| daphnin | <chemistry> A dark green bitter resin extracted from the mezereon (Daphne mezereum) and regarded as the essential principle of the plant. A white, crystalline, bitter substance, regarded as a glucoside, and extracted from Daphne mezereum and D. Alpina. Origin: Cf. F. Daphnine. Source: Websters Dictionary (01 Mar 1998) |
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| daphnomancy | Divination by means of the laurel. Origin: Gr. Dafnh the laurel + -mancy. Source: Websters Dictionary (01 Mar 1998) |
| DAPI | <abbreviation> 4'6-diamidino-2-phenylindole-2HCl, a fluorescent probe for DNA. See: DAPI stain. (05 Mar 2000) |
| DAPI stain | <technique> A sensitive fluorescent probe for DNA, 4'6-diamidino-2-phenylindole-2HCl, used in fluorescence microscopy to detect DNA in yeast mitochondria, chloroplasts, viruses, mycoplasma, and chromosomes; DNA is visualised in vitally stained living cells and after cells are fixed in formaldehyde. (05 Mar 2000) |
| dapsone | <drug> Related to the sulphonamides (diaminodiphenyl sulphone) that is used to treat leprosy (of which the causative agent is Mycobacterium leprae). May act by inhibiting folate synthesis. (18 Nov 1997) |
| dapsone neuropathy | A peripheral neuropathy that develops in patients taking dapsone (4,4-diaminodiphenylsulfone); unusual features include being a pure motor neuropathy, and beginning in the hands, sometimes asymmetrically. (05 Mar 2000) |
| daptomycin | <chemical> A lipopeptide antibiotic that inhibits gram-positive bacteria. Pharmacological action: antibiotics, peptide. Chemical name: Daptomycin (12 Dec 1998) |
| dare | To have adequate or sufficient courage for any purpose; to be bold or venturesome; not to be afraid; to venture. "I dare do all that may become a man; who dares do more is none." (Shak) "Why then did not the ministers use their new law? Bacause they durst not, because they could not." (Macaulay) "Who dared to sully her sweet love with suspicion." (Thackeray) "The tie of party was stronger than the tie of blood, because a partisan was more ready to dare without asking why." (Jowett (Thuyd)) The present tense, I dare, is really an old past tense, so that the third person is he dare, but the form he dares is now often used, and will probably displace the obsolescent he dare, through grammatically as incorrect as he shalls or he cans. "The pore dar plede (the poor man dare plead)." (P. Plowman) "You know one dare not discover you." (Dryden) "The fellow dares nopt deceide me." (Shak) "Here boldly spread thy hands, no venom'd weed Dares blister them, no slimly snail dare creep." (Beau. & Fl) Formerly durst was also used as the present. Sometimes the old form dare is found for durst or dared. Origin: OE. I dar, dear, I dare, imp. Dorste, durste, AS. Ic dear I dare, imp. Dorste. Inf. Durran; akin to OS. Gidar, gidorsta, gidurran, OHG. Tar, torsta, turran, Goth. Gadar, gadaorsta, Gr. Tharsei^n, tharrei^n, to be bold, tharsys bold, Skr. Dhrsh to be bold. To terrify; to daunt. "For I have done those follies, those mad mischiefs, Would dare a woman." (Beau. & Fl) To dare larks, to catch them by producing terror through to use of mirrors, scarlet cloth, a hawk, etc, so that they lie still till a net is thrown over them. <zoology> A small fish; the dace. See: Dace. Source: Websters Dictionary (01 Mar 1998) |
| Darier | Jean F., French dermatologist, 1856-1938. See: Darier's disease, Darier's sign. (05 Mar 2000) |
| Darier's disease | A slowly progressive autosomal dominant disorder of keratinization characterised by pinkish-to-tan papules that coalesce to form plaques. These lesions become darker over time and commonly fuse, forming papillomatous and warty malodorous growths. (12 Dec 1998) |
| Darier's sign | <clinical sign> Urtication on stroking of cutaneous lesions of urticaria pigmentosa (mastocytosis). (05 Mar 2000) |
| dark adaptation | The adjustment of the eye occurring under reduced illumination in which the sensitivity to light is greatly increased or the light threshold is greatly reduced. Dark adaptation is slower than light adaptation. During dark adaptation rhodopsin is built up in the retinal rods. (12 Dec 1998) |
| dark cell | Cell's in eccrine sweat glands having many ribosomes and mucoid secretory granules. (05 Mar 2000) |
| dark current | <physiology> Current caused by constant influx of sodium ions into the rod outer segment of retinal photoreceptors and that is blocked by light (leading to hyperpolarization). The plasma membrane sodium channel is controlled through a cascade of amplification reactions initiated by photon capture by rhodopsin in the disc membrane. (18 Nov 1997) |
| dark field illumination | <microscopy> Any method of illumination which illuminates the specimen but does not admit light directly to the objective. It may be by substage (dark field) condensers, by stagespot lighting, by special condensers fitted around special objectives for reflected illumination or by the slit ultramicroscope. (05 Aug 1998) |