| Rf | in paper or thin-layer chromatography, the distance that a spot of a substance has moved from the po... |
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| YS | yellow spot; yolk sac |
| ys | yellow spot; yolk sac |
pin-head pigmentation spot
| cherry-red spot myoclonus syndrome | <syndrome> A neuronal storage disorder in children characterised by a cherry red spot at the macula, progressive myoclonus, and easily controlled seizures; the result of sialidase deficiency. Type 1 is characterised by normal body habitus, cherry red macula, myoclonus, and normal beta-galactosidase levels; type 2 by short stature, bony abnormalities, and deficient beta-galactosidase. Synonym: sialidosis. (05 Mar 2000) |
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| mongolian spot | <dermatology> A benign bluish or bruised-appearing birthmark that is usually located on the lower back or buttocks. More common in dark-skinned races and may persist for months to years. (27 Sep 1997) |
| white spot | Gray-white or white, rounded or irregularly shaped, slightly opaque patches or spots that are sometimes observed postmortem in the epicardium, especially in middle-aged or older persons; they result from fibrous thickening, and sometimes hyalinization, of the epicardium; similar lesions may also occur in the visceral layer of the peritoneum. Synonym: macula lactea, macula tendinea, tache blanche, tache laiteuse, tendinous spot, white spot. (05 Mar 2000) |
| white spot disease | Small discrete, white, waxy, indurated lesions due to localised degenerative changes in the fibrous tissue. Synonym: white spot disease. (05 Mar 2000) |
| corneal spot | A moderately dense opacity of the cornea. Synonym: corneal spot. (05 Mar 2000) |
| saccular spot | The oval neuroepithelial sensory receptor in the anterior wall of the saccule; hair cells of the neuroepithelium support the statoconial membrane and have terminal arborizations of vestibular nerve fibres around their bodies. Synonym: macula sacculi, saccular spot. (05 Mar 2000) |
| helminthosporium leaf spot | A plant disease affecting some grasses which is caused by parasitic fungi from the genus Helminthosporium and which appears as discoloured spots. (09 Oct 1997) |
| hot spot | <molecular biology> A particular area of DNA which is especially prone to spontaneous mutations or recombinations. (09 Oct 1997) |
| hypnogenic spot | A pressure-sensitive point on the body of certain susceptible persons, which, when pressed, causes the induction of sleep. (05 Mar 2000) |
| Soemmerring's spot | An oval area of the sensory retina, 3 by 5 mm, temporal to the optic disk corresponding to the posterior pole of the eye; at its centre is the central fovea, which contains only retinal cones. Synonym: area centralis, macula lutea, macular area, punctum luteum, Soemmerring's spot, yellow spot. (05 Mar 2000) |
| spot | 1. A mark on a substance or body made by foreign matter; a blot; a place discoloured. "Out, damned spot! Out, I say!" (Shak) 2. A stain on character or reputation; something that soils purity; disgrace; reproach; fault; blemish. "Yet Chloe, sure, was formed without a spot." (Pope) 3. A small part of a different colour from the main part, or from the ground upon which it is; as, the spots of a leopard; the spots on a playing card. 4. A small extent of space; a place; any particular place. "Fixed to one spot." "That spot to which I point is Paradise." (Milton) ""A jolly place," said he, "in times of old! But something ails it now: the spot is cursed."" (Wordsworth) 5. <zoology> A variety of the common domestic pigeon, so called from a spot on its head just above its beak. 6. <zoology> A sciaenoid food fish (Liostomus xanthurus) of the Atlantic coast of the United States. It has a black spot behind the shoulders and fifteen oblique dark bars on the sides. Called also goody, Lafayette, masooka, and old wife. The southern redfish, or red horse, which has a spot on each side at the base of the tail. See Redfish. 7. Commodities, as merchandise and cotton, sold for immediate delivery. Crescent spot, the Hudsonian godwit (Limosa haemastica). Spots on the sun. <astronomy> See Sun spot, ander Sun. On, or Upon, the spot, immediately; before moving; without changing place. "It was determined upon the spot." (Swift) Synonym: Stain, flaw, speck, blot, disgrace, reproach, fault, blemish, place, site, locality. Origin: Cf. Scot. & D. Spat, Dan. Spette, Sw. Spott spittle, slaver; from the root of E. Spit. See Spit to eject from the mouth, and cf. Spatter. Source: Websters Dictionary (01 Mar 1998) |
| spot desmosome | <cell biology> Macula adherens: See: desmosome. Origin: Gr. Soma = body (18 Nov 1997) |
| spot film | A radiograph made during the course of an examination under fluoroscopic control, with a device attached to the fluoroscope. (05 Mar 2000) |
| spot-film radiography | An X-ray of a localised region, usually under study by fluoroscopy. (05 Mar 2000) |
| spot seeding | Seeding of woody plant seeds on random spots to blend in with the landscape. (09 Oct 1997) |