| partial cut | A harvest method in which portions of a stand of timber are cut during a number of entries over time. Precommercial thinning operations are not considered partial cuts. (05 Dec 1998) |
|---|---|
| rose-cut | Cut flat on the reverse, and with a convex face formed of triangular facets in rows; said of diamonds and other precious stones. See Rose diamond, under Rose. Cf. Brilliant. Source: Websters Dictionary (01 Mar 1998) |
| cross-cut bur | A bur with blades located at right angles to its long axis. (05 Mar 2000) |
| cut | In molecular biology, a hydrolytic cleavage of two opposing phosphodiester bonds in a double-stranded nucleic acid. Compare: nick. (05 Mar 2000) |
| bearing down | Expulsive effort of a parturient woman in the second stage of labour. (05 Mar 2000) |
| bearing-down pain | A uterine contraction accompanied by straining and tenesmus; usually appearing in the second stage of labour. (05 Mar 2000) |
| reflex, let down | The let down reflex of the mother is an involuntary reflex during breastfeeding which causes the milk to flow freely. (12 Dec 1998) |
| milk let-down reflex | Release of milk from the breast following tactile stimulation of the nipple; the afferent path is postulated to exist from the nipple to the hypothalamus; the efferent limb is represented by the neurohypophysial release of oxytocin into the systemic circulation; contraction of myoepithelial elements within the breast, caused by oxytocin, moves milk into the collecting ducts and toward the nipple. Synonym: let-down reflex, milk let-down reflex. (05 Mar 2000) |
| cone down | To narrow a beam of X-rays to a region of interest using a collimator or cone; colloq., to delimit one's attention or activities. (05 Mar 2000) |
| head-down tilt | Posture while lying with the head lower than the rest of the body. Extended time in this position is associated with temporary physiologic disturbances. (12 Dec 1998) |
| syndrome, down | A common disorder due to a chromosome abnormality and specfically due to an extra chromosome number 21 (trisomy 21). Down syndrome includes mental retardation, a characteristic face, and multiple malformations. It is associated with a major risk for heart problems, a lesser risk of duodenal atresia (part of the intestines not developed), and a minor but still significant risk of acute leukaemia. The name down syndrome comes from the 19th century english doctor langdon down, a misnomer since he was curiously enough not the first person to describe the condition and, in great error, attributed the condition to a reversion to the mongoloid race. Hence, the old name mongolism, now considered slang. (12 Dec 1998) |
| down | <dermatology, zoology> Fine, soft feathers, soft, fine hair. (04 Mar 1998) |
| Down, John Langdon | <person> English physician, 1828-1896. See: Down's syndrome. (05 Mar 2000) |
| down promoter mutation | <molecular biology> A mutation (a change in base pair sequence) in a promoter region, this results in lower gene expression (less transcription of the gene occurs). (09 Oct 1997) |
| down-regulation | <physiology> Development of a refractory or tolerant state consequent upon repeated administration of a pharmacologically or physiologically active substance. It is the process that decreases ligand and receptor interactions or reduces the responsiveness of a cell to a stimulus following first exposure. This is often accompanied by an initial decrease in affinity of receptors for the agent and a subsequent reduction in the number of available receptors expressed on the surface which can result from internalisation of the ligand:receptor complex or from decreased expression of the receptor. Classically the concept referred to hormone receptors but contemporary usage includes other cell surface receptors. (03 Jul 1999) |