| 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) |
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| 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) |
| denture, partial, fixed | A partial denture attached to prepared natural teeth, roots, or implants by cementation. (12 Dec 1998) |
| denture, partial, fixed, resin-bonded | A commonly used prosthesis that results in a strong, permanent restoration. It consists of an electrolytically etched cast-metal retainer that is cemented (bonded), using resins, to adjacent teeth whose enamel was previously acid-treated (acid-etched). This type of bridgework is sometimes referred to as a maryland bridge. (12 Dec 1998) |
| fixed | 1. Securely placed or fastened; settled; established; firm; imovable; unalterable. 2. <chemistry> Stable; non-volatile. <chemistry> Fixed air, the fixed point about which any line of troops wheels. <astronomy> Fixed stars, such stars as always retain nearly the same apparent position and distance with respect to each other, thus distinguished from planets and comets. Source: Websters Dictionary (01 Mar 1998) |
| fixed alkali | Any alkali other than a weakly ionised one, like ammonia. (05 Mar 2000) |
| fixed alkaloid | A nonvolatile alkaloid. (05 Mar 2000) |
| fixed appliance | <dentistry> Any orthodontic component that is cemented or bonded to the teeth. (08 Jan 1998) |
| fixed bridge | A restoration of one or more missing teeth which cannot be readily removed by the patient or dentist; it is permanently attached to natural teeth or roots which furnish the primary support to the appliance. Synonym: bridge. (05 Mar 2000) |
| fixed contracture | Contracture, usually due to fibrosis within the muscle that persists whether the subject is conscious or unconscious. Synonym: fixed contracture. (05 Mar 2000) |
| fixed coupling | Where several premature beats are seen, the interval between each of them and the preceding normal beat is constant. Synonym: constant coupling. Variable coupling, where several extrasystoles are seen, the interval between each of them and the preceding sinus beat varies. (05 Mar 2000) |
| fixed dressing | A dressing stiffened with a substance that produces immobilization when it dries. (05 Mar 2000) |