All articles starting with P

Polyploid cell

Polyploid cell: a cell with more than two complete chromosome sets, formed by endoreplication, cytokinesis failure, cell fusion, or mitotic slippage; common in liver, heart, and placenta, linked to larger cell size and to cancer risk.

Polyploidy

Polyploidy (whole-genome duplication) is the possession of more than two complete chromosome sets. Common in plants (2-4% of angiosperm speciation, 7% in ferns), rarer in animals, frequent in cancer (~30% of primary tumors), and present in normal tissues like hepatocytes.

PolyPlus Battery

PolyPlus Battery Company is a Berkeley, California battery developer founded in 1991, best known for its protected lithium electrode, a ceramic membrane enabling record-energy-density lithium-water, lithium-air, and lithium-seawater batteries.

Polypodiaceae

Polypodiaceae, the polypody family, is the largest fern family, about 65 genera and 1,650 species (over 4,000 with former Dryopteridaceae genera), cosmopolitan, mostly tropical, with creeping rhizomes, no indusium, and many epiphytes.

Polypodiales

Polypodiales, the polypod ferns, is the largest order of leptosporangiate ferns in class Polypodiopsida, about 82% of fern species, with six PPG suborders and a cavitation-catapult annulus for spore release.

Polypodium

Polypodium (polypody ferns), family Polypodiaceae, published by Linnaeus in 1753; creeping-rhizome epiphytic ferns with exindusiate sori, native from temperate Northern Hemisphere to Tropical America and Africa, about 225 species broadly, 46 accepted.

Polypodium glycyrrhiza

Polypodium glycyrrhiza, the licorice fern, is a Pacific Rim epiphytic fern of Polypodiaceae from Kamchatka and Alaska to California, summer deciduous on mossy bigleaf maples, with a sweet polypodoside rhizome chewed by Indigenous peoples.

Polypodium vulgare

Polypodium vulgare (common polypody) is a temperate fern of Polypodiaceae, type species of Polypodium, described by Linnaeus in 1753; an allotetraploid restricted to Europe, with rhizome used as a traditional EMA-listed expectorant.

Polypogon

Polypogon (rabbitsfoot grass, beard grass) is a genus of annual and perennial grasses in Poaceae, published by Desfontaines in 1798, with fluffy awned spike-like panicles, one-flowered deciduous spikelets, and a Mediterranean-centered distribution; the type species is P. monspeliensis.

Polypoid sinus degeneration

Polypoid sinus degeneration, also called Woakes' syndrome or Woakes' ethmoiditis, is recurrent nasal polyps with destruction of the nasal pyramid; ICD-11 CA0J.0, SNOMED 26808007, often non-eosinophilic with nasal broadening.

Polypora

Polypora is an extinct fenestrate bryozoan genus (M'Coy, 1844; type species P. dendroides) with fan-shaped, net-like calcite fronds, ranging Lower Devonian to Upper Permian worldwide; unrelated organisms share the species epithet polypora.

Polyporaceae

Polyporaceae, a family of bracket fungi in the order Polyporales (Basidiomycota), type genus Polyporus; largest polypore family with 103 genera and 1,170 species of wood-decaying, mostly white-rot fungi.

Polyporales

Polyporales: order of Basidiomycota fungi (formerly Aphyllophorales) of bracket fungi and wood decayers; saprophytic cellulose and lignin decomposers, 18 families per Justo et al. 2017, white and brown rot types, many medicinal species.

Polypore

Polypore, or bracket fungus, is a morphological group of Basidiomycete fungi with a poroid spore surface, mostly wood-decaying, spanning several orders including Polyporales; not a natural lineage, with about 400 European and 492 North American species.

Polyposis syndrome

Polyposis syndrome: hereditary conditions with multiple gastrointestinal polyps and elevated cancer risk, including FAP (APC, dominant), MAP (MUTYH, recessive), hamartomatous syndromes (PJS, JPS, PTEN), and serrated polyposis, the most common type.

Polyprion americanus

Polyprion americanus, the wreckfish (cherna, cernier commun), is a large long-lived Polyprionidae fish of temperate seas worldwide, reaching about 2 m and 100 kg, living up to 80 years, with pelagic juveniles drifting under floating objects and a quota-managed U.S. fishery on the Blake Plateau.

Polypropylene

Polypropylene (PP), also called polypro, is a thermoplastic polymer made by polymerizing propylene, one of the world's most widely produced plastics, used in packaging, automotive parts, fibers, and piping.

Polypropylene carbonate

Polypropylene carbonate (PPC) is a biodegradable thermoplastic polycarbonate made by copolymerizing carbon dioxide with propylene oxide, first synthesized in 1969 and used in packaging films and foams.

Polypropylene fiber

Polypropylene fiber is a synthetic fiber made by melt spinning polypropylene. It is the lightest commercial textile fiber, absorbing almost no moisture, and is used in ropes, carpets, and nonwovens.

Polypropylene glycol

Polypropylene glycol, also called polypropylene oxide, is a colorless viscous polyether made by polymerizing propylene oxide, used mainly as the polyol in polyurethanes and as a defoamer and lubricant.

Polypropylene recycling

Polypropylene recycling recovers value from waste polypropylene (PP) through mechanical reprocessing and chemical routes like hydrogenolysis, hydrocracking, and selective oxidation. PP lacks hydrolysable linkages, so closed-loop recycling is largely out of reach.

Polypropylene separator

A polypropylene separator is a microporous polypropylene membrane between a lithium-ion battery's electrodes that prevents short circuit while letting lithium ions pass, known for low cost and thermal shutdown.

Polypropylene upcycling

Polypropylene upcycling is the set of chemical and catalytic processes converting waste polypropylene into higher-value products such as fuels, surfactants, and monomers, mainly through pyrolysis, hydrogenolysis, and oxidation.

Polyps of small intestine

Polyps of small intestine (ICD-11 DA98) are benign tissue masses protruding into the small-bowel lumen: hamartomas, hyperplastic, inflammatory fibroid polyps, and lymphoid hyperplasia, detected by capsule endoscopy and treated via device-assisted enteroscopy.

Polyptychoceras

Polyptychoceras (Yabe, 1927), type species P. pseudogaultinum, a heteromorph ammonite of the Diplomoceratidae from the Santonian–Campanian of Hokkaido, Sakhalin and beyond, with a paper-clip shell of parallel shafts joined by U-shaped tubes.

Polypyrrole

Polypyrrole (PPy) is an intrinsically conducting organic polymer formed by oxidative coupling of pyrrole units, first synthesized in 1915 and valued for conductivity, stability, and biocompatibility.

Polyrhythm

Polyrhythm: two or more nonharmonically related rhythmic patterns, such as 3:2 or 4:5, played simultaneously within one shared cycle. Distinct from polymeter, cross-rhythm, and hemiola; foundational in West African drumming and used by Brahms, Stravinsky, Carter, and Brubeck.

Polyrotaxane

A polyrotaxane is a polymer with a mechanically interlocked architecture, in which macrocyclic rings are threaded onto a linear axle and cannot slip off because bulky stopper groups cap the ends.

Polyrrenia

Polyrrenia (Πολυρρήνια, Polyrrhenia) was an ancient Doric Cretan polis in the Kissamos hinterland, western Crete, a fortified Hellenistic power with its own coinage (ca. 330 BC to AD 41), treaties with Melos and Phalasarna, and decline after the 2nd century AD.