scholarly journals SCryPTA: A web-based platform for analyzing Small-Angle Scattering curves of lyotropic liquid crystals

2019 ◽  
Author(s):  
Raphael Dias de Castro ◽  
Bruna Renata Casadei ◽  
Barbara Vasconcelos Santana ◽  
Mayra Lotierzo ◽  
Natália F. de Oliveira ◽  
...  
Keyword(s):  
Liquid Crystals ◽  
Small Angle ◽  
Hexagonal Phase ◽  
Small Angle Scattering ◽  
Lyotropic Liquid Crystals ◽  
Crystal Phase ◽  
Scattering Data ◽  
Crystallographic Structure ◽  
Physical Parameters ◽  
Angle Scattering

ABSTRACTSmall angle X-ray scattering (SAXS) is a powerful technique for the characterization of systems with highly ordered structures, such as liquid crystals and self-assembly systems. In the field of nanotechnology and nanomedicine, SAXS can be used to characterize the crystallographic properties of the crystal phase of lyotropic systems and nanoparticles with internal crystal phase, such as cubosomes, hexosomes and multi-lamellar vesicles. In this work, we introduce a new web platform named SCryPTA: Small Angle Scattering Crystallographic Peak Treatment and Analysis, capable of reading SAXS data and providing a comprehensive visualization of the scattering curve along with the calculation of important physical parameters, such as the lattice parameter of the crystal structure, the lipidic bilayer width, among others. Cubic, hexagonal and multilamellar scattering data had their crystallographic structure characterized in SCryPTA. So far, four different cubic structures, (Pn3m (Q224), Fd3m (Q227), Im3m (Q229), Ia3d (Q230)), the hexagonal phase and also multi-lamellar vesicle systems are described in the platform. We believe that SCryPTA may help researchers from several fields, since it has a user-friendly interface. The platform is available at: www.if.usp.br/scrypta.

scholarly journals 2017 publication guidelines for structural modelling of small-angle scattering data from biomolecules in solution: an update

2017 ◽  
Vol 73 (9) ◽  
pp. 710-728 ◽  
Author(s):  
Jill Trewhella ◽  
Anthony P. Duff ◽  
Dominique Durand ◽  
Frank Gabel ◽  
J. Mitchell Guss ◽  
...  
Keyword(s):  
Small Angle ◽  
Task Force ◽  
Data Bank ◽  
Small Angle Scattering ◽  
Scattering Data ◽  
Quality Data ◽  
Angle Scattering ◽  
Publication Guidelines ◽  
Guidelines And Recommendations

In 2012, preliminary guidelines were published addressing sample quality, data acquisition and reduction, presentation of scattering data and validation, and modelling for biomolecular small-angle scattering (SAS) experiments. Biomolecular SAS has since continued to grow and authors have increasingly adopted the preliminary guidelines. In parallel, integrative/hybrid determination of biomolecular structures is a rapidly growing field that is expanding the scope of structural biology. For SAS to contribute maximally to this field, it is essential to ensure open access to the information required for evaluation of the quality of SAS samples and data, as well as the validity of SAS-based structural models. To this end, the preliminary guidelines for data presentation in a publication are reviewed and updated, and the deposition of data and associated models in a public archive is recommended. These guidelines and recommendations have been prepared in consultation with the members of the International Union of Crystallography (IUCr) Small-Angle Scattering and Journals Commissions, the Worldwide Protein Data Bank (wwPDB) Small-Angle Scattering Validation Task Force and additional experts in the field.

A Study of Beryllium-Based Materials and Comparison of Their X-Ray Homogeneities According to Small-Angle Scattering Data

2018 ◽  
Vol 63 (6) ◽  
pp. 874-882 ◽  
Author(s):  
A. A. Semenov ◽  
V. V. Volkov ◽  
A. V. Zabrodin ◽  
V. V. Gorlevskii ◽  
M. S. Sheverdyaev ◽  
...  
Keyword(s):  
Small Angle ◽  
Small Angle Scattering ◽  
Scattering Data ◽  
X Ray ◽  
Angle Scattering

scholarly journals Small-angle scattering data representation in SASCIF and integrative/hybrid methods dictionary

2017 ◽  
Vol 73 (a2) ◽  
pp. C1441-C1441
Author(s):  
Brinda Vallat ◽  
Benjamin Webb ◽  
John Westbrook ◽  
Andrej Sali ◽  
Helen Berman
Keyword(s):  
Small Angle ◽  
Hybrid Methods ◽  
Data Representation ◽  
Small Angle Scattering ◽  
Scattering Data ◽  
Angle Scattering

scholarly journals The canSAS standard for storing reduced one-dimensional small-angle scattering data in XML files

2008 ◽  
Vol 64 (a1) ◽  
pp. C554-C554
Author(s):  
P.R. Jemian ◽  
A.J. Jackson ◽  
S.M. King ◽  
K.C. Littrell ◽  
A.R.J. Nelson ◽  
...  
Keyword(s):  
Small Angle ◽  
Small Angle Scattering ◽  
Scattering Data ◽  
One Dimensional ◽  
Angle Scattering

Small-angle scattering of interacting particles. II. Generalized indirect Fourier transformation under consideration of the effective structure factor for polydisperse systems

1999 ◽  
Vol 32 (2) ◽  
pp. 197-209 ◽  
Author(s):  
B. Weyerich ◽  
J. Brunner-Popela ◽  
O. Glatter
Keyword(s):  
Form Factor ◽  
Small Angle ◽  
Structure Factor ◽  
Fourier Transformation ◽  
Hard Spheres ◽  
Small Angle Scattering ◽  
Scattering Data ◽  
Model Free ◽  
Angle Scattering ◽  
The Gift

The indirect Fourier transformation (IFT) is the method of choice for the model-free evaluation of small-angle scattering data. Unfortunately, this technique is only useful for dilute solutions because, for higher concentrations, particle interactions can no longer be neglected. Thus an advanced technique was developed as a generalized version, the so-called generalized indirect Fourier transformation (GIFT). It is based on the simultaneous determination of the form factor, representing the intraparticle contributions, and the structure factor, describing the interparticle contributions. The former can be determined absolutely free from model assumptions, whereas the latter has to be calculated according to an adequate model. In this paper, various models for the structure factor are compared,e.g.the effective structure factor for polydisperse hard spheres, the averaged structure factor, the local monodisperse approximation and the decoupling approximation. Furthermore, the structure factor for polydisperse rod-like particles is presented. As the model-free evaluation of small-angle scattering data is an essential point of the GIFT technique, the use of a structure factor without any influence of the form amplitude is advisable, at least during the first evaluation procedure. Therefore, a series of simulations are performed to check the possibility of the representation of various structure factors (such as the effective structure factor for hard spheres or the structure factor for rod-like particles) by the less exact but much simpler averaged structure factor. In all the observed cases, it was possible to recover the exact form factor with a free determined parameter set for the structure factor. The resulting parameters of the averaged structure factor have to be understood as apparent model parameters and therefore have only limited physical relevance. Thus the GIFT represents a technique for the model independent evaluation of scattering data with a minimum ofa prioriinformation.

Estimation and fingerprinting of the size distribution of non-interacting spherical particles from small-angle scattering data

2021 ◽  
Vol 54 (5) ◽  
Author(s):  
Debasis Sen ◽  
Ashwani Kumar ◽  
Avik Das ◽  
Jitendra Bahadur
Keyword(s):  
Size Distribution ◽  
Small Angle ◽  
Colloidal Particles ◽  
Nonlinear Least Squares ◽  
Small Angle Scattering ◽  
Spherical Particles ◽  
Scattering Data ◽  
Fitting Procedure ◽  
Angle Scattering ◽  
Log Normal

A new method to estimate the size distribution of non-interacting colloidal particles from small-angle scattering data is presented. The method demonstrates that the distribution can be efficiently retrieved through features of the scattering data when plotted in the Porod representation, thus avoiding the standard fitting procedure of nonlinear least squares. The present approach is elaborated using log-normal and Weibull distributions. The method can differentiate whether the distribution actually follows the functionality of either of these two distributions, unlike the standard fitting procedure which requires a prior assumption of the functionality of the distribution. After validation with various simulated scattering profiles, the formalism is used to estimate the size distribution from experimental small-angle X-ray scattering data from two different dilute dispersions of silica. At present the method is limited to monomodal distributions of dilute spherical particles only.

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