Centrifugation ultra

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

The specific polysaccharide of the dominant O somatic antigen of Shigella dysenteriae has been shown to be electrophoretically and ultra-centrifugally homogeneous, and to possess a molecular weight of 26,000 from sedimentation and diffusion measurements.2601... 

For separation of colloidal particles and for breaking down emulsions, the ultra-centrifuge is used. This operates at speeds up to 30 rpm (1600 Hz) and produces a force of 100,000 times the force of gravity for a continuous liquid flow machine, and as high as 500,000 times for gas phase separation, although these machines are very small. The bowl is usually driven by means of a small air turbine. The ultra-centrifuge is often run either at low pressures or in an atmosphere of hydrogen in order to reduce frictional losses, and a fivefold increase in the maximum speed can be attained by this means. 

Samples of gallbladder bile obtained in this way were analysed for bile acids, phospholipids and cholesterol (from which the cholesterol saturation indices were derived). Biliary bile-acid composition was then measured by HPLC. The vesicles were separated from micelles by sucrose density gradient ultra-centrifugation and the cholesterol microcrystal nucleation time measured as described above. 

The tendency for ferritin to aggregate is shown 135, 136) by its heterogeneity as demonstrated on gel electrophoresis, column chromatography, ultra-centrifugation, and many other techniques. This association is readily reversible. The re-examination of any single ferritin fraction isolated from a mixture will show at least four fractions similar to the original preparation. This association is a function of the protein subunit surface of the molecule. Apoferritin molecules behave in a quite similar fashion 137) the iron core has little if any effect. 

An alternative description of protein-containing RMs was given by Levashov et al. [148] from ultra-centrifugation studies. Water-soluble dyes (picric acid) were used to determine the molecular weights and sedimentation behavior of the non-protein-containing and protein-containing RMs. The proposed model involved two regimes of Wg (i) at low Wg (where the inner reverse micellar diameter was less than the protein diameter), the protein created a new RM around itself such that the volume of the inner cavity of the filled RM was essentially the volume of the solubihzed protein and (ii) at water contents where... 

First, the sample was examined by GPC, for which four columns of styragel of 106,10s, 104 and 103 A nominal pore size were used. The total number of theoretical plates as determined by acetone at a flow rate of 1 ml/min was ca. 26,000. The eluent was tetrahydrofuran. The chromatogram is shown in Figure 9, which indicates two peaks at ca. 21 and 24 counts. The former may be assigned to the tetra-chain, star-draped component, and the latter to the precursor. However, no complete separation of the two peaks was observed. For another comparison, velocity ultra-centrifugation was performed for the sample at 59,780 rpm using a 6-solvent for polystyrene, cyclohexane. The operation temperature was established at 35 °C, the 6-temperature, to minimize the concentration dependence of sedimentation velocity and other effects. A sedimentation pattern taken by UV-absorption is shown in Figure 10. It is seen that the separation of S-A sample into the two components was quite difficult even at a very low polymer concentration, 0.077 g/dl. 

Zippe, The Development of Short Bowl Ultra-Centrifuges , EP-4420-101-60V, Univ of Virginia... 

Figure 1. Apparent micellar weight by equilibrium ultra-centrifugation vs. initial concentration difference...

Some data for the molecular weight of cellulose of various origins determined by ultra-centrifuging cuprammonium solution, are given in Table 35. 

Bowen, T. J. (1970) An Introduction to Ultra-centrifugation, Wiley (Interscience), New York... 

The mixture was sonicated to eliminate aggregates. A polystyrene latex with a broad distribution was obtained from Kodak. This distribution had been characterized previously by electron microscopy, ultra centrifuge and Coulter counter. A monodlsperse, surfactant free, sulfated, polystyrene standard and a mixture of 10 such monodlsperse standards were purchased from Interfaclal Dynamics Corporation. A polyvinyl chloride latex with a broad distribution was donated by B. F. Goodrich. This sample had been characterized by Joyce Loebl disc centrifuge. These samples were diluted to 0.01% solids and sonicated to eliminate aggregates. 

Fig. (17). Gel electrophoresis (A) and sedimentation on density gradient ultra centrifugation (B) °f anti-lactose antibodies and dissociated antibodies. Antibody (Ab), reaction mixture (R), heavy chain (H), light chain (L). ...

Gradients of electric potential and pressure govern the behavior of ionic systems, selective membranes, and ultra-centrifuges. In electrokinetic phenomena, induced dipoles can cause separations, such as dielectrophoresis and magnetophoresis, which may be especially important in specialized separations. Diffusion potential is the interference between diffusion and electric conduction in an anisotropic crystal where heat conduction occurs in one direction caused by a temperature gradient in another direction. 

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