CF allows the single/low copy sequences and the repetitive sequences of a genome to be studied independently of each other. It can also be used to fractionate highly repetitive DNA from moderately repetitive sequences or to further fractionate isolated kinetic components. CF is most accurately performed if fractionation is based upon the results of a Cot analysis.
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Improvements of the understanding regarding the way in which iron isotopes fractionate in the geosphere can help to better understand geologic processes of formation.
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Variations in iron isotopes are caused by a number of chemical processes which result in the preferential incorporation of certain isotopes of iron into certain phases. Many of the chemical processes which fractionate iron are not well understood and are still being studied. The most well-documented chemical processes which fractionate iron isotopes relate to its redox chemistry, the evaporation and condensation of iron, and the diffusion of dissolved iron through systems. These processes are described in more detail below.
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Separated from a gas stream, NGLs are an undifferentiated batch of light hydrocarbons — ethane, propane, butane and condensate. To separate them into more valuable individual products requires fractionation facilities. Fractionation towers separate a stream of mixed NGL feedstock into specification-grade ethane, propane, butane and condensate products. Distillation is the process used to fractionate NGLs.
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Physical refining removes smells and coloration to produce "refined, bleached and deodorized palm oil" (RBDPO) and free fatty acids, which are used in the manufacture of soaps, washing powder and other products. RBDPO is the basic palm oil product sold on the world's commodity markets. Many companies fractionate it further to produce palm oil for cooking oil, or process it into other products.
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The Blank Slate. New York: Penguin. 2002. Critically, multivariate studies show that the distinct faculties of the mind, such as memory and reason, fractionate along genetic boundaries. Cultural universals such as emotion and the relative resilience of psychological adaptation to accidental biological changes (for instance the David Reimer case of gender reassignment following an accident) also support basic biological mechanisms in the mind.
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Higher molecular weights were reported when dry air was bubbled through the reaction mixture during polymerization. Exhaustive Soxhlet extraction after polymerization with polar solvents was found to effectively fractionate the polymer and remove residual catalyst before NMR spectroscopy. Using a lower ratio of catalyst to monomer (2:1, rather than 4:1) may increase the regioregularity of poly(3-dodecylthiophene)s. Andreani et al.
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In nature, variations in isotopic ratios of trace metals on the order of a few tenths to several ‰ are observed within and across diverse environments spanning the geosphere, hydrosphere and biosphere. A complete understanding of all processes that fractionate trace metal isotopes is presently lacking, but in general, isotopes of trace metals are fractionated during various chemical and biological processes due to kinetic and equilibrium isotope effects.
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Leoppky, Bingham, and Sitter (2006) used complete search methodology and have listed the best RPDs for 12, 16, and 20 runs. Because complete search work is so exhaustive, the best designs for larger run sizes are often not readily available. In that case, other statistical methods may be used to fractionate a Hadamard matrix in such a way that allows only a tolerable amount of aliasing.
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Ribosome-binding protein 1, also referred to as p180, is a protein that in humans is encoded by the RRBP1 gene. RRBP1 is a membrane-bound protein found in the endoplasmic reticulum (ER). It was originally identified as the ribosome receptor for the ER, however several groups later demonstrated that this activity did not co-fractionate with RRBP1 but rather with Sec61 (i.e. the translocon).
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Fractional distillation is the separation of a mixture into its component parts, or fractions. Chemical compounds are separated by heating them to a temperature at which one or more fractions of the mixture will vaporize. It uses distillation to fractionate. Generally the component parts have boiling points that differ by less than 25 °C (45 °F) from each other under a pressure of one atmosphere.
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Consistency in measuring the same tissues is also important, as different tissues fractionate deuterium differently. In aquatic systems, tracking trophic interactions is valuable for not only understanding the ecology of the system, but also for determining the degree of terrestrial input. The patterns of deuterium enrichment consistent within trophic levels is a useful tool for assessing the nature of these interactions in the environment.
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A number of common processes fractionate hydrogen isotopes to produce the isotope variations found in nature. Common physical processes include precipitation and evaporation. Chemical reactions also have the potential to heavily influence the partitioning of heavy and light isotopes between pools. The rate of a chemical reaction depends in part on the energies of the chemical bonds being formed and broken in the reaction.
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Isotopic mass balance calculations have implied that sulfate reduction and anaerobic oxidation of methane can fractionate sulfur. During sulfate reductions, the extent of sulfur fractionation varies depending on the environment and rates of reduction. Slower reduction rates lead to higher fractionations and sulfate concentration below 1 mM lead to lower fractionations. The production and consumption of methane leads to archaeal and bacterial highly depleted in 13C biomarkers, specifically lipids.
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If the end-goal of the work at hand is to identify which one(s) of the scores or hundreds of compounds are responsible for the observed in vitro activity, the path to that end is fairly straightforward: # fractionate the crude extract, e.g. by solvent partitioning or chromatography. # test the fractions thereby generated with in vitro assay. # repeat steps 1) and 2) until pure, active compounds are obtained.
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Ignacy Łukasiewicz improved Gesner's method to develop a means of refining kerosene from the more readily available "rock oil" ("petr-oleum") seeps in 1852 and the first rock oil mine was built in Bóbrka, near Krosno in Galicia in the following year. In 1854, Benjamin Silliman, a science professor at Yale University in New Haven, was the first to fractionate petroleum by distillation. These discoveries rapidly spread around the world.
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Although bulk materials differentiate outward or inward according to their density, the elements that are chemically bound in them fractionate according to their chemical affinities, "carried along" by more abundant materials with which they are associated. For instance, although the rare element uranium is very dense as a pure element, it is chemically more compatible as a trace element in the Earth's light, silicate-rich crust than in the dense metallic core.
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While lithium is created in stars during stellar nucleosynthesis, it is further burned. 7Li can also be generated in carbon stars. Lithium isotopes fractionate substantially during a wide variety of natural processes, including mineral formation (chemical precipitation), metabolism, and ion exchange. Lithium ions substitute for magnesium and iron in octahedral sites in clay minerals, where 6Li is preferred to 7Li, resulting in enrichment of the light isotope in processes of hyperfiltration and rock alteration.
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The supercritical solvent is passed into a vessel at lower pressure than the extraction vessel. The density, and hence dissolving power, of supercritical fluids varies sharply with pressure, and hence the solubility in the lower density CO2 is much lower, and the material precipitates for collection. It is possible to fractionate the dissolved material using a series of vessels at reducing pressure. The CO2 can be recycled or depressurized to atmospheric pressure and vented.
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Extraction using superheated water tends to be fast because diffusion rates increase with temperature. Organic materials tend to increase in solubility with temperature, but not all at the same rate. For example, in extraction of essential oils from rosemary and coriander, the more valuable oxygenated terpenes were extracted much faster than the hydrocarbons. Therefore, extraction with superheated water can be both selective and rapid, and has been used to fractionate diesel and woodsmoke particulates.
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Hydrogen sulfide is also present in some parts of the deep ocean where it is released from hydrothermal vents. Both sulfate and sulfide can be used by specialized microbes to obtain energy or to grow. Gases including sulfur dioxide and carbonyl sulfide make up the atmospheric component of the sulfur cycle. Any process that transports or chemically transforms sulfur between these many natural materials also has the potential to fractionate sulfur isotopes.
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Biological deuterium fractionation through metabolism is very organism and pathway dependent, resulting in a wide variability in fractionations. Despite this, some trends still hold. Hydrogen isotopes tend to fractionate very strongly in autotrophs relative to heterotrophs during lipid biosynthesis - chemoautotrophs produce extremely depleted lipids, with the fractionation ranging from roughly −200 to −400‰. This has been observed both in laboratory-grown cultures fed a known quantity of deuterated water and in the environment.
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Another disadvantage to K–Ca dating is that the isotopic composition of calcium (40Ca compared to 42Ca) is difficult to determine using mass spectrometry. Calcium is not easily ionized using a thermoionic source, and tends to isotopically fractionate during ionization. As such, this dating method does not yield satisfactory results unless performed with extremely high precision. Until recently, K–Ca dating was not considered useful for samples younger than the Precambrian, with extremely depleted Ca to K ratios.
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An electrophoresis experiment example: Two conical electrodes are set at both the inlet and outlet of a microchannel and cells are moved along the microchannel by an applied DC electric field. Electrokinetics have been exploited in bio-MEMS for separating mixtures of molecules and cells using electrical fields. In electrophoresis, a charged species in a liquid moves under the influence of an applied electric field. Electrophoresis has been used to fractionate small ions, charged organic molecules, proteins, and DNA.
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Winterization of oil is a process that uses a solvent and cold temperatures to separate lipids and other desired oil compounds from waxes. Winterization is a type of fractionation (also known as fractionate crystallization), the general process of separating the triglycerides found in fats and oils, using the difference in their melting points, solubility, and volatility. Winterization is an oil refinement technique commonly used in biotechnology. The process involves dissolving the extract in ethanol, then placing the mixture in a freezer to chill.
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Moreover, oil is also affected by the isotope fractionation from phase-change. However, the behavior of oil gas-liquid fractionation differs from water as the vapor phase of oil is enriched in D. This will deplete residual oil as it gets evaporated. Biological degradation of oil is also expected to fractionate hydrogen isotopes, as enzymatic breaking of C-H bond have a normal kinetic isotope effect. Several degradation experiments show that this fractionation is generally mild, ranging from −11‰ to −79‰.
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A number of microbial metabolisms fractionate sulfur isotopes in distinctive ways, and the sulfur isotopic fingerprints of these metabolisms can be preserved in minerals and ancient organic matter. By measuring the sulfur isotopic composition of these preserved materials, scientists can reconstruct ancient biological processes and the environments where they occurred. δ34S values in the geologic record have been inferred to reveal the history of microbial sulfate reduction and sulfide oxidation. Paired δ34S and Δ33S records have also been used to show ancient microbial sulfur disproportionation.
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If this information does not allow unequivocal identification of the protein, its peptides can be subject to tandem mass spectrometry for de novo sequencing. Small changes in mass and charge can be detected with 2D-PAGE. The disadvantages with this technique are its small dynamic range compared to other methods, some proteins are still difficult to separate due to their acidity, basicity, hydrophobicity, and size (too large or too small). The second method, high performance liquid chromatography is used to fractionate peptides after enzymatic digestion.
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All three minerals preferentially fractionate Y, yet they form and break down at different stages of metamorphism. Xenotime has the highest fractionating power, then garnet and then monazite. In a simplified case of a clockwise P-T path involving garnet and monazite, garnet grows along a prograde path with Y continuously being incorporated, thus the Y content in monazite formed at this stage (prograde) should decrease progressively with higher grade. However, as temperature increases to a certain point, partial melting (anatectic) of monazite occurs around its rim, releasing Y into the melts.
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Miwi is expressed in various stages of spermatocyte formation and spermatid elongation where Miwi2 is expressed in Sertoli cells. Mice deficient in either Mili or Miwi-2 have experienced spermatogenic stem cell arrest and those lacking Miwi-2 underwent a degradation of spermatogonia. The effects of piwi proteins in human and mouse germlines seems to stem from their involvement in translation control as Piwi and the small noncoding RNA, piwi-interacting RNA (piRNA), have been known to co-fractionate polysomes. The piwi-piRNA pathway also induces heterochromatin formation at centromeres, thus affecting transcription.
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Particles experiencing repulsive and weak attractive DEP forces are eluted by fluid flow, whereas particles experiencing strong attractive DEP forces are trapped at electrode edges against flow drag. Dielectrophoresis field-flow fractionation (DEP-FFF), introduced by Davis and Giddings, is a family of chromatographic-like separation methods. In DEP-FFF, DEP forces are combined with drag flow to fractionate a sample of different types of particles. Particles are injected into a carrier flow that passes through the separation chamber, with an external separating force (a DEP force) being applied perpendicular to the flow.
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The trifid cipher is a classical cipher invented by Félix Delastelle and described in 1902.Delastelle, pp. 101–3. Extending the principles of Delastelle's earlier bifid cipher, it combines the techniques of fractionation and transposition to achieve a certain amount of confusion and diffusion: each letter of the ciphertext depends on three letters of the plaintext and up to three letters of the key. The trifid cipher uses a table to fractionate each plaintext letter into a trigram,Hence the name trifid, which means "divided into three parts" (Oxford English Dictionary).
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For example, he would often give public demonstrations of the blood fractionation machine, in which he would fractionate his own blood on the stage during the lecture. In one such lecture, at the Instituto Superior Técnico in Lisbon, the machine became blocked (without Cohn's knowledge) and exploded, showering the first few rows of the audience with Cohn's blood. Cohn maintained his sangfroid, however, and continued his lecture without significant interruption. More generally, Cohn drove himself relentlessly and ignored his doctors' advice to cut back on working because of his high blood pressure (which finally killed him).
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To provide maximum benefit from each blood donation and to extend shelf-life, blood banks fractionate some whole blood into several products. The most common of these products are packed RBCs, plasma, platelets, cryoprecipitate, and fresh frozen plasma (FFP). FFP is quick-frozen to retain the labile clotting factors V and VIII, which are usually administered to patients who have a potentially fatal clotting problem caused by a condition such as advanced liver disease, overdose of anticoagulant, or disseminated intravascular coagulation (DIC). Units of packed red cells are made by removing as much of the plasma as possible from whole blood units.
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There were also attempts to fractionate synthetic high polymers; however, it was not until 1964, when J. C. Moore of the Dow Chemical Company published his work on the preparation of gel permeation chromatography (GPC) columns based on cross-linked polystyrene with controlled pore size, that a rapid increase of research activity in this field began. It was recognized almost immediately that with proper calibration, GPC was capable to provide molar mass and molar mass distribution information for synthetic polymers. Because the latter information was difficult to obtain by other methods, GPC came rapidly into extensive use.
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ADFGVX was cryptanalysed by French Army Lieutenant Georges Painvin, and the cipher was broken in early June 1918. The work was exceptionally difficult by the standards of classical cryptography, and Painvin became physically ill during it. His method of solution relied on finding messages with stereotyped beginnings, which would fractionate them and then form similar patterns in the positions in the ciphertext that had corresponded to column headings in the transposition table. (Considerable statistical analysis was required after that step had been reached, all done by hand.) It was thus effective only during times of very high traffic, but that was also when the most important messages were sent.
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Sulfate-reducing bacteria metabolize 32S more readily than 34S, resulting in an increase in the value of the δ34S in the remaining sulfate in the seawater. Archean pyrite found in barite in the Warrawoona Group, Western Australia, with sulfur fractionations as great as 21.1‰ hint at the presence of sulfate-reducers as early as . The δ34S value, recorded by sulfate in marine evaporites, can be used to chart the sulfur cycle throughout earth's history. The Great Oxygenation Event around altered the sulfur cycle radically, as increased atmospheric oxygen permitted an increase in the mechanisms that could fractionate sulfur isotopes, leading to an increase in the δ34S value from ~0‰ pre-oxygenation.
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Carbon on Earth naturally occurs in two stable isotopes, with 98.9% in the form of 12C and 1.1% in 13C. The ratio between these isotopes varies in biological organisms due to metabolic processes that selectively use one carbon isotope over the other, or "fractionate" carbon through kinetic or thermodynamic effects. Oxygenic photosynthesis takes place in plants and microorganisms through different chemical pathways, so various forms of organic material reflect different ratios of 13C isotopes. Understanding these variations in carbon fractionation across species is applied in isotope geochemistry and ecological isotope studies to understand biochemical processes, establish food chains, or model the carbon cycle through geological time.
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As the primary moisture source to the atmosphere, the ocean has a relatively uniform hydrogen isotope composition across the globe around 0‰ (VSMOW). Variations of δD larger than 10‰ in the ocean are generally confined to surface waters due to evaporation, sea ice formation, and addition of meteoric waters by precipitation, rivers or icebergs. In the hydrological cycle, the two major processes that fractionate hydrogen isotopes from ocean water are evaporation and condensation. It should be pointed out that oxygen isotopic composition (18O/16O) of water is also an important tracer in the hydrological cycle, and cannot be separated from hydrogen isotopes when we talk about isotope fractionation processes associated with water.
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A high salt concentration, which can be achieved by adding or increasing the concentration of ammonium sulfate in a solution, enables protein separation based on a decrease in protein solubility; this separation may be achieved by centrifugation. Precipitation by ammonium sulfate is a result of a reduction in solubility rather than protein denaturation, thus the precipitated protein can be solubilized through the use of standard buffers. Ammonium sulfate precipitation provides a convenient and simple means to fractionate complex protein mixtures. In the analysis of rubber lattices, volatile fatty acids are analyzed by precipitating rubber with a 35% ammonium sulfate solution, which leaves a clear liquid from which volatile fatty acids are regenerated with sulfuric acid and then distilled with steam.
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Some small Archean evaporite deposits require that at least locally elevated concentrations (possibly due to local volcanic activity) of sulfate existed in order for them to be supersaturated and precipitate out of solution. 3.8–3.6 Ga marks the beginning of the exposed geologic record because this is the age of the oldest rocks on Earth. Metasedimentary rocks from this time still have an isotopic value of 0 because the biosphere was not developed enough (possibly at all) to fractionate sulfur. 3.5 Ga anoxyogenic photosynthesis is established and provides a weak source of sulfate to the global ocean with sulfate concentrations incredibly low the δ34S is still basically 0. Shortly after, at 3.4 Ga the first evidence for minimal fractionation in evaporitic sulfate in association with magmatically derived sulfides can be seen in the rock record.
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All kinetic and equilibrium isotope effects result from differences in atomic mass. As a result, a reaction that fractionates 34S will also fractionate 33S and 36S, and the fractionation factor for each isotope will be mathematically proportional to its mass. Because of the mathematical relationships of their masses, the observed relationships between δ34S, δ33S, and δ36S in most natural materials are approximately δ33S = 0.515 × δ34S and δ36S = 1.90 × δ34S. Rarely, natural processes can create deviations from this relationship, and these deviations are reported as Δ33S and Δ36S values, usually pronounced as "cap delta." These values are typically calculated as follows: Δ33S = 1000 × [(1 + δ33S/1000) - (1 + δ34S 1000)0.518 \- 1] Δ36S = 1000 × [(1 + δ36S/1000) − (1 + δ34S/1000)1.91 − 1] However, the method for calculating Δ33S and Δ36S values is not standardized, and can differ among publications.
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On 9 April, the Government announced the launch of an economic bonus for those workers affected by the COVID-19 pandemic. The bonus varies between ₡125,000 (US$215) per month for people laid off or with a workday reduced to 50% or more, and ₡62,500 (US$108) per month for those who have reduced their workday by 50% or less. The first week of April, the Clodomiro Picado Research Institute of the University of Costa Rica, together with the Costa Rican Social Security Fund, announced the initiative that they were preparing a treatment for the new coronavirus from the blood donated by people whom recovered from COVID-19. Three options were announced; the first would refer to using convalescent plasma, which is to take blood from a recovered patient to fractionate from their plasma the part where the antibodies that released the virus are found and transfuse to a patient who is COVID-19 positive.
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Famous herbalist of the Western tradition include Avicenna (Persian), Galen (Roman), Paracelsus (German Swiss), Culpepper (English) and the botanically inclined Eclectic physicians of 19th century/early 20th century America (John Milton Scudder, Harvey Wickes Felter, John Uri Lloyd). Modern pharmaceuticals had their origins in crude herbal medicines, and to this day, some drugs are still extracted as fractionate/isolate compounds from raw herbs and then purified to meet pharmaceutical standards. There is a record dated 1226 for '12d for Roses for Baron's Chamber and in 1516 for flowers and rushes for chambers for henry the 9th Certain herbs contain psychoactive properties that have been used for both religious and recreational purposes by humans since the early Holocene era, notably the leaves and extracts of the cannabis and coca plants. The leaves of the coca plant have been chewed by people in northern Peruvian societies for over 8,000 years, while the use of cannabis as a psychoactive substance dates back to the first century CE in China and northern Africa.
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