| double layer | <physiology> The zone adjacent to a charged particle in which the potential falls effectively to zero. An excess or deficiency of electrons on the surface (charge, not to be confused with the transmembrane potential) leads to an equivalent excess of ions of the opposite charge in the surrounding fluid. For most cells, that have negative charges, there will be an excess of cations immediately adjacent to the plasma membrane and at physiological ionic strength the double layer is likely to be around 2-3 nm thick. (10 Oct 1997) |
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| double lip | Congenital or acquired excess tissue on the inner mucosal aspect of the lip; may be a manifestation of Ascher's syndrome. (05 Mar 2000) |
| double loop hernia | The presence of two loops of intestine in a hernial sac. Synonym: double loop hernia. (05 Mar 2000) |
| double-masked experiment | A double-blind study conducted so neither the subject nor the observer know the identity of the control or variable. (05 Mar 2000) |
| double membrane | <cell biology> Two biomembrane layers, with an intermembranal space, surrounding certain organelles (e.g., mitochondria) or structures. (05 Mar 2000) |
| double minute | <molecular biology> Small pieces of a chromosome containing many copies of the same gene. (09 Oct 1997) |
| double minute chromosomes | <genetics, molecular biology> Paired, extrachromosomal elements lacking centromeres, often associated with a drug resistance gene. (05 Mar 2000) |
| double-mouthed uterus | Septate uterus in which the cervix is divided into two by a septum. Synonym: double-mouthed uterus, uterus biforis. (05 Mar 2000) |
| double outlet right ventricle | <cardiology, embryology> Incomplete transposition of the great vessels in which both the aorta and the pulmonary artery arise from the right ventricle, often associated with a subaortic ventricular septal defect. (12 Dec 1998) |
| double pedicle flap | A flap with two pedicles, one at each end. Synonym: double pedicle flap. (05 Mar 2000) |
| double pleurisy | Inflammation of the pleura on both sides of the thorax. Synonym: double pleurisy. (05 Mar 2000) |
| double-point threshold | The least degree of separation of two points applied to the body surface that permits of their being felt as two. (05 Mar 2000) |
| double product | The product of systolic blood pressure multiplied by the heart frequency; a measure of heart work load. See: Robinson index. (05 Mar 2000) |
| double protrusion | The excessive forward projection of both the maxilla and the mandible in relation to the cranial base. Synonym: double protrusion. (05 Mar 2000) |
| double quotidian fever | Malaria in which two paroxysms of fever occur daily. (05 Mar 2000) |