| GRASS | gradient recalled acquisition in a steady state |
|---|---|
| GRE | glucocorticoid response element; gradient-recalled echo; Graduate Record Examination |
| HVPG | hepatic venous pressure gradient |
| IAPG | interatrial pressure gradient |
| MDG | mean diastolic gradient; methyladenine deoxyribonucleic acid glycosylase |
| continuous variable | A variable that may take on any value in an interval or intervals (its domain). (05 Mar 2000) |
|---|---|
| bone density | Bone density is the amount of bone tissue in a certain volume of bone. It can be measured using a special X-ray called a quantitative computed tomogram. (12 Dec 1998) |
| bulk density | Weight per unit of volume, usually specified in pounds per cubic foot. (05 Dec 1998) |
| buoyant density | The density that allows a substance to float in some standard fluid. (05 Mar 2000) |
| vapor density | The mass per unit volume of a vapor; since the vapor density changes with temperature and pressure, it is commonly expressed as a specific gravity, i.e., the weight of the vapor divided by the weight of an equal volume of a reference gas (e.g., oxygen or hydrogen) at the same temperature and pressure. (05 Mar 2000) |
| very low density lipoprotein | <biochemistry> A lipoprotein substances (combination of a fat and a protein) which acts as a carrier for cholesterol and fats (particularly triglycerides) in the bloodstream. Elevations in very low density lipoprotein in the bloodstream are associated with an increased risk of atherosclerosis and coronary artery disease. Acronym: VLDL (18 Nov 1997) |
| photon density | The number of counted events recorded in scintigraphy per square centimeter or per square inch of imaged area. Synonym: count density. (05 Mar 2000) |
| count density | The number of counted events recorded in scintigraphy per square centimeter or per square inch of imaged area. Synonym: count density. (05 Mar 2000) |
| population density | <epidemiology> Number of individuals in a population relative to space. (12 Dec 1998) |
| current density | <radiobiology> Amount of current flowing through a substance, per unit area perpendicular to the direction of current flow. (See also density) (09 Oct 1997) |
| high density lipoprotein | <biochemistry> These lipoproteins acts to carry cholesterol in the bloodstream. Raised high density lipoprotein levels have been correlated with a lower risk for heart disease. Less than 35 mg/dl is considered a positive risk factor for coronary artery disease, over 60 mg/dl is considered a negative risk factor (reduces your risk of heart disease). Recent studies show a low high density lipoprotein level is the strongest predictor of cardiovascular death in women. Acronym: HDL (18 Nov 1997) |
| spin density | The number of nuclear dipoles per unit volume. (05 Mar 2000) |
| stand density | The number or mass of trees occupying a site. It is usually measured in terms of stand density index or basal area per acre. (05 Dec 1998) |
| neutral-density filter | <equipment> A light-absorbing filter whose absorption spectrum is moderately flat. Depending on the type, the absorption curve is flat primarily in the visible spectral range, or may extend to varying degrees beyond the visible range. For video microscopy, this is an important point since the absorbance may or may not extend into the near-infrared region where the sensitivity of many video image pickup devices is very high. (05 Aug 1998) |
| density | 1. <radiology> The amount of darkness or light in an area of a scan reflects the compactness and density of tissue. Differences in tissue density are the basis for CT and MR scans. 2. <microscopy> Logarithm to the base 10 of the reciprocal of transmittance. (12 Jan 1998) |