Low-angle X-ray diffraction, study

One of the methods for describing the liquid state is based on the Radial Distribution Function (RDF). Because the RDF is obtainable from low angle X-ray diffraction study, this method is attractive to both the theorists and experimentalists. Theoretically, the basic step of the method involves calculation of the potential energy, P, by combining p(r) with [Pg.46]

Worthington, C. R. and Blaurock, A. E. (1969). A low-angle x-ray diffraction study of the swelling behavior of peripheral nerve myelin. Biochim. Biophys. Acta 173 427. 

U. Henriksson, E.S. Blackmore, GJ.T. Tiddy, and O. Soderman, Intermediate Liquid Crystalline Phases in the Binary System C16TACL-H20 - An NMR and Low-Angle X-ray Diffraction Study. J. Phys. Chem., 1992, 96, 3894-3902. 

Femandes-Moran, H., and Finean, J. B., 1957, Electron microscope and low-angle X-ray diffraction studies of the nerve myelin sheath, /. Biophys. Biochem. Cytol. 3 725. 

Herbette and co-workers [425-428,445] studied the structures of drugs bound to liposomes using a low-angle X-ray diffraction technique. Although the structural... 

Ronziere, M-C., Berthet-Colominas, C., and Herbage, D. (1987). Comparative structural studies of reconstituted and native type I and type II collagen fibrils by low angle X-ray diffraction. Biochim. Biophys. Acta 916, 381-387. 

One of the tasks of structural biologists studying muscle contraction is to determine the organization and shapes of the myosin head in muscle under different physiological conditions. The technique of low-angle X-ray diffraction has unique advantages in this process, particularly since it can be applied to living muscle, which can be stimulated to produce active force or can be studied under a variety of different steady-state conditions. The main problem with X-ray fiber diffraction, as detailed in Squire and... 

The study by low-angle X-ray diffraction and electron microscopy of concentrated solutions of the copolymers in preferential solvents for polybutadiene (iso-prene, butadiene) or for poly(a-methyl styrene) (styrene, a-methylstyrene, methyl methacrylate, methylethyl ketone) and of copolymers in the dry state obtained by slow evaporation of the solvent from the mesophases have shown the existence of three types of structure hexagonal, lamellar, and inverse hexagonal depending upon the copolymer composition84,85. The factors governing the structural type and the structural parameters are the same as in the case of polystyrene-polybutadiene copolymers85. ... 

The study by low-angle X-ray diffraction of AB and ABA block copolymers of styrene and isoprene has allowed Gallot et al.1S9-166) to demonstrate that the existence of mesomorphic structures is a quite general property of block copolymers this property is related to the incompatibility of the macromolecular chains11 and the presence in the molecule of a crystallizable (e.g. poly(ethylene oxide)) block is not the condition that governs the formation of mesomorphic structures. 

Pedemonte et have studied by low-angle X-ray diffraction and electron microscopy (on ultra-thin sections of the bulk material) a SIS copolymer containing... 

Systems copolymer SEO/diethyl phthalate of different concentration have been studied by DSC and low-angle X-ray diffraction as a function of the crystallization temperature. It has been found that for a fixed concentration the characteristic parameters of the LC structure vary stepwise. For instance, for a diethyl phthalate concentration of 10%, the thickness dB of the PEO layer increases suddenly when the crystallization temperature reaches 19°, 29° and 42 °C and each jump of the dB parameter corresponds to a decrease by one of the average number v of folds of PEO chains265. An example of the phase diagram crystallization temperature/solvent concentration is given in Fig. 36 for the copolymer SEO 4 whose molecular parameters are summarized in Table 8. The degree of crystallinity of the PEO chains increases with both the crystallization temperature and solvent concentration265. ... 

The study by low-angle X-ray diffraction of these mesophases provides X-ray patterns exhibiting a set of sharp lines with Bragg spadngs characteristic of a layered structure. This lamellar structure results from the superposition of plane, parallel, and equidistant sheets each sheet contains two layers one of thickness dA formed by the carbohydrate blocks, the other of thickness dB formed by the polypeptide blocks, there is a partition of the solvent between the two blocks 70% DMSO is localized in the carbohydrate layer284. Furthermore, the polypeptide chains are in a a-helix conformation as is demonstrated by infrared spectroscopy and X-ray diffraction and are oriented perpendicular to the plane of the sheets and assembled in a bidimensional hexagonal lattice as is revealed by X-rays284. ... 

X-ray diffraction and electron microscopy may be i d separately or together. X-ray diffraction was applied at first in Strasbourg to systems copolymer/solvent as a generalization of the study of systems soap/water and both experimental technics and structural interpretation methods were extended to copolymers. Electron microscopy has been very popular in Japan. The Japanese authors have generally studied films obtained by evaporation of a dilute solution of copolymers but, in that case, the structures observed may be influenced by the nature of the solvent and its speed of evaporation Low angle X-ray diffraction and electron microscopy have been systematically applied together to systems copolymer/solvent and to dry copolymers in Orleans and to oriented dry copolymers in BristoF ... 

The study by low-angle X-ray diffraction of AB and ABA block copolymers of styrene and isoprene has allowed Gallot et al. to demonstrate that the... 

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