| centrifuge | A laboratory apparatus that separates mixed samples into homogenouscomponent layers by spinning them at high speed. (09 Oct 1997) |
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| centrifugation, zonal | Centrifugation using a rotating chamber of large capacity in which to separate cell organelles by density-gradient centrifugation. (12 Dec 1998) |
| Waldeyer's zonal layer | A longitudinal bundle of thin, unmyelinated and poorly myelinated fibres capping the apex of the posterior horn of the spinal gray matter, composed of posterior root fibres and short association fibres that interconnect neighboring segments of the posterior horn. Synonym: fasciculus dorsolateralis, tractus dorsolateralis, dorsolateral tract, fasciculus marginalis, Lissauer's bundle, Lissauer's column, Lissauer's fasciculus, Lissauer's marginal zone, Lissauer's tract, marginal fasciculus, Spitzka's marginal tract, Spitzka's marginal zone, Waldeyer's tract, Waldeyer's zonal layer. (05 Mar 2000) |
| zonal | Of or pertaining to a zone; having the form of a zone or zones. Zonal equation, a structure characterised by the arrangements of colour, inclusions, etc, of a crystal in parallel or concentric layers, which usually follow the outline of the crystal, and mark the changes that have taken place during its growth. Zonal symmetry. <biology> See the Note under Symmetry. Origin: L. Zonalis. Source: Websters Dictionary (01 Mar 1998) |
| zonal necrosis | Necrosis predominantly affecting or limited to an anatomical zone, especially parts of the hepatic lobules defined according to proximity to either the portal tracts or central (hepatic) veins. (05 Mar 2000) |