| compensating curve | The anteroposterior and lateral curvature in the alignment of the occluding surfaces and incisal edges of artificial teeth; used to develop balanced occlusion. (05 Mar 2000) |
|---|---|
| compensating emphysema | Compensatory emphysema, increase in the air capacity of a portion of the lung when another portion is consolidated, shrunken, or unable to perform its respiratory function; the alveoli are distended, but there is no destruction of alveolar walls, and hence, no true emphysema, as this term is now defined. (05 Mar 2000) |
| compensating eyepieces | <microscopy> Those designed for use with objectives such as apochromats in order to correct chromatic aberration. (05 Aug 1998) |
| compensating ocular | An ocular that compensates and corrects for the effects of chromatic aberration in the objective. (05 Mar 2000) |
| absolute filter | <apparatus> A fine-pored, steam-sterilisable filter that is used to trap airborne microorganisms. The filter's pores are about 2 micrometres in diameter, smaller than the particles it is designed to remove. (06 May 1997) |
| bandpass filter | A device that allows a limited range of frequencies to pass. (05 Mar 2000) |
| Berkefeld filter | A bacterial filter used in 1891, made of earth known as Kieselguhr taken from the name of the mine in Hanover, Germany, from which the earth was found. Ground water at this mine had a clear blue colour suggesting the use of the earth as a filter. Origin: Berkefield, name of owner of the mine from which the material to make the filter was taken (05 Mar 2000) |
| bird's nest filter | A wire mesh vena cava filter. (05 Mar 2000) |
| bird's nest ivc filter | <radiology> Introduced 1982; Cook Inc., Bloomington, IN advantages, low profile: 14.5 Fr introducer sheath, low recurrent PE rates (1.1 - 2.7% by clinical history), low IVC thrombosis rates (2.9 - 5.0% by clinical history), placement in large diameter IVCs (not greater than40mm), free-form configuration does not require centreing in IVC disadvantages: stainless steel: ferromagnetic = magnetic susceptibility artifact, more operator dependent, difficult to place in short IVCs (need about 7cm for proper placement), prolapse of filter wires (? clinical significance) see also: indications (12 Dec 1998) |
| vena cava filter | A filter used for interruption of IVC to prevent pulmonary embolism; e.g., Greenfield filter. Synonym: venocaval filter. (05 Mar 2000) |
| vena-tech ivc filter | <radiology> Introduced as LGM (L.G. Medical, France), 1985; FDA aprroval 1991: Vena-Tech, Evanston, IL, 6-leg conical design with 6 stabilizing side bars, biocompatible metal known as Phynox (cobalt,chromium,iron,nickel,moly) Efficacy, recurrent PE: 2-6%, IVC occlusion: 8-24%, migration: 0-12% Advantages, ease of placement, excellent clot trapping efficiency, low profile, lacks ferromagnetic activity: minimal MRI artifacts Disadvantages, incomplete opening (6-19%): decreases clot-trapping efficiency, increased incidence from IJ approach, decreased with rapid deployment, increased IVC thrombosis rates: 8% initial reports; 22-24% on subsequent reports by ultrasound/MRI: 2-19% clinically symptomatic (12 Dec 1998) |
| venocaval filter | A filter used for interruption of IVC to prevent pulmonary embolism; e.g., Greenfield filter. Synonym: venocaval filter. (05 Mar 2000) |
| Rheinberg filter | <equipment> A colour-filter disk to be placed, as a dark field stop would be placed, below the substage condenser. The central circular area, that is filled with one of the two or three colour filters, should safely subtend the objective aperture. The annular quadrants around this are normally contrasting in colour. This is/are the colour shown by the organisms or other specimen detail against the coloured field. The effect is one kind of optical staining. (05 Aug 1998) |
| Greenfield filter | A multistrutted spring-styled filter usually placed in the inferior vena cava to prevent venous emboli from reaching the pulmonary circulation from the lower extremity. (05 Mar 2000) |
| micropore filter | A filter made of a meshwork of cellulose acetate or nitrate and with defined pore size. They can be autoclaved and the smaller pore sizes (0.22m,0.45m) are used for sterilising heat labile materials by filtering out micro organisms. Larger pore size filters are used in setting up Boyden chambers. They are about 150m thick and should be distinguished from Nucleopore filters. Millipore is a trade name for micropore filters. (18 Nov 1997) |