| density gradient centrifugation | <technique> High-speed centrifugation inwhich molecules float at a point wheretheir density equals that in a gradient of cesium chloride or sucrose. (12 Jan 1998) |
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| systolic gradient | The difference in pressure during systole between two communicating cardiovascular chambers, e.g., between the left ventricle and aorta in aortic stenosis. (05 Mar 2000) |
| electrochemical gradient | A measure of the tendency of an ion to move passively from one point to another, taking into consideration the differences in its concentration and in the electrical potentials between the two points; commonly expressed as the additional voltage needed to achieve equilibrium. (05 Mar 2000) |
| ficoll gradient | A density gradient of ficoll (synthetic sucrose polymer) in solution, where concentration of the ficoll varies continuously through the solution. It is often used to separate different types of cells from each other during the process of sedimentation. (09 Oct 1997) |
| field gradient | In magnetic resonance imaging, a magnetic field that varies with location, superimposed on the uniform field of the magnet, to alter the resonant frequency of nuclei and allow recovery of their spatial position. Synonym: field gradient. (05 Mar 2000) |
| agarose gel electrophoresis | <procedure> A type of electrophoresis that uses a matrix of highly purified agar to separate large nucleotides in size. (06 May 1997) |
| blood protein electrophoresis | Electrophoresis applied to blood proteins. (12 Dec 1998) |
| capillary electrophoresis | A technique for separating compounds, a sample of a compound to beseparated is placed in a capillary tube, which is then subjected to ahigh voltage current that separates its chemical components. (09 Oct 1997) |
| capillary zone electrophoresis | A method for separating molecules extremely rapidly based on their electrophoretic mobility. (05 Mar 2000) |
| gamaglobulin electrophoresis | <investigation> A test that detects and measures the various immunoglobulins in the blood. In the normal assay no monoclonal antibodies are detected. In multiple myeloma and chronic lymphocytic leukaemia a single clone of lymphocytes can produce one type of immunoglobulin that is detected in the electrophoresis as monoclonal (made by one cell clone). (27 Sep 1997) |
| gel electrophoresis | <molecular biology> Electrophoresis using a gel supporting phase. Usually applied to systems where the gel is based on polyacrylamide. See: electrophoresis. (05 May 1997) |
| carrier electrophoresis | Electrophoresis done on a carrier (such as paper, polyacrylamide gel, etc.). (05 Mar 2000) |
| cell electrophoresis | <technique> A method for estimating the surface charge of a cell by looking at its rate of movement in an electrical field. Almost all eukaryotic cells have a net negative surface charge. Measurement is complicated by the streaming potential at the wall of the chamber itself and by the fact that the cell is surrounded by a layer of fluid (see double layer). The electrical potential measured (the zeta potential) is actually some distance away from the plasma membrane. One of the more useful modifications is to systematically vary the pH of the suspension fluid to determine the pK of the charged groups responsible (mostly carboxyl groups of sialic acid). (26 Mar 1998) |
| multi locus enzyme electrophoresis | Inhibition of translation of the transcript of a transposase gene by a multicopy plasmid with suitable inhibitory gene. The plasmid inhibits transposition events in the host bacterium. (18 Nov 1997) |
| polyacrylamide gel electrophoresis | Analytical and separative technique in which molecules, particularly proteins, are separated by their different electrophoretic mobilities in a hydrated gel. The gel suppresses convective mixing of the fluid phase through which the electrophoresis takes place and contributes molecular sieving. Commonly carried out in the presence of the anionic detergent sodium dodecylsulphate (SDS). SDS denatures proteins so that noncovalently associating sub unit polypeptides migrate independently and by binding to the proteins confers a net negative charge roughly proportional to the chain weight. See: SDS PAGE. (21 Jun 1999) |