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Fossil sea cucumbers
Fossil sea cucumbers are the remains of holothuroids, soft-bodied echinoderms known from the Ordovician onward, over 464 million years, mostly through microscopic skeletal ossicles rather than complete body fossils.
Fossil spider deposits and preservation
The fossil record of spiders, the best documented of any arachnid order, includes about 1150 species, dominated by Baltic, Burmese, and Dominican amber and rock deposits like Crato and Aix-en-Provence.
Fossil Trochoidea and Seguenzioidea
Fossil Trochoidea and Seguenzioidea are vetigastropod gastropod superfamilies whose fossil record runs from the Devonian, about 388 Ma, to the Pleistocene, classified mainly by shell characters.
Fostamatinib
Fostamatinib (Tavalisse, Tavlesse) is an oral SYK inhibitor approved in 2018 (US) and 2020 (EU) for chronic immune thrombocytopenia in adults after prior treatment failure; stable response 18% vs 2% placebo in phase 3 FIT trials.
Fostemsavir
Fostemsavir (Rukobia, BMS-663068) is a prodrug of temsavir, the first gp120-directed HIV-1 attachment inhibitor, FDA-approved in 2020 for multidrug-resistant HIV-1 in heavily treatment-experienced adults; 600 mg twice daily.
Fosthiazate
Fosthiazate is an organophosphorus nematicide and insecticide, applied to soil at about 3 kg per hectare to control plant-parasitic nematodes in potatoes, tomatoes, and banana.
Fosthietan
Fosthietan (CAS 21548-32-3, Nem-A-Tak, Geofos) is an obsolete organophosphate soil insecticide and nematicide, a cholinesterase inhibitor, fatal if swallowed or on skin; not approved in the EU and not registered in the US.
Fosun Yaopharma oral small-molecule GLP-1 receptor agonist (licensed to Pfizer)
YP05002, Fosun Yaopharma's oral small-molecule GLP-1 receptor agonist, is an experimental once-daily pill for weight management developed by YaoPharma, a Fosun Pharma subsidiary, and licensed exclusively to Pfizer in December 2025.
Fotagliptin benzoate (SAL067)
Fotagliptin benzoate (SAL067, FCN-005; trade name Xinliting, 信立汀) is a Chinese Category 1 DPP-4 inhibitor approved by NMPA in June 2024 for adult type 2 diabetes, dosed 12 mg once daily alone or with metformin, with compound patent to 2030.
Fotemustine
Fotemustine (Muphoran, S 10036) is a chloroethylating nitrosourea alkylating agent that crosses the blood-brain barrier; used in Europe for disseminated melanoma with brain metastases, recurrent glioblastoma, and primary CNS lymphoma, but not US-approved.
Fotis C. Kafatos
Fotis C. Kafatos (1940–2017) was a Greek developmental and molecular biologist who sequenced the malaria mosquito genome, directed EMBL, and chaired the European Research Council.
Foundation (cosmetics)
Foundation, also known as fond de teint, is a flesh-toned cosmetic applied to the face to even skin tone and conceal imperfections, sold as liquids, creams, and powders.
Founder effect
Founder effect: random shift in allele frequencies when a small group founds a new isolated population, an extreme case of genetic drift. Classic examples include Ellis-van Creveld syndrome in the Old Order Amish, traced to one 18th-century immigrant couple.
Foundress behavior and colony founding in social wasps
Foundress behavior in social wasps is the spring founding of new paper nests by overwintered females, singly or in groups, with group founding improving survival.
Fouquieria fasciculata
Fouquieria fasciculata (ocotillo, árbol del barril, tzitcó) is a Vulnerable, CITES Appendix I caudex shrub of southern Hidalgo, Mexico, in subg. Bronnia with F. purpusii, bearing white ten-stamened winter flowers.
Four square step test
The four square step test (FSST) is a timed clinical test of dynamic standing balance in which the patient steps over four canes in a cross pattern.
Four Volumes of Nectar
四部甘露 (Four Volumes of Nectar, 甘露四部, 都德泽西): four 18th-century medical treatises by the Mongolian physician Ishbaljir (1704–1788), a foundational classic of Mongolian medicine integrating the Tibetan Four Tantras with cold-heat pattern diagnosis.
Four-dimensional computed tomography
Four-dimensional computed tomography is a CT acquisition and reconstruction method that resolves a scanned volume over the respiratory cycle, used mainly for radiation therapy planning of breathing tumors.
Four-horned antelope
Four-horned antelope (Tetracerus quadricornis, chousingha), a small bovid of India and Nepal, the only bovid with four horns; IUCN Vulnerable, about 10,000 remain, protected under Schedule I of India's Wildlife Act.
Four-leaf clover
Four-leaf clover: a rare four-leaflet variant of normally trifoliate clover, mostly white clover (Trifolium repens); recessive trait plus environment, found about 1 in 5,000, a luck symbol.
FOURIER trial
FOURIER (Further Cardiovascular Outcomes Research with PCSK9 Inhibition in Subjects with Elevated Risk) trial: 2017 Amgen-funded randomized trial of evolocumab in 27,564 ASCVD patients; LDL-C fell 59%, primary cardiovascular endpoint reduced 15% (HR 0.85), no significant mortality reduction.
Fournier gangrene
Fournier gangrene, a polymicrobial necrotizing fasciitis of the perineum and genitals described by Jean Alfred Fournier in 1883; treated with urgent debridement and broad-spectrum antibiotics, mortality about 20%, predicted by FGSI and UFGSI scores.
Fourth branchial cleft anomaly
A fourth branchial cleft anomaly, also called a fourth branchial pouch sinus, is a rare congenital neck malformation causing recurrent left-sided neck infections in children.
Fourth nerve palsy
Fourth nerve palsy, also called trochlear nerve palsy, is weakness of the cranial nerve supplying the superior oblique muscle, causing vertical double vision worse when looking down.
Fovea centralis
Fovea centralis: the tiny pit at the center of the macula of the retina, also called the fovea, where cones reach peak density with one-to-one wiring and no blood vessels, giving highest visual acuity; in mammals found only in haplorhine primates.
Foveal hypoplasia-optic nerve decussation defect-anterior segment dysgenesis syndrome
FHONDA syndrome (foveal hypoplasia-optic nerve decussation defect-anterior segment dysgenesis) is a rare autosomal recessive eye disease caused by SLC38A8 mutations, with nystagmus, chiasmal misrouting, and severe foveal hypoplasia but no albinism-related hypopigmentation.
Fovinaciclib citrate capsules
Fovinaciclib citrate capsules (枸橼酸伏维西利胶囊, Futuoning) are a Chinese class 1 oral CDK4/6 inhibitor by Jinzhou Ahon/Fosun, NMPA-approved May 2025 with fulvestrant or aromatase inhibitors for HR+/HER2- advanced breast cancer.
Fowl
Fowl: birds of the orders Galliformes (landfowl, e.g. chickens, turkeys) and Anseriformes (waterfowl, e.g. ducks, geese); domesticated fowl are called poultry, dominated by over 33 billion chickens.
Fowl cholera
Fowl cholera (avian cholera, avian pasteurellosis) is a contagious, often fatal bacterial disease of domestic and wild birds caused by Pasteurella multocida, mainly capsular serotype A, affecting turkeys most severely and controlled by biosecurity and bacterin or live vaccines.
Fowl pox
Fowl pox (fowlpox) is a worldwide, slow-spreading viral disease of chickens and turkeys caused by fowlpox virus, genus Avipoxvirus, with cutaneous and diphtheritic forms, mosquito and wound transmission, and control by live or pigeonpox vaccines.