Synchrotron X-Ray Scattering Study of Chromatin Condensation Induced by Monovalent Salt: Analysis of the Small-Angle Scattering Data

Small-angle X-ray scattering has established itself as a common technique in structural biology research. Here, two novel Java applications to aid modelling of three-dimensional macromolecular structures based on small-angle scattering data are described.MolScatis an application that computes small-angle scattering intensities from user-provided three-dimensional models. The program can fit the theoretical scattering intensities to experimental X-ray scattering data.SAFIRis a program for interactive rigid-body modelling into low-resolution shapes restored from small-angle scattering data. The program has been designed with an emphasis on ease of use and intuitive handling. An embedded version ofMolScatis used to enable quick evaluation of the fit between the model and experimental scattering data.SAFIRalso provides options to refine macromolecular complexes with optional user-specified restraints against scattering data by means of a Monte Carlo approach.

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Hierarchically organized materials with ordered mesopores: adsorption isotherm and adsorption-induced deformation from small-angle scattering

Physical Chemistry Chemical Physics ◽

10.1039/d0cp01026j ◽

2020 ◽

Vol 22 (22) ◽

pp. 12713-12723 ◽

Cited By ~ 1

Author(s):

Lukas Ludescher ◽

Roland Morak ◽

Stephan Braxmeier ◽

Florian Putz ◽

Nicola Hüsing ◽

...

Keyword(s):

Adsorption Isotherm ◽

Small Angle ◽

Small Angle Scattering ◽

Scattering Data ◽

X Ray ◽

Hierarchical Porosity ◽

X Ray Scattering ◽

Angle Scattering ◽

Apparent Strain ◽

Ordered Mesopores

Apparent strain artifacts resulting from the evaluation of small-angle X-ray scattering data superimpose the actual adsorption induced deformation in silica with hierarchical porosity. These artifacts can be corrected for by detailed modelling.

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Nanostructure of a-Si:H and Related Materials by Small-Angle X-Ray Scattering

MRS Proceedings ◽

10.1557/proc-377-251 ◽

1995 ◽

Vol 377 ◽

Cited By ~ 84

Author(s):

D. L. Williamson

Keyword(s):

Small Angle ◽

Detailed Comparison ◽

Small Angle Scattering ◽

Atomic Scale ◽

X Ray ◽

X Ray Scattering ◽

Current State ◽

Angle Scattering ◽

Wide Range ◽

Ray Scattering

ABSTRACTThe use of small-angle x-ray scattering to examine nanostructural features of a-Si:H and the related alloys a-SiGe:H and a-SiC:H will be reviewed. A wide range of H, Ge, and C compositions has been investigated. The films examined came from several film- and device-making groups and represent current state-of-the-art solar cell material or attempts to develop improved and more stable material. A detailed comparison of the three classes of materials reveals dramatic differences in nanostructure. The diffuse component of the small-angle scattering, not recognized or discussed in previous small-angle scattering experiments on these materials by other groups, is shown to contain potentially valuable information on the atomic-scale structure.

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Interpretation of small-angle X-ray scattering patterns of crystalline triglyceride nanoparticles in dispersion

Journal of Applied Crystallography ◽

10.1107/s0021889807044378 ◽

2007 ◽

Vol 40 (6) ◽

pp. 1008-1018 ◽

Cited By ~ 13

Author(s):

T. Unruh

Keyword(s):

Small Angle ◽

Simulation Analysis ◽

Aqueous Dispersion ◽

Small Angle Scattering ◽

X Rays ◽

X Ray ◽

Scattering Model ◽

X Ray Scattering ◽

Angle Scattering ◽

Ray Scattering

Triglyceride nanocrystals in aqueous dispersion produced by high-pressure melt homogenization exhibit platelet-like shapes and clear but broadened Bragg reflections in the small-angle scattering regime. Because the particle thickness, the thickness of the stabilizer layer, the length scale of the crystalline structure of the nanoparticles and often the interparticle distances are of the same order of magnitude, the scattering of these structures mutually interferes. This leads to complicated small-angle scattering patterns which exhibit a lot of features, but it is not straightforward to discover the contained information on the structure of the system. In this contribution, a scattering model for such systems will be described, which is based on the kinematic scattering theory of X-rays. Using this scattering model an X-ray powder pattern simulation analysis is introduced to gain information on tripalmitin nanosuspensions which have been investigated by synchrotron small-angle X-ray scattering. It will be demonstrated that the results of this method provide a consistent description of all structural details mentioned above. In particular, information on the extension and the molecular packing density of the stabilizer layers can be achieved because these layers exhibit a comparatively large scattering contrast.

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Small-Angle X-ray Scattering at the ESRF High-Brilliance Beamline

Journal of Applied Crystallography ◽

10.1107/s0021889897001647 ◽

1997 ◽

Vol 30 (5) ◽

pp. 867-871 ◽

Cited By ~ 22

Author(s):

P. Bösecke ◽

O. Diat

Keyword(s):

Small Angle ◽

Small Angle Scattering ◽

Optical Systems ◽

Photon Flux ◽

X Rays ◽

Time Resolved ◽

X Ray ◽

X Ray Scattering ◽

Angle Scattering ◽

Ray Scattering

The high-brilliance beamline (BL4/ID2) at the European Synchrotron Radiation Facility (ESRF) in Grenoble has been constructed with the emphasis on time-resolved small-angle X-ray scattering and macromolecular crystallography. It has been open to users for two years. The beamline has opened up new areas in small-angle scattering research, facilitating (a) small-angle crystallography on structures with unit cells of several hundredths of nanometres, (b) overlap with the light scattering range for the study of optical systems, (c) high photon flux for time-resolved experiments and (d) a high spatial coherence allowing submicrometre imaging with X-rays. The set-up and the detector system of the small-angle scattering station are presented. A method for obtaining absolute scattering intensities is described. The parasitic background at the station is discussed in terms of absolute scattering intensities.

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Performance and First Results of the ELETTRA High-Flux Beamline for Small-Angle X-ray Scattering

Journal of Applied Crystallography ◽

10.1107/s0021889897001593 ◽

1997 ◽

Vol 30 (5) ◽

pp. 872-876 ◽

Cited By ~ 93

Author(s):

H. Amenitsch ◽

S. Bernstorff ◽

M. Kriechbaum ◽

D. Lombardo ◽

H. Mio ◽

...

Keyword(s):

Small Angle ◽

Small Angle Scattering ◽

Design Parameters ◽

High Flux ◽

Time Resolved ◽

X Ray ◽

X Ray Scattering ◽

Angle Scattering ◽

Scattering Measurements ◽

Ray Scattering

A new beamline for small-angle X-ray scattering (SAXS) has recently been constructed and is presently under final commissioning at the 2 GeV storage ring ELETTRA. It has been designed specifically for time-resolved studies of non-crystalline and fibrous materials and has been optimized for small-angle scattering measurements. The beamline operates with a SAXS resolution between 10 and about 1400 Å in d spacing (at 8 keV) and has been optimized with respect to high flux at the sample [of the order of 1013 photons s−1 for 8 keV photons (2 GeV, 400 mA)]. Soon it will be possible to perform simultaneously wide-angle diffraction measurements in the d-spacing range 1.2–8 Å (at 8 keV). In order to allow time-resolved (resolution ~1 ms) small-angle scattering measurements, a high-power 57-pole wiggler is used as the beamline source. From its beam, one of three discrete energies, 5.4, 8 and 16 keV, can be selected with a double-crystal monochromator, which contains three pairs of asymmetrically cut plane Si(111) crystals. Downstream, the beam is focused horizontally and vertically by a toroidal mirror. Commissioning tests of this new SAXS beamline showed that all design parameters have been realized.

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A new method for evaluating the size of plate-like precipitates by small-angle scattering

Journal of Applied Crystallography ◽

10.1107/s0021889812039891 ◽

2012 ◽

Vol 45 (6) ◽

pp. 1208-1218 ◽

Cited By ~ 35

Author(s):

Frédéric De Geuser ◽

Françoise Bley ◽

Alexis Deschamps

Keyword(s):

Small Angle ◽

Volume Fraction ◽

Small Angle Scattering ◽

Number Density ◽

X Ray ◽

X Ray Scattering ◽

Angle Scattering ◽

Ewald Sphere ◽

Scattering Study

A methodology is presented for extracting the thickness and length of plate-like precipitates from streaking that appears in the small-angle scattering pattern of moderately textured polycrystalline samples. This methodology builds upon existing work on single crystals but is extended to polycrystals through a modeling of the streaking misalignment distribution. It is also shown that it is essential to take into account the Ewald sphere curvature. The protocol is applied to anin situsmall-angle X-ray scattering study of the transition between θ′ andT1in an Al–Li–Cu system, where the contributions of both phases are well separated, and the size, volume fraction and number density are monitored.

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Absolute intensity calibration for carbon-edge soft X-ray scattering

Journal of Synchrotron Radiation ◽

10.1107/s1600577520011066 ◽

2020 ◽

Vol 27 (6) ◽

pp. 1601-1608

Author(s):

Thomas Ferron ◽

Devin Grabner ◽

Terry McAfee ◽

Brian Collins

Keyword(s):

Small Angle ◽

Absolute Intensity ◽

Small Angle Scattering ◽

Interfacial Structure ◽

Thin Polymer Film ◽

X Ray ◽

X Ray Scattering ◽

Angle Scattering ◽

Intensity Calibration ◽

Ray Scattering

Resonant soft X-ray scattering (RSOXS) has become a premier probe to study complex three-dimensional nanostructures in soft matter through combining the robust structural characterization of small-angle scattering with the chemical sensitivity of spectroscopy. This technique borrows many of its analysis methods from alternative small-angle scattering measurements that utilize contrast variation, but thus far RSOXS has been unable to reliably achieve an absolute scattering intensity required for quantitative analysis of domain compositions, volume fraction, or interfacial structure. Here, a novel technique to calibrate RSOXS to an absolute intensity at the carbon absorption edge is introduced. It is shown that the X-ray fluorescence from a thin polymer film can be utilized as an angle-independent scattering standard. Verification of absolute intensity is then accomplished through measuring the Flory–Huggins interaction parameter in a phase-mixed polymer melt. The necessary steps for users to reproduce this intensity calibration in their own experiments to improve the scientific output from RSOXS measurements are discussed.

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