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In quantum mechanics , and especially quantum information theory, the purity of a normalized quantum state is a scalar defined as γ ≡ tr ( ρ 2 ) {\displaystyle \gamma \,\equiv \,\operatorname {tr} (\rho ^{2})} where ρ {\displaystyle \rho \,} is the density matrix of the state and tr {\displaystyle \operatorname {tr} ... | https://en.wikipedia.org/wiki/Purity_(quantum_mechanics) |
A purlin (or historically purline , purloyne , purling , perling ) is a longitudinal, horizontal, structural member in a roof . In traditional timber framing there are three basic types of purlin: purlin plate, principal purlin, and common purlin.
Purlins also appear in steel frame construction. Steel purlins may be ... | https://en.wikipedia.org/wiki/Purlin |
The Purnell equation is an equation used in analytical chemistry to calculate the resolution R s between two peaks in a chromatogram . [ 1 ] [ 2 ]
where
The higher the resolution, the better the separation.
This article about analytical chemistry is a stub . You can help Wikipedia by expanding it .
This article rel... | https://en.wikipedia.org/wiki/Purnell_equation |
The Purple Earth Hypothesis (PEH) is an astrobiological hypothesis , first proposed by molecular biologist Shiladitya DasSarma in 2007, [ 1 ] that the earliest photosynthetic life forms of Early Earth were based on the simpler molecule retinal rather than the more complex porphyrin -based chlorophyll , making the surfa... | https://en.wikipedia.org/wiki/Purple_Earth_hypothesis |
Purple Ocean was a bulletin board system (BBS) founded in June 1984 by system operator (SysOp) Dustin Malcom in Plano, Texas . These early BBS systems were typically run by individual users or small groups and were often hosted on personal computers in users’ homes or garages. They provided a space for users to share i... | https://en.wikipedia.org/wiki/Purple_Ocean |
VMware ESXi (formerly ESX ) is an enterprise-class , type-1 hypervisor developed by VMware , a subsidiary of Broadcom , for deploying and serving virtual computers . As a type-1 hypervisor, ESXi is not a software application that is installed on an operating system (OS); instead, it includes and integrates vital OS com... | https://en.wikipedia.org/wiki/Purple_Screen_of_Death |
Purple of Cassius is a purple pigment formed by the reaction of gold salts with tin(II) chloride . It has been used to impart glass with a red coloration (see cranberry glass ), as well as to determine the presence of gold as a chemical test .
Generally, the preparation of this material involves gold being dissolved i... | https://en.wikipedia.org/wiki/Purple_of_Cassius |
Paecillium Luangsa-ard, Hywel-Jones & Samson nom. prov. (2007) [ 1 ] Penicillium lilacinum Thom (1910) Penicillium amethystinum Wehmer (1923) Spicaria rubidopurpurea Aoki (1941) Paecilomyces lilacinus ( Thom ) Samson (1974)
Purpureocillium lilacinum is a species of filamentous fungus in the family Ophiocordycipitaceae... | https://en.wikipedia.org/wiki/Purpureocillium_lilacinum |
Pursuit predation is a form of predation in which predators actively give chase to their prey , either solitarily or as a group . It is an alternate predation strategy to ambush predation — pursuit predators rely on superior speed , endurance and/or teamwork to seize the prey, while ambush predators use concealment , ... | https://en.wikipedia.org/wiki/Pursuit_predation |
A push-button (also spelled pushbutton ) or simply button is a simple switch mechanism to control some aspect of a machine or a process . Buttons are typically made out of hard material, usually plastic or metal . [ 1 ] The surface is usually flat or shaped to accommodate the human finger or hand, so as to be easily de... | https://en.wikipedia.org/wiki/Push-button |
A Push Proxy Gateway is a component of WAP Gateways that pushes URL notifications to mobile handsets. Notifications typically include MMS , email, IM, ringtone downloads, and new device firmware notifications. Most notifications will have an audible alert to the user of the device. The notification will typically be a... | https://en.wikipedia.org/wiki/Push_Proxy_Gateway |
The push of the past [ 1 ] [ 2 ] is a type of survivorship bias associated with evolutionary diversification when extinction is possible. Groups that survive a long time are likely to have “got off to a flying start”, [ 1 ] and this statistical bias creates an illusion of a true slow-down of diversification rate throug... | https://en.wikipedia.org/wiki/Push_of_the_past |
pushd and popd are shell commands that together allow the user to revert to a previous working directory via the command line. They use a stack data structure for directory paths. pushd pushes the working directory path onto the stack and changes to the specified directory, and popd pops the most recent item from the s... | https://en.wikipedia.org/wiki/Pushd_and_popd |
A pusher centrifuge is a type of filtration device that offers continuous operation to de-water and wash materials such as relatively incompressible feed solids, free-draining crystalline materials, polymers and fibrous substances. It consists of a constant speed rotor and is fixed to one of several baskets. This assem... | https://en.wikipedia.org/wiki/Pusher_centrifuge |
In algebraic topology , the pushforward of a continuous function f {\displaystyle f} : X → Y {\displaystyle X\rightarrow Y} between two topological spaces is a homomorphism f ∗ : H n ( X ) → H n ( Y ) {\displaystyle f_{*}:H_{n}\left(X\right)\rightarrow H_{n}\left(Y\right)} between the homology groups for n ≥ 0 {\displa... | https://en.wikipedia.org/wiki/Pushforward_(homology) |
Push–pull technology is an intercropping strategy for controlling agricultural pests by using repellent "push" plants and trap "pull" plants . [ 1 ] For example, cereal crops like maize or sorghum are often infested by stem borers . Grasses planted around the perimeter of the crop attract and trap the pests, whereas ot... | https://en.wikipedia.org/wiki/Push–pull_agricultural_pest_management |
A push-pull olefin is a type of olefin characterized by an electron-withdrawing substituent on one side of the double bond and an electron-donating substituent on the other side. This makes the pi bond very polarized . The rotational barrier for a push-pull olefin is lower than that of an ordinary olefin and this makes... | https://en.wikipedia.org/wiki/Push–pull_olefin |
Push–pull perfusion is an in vivo sampling method most commonly used for measuring neurotransmitters in the brain. Developed by J.H. Gaddum in 1960, [ 1 ] this technique replaced the cortical cup technique for observing neurotransmitters.
In order to analyze concentrations of analytes such as neurotransmitters, a prob... | https://en.wikipedia.org/wiki/Push–pull_perfusion |
A putative gene is an alignment segment of DNA that is believed to be a gene . Putative genes can share sequence similarities to already characterized genes and thus can be inferred to share a similar function, yet the exact function of putative genes remains unknown. [ 1 ] Newly identified sequences are considered put... | https://en.wikipedia.org/wiki/Putative_gene |
Putrefaction is the fifth stage of death , following pallor mortis , livor mortis , algor mortis , and rigor mortis . This process references the breaking down of a body of an animal post-mortem . In broad terms, it can be viewed as the decomposition of proteins , and the eventual breakdown of the cohesiveness between ... | https://en.wikipedia.org/wiki/Putrefaction |
Putrefying/decay bacteria are bacteria involved in putrefaction of living matter. Along with other decomposers , they play a critical role in recycling nitrogen from dead organisms. [ 1 ] Putrefying bacteria also play a role in putrefaction and fermentation of proteins in the human gastrointestinal tract . [ 2 ]
Putre... | https://en.wikipedia.org/wiki/Putrefying_bacteria |
Pwo polymerase is a thermostable DNA polymerase used for the polymerase chain reaction . The abbreviation stands for Pyrococcus woesei , a thermophilic archaeon, from which this polymerase was isolated. This polymerase breaks when reaching erroneous uracil in DNA from the chain extension and, through this readahead fun... | https://en.wikipedia.org/wiki/Pwo_DNA_polymerase |
PyAOP ( (7-Azabenzotriazol-1-yloxy)tripyrrolidinophosphonium hexafluorophosphate ) is a reagent used to prepare amides from carboxylic acids and amines in the context of peptide synthesis . [ 1 ] It can be prepared from 1-hydroxy-7-azabenzotriazole (HOAt) and a chlorophosphonium reagent under basic conditions. [ 2 ] It... | https://en.wikipedia.org/wiki/PyAOP_reagent |
PyBOP (benzotriazol-1-yloxytripyrrolidinophosphonium hexafluorophosphate) is a reagent used to prepare amides from carboxylic acids and amines in the context of peptide synthesis . [ 3 ] It can be prepared from 1-hydroxybenzotriazole and a chlorophosphonium reagent under basic conditions. [ 4 ] It is a substitute for t... | https://en.wikipedia.org/wiki/PyBOP |
PyClone is a software that implements a Hierarchical Bayes statistical model to estimate cellular frequency patterns of mutations in a population of cancer cells using observed alternate allele frequencies , copy number , and loss of heterozygosity (LOH) information. PyClone outputs clusters of variants based on calcul... | https://en.wikipedia.org/wiki/PyClone |
PyMOL is a source-available [ 2 ] molecular visualization system created by Warren Lyford DeLano . It was commercialized initially by DeLano Scientific LLC, which was a private software company dedicated to creating useful tools that become universally accessible to scientific and educational communities. It is current... | https://en.wikipedia.org/wiki/PyMOL |
OpenMS is an open-source project for data analysis and processing in mass spectrometry and is released under the 3-clause BSD licence . It supports most common operating systems including Microsoft Windows , MacOS and Linux . [ 2 ] [ 3 ]
OpenMS has tools for analysis of proteomics data, providing algorithms for signal... | https://en.wikipedia.org/wiki/PyOpenMS |
Python-based Simulations of Chemistry Framework ( PySCF ) is an ab initio computational chemistry program natively implemented in Python program language. [ 1 ] [ 2 ] The package aims to provide a simple, light-weight and efficient platform for quantum chemistry code developing and calculation. It provides various fun... | https://en.wikipedia.org/wiki/PySCF |
A pycnidium (plural pycnidia ) is an asexual fruiting body produced by mitosporic fungi , for instance in the order Sphaeropsidales ( Deuteromycota , Coelomycetes ) or order Pleosporales ( Ascomycota , Dothideomycetes ). It is often spherical or inversely pearshaped ( obpyriform ) and its internal cavity is lined with ... | https://en.wikipedia.org/wiki/Pycnidium |
Pycniospores are a type of spore found in certain species of rust fungi . [ 1 ] [ 2 ] They are produced in special cup-like structures called pycnia or pynidia. Almost all fungi reproduce asexually with the production of spores. Spores may be colorless, green, yellow, orange, red, brown or black.
Sporangiospores (spo... | https://en.wikipedia.org/wiki/Pycniospore |
Pycnonuclear fusion (from Ancient Greek πυκνός (pyknós) ' dense, compact, thick ' ) is a type of nuclear fusion reaction which occurs due to zero-point oscillations of nuclei around their equilibrium point bound in their crystal lattice . [ 1 ] [ 2 ] In quantum physics , the phenomenon can be interpreted as overlap of ... | https://en.wikipedia.org/wiki/Pycnonuclear_fusion |
Pydlpoly is a molecular dynamics simulation package which is a modified version of DL-POLY with a Python language interface. Pydlpoly is written by Rochus Schmid in Ruhr University Bochum , Germany.
This article about molecular modelling software is a stub . You can help Wikipedia by expanding it . | https://en.wikipedia.org/wiki/Pydlpoly |
Pyknosis , or karyopyknosis , is the irreversible condensation of chromatin in the nucleus of a cell undergoing necrosis [ 1 ] or apoptosis . [ 2 ] It is followed by karyorrhexis , or fragmentation of the nucleus.
Pyknosis (from Ancient Greek πυκνός meaning "thick, closed or condensed") is also observed in the maturat... | https://en.wikipedia.org/wiki/Pyknosis |
In mathematics, especially in topology , a pyknotic set is a sheaf of sets on the site of compact Hausdorff spaces (with some fixed Grothendieck universes ). The notion was introduced by Barwick and Haine to provide a convenient setting for homological algebra . [ 1 ] The term pyknotic comes from the Greek πυκνός, mean... | https://en.wikipedia.org/wiki/Pyknotic_set |
Pyoluteorin is a natural antibiotic that is biosynthesized from a hybrid nonribosomal peptide synthetase (NRPS) and polyketide synthase (PKS) pathway. [ 1 ] Pyoluteorin was first isolated in the 1950s from Pseudomonas aeruginosa strains T359 and IFO 3455 [ 2 ] and was found to be toxic against oomycetes , bacteria , fu... | https://en.wikipedia.org/wiki/Pyoluteorin |
Pyramidal alkenes are alkenes in which the two carbon atoms making up the double bond are not coplanar with their four substituents . This deformation results from geometric constraints. Pyramidal alkenes only are of interest because much can be learned from them about the nature of chemical bonding . [ 1 ]
Twisting t... | https://en.wikipedia.org/wiki/Pyramidal_alkene |
In chemistry , pyramidal inversion (also umbrella inversion ) is a fluxional process in compounds with a pyramidal molecule, such as ammonia (NH 3 ) "turns inside out". [ 1 ] [ 2 ] It is a rapid oscillation of the atom and substituents, the molecule or ion passing through a planar transition state . [ 3 ] For a compoun... | https://en.wikipedia.org/wiki/Pyramidal_inversion |
A pyranometer (from Greek πῦρ (pyr) ' fire ' and ἄνω (ano) ' above, sky ' ) is a type of actinometer used for measuring solar irradiance on a planar surface and it is designed to measure the solar radiation flux density (W/m 2 ) from the hemisphere above within a wavelength range 0.3 μm to 3 μm.
A typical pyranometer ... | https://en.wikipedia.org/wiki/Pyranometer |
In organic chemistry , pyranose is a collective term for saccharides that have a chemical structure that includes a six-membered ring consisting of five carbon atoms and one oxygen atom (a heterocycle ). There may be other carbons external to the ring. The name derives from its similarity to the oxygen heterocycle pyra... | https://en.wikipedia.org/wiki/Pyranose |
Pyrenoids are sub-cellular phase-separated micro-compartments found in chloroplasts of many algae , [ 1 ] and in a single group of land plants, the hornworts . [ 2 ] [ 3 ] Pyrenoids are associated with the operation of a carbon-concentrating mechanism (CCM). Their main function is to act as centres of carbon dioxide (C... | https://en.wikipedia.org/wiki/Pyrenoid |
Pyrethrin I is one of the two pyrethrins , natural organic compounds with potent insecticidal activity. It is an ester of (+)- trans - chrysanthemic acid with ( S )-( Z )- pyrethrolone .
The synthesis of pyrethrin I involves the esterification of (+)- trans -chrysanthemic acid with (S)-(Z)-pyrethrolone. One synthetic ... | https://en.wikipedia.org/wiki/Pyrethrin_I |
A pyrheliometer is an instrument that can measure direct beam solar irradiance . [ 1 ] Sunlight enters the instrument through a window and is directed onto a thermopile which converts heat to an electrical signal that can be recorded. The signal voltage is converted via a formula to measure watts per square metre.
Pyr... | https://en.wikipedia.org/wiki/Pyrheliometer |
Pyric herbivory is the term for the interactions of fire with grazing on a grassland . [ 1 ] These interactions can promote biodiversity and function of grasslands. [ 1 ] Fire will increase the amount of grazing in a certain area, as grazing herbivores prefer the nutritious forage available in recently burned areas. [ ... | https://en.wikipedia.org/wiki/Pyric_herbivory |
Pyridine is a basic heterocyclic organic compound with the chemical formula C 5 H 5 N . It is structurally related to benzene , with one methine group (=CH−) replaced by a nitrogen atom (=N−) . It is a highly flammable, weakly alkaline , water-miscible liquid with a distinctive, unpleasant fish-like smell. Pyridine is... | https://en.wikipedia.org/wiki/Pyridine |
Pyridine- N -oxide is the heterocyclic compound with the formula C 5 H 5 NO. This colourless, hygroscopic solid is the product of the oxidation of pyridine . Its synthesis was first reported by Jakob Meisenheimer , who used peroxybenzoic acid as the oxidant. [ 1 ] The compound is used infrequently as an oxidizing reag... | https://en.wikipedia.org/wiki/Pyridine-N-oxide |
This page provides supplementary chemical data on pyridine .
The handling of this chemical may incur notable safety precautions. It is highly recommend that you seek the Material Safety Datasheet ( MSDS ) for this chemical from a reliable source such as eChemPortal , and follow its directions. MSDS is available from S... | https://en.wikipedia.org/wiki/Pyridine_(data_page) |
Pyridinium chlorochromate ( PCC ) is a yellow-orange salt with the formula [C 5 H 5 NH] + [CrO 3 Cl] − . It is a reagent in organic synthesis used primarily for oxidation of alcohols to form carbonyls . A variety of related compounds are known with similar reactivity. PCC offers the advantage of the selective oxidation... | https://en.wikipedia.org/wiki/Pyridinium_chlorochromate |
Pyridinium p -toluenesulfonate ( PPTS ) is a colourless solid salt of pyridine and p -toluenesulfonic acid .
In organic synthesis , PPTS is used as a weakly acidic catalyst , providing an organic soluble source of pyridinium (C 5 H 5 NH + ) ions. For example, PPTS is used to deprotect silyl ethers or tetrahydropyranyl... | https://en.wikipedia.org/wiki/Pyridinium_p-toluenesulfonate |
Pyridinium perbromide (also called pyridinium bromide perbromide , pyridine hydrobromide perbromide , or pyridinium tribromide ) is an organic chemical composed of a pyridinium cation and a tribromide anion. It can also be considered as a complex containing pyridinium bromide—the salt of pyridine and hydrogen bromide —... | https://en.wikipedia.org/wiki/Pyridinium_perbromide |
Pyrimidine ( C 4 H 4 N 2 ; / p ɪ ˈ r ɪ . m ɪ ˌ d iː n , p aɪ ˈ r ɪ . m ɪ ˌ d iː n / ) is an aromatic , heterocyclic , organic compound similar to pyridine ( C 5 H 5 N ). [ 3 ] One of the three diazines (six-membered heterocyclics with two nitrogen atoms in the ring), it has nitrogen atoms at positions 1 and 3 in the ri... | https://en.wikipedia.org/wiki/Pyrimidine |
Pyrimidine analogues are antimetabolites which mimic the structure of metabolic pyrimidines .
Pyrimidine antimetabolites are commonly used to treat cancer by interfering with DNA replication. [ 1 ]
This biochemistry article is a stub . You can help Wikipedia by expanding it . | https://en.wikipedia.org/wiki/Pyrimidine_analogue |
Pyrimidine biosynthesis occurs both in the body and through organic synthesis. [ 1 ]
De Novo biosynthesis of a pyrimidine is catalyzed by three gene products CAD, DHODH and UMPS. The first three enzymes of the process are all coded by the same gene in CAD which consists of carbamoyl phosphate synthetase II , aspartate... | https://en.wikipedia.org/wiki/Pyrimidine_biosynthesis |
Pyrimidine dimers represent molecular lesions originating from thymine or cytosine bases within DNA , resulting from photochemical reactions . [ 1 ] [ 2 ] These lesions, commonly linked to direct DNA damage , [ 3 ] are induced by ultraviolet light (UV), particularly UVC , result in the formation of covalent bonds betwe... | https://en.wikipedia.org/wiki/Pyrimidine_dimer |
Pyrimidine biosynthesis occurs both in the body and through organic synthesis. [ 1 ]
De Novo biosynthesis of a pyrimidine is catalyzed by three gene products CAD, DHODH and UMPS. The first three enzymes of the process are all coded by the same gene in CAD which consists of carbamoyl phosphate synthetase II , aspartate... | https://en.wikipedia.org/wiki/Pyrimidine_metabolism |
The mineral pyrite ( / ˈ p aɪ r aɪ t / PY -ryte ), [ 6 ] or iron pyrite , also known as fool's gold , is an iron sulfide with the chemical formula Fe S 2 (iron (II) disulfide). Pyrite is the most abundant sulfide mineral . [ 7 ]
Pyrite's metallic luster and pale brass-yellow hue give it a superficial resemblance to go... | https://en.wikipedia.org/wiki/Pyrite |
Pyrococcus yayanosii is a strictly anaerobic , hyperthermophilic archaeon , first identified through samples from the Mid-Atlantic Ridge . [ 1 ] Isolated from a deep-sea hydrothermal vent , it is characterized as a motile Gram-negative marine bacteria that is roughly cocci shaped and 1-1.5 μm in diameter, with lophotri... | https://en.wikipedia.org/wiki/Pyrococcus_yayanosii |
Pyroelectric fusion refers to the technique of using pyroelectric crystals to generate high strength electrostatic fields to accelerate deuterium ions ( tritium might also be used someday) into a metal hydride target also containing deuterium (or tritium) with sufficient kinetic energy to cause these ions to undergo nu... | https://en.wikipedia.org/wiki/Pyroelectric_fusion |
Pyroelectricity (from Greek: pyr (πυρ), "fire" and electricity ) is a property of certain crystals which are naturally electrically polarized and as a result contain large electric fields. [ 1 ] Pyroelectricity can be described as the ability of certain materials to generate a temporary voltage when they are heated or ... | https://en.wikipedia.org/wiki/Pyroelectricity |
Pyrogallol is an organic compound with the formula C 6 H 3 (OH) 3 . It is a water-soluble, white solid although samples are typically brownish because of its sensitivity toward oxygen. [ 3 ] It is one of three isomers of benzenetriols .
It is produced in the manner first reported by Scheele in 1786: heating gallic aci... | https://en.wikipedia.org/wiki/Pyrogallol |
A pyrogallolarene (also calix[4]pyrogallolarene ) is a macrocycle , or a cyclic oligomer , based on the condensation of pyrogallol (1,2,3-trihydroxybenzene) and an aldehyde . Pyrogallolarenes are a type of calixarene , and a subset of resorcinarenes that are substituted with a hydroxyl at the 2-position.
Pyrogallolare... | https://en.wikipedia.org/wiki/Pyrogallolarenes |
Pyroglutamyl-histidyl-glycine ( pEHG ) is an endogenous tripeptide that acts as a tissue-specific antimitotic and selectively inhibits the proliferation of colon epithelial cells. [ 1 ] Early research indicated that pEHG had anorectic effects in mice and was possibly involved in the pathophysiology of anorexia nervosa ... | https://en.wikipedia.org/wiki/Pyroglutamyl-histidyl-glycine |
A pyrolant (from Greek pyr , fire) is an energetic material that generates hot flames upon combustion . Pyrolants are metal-based pyrotechnic compositions containing virtually any oxidizer.
The term was originally coined by Kuwahara in 1992, [ 1 ] in a paper on magnesium/Teflon/Viton , to distinguish between compositio... | https://en.wikipedia.org/wiki/Pyrolant |
Pyrolysis is a process involving the separation of covalent bonds in organic matter by thermal decomposition within an inert environment without oxygen. [ 1 ] [ 2 ] [ 3 ]
The word pyrolysis is coined from the Greek -derived elements pyro- (from Ancient Greek πῦρ : pûr - "fire, heat, fever") and lysis ( λύσις : lúsis ... | https://en.wikipedia.org/wiki/Pyrolysis |
Pyrolysis gasoline or pygas is a naphtha -range product with high aromatics content. [ 1 ] It is a by-product of high temperature naphtha cracking during ethylene and propylene production, a high octane number mixture that contains aromatics from the aromatization reactions, olefins , and paraffins ranging from C5s to ... | https://en.wikipedia.org/wiki/Pyrolysis_gasoline |
Pyrolysis oil , sometimes also known as biocrude or bio-oil , is a synthetic fuel with few industrial applications and under investigation as substitute for petroleum . It is obtained by heating dried biomass without oxygen in a reactor at a temperature of about 500 °C (900 °F) with subsequent cooling, separation from ... | https://en.wikipedia.org/wiki/Pyrolysis_oil |
Pyrolytic chromium carbide coating ( PCC ) is a technology for protection and reworking of rapidly wearing parts of manufacturing equipment working in extreme environmental conditions, using vacuum deposition technology. Coating mechanical parts can help with problems of corrosion , adhering, high-temperature and mech... | https://en.wikipedia.org/wiki/Pyrolytic_chromium_carbide_coating |
Pyrometallurgy is a branch of extractive metallurgy . It consists of the thermal treatment of minerals and metallurgical ores and concentrates to bring about physical and chemical transformations in the materials to enable recovery of valuable metals. [ 1 ] Pyrometallurgical treatment may produce products able to be s... | https://en.wikipedia.org/wiki/Pyrometallurgy |
A pyrometer , or radiation thermometer , is a type of remote sensing thermometer used to measure the temperature of distant objects. Various forms of pyrometers have historically existed. In the modern usage, it is a device that from a distance determines the temperature of a surface from the amount of the thermal radi... | https://en.wikipedia.org/wiki/Pyrometer |
A substance is pyrophoric (from Ancient Greek : πυροφόρος , pyrophoros , 'fire-bearing') if it ignites spontaneously in air at or below 54 °C (129 °F) (for gases) or within 5 minutes after coming into contact with air (for liquids and solids). [ 1 ] Examples are organolithium compounds and triethylborane . Pyrophoric m... | https://en.wikipedia.org/wiki/Pyrophoricity |
Pyrophosphatases , also known as diphosphatases , are acid anhydride hydrolases that act upon diphosphate bonds. [ 1 ]
Examples include:
This EC 3.6 enzyme -related article is a stub . You can help Wikipedia by expanding it . | https://en.wikipedia.org/wiki/Pyrophosphatase |
In chemistry , pyrophosphates are phosphorus oxyanions that contain two phosphorus atoms in a P−O−P linkage. A number of pyrophosphate salts exist, such as disodium pyrophosphate ( Na 2 H 2 P 2 O 7 ) and tetrasodium pyrophosphate ( Na 4 P 2 O 7 ), among others. Often pyrophosphates are called diphosphates . The parent ... | https://en.wikipedia.org/wiki/Pyrophosphate |
Pyroprocessing (from Greek Πυρος = fire ) is a process in which materials are subjected to high temperatures (typically over 800 °C) in order to bring about a chemical or physical change. Pyroprocessing includes such terms as ore-roasting , calcination and sintering . Equipment for pyroprocessing includes kilns , ele... | https://en.wikipedia.org/wiki/Pyroprocessing |
Pyrosequencing is a method of DNA sequencing (determining the order of nucleotides in DNA) based on the "sequencing by synthesis" principle, in which the sequencing is performed by detecting the nucleotide incorporated by a DNA polymerase . Pyrosequencing relies on light detection based on a chain reaction when pyropho... | https://en.wikipedia.org/wiki/Pyrosequencing |
Pyroshock , also known as pyrotechnic shock , is the dynamic structural shock that occurs when an explosion or impact occurs on a structure. Davie and Bateman describe it as: "Pyroshock is the response of a structure to high frequency (thousands of hertz), high-magnitude stress waves that propagate throughout the stru... | https://en.wikipedia.org/wiki/Pyroshock |
A pyrotechnic composition is a substance or mixture of substances designed to produce an effect by heat, light, sound, gas/smoke or a combination of these, as a result of non-detonative self-sustaining exothermic chemical reactions. Pyrotechnic substances do not rely on oxygen from external sources to sustain the reac... | https://en.wikipedia.org/wiki/Pyrotechnic_composition |
A pyrotechnic heat source , also called heat pellet , is a pyrotechnic device based on a pyrotechnic composition with a suitable igniter . Its role is to produce controlled amount of heat. Pyrotechnic heat sources are usually based on thermite -like (or sometimes delay composition -like) fuel- oxidizer compositions wit... | https://en.wikipedia.org/wiki/Pyrotechnic_heat_source |
In pyrotechnics , a pyrotechnic initiator (also initiator or igniter ) is a device containing a pyrotechnic composition used primarily to ignite other, more difficult-to-ignite materials, such as thermites , gas generators , and solid-fuel rockets . The name is often used also for the compositions themselves.
Pyrotech... | https://en.wikipedia.org/wiki/Pyrotechnic_initiator |
Pyrotechnic stars are pellets of pyrotechnic composition which may contain metal powders, salts or other compounds that, when ignited, burn a certain color or make a certain spark effect. They are a part of all projectile -type fireworks . The most common is the aerial shell . When watching this firework, it will laun... | https://en.wikipedia.org/wiki/Pyrotechnic_star |
Pyrotol is a catalyst used in the industrial production of benzene through a process known as pyrolysis . It is a proprietary chromium - alumina catalyst manufactured by Clariant International (formerly known as Sud-Chemie) and licensed exclusively to CB&I Lummus Technology, Inc. It is completely unrelated to the expl... | https://en.wikipedia.org/wiki/Pyrotol_catalyst |
In statistics, Pyrrho's lemma is the result that if one adds just one extra variable as a regressor from a suitable set to a linear regression model, one can get any desired outcome in terms of the coefficients (signs and sizes), as well as predictions, the R-squared, the t-statistics, prediction- and confidence-interv... | https://en.wikipedia.org/wiki/Pyrrho's_lemma |
Pyrrole–imidazole polyamides (PIPs) are a class of polyamides have the ability to bind to minor grooves found in the DNA helix. [ 1 ] [ 2 ] Scientists are experimenting with it as a drug-delivery mode that can switch genes on and off, as well as epigenetic modification in gene therapy . [ 3 ]
This biotechnology articl... | https://en.wikipedia.org/wiki/Pyrrole–imidazole_polyamides |
Pyrrolizidine alkaloid sequestration by insects is a strategy to facilitate defense and mating. Various species of insects have been known to use molecular compounds from plants for their own defense and even as their pheromones or precursors to their pheromones. A few Lepidoptera have been found to sequester chemicals... | https://en.wikipedia.org/wiki/Pyrrolizidine_alkaloid_sequestration |
Pyruvate cycling commonly refers to an intracellular loop of spatial movements and chemical transformations involving pyruvate . Spatial movements occur between mitochondria and cytosol and chemical transformations create various Krebs cycle intermediates. In all variants, pyruvate is imported into the mitochondrion fo... | https://en.wikipedia.org/wiki/Pyruvate_cycling |
Pyruvate decarboxylation or pyruvate oxidation , also known as the link reaction (or oxidative decarboxylation of pyruvate [ 1 ] ), is the conversion of pyruvate into acetyl-CoA by the enzyme complex pyruvate dehydrogenase complex . [ 2 ] [ 3 ]
The reaction may be simplified as:
Pyruvate oxidation is the step that co... | https://en.wikipedia.org/wiki/Pyruvate_decarboxylation |
Pyruvate dehydrogenase complex ( PDC ) is a complex of three enzymes that converts pyruvate into acetyl-CoA by a process called pyruvate decarboxylation . [ 1 ] Acetyl-CoA may then be used in the citric acid cycle to carry out cellular respiration , and this complex links the glycolysis metabolic pathway to the citric ... | https://en.wikipedia.org/wiki/Pyruvate_dehydrogenase_complex |
Pyruvic acid (CH 3 COCOOH) is the simplest of the alpha-keto acids , with a carboxylic acid and a ketone functional group. Pyruvate , the conjugate base , CH 3 COCOO − , is an intermediate in several metabolic pathways throughout the cell.
Pyruvic acid can be made from glucose through glycolysis , converted back to ca... | https://en.wikipedia.org/wiki/Pyruvic_acid |
The Pyréolophore [ a ] ( French: [piʁeɔlɔfɔʁ] ) was an early internal combustion engine and the first made to power a boat. It was invented in the early 19th century in Chalon-sur-Saône , France, by the Niépce brothers: Nicéphore (who went on to invent photography ) and Claude . In 1807 the brothers ran a prototype in... | https://en.wikipedia.org/wiki/Pyréolophore |
The Pythagoras Award , or The Pythagoras Prize , or The Pitagor Prize (named after Pythagoras - a Greek philosopher, mathematician and scientist, Bulgarian : Награда Питагор), established in 2008, is an award given annually to Bulgarian nationals by the Ministry of Science and Education of Bulgaria in recognition for o... | https://en.wikipedia.org/wiki/Pythagoras_Award |
Pythagorean Triangles is a book on right triangles , the Pythagorean theorem , and Pythagorean triples . It was originally written in the Polish language by Wacław Sierpiński (titled Trójkąty pitagorejskie ), and published in Warsaw in 1954. [ 1 ] [ 2 ] Indian mathematician Ambikeshwar Sharma translated it into English... | https://en.wikipedia.org/wiki/Pythagorean_Triangles |
A Pythagorean cup (also known as a Pythagoras cup , greedy cup , cup of justice , anti greedy goblet or Tantalus cup [ citation needed ] ) is a practical joke device in a form of a drinking cup , credited to Pythagoras of Samos . When it is filled beyond a certain point, a siphoning effect causes the cup to drain its e... | https://en.wikipedia.org/wiki/Pythagorean_cup |
A Pythagorean quadruple is a tuple of integers a , b , c , and d , such that a 2 + b 2 + c 2 = d 2 . They are solutions of a Diophantine equation and often only positive integer values are considered. [ 1 ] However, to provide a more complete geometric interpretation, the integer values can be allowed to be negative an... | https://en.wikipedia.org/wiki/Pythagorean_quadruple |
The Pythagorean trigonometric identity , also called simply the Pythagorean identity , is an identity expressing the Pythagorean theorem in terms of trigonometric functions . Along with the sum-of-angles formulae , it is one of the basic relations between the sine and cosine functions.
The identity is
As usual, sin 2... | https://en.wikipedia.org/wiki/Pythagorean_trigonometric_identity |
A Pythagorean triple consists of three positive integers a , b , and c , such that a 2 + b 2 = c 2 . Such a triple is commonly written ( a , b , c ) , a well-known example is (3, 4, 5) . If ( a , b , c ) is a Pythagorean triple, then so is ( ka , kb , kc ) for any positive integer k . A triangle whose side lengths are ... | https://en.wikipedia.org/wiki/Pythagorean_triple |
In mathematics, and especially topology , a Pytkeev space is a topological space that satisfies qualities more subtle than a convergence of a sequence . They are named after E. G. Pytkeev, who proved in 1983 that sequential spaces have this property. [ 1 ]
Let X be a topological space. For a subset S of X let S denote... | https://en.wikipedia.org/wiki/Pytkeev_space |
In continuum mechanics , the Péclet number ( Pe , after Jean Claude Eugène Péclet ) is a class of dimensionless numbers relevant in the study of transport phenomena in a continuum. It is defined to be the ratio of the rate of advection of a physical quantity by the flow to the rate of diffusion of the same quantity dri... | https://en.wikipedia.org/wiki/Péclet_number |
Péter R. Surján (born August 30, 1955 [ 1 ] ) is a Hungarian theoretical chemist who is known for his research on application of the theory of second quantization in quantum chemistry .
In 2016 a festschrift from Theoretical Chemistry Accounts journal was published in his name [ 2 ] which is also published as a book i... | https://en.wikipedia.org/wiki/Péter_Surján |
In mathematics , a character sum is a sum ∑ χ ( n ) {\textstyle \sum \chi (n)} of values of a Dirichlet character χ modulo N , taken over a given range of values of n . Such sums are basic in a number of questions, for example in the distribution of quadratic residues , and in particular in the classical question of fi... | https://en.wikipedia.org/wiki/Pólya-Vinogradov_inequality |
The Pólya enumeration theorem , also known as the Redfield–Pólya theorem and Pólya counting , is a theorem in combinatorics that both follows from and ultimately generalizes Burnside's lemma on the number of orbits of a group action on a set . The theorem was first published by J. Howard Redfield in 1927. In 1937 it wa... | https://en.wikipedia.org/wiki/Pólya_enumeration_theorem |
The Pörner Group is an Austrian technology orientated, engineering and contracting company working on projects for the process industry . The headquarters are situated in Vienna , Austria. The group of companies specialises in various engineering industries such as oil refineries, chemical plants, petrochemical plants,... | https://en.wikipedia.org/wiki/Pörner_Group |
Pātīgaṇita is the term used in pre-modern Indian mathematical literature to denote the area of mathematics dealing with arithmetic and mensuration. [ 1 ] The term is a compound word formed by combining the words pātī and gaṇita . The former is a non-Sanskrit word meaning a "board" and the latter is a Sanskrit word mean... | https://en.wikipedia.org/wiki/Pātīgaṇita |
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