Centrifugation, use

Figure 3 A centrifuge uses a rotating bowl to produce centrifugal force.

Maximum Separative Capaeity and the Separative Effieieney. The separative efficiency of a gas centrifuge used for isotope separation is best defined in terms of separative work. Thus, the separative efficiency E is defined by... 

Solid-Bowl Centrifuge The Bird solid-bowl centrifuge uses powder instead of gravity and can develop centrifugal forces up to 1800 times the force of gravity. It is therefore a unique type in classification practice. 

Dry centrifugals used as primary collectors, followed by final cleaner. 

Under nitrogen, a mixture of 97 (2 eq.), 2,6-dibromo-l-dedocyloxy-4-methylbenzene 98 (1 eq.), and Pd(PPli3)2Cl2 in THF was stirred at reflux for 24 h. Polymer 99 was purified by repetitive precipitation-centrifugation using THF and MeOH. GPC (polystyrene standards) Mn = 1700, PDI = 1.4. 

Separation. The proeess by which the bacterial cells are separated from the culture fluid. Centrifugation using either a batch or continuous flow process is commonly used, but preeipitation of the cells by reducing the pH is an alternative. In the case of vaeeines prepared fiom eells, the fluid is discarded and the cells are resuspended in a saline mixture where vaeeines are made fiom a constituent of the fluid, the cells are discarded. 

Separate complexes by ultra-centrifugation using a SW41 rotor at 35,000 rpm for 2 25 h at 4°. 

If some precipitation occurs, clarify the solution by centrifugation using a microfuge. Remove excess reactant by gel filtration using a desalting resin. 

For estimation of proteins covalently bound to chromatographic matrices hydrolyze the sample for 6 h at 37 ° C in solution D. After centrifugation, use an aliquot for protein determination. 

This protocol illustrates the combination of differential and density gradient centrifugation, using a high-capacity low-speed centrifuge as well as an ultracentrifuge. 

Most laboratories have a standard low-speed centrifuge used for routine sedimentation of relatively heavy particles. The common centrifuge has a maximum speed in the range of 4000 to 5000 rpm, with RCF values up to 3000 X g. These instruments usually operate at room temperature with no means of temperature control of the samples. Two types of rotors, fixed angle and swinging bucket, may be used in the instrument. Centrifuge tubes or bottles that contain 12 or 50 mL of sample are commonly used. Low-speed... 

Special laboratory centrifuges used in analysis and research are described in Refs 15,17,20,22, 24... 

Various centrifuges used in the manuf of NC and expls are described in Ref 1... 

The disk centrifuge is the type of centrifuge used most often for bioseparations. It has the advantage of continuous operation. It consists of a short, wide bowl 8 to 20 in. in diameter that turns on a vertical axis (Figure 10.2b). The closely spaced cone-shaped discs in the bowl decrease the distance that a suspended particle has to be moved to be captured on the surface and increases the collection efficiencies. In operation, feed liquid enters the bowl at the bottom, flows into the channels and upward past the disks. Solid particles are thrown outward and the clear liquid flows toward the center of the bowl and is discharged through an annular slit. The collected solids can be removed intermittently or continuously. 

Cell populations can be enriched using a number of physicochemical methods based on characteristics, such as density, size, and volume. Centrifugation using density gradients is typically applied to isolate populations with similar characteristics. Cells obtained using these methods can be further authenticated using specific antibodies that react to markers on the cell surface, allowing the identification of cell subtypes. 

Ointment Alcuronium Chloride TLC/ HPLC Add 2,2,4-trimethylpentane vortex, add MeOH-H 0 (45 5), mix centrifuge, use lower layer Silica CHClj-acetone (7 1) 350 nm USP 23, p. 41 [5]... 

Proteins with large differences in molecular mass can be separated by rate-zonal centrifugation using a gradient of a dense material such as sucrose. 

The main types of industrial centrifuges used for bioparticle separations are the tubular, the multi-chamber, and the disc centrifuges Figure 11.8). The disc centrifuge may have nozzles to allow continuous exit of the concentrated suspension. The nozzles allow operation in a continuous mode, with Rf > 0. Tubular and multi-chamber centrifuges operate with... 

The cytoplasmic organelles may be separated from each other by differential centrifugation or by density gradient centrifugation using sucrose or one of the commercially available alternatives, e.g. Percoll or Metrizamide. Some alternative approaches are considered by Howell et al. (1989). 

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