All articles starting with P
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Pericyclus
Pericyclus is an extinct genus of goniatitid ammonoid cephalopods in the family Pericyclidae, with type species P. princeps, restricted to the early Late Tournaisian around 350 Ma.
Pericyte
Pericytes are mural cells embedded in the basement membrane of capillaries and microvessels, wrapping endothelial cells. Also called Rouget cells; they regulate blood flow, angiogenesis, and the blood-brain barrier, and lack a single specific marker.
Peridier (Martian crater)
Peridier, a 94.21-km impact crater on Mars at 25.51°N 83.91°E in the Syrtis Major quadrangle, named 1973 for French astronomer Julien Peridier (1882-1967); shows fluvial channels, inverted ridges, and early Hesperian age.
Peridinium
Peridinium is a genus of armored dinoflagellates, single-celled protists enclosed in cellulose plates, best known for spring blooms of P. gatunense in Lake Kinneret, Israel.
Peridot
Peridot, also known as chrysolith, is the gem-quality yellowish-green variety of the mineral olivine, prized for its intrinsic iron-derived color and found in lavas and meteorites.
Peridotite
Peridotite is a coarse-grained ultramafic igneous rock rich in olivine, making up most of the Earth's upper mantle and reaching the surface in xenoliths and ophiolites.
Peridynamics
Peridynamics is a nonlocal continuum theory and simulation method introduced by Stewart A. Silling in 2000, in which fracture emerges from bond breaking rather than a separate crack-tracking algorithm.
Periegesis
Periegesis (ancient Greek: "a leading around") is a genre of ancient Greek travel writing describing a region place by place, best known from Pausanias' second-century CE Description of Greece.
Periendocarditis
Periendocarditis, also called acute endopericarditis, is simultaneous inflammation of the endocardium and pericardium, classified as ICD-11 code BB42 under acute or subacute endocarditis and ICD-10 I33.9.
Perifosine
Perifosine (KRX-0401, D-21266), an oral alkylphospholipid Akt inhibitor derived from miltefosine, tested in phase 3 trials for multiple myeloma and colorectal cancer; development ended after failed endpoints and withdrawn orphan designations.
Perifoveal exudative vascular anomalous complex
Perifoveal exudative vascular anomalous complex (PEVAC, also PVAC) is a rare idiopathic large aneurysmal lesion of the deep retinal capillary plexus near the fovea, diagnosed by exclusion, poorly responsive to anti-VEGF, distinct from type 3 MNV and MacTel.
Periglomerular cell
Periglomerular cell (PG cell, juxtaglomerular interneuron): small GABAergic interneuron surrounding olfactory bulb glomeruli, soma 5–10 µm, uniglomerular dendrites, dendrodendritic inhibition of mitral/tufted cells, dopaminergic TH+ subtype, adult-born, distinct from renal periglomerular usage.
Périgord
Périgord, also called Dordogne, is a historic province of southwest France corresponding to the Dordogne department in Nouvelle-Aquitaine, divided into noir, blanc, vert, and pourpre regions, known for prehistoric sites, castles, and foie gras.
Périgueux
Périgueux, prefecture of the Dordogne department in Nouvelle-Aquitaine, France; ancient Gallo-Roman Vesunna on the Isle river. 29,055 inhabitants (2023), Saint-Front Cathedral UNESCO-listed, Vesunna museum by Jean Nouvel.
Périgueux Roman amphitheater
Périgueux Roman amphitheater (amphithéâtre de Périgueux), the 140 x 116 m, 18,000-seat amphitheater of Gallo-Roman Vesunna in Dordogne, France; solid structure, no basement, later rampart bastion, now the Jardin des Arènes.
Perihelion precession of Mercury
The perihelion precession of Mercury is the gradual rotation of the planet's closest point to the Sun; about 43 arcseconds per century remained unexplained until Einstein's 1915 general relativity.
Perikatan Nasional
Perikatan Nasional (PN, National Alliance) is a Malay-based political coalition in Malaysia, formed around Prime Minister Muhyiddin Yassin in 2020 and the main opposition bloc since 2022.
Periklis Kakousis
Periklis Kakousis (Περικλής Κακούσης, 1879–1939), Greek weightlifter from Aegina and Panellinios GS member; won the 1904 St. Louis Olympic two-hands lift gold with 111.70 kg, first Greek Olympic weightlifting title, later a US professional wrestler.
Perilipin
Perilipin (PLIN1) is the major lipid droplet surface protein of adipocytes, discovered in 1991 in Constantine Londos's lab; it gates lipase access to stored triacylglycerol and founded the five-member PLIN1-5 protein family.
Perilipin-1
Perilipin-1 (PLIN1, formerly perilipin or PERI) is a 522-amino-acid lipid droplet coating protein of adipocytes and steroidogenic cells that gates lipolysis via PKA phosphorylation; frameshift variants cause familial partial lipodystrophy type 4.
Perilla
Perilla, a monotypic aromatic mint genus (Perilla frutescens) from subtropical Asia; cultivated as shiso, Korean perilla leaf, and perilla oilseed; six chemotypes, perillaldehyde culinary type, EFSA genotoxicity concern.
Perilla frutescens
Perilla frutescens (shiso, Zisu, beefsteak plant), an East Asian mint-family herb grown as culinary herb and omega-3-rich oilseed; chemotypes differ in safety, with perilla ketone toxic to livestock.
Perillaldehyde
Perillaldehyde, also called perillyl aldehyde, is a natural monoterpene aldehyde that gives perilla (shiso) leaves and citrus peel their characteristic pungent aroma and is used as a flavoring.
Perilloor Premier League
Perilloor Premier League (പേരില്ലൂർ പ്രീമിയർ ലീഗ്) is a 2024 Malayalam comedy web series on Disney+ Hotstar, directed by Praveen Chandran, written by Deepu Pradeep, starring Nikhila Vimal as Malavika, a reluctant village panchayat president.
Perimenopop
Perimenopop is Sophie Ellis-Bextor's eighth studio album, a pop-disco record released September 12, 2025 on Decca Records; its title, coined as a joke with co-writer Hannah Robinson, fuses perimenopause with pop, and it peaked at number 5 on the UK Albums Chart.
Perimeter
Perimeter is the total length of the boundary of a closed geometric figure; for a polygon it is the sum of side lengths, and for a circle it is the circumference.
Perimeter 81
Perimeter 81 is an Israeli cloud and network security company founded in 2018 in Tel Aviv by Sagi Gidali and Amit Bareket, acquired by Check Point in 2023.
Perimeter control (traffic)
Perimeter control, also called gating or perimeter flow control, is a network-level traffic management strategy that uses boundary traffic signals to limit vehicles entering a region, keeping it productive.
Perimeter frame (motorcycle)
The perimeter frame, also called the twin-spar frame, is a motorcycle chassis of two beams on each side of the engine, standard on modern sport bikes.
Perimeter Institute for Theoretical Physics
The Perimeter Institute for Theoretical Physics is an independent research institute in Waterloo, Ontario, Canada, founded in 1999 with a $100 million gift from BlackBerry co-founder Mike Lazaridis.