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Allende meteorite
The Allende meteorite, a carbonaceous chondrite (CV3), fell near Pueblito de Allende, Chihuahua, Mexico, in 1969; its calcium-aluminum-rich inclusions are the Solar System's oldest dated solids.
Allene
Allene (propadiene, 1,2-propadiene, CH₂=C=CH₂) is the simplest cumulated diene, a hydrocarbon whose two double bonds share one carbon and lie in perpendicular planes, first synthesized in 1887 and used in organic synthesis and MAPP fuel gas.
Allene oxide cyclase
Allene oxide cyclase (AOC, EC 5.3.99.6) is a trimeric plant lipocalin enzyme that stereospecifically cyclizes the allene oxide 12,13-EOT to cis(+)-12-oxo-phytodienoic acid, the committed precursor of jasmonic acid.
Allentown-Bethlehem-Easton, PA-NJ Metro Area
The Allentown-Bethlehem-Easton, PA-NJ Metropolitan Statistical Area (code 10900), also called the Lehigh Valley, covers Carbon, Lehigh, Northampton, and Warren counties; about 887,600 residents in 2025, Pennsylvania's third-largest metro.
Allentown, Pennsylvania
Allentown, Pennsylvania: third-largest city in the state, county seat of Lehigh County, founded 1762 by William Allen. Majority-Latino city on the Lehigh River anchoring the Allentown-Bethlehem-Easton metro.
Allergan
Allergan plc, Irish pharmaceutical maker of Botox, Juvéderm, and Restasis, acquired by AbbVie on May 8, 2020 for $63 billion; its aesthetics business continues as Allergan Aesthetics, an AbbVie company.
Allergen
Allergen: a foreign substance, usually a protein, triggering allergic reactions; term coined by Clemens von Pirquet in 1906; IgE-mediated sensitization and elicitation; WHO/IUIS nomenclature; FDA major food allergens.
Allergen immunotherapy
Allergen immunotherapy treats allergy by giving gradually increasing doses of pollen, dust mite, or venom, modifying the immune response; a course lasts 3 to 5 years.
Allergic bronchopulmonary aspergillosis
Allergic bronchopulmonary aspergillosis (ABPA) is an allergic lung disease in which the immune system reacts to Aspergillus fumigatus colonizing the airways, most often in people with asthma or cystic fibrosis.
Allergic conjunctivitis
Allergic conjunctivitis, also called ocular allergy (SAC, PAC, VKC, AKC, GPC), is IgE-mediated mast-cell inflammation of the conjunctiva causing itchy, watery, red eyes; treated stepwise with avoidance, dual-action antihistamine drops, and immunotherapy.
Allergic contact blepharoconjunctivitis
Allergic contact blepharoconjunctivitis, also called contact blepharoconjunctivitis, is a delayed hypersensitivity reaction of the eyelid skin and conjunctiva, typically triggered by cosmetics, metals, or eye drops.
Allergic contact dermatitis
Allergic contact dermatitis (ACD, contact allergy) is a type IV delayed T-cell-mediated eczema appearing 24–72 hours after skin contact with an allergen such as nickel; diagnosed by patch testing, affecting about 20% of the population.
Allergic contact dermatitis due to topical medicaments
Allergic contact dermatitis due to topical medicaments (medicament contact allergy) is type IV hypersensitivity to topical antibiotic, corticosteroid, anesthetic, or vehicle ingredients, led by bacitracin and neomycin, diagnosed by patch testing.
Allergic contact urticaria
Allergic (immunologic) contact urticaria, ICD-11 EK10, is an IgE-mediated immediate wheal-and-flare reaction after skin contact with proteins or haptens such as latex and foods, potentially spreading to anaphylaxis; diagnosed by prick testing and specific IgE, treated by avoidance.
Allergic gingivitis
Allergic gingivitis (アレルギー性歯肉炎), ICD-11 DA0B.0, is gum inflammation from hypersensitivity to dental materials, toothpaste flavorings, or foods; diagnosed by patch testing and confirmed by resolution after allergen removal.
Allergic rhinitis
Allergic rhinitis (hay fever) is an IgE-mediated nasal inflammation from inhaled allergens, affecting about 400 million people, often with asthma; treated with intranasal corticosteroids, antihistamines, saline, and allergen immunotherapy.
Allergic rhinitis due to house dust mite
Allergic rhinitis due to house dust mite (ICD-11 CA08.02): perennial IgE-mediated nasal allergy to Dermatophagoides mite fecal allergens such as Der p 1, affecting 65–130 million people, treated with pharmacotherapy and sublingual immunotherapy.
Allergic rhinitis due to pollen
Allergic rhinitis due to pollen, or hay fever, is an IgE-mediated seasonal nasal allergy to tree, grass, and ragweed pollen. Distinguished from perennial rhinitis by seasonality; treated with intranasal corticosteroids, antihistamines, and immunotherapy.
Allergy
Allergy: immunologically initiated hypersensitivity, mainly IgE-mediated type I reactions. Covers Gell–Coombs types, mast-cell degranulation, allergens, diagnosis, immunotherapy, and omalizumab's 2024 approval for food allergy.
Allergy to cats
Allergy to cats, or cat dander allergy, is an IgE-mediated reaction mainly to the Fel d 1 protein from cat saliva and skin glands; managed by avoidance, HEPA filtration, medications, and allergen immunotherapy.
Allerton Park
Allerton Park names two historic landscapes: a 205-ha grade II registered park around Allerton Castle near Knaresborough, North Yorkshire, and Allerton Park & Retreat Center, Robert Allerton's 1,500-acre Illinois estate given to the University of Illinois in 1946.
Allethrin
Allethrin is a synthetic pyrethroid insecticide, first synthesized in 1949 as an analog of natural pyrethrins, used mainly in household products such as mosquito coils.
Alleviant Medical
Alleviant Medical is a privately held medical device company in Austin, Texas, founded in 2017, developing a catheter-delivered, no-implant interatrial shunt that relieves left atrial pressure in heart failure patients; its device remains investigational.
Alley Family
The Alley family is an American family of English origin, with unrelated lines including Texas pioneers among Austin's Old Three Hundred and Congressman John Bassett Alley of Massachusetts.
Alley Mills
Alley Mills (born 1951, Chicago) is an American actress known as Norma Arnold on The Wonder Years (1988–1993), Pamela Douglas on The Bold and the Beautiful, and Emmy-winning Heather Webber on General Hospital; widow of Orson Bean.
Alleycorp Partners
AlleyCorp Partners is a New York venture capital firm founded by Kevin Ryan, which opened his 2007 family office AlleyCorp to outside investors, raising $250 million in 2024.
Alleyn's School
Alleyn's School: co-educational independent day school in Dulwich, London, ages 4-18, founded from Edward Alleyn's 1619 College of God's Gift; separate since 1882, co-ed since 1976, HMC member, head Jane Lunnon.
Alleyway (video game)
Alleyway (アレイウエイ) is Nintendo's 1989 Game Boy launch block-breaker by R&D1, a Breakout-style paddle game with 32 stages, moving and descending block walls, bonus stages, and Mario as the paddle ship's pilot; later on 3DS Virtual Console and Switch Online.
Allflex (Allflex USA / Allflex Holdings)
Allflex, also known as Allflex Livestock Intelligence, is a livestock identification manufacturer of visual and RFID ear tags, tissue sampling units, and herd monitoring products, part of Merck Animal Health since 2019.
Allgäu
Allgäu: a region in southern Bavaria and neighboring Austria, part of Swabia, known for dairy-farming meadows, the Allgäu Alps, Alemannic-Swabian dialects, and a large tourism economy.