Small-angle X-ray scattering experiment

Rossle, M., Panine, P., Urban, V. S., and Riekel, C. (2004). Structural evolution of regenerated silk fibroin under shear Combined wide- and small-angle x-ray scattering experiments using synchrotron radiation. Biopolymers 74, 316-327. Rousseau, M. E., Lefevre, T., Beaulieu, L., Asakura, T., and Pezolet, M. (2004). Study of protein conformation and orientation in silkworm and spider silk fibres using Raman microspectroscopy. Biomacromolecules 5, 2247-2257. 

Figure 8. Model structure of intact CBH I as deduced from the results of small angle X-ray scattering experiments (17). The arrow indicates the proteolytic scission site (papain), dividing the core-protein (left) from the binding domain (right). A, A-domain B, B-domain N, N-terminus C, C-terminus.

However, the results of small-angle X-ray scattering experiments on iron-labelled networks have not entirely confirmed the above results for a given network the product d Q ll3 is not found to be a constant. The reason for this discrepancy is yet unknown. 

Al3+ (ionic radius, 0.54 A) is smaller than Fe3+ but still forms a stable transferrin complex, with binding constants 10125 and 10.13 5 Al3+ is displaced by Fe3+ (144) but the Al2Tf complex is stable enough that it has been shown to bind to cell surface receptors (164). Small-angle X-ray scattering experiments, however, indicate that the Al3+-transferrin complex is conformationally distinct from the diferric... 

Transmission electron microscopy and small-angle X-ray scattering experiments, still at their beginning, corroborate at least qualitatively these findings and interpretations, so that more accurate synthesis-properties relationships may be established soon, despite the complexity of the problem. 

The overall shape of the RAGl zinc-binding dimerization domain is elongated as modelled by a prolate ellipsoid of revolution. Both sedimentation velocity and small-angle x-ray scattering experiments yielded axial ratios consistent with an extended molecule in solution for the ZDD dimer. 

FIG. 21 Constitution formula for poly(p-phenylene). The fully aromatic backbone exhibits an excellent chemical stability and has a persistence length of approximately 20 nm. The degree of polymerization used in the studies in Refs. 34, 46 was located between 20 and 40, so that the contour length equals approximately one persistence length at most. The dominant contribution to the signal in small-angle x-ray scattering experiments stems from the iodine ions, since the excess electron density of the backbone is very low. 

A similar fitting procedure has been applied to the measured data from small-angle x-ray scattering experiments on systems 3 and 4 see also Ref. 

TABLE 4 Fit Evaluation of Small-Angle X-Ray Scattering Experiments on Systems 3 and 4... 

An X ray pattern of such a sample shows that there is no crystal-lin phase left. The ionic clusters have a diameter of around 20 A as measured by small angle X ray scattering experiments. Most of the water left in this sample is trapped inside these cluster. 

The principle of a small angle X-ray scattering experiment using synchrotron radiation (SR) is illustrated in Fig. 2. The optical system selects X-rays with a wavelength of 0.15 nm and a narrow band-width (A V ) 5 10 . This beam is focused on the detector with an adequate cross section at the sample position. The incident beam intensity I, which follows the slow decay of the current in the storage... 

Wang ZG, Hsiao BS, Srinivas S, Brown GM, Tsou AH, Cheng SZD, Stein RS (2001) Isothermal Crystallization and Melting of Isotactic Polypropylene Analyzed by Time- and Temperature-dependent Small-angle X-ray Scattering Experiments Polymer 42 7561-7566. 

In a second study, they evaluated the interfacial thickness of twopoly(isoprene-b-methyl methacrylate) block copolymers (Pl-PMMA) using the same approach. Small-angle X-ray scattering experiments showed that films of the mixed diblock copolymers have a lamellar morphology with a spacing that varies with composition from 24 to 26 nm. Fluorescence decay profiles from these films were analyzed in terms of an energy transfer model that takes into account the distribution of junctions across the interface and calculated an interface thickness of 1.6 + — 0.1 nm. This value was independent of the acceptor/donor ratio (i.e., the acceptor concentration) in the films. 

Fig. 10.4. Illustration of excess signals and their subtraction in typical small angle x-ray scattering experiment. The filled squares and open circles are SANS spectra of

Marliere C, Despetis F, Etienne P et al (2001) Very large-scale structures in sintered silica aerogels as evidenced by atomic force microscopy and ultra-small angle X-ray scattering experiments. Journal of Non-Crystalline Solids 285 148-153... 

Though polymer P18/19 (G4) does not show any liquid crystallinity, it nevertheless forms supramolecular structures in the bulk (77). This was concluded from x-ray diffraction patterns obtained from Si plates coated with this polymer and monomer (18), respectively. A series of Bragg peaks for the polymer showed the existence of an ordered structure. Based on MD calculations and additional small-angle x-ray scattering experiments, this structure was proposed to be body-centered cubic. 

Schmidtke, J. Strobl, G Thum-Albrecht, T. A four-state scheme for treating polymer crystaUization and melting suggested by calorimetric and small angle X-ray scattering experiments on syndiotactic polypropylene. Macromolecules 1997, 30, 5804—5821. 

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