All articles starting with P

Polyacetylene

Polyacetylene, formula (CH)x, is the simplest conjugated polymer, first polymerized in 1958; doped films conducted electricity, inspiring conducting polymers and the 2000 Nobel Prize in Chemistry.

Polyacrylamide, also known as linear polyacrylamide, is a water-soluble synthetic polymer of acrylamide monomers. It is used industrially as a flocculant in water treatment, a soil conditioner, and a friction reducer in hydraulic fracturing.

Polyacrylamide gel electrophoresis

Polyacrylamide gel electrophoresis (PAGE, ポリアクリルアミドゲル電気泳動法) separates proteins in an acrylamide gel matrix. Variants include SDS-PAGE (Laemmli 1970), native, urea, blue-native, and tricine PAGE, used for molecular weight and purity analysis.

Polyacrylamide hydrogel

Polyacrylamide hydrogel (PAAG) is a water-based polymer gel developed in Ukraine in the late 1980s as a permanent injectable soft tissue filler, used widely for breast augmentation.

Polyacrylic acid

Polyacrylic acid (PAA), known in crosslinked grades as carbomers or Carbopols, is a synthetic water-soluble polymer whose sodium salt forms superabsorbent polymers in disposable diapers.

Polyacrylonitrile

Polyacrylonitrile (PAN) is a synthetic, semicrystalline polymer made by polymerizing acrylonitrile. First spun into fibers in 1938, it is the precursor for roughly 96% of the carbon fiber market.

Sep 29, 2026

Polyaddition

Polyaddition is a step polymerization in which monomers with two or more functional groups add together, forming polymer with no low-molar-mass by-product; polyurethane is the best-known example.

Oct 21, 2026

Polyadenylate-binding protein/Hyperplastic disc protein, C-terminal

MLLE/PABC (InterPro IPR002004, Pfam PF00658), the C-terminal domain of poly(A)-binding protein and hyperplastic disc protein UBR5/EDD; a ~70-residue 4-5 helix peptide-binding domain recognizing PAM2 motifs in translation and mRNA-decay factors.

Polyadenylation

Polyadenylation, also called poly(A) tailing, is the non-template addition of adenosines to RNA 3' ends after transcription, producing tails up to 250-300 nucleotides that enable mRNA export, stability, and translation, with alternative polyadenylation affecting over 60% of human genes.

PolyAI

PolyAI is a London-based enterprise conversational-AI company founded in 2017 as a University of Cambridge spinout, building voice agents that answer customer service calls for enterprises.

Polyakov action

The Polyakov action is the two-dimensional field-theory form of the bosonic string worldsheet action, introduced by Alexander Polyakov in 1981 and classically equivalent to the Nambu–Goto action.

Polyakov loop

The Polyakov loop is a Wilson loop winding around the thermal time direction of finite-temperature lattice gauge theory, measuring the free energy of an isolated static quark.

Polyalphaolefin

Polyalphaolefin (PAO) is a synthetic hydrocarbon base oil made by oligomerizing alpha-olefins such as 1-decene, the only API Group IV base stock, used in high-performance automotive, industrial, and aviation lubricants.

Oct 21, 2026

Polyalthia

Polyalthia (Blume, 1830) is a genus of about 100 accepted species of trees and shrubs in Annonaceae, native from Madagascar to tropical Asia and NE Australia, polyphyletic historically, with medicinal clerodane diterpenoids and alkaloids.

Polyaluminium chloride

Polyaluminium chloride, also known as aluminum hydroxy chloride or basic aluminum chloride, is a coagulant used to clarify drinking water and treat wastewater, first industrialized in Japan in 1967.

Polyamide

A polyamide is a polymer containing carboxamide groups as backbone linkages, a class that includes the aliphatic nylons such as PA6 and PA66 and the aromatic aramids like Kevlar.

Polyamide 56

Polyamide 56 (PA56) is a bio-based nylon made from 1,5-pentanediamine produced by fermenting biomass and from adipic acid, regarded as the best bio-based replacement for the petroleum-based workhorse PA66.

Oct 21, 2026

Polyamine biosynthesis domain

Polyamine biosynthesis (PABS) domain, PROSITE PS51006 / InterPro IPR030374: a conserved two-subdomain protein domain in evolutionarily related enzymes making putrescine, spermidine, and spermine.

Polyamine catabolism and regulation

Polyamine catabolism and regulation is the set of reactions lowering cellular spermine and spermidine by acetylation, oxidation, and secretion, with antizyme feedback and transport keeping pools within narrow limits.

Polyamory

Polyamory is consensual non-monogamy involving multiple loving relationships with everyone's knowledge and consent, distinct from swinging and polygamy; coined in 1992, practiced by roughly 1 in 9 US singles, with satisfaction comparable to monogamy.

Polyana Viana

Polyana Viana, "Dama de Ferro" (Iron Lady), Brazilian UFC women's strawweight born 1992 in Pará; former Jungle Fight champion, 13-9 record with all 13 wins by finish, jiu-jitsu brown belt.

Polyandry

Polyandry: one woman or female with multiple husbands or mates. Two forms, fraternal (Tibetan brothers sharing a wife) and non-fraternal (Nair). Rare worldwide, 53 surveyed non-classical societies, declining and legally unrecognized in India.

Polyandry in India

Polyandry in India is the practice of one woman married to more than one man at once, recorded from ancient times, chiefly in fraternal form in the Himalayas.

Polyaniline

Polyaniline (PANI), historically called aniline black, is a conducting organic polymer formed by linking aniline monomers; studied since 1834, its conducting emeraldine salt form is used in anticorrosive coatings, sensors, and energy-storage electrodes.

Polyanion cathode

A polyanion cathode is a battery positive-electrode material in which covalent polyanionic groups such as phosphates raise voltage but lower capacity, with olivine LiFePO₄ its commercial anchor.

Polyanionic sodium-ion cathode

A polyanionic sodium-ion cathode is a sodium-ion battery positive electrode built from tetrahedral anion units like phosphate or sulfate, one of three main cathode families.

Polyarnaya Zvezda

Polyarnaya Zvezda (Полярная звезда, "The Polar Star") was a popular Russian literary almanac edited in Saint Petersburg by Kondraty Ryleev and Alexander Bestuzhev, appearing annually from 1823 to 1825.

Polyarteritis nodosa

Polyarteritis nodosa (PAN), also periarteritis nodosa, Kussmaul-Maier disease: rare ANCA-negative necrotizing vasculitis of medium-sized arteries, first described 1866; treated with glucocorticoids plus cyclophosphamide in severe disease; HBV-associated and DADA2 forms now separated.

Polyarticular rheumatoid-factor-negative juvenile idiopathic arthritis

Polyarticular rheumatoid-factor-negative juvenile idiopathic arthritis (RF-negative pJIA) is a subtype of juvenile idiopathic arthritis in which arthritis affects five or more joints and rheumatoid factor tests are negative.