All articles starting with O
9,097 articles
Optogenetic stimulation
Optogenetic stimulation uses genetically expressed, light-activated proteins, typically channelrhodopsins, to control the electrical activity of specified cells in living tissue with millisecond precision, first demonstrated by Edward S. Boyden and colleagues in 2005.
Optogenetics
Optogenetics is a technique in which genetically modified neurons are switched on or off with light, which has transformed neuroscience and partially restored vision in a blind patient.
Optomagnetic switching
Optomagnetic switching is the reversal or control of a material's magnetization using ultrashort laser pulses alone, without an applied magnetic field, pursued for faster, lower-energy magnetic memory writing.
Optomec
Optomec is a privately held American additive manufacturing company based in Albuquerque, New Mexico, whose Aerosol Jet systems print electronics and LENS printers build and repair metal parts.
Optomechanical cooling
Optomechanical cooling uses light in an optical or microwave cavity to remove vibrational energy from a mechanical resonator, reducing its thermal motion toward the quantum ground state via radiation pressure.
Optomechanical crystal resonators
An optomechanical crystal cavity (OMCC) is a nanoscale semiconductor resonator patterned as a photonic and phononic crystal that confines light and gigahertz mechanical vibrations together, enabling microwave-to-optical quantum transduction.
Optomechanical quantum sensing
Optomechanical quantum sensing measures quantities like force, acceleration, and magnetic fields by reading out a mechanical oscillator through an optical or microwave cavity, using techniques such as squeezed light to beat the standard quantum limit.
Optomechanical quantum transducer
An optomechanical quantum transducer is a device that coherently converts quantum states of light between microwave and optical frequency domains using a mechanical resonator, linking superconducting quantum processors through optical fiber.
Optometrists
Optometrists are eye care professionals holding the Doctor of Optometry (O.D.) degree who examine eyes, prescribe lenses and medications, and refer complex disease; scope of practice varies by jurisdiction.
Optometry
Optometry is the eye care profession of examining eyes, diagnosing vision problems and eye disease, and prescribing corrective lenses; practitioners are optometrists (OD degree in the US), distinct from ophthalmologists, who are physician surgeons.
Optoplasmonic single-molecule sensing
Optoplasmonic single-molecule sensing is a label-free optical detection technique in which a whispering-gallery-mode microresonator combined with a plasmonic nanoparticle registers single molecules, even single ions, as resonance shifts.
Optoretinography
Optoretinography (ORG) is a dye-free optical imaging method that measures how photoreceptors in the living retina respond to light, detecting dysfunction in diseases such as retinitis pigmentosa.
Optum
Optum is UnitedHealth Group's health services arm, founded April 2011 in Eden Prairie, Minnesota, with segments Optum Health, Optum Insight, and Optum Rx; it employs about 300,000 people and is a major PBM and physician employer.
Optus
Optus, formally Singtel Optus Pty Limited, is an Australian telecommunications company offering mobile, broadband, satellite, and subscription television services, wholly owned by Singtel since 2001.
Opuntia
Opuntia (prickly pear, cactus pear) is a genus of about 150 American cacti with jointed cladodes, glochids, and edible fruits, used for food, forage, and cochineal dye, and invasive in many regions.
Opuntia decumbens
Opuntia decumbens Salm-Dyck is a prickly pear cactus in the family Cactaceae, native from Mexico to Central America, first published in 1834 in the Hortus Dyckensis.
Opuntia ficus-indica
Opuntia ficus-indica (prickly pear, cactus pear, nopal, Indian fig opuntia) is a Mexican-domesticated CAM cactus grown for fruit, nopalitos, and forage; cladodes are 88-95% water, WUE 3-5x C3/C4 crops, up to 50 t dry mass/ha/yr.
Opuntia leucotricha
Opuntia leucotricha, called nopal duraznillo in Spanish and Aaron's-beard prickly-pear in English, is a prickly pear cactus from the Altiplano of central Mexico that grows 3 to 4 m tall with white hair-like spines.
Opus
Opus is a creative work, generally a musical composition, used since Tinctoris (c. 1430–1511). Originally assigned by 17th-century publishers, the numbering often fails to reflect chronological order.
Opus (audio format)
Opus is a royalty-free, lossy audio codec standardized by the IETF as RFC 6716 in 2012, combining Skype's SILK and Xiph.Org's CELT for speech and music.
Opus (film)
Opus is a 2025 American horror-thriller film directed by Mark Anthony Green, starring Ayo Edebiri as a music journalist lured to a pop star's compound.
Opus Anglicanum
Opus Anglicanum, Latin for "English work," is the luxurious embroidery made in England from about the 12th to the early 16th centuries, prized across medieval Europe.
Opus Dei
Opus Dei, formally the Personal prelature of Opus Dei, is a Catholic institution founded by St. Josemaría Escrivá in Madrid in 1928, the Church's only personal prelature.
Opus Eponymous
Opus Eponymous is the 2010 debut studio album by Swedish band Ghost, released on Rise Above Records. Recorded in Linköping by Tobias Forge (as producer pseudonym Gene Walker), it pairs Satanic occult imagery with melodic 1970s-style heavy metal and became Rise Above's biggest seller.
Opus III
Opus III were a British rave and dance group whose 1992 single "It's a Fine Day", fronted by vocalist Kirsty Hawkshaw, reached number 5 in the UK.
Opus Kink
Opus Kink: Brighton, England jazz-punk six-piece formed 2017 (Angus Rogers, Sam and Fin Abbo, Jazz Pope, Jed Morgans, Jack Banjo Courtney). Debut album The Sweet Goodbye, 31 July 2026, SO Recordings; runs Hideous Mink Records.
Opus number
Opus number (Op., plural Opp.): Latin "work"; number identifying a composition or set, usually by publication order. Unreliable chronology; replaced by thematic catalogs like Köchel (Mozart), Hoboken (Haydn), BWV (Bach), Deutsch (Schubert), and WoO for unnumbered works.
OR gate
The OR gate, or OR circuit, is a digital logic circuit whose output is HIGH when at least one input is HIGH, implementing inclusive logical disjunction.
Or Gozani
Or Gozani is a molecular biologist and the Dr. Morris Herzstein Professor of Biology at Stanford University, where his laboratory has studied histone methylation in cancer since 2005.
OR Tambo District Municipality
OR Tambo District Municipality (DC15) is an Eastern Cape district municipality, seat Mthatha, named after Oliver Tambo, with five local municipalities, 1,364,943 mostly Xhosa-speaking people, and a water and sanitation mandate.