Montreal Protocol began to lay down provisions for them to be phased-out globally after the agreement was ratified in 1987.
PFCs and SF were already in use prior to the Montreal Protocol.
NF use has grown since the 1990s along with the rapid expansion of the microelectronics fabrication industry. | 1 | Applied and Interdisciplinary Chemistry |
In organic chemistry, a sulfoxide, also called a sulphoxide, is an organosulfur compound containing a sulfinyl () functional group attached to two carbon atoms. It is a polar functional group. Sulfoxides are oxidized derivatives of sulfides. Examples of important sulfoxides are alliin, a precursor to the compound that gives freshly crushed garlic its aroma, and dimethyl sulfoxide (DMSO), a common solvent. | 0 | Theoretical and Fundamental Chemistry |
The sulfur cycle in marine environments has been well-studied via the tool of sulfur isotope systematics expressed as δS. The modern global oceans have sulfur storage of , mainly occurring as sulfate with the δS value of +21‰. The overall input flux is with the sulfur isotope composition of ~3‰. Riverine sulfate derived from the terrestrial weathering of sulfide minerals (δS = +6‰) is the primary input of sulfur to the oceans. Other sources are metamorphic and volcanic degassing and hydrothermal activity (δS = 0‰), which release reduced sulfur species (such as HS and S). There are two major outputs of sulfur from the oceans. The first sink is the burial of sulfate either as marine evaporites (such as gypsum) or carbonate-associated sulfate (CAS), which accounts for (δS = +21‰). The second sulfur sink is pyrite burial in shelf sediments or deep seafloor sediments (; δS = −20‰). The total marine sulfur output flux is which matches the input fluxes, implying the modern marine sulfur budget is at steady state. The residence time of sulfur in modern global oceans is 13,000,000 years. | 0 | Theoretical and Fundamental Chemistry |
The most commonly used description of flow conditions within the pipe is the flow velocity profile. Fig.(1) shows the typical flow velocity profile for natural gas measurement. The shape of the flow velocity profile is given by the following equation, ---- (1) <br />
The value of n determines the shape of the flow velocity profile. The eq.(1) can be used to determine the flow profile's shape within the pipe by fitting a curve to experimentally measured velocity data. In 1993, the transverse flow velocities were being measured within the high pressure natural gas environment using hot wire technology to accomplish the data fit. A fully developed flow profile was used as the reference state for meter calibration and determination of Coefficient of Discharge (Cd). For Reynolds Number to n is approximately 7.5; for Re of , n is approximately 10.0 where a fully developed profile in a smooth pipe was assumed. Since n is a function of Reynolds Number and friction factor, more accurate values of n can be estimated by using the eq.(2),
---- (2) <br />
Where, f is friction factor. A good estimate of a fully developed velocity profile can be used for those without adequate equipment to actually measure the flow velocities within the pipe. The following straight pipe equivalent length in eq.(3) was utilized to ensure a fully developed flow profile exists.
---- (3) <br />
In eq.(3) the pipe lengths required is significant, hence we need some devices that can able to condition the flow over a shorter pipe length allowing metering packages to be cost competitive and accurate. Here the velocity flow profile is generally three-dimensional. Normally the description requires no axial orientation indication if the profile is asymmetric and if it does exists, then axial orientation with respect to some suitable plane of reference is required. Asymmetry exists downstream of installation effects such as elbows or tees. Usually, the velocity flow profile is described on two planes 90° apart. Using the latest software technology a full pipe cross sectional description of the velocity profile is possible provided sufficient data points are given. | 1 | Applied and Interdisciplinary Chemistry |
Many other organisms obtained chloroplasts from the primary chloroplast lineages through secondary endosymbiosis—engulfing a red or green alga that contained a chloroplast. These chloroplasts are known as secondary plastids.
While primary chloroplasts have a double membrane from their cyanobacterial ancestor, secondary chloroplasts have additional membranes outside of the original two, as a result of the secondary endosymbiotic event, when a nonphotosynthetic eukaryote engulfed a chloroplast-containing alga but failed to digest it—much like the cyanobacterium at the beginning of this story. The engulfed alga was broken down, leaving only its chloroplast, and sometimes its cell membrane and nucleus, forming a chloroplast with three or four membranes—the two cyanobacterial membranes, sometimes the eaten algas cell membrane, and the phagosomal vacuole from the hosts cell membrane.
The genes in the phagocytosed eukaryotes nucleus are often transferred to the secondary hosts nucleus.
Cryptomonads and chlorarachniophytes retain the phagocytosed eukaryote's nucleus, an object called a nucleomorph, located between the second and third membranes of the chloroplast.
All secondary chloroplasts come from green and red algae—no secondary chloroplasts from glaucophytes have been observed, probably because glaucophytes are relatively rare in nature, making them less likely to have been taken up by another eukaryote. | 0 | Theoretical and Fundamental Chemistry |
Technicon sold its business to Revlon in 1980 who later sold the company to separate clinical (Bayer) and industrial (Bran+Luebbe - now SEAL Analytical) buyers in 1987. At the time, industrial applications accounted for about 20% of CFA machines sold.
In 1974 Ruzicka and Hansen carried out in Denmark and in Brasil initial experiments on a competitive technique, that they termed flow injection analysis (FIA). Since then the technique found worldwide use in research and routine applications, and was further modified through miniaturization and by replacing continuous flow with computer controlled programmable flow.
During the 1960s industrial laboratories were hesitant to use the autoanalyzer. Acceptance by regulatory agencies eventually came about by demonstration that the techniques are no different from a recording spectrophotometer with reagents and samples added at the exact chemical ratios as traditionally accepted manual methods.
The best known of Technicon's CFA instruments are the AutoAnalyzer II (introduced 1970), the Sequential Multiple Analyzer (SMA, 1969), and the Sequential Multiple Analyzer with Computer (SMAC, 1974). The Autoanalyzer II (AAII) is the instrument that most EPA methods were written on and reference. The AAII is a second generation segmented flow analyzer that uses 2 millimeter ID glass tubing and pumps reagent at flow rates of 2 - 3 milliliters per minute. Typical sample throughput for the AAII is 30 - 60 samples per hour. Third generation segmented flow analyzers were proposed in the literature, but not developed commercially until Alpkem introduced the RFA 300 in 1984. The RFA 300 pumps at flow rates less than 1 milliliter per minute through 1 millimeter ID glass mixing coils. Throughput on the RFA can approach 360 samples per hour, but averages closer to 90 samples per hour on most environmental tests. In 1986, Technicon (Bran+Luebbe) introduced its own microflow TRAACS-800 system.
Bran+Luebbe continued to manufacture the AutoAnalyzer II and TRAACS, a micro-flow analyzer for environmental and other samples, introduced the AutoAnalyzer 3 in 1997 and the QuAAtro in 2004. The Bran+Luebbe CFA business was bought by SEAL Analytical in 2006 and they continue to manufacture, sell and support the AutoAnalyzer II/3 and QuAAtro CFA systems, as well as Discrete Analyzers.
And there are other manufacturers of CFA instruments.
Skalar Inc., subsidiary of Skalar Analytical, founded in 1965, which has its head office in Breda (NL), is since its founding an independent company, fully owned by its personnel. Development in robotic analyzers, TOC and TN equipment, and monitors has extended the product lines of its long life SAN++ Continuous Flow Analyzers. Software packages for data acquisition and analyzer control are also in house products, running with latest software demands and handles all analyzer hardware combinations.
Astoria-Pacific International, for example, was founded in 1990 by Raymond Pavitt, who previously owned Alpkem. Based in Clackamas, Oregon, U.S.A., Astoria-Pacific manufactures its own micro-flow systems. Its products include the Astoria Analyzer lines for Environmental and Industrial applications; the SPOTCHECK Analyzer for Neonatal screening; and FASPac (Flow Analysis Software Package) for data acquisition and computer interface.
FIAlab Instruments, Inc., in Seattle, Washington, also manufactures several analyzer systems.
Alpkem was purchased by Perstorp Group, and then later by OI Analytical in College Station Texas. OI Analytical manufactures the only segmented flow analyzer that uses polymeric tubing in place of glass mixing coils. OI is also the only major instrument manufacturer that provides segmented flow analysis (SFA) and flow injection analysis (FIA) options on the same platform. | 0 | Theoretical and Fundamental Chemistry |
Rate constants can be derived from the dataset published on the website [http://udfa.net]. Rate constants have the form:
k(T) = alpha*(T/300)*exp(-gamma/T)cms
The following table has the rate constants calculated for a typical temperature in a dense cloud T=10 K.
Formation rates r can be obtained using the rate constants k(T) and the abundances of the reactants species C and D:
r=k(T)[C][D]
where [Y] represents the abundance of the specie Y. In this approach, abundances were taken from The UMIST database for astrochemistry 2006, and the values are relatives to the H density. Following table shows the ratio r/r in order to get a view of the most important reactions.
The results suggest that (1a) reaction is the most prominent reaction in dense clouds. It is in concordance with Harju et al. 2000.
Next table shows the results by doing the same procedure for destruction reaction:
Results shows that, 1A reaction is the main sink for HO in dense clouds. | 1 | Applied and Interdisciplinary Chemistry |
Very long-chain acyl-coenzyme A dehydrogenase deficiency (VLCAD deficiency) is a genetic disorder that affects the bodys ability to break down certain fats. In the β-oxidation cycle, VLCADs role involves the removal of two hydrogen atoms from the acyl-CoA molecule, forming a double bond and converting it into trans-2-enoyl-CoA. This crucial first step in the cycle is essential for the fatty acid to undergo further processing and energy production. When there is a deficiency in VLCAD, the body struggles to effectively break down long-chain fatty acids. This can lead to a buildup of these fats and a shortage of energy, particularly during periods of fasting or increased physical activity.
* Severe Early-Onset Cardiac and Multiorgan Failure Form: symptoms appear within days of birth and include hypertrophic/dilated cardiomyopathy, fluid around heart (pericardial effusion), heart rhythm problems (arrhythmias), hepatomegaly and occasional intermittent hypoglycemia
* Hepatic or Hypoketotic Hypoglycemic Form: typically appears in early childhood with hypoketotic hypoglycemia
* Later-Onset Episodic Myopathic Form: presents with muscle breakdown after exercise (intermittent rhabdomyolysis), muscle cramps and pain, exercise intolerance and low blood sugar
* Low-fat diet
* Use of medium-chain triglyceride (MCT) supplements
* Regular, frequent feeding, especially for infants and children
* Snacks high in complex carbohydrates before bedtime
* Guided and limited exercise for older individuals
* Administration of high-energy fluids intravenously
* Avoiding L-carnitine and IV fats
* Plenty of fluids and urine alkalization for muscle breakdown | 1 | Applied and Interdisciplinary Chemistry |
Index inducer or just inducer predictably induce metabolism via a given pathway and are commonly used in prospective clinical drug-drug interaction studies.
Strong, moderate, and weak inducers are drugs that decreases the AUC of sensitive index substrates of a given metabolic pathway by ≥80%, ≥50% to <80%, and ≥20% to <50%, respectively. | 1 | Applied and Interdisciplinary Chemistry |
Oligosaccharides are a component of fibre from plant tissue. FOS and inulin are present in Jerusalem artichoke, burdock, chicory, leeks, onions, and asparagus. Inulin is a significant part of the daily diet of most of the world’s population. FOS can also be synthesized by enzymes of the fungus Aspergillus niger acting on sucrose. GOS is naturally found in soybeans and can be synthesized from lactose. FOS, GOS, and inulin are also sold as nutritional supplements. | 0 | Theoretical and Fundamental Chemistry |
Transient expression, more frequently referred to "transient gene expression", is the temporary expression of genes that are expressed for a short time after nucleic acid, most frequently plasmid DNA encoding an expression cassette, has been introduced into eukaryotic cells with a chemical delivery agent like calcium phosphate (CaPi) or polyethyleneimine (PEI). However, unlike "stable expression," the foreign DNA does not fuse with the host cell DNA, resulting in the inevitable loss of the vector after several cell replication cycles. The majority of transient gene expressions are done with cultivated animal cells. The technique is also used in plant cells; however, the transfer of nucleic acids into these cells requires different methods than those with animal cells. In both plants and animals, transient expression should result in a time-limited use of transferred nucleic acids, since any long-term expression would be called "stable expression."
Methodology varies depending on the organism to transform. While plants can be transformed with a construct introduced into Agrobacterium tumefaciens via agroinfiltration or floral dip, most animal cells would require a viral vector. In humans, the field of transient transformation advanced rapidly during the 2020–2021 COVID-19 pandemic with major COVID-19 vaccines using either direct mRNA transfer into human or adenovirus vectors, with the RNA being expressed in the host human to produce spike proteins that induce an immune response. | 1 | Applied and Interdisciplinary Chemistry |
Depending on the general substrate on which the assay principle is applied:
#Bioassay: when the response is biological activity of live objects. Examples include
##in vivo, whole organism (e.g. mouse or other subject injected with a drug)
##ex vivo body part (e.g. leg of a frog)
##ex vivo organ (e.g. heart of a dog)
##ex vivo part of an organ (e.g. a segment of an intestine).
##tissue (e.g. limulus lysate)
##cell (e.g. platelets)
#Ligand binding assay when a ligand (usually a small molecule) binds a receptor (usually a large protein).
#Immunoassay when the response is an antigen antibody binding type reaction. | 1 | Applied and Interdisciplinary Chemistry |
These types of forming process involve the application of mechanical force at room temperature. However, some recent developments involve the heating of dies and/or parts. Advancements in automated metalworking technology have made progressive die stamping possible which is a method that can encompass punching, coining, bending and several other ways below that modify metal at less cost while resulting in less scrap.
* Bending
* Coining
* Decambering
* Deep drawing (DD)
* Foldforming
* Hydroforming (HF)
* Hot metal gas forming
* Hot press hardening
* Incremental forming (IF)
* Spinning, Shear forming or Flowforming
* Planishing
* Raising
* Roll forming
* Roll bending
* Repoussé and chasing
* Rubber pad forming
* Shearing
* Stamping
* Superplastic forming (SPF)
* Wheeling using an English wheel (wheeling machine) | 1 | Applied and Interdisciplinary Chemistry |
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