All articles starting with H
20,046 articles
Hypertrophy of nasal turbinates
Hypertrophy of nasal turbinates (turbinate hypertrophy, ICD-10 J34.3, ICD-11 CA0E) is enlargement of the nasal turbinates, usually the inferior, from allergic or vasomotor rhinitis, causing nasal obstruction; treated with steroids and saline first, surgery if refractory.
Hypertrophy of salivary gland
Hypertrophy of salivary gland (salivary gland enlargement, hyperplasia; ICD-11 DA04.1, ICD-10 K11.1) is enlargement of salivary glands, chiefly the non-inflammatory sialadenosis with acinar hypertrophy, linked to diabetes, alcoholism, malnutrition, medications, and stones.
Hypertrophy of tonsils
Hypertrophy of tonsils (tonsillar hypertrophy, enlarged tonsils; ICD-11 CA0F.0) is persistent enlargement of the palatine tonsils, common in children ages 3–7, causing mouth breathing and snoring; about 8 of 10 children with OSA have enlarged tonsils, and tonsillectomy resolves OSA in 82%.
Hypertrophy of vulva
Hypertrophy of vulva (外陰肥大, ICD-11 GA13.2; ICD-10 N90.6) is enlargement or thickening of external female genital tissues, often idiopathic; includes labial and clitoral hypertrophy, treated by labiaplasty when symptomatic.
Hypertryptophanemia
Hypertryptophanemia, also called familial hypertryptophanemia (OMIM 600627), is a rare autosomal recessive inborn error of tryptophan metabolism caused by TDO2 deficiency, producing congenital hypertryptophanemia, hyperserotonemia, and tryptophanuria, usually without symptoms.
Hyperuniform states of active matter
Hyperuniform states of active matter are nonequilibrium assemblies of self-driven agents in which large-scale density fluctuations are suppressed to crystal-like levels, seen in circle swimmers, algae, and active field theories.
Hyperuricemia
Hyperuricemia is abnormally high blood uric acid (serum urate above 6.8 mg/dL), caused by overproduction or underexcretion of urate after humans lost uricase. It causes gout and kidney stones; treated with allopurinol, febuxostat, uricosurics, or uricases.
Hyperuricemia-pulmonary hypertension-renal failure-alkalosis syndrome
HUPRA syndrome (hyperuricemia-pulmonary hypertension-renal failure-alkalosis syndrome), also called HUPRAS, is an ultra-rare autosomal recessive mitochondrial disease caused by SARS2 mutations, presenting in infancy with renal failure, metabolic alkalosis, and pulmonary hypertension.
Hypervalent iodine chemistry
Hypervalent iodine chemistry is the branch of chemistry dealing with iodine compounds in +3 and +5 oxidation states, used as selective, metal-free oxidants that resemble transition metals.
Hypervalent iodine(III) reagents
Hypervalent iodine(III) reagents, the λ3-iodanes, are trivalent iodine compounds acting as powerful electrophilic oxidants and group-transfer reagents in organic synthesis, including PIDA, iodonium salts, and benziodoxoles used in C–H activation.
Hypervalent organotellurium compounds
Hypervalent organotellurium compounds are organotellurium molecules in which tellurium formally exceeds the octet rule; they include σ-telluranes, telluroxanes, and cyclic telluranes, and are more thermally stable than sulfur or selenium analogs.
Hypervelocity stars
Hypervelocity stars are stars fast enough to escape the Milky Way's gravity entirely, exceeding Galactic escape velocity; the term was coined in 1988 and the first was found in 2005.
Hyperventilation
Hyperventilation (overbreathing) is ventilation exceeding metabolic needs, lowering PaCO2 and causing respiratory alkalosis; chronic symptomatic forms are called hyperventilation syndrome, linked to anxiety and asthma.
Hypervigilance
Hypervigilance: a heightened, continuous scanning of the environment for danger, a symptom rather than a diagnosis. Seen in PTSD, anxiety, trauma, and physical conditions; distinct from paranoia, managed with therapy, grounding, and mindfulness.
Hypervisor
A hypervisor, or virtual machine monitor, is a software layer between hardware and operating systems that runs multiple isolated virtual machines and arbitrates access to hardware.
Hypervitaminosis
Hypervitaminosis: vitamin toxicity, chiefly of fat-soluble vitamins A and D, from excess supplements or retinoid drugs; includes hypervitaminosis A and hypervitaminosis D with hypercalcemia.
Hypervitaminosis A
Hypervitaminosis A, or vitamin A toxicity, is poisoning from excess preformed retinol, causing acute headache and raised intracranial pressure or chronic liver, bone, and hypercalcemia effects, mainly from supplement misuse.
Hypervolemia
Hypervolemia, or fluid overload, is excess body fluid or blood volume, caused by excess sodium, heart or kidney disease, cirrhosis, or pregnancy; treated with diuretics, salt and fluid restriction, and dialysis.
Hypervolume indicator
The hypervolume indicator, also called the S-metric or Lebesgue measure, is a quality measure for solution sets in multi-objective optimization, introduced by Zitzler and Thiele in 1998.
Hyperwise Ventures
Hyperwise Ventures is a venture capital firm in Tel Aviv, Israel, founded in 2020, describing itself as a lead seed investor in cybersecurity and enterprise software.
HyperX
HyperX is a gaming hardware brand owned by HP Inc. that makes headsets, keyboards, mice, and microphones; Kingston founded it in 2002, and HP bought it in 2021.
Hyperzincemia and hypercalprotectinemia
Hyperzincemia and hypercalprotectinemia (Hz/Hc, AICZC, PAMI syndrome) is a rare PSTPIP1 (E250K, E257K) autoinflammatory disorder with high blood zinc and calprotectin, cytopenia, hepatosplenomegaly, and skin and joint inflammation.
Hypha
Hypha (plural hyphae): the tubular filament that is the structural unit of fungi, growing by apical tip growth via the Spitzenkörper, branching to form mycelium; distinct from pseudohyphae and yeast forms.
Hyphaene
Hyphaene (doum palms), genus of dioecious coryphoid palms native from tropical and southern Africa to Sri Lanka, unique for dichotomously branching trunks; about 8 species, edible fruits, Eocene origin, difficult taxonomy with many synonyms.
Hyphaene thebaica
Hyphaene thebaica, the doum or gingerbread palm (دوم), is a branching dioecious African palm from West Africa to Arabia, with hard edible fruits rich in fiber, potassium, and phenolics, sacred in ancient Egypt.
Hyphal cell
Hyphal cell: a cell of a fungal hypha, the filament of a mycelium. Grows by apical tip growth via the Spitzenkörper, is compartmentalized by septal pores and Woronin body plugs, and underlies fungal multicellularity and dimorphism.
Hyphanet
Hyphanet, the original Freenet project since 1999, is a peer-to-peer network for censorship-resistant, anonymous publishing and communication, storing encrypted file pieces across participants' computers and retrieving content by cryptographic key.
Hyphema
Hyphema is blood in the eye's anterior chamber, usually from blunt trauma; graded 0–IV (microhyphema to eight-ball), complicated by rebleeding, raised intraocular pressure, and corneal blood staining.
Hyphen
The hyphen (-) joins words into compounds, attaches some prefixes, and marks line-break word division; distinct from the en dash (–) and em dash (—), with usage drifting from hyphenated to closed forms.
Hyphy
Hyphy: high-energy Bay Area hip-hop movement from Oakland and Vallejo, coined by Keak Da Sneak, driven by E-40, Mac Dre, thizz culture, ghostriding, and sideshows, peaking nationally in 2006.