| 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
| spot seeding | Seeding of woody plant seeds on random spots to blend in with the landscape. (09 Oct 1997) |
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| spot test for infectious mononucleosis | A slide test widely used for the diagnosis of infectious mononucleosis, based on the principle that the heterophil antibodies that occur in the serum of patients with infectious mononucleosis are absorbed by beef red cells but not by guinea pig kidney cells; thus, when horse red cells (which provoke heterophil antibodies) are mixed with patient serum and agglutination occurs in the presence of beef red cells, the presumptive diagnosis is infectious mononucleosis. (05 Mar 2000) |
| Tay's cherry-red spot | The ophthalmoscopic appearance of the normal choroid beneath the fovea centralis, appearing as a red spot surrounded by white retinal oedema in central artery closure or lipid infiltration in sphingolipidosis. Synonym: Tay's cherry-red spot. (05 Mar 2000) |
| temperature spot | One of a number of definitely arranged spot's on the skin sensitive to heat and cold, but not to ordinary pressure or pain stimuli. (05 Mar 2000) |
| tendinous 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) |
| Trousseau's spot | A line of redness resulting from drawing a point across the skin, especially notable in cases of meningitis. Synonym: tache cerebrale, tache meningeale, Trousseau's spot. (05 Mar 2000) |
| yellow 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) |
| kernel spot | <microbiology, plant biology> A fungal disease of pecans that causes irregular brown spots on the nuts, it is caused by Coniothyrum caryogenum. (09 Oct 1997) |
| koplik spot | <dermatology> Small red spots with bluish-white centres on the buccal mucosa (lining of cheek), appearing in the early stages (pre-rash) of measles. (27 Sep 1997) |
| utricular spot | The neuroepithelial sensory receptor in the inferolateral wall of the utricle; hair cells of the neuroepithelium support the statoconial membrane and have terminal arborizations of vestibular nerve fibres around their bodies; sensitive to linear acceleration in the longitudinal axis of the body and to gravitational influences. Synonym: macula utriculi, utricular spot. (05 Mar 2000) |
| flying spot microscope | <instrument> A microscope in which a moving spot of light is imaged in the object plane, the energy transmitted by the specimen being detected with a photoelectric cell; the light source may be a cathode ray tube, a scanning disk or drum, or an oscillating mirror. (05 Mar 2000) |
| focal spot | The site of bombardment by electrons and emission of X-rays from the anode of an X-ray tube. See: focal spot size. (05 Mar 2000) |
| focal spot size | The measured size of a focal spot, a function of its actual size and the angulation of the anode surface. See: focal spot. (05 Mar 2000) |
| forty-spot | <zoology> The Tasmanian forty-spotted diamond bird (Pardalotus quadragintus). Source: Websters Dictionary (01 Mar 1998) |
| Fuchs' black spot | An area of pigment proliferation in the macular region in degenerative myopia. (05 Mar 2000) |