Structure from Light Scattering

Hart, R. W., and E. P. Gray, 1964. Determination of particle structure from light scattering, J. Appl. Phys., 35, 1408-1415. 

Intermediate forms must also exist, and, indeed, structural models of the amylose molecule exhibit considerable flexibility. Evidence for aggregated helices (very stable aggregates of amylose molecules) has been provided by Paschal] and Foster142 from light-scattering measurements on amylose in solvents of varying pH. 

Wyatt, P. J., and D. T. Phillips, 1972. Structure of single bacteria from light scattering, J. Theor. Biol., 37, 493-501. 

In this respect, and to focus attention simply on PMA, the body of data presented by Liquori and coll, seems fairly conclusive. It should also be recalled that it had previously bear concluded from light scattering studies that the heat and entropy of dilution of PMA are negative 16). And this evidence leads Silberberg, Eliassaf and Katchalsky to assiune that there is a "particularly marked build-up of structure (of the solvent) in the solutions of PMA in other words hydrophobic bonding would greatly impose on the physico-chemical properties of this polyacid in dilute aqueous solution. In the system considered, "specific solvent effects thus appear to be extremely relevant. 

Information about the secondary structures (a-helices, /5-sheets, random coil) can be useful for understanding conformation changes of proteins upon the immobilization process. More specifically, circular dichroism (CD) [70] and FT-IR spectroscopy [56, 58, 61, 71-73] have been applied to study the structural characteristics of various proteins adsorbed on mineral surfaces. Kondo and coworkers [70] have studied the modification in a-helix content of proteins adsorbed on ultrafine silica particles with CD and found a decrease upon immobilization. Circular dichroism is not usually used because this technique is applicable only for the study of enzymes immobilized on nano-sized mineral particles due to problems arising from light scattering effects. On the other hand, infrared spectroscopy does not suffer from light scattering perturbations and has thus been used for the study of the conformation of proteins when they are immobilized on solid supports [57, 58]. 

The structure and arrangement of cellulosic chains play an important role in the formation of liquid crystals. At present, neither the conformation of cellulosics nor the solvent bound to the chain in the case of a lyotropic mesophase are known for these liquid-crystalline systems. Nevertheless, these structural features form the basis for a discussion of structural and thermodynamic aspects. Information on cellulosics is available for the two borderline cases next to the LC state, i.e., for the solvent built-in solid state as well as for the pure solid state, obtained by X-ray, NMR, and potential energy analysis on one side, and for the semi-dilute state from light-scattering experiments on the other side. These data have to be evaluated for a discussion of possible structures and models in liquid-crystalline phases. 

The tertiary structure of the macromolecule and its molecular weight can be ascertained from measurements of intrinsic viscosity and diffusion, from ultracentrifugation studies, and from light scattering determinations. These methods can... 

Figure 4.7 Overbased lead octanoate structure. The dynamic micelles (B) have a well-ordered core (C) (deduced from EXAFS) with a diameter of 1 nm (deduced from light scattering and cryo microscopy). Deposited on a carbon support (A), micelles will rearrange during the solvent evaporation and lead to lamellar aggregates (D)...

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