| Harden-Young ester | D-fructose 1,6-bisphosphate;important intermediate in sugar metabolism. (05 Mar 2000) |
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| young | 1. Not long born; still in the first part of life; not yet arrived at adolescence, maturity, or age; not old; juvenile; said of animals; as, a young child; a young man; a young fawn. "For he so young and tender was of age." (Chaucer) ""Whom the gods love, die young," has been too long carelessly said; . . . Whom the gods love, live young forever." (Mrs. H. H. Jackson) 2. Being in the first part, pr period, of growth; as, a young plant; a young tree. "While the fears of the people were young." (De Foe) 3. Having little experience; inexperienced; unpracticed; ignorant; weak. "Come, come, elder brother, you are too young in this." (Shak) Origin: OE. Yung, yong, yong, yung, AS. Geong; akin to OFries. Iung, iong, D. Joing, OS, OHG, & G. Jung, Icel. Ungr, Sw. & Dan. Ung, Goth. Juggs, Lith. Jaunas, Russ. Iunuii, L. Juvencus, juvenis, Skr. Juvaca, juvan. Cf. Junior, Juniper, Juvenile, Younker, Youth. Source: Websters Dictionary (01 Mar 1998) |
| Young-Helmholtz theory of colour vision | A theory that there are three colour-perceiving elements in the retina: red, green, and blue. Perception of other colours arises from the combined stimulation of these elements; deficiency or absence of any one of these elements results in inability to perceive that colour and a misperception of any other colour of which it forms a part. Synonym: Helmholtz theory of colour vision. (05 Mar 2000) |
| Young, Hugh | <person> U.S. Urologist, 1870-1945. See: Young prostatic tractor. (05 Mar 2000) |
| Young prostatic tractor | A short, straight tubular instrument with blades at its tip, which can be rotated open and closed; it is passed into the prostatic urethra, through a prostatotomy incision made during the later stages of open perineal prostatectomy, with its tip into the bladder; direct traction on the instrument brings the prostate gland down into the operative field where enucleation can be more easily performed. (05 Mar 2000) |
| Young's rule | An obsolete rule to determine a child's dose: 12 is added to the child's age and the sum is divided by the age; the adult dose divided by the figure so obtained gives the proper dose. (05 Mar 2000) |
| Young syndrome | <syndrome> Obstructive azoospermia and chronic sinopulmonary infections. (05 Mar 2000) |
| Young, Thomas | <person> English physician and physicist, 1773-1829. See: Young's modulus, Young's rule, Young-Helmholtz theory of colour vision. (05 Mar 2000) |
| Young, William | <person> 20th century Australian biochemist. See: Harden-Young ester. (05 Mar 2000) |
| a-form DNA | <molecular biology> One of several forms that can be assumed by a double helix. A-DNA is stable in dehydrated conditions. This form is less common than the dominant form found under physiological conditions -- beta-DNA. This form is also assumed by DNA-RNA hybrid helices and by regions of double-stranded RNA. It is a right-handed helix and is a more compact form than beta-DNA. (09 Oct 1997) |
| boat form | The less stable of two conformations assumed by 6-membered cyclic sugars (pyranoses) or cyclohexane derivatives, as opposed to chair form. See: Haworth conformational formulas of cyclic sugars. (05 Mar 2000) |
| cavity preparation form | The configuration or shape of a cavity preparation. (05 Mar 2000) |
| replicative form | An intermediate stage in the replication of either DNA or RNA viral genomes that is usually double stranded, the altered, double-stranded form to which single-stranded coliphage DNA is converted after infection of a susceptible bacterium, formation of the complementary ("minus") strand being mediated by enzymes that were present in the bacterium before entrance of the viral ("plus") strand. (05 Mar 2000) |
| resistance form | The shape given to a cavity preparation that enables the dental restoration to withstand masticatory forces. (05 Mar 2000) |
| retention form | The shape of a cavity preparation that prevents displacement of the dental restoration by lateral or tipping forces as well as masticatory forces. (05 Mar 2000) |