All articles starting with S
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Suppressor (firearms)
A suppressor, also called a silencer or sound moderator, is a muzzle device that cuts gunshot noise by about 3 to 35 dB, though the shot stays audible.
Suppressor Genes
Suppressor genes are genes carrying a suppressor allele or mutation that cancels the effect of a previous mutation, restoring the wild-type phenotype; distinct from tumor suppressor genes.
Suppressor of fused
Suppressor of fused (SUFU, Sufu) is a conserved negative regulator of Hedgehog signaling that sequesters GLI1-3 transcription factors in the cytoplasm; discovered in Drosophila as a fused suppressor, essential in mouse development, a tumor suppressor linked to medulloblastoma.
Suprabasal cell
Suprabasal cell: epithelial cell in layers above the basal layer of stratified or pseudostratified epithelia (skin, esophagus, airway, cornea); arises from basal cells, expresses differentiation keratins, and is committed to terminal differentiation.
Supracervical hysterectomy
Supracervical hysterectomy is an operation that removes the uterine corpus while leaving the cervix in place, used mainly for benign disorders such as fibroids and abnormal bleeding.
Suprachiasmatic nucleus
Suprachiasmatic nucleus (SCN), hypothalamic master circadian pacemaker above the optic chiasm, ~20,000 neurons, intrinsic period ~24.2 h, light-entrained via the retinohypothalamic tract, synchronizes peripheral clocks and melatonin rhythms.
Supraclavicular brachial plexus block
The supraclavicular brachial plexus block, or supraclavicular block, is a regional anesthesia technique injecting local anesthetic above the clavicle to numb the arm and shoulder.
Supraclavicular lymph nodes
Supraclavicular lymph nodes (nodi lymphoidei supraclaviculares): 4-12 nodes above the clavicle draining breast, lung, esophagus, and abdomen; the left Virchow node (Troisier sign) signals metastatic cancer in 54-85% of enlargements.
Supracondylar fracture of humerus
Supracondylar humerus fracture, pediatric distal humerus fracture above the elbow, most common childhood elbow injury, Gartland types I-IV, treated by casting or closed reduction with percutaneous pinning.
Supraglacial lake
Supraglacial lakes are meltwater ponds on glacier and ice-sheet surfaces in Greenland and Antarctica. They store runoff, drain by hydrofracture or overflow, modulate ice flow, and can trigger ice-shelf breakup.
Supraglottoplasty
Supraglottoplasty is a surgical procedure in otolaryngology that removes or reduces abnormal supraglottic laryngeal tissue to relieve the airway obstruction caused by laryngomalacia, the most common cause of stridor in infants.
Supramalleolar osteotomy
Supramalleolar osteotomy is a joint-preserving orthopedic procedure that cuts and realigns the tibia just above the ankle to shift load onto preserved cartilage in asymmetric ankle arthritis.
Supramolecular polymer
A supramolecular polymer is a polymeric array of monomeric units held together by reversible noncovalent interactions like hydrogen bonding, first proposed by Jean-Marie Lehn in 1990.
Supramolecular polymerization
Supramolecular polymerization is the reversible assembly of monomers into polymeric arrays through directional noncovalent interactions such as hydrogen bonds and metal coordination, giving stimuli-responsive, self-healing materials.
Supramolecular tandem assay
A supramolecular tandem assay is a label-free method for monitoring enzyme activity in real time, using a macrocyclic host and fluorescent dye whose displacement reports the enzymatic conversion.
Supranational union
Supranational union: an organization of states with common institutions whose binding decisions apply directly in members, as in the EU; contrasted with intergovernmental bodies like ASEAN and hybrid cases like the African Union.
Suprapubic cystostomy
Suprapubic cystostomy is a urological procedure that places a catheter through the lower abdominal wall into the bladder to drain urine, used when urethral catheterization is not possible.
Suprascapular nerve block
A suprascapular nerve block (SSNB) is a regional anesthesia procedure injecting local anesthetic near the suprascapular nerve, which carries about 70% of shoulder sensation, to relieve shoulder pain.
Supraspinatus muscle
Supraspinatus muscle: rotator cuff muscle of the shoulder, originating in the supraspinous fossa of the scapula and inserting on the greater tubercle of the humerus; initiates 0-15 degrees of arm abduction, innervated by the suprascapular nerve (C5, C6), and the cuff tendon most prone to tears.
Supratrochlear lymph nodes
Supratrochlear (epitrochlear, cubital) lymph nodes: 1–2 superficial nodes 4–5 cm above the medial epicondyle draining the medial fingers and forearm to the axilla; palpable nodes over 0.5 cm are abnormal.
Supravalvular aortic stenosis
Supravalvular aortic stenosis (SVAS), also called supravalvar aortic stenosis or elastin arteriopathy, is congenital narrowing of the ascending aorta above the aortic valve, caused by ELN gene mutation or deletion at 7q11.23, alone or in Williams-Beuren syndrome.
Supraventricular tachycardia
Supraventricular tachycardia (SVT): fast heart rhythms above 100 bpm arising at or above the His bundle, including AVNRT, AVRT, and focal atrial tachycardia; atrial fibrillation excluded. Treated with adenosine acutely and catheter ablation curatively.
Supremacism
Supremacism is the ideology that one group of people is superior and entitled to rule or dominate others, whether by race, religion, gender, or culture.
Supremacy (film)
Supremacy (2014) is an American drama thriller directed by Deon Taylor, written by Eric J. Adams, starring Joe Anderson, Danny Glover, and Dawn Olivieri, based on a 1995 Sonoma County Aryan Brotherhood hostage case.
Supremacy Clause
The Supremacy Clause (Article VI, Clause 2) makes the Constitution, federal laws, and treaties the supreme Law of the Land, binding state judges and grounding federal preemption doctrine.
Suprematism
Suprematism, or suprematism (супрематизм), is the geometric abstract art movement founded by Kazimir Malevich in 1915, first shown at the 0.10 exhibition in Petrograd, claiming the supremacy of pure feeling over depiction.
Supreme (brand)
Supreme is a New York streetwear and skateboarding brand founded by James Jebbia in April 1994 on Lafayette Street, known for its red box logo, Thursday drops, and ownership changes from Carlyle to VF to EssilorLuxottica.
Supreme (film)
Supreme (సుప్రీమ్) is a 2016 Telugu action comedy directed by Anil Ravipudi, starring Sai Dharam Tej as taxi driver Balu protecting an orphaned heir from mafia boss Vikram Sarkar; released 5 May 2016, a hit.
Supreme Allied Commander
Supreme Allied Commander is the title of NATO's two strategic commanders: SACEUR, leading all NATO operations from SHAPE in Mons, Belgium, traditionally a US officer dual-hatted as EUCOM commander, first held by Eisenhower in 1950; and SACT, held by a French officer since 2009.
Supreme Allied Commander Europe
Supreme Allied Commander Europe (SACEUR): NATO's senior strategic commander, head of Allied Command Operations at SHAPE, Mons, Belgium; always an American officer dual-hatted as Commander US European Command; first held by Eisenhower (1950), currently General Alexus G. Grynkewich since 4 July 2025.