All articles starting with N

Noncovalent catalysis

Noncovalent catalysis is a mode of catalysis in which catalysts, typically small organic molecules, aromatic scaffolds, or enzymes, stabilize transition states through weak noncovalent interactions rather than covalent or coordination bonds.

Oct 15, 2026

Noncovalent interaction analysis (NCI)

Noncovalent interaction analysis (NCI) is a computational method introduced in 2010 that visualizes weak interactions, such as hydrogen bonds and steric repulsion, directly from electron density.

Noncovalent interactions

Noncovalent interactions are weak attractive or repulsive forces between molecules that do not share electrons, including hydrogen bonds and dispersion forces, typically 1 to 10 kcal/mol.

Noncustodial parent

Noncustodial parent: the separated or divorced parent without primary physical custody, typically paying child support and exercising parenting time. Covers US custody terminology, federal support guidelines, and the rise of shared placement.

Oct 20, 2026

Noncyclic pelvic pain

Noncyclic pelvic pain (ICD-11 GA34.21) is chronic pelvic pain in women not tied to the menstrual cycle, located in the pelvis, abdominal wall, lower back, or buttocks; prevalence estimates range widely and treatment evidence is limited.

Nondestructive testing

Nondestructive testing (NDT), also called nondestructive evaluation (NDE), is the evaluation of materials, components, and structures for flaws without damaging them, essential for pipelines, power plants, and safety parts.

Nondeterministic algorithm

A nondeterministic algorithm, also called nondeterministic computation, is a theoretical algorithm with multiple possible steps that always takes the right or best one, underlying the class NP.

Nondeterministic finite automaton

A nondeterministic finite automaton (NFA) is a finite-state machine whose transitions can lead to several next states at once; it recognizes exactly the regular languages, like a deterministic automaton.

Nondeterministic Turing machine

A nondeterministic Turing machine is a mathematical model of computation that can choose among several possible transitions at each step, and it underlies the complexity class NP.

Nondisjunction

Nondisjunction: failure of homologous chromosomes or chromatids to separate in meiosis or mitosis, producing aneuploidy; mostly maternal, strongly age-dependent, and the main cause of trisomies such as Down syndrome.

Nondualism

Nondualism (Sanskrit advaita, "not two") is a family of philosophical and religious positions denying the fundamental two-ness of subject and object. Distinct from monism and idealism, it spans Advaita Vedanta, Buddhist emptiness, Sufi and Christian parallels, and cognitive-science work on nondual awareness.

Oct 10, 2026

Nondurable good

A nondurable good is a good with an average useful life of less than 3 years in US national accounts, such as food, gasoline, and clothing.

None of the above

None of the above (NOTA), also called a blank or against-all vote, is a ballot option that lets voters reject all candidates rather than choose any of them.

None of the above (India)

None of the Above (NOTA) is India's ballot option, introduced after the 2013 PUCL Supreme Court judgment, letting voters reject all candidates secretly; it cannot void results, polling 0.99% in 2024.

None of This Is True

None of This Is True is a 2023 psychological thriller by Lisa Jewell about podcaster Alix Summer and her unsettling "birthday twin" Josie Fair; an instant NYT bestseller with a Netflix film adaptation in development.

None used on labelling for supply through UN agencies. Also marketed with labelled commercial name BE Td

WHO-prequalified diphtheria-tetanus (dT) vaccine, product FVP-P-399, by Biological E. Limited, India, marketed as BE Td; unbranded 20-dose vials for UN agency supply, prequalified 9 March 2020 under CDSCO oversight.

Oct 20, 2026

None used on labelling for supply through UN agencies. Also marketed with labelled commercial name ComBE Five.

ComBE Five (Liquid) is a WHO-prequalified liquid pentavalent DTP-HepB-Hib vaccine from Biological E. Limited, India, prequalified 27 November 2014, given intramuscularly to infants from 6 weeks of age.

None used on labelling for supply through UN agencies. Also marketed with labelled commercial name TRIPVAC

TRIPVAC is Biological E. Limited's WHO-prequalified whole-cell DTP vaccine (effective 31 July 2014), unlabelled for UN agency supply, liquid single-dose vials, thiomersal-preserved, stored 2-8°C; two lots were banned in Ukraine in 2026.

Nonequilibrium candidate Monte Carlo

Nonequilibrium candidate Monte Carlo is a Markov chain Monte Carlo method, introduced in 2011, that drives molecular systems out of equilibrium and accepts moves based on work performed.

Nonetheless

Nonetheless is Pet Shop Boys' fifteenth studio album, released April 26, 2024 on Parlophone; produced by James Ford with analog synths and the Elysian Collective, it reached number two in the UK and drew wide acclaim.

Nonfinite verb

Nonfinite verb: a verb form not fully inflected for tense, aspect, modality, number, or person, as with infinitives, participles, gerunds, and converbs; nonfinite clauses lack primary tense or agreement and are subordinate.

Nonfluoride enamel opacities

Nonfluoride enamel opacities are developmental enamel defects, white to yellow-brown areas of altered translucency not caused by fluoride, occurring in low-fluoride areas; ICD-11 code DA07.1; MIH is the main modern subset.

Nonformal learning

Nonformal learning is organized, intentional learning outside the formal education system, between formal schooling and informal learning; typically short courses and workplace training whose outcomes are validated through RPL and VINFL frameworks.

Nonfullerene tandem organic solar cells

Nonfullerene tandem organic solar cells are stacked photovoltaic devices whose organic sub-cells use non-fullerene acceptors to harvest complementary parts of the solar spectrum, reaching over 21% efficiency.