| shear stress | The force acting in shear flow expressed per unit area; units in the CGS system: dynes/cm2. (05 Mar 2000) |
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| stress | 1. Forcibly exerted influence, pressure. In dentistry, the pressure of the upper teeth against the lower in mastication. 2. The sum of the biological reactions to any adverse stimulus, physical, mental or emotional, internal or external, that tends to disturb the organisms homeostasis, should these compensating reactions be inadequate or inappropriate, they may lead to disorders. The term is also used to refer to the stimuli that elicit the reactions. (18 Nov 1997) |
| stress-bearing area | Surfaces of structures that resist forces, strains, or pressures brought upon them during function. (05 Mar 2000) |
| stress breaker | A device that relieves the abutment teeth, to which a fixed or removable partial denture is attached, of all or part of the forces generated by occlusal function. (05 Mar 2000) |
| stress disorders, posttraumatic | Anxiety disorders manifested by the development of characteristic symptoms following a psychologically traumatic event that is outside the normal range of usual human experience. Symptoms include re-experiencing the traumatic event and numbing of responsiveness to or reduced involvement with the external world. (12 Dec 1998) |
| stress echocardiogram | <investigation> An echocardiogram that is performed after a period of physical exertion. Chemical stimulation of the heart (to mimic exertion) is used in some cases where physical activity is not possible. In some cases, exertion may manifest a cardiac abnormality not obvious during echocardiography in the resting heart. (27 Sep 1997) |
| stress echocardiography | Echocardiographic monitoring of a circulatory challenge, usually exercise. Transesophageal echocardiography, recording of the echocardiogram from a transducer swallowed by the patient to predetermined distances in the oesophagus and stomach. Transthoracic echocardiography, the standard echocardiography recorded from echocardiographic "windows" on the precordium. Two-dimensional echocardiography, echocardiography in which an image is reconstructed from the echoes stimulated and detected by a linear array or moving transducers. Synonym: B-mode echocardiography, cross-sectional echocardiography. (05 Mar 2000) |
| stress fibre | <physiology> Long bundles of microfilaments made up of actin subunits. They are involved in the attachment of cultured cells to a substratum, the determination of cell shape and may be involved in cellular mobility. They are found in most cells and have been shown to be contractile, have a periodicity reminiscent of the sarcomere and are anchored at one end to a focal adhesion, although sometimes between two focal adhesions. (17 Jul 2002) |
| stress fracture | <orthopaedics, radiology> A hairline or microscopic break in the bone that is not demonstrable with conventional X-rays. Symptoms include a dull aching pain with tenderness at the site. Symptoms often increase with activity and diminish with rest. Nuclear bone scanning will reliably demonstrate stress fractures where conventional radiographs often fail. Although they may occur in most any location, they are most common in the tibia, fibula and metatarsal bones. (27 Sep 1997) |
| stress immunity | Insusceptibility or resistance to the effects of emotional strain. (05 Mar 2000) |
| stress induced protein | <molecular biology> Alternative and preferable name for heat-shock proteins of eukaryotic cells, which emphasises that the same small group of proteins is stimulated both by heat and various other stresses. (18 Nov 1997) |
| stress, mechanical | A purely physical condition which exists within any material because of strain or deformation by external forces or by non-uniform thermal expansion; expressed quantitatively in units of force per unit area. (12 Dec 1998) |
| stress, psychological | Stress wherein emotional factors predominate. (12 Dec 1998) |
| stress reaction | An acute emotional reaction related to extreme environmental stress. Synonym: acute situational reaction. (05 Mar 2000) |
| stress riser | A mechanical defect, such as a hole, in bone or other materials that concentrates stress in the area. (05 Mar 2000) |