All articles starting with N
16,460 articles
N-gram
An n-gram is a contiguous sequence of n items from a text or speech stream, and n-gram models were the dominant form of statistical language modeling for decades.
N-gram language model
An n-gram language model is a statistical model that estimates the probability of a word sequence by counting how often word sequences appear in training data.
N-heterocyclic carbene
An N-heterocyclic carbene (NHC) is a cyclic molecule containing a carbene carbon and a ring nitrogen, widely used as a ligand for transition-metal catalysts and as an organocatalyst.
N-heterocyclic carbene catalysis
N-heterocyclic carbene catalysis, also known as heterocyclic carbene catalysis, is an organocatalysis method in which carbenes from azolium salts invert carbonyl reactivity, enabling benzoin, Stetter, and annulation reactions.
N-heterocyclic carbene radical catalysis
N-heterocyclic carbene radical catalysis is a branch of organocatalysis in which an N-heterocyclic carbene generates radical intermediates through single-electron transfer, inspired by thiamine diphosphate enzymes and developed since 2008.
N-hydroxyphthalimide esters
N-hydroxyphthalimide esters, also called NHPI esters or N-(acyloxy)phthalimides, are redox-active esters of carboxylic acids that release alkyl radicals and carbon dioxide on single-electron reduction, and are a standard radical feedstock in modern organic synthesis.
N-Joi
N-Joi is an English electronic dance and rave act formed in 1989 by Mark Franklin and Nigel Champion, best known for the 1991 hit "Anthem".
N-linked glycosylation
N-linked glycosylation (N-glycosylation) is the attachment of a preassembled oligosaccharide to asparagine in Asn-X-Ser/Thr sequons in the ER, catalyzed by oligosaccharyltransferase using a dolichol-linked Glc3Man9GlcNAc2 donor; found in all three domains of life and central to protein folding and quality control.
N-Methyl-2-pyrrolidone
N-Methyl-2-pyrrolidone (NMP), also called 1-methyl-2-pyrrolidone or N-methylpyrrolidone, is a water-miscible polar aprotic solvent used in petrochemical extraction, polymer processing, and battery manufacturing, and restricted in the European Union as a reproductive toxicant.
N-Methyl-D-glucamine
N-Methyl-D-glucamine, widely known as meglumine, is an amino sugar derived from sorbitol whose main use is as a salt-forming counterion for acidic drugs, most prominently radiographic contrast media.
N-Methyl-N-nitrosourea
N-Methyl-N-nitrosourea (MNU), also called N-nitroso-N-methylurea, is an N-nitrosourea alkylating agent classified as probably carcinogenic to humans, used in research to induce rat mammary cancer and retinal degeneration.
N-Methyl-N'-nitro-N-nitrosoguanidine
N-Methyl-N'-nitro-N-nitrosoguanidine (MNNG) is a synthetic N-nitroso compound that directly methylates DNA. Used for decades to study DNA repair, it induced the 1970s discovery of the adaptive response in E. coli.
N-Methylaniline
N-Methylaniline, also called monomethyl aniline or NMA, is a secondary aromatic amine, an oily liquid used in organic synthesis and as a gasoline octane booster since the 1920s.
N-Methylethanolamine
N-Methylethanolamine, also called methyl beta-hydroxyethylamine, is a viscous, colorless, water-miscible secondary amino alcohol and strong base used in acid gas scrubbing, coatings, surfactants, and pharmaceutical synthesis.
N-Methylformamide
N-Methylformamide, or NMF, is a colorless liquid organic amide (CH₃NHCHO) and polar protic solvent more polar than water, intermediate between formamide and the common solvent DMF.
N-Methylmorpholine N-oxide
N-Methylmorpholine N-oxide (NMMO, also NMO) is a cyclic tertiary amine oxide used as the direct solvent for cellulose in the lyocell process and as a co-oxidant in alkene dihydroxylation.
N-Nitrosodiethylamine
N-Nitrosodiethylamine, also called diethylnitrosamine or NDEA, is a volatile nitrosamine and extensively studied carcinogen that causes tumors in all tested animals; since 2018 it has been monitored as a drug impurity.
N-Nitrosodimethylamine
N-Nitrosodimethylamine, also known as dimethylnitrosamine or NDMA, is a water-miscible nitrosamine classified as a probable human carcinogen, formed during water disinfection and found as an impurity in recalled drugs.
N-Nitrosonornicotine
N-Nitrosonornicotine (NNN) is a tobacco-specific nitrosamine, formed from nornicotine during tobacco curing, that causes esophageal and oral tumors and is classified by IARC as carcinogenic to humans.
N-of-1 trial
An N-of-1 trial is a randomized, usually blinded multiple-crossover experiment in a single patient, named by Gordon Guyatt and colleagues in a 1986 New England Journal of Medicine paper.
N-path filter
An N-path filter is a radio-frequency bandpass filter built from switches and capacitors driven by N clock phases, giving CMOS receivers a high-Q, widely tunable filter without off-chip components.
N-Phenyl-1-naphthylamine
N-Phenyl-1-naphthylamine, usually sold as PANA or antioxidant A and known in China as T531, is a crystalline arylamine used as an antioxidant in rubber compounds and lubricating oils.
N-Phenylcarbazole
N-Phenylcarbazole, also known as 9-phenyl-9H-carbazole, is an aromatic amine with a phenyl ring attached to carbazole's nitrogen atom, valued in organic electronics for its high triplet energy and use as an OLED host material.
N-po generation (N포 세대)
N-po generation (N포 세대) is a South Korean neologism for youth who give up an indefinite number of life goals, extending the 3-po, 5-po, and 7-po ladder of renouncing dating, marriage, children, housing, relationships, and hope.
n-propyl acetate
n-Propyl acetate, also 1-propyl acetate, is the acetate ester of acetic acid and propan-1-ol, a flammable liquid with a fruity, pear-like odor used as a solvent.
n-Propylamine
n-Propylamine, also known as propan-1-amine, is the straight-chain primary aliphatic amine of propane, a clear, highly flammable liquid with an ammonia-like odor used mainly as an intermediate in agricultural chemicals and pharmaceuticals.
N-ray
N-rays were a purported form of radiation announced in 1903 by French physicist René Blondlot, debunked in 1904 by Robert W. Wood and now a classic case of pathological science.
N-sphere
An n-sphere, also called a hypersphere, is the set of points at a fixed distance from a center in (n + 1)-dimensional space; the 1-sphere is the circle.
N-terminus
The N-terminal region (N-terminus) of a protein is the chain end bearing a free amino group, starting with an initiator methionine and modified by acetylation, methionine excision, and degradation-signaling enzymes.
N-Town Plays
The N-Town Plays, once known as the Ludus Coventriae or Hegge plays, are a cycle of East Anglian biblical dramas copied around 1468 in a single surviving manuscript.