text stringlengths 11 1.65k | source stringlengths 38 44 |
|---|---|
Luminous paint or luminescent paint is paint that exhibits luminescence. In other words, it gives off visible light through fluorescence, phosphorescence, or radioluminescence. There are three types of luminous paints. Fluorescent paints offer a wide range of pigments and chroma which also 'glow' when exposed to the lo... | https://en.wikipedia.org/wiki?curid=2331922 |
Luminous paint Invisible fluorescent paints appear transparent or pale under daytime lighting, but will glow under UV light in a limited range of colors. Since these can seem to 'disappear', they can be used to create a variety of clever effects. Both types of fluorescent painting benefit when used within a contrasting... | https://en.wikipedia.org/wiki?curid=2331922 |
Luminous paint Kenner's "Lightning Bug Glo-Juice" was a popular non-toxic paint product in 1968, marketed at children, alongside other glow-in-the-dark toys and novelties. Phosphorescent paint is typically used as body paint, on children's walls and outdoors. When applied as a paint or a more sophisticated coating (e.g... | https://en.wikipedia.org/wiki?curid=2331922 |
Luminous paint Radium paint was widely used for 40 years on the faces of watches, compasses, and aircraft instruments, so they could be read in the dark. Radium is a radiological hazard, emitting gamma rays that can penetrate a glass watch dial and into human tissue. During the 1920s and 1930s, the harmful effects of t... | https://en.wikipedia.org/wiki?curid=2331922 |
Luminous paint The dials can be renovated by application of a very thin layer of fresh phosphor, without the radium content (with the original material still acting as the energy source); the phosphor layer has to be thin due to the light self-absorption in the material. In the second half of the 20th century, radium w... | https://en.wikipedia.org/wiki?curid=2331922 |
Luminous paint They are additionally used in glowing novelty keychains, in self-illuminated exit signs, and formerly in fishing lures. They are favored by the military for applications where a power source may not be available, such as for instrument dials in aircraft, compasses, lights for map reading, and sights for ... | https://en.wikipedia.org/wiki?curid=2331922 |
Iodine pentafluoride is an interhalogen compound with chemical formula IF. It is one of the fluorides of iodine. It is a colorless liquid, although impure samples appear yellow. It is used as a fluorination reagent and even a solvent in specialized syntheses. It was first synthesized by Henri Moissan in 1891 by burning... | https://en.wikipedia.org/wiki?curid=2332188 |
Iodine heptafluoride Iodine heptafluoride, also known as iodine(VII) fluoride or iodine fluoride, is an interhalogen compound with the chemical formula IF. It has an unusual pentagonal bipyramidal structure, as predicted by VSEPR theory. The molecule can undergo a pseudorotational rearrangement called the Bartell mecha... | https://en.wikipedia.org/wiki?curid=2332266 |
Carcinogenesis Carcinogenesis, also called oncogenesis or tumorigenesis, is the formation of a cancer, whereby normal cells are transformed into cancer cells. The process is characterized by changes at the cellular, genetic, and epigenetic levels and abnormal cell division. Cell division is a physiological process that... | https://en.wikipedia.org/wiki?curid=2332422 |
Carcinogenesis On average, for example, 15 "driver mutations" and 60 "passenger" mutations are found in colon cancers. Mutations in genes that regulate cell division, apoptosis (cell death), and DNA repair may result in uncontrolled cell proliferation and cancer. Cancer is fundamentally a disease of regulation of tissu... | https://en.wikipedia.org/wiki?curid=2332422 |
Carcinogenesis Many of these changes are mutations, or changes in the nucleotide sequence of genomic DNA. There are also many epigenetic changes that alter whether genes are expressed or not expressed. Aneuploidy, the presence of an abnormal number of chromosomes, is one genomic change that is not a mutation, and may i... | https://en.wikipedia.org/wiki?curid=2332422 |
Carcinogenesis More than 60,000 new naturally-occurring instances of DNA damage arise, on average, per human cell, per day, due to endogenous cellular processes (see article DNA damage (naturally occurring)). Additional DNA damage can arise from exposure to exogenous agents. As one example of an exogenous carcinogenic ... | https://en.wikipedia.org/wiki?curid=2332422 |
Carcinogenesis A deficiency in DNA repair would cause more DNA damage to accumulate, and increase the risk for cancer. For example, individuals with an inherited impairment in any of 34 DNA repair genes (see article DNA repair-deficiency disorder) are at increased risk of cancer, with some defects causing an up to 100%... | https://en.wikipedia.org/wiki?curid=2332422 |
Carcinogenesis This is shown in the figure at the 4th level from the top. With a DNA repair deficiency, DNA damage persists in cells at a higher than typical level (5th level from the top in figure); this excess damage causes an increased frequency of mutation and/or epimutation (6th level from top of figure). Experime... | https://en.wikipedia.org/wiki?curid=2332422 |
Carcinogenesis Men who currently smoke tobacco develop lung cancer at a rate 14 times that of men who have never smoked tobacco: the chance of lung cancer in a current smoker being caused by smoking is about 93%; there is a 7% chance that the smoker's lung cancer was caused by radon gas or some other, non-tobacco cause... | https://en.wikipedia.org/wiki?curid=2332422 |
Carcinogenesis Other mutations enable the tumor to grow new blood vessels to provide more nutrients, or to metastasize, spreading to other parts of the body. However, once a cancer is formed it continues to evolve and to produce sub-clones. It was reported in 2012 that a single renal cancer specimen, sampled in nine di... | https://en.wikipedia.org/wiki?curid=2332422 |
Carcinogenesis Second, statistics show that most human cancers are diagnosed in older people. A possible explanation is that cancers occur because cells accumulate damage through time. DNA is the only cellular component that can accumulate damage over the entire course of a life, and stem cells are the only cells that ... | https://en.wikipedia.org/wiki?curid=2332422 |
Carcinogenesis It would also be expected that many of the epigenetic alterations present in tumors may have occurred in pre-neoplastic field defects. In the colon, a field defect probably arises by natural selection of a mutant or epigenetically altered cell among the stem cells at the base of one of the intestinal cry... | https://en.wikipedia.org/wiki?curid=2332422 |
Carcinogenesis Within these new patches (sub-clones), the process may be repeated multiple times, indicated by the still smaller patches within the four secondary patches (with still different colors in the diagram) which clonally expand, until stem cells arise that generate either small polyps or else a malignant neop... | https://en.wikipedia.org/wiki?curid=2332422 |
Carcinogenesis The most extensive region of abnormality (the outermost yellow irregular area in the diagram) would reflect the earliest event in formation of a malignant neoplasm. In experimental evaluation of specific DNA repair deficiencies in cancers, many specific DNA repair deficiencies were also shown to occur in... | https://en.wikipedia.org/wiki?curid=2332422 |
Carcinogenesis In an average melanoma tissue sample (melanomas have a higher exome mutation frequency),) the total number of DNA sequence mutations is about 80,000. These high frequencies of mutations in the total nucleotide sequences within cancers suggest that often an early alteration in the field defect giving rise... | https://en.wikipedia.org/wiki?curid=2332422 |
Carcinogenesis Although the mutations/epimutations in DNA repair genes do not, themselves, confer a selective advantage, they may be carried along as passengers in cells when the cell acquires an additional mutation/epimutation that does provide a proliferative advantage. There are a number of theories of carcinogenesi... | https://en.wikipedia.org/wiki?curid=2332422 |
Carcinogenesis A number of authors have questioned the assumption that cancers result from sequential random mutations as oversimplistic, suggesting instead that cancer results from a failure of the body to inhibit an innate, programmed proliferative tendency. A related theory suggests that cancer is an atavism, an evo... | https://en.wikipedia.org/wiki?curid=2332422 |
Carcinogenesis Often, the multiple genetic changes that result in cancer may take many years to accumulate. During this time, the biological behavior of the pre-malignant cells slowly changes from the properties of normal cells to cancer-like properties. Pre-malignant tissue can have a distinctive appearance under the ... | https://en.wikipedia.org/wiki?curid=2332422 |
Carcinogenesis Most changes in cellular metabolism that allow cells to grow in a disorderly fashion lead to cell death. However once cancer begins, cancer cells undergo a process of natural selection: the few cells with new genetic changes that enhance their survival or reproduction multiply faster, and soon come to do... | https://en.wikipedia.org/wiki?curid=2332422 |
Carcinogenesis Rather, a subset of the cells in a tumor, called cancer stem cells, replicate themselves as they generate differentiated cells. Normally, once a tissue is injured or infected, damaged cells elicit inflammation by stimulating specific patterns of enzyme activity and cytokine gene expression in surrounding... | https://en.wikipedia.org/wiki?curid=2332422 |
Carcinogenesis Cancer cells do not communicate with their tissue microenvironment in a manner that protects tissue integrity; instead, the movement and the survival of cancer cells become possible in locations where they can impair tissue function. Cancer cells survive by "rewiring" signal pathways that normally protec... | https://en.wikipedia.org/wiki?curid=2332422 |
Carcinogenesis The role of iodine in marine fishes (rich in iodine) and freshwater fishes (iodine-deficient) is not completely understood, but it has been reported that freshwater fishes are more susceptible to infectious and, in particular, neoplastic and atherosclerotic diseases, than marine fishes. Marine elasmobran... | https://en.wikipedia.org/wiki?curid=2332422 |
Carcinogenesis Oncogenes promote cell growth through a variety of ways. Many can produce hormones, a "chemical messenger" between cells that encourage mitosis, the effect of which depends on the signal transduction of the receiving tissue or cells. In other words, when a hormone receptor on a recipient cell is stimulat... | https://en.wikipedia.org/wiki?curid=2332422 |
Carcinogenesis One of the first oncogenes to be defined in cancer research is the ras oncogene. Mutations in the Ras family of proto-oncogenes (comprising H-Ras, N-Ras and K-Ras) are very common, being found in 20% to 30% of all human tumours. Ras was originally identified in the Harvey sarcoma virus genome, and resear... | https://en.wikipedia.org/wiki?curid=2332422 |
Carcinogenesis It is only when they become mutated that the signals for growth become excessive. It is important to note that a gene possessing a growth-promoting role may increase the carcinogenic potential of a cell, under the condition that all necessary cellular mechanisms that permit growth are activated. This con... | https://en.wikipedia.org/wiki?curid=2332422 |
Carcinogenesis Despite nearly half of all cancers possibly involving alterations in p53, its tumor suppressor function is poorly understood. p53 clearly has two functions: one a nuclear role as a transcription factor, and the other a cytoplasmic role in regulating the cell cycle, cell division, and apoptosis. The Warbu... | https://en.wikipedia.org/wiki?curid=2332422 |
Carcinogenesis Other inherited tumor suppressor gene syndromes include "Rb" mutations, linked to retinoblastoma, and "APC" gene mutations, linked to adenopolyposis colon cancer. Adenopolyposis colon cancer is associated with thousands of polyps in colon while young, leading to colon cancer at a relatively early age. Fi... | https://en.wikipedia.org/wiki?curid=2332422 |
Carcinogenesis Knudson's two hit model has recently been challenged by several investigators. Inactivation of one allele of some tumor suppressor genes is sufficient to cause tumors. This phenomenon is called haploinsufficiency and has been demonstrated by a number of experimental approaches. Tumors caused by haploinsu... | https://en.wikipedia.org/wiki?curid=2332422 |
Carcinogenesis The mode of inheritance of mutant tumor suppressors is that affected member inherits a defective copy from one parent, and a normal copy from another. Because mutations in tumor suppressors act in a recessive manner (note, however, there are exceptions), the loss of the normal copy creates the cancer phe... | https://en.wikipedia.org/wiki?curid=2332422 |
Carcinogenesis These are thought to promote cancers through their stimulating effect on the rate of cell mitosis. Faster rates of mitosis increasingly leave fewer opportunities for repair enzymes to repair damaged DNA during DNA replication, increasing the likelihood of a genetic mistake. A mistake made during mitosis ... | https://en.wikipedia.org/wiki?curid=2332422 |
Carcinogenesis The gastritis caused by "H. pylori" is accompanied by inflammation, characterized by infiltration of neutrophils and macrophages to the gastric epithelium, which favors the accumulation of pro-inflammatory cytokines and reactive oxygen species/reactive nitrogen species (ROS/RNS). The substantial presence... | https://en.wikipedia.org/wiki?curid=2332422 |
Carcinogenesis Dyspepsia occurs in about 20% of infected individuals.. In addition, as reviewed by Raza et al., human gastric infection with "H. pylori" causes epigenetically reduced protein expression of DNA repair proteins MLH1, MGMT and MRE11. Reduced DNA repair in the presence of increased DNA damage increases carc... | https://en.wikipedia.org/wiki?curid=2332422 |
Carcinogenesis Viruses that are known to cause cancer such as HPV (cervical cancer), Hepatitis B (liver cancer), and EBV (a type of lymphoma), are all DNA viruses. It is thought that when the virus infects a cell, it inserts a part of its own DNA near the cell growth genes, causing cell division. The group of changed c... | https://en.wikipedia.org/wiki?curid=2332422 |
Carcinogenesis It would be expected that cells that are damaged through radiation would die or at least be worse off because they have fewer genes working; viruses increase the number of genes working. One thought is that we may end up with thousands of vaccines to prevent every virus that can change our cells. Viruses... | https://en.wikipedia.org/wiki?curid=2332422 |
Carcinogenesis Epimutations include methylations or demethylations of the CpG islands of the promoter regions of genes, which result in repression or de-repression, respectively of gene expression. Epimutations can also occur by acetylation, methylation, phosphorylation or other alterations to histones, creating a hist... | https://en.wikipedia.org/wiki?curid=2332422 |
Carcinogenesis The cancer stem cell hypothesis does not contradict earlier concepts of carcinogenesis. The cancer stem cell hypothesis has been a proposed mechanism that contributes to tumour heterogeneity. While genetic and epigenetic alterations in tumor suppressor genes and oncogenes change the behavior of cells, th... | https://en.wikipedia.org/wiki?curid=2332422 |
Indicator diagram An indicator diagram is a chart used to estimate the performance of a steam engine. Specifically, an indicator chart records the pressure of steam versus the volume of steam in a cylinder, throughout a piston's cycle of motion in a steam engine. The indicator diagram enables calculation of the work pe... | https://en.wikipedia.org/wiki?curid=2332569 |
Indicator diagram Though it was made public in a letter to the "Quarterly Journal of Science" in 1822, it remained somewhat obscure, John Farey, Jr. only learning of it on seeing it used, probably by Watt's men, when he visited Russia in 1826. In 1834, Émile Clapeyron used a diagram of pressure against volume to illust... | https://en.wikipedia.org/wiki?curid=2332569 |
Edmond Frémy (; 28 February 1814 – 3 February 1894) was a French chemist. He is perhaps best known today for Frémy's salt, a strong oxidizing agent which he discovered in 1845. Fremy's salt is a long-lived free radical that finds use as a standard in electron paramagnetic resonance spectroscopy. Frémy was born at Versa... | https://en.wikipedia.org/wiki?curid=2333317 |
Edmond Frémy In this field he contributed to our knowledge of the manufacture of iron and steel, sulfuric acid, glass, and paper, and in particular worked at the saponification of fats with sulfuric acid and the utilization of palmitic acid for candle-making. In the later years of his life he applied himself to the pro... | https://en.wikipedia.org/wiki?curid=2333317 |
Beilstein database The is the largest database in the field of organic chemistry, in which compounds are uniquely identified by their Beilstein Registry Number. The database covers the scientific literature from 1771 to the present and contains experimentally validated information on millions of chemical reactions and ... | https://en.wikipedia.org/wiki?curid=2335158 |
Beilstein Journal of Organic Chemistry The is a peer-reviewed open-access scientific journal established in 2005. It is published by BioMed Central on behalf of the Beilstein Institute for the Advancement of Chemical Sciences, a German non-profit foundation. The editor-in-chief is Peter Seeberger (Max Planck Institute ... | https://en.wikipedia.org/wiki?curid=2335283 |
Best available technology The best available technology or best available techniques (BAT) is the technology approved by legislators or regulators for meeting output standards for a particular process, such as pollution abatement or pasteurization. Similar terms are "best practicable means" or "best practicable environ... | https://en.wikipedia.org/wiki?curid=2339273 |
Best available technology The "BAT" concept was first time used in the 1992 OSPAR Convention for the protection of the marine environment of the North-East Atlantic for all types of industrial installations (for instance, chemical plants). Some doctrine deem it already acquired the status of customary law. In the Unite... | https://en.wikipedia.org/wiki?curid=2339273 |
Best available technology BREFs are the result of an exchange of information between European Union Member States, the industries concerned, non-governmental organisations promoting environmental protection and the European Commission pursuant to article 13 of the directive. This exchange of information is often called... | https://en.wikipedia.org/wiki?curid=2339273 |
Best available technology The directive includes a definition of best available techniques in article 3(10): "best available techniques" means the most effective and advanced stage in the development of activities and their methods of operation which indicates the practical suitability of particular techniques for prov... | https://en.wikipedia.org/wiki?curid=2339273 |
Best available technology Environmental Protection Agency (EPA) identifies a particular model technology for an industry, and then writes a regulatory performance standard based on the model. The performance standard is typically expressed as a numeric effluent limit measured at the discharge point. The industrial faci... | https://en.wikipedia.org/wiki?curid=2339273 |
Barometric light is a name for the light that is emitted by a mercury-filled barometer tube when the tube is shaken. The discovery of this phenomenon in 1675 revealed the possibility of electric lighting. The earliest barometers were simply glass tubes that were closed at one end and filled with mercury. The tube was t... | https://en.wikipedia.org/wiki?curid=2341503 |
Barometric light was first observed in 1675 by the French astronomer Jean Picard: "Towards the year 1676, Monsieur Picard was transporting his barometer from the Observatory to Port Saint Michel during the night, [when] he noticed a light in a part of the tube where the mercury was moving; this phenomenon having surpri... | https://en.wikipedia.org/wiki?curid=2341503 |
Dendrite (metal) A dendrite in metallurgy is a characteristic tree-like structure of crystals growing as molten metal solidifies, the shape produced by faster growth along energetically favourable crystallographic directions. This dendritic growth has large consequences in regard to material properties. Dendrites form ... | https://en.wikipedia.org/wiki?curid=2343250 |
Dendrite (metal) The microstructural length scale is determined by the interplay or balance between the surface energy and the temperature gradient (which drives the heat/solute diffusion) in the liquid at the interface. As solidification proceeds, an increasing number of atoms lose their kinetic energy, making the pro... | https://en.wikipedia.org/wiki?curid=2343250 |
Dendrite (metal) The dendrites are also common in cast products, where they may become visible by etching of a polished specimen. As dendrites develop further into the liquid metal, they get hotter because they continue to extract heat. If they get too hot, they will remelt. This remelting of the dendrites is called re... | https://en.wikipedia.org/wiki?curid=2343250 |
Erythrolitmin (also called erythrolein) is the active ingredient extracted from the Litmus lichen, used in chemistry as a pH indicator. The erythrolitmin molecule is related to the orceins, and consists essentially of several phenoxazone and orcinol residues. The intense coloring of the molecule is generated by the abs... | https://en.wikipedia.org/wiki?curid=2343635 |
Temperature measurement Temperature measurement, also known as thermometry, describes the process of measuring a current local temperature for immediate or later evaluation. Datasets consisting of repeated standardized measurements can be used to assess temperature trends. Attempts at standardized temperature measureme... | https://en.wikipedia.org/wiki?curid=2343811 |
Temperature measurement Temperature increase causes the fluid to expand, so the temperature can be determined by measuring the volume of the fluid. Such thermometers are usually calibrated so that one can read the temperature simply by observing the level of the fluid in the thermometer. Another type of thermometer tha... | https://en.wikipedia.org/wiki?curid=2343811 |
Temperature measurement Airflow increases the rate of heat transfer from or to the body, resulting in a larger change in body temperature for the same ambient temperature. The theoretical basis for thermometers is the zeroth law of thermodynamics which postulates that if you have three bodies, A, B and C, if A and B ar... | https://en.wikipedia.org/wiki?curid=2343811 |
Temperature measurement The most promising and widespread non-invasive thermometric techniques in a biotech context are based on the analysis of magnetic resonance images, computerized tomography images and echotomography. These techniques allow monitoring temperature within tissues without introducing a sensing elemen... | https://en.wikipedia.org/wiki?curid=2343811 |
Temperature measurement ) or by the mean of the daily minimum and maximum readings (though the latter can result in mean temperatures up to 1 °C cooler or warmer than the true mean, depending on the time of observation). The world's average surface air temperature is about 14 °C. The American Society of Mechanical Engi... | https://en.wikipedia.org/wiki?curid=2343811 |
Dmitrii Knorre Dmitrii G. Knorre (Russian: Дмитрий Георгиевич Кнорре; born July 28, 1926 in Leningrad, Soviet Union; died 2018) is a chemist and biochemist, a specialist in chemical kinetics of complex reactions, bioorganic chemistry, and molecular biology. He was a Corresponding member of the Academy of Sciences of th... | https://en.wikipedia.org/wiki?curid=2345913 |
Dmitrii Knorre He is an honored scientist of the former Soviet Union. He is a laureate of the Prize of the Soviet Council of Ministers in 1987, and the M. M. Shemiakin Prize of the Academy of Sciences of the USSR in 1988. | https://en.wikipedia.org/wiki?curid=2345913 |
Vernis Martin In French interior design, vernis Martin is a type (or a number of types) of japanning or imitation lacquer named after the 18th century French Martin brothers: Guillaume (died 1749), Etienne-Simon, Robert and Julien. They ran a leading factory from between about 1730 and 1770, and were "vernisseurs du ro... | https://en.wikipedia.org/wiki?curid=2348372 |
Vernis Martin At the height of their fame the brothers directed at least three factories in Paris, and in 1748 they were all classed together as a "Manufacture nationale." One of them was still in existence in 1785. The literature of their day had much to say of the Martin brothers. In Voltaire's comedy "Nadine", produ... | https://en.wikipedia.org/wiki?curid=2348372 |
Vernis Martin This delicate work, "poudré" and wavy-lined with gold or semi with flowers overlaid with transparent enamel, is seen at its best on small boxes, fans, needle-cases and such-like. Of the larger specimens from the Martins' factories many have disappeared, or been cut up into decorative panels. It would appe... | https://en.wikipedia.org/wiki?curid=2348372 |
Barkhausen effect The is a name given to the noise in the magnetic output of a ferromagnet when the magnetizing force applied to it is changed. Discovered by German physicist Heinrich Barkhausen in 1919, it is caused by rapid changes of size of magnetic domains (similarly magnetically oriented atoms in ferromagnetic ma... | https://en.wikipedia.org/wiki?curid=2349703 |
Barkhausen effect The sudden transitions in the magnetization of the material produce current pulses in the coil, which when amplified produce a sound in the loudspeaker. This makes a crackling sound, which has been compared to candy being unwrapped, Rice Krispies, or the sound of a log fire. This sound, first discover... | https://en.wikipedia.org/wiki?curid=2349703 |
Barkhausen effect Therefore, the Barkhausen noise can be used as a method of non-destructive evaluation of the degradation of mechanical properties in magnetic materials subjected to cyclic mechanical stresses (e.g. in pipeline transport) or high-energy particles (e.g. nuclear reactor) or materials such as high-strengt... | https://en.wikipedia.org/wiki?curid=2349703 |
Tetrakis(triphenylphosphine)palladium(0) (sometimes called quatrotriphenylphosphine) is the chemical compound [Pd(P(CH))], often abbreviated Pd(PPh), or rarely PdP. It is a bright yellow crystalline solid that becomes brown upon decomposition in air. The four phosphorus atoms are at the corners of a tetrahedron surroun... | https://en.wikipedia.org/wiki?curid=2349872 |
Cyclooctatetraene 1,3,5,7-(COT) is an unsaturated derivative of cyclooctane, with the formula CH. It is also known as [8]annulene. This polyunsaturated hydrocarbon is a colorless to light yellow flammable liquid at room temperature. Because of its stoichiometric relationship to benzene, COT has been the subject of much... | https://en.wikipedia.org/wiki?curid=2349940 |
Cyclooctatetraene During World War 2, Walter Reppe at BASF Ludwigshafen developed a simple, one-step synthesis of cyclooctatetraene from acetylene, providing material identical to that prepared by Willstätter. Any remaining doubts on the accuracy of Willstätter's original synthesis were resolved when Arthur C. Cope and... | https://en.wikipedia.org/wiki?curid=2349940 |
Cyclooctatetraene Richard Willstätter's original synthesis (4 consecutive elimination reactions on a cyclooctane framework) gives relatively low yields. Reppe's synthesis of cyclooctatetraene, which involves treating acetylene at high pressure with a warm mixture of nickel cyanide and calcium carbide, was much better, ... | https://en.wikipedia.org/wiki?curid=2349940 |
Cyclooctatetraene Furthermore, polyacetylene can be synthesized via the ring-opening polymerization of cyclooctatetraene. COT itself—and also analogs with side-chains—have been used as metal ligands and in sandwich compounds. also undergoes rearrangement reactions to form aromatic ring systems. For instance, oxidation ... | https://en.wikipedia.org/wiki?curid=2349940 |
Thermal runaway occurs in situations where an increase in temperature changes the conditions in a way that causes a further increase in temperature, often leading to a destructive result. It is a kind of uncontrolled positive feedback. In other words, "thermal runaway" describes a process which is accelerated by increa... | https://en.wikipedia.org/wiki?curid=2350918 |
Thermal runaway is also called thermal explosion in chemical engineering, or runaway reaction in organic chemistry. It is a process by which an exothermic reaction goes out of control: the reaction rate increases due to an increase in temperature, causing a further increase in temperature and hence a further rapid incr... | https://en.wikipedia.org/wiki?curid=2350918 |
Thermal runaway This scenario was behind the Seveso disaster, where thermal runaway heated a reaction to temperatures such that in addition to the intended 2,4,5-trichlorophenol, poisonous 2,3,7,8-tetrachlorodibenzo-p-dioxin was also produced, and was vented into the environment after the reactor's rupture disk burst. ... | https://en.wikipedia.org/wiki?curid=2350918 |
Thermal runaway In 2007, this kind of erroneous procedure caused an explosion of a -reactor used to metalate methylcyclopentadiene with metallic sodium, causing the loss of four lives and parts of the reactor being flung away. Thus, industrial scale reactions prone to thermal runaway are preferably controlled by the ad... | https://en.wikipedia.org/wiki?curid=2350918 |
Thermal runaway This behavior, when the material gets exposed to microwaves, leads to selective local overheating, as the warmer areas are better able to accept further energy than the colder areas—potentially dangerous especially for thermal insulators, where the heat exchange between the hot spots and the rest of the... | https://en.wikipedia.org/wiki?curid=2350918 |
Thermal runaway The electrical load ends up funneling into a single device, which then rapidly fails. Thus, an array of devices may end up no more robust than its weakest component. The current-hogging effect can be reduced by carefully matching the characteristics of each paralleled device, or by using other design te... | https://en.wikipedia.org/wiki?curid=2350918 |
Thermal runaway This can lead to thermal runaway phenomena within internal regions of the semiconductor junction; the resistance decreases in the regions which become heated above this threshold, allowing more current to flow through the overheated regions, in turn causing yet more heating in comparison with the surrou... | https://en.wikipedia.org/wiki?curid=2350918 |
Thermal runaway One rule of thumb to avoid thermal runaway is to keep the operating point of a BJT so that V ≤ 1/2V Another practice is to mount a thermal feedback sensing transistor or other device on the heat sink, to control the crossover bias voltage. As the output transistors heat up, so does the thermal feedback ... | https://en.wikipedia.org/wiki?curid=2350918 |
Thermal runaway However, the increase of on-resistance with temperature helps balance current across multiple MOSFETs connected in parallel, so current hogging does not occur. If a MOSFET transistor produces more heat than the heatsink can dissipate, then thermal runaway can still destroy the transistors. This problem ... | https://en.wikipedia.org/wiki?curid=2350918 |
Thermal runaway The tantalum sponge then comes into direct contact with the manganese dioxide, and increased leakage current causes localized heating; usually, this drives an endothermic chemical reaction that produces manganese(III) oxide and regenerates (self-heals) the tantalum oxide dielectric layer. However, if th... | https://en.wikipedia.org/wiki?curid=2350918 |
Thermal runaway 34 K/W, although the actual thermal resistance to the environment is somewhat higher, due to the thermal boundary between processor and heatsink, rising temperatures in the case, and other thermal resistances.) Regardless, an inadequate heat sink with a thermal resistance of over 0.5 to 1 K/W would resu... | https://en.wikipedia.org/wiki?curid=2350918 |
Thermal runaway One of the possible solutions is in using safer and less reactive anode (lithium titanates) and cathode (lithium iron phosphate) materials — thereby avoiding the cobalt electrodes in many lithium rechargeable cells — together with non-flammable electrolytes based on ionic liquids. Runaway thermonuclear ... | https://en.wikipedia.org/wiki?curid=2350918 |
Thermal runaway 45 solar masses, helium fusion is ignited and takes off in a runaway fashion, called the helium flash, briefly increasing the star's energy production to a rate 100 billion times normal. About 6% of the core is quickly converted into carbon. While the release is sufficient to convert the core back into ... | https://en.wikipedia.org/wiki?curid=2350918 |
Thermal runaway As with novae, such bursts tend to repeat and may also be triggered by helium or even carbon fusion. It has been proposed that in the case of "superbursts", runaway breakup of accumulated heavy nuclei into iron group nuclei via photodissociation rather than nuclear fusion could contribute the majority o... | https://en.wikipedia.org/wiki?curid=2350918 |
Thermal runaway As the core heats further, the gamma rays eventually begin to pass the energy threshold needed for collision-induced decay into electron-positron pairs, a process called pair production. This causes a drop in the pressure within the core, leading it to contract and heat further, causing more pair produc... | https://en.wikipedia.org/wiki?curid=2350918 |
Glucuronidation is often involved in drug metabolism of substances such as drugs, pollutants, bilirubin, androgens, estrogens, mineralocorticoids, glucocorticoids, fatty acid derivatives, retinoids, and bile acids. These linkages involve glycosidic bonds. consists of transfer of the glucuronic acid component of uridine... | https://en.wikipedia.org/wiki?curid=2350960 |
Glucuronidation The conjugation of xenobiotic molecules with hydrophilic molecular species such as glucuronic acid is known as phase II metabolism. occurs mainly in the liver, although the enzyme responsible for its catalysis, UDP-glucuronyltransferase, has been found in all major body organs (e.g., intestine, kidneys,... | https://en.wikipedia.org/wiki?curid=2350960 |
Solar cell A solar cell, or photovoltaic cell, is an electrical device that converts the energy of light directly into electricity by the photovoltaic effect, which is a physical and chemical phenomenon. It is a form of photoelectric cell, defined as a device whose electrical characteristics, such as current, voltage, ... | https://en.wikipedia.org/wiki?curid=2352910 |
Solar cell Assemblies of solar cells are used to make solar modules that generate electrical power from sunlight, as distinguished from a "solar thermal module" or "solar hot water panel". A solar array generates solar power using solar energy. Multiple solar cells in an integrated group, all oriented in one plane, con... | https://en.wikipedia.org/wiki?curid=2352910 |
Solar cell In 1839, at age 19, he built the world's first photovoltaic cell in his father's laboratory. Willoughby Smith first described the "Effect of Light on Selenium during the passage of an Electric Current" in a 20 February 1873 issue of Nature. In 1883 Charles Fritts built the first solid state photovoltaic cell... | https://en.wikipedia.org/wiki?curid=2352910 |
Solar cell The space power market drove the development of higher efficiencies in solar cells up until the National Science Foundation "Research Applied to National Needs" program began to push development of solar cells for terrestrial applications. In the early 1990s the technology used for space solar cells diverged... | https://en.wikipedia.org/wiki?curid=2352910 |
Solar cell These small panels would be unfolded into a large panel after the satellite is deployed in its orbit. Newer satellites aim to use flexible rollable solar arrays that are very lightweight and can be packed into a very small volume. The smaller size and weight of these flexible arrays drastically decreases the... | https://en.wikipedia.org/wiki?curid=2352910 |
Solar cell The team eliminated the steps of polishing the wafers and coating them with an anti-reflective layer, relying on the rough-sawn wafer surface. The team also replaced the expensive materials and hand wiring used in space applications with a printed circuit board on the back, acrylic plastic on the front, and ... | https://en.wikipedia.org/wiki?curid=2352910 |
Subsets and Splits
No community queries yet
The top public SQL queries from the community will appear here once available.