All articles starting with U
6,146 articles
Ulli Eicke
Ulli Eicke (Ulrich Eicke, born 1952, Wuppertal) is a West German sprint canoeist, 1984 Los Angeles Olympic gold medalist in C-1 1,000 m, three-time world silver medalist, later Olympic training center head and dragon boat promoter.
Ullmann condensation
The Ullmann condensation is a copper-catalyzed reaction in which aryl halides couple with amines, phenols, or thiols to form aryl amines, ethers, and thioethers, first reported by Fritz Ullmann in 1901.
Ullmann coupling
The Ullmann coupling is a copper-mediated organic reaction first reported by Fritz Ullmann in 1901, an early transition-metal cross-coupling that joins aryl halides to form biaryls and carbon–heteroatom bonds.
Ullmann reaction
The Ullmann reaction is the copper-mediated coupling of aryl halides to form biaryl compounds, first reported by Fritz Ullmann in 1901; modern Ullmann-type variants form C–N, C–O, and other bonds.
Ulloor S. Parameswara Iyer
Ulloor S. Parameswara Iyer (ഉള്ളൂർ എസ്. പരമേശ്വര ഐയർ; 1877–1949) was a Malayalam poet, literary historian, and senior Travancore administrator, one of the Kavitrayam triumvirate of modern Malayalam poetry.
Ullozhukku (ഉള്ളൊഴുക്ക്)
Ullozhukku (ഉള്ളൊഴുക്ക്, Undercurrent) is a 2024 Malayalam drama, Christo Tomy's debut feature, starring Urvashi and Parvathy Thiruvothu as a mother-in-law and daughter-in-law in flood-stricken Kuttanad; it won the 2025 National Film Award for Best Malayalam Film.
Ullr
Ullr (Ull, Ullinn, Saxo's Ollerus) is the Norse god of archery, skiing, hunting, winter, single combat, and oaths, son of Sif and stepson of Thor, dwelling in Ýdalir. Literary sources are sparse, but place names show a major cult in central Sweden and southern Norway, absent in Denmark, declining after the seventh century.
Ullrich congenital muscular dystrophy
Ullrich congenital muscular dystrophy (UCMD, Ullrich scleroatonic muscular dystrophy, OMIM 254090): severe collagen VI-related congenital muscular dystrophy from COL6A1/COL6A2/COL6A3 mutations, with proximal contractures, distal hyperlaxity, loss of ambulation and respiratory failure by about age 11.
Ullrich Dießner
Ullrich Dießner, East German (GDR) rower born 1954 in Meißen, twin brother of Walter Dießner; Olympic silver 1976 and gold 1980 in the men's coxed four, plus six world championship titles.
Ullrich Scherf
Ullrich Scherf is a polymer chemist and Senior Professor of Macromolecular Chemistry at the University of Wuppertal, known for conjugated ladder polymers like MeLPPP used in polymer LEDs.
Ullrich Steiner
Ullrich Steiner is a Swiss soft matter physicist who holds the Chair in Soft Matter Physics at the University of Fribourg and studies how polymers organize into nanometer-scale structures.
Ullswater
Ullswater, Cumbrian lake in England's Lake District National Park; second largest after Windermere at 8.9 km2, 14.5 km long, dog-leg shaped, up to 62.5 m deep, drained by the River Eamont, served by Ullswater Steamers.
Ullucus
Ullucus (ulluco, melloco, papalisa; Ullucus tuberosus Caldas), sole species of its Basellaceae genus, is an Andean tuber crop grown at 2,600–3,800 m, notable for betalain pigments absent in other Andean tubers and for Ecuador's second-most-important tuber after potato.
Ullusunu
Ullusunu, also known as Ullusunnu, was king of Mannea in western Iran from about 716 BC, ruling as a vassal of Sargon II of Assyria.
Ulm
Ulm, Baden-Württemberg city on the Danube opposite Neu-Ulm; 129,942 residents (2023), Ulmer Münster tower 161.53 m, Free Imperial City history, Science City with Universität Ulm, and ratiopharm, SETRA, Gardena.
Ulm Minster
Ulm Minster (Ulmer Münster), Gothic Lutheran church in Ulm, Germany; begun 1377, finished 1890; 161.53 m tower was the world's tallest church tower until Sagrada Família surpassed it in 2025.
Ulmaceae
Ulmaceae (elm family), Ulmaceae Mirb. 1815, a Rosales family of trees and shrubs with distichous unequal-sided leaves and samara or drupe fruits; about 7 genera, 40–60 species, split from Cannabaceae, temperate and tropical clades.
Ulmus 'New Horizon'
Ulmus 'New Horizon' (New Horizon elm) is a Dutch elm disease resistant hybrid elm cultivar bred at the University of Wisconsin and released in the 1990s.
Ulmus americana
Ulmus americana, the American elm (also white elm), is a deciduous tree of eastern North America prized for its vase-shaped crown and now endangered, largely from Dutch elm disease.
Ulmus americana 'Princeton'
Ulmus americana 'Princeton', the Princeton American elm, is a 1922 Princeton Nurseries selection of pure American elm, later found resistant to Dutch elm disease and widely planted, including on the National Mall.
Ulmus glabra 'Camperdownii'
Ulmus glabra 'Camperdownii', the Camperdown elm or weeping elm, a weeping wych elm cultivar found mid-1800s at Camperdown House, Dundee, Scotland; propagated only by grafting, small, hardy to USDA Zone 4, susceptible to Dutch elm disease.
Ulmus glabra 'Lutescens'
Ulmus glabra 'Lutescens', the Golden Elm or Golden Wych Elm, is a wych elm cultivar found near York in the early 19th century, grown for cream-yellow spring leaves turning golden in autumn, reaching 10-12 m, popular in Australia.
Ulmus minor
Ulmus minor, field elm or smooth-leaved elm (olmo), a deciduous Ulmaceae tree native from Europe to Central Asia and NW. Africa; riparian pioneer to 20 m, devastated by Dutch elm disease (Ophiostoma), IUCN Data Deficient, with two accepted subspecies.
Ulmus pumila
Ulmus pumila, the Siberian elm (also called littleleaf, dwarf, or Chinese elm), is a fast-growing, drought- and frost-hardy Asian elm, resistant to Dutch elm disease, used in breeding and windbreaks, and invasive in North America.
Ulmus rubra
Ulmus rubra Muhl., slippery elm (also red elm, gray elm, soft elm), a medium-sized deciduous North American elm of Ulmaceae, named for mucilage in its inner bark used in throat lozenges; threatened by Dutch elm disease.
Ulna
The ulna is the medial long bone of the human forearm, extending from the elbow to the wrist beside the radius, whose pivot around it produces pronation and supination.
Ulnar artery
The ulnar artery (arteria ulnaris) is the larger terminal branch of the brachial artery, supplying the medial forearm and most blood flow to the hand.
Ulnar claw
Ulnar claw, or claw hand (intrinsic-minus hand), is a deformity with MCP hyperextension and IP flexion of the ring and little fingers from ulnar nerve palsy, causing 60-80% pinch and grip strength loss; treated with splinting and tendon transfers.
Ulnar collateral ligament reconstruction
Ulnar collateral ligament reconstruction, or Tommy John surgery, replaces a torn elbow UCL with a tendon graft; first performed by Frank Jobe on pitcher Tommy John in 1974.
Ulnar nerve
Ulnar nerve (nervus ulnaris): terminal branch of the medial cord of the brachial plexus, C8–T1, supplying forearm flexors and most intrinsic hand muscles and medial 1.5 digits; compressed at cubital tunnel or Guyon canal.