| ecosystem function | The collective intraspecific and interspecific interactions of the biota, such as primary and secondary production and mutualistic relationships. The interactions between organisms and the physical environment, such as nutrient cycling, soil development, water budgeting, and flammability. (09 Oct 1997) |
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| function | The special, normal or proper physiologic activity of an organ or part. Origin: L. Functio, from fungi = to do (18 Nov 1997) |
| function corrector | A removable orthodontic appliance utilizing oral and facial muscle forces to move teeth and possibly change the relationship of the dental arches. (05 Mar 2000) |
| line spread function | A measure of the ability of a system to form sharp images; in radiology, determined by measuring the spatial density distribution on film of the X-ray image of a narrow slit in a dense metal, such as uranium; from this can be calculated the modulation transfer function. (05 Mar 2000) |
| liver function test | <investigation> A test that measures the blood serum level of several enzymes produced by the liver. An elevated liver function test is a sign of possible liver damage. Examples include: prothrombin time, PTT, serum glutamic oxaloacetic transaminase, serum glutamic pyruvic transaminase, gamma glutamyl transpeptidase, alkaline phosphatase and serum albumin. (14 Oct 1997) |
| lymphocyte function associated antigen | A member of the integrin family that is expressed on all leukocytes and binds to ICAM-1 and ICAM-2 on a variety of cells. (05 Mar 2000) |
| lymphocyte function-associated antigen-1 | A heterodimer molecule widely expressed on cells of haematopoietic origin. Cd11a antigen comprises the alpha chain and the CD18 antigen (antigens, CD18) the beta chain. Lfa-1 is a major receptor of T-cells, B-cells, and granulocytes. It mediates the leukocyte adhesion reactions underlying cytolytic conjugate formation, helper T-cell interactions, and antibody-dependent killing by natural killer cells and granulocytes. Intracellular adhesion molecule-1 (icam-1) has been defined as a ligand for lfa-1. (12 Dec 1998) |
| radial | <botany> Of or pertaining to a radius or ray; consisting of, or like, radii or rays; radiated; as, the radial artery. Radial symmetry. <biology> See Symmetry. Origin: Cf. F. Radial. See Radius. Source: Websters Dictionary (01 Mar 1998) |
| radial acceleration | The centripetal acceleration of a particle or vehicle moving along a curved path at a constant velocity; e.g., turning a curve in an automobile, pulling out of a dive, or performing a loop manoeuvre in an aircraft. In aviation, acceleration varies directly with the square of the air speed and inversely with the radius of the turn (a = V2/r, where V is air speed and r is radius of turn). (05 Mar 2000) |
| radial aplasia-thrombocytopenia syndrome | <syndrome> Aplasia (absence) of the radius (the long bone on the thumb-side of the forearm) and thrombocytopenia (low blood platelets) are key features characterizing this syndrome. There is phocomelia (flipper-limb) with the thumbs always present. The fibula (the smaller bone in the lower leg) is often absent. The risk of bleeding from too few platelets is high in early infancy but lessens with age. The condition is inherited in an autosomal recessive trait with one gene (on a non-sex chromosome) coming from each parent to the child affected with the disease. Alternative names include thrombocytopenia-absent radius syndrome, tar syndrome, and tetraphocomelia-thrombocytopenia syndrome. (12 Dec 1998) |
| radial artery | <anatomy, artery> The direct continuation of the brachial trunk, originating at the bifurcation of the brachial artery opposite the neck of the radius. Its branches may be divided into three groups corresponding to the three regions in which the vessel is situated, the forearm, wrist, and hand. (12 Dec 1998) |
| radial border of forearm | An imaginary line running along the outermost extent of the forearm separating anterior and posterior surfaces laterally. Synonym: margo lateralis antebrachii, margo radialis antebrachii, radial border of forearm. (05 Mar 2000) |
| radial bursa | <anatomy> The synovial sheath that envelops the tendon of the flexor pollicis longus in its course through the carpal canal; it is continuous with the digital sheath of the thumb, the two generally being considered as one sheath. Synonym: vagina tendinis musculi flexoris pollicis longi, radial bursa. (05 Mar 2000) |
| radial clubhand | Clubhand with angular deviation towards radial side of limb. See: manus valga. (05 Mar 2000) |
| radial collateral artery | <anatomy, artery> The anterior terminal branch of the profunda brachii, anastomosing with the radial recurrent, forming part of the articular network of the elbow. Synonym: arteria collateralis radialis. (05 Mar 2000) |