All articles starting with N

N tetradecylacetate

N tetradecylacetate (myristyl acetate, CAS 638-59-5, C16H32O2) is a straight-chain acetate ester used as a low-risk semiochemical pheromone component in mating disruption of codling moth on pome and stone fruit and tree nuts in the US and EU.

n_TOF

n_TOF, or Neutron Time Of Flight, is a pulsed neutron time-of-flight facility at CERN, operating since 2001, studying neutron-nucleus interactions from meV to GeV energies.

N-1 criterion

The N-1 criterion is a power system reliability rule requiring that the grid remain secure, within emergency ratings and stability limits, after any single element's loss.

N-2 (rocket)

The N-2, also written N-II, was a three-stage Japanese satellite launch vehicle developed by NASDA using American Delta rocket technology, launching eight satellites successfully between 1981 and 1987.

N-Acetyl-D-Galactosamine

N-Acetyl-D-Galactosamine, known as GalNAc, is an amino sugar derived from galactose that occurs in humans and E. coli, initiates mucin-type O-glycosylation, and delivers siRNA drugs to hepatocytes.

N-acetyl-gamma-glutamyl-phosphate reductase

N-acetyl-gamma-glutamyl-phosphate reductase (AGPR, EC 1.2.1.38, gene argC) is an NADPH-dependent enzyme catalyzing step 3 of arginine biosynthesis, reducing N-acetylglutamyl phosphate to N-acetylglutamate semialdehyde; distinct from the liver asialoglycoprotein receptor also abbreviated AGPR.

N-acetyl-gamma-glutamyl-phosphate reductase, type 1

N-acetyl-gamma-glutamyl-phosphate reductase, type 1 (AGPR_type-1, IPR000706) is the InterPro family for EC 1.2.1.38, the NADP-dependent argC enzyme catalyzing the third step of arginine biosynthesis from glutamate, including the LysY lysine-pathway relative.

N-Acetyl-L-Aspartic Acid

N-Acetyl-L-aspartic acid (NAA) is an acetylated derivative of L-aspartate, abundant in the vertebrate brain and used as a marker of neuronal health on magnetic resonance spectroscopy.

N-Acetyl-Neuraminic Acid

N-Acetylneuraminic acid, also called NANA or sialic acid, is a nine-carbon sugar that caps cell-surface glycans in vertebrates and mediates viral attachment and immune signaling.

N-Acetylglucosamine

N-Acetylglucosamine (GlcNAc) is an amino sugar derivative of glucose that forms the polymer chitin in fungal cell walls and arthropod exoskeletons and occurs in bacterial peptidoglycan and mammalian glycoproteins.

N-Acetylglutamate synthase

N-Acetylglutamate synthase (NAGS, EC 2.3.1.1) is a mitochondrial liver enzyme making N-acetylglutamate, the activator of CPSI in the urea cycle; arginine activates it in mammals but inhibits microbial NAGS, and its inherited deficiency causes hyperammonemia treated with carglumic acid.

N-Acetylglutamic acid

N-Acetylglutamic acid (NAG), first intermediate of arginine biosynthesis in microbes and plants and essential allosteric activator of CPS1 in the mammalian urea cycle; deficiency treated with carglumic acid.

N-acetylmuramoyl-L-alanine amidase domain

N-acetylmuramoyl-L-alanine amidase domain (NALAA, EC 3.5.1.28): zinc-dependent peptidoglycan hydrolase domain cleaving the MurNAc–L-Ala bond; families Amidase_2, Amidase_3, Amidase_5 in bacteria, phage endolysins, and human PGLYRP2.

N-acetyltransferase

N-acetyltransferase (NAT): enzyme transferring an acetyl group from acetyl-CoA to a primary amine; the GNAT superfamily (named after yeast Gcn5) has over 870,000 members spanning antibiotic resistance, histone acetylation, and N-terminal protein acetylation.

N-Acyl homoserine lactone

N-Acyl homoserine lactones (AHLs) are small bacterial signaling molecules, each a homoserine lactone ring with an acyl side chain, that Gram-negative bacteria use for quorum sensing to regulate biofilms, virulence, and bioluminescence.

n-Amyl alcohol

n-Amyl alcohol, also called 1-pentanol or n-pentyl alcohol, is a straight-chain five-carbon primary alcohol, a colorless flammable liquid with a fusel-like odor used as a solvent and intermediate.

N-back

N-back: a 1958 working memory task by Kirchner in which participants judge whether the current stimulus matches one n trials back. Variants include visual, auditory, and dual n-back. Correlates only weakly (r ≈ .20) with complex span tasks and activates frontoparietal networks.

N-BEATS

N-BEATS is a deep neural architecture for univariate time series forecasting, introduced in 2019 by researchers at Element AI and Mila including Yoshua Bengio, and published at ICLR 2020.

N-BK7

N-BK7 is a borosilicate crown optical glass made by SCHOTT AG and widely used for visible and near-infrared lenses, prisms, and windows; its refractive index is 1.51680.

N-body problem

The N-body problem, also called N-body mechanics, is the problem of predicting the motion of N particles interacting through gravity, solvable analytically only for up to two bodies.

N-body simulation

An N-body simulation is a numerical calculation of many bodies interacting through gravity, the standard astrophysical tool for problems from planetary orbits to cosmic structure formation.

N-Bromosuccinimide

N-Bromosuccinimide (NBS) is a crystalline organic brominating reagent used chiefly for selective allylic and benzylic bromination, the Wohl–Ziegler reaction, introduced by Ziegler in the late 1930s.

n-Butyl acetate

n-Butyl acetate, also called butyl ethanoate, is a colorless, flammable liquid ester with a fruity odor, used mainly as a solvent for coatings and lacquers.

N-Butyllithium

N-Butyllithium (n-BuLi) is an organolithium compound sold as solutions in hydrocarbon solvents, used as a strong base and to initiate anionic polymerization of butadiene, isoprene, and styrene.

N-carrier

N-carrier was a Bell System family of analog carrier telephone systems for short-haul transmission over twisted-pair cable, introduced in 1950 and later displaced by digital T-carrier.

N-Dubz

N-Dubz are a British hip hop and pop trio from Camden, London (Dappy, Tulisa, Fazer), formed in 2000, with four MOBO Awards, the 2009 UK number-one "Number 1" with Tinchy Stryder, and the 2023 comeback album Timeless.

N-end rule

N-end rule: protein half-life is set by the N-terminal residue; discovered 1986 by Varshavsky in yeast, implemented by N-recognins (Ubr1-5, PRT1/PRT6, ClpS) as N-degron pathways mediating oxygen/NO sensing and Johanson-Blizzard syndrome.

N-Ethyl-N-nitrosourea

N-Ethyl-N-nitrosourea (ENU), also called 1-ethyl-1-nitrosourea, is an alkylating N-nitrosourea compound and potent mutagen and carcinogen, used since the 1970s as the standard mutagen for forward genetic screens in mice.

N-ethylcarbazole

N-ethylcarbazole is a nitrogen heterocyclic compound used as a liquid organic hydrogen carrier whose hydrogenated form stores 5.8 wt% hydrogen, releasable at 180–225 °C, well below hydrocarbon carriers.