scholarly journals Hierarchical architecture of spider attachment setae reconstructed from scanning nanofocus X-ray diffraction data

2019 ◽  
Vol 16 (150) ◽  
pp. 20180692 ◽  
Author(s):  
Clemens F. Schaber ◽  
Silja Flenner ◽  
Anja Glisovic ◽  
Igor Krasnov ◽  
Martin Rosenthal ◽  
...  
Keyword(s):  
Small Angle ◽  
Adhesive Contact ◽  
Quantitative Information ◽  
Hair Shaft ◽  
Hierarchical Architecture ◽  
X Ray Diffraction ◽  
X Ray ◽  
Dry Adhesion ◽  
Angle Scattering ◽  
Diffraction Patterns

When sitting and walking, the feet of wandering spiders reversibly attach to many surfaces without the use of gluey secretions. Responsible for the spiders' dry adhesion are the hairy attachment pads that are built of specially shaped cuticular hairs (setae) equipped with approximately 1 µm wide and 20 nm thick plate-like contact elements (spatulae) facing the substrate. Using synchrotron-based scanning nanofocus X-ray diffraction methods, combining wide-angle X-ray diffraction/scattering and small-angle X-ray scattering, allowed substantial quantitative information to be gained about the structure and materials of these fibrous adhesive structures with 200 nm resolution. The fibre diffraction patterns showed the crystalline chitin chains oriented along the long axis of the attachment setae and increased intensity of the chitin signal dorsally within the seta shaft. The small-angle scattering signals clearly indicated an angular shift by approximately 80° of the microtrich structures that branch off the bulk hair shaft and end as the adhesive contact elements in the tip region of the seta. The results reveal the specific structural arrangement and distribution of the chitin fibres within the attachment hair's cuticle preventing material failure by tensile reinforcement and proper distribution of stresses that arise upon attachment and detachment.

An X-Ray Small-Angle Scattering Instrument

1967 ◽  
Vol 11 ◽  
pp. 332-338 ◽  
Author(s):  
Donald M. Koffman
Keyword(s):  
Small Angle ◽  
Scintillation Counter ◽  
Small Angle Scattering ◽  
High Angular Resolution ◽  
X Ray Diffraction ◽  
Multiple Diffraction ◽  
Double Crystal ◽  
X Ray ◽  
Angle Scattering ◽  
Diffraction Patterns

AbstractAn X-ray small-angle scattering instrument is described which is used for recording X-ray diffraction patterns or small-angle X-ray scattering curves in an angular region very close to the direct beam. The measurement of X-ray intensity is accomplished with standard geiger or scintillation counter techniques. The instrument is designed for use with a spot-focus or vertical-line X-ray source, In essence, it is a multiple-reflection double-crystal diffractometer, based on a concept developed by Bonse and Hart, employing two grooved perfect germanium crystals arranged in the parallel position. Multiple diffraction from these crystals produces a monochromated X-ray beam which can be several millimeters wide while still exhibiting extremely high angular resolution. As a result, effective sample volumes can be employed with maximum volume-to-thickness ratios. The principal features of the instrument are discussed with emphasis on the advantages of this device over those employing complex slit systems and film-re cording techniques, Data are presented to illustrate the operation, intensity, and resolution of the unit.

SLADS: a parallel code for direct simulations of scattering of large anisotropic dense nanoparticle systems

2017 ◽  
Vol 50 (3) ◽  
pp. 951-958 ◽  
Author(s):  
Sen Chen ◽  
Juncheng E ◽  
Sheng-Nian Luo
Keyword(s):  
Analytical Solutions ◽  
Small Angle ◽  
Real Space ◽  
Small Angle Scattering ◽  
Two Dimensional ◽  
X Ray ◽  
X Ray Scattering ◽  
Angle Scattering ◽  
Parallel Code ◽  
Diffraction Patterns

SLADS(http://www.pims.ac.cn/Resources.html), a parallel code for direct simulations of X-ray scattering of large anisotropic dense nanoparticle systems of arbitrary species and atomic configurations, is presented. Particles can be of arbitrary shapes and dispersities, and interactions between particles are considered. Parallelization is achieved in real space for the sake of memory limitation. The system sizes attempted are up to one billion atoms, and particle concentrations in dense systems up to 0.36. Anisotropy is explored in terms of superlattices. One- and two-dimensional small-angle scattering or diffraction patterns are obtained.SLADSis validated self-consistently or against cases with analytical solutions.

Bioinspired synthesis of self-assembled calcium phosphate nanocomposites using block copolymer-peptide conjugates

2008 ◽  
Vol 23 (12) ◽  
pp. 3196-3212 ◽  
Author(s):  
Yusuf Yusufoglu ◽  
Yanyan Hu ◽  
Mathumai Kanapathipillai ◽  
Matthew Kramer ◽  
Yunus E. Kalay ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Calcium Phosphate ◽  
Small Angle ◽  
Polymer Chains ◽  
X Ray Diffraction ◽  
X Ray ◽  
Self Assembling ◽  
Transmission Electron ◽  
Angle Scattering ◽  
Inorganic Content

Thermoreversibly gelling block copolymers conjugated to hydroxyapatite-nucleating peptides were used to template the growth of inorganic calcium phosphate in aqueous solutions. Nuclear magnetic resonance (NMR), Fourier transform infrared (FTIR), transmission electron microscopy, x-ray diffraction, and small-angle scattering were used to characterize these samples and confirm that the peptides promoted the growth of hydroxyapatite as the inorganic phase. Three different polymer templates were used with varying charges on the polymer chains (nonionic, anionic, and zwitterionic), to investigate the role of charge on mineralization. All of the polymer-inorganic solutions exhibited thermoreversible gelation above room temperature. Nanocomposite formation was confirmed by solid-state NMR, and several methods identified the inorganic component as hydroxyapatite. Small angle x-ray scattering and electron microscopy showed thin, elongated crystallites. Thermogravimetric analysis showed an inorganic content of 30–45 wt% (based on the mass of the dried gel at ∼200 °C) in the various samples. Our work offers routes for bioinspired bottom-up approaches for the development of novel, self-assembling, injectable nanocomposite biomaterials for potential orthopedic applications.

A model-independent maximum-entropy method for the inversion of small-angle X-ray diffraction patterns

1999 ◽  
Vol 32 (6) ◽  
pp. 1069-1083 ◽  
Author(s):  
J. A. Elliott ◽  
S. Hanna
Keyword(s):  
Maximum Entropy ◽  
Small Angle ◽  
Disordered Systems ◽  
Maximum Entropy Method ◽  
Structural Model ◽  
Entropy Method ◽  
X Ray Diffraction ◽  
X Ray ◽  
Model Independent ◽  
Diffraction Patterns

A model-independent maximum-entropy method is presented which will produce a structural model from small-angle X-ray diffraction data of disordered systems using no other prior information. In this respect, it differs from conventional maximum-entropy methods which assume the form of scattering entitiesa priori. The method is demonstrated using a number of different simulated diffraction patterns, and applied to real data obtained from perfluorinated ionomer membranes, in particular Nafion™, and a liquid crystalline copolymer of 1,4-oxybenzoate and 2,6-oxynaphthoate (B–N).

Characterization of Polyquinoline Blends Using Small Angle Scattering

1989 ◽  
Vol 171 ◽  
Author(s):  
Wen-Li Wu ◽  
John K. Stille ◽  
Joseph W. Tsang ◽  
Alex J. Parker
Keyword(s):  
Small Angle ◽  
Quantitative Information ◽  
Flexible Chain ◽  
X Ray ◽  
Molecular Dispersion ◽  
Angle Scattering ◽  
Scattering Measurements ◽  
Rigid Rod ◽  
Scattering Contribution

ABSTRACTTo determine the compatibility between the rigid rod and the flexible chain polyquinolines, both small angle x-ray and neutron scattering measurements were conducted on blends containing deuterated flexible chains. The scattering intensities from both x-ray and neutron were reduced to their absolute scales in order to remove the scattering contribution from microvoids which tended to overshadow the signal of molecular origin. Quantitative information regarding the molecular dispersion in a 50/50 rigid rod and flexible chain blend was obtained. The result indicated that this material was partially segregated but not to the point of single component phases.

A Comparison of Small Angle Neutron Scattering and X-Ray Diffraction Studies of Cobalt Precipitates in A Cu-0.95 at. % Co Alloy

1986 ◽  
Vol 82 ◽  
Author(s):  
S. Spooner ◽  
S. Iida ◽  
B. C. Larson
Keyword(s):  
Small Angle ◽  
Large Angle ◽  
Detailed Comparison ◽  
Scattering Data ◽  
Single Crystal Sample ◽  
X Ray Diffraction ◽  
Data Set ◽  
Crystal Sample ◽  
X Ray ◽  
Angle Scattering

ABSTRACTA detailed comparison of small-angle scattering (SANS) and large angle x-ray diffraction methods of characterization of precipitates was undertaken. Cobalt-rich precipitates on the order of 50 Å developed after a 17 hour anneal at 570°C were studied in a single crystal sample with SANS and with diffuse x-ray scattering near the (400)Bragg peak. Each scattering data set was analyzed independently in terms of a distribution of precipitate sizes; a detailed comparison is made of the size distribution obtained. A small interparticle interference effect is seen.

Small-angle scattering of X-rays in a conventional Bragg–Brentano diffractometer for quantitative analysis

1995 ◽  
Vol 10 (3) ◽  
pp. 170-172
Author(s):  
Stefano Battaglia
Keyword(s):  
Quantitative Analysis ◽  
Diffraction Analysis ◽  
Small Angle ◽  
Carbonate Rocks ◽  
International Standards ◽  
X Rays ◽  
X Ray Diffraction ◽  
X Ray ◽  
Orientation Effects ◽  
Angle Scattering

A technique is presented utilizing an unmodified commercial X-ray diffractometer, equipped with a Bragg–Brentano geometry, for reducing preferred orientation effects in measured intensities during quantitative diffraction analysis. The diffractometer setup examined makes possible data acquisition with Θ fixed at 1° and 2Θ scanning the Bragg line. The results obtained with this technique are shown in the quantitative X-ray diffraction analysis of three international standards of carbonate rocks (401,402,403).

Effect of finite spatial coherence length on small-angle scattering

2015 ◽  
Vol 48 (6) ◽  
pp. 1660-1664 ◽  
Author(s):  
Yuya Shinohara ◽  
Yoshiyuki Amemiya
Keyword(s):  
Small Angle ◽  
Coherence Length ◽  
Spatial Coherence ◽  
Small Angle Scattering ◽  
Forward Scattering ◽  
X Ray Diffraction ◽  
X Ray ◽  
X Ray Imaging ◽  
Angle Scattering ◽  
Diffraction Imaging

This study shows that forward scattering at the origin of reciprocal space contributes to the scattering intensity profiles of ultra-small-angle scattering. The forward scattering corresponds to a Fourier transform of the X-ray coherent volume on a sample. This contribution is usually ignored in the study of small-angle scattering, while it is fully considered in the fields of X-ray imaging, such as coherent X-ray diffraction imaging and X-ray ptychography. This effect is explicitly illustrated in the context of small-angle scattering, and the effect of a finite spatial coherence length on small-angle scattering is discussed.

scholarly journals A simple model for dynamic small-angle X-ray diffraction in colloidal crystals

2007 ◽  
Vol 40 (1) ◽  
pp. 144-150 ◽  
Author(s):  
Alex G. F. de Beer ◽  
Andrei V. Petukhov
Keyword(s):  
Simple Model ◽  
Small Angle ◽  
Colloidal Crystals ◽  
X Ray Diffraction ◽  
X Ray ◽  
Diffraction Patterns

A simple model is presented that allows calculation of the small-angle X-ray diffraction patterns of perfect colloidal crystals. The model is based on the Wentzel–Kramers–Brillouin approximation and permits a straightforward evaluation of multibeam interactions. Results are illustrated by several examples.

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