Coefficients and molecular weights

Fio. 3. Sedimentation coefficient and molecular weight as functions of pH. (A) Sedimentation coefficients as a function of pH. (O) s°0 w values were determined for samples adjusted from neutral pH to each pH value. The concentrations were 72 mg/ml, except at pH 5 and pH 4, where they were 4j0 mg/ml in 0.01 Af tris-0.01 Af sodium acetate. (0) s°0 w values were determined for samples adjusted from neutral pH to the given pH. Concentrations were 0.62 mg/ml in 0.1 Af NaCl-0.01 Af tris-0.01 M sodium acetate. ( ) s° w values were determined for samples prepared at pH 2, then dialyzed at the appropriate pH. Concentrations were 0.62 mg/ml in 0.1 M NaCl-0.01 Af tris-0.01 M sodium acetate. (O) Determinations with Schlieren optics all other determinations were made with the use of ultraviolet optics with the photoelectric scanner. (B) Weight average molecular weight as a function of pH. (0) M values were determined for samples adjusted from neutral pH to each pH indicated, by dialysis, 0.62 mg/ml, in 0.1 M NaCl-0.01 M tris-0.01 M sodium acetate. (O) Mw values were determined for samples prepared at pH 2, then dialyzed at the appropriate pH, 0.62 mg/ml in 0.1 M NaCl-0.01 Af tris-0.01 Af sodium acetate. 

Levin, V.A. 1980. Relationship of octanol/water partition coefficient and molecular weight to rat brain capillary permeability. J Med Chem 23 682. 

Coefficients and Molecular Weights. Where proportions are known, coefficients can be used (Equation 20). This indicates five moles of P2... 

Mathematical models relate skin permeability of exogenous molecules to physicochemical parameters of the permeant (octanol/water partition coefficients and molecular weight [a surrogate marker of molecular size]). Similar models for animal and human skin relate normalized equations of best-fit regressions based on ... 

Table 11.6 Diffusion coefficients and molecular weights of peptides and proteins"...

Density gradient ultra-centrifugation can be used to determine the buoyant density of DNA and quadruplexes. Sedimentation experiments can also be used to measure sedimentation coefficients and molecular weights. Bead modeling on atomic-level model structures can be used to calculate theoretical hydrodynamic properties of DNA the structures. The calculated hydrodynamic properties (translational diffusion, sedimentation coefficients (S) and correlation times) in conjunction with the program HYDROPRO has been used to help differentiate between known or inferred structural conformations measured by analytical ultra-centrifugation. 

The purpose of our study was a rheological evaluation of the effect of composition on the properties of ABS resins in the molten state. Steady-state viscosity was determined over a wide range of temperatures and shear rates. The shear modulus in the molten state was determined by measurement of the diameter of the extrudate. ABS resins in the molten state behaved as an amorphous homophase polymer. The effect of the elastomer phase on the viscoelastic properties which characterize the behavior of the continuous matrix, i.e. monomer friction coefficient and molecular weight between entanglements (Me), was calculated by the application of the molecular theories. The significance of these properties in heterophase systems is discussed. 

TABLE 1. Relationship Between Sedimentation Coefficients and Molecular Weight of Complexes and their D-RNA. 

Sedimentation Coefficients and Molecular Weights of Some rRNA Species... 

Also evident from the above two plots should be the fact that frictional coefficient and molecular weight are very related functions. Thus any study to find out the relationship between s and M. in fact, becomes a study to find out the relationsffip between frlction d coefficient and molecular weight. Such studies become especially Important since many of the researchers prefer to characterize a macromolecule by just finding out its sedimentation coefficient and not its molecular weight. This is done because it is simpler to determine the former. The sedimentation coefficient is then supposed to reflect the molecular weight of the macromolecule. 

Levin VA (1980) Relationship of octanol/water partition coefficient and molecular weight to rat brain capillary permeability. J Med Chem 23 682-684 Link G, Athias P, Grynberg A, Pinson A, Hershko C (1989) Effect of iron loading on transmembrane potential, contraction, and automaticity of rat ventricular muscle cells in culture. J Lab Clin Med 113 103-111 Link G, Pinson A, Hershko C (1993) Iron loading of cultured cardiac myocytes modifies sarcolemmal structure and increases lysosomal fragility. J Lab Clin Med 121 127-134... 

A plot of selectivity versus critical temperature for these gases is presented in Figure 30.7. The plot shows that the permeabilities of the molecules increase as the critical temperatures increase. This indicates that the solubility is the controlling mechanism for mixed-matrix membrane selectivity. However, for fighter gases such as H2 and N2 the permeability decreases as the molecular weight increases. The inverse relationship between the diffusion coefficient and molecular weight implies the importance of molecular diffusion coefficients. 

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