Role of boron on grain sizes and magnetic correlation lengths in recording media as determined by soft x-ray scattering

2002 ◽  
Vol 80 (7) ◽  
pp. 1234-1236 ◽  
Author(s):  
Olav Hellwig ◽  
D. T. Margulies ◽  
B. Lengsfield ◽  
Eric E. Fullerton ◽  
J. B. Kortright
Keyword(s):  
Recording Media ◽  
Correlation Lengths ◽  
X Ray ◽  
Magnetic Correlation ◽  
Grain Sizes ◽  
X Ray Scattering ◽  
Ray Scattering

X-ray-scattering study of the two magnetic correlation lengths in uranium antimonide

1996 ◽  
Vol 54 (21) ◽  
pp. 15234-15237 ◽  
Author(s):  
S. C. Perry ◽  
W. J. Nuttall ◽  
W. G. Stirling ◽  
G. H. Lander ◽  
O. Vogt
Keyword(s):  
Correlation Lengths ◽  
X Ray ◽  
Magnetic Correlation ◽  
X Ray Scattering ◽  
Scattering Study ◽  
Ray Scattering

scholarly journals Resonant Inelastic X-ray Scattering on Ferrous and Ferric Bis-imidazole Porphyrin and Cytochromec: Nature and Role of the Axial Methionine–Fe Bond

2014 ◽  
Vol 136 (52) ◽  
pp. 18087-18099 ◽  
Author(s):  
Thomas Kroll ◽  
Ryan G. Hadt ◽  
Samuel A. Wilson ◽  
Marcus Lundberg ◽  
James J. Yan ◽  
...  
Keyword(s):  
X Ray ◽  
X Ray Scattering ◽  
Ray Scattering

scholarly journals Prominent role of oxygen in the multiferroicity ofDyMnO3andTbMnO3: A resonant soft x-ray scattering spectroscopy study

2016 ◽  
Vol 94 (3) ◽  
Author(s):  
S. W. Huang ◽  
J. M. Lee ◽  
Horng-Tay Jeng ◽  
YuCheng Shao ◽  
L. Andrew Wray ◽  
...  
Keyword(s):  
Spectroscopy Study ◽  
X Ray ◽  
X Ray Scattering ◽  
Ray Scattering

scholarly journals The Role of Intersubunit Interactions for the Stabilization of the T State ofEscherichia coliAspartate Transcarbamoylase

2002 ◽  
Vol 277 (51) ◽  
pp. 49755-49760 ◽  
Author(s):  
Robin S. Chan ◽  
Jessica B. Sakash ◽  
Christine P. Macol ◽  
Jay M. West ◽  
Hiro Tsuruta ◽  
...  
Keyword(s):  
Small Angle ◽  
Structural State ◽  
Aspartate Transcarbamoylase ◽  
Wild Type ◽  
X Ray ◽  
X Ray Scattering ◽  
Intersubunit Interactions ◽  
T State ◽  
Ray Scattering

Homotropic cooperativity inEscherichia coliaspartate transcarbamoylase results from the substrate-induced transition from the T to the R state. These two alternate states are stabilized by a series of interdomain and intersubunit interactions. The salt link between Lys-143 of the regulatory chain and Asp-236 of the catalytic chain is only observed in the T state. When Asp-236 is replaced by alanine the resulting enzyme exhibits full activity, enhanced affinity for aspartate, no cooperativity, and no heterotropic interactions. These characteristics are consistent with an enzyme locked in the functional R state. Using small angle x-ray scattering, the structural consequences of the D236A mutant were characterized. The unliganded D236A holoenzyme appears to be in a new structural state that is neither T, R, nor a mixture of T and R states. The structure of the native D236A holoenzyme is similar to that previously reported for another mutant holoenzyme (E239Q) that also lacks intersubunit interactions. A hybrid version of aspartate transcarbamoylase in which one catalytic subunit was wild-type and the other had the D236A mutation was also investigated. The hybrid holoenzyme, with three of the six possible interactions involving Asp-236, exhibited homotropic cooperativity, and heterotropic interactions consistent with an enzyme with both T and R functional states. Small angle x-ray scattering analysis of the unligated hybrid indicated that the enzyme was in a new structural state more similar to the T than to the R state of the wild-type enzyme. These data suggest that three of the six intersubunit interactions involving D236A are sufficient to stabilize a T-like state of the enzyme and allow for an allosteric transition.

Small-Angle X-Ray Scattering for the Discerning Macromolecular Crystallographer

2014 ◽  
Vol 67 (12) ◽  
pp. 1786 ◽  
Author(s):  
Lachlan W. Casey ◽  
Alan E. Mark ◽  
Bostjan Kobe
Keyword(s):  
Structural Biology ◽  
Small Angle ◽  
Significant Risk ◽  
Macromolecular Crystallography ◽  
Saxs Data ◽  
X Ray ◽  
X Ray Scattering ◽  
Ray Scattering

The role of small-angle X-ray scattering (SAXS) in structural biology is now well established, and its usefulness in combination with macromolecular crystallography is clear. However, the highly averaged SAXS data present a significant risk of over-interpretation to the unwary practitioner, and it can be challenging to frame SAXS results in a manner that maximises the reliability of the conclusions drawn. In this review, a series of recent examples are used to illustrate both the challenges for interpretation and approaches through which these can be overcome.

scholarly journals The role of the ionic liquid C6C1ImTFSI in the sol–gel synthesis of silica studied using in situ SAXS and Raman spectroscopy

2015 ◽  
Vol 17 (15) ◽  
pp. 9841-9848 ◽  
Author(s):  
Moheb Nayeri ◽  
Kim Nygård ◽  
Maths Karlsson ◽  
Manuel Maréchal ◽  
Manfred Burghammer ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Ionic Liquid ◽  
Sol Gel ◽  
Chemical Changes ◽  
X Ray ◽  
X Ray Scattering ◽  
Sol Gel Synthesis ◽  
Ray Scattering

Structural and chemical changes during the sol–gel synthesis of silica using an ionic liquid are investigatedin situand simultaneously by X-ray scattering and μ-Raman spectroscopy.

The Structural Role of Gangliosides: Insights from X-ray Scattering on Model Membranes

2020 ◽  
Vol 27 (38) ◽  
pp. 6548-6570
Author(s):  
Konstantin Andreev
Keyword(s):  
Cholera Toxin ◽  
Molecular Mechanisms ◽  
Hexagonal Lattice ◽  
Langmuir Monolayers ◽  
Biologically Active ◽  
Adequate Model ◽  
X Ray ◽  
X Ray Scattering ◽  
Ray Scattering

Background: Gangliosides are an essential component of eukaryotic plasma membranes implicated in multiple physiological processes. Little is known about molecular mechanisms underlying the distribution and functions of membrane gangliosides. The overwhelmingly complex organization of glycocalyx impedes the structural analysis on cell surface and the interplay between the lipid components. Advanced X-ray analytical tools applicable to studying biological interfaces call for the simplistic models that mimic ganglioside-enriched cellular membranes. Objective: To summarize the mechanistic evidences of ganglioside interactions with lipid environment and biologically active ligands using high-resolution synchrotron X-ray scattering. Methods: A comprehensive review of studies published over the last decade was done to discuss recent accomplishments and future trends. Results: Langmuir monolayers represent an adequate model system to assess the effect of gangliosides on membrane structure. Grazing incidence X-ray diffraction reveals a condensation effect by gangliosides on zwitterionic phospholipids with the cooperative packing of sialo- and phosphate groups. In turn, the arrangement of negatively charged lipids in ganglioside mixture remains unchanged due to the stretched conformation of carbohydrate moieties. Upon interaction with biological ligands, such as cholera toxin and galectins, the ganglioside redistribution within the ordered regions of monolayer follows distinct mechanistic patterns. The cholera toxin pentamer attached to the oligosaccharide core induces local transition from oblique to the hexagonal lattice resulting in phase coexistence. The incorporation of the A subunit responsible for endocytosis is further promoted by the acidic environment characteristic for endosomal space. X-ray reflectivity shows in-plane orientation of galectin dimers with the spatial mismatch between the lectin binding sites and ganglioside carbohydrates to perturb ceramide alkyl chains. Recent data also demonstrate sialic acid groups to be potential targets for novel peptide mimicking anticancer therapeutics. Conclusion: Coupled with surface X-ray scattering, the membrane mimetic approach allows for better understanding the biological role of gangliosides and their potential applications.

scholarly journals Defects and Polytypism in SiC: The Role of Diffuse X-Ray Scattering

2010 ◽  
Author(s):  
A. Boulle ◽  
D. Dompoint ◽  
I. Galben-Sandulache ◽  
D. Chaussende ◽  
Gabriel Ferro ◽  
...  
Keyword(s):  
X Ray ◽  
X Ray Scattering ◽  
Ray Scattering
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