Centrifugation study

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... 

It might be noted that sedimentation equilibrium is approached very slowly however, techniques that permit equilibrium conditions to be estimated from preequilibrium measurements have been developed by W. J. Archibald. Equations (86) and (87) predict a linear semilogarithmic plot of c versus x or x2 for gravitational and centrifugal studies, respectively. The slope of such a plot is proportional to the mass of the particles involved. Remember that monodispersity was assumed in the derivation of these equations. If this condition is not met for an experimental system, the plot just described will not be linear. If each particle size present is at equilibrium, however, each component will follow the equations and the experimental plot will be the summation of several straight lines. Under certain conditions these may be resolved to give information about the polydispersity of the system. In any event, nonlinearity implies polydispersity once true equilibrium is reached. 

Figure 22 Binding curves for EB with BAZrP (0.008% phosphate), (a) Binding curve obtained from the absorption titration experiments. The difference between absorbance at 478 nm, due to the free form, and 600 nm, due to the bound form, is calculated as delta absorbance (Y axis), (b) Curve constructed from the centrifugation studies in which the amount of bound EB is determined by separating the bound probe from the free probe by centrifugation. The inflection point, which corresponds to the transition from the bound form to the free form, is almost the same in both the cases. (From Ref. 55. Copyright 1996 Elsevier Publications.)...

In surfactant solutions, these molecules tend to remain in the hydrophobic domains. Interaction between the dyes and the polar head groups of the surfactants prevents aggregation of these dyes in the a-ZrP galleries. Surfactant-dye and matrix-dye interactions align the chromophores with the charge centers closer to the a-ZrP surface, and the hydrophobic ends are buried in the surfactant hydrocarbon chains. The binding of the dyes to the surfactant-a-ZrP matrix is confirmed from powder x-ray diffraction studies as well as from centrifugation studies [69],... 

CENTRIFUGATION STUDY OF HUMIC WATER COAGULATION BY BROWNIAN MOTION... 

When used properly, ultracentrifugation continues to be our major means of determining molecular weight values for humic substances using sedimentation velocity and other techniques. Indeed, centrifugation studies with humic substances have usually centered upon molecular weight measurements. 

In any centrifugation study with humic substances the suppression of intermolecular charge repulsion by the addition of electrolyte is essential (Cameron et al., 1972b Hayes and Swift, 1978). Any ultracentrifugation studies, analytical or preparative, where this has not been property done should be disregarded. 

X-ray, circular dichroism, and centrifuge studies have demonstrated that most mammalian and fish insulins form zinc insulin hexamers similar to those of porcine insulin (Blundell et al, 1972 Blundell and Wood, 1975), with the exception of hagfish insulin, which produces only dimers (Cutfield et al, 1974 Peterson et al, 1974), and guinea pig (Zimmerman et al, 1972), casiragua (Horuk et al, 1979), and porcupine (Horuk et al, 1980) insulins, which exist only as monomers. A complete structural analysis of hagfish insulin dimers shows that, unlike porcine insulin, the two molecules of the dimer in the crystals are exactly equivalent and resemble molecule II of the asymmetric dimer of porcine insulin. This is similar to the structure of porcine insulin in solution as indicated by circular dichroism studies (Wood et al, 1975 Strickland and Mercola, 1976). 

Freeze-thaw cycles Centrifugation studies Heating-oooling studies Evaluate the phase separation and effect of temperature variation on SNEDDS... 

Madabhushi, S. P. G., Zeng, X. (1993). An analysis of the seismic behaviour of quay walls. In K. Arulanandan R.F. Scott (Ed.), Proceedings Verification of Liquefaction Analyses by Centrifuge studies, (VELACS), (Vol. 2), Davis, California. 

Spindle Mechanical Properties. How does the spindle respond to the mitotic forces so that force directionality is controlled and orderly chromosome motion results Artificial forces have been used to study chromosome attachment to the spindle. Especially informative are the centrifugation studies of Schrader (1934), Shimamura (1940), and Yamamoto (1964), and the micromanipulation experiments of Carlson (1952). Recent micromanipulation results (Nicklas and Staehly, 1967) add some details to the earlier observations and confirm them during normal prometaphase and anaphase motion. Artificial forces sufficient to stretch the chromosome cause little or no increase in the distance from the pole to the kinetochore, but there is much less resistance to lateral or poleward displacement. The spindle as a whole behaves in micromanipulation and during isolation as a single body it is a mechanical unit independent of the rest of the cell (reviewed by Mazia, 1961). The simplest, and the classic, interpretation attributes these mechanical properties to individual spindle fibers in order to account for the... 

In the kidney the enzyme wa.s demonstrated in the proximal convoluted tubule, concentrated at the basal pole of the cells and in portions of the renal glomerulus. Deane (1944) reported that the basophilic bodies in the hepatic cells of white mice are usually grouped about the nucleus and has equated these bodies with the microsomal fraction of differential centrifugation studies. Since most investigators have shown that G-6-Pase is associated with the microsomal fraction of liver cells (Table III), the histochemical distribution of the enzyme, as reported by Chiquoine, is consistent with Deane s description of the distribution of the microsome material. 

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