| PR | by way of the rectum [Lat. per rectum]; far point [of accommodation] [Lat. punctum remotum]; palindr... |
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| DASD | Direct Access Storage Device = RAM |
| DC | 1) Direct Current 2) Diffusion Capacity |
| DFA | Direct Fluorescent Antibody |
| AC-DC, ac/dc | alternating current or direct current |
| direct transfusion | Transfusion of blood from the donor to the receptor, either through a tube connecting their blood or by suturing the vessels together. Synonym: immediate transfusion. (05 Mar 2000) |
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| direct vision | Vision stimulated by an object imaged on the fovea centralis. Synonym: direct vision. (05 Mar 2000) |
| direct vision spectroscope | <instrument> A spectroscope consisting of a single tube containing a series of prisms; one end of the tube is placed in as close contact as possible with the substance to be examined while the observer places his eye at the opposite end; it can be used to make a spectroscopic examination of the blood in vivo, as in the ear lobe or web of the thumb. (05 Mar 2000) |
| direct zoonosis | A zoonosis transmitted between animal and humans from an infected to a susceptible host by contact, by airborne droplets or droplet nuclei, or by some vehicle of transmission; the agent requires a single vertebrate host for completion of its life cycle and does not develop or show significant change during transmission; may include anthropozoonoses (rabies), zooanthroponoses (amoebiasis), and amphixenoses (certain streptococcoses). (05 Mar 2000) |
| fluorescent antibody technique, direct | A form of fluorescent antibody technique utilizing a fluorochrome conjugated to an antibody, which is added directly to a tissue or cell suspension for the detection of a specific antigen. (12 Dec 1998) |
| lateral direct veins | One or more veins running a subependymal course in a coronal plane over the thalamus, terminating in the internal cerebral vein. Synonym: lateral direct veins, surface thalamic veins. (05 Mar 2000) |
| alternating light test | Test to detect a relative afferent defect in one eye by watching pupillary movements. With the patient fixing in the distance, the light is held on each eye for about a second, and quickly moved to the other eye. Assuming no defect of the innervation to the iris sphincter in one eye (which would produce an anisocoria in light), the eye with the weaker light response has a relative afferent pupillary defect. This asymmetry of pupillomotor input can be estimated by holding neutral density filters in front of the better eye until the pupillary responses of the two eyes are balanced. Synonym: swinging light test. (05 Mar 2000) |
| Begg light wire differential force technique | An orthodontic appliance utilizing small gauge labial wires with expansion and contraction loops formed into it and attached to bands fitted to individual teeth; sometimes called Begg light wire differential force technique. (05 Mar 2000) |
| gene rearrangement, b-lymphocyte, light chain | Ordered rearrangement of b-lymphocyte variable gene regions coding for the kappa or lambda light chains, thereby contributing to antibody diversity. It occurs during the second stage of differentiation of the immature b-lymphocyte. (12 Dec 1998) |
| ray, light | <microscopy> The term applied to the lines perpendicular to the wavefronts of waves of light to indicate their direction of travel in an isotropic medium. Note the wave normal and the ray do not coincide in isotropic media. (05 Aug 1998) |
| reflected light | Light directed backward from a mirror. (05 Mar 2000) |
| refracted light | Bent rays of light changed in passage from one transparent medium to another of unequal density. See: refraction. (05 Mar 2000) |
| visible light | <physics> Electromagnetic radiation with wavelengths between 400 nanometres and 750 nanometres. Electromagnetic radiation within this range can be detected by the human eye. Colours depend on the wavelength lengths, a short wavelength (the 400 nm side) looks blue and a long wavelength (the 750 nm side) looks red. (09 Oct 1997) |
| metals, light | Metals with low specific gravity, typically smaller than 5, characterised by a single valence (1, 2, or 3), a simple spectrum, strong electromotive force (positive), and colourless compounds. (12 Dec 1998) |
| minimum light | Threshold of visual sensation, the minimal light intensity evoking a visual sensation. Synonym: achromatic threshold, minimum light threshold. (05 Mar 2000) |