| negative regulation | Negative feedback in biological systems mediated by allosteric regulatory enzymes. (18 Nov 1997) |
|---|---|
| negative S | Characteristic sedimentation behaviour of a lipoprotein fraction of plasma in a centrifugal field in a medium of appropriate density, achieved by adding a salt or D2O to the plasma. Synonym: negative S, Svedberg of flotation. (05 Mar 2000) |
| negative scotoma | A scotoma that is not ordinarily perceived, but is detected only on examination of the visual field. (05 Mar 2000) |
| negative stain | <technique> Stain forming an opaque or coloured background against which the object to be demonstrated appears as a translucent or colourless area; in electron microscopy, an electron opaque material, such as phosphotungstic acid or sodium phosphotungstate, is used to give detail as to surface structure. (05 Mar 2000) |
| negative staining | Microscopic technique in which the object stands out against a dark background of stain. For electron microscopy the sample is suspended in a solution of an electron dense stain such as sodium phosphotungstate and then sprayed onto a support grid. The stain dries as structureless solid and fills all crevices in the sample. When examined in the electron microscope the sample appears as a light object against a dark background. Quite fine structural detail can be observed using negative staining and it has been used extensively to study the structure of viruses and other particulate samples. (18 Nov 1997) |
| negative strand virus | A virus the genome of which is a strand of RNA that is complementary to messenger RNA; negative strand virus's also carry RNA polymerases necessary for the synthesis of messenger RNA. (05 Mar 2000) |
| negative stranded RNA virus | <virology> Class V viruses that have an RNA genome that is complementary to the mRNA, the positive strand. They also carry the virus specific RNA polymerase necessary for the synthesis of the mRNA. Includes (Rhabdoviridae, Paramyxoviridae and Myoviridae (for example the T even phages). (18 Nov 1997) |
| negative taxis | The repulsion of protoplasm away from a stimulus. (05 Mar 2000) |
| negative thermotaxis | Repulsion of a plant or animal from heat. (05 Mar 2000) |
| negative transference | Transference characterised by predominantly hostile feelings on the part of the patient toward the analyst. (05 Mar 2000) |
| negative, false | A result that appears negative but fails to reveal a situation. An example of a false negative: a particular test designed to detect cancer of the toenail is negative but the person has toenail cancer. (12 Dec 1998) |
| negatively | 1. In a negative manner; with or by denial. "He answered negatively." 2. In the form of speech implying the absence of something; opposed to positively. " shal show what this image of God in man is, negatively, by showing wherein it does not consist, and positively, by showing wherein it does consist. <physics>" (South) Negatively charged or electrified, having a charge of the kind of electricity called negative. Source: Websters Dictionary (01 Mar 1998) |
| negatively bathmotropic | Lessening nervous or muscular irritability. (05 Mar 2000) |
| negatively dromotropic | Acting to diminish conduction velocity. (05 Mar 2000) |
| negativism | State of mind or behaviour characterised by extreme skepticism and persistent opposition or resistance to outside suggestions or advice. (12 Dec 1998) |