All articles starting with P
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Peripheral neuropathy
Peripheral neuropathy is damage to peripheral nerves causing numbness, pain, weakness, or autonomic dysfunction; over 100 types exist. Diabetes is the leading cause, affecting up to 50% of long-term diabetics; monofilament screening sensitivity ranges 41-93%.
Peripheral park area
Peripheral park area (GEMET concept 10214; German Parkrandgebiet) is a park zone where scientific research is allowed, lying inside an outer buffer zone that shields the reserve from agricultural, industrial and urban development.
Peripheral primitive neuroectodermal tumor
Peripheral primitive neuroectodermal tumor (pPNET, PPNET, ICD-O 9364) is a rare aggressive small round cell sarcoma of bone or soft tissue outside the CNS, part of the Ewing family of tumors with the t(11;22) EWS-FLI1 fusion, peaking in the second decade.
Peripheral pulmonary stenosis
Peripheral pulmonary stenosis (branch pulmonary artery stenosis, PPAS) is narrowing of peripheral pulmonary artery branches, congenital or acquired, linked to Williams and Alagille syndromes; treated by balloon angioplasty, stenting, or surgery.
Peripheral quantitative computed tomography
Peripheral quantitative computed tomography (pQCT) is a low-dose CT technique measuring volumetric bone density and geometry at peripheral sites like the radius and tibia, separating cortical from trabecular bone.
Peripheral retinal degeneration
Peripheral retinal degeneration is a group of acquired or congenital retinal lesions outside the macula in which tissue thins, splits, or atrophies, sometimes leading to rhegmatogenous retinal detachment.
Peripheral spondyloarthritis
Peripheral spondyloarthritis (pSpA) is the peripheral-joint form of spondyloarthritis, marked by arthritis, enthesitis, and dactylitis, classified by 2011 ASAS criteria and distinguished from axial SpA and psoriatic arthritis sine psoriase.
Peripheral T-cell lymphoma not otherwise specified
Peripheral T-cell lymphoma not otherwise specified (PTCL-NOS) is the most frequent nodal mature T-cell lymphoma, diagnosed by exclusion, with TBX21 and GATA3 molecular subgroups and poor CHOP outcomes.
Peripheral venous malformations
Peripheral venous malformations: common congenital slow-flow vascular malformations of abnormal veins, formerly called cavernous hemangioma, driven by TEK/TIE2 or PIK3CA mutations, treated mainly by sclerotherapy.
Peripheral vision
Peripheral vision is sight outside the fovea, covering about 99.9% of the visual field. Also called indirect or eccentric vision, it is limited mainly by crowding, not blur, and excels at motion and scene gist.
Peripherally inserted central catheter
Peripherally inserted central catheter (PICC): central venous catheter inserted via an arm vein with tip in the lower SVC or cavoatrial junction; first described 1975, used for antibiotics, nutrition, chemotherapy; key risks are bloodstream infection and thrombosis.
Periphery (band)
Periphery is an American progressive metal band formed in 2005 in Washington, D.C., by Misha Mansoor from his Bulb project, known for djent-style guitar work, albums Periphery through A Pale White Dot, and the 3DOT Recordings label.
Periphery countries
Periphery countries, also known as peripheral countries or the global periphery, are the structurally disadvantaged states in world-systems theory, from which wealth flows to core countries.
Periphyton
Periphyton (Aufwuchs): attached community of algae, bacteria, fungi, protozoa, and detritus on submerged surfaces in aquatic ecosystems; key in primary productivity, nutrient cycling, bioassessment, and water purification.
Periplasmic binding protein
Periplasmic binding proteins (PBPs, solute-binding proteins) are two-domain bacterial periplasmic receptors that bind sugars, amino acids, ions, and peptides with high affinity, closing around ligands to drive ABC and TRAP transport, chemotaxis, biosensor engineering, and eukaryotic receptor domains.
Periplasmic protein thiol:disulphide oxidoreductase DsbE
DsbE, also called CcmG, is a membrane-anchored periplasmic thioredoxin-like oxidoreductase of E. coli System I, reduced by DsbD, that reduces apocytochrome c CXXCH motifs for cytochrome c maturation.
Periploca
Periploca Tourn. ex L., a genus of 17 accepted species in Apocynaceae (Periplocoideae), native from Macaronesia and the Mediterranean to tropical Africa and Asia; includes medicinal species P. sepium (Xiangjiapi) and P. forrestii (Heiguteng).
Periplus of the Erythraean Sea (Περίπλους τῆς Ἐρυθρᾶς Θαλάσσης)
Periplus of the Erythraean Sea (Periplus Maris Erythraei): anonymous Greek merchant's handbook of the mid-1st century CE describing Red Sea, Arabian, and Indian Ocean trade routes, ports, and commodities, preserved in a single Heidelberg manuscript.
Perirectal abscess
Perirectal (perianal, anorectal) abscess: pus collection near the anus, usually cryptoglandular. Treated by incision and drainage; antibiotics and packing have limited roles; fistula follows in a third to half.
Periscope
A periscope is an optical instrument that lets an observer see over an obstacle through a tube with two 45-degree mirrors, used in submarines and trenches.
Perisoreus
Perisoreus (Gray Jays) is a corvid genus with three species: Canada Jay, Siberian Jay, and Sichuan Jay, boreal resident birds that cache perishable food in saliva-coated boluses for winter survival and early breeding.
Perisphinctes
Perisphinctes (Waagen, 1869) is an Oxfordian ammonite genus with evolute, ribbed shells; type species Ammonites variocostatus; index fossil P. plicatilis; ancestor of Ataxioceratidae.
Perisplenitis
Perisplenitis, including hyaline perisplenitis (icing-sugar spleen), is inflammation of the splenic capsule and its peritoneal covering, ICD-11 3B81.A; caused by infection, infarction, portal hypertension, or pancreatitis, causing left upper quadrant pain.
Perissodactyla
Perissodactyla, commonly called the odd-toed ungulates, is an order of hoofed placental mammals named for bearing one to three weight-bearing toes, with living members the horses, rhinoceroses, and tapirs.
Peristalsis
Peristalsis: involuntary wave-like contraction and relaxation of digestive tract muscles propelling contents from pharynx to anus; includes esophageal waves, the fasting migrating motor complex, and disorders such as achalasia and gastroparesis.
Peristaltic pump
A peristaltic pump, also known as a hose pump or roller pump, is a positive displacement pump that moves fluid by rhythmically squeezing a flexible tube, so the fluid touches nothing but the tube.
Peristéri
Peristeri (Περιστέρι), municipality in West Athens, Greece, 4.5 km northwest of the city center, 10.05 km²; detached from Athens in 1934, largest West Athens municipality, three metro stations, mayor Andreas Pachatouridis since 2003.
Peristome and spore discharge in bryophytes
The peristome is the ring of teeth around a moss capsule's mouth that opens and closes with humidity to release spores; liverworts and hornworts use other mechanisms.
Peritas Investments
Peritas Investments is a New York venture capital firm whose debut fund, Peritas Investments 1, LP, filed a $100 million target offering with the SEC in May 2026.
Peritectic point
A peritectic point is the invariant point on a phase diagram where, on cooling, a liquid and a previously formed solid react isothermally to produce a new solid phase.