<i>Irena</i>: tool suite for modeling and analysis of small-angle scattering

Ilavský, Ján; Jemian, P.R.

doi:10.1107/s0021889809002222

Cited by 1,415 publications

(1,329 citation statements)

References 62 publications

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“…13 This is done numerically using the so-called TNNLS (Totally Non-Negative Least Squares) method 17 which is one of the optional methods available in the Irena package. 16 It is seen that indeed the distribution is log-normal, dominated by a large peak centred between 300 and 400 Å (30-40 nm) in agreement with the results from the Unified function. For a log-normal distribution particle size distribution, the radius of gyration as determined by the Guinier part of equation (1) which is heavily weighted by the larger particles in the distribution) is in fact equal to the median diameter of the particles in the sample if we consider them to be spherical.…”

Section: Resultssupporting

confidence: 76%

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Small angle x-ray scattering and electron microscopy of nanoparticles formed in an electrical arc

et al. 2013

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Small Angle X-ray Scattering has been used to characterize nanoparticles generated by electrical arcing between metallic (AgSnO2) electrodes. The particles are found to have diameters between 30 and 40 nm and display smooth surfaces suggesting that they are either in liquid form or have solidified from the liquid state. Particles collected around the electrodes were analyzed by Transmission Electron Microscopy and were seen to be much larger than those seen in the SAXS measurement, to be spherical in form and composed of silver metal with irregular tin oxide particles deposited on their surface. Mixed metal nanoparticles can have important practical applications and the use of mixed sintered electrodes may be a direct method for their production

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Section: Resultssupporting

confidence: 76%

“…15 All of the analysis of the scattering data has been performed using the Irena package of Macros developed by Jan Ilavski of the Advanced Photon Source. 16 This allows, for example, the measured data to be fitted to the Unified function and also particle size distributions to be determined.…”

Section: Resultsmentioning

confidence: 99%

Small angle x-ray scattering and electron microscopy of nanoparticles formed in an electrical arc

et al. 2013

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“…For collagen in bovine pericardium, at low strain, the Poisson's ratio appears to have a very high value (15)(16)(17)(18)(19)(20)(21)(22)(23)(24)(25)(26)(27), but for strain above 0.09, the Poisson's ratio is in the range 2.1-2.8. For the total strain (from 0 to 0.25), the change in d-spacing and diameter gives 0 ¼ 2.1 6 0.7 (these values of 0 can be calculated from Fig.…”

Section: Resultsmentioning

confidence: 99%

“…Fibril diameters were calculated from the SAXS data using the Irena software package 24 running within Igor Pro. The data were fitted at the wave vector Q, in the range of 0.01-0.04 Å À1 and at an azimuthal angle which was 90 to the long axis of most of the collagen fibrils.…”

Section: Methodsmentioning

confidence: 99%

Poisson's ratio of collagen fibrils measured by small angle X-ray scattering of strained bovine pericardium

Wells

Sizeland

Kayed

et al. 2015

Journal of Applied Physics

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Type I collagen is the main structural component of skin, tendons, and skin products, such as leather. Understanding the mechanical performance of collagen fibrils is important for understanding the mechanical performance of the tissues that they make up, while the mechanical properties of bulk tissue are well characterized, less is known about the mechanical behavior of individual collagen fibrils. In this study, bovine pericardium is subjected to strain while small angle X-ray scattering (SAXS) patterns are recorded using synchrotron radiation. The change in d-spacing, which is a measure of fibril extension, and the change in fibril diameter are determined from SAXS. The tissue is strained 0.25 (25%) with a corresponding strain in the collagen fibrils of 0.045 observed. The ratio of collagen fibril width contraction to length extension, or the Poisson's ratio, is 2.1 ± 0.7 for a tissue strain from 0 to 0.25. This Poisson's ratio indicates that the volume of individual collagen fibrils decreases with increasing strain, which is quite unlike most engineering materials. This high Poisson's ratio of individual fibrils may contribute to high Poisson's ratio observed for tissues, contributing to some of the remarkable properties of collagen-based materials.

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“…SANS data analysis was carried out using the Irena evaluation routine implemented in commercially available Igor Pro software (Ilavsky and Jemian, 2009). A multilevel unified fit was used to describe the multiple levels of structural organization evident in the scattering data (Beaucage, 1995(Beaucage, , 1996.…”

Section: Sans Measurementsmentioning

confidence: 99%

Gradients in Wall Mechanics and Polysaccharides along Growing Inflorescence Stems

et al. 2017

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At early stages of Arabidopsis (Arabidopsis thaliana) flowering, the inflorescence stem undergoes rapid growth, with elongation occurring predominantly in the apical ;4 cm of the stem. We measured the spatial gradients for elongation rate, osmotic pressure, cell wall thickness, and wall mechanical compliances and coupled these macroscopic measurements with molecular-level characterization of the polysaccharide composition, mobility, hydration, and intermolecular interactions of the inflorescence cell wall using solid-state nuclear magnetic resonance spectroscopy and small-angle neutron scattering. Force-extension curves revealed a gradient, from high to low, in the plastic and elastic compliances of cell walls along the elongation zone, but plots of growth rate versus wall compliances were strikingly nonlinear. Neutron-scattering curves showed only subtle changes in wall structure, including a slight increase in cellulose microfibril alignment along the growing stem. In contrast, solid-state nuclear magnetic resonance spectra showed substantial decreases in pectin amount, esterification, branching, hydration, and mobility in an apical-to-basal pattern, while the cellulose content increased modestly. These results suggest that pectin structural changes are connected with increases in pectin-cellulose interaction and reductions in wall compliances along the apical-to-basal gradient in growth rate. These pectin structural changes may lessen the ability of the cell wall to undergo stress relaxation and irreversible expansion (e.g. induced by expansins), thus contributing to the growth kinematics of the growing stem.

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Irena: tool suite for modeling and analysis of small-angle scattering

Cited by 1,415 publications

References 62 publications

Small angle x-ray scattering and electron microscopy of nanoparticles formed in an electrical arc

Small angle x-ray scattering and electron microscopy of nanoparticles formed in an electrical arc

Poisson's ratio of collagen fibrils measured by small angle X-ray scattering of strained bovine pericardium

Gradients in Wall Mechanics and Polysaccharides along Growing Inflorescence Stems

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