| 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) |
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| 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) |
| 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) |
| pulsed-field gel electrophoresis | Gel electrophoresis in which, after electrophoretic migration has begun, the current is briefly stopped and reapplied in a different orientation; allows for the purification of long DNA molecules. Synonym: pulsed-field gel electrophoresis. (05 Mar 2000) |
| pulse-field gel electrophoresis | Gel electrophoresis in which, after electrophoretic migration has begun, the current is briefly stopped and reapplied in a different orientation; allows for the purification of long DNA molecules. Synonym: pulsed-field gel electrophoresis. (05 Mar 2000) |
| electrophoresis, agar gel | Electrophoresis in which agar or agarose gel is used as the diffusion medium. (12 Dec 1998) |
| electrophoresis, gel, pulsed-field | Electrophoresis in which the direction of the electric field is changed periodically. This technique is similar to other electrophoretic methods normally used to separate double-stranded DNA molecules ranging in size up to tens of thousands of base-pairs. However, by alternating the electric field direction one is able to separate DNA molecules up to several million base-pairs in length. (12 Dec 1998) |
| electrophoresis, gel, two-dimensional | Electrophoresis in which a second perpendicular electrophoretic transport is performed on the separate components resulting from the first electrophoresis. This technique is usually performed on polyacrylamide gels. (12 Dec 1998) |
| electrophoresis, polyacrylamide gel | Electrophoresis in which a polyacrylamide gel is used as the diffusion medium. (12 Dec 1998) |
| electrophoresis, starch gel | Electrophoresis in which a starch gel (a mixture of amylose and amylopectin) is used as the diffusion medium. (12 Dec 1998) |
| two dimensional gel electrophoresis | <technique> A high resolution separation technique in which protein samples are separated by isoelectric focussing in one dimension and then laid on an SDS gel for size determined separation in the second dimension. Can resolve hundreds of components on a single gel. (18 Nov 1997) |
| atrioventricular gradient | The diastolic pressure difference between the atrium and ventricle. (05 Mar 2000) |
| magnetic 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) |
| ventricular gradient | The algebraic sum of (i.e., the net electrical difference between) the area enclosed within the QRS complex and that within the T wave in the electrocardiogram. (05 Mar 2000) |
| voltage gradient | <physiology> Literally, the electric field in a region, defined as the potential difference between two points divided by the distance between them. Used more loosely, the potential difference across a plasma membrane. (18 Nov 1997) |