| 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) |
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| air hunger | Extremely deep ventilation such as occurs in patients with acidosis attempting to increase ventilation of alveoli and exhale more carbon dioxide. See: Kussmaul respiration. (05 Mar 2000) |
| air lift fermenter | <apparatus> A fermenter in which circulation of the culture medium and aeration is achieved by injection of air into some lower part of the fermenter. Usually not suitable for animal cell production. Related to gas lift systems where an inert gas is used to achieve circulation in anaerobic conditions. This type of of fermenter is well suited for large-scale production of monoclonal antibodies. (13 Nov 1997) |
| air-lock | <microscopy> An intermediate, enclosed chamber of a vacuum or pressure system through which an object may be passed without effectively changing the vacuum or pressure of the main body of the system. Reference here is to the vacuum of all electron microscopes. (05 Aug 1998) |
| air microbiology | The presence of bacteria, viruses, and fungi in the air. This term is not restricted to pathogenic organisms. (12 Dec 1998) |
| air plant | <botany> A plant deriving its sustenance from the air alone; an aerophyte. The "Florida moss" (Tillandsia), many tropical orchids, and most mosses and lichens are air plants. Those which are lodged upon trees, but not parasitic on them, are epiphytes. Source: Websters Dictionary (01 Mar 1998) |
| air pollutants | Substances which pollute the air. (12 Dec 1998) |
| air pollutants, environmental | Air pollutants which affect environmental conditions. (12 Dec 1998) |
| air pollutants, occupational | Air pollutants found in the work area. They are usually produced by the specific nature of the occupation. (12 Dec 1998) |
| air pollutants, radioactive | Pollutants, present in air, which exhibit radioactivity. (12 Dec 1998) |
| air pollution, indoor | The contamination of indoor air. (12 Dec 1998) |
| air pressure | The force per unit area that the air exerts on any surface in contact with it. Primarily used for articles pertaining to air pressure within a closed environment. (12 Dec 1998) |
| air pump | 1. <physics> A kind of pump for exhausting air from a vessel or closed space; also, a pump to condense air of force in into a closed space. 2. <engineering> A pump used to exhaust from a condenser the condensed steam, the water used for condensing, and any commingled air. Source: Websters Dictionary (01 Mar 1998) |
| air quality maintenance area | Specific populated area where air quality is a problem for one or more pollutants (Portland-Vancouver, Salem, Eugene-Springfield, Medford-Ashland). (05 Dec 1998) |
| air sac | <zoology> Thin-walled sacs or spaces which function as a part of the respiratory system in birds, fishes, insects, and mammals. The sacs are filled with air and connected with the air passages of the lungs; an air cell. Source: Websters Dictionary (04 Jul 1999) |