ultracentrifuge

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ultracentrifuge

 [ul″trah-sen´trĭ-fūj]
the centrifuge used in ultracentrifugation.
Miller-Keane Encyclopedia and Dictionary of Medicine, Nursing, and Allied Health, Seventh Edition. © 2003 by Saunders, an imprint of Elsevier, Inc. All rights reserved.

ul·tra·cen·tri·fuge

(ŭl'tră-sen'tri-fyūj),
A high-speed centrifuge (up to 100,000 rpm) by means of which large molecules, for example, of protein or nucleic acids, are caused to sediment at practicable rates; used for determinations of molecular weights, separation of large molecules, criteria of homogeneity of large molecules, conformational studies, etc.
Farlex Partner Medical Dictionary © Farlex 2012

ultracentrifuge

(ŭl′trə-sĕn′trə-fyo͞oj′)
n.
A high-velocity centrifuge used in the separation of colloidal or submicroscopic particles.

ul′tra·cen·trif′u·gal (-trĭf′yə-gəl, -trĭf′ə-gəl) adj.
ul′tra·cen·trif′u·gal·ly adv.
ul′tra·cen′tri·fu·ga′tion (-fyo͝o-gā′shən) n.
The American Heritage® Medical Dictionary Copyright © 2007, 2004 by Houghton Mifflin Company. Published by Houghton Mifflin Company. All rights reserved.

ul·tra·cen·tri·fuge

(ŭl'tră-sen'tri-fyūj)
A high-speed centrifuge by means of which large molecules (e.g., of protein or nucleic acids) are caused to sediment at practicable rates.
Medical Dictionary for the Health Professions and Nursing © Farlex 2012

ultracentrifuge

A device for rotating small containers at extremely high speed so as to expose the liquid contents to powerful centrifugal force, of the order of 100,000 g. Ultracentrifuges are used to separate particles of molecular size and determine molecular weights.
Collins Dictionary of Medicine © Robert M. Youngson 2004, 2005

ultracentrifuge

a machine capable of spinning a rotor at speeds of up to 50 000 revolutions per minute, producing up to 500 000 g forces. The high speeds enable the separation of tiny particles, which are identified by the rate at which they move down the centrifuge tube. The unit of rate is called the Svedberg (S), after the inventor of the ultracentrifuge. Thus RIBOSOMES are found to consist of two subunits after ultracentrifugation, called 30S and 50S. See also DENSITY-GRADIENT CENTRIFUGATION, DIFFERENTIAL CENTRIFUGATION, MICROSOMAL FRACTION.
Collins Dictionary of Biology, 3rd ed. © W. G. Hale, V. A. Saunders, J. P. Margham 2005

ul·tra·cen·tri·fuge

(ŭl'tră-sen'tri-fyūzh)
A high-speed centrifuge by means of which large molecules sediment at practicable rates.
Medical Dictionary for the Dental Professions © Farlex 2012
References in periodicals archive ?
Because the LDL-cholesterol concentration is determined by subtracting the HDL-cholesterol concentration, derived from the nonultracentrifuged serum, from the cholesterol concentration in the bottom fraction, the ultracentrifugation conditions for the modified methods were optimized to provide cholesterol concentrations in the bottom fraction equivalent to that of the 5-mL method.
To evaluate the intrarun precision as well as the extent of remixing of the top and bottom fractions on standing after ultracentrifugation, 17 replicates were analyzed in a single ultracentrifugation run by each of the three [beta]-quantification methods.
Finally, specimens that are excessively hypertriglyceridemic are problematic for the measurement of LDL and HDL by both the homogeneous and traditional methods unless the triglyceride-rich VLDL is removed by ultracentrifugation. Therefore, the [beta]-quantification method is still relevant despite the arrival of new homogeneous assays for LDL- and HDL-cholesterol, particularly in basic and clinical research, where rapid turnaround time and small specimen size often are critical.
Factors that increased specimen throughput were (a) use of a gravimetrically calibrated manual pipette for the introduction of specimen into the ultracentrifuge tube; (b) use of open-top ultracentrifuge tubes that do not require sealing before ultracentrifugation; (c) use of a calibrated CentriTube Slicer; (d) use of a set of dedicated, preset, and gravimetrically calibrated manual pipettes for the reconstitution of the top and bottom fractions; and (e) placement of reconstituted fractions directly into analyzer-ready tubes or cups rather than volumetric flasks.