All articles A–Z
519,064 articles
Small for gestational age
Small for gestational age (SGA) describes a fetus or newborn below the 10th weight percentile for gestational age and sex, distinguished from pathological fetal growth restriction, with elevated stillbirth risk and childhood growth follow-up.
Small Form-factor Pluggable
Small Form-factor Pluggable, also known as Mini-GBIC or SFP, is a hot-swappable transceiver module that plugs into network switches and routers to link their circuitry with fiber-optic or copper networks.
Small GTPase
Small GTPase: monomeric 21–30 kDa guanine nucleotide-binding proteins (Ras superfamily: Ras, Rho, Rab, Arf, Ran) acting as GDP/GTP molecular switches regulated by GEFs, GAPs, and GDIs.
Small GTPase Rho
Small GTPase Rho (Ras homolog) family: eukaryotic Ras-superfamily molecular switches (RhoA, Rac1, Cdc42) regulating the actin cytoskeleton, polarity, and migration via GEFs, GAPs, and GDIs; discovered in Aplysia in 1985.
Small heat shock protein IbpA
IbpA (inclusion body protein A) is a 15.7-kDa small heat shock protein of Escherichia coli, encoded with IbpB in the sigma 32-regulated ibpAB operon at 82.5 min; an ATP-independent holdase chaperone that binds aggregates and cooperates with IbpB, DnaK, and ClpB.
Small heat shock protein IbpB
IbpB (inclusion body protein B, ibpB) is a 16 kDa ATP-independent holding chaperone of E. coli; its 2.0–3.0 MDa oligomers dissociate on heat stress to active 600–700 kDa forms that hand substrates to DnaKJE-ClpB.
Small heat-shock protein
Small heat-shock proteins (sHSPs) are ATP-independent molecular chaperones defined by a conserved α-crystallin domain; they trap unfolding proteins to delay aggregation until ATP-dependent chaperones refold them.
Small Heath
Small Heath is an inner-city electoral ward of Birmingham, England, east of the centre along Coventry Road, known for its Pakistani and Bangladeshi communities, high deprivation scores, Small Heath Park, and Small Heath Alliance, the forerunner of Birmingham City F.C.
Small incision cataract surgery
Small incision cataract surgery (MSICS) removes a cataract and implants a lens through a small self-sealing scleral tunnel, delivering the nucleus manually rather than with ultrasound.
Small incision lenticule extraction
Small incision lenticule extraction (SMILE) is a refractive surgery in which a femtosecond laser cuts a disc of tissue inside the cornea, removed through a small incision to correct myopia.
Small Industries Development Bank of India (लघु उद्योग विकास बैंक भारत)
Small Industries Development Bank of India (लघु उद्योग विकास बैंक भारत), or SIDBI, is India's development finance institution for micro, small, and medium enterprises, established in 1990.
Small interfering RNA
Small interfering RNA (siRNA), the ~19–30 bp duplex of RNA interference, guides Argonaute/RISC to cleave matching mRNA; discovered via Fire and Mello's 2006 Nobel work, with patisiran the first FDA-approved siRNA drug (2018).
Small intestinal bacterial overgrowth
Small intestinal bacterial overgrowth (SIBO), also called bacterial overgrowth of the small bowel, is excessive bacteria in the small intestine causing diarrhea, bloating, and malabsorption; diagnosis by jejunal aspirate culture or breath tests is contested.
Small intestinal biopsy
A small intestinal biopsy is a diagnostic procedure that takes mucosal tissue samples from the duodenum during upper endoscopy and examines them under the microscope, principally to diagnose celiac disease.
Small intestine
Small intestine: the 3–5 m duodenum–jejunum–ileum tube between stomach and colon; performs 90–95% of nutrient absorption, absorbs 7–8 of 9 daily liters of water, and shows five molecular regions.
Small Is Beautiful
Small Is Beautiful: Economics as if People Mattered is a 1973 essay collection by economist E. F. Schumacher arguing for human-scale work, technology, and ownership over unlimited growth.
Small Island Developing States
Small Island Developing States (SIDS) are small island and low-lying coastal countries recognized by the United Nations since 1992, totaling 39 states with about 65 million people.
Small kidney
Small kidney (ICD-11 MF54.2; renal hypoplasia or kidney atrophy): a kidney under 11 cm long and 120 g, from congenital underdevelopment or acquired shrinkage from infection, blockage, or vascular disease.
Small kinetochore-associated protein
Small kinetochore-associated protein (SKAP, kinastrin, KNSTRN, UniProt Q9Y448) is a 316-aa microtubule plus-end tracking protein that partners with Astrin to stabilize bioriented kinetochore-microtubule attachments, reduce friction, and support mouse spermatogenesis.
Small Laude
Small Laude (Marissa Eduardo Laude, born 1968) is a Filipino socialite and lifestyle vlogger whose Small's World YouTube channel, started in 2019 at Karen Davila's urging, grew past 2 million subscribers; she also runs Timson Printing with husband Philip Laude and the skincare brand Small Steps Skin.
Small Leucine-Rich Proteoglycans
Small leucine-rich proteoglycans (SLRPs), also called small leucine-rich repeat proteoglycans, are the largest proteoglycan family: 18 members in five classes, 36–42 kDa LRR cores, regulating collagen fibrillogenesis and ECM assembly.
Small lymphocytic lymphoma
Small lymphocytic lymphoma is an indolent cancer of B lymphocytes, mainly in enlarged lymph nodes, the same disease as chronic lymphocytic leukemia with under 5 × 10⁹/L cells in blood.
Small Magellanic Cloud
The Small Magellanic Cloud (Nubecula Minor) is a dwarf irregular galaxy orbiting the Milky Way about 200,000 light-years away, visible to the naked eye from the Southern Hemisphere.
Small modular reactor
A small modular reactor, or SMR, is a nuclear reactor of up to 300 MWe whose modules are fabricated in a factory and shipped to site for assembly.
Small nuclear ribonucleoprotein F
Small nuclear ribonucleoprotein F (snRNP-F, Sm-F, SNRPF) is a core spliceosomal Sm protein forming the heptameric Sm ring of U1, U2, U4, U5, U7 and minor snRNPs, essential for pre-mRNA splicing and snRNP assembly.
Small nuclear ribonucleoprotein G
SNRPG (Sm-G, small nuclear ribonucleoprotein G) is a human 2p13.3 gene encoding an 8.5 kDa Sm core protein of the U1, U2, U4, and U5 snRNPs and the minor U12 spliceosome, assembled by the SMN complex, with reported roles in cancer.
Small nuclear RNA
Small nuclear RNA (snRNA; U1-U6, U11, U12, U4atac, U6atac): 100-300-nucleotide nuclear RNAs forming the catalytic core of major and minor spliceosomes that remove introns from pre-mRNA.
Small nucleolar RNA
Small nucleolar RNA (snoRNA; SNORD/SNORA genes): short non-coding RNAs in the nucleolus that, as box C/D and H/ACA snoRNPs, guide rRNA 2'-O-methylation, pseudouridylation, and pre-rRNA cleavage.
Small nucleolar RNA host gene 1
SNHG1 (small nucleolar RNA host gene 1; UHG, U22HG, LINC00057) is a human lncRNA gene at 11q12.3 hosting eight SNORD snoRNAs, upregulated in many cancers and a proposed prognostic biomarker.
Small nucleolar RNA SNORD115
SNORD115 (HBII-52) is a paternally expressed cluster of about 47 orphan C/D box snoRNA genes at the imprinted 15q11-q13 Prader-Willi locus, with an 18-nt complementarity to HTR2C exon Vb and a modifying interaction with SNORD116.