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Inhibitor
Inhibitor or inhibition may refer to: In biology * Enzyme inhibitor, a substance that binds to an enzyme and decreases the enzyme's activity * Reuptake inhibitor, a substance that increases neurotransmission by blocking the reuptake of a neurotransmitter * Lateral inhibition, a neural mechanism that increases contrast between active and (neighbouring) inactive neurons * Inhibitory postsynaptic potential, a synaptic potential that decreases the firing of a neuron In chemistry * Corrosion inhibitor, a substance that decreases the rate of metal oxidation * Reaction inhibitor, a substance that prevents or decreases the rate of a chemical reaction * Polymerisation inhibitor, a substance that inhibits unwanted polymerisation of monomers In psychology * Cognitive inhibition, the mind's ability to tune out irrelevant stimuli ** Inhibitory control, a cognitive process that permits an individual to inhibit their impulses * Inhibition of return, a feature of attention * Inhibition theor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Enzyme Inhibitor
An enzyme inhibitor is a molecule that binds to an enzyme and blocks its activity. Enzymes are proteins that speed up chemical reactions necessary for life, in which substrate molecules are converted into products. An enzyme facilitates a specific chemical reaction by binding the substrate to its active site, a specialized area on the enzyme that accelerates the most difficult step of the reaction. An enzyme inhibitor stops ("inhibits") this process, either by binding to the enzyme's active site (thus preventing the substrate itself from binding) or by binding to another site on the enzyme such that the enzyme's catalysis of the reaction is blocked. Enzyme inhibitors may bind reversibly or irreversibly. Irreversible inhibitors form a chemical bond with the enzyme such that the enzyme is inhibited until the chemical bond is broken. By contrast, reversible inhibitors bind non-covalently and may spontaneously leave the enzyme, allowing the enzyme to resume its function. Reve ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Revelation Space Universe
The ''Revelation Space'' series is a book series created by Alastair Reynolds that debuted with the novel '' Revelation Space'' in 2000. The fictional universe it is set in is used as the setting for a number of his novels and stories. Its fictional history follows the human species through various conflicts from the relatively near future (roughly 2200) to approximately 40,000 AD (all the novels to date are set between 2427 and 2727, although certain stories extend beyond this period). It takes its name from '' Revelation Space'' (2000), which was the first published novel set in the universe. Universe The ''Revelation Space'' universe is a fictional universe which was set in a future version of our world, with the addition of a number of extraterrestrial species and advanced technologies that are not necessarily grounded in current science. It is, nonetheless, somewhat "harder" than most examples of space opera, relying to a considerable extent on science Reynolds believes ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Inhibitory Postsynaptic Potential
An inhibitory postsynaptic potential (IPSP) is a kind of synaptic potential that makes a postsynaptic neuron less likely to generate an action potential.Purves et al. Neuroscience. 4th ed. Sunderland (MA): Sinauer Associates, Incorporated; 2008. IPSP were first investigated in motorneurons by David P. C. Lloyd, John Eccles and Rodolfo Llinás in the 1950s and 1960s. The opposite of an inhibitory postsynaptic potential is an excitatory postsynaptic potential (EPSP), which is a synaptic potential that makes a postsynaptic neuron ''more'' likely to generate an action potential. IPSPs can take place at all chemical synapses, which use the secretion of neurotransmitters to create cell to cell signalling. Inhibitory presynaptic neurons release neurotransmitters that then bind to the postsynaptic receptors; this induces a change in the permeability of the postsynaptic neuronal membrane to particular ions. An electric current that changes the postsynaptic membrane potential to create ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Inhibitory Control
Inhibitory control, also known as response inhibition, is a cognitive process – and, more specifically, an executive function – that permits an individual to inhibit their impulses and natural, habitual, or dominant behavioral responses to stimuli ( prepotent responses) in order to select a more appropriate behavior that is consistent with completing their goals. Self-control is an important aspect of inhibitory control. For example, successfully suppressing the natural behavioral response to eat cake when one is craving it while dieting requires the use of inhibitory control. The prefrontal cortex, caudate nucleus, and subthalamic nucleus are known to regulate inhibitory control cognition. Inhibitory control is impaired in both addiction and attention deficit hyperactivity disorder. In healthy adults and ADHD individuals, inhibitory control improves over the short term with low (therapeutic) doses of methylphenidate or amphetamine. Inhibitory control may also be ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reaction Inhibitor
A reaction inhibitor is a substance that decreases the rate of, or prevents, a chemical reaction. A catalyst, in contrast, is a substance that increases the rate of a chemical reaction. Examples * Added acetanilide slows the decomposition of drug-store hydrogen peroxide solution, inhibiting the reaction 2 → 2 + , which is catalyzed by heat, light, and impurities.The decomposition of hydrogen peroxide Inhibition of a catalyst An inhibitor can reduce the effectiveness of a catalyst in a catalysed reaction (either a non-biological catalyst or an enzyme). E.g., if a compound is so similar to (one of) the reactants that it can bind to the active site of a catalyst but does not undergo a catalytic reaction then that catalyst molecule cannot perform its job because the active site is occupied. When the inhibitor is released, the catalyst is again available for reaction. Inhibition and catalyst poisoning Inhibition should be distinguished from catalyst poisoning. An inhibitor only hin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polymerisation Inhibitor
Polymerisation inhibitors (US: polymerization inhibitors) are chemical compounds added to monomers to prevent their auto-polymerisation. Unsaturated monomers such as acrylates, vinyl chloride, butadiene and styrene require inhibitors for both processing and safe transport and storage. Many monomers are purified industrially by distillation, which can lead to thermally initiated polymerisation. Styrene for example is distilled at temperatures above 100 °C whereupon it undergoes thermal polymerisation at a rate of ~2% per hour. This polymerisation is undesirable, as it can foul the fractionating tower, it is also typically exothermic which can lead to a runaway reaction and potential explosion if left unchecked. Once initiated polymerisation is typically radical in mechanism and as such many polymerisation inhibitors act as radical scavengers. Inhibitors vs retarders The term 'inhibitor' is often used in a general sense to describe any compound used to prevent unwanted polymeri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Corrosion Inhibitor
In chemistry, a corrosion inhibitor or anti-corrosive is a chemical compound that, when added to a liquid or gas, decreases the corrosion rate of a material, typically a metal or an alloy, that comes into contact with the fluid. The effectiveness of a corrosion inhibitor depends on fluid composition, quantity of water, and flow regime. Corrosion inhibitors are common in industry, and also found in over-the-counter products, typically in spray form in combination with a lubricant and sometimes a penetrating oil. They may be added to water to prevent leaching of lead or copper from pipes. A common mechanism for inhibiting corrosion involves formation of a coating, often a passivation layer, which prevents access of the corrosive substance to the metal. Permanent treatments such as chrome plating are not generally considered inhibitors, however: corrosion inhibitors are additives to the fluids that surround the metal or related object. Types The nature of the corrosive inhibitor de ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cognitive Inhibition
Cognitive inhibition refers to the mind's ability to tune out stimuli that are irrelevant to the task/process at hand or to the mind's current state. Cognitive inhibition can be done either in whole or in part, intentionally or otherwise. Cognitive inhibition in particular can be observed in many instances throughout specific areas of cognitive science. History The early models of what would become the study and concept of cognitive inhibition were developed by Sigmund Freud. Inhibition was believed to play two primary roles: the prevention of unwanted thoughts or behaviors, and the repression of experiences from infancy and childhood. Freud believed cognitive inhibition was not just a lack of awareness to stimuli but an active process, requiring a constant energy expenditure. Other early theories of cognitive inhibition focused on its central developmental mechanisms and were founded by Luria and Vygotsky, two Russian psychologists. They proposed that children acquire control o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Inhibition Of Return
Inhibition of return (IOR) refers to an orientation mechanism that briefly enhances (for approximately 100–300 milliseconds (ms)) the speed and accuracy with which an object is detected after the object is attended, but then impairs detection speed and accuracy (for approximately 500–3000 milliseconds). IOR is usually measured with a cue-response paradigm, in which a person presses a button when they detect a target Stimulus (psychology), stimulus following the presentation of a cue that indicates the location in which the target will appear. The cue can be exogenous (or peripheral), or endogenous. Inhibition of return results from oculomotor activation, regardless of whether it was produced by exogenous signals or endogenously. Although IOR occurs for both visual and auditory stimuli, IOR is greater for visual stimuli, and is studied more often than auditory stimuli. Description IOR was first described in depth by Michael Posner (psychologist), Michael Posner and Yoav Cohen, w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Food Preservation
Food preservation includes processes that make food more resistant to microorganism growth and slow the oxidation of fats. This slows down the decomposition and rancidification process. Food preservation may also include processes that inhibit visual deterioration, such as the enzymatic browning reaction in apples after they are cut during food preparation. By preserving food, food waste can be reduced, which is an important way to decrease production costs and increase the efficiency of food systems, improve food security and nutrition and contribute towards environmental sustainability. For instance, it can reduce the environmental impact of food production. Many processes designed to preserve food involve more than one food preservation method. Preserving fruit by turning it into jam, for example, involves boiling (to reduce the fruit's moisture content and to kill bacteria, etc.), sugaring (to prevent their re-growth) and sealing within an airtight jar (to prevent reconta ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Embalming
Embalming is the art and science of preserving human remains by treating them (in its modern form with chemicals) to forestall decomposition. This is usually done to make the deceased suitable for public or private viewing as part of the funeral ceremony or keep them preserved for medical purposes in an anatomical laboratory. The three goals of embalming are sanitization, presentation, and preservation, with restoration being an important additional factor in some instances. Performed successfully, embalming can help preserve the body for a duration of many years. Embalming has a very long and cross-cultural history, with many cultures giving the embalming processes a greater religious meaning. Animal remains can also be embalmed by similar methods, but embalming is distinct from taxidermy. Embalming preserves the body intact, whereas taxidermy is the recreation of an animal's form often using only the creature's skin mounted on an anatomical form. History It is important to n ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Preservative
A preservative is a substance or a chemical that is added to products such as food products, beverages, pharmaceutical drugs, paints, biological samples, cosmetics, wood, and many other products to prevent decomposition by microbial growth or by undesirable chemical changes. In general, preservation is implemented in two modes, chemical and physical. Chemical preservation entails adding chemical compounds to the product. Physical preservation entails processes such as refrigeration or drying.Erich Lück and Gert-Wolfhard von Rymon Lipinski "Foods, 3. Food Additives" in ''Ullmann's Encyclopedia of Industrial Chemistry'', 2002, Wiley-VCH, Weinheim. Preservative food additives reduce the risk of foodborne infections, decrease microbial spoilage, and preserve fresh attributes and nutritional quality. Some physical techniques for food preservation include dehydration, UV-C radiation, freeze-drying, and refrigeration. Chemical preservation and physical preservation techniques are som ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
