| N(H) | proton density |
|---|---|
| PIXE | particle-induced x-ray emission; proton-induced x-ray emission |
| PMF | platelet membrane fluidity; progressive massive fibrosis; proton motive force; pterygomaxillary foss... |
| pmf | proton motive force |
| PT | pain threshold; parathormone; parathyroid; paroxysmal tachycardia; part time; patient; pericardial t... |
| contrast enhancement | The intravenous administration of water-soluble iodinated contrast material, which increases the CT number of the vascular pool, as well as some lesions (particularly in the brain), due to abnormal leakage into the interstitium; the property of showing increased radiopacity from concentration of contrast medium. (05 Mar 2000) |
|---|---|
| image enhancement | Improvement of the quality of a picture by various techniques, including computer processing, digital filtering, echocardiographic techniques, light and ultrastructural microscopy, fluorescence spectrometry and microscopy, scintigraphy, and in vitro image processing at the molecular level. (12 Dec 1998) |
| immunological enhancement | In immunology, the potentiating effect of specific antibody in establishing and in delaying rejection of a tumour allograft; aside from antibody, non-specific substances may also act to enhance immune response. Synonym: immunological enhancement. (05 Mar 2000) |
| edge enhancement | Using analogue or digital image processing to increase the contrast of each interface; equivalent to using a high-pass filter. (05 Mar 2000) |
| enhancement | Altering an object, substance or site for the improvement of a specific value. (09 Oct 1997) |
| enhancement effect | Property of higher plant photosynthesis, discovered by Robert Emerson. The quantum yield of red light (less than 680nm) and far red light (700nm), when shone simultaneously on a plant, is greater than the sum of the yields of the light of the two wavelengths separately. This effect provides evidence for the cooperative interaction of two photosystems in photosynthesis. (18 Nov 1997) |
| cardioesophageal relaxation | Relaxation of the lower oesophageal sphincter which can allow reflux of acidic gastric contents into the lower oesophagus, producing oesophagitis. (05 Mar 2000) |
| relaxation | A state of relative freedom from both anxiety and skeletal muscle tension. (16 Dec 1997) |
| relaxation factor | Substance presumably involved in the return of muscle fibrils to the resting state after nervous stimulation ceases, postulated to act by withdrawing Calcium from myosin-ATPase sites. (05 Mar 2000) |
| relaxation response | An integrated hypothalamic reaction resulting in decreased sympathetic nervous system activity which, physiologically and psychologically, is almost a mirror image of the body's response's to Cannon's emergency theory (flight or fight response); can be self-induced through the use of techniques associated with transcendental meditation, yoga, and biofeedback. See: emergency theory. (05 Mar 2000) |
| relaxation suture | A suture so arranged that it may be loosened if the tension of the wound becomes excessive. (05 Mar 2000) |
| relaxation techniques | The use of muscular relaxation techniques in treatment. (12 Dec 1998) |
| relaxation time | Time taken for a system to return to the resting or ground state or a new equilibrium state following perturbation. Often used in context of receptor systems that have a refractory period after responding and then relax to a competent state. Can be used more precisely to mean the time for a system to change from its original equilibrium value to 1/e of this original value. (18 Nov 1997) |
| muscle relaxation | That phase of a muscle twitch during which a muscle returns to a resting position. (12 Dec 1998) |
| progressive muscle relaxation | A cognitive-behavioural strategy in which muscles are alternately tensed and then relaxed in a systematic fashion. (16 Dec 1997) |