All articles starting with O

Oxalate

Oxalate, also called ethanedioate or the oxalate ion, is the dianion of oxalic acid, best known as the main component of most human kidney stones.

Oxalic acid

Oxalic acid (ethanedioic acid, C2H2O4) is the simplest dicarboxylic acid, a colorless crystalline solid that occurs widely in plants as calcium oxalate and can damage the kidneys in high doses.

Oxalidaceae, the wood sorrel family (Oxalidales), is a nearly cosmopolitan flowering-plant family of 5 genera, Averrhoa, Biophytum, Dapania, Oxalis, and Sarcotheca, and roughly 570-800 species, including star fruit, bilimbi, and oca.

Oct 20, 2026

Oxalidales

Oxalidales (Bercht. & J.Presl 1820) is a rosid order of flowering plants in the COM clade, containing Oxalidaceae, Connaraceae, Brunelliaceae, Cephalotaceae, Cunoniaceae, and Elaeocarpaceae, with Huaceae now excluded by phylogenomic work.

Oxaliplatin

Oxaliplatin, sold as Eloxatin, is a platinum-based chemotherapy drug approved in the United States in 2002 for colorectal cancer, used with 5-fluorouracil and leucovorin; its dose-limiting toxicity is peripheral neuropathy.

Oxalis

Oxalis, commonly known as wood sorrel, is a large genus of flowering plants with clover-like leaves, five-petaled flowers twisted in the bud, and tissues rich in oxalic acid.

Oxalis acetosella

Oxalis acetosella, wood sorrel (Wald-Sauerklee, Alléluia), a small perennial Oxalidaceae herb of shady Eurasian woods, with white purple-veined flowers, sour oxalic-acid leaves, and a Europe-to-Japan native range.

Oxalis triangularis

Oxalis triangularis (purple shamrock, false shamrock; synonym Oxalis regnellii) is a tuberous South American wood sorrel grown as a houseplant, with triangular purple leaves that fold at night via nyctinastic pulvinus movement and tart edible foliage.

Oxaloacetic acid

Oxaloacetic acid, also called oxaloacetate or OAA, is a four-carbon dicarboxylic acid that starts and ends the citric acid cycle and is the first committed intermediate of gluconeogenesis.

Oxamate carbamoyltransferase subunit AllF

AllF (Q47208, formerly fdrA) is an E. coli K12 protein that with AllG and AllH forms oxamate carbamoyltransferase (EC 2.1.3.5), splitting oxalurate into oxamate and carbamoyl phosphate during anaerobic allantoin degradation.

Oxamniquine

Oxamniquine (ATC P02BA02) is a prodrug antischistosomal drug active only against Schistosoma mansoni; activated by a schistosome sulfotransferase, it gives 80–90% cure rates, was superseded by praziquantel, and remains a WHO complementary essential medicine for praziquantel failures.

Oxamyl

Oxamyl is a highly toxic N-methyl carbamate pesticide used as an insecticide, miticide, nematicide, and plant growth regulator on field crops, vegetables, fruits, and ornamentals.

Oxana Fedorova (Оксана Фёдорова)

Oxana Fedorova (Оксана Фёдорова, legal name Borodina), born 1977 in Pskov, Russian TV presenter and former police officer; Miss Universe 2002, first Russian winner, relinquished the title after 119 days to Justine Pasek; Honored Artist of Russia 2024.

Oxana Malaya

Oxana Malaya, born 1983 in Novaya Blagoveschenka, Ukraine, is a feral-child case found in 1991 at age eight after reportedly living five years in a dog kennel; later assessed by psychologist Lyn Fry and living in care near Odesa.

Oxandrolone

Oxandrolone (Oxandrin) is a synthetic 17-alpha-alkylated anabolic steroid, formerly FDA-approved for weight gain and corticosteroid catabolism; approval withdrawn June 2023. Best studied in burns: faster recovery, no mortality benefit, hepatotoxicity risk.

Oxane Materials

Oxane Materials Inc was a Houston, Texas company founded in 2002 to make nanotechnology-enhanced ceramic proppants for hydraulic fracturing; it filed for bankruptcy in 2015.

Oxanorbornadiene

Oxanorbornadiene (7-oxabicyclo[2.2.1]hepta-2,5-diene) is a strained bicyclic organic compound made by Diels-Alder reaction of furan with an alkyne; its dicarboxylate derivatives serve as cleavable, electrophilic linkers in bioconjugation and drug delivery.

Oxapampa-Ashaninka-Yanesha Biosphere Reserve

Oxapampa-Ashaninka-Yanesha Biosphere Reserve (BIOAY), a UNESCO MAB reserve designated 2 June 2010 in Pasco, central Peru, covering 1,774,090 ha of Tropical Yungas with Yanachaga-Chemillén National Park and three other protected areas.

Oxaprozin

Oxaprozin (DAYPRO, COXANTO) is a long-half-life propionic acid NSAID inhibiting COX-1/COX-2, indicated for osteoarthritis, rheumatoid arthritis, and juvenile rheumatoid arthritis at 1,200 mg once daily, maximum 1,800 mg or 26 mg/kg daily.

Oxasulfuron

Oxasulfuron (CGA 277476), a sulfonylurea ALS-inhibitor herbicide for broadleaf weed control in soybean; EU approval not renewed by Regulation 2018/1019 after EFSA peer review found neurotoxicity and data gaps.

Oxathiapiprolin

Oxathiapiprolin (Zorvec) is a DuPont-discovered piperidinyl thiazole isoxazoline fungicide, FRAC code 49, inhibiting oomycete oxysterol binding proteins; used against late blight, downy mildews, and pink rot, with FRAC mixture and rotation limits.

Oxazepam

Oxazepam (Serax) is a short-acting benzodiazepine for anxiety, insomnia, and alcohol withdrawal, marketed since 1965. It is glucuronidated directly with no active metabolites, preferred in liver disease and the elderly, and a US Schedule IV drug.

Oxazole

Oxazole (C₃H₃NO) is a five-membered aromatic heterocycle containing one oxygen and one nitrogen atom separated by a carbon, common in pharmaceuticals and marine natural products.

Oxazolidine

Oxazolidine is a saturated five-membered heterocyclic compound with one oxygen and one nitrogen atom, made by condensing 1,2-amino alcohols with aldehydes or ketones, and used as chiral auxiliaries in asymmetric synthesis.

Oxazolidinone

An oxazolidinone is a five-membered cyclic carbamate important in asymmetric synthesis as the Evans chiral auxiliary and as the core of antibiotics such as linezolid, approved in 2000.

Oxazolone

Oxazolone (4-ethoxymethylene-2-phenyl-5(4H)-oxazolone) is a heterocyclic compound of the azlactone family, classified as an immunologic adjuvant and sensitizing agent used to induce contact hypersensitivity and colitis models in mice.

Oxbotica

Oxbotica was a British autonomous vehicle software company founded in Oxford in 2014 as a University of Oxford spin-out, rebranded as Oxa in 2023 to focus on industrial self-driving software.

Oxbow lake

Oxbow lake: crescent-shaped lake on a floodplain formed when a meandering river cuts off a loop; fills with sediment over centuries, leaving a clay plug.

Oxbridge

Oxbridge is the collective term for Oxford and Cambridge, Britain's oldest universities, known for their autonomous colleges, tutorial-based teaching, October UCAS deadline, and one-university-per-cycle application rule.