Elutriation centrifugation

Light scattering Automatic image analyzing microscopy or SEM Gas adsorption Electrical resistivity Sedimentation Elutriation Centrifugation Impaction X-ray diffraction line broadening... 

Beckman Elutriation Method. The Beckman elutriation method uses a chamber designed so that the centrifugal effect of the radial inward fluid flow is constant (Fig. 3). The separation chambers are made of transparent epoxy resin which faciUtates observation of the movements of the cell boundary in strobe light illumination. This enables detection of the radius at which the cells are separating. When a mixture of cells, eg, mononuclear white cells, enters the chamber, separation can be achieved by fine tuning centrifuge speed and inward fluid flow to the specific cell group. This is a laboratory method suitable for relatively small numbers of cells. Chambers are available in sizes to handle 2-3 x 10 , 1 2 x 10 , and 1 x 10 ° cells. The Beckman chambers can be appHed to collect mononuclear cells from bone marrow aspirates. 

Glassification. Classification (2,12,26,28) or elutriation processes separate particles by the differences in how they settle in a Hquid or moving gas stream. Classification can be used to eliminate fine or coarse particles, or to produce a narrow particle size distribution powder. Classification by sedimentation iavolves particle settling in a Hquid for a predetermined time to achieve the desired particle size and size distribution or cut. Below - 10 fim, where interparticle forces can be significant, gravitational-induced separation becomes inefficient, and cyclone and centrifugation techniques must be used. Classification also separates particles by density and shape. Raw material separation by differential sedimentation is commonly used in mineral processiag. 

A continuous centrifugal bioreactor, in which cells are fluidized in balance with centrifugal forces, has been designed to allow high density cell cultivation and superior aeration without elutriation of the suspended cells (van Wie et al., 1991). Reactor performance was hampered by elutriation of biomass by evolved gas in an anaerobic fermentation, indicating that it may not be suitable in its present state for three-phase fermentations. Immobilization of the cells on denser particles may overcome this problem. 

Isolation of Cells for Transport Studies Use of nonequilibrium thermodynamics in the analysis of transport general flow-force relationships and the linear domain, 171, 397 cell isolation techniques use of enzymes and chelators, 171, 444 cell separation by gradient centrifugation methods, 171, 462 cell separation by elutriation major and minor cell types from complex tissues,... 

For porewater extraction, whole wet sediment is centrifuged at 17,000 x g for 20 min. An elutriate (aqueous extract) is obtained by shaking the wet sediment sample in an aerobic milieu for 24 h. Soluble substances are extracted under such conditions. The elution process is performed with the original wet sediment and the... 

The early work on centrifugal elutriation has been reviewed by Pretlow and Pretlow (1979). 

In some steady-state methods of separation (isoelectric focusing, density-gradient centrifugation, and sometimes elutriation), component zones approach a stationary configuration centered about different points in space. Separation occurs by virtue of the different steady-state positions of the various solutes. In other systems (field-flow fractionation, zone refining,... 

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