scholarly journals Determination of interaction forces between higher plant thylakoids and electron-density-profile evaluation using small-angle X-ray scattering

1985 ◽  
Vol 809 (1) ◽  
pp. 107-116 ◽  
Author(s):  
Kay Diederichs ◽  
Wolfram Welte ◽  
Werner Kreutz
Keyword(s):  
Electron Density ◽  
Density Profile ◽  
Small Angle ◽  
Electron Density Profile ◽  
Higher Plant ◽  
Interaction Forces ◽  
X Ray ◽  
X Ray Scattering ◽  
Ray Scattering

BILMIX: a new approach to restore the size polydispersity and electron density profiles of lipid bilayers from liposomes using small-angle X-ray scattering data

2020 ◽  
Vol 53 (1) ◽  
pp. 236-243
Author(s):  
Petr V. Konarev ◽  
Maxim V. Petoukhov ◽  
Liubov A. Dadinova ◽  
Natalia V. Fedorova ◽  
Pavel E. Volynsky ◽  
...  
Keyword(s):  
Lipid Bilayer ◽  
Electron Density ◽  
Lipid Bilayers ◽  
Density Profile ◽  
Small Angle ◽  
Electron Density Profile ◽  
Scattering Data ◽  
X Ray ◽  
X Ray Scattering ◽  
Ray Scattering

Small-angle X-ray scattering (SAXS) is one of the major tools for the study of model membranes, but interpretation of the scattering data remains non-trivial. Current approaches allow the extraction of some structural parameters and the electron density profile of lipid bilayers. Here it is demonstrated that parametric modelling can be employed to determine the polydispersity of spherical or ellipsoidal vesicles and describe the electron density profile across the lipid bilayer. This approach is implemented in the computer program BILMIX. BILMIX delivers a description of the electron density of a lipid bilayer from SAXS data and simultaneously generates the corresponding size distribution of the unilamellar lipid vesicles.

X-ray Scattering Study of Pike Olfactory Nerve: Intensity of the Axonal Membrane, Solution of the Phase Problem and Electron Density Profile

2004 ◽  
Vol 343 (1) ◽  
pp. 187-197 ◽  
Author(s):  
Vittorio Luzzati ◽  
Patrice Vachette ◽  
Evelyne Benoit ◽  
Gilles Charpentier
Keyword(s):  
Electron Density ◽  
Density Profile ◽  
Olfactory Nerve ◽  
Electron Density Profile ◽  
Phase Problem ◽  
Axonal Membrane ◽  
X Ray ◽  
X Ray Scattering ◽  
Scattering Study ◽  
Ray Scattering

scholarly journals Size and Concentration Determination of Colloidal Nanocrystals by Small-Angle X-Ray Scattering

2018 ◽  
Author(s):  
Jorick Maes ◽  
Nicolo Castro ◽  
Kim De Nolf ◽  
Willem Walravens ◽  
Benjamin Abécassis ◽  
...  
Keyword(s):  
Band Gap ◽  
Small Angle ◽  
Accurate Determination ◽  
Band Gap Energy ◽  
Colloidal Nanocrystals ◽  
X Ray ◽  
Absolute Scale ◽  
X Ray Scattering ◽  
Ray Scattering

<div> <div> <div> <p>The accurate determination of the dimensions of a nano-object is paramount to the de- velopment of nanoscience and technology. Here, we provide procedures for sizing quasi- spherical colloidal nanocrystals (NCs) by means of small-angle x-ray scattering (SAXS). Using PbS NCs as a model system, the protocols outline the extraction of the net NC SAXS pattern by background correction and address the calibration of scattered x-ray intensity to an absolute scale. Different data analysis methods are compared, and we show that they yield nearly identical estimates of the NC diameter in the case of a NC ensemble with a monodisperse and monomodal size distribution. Extending the analysis to PbSe, CdSe </p> </div> </div> <div> <div> <p>and CdS NCs, we provide SAXS calibrated sizing curves, which relate the NC diameter and the NC band-gap energy as determined using absorbance spectroscopy. In compari- son with sizing curves calibrated by means of transmission electron microscopy (TEM), we systematically find that SAXS calibration assigns a larger diameter than TEM calibration to NCs with a given band gap. We attribute this difference to the difficulty of accurately sizing small objects in TEM images. To close, we demonstrate that NC concentrations can be directly extracted from SAXS patterns normalized to an absolute scale, and we show that SAXS-based concentrations agree with concentration estimates based on absorption spectroscopy.</p></div></div></div>

scholarly journals The effect of polydispersity, shape fluctuations and curvature on small unilamellar vesicle small-angle X-ray scattering curves

2021 ◽  
Vol 54 (2) ◽  
pp. 557-568
Author(s):  
Veronica Chappa ◽  
Yuliya Smirnova ◽  
Karlo Komorowski ◽  
Marcus Müller ◽  
Tim Salditt
Keyword(s):  
Lipid Bilayer ◽  
Density Profile ◽  
Small Angle ◽  
Thermal Fluctuations ◽  
Electron Density Profile ◽  
Membrane Asymmetry ◽  
X Ray ◽  
X Ray Scattering ◽  
Vesicle Shape ◽  
Small Unilamellar Vesicles

Small unilamellar vesicles (20–100 nm diameter) are model systems for strongly curved lipid membranes, in particular for cell organelles. Routinely, small-angle X-ray scattering (SAXS) is employed to study their size and electron-density profile (EDP). Current SAXS analysis of small unilamellar vesicles (SUVs) often employs a factorization into the structure factor (vesicle shape) and the form factor (lipid bilayer electron-density profile) and invokes additional idealizations: (i) an effective polydispersity distribution of vesicle radii, (ii) a spherical vesicle shape and (iii) an approximate account of membrane asymmetry, a feature particularly relevant for strongly curved membranes. These idealizations do not account for thermal shape fluctuations and also break down for strong salt- or protein-induced deformations, as well as vesicle adhesion and fusion, which complicate the analysis of the lipid bilayer structure. Presented here are simulations of SAXS curves of SUVs with experimentally relevant size, shape and EDPs of the curved bilayer, inferred from coarse-grained simulations and elasticity considerations, to quantify the effects of size polydispersity, thermal fluctuations of the SUV shape and membrane asymmetry. It is observed that the factorization approximation of the scattering intensity holds even for small vesicle radii (∼30 nm). However, the simulations show that, for very small vesicles, a curvature-induced asymmetry arises in the EDP, with sizeable effects on the SAXS curve. It is also demonstrated that thermal fluctuations in shape and the size polydispersity have distinguishable signatures in the SAXS intensity. Polydispersity gives rise to low-q features, whereas thermal fluctuations predominantly affect the scattering at larger q, related to membrane bending rigidity. Finally, it is shown that simulation of fluctuating vesicle ensembles can be used for analysis of experimental SAXS curves.

Analysis of Nanopowders by Small-Angle X-Ray Scattering Method’s

2012 ◽  
Vol 7 (4) ◽  
pp. 107-116
Author(s):  
Sergey Bardakhanov ◽  
Ludmila Vikulina ◽  
Vladimir Lysenko ◽  
Andrey Nomoev ◽  
Sergey Poluyanov ◽  
...  
Keyword(s):  
Distribution Function ◽  
Size Distribution ◽  
Small Angle ◽  
Electron Accelerator ◽  
Size Distribution Function ◽  
X Ray ◽  
X Ray Scattering ◽  
Ray Scattering

The possibility of application of small-angle X-ray scattering (SAXS) for nanopowders analysis was studied. The research for eight silica powders (including four powders obtained by the authors with help of electron accelerator) was conducted. The possibility of application of small angle X-ray scattering for determination of size distribution function of nanoparticles was shown

Determination of the Microstructure of Wet and Dry Brown Coal by Small-Angle X-Ray Scattering

1984 ◽  
pp. 95-108 ◽  
Author(s):  
M. SETEK ◽  
I. K. SNOOK ◽  
H. K. WAGENFELD
Keyword(s):  
Brown Coal ◽  
Small Angle ◽  
X Ray ◽  
X Ray Scattering ◽  
Ray Scattering
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