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Titration curve Titrations are often recorded on graphs called titration curves, which generally contain the volume of the titrant as the independent variable and the pH of the solution as the dependent variable (because it changes depending on the composition of the two solutions). The equivalence point on the graph i... | https://en.wikipedia.org/wiki?curid=577830 |
Titration curve Therefore, the Henderson-Hasselbalch equation can be solved in this manner: Therefore, one can easily find the pK of the monoprotic acid by finding the pH of the point halfway between the beginning of the curve and the equivalence point, and solving the simplified equation. In the case of the sample cur... | https://en.wikipedia.org/wiki?curid=577830 |
Redox titration A redox titration is a type of titration based on a redox reaction between the analyte and titrant. It may involve the use of a redox indicator and/or a potentiometer. A common example of a redox titration is treating a solution of iodine with a reducing agent to produce iodide using a starch indicator ... | https://en.wikipedia.org/wiki?curid=577846 |
Redox indicator A redox indicator (also called an oxidation-reduction indicator) is an indicator which undergoes a definite color change at a specific electrode potential. The requirement for fast and reversible color change means that the oxidation-reduction equilibrium for an indicator redox system needs to be establ... | https://en.wikipedia.org/wiki?curid=577876 |
Chromate and dichromate Chromate salts contain the chromate anion, . Dichromate salts contain the dichromate anion, . They are oxoanions of chromium in the 6+ oxidation state and are moderately strong oxidizing agents. In an aqueous solution, chromate and dichromate ions can be interconvertible. Chromates react with hy... | https://en.wikipedia.org/wiki?curid=577881 |
Chromate and dichromate The red line on the predominance diagram is not quite horizontal due to the simultaneous equilibrium with the chromate ion. The hydrogen chromate ion may be protonated, with the formation of molecular chromic acid, HCrO, but the p"K" for the equilibrium is not well characterized. Reported values... | https://en.wikipedia.org/wiki?curid=577881 |
Chromate and dichromate The primary chromium ore is the mixed metal oxide chromite, FeCrO, found as brittle metallic black crystals or granules. Chromite ore is heated with a mixture of calcium carbonate and sodium carbonate in the presence of air. The chromium is oxidized to the hexavalent form, while the iron forms i... | https://en.wikipedia.org/wiki?curid=577881 |
Complexometric titration (sometimes chelatometry) is a form of volumetric analysis in which the formation of a colored complex is used to indicate the end point of a titration. Complexometric titrations are particularly useful for the determination of a mixture of different metal ions in solution. An indicator capable ... | https://en.wikipedia.org/wiki?curid=577908 |
Complexometric titration Note that the shorthand form NaHY can be used to represent any species of EDTA, with x designating the number of acidic protons bonded to the EDTA molecule. EDTA forms an octahedral complex with most 2+ metal cations, M, in aqueous solution. The main reason that EDTA is used so extensively in t... | https://en.wikipedia.org/wiki?curid=577908 |
Half-cell In electrochemistry, a half-cell is a structure that contains a conductive electrode and a surrounding conductive electrolyte separated by a naturally occurring Helmholtz double layer. Chemical reactions within this layer momentarily pump electric charges between the electrode and the electrolyte, resulting i... | https://en.wikipedia.org/wiki?curid=577962 |
Hypochlorous acid (HOCl) is a weak acid that forms when chlorine dissolves in water, and itself partially dissociates, forming hypochlorite, ClO. HClO and ClO are oxidizers, and the primary disinfection agents of chlorine solutions. HClO cannot be isolated from these solutions due to rapid equilibration with its precur... | https://en.wikipedia.org/wiki?curid=578099 |
Hypochlorous acid The acid can also be prepared by dissolving dichlorine monoxide in water; under standard aqueous conditions, anhydrous hypochlorous acid is currently impossible to prepare due to the readily reversible equilibrium between it and its anhydride: The presence of light or transition metal oxides of copper... | https://en.wikipedia.org/wiki?curid=578099 |
Hypochlorous acid One sulfhydryl-containing amino acid can scavenge up to four molecules of HOCl. Consistent with this, it has been proposed that sulfhydryl groups of sulfur-containing amino acids can be oxidized a total of three times by three HClO molecules, with the fourth reacting with the α-amino group. The first ... | https://en.wikipedia.org/wiki?curid=578099 |
Hypochlorous acid Consistent with these results, it was later proposed that the chloramine undergoes a molecular rearrangement, releasing HCl and ammonia to form an aldehyde. The aldehyde group can further react with another amino group to form a Schiff base, causing cross-linking and aggregation of proteins. reacts sl... | https://en.wikipedia.org/wiki?curid=578099 |
Hypochlorous acid reacts with unsaturated bonds in lipids, but not saturated bonds, and the ClO ion does not participate in this reaction. This reaction occurs by hydrolysis with addition of chlorine to one of the carbons and a hydroxyl to the other. The resulting compound is a chlorohydrin. The polar chlorine disrupts... | https://en.wikipedia.org/wiki?curid=578099 |
Hypochlorous acid Later studies have shown that, at bacteriocidal levels, the cytosol components do not react with HOCl. In agreement with this, McFeters and Camper found that aldolase, an enzyme that Knox "et al." proposes would be inactivated, was unaffected by HOCl in vivo. It has been further shown that loss of sul... | https://en.wikipedia.org/wiki?curid=578099 |
Hypochlorous acid One way of addressing the loss of oxygen uptake was by studying the effects of HOCl on succinate-dependent electron transport. Rosen "et al." found that levels of reductable cytochromes in HOCl-treated cells were normal, and these cells were unable to reduce them. Succinate dehydrogenase was also inhi... | https://en.wikipedia.org/wiki?curid=578099 |
Hypochlorous acid The conclusion was that exposed cells have lost the ability to regulate their adenylate pool, based on the fact that metabolite uptake was only 45% deficient after exposure to HOCl and the observation that HOCl causes intracellular ATP hydrolysis. It was also confirmed that, at bacteriocidal levels of... | https://en.wikipedia.org/wiki?curid=578099 |
Hypochlorous acid " compared the rate of HOCl inhibition of DNA replication of plasmids with different replication origins and found that certain plasmids exhibited a delay in the inhibition of replication when compared to plasmids containing oriC. Rosen’s group proposed that inactivation of membrane proteins involved ... | https://en.wikipedia.org/wiki?curid=578099 |
Hypochlorous acid In acid conditions the solution produced will have a high hypochlorous acid concentration, but will also contain dissolved gaseous chlorine, which can be corrosive, at a neutral pH the solution will be around 75% hypochlorous acid and 25% hypochlorite. Some of the chlorine gas produced will dissolve f... | https://en.wikipedia.org/wiki?curid=578099 |
Acetone peroxide (also called APEX) is an organic peroxide and a primary high explosive. It is produced by the reaction of acetone and hydrogen peroxide to yield a mixture of linear monomer and cyclic dimer, trimer, and tetramer forms. The trimer is known as triacetone triperoxide (TATP) or tri-cyclic acetone peroxide ... | https://en.wikipedia.org/wiki?curid=578412 |
Acetone peroxide They found that the trimer could be prepared by adding hydrochloric acid to a chilled mixture of acetone and hydrogen peroxide. By using the depression of freezing points to determine the molecular weights of the compounds, they also determined that the form of acetone peroxide that they had prepared v... | https://en.wikipedia.org/wiki?curid=578412 |
Acetone peroxide This product contains very little or none of DADP with some very small traces of chlorinated compounds. Product that contains large fraction of DADP can be obtained from 50% HO using high amounts of conc. sulfuric acid as catalyst or alternatively with 30% HO and massive amounts of HCl as a catalyst. T... | https://en.wikipedia.org/wiki?curid=578412 |
Acetone peroxide The authors of the 2004 Dubnikova et al. study confirm that a final redox reaction (combustion) of ozone, oxygen and reactive species into water, various oxides and hydrocarbons takes place within about 180 ps after the initial reaction - within about a micron of the detonation wave. Detonating crystal... | https://en.wikipedia.org/wiki?curid=578412 |
Acetone peroxide Ketone peroxides, including acetone peroxide and methyl ethyl ketone peroxide, find application as initiators for polymerization reactions, e.g., silicone or polyester resins, in the making of fiberglass-reinforced composites. For these uses, the peroxides are typically in the form of a dilute solution... | https://en.wikipedia.org/wiki?curid=578412 |
Acetone peroxide It was one of the explosives used by the "shoe bomber" Richard Reid in his 2001 failed shoe bomb attempt and was used by the suicide bombers in the November 2015 Paris attacks, 2016 Brussels bombings, Manchester Arena bombing, June 2017 Brussels attack, Parsons Green bombing, the Surabaya bombings, and... | https://en.wikipedia.org/wiki?curid=578412 |
Acetone peroxide A key disadvantage is the high susceptibility of TATP to accidental detonation, causing workplace accidents and "own goals" among illegal bomb-makers, which has led to TATP being referred to as the "Mother of Satan". TATP was found in the accidental explosion that preceded the 2017 terrorist attacks in... | https://en.wikipedia.org/wiki?curid=578412 |
Lipotropic compounds are those that help catalyse the breakdown of fat during metabolism in the body. Choline is the major lipotrope in mammals and other known lipotropes are important only insofar as they contribute to the synthesis of choline. A lipotropic nutrient promotes or encourages the export of fat from the li... | https://en.wikipedia.org/wiki?curid=579060 |
Lipotropic Choline assists detoxification reactions in the liver. Though choline can be synthesized from methionine or serine, recent evidence indicates that choline is an essential nutrient. Betaine hydrochloride is a powerful lipotropic and increases gastric acid. Betaine itself (in a non-hydrochloric form, also know... | https://en.wikipedia.org/wiki?curid=579060 |
Beta-Carotene β-Carotene is an organic, strongly colored red-orange pigment abundant in fungi, plants, and fruits. It is a member of the carotenes, which are terpenoids (isoprenoids), synthesized biochemically from eight isoprene units and thus having 40 carbons. Among the carotenes, β-carotene is distinguished by havi... | https://en.wikipedia.org/wiki?curid=579219 |
Beta-Carotene Carotenoid absorption is restricted to the duodenum of the small intestine and dependent on class B scavenger receptor (SR-B1) membrane protein, which is also responsible for the absorption of vitamin E (α-tocopherol). One molecule of β-carotene can be cleaved by the intestinal enzyme "β,β-carotene 15,15'... | https://en.wikipedia.org/wiki?curid=579219 |
Beta-Carotene Since 2001, the US Institute of Medicine uses retinol activity equivalents (RAE) for their Dietary Reference Intakes, defined as follows: 1 µg RE = 1 µg retinol 1 µg RAE = 2 µg all-"trans"-β-carotene from supplements 1 µg RAE = 12 µg of all-"trans"-β-carotene from food 1 µg RAE = 24 µg α-carotene or β-cry... | https://en.wikipedia.org/wiki?curid=579219 |
Beta-Carotene The color of β-carotene is masked by chlorophyll in green leaf vegetables such as spinach, kale, sweet potato leaves, and sweet gourd leaves. Vietnamese gac and crude palm oil have the highest content of β-carotene of any known plant sources, 10 times higher than carrots, for example. However, gac is quit... | https://en.wikipedia.org/wiki?curid=579219 |
Beta-Carotene This mechanism is regulated by the individual's vitamin A status. If the body has enough vitamin A, the conversion of β-carotene decreases. Therefore, β-carotene is considered a safe source of vitamin A and high intakes will not lead to hypervitaminosis A. β-Carotene can interact with medication used for ... | https://en.wikipedia.org/wiki?curid=579219 |
Beta-Carotene A β-carotene breakdown product suspected of causing cancer at high dose is "trans"-β-apo-8'-carotenal (common apocarotenal), which has been found in one study to be mutagenic and genotoxic in cell cultures which do not respond to β-carotene itself. Additionally, supplemental β-carotene may increase the ri... | https://en.wikipedia.org/wiki?curid=579219 |
Beta-Carotene In a single, small clinical study published in 1989, natural beta-carotene appeared to reduce premalignant gastric lesions. A Cochrane review looked at supplementation of β-carotene, vitamin C, and vitamin E, independently and combined, on people to examine differences in risk of cataract, cataract extrac... | https://en.wikipedia.org/wiki?curid=579219 |
Drug design Drug design, often referred to as rational drug design or simply rational design, is the inventive process of finding new medications based on the knowledge of a biological target. The drug is most commonly an organic small molecule that activates or inhibits the function of a biomolecule such as a protein,... | https://en.wikipedia.org/wiki?curid=579414 |
Drug design , that first must be optimized before a ligand can become a safe and efficacious drug. These other characteristics are often difficult to predict with rational design techniques. Nevertheless, due to high attrition rates, especially during clinical phases of drug development, more attention is being focused... | https://en.wikipedia.org/wiki?curid=579414 |
Drug design Small molecules (drugs) can be designed so as not to affect any other important "off-target" molecules (often referred to as antitargets) since drug interactions with off-target molecules may lead to undesirable side effects. Due to similarities in binding sites, closely related targets identified through s... | https://en.wikipedia.org/wiki?curid=579414 |
Drug design This means that it is capable of binding to a small molecule and that its activity can be modulated by the small molecule. Once a suitable target has been identified, the target is normally cloned and produced and purified. The purified protein is then used to establish a screening assay. In addition, the t... | https://en.wikipedia.org/wiki?curid=579414 |
Drug design The most fundamental goal in drug design is to predict whether a given molecule will bind to a target and if so how strongly. Molecular mechanics or molecular dynamics is most often used to estimate the strength of the intermolecular interaction between the small molecule and its biological target. These me... | https://en.wikipedia.org/wiki?curid=579414 |
Drug design The reality is that present computational methods are imperfect and provide, at best, only qualitatively accurate estimates of affinity. In practice it still takes several iterations of design, synthesis, and testing before an optimal drug is discovered. Computational methods have accelerated discovery by r... | https://en.wikipedia.org/wiki?curid=579414 |
Drug design In other words, a model of the biological target may be built based on the knowledge of what binds to it, and this model in turn may be used to design new molecular entities that interact with the target. Alternatively, a quantitative structure-activity relationship (QSAR), in which a correlation between ca... | https://en.wikipedia.org/wiki?curid=579414 |
Drug design The first method is identification of new ligands for a given receptor by searching large databases of 3D structures of small molecules to find those fitting the binding pocket of the receptor using fast approximate docking programs. This method is known as virtual screening. A second category is de novo de... | https://en.wikipedia.org/wiki?curid=579414 |
Drug design In brief, binding site identification usually relies on identification of concave surfaces on the protein that can accommodate drug sized molecules that also possess appropriate "hot spots" (hydrophobic surfaces, hydrogen bonding sites, etc.) that drive ligand binding. Structure-based drug design attempts t... | https://en.wikipedia.org/wiki?curid=579414 |
Drug design According to Gibbs free energy equation, the relation between dissociation equilibrium constant, K, and the components of free energy was built. Various computational methods are used to estimate each of the components of the master equation. For example, the change in polar surface area upon ligand binding... | https://en.wikipedia.org/wiki?curid=579414 |
Drug design This approach to drug discovery is sometimes referred to as structure-based drug design. The first unequivocal example of the application of structure-based drug design leading to an approved drug is the carbonic anhydrase inhibitor dorzolamide, which was approved in 1995. Another important case study in ra... | https://en.wikipedia.org/wiki?curid=579414 |
Methanogenesis or biomethanation is the formation of methane by microbes known as methanogens. Organisms capable of producing methane have been identified only from the domain Archaea, a group phylogenetically distinct from both eukaryotes and bacteria, although many live in close association with anaerobic bacteria. T... | https://en.wikipedia.org/wiki?curid=579750 |
Methanogenesis However, depending on pH and temperature, methanogenesis has been shown to use carbon from other small organic compounds, such as formic acid (formate), methanol, methylamines, tetramethylammonium, dimethyl sulfide, and methanethiol. The catabolism of the methyl compounds is mediated by methyl transferas... | https://en.wikipedia.org/wiki?curid=579750 |
Methanogenesis During the decay process, electron acceptors (such as oxygen, ferric iron, sulfate, and nitrate) become depleted, while hydrogen (H) and carbon dioxide accumulate. Light organics produced by fermentation also accumulate. During advanced stages of organic decay, all electron acceptors become depleted exce... | https://en.wikipedia.org/wiki?curid=579750 |
Methanogenesis Some humans produce flatus that contains methane. In one study of the feces of nine adults, five of the samples contained archaea capable of producing methane. Similar results are found in samples of gas obtained from within the rectum. Even among humans whose flatus does contain methane, the amount is i... | https://en.wikipedia.org/wiki?curid=579750 |
Methanogenesis It may not be a net contributor in the sense that it works on organic material which used up atmospheric carbon dioxide when it was created, but its overall effect is to convert the carbon dioxide into methane which is a much more potent greenhouse gas. can also be beneficially exploited, to treat organi... | https://en.wikipedia.org/wiki?curid=579750 |
Methanogenesis On 13 April 2017, NASA confirmed that the dive of the Cassini orbiter spacecraft on 28 October 2015 discovered the Enceladus plume which has all the ingredients for methanogenesis-based life forms to feed from. Previous results, published in March 2015, suggested hot water is interacting with rock beneat... | https://en.wikipedia.org/wiki?curid=579750 |
Gay-Lussac's law (more correctly referred to as Amontons's law) states that the pressure of a given mass of gas varies directly with the absolute temperature of the gas, when the volume is kept constant. Mathematically, it can be written as: formula_1. Gay-Lussac is incorrectly recognized for the Pressure Law which est... | https://en.wikipedia.org/wiki?curid=580069 |
Gay-Lussac's law This hypothesis meant that the previously stated result could also be expressed as The law of combining gases was made public by Joseph Louis Gay-Lussac in 1808. Avogadro's hypothesis, however, was not initially accepted by chemists until the Italian chemist Stanislao Cannizzaro was able to convince th... | https://en.wikipedia.org/wiki?curid=580069 |
Gay-Lussac's law Some introductory physics textbooks still define the pressure-temperature relationship as Gay-Lussac's law. Gay-Lussac primarily investigated the relationship between volume and temperature and published it in 1802, but his work did cover some comparison between pressure and temperature. Given the rela... | https://en.wikipedia.org/wiki?curid=580069 |
Sulfur trioxide (alternative spelling sulphur trioxide) is the chemical compound with the formula SO, with a relatively narrow liquid range. In the gaseous form, this species is a significant pollutant, being the primary agent in acid rain. It is prepared on an industrial scale as a precursor to sulfuric acid, and is a... | https://en.wikipedia.org/wiki?curid=580936 |
Sulfur trioxide SO is a strong Lewis acid readily forming crystalline complexes with pyridine, dioxane, and trimethylamine. These adducts can be used as sulfonating agents. The direct oxidation of sulfur dioxide to sulfur trioxide in air: does take place, but at 298 K has a ΔG = -141.6 kJ and ΔS = -187.9 J/K, so the re... | https://en.wikipedia.org/wiki?curid=580936 |
Sulfur trioxide is generated in situ from sulfuric acid or is used as a solution in the acid. The nature of solid SO is complex because structural changes are caused by traces of water. Upon condensation of the gas, absolutely pure SO condenses into a trimer, which is often called "γ"-SO. This molecular form is a color... | https://en.wikipedia.org/wiki?curid=580936 |
Sulfur trioxide In such cases, SO dehydrates these carbohydrates. Along with being a strong oxidizing agent, sulfur trioxide will cause serious burns on both inhalation and ingestion because it is highly corrosive and hygroscopic in nature. SO should be handled with extreme care as it reacts violently with water and pr... | https://en.wikipedia.org/wiki?curid=580936 |
Acyl chloride In organic chemistry, an acyl chloride (or acid chloride) is an organic compound with the functional group -COCl. Their formula is usually written RCOCl, where R is a side chain. They are reactive derivatives of carboxylic acids. A specific example of an acyl chloride is acetyl chloride, CHCOCl. Acyl chlo... | https://en.wikipedia.org/wiki?curid=581370 |
Acyl chloride The industrial route to acetyl chloride involves the reaction of acetic anhydride with hydrogen chloride: Propionyl chloride is produced by chlorination of propionic acid with phosgene: Benzoyl chloride is produced by the partial hydrolysis of benzotrichloride: In the laboratory, acyl chlorides are genera... | https://en.wikipedia.org/wiki?curid=581370 |
Acyl chloride Finally, methods that do not form HCl are also known, such as the Appel reaction: and the use of cyanuric chloride (CNCl): Acyl chlorides react with water yielding the carboxylic acid: Acyl chlorides are used to prepare acid anhydrides, esters, and amides by reacting acid chlorides with: a salt of a carbo... | https://en.wikipedia.org/wiki?curid=581370 |
Acyl chloride Acid chlorides of aromatic acids are generally less reactive those of alkyl acids and thus somewhat more rigorous conditions are required for reaction. Acyl chlorides are reduced by lithium aluminium hydride and diisobutylaluminium hydride to give primary alcohols. Lithium tri-tert-butoxyaluminium hydride... | https://en.wikipedia.org/wiki?curid=581370 |
Table of standard reduction potentials for half-reactions important in biochemistry The values below are standard reduction potentials for half-reactions measured at 25°C, 1 atmosphere and a pH of 7 in aqueous solution. | https://en.wikipedia.org/wiki?curid=581417 |
Rabi cycle In physics, the (or Rabi flop) is the cyclic behaviour of a two-level quantum system in the presence of an oscillatory driving field. A great variety of physical processes belonging to the areas of quantum computing, condensed matter, atomic and molecular physics, and nuclear and particle physics can be conv... | https://en.wikipedia.org/wiki?curid=582228 |
Rabi cycle More generally, one can consider a system where the two levels under consideration are not energy eigenstates. Therefore, if the system is initialized in one of these levels, time evolution will make the population of each of the levels oscillate with some characteristic frequency, whose angular frequency is... | https://en.wikipedia.org/wiki?curid=582228 |
Rabi cycle This matrix can be decomposed as, The matrix formula_23 is the 2 formula_12 2 identity matrix and the matrices formula_25 are the Pauli matrices. This decomposition simplifies the analysis of the system especially in the time-independent case where the values of formula_26and formula_21are constants. Conside... | https://en.wikipedia.org/wiki?curid=582228 |
Rabi cycle So in this case the probability of finding spin-up in x-direction is oscillatory in time formula_53 when the system's spin is initially in the formula_41 direction. Similarly, if we measure the spin in the formula_55-direction, the probability of measuring spin as formula_56 of the system is formula_57. In t... | https://en.wikipedia.org/wiki?curid=582228 |
Hydraulic diameter The hydraulic diameter, , is a commonly used term when handling flow in non-circular tubes and channels. Using this term, one can calculate many things in the same way as for a round tube. It is defined as where More intuitively, the hydraulic diameter can be understood as a function of the hydraulic... | https://en.wikipedia.org/wiki?curid=582273 |
Beam splitter A beam splitter (or beamsplitter) is an optical device that splits a beam of light in two. It is a crucial part of many optical experimental and measurement systems, such as interferometers, also finding widespread application in fibre optic telecommunications. In its most common form, a cube, it is made ... | https://en.wikipedia.org/wiki?curid=582410 |
Beam splitter To reduce loss of light due to absorption by the reflective coating, so-called "swiss cheese" beam splitter mirrors have been used. Originally, these were sheets of highly polished metal perforated with holes to obtain the desired ratio of reflection to transmission. Later, metal was sputtered onto glass ... | https://en.wikipedia.org/wiki?curid=582410 |
Beam splitter The splitter is done by physically splicing two fibers "together" as an X. Arrangements of mirrors or prisms used as camera attachments to photograph stereoscopic image pairs with one lens and one exposure are sometimes called "beam splitters", but that is a misnomer, as they are effectively a pair of per... | https://en.wikipedia.org/wiki?curid=582410 |
Beam splitter The behavior is dictated by the Fresnel equations. This does not apply to partial reflection by conductive (metallic) coatings, where other phase shifts occur in all paths (reflected and transmitted). In any case, the details of the phase shifts depend on the type and geometry of the beam splitter. For be... | https://en.wikipedia.org/wiki?curid=582410 |
Beam splitter Then is obtained Further simplifying, the relationship becomes which is true when formula_9 and the exponential term reduces to -1. Applying this new condition and squaring both sides, it becomes where substitutions of the form formula_11 were made. This leads to the result and similarly, It follows that ... | https://en.wikipedia.org/wiki?curid=582410 |
Beam splitter Assuming the reflected beam suffers a formula_24 phase shift, the input and output fields are related by: formula_25 The unitary transformation associated with this transformation is formula_26 Using this unitary, one can also write the transforms as formula_27 In 2000 Knill, Laflamme and Milburn (KLM pro... | https://en.wikipedia.org/wiki?curid=582410 |
Particle number The particle number (or number of particles) of a thermodynamic system, conventionally indicated with the letter "N", is the number of constituent particles in that system. The particle number is a fundamental parameter in thermodynamics which is conjugate to the chemical potential. Unlike most physical... | https://en.wikipedia.org/wiki?curid=582770 |
Particle number A related intensive system parameter is given by the particle number density, obtained by dividing the particle number of a system by its volume. This parameter is often denoted by a lower-case letter "n". In quantum mechanical processes the total number of particles may not be preserved. The concept is... | https://en.wikipedia.org/wiki?curid=582770 |
Transformation (genetics) In molecular biology and genetics, transformation is the genetic alteration of a cell resulting from the direct uptake and incorporation of exogenous genetic material from its surroundings through the cell membrane(s). For transformation to take place, the recipient bacterium must be in a stat... | https://en.wikipedia.org/wiki?curid=583438 |
Transformation (genetics) Transformation in bacteria was first demonstrated in 1928 by the British bacteriologist Frederick Griffith. Griffith was interested in determining whether injections of heat-killed bacteria could be used to vaccinate mice against pneumonia. However, he discovered that a non-virulent strain of ... | https://en.wikipedia.org/wiki?curid=583438 |
Transformation (genetics) coli" may be induced to take up DNA from bacteriophage λ without the use of helper phage after treatment with calcium chloride solution. Two years later in 1972, Stanley Norman Cohen, Annie Chang and Leslie Hsu showed that treatment is also effective for transformation of plasmid DNA. The meth... | https://en.wikipedia.org/wiki?curid=583438 |
Transformation (genetics) tumefaciens", so other methods were developed, including electroporation and micro-injection. Particle bombardment was made possible with the invention of the Biolistic Particle Delivery System (gene gun) by John Sanford in the 1980s. Transformation is one of three forms of horizontal gene tra... | https://en.wikipedia.org/wiki?curid=583438 |
Transformation (genetics) It has also been studied in Gram-negative species found in soil such as "Pseudomonas stutzeri", "Acinetobacter baylyi", and Gram-negative plant pathogens such as "Ralstonia solanacearum" and "Xylella fastidiosa". Transformation among Gram-positive bacteria has been studied in medically importa... | https://en.wikipedia.org/wiki?curid=583438 |
Transformation (genetics) The transport of the exogenous DNA into the cells may require proteins that are involved in the assembly of type IV pili and type II secretion system, as well as DNA translocase complex at the cytoplasmic membrane. Due to the differences in structure of the cell envelope between Gram-positive ... | https://en.wikipedia.org/wiki?curid=583438 |
Transformation (genetics) In order for a bacterium to bind, take up and recombine exogenous DNA into its chromosome, it must become competent, that is, enter a special physiological state. Competence development in "Bacillus subtilis" requires expression of about 40 genes. The DNA integrated into the host chromosome is... | https://en.wikipedia.org/wiki?curid=583438 |
Transformation (genetics) Similarly, in "Micrococcus luteus" (a representative of the less well studied "Actinobacteria" phylum), competence develops during the mid-late exponential growth phase and is also triggered by amino acids starvation. By releasing intact host and plasmid DNA, certain bacteriophages are thought... | https://en.wikipedia.org/wiki?curid=583438 |
Transformation (genetics) Logarithmically growing bacteria differ from stationary phase bacteria with respect to the number of genome copies present in the cell, and this has implications for the capability to carry out an important DNA repair process. During logarithmic growth, two or more copies of any particular reg... | https://en.wikipedia.org/wiki?curid=583438 |
Transformation (genetics) Transformation in bacteria can be viewed as a primitive sexual process, since it involves interaction of homologous DNA from two individuals to form recombinant DNA that is passed on to succeeding generations. Bacterial transformation in prokaryotes may have been the ancestral process that gav... | https://en.wikipedia.org/wiki?curid=583438 |
Transformation (genetics) One function of the divalent cation therefore would be to shield the charges by coordinating the phosphate groups and other negative charges, thereby allowing a DNA molecule to adhere to the cell surface. DNA entry into "E. coli" cells is through channels known as zones of adhesion or Bayer's ... | https://en.wikipedia.org/wiki?curid=583438 |
Transformation (genetics) Several methods have been developed to facilitate this transformation at high frequency in the lab. Efficiency – Different yeast genera and species take up foreign DNA with different efficiencies. Also, most transformation protocols have been developed for baker's yeast, "S. cerevisiae", and t... | https://en.wikipedia.org/wiki?curid=583438 |
Transformation (genetics) In order to be stably maintained in the cell, a plasmid DNA molecule must contain an origin of replication, which allows it to be replicated in the cell independently of the replication of the cell's own chromosome. The efficiency with which a competent culture can take up exogenous DNA and ex... | https://en.wikipedia.org/wiki?curid=583438 |
Transformation (genetics) In contrast, cells that are naturally competent are usually transformed more efficiently with linear DNA than with plasmid DNA. The transformation efficiency using the method decreases with plasmid size, and electroporation therefore may be a more effective method for the uptake of large plasm... | https://en.wikipedia.org/wiki?curid=583438 |
Transformation (genetics) This method requires the use of suitably mutated strains that are deficient in the synthesis or utility of a particular biomolecule, and the transformed cells are cultured in a medium that allows only cells containing the plasmid to grow. In a cloning experiment, a gene may be inserted into a ... | https://en.wikipedia.org/wiki?curid=583438 |
Transformation (genetics) Cells containing successfully ligated insert can then be easily identified by its white coloration from the unsuccessful blue ones. Other commonly used reporter genes are green fluorescent protein (GFP), which produces cells that glow green under blue light, and the enzyme luciferase, which ca... | https://en.wikipedia.org/wiki?curid=583438 |
Oxygen cycle The oxygen cycle is the biogeochemical transitions of oxygen atoms between different oxidation states in ions, oxides, and molecules through redox reactions within and between the spheres/reservoirs of the planet Earth. The word oxygen in the literature typically refers to the most common oxygen allotrope,... | https://en.wikipedia.org/wiki?curid=583598 |
Oxygen cycle The hydrosphere present mainly as a component of water molecules with dissolved molecules including free oxygen and carbonic acids (HCO). The lithosphere is 46.6% oxygen by volume present mainly as silica minerals (SiO) and other oxide minerals. While there are many abiotic sources and sinks for O, the pre... | https://en.wikipedia.org/wiki?curid=583598 |
Oxygen cycle The free H and escape into space, leaving O in the atmosphere: The main way free oxygen is lost from the atmosphere is via respiration and decay, mechanisms in which animal life and bacteria consume oxygen and release carbon dioxide. The following tables offer estimates of oxygen cycle reservoir capacities... | https://en.wikipedia.org/wiki?curid=583598 |
Small interfering RNA (siRNA), sometimes known as short interfering RNA or silencing RNA, is a class of double-stranded RNA non-coding RNA molecules, 20-25 base pairs in length, similar to miRNA, and operating within the RNA interference (RNAi) pathway. It interferes with the expression of specific genes with complemen... | https://en.wikipedia.org/wiki?curid=584617 |
Small interfering RNA This may be overcome by creating an expression vector for the siRNA. The siRNA sequence is modified to introduce a short loop between the two strands. The resulting transcript is a short hairpin RNA (shRNA), which can be processed into a functional siRNA by Dicer in its usual fashion. Typical tran... | https://en.wikipedia.org/wiki?curid=584617 |
Small interfering RNA The siRNA induced post transcriptional gene silencing starts with the assembly of the RNA-induced silencing complex (RISC). The complex silences certain gene expression by cleaving the mRNA molecules coding the target genes. To begin the process, one of the two siRNA strands, the guide strand (ant... | https://en.wikipedia.org/wiki?curid=584617 |
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