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Historically, blotting paper or cloth were used to extract filter coffee.
Modern coffee filters of paper are made from about 100 g/m crêped paper. The crêping allows the coffee to flow freely between the filter and the filtration funnel. The raw materials (pulp) for the filter paper are coarse long fiber, often from fast growing trees. For example, Melitta uses up to 60% of bambus in their filters since 1998. Both bleached and unbleached qualities are made. Coffee filters are made in different shapes and sizes to fit into different holders.
Most notable are the (paper) coffee filter systems introduced by Melitta (1908, 1932, 1936, 1965), Chemex (1941) and Hario (2004).
Important parameters are strength, compatibility, efficiency and capacity.
Tea bags also work as a kind of paper filter. They are made from abacá fibers, a very thin and long fiber manilla hemp. Often the paper is augmented with a minor portion of synthetic fibers. The bag paper is very porous and thin and has high wet strength. | 0 | Theoretical and Fundamental Chemistry |
Zeise made several scientific discoveries. His discovery of mercaptans (thiols) in 1832 and thioethers in 1833, was once a weighty support for the influential (now obsolete) "Radical Theory" which Berzelius and Liebig developed, provoking important chemical studies. His discovery and work on xanthates, led to the widespread use of xanthate salts in synthetic chemistry.
In 1830, Zeise attempted to react platinum chloride with ethanol, leading to a series of platinum-based organometallic compounds. One of these compounds, originally referred to by Zeise himself as “sal kalicoplatinicus inflammabilis”, was subsequently named after him according to the tradition of the day – it is still called Zeises salt. Zeises claim that the newly discovered salt contained ethylene was received with distrust by Justus von Liebig, whose understandable attacks on Zeise were quite unjustified. The complex indeed contains ethylene. Attempts to establish the correct structure and composition of Zeises salt drove much basic research during the second half of the 19th century and led to a greater sophistication in organometallic chemistry. The structure of Zeises salt was definitively resolved only with the advent of X-ray crystallography and the nature of its platinum to ethylene bond was not understood until the development of the Dewar–Chatt–Duncanson model in the 1950s.
Shortly before he died, Zeise published his attempts to purify the pigment carotene from carrot juice while in the Polytechnic Institute; finding it to be soluble in carbon disulfide and correctly identifying it as a hydrocarbon. | 0 | Theoretical and Fundamental Chemistry |
NDR is the normalized measure of sequencing depth, which was downsampled to 2000 folds as a default in the 2000 base pair windows during read preprocessing and quality control steps. | 1 | Applied and Interdisciplinary Chemistry |
A variety of natural and synthetic inhibitors of ATP synthase have been discovered. These have been used to probe the structure and mechanism of ATP synthase. Some may be of therapeutic use. There are several classes of ATP synthase inhibitors, including peptide inhibitors, polyphenolic phytochemicals, polyketides, organotin compounds, polyenic α-pyrone derivatives, cationic inhibitors, substrate analogs, amino acid modifiers, and other miscellaneous chemicals. Some of the most commonly used ATP synthase inhibitors are oligomycin and DCCD. | 0 | Theoretical and Fundamental Chemistry |
At one time, stable carbenes were thought to reversibly dimerise through the so-called Wanzlick equilibrium. However, imidazol-2-ylidenes and triazol-5-ylidenes are thermodynamically stable and do not dimerise, and have been stored in solution in the absence of water and air for years. This is presumably due to the aromatic nature of these carbenes, which is lost upon dimerisation. In fact imidazol-2-ylidenes are so thermodynamically stable that only in highly constrained conditions are these carbenes forced to dimerise.
Chen and Taton made a doubly tethered diimidazol-2-ylidene by deprotonating the respective diimidazolium salt. Only the deprotonation of the doubly tethered diimidazolium salt with the shorter methylene bridge (–CH–) resulted in the dicarbene dimer:
If this dimer existed as a dicarbene, the electron lone pairs on the carbenic carbon would be forced into close proximity. Presumably the resulting repulsive electrostatic interactions would have a significant destabilising effect. To avoid this electronic interaction, the carbene units dimerise.
On the other hand, heteroamino carbenes (such as RN–C–OR or RN–C–SR) and non-aromatic carbenes such as diaminocarbenes (such as RN–C–NR) have been shown to dimerise, albeit quite slowly. This has been presumed to be due to the high barrier to singlet state dimerisation:
Diaminocarbenes do not truly dimerise, but rather form the dimer by reaction via formamidinium salts, a protonated precursor species. Accordingly, this reaction can be acid catalysed. This reaction occurs because unlike imidazolium based carbenes, there is no loss of aromaticity in protonation of the carbene.
Unlike the dimerisation of triplet state carbenes, these singlet state carbenes do not approach head to head ("least motion"), but rather the carbene lone pair attacks the empty carbon p-orbital ("non-least motion"). Carbene dimerisation can be catalyzed by both acids and metals. | 0 | Theoretical and Fundamental Chemistry |
* Member of the Lithuanian Biochemical Society (since 2003)
* Member of the Royal Society of Chemistry (since 2016)
* Member of the International Chemical Biology Society (since 2017)
* Member of the American Chemical Society (since 2021)
* Member of the Sigma Xi (since 2023) | 1 | Applied and Interdisciplinary Chemistry |
The most abundant chlorin is the photosynthetic pigment chlorophyll. Chlorophylls have a fifth, ketone-containing ring unlike the chlorins. Diverse chlorophylls exists, such as chlorophyll a, chlorophyll b, chlorophyll d, chlorophyll e, chlorophyll f, and chlorophyll g. Chlorophylls usually feature magnesium as a central metal atom, replacing the two NH centers in the parent. | 1 | Applied and Interdisciplinary Chemistry |
# Particle visualization: Cloud chambers allow scientists to observe the paths of charged particles as they pass through the chamber. By creating a supersaturated vapor environment, the particles ionize the vapor molecules, creating a visible trail of tiny droplets or clouds. This visualization helps researchers study the behavior, properties, and interactions of these particles.
# Particle identification: Cloud chambers can be used to identify different types of particles based on their path and characteristics. By analyzing the curvature, density, and other properties of the particle tracks, scientists can distinguish between various particles, such as electrons, muons, alpha particles, and more.
# Studying radioactivity: Cloud chambers are particularly useful in studying radioactive decay and radiation. Radioactive particles emitted from a radioactive source can be observed and their properties analyzed within the cloud chamber. This helps scientists understand the nature of radioactivity, decay processes, and the behavior of radioactive particles.
# Educational tool:
# Research and discovery: Cloud chambers have been instrumental in numerous scientific discoveries throughout history, including the identification of new particles and the study of particle interactions. By providing a means to observe and analyze particle tracks, cloud chambers have contributed significantly to advancing our knowledge of the subatomic world. | 0 | Theoretical and Fundamental Chemistry |
Principle, in chemistry, refers to a historical concept of the constituents of a substance, specifically those that produce a certain quality or effect in the substance, such as a bitter principle, which is any one of the numerous compounds having a bitter taste.
The idea of chemical principles developed out of the classical elements. Paracelsus identified the tria prima as principles in his approach to medicine. In his book The Sceptical Chymist of 1661, Robert Boyle criticized the traditional understanding of the composition of materials and initiated the modern understanding of chemical elements. Nevertheless, the concept of chemical principles continued to be used. Georg Ernst Stahl published Philosophical Principles of Universal Chemistry in 1730 as an early effort to distinguish between mixtures and compounds. He writes, "the simple are Principles, or the first material causes of Mixts;..." To define a Principle, he wrote
:A Principle is defined, à priori, that in a mix’d matter, which first existed; and a posteriori, that into which it is at last resolved. (...) chemical Principles are called Salt, Sulfur and Mercury (...) or Salt, Oil, and Spirit.
Stahl recounts theories of chemical principles according to Helmont and J. J. Becher. He says Helmont took Water to be the "first and only material Principle of all things." According to Becher, Water and Earth are principles, where Earth is distinguished into three kinds. Stahl also ascribes to Earth the "principle of rest and aggregation."
Historians have described how early analysts used Principles to classify substances:
:The classification of substances varies from one author to the next, but it generally relied on tests to which materials could be submitted or procedures that could be applied to them. "Test" must be understood here in a double sense, experimental and moral: gold was considered noble because it resisted fire, humidity, and being buried underground. Camphor, like sulfur, arsenic, mercury, and ammonia, belonged to the "spirits" because it was volatile. Glass belonged among the metals because, like them, it could be melted. And since the seven known metals – gold, silver, iron, copper, tin, lead, and mercury – were characterized by their capacity to be melted, what made a metal a metal was defined by reference to the only metal that was liquid at room temperature, mercury or quicksilver. But "common" mercury differed from the mercuric principle, which was cold and wet. Like all other metals, it involved another "principle", which was hot and dry, sulfur.
Guillaume-François Rouelle "attributed two functions to principles: that of forming mixts and that of being an agent or instrument of chemical principles."
:Thus the four principles, earth, air, fire, and water, were principles both of the chemist's operations and of the mixts they operated upon. As instruments they were, unlike specific chemical reagents, "natural and general," always at work in every chemical operation. As constituent elements, they did not contradict the chemistry of displacement but transcended it: the chemist could never isolate or characterize an element as he characterized a body; an element was not isolable, for it could not be separated from a mixt without re-creating a new mixt in the process. | 1 | Applied and Interdisciplinary Chemistry |
The EQCM sensitivity factor K can be calculated by combing the electrochemical cell measured charge density and QCM measured frequency shift. The sensitivity factor is only valid when the mass change on the electrode is homogenous. Otherwise, K is taken as the average sensitivity factor of the EQCM.
where is the measured frequency shift (Hz), S is the quartz crystal active area (cm), ρ is the density of quartz crystal, is the quartz crystal shear modulus and is the fundamental quartz crystal frequency. K is the intrinsic sensitivity factor of the EQCM.
In a certain electrolyte solution, a metal film will deposited on the working electrode, which is the QCM sensor surface of QCM.
The charge density () is involved in the electro-reduction of metal ions at a constant current , in a period of time ().
The active areal mass density is calculated by
where is the atomic weight of deposited metal, z is the electrovalency, and F is the Faraday constant.
The experimental sensitivity of the EQCM is calculated by combing and . | 0 | Theoretical and Fundamental Chemistry |
Grb2 is widely expressed and is essential for multiple cellular functions. Inhibition of Grb2 function impairs developmental processes in various organisms and blocks transformation and proliferation of various cell types. It is thus not surprising that targeted gene disruption of Grb2 in mice is lethal at an early embryonic stage. Grb2 is best known for its ability to link the epidermal growth factor receptor tyrosine kinase to the activation of Ras and its downstream kinases, ERK1,2. Grb2 is composed of an SH2 domain flanked on each side by an SH3 domain. Grb2 has two closely related proteins with similar domain organizations, Gads and Grap. Gads and Grap are expressed specifically in hematopoietic cells and function in the coordination of tyrosine kinase mediated signal transduction. | 1 | Applied and Interdisciplinary Chemistry |
Mechanistic target of rapamycin has been shown to interact with:
* ABL1,
* AKT1,
* IGF-IR,
* InsR,
* CLIP1,
* EIF3F
* EIF4EBP1,
* FKBP1A,
* GPHN,
* KIAA1303,
* PRKCD,
* RHEB,
* RICTOR,
* RPS6KB1,
* STAT1,
* STAT3,
* Two-pore channels: TPCN1; TPCN2, and
* UBQLN1. | 1 | Applied and Interdisciplinary Chemistry |
Numerical modelling of bubble column reactors is a way of predicting the multiphase flow to improve the reactor design and understand the reactor fluid dynamics. The recent increase in interest in Computational Fluid Dynamics (CFD) spurred substantial research efforts in determining numerical models that can obtain reasonably accurate predictions with limited computational time, thus overcoming the limitations of traditional empirical methods.
When a dispersed flow is considered, two main models have been developed to predict the complex fluid dynamics phenomena: the Eulerian-Lagrangian and the Eulerian-Eulerian Multi-Fluid models. The Eulerian-Lagrangian model couples the Eulerian description of the continuous phase with a Lagrangian scheme for tracking the individual particulates. The dynamic of the surrounding fluid (continuous phase) is solved through the governing equations, while the particulates (dispersed phase) are tracked independently through the surrounding fluid by computing their trajectory. The interactions between the phases and their impact on both the continuous and the discrete phases can be considered, but it requires a greater computational effort. Consequently, it can not be used to simulate bubble columns at the industrial scale.
The Eulerian-Eulerian model considers each phase as interpenetrating continua. All the phases share a single pressure field, whereas continuity and momentum equations are solved for each phase. The coupling between the phases is achieved considering interfacial source terms. | 1 | Applied and Interdisciplinary Chemistry |
To be representative, the layer must meet the following criteria:
• The volume fraction of each type of particle is the same in the representative layer as in the sample as a whole.
• The surface area fraction of each type of particle is the same in the representative layer as in the sample as a whole.
• The void fraction of the representative layer is the same as in the sample.
• The representative layer is nowhere more than one particle thick. Note this means the “thickness” of the representative layer is not uniform. This criterion is imposed so that we can assume that a given photon of light has only one interaction with the layer. It might be transmitted, remitted, or absorbed as a result of this interaction, but it is assumed not to interact with a second particle within the same layer.
In the above discussion, when we talk about a “type” of particle, we must clearly distinguish between particles of different composition. In addition, however, we must distinguish between particles of different sizes. Recall that scattering is envisioned as a surface phenomenon and absorption is envisioned as occurring at the molecular level throughout the particle. Consequently, our expectation is that the contribution of a “type” of particle to absorption will be proportional to the volume fraction of that particle in the sample, and the contribution of a “type” of particle to scattering will be proportional to the surface area fraction of that particle in the sample. This is why our “representative layer” criteria above incorporate both volume fraction and surface area fraction. Since small particles have larger surface area-to-volume ratios than large particles, it is necessary to distinguish between them. | 0 | Theoretical and Fundamental Chemistry |
An intermetallic (also called intermetallic compound, intermetallic alloy, ordered intermetallic alloy, long-range-ordered alloy) is a type of metallic alloy that forms an ordered solid-state compound between two or more metallic elements. Intermetallics are generally hard and brittle, with good high-temperature mechanical properties. They can be classified as stoichiometric or nonstoichiometic intermetallic compounds.
Although the term "intermetallic compounds", as it applies to solid phases, has been in use for many years, Hume-Rothery has argued that it gives misleading intuition, suggesting a fixed stoichiometry and even a clear decomposition into species. | 1 | Applied and Interdisciplinary Chemistry |
Studies have shown that statins bind reversibly to the HGMR enzyme. The affinity of statins for HGMR enzyme is in the nanomolar range, while the natural substrate's affinity is in the micromolar range. Studies have shown that statins use the conformational flexibility of the HMGR enzyme that causes a shallow hydrophobic groove that the statins exploit and is used to accommodate their hydrophobic moieties. The specificity and the tight binding of statins is due to orientation and bonding interactions that form between the statin and the HMGR enzyme. Polar interactions are formed between the HMG-moiety and residues that are located in the cis loop of the enzyme. These polar interactions are between Ser, Asp, Lys and Lys (Figure 4). The terminal carboxylate of the HMG moiety forms a salt bridge with the cationic Lys of the enzyme. In addition to the polar interaction, Lys participates in a hydrogen bonding network with Glu, Asp and the O5 hydroxyl group of the hydroxyglutartic acid component of the statins. Van der Waals interactions are formed between the hydrophobic side chains of the enzyme, which involve the Leu, Val, Leu, Ala and Leu and the statins. Type 2 statins form polar interaction between the fluorine atom on the fluorophenyl group and the guanidinium group of Arg. In addition to these interactions atorvastatin and rosuvastatin also form unique hydrogen bonds between Ser residue and either a carbonyl oxygen atom (atorvastatin) or a sulfone oxygen atom (rosuvastatin). A unique polar interaction between the Arg side chain and the electronegative sulfone group on rosuvastatin makes it the statin that has the greatest number of bonding interactions with HGMR. | 1 | Applied and Interdisciplinary Chemistry |
The hydrogen is catalytically reacted with nitrogen (derived from process air) to form anhydrous liquid ammonia. It is difficult and expensive, as lower temperatures result in slower reaction kinetics (hence a slower reaction rate) and high pressure requires high-strength pressure vessels that resist hydrogen embrittlement. Diatomic nitrogen is bound together by a triple bond, which makes it relatively inert. Yield and efficiency are low, meaning that the ammonia must be extracted and the gases reprocessed for the reaction to proceed at an acceptable pace.
This step is known as the ammonia synthesis loop:
The gases (nitrogen and hydrogen) are passed over four beds of catalyst, with cooling between each pass to maintain a reasonable equilibrium constant. On each pass, only about 15% conversion occurs, but unreacted gases are recycled, and eventually conversion of 97% is achieved.
Due to the nature of the (typically multi-promoted magnetite) catalyst used in the ammonia synthesis reaction, only low levels of oxygen-containing (especially CO, CO and HO) compounds can be tolerated in the hydrogen/nitrogen mixture. Relatively pure nitrogen can be obtained by air separation, but additional oxygen removal may be required.
Because of relatively low single pass conversion rates (typically less than 20%), a large recycle stream is required. This can lead to the accumulation of inerts in the gas.
Nitrogen gas (N) is unreactive because the atoms are held together by triple bonds. The Haber process relies on catalysts that accelerate the scission of these bonds.
Two opposing considerations are relevant: the equilibrium position and the reaction rate. At room temperature, the equilibrium is in favor of ammonia, but the reaction does not proceed at a detectable rate due to its high activation energy. Because the reaction is exothermic, the equilibrium constant decreases with increasing temperature following Le Châtelier's principle. It becomes unity at around .
Above this temperature, the equilibrium quickly becomes unfavorable at atmospheric pressure, according to the Van 't Hoff equation. Lowering the temperature is unhelpful because the catalyst requires a temperature of at least 400 °C to be efficient.
Increased pressure favors the forward reaction because 4 moles of reactant produce 2 moles of product, and the pressure used () alters the equilibrium concentrations to give a substantial ammonia yield. The reason for this is evident in the equilibrium relationship:
where is the fugacity coefficient of species , is the mole fraction of the same species, is the reactor pressure, and is standard pressure, typically .
Economically, reactor pressurization is expensive: pipes, valves, and reaction vessels need to be strong enough, and safety considerations affect operating at 20 MPa. Compressors take considerable energy, as work must be done on the (compressible) gas. Thus, the compromise used gives a single-pass yield of around 15%.
While removing the ammonia from the system increases the reaction yield, this step is not used in practice, since the temperature is too high; instead it is removed from the gases leaving the reaction vessel. The hot gases are cooled under high pressure, allowing the ammonia to condense and be removed as a liquid. Unreacted hydrogen and nitrogen gases are returned to the reaction vessel for another round. While most ammonia is removed (typically down to 2–5 mol.%), some ammonia remains in the recycle stream. In academic literature, a more complete separation of ammonia has been proposed by absorption in metal halides or zeolites. Such a process is called an absorbent-enhanced Haber process or adsorbent-enhanced Haber–Bosch process. | 0 | Theoretical and Fundamental Chemistry |
UV light is electromagnetic radiation with wavelengths shorter than visible light but longer than X-rays. UV is categorised into several wavelength ranges, with short-wavelength UV (UV-C) considered "germicidal UV". Wavelengths between about 200 nm and 300 nm are strongly absorbed by nucleic acids. The absorbed energy can result in defects including pyrimidine dimers. These dimers can prevent replication or can prevent the expression of necessary proteins, resulting in the death or inactivation of the organism. Recently, it has been shown that these dimers are fluorescent.
* Mercury-based lamps operating at low vapor pressure emit UV light at the 253.7 nm line.
* Ultraviolet light-emitting diode (UV-C LED) lamps emit UV light at selectable wavelengths between 255 and 280 nm.
* Pulsed-xenon lamps emit UV light across the entire UV spectrum with a peak emission near 230 nm.
This process is similar to, but stronger than, the effect of longer wavelengths (UV-B) producing sunburn in humans. Microorganisms have less protection against UV and cannot survive prolonged exposure to it.
A UVGI system is designed to expose environments such as water tanks, rooms and forced air systems to germicidal UV. Exposure comes from germicidal lamps that emit germicidal UV at the correct wavelength, thus irradiating the environment. The forced flow of air or water through this environment ensures exposure of that air or water. | 0 | Theoretical and Fundamental Chemistry |
Examples for more high-tech, intensive or mechanized, often relatively expensive sewage treatment systems are listed below. Some of them are energy intensive as well. Many of them provide a very high level of treatment. For example, broadly speaking, the activated sludge process achieves a high effluent quality but is relatively expensive and energy intensive.
* Activated sludge systems
* Aerobic treatment system
* Enhanced biological phosphorus removal
* Expanded granular sludge bed digestion
* Filtration
* Membrane bioreactor
* Moving bed biofilm reactor
* Rotating biological contactor
* Trickling filter
* Ultraviolet disinfection | 1 | Applied and Interdisciplinary Chemistry |
A constructed wetland is an engineered sequence of water bodies designed to treat wastewater or storm water runoff.
Vegetation in a wetland provides a substrate (roots, stems, and leaves) upon which microorganisms can grow as they break down organic materials. This community of microorganisms is known as the periphyton. The periphyton and natural chemical processes are responsible for approximately 90 percent of pollutant removal and waste breakdown. The plants remove about seven to ten percent of pollutants, and act as a carbon source for the microbes when they decay. Different species of aquatic plants have different rates of heavy metal uptake, a consideration for plant selection in a constructed wetland used for water treatment. Constructed wetlands are of two basic types: subsurface flow and surface flow wetlands.
Constructed wetlands are one example of nature-based solutions and of phytoremediation.
Constructed wetland systems are highly controlled environments that intend to mimic the occurrences of soil, flora, and microorganisms in natural wetlands to aid in treating wastewater. They are constructed with flow regimes, micro-biotic composition, and suitable plants in order to produce the most efficient treatment process. | 1 | Applied and Interdisciplinary Chemistry |
* Phase equilibria data (vapor–liquid, liquid–liquid, solid–liquid), data on azeotropy and zeotropy
* Mixing enthalpies
* Gas solubilities
* Activity coefficients at infinite dilution
* Heat capacities and excess heat capacities
* Volumes, densities, and excess volumes (volume effect of mixing)
* Salt solubilities
* Octanol-water partition coefficients
* Critical data
The mixture data banks contain () approx. 308,000 data sets with 2,157,000 data points for 10,750 components building 84,870 different binary, ternary, and higher systems/combinations. | 0 | Theoretical and Fundamental Chemistry |
Glycogen serves as the secondary long-term energy storage in animal and fungal cells, with the primary energy stores being held in adipose tissue. Glycogen is made primarily by the liver, and the muscles but can also be made by glycogenesis within the brain and stomach.
Glycogen is analogous to starch, a glucose polymer in plants, and is sometimes referred to as animal starch, having a similar structure to amylopectin but more extensively branched and compact than starch. Glycogen is a polymer of α(1→4) glycosidic bonds linked with α(1→6)-linked branches. Glycogen is found in the form of granules in the cytosol/cytoplasm in many cell types and plays an important role in the glucose cycle. Glycogen forms an energy reserve that can be quickly mobilized to meet a sudden need for glucose, but one that is less compact and more immediately available as an energy reserve than triglycerides (lipids).
In the liver hepatocytes, glycogen can compose up to 8 percent (100–120 grams in an adult) of the fresh weight soon after a meal. Only the glycogen stored in the liver can be made accessible to other organs. In the muscles, glycogen is found in a low concentration of one to two percent of the muscle mass. The amount of glycogen stored in the body—especially within the muscles, liver, and red blood cells—varies with physical activity, basal metabolic rate, and eating habits such as intermittent fasting. Small amounts of glycogen are found in the kidneys and even smaller amounts in certain glial cells in the brain and white blood cells. The uterus also stores glycogen during pregnancy to nourish the embryo.
Glycogen is composed of a branched chain of glucose residues. It is primarily stored in the liver and muscles.
* It is an energy reserve for animals.
* It is the chief form of carbohydrate stored in animal organisms.
* It is insoluble in water. It turns brown-red when mixed with iodine.
* It also yields glucose on hydrolysis. | 0 | Theoretical and Fundamental Chemistry |
In physics, the first law of thermodynamics is an expression of the conservation of total energy of a system. The increase of the energy of a system is equal to the sum of work done on the system and the heat added to that system:
where
* is the total energy of a system.
* is the work done on it.
* is the heat added to that system.
In fluid mechanics, the first law of thermodynamics takes the following form:
where
* is the Cauchy stress tensor.
* is the flow velocity.
* and is the heat flux vector.
Because it expresses conservation of total energy, this is sometimes referred to as the energy balance equation of continuous media. The first law is used to derive the non-conservation form of the Navier–Stokes equations. | 0 | Theoretical and Fundamental Chemistry |
A hydrogel is a biphasic material, a mixture of porous, permeable solids and at least 10% by weight or volume of interstitial fluid composed completely or mainly by water. In hydrogels the porous permeable solid is a water insoluble three dimensional network of natural or synthetic polymers and a fluid, having absorbed a large amount of water or biological fluids. These properties underpin several applications, especially in the biomedical area. Many hydrogels are synthetic, but some are derived from nature. The term hydrogel was coined in 1894. | 0 | Theoretical and Fundamental Chemistry |
MOBs are composed of two major components: a metal ion or cluster of metal ions and a biological molecule. Examples include CuHARS which contain copper as the metal ion and cystine as the biological molecule. Another example includes the use of silver as the metal ion in combination with cystine. Cystine is the dimer form of the amino acid cysteine. Cobalt has also been used in combination with cystine to form CoMOBs.
When combined with copper to form CuHARS, the cystine may provide a linker function leading to a linear, high-aspect ratio structure that gives CuHARS its name: copper high-aspect ratio structures. In contrast to CuHARS, MOBs formed with silver and cystine, result in silver nanoparticles with spherical, rounded structure. These have been named AgCysNPs. Figure 1 shows comparative electron microscopy of CuHARS and AgCysNPs. | 0 | Theoretical and Fundamental Chemistry |
Compared to hydrogen in its natural composition on Earth, pure deuterium (H) has a higher melting point (18.72 K vs. 13.99 K), a higher boiling point (23.64 vs. 20.27 K), a higher critical temperature (38.3 vs. 32.94 K) and a higher critical pressure (1.6496 vs. 1.2858 MPa).
The physical properties of deuterium compounds can exhibit significant kinetic isotope effects and other physical and chemical property differences from the protium analogs. HO, for example, is more viscous than normal . Chemically, there are differences in bond energy and length for compounds of heavy hydrogen isotopes compared to protium, which are larger than the isotopic differences in any other element. Bonds involving deuterium and tritium are somewhat stronger than the corresponding bonds in protium, and these differences are enough to cause significant changes in biological reactions. Pharmaceutical firms are interested in the fact that deuterium is harder to remove from carbon than protium.
Deuterium can replace protium in water molecules to form heavy water (HO), which is about 10.6% denser than normal water (so that ice made from it sinks in normal water). Heavy water is slightly toxic in eukaryotic animals, with 25% substitution of the body water causing cell division problems and sterility, and 50% substitution causing death by cytotoxic syndrome (bone marrow failure and gastrointestinal lining failure). Prokaryotic organisms, however, can survive and grow in pure heavy water, though they develop slowly. Despite this toxicity, consumption of heavy water under normal circumstances does not pose a health threat to humans. It is estimated that a person might drink of heavy water without serious consequences. Small doses of heavy water (a few grams in humans, containing an amount of deuterium comparable to that normally present in the body) are routinely used as harmless metabolic tracers in humans and animals. | 0 | Theoretical and Fundamental Chemistry |
Aromatic hydrocarbons are cyclic, and are much less abundant than the other two main hydrocarbon compounds. They are represented by the formula CH, where n is a positive integer. | 0 | Theoretical and Fundamental Chemistry |
Mount Polley mine is a Canadian gold and copper mine located in British Columbia near the towns of Williams Lake and Likely. It consists of two open-pit sites with an underground mining component and is owned and operated by the Mount Polley Mining Corporation, a wholly owned subsidiary of Imperial Metals. In 2013, the mine produced an output of of copper, 45,823 ounces of gold, and 123,999 of silver. The mill commenced operations in 1997 and was closed and placed on care and maintenance in 2019. The company owns of property near Quesnel Lake and Polley Lake where it has mining leases and operations on and mineral claims on . Mineral concentrate is delivered by truck to the Port of Vancouver.
As of January 2020, Mount Polley's Proven and Probable Reserves were 53.8 million tonnes of ore grading 0.34% copper, 0.30 grams per tonne gold and 0.9 grams per tonne silver, equating to 400 million pounds of copper, 517,000 troy ounces of gold and 1.55 million troy ounces of silver.
Mount Polley Mining Company reopened the mine in July 2022. Mount Polley Mining Company estimates that the reopening of the mine created 300 local jobs. | 1 | Applied and Interdisciplinary Chemistry |
Large amounts of research have focused recently on the use of enzymes as a catalyst for the transesterification. Researchers have found that very good yields could be obtained from crude and used oils using lipases. The use of lipases makes the reaction less sensitive to high free fatty-acid content, which is a problem with the standard biodiesel process. One problem with the lipase reaction is that methanol cannot be used because it inactivates the lipase catalyst after one batch. However, if methyl acetate is used instead of methanol, the lipase is not in-activated and can be used for several batches, making the lipase system much more cost-effective. | 0 | Theoretical and Fundamental Chemistry |
Sulfinic acids RSOH are about 1000x more acidic than the corresponding carboxylic acid RCOH. Sulfur is pyramidal, consequently sulfinic acids are chiral. | 0 | Theoretical and Fundamental Chemistry |
Adenylylation, more commonly known as AMPylation, is a process in which an adenosine monophosphate (AMP) molecule is covalently attached to the amino acid side chain of a protein. This covalent addition of AMP to a hydroxyl side chain of the protein is a post-translational modification. Adenylylation involves a phosphodiester bond between a hydroxyl group of the molecule undergoing adenylylation, and the phosphate group of the adenosine monophosphate nucleotide (i.e. adenylic acid). Enzymes that are capable of catalyzing this process are called AMPylators.
The known amino acids to be targeted in the protein are tyrosine and threonine, and sometimes serine. When charges on a protein undergo a change, it affects the characteristics of the protein, normally by altering its shape via interactions of the amino acids which make up the protein. AMPylation can have various effects on the protein. These are properties of the protein like, stability, enzymatic activity, co-factor binding, and many other functional capabilities of a protein. Another function of adenylylation is amino acids activation, which is catalyzed by tRNA aminoacyl synthetase. The most commonly identified protein to receive AMPylation are GTPases, and glutamine synthetase. | 1 | Applied and Interdisciplinary Chemistry |
Loss of gene activity leads to a nutritional requirement (auxotrophy) not exhibited by the wildtype (prototrophy).
Amino acids:
*ala = alanine
*arg = arginine
*asn = asparagine
Some pathways produce metabolites that are precursors of more than one pathway. Hence, loss of one of these enzymes will lead to a requirement for more than one amino acid. For example:
*ilv: isoleucine and valine
Nucleotides:
*gua = guanine
*pur = purines
*pyr = pyrimidine
*thy = thymine
Vitamins:
*bio = biotin
*nad = NAD
*pan = pantothenic acid | 1 | Applied and Interdisciplinary Chemistry |
In organic and organometallic chemistry, an organyl group is an organic substituent with one (sometimes more) free valence(-s) at a carbon atom. The term is often used in chemical patent literature to protect claims over a broad scope. | 0 | Theoretical and Fundamental Chemistry |
A photophore is a glandular organ that appears as luminous spots on various marine animals, including fish and cephalopods. The organ can be simple, or as complex as the human eye; equipped with lenses, shutters, color filters and reflectors, however unlike an eye it is optimized to produce light, not absorb it. The bioluminescence can variously be produced from compounds during the digestion of prey, from specialized mitochondrial cells in the organism called photocytes ("light producing" cells), or, similarly, associated with symbiotic bacteria in the organism that are cultured.
The character of photophores is important in the identification of deep sea fishes. Photophores on fish are used for attracting food or for camouflage from predators by counter-illumination.
Photophores are found on some cephalopods including the firefly squid, which can create impressive light displays, as well as numerous other deep sea organisms such as the pocket shark Mollisquama mississippiensis and the strawberry squid. | 1 | Applied and Interdisciplinary Chemistry |
Many standard states are non-physical states, often referred to as "hypothetical states". Nevertheless, their thermodynamic properties are well-defined, usually by an extrapolation from some limiting condition, such as zero pressure or zero concentration, to a specified condition (usually unit concentration or pressure) using an ideal extrapolating function, such as ideal solution or ideal gas behavior, or by empirical measurements. Strictly speaking, temperature is not part of the definition of a standard state. However, most tables of thermodynamic quantities are compiled at specific temperatures, most commonly or, somewhat less commonly, . | 0 | Theoretical and Fundamental Chemistry |
DNA methyltransferases are inhibited by SAH. Two S-adenosyl--homocysteine cofactor products can bind the active site of DNA methyltransferase 3B and prevent the DNA duplex from binding to the active site, which inhibits DNA methylation. | 1 | Applied and Interdisciplinary Chemistry |
Temperature is an important quantity to know for the understanding of the system. Material properties such as density, thermal conductivity, viscosity, and specific heat depend on temperature, and very high or low temperature can bring unexpected changes in the system. In solid, the heat equation can be used to obtain the temperature distribution inside the material with given geometries.
For steady-state and static case, the heat equation can be written as
where Fourier’s law of conduction is applied.
Applying boundary conditions gives a solution for the temperature distribution. | 0 | Theoretical and Fundamental Chemistry |
Neurturin is encoded for by the NRTN gene located on chromosome 19 in humans and has been shown to promote potent effects on survival and function of developing and mature midbrain dopaminergic neurons (DA) in vitro. In vivo the direct administration of neurturin into substantia nigra of mice models also shows mature DA neuron protection. In addition, neurturin has also been shown to support the survival of several other neurons including sympathetic and sensory neurons of the dorsal root ganglia. Knockout mice have shown that neurturin does not appear essential for survival. However, evidence shows retarded growth of enteric, sensory and parasympathetic neurons in mice upon the removal of neurturin receptors. | 1 | Applied and Interdisciplinary Chemistry |
Jacques-Louis Soret (30 June 1827 – 13 May 1890) was a Swiss chemist and spectroscopist. He studied both spectroscopy and electrolysis. | 1 | Applied and Interdisciplinary Chemistry |
In general ketones () take the suffix "-one" (pronounced own, not won) with a suffixed position number: is pentan-2-one. If a higher precedence suffix is in use, the prefix "oxo-" is used: is 3-oxohexanal. | 0 | Theoretical and Fundamental Chemistry |
Near infrared fluorescence (NIR) detection is a method that can reveal what kinds of chemicals are present in a sample based on their physical properties. By hitting a sample with near infrared light, chemical bonds in the sample vibrate and re-release the light energy at a wavelength characteristic for a specific molecule or chemical bond. It is not yet known if the differences between GMOs and conventional plants are large enough to detect with NIR imaging. Although the technique would require advanced machinery and data processing tools, a non-chemical approach could have some advantages such as lower costs and enhanced speed and mobility. | 1 | Applied and Interdisciplinary Chemistry |
Malic acid was first isolated from apple juice by Carl Wilhelm Scheele in 1785. Antoine Lavoisier in 1787 proposed the name acide malique, which is derived from the Latin word for apple, mālum—as is its genus name Malus.
In German it is named Äpfelsäure (or Apfelsäure) after plural or singular of a sour thing from the apple fruit, but the salt(s) are called Malat(e).
Malic acid is the main acid in many fruits, including apricots, blackberries, blueberries, cherries, grapes, mirabelles, peaches, pears, plums, and quince and is present in lower concentrations in other fruits, such as citrus. It contributes to the sourness of unripe apples. Sour apples contain high proportions of the acid. It is present in grapes and in most wines with concentrations sometimes as high as 5 g/L. It confers a tart taste to wine; the amount decreases with increasing fruit ripeness. The taste of malic acid is very clear and pure in rhubarb, a plant for which it is the primary flavor. It is also the compound responsible for the tart flavor of sumac spice. It is also a component of some artificial vinegar flavors, such as "salt and vinegar" flavored potato chips.
The process of malolactic fermentation converts malic acid to much milder lactic acid. Malic acid occurs naturally in all fruits and many vegetables, and is generated in fruit metabolism.
Malic acid, when added to food products, is denoted by E number E296. It is sometimes used with or in place of the less sour citric acid in sour sweets. These sweets are sometimes labeled with a warning stating that excessive consumption can cause irritation of the mouth. It is approved for use as a food additive in the EU, US and Australia and New Zealand (where it is listed by its INS number 296).
Malic acid contains 10 kJ (2.39 kilocalories) of energy per gram. | 1 | Applied and Interdisciplinary Chemistry |
In the 1940s Craig invented the first apparatus to conduct countercurrent partitioning; he called this the countercurrent distribution Craig apparatus. The apparatus consists of a series of glass tubes that are designed and arranged such that the lighter liquid phase is transferred from one tube to the next. The next major milestone was droplet countercurrent chromatography (DCCC). It uses only gravity to move the mobile phase through the stationary phase which is held in long vertical tubes connected in series. The modern era of CCC began with the development of the planetary centrifuge by Ito which was first introduced in 1966 as a closed helical tube which was rotated on a "planetary" axis as is turned on a "sun" axis.
Centrifugal partition chromatography was introduced in Japan in 1982; the first instrument was built at Sanki Eng. Ltd. in Kyoto. The first instrument consisted of twelve cartridges arranged around the rotor of a centrifuge; the inner volume of each cartridge was about 15 mL for 50 channels. In 1999 Kromaton developed the first FCPC with radial cells. During cell development, the Z cell was completed in 2005 and the twin cell in 2009. In 2017 RotaChrom designed its top performing CPC cells through computed fluid dynamic simulation software. After thousands of simulations, this tool revealed the drawbacks of conventional CPC cell designs and highlighted the unparallel load capacity and scalable cell design of RotaChrom. | 0 | Theoretical and Fundamental Chemistry |
galactosyl-N-acetylglucosaminylgalactosylglucosyl-ceramide b-1,6-N-acetylglucosaminyltransferase - galactosylgalactosylglucosylceramidase - GalP (protein) - GATA zinc finger - gel electrophoresis - gel shift - gel shift assay - gene - gene amplification - gene conversion - gene expression - gene mapping - gene pool - gene therapy - gene transfer - genetic code - genetic counseling - genetic map - genetic marker - genetic screening - genetically modified mouse - genome - genomic blot - genomic clone - genomic library - genotype - geranylgeraniol 18-hydroxylase - germ line - germacrene A alcohol dehydrogenase - gluconate 2-dehydrogenase - glutamate permease - glycerol-3-phosphate-transporting ATPase - glycoprotein - glycosylation - Golgi apparatus - GRE - guanine - guanine-transporting ATPase - | 1 | Applied and Interdisciplinary Chemistry |
This is not the first time that sticky foam has been used by a military force. Reportedly, the U.S. Marine Corps and the U.S. Army have used streams of foam as non-lethal tools for crowd control or restraint of hostile combatants. | 0 | Theoretical and Fundamental Chemistry |
In order to infect a cell, the envelope glycoprotein GP120 of the HIV virus interacts with CD4 (acting as the primary receptor) and a co-receptor: either CCR5 or CXCR4. This binding results in membrane fusion and the subsequent intracellular signaling that facilitates viral invasion. In approximately half of all HIV cases, the viruses using the CCR5 co-receptor seem to favor immediate infection and transmission while those using the CXCR4 receptor do not present until later in the immunologically suppressed stage of the disease. The virus will often switch from using CCR5 to CXCR4 during the course of the infection, which serves as an indicator for the progression of the disease. Recent evidence suggests that some forms of HIV also use the large integrin a4b7 receptor to facilitate increased binding efficiency in mucosal tissues. | 1 | Applied and Interdisciplinary Chemistry |
The fabric softener tray in a top-load washing machine operates by utilizing a Pythagorean siphon to distribute fabric softener diluted with water across the clothing in the washing machine. Before starting the washing machine, the user pours fabric softener below the maximum fabric softener line in the loading tray. This line designates the point where if the softener were to be poured above it, then all the fabric softener would resultingly escape the device due to the mechanics of the Pythagorean siphon. As one pours the fabric softener under the line, it does not escape anywhere because it has not begun to escape through the center chamber. Once the washing machine works to distribute the fabric softener into the tub of the machine, it pours water above the fabric softener loading tray so that the liquid goes overtop the maximum fill line. This starts the Pythagorean siphon process, as the mixture begins to pour through the central chamber, thus causing a seal from the surface tension of the liquids across all the chambers. The weight of the fabric softener diluted with water has no access to the outside air because of the seal which then causes all the mixture to be poured directly into the washing machine. | 1 | Applied and Interdisciplinary Chemistry |
For binary solutions, the thermodynamic criterion which defines the spinodal curve is that the second derivative of free energy with respect to density or some composition variable is zero. | 0 | Theoretical and Fundamental Chemistry |
In 1979, 138 inhabitants of Palm Island, Queensland, Australia, were admitted to hospital, suffering various symptoms of gastroenteritis. All of these were children; in addition, 10 adults were affected but not hospitalised. Initial symptoms, including abdominal pain and vomiting, resembled those of hepatitis; later symptoms included kidney failure and bloody diarrhoea. Urine analysis revealed high levels of proteins, ketones and sugar in many patients, along with blood and urobilinogen in lesser numbers. The urine analysis, along with faecal microscopy and poison screening, could not provide a statistical link to the symptoms. All patients recovered within 4 to 26 days, and at the time there was no apparent cause for the outbreak. Initial thoughts on the cause included poor water quality and diet, however none were conclusive, and the illness was coined the “Palm Island Mystery Disease”.
At the time, it was noticed that this outbreak coincided with a severe algal bloom in the local drinking water supply, and soon after the focus turned to the dam in question. An epidemiological study of this “mystery disease” later confirmed that the Solomon Dam was implicated, as those that became ill had used water from the dam. It became apparent that a recent treatment of the algal bloom with copper sulfate caused lysis of the algal cells, releasing a toxin into the water.
A study of the dam revealed that periodic blooms of algae were caused predominantly by three strains of cyanobacteria: two of the genus Anabaena, and Cylindrospermopsis raciborskii, previously unknown in Australian waters. A mouse bioassay of the three demonstrated that although the two Anabaena strains were non-toxic, C. raciborskii was highly toxic. Later isolation of the compound responsible led to the identification of the toxin cylindrospermopsin.
A later report alternatively proposed that the excess copper in the water was the cause of the disease. The excessive dosing was following the use of least-cost contractors to control the algae, who were unqualified in the field. | 0 | Theoretical and Fundamental Chemistry |
Point groups in two dimensions, sometimes called rosette groups.
They come in two infinite families:
# Cyclic groups C of n-fold rotation groups
# Dihedral groups D of n-fold rotation and reflection groups
Applying the crystallographic restriction theorem restricts n to values 1, 2, 3, 4, and 6 for both families, yielding 10 groups.
The subset of pure reflectional point groups, defined by 1 or 2 mirrors, can also be given by their Coxeter group and related polygons. These include 5 crystallographic groups. The symmetry of the reflectional groups can be doubled by an isomorphism, mapping both mirrors onto each other by a bisecting mirror, doubling the symmetry order. | 0 | Theoretical and Fundamental Chemistry |
Chemistry Education Research and Practice is a quarterly peer-reviewed open access academic journal published by the Royal Society of Chemistry covering chemistry education. The editor-in-chief is Gwen Lawrie of the University of Queensland. The Associate Editors are Ajda Kahveci of DePaul University, Scott E. Lewis of the University of South Florida, and Michael K. Seery of the University of Edinburgh. According to the Journal Citation Reports, the journal has a 2020 impact factor of 2.959.
The journal was originally published by the University of Ioannina, but switched to the Royal Society of Chemistry at the end of 2005 when it merged with University Chemistry Education. The society also publishes Education in Chemistry, a news magazine on the same topic. | 1 | Applied and Interdisciplinary Chemistry |
Apoptosis, the process of programmed cell death, involves complex signaling pathways and cascades of molecular events. This process is needed for proper development during embryonic and fetal growth where there is destruction and reconstruction of cellular structures. In adult organisms, apoptosis is needed to maintain differentiated tissue by striking the balance between proliferation and cell death. It is known that intracellular proteases called caspases degrade the cellular contents of the cell by proteolysis upon activation of the death pathway.
Mammalian cells have two main pathways that lead to apoptosis.
1. Extrinsic pathway: Initiated by extrinsic ligands binding to death receptors on the surface of the cell. An example of this is the binding of tumour necrosis factor-alpha (TNF-alpha) to TNF-alpha receptor. An example of a TNF receptor is Fas (CD95), which recruits activator caspases like caspase-8 upon binding TNF at the cell surface. The activation of the initiator caspases then initiates a downstream cascade of events that results in the induction of effector caspases that function in apoptosis.
2. Intrinsic pathway: This pathway is initiated by intracellular or environmental stimuli. It is focused on detecting the improper functioning of the mitochondria in the cell and, as a result, activates signaling pathways to commit suicide. The membrane permeability of the mitochondria increases and particular proteins are released into the cytoplasm that facilitates the activation of initiator caspases. The particular protein released from the mitochondria is cytochrome c. Cytochrome c then binds to Apaf-1 in the cytosol and results in the activation of initiator caspase-9. The activation of the initiator caspases then initiates a downstream cascade of events that results in the induction of effector caspases that function in apoptosis.
One family of proteins called IAPs plays a role in regulating cell death by inhibiting the process. IAPs like survivin, inhibit apoptosis by physically binding to and inhibiting proper caspase function. The function of IAPs is evolutionarily conserved as Drosophila homologues of IAPs have been shown to be essential for cell survival.
IAPs have been implicated in studies to have a regulatory effect on cell division. Yeast cells with knock-outs of certain IAP genes did not show problems associated with cell death, but showed defects in mitosis characterized by improper chromosome segregation or failed cytokinesis.
Deletion of particular IAPs does not seem to have a profound effect on the cell-death pathway as there is a redundancy of function by the many IAPs that exist in a cell. They have been implicated, however, to play a role in maintaining an anti-apoptotic environment intracellularly. Changing the expression of particular IAPs has shown an increase in spontaneous cell death induction or increased sensitivity to death stimuli. | 1 | Applied and Interdisciplinary Chemistry |
Before MMC was considered as a chromatographic approach, secondary interactions were generally believed to be the main cause of peak tailing.
However, it was discovered afterwards that secondary interactions can be applied for improving separation power. In 1986, Regnier’s group synthesized a stationary phase that had characteristics of anion exchange chromatography (AEX) and hydrophobic interaction chromatography (HIC) on protein separation.
In 1998, a new form of MMC, hydrophobic charge induction chromatography (HCIC), was proposed by Burton and Harding.
In the same year, conjoint liquid chromatography (CLC), which combines different types of monolithic convective interaction media (CIM) disks in the same housing, was introduced by Štrancar et al.
In 1999, Yates’ group [11] loaded strong-cation exchange (SCX) and reversed phase liquid chromatography (RPLC) stationary phases sequentially into a capillary column coupled with tandem mass spectrometry (MS/MS) in the analysis of peptides, which became one of the most efficient technique in proteomics afterwards.
In 2009, Geng’s group first achieved online two-dimensional (2D) separation of intact proteins using a single column possessing separation features of weak-cation exchange chromatography (WCX) and HIC (termed as two-dimensional liquid chromatography using a single column, (2D-LC-1C). | 0 | Theoretical and Fundamental Chemistry |
RAL colour standard charts are used by architects, construction industry and road safety.
The pipe identification colours are as shown in the table. | 1 | Applied and Interdisciplinary Chemistry |
The pharmacology of dextrorphan is similar to that of dextromethorphan (DXM). However, dextrorphan is much more potent as an NMDA receptor antagonist as well much less active as a serotonin reuptake inhibitor, but retains DXM's activity as a norepinephrine reuptake inhibitor.
It also has more affinity for the opioid receptors than dextromethorphan, significantly so at high doses. | 0 | Theoretical and Fundamental Chemistry |
Cytochrome C1 (also known as Complex III subunit 4) is a protein encoded by the CYC1 gene. Cytochrome is a heme-containing subunit of the cytochrome b-c1 complex, which accepts electrons from Rieske protein and transfers electrons to cytochrome c in the mitochondrial respiratory chain. It is formed in the cytosol and targeted to the mitochondrial intermembrane space. Cytochrome c1 belongs to the cytochrome c family of proteins. | 1 | Applied and Interdisciplinary Chemistry |
Antibody elution is the process of removing antibodies that are attached to their targets, such as the surface of red blood cells. Techniques include using heat, a freeze-thaw cycle, ultrasound, acids or organic solvents. No single method is best in all situations. | 0 | Theoretical and Fundamental Chemistry |
The ANKK1 gene is closely linked to dopamine receptor D2 (DRD2) on chromosome band 11q23.1. The A1 allele of the Taq1A polymorphism (rs1800497T), is located ≈10kb downstream of the dopamine receptor DRD2 gene. Dopamine (DA) is a neurotransmitter in the brain, which controls feelings of wellbeing. This sensation results from the interaction of dopamine and other neurotransmitters such as serotonin, the opioids, and other brain chemicals. Dopamine increases the motivation for food cravings and appetite mediation.
The Reward Deficiency Syndrome (RDS) involves the pleasures or reward mechanisms that rely on dopamine. The result of this deficiency is based on the genetic makeup; this helps explain how certain simple genetic anomalies can give rise to complex aberrant behaviours as the ones mentioned previously. The A1 allelic prevalence has been reported to be significantly higher in obese individuals than in lean subjects, moreover, individuals with increased body mass index (BMI) (BMI ≥ 30 kg/m) have fewer DRD2 dopamine receptors. Investigators have also suggested that hormonal mechanism may underline a gender difference in the ability to suppress hunger in relation to this SNP, which may contribute to the greater incidence of obesity in women compared to men. However, authors have pointed out that A1 carriers have difficulty in learning from negative feedback in a reinforcement-learning task and are less efficient at learning to avoid actions that have negative consequences. | 1 | Applied and Interdisciplinary Chemistry |
Antigen transfer in the thymus is the transmission of self-antigens between thymic antigen-presenting cells which contributes to the establishment of T cell central tolerance.
Thymus represents an origin of T cell development and its responsibility is to select functional but also safe T cells which will not attack self tissues. Self-harmful T cells, further referred to as autoreactive T cells, originate in the thymus because of the stochastic process called V(D)J recombination which conducts the generation of T cell receptors (TCRs) and enables their limitless variability. Two processes of central tolerance take place in thymic medulla, namely clonal deletion (recessive tolerance) and T Regulatory cells selection (dominant tolerance) which force autoreactive T cells to apoptosis or skew them into suppressor T regulatory cells (TRegs), respectively, in order to protect body against manifestations of autoimmunity.
These processes are mediated especially by unique subset of stromal cells called Medullary thymic epithelial cells (mTECs) via presentation of Tissue restricted antigens (TRAs) that represent self tissues from almost all parts of the body. | 1 | Applied and Interdisciplinary Chemistry |
This technique is most commonly used by mineralogists and petrologists. Most rocks are aggregates of small mineral grains. These grains may preserve chemical information acquired during their formation and subsequent alteration. This information may illuminate geologic processes such as crystallization, lithification, volcanism, metamorphism, orogenic events (mountain building), and plate tectonics. This technique is also used for the study of extraterrestrial rocks (meteorites), and provides chemical data which is vital to understanding the evolution of the planets, asteroids, and comets.
The change in elemental composition from the center (also known as core) to the edge (or rim) of a mineral can yield information about the history of the crystal's formation, including the temperature, pressure, and chemistry of the surrounding medium. Quartz crystals, for example, incorporate a small, but measurable amount of titanium into their structure as a function of temperature, pressure, and the amount of titanium available in their environment. Changes in these parameters are recorded by titanium as the crystal grows. | 0 | Theoretical and Fundamental Chemistry |
Counter-immunoelectrophoresis and its modification
In comparison to other conventional methods of diagnosis e.g. for viral infection testing, counter-immunoelectrophoresis is a highly specific, simple, and speedy method that does not require sophisticated, expensive tools, input materials, or long-term capacity building. Considering the high informativeness of counter-immunoelectrophoresis, the results in practice can be dubious at times. As a result, by using a manufactured amphiphilic fluorescein-containing copolymer to increase the antigen and antibody interaction, counter-immunoelectrophoresis procedures can be improved. The use of the fluorescein copolymer-antigen mixture improved the association with plasma levels antibodies of animals immunized against hemorrhage illness and enhanced protein concentration in the precipitated zone, according to the findings. The capability of the amphiphilic fluorescein copolymer to boost antigen-antibody association and see the fluorescent accumulation domain may improve the efficiency of counter-immunoelectrophoresis for infectious disease rapid diagnosis.
Immunomethods
The terminologies, immune-methods and immune-chemical techniques refer to a variety of immunoelectrophoresis processes whose results are identified using antibodies and immunological methodologies. As a result, immunomethods' great sensitivity is a beneficial compared to the great expense of utilizing antibodies. Many different types of agarose electrophoresis are used to see how proteins travel under diverse circumstances. Proteins are recognized after the timer has expired by incubating gels with certain antibodies, which are then stained with Comassie blue.
Radial immunodiffusion
The radial immunodiffusion is an immunoassay technique for determining the concentration of a particular protein in a mixture including other modules. It is made up of an agarose gel, just like the others. Furthermore, in this procedure, the materials are placed into round wells in the gel's core part and disperse through it, generating a deposition ring with a diameter relation to the number of unbound protein that has diffused.
Identification of nanomaterial interaction with C3 protein complement and 2D immunoelectrophoresis
2D immunoelectrophoresis is a potential method that can be used for a range of functions involving protein flow of migrants, such as the deep examination of protein opsonization, in succession of first dimension as an activity of protein molar mass and the second dimension as a role of the isoelectric point. Despite the fact that it contains a large number of proteins, each spot on the 2D gel will symbolize a particular protein with a specific molecular mass and feature.
2D immunoelectrophoresis is also provided as a valuable implement for examining the stimulation of the signal transduction pathway, which is an essential factor in researching nanoparticles before in vivo delivery, because it will impact nanoparticle longevity, destination, and bio-distribution. This method employs two-dimensional horizontally agarose protein electrophoresis to specifically identify the association of nanoparticles with the C3 protein. Proteins can be separated in the first dimension according to their molecular mass (the shorter the protein, the far it drifts), and in the second dimension according to their abundance
Some limitations of immunoelectrophoresis
Though immunoelectrophoresis has a number of benefits, it also has certain drawbacks, such as when compared to other methods of electrophoresis, such as immunofixation, this method is sluggish and less precise. It can be difficult to interpret the results. Several tiny monoclonal proteins may be harder to identify. The accessibility of particular antibodies limits its utility in analytical techniques. Traditional (classical or conventional) immunoelectrophoresis has a number of drawbacks, including the fact that it is time consuming and the protocol might take up to 3 days to finish, has limited specificity and sensitivity, and the results can be difficult to read. As a result, newer immunoelectrophoresis techniques have largely supplanted the conventional immunoelectrophoresis. | 1 | Applied and Interdisciplinary Chemistry |
In pharmacology and pharmaceutics, a prototype drug is an individual drug that represents a drug class – group of medications having similar chemical structures, mechanism of action and mode of action. Prototypes are the most important, and typically the first developed drugs within the class, and are used as a reference to which all other drugs are compared. | 1 | Applied and Interdisciplinary Chemistry |
A backdraft (North American English) or backdraught (British English) is the abrupt burning of superheated gases in a fire caused when oxygen rapidly enters a hot, oxygen-depleted environment; for example, when a window or door to an enclosed space is opened or broken. Backdrafts are typically seen as a blast of smoke and/or flame out of an opening of a building. Backdrafts present a serious threat to firefighters. There is some debate concerning whether backdrafts should be considered a type of flashover. | 0 | Theoretical and Fundamental Chemistry |
One of the earliest examples of a nitrosyl complex to be synthesized is Roussins red salt, which is a sodium salt of the anion [Fe(NO)S]. The structure of the anion can be viewed as consisting of two tetrahedra sharing an edge. Each iron atom is bonded linearly to two NO ligands and shares two bridging sulfidi ligands with the other iron atom. Roussins black salt has a more complex cluster structure. The anion in this species has the formula [Fe(NO)S]. It has C symmetry. It consists of a tetrahedron of iron atoms with sulfide ions on three faces of the tetrahedron. Three iron atoms are bonded to two nitrosyl groups. The iron atom on the threefold symmetry axis has a single nitrosyl group which also lies on that axis. | 0 | Theoretical and Fundamental Chemistry |
In the case of a conventional steam-electric power plant using a drum boiler, the surface condenser removes the latent heat of vaporization from the steam as it changes states from vapor to liquid. The condensate pump then pumps the condensate water through a feedwater heater, which raises the temperature of the water by using extraction steam from various stages of the turbine.
Preheating the feedwater reduces the irreversibilities involved in steam generation and therefore improves the thermodynamic efficiency of the system. This reduces plant operating costs and also helps to avoid thermal shock to the boiler metal when the feedwater is introduced back into the steam cycle. | 1 | Applied and Interdisciplinary Chemistry |
Energy returned on energy invested (EROEI) is the ratio of energy delivered by an energy technology to the energy invested to set up the technology. | 0 | Theoretical and Fundamental Chemistry |
It was from the development of the Normative Scenario, that the Army Corps of Engineers developed CERP, the Comprehensive Everglades Restoration Plan. In the plan they created a time line of projects to be completed, the estimated cost and the ultimate results of improving the ecosystem by having native flora and fauna prosper. They also outline the human benefits of the project. Not only will the solution be sustainable, as future generations will be able to enjoy the Everglades, but the correction of the water flow and through the creation of storage facilities will reduce the occurrence of droughts and water shortages in southern Florida. | 1 | Applied and Interdisciplinary Chemistry |
Lost-foam casting is a type of evaporative-pattern casting process that is similar to investment casting except foam is used for the pattern instead of wax. This process takes advantage of the low boiling point of foam to simplify the investment casting process by removing the need to melt the wax out of the mold. | 1 | Applied and Interdisciplinary Chemistry |
Nucleic acid secondary structure is the basepairing interactions within a single nucleic acid polymer or between two polymers. It can be represented as a list of bases which are paired in a nucleic acid molecule.
The secondary structures of biological DNAs and RNAs tend to be different: biological DNA mostly exists as fully base paired double helices, while biological RNA is single stranded and often forms complex and intricate base-pairing interactions due to its increased ability to form hydrogen bonds stemming from the extra hydroxyl group in the ribose sugar.
In a non-biological context, secondary structure is a vital consideration in the nucleic acid design of nucleic acid structures for DNA nanotechnology and DNA computing, since the pattern of basepairing ultimately determines the overall structure of the molecules. | 0 | Theoretical and Fundamental Chemistry |
In Ancient Greek texts, including the Hippocratic Corpus, Timaeus, and others, the term (anaisthēsíā, "without sensation") is attested; from (an-, "without") and (aisthēsis, "sensation").
In 1679, Steven Blankaart publishes Lexicon medicum graeco-latinum with the Latin term anaisthesia. In 1684, an English translation appears titled A Physical Dictionary, with anaisthesia defined as "defect of sensation, as in paralytic and blasted persons". Subsequently, the term and variant spellings like anæsthesia are used in medical literature signifying "insensibility".
In 1846, in a letter, Oliver Wendell Holmes proposes the term anesthesia to be used for the state induced by an agent and anesthetic for the agent itself. Holmes motivates this with earlier uses of anesthesia in medical literature to mean "insensibility", particularly to "objects of touch". | 1 | Applied and Interdisciplinary Chemistry |
α-Endopsychosin is a putative antagonist of the phencyclidine site of the NMDA receptor which was discovered in extracts of porcine brain and may also be endogenous in humans. The compound appears to be a peptide, but has yet to be purified and fully characterized. | 1 | Applied and Interdisciplinary Chemistry |
The suffix -one is used in organic chemistry to form names of organic compounds containing the -C(=O)- group: see ketone. Sometimes a number between hyphens is inserted before it to state which atom the =O atom is attached to. This suffix was extracted from the word acetone. The final "-e" disappears if it is followed by another suffix that starts with a vowel. | 0 | Theoretical and Fundamental Chemistry |
Zero-point energy (ZPE) is the lowest possible energy that a quantum mechanical system may have. Unlike in classical mechanics, quantum systems constantly fluctuate in their lowest energy state as described by the Heisenberg uncertainty principle. Therefore, even at absolute zero, atoms and molecules retain some vibrational motion. Apart from atoms and molecules, the empty space of the vacuum also has these properties. According to quantum field theory, the universe can be thought of not as isolated particles but continuous fluctuating fields: matter fields, whose quanta are fermions (i.e., leptons and quarks), and force fields, whose quanta are bosons (e.g., photons and gluons). All these fields have zero-point energy. These fluctuating zero-point fields lead to a kind of reintroduction of an aether in physics since some systems can detect the existence of this energy. However, this aether cannot be thought of as a physical medium if it is to be Lorentz invariant such that there is no contradiction with Einstein's theory of special relativity.
The notion of a zero-point energy is also important for cosmology, and physics currently lacks a full theoretical model for understanding zero-point energy in this context; in particular, the discrepancy between theorized and observed vacuum energy in the universe is a source of major contention. Yet according to Einstein's theory of general relativity, any such energy would gravitate, and the experimental evidence from the expansion of the universe, dark energy and the Casimir effect shows any such energy to be exceptionally weak. One proposal that attempts to address this issue is to say that the fermion field has a negative zero-point energy, while the boson field has positive zero-point energy and thus these energies somehow cancel each other out. This idea would be true if supersymmetry were an exact symmetry of nature; however, the LHC at CERN has so far found no evidence to support it. Moreover, it is known that if supersymmetry is valid at all, it is at most a broken symmetry, only true at very high energies, and no one has been able to show a theory where zero-point cancellations occur in the low-energy universe we observe today. This discrepancy is known as the cosmological constant problem and it is one of the greatest unsolved mysteries in physics. Many physicists believe that "the vacuum holds the key to a full understanding of nature". | 0 | Theoretical and Fundamental Chemistry |
The vast majority of carbon dioxide emissions by humans come from the burning of fossil fuels. Additional contributions come from cement manufacturing, fertilizer production, and changes in land use like deforestation. Methane emissions originate from agriculture, fossil fuel production, waste, and other sources.
If current emission rates continue then temperature rises will surpass sometime between 2040 and 2070, which is the level the United Nations' Intergovernmental Panel on Climate Change (IPCC) says is "dangerous".
Most greenhouse gases have both natural and human-caused sources. An exception are purely human-produced synthetic halocarbons which have no natural sources. During the pre-industrial Holocene, concentrations of existing gases were roughly constant, because the large natural sources and sinks roughly balanced. In the industrial era, human activities have added greenhouse gases to the atmosphere, mainly through the burning of fossil fuels and clearing of forests. | 1 | Applied and Interdisciplinary Chemistry |
Autapses can be either glutamate-releasing (excitatory) or GABA-releasing (inhibitory), just like their traditional synapse counterparts. Similarly, autapses can be electrical or chemical by nature.
Broadly speaking, negative feedback in autapses tends to inhibit excitable neurons whereas positive feedback can stimulate quiescent neurons.
Although the stimulation of inhibitory autapses did not induce hyperpolarizing inhibitory post-synaptic potentials in interneurons of layer V of neocortical slices, they have been shown to impact excitability. Upon using a GABA-antagonist to block autapses, the likelihood of an immediate subsequent second depolarization step increased following a first depolarization step. This suggests that autapses act by suppressing the second of two closely timed depolarization steps and therefore, they may provide feedback inhibition onto these cells. This mechanism may also potentially explain shunting inhibition.
In cell culture, autapses have been shown to contribute to the prolonged activation of B31/B32 neurons, which significantly contribute food-response behavior in Aplysia. This suggests that autapses may play a role in mediating positive feedback. The B31/B32 autapse was unable to play a role in initiating the neurons activity, although it is believed to have helped sustain the neurons depolarized state. The extent to which autapses maintain depolarization remains unclear, particularly since other components of the neural circuit (i.e. B63 neurons) are also capable of providing strong synaptic input throughout the depolarization. Additionally, it has been suggested that autapses provide B31/B32 neurons with the ability to quickly repolarize. Bekkers (2009) has proposed that specifically blocking the contribution of autapses and then assessing the differences with or without blocked autapses could better illuminate the function of autapses.
Hindmarsh–Rose (HR) model neurons have demonstrated chaotic, regular spiking, quiescent, and periodic patterns of burst firing without autapses. Upon the introduction of an electrical autapse, the periodic state switches to the chaotic state and displays an alternating behavior that increases in frequency with a greater autaptic intensity and time delay. On the other hand, excitatory chemical autapses enhanced the overall chaotic state. The chaotic state was reduced and suppressed in the neurons with inhibitory chemical autapses. In HR model neurons without autapses, the pattern of firing altered from quiescent to periodic and then to chaotic as DC current was increased. Generally, HR model neurons with autapses have the ability to swap into any firing pattern, regardless of the prior firing pattern. | 1 | Applied and Interdisciplinary Chemistry |
Sodium bisulfite solutions can be prepared by treating a solution of suitable base, such as sodium hydroxide or sodium bicarbonate with sulfur dioxide.
:SO + NaOH → NaHSO
:SO + NaHCO → NaHSO + CO
Attempts to crystallize the product yield sodium metabisulfite (also called sodium disulfite), NaSO.
Upon dissolution of the metabisulfite in water, bisulfite is regenerated:
:NaSO + HO → 2 Na + 2 HSO
Sodium bisulfite is formed during the Wellman-Lord process. | 0 | Theoretical and Fundamental Chemistry |
Photosymbiosis is a type of symbiosis where one of the organisms is capable of photosynthesis.
Examples of photosymbiotic relationships include those in lichens, plankton, ciliates, and many marine organisms including corals, fire corals, giant clams, and jellyfish.
Photosymbiosis is important in the development, maintenance, and evolution of terrestrial and aquatic ecosystems, for example in biological soil crusts, soil formation, supporting highly diverse microbial populations in soil and water, and coral reef growth and maintenance.
When one organism lives within another symbiotically it’s called endosymbiosis. Photosymbiotic relationships where microalgae and/or cyanobacteria live within a heterotrophic host organism, are believed to have led to eukaryotes acquiring photosynthesis and to the evolution of plants. | 0 | Theoretical and Fundamental Chemistry |
The difference between enzymatically active and inactive homologues has been noted (and in some cases, understood when comparing catalytically active and inactive proteins residing in recognisable families) for some time at the sequence level, and some pseudoenzymes have also been referred to as prozymes when they were analysed in protozoan parasites. The best studied pseudoenzymes reside amongst various key signalling superfamilies of enzymes, such as the proteases, the protein kinases, protein phosphatases and ubiquitin modifying enzymes. The role of pseudoenzymes as "pseudo scaffolds" has also been recognised and pseudoenzymes are now beginning to be more thoroughly studied in terms of their biology and function, in large part because they are also interesting potential targets (or anti-targets) for drug design in the context of intracellular cellular signalling complexes. | 1 | Applied and Interdisciplinary Chemistry |
CTCF physically binds to itself to form homodimers,
which causes the bound DNA to form loops. CTCF also occurs frequently at the boundaries of sections of DNA bound to the nuclear lamina. Using chromatin immuno-precipitation (ChIP) followed by ChIP-seq, it was found that CTCF localizes with cohesin genome-wide and affects gene regulatory mechanisms and the higher-order chromatin structure. It is currently believed that the DNA loops are formed by the "loop extrusion" mechanism, whereby the cohesin ring is actively being translocated along the DNA until it meets CTCF. CTCF has to be in a proper orientation to stop cohesin. | 1 | Applied and Interdisciplinary Chemistry |
As with Cu, the field of Zn isotope biogeochemistry is still in a relatively early stage, so the Zn isotope compositions of materials in the environment are not well-documented. However, based on a compilation of some reported measurements, it appears that Zn isotope ratios do not vary widely among environmental materials (e.g., plants, minerals, seawater, etc.), as δZn values of materials typically fall within a range of -1 to +1‰. | 0 | Theoretical and Fundamental Chemistry |
Forensic DNA analysis was first used in 1984. It was developed by Sir Alec Jeffreys, who realized that variation in the genetic sequence could be used to identify individuals and to tell individuals apart from one another. The first application of DNA profiles was used by Jeffreys in a double murder mystery in the small English town of Narborough, Leicestershire, in 1985. A 15-year-old school girl by the name of Lynda Mann was raped and murdered in Carlton Hayes psychiatric hospital. The police did not find a suspect but were able to obtain a semen sample.
In 1986, Dawn Ashworth, 15 years old, was also raped and strangled in the nearby village of Enderby. Forensic evidence showed that both killers had the same blood type. Richard Buckland became the suspect because he worked at Carlton Hayes psychiatric hospital, had been spotted near Dawn Ashworths murder scene and knew unreleased details about the body. He later confessed to Dawns murder but not Lynda's. Jefferys was brought into the case to analyze the semen samples. He concluded that there was no match between the samples and Buckland, who became the first person to be exonerated using DNA. Jefferys confirmed that the DNA profiles were identical for the two murder semen samples. To find the perpetrator, DNA samples from the entire male population, more than 4,000 aged from 17 to 34, of the town were collected. They all were compared to semen samples from the crime. A friend of Colin Pitchfork was heard saying that he had given his sample to the police claiming to be Colin. Colin Pitchfork was arrested in 1987 and it was found that his DNA profile matched the semen samples from the murder.
Because of this case, DNA databases were developed. There is the national (FBI) and international databases as well as the European countries (ENFSI: European Network of Forensic Science Institutes). These searchable databases are used to match crime scene DNA profiles to those already in a database. | 0 | Theoretical and Fundamental Chemistry |
This argument for formation of mesocrystals requires only a confined space that the reaction takes place in. As the nanoparticle grow into crystals, they have no choice but to align with each other in such a confined space. | 0 | Theoretical and Fundamental Chemistry |
The book consists of a preface and twelve chapters, labelled books I to XII, without titles. It also has numerous woodcuts that provide annotated diagrams illustrating equipment and processes described in the text. | 1 | Applied and Interdisciplinary Chemistry |
Though the terms equivalence point and endpoint are often used interchangeably, they are different terms. Equivalence point is the theoretical completion of the reaction: the volume of added titrant at which the number of moles of titrant is equal to the number of moles of analyte, or some multiple thereof (as in polyprotic acids). Endpoint is what is actually measured, a physical change in the solution as determined by an indicator or an instrument mentioned above.
There is a slight difference between the endpoint and the equivalence point of the titration. This error is referred to as an indicator error, and it is indeterminate. | 0 | Theoretical and Fundamental Chemistry |
The Langmuir adsorption model deviates significantly in many cases, primarily because it fails to account for the surface roughness of the adsorbent. Rough inhomogeneous surfaces have multiple site types available for adsorption, with some parameters varying from site to site, such as the heat of adsorption. Moreover, specific surface area is a scale-dependent quantity, and no single true value exists for this parameter. Thus, the use of alternative probe molecules can often result in different obtained numerical values for surface area, rendering comparison problematic.
The model also ignores adsorbate–adsorbate interactions. Experimentally, there is clear evidence for adsorbate–adsorbate interactions in heat of adsorption data. There are two kinds of adsorbate–adsorbate interactions: direct interaction and indirect interaction. Direct interactions are between adjacent adsorbed molecules, which could make adsorbing near another adsorbate molecule more or less favorable and greatly affects high-coverage behavior. In indirect interactions, the adsorbate changes the surface around the adsorbed site, which in turn affects the adsorption of other adsorbate molecules nearby. | 0 | Theoretical and Fundamental Chemistry |
Green rust compounds can be synthesized at ordinary ambient temperature and pressure, from solutions containing iron(II) cations, hydroxide anions, and the appropriate intercalatory anions, such as chloride, sulfate, or carbonate.
The result is a suspension of ferrous hydroxide () in a solution of the third anion. This suspension is oxidized by stirring in air, or bubbling air through it. Since the product is very prone to oxidation, it is necessary to monitor the process and exclude oxygen once the desired ratio of and is achieved.
One method first combines an iron(II) salt with sodium hydroxide to form the ferrous hydroxide suspension. Then the sodium salt of the third anion is added, and the suspension is oxidized by stirring in air.
For example, carbonate green rust can be prepared by mixing solutions of iron(II) sulfate and sodium hydroxide; then adding sufficient amount of sodium carbonate solution, followed by the air oxidation step.
Sulfate green rust can be obtained by mixing solutions of ·4 and to precipitate () then immediately adding sodium sulfate and proceeding to the air oxidation step.
A more direct method combines a solution of iron(II) sulfate with , and proceeding to the oxidizing step. The suspension must have a slight excess of (in the ratio of 0.5833 for each ) for the green rust to form; however, too much of it will produce instead an insoluble basic iron sulfate, iron(II) sulfate hydroxide ()·n. The production of green rust is reduced as temperature increases. | 1 | Applied and Interdisciplinary Chemistry |
The widespread use of refrigeration allowed for a vast amount of new agricultural opportunities to open up in the United States. New markets emerged throughout the United States in areas that were previously uninhabited and far-removed from heavily populated areas. New agricultural opportunity presented itself in areas that were considered rural, such as states in the south and in the west. Shipments on a large scale from the south and California were both made around the same time, although natural ice was used from the Sierras in California rather than manufactured ice in the south. Refrigeration allowed for many areas to specialize in the growing of specific fruits. California specialized in several fruits, grapes, peaches, pears, plums, and apples, while Georgia became famous for specifically its peaches. In California, the acceptance of the refrigerated rail cars led to an increase of car loads from 4,500 carloads in 1895 to between 8,000 and 10,000 carloads in 1905. The Gulf States, Arkansas, Missouri and Tennessee entered into strawberry production on a large-scale while Mississippi became the center of the tomato industry. New Mexico, Colorado, Arizona, and Nevada grew cantaloupes. Without refrigeration, this would have not been possible. By 1917, well-established fruit and vegetable areas that were close to eastern markets felt the pressure of competition from these distant specialized centers. Refrigeration was not limited to meat, fruit and vegetables but it also encompassed dairy product and dairy farms. In the early twentieth century, large cities got their dairy supply from farms as far as . Dairy products were not as easily transported over great distances like fruits and vegetables due to greater perishability. Refrigeration made production possible in the west far from eastern markets, so much in fact that dairy farmers could pay transportation cost and still undersell their eastern competitors. Refrigeration and the refrigerated rail gave opportunity to areas with rich soil far from natural channel of transport such as a river, valley trail or harbors. | 0 | Theoretical and Fundamental Chemistry |
Using Bernoulli's equation, the pressure coefficient can be further simplified for potential flows (inviscid, and steady):
where:
: is the flow speed at the point at which pressure coefficient is being evaluated
: is the Mach number, which is taken in the limit of zero
: is the flow's stagnation pressure
This relationship is valid for the flow of incompressible fluids where variations in speed and pressure are sufficiently small that variations in fluid density can be neglected. This assumption is commonly made in engineering practice when the Mach number is less than about 0.3.
* of zero indicates the pressure is the same as the freestream pressure.
* of one corresponds to the stagnation pressure and indicates a stagnation point.
* the most negative values of in a liquid flow can be summed to the cavitation number to give the cavitation margin. If this margin is positive, the flow is locally fully liquid, while if it is zero or negative the flow is cavitating or gas.
Locations where are significant in the design of gliders because this indicates a suitable location for a "Total energy" port for supply of signal pressure to the Variometer, a special Vertical Speed Indicator which reacts to vertical movements of the atmosphere but does not react to vertical maneuvering of the glider.
In an incompressible fluid flow field around a body, there will be points having positive pressure coefficients up to one, and negative pressure coefficients including coefficients less than minus one. | 1 | Applied and Interdisciplinary Chemistry |
*ABCB10 NM_012089
*ABCB7 NM_004299
*ABCD3 NM_002857
*ABCE1 NM_002939
*ABCF1 NM_001090
*ABCF2 NM_005692
*ABCF3 NM_018358
*CALM1 Calmodulin grasps calcium ions
*MFSD11 NM_024311 similar to MSFD10 aka TETRAN or tetracycline transporter-like protein
*MFSD12 NM_174983
*MFSD3 NM_138431
*MFSD5 NM_032889
*SLC15A4 NM_145648
*SLC20A1 NM_005415
*SLC25A11 mitochondrial oxoglutarate/malate carrier
*SLC25A26 NM_173471
*SLC25A28 NM_031212
*SLC25A3 NM_002635
*SLC25A32 NM_030780
*SLC25A38 NM_017875
*SLC25A39 NM_016016
*SLC25A44 NM_014655
*SLC25A46 NM_138773
*SLC25A5 NM_001152
*SLC27A4 NM_005094
*SLC30A1 NM_021194
*SLC30A5 NM_022902
*SLC30A9 NM_006345
*SLC35A2 NM_005660
*SLC35A4 NM_080670
*SLC35B1 NM_005827
*SLC35B2 NM_178148
*SLC35C2 NM_015945
*SLC35E1 NM_024881
*SLC35E3 NM_018656
*SLC35F5 NM_025181
*SLC38A2 NM_018976
*SLC39A1 NM_014437
*SLC39A3 NM_144564
*SLC39A7 NM_006979
*SLC41A3 NM_017836
*SLC46A3 NM_181785
*SLC48A1 NM_017842 | 1 | Applied and Interdisciplinary Chemistry |
For simplicity, assume combustion takes place in a single global irreversible reaction
where is the ith chemical species of the total species and and are the stoichiometric coefficients of the reactants and products, respectively. Then, it can be shown from the law of mass action that the rate of moles produced per unit volume of any species is constant and given by
where is the mass of species i produced or consumed per unit volume and is the molecular weight of species i.
The main approximation involved in Shvab–Zeldovich formulation is that all binary diffusion coefficients of all pairs of species are the same and equal to the thermal diffusivity. In other words, Lewis number of all species are constant and equal to one. This puts a limitation on the range of applicability of the formulation since in reality, except for methane, ethylene, oxygen and some other reactants, Lewis numbers vary significantly from unity. The steady, low Mach number conservation equations for the species and energy in terms of the rescaled independent variables
where is the mass fraction of species i, is the specific heat at constant pressure of the mixture, is the temperature and is the formation enthalpy of species i, reduce to
where is the gas density and is the flow velocity. The above set of nonlinear equations, expressed in a common form, can be replaced with linear equations and one nonlinear equation. Suppose the nonlinear equation corresponds to so that
then by defining the linear combinations and with , the remaining governing equations required become
The linear combinations automatically removes the nonlinear reaction term in the above equations. | 1 | Applied and Interdisciplinary Chemistry |
Chirality is a symmetry property, not a property of any part of the periodic table. Thus many inorganic materials, molecules, and ions are chiral. Quartz is an example from the mineral kingdom. Such noncentric materials are of interest for applications in nonlinear optics.
In the areas of coordination chemistry and organometallic chemistry, chirality is pervasive and of practical importance. A famous example is tris(bipyridine)ruthenium(II) complex in which the three bipyridine ligands adopt a chiral propeller-like arrangement. The two enantiomers of complexes such as [Ru(2,2′-bipyridine)] may be designated as Λ (capital lambda, the Greek version of "L") for a left-handed twist of the propeller described by the ligands, and Δ (capital delta, Greek "D") for a right-handed twist (pictured). Also cf. dextro- and levo- (laevo-).
Chiral ligands confer chirality to a metal complex, as illustrated by metal-amino acid complexes. If the metal exhibits catalytic properties, its combination with a chiral ligand is the basis of asymmetric catalysis. | 0 | Theoretical and Fundamental Chemistry |
Kilju can be refined into moonshine by means of distillation to vodka or rectified spirit, but it is illegal in most countries. It is distinct from rum because it is typically made by molasses, a byproduct of the sugar refining process, or fresh sugar cane juice that has a discernible taste of its own.
Moonshine by country, often distilled from fermented water:
* Cuba: Gualfarina
* Finland: Pontikka
* Latvia: Kandža
* Nicaragua: Cususa
* Poland: Bimber
* Russia: Samogon
* Saudi Arabia: Aragh
* Sweden: Hembränt (HB) | 1 | Applied and Interdisciplinary Chemistry |
Because industrial hydraulic systems operate at hundreds to thousands of PSI and temperatures reaching hundreds of degrees Celsius, severe injuries and death can result from component failures and care must always be taken when performing maintenance on hydraulic systems.
Fire resistance is a property available with specialized fluids. Water-glycol and polyol-ester are some of these specialized fluids that contain excellent thermal and hydrolitic properties, which aid in fire resistance. | 1 | Applied and Interdisciplinary Chemistry |
The constant factor 3 in the definition of the Z-factor is motivated by the normal distribution, for which more than 99% of values occur within three times standard deviations of the mean. If the data follow a strongly non-normal distribution, the reference points (e.g. the meaning of a negative value) may be misleading.
Another issue is that the usual estimates of the mean and standard deviation are not robust; accordingly many users in the high-throughput screening community prefer the "Robust Z-prime" which substitutes the median for the mean and the median absolute deviation for the standard deviation. Extreme values (outliers) in either the positive or negative controls can adversely affect the Z-factor, potentially leading to an apparently unfavorable Z-factor even when the assay would perform well in actual screening
In addition, the application of the single Z-factor-based criterion to two or more positive controls with different strengths in the same assay will lead to misleading results
. The absolute sign in the Z-factor makes it inconvenient to derive the statistical inference of Z-factor mathematically. A recently proposed statistical parameter, strictly standardized mean difference (SSMD), can address these issues. One estimate of SSMD is robust to outliers. | 1 | Applied and Interdisciplinary Chemistry |
In organic chemistry, nitroamines are organic compounds with the general chemical structure . They consist of a nitro group () bonded to an amine. The parent inorganic compound, where both R substituents are hydrogen, is nitramide, . | 0 | Theoretical and Fundamental Chemistry |
First held in 1908, the [https://iifiir.org/en/iir-conferences-series International Congress of Refrigeration] of the IIR is a flagship event that converges industry and research.
Covering all fields of refrigeration, the Congress, which takes place every four years, reunites key international stakeholders and provides perspectives on the future of the industry in line with sustainable development. | 0 | Theoretical and Fundamental Chemistry |
Certain PFASs are no longer manufactured in the United States as a result of phase-outs including the PFOA Stewardship Program (2010-2015), in which eight major chemical manufacturers agreed to eliminate the use of PFOA and PFOA-related chemicals in their products and emissions from their facilities. Although PFOA and PFOS are no longer manufactured in the United States, they are still produced internationally and are imported into the U.S. in consumer goods such as carpet, leather and apparel, textiles, paper and packaging, coatings, rubber, and plastics.
In 2020, manufacturers and the Food and Drug Administration announced an agreement to phase out some types of PFAS that are used in food packaging by 2024.
PFASs are also used by major companies of the cosmetics industry in a wide range of cosmetics, including lipstick, eye liner, mascara, foundation, concealer, lip balm, blush, and nail polish. A 2021 study tested 231 makeup and personal care products and found organic fluorine, an indicator of PFASs, in more than half of the samples. High levels of fluorine were most commonly identified in waterproof mascara (82% of brands tested), foundations (63%), and liquid lipstick (62%). As many as 13 types of individual PFAS compounds were found in each product. Since PFAS compounds are highly mobile, they are readily absorbed through human skin and through tear ducts, and such products on lips are often unwittingly ingested. Manufacturers often fail to label their products as containing PFASs, which makes it difficult for cosmetics consumers to avoid products containing PFASs. In response, Senators Susan Collins of Maine and Richard Blumenthal of Connecticut proposed the No PFAS in Cosmetics Act in the United States Senate. It was also introduced in the United States House of Representatives by Michigan Representative Debbie Dingell, but the U.S. chemical industry lobby has killed efforts to regulate this.
In 2021, Maine became the first U.S. state to ban these compounds in all products by 2030, except for instances deemed "currently unavoidable". | 0 | Theoretical and Fundamental Chemistry |
A variety of mechanical adaptations, such as tip geometry and surface roughness, to aid in neural implant design have been investigated and implemented in recent years. The geometry of an electrode affects the shape of the electric field emitted. The electric field shape, in turn, affects the current density produced by the electrode. Determining optimum surface roughness for neural implants proves to be a challenging topic. Smooth surfaces may be preferable to rougher ones as they may decrease the likelihood of bacterial adsorption and infection. Smooth surfaces would also make it more difficult for the initiation of a corrosion cell. However, creating a rougher, porous surface, may prove beneficial for at least two reasons: decreased potential polarization at the electrode surface as a result of increased surface area and decreased current density, and a decrease in fibrous tissue encapsulation thickness due to opportunity for tissue ingrowth. It has been determined that if interconnected pores with sizes between 25 and 150 micrometers, ingrowth of tissue can occur and can decrease the exterior tissue encapsulation thickness by a factor of approximately 10 (compared to a smooth electrode such as polished platinum-iridium). | 0 | Theoretical and Fundamental Chemistry |
Ferrous metallurgy is the metallurgy of iron and its alloys. The earliest surviving prehistoric iron artifacts, from the 4th millennium BC in Egypt, were made from meteoritic iron-nickel. It is not known when or where the smelting of iron from ores began, but by the end of the 2nd millennium BC iron was being produced from iron ores in the region from Greece to India, and sub-Saharan Africa. The use of wrought iron (worked iron) was known by the 1st millennium BC, and its spread defined the Iron Age. During the medieval period, smiths in Europe found a way of producing wrought iron from cast iron, in this context known as pig iron, using finery forges. All these processes required charcoal as fuel.
By the 4th century BC southern India had started exporting wootz steel, with a carbon content between pig iron and wrought iron, to ancient China, Africa, the Middle East, and Europe. Archaeological evidence of cast iron appears in 5th-century BC China. New methods of producing it by carburizing bars of iron in the cementation process were devised in the 17th century. During the Industrial Revolution, new methods of producing bar iron by substituting coke for charcoal emerged, and these were later applied to produce steel, ushering in a new era of greatly increased use of iron and steel that some contemporaries described as a new "Iron Age".
In the late 1850s Henry Bessemer invented a new steelmaking process which involved blowing air through molten pig-iron to burn off carbon, and so producing mild steel. This and other 19th-century and later steel-making processes have displaced wrought iron. Today, wrought iron is no longer produced on a commercial scale, having been displaced by the functionally equivalent mild or low-carbon steel. | 1 | Applied and Interdisciplinary Chemistry |
A transcription unit is a set of one or more genes transcribed from a single promoter. A TU may also include regulatory protein binding sites affecting this promoter and a terminator. A complex operon with several promoters contains, therefore, several transcription units. A transcription unit must include all the genes in an operon. | 1 | Applied and Interdisciplinary Chemistry |
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