| low aspect ratio | <physics> An aspect ratio for a torus that is small (minor radius is almost as big as major radius). There are many fusion devices which are designed to have a low aspect ratio. Such devices look more like tractor tires than bicycle tires, as toruses go. There are reasons to believe that low aspect ratio devices will offer some advantages for a fusion reactor. Usually, ease of theoretical and/or numerical analysis is not one of these advantages. (16 Mar 1998) |
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| low back pain | A continuous pain in the lower back or lumbar region. (12 Dec 1998) |
| low-calorie diet | A diet of 1,200 calories or less per day. (05 Mar 2000) |
| low convex | The segment of a sphere of long radius. (05 Mar 2000) |
| low delirium | Delirium in which there is little excitement, either mental or motor, the ideas being confused and incoherent, but following each other slowly. (05 Mar 2000) |
| low density lipoprotein | <biochemistry> A lipoprotein substances (combination of a fat and a protein) which acts as a carrier for cholesterol and fats in the bloodstream. High levels of low density lipoprotein are considered a positive risk factor for the development of coronary artery disease. Less than 130 mg/dl is desirable, 130 to 159 mg/dl is borderline high, over 160 is considered high. Acronym: LDL (10 Jan 1998) |
| low density lipoprotein receptor | <biochemistry> A cell surface protein that mediates the endocytosis of low density lipoprotein by cells. Genetic defects in low density lipoprotein receptors lead to abnormal serum levels of low density lipoprotein and hypercholesterolaemia. (16 Mar 1998) |
| low-density lipoprotein receptors | Receptors on the surface of cells, especially liver cells, which bind to low density lipoprotein and promote clearance of LDL from the plasma. (05 Mar 2000) |
| low-egg-passage vaccine | See: rabies vaccine, Flury strain egg-passage. (05 Mar 2000) |
| low-fat diet | A diet containing minimal amounts of fat.Diets containing low amounts of fat and cholesterol are designed to reduce the risk of heart disease and, in some cases, cancer. Dozens of such diets have been promulgated, both by medical and lay advisors. Their popularity can be attributed in part to clinical studies that have, since the 1980s, revealed, on the one hand, the hazards of eating high-fat, high-cholesterol foods and, on the other, the benefits of ingesting less saturated fat and LDL (low density lipoprotein) cholesterol. Although coronary deaths have been reduced by roughly 30% since 1970, the aim of health officials is to further reduce heart attack rates. The average cholesterol level among adult Americans has fallen from 213 to 205 mg/dl since 1978. However, the National Cholesterol Education Program recommends that individuals maintain a total cholesterol level of no more than 200 mg/dl, with LDL at less than 130 mg/dl and HDL (high density lipoprotein) around 60 mg/dl. About one-half of American adults exceed those recommendations. Low-fat, low-cholesterol diets are rich in whole grains, fresh fruits and vegetables, and legumes, and limit or exclude consumption of processed oils, dairy products, nuts and seeds, and meats. See atherosclerosis, free radicals. (05 Mar 2000) |
| low flow principle | A principle based on the observation that animals can survive prolonged vena caval occlusion without sequelae: if blood from the azygos vein alone is permitted to enter the heart, patients are perfused during cardiac and pulmonary bypass at flows much less than the normal resting cardiac output. Synonym: low flow principle. (05 Mar 2000) |
| low forceps delivery | Delivery by forceps applied to the foetal head after it is clearly visible, the skull has reached the perineal floor, and plus 2 (+2) station. This classification of forceps delivery may be with or without rotation of the foetal head. (05 Mar 2000) |
| low frequency transduction | Specialised transduction in which only a small portion of the prophage particles, because of their defectiveness, are able to develop sufficiently to serve as effective transducing agents. (05 Mar 2000) |
| Low, George | <person> English physician, 1872-1952. See: Castellani-Low sign. (05 Mar 2000) |
| low grade astrocytoma | <tumour> Astrocytoma characterised by an increased cellularity of uneven distribution and mild nuclear pleomorphism. (05 Mar 2000) |