| centre of rotation | A point or line around which all other points in a body move. See: axis. (05 Mar 2000) |
|---|
| rotation | <dentistry> A movement in which the tooth turned along the long axis of the tooth. (08 Jan 1998) |
|---|---|
| rotation flap | A pedicle flap that is rotated from the donor site to an adjacent recipient area, usually as a direct flap. (05 Mar 2000) |
| rotation therapy | Teletherapy in which a desirable radiation dose distribution is achieved by rotating the patient or machine about an axis passing through the centre of the tumour. (05 Mar 2000) |
| short rotation energy plantation | Plantings established and managed under short-rotation intensive culture practices. (05 Dec 1998) |
| short rotation intensive culture | Intensive management and harvesting at 2 to 10 year intervals of cycles of specially selected fast- growing hardwood species for the purpose of producing wood as an energy feedstock. (05 Dec 1998) |
| intestinal rotation | See: malrotation. Molecular rotation, one hundredth of the product of the specific rotation of an optically active compound and its molecular weight. Optical rotation, the change in the plane of polarization of polarised light of a given wavelength upon passing through optically active substances; measured in terms of specific rotation by polarimetry, an important tool in chemical structural work, especially on carbohydrates. Specific optical rotation ([a]), the arc through which the plane of polarised light is rotated by 1 gram of a substance per milliliter of water when the length of the light path through the solution is 1 decimeter, typically using light corresponding to the D line of sodium. (05 Mar 2000) |
| active centre | The part of a macromolecule at which a substrate or ligand, upon binding, produces biological activity; for an enzyme, this is the catalytic centre, the site on an enzyme that catalyses the reaction. (05 Mar 2000) |
| anospinal centre | The centre in the spinal cord that controls the contraction of the anal sphincter. (05 Mar 2000) |
| asymmetric centre | <chemistry> Same as a chiral centre, a tetrahedral carbon atom that bears four different substituents. (09 Jan 1998) |
| Broca's centre | The posterior part of the inferior frontal gyrus of the left or dominant hemisphere, corresponding approximately to Brodmann's area 44; Broca identified this region as an essential component of the motor mechanisms governing articulated speech. Synonym: Broca's area, Broca's field, motor speech centre. (05 Mar 2000) |
| Budge's centre | The preganglionic motor neurons in the first thoracic segment of the spinal cord which give rise to the sympathetic innervation of the dilator muscle of the eye's pupil. Synonym: Budge's centre. (05 Mar 2000) |
| vasomotor centre | Diffuse area of the reticular formation in the lateral medulla containing neurons that control vascular tone; consists of separate vasodepressor and vasopressor areas. (05 Mar 2000) |
| reaction centre | <plant biology> The site in the chloroplast that receives the energy trapped by chlorophyll and accessory pigments and initiates the electron transfer process. A photosynthetic complex containing chlorophyll (or bacteriochlorophyll) and other components, within which occurs the initial electron transfer reactions of photophosphorylation. (09 Oct 1997) |
| germinal centre | Areas within lymph nodes where B lymphocytes rapidly divide. (09 Oct 1997) |
| germinal centre kinase | <enzyme> A human ste20 homolog; mw 97 kD; has been sequenced Registry number: EC 2.7.10.- Synonym: germinal centre kinase gck, gc kinase, bl44 gene product (26 Jun 1999) |