| SSD | shaded surface display; single saturating dose; Social Security disability; source-skin distance; so... |
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| CTH | Chronic Tension Headache |
| (A-a)DN2 | alveolo-arterial nitrogen tension difference |
| AADO2, (a-A) DO2 | arterio-alveolar oxygen tension difference |
| A-a O2 | alveolo-arterial oxygen tension |
| tension headache | <neurology> A benign form of headache that results from the painful spasm (muscle tightness) and inflammation of muscles of the head and neck. Tension headache is one of the most common forms of headache. Spasm and contraction of the head and neck muscles may occur in response to fatigue, overuse, eye strain, excessive smoking, stress, anxiety or depression. Sleeping in an abnormal position or prolonged work involving immobilisation of the neck in one position (typing, computers, etc.) are considered common triggers. Exercising and stretching the muscles of the head and neck can reduce the occurrence of muscle tension headaches. (13 Jan 1998) |
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| tension, intraocular | The pressure within the eye. (12 Dec 1998) |
| tension, intravenous | The pressure of the blood within a vein, the venous pressure. (12 Dec 1998) |
| tension pneumothorax | A variety of spontaneous pneumothorax in which air enters the pleural cavity and is trapped during expiration; intrathoracic pressure builds to values higher than atmospheric pressure, compresses the lung, and may displace the mediastinum and its structures toward the opposite side, with consequent disadvantageous effects on blood flow. Synonym: pressure pneumothorax, valvular pneumothorax. (05 Mar 2000) |
| tension suture | <surgery> A heavy reinforcing suture placed deep within the muscles and fasciae of the abdominal wall to relieve tension on the primary suture line and thus obviate postoperative wound disruption. Synonym: tension suture. (05 Mar 2000) |
| tissue tension | A theoretical condition of equilibrium or balance between the tissues and cells whereby overaction of any part is restrained by the pull of the mass. (05 Mar 2000) |
| low tension glaucoma | Optic nerve atrophy and excavation with typical field defects of glaucoma but without abnormal increase in intraocular pressure. (05 Mar 2000) |
| Abbe theory of image formation | <optics, physics> Abbe's theory is based on the fact that a non-self-luminous particle, which is illuminated by an extraneous source, gives rise to diffracted light rays, in addition to the dioptric pencil. He stated that to form a good microscopical image as many of the diffracted rays as possible should be intercepted by the objective. With closely ruled lines, his theory is easily demonstrated by observing the back lens of the objective, for here the diffracted rays can be observed directly if the aperture diaphragm is closed. It can be shown that, when the illumination is arranged to exclude the diffracted images, resolution is lost. (11 Mar 1998) |
| Altmann's theory | A theory that protoplasm consists of granular particles (called bioblasts) that are clustered and enclosed in indifferent matter. (05 Mar 2000) |
| Arrhenius-Madsen theory | That the reaction of an antigen with its antibody is a reversible reaction, the equilibrium being determined according to the law of mass action by the concentrations of the reacting substances. (05 Mar 2000) |
| atomic theory | That chemical compounds are formed by the union of atoms in certain definite proportions; in its modern form, first advanced in 1803 by John Dalton. (05 Mar 2000) |
| Baeyer's theory | That carbon bonds are set at fixed angles (109 |
| balance theory | In social psychology, a theory which assumes that steady and unsteady states can be specified for cognitive units, such as an individual and his or her attitudes or acts, and that such units tend to seek steady states (balance); e.g., balance exists when both parts of a unit are evaluated the same, but disequilibrium arises when both parts are not evaluated the same, which causes either cognitive reevaluation of the parts or their segregation. See: cognitive dissonance theory, consistency principle. (05 Mar 2000) |
| beta-oxidation-condensation theory | <biochemistry> That the two carbon fragments split from the fatty acid molecule by beta-oxidation are converted to acetic acid and then condensed to acetoacetic acid. (05 Mar 2000) |
| Bohr's theory | That spectrum lines are produced 1) by the quantised emission of radiant energy when electrons drop from an orbit of a higher to one of a lower energy level, or 2) by absorption of radiation when an electron rises from a lower to a higher energy level. (05 Mar 2000) |