All articles starting with O
9,097 articles
Oxygen precipitation
Oxygen precipitation is the formation of silicon dioxide particles from dissolved oxygen in Czochralski-grown silicon wafers during annealing, the basis of intrinsic gettering that traps metallic contaminants away from devices.
Oxygen radical absorbance capacity
Oxygen radical absorbance capacity (ORAC) is a chemical assay measuring antioxidant capacity of foods and biological samples in Trolox equivalents; the USDA removed its ORAC database in 2012.
Oxygen redox instability in Li-rich cathodes
Oxygen redox instability in Li-rich cathodes is the tendency of lithium-rich layered oxide battery cathodes to lose capacity and voltage because oxidized lattice oxygen escapes as O₂.
Oxygen reduction reaction
The oxygen reduction reaction (ORR) is the critical cathode reaction in fuel cells and metal-air batteries. It is known for its kinetic sluggishness and reliance on expensive platinum group catalysts.
Oxygen saturation
Oxygen saturation (SaO2) is the percentage of hemoglobin binding sites in blood occupied by oxygen, normally 96 to 98%, and routinely estimated non-invasively by pulse oximetry.
Oxygen saturation (medicine)
Oxygen saturation (SaO2/SpO2) is the percentage of hemoglobin carrying oxygen, measured non-invasively by pulse oximetry, invented by Takuo Aoyagi in 1972; normal 95-100%, with known accuracy limits from skin pigmentation.
Oxygen sensor
An oxygen sensor, also called an O2 sensor or lambda probe, measures the oxygen concentration in a gas or liquid and converts it into an electrical or optical signal.
Oxygen therapy
Oxygen therapy: administration of supplemental medicinal oxygen, an WHO essential medicine, via cannulas, masks, or high-flow devices; landmark NOTT and MRC trials established survival benefit of long-term oxygen in severe COPD hypoxemia.
Oxygen toxicity
Oxygen toxicity: tissue damage from breathing oxygen above physiological partial pressures. Also Paul Bert effect (CNS seizures, 1.3–1.6 atm diving limit) and Lorrain Smith effect (lung damage above 0.5 ata prolonged exposure).
Oxygen vacancies as OER active sites in perovskites
Oxygen vacancies in perovskite oxides, written ABO3-δ, are missing lattice oxygens that serve as catalytic active sites for the oxygen evolution reaction in water electrolysis and metal-air batteries.
Oxygen-18
Oxygen-18, a stable isotope making up about 0.205 percent of natural oxygen, serves as a paleoclimate tracer in ice cores and as enriched water feedstock for producing fluorine-18 in PET imaging.
Oxygen-depolarized cathode
An oxygen-depolarized cathode (ODC) is a gas diffusion electrode in chlorine electrolysis that reduces oxygen instead of evolving hydrogen, cutting electricity demand by about 30 percent.
Oxygen-evolving complex mimics
Oxygen-evolving complex mimics are synthetic manganese-based catalysts modeled on photosystem II's Mn4CaO5 cluster, designed to study water oxidation and build efficient catalysts for artificial photosynthesis.
Oxygen–hemoglobin dissociation curve
Oxygen–hemoglobin dissociation curve (oxyhemoglobin dissociation curve, ODC): sigmoid plot of hemoglobin oxygen saturation versus oxygen partial pressure; P50 about 26 mmHg for adult blood, shifted right by low pH, high CO2, heat, and 2,3-DPG, left by fetal hemoglobin and carbon monoxide.
Oxygenators
Oxygenators, also called artificial lungs or membrane oxygenators, are blood-gas exchangers used in cardiopulmonary bypass and ECMO; modern designs use polypropylene hollow fiber membranes for oxygen and carbon dioxide exchange.
Oxygène
Oxygène, Jean-Michel Jarre's third studio album, is a six-part instrumental electronic work recorded in his Paris apartment kitchen in 1976 on an eight-track machine, released on Disques Motors; "Oxygène (Part IV)" hit number 1 in France, and the album sold roughly 12-18 million copies.
OxygenOS
OxygenOS is an Android-based operating system developed by OnePlus for its smartphones and tablets, known for a fast, stock-like design; in 2026 OnePlus began phasing it out in favor of Oppo's ColorOS.
Oxyhydrogen
Oxyhydrogen, also known as knallgas or Brown's gas, is a 2:1 mixture of hydrogen and oxygen that burns with a very hot flame back to water.
Oxyl–oxo coupling mechanism in photosystem II
The oxyl–oxo coupling mechanism is a proposed route for the oxygen–oxygen bond-forming step of water oxidation in photosystem II, proposed by Per Siegbahn in 2006 using density functional theory.
Oxylipin
An oxylipin is an oxygenated, bioactive lipid mediator formed from polyunsaturated fatty acids by enzymatic or non-enzymatic oxidation, regulating inflammation in animals and stress responses in plants.
Oxymatrine
Oxymatrine (matrine N-oxide, Ammothamnine), a quinolizidine alkaloid from Sophora flavescens roots, studied for anticancer, antiviral, anti-inflammatory, and antifibrotic effects; not approved as an EU pesticide active substance.
Oxymetazoline
Oxymetazoline (Afrin, Rhofade) is an imidazoline alpha-adrenergic agonist vasoconstrictor used as a 0.05% OTC nasal decongestant spray and as 1% cream for rosacea erythema; overuse risks rebound congestion.
Oxymetholone
Oxymetholone (Anadrol-50) is a 17α-alkylated anabolic-androgenic steroid, a synthetic testosterone derivative once FDA-approved for anemias from deficient red cell production; now discontinued in the US, hepatotoxic, and listed as reasonably anticipated to be a human carcinogen.
Oxymoron
Oxymoron: a figure of speech pairing contradictory words for effect, such as jumbo shrimp, deafening silence, or cruel kindness. From Greek oxys (sharp) plus moros (foolish); first used in English in 1656; distinct from paradox.
Oxymorphone
Oxymorphone (14-hydroxydihydromorphinone), brand Opana/Opana ER, is a semisynthetic Schedule II mu-opioid agonist painkiller; injectable form approved 1959, oral IR/ER 2006, reformulated ER withdrawn 2017 after abuse shifted to injection.
Oxymycterus
Oxymycterus, the hocicudos, is a South American sigmodontine rodent genus (Akodontini) named by Waterhouse in 1837 from Darwin's collection; long-nosed, burrowing mice including O. nasutus, O. rufus, and O. wayku.
Oxynoticeras
Oxynoticeras, extinct Early Jurassic ammonite genus (family Oxynoticeratidae) from Europe and North America; smooth keeled shells, type species O. oxynotum, possible macroconch of Cheltonia.
Oxyntas
Oxyntas was a Numidian prince, son of King Jugurtha, paraded in Marius' triumph in 104 BC and used as a figurehead by Samnite rebels in 90 BC.
Oxyopes
Oxyopes (grass lynx spiders) is the largest genus of lynx spiders, family Oxyopidae, established by Latreille in 1804 with type species O. heterophthalmus; about 285 species of spiny-legged, diurnal plant-hunting spiders, including the biocontrol agent O. salticus.
Oxypertine
Oxypertine (WIN 18,501-2, Integrin) is a phenylpiperazine antipsychotic introduced in the 1960s for schizophrenia; a dopamine antagonist and monoamine depleter, now used predominantly in Japan.