| SPT | secretin-pancreazymin [test]; single patch technique; sleep period time; spectrin; station pull-thro... |
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| CFSTI | Clearinghouse for Federal Scientific and Technical Information |
| COSATI | Committee on Scientific and Technical Information |
| CSTI | Clearinghouse for Scientific and Technical Information |
| ICSTI | International Council for Scientific and Technical Information |
| spleen focus-forming viruses | Murine leukaemia viruses that are replication-defective and rapidly transforming. The envelope gene plays an essential role in initiating erythroleukaemia, manifested by splenic foci, splenomegaly, and polycythemia. Spleen focus-forming viruses are generated by recombination with other viral types including friend p (polycythemia), friend a (anaemia), rauscher, and cas (from wild mice at lake casita, california). (12 Dec 1998) |
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| natural focus of infection | An ecosystem in which an infectious agent normally persists in nature; e.g., yellow fever virus in a jungle monkey-Haemagogus mosquito ecosystem. (05 Mar 2000) |
| depth of focus | <microscopy> The depth or thickness of the image space that is simultaneously in acceptable focus. The range of distances between a lens and image plane (target in the video pickup device) for which the image formed by the lens at a given setting is clearly focused. With a high-numerical aperture microscope objective, the depth of field is very shallow, but the depth of focus can be quite deep and reach several millimetres. (05 Aug 1998) |
| focus | Group of (frequently neoplastic) cells, identifiable by distinctive morphology or histology. (18 Nov 1997) |
| focus-forming assay | <investigation> A lab technique used to find out if a particular piece of DNA contains oncogenes (genes which are associated with cancer). This is done by putting the DNA into animal cells which normally show contact inhibition, or which stop growing when they come into physical contact with other cells or reach a certain density in the culture. If the cells lose contact inhibition and form areas of densely-packed cells (called foci) after receiving the DNA, it means that the DNA did contain oncogenes. (05 Jan 1997) |
| focus-forming unit | A measurement of the concentration of live virus in a given amount of fluid. This is measured by spreading a known amount of the fluid over a layer of cultured cells which are infected by the virus, then counting the number of areas in the culture which look infected. (09 Oct 1997) |
| focus groups | A method of data collection and a qualitative research tool in which a small group of individuals are brought together and allowed to interact in a discussion of their opinions about topics, issues, or questions. (12 Dec 1998) |
| focus, principal | <physics> The point at which a lens focuses an axial object point. Synonymous with focal point. (05 Aug 1998) |
| Friend spleen focus forming virus | <virology> Defective virus found in certain strains of Friend virus, detected by its ability to form foci in spleens of mice and believed to be responsible in those strains for the production of a leukaemia associated with polycythaemia rather than anaemia. (18 Nov 1997) |
| airbrasive technique | A method of grinding, cutting tooth structure, or roughening the natural tooth surface or the surface of a restoration, by means of a device utilizing a gas-impelled jet of fine Al203 particles which, after striking the tooth, are removed by an aspirator. See: microetching technique. (05 Mar 2000) |
| air-gap technique | Chest radiography performed using a space between the subject and film instead of a grid to absorb scattered radiation; usually requires a target-film distance of 10 feet. (05 Mar 2000) |
| aseptic technique | <procedure> A method used by microbiologists and clinicians to keep cultures, sterile instruments and media, and people free of microbial contamination. (09 Oct 1997) |
| atrial-well technique | An obsolete semi-closed surgical technique for repairing atrial septal defects and other cardiac abnormalities. (05 Mar 2000) |
| Barcroft-Warburg technique | An apparatus for measuring the oxygen consumption of incubated tissue slices by manometric measurement of changes in gas pressure produced by oxygen absorption in an enclosed flask. Synonym: Barcroft-Warburg apparatus. (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) |