| 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) |
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| rotational axis | An imaginary line around which a removable partial denture tends to rotate. Synonym: rotational axis. (05 Mar 2000) |
| rotational nystagmus | Jerky nystagmus arising from stimulation of the labyrinth by rotation of the head around any axis and induced by change of motion. (05 Mar 2000) |
| rotational transform | <radiobiology> \iota = 2PI/q) Due to the combination of applied toroidal field and induced poloidal field, the magnetic field lines wind helically around the torus (and on most flux surfaces they fill the surface ergodically). The rotational transform is a measure of this helicity, and is defined as the average angle the field line shifts in the poloidal direction per complete circuit in the toroidal direction. The quantity q = 2\pi / \iota is known as the "safety factor'' because of its role in stability theory. A magnetic field configuration is said to posses rotational transform if the lines of force, after one complete circuit around the configuration (for example, a torus) do not simply close exactly on themselves, but are instead rotated through some angle about the magnetic axies. (13 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) |
| 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) |
| spin-lattice relaxation | In nuclear magnetic resonance, the return of the magnetic dipoles of the hydrogen nuclei (magnetization vector) to equilibrium parallel to the magnetic field, after they have been flipped 90 |
| spin-spin relaxation | In nuclear magnetic resonance, the return of the magnetic dipoles of the hydrogen nuclei (magnetization vector) to equilibrium parallel to the magnetic field, after they have been flipped 90 |
| isometric relaxation | Decrease in tension of a muscle while the length remains constant due to fixation of the ends. (05 Mar 2000) |