ISPyB for BioSAXS, the gateway to user autonomy in solution scattering experiments

Energy Technology Data Exchange (ETDEWEB)

De Maria Antolinos, Alejandro; Pernot, Petra; Brennich, Martha E.; Kieffer, Jérôme [European Synchrotron Radiation Facility, 71 avenue des Martyrs, CS 40220, 38042 Grenoble (France); Bowler, Matthew W. [European Molecular Biology Laboratory, Grenoble Outstation, 71 avenue des Martyrs, CS 90181, 38042 Grenoble (France); Université Grenoble Alpes–EMBL–CNRS, 71 avenue des Martyrs, CS 90181, 38042 Grenoble (France); Delageniere, Solange; Ohlsson, Staffan; Malbet Monaco, Stephanie [European Synchrotron Radiation Facility, 71 avenue des Martyrs, CS 40220, 38042 Grenoble (France); Ashton, Alun [DLS, Diamond House, Harwell Science and Innovation Campus, Fermi Avenue, Didcot OX11 0QX (United Kingdom); Franke, Daniel; Svergun, Dmitri [European Molecular Biology Laboratory, Hamburg Outstation, c/o DESY, Building 25A, Notkestrasse 85, 22603 Hamburg (Germany); McSweeney, Sean; Gordon, Elspeth [European Synchrotron Radiation Facility, 71 avenue des Martyrs, CS 40220, 38042 Grenoble (France); Round, Adam, E-mail: around@embl.fr [European Molecular Biology Laboratory, Grenoble Outstation, 71 avenue des Martyrs, CS 90181, 38042 Grenoble (France); Université Grenoble Alpes–EMBL–CNRS, 71 avenue des Martyrs, CS 90181, 38042 Grenoble (France); European Synchrotron Radiation Facility, 71 avenue des Martyrs, CS 40220, 38042 Grenoble (France)

2015-01-01

The ISPyB information-management system for crystallography has been adapted to include data from small-angle X-ray scattering of macromolecules in solution experiments. Logging experiments with the laboratory-information management system ISPyB (Information System for Protein crystallography Beamlines) enhances the automation of small-angle X-ray scattering of biological macromolecules in solution (BioSAXS) experiments. The ISPyB interface provides immediate user-oriented online feedback and enables data cross-checking and downstream analysis. To optimize data quality and completeness, ISPyBB (ISPyB for BioSAXS) makes it simple for users to compare the results from new measurements with previous acquisitions from the same day or earlier experiments in order to maximize the ability to collect all data required in a single synchrotron visit. The graphical user interface (GUI) of ISPyBB has been designed to guide users in the preparation of an experiment. The input of sample information and the ability to outline the experimental aims in advance provides feedback on the number of measurements required, calculation of expected sample volumes and time needed to collect the data: all of this information aids the users to better prepare for their trip to the synchrotron. A prototype version of the ISPyBB database is now available at the European Synchrotron Radiation Facility (ESRF) beamline BM29 and is already greatly appreciated by academic users and industrial clients. It will soon be available at the PETRA III beamline P12 and the Diamond Light Source beamlines I22 and B21.

Conformational Flexibility of Proteins Involved in Ribosome Biogenesis: Investigations via Small Angle X-ray Scattering (SAXS

Directory of Open Access Journals (Sweden)

Dritan Siliqi

2018-02-01

Full Text Available The dynamism of proteins is central to their function, and several proteins have been described as flexible, as consisting of multiple domains joined by flexible linkers, and even as intrinsically disordered. Several techniques exist to study protein structures, but small angle X-ray scattering (SAXS has proven to be particularly powerful for the quantitative analysis of such flexible systems. In the present report, we have used SAXS in combination with X-ray crystallography to highlight their usefulness at characterizing flexible proteins, using as examples two proteins involved in different steps of ribosome biogenesis. The yeast BRCA2 and CDKN1A-interactig protein, Bcp1, is a chaperone for Rpl23 of unknown structure. We showed that it consists of a rigid, slightly elongated protein, with a secondary structure comprising a mixture of alpha helices and beta sheets. As an example of a flexible molecule, we studied the SBDS (Shwachman-Bodian-Diamond Syndrome protein that is involved in the cytoplasmic maturation of the 60S subunit and constitutes the mutated target in the Shwachman-Diamond Syndrome. In solution, this protein coexists in an ensemble of three main conformations, with the N- and C-terminal ends adopting different orientations with respect to the central domain. The structure observed in the protein crystal corresponds to an average of those predicted by the SAXS flexibility analysis.

Complex fluids under microflow probed by SAXS: rapid microfabrication and analysis

International Nuclear Information System (INIS)

Martin, Hazel P; Luckham, Paul F; Cabral, Joao T; Brooks, Nicholas J; Seddon, John M; Terrill, Nick J; Kowalski, Adam J

2010-01-01

We report a combined microfluidic and online synchrotron small-angle X-ray scattering (SAXS) study of complex surfactant mixtures under flow. We investigate the influence of a series of flow constrictions, generating well-defined, periodic extensional flow fields, on the microstructure of two model surfactant mixtures containing SDS and CTAC. Specifically, the lamella spacing, orientation and structural order are reported and correlated with the imposed flow field: geometry, flow velocity and residence time. The design, fabrication and operation of a microfluidic system using rapid prototyping is described in detail. We show that polydimethyl siloxane (PDMS), ubiquitous in microfabrication, provides a suitable matrix for SAXS microdevices provided that: (i) PDMS thickness are kept to a minimum while retaining structural integrity (∼1000μm) and (ii) scattering from the structure of interest is sufficiently decoupled from the amorphous background scattering. The combination SAXS-microfluidics provides unprecedented opportunities to elucidate the non-equilibrium structure formation and relaxation of complex fluids, demonstrated here for concentrated surfactant mixtures.

Complex fluids under microflow probed by SAXS: rapid microfabrication and analysis

Energy Technology Data Exchange (ETDEWEB)

Martin, Hazel P; Luckham, Paul F; Cabral, Joao T [Department of Chemical Engineering, Imperial College London, Exhibition Road, London SW7 2AZ (United Kingdom); Brooks, Nicholas J; Seddon, John M [Department of Chemistry, Imperial College London, Exhibition Road, London SW7 2AZ (United Kingdom); Terrill, Nick J [Diamond Light Source Ltd., Diamond House, Harwell Science and Innovation Campus, Chilton, Didcot, Oxfordshire, OX11 0DE (United Kingdom); Kowalski, Adam J, E-mail: j.cabral@imperial.ac.u [Unilever Research and Development, Port Sunlight Laboratory, Bebington, Wirral, CH63 3JW (United Kingdom)

2010-10-01

We report a combined microfluidic and online synchrotron small-angle X-ray scattering (SAXS) study of complex surfactant mixtures under flow. We investigate the influence of a series of flow constrictions, generating well-defined, periodic extensional flow fields, on the microstructure of two model surfactant mixtures containing SDS and CTAC. Specifically, the lamella spacing, orientation and structural order are reported and correlated with the imposed flow field: geometry, flow velocity and residence time. The design, fabrication and operation of a microfluidic system using rapid prototyping is described in detail. We show that polydimethyl siloxane (PDMS), ubiquitous in microfabrication, provides a suitable matrix for SAXS microdevices provided that: (i) PDMS thickness are kept to a minimum while retaining structural integrity ({approx}1000{mu}m) and (ii) scattering from the structure of interest is sufficiently decoupled from the amorphous background scattering. The combination SAXS-microfluidics provides unprecedented opportunities to elucidate the non-equilibrium structure formation and relaxation of complex fluids, demonstrated here for concentrated surfactant mixtures.

Pepsi-SAXS : an adaptive method for rapid and accurate computation of small-angle X-ray scattering profiles

OpenAIRE

Grudinin , Sergei; Garkavenko , Maria; Kazennov , Andrei

2017-01-01

International audience; A new method called Pepsi-SAXS is presented that calculates small-angle X-ray scattering profiles from atomistic models. The method is based on the multipole expansion scheme and is significantly faster compared with other tested methods. In particular, using the Nyquist–Shannon–Kotelnikov sampling theorem, the multipole expansion order is adapted to the size of the model and the resolution of the experimental data. It is argued that by using the adaptive expansion ord...

ISPyB for BioSAXS, the gateway to user autonomy in solution scattering experiments.

Science.gov (United States)

De Maria Antolinos, Alejandro; Pernot, Petra; Brennich, Martha E; Kieffer, Jérôme; Bowler, Matthew W; Delageniere, Solange; Ohlsson, Staffan; Malbet Monaco, Stephanie; Ashton, Alun; Franke, Daniel; Svergun, Dmitri; McSweeney, Sean; Gordon, Elspeth; Round, Adam

2015-01-01

Logging experiments with the laboratory-information management system ISPyB (Information System for Protein crystallography Beamlines) enhances the automation of small-angle X-ray scattering of biological macromolecules in solution (BioSAXS) experiments. The ISPyB interface provides immediate user-oriented online feedback and enables data cross-checking and downstream analysis. To optimize data quality and completeness, ISPyBB (ISPyB for BioSAXS) makes it simple for users to compare the results from new measurements with previous acquisitions from the same day or earlier experiments in order to maximize the ability to collect all data required in a single synchrotron visit. The graphical user interface (GUI) of ISPyBB has been designed to guide users in the preparation of an experiment. The input of sample information and the ability to outline the experimental aims in advance provides feedback on the number of measurements required, calculation of expected sample volumes and time needed to collect the data: all of this information aids the users to better prepare for their trip to the synchrotron. A prototype version of the ISPyBB database is now available at the European Synchrotron Radiation Facility (ESRF) beamline BM29 and is already greatly appreciated by academic users and industrial clients. It will soon be available at the PETRA III beamline P12 and the Diamond Light Source beamlines I22 and B21.

SAXS Combined with UV-vis Spectroscopy and QELS: Accurate Characterization of Silver Sols Synthesized in Polymer Matrices.

Science.gov (United States)

Bulavin, Leonid; Kutsevol, Nataliya; Chumachenko, Vasyl; Soloviov, Dmytro; Kuklin, Alexander; Marynin, Andrii

2016-12-01

The present work demonstrates a validation of small-angle X-ray scattering (SAXS) combining with ultra violet and visible (UV-vis) spectroscopy and quasi-elastic light scattering (QELS) analysis for characterization of silver sols synthesized in polymer matrices. Polymer matrix internal structure and polymer chemical nature actually controlled the sol size characteristics. It was shown that for precise analysis of nanoparticle size distribution these techniques should be used simultaneously. All applied methods were in good agreement for the characterization of size distribution of small particles (less than 60 nm) in the sols. Some deviations of the theoretical curves from the experimental ones were observed. The most probable cause is that nanoparticles were not entirely spherical in form.

Morphology of blends of linear and long-chain-branched polyethylenes in the solid state: A study by SANS, SAXS, and DSC

International Nuclear Information System (INIS)

Wignall, G.D.; Londono, J.D.; Lin, J.S.; Alamo, R.G.; Galante, M.J.; Mandelkern, L.

1995-01-01

Differential scanning calorimetry (DSC), small-angle neutron scattering (SANS), and X-ray scattering (SAXS) have been used to investigate the solid-state morphology of blends of linear (high density) and long-chain-branched (low-density) polyethylenes (HDPE/LDPE). The blends are homogeneous in the melt, as previously demonstrated by SANS using the contrast obtained by deuterating the linear polymer. However, due to the structural and melting point differences (∼ 20 C) between HDPE and LDPE, the components may phase segregate on slow cooling (0.75 C/min). For high concentrations (φ ≥ 0.5) of HDPE, relatively high rates of crystallization of the linear component lead to the formation of separate stacks of HDPE and LDPE lamellae, as indicated by two-peak SAXS curves. For predominantly branched blends, the difference in crystallization rate of the components becomes smaller and only one SAXS peak is observed, indicating that the two species are in the same lamellar stack. Moreover, the phases no longer consist of the pure component and the HDPE lamellae contain up to 15--20% LDPE (and vice versa). Rapid quenching into dry ice/2-propanol (-78 C) produces only one SAXS peak (and hence one lamellar stack) over the whole concentration range. The blends show extensive cocrystallization, along with a tendency for the branched material to be preferentially located in the amorphous interlamellar regions. For high concentrations (φ > 0.5) of HDPE-D, the overall scattering length density (SLD) is high and the excess concentration of LDPE between the lamellae enhances the SLD contrast between the crystalline and amorphous phases. Thus, the interlamellar spacing (long period) is clearly visible in the SANS pattern. The blend morphology is a strong function of the quenching rate, and samples quenched less rapidly (e.g., into water at 23 C) are similar to slowly cooled blends

Characterization of bentonite pore structure by combining chloride porosity and SAXS measurements

International Nuclear Information System (INIS)

Muurinen, A.

2010-01-01

Document available in extended abstract form only. The total water porosity, chloride porosity and the microstructure were studied in compacted samples prepared from MX-80 and Deponit bentonites equilibrated through filter plates with 0.1 M NaCl solution for 12.5 months. The dry densities of the samples varied approximately from 0.7 to 1.55 g/cm 3 . XRD and SAXS (Small Angle X-ray Scattering) were used to study the microstructure of the bentonites. It was obvious that the chloride porosity was lower than the water porosity in both clays, which indicates the exclusion caused by the negatively charged montmorillonite surfaces. In the XRD and SAXS measurements the measured basal spaces represented by the diffraction peaks were smaller than the theoretical ones assuming a homogenous microstructure. This indicates that there was a substantial amount of water also in the pores, which were not represented by the peaks. This could explain the difference between the measured chloride porosity and the modelling curve obtained with the Donnan model. By combining the information from the SAXS measurements and the chloride exclusion measurements, it was possible to evaluate the volumes of the soft and dense fractions and the pore sizes in each fraction for MX-80. The chloride porosity was mostly caused by the pores in the soft clay where the pore size is larger. The volume of the soft fraction decreased and its density increased with increasing density of the sample. (authors)

A saxs study of silica aerogels

International Nuclear Information System (INIS)

Craievich, A.F.

1986-01-01

Aerogels produced by hypercritical drying of gels from hydrolysis of TMOS (Tetramethoxysilane) in various pH conditions and subjected to a densification process were studied by SAXS using LURE synchrotron facility. The evaluation of scattering data combined with BET measurements leads to a model of aerogels consisting of a light density matrix in which meso-and macro-pores are embedded. (Author) [pt

GISAXS and SAXS studies on the spatial structures of Co nanowire arrays

International Nuclear Information System (INIS)

Cheng Weidong; Xing Xueqing; Wang Dehong; Gong Yu; Mo Guang; Cai Quan; Chen Zhongjun; Wu Zhonghua

2011-01-01

The spatial structures of magnetic Co nanowire array embedded in anodic aluminium membranes were investigated by grazing incidence small angle X-ray scattering (GISAXS) and conventional small angle X-ray scattering (SAXS) techniques. Compared with SEM observation, the GISAXS and SAXS measurements can get more overall structural information in a large-area scale. In this study, the two-dimensional GISAXS pattern was well reconstructed by using the IsGISAXS program. The results demonstrate that the hexagonal lattice formed by the Co nanowires is distorted (a≈105 nm, b≈95 nm). These Co nanowires are isolated into many structure domains with different orientations with a size of about 2 μm. The SAXS results have also confirmed that the nanopore structures in the AAM can be retained after depositing Co nanowires although the Co nanowires can not completely but only just fill up the nanopores. These results are helpful for understanding the global structure of the Co nanowire array. (authors)

In situ SAXS experiment during DNA and liposome complexation

Energy Technology Data Exchange (ETDEWEB)

Gasperini, A.A.; Cavalcanti, L.P. [Laboratorio Nacional de Luz Sincrotron (LNLS), Campinas, SP (Brazil); Balbino, T.A.; Torre, L.G. de la [Universidade Estadual de Campinas (UNICAMP), SP (Brazil); Oliveira, C.L.P. [Universidade de Sao Paulo (USP), Sao Paulo, SP (Brazil)

2012-07-01

Full text: Gene therapy is an exciting research area that allows the treatment of different diseases. Basically, an engineered DNA that codes a protein is the therapeutic drug that has to be delivered to the cell nucleus. After that, the DNA transfection process allows the protein production using the cell machinery. However, the efficient delivery needs DNA protection against nucleases and interstitial fluids. In this context, the use of cationic liposome/DNA complexes is a promising strategy for non-viral gene therapy. Liposomes are lipid systems that self-aggregate in bilayers and the use of cationic lipids allows the electrostatic complexation with DNA. In this work, we used SAXS technique to study the complexation kinetics between cationic liposomes and plasmid DNA and evaluate the liposome structural modifications in the presence of DNA. Liposomes were prepared according to [1] using as plasmid DNA vector model a modified version of pVAX1-GFP with luciferase as reporter gene [2]. The complexation was promoted in a SAXS sample holder containing a microchannel to get access to the compartment between two mica windows where the X-ray beam could cross through [3]. We obtained in situ complexation using such sample holder coupled to a fed-batch reactor through a peristaltic pump. The scattering curves were recorded each 30 seconds during the cycles. The DNA was added until a certain final ratio between surface charges previously determined. We studied the form and structure factor model for the liposome bilayer to fit the scattering curves [4]. Structural information such as the bilayer electronic density profiles, number of bilayers and fluidity were determined as a function of the complexation with DNA. These differences can reflect in singular in vitro and in vivo effects. [1] L. G. de la Torre et al. Colloids and Surfaces B: Biointerfaces, 73, 175 (2009) [2] A. R. Azzoni et al. The Journal of Gene Medicine, 9, 392 (2007) [3] L. P. Cavalcanti et al. Review of

Computational Analysis of SAXS Data Acquisition.

Science.gov (United States)

Dong, Hui; Kim, Jin Seob; Chirikjian, Gregory S

2015-09-01

Small-angle x-ray scattering (SAXS) is an experimental biophysical method used for gaining insight into the structure of large biomolecular complexes. Under appropriate chemical conditions, the information obtained from a SAXS experiment can be equated to the pair distribution function, which is the distribution of distances between every pair of points in the complex. Here we develop a mathematical model to calculate the pair distribution function for a structure of known density, and analyze the computational complexity of these calculations. Efficient recursive computation of this forward model is an important step in solving the inverse problem of recovering the three-dimensional density of biomolecular structures from their pair distribution functions. In particular, we show that integrals of products of three spherical-Bessel functions arise naturally in this context. We then develop an algorithm for the efficient recursive computation of these integrals.

Bentonite pore structure based on SAXS, chloride exclusion and NMR studies

International Nuclear Information System (INIS)

Muurinen, A.; Carlsson, T.

2013-11-01

Water-saturated bentonite is planned to be used in many countries as an important barrier component in high-level nuclear waste (HLW) repositories. Knowledge about the microstructure of the bentonite and the distribution of water between interlayer and non-interlayer pores is important for modelling of long-term processes. In this work the microstructure of water-saturated samples prepared from Na montmorillonite, Ca-montmorillonite, sodium bentonite MX-80 and calcium bentonite Deponit CaN were studied with nuclear magnetic resonance (NMR) and small-angle xray scattering spectroscopy (SAXS). The sample dry densities ranged between 0.3 and 1.6 g/cm 3 . The NMR technique was used to get information about the volumes of different water types in the bentonite samples. The results were obtained using 1H NMR spin-lattice T 1ρ relaxation time measurements using the short inter-pulse method. The interpretation of the NMR results was made by fitting distributions of exponentials to observed decay curves. The SAXS measurements were used to get information about the size distribution of the interlayer distance of montmorillonite. The chloride porosity measurements and Donnan exclusion calculations were used together with the SAXS results for evaluation of the bentonite microstructure. The NMR studies and SAXS studies coupled with Cl porosity measurements provided very similar pictures of how the porewater is divided in interlayer and non-interlayer water in MX-80 bentonite. In the case where MX-80 of a dry density 1.6 g/cm 3 was equilibrated with 0.1 M NaCl solution, the results indicated an interlayer porosity of 30 % and non-interlayer porosity of 12 %. The interlayer space mainly contained two water layers but also spaces with more water layers were present. The average size of the non-interlayer pores was evaluated to be 120 - 150 A. From the montmorillonite surface area 98 % was interlayer and 2 % non-interlayer. Evaluation of the interlayer and non

Characterization of structure and coagulation behaviour of refractory organic substances (ROS) using small-angle neutron scattering (SANS), small-angle x-ray scattering (SAXS) and x-ray microscopy; Charakterisierung von Struktur und Koagulationsverhalten von Refraktaeren Organischen Saeuren (ROS) mit Hilfe von Neutronenkleinwinkelstreuung (SANS), Roentgenkleinwinkelstreuung (SAXS) und Roentgenmikroskopie

Energy Technology Data Exchange (ETDEWEB)

Pranzas, P.K. [GKSS-Forschungszentrum Geesthacht GmbH (Germany). Inst. fuer Werkstofforschung

1999-07-01

In this work structure, coagulation and complexation behaviour of aquatic refractory organic substances (ROS) (humic and fulvic acids) were characterized. For this purpose a structural analytical system with the methods small-angle neutron scattering (SANS), small-angle x-ray scattering (SAXS) and X-ray microscopy with synchrotron radiation was developed and established. Size distributions of ROS of different origin were calculated from the scattering curves. Spherical ROS units were obtained, which coagulated by forming chainlike structures or disordered ROS agglomerates at higher concentrations. Additionally the average molecular weights of several ROS were calculated. Studies of the coagulation behaviour of ROS towards copper ions resulted in larger ROS-agglomerates besides the spherical ROS units. A linear relation between the addition of Cu{sup 2+} and the formation of the ROS-Cu{sup 2+}-agglomerates was found. With X-ray microscopy an extensive ROS-Cu{sup 2}-network structure could be registrated. For mercury and cadmium ions such coagulation interactions were not found. Investigations with X-ray microscopy of the coagulation behaviour of ROS towards the cationic surfactant DTB resulted in micel-like structures of equal size, which were spread throughout the solution. With increasing concentrations of DTB larger agglomerates up to network structures were obtained. (orig.) [German] In dieser Arbeit wurden Struktur, Koagulations- und Komplexierungsverhalten von aquatischen refraktaeren organischen Saeuren (ROS) (Humin- und Fulvinsaeuren) charakterisiert. Zu diesem Zweck wurde ein strukturanalytisches Gesamtsystem mit den Methoden Neutronenkleinwinkelstreuung (SANS), Roentgenkleinwinkelstreuung (SAXS) und Roentgenmikroskopie mit Synchrotronstrahlung entwickelt und etabliert. Fuer ROS unterschiedlicher Herkunft in Loesung wurden Groessenverteilungen aus den Streukurven berechnet. Es wurden kugelfoermige ROS-Einheiten gefunden, die bei hoeheren ROS

Complementary SAXS and SANS for structural characteristics of a polyurethethane elastomer of low hard-segment content

International Nuclear Information System (INIS)

Sun, Y.-S.; Jeng, U-S.; Huang, Y.-S.; Liang, K.S.; Lin, T.-L.; Tsao, C.-S.

2006-01-01

A polyurethane (PU) elastomer film based on segmented poly(tetramethylene oxide) (PTMO) has been studied using wide-angle X-ray scattering (WAXS), and small-angle X-ray and neutron scattering (SAXS and SANS). The broad WAXS peaks measured for the PU elastomer reveal a low crystallinity of the soft segments PTMO and no crystalline domains for the hard segments, methylene bis(4-isocynatobenzene) (MDI), at 20 deg. C. Whereas small-angle scattering indicates the existence of hard-segment-rich aggregates. Using the contrast variation provided by the SANS and SAXS, we have extracted detailed structural information of the aggregates, including the shape, size, and the aggregation numbers

Sub-millisecond time-resolved SAXS using a continuous-flow mixer and X-ray microbeam.

Science.gov (United States)

Graceffa, Rita; Nobrega, R Paul; Barrea, Raul A; Kathuria, Sagar V; Chakravarthy, Srinivas; Bilsel, Osman; Irving, Thomas C

2013-11-01

Small-angle X-ray scattering (SAXS) is a well established technique to probe the nanoscale structure and interactions in soft matter. It allows one to study the structure of native particles in near physiological environments and to analyze structural changes in response to variations in external conditions. The combination of microfluidics and SAXS provides a powerful tool to investigate dynamic processes on a molecular level with sub-millisecond time resolution. Reaction kinetics in the sub-millisecond time range has been achieved using continuous-flow mixers manufactured using micromachining techniques. The time resolution of these devices has previously been limited, in part, by the X-ray beam sizes delivered by typical SAXS beamlines. These limitations can be overcome using optics to focus X-rays to the micrometer size range providing that beam divergence and photon flux suitable for performing SAXS experiments can be maintained. Such micro-SAXS in combination with microfluidic devices would be an attractive probe for time-resolved studies. Here, the development of a high-duty-cycle scanning microsecond-time-resolution SAXS capability, built around the Kirkpatrick-Baez mirror-based microbeam system at the Biophysics Collaborative Access Team (BioCAT) beamline 18ID at the Advanced Photon Source, Argonne National Laboratory, is reported. A detailed description of the microbeam small-angle-scattering instrument, the turbulent flow mixer, as well as the data acquisition and control and analysis software is provided. Results are presented where this apparatus was used to study the folding of cytochrome c. Future prospects for this technique are discussed.

Effect of iron oxide loading on magnetoferritin structure in solution as revealed by SAXS and SANS.

Science.gov (United States)

Melníková, L; Petrenko, V I; Avdeev, M V; Garamus, V M; Almásy, L; Ivankov, O I; Bulavin, L A; Mitróová, Z; Kopčanský, P

2014-11-01

Synthetic biological macromolecule of magnetoferritin containing an iron oxide core inside a protein shell (apoferritin) is prepared with different content of iron. Its structure in aqueous solution is analysed by small-angle synchrotron X-ray (SAXS) and neutron (SANS) scattering. The loading factor (LF) defined as the average number of iron atoms per protein is varied up to LF=800. With an increase of the LF, the scattering curves exhibit a relative increase in the total scattered intensity, a partial smearing and a shift of the match point in the SANS contrast variation data. The analysis shows an increase in the polydispersity of the proteins and a corresponding effective increase in the relative content of magnetic material against the protein moiety of the shell with the LF growth. At LFs above ∼150, the apoferritin shell undergoes structural changes, which is strongly indicative of the fact that the shell stability is affected by iron oxide presence. Copyright © 2014 Elsevier B.V. All rights reserved.

Sub-millisecond time-resolved SAXS using a continuous-flow mixer and X-ray microbeam

International Nuclear Information System (INIS)

Graceffa, Rita; Nobrega, R. Paul; Barrea, Raul A.; Kathuria, Sagar V.; Chakravarthy, Srinivas; Bilsel, Osman; Irving, Thomas C.

2013-01-01

The development of a high-duty-cycle microsecond time-resolution SAXS capability at the Biophysics Collaborative Access Team beamline (BioCAT) 18ID at the Advanced Photon Source, Argonne National Laboratory, USA, is reported. Small-angle X-ray scattering (SAXS) is a well established technique to probe the nanoscale structure and interactions in soft matter. It allows one to study the structure of native particles in near physiological environments and to analyze structural changes in response to variations in external conditions. The combination of microfluidics and SAXS provides a powerful tool to investigate dynamic processes on a molecular level with sub-millisecond time resolution. Reaction kinetics in the sub-millisecond time range has been achieved using continuous-flow mixers manufactured using micromachining techniques. The time resolution of these devices has previously been limited, in part, by the X-ray beam sizes delivered by typical SAXS beamlines. These limitations can be overcome using optics to focus X-rays to the micrometer size range providing that beam divergence and photon flux suitable for performing SAXS experiments can be maintained. Such micro-SAXS in combination with microfluidic devices would be an attractive probe for time-resolved studies. Here, the development of a high-duty-cycle scanning microsecond-time-resolution SAXS capability, built around the Kirkpatrick–Baez mirror-based microbeam system at the Biophysics Collaborative Access Team (BioCAT) beamline 18ID at the Advanced Photon Source, Argonne National Laboratory, is reported. A detailed description of the microbeam small-angle-scattering instrument, the turbulent flow mixer, as well as the data acquisition and control and analysis software is provided. Results are presented where this apparatus was used to study the folding of cytochrome c. Future prospects for this technique are discussed

Sub-millisecond time-resolved SAXS using a continuous-flow mixer and X-ray microbeam

Energy Technology Data Exchange (ETDEWEB)

Graceffa, Rita, E-mail: rita.graceffa@gmail.com [Illinois Institute of Technology, 3101 South Dearborn, Chicago, IL 60616 (United States); Nobrega, R. Paul [University of Massachusetts Medical School, 364 Plantation Street, LRB 919, Worcester, MA 01605 (United States); Barrea, Raul A. [Illinois Institute of Technology, 3101 South Dearborn, Chicago, IL 60616 (United States); Kathuria, Sagar V. [University of Massachusetts Medical School, 364 Plantation Street, LRB 919, Worcester, MA 01605 (United States); Chakravarthy, Srinivas [Illinois Institute of Technology, 3101 South Dearborn, Chicago, IL 60616 (United States); Bilsel, Osman [University of Massachusetts Medical School, 364 Plantation Street, LRB 919, Worcester, MA 01605 (United States); Irving, Thomas C. [Illinois Institute of Technology, 3101 South Dearborn, Chicago, IL 60616 (United States)

2013-11-01

The development of a high-duty-cycle microsecond time-resolution SAXS capability at the Biophysics Collaborative Access Team beamline (BioCAT) 18ID at the Advanced Photon Source, Argonne National Laboratory, USA, is reported. Small-angle X-ray scattering (SAXS) is a well established technique to probe the nanoscale structure and interactions in soft matter. It allows one to study the structure of native particles in near physiological environments and to analyze structural changes in response to variations in external conditions. The combination of microfluidics and SAXS provides a powerful tool to investigate dynamic processes on a molecular level with sub-millisecond time resolution. Reaction kinetics in the sub-millisecond time range has been achieved using continuous-flow mixers manufactured using micromachining techniques. The time resolution of these devices has previously been limited, in part, by the X-ray beam sizes delivered by typical SAXS beamlines. These limitations can be overcome using optics to focus X-rays to the micrometer size range providing that beam divergence and photon flux suitable for performing SAXS experiments can be maintained. Such micro-SAXS in combination with microfluidic devices would be an attractive probe for time-resolved studies. Here, the development of a high-duty-cycle scanning microsecond-time-resolution SAXS capability, built around the Kirkpatrick–Baez mirror-based microbeam system at the Biophysics Collaborative Access Team (BioCAT) beamline 18ID at the Advanced Photon Source, Argonne National Laboratory, is reported. A detailed description of the microbeam small-angle-scattering instrument, the turbulent flow mixer, as well as the data acquisition and control and analysis software is provided. Results are presented where this apparatus was used to study the folding of cytochrome c. Future prospects for this technique are discussed.

Structural Analysis of Multi-component Amyloid Systems by Chemometric SAXS Data Decomposition

DEFF Research Database (Denmark)

Trillo, Isabel Fatima Herranz; Jensen, Minna Grønning; van Maarschalkerweerd, Andreas

2017-01-01

Formation of amyloids is the hallmark of several neurodegenerative pathologies. Structural investigation of these complex transformation processes poses significant experimental challenges due to the co-existence of multiple species. The additive nature of small-angle X-ray scattering (SAXS) data...... least squares (MCR-ALS) chemometric method. The approach enables rigorous and robust decomposition of synchrotron SAXS data by simultaneously introducing these data in different representations that emphasize molecular changes at different time and structural resolution ranges. The approach has allowed...

Particle size distribution of iron nanomaterials in biological medium by SR-SAXS method

International Nuclear Information System (INIS)

Jing Long; Feng Weiyue; Wang Bing; Wang Meng; Ouyang Hong; Zhao Yuliang; Chai Zhifang; Wang Yun; Wang Huajiang; Zhu Motao; Wu Zhonghua

2009-01-01

A better understanding of biological effects of nanomaterials in organisms requests knowledge of the physicochemical properties of nanomaterials in biological systems. Affected by high concentration salts and proteins in biological medium, nanoparticles are much easy to agglomerate,hence the difficulties in characterizing size distribution of the nanomaterials in biological medium.In this work, synchrotron radiation small angle X-ray scattering(SR-SAXS) was used to determine size distributions of Fe, Fe 2 O 3 and Fe 3 O 4 nanoparticles of various concentrations in PBS and DMEM culture medium. The results show that size distributions of the nanomaterials could perfectly analyzed by SR-SAXS. The SR-SAXS data were not affected by the particle content and types of the dispersion medium.It is concluded that SR-SAXS can be used for size measurement of nanomaterials in unstable dispersion systems. (authors)

BioSAXS Sample Changer: a robotic sample changer for rapid and reliable high-throughput X-ray solution scattering experiments

Energy Technology Data Exchange (ETDEWEB)

Round, Adam, E-mail: around@embl.fr; Felisaz, Franck [European Molecular Biology Laboratory, Grenoble Outstation, 71 Avenue des Martyrs, CS 90181, 38042 Grenoble (France); Université Grenoble Alpes–EMBL–CNRS, 71 Avenue des Martyrs, CS 90181, 38042 Grenoble (France); Fodinger, Lukas; Gobbo, Alexandre [European Molecular Biology Laboratory, Grenoble Outstation, 71 Avenue des Martyrs, CS 90181, 38042 Grenoble (France); Huet, Julien [European Molecular Biology Laboratory, Grenoble Outstation, 71 Avenue des Martyrs, CS 90181, 38042 Grenoble (France); Université Grenoble Alpes–EMBL–CNRS, 71 Avenue des Martyrs, CS 90181, 38042 Grenoble (France); Villard, Cyril [European Molecular Biology Laboratory, Grenoble Outstation, 71 Avenue des Martyrs, CS 90181, 38042 Grenoble (France); Blanchet, Clement E., E-mail: around@embl.fr [EMBL c/o DESY, Notkestrasse 85, 22603 Hamburg (Germany); Pernot, Petra; McSweeney, Sean [ESRF, 6 Rue Jules Horowitz, 38000 Grenoble (France); Roessle, Manfred; Svergun, Dmitri I. [EMBL c/o DESY, Notkestrasse 85, 22603 Hamburg (Germany); Cipriani, Florent, E-mail: around@embl.fr [European Molecular Biology Laboratory, Grenoble Outstation, 71 Avenue des Martyrs, CS 90181, 38042 Grenoble (France); Université Grenoble Alpes–EMBL–CNRS, 71 Avenue des Martyrs, CS 90181, 38042 Grenoble (France)

2015-01-01

A robotic sample changer for solution X-ray scattering experiments optimized for speed and to use the minimum amount of material has been developed. This system is now in routine use at three high-brilliance European synchrotron sites, each capable of several hundred measurements per day. Small-angle X-ray scattering (SAXS) of macromolecules in solution is in increasing demand by an ever more diverse research community, both academic and industrial. To better serve user needs, and to allow automated and high-throughput operation, a sample changer (BioSAXS Sample Changer) that is able to perform unattended measurements of up to several hundred samples per day has been developed. The Sample Changer is able to handle and expose sample volumes of down to 5 µl with a measurement/cleaning cycle of under 1 min. The samples are stored in standard 96-well plates and the data are collected in a vacuum-mounted capillary with automated positioning of the solution in the X-ray beam. Fast and efficient capillary cleaning avoids cross-contamination and ensures reproducibility of the measurements. Independent temperature control for the well storage and for the measurement capillary allows the samples to be kept cool while still collecting data at physiological temperatures. The Sample Changer has been installed at three major third-generation synchrotrons: on the BM29 beamline at the European Synchrotron Radiation Facility (ESRF), the P12 beamline at the PETRA-III synchrotron (EMBL@PETRA-III) and the I22/B21 beamlines at Diamond Light Source, with the latter being the first commercial unit supplied by Bruker ASC.

Additivity, redundancy, and complementarity between structural information from NMR and SAXS data

International Nuclear Information System (INIS)

Kojima, Masaki; Nonaka, Takamasa; Morimoto, Yasumasa; Nakagawa, Takashi; Yanagi, Shigeru; Kihara, Hiroshi

2009-01-01

At present protein structure in solution is determined by restrained molecular dynamics with distance restraints mainly derived from NMR. Although the small-angle X-ray scattering (SAXS) method also confers the structural information, its content is too small to determine the structure by itself. We previously developed a new algorithm that refines the protein structure by restrained molecular dynamics with SAXS constrains. In the present study we performed the protein structure calculation by restrained molecular dynamics with both NMR and SAXS constraints, in order to elucidate the essential structural information that defines the protein architecture. We used RNase T1 as a model protein, which has already been determined by NMR alone. At first we added SAXS constraints (h -1 ) into the original NMR-derived restraints for the calculation. The quality of the structure ensemble was significantly increased. Next we removed the original NMR restraints randomly in order to estimate the redundancy among the NMR-derived information. The essential topology of the resultant structures was hardly changed until the restraints were reduced below the half. Then we added the SAXS constraints into the remaining NMR restraints to expect they could complement the lost structural information. However, the structure was not recovered properly. By removing various types of structural information exclusively from the original NMR data set, we investigated whether the SAXS constraints could complement some kinds of structural information. The results showed that the SAXS could complement the tertiary structure to some extent while it could not secondary structure. (author)

Supramolecular structure of methyl cellulose and lambda- and kappa-carrageenan in water: SAXS study using the string-of-beads model.

Science.gov (United States)

Dogsa, Iztok; Cerar, Jure; Jamnik, Andrej; Tomšič, Matija

2017-09-15

A detailed data analysis utilizing the string-of-beads model was performed on experimental small-angle X-ray scattering (SAXS) curves in a targeted structural study of three, very important, industrial polysaccharides. The results demonstrate the quality of performance for this model on three polymers with quite different thermal structural behavior. Furthermore, they show the advantages of the model used by way of excellent fits in the ranges where the classic approach to the small-angle scattering data interpretation fails and an additional 3D visualization of the model's molecular conformations and anticipated polysaccharide supramolecular structure. The importance of this study is twofold: firstly, the methodology used and, secondly, the structural details of important biopolymers that are widely applicable in practice. Copyright © 2017 Elsevier Ltd. All rights reserved.

SAXS measurements of crystallization in Me PEEK

International Nuclear Information System (INIS)

Barberato, C.; Kellerman, G.; Craievich, A.F.; Torriani, I.L.

1997-01-01

Full text. Preliminary small-angle x-ray scattering (SAXS) measurements on a variety of methyl-substituted poly(aryl ether ether ketone) (Me PEEK) samples have been performed at the D11AA-SAXS beam line of the Brazilian National Synchrotron Light Laboratory (LNLS).Me PEEK is an industrially important thermoplastic material exhibiting crystallization upon annealing at temperatures between 175 and 200 deg C. Differential Scanning Calorimetry (DSC) measurements (Handa Y.P., Roovers, J., Wang, F., Macromolecules 27(19), 551-5516 (1994)) indicate that the presence of supercritical fluids during thermal treatment can have dramatic effects on the melting behavior of Me PEEK when compared to similar data for materials annealed in air. These observations have been made for samples demonstrating no significant differences in the extent of crystallinity suggesting that it is the nature of the crystallites that is affected by the presence of additives during the thermal treatment. In this preliminary study, scattering profiles for three Me PEEK samples (as received, thermally treated in air and thermally treated with supercritical 0.85 CO 2 +C H 3 O H gas) are obtained. The data are analyzed to provide some measure of the variation in crystallite structure between the thermally treated samples. Scattering data obtained in the very small-angle region on the same samples at the High Brilliance Beamline (ID2/BM4) experiments performed by Olivier Diat and M.A. Singh, Dec. 11996) of the European Synchrotron Radiation Facility (ESRF) is combined with the Brazilian National Laboratory on Synchrotron Light (LNLS) data to provide information over 3 decades of scattering angle. This work is part of a larger study of the use of supercritical fluids to control the level and morphology of crystallization in these materials. (author)

Difference structures from time-resolved small-angle and wide-angle x-ray scattering

Science.gov (United States)

Nepal, Prakash; Saldin, D. K.

2018-05-01

Time-resolved small-angle x-ray scattering/wide-angle x-ray scattering (SAXS/WAXS) is capable of recovering difference structures directly from difference SAXS/WAXS curves. It does so by means of the theory described here because the structural changes in pump-probe detection in a typical time-resolved experiment are generally small enough to be confined to a single residue or group in close proximity which is identified by a method akin to the difference Fourier method of time-resolved crystallography. If it is assumed, as is usual with time-resolved structures, that the moved atoms lie within the residue, the 100-fold reduction in the search space (assuming a typical protein has about 100 residues) allows the exaction of the structure by a simulated annealing algorithm with a huge reduction in computing time and leads to a greater resolution by varying the positions of atoms only within that residue. This reduction in the number of potential moved atoms allows us to identify the actual motions of the individual atoms. In the case of a crystal, time-resolved calculations are normally performed using the difference Fourier method, which is, of course, not directly applicable to SAXS/WAXS. The method developed in this paper may be thought of as a substitute for that method which allows SAXS/WAXS (and hence disordered molecules) to also be used for time-resolved structural work.

Synchrotron SAXS studies on morphology formation in a binary blend of poly(ε-caprolactone) homopolymer and poly(ε-caprolactone)-block-polybutadiene copolymer

International Nuclear Information System (INIS)

Akaba, Michiaki; Nojima, Shuichi

2005-01-01

The process of morphology formation in a binary blend of poly(ε-caprolactone) homopolymer (PCL) and poly(ε-caprolactone)-block-polybutadiene copolymer (PCL-b-PB) has been investigated by synchrotron small-angle X-ray scattering (SR-SAXS). This blend shows an UCST-type phase separation and the crystallization of PCL chains (i.e., PCL and PCL blocks in PCL-b-PB) at a same temperature range, so that these two factors may work simultaneously to yield a complicated morphology formation. When the weight fraction of PCL (φ PCL ) is small (φ PCL PCL > 0.8), the blend can directly be quenched into crystallization temperatures without passing through the UCST region. Time-resolved SAXS curves in this case show that overall morphology formation is driven by the crystallization of PCL chains, where a crystallized PCL region always coexists with a crystallized PCL-b-PB region and the volume ratio of two regions is constant throughout. (author)

Location of cholesterol in liposomes by using small-angle X-ray scattering (SAXS) data and the generalized indirect Fourier transformation (GIFT) method.

Science.gov (United States)

Aburai, Kenichi; Ogura, Taku; Hyodo, Ryo; Sakai, Hideki; Abe, Masahiko; Glatter, Otto

2013-01-01

We investigated the location of cholesterol (Chol) in liposomes and its interaction with phospholipids using small-angle x-ray scattering (SAXS) data and applying the generalized indirect Fourier transformation (GIFT) method. The GIFT method has been applied to lamellar liquid crystal systems and it gives quantitative data on bilayer thickness, electron density profile, and membrane flexibility (Caillé parameter). When the GIFT method is applied to the SAXS data of dipalmitoylphosphatidylcholine (DPPC) alone (Chol [-]) or a DPPC/Chol = 7/3 mixed system (Chol [+], molar ratio), change in the bilayer thickness was insignificant in both systems. However, the electron density for the Chol (+) system was higher than that for the Chol (-) system at the location of hydrophilic groups of phospholipids, and whereas Caillé parameter value increased with temperature for the Chol (-) system, no significant change with temperature was observed in the Caillé parameter for the Chol (+) system. These results indicated that Chol is located in the vicinity of the hydrophilic group of the phospholipids and constricts the packing of the acyl chain of phospholipids in the bilayer.

Investigation of the porous structure of glassy carbon by SAXS - an application of synchrotron radiation

Energy Technology Data Exchange (ETDEWEB)

Braun, A; Baertsch, M; Schnyder, B; Koetz, R; Haas, O [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

1999-08-01

The porous structure of Electrochemical Double Layer Capacitor (EDC) Electrodes was investigated using Small Angle X-ray Scattering (SAXS), assuming logarithmically normal distributed micropores. (author) 2 figs., 1 ref.

SAXS investigations on lipid membranes under osmotic stress

Energy Technology Data Exchange (ETDEWEB)

Rubim, R.L.; Vieira, V.; Gerbelli, B.B.; Teixeira da Silva, E.R.; Oliveira, C.L.P.; Oliveira, E.A. [Universidade de Sao Paulo (USP), Sao Paulo, SP (Brazil)

2012-07-01

Full text: In this work we, experimentally, investigate the interactions between lipid bilayers. A structural characterization is performed by small angle x-ray scattering (SAXS) on multilamellar systems under known osmotic pressure. Changes in the composition of membranes can modify their mechanical properties and structural parameters, like the flexibility of these membranes, which plays a key role on the determination of the tridimensional organization of bilayers. The membranes are composed of soya lecithin, where the major component is DPPC (Dipalmitoylphosphatidylcholine), and fatty acids are incorporated to the membrane in different concentrations, in order to turn the membrane more fluid. The membranes are inserted in a solution of PVP [poly(vinyl-pyrrolidone) - 40000] and the polymer will apply an osmotic pressure on them. The osmotic pressure is controlled by preparing PVP solutions of desired composition and, as we know the concentration of polymer in solution, we can obtain the intensity of the osmotic pressure. SAXS experiments were done in order to determine the distance between the bilayer. From the position of the Bragg peaks, the lamellar periodicity (the thickness of the membranes plus their distance of separation) was determined. Using theoretical model for the form and structure factors we fitted those experimental data and determined the thickness of the membranes. The distance between the membranes was controlled by the osmotic pressure (P) applied to the membranes and, for a given pressure, we determine the distance between the bilayers (a) on equilibrium. The experimental curve P(a) is theoretically described by the different contributions from van der Waals, hydration and fluctuation forces. From the fitting of experimental curves, relevant parameters characterizing the strength of the different interactions are obtained, such as Hamaker and rigidity constant [2, 3]. We observe that the separation between the bilayers on equilibrium is

BioSAXS Sample Changer: a robotic sample changer for rapid and reliable high-throughput X-ray solution scattering experiments.

Science.gov (United States)

Round, Adam; Felisaz, Franck; Fodinger, Lukas; Gobbo, Alexandre; Huet, Julien; Villard, Cyril; Blanchet, Clement E; Pernot, Petra; McSweeney, Sean; Roessle, Manfred; Svergun, Dmitri I; Cipriani, Florent

2015-01-01

Small-angle X-ray scattering (SAXS) of macromolecules in solution is in increasing demand by an ever more diverse research community, both academic and industrial. To better serve user needs, and to allow automated and high-throughput operation, a sample changer (BioSAXS Sample Changer) that is able to perform unattended measurements of up to several hundred samples per day has been developed. The Sample Changer is able to handle and expose sample volumes of down to 5 µl with a measurement/cleaning cycle of under 1 min. The samples are stored in standard 96-well plates and the data are collected in a vacuum-mounted capillary with automated positioning of the solution in the X-ray beam. Fast and efficient capillary cleaning avoids cross-contamination and ensures reproducibility of the measurements. Independent temperature control for the well storage and for the measurement capillary allows the samples to be kept cool while still collecting data at physiological temperatures. The Sample Changer has been installed at three major third-generation synchrotrons: on the BM29 beamline at the European Synchrotron Radiation Facility (ESRF), the P12 beamline at the PETRA-III synchrotron (EMBL@PETRA-III) and the I22/B21 beamlines at Diamond Light Source, with the latter being the first commercial unit supplied by Bruker ASC.

In situ study starch gelatinization under ultra-high hydrostatic pressure using synchrotron SAXS

KAUST Repository

Yang, Zhi; Gu, Qinfen; Lam, Elisa; Tian, Feng; Chaieb, Saharoui; Hemar, Yacine

2015-01-01

The gelatinization of waxy (very low amylose) corn and potato starches by high hydrostatic pressure (HHP) (up to ∼1 GPa) was investigated in situ using synchrotron small-angle X-ray scattering (SAXS) on samples held in a diamond anvil cell (DAC

Fibrinogen species as resolved by HPLC-SAXS data processing within the UltraScan Solution Modeler (US-SOMO) enhanced SAS module.

Science.gov (United States)

Brookes, Emre; Pérez, Javier; Cardinali, Barbara; Profumo, Aldo; Vachette, Patrice; Rocco, Mattia

2013-12-01

Fibrinogen is a large heterogeneous aggregation/degradation-prone protein playing a central role in blood coagulation and associated pathologies, whose structure is not completely resolved. When a high-molecular-weight fraction was analyzed by size-exclusion high-performance liquid chromatography/small-angle X-ray scattering (HPLC-SAXS), several composite peaks were apparent and because of the stickiness of fibrinogen the analysis was complicated by severe capillary fouling. Novel SAS analysis tools developed as a part of the UltraScan Solution Modeler ( US-SOMO ; http://somo.uthscsa.edu/), an open-source suite of utilities with advanced graphical user interfaces whose initial goal was the hydrodynamic modeling of biomacromolecules, were implemented and applied to this problem. They include the correction of baseline drift due to the accumulation of material on the SAXS capillary walls, and the Gaussian decomposition of non-baseline-resolved HPLC-SAXS elution peaks. It was thus possible to resolve at least two species co-eluting under the fibrinogen main monomer peak, probably resulting from in-column degradation, and two others under an oligomers peak. The overall and cross-sectional radii of gyration, molecular mass and mass/length ratio of all species were determined using the manual or semi-automated procedures available within the US-SOMO SAS module. Differences between monomeric species and linear and sideways oligomers were thus identified and rationalized. This new US-SOMO version additionally contains several computational and graphical tools, implementing functionalities such as the mapping of residues contributing to particular regions of P ( r ), and an advanced module for the comparison of primary I ( q ) versus q data with model curves computed from atomic level structures or bead models. It should be of great help in multi-resolution studies involving hydrodynamics, solution scattering and crystallographic/NMR data.

Study of macromolecules of biological interest by x-ray scattering

International Nuclear Information System (INIS)

Beltran, J.R.

1987-08-01

A brief review of the SAXS theory and experimental is presented. Solutions of crotamine, crotoxine, phospholipase and crotapotine are studied in several concentrations, extrapolated to infinite dilution and the results obtained are presented. The general shape of these proteins were also evaluated taking in consideration the relationships between the respective surface areas and volumes. A model was then devised taking into account the information available relative to aminoacid sequence, predicted secondary structure and spectroscopic data and its P(r) was calculated using the MULTIBODY program (Glatter (1980)). The P(r) curve is this way obtained showed a considerable agreement with the P(r) obtained resing the scattering curve. (author)

SAXS-WAXS studies of the low-resolution structure in solution of xylose/glucose isomerase from Streptomyces rubiginosus

Science.gov (United States)

Kozak, Maciej; Taube, Michał

2009-10-01

The structure and conformation of molecule of xylose/glucose isomerase from Streptomyces rubiginosus in solution (at pH 6 and 7.6; with and without the substrate) has been studied by small- and wide-angle scattering of synchrotron radiation (SAXS-WAXS). On the basis of the SAXS-WAXS data, the low-resolution structure in solution has been reconstructed using ab inito methods. A comparison of the models of glucose isomerase shows only small differences between the model in solution and the crystal structure.

Small angle neutron scattering and small angle X-ray scattering ...

Indian Academy of Sciences (India)

Abstract. The morphology of carbon nanofoam samples comprising platinum nanopar- ticles dispersed in the matrix was characterized by small angle neutron scattering (SANS) and small angle X-ray scattering (SAXS) techniques. Results show that the structure of pores of carbon matrix exhibits a mass (pore) fractal nature ...

Preliminary study of human breast tissue using synchrotron radiation combining WAXS and SAXS techniques

International Nuclear Information System (INIS)

Conceicao, A.L.C.; Antoniassi, M.; Poletti, M.E.; Caldas, L.V.E.

2010-01-01

Using synchrotron radiation, we combined simultaneously wide angle X-ray scattering (WAXS) and small angle X-ray scattering (SAXS) techniques to obtain the scattering profiles of normal and neoplastic breast tissues samples at the momentum transfer range 6.28 nm -1 ≤Q(=4π.sin(θ/2)/λ)≤50.26 nm -1 and 0.15 nm -1 ≤Q≤1.90 nm -1 , respectively. The results obtained show considerable differences between the scattering profiles of these tissues. We verified that the combination of some parameters (ratio between glandular and adipose peak intensity and third-order axial peak intensity) extracted from scattering profiles can be used for identifying breast cancer.

Six-dimensional real and reciprocal space small-angle X-ray scattering tomography.

Science.gov (United States)

Schaff, Florian; Bech, Martin; Zaslansky, Paul; Jud, Christoph; Liebi, Marianne; Guizar-Sicairos, Manuel; Pfeiffer, Franz

2015-11-19

When used in combination with raster scanning, small-angle X-ray scattering (SAXS) has proven to be a valuable imaging technique of the nanoscale, for example of bone, teeth and brain matter. Although two-dimensional projection imaging has been used to characterize various materials successfully, its three-dimensional extension, SAXS computed tomography, poses substantial challenges, which have yet to be overcome. Previous work using SAXS computed tomography was unable to preserve oriented SAXS signals during reconstruction. Here we present a solution to this problem and obtain a complete SAXS computed tomography, which preserves oriented scattering information. By introducing virtual tomography axes, we take advantage of the two-dimensional SAXS information recorded on an area detector and use it to reconstruct the full three-dimensional scattering distribution in reciprocal space for each voxel of the three-dimensional object in real space. The presented method could be of interest for a combined six-dimensional real and reciprocal space characterization of mesoscopic materials with hierarchically structured features with length scales ranging from a few nanometres to a few millimetres--for example, biomaterials such as bone or teeth, or functional materials such as fuel-cell or battery components.

A posteriori determination of the useful data range for small-angle scattering experiments on dilute monodisperse systems.

Science.gov (United States)

Konarev, Petr V; Svergun, Dmitri I

2015-05-01

Small-angle X-ray and neutron scattering (SAXS and SANS) experiments on solutions provide rapidly decaying scattering curves, often with a poor signal-to-noise ratio, especially at higher angles. On modern instruments, the noise is partially compensated for by oversampling, thanks to the fact that the angular increment in the data is small compared with that needed to describe adequately the local behaviour and features of the scattering curve. Given a (noisy) experimental data set, an important question arises as to which part of the data still contains useful information and should be taken into account for the interpretation and model building. Here, it is demonstrated that, for monodisperse systems, the useful experimental data range is defined by the number of meaningful Shannon channels that can be determined from the data set. An algorithm to determine this number and thus the data range is developed, and it is tested on a number of simulated data sets with various noise levels and with different degrees of oversampling, corresponding to typical SAXS/SANS experiments. The method is implemented in a computer program and examples of its application to analyse the experimental data recorded under various conditions are presented. The program can be employed to discard experimental data containing no useful information in automated pipelines, in modelling procedures, and for data deposition or publication. The software is freely accessible to academic users.

Time-Resolved WAXD and SAXS Investigations on Butyl Branched Alkane at Elevated Pressures

NARCIS (Netherlands)

Rastogi, A.; Hobbs, J.K.; Rastogi, S.

2002-01-01

The crystallization behavior and the morphological aspect of the butyl branched alkane C96H193CH(C4H9)C94H189 have been investigated using time-resolved wide-angle X-ray diffraction (WAXD) and small-angle X-ray scattering (SAXS) at atmospheric and elevated pressures. The solution crystallized sample

High-throughput and automated SAXS/USAXS experiment for industrial use at BL19B2 in SPring-8

Energy Technology Data Exchange (ETDEWEB)

Osaka, Keiichi, E-mail: k-osaka@spring8.or.jp; Inoue, Daisuke; Sato, Masugu; Sano, Norimichi [Industrial Application Division, Japan Synchrotron Radiation Research Institute (JASRI/SPring-8), 1-1-1, Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5198 (Japan); Matsumoto, Takuya; Taniguchi, Yosuke [SPring-8 Service Co., Ltd., 1-20-5, Kouto, Shingu, Tatsuno, Hyogo 679-5165 (Japan)

2016-07-27

A highly automated system combining a sample transfer robot with focused SR beam has been established for small-angle and ultra small-angle X-ray scattering (SAXS/USAXS) measurement at BL19B2 for industrial use of SPring-8. High-throughput data collection system can be realized by means of X-ray beam of high photon flux density concentrated by a cylindrical mirror, and a two-dimensional pixel detector PILATUS-2M. For SAXS measurement, we can obtain high-quality data within 1 minute for one exposure using this system. The sample transfer robot has a capacity of 90 samples with a large variety of shapes. The fusion of high-throughput and robotic system has enhanced the usability of SAXS/USAXS capability for industrial application.

Effect of interparticle interactions on size determination of zirconia and silica based systems – A comparison of SAXS, DLS, BET, XRD and TEM

Science.gov (United States)

Pabisch, Silvia; Feichtenschlager, Bernhard; Kickelbick, Guido; Peterlik, Herwig

2012-01-01

The aim of this work is a systematic comparison of size characterisation methods for two completely different model systems of oxide nanoparticles, i.e. amorphous spherical silica and anisotropic facet-shaped crystalline zirconia. Size and/or size distribution were determined in a wide range from 5 to 70 nm using small-angle X-ray scattering (SAXS), dynamic light scattering (DLS), nitrogen sorption (BET), X-ray diffraction (XRD) and transmission electron microscopy (TEM). A nearly perfect coincidence was observed only for SAXS and TEM for both types of particles. For zirconia nanoparticles considerable differences between different measurement methods were observed. PMID:22347721

SAXS determination of the structural periodicity of thermoplastic polyurethane reinforced with cellulose nanocrystals; Determinacao da perodicidade estrutural de poliuretano termoplastico reforcado com nanocristais de celulose por SAXS

Energy Technology Data Exchange (ETDEWEB)

Prataviera, Rogerio; Bretas, Rosario E.S.; Lucas, Alessandra de A., E-mail: lucas@ufscar.br [Universidade Federal de Sao Carlos, (UFSCar), Sao Carlos, SP (Brazil); Poullet, Eric; Averous, Luc [Universidade de Strasbourg, Strasbourg (France)

2015-07-01

In this work, casting films were obtained from TPU reinforced with cellulose nanocrystals. The structural nano periodicity of these system was evaluated by Small Angle X-Ray Scattering, SAXS. The results indicated that the used TPU has a atypical phase separated morphology of rigid and soft segments, being observed 3 different distances them, probably due to the large polyol polyester molecule derived from colza oil used in the TPU synthesis. (author)

A4F-SAXS online-coupling for the investigation of nanoparticles and polymers; Die A4F-SAXS Online-Kopplung zur Untersuchung von Nanopartikeln und Polymeren

Energy Technology Data Exchange (ETDEWEB)

Knappe, Patrick

2012-07-13

In the present thesis the online-coupling of asymmetric flow field-flow fractionation (A4F) with small-angle X-ray scattering (SAXS) as a versatile analytical tool is introduced and applied to current challenges in nanoparticle analysis as well as to model systems of technically relevant polymers. The A4F provides size separation of sample solutions and suspensions. Due to the separation principle only low shear forces are applied which appear in competing methods. Therefore, this method allows processing of very sensitive sample materials. SAXS allows non-destructive probing of nanoscale structures in the range of about one to one hundred nanometers. By coupling with A4F, the complexity of sample systems with broad size distributions, which are therefore frequently hard to characterize, is reduced significantly prior to further analysis. Applying this approach, detailed information about sample properties can be gained accurately with respect to the shape, size and size distribution of particles or conformation of macromolecules in short time. Addition of a dynamic light scattering detector to the setup allows a further conclusion. With the latter, a nanoparticles suspension was characterized rapidly and with good precision with respect to the core properties of the particles as well as the thickness of the stabilizer's shell in a single online run. These parameters are important when dealing not only with functionality but also with the bioavailability or toxicity of nanoparticles. This methodology was also successfully applied to polymer systems for the first time, namely poly(vinyl pyrrolidone)s as well as strong and weak polyelectrolytes. Additionally, due to the applied separation method samples with broad molar mass distributions were processable which otherwise tend to interfere with stationary phase-based chromatography. Furthermore, using SAXS, structural properties can be resolved from smaller polymer size-fractions which are hardly accessible with

A4F-SAXS online-coupling for the investigation of nanoparticles and polymers; Die A4F-SAXS Online-Kopplung zur Untersuchung von Nanopartikeln und Polymeren

Energy Technology Data Exchange (ETDEWEB)

Knappe, Patrick

2012-07-13

In the present thesis the online-coupling of asymmetric flow field-flow fractionation (A4F) with small-angle X-ray scattering (SAXS) as a versatile analytical tool is introduced and applied to current challenges in nanoparticle analysis as well as to model systems of technically relevant polymers. The A4F provides size separation of sample solutions and suspensions. Due to the separation principle only low shear forces are applied which appear in competing methods. Therefore, this method allows processing of very sensitive sample materials. SAXS allows non-destructive probing of nanoscale structures in the range of about one to one hundred nanometers. By coupling with A4F, the complexity of sample systems with broad size distributions, which are therefore frequently hard to characterize, is reduced significantly prior to further analysis. Applying this approach, detailed information about sample properties can be gained accurately with respect to the shape, size and size distribution of particles or conformation of macromolecules in short time. Addition of a dynamic light scattering detector to the setup allows a further conclusion. With the latter, a nanoparticles suspension was characterized rapidly and with good precision with respect to the core properties of the particles as well as the thickness of the stabilizer's shell in a single online run. These parameters are important when dealing not only with functionality but also with the bioavailability or toxicity of nanoparticles. This methodology was also successfully applied to polymer systems for the first time, namely poly(vinyl pyrrolidone)s as well as strong and weak polyelectrolytes. Additionally, due to the applied separation method samples with broad molar mass distributions were processable which otherwise tend to interfere with stationary phase-based chromatography. Furthermore, using SAXS, structural properties can be resolved from smaller polymer size-fractions which are hardly accessible with other

The New BeppoSAX Observation of the Brightest X-Ray Quasar at Redshift

Science.gov (United States)

Nicastro, Fabrizio; Oliversen, Ronald J. (Technical Monitor)

2001-01-01

This grant was to support the reduction and analysis of our approved SAX observation of the high redshift (z=3.2) blazar PKS 2126-158. This is the brightest quasar at z greater than 3 and has been intensively studied in X-ray, since the first Einstein detection. In 1994 Elvis et al., discovered a strong low energy cutoff in this object, which could imply either quasar frame photoelectric absorption by a column of 0.8-2.7 x 1e22 cm-2 cold gas, or a lower column of cold gas at z=0. Subsequent ASCA observations of this object, could not definitely address this issue, nor could establish whether the curvature of the low energy portion of the spectrum was due to pure photoelectric absorption (considerably exceeding the Galactic value along the line of sight) or to an intrinsic continuum curvature. We proposed to observe PKS 2126-158 with BeppoSAX, to try to solve this puzzle (thanks to the broadband of BeppoSAX: 0.1-250 keV). PKS 2126 was observed by BeppoSAX on May 1999, with a MECS exposure of 100 ks. We have reduced and analyzed the BeppoSAX data, and compared them with a Chandra ACIS observation of the same object, taken only 6 months apart (Nov. 1999). We have recently finished to write a paper on the BeppoSAX data only, that concentrate on the properties of the X-ray absorber, which is highly requested by our SAX data, independently on the continuum model adopted. The paper (P.I.F. Fiore) will be submitted to APJ in the next few days. A second paper on the combined BeppoSAX and Chandra data, and based on the broad band spectral energy distribution of this quasar, is currently in preparation. Our main results, on the X-ray absorber, are: (a) the presence of an X-ray absorber is confirmed, indipendently on the continuum adopted (simple power law, or curved continuum); (b) if the absorber is not significantly ionized, then the BeppoSAX data do prefer a low redshift absorber; (c) if the gas is ionized, then it can be located in the quasar environment, but its metal

Integrative structural modeling with small angle X-ray scattering profiles

Directory of Open Access Journals (Sweden)

Schneidman-Duhovny Dina

2012-07-01

Full Text Available Abstract Recent technological advances enabled high-throughput collection of Small Angle X-ray Scattering (SAXS profiles of biological macromolecules. Thus, computational methods for integrating SAXS profiles into structural modeling are needed more than ever. Here, we review specifically the use of SAXS profiles for the structural modeling of proteins, nucleic acids, and their complexes. First, the approaches for computing theoretical SAXS profiles from structures are presented. Second, computational methods for predicting protein structures, dynamics of proteins in solution, and assembly structures are covered. Third, we discuss the use of SAXS profiles in integrative structure modeling approaches that depend simultaneously on several data types.

SAXS and SANS studies of surfactants and reverse micelles in supercritical CO2

International Nuclear Information System (INIS)

Londono, J.D.; Dharmapurikar, R.S.; Wignall, G.D.; Cochran, H.D.

1997-01-01

Surfactants promise to extend the applicability of supercritical CO 2 (SC-CO 2 ) to processing of insoluble materials such as polymers and aqueous systems. In this short paper the authors summarize the techniques for studying surfactants and reverse micelles in SC-CO 2 using SAXS and SANS; they will describe the scattering instruments and the pressure cells for conducting these studies; they will describe the types of measurement that yield the desired characterizations; they will describe the methods of data analysis and interpretation; and they will provide illustrative results from this laboratory. Industry seeks to replace common organic solvents now used in many reaction and separation processes; SC-CO 2 is a potential solvent substitute widely favored by both government and industry. The currently available surfactants are limited in number and performance. In ongoing work the authors are coupling their SAXS and SANS scattering studies with complementary molecular simulations in efforts to understand, at a molecular level, what surfactant characteristics lead to improved performance. They hope that superior surfactants for use in SC-CO 2 can be designed and synthesized based on this new level of understanding

In situ study starch gelatinization under ultra-high hydrostatic pressure using synchrotron SAXS

KAUST Repository

Yang, Zhi

2015-12-13

The gelatinization of waxy (very low amylose) corn and potato starches by high hydrostatic pressure (HHP) (up to ∼1 GPa) was investigated in situ using synchrotron small-angle X-ray scattering (SAXS) on samples held in a diamond anvil cell (DAC). The starch pastes, made by mixing starch and water in a 1:1 ratio (by weight), were pressurized and measured at room temperature. During HHP, both SAXS peak areas (corresponding to the lamellar phase) of waxy corn and potato starches decreased suggesting the starch gelatinization increases with increasing pressure. As pressure increased, lamellar peak broadened and the power law exponent increased in low q region. 1D linear correlation function was further employed to analyse SAXS data. For both waxy potato and waxy corn starches, the long period length and the average thickness of amorphous layers decreased when the pressure increased. While for both of waxy starches, the thickness of the crystalline layer first increased, then decreased when the pressure increased. The former is probably due to the out-phasing of starch molecules, and the latter is due to the water penetrating into the crystalline region during gelatinization and to pressure induced compression.

Characterization of size and morphology of ZnO and Fe2O3 nanoparticles in dispersive media by SAXS

International Nuclear Information System (INIS)

Wang Bing; Wang Meng; Zhu Motao; Zhao Yuliang; Wu Zhonghua

2007-01-01

The size and shape of ZnO and Fe 2 O 3 nano-particles in 1% sodium carboxy methyl cellulose were measured by small-angle X-ray scattering (SAXS) of synchrotron radiation. Compared with the TEM results, the SAXS results indicated that the ZnO and Fe 2 O 3 nano-particles in 1% sodium carboxy methyl cellulose were agglomerated. However, the size and shape of the agglomerated particles were almost unchanged along with the increase of particle concentration, indicating that the particles in 1% sodium carboxy methyl cellulose were stable. (authors)

SAXS and EXAFS studies of ion beam synthesized Au nanocrystals

International Nuclear Information System (INIS)

Kluth, P.; Johannessen, B.; Cookson, D.J.; Foran, G.J.; Ridgway, M.C.

2006-01-01

We have used small-angle X-ray scattering (SAXS) and extended X-ray absorption fine structure (EXAFS) spectroscopy to investigate Au nanocrystals (NCs) fabricated by high dose ion implantation into thin SiO 2 and subsequent annealing at different temperatures. Size distributions were determined from SAXS and structural parameters were extracted from EXAFS measurements, the latter analyzed as a function of NC size. Increasing implantation dose leads to an increasing average NC size and broadening of the size distribution. A significant size-dependent bond length contraction with respect to bulk material was observed. For samples annealed at 1100 deg. C our analysis suggests that an increased structural disorder is predominantly located at the NC surface. Post-implantation annealing at temperatures of 500 deg. C and 800 deg. C for 1 h in forming gas had no detectable influence on the NC size distribution, however, a significant influence on the structural parameters, in particular increased disorder was observed. This is potentially the result of stress induced disorder due to the different thermal expansion of the NC and matrix materials

Theory of near-critical-angle scattering from a curved interface

International Nuclear Information System (INIS)

Fiedler-Ferrari, N.; Nussenzveig, H.M.; Wiscombe, W.J.

1990-01-01

A new type of diffraction effect, different from the standard semiclassical ones (rainbow, glory, forward peak, orbiting), takes place near the critical angle for total reflection at a curved interface between two homogeneous media. A theoretical treatment of this new effects is given for Mie scattering, e.g., light scattering by an air bubble in water; it can readily be extended to more general curved interface problems in a variety of different fields (quantum mechanics, acoustics, seismic waves). The relatively slowly-varying Mie diffraction pattern associated with near-critical scattering is obscured by rapid fine-structure oscillations due to interference with unrelated farside contributions. These contributions are evaluated and subtracted from the Mie amplitudes to yield the relevant nearside effects. A zero-order transitional CAM (complex angular momentum) approximation to the nearside amplitude is developed. The most important contributions arise from partial and total reflection, represented by two new diffraction integrals, designated Fresnel-Fock and Pearcey-Fock respectively. Also discussed are the WKB approximation, a known physical optics approximation and a new modified version of this approximation: they are compared with the exact nearside Mie amplitude obtained by numerical partial-wave summation, at scatterer size parameters (circumference/wavelength) ranging from 1,000 to 10,000. (author)

SAXS determination of the structural periodicity of thermoplastic polyurethane reinforced with cellulose nanocrystals

International Nuclear Information System (INIS)

Prataviera, Rogerio; Bretas, Rosario E.S.; Lucas, Alessandra de A.; Poullet, Eric; Averous, Luc

2015-01-01

In this work, casting films were obtained from TPU reinforced with cellulose nanocrystals. The structural nano periodicity of these system was evaluated by Small Angle X-Ray Scattering, SAXS. The results indicated that the used TPU has a atypical phase separated morphology of rigid and soft segments, being observed 3 different distances them, probably due to the large polyol polyester molecule derived from colza oil used in the TPU synthesis. (author)

Ambiguity assessment of small-angle scattering curves from monodisperse systems.

Science.gov (United States)

Petoukhov, Maxim V; Svergun, Dmitri I

2015-05-01

A novel approach is presented for an a priori assessment of the ambiguity associated with spherically averaged single-particle scattering. The approach is of broad interest to the structural biology community, allowing the rapid and model-independent assessment of the inherent non-uniqueness of three-dimensional shape reconstruction from scattering experiments on solutions of biological macromolecules. One-dimensional scattering curves recorded from monodisperse systems are nowadays routinely utilized to generate low-resolution particle shapes, but the potential ambiguity of such reconstructions remains a major issue. At present, the (non)uniqueness can only be assessed by a posteriori comparison and averaging of repetitive Monte Carlo-based shape-determination runs. The new a priori ambiguity measure is based on the number of distinct shape categories compatible with a given data set. For this purpose, a comprehensive library of over 14,000 shape topologies has been generated containing up to seven beads closely packed on a hexagonal grid. The computed scattering curves rescaled to keep only the shape topology rather than the overall size information provide a `scattering map' of this set of shapes. For a given scattering data set, one rapidly obtains the number of neighbours in the map and the associated shape topologies such that in addition to providing a quantitative ambiguity measure the algorithm may also serve as an alternative shape-analysis tool. The approach has been validated in model calculations on geometrical bodies and its usefulness is further demonstrated on a number of experimental X-ray scattering data sets from proteins in solution. A quantitative ambiguity score (a-score) is introduced to provide immediate and convenient guidance to the user on the uniqueness of the ab initio shape reconstruction from the given data set.

A new interpretation of SAXS peaks in sulfonated poly(ether ether ketone) (sPEEK) membranes for fuel cells.

Science.gov (United States)

Mendil-Jakani, H; Zamanillo Lopez, I; Legrand, P M; Mareau, V H; Gonon, L

2014-06-21

The structure of a commercial sulfonated poly(ether ether ketone) (sPEEK) membrane was analyzed by Small-Angle X-Ray Scattering (SAXS) for different water uptakes obtained after immersion in liquid water at various temperatures. For low membrane swelling, the SAXS profile displays only a wide-angle peak in the 0.2-0.3 Å(-1) region. As the membrane swells, two supplementary correlation peaks arise and shift towards small angles, which are the signature of a structural evolution of the membrane, whereas the wide angle peak remains stable. The SAXS spectra of sPEEK membranes can thus display three correlation peaks simultaneously. Therefore we propose a new interpretation of these SAXS spectra which conclude that the two small angle peaks are attributed to the so-called matrix and ionomer peaks and the wide-angle peak is ascribed to the mean separation distance between sulfonic acid groups grafted onto the polymer backbone. This peak attribution implies that the sPEEK nano-phase separation is triggered by an immersion in hot water (ionomer peak apparition). Our new peak attribution was confirmed by studying the impact of temperature, electron density contrast and ionic exchange capacity.

Small-angle x-ray scattering in amorphous silicon: A computational study

Science.gov (United States)

Paudel, Durga; Atta-Fynn, Raymond; Drabold, David A.; Elliott, Stephen R.; Biswas, Parthapratim

2018-05-01

We present a computational study of small-angle x-ray scattering (SAXS) in amorphous silicon (a -Si) with particular emphasis on the morphology and microstructure of voids. The relationship between the scattering intensity in SAXS and the three-dimensional structure of nanoscale inhomogeneities or voids is addressed by generating large high-quality a -Si networks with 0.1%-0.3% volume concentration of voids, as observed in experiments using SAXS and positron annihilation spectroscopy. A systematic study of the variation of the scattering intensity in the small-angle scattering region with the size, shape, number density, and the spatial distribution of the voids in the networks is presented. Our results suggest that the scattering intensity in the small-angle region is particularly sensitive to the size and the total volume fraction of the voids, but the effect of the geometry or shape of the voids is less pronounced in the intensity profiles. A comparison of the average size of the voids obtained from the simulated values of the intensity, using the Guinier approximation and Kratky plots, with that of the same from the spatial distribution of the atoms in the vicinity of void surfaces is presented.

Preparing Monodisperse Macromolecular Samples for Successful Biological Small-Angle X-ray and Neutron Scattering Experiments

Science.gov (United States)

Jeffries, Cy M.; Graewert, Melissa A.; Blanchet, Clément E.; Langley, David B.; Whitten, Andrew E.; Svergun, Dmitri I

2017-01-01

Small-angle X-ray and neutron scattering (SAXS and SANS) are techniques used to extract structural parameters and determine the overall structures and shapes of biological macromolecules, complexes and assemblies in solution. The scattering intensities measured from a sample contain contributions from all atoms within the illuminated sample volume including the solvent and buffer components as well as the macromolecules of interest. In order to obtain structural information, it is essential to prepare an exactly matched solvent blank so that background scattering contributions can be accurately subtracted from the sample scattering to obtain the net scattering from the macromolecules in the sample. In addition, sample heterogeneity caused by contaminants, aggregates, mismatched solvents, radiation damage or other factors can severely influence and complicate data analysis so it is essential that the samples are pure and monodisperse for the duration of the experiment. This Protocol outlines the basic physics of SAXS and SANS and reveals how the underlying conceptual principles of the techniques ultimately ‘translate’ into practical laboratory guidance for the production of samples of sufficiently high quality for scattering experiments. The procedure describes how to prepare and characterize protein and nucleic acid samples for both SAXS and SANS using gel electrophoresis, size exclusion chromatography and light scattering. Also included are procedures specific to X-rays (in-line size exclusion chromatography SAXS) and neutrons, specifically preparing samples for contrast matching/variation experiments and deuterium labeling of proteins. PMID:27711050

Water Stress Scatters Nitrogen Dilution Curves in Wheat

Directory of Open Access Journals (Sweden)

Marianne Hoogmoed

2018-04-01

Full Text Available Nitrogen dilution curves relate a crop’s critical nitrogen concentration (%Nc to biomass (W according to the allometric model %Nc = a W-b. This model has a strong theoretical foundation, and parameters a and b show little variation for well-watered crops. Here we explore the robustness of this model for water stressed crops. We established experiments to examine the combined effects of water stress, phenology, partitioning of biomass, and water-soluble carbohydrates (WSC, as driven by environment and variety, on the %Nc of wheat crops. We compared models where %Nc was plotted against biomass, growth stage and thermal time. The models were similarly scattered. Residuals of the %Nc - biomass model at anthesis were positively related to biomass, stem:biomass ratio, Δ13C and water supply, and negatively related to ear:biomass ratio and concentration of WSC. These are physiologically meaningful associations explaining the scatter of biomass-based dilution curves. Residuals of the thermal time model showed less consistent associations with these variables. The biomass dilution model developed for well-watered crops overestimates nitrogen deficiency of water-stressed crops, and a biomass-based model is conceptually more justified than developmental models. This has implications for diagnostic and modeling. As theory is lagging, a greater degree of empiricism might be useful to capture environmental, chiefly water, and genotype-dependent traits in the determination of critical nitrogen for diagnostic purposes. Sensitivity analysis would help to decide if scaling nitrogen dilution curves for crop water status, and genotype-dependent parameters are needed.

μ-PIXE and SAXS studies at the bone-cartilage interface

International Nuclear Information System (INIS)

Kaabar, W.; Gundogdu, O.; Laklouk, A.; Bunk, O.; Pfeiffer, F.; Farquharson, M.J.; Bradley, D.A.

2010-01-01

Micro Proton Induced X-ray Emission (μ-PIXE) analysis has been employed herein in investigating and quantifying the distribution of a number of essential elements in thin human diseased articular cartilage sections affected by osteoarthritis (OA). Various cations Ca, P and Zn have been reported to play an important role both in the normal growth and remodelling of articular cartilage and subchondral bone as well as in the degenerative and inflammatory processes associated with the disease; they act as co-factors of a class of enzymes known as metalloproteinases which are believed to be active during the initiation, progress and remodelling processes associated with osteoarthritis. Other important enzymes such as alkaline phosphatase are associated with cartilage mineralization. Synchrotron radiation X-ray fluorescence (SR-XRF) for mapping of elemental distributions in bone and cartilage has also been employed by the present group and others. In the current investigations using the cSAXS beamline at the Swiss light source, Small-Angle X-ray Scattering (SAXS) was carried out on decalcified human articular cartilage to explore the structural and organizational changes of collagen networks in diseased articular cartilage.

{mu}-PIXE and SAXS studies at the bone-cartilage interface

Energy Technology Data Exchange (ETDEWEB)

Kaabar, W. [Department of Physics, University of Surrey, Guildford GU2 7XH (United Kingdom)], E-mail: w.kaabar@surrey.ac.uk; Gundogdu, O. [Umuttepe Campus, University of Kocaeli, 41380, Kocaeli (Turkey); Laklouk, A. [Food Science Department, Al-Fateh Unversity, Tripoli (Libyan Arab Jamahiriya); Bunk, O. [Swiss Light Source, Paul Scherrer Institute, 5232 Villigen (Switzerland); Pfeiffer, F. [Swiss Light Source, Paul Scherrer Institute, 5232 Villigen (Switzerland); Ecole Polytechnique Federale de Lausanne, 1015 Lausanne (Switzerland); Farquharson, M.J. [Department of Radiography, City University, London EC1V OHB (United Kingdom); Bradley, D.A. [Department of Physics, University of Surrey, Guildford GU2 7XH (United Kingdom)

2010-04-15

Micro Proton Induced X-ray Emission ({mu}-PIXE) analysis has been employed herein in investigating and quantifying the distribution of a number of essential elements in thin human diseased articular cartilage sections affected by osteoarthritis (OA). Various cations Ca, P and Zn have been reported to play an important role both in the normal growth and remodelling of articular cartilage and subchondral bone as well as in the degenerative and inflammatory processes associated with the disease; they act as co-factors of a class of enzymes known as metalloproteinases which are believed to be active during the initiation, progress and remodelling processes associated with osteoarthritis. Other important enzymes such as alkaline phosphatase are associated with cartilage mineralization. Synchrotron radiation X-ray fluorescence (SR-XRF) for mapping of elemental distributions in bone and cartilage has also been employed by the present group and others. In the current investigations using the cSAXS beamline at the Swiss light source, Small-Angle X-ray Scattering (SAXS) was carried out on decalcified human articular cartilage to explore the structural and organizational changes of collagen networks in diseased articular cartilage.

Structural evaluation of an amyloid fibril model using small-angle x-ray scattering

Science.gov (United States)

Dahal, Eshan; Choi, Mina; Alam, Nadia; Bhirde, Ashwinkumar A.; Beaucage, Serge L.; Badano, Aldo

2017-08-01

Amyloid fibrils are highly structured protein aggregates associated with a wide range of diseases including Alzheimer’s and Parkinson’s. We report a structural investigation of an amyloid fibril model prepared from a commonly used plasma protein (bovine serum albumin (BSA)) using small-angle x-ray scattering (SAXS) technique. As a reference, the size estimates from SAXS are compared to dynamic light scattering (DLS) data and the presence of amyloid-like fibrils is confirmed using Congo red absorbance assay. Our SAXS results consistently show the structural transformation of BSA from spheroid to rod-like elongated structures during the fibril formation process. We observe the elongation of fibrils over two months with fibril length growing from 35.9  ±  3.0 nm to 51.5  ±  2.1 nm. Structurally metastable fibrils with distinct SAXS profiles have been identified. As proof of concept, we demonstrate the use of such distinct SAXS profiles to detect fibrils in the mixture solutions of two species by estimating their volume fractions. This easily detectable and well-characterized amyloid fibril model from BSA can be readily used as a control or standard reference to further investigate SAXS applications in the detection of structurally diverse amyloid fibrils associated with protein aggregation diseases.

Study of particles in solution by small angle x-ray scattering

International Nuclear Information System (INIS)

Itri, R.

1986-01-01

The implantation of SAXS technique is presented, and mycellas in solution of the dodecyl sodium sulfate SLS/water system are studied. A synthesis of SAXS theory to study parameters such as, volume, radii of gyration and specific surface and distribution function of the distance of homogenous and inhomogeneous particles is also presented. The technique was implanted by the study of a vitreous coal sample with voids in amorphous matrix. Computer programs were used for data treatment. It was concluded that the void configuration must be an oblate ellipsoid with rippled external surface and radii of gyration of ∼20A . The study of mycellas in solution of the SLL/H 2 O binary system showed spherical mycellas with paraffinic radii of 16A and total radii of 25.5 A. Interaction effects start to appear in 15% SLS concentrations. The change in the scattering curve occurs due to the interactions between mycellas. The isotropic-nematic transition in the ternary system by decanol addition was also investigated. (M.C.K.) [pt

Small-angle X-ray scattering documents the growth of metal-organic frameworks

NARCIS (Netherlands)

Goesten, M.G.; Stavitski, I.; Juan-Alcañiz, J.; Martinez-Joaristi, A.; Petukhov, A.V.; Kapteijn, F.; Gascon, J.

2013-01-01

We present a combined in situ small- and wide-angle scattering (SAXS/WAXS) study on the crystallization of two topical metal-organic frameworks synthesized from similar metal and organic precursors: NH2-MIL-53(Al) and NH2-MIL-101(Al). A thorough analysis of SAXS data reveals the most important

Probabilistic Equilibrium Sampling of Protein Structures from SAXS Data and a Coarse Grained Debye Formula

DEFF Research Database (Denmark)

Andreetta, Christian

-likelihood estimators for the form factors employed in the Debye formula, a theoretical forward model for SAXS profiles. The resulting computation compares favorably with the state of the art tool in the field, the program CRYSOL in the suite ATSAS. A faster, parallel implementation on Graphical Processor Units (GPUs......The present work describes the design and the implementation of a protocol for arbitrary precision computation of Small Angle X-ray Scattering (SAXS) profiles, and its inclusion in a probabilistic framework for protein structure determination. This protocol identifies a set of maximum...... of protein structures all fitting the experimental data. For the first time, we describe in full atomic detail a set of different conformations attainable by flexible polypeptides in solution. This method is not limited by assumptions in shape or size of the samples. It allows therefore to investigate...

Synchrotron SAXS/WAXD and rheological studies of clay suspensions in silicone fluid.

Science.gov (United States)

Zhang, Li-Ming; Jahns, Christopher; Hsiao, Benjamin S; Chu, Benjamin

2003-10-15

Suspensions of two commercial smectite clays, montmorillonite KSF and montmorillonite K10, in a low-viscosity silicone oil (Dow Corning 245 Fluid) were studied by simultaneous synchrotron small-angle X-ray scattering (SAXS)/wide-angle X-ray diffraction (WAXD) techniques and rheological measurements. In the 0.5% (w/v) KSF clay suspension and two K10 clay suspensions (0.5% and 1.0%), WAXD profiles below 2theta=10.0 degrees did not display any characteristic reflection peaks associated with the chosen montmorillonite clays, while corresponding SAXS profiles exhibited distinct scattering maxima, indicating that both clays were delaminated by the silicone oil. In spite of the large increase in viscosity, the clay suspensions exhibited no gel characteristics. Dynamic rheological experiments indicated that the clay/silicone oil suspensions exhibited the behavior of viscoelasticity, which could be influenced by the type and the concentration of the clay. For the K10 clay suspensions, the frequency-dependent loss modulus (G") was greater in magnitude than the storage modulus (G') in the concentration range from 0.5 to 12.0%. The increase in the clay concentration shifted the crossover point between G' and G" into the accessible frequency range, indicating that the system became more elastic. In contrast, the KSF clay suspension exhibited lower G' and G" values, indicating a weaker viscoelastic response. The larger viscoelasticity response in the K10 clay suspension may be due to the acid treatment generating a higher concentration of silanol groups on the clay surface.

New features at the LURE-D22 SAXS beamline

International Nuclear Information System (INIS)

Lesieur, P.; Lombardo, D.; Beauchet, L; Creof, C.; Decamps, T.; Dubuisson, J.M.; Perilhous, G.

1999-01-01

The D22 beamline of the DCI storage ring at LURE is dedicated to the study of structural properties in the field of material science by way of the small-angle X ray scattering (SAXS) technique. The D2 bending magnet of the DCI ring offers a stable source of limited brilliance but long decay time (200 hours) so that the beam can be used up to 110 hours after an injection of the positrons in the ring. Two different settings respectively dedicated to metallurgy and soft matter share the beam time. The latter which is considered here mainly deals with ill condensed matter: non ideal solutions of amphiphiles or polymers, liquid crystals, colloids, gels, xerogels, aerogels. (author)

An in situ USAXS-SAXS-WAXS study of precipitate size distribution evolution in a model Ni-based alloy.

Science.gov (United States)

Andrews, Ross N; Serio, Joseph; Muralidharan, Govindarajan; Ilavsky, Jan

2017-06-01

Intermetallic γ' precipitates typically strengthen nickel-based superalloys. The shape, size and spatial distribution of strengthening precipitates critically influence alloy strength, while their temporal evolution characteristics determine the high-temperature alloy stability. Combined ultra-small-, small- and wide-angle X-ray scattering (USAXS-SAXS-WAXS) analysis can be used to evaluate the temporal evolution of an alloy's precipitate size distribution (PSD) and phase structure during in situ heat treatment. Analysis of PSDs from USAXS-SAXS data employs either least-squares fitting of a preordained PSD model or a maximum entropy (MaxEnt) approach, the latter avoiding a priori definition of a functional form of the PSD. However, strong low- q scattering from grain boundaries and/or structure factor effects inhibit MaxEnt analysis of typical alloys. This work describes the extension of Bayesian-MaxEnt analysis methods to data exhibiting structure factor effects and low- q power law slopes and demonstrates their use in an in situ study of precipitate size evolution during heat treatment of a model Ni-Al-Si alloy.

A General Approach to Access Morphologies of Polyoxometalates in Solution by Using SAXS: An Ab Initio Modeling Protocol.

Science.gov (United States)

Li, Mu; Wang, Weiyu; Yin, Panchao

2018-05-02

Herein, we reported a general protocol for an ab initio modeling approach to deduce structure information of polyoxometalates (POMs) in solutions from scattering data collected by the small-angle X-ray scattering (SAXS) technique. To validate the protocol, the morphologies of a serious of known POMs in either aqueous or organic solvents were analyzed. The obtained particle morphologies were compared and confirmed with previous reported crystal structures. To extend the feasibility of the protocol to an unknown system of aqueous solutions of Na 2 MoO 4 with the pH ranging from -1 to 8.35, the formation of {Mo 36 } clusters was probed, identified, and confirmed by SAXS. The approach was further optimized with a multi-processing capability to achieve fast analysis of experimental data, thereby, facilitating in situ studies of formations of POMs in solutions. The advantage of this approach is to generate intuitive 3D models of POMs in solutions without confining information such as symmetries and possible sizes. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Solution structure of tRNA{sup Val} from refinement of homology model against residual dipolar coupling and SAXS data

Energy Technology Data Exchange (ETDEWEB)

Grishaev, Alexander, E-mail: AlexanderG@intra.niddk.nih.gov; Ying, Jinfa [National Institutes of Health, Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases (United States); Canny, Marella D.; Pardi, Arthur [University of Colorado, Boulder, Department of Chemistry and Biochemistry, 215 UCB (United States)], E-mail: Arthur.Pardi@Colorado.edu; Bax, Ad [National Institutes of Health, Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases (United States)], E-mail: bax@nih.gov

2008-10-15

A procedure is presented for refinement of a homology model of E. coli tRNA{sup Val}, originally based on the X-ray structure of yeast tRNA{sup Phe}, using experimental residual dipolar coupling (RDC) and small angle X-ray scattering (SAXS) data. A spherical sampling algorithm is described for refinement against SAXS data that does not require a globbic approximation, which is particularly important for nucleic acids where such approximations are less appropriate. Substantially higher speed of the algorithm also makes its application favorable for proteins. In addition to the SAXS data, the structure refinement employed a sparse set of NMR data consisting of 24 imino N-H{sup N} RDCs measured with Pf1 phage alignment, and 20 imino N-H{sup N} RDCs obtained from magnetic field dependent alignment of tRNA{sup Val}. The refinement strategy aims to largely retain the local geometry of the 58% identical tRNA{sup Phe} by ensuring that the atomic coordinates for short, overlapping segments of the ribose-phosphate backbone and the conserved base pairs remain close to those of the starting model. Local coordinate restraints are enforced using the non-crystallographic symmetry (NCS) term in the XPLOR-NIH or CNS software package, while still permitting modest movements of adjacent segments. The RDCs mainly drive the relative orientation of the helical arms, whereas the SAXS restraints ensure an overall molecular shape compatible with experimental scattering data. The resulting structure exhibits good cross-validation statistics (jack-knifed Q{sub free} = 14% for the Pf1 RDCs, compared to 25% for the starting model) and exhibits a larger angle between the two helical arms than observed in the X-ray structure of tRNA{sup Phe}, in agreement with previous NMR-based tRNA{sup Val} models.

Fractal morphology in lignite coal: a small angle x-ray scattering investigation

International Nuclear Information System (INIS)

Chitra, R.; Sen, D.; Mazumder, S.; Chandrasekaran, K.S.

1999-01-01

Small angle x-ray scattering technique has been used to study the pore morphology in lignite coal from Neyveli lignite mine (Tamilnadu, India). The sample were collected from three different locations of the same mine. SAXS profiles from all the three samples show almost identical functionality, irrespective of the locations from where the samples were collected. SAXS experiment using two different wavelengths also exhibit same functionality indicating the absence of multiple scattering. The analysis indicates the surface fractal nature of the pore morphology. The surface fractal dimension is calculated to be 2.58. (author)

Small-angle scattering study of mesoscopic structures in charged gel and their evolution on dehydration

DEFF Research Database (Denmark)

Sugiyama, Masaaki; Annaka, Masahiko; Hara, Kazuhiro

2003-01-01

Mesoscopic structures, with length scales similar to10(2) Angstrom, were investigated by small-angle X-ray and neutron scattering (SAXS and SANS) in several N-isopropylacrylamide-sodium acrylate (NIPA-SA) copolymeric hydrogels with varying [NIPA]/[SA] ratios and water contents. The SAXS experimen...

Collagen imaged by Coherent X-ray Diffraction: towards a complementary tool to conventional scanning SAXS

International Nuclear Information System (INIS)

Berenguer de la Cuesta, Felisa; Bean, Richard J; Bozec, Laurent; Robinson, Ian K; McCallion, Catriona; Wallace, Kris; Hiller, Jen C; Terrill, Nicholas J

2010-01-01

Third generation x-ray sources offer unique possibilities for exploiting coherence in the study of materials. New insights in the structure and dynamics of soft condensed matter and biological samples can be obtained by coherent x-ray diffraction (CXD). However, the experimental procedures for applying these methods to collagen tissues are still under development. We present here an investigation for the optimal procedure in order to obtain high quality CXD data from collagen tissues. Sample handling and preparation and adequate coherence defining apertures are among the more relevant factors to take into account. The impact of the results is also discussed, in particular in comparison with the information that can be extracted from conventional scanning small angle x-ray scattering (SAXS). Images of collagen tissues obtained by CXD reconstructions will give additional information about the local structure with higher resolution and will complement scanning SAXS images.

Collagen imaged by Coherent X-ray Diffraction: towards a complementary tool to conventional scanning SAXS

Energy Technology Data Exchange (ETDEWEB)

Berenguer de la Cuesta, Felisa; Bean, Richard J; Bozec, Laurent; Robinson, Ian K [London Centre for Nanotechnology (LCN), University College London (UCL), London WC1H 0AH (United Kingdom); McCallion, Catriona; Wallace, Kris [Department of Physics and Astronomy, University College London (UCL), London WC1E 6BT (United Kingdom); Hiller, Jen C; Terrill, Nicholas J, E-mail: f.berenguer@ucl.ac.u [Diamond Light Source, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0DE (United Kingdom)

2010-10-01

Third generation x-ray sources offer unique possibilities for exploiting coherence in the study of materials. New insights in the structure and dynamics of soft condensed matter and biological samples can be obtained by coherent x-ray diffraction (CXD). However, the experimental procedures for applying these methods to collagen tissues are still under development. We present here an investigation for the optimal procedure in order to obtain high quality CXD data from collagen tissues. Sample handling and preparation and adequate coherence defining apertures are among the more relevant factors to take into account. The impact of the results is also discussed, in particular in comparison with the information that can be extracted from conventional scanning small angle x-ray scattering (SAXS). Images of collagen tissues obtained by CXD reconstructions will give additional information about the local structure with higher resolution and will complement scanning SAXS images.

The accurate assessment of small-angle X-ray scattering data.

Science.gov (United States)

Grant, Thomas D; Luft, Joseph R; Carter, Lester G; Matsui, Tsutomu; Weiss, Thomas M; Martel, Anne; Snell, Edward H

2015-01-01

Small-angle X-ray scattering (SAXS) has grown in popularity in recent times with the advent of bright synchrotron X-ray sources, powerful computational resources and algorithms enabling the calculation of increasingly complex models. However, the lack of standardized data-quality metrics presents difficulties for the growing user community in accurately assessing the quality of experimental SAXS data. Here, a series of metrics to quantitatively describe SAXS data in an objective manner using statistical evaluations are defined. These metrics are applied to identify the effects of radiation damage, concentration dependence and interparticle interactions on SAXS data from a set of 27 previously described targets for which high-resolution structures have been determined via X-ray crystallography or nuclear magnetic resonance (NMR) spectroscopy. The studies show that these metrics are sufficient to characterize SAXS data quality on a small sample set with statistical rigor and sensitivity similar to or better than manual analysis. The development of data-quality analysis strategies such as these initial efforts is needed to enable the accurate and unbiased assessment of SAXS data quality.

SANS and SAXS study of block copolymer/homopolymer mixtures

International Nuclear Information System (INIS)

Hasegawa, Hirokazu; Tanaka, Hideaki; Hashimoto, Takeji; Han, C.C.

1991-01-01

The lateral and vertical components of the radius of gyration for a single block copolymer chain and those of a single homopolymer chain in the lamellar microdomain space formed by a mixture of diblock copolymers and homopolymers were investigated by means of small-angle neutron scattering (SANS) and the microdomain structures by small-angle X-ray scattering (SAXS). The homopolymers whose molecular weights are much smaller than that of the corresponding chains of the block copolymers were used so that the homopolymers were uniformly solubilized in the corresponding microdomains. The SANS result suggests that the homopolymer chains in the microdomain space as well as the block copolymer chains are more compressed in the direction parallel to the interface and more stretched in the direction perpendicular to the interface than the corresponding unperturbed polymer chains with the same molecular weight. On increasing the volume fraction of the homopolymers the thickness of the lamellar microdomains increases. The block copolymer chains were found to undergo an isochoric affine deformation on addition of the homopolymers or with the change of the thickness of the lamellar microdomains. (orig.)

Effects of high pressure on internally self-assembled lipid nanoparticles: a synchrotron small-angle X-ray scattering (SAXS) study

Czech Academy of Sciences Publication Activity Database

Kulkarni, C. V.; Yaghmur, A.; Steinhart, Miloš; Kriechbaum, M.; Rappolt, M.

2016-01-01

Roč. 32, č. 45 (2016), s. 11907-11917 ISSN 0743-7463 Institutional support: RVO:61389013 Keywords : self-assebled lipid nanoparticles * synchrotron * SAXS Subject RIV: CD - Macromolecular Chemistry Impact factor: 3.833, year: 2016

Determination of the quaternary structural states of bovine casein by small-angle X-ray scattering: submicellar and micellar forms

International Nuclear Information System (INIS)

Kumosinski, T.F.; Pessen, H.; Farrell, H.M. Jr.; Brumberger, H.

1988-01-01

Whole casein occurs in milk as a spherical colloidal complex of protein and salts called the casein micelle, with approximate average radii of 650 A as determined by electron microscopy. Removal of Ca2+ is thought to result in dissociation into smaller noncolloidal protein complexes called submicelles. Hydrodynamic and light scattering studies on whole casein submicelles suggest that they are predominantly spherical particles with a hydrophobic core. To investigate whether the integrity of a hydrophobically stabilized submicellar structure is preserved in the electrostatically stabilized colloidal micellar structure, small-angle X-ray scattering (SAXS) experiments were undertaken on whole casein from bovine milk under submicellar and micellar conditions. All SAXS results showed multiple Gaussian character and could be analyzed best by nonlinear regression in place of the customary Guinier plot. Analysis of the SAXS data for submicellar casein showed two Gaussian components which could be interpreted in terms of a particle with two concentric regions of different electron density, designated as a compact core and a loose shell, respectively. The submicelle was found to have an average molecular weight of 285,000 +/- 14,600 and a mass fraction of higher electron density core, k, of 0.212 +/- 0.028. The radius of gyration of the core, RC, was 37.98 +/- 0.01 A with an electron density difference, delta rho C, of 0.0148 +/- 0.0014 e-/A3, while the loose region had values of RL = 88.2 +/- 0.8 A with delta rho L = 0.0091 +/- 0.0003 e-/A3. Calculated distance distribution functions and normalized scattering curves also were consistent with an overall spherical particle with a concentric spherical inner core of higher electron density. (Abstract Truncated)

Investigation of the structure of human dental tissue at multiple length scales using high energy synchrotron X-ray SAXS/WAXS

Science.gov (United States)

Sui, Tan; Landini, Gabriel; Korsunsky, Alexander M.

2011-10-01

High energy (>50keV) synchrotron X-ray scattering experiments were carried out on beamline I12 JEEP at the Diamond Light Source (DLS, Oxford, UK). Although a complete human tooth could be studied, in the present study attention was focused on coupons from the region of the Dentin-Enamel Junction (DEJ). Simultaneous high energy SAXS/WAXS measurements were carried out. Quantitative analysis of the results allows multiple length scale characterization of the nano-crystalline structure of dental tissues. SAXS patterns analysis provide insight into the mean thickness and orientation of hydroxyapatite particles, while WAXS (XRD) patterns allow the determination of the crystallographic unit cell parameters of the hydroxyapatite phase. It was found that the average particle thickness determined from SAXS interpretation varies as a function of position in the vicinity of the DEJ. Most mineral particles are randomly orientated within dentin, although preferred orientation emerges and becomes stronger on approach to the enamel. Within the enamel, texture is stronger than anywhere in the dentin, and the determination of lattice parameters can be accomplished by Pawley refinement of the multiple peak diffraction pattern. The results demonstrate the feasibility of using high energy synchrotron X-ray beams for the characterization of human dental tissues. This opens up the opportunity of studying thick samples (e.g., complete teeth) in complex sample environments (e.g., under saline solution). This opens new avenues for the application of high energy synchrotron X-ray scattering to dental research.

Scanning small angle X-ray scattering investigations of bone

International Nuclear Information System (INIS)

Rinnerthaler, S.

1998-06-01

An important characteristic of bone is its strength, which is determined by bone mass, architecture and material quality. From a physical point of view bone is a composite material consisting of an organic matrix (collagen) and of inlets of mineral crystals (hydroxyapatite). These components build up a hierarchical, heterogeneous structure. The size of the mineral crystals lies in the nano-meter range and can be investigated by positionsensitive Small-Angle X-ray Scattering (Scanning-SAXS) in a non-destructive way. The average thickness, the degree and direction of the predominant orientation, as well as some information about shape and arrangement of the mineral crystals were determined in bones of humans, mice, and baboons by Scanning-SAXS with respect to age, bone diseases (osteogenesis imperfecta, pycnodysostosis) or medical treatments (fluoride or alendronate) of osteoporosis. The crystal thickness and the degree of orientation is much smaller in young individuals than in adults and the predominant orientation of the mineral crystals is different in a mixture of bone and mineralized cartilage compared to bone. Further, because position-resolved measurements are now possible, results from Scanning-SAXS measurements could be compared with the results of other position resolved methods. Due to this new feature it was possible, for the first time, to correlate directly 'mottled' bone visible in back-scattered electron imaging with small η-parameters evaluated from SAXS-patterns and the course of the collagen fibers with the predominant orientation of the mineral crystals. Scanning-SAXS proved to be a powerful tool to characterize bone nano-structure. (author)

Comparative SAXS and DSC study on stratum corneum structural organization in an epidermal cell culture model (ROC)

DEFF Research Database (Denmark)

Kuntsche, Judith; Herre, Angela; Fahr, Alfred

2013-01-01

barrier similar to that of human stratum corneum is, however, a prerequisite. In this study, the stratum corneum lipid organization in an epidermal cell culture model based on rat epidermal keratinocytes (REK organotypic culture, ROC) was investigated by small-angle X-ray scattering (SAXS) in dependence......Cell cultured skin equivalents present an alternative for dermatological in vitro evaluations of drugs and excipients as they provide the advantage of availability, lower variability and higher assay robustness compared to native skin. For penetration/permeation studies, an adequate stratum corneum...... and SC lipid organization. Cultivation for 21days resulted in further minor changes in the structural organization of ROC SC. The SAXS patterns of ROC SC had overall large similarities with that of human SC and point to the presence of a long periodicity phase with a repeat distance of about 122Å, e...

SAXS and other spectroscopic analysis of 12S cruciferin isolated from the seeds of Brassica nigra

Science.gov (United States)

Khaliq, Binish; Falke, Sven; Negm, Amr; Buck, Friedrich; Munawar, Aisha; Saqib, Maria; Mahmood, Seema; Ahmad, Malik Shoaib; Betzel, Christian; Akrem, Ahmed

2017-06-01

Oilseeds of the plant family Brassicaceae are important for providing both lipid and protein contents to human nutrition. Cruciferins (12S globulins) are seed storage proteins, which are getting attention due to their allergenic and pathogenicity related nature. This study describes the purification and characterization of a trimeric (∼190 kDa) cruciferin protein from the seeds of Brassica nigra (L.). Cruciferin was first partially purified by ammonium sulfate precipitation (30% saturation constant) and further purified by size exclusion chromatography. The N-terminal amino-acid sequence analysis showed 82% sequence homology with cruciferin from Arabidopsis thaliana. The 50-55 kDa monomeric cruciferin produced multiple bands of two major molecular weight ranges (α-polypeptides of 28-32 kDa and β-polypeptides of 17-20 kDa) under reduced conditions of SDS-PAGE. The 2D gel electrophoretic analysis showed the further separation of the bands into their isoforms with major pI ranges between 5.7 and 8.0 (α-polypeptides) and 5.5-8.5 (β-polypeptides). The Dynamic Light Scattering (DLS) showed the monodisperse nature of the cruciferin with hydrodynamic radius of 5.8 ± 0.1 nm confirming the trimeric nature of the protein. The Circular Dichroism (CD) spectra showed both α-helices and β-sheets in the native conformation of the trimeric protein. The pure cruciferin protein (40 mg/ml) was successfully crystallized; however, the crystals diffracted only to low resolution data (8 Å). Small-angle x-ray scattering (SAXS) was applied to gain insights into the three-dimensional structure in solution. SAXS showed that the radius of gyration is 4.24 ± 0.25 nm and confirmed the nearly globular shape. The SAXS based ab initio dummy model of B. nigra cruciferin was compared with 11S globulins.

In situ microfluidic dialysis for biological small-angle X-ray scattering

DEFF Research Database (Denmark)

Skou, Magda; Skou, Soren; Jensen, Thomas Glasdam

2014-01-01

Owing to the demand for low sample consumption and automated sample changing capabilities at synchrotron small-angle X-ray (solution) scattering (SAXS) beamlines, X-ray microfluidics is receiving continuously increasing attention. Here, a remote-controlled microfluidic device is presented for sim...... in incidental sample purification. Hence, this versatile microfluidic device enables investigation of experimentally induced structural changes under dynamically controllable sample conditions. (C) 2014 International Union of Crystallography......Owing to the demand for low sample consumption and automated sample changing capabilities at synchrotron small-angle X-ray (solution) scattering (SAXS) beamlines, X-ray microfluidics is receiving continuously increasing attention. Here, a remote-controlled microfluidic device is presented...

Anomalous small-angle scattering as a way to solve the Babinet principle problem

International Nuclear Information System (INIS)

Boiko, M. E.; Sharkov, M. D.; Boiko, A. M.; Bobyl, A. V.

2013-01-01

X-ray absorption spectra (XAS) have been used to determine the absorption edges of atoms present in a sample under study. A series of small-angle X-ray scattering (SAXS) measurements using different monochromatic X-ray beams at different wavelengths near the absorption edges is performed to solve the Babinet principle problem. The sizes of clusters containing atoms determined by the method of XAS were defined in SAXS experiments. In contrast to differential X-ray porosimetry, anomalous SAXS makes it possible to determine sizes of clusters of different atomic compositions

Anomalous small-angle scattering as a way to solve the Babinet principle problem

Energy Technology Data Exchange (ETDEWEB)

Boiko, M. E., E-mail: m.e.boiko@mail.ioffe.ru; Sharkov, M. D.; Boiko, A. M.; Bobyl, A. V. [Russian Academy of Sciences, Ioffe Physicotechnical Institute (Russian Federation)

2013-12-15

X-ray absorption spectra (XAS) have been used to determine the absorption edges of atoms present in a sample under study. A series of small-angle X-ray scattering (SAXS) measurements using different monochromatic X-ray beams at different wavelengths near the absorption edges is performed to solve the Babinet principle problem. The sizes of clusters containing atoms determined by the method of XAS were defined in SAXS experiments. In contrast to differential X-ray porosimetry, anomalous SAXS makes it possible to determine sizes of clusters of different atomic compositions.

Anomalous small-angle scattering as a way to solve the Babinet principle problem

Science.gov (United States)

Boiko, M. E.; Sharkov, M. D.; Boiko, A. M.; Bobyl, A. V.

2013-12-01

X-ray absorption spectra (XAS) have been used to determine the absorption edges of atoms present in a sample under study. A series of small-angle X-ray scattering (SAXS) measurements using different monochromatic X-ray beams at different wavelengths near the absorption edges is performed to solve the Babinet principle problem. The sizes of clusters containing atoms determined by the method of XAS were defined in SAXS experiments. In contrast to differential X-ray porosimetry, anomalous SAXS makes it possible to determine sizes of clusters of different atomic compositions.

Rheo-SAXS investigation of shear-thinning behaviour of very anisometric repulsive disc-like clay suspensions.

Science.gov (United States)

Philippe, A M; Baravian, C; Imperor-Clerc, M; De Silva, J; Paineau, E; Bihannic, I; Davidson, P; Meneau, F; Levitz, P; Michot, L J

2011-05-18

Aqueous suspensions of swelling clay minerals exhibit a rich and complex rheological behaviour. In particular, these repulsive systems display strong shear-thinning at very low volume fractions in both the isotropic and gel states. In this paper, we investigate the evolution with shear of the orientational distribution of aqueous clay suspensions by synchrotron-based rheo-SAXS experiments using a Couette device. Measurements in radial and tangential configurations were carried out for two swelling clay minerals of similar morphology and size, Wyoming montmorillonite and Idaho beidellite. The shear evolution of the small angle x-ray scattering (SAXS) patterns displays significantly different features for these two minerals. The detailed analysis of the angular dependence of the SAXS patterns in both directions provides the average Euler angles of the statistical effective particle in the shear plane. We show that for both samples, the average orientation is fully controlled by the local shear stress around the particle. We then apply an effective approach to take into account multiple hydrodynamic interactions in the system. Using such an approach, it is possible to calculate the evolution of viscosity as a function of shear rate from the knowledge of the average orientation of the particles. The viscosity thus recalculated almost perfectly matches the measured values as long as collective effects are not too important in the system.

Rheo-SAXS investigation of shear-thinning behaviour of very anisometric repulsive disc-like clay suspensions

International Nuclear Information System (INIS)

Philippe, A M; Baravian, C; Imperor-Clerc, M; De Silva, J; Davidson, P; Paineau, E; Bihannic, I; Michot, L J; Meneau, F; Levitz, P

2011-01-01

Aqueous suspensions of swelling clay minerals exhibit a rich and complex rheological behaviour. In particular, these repulsive systems display strong shear-thinning at very low volume fractions in both the isotropic and gel states. In this paper, we investigate the evolution with shear of the orientational distribution of aqueous clay suspensions by synchrotron-based rheo-SAXS experiments using a Couette device. Measurements in radial and tangential configurations were carried out for two swelling clay minerals of similar morphology and size, Wyoming montmorillonite and Idaho beidellite. The shear evolution of the small angle x-ray scattering (SAXS) patterns displays significantly different features for these two minerals. The detailed analysis of the angular dependence of the SAXS patterns in both directions provides the average Euler angles of the statistical effective particle in the shear plane. We show that for both samples, the average orientation is fully controlled by the local shear stress around the particle. We then apply an effective approach to take into account multiple hydrodynamic interactions in the system. Using such an approach, it is possible to calculate the evolution of viscosity as a function of shear rate from the knowledge of the average orientation of the particles. The viscosity thus recalculated almost perfectly matches the measured values as long as collective effects are not too important in the system.

Study of a new approach to diagnose breast cancer based on synchrotron radiation scattering properties

International Nuclear Information System (INIS)

Conceicao, A.L.C.; Poletti, M.E.

2012-01-01

Full text: Breast cancer is the most frequently occurring cancer in women accounting for about 20% of all cancer deaths. This scenario is, among other factors, due to inherent limitations of the current clinical methods of diagnosis based on x-ray absorption. Meanwhile, recent researches have shown that the scattered radiation can provide information about the structures that compose a biological tissue, like breast tissue. Then, the information provided by x-ray scattering techniques can be used to identify breast cancer. In this work, we developed a classification model based on discriminant analysis of scattering profiles of 106 human breast samples histopathologically classified as normal tissue, benign and malignant lesion, at wide (WAXS) and small angle x-ray scattering (SAXS) regions. WAXS and SAXS experiments were carried out at the D12A-XRD1 and D02-SAXS2 beam lines in the National Synchrotron Light Laboratory (LNLS) in Campinas. For WAXS experiment, was used an x-ray beam energy of 11keV allowing to record the momentum transfer interval of 0.7nm -1 ≤(q=4π.sin(θ/2)/λ)≤70.5nm -1 on the NaI(Tl) detector. While for SAXS experiment was used an x-ray wavelength of 1.488 Angstrom, a two-dimensional detector and several sample-detector distances, allowing to get the range of 0.07nm -1 ≤q≤4.20nm -1 . The scattering profiles at both regions, for each sample were used to build the diagnosis model based on discriminant analysis. From WAXS data, differences related to position and intensity of the peaks of the molecular structures were found, when compared normal and pathological breast tissues. While for SAXS these differences were observed in supramolecular structures. The diagnostic model combining the information at WAXS and SAXS yield two linear functions which, allow to correlate changes at molecular scale with those at supramolecular level as well as, to classify correctly all samples analyzed in this study[1]. Finally, the results achieved in this

The current status of small-angle x-ray scattering beamline at Diamond Light Source

International Nuclear Information System (INIS)

Inoue, Katsuaki; Doutch, James; Terrill, Nick

2013-01-01

The small-angle X-ray scattering (SAXS) covers the major disciplines of biology, chemistry and physics delivering structural and dynamic information in nanoscience, mesoscopic architectures, supramolecular structures, and nucleation/growth of crystals. SAXS is also proving to be important in archaeological, environmental, and conservation sciences, and has further indicated its ability to span wide-ranging scientific disciplines. Thus, strong needs for SAXS studies are increasing significantly in a broad range of scientific fields year by year. Based on such a background, the demand for high throughput SAXS experiments is increasing. At the synchrotron facility, Diamond Light Source, one SAXS beamline, Non-crystalline diffraction I22 is now operational and highly automated throughput small-angle X-ray scattering (HATSAXS) beamline B21 is now under construction. I22 is the Undulator beamline and wide varieties of experiments, including time-resolved experiments are attempted. Based on the concept of HATSAXS, the key feature of B21 will focuses on the automation of end-station equipment. A automated sample changer has been purchased for solution SAXS measurements on biomolecules. A robotic-arm-type automated sample changer that is capable of handling several kinds of samples in material science is also being constructed. B21 is expected to successfully provide all users highly automated throughput measurements with the highest possible reliability and accuracy. Construction of this beamline will end in the second half of 2012, and will be open for users in the early summer of 2013 after commissioning. (author)

Preliminary Examination of X-ray Scattering from Human Tissues

International Nuclear Information System (INIS)

Desouky, O.S.; Wilkinson, S.; Hall, C.; Rogers, K.; Round, A.

2008-01-01

Small Angle x-ray scattering (SAXS) and wide angle x-ray scattering (WAXS) patterns have been recorded from different human soft tissues using x-ray synchrotron radiation.Pathological breast, normal kidney and lung tissues show SAXS peaks at q-values equal to 0.291 nm -1 and 0.481 nm -1 (d 21.6 nm and d =13. nm) which are the 3 r d and 5 t h order of the well known axial D-spacing of collagen fibrils. The diffraction is particularly intense in the meridional direction indicating some febrile alignment. In contrast, the normal tissue of brain, liver and heart shows diffuse scatter.The wide-angle coherent scattering from normal human tissues of brain, liver, heart, lung, and kidney is typical of that for amorphous materials. The scatter of the healthy adipose breast tissue shows a sharp peak at momentum transfer 1.24 nm -1 (d= 0.417 nm). The data of the other tissues appears to consist of a broad scattering peak. The two scattering regimes succeed in differentiating between the two major components of breast tissue, collagen and adipose tissue. The results of this study suggest that the soft tissues may have scattering patterns that are characteristics for the particular tissue types and tissue disease state. These results indicate that it may be possible use the coherent scattering as a diagnostic tool

X-ray coherent scattering tomography of textured material (Conference Presentation)

Science.gov (United States)

Zhu, Zheyuan; Pang, Shuo

2017-05-01

Small-angle X-ray scattering (SAXS) measures the signature of angular-dependent coherently scattered X-rays, which contains richer information in material composition and structure compared to conventional absorption-based computed tomography. SAXS image reconstruction method of a 2 or 3 dimensional object based on computed tomography, termed as coherent scattering computed tomography (CSCT), enables the detection of spatially-resolved, material-specific isotropic scattering signature inside an extended object, and provides improved contrast for medical diagnosis, security screening, and material characterization applications. However, traditional CSCT methods assumes materials are fine powders or amorphous, and possess isotropic scattering profiles, which is not generally true for all materials. Anisotropic scatters cannot be captured using conventional CSCT method and result in reconstruction errors. To obtain correct information from the sample, we designed new imaging strategy which incorporates extra degree of detector motion into X-ray scattering tomography for the detection of anisotropic scattered photons from a series of two-dimensional intensity measurements. Using a table-top, narrow-band X-ray source and a panel detector, we demonstrate the anisotropic scattering profile captured from an extended object and the reconstruction of a three-dimensional object. For materials possessing a well-organized crystalline structure with certain symmetry, the scatter texture is more predictable. We will also discuss the compressive schemes and implementation of data acquisition to improve the collection efficiency and accelerate the imaging process.

Characterization of Nanocellulose Using Small-Angle Neutron, X-ray, and Dynamic Light Scattering Techniques.

Science.gov (United States)

Mao, Yimin; Liu, Kai; Zhan, Chengbo; Geng, Lihong; Chu, Benjamin; Hsiao, Benjamin S

2017-02-16

Nanocellulose extracted from wood pulps using TEMPO (2,2,6,6-tetramethylpiperidine-1-oxyl radical)-mediated oxidation and sulfuric acid hydrolysis methods was characterized by small-angle neutron scattering (SANS), small-angle X-ray scattering (SAXS), and dynamic light scattering (DLS) techniques. The dimensions of this nanocellulose (TEMPO-oxidized cellulose nanofiber (TOCN) and sulfuric acid hydrolyzed cellulose nanocrystal (SACN)) revealed by the different scattering methods were compared with those characterized by transmission electron microscopy (TEM). The SANS and SAXS data were analyzed using a parallelepiped-based form factor. The width and thickness of the nanocellulose cross section were ∼8 and ∼2 nm for TOCN and ∼20 and ∼3 nm for SACN, respectively, where the fitting results from SANS and SAXS profiles were consistent with each other. DLS was carried out under both the V V mode with the polarizer and analyzer parallel to each other and the H V mode having them perpendicular to each other. Using rotational and translational diffusion coefficients obtained under the H V mode yielded a nanocellulose length qualitatively consistent with that observed by TEM, whereas the length derived by the translational diffusion coefficient under the V V mode appeared to be overestimated.

Mineral crystal alignment in mineralized fracture callus determined by 3D small-angle X-ray scattering

Energy Technology Data Exchange (ETDEWEB)

Liu Yifei; Manjubala, Inderchand; Fratzl, Peter [Department of Biomaterials, Max Planck Institute of Colloids and Interfaces, 14424 Potsdam (Germany); Roschger, Paul [4th Medical Department, Ludwig Boltzmann Institute of Osteology at Hanusch Hospital of WGKK and AUVA Trauma Centre Meidling, 1140 Vienna (Austria); Schell, Hanna; Duda, Georg N, E-mail: fratzl@mpikg.mpg.d [Julius Wolff Institut and Center for Musculoskeletal Surgery, Charite- University Medicine Berlin, Augustenburger Platz 1, 13353 Berlin (Germany)

2010-10-01

Callus tissue formed during bone fracture healing is a mixture of different tissue types as revealed by histological analysis. But the structural characteristics of mineral crystals within the healing callus are not well known. Since two-dimensional (2D) scanning small-angle X-ray scattering (sSAXS) patterns showed that the size and orientation of callus crystals vary both spatially and temporally [1] and 2D electron microscopic analysis implies an anisotropic property of the callus morphology, the mineral crystals within the callus are also expected to vary in size and orientation in 3D. Three-dimensional small-angle X-ray scattering (3D SAXS), which combines 2D SAXS patterns collected at different angles of sample tilting, has been previously applied to investigate bone minerals in horse radius [2] and oim/oim mouse femur/tibia [3]. We implement a similar 3D SAXS method but with a different way of data analysis to gather information on the mineral alignment in fracture callus. With the proposed accurate yet fast assessment of 3D SAXS information, it was shown that the plate shaped mineral particles in the healing callus were aligned in groups with their predominant orientations occurring as a fiber texture.

Mineral crystal alignment in mineralized fracture callus determined by 3D small-angle X-ray scattering

International Nuclear Information System (INIS)

Liu Yifei; Manjubala, Inderchand; Fratzl, Peter; Roschger, Paul; Schell, Hanna; Duda, Georg N

2010-01-01

Callus tissue formed during bone fracture healing is a mixture of different tissue types as revealed by histological analysis. But the structural characteristics of mineral crystals within the healing callus are not well known. Since two-dimensional (2D) scanning small-angle X-ray scattering (sSAXS) patterns showed that the size and orientation of callus crystals vary both spatially and temporally [1] and 2D electron microscopic analysis implies an anisotropic property of the callus morphology, the mineral crystals within the callus are also expected to vary in size and orientation in 3D. Three-dimensional small-angle X-ray scattering (3D SAXS), which combines 2D SAXS patterns collected at different angles of sample tilting, has been previously applied to investigate bone minerals in horse radius [2] and oim/oim mouse femur/tibia [3]. We implement a similar 3D SAXS method but with a different way of data analysis to gather information on the mineral alignment in fracture callus. With the proposed accurate yet fast assessment of 3D SAXS information, it was shown that the plate shaped mineral particles in the healing callus were aligned in groups with their predominant orientations occurring as a fiber texture.

Mapping of unfolding states of integral helical membrane proteins by GPS-NMR and scattering techniques

DEFF Research Database (Denmark)

Calcutta, Antonello; Jessen, Christian M; Behrens, Manja Annette

2012-01-01

induced by unfolding of an integral membrane protein, namely TFE-induced unfolding of KcsA solubilized by the n-dodecyl ß-d-maltoside (DDM) surfactant is investigated by the recently introduced GPS-NMR (Global Protein folding State mapping by multivariate NMR) (Malmendal et al., PlosONE 5, e10262 (2010......)) along with dynamic light scattering (DLS) and small-angle X-ray scattering (SAXS). GPS-NMR is used as a tool for fast analysis of the protein unfolding processes upon external perturbation, and DLS and SAXS are used for further structural characterization of the unfolding states. The combination allows...

SAXS and stability studies of iron-induced oligomers of bacterial frataxin CyaY.

Directory of Open Access Journals (Sweden)

Mostafa Fekry

Full Text Available Frataxin is a highly conserved protein found in both prokaryotes and eukaryotes. It is involved in several central functions in cells, which include iron delivery to biochemical processes, such as heme synthesis, assembly of iron-sulfur clusters (ISC, storage of surplus iron in conditions of iron overload, and repair of ISC in aconitase. Frataxin from different organisms has been shown to undergo iron-dependent oligomerization. At least two different classes of oligomers, with different modes of oligomer packing and stabilization, have been identified. Here, we continue our efforts to explore the factors that control the oligomerization of frataxin from different organisms, and focus on E. coli frataxin CyaY. Using small-angle X-ray scattering (SAXS, we show that higher iron-to-protein ratios lead to larger oligomeric species, and that oligomerization proceeds in a linear fashion as a results of iron oxidation. Native mass spectrometry and online size-exclusion chromatography combined with SAXS show that a dimer is the most common form of CyaY in the presence of iron at atmospheric conditions. Modeling of the dimer using the SAXS data confirms the earlier proposed head-to-tail packing arrangement of monomers. This packing mode brings several conserved acidic residues into close proximity to each other, creating an environment for metal ion binding and possibly even mineralization. Together with negative-stain electron microscopy, the experiments also show that trimers, tetramers, pentamers, and presumably higher-order oligomers may exist in solution. Nano-differential scanning fluorimetry shows that the oligomers have limited stability and may easily dissociate at elevated temperatures. The factors affecting the possible oligomerization mode are discussed.

A preliminary study of breast cancer diagnosis using laboratory based small angle x-ray scattering

Science.gov (United States)

Round, A. R.; Wilkinson, S. J.; Hall, C. J.; Rogers, K. D.; Glatter, O.; Wess, T.; Ellis, I. O.

2005-09-01

Breast tissue collected from tumour samples and normal tissue from bi-lateral mastectomy procedures were examined using small angle x-ray scattering. Previous work has indicated that breast tissue disease diagnosis could be performed using small angle x-ray scattering (SAXS) from a synchrotron radiation source. The technique would be more useful to health services if it could be made to work using a conventional x-ray source. Consistent and reliable differences in x-ray scatter distributions were observed between samples from normal and tumour tissue samples using the laboratory based 'SAXSess' system. Albeit from a small number of samples, a sensitivity of 100% was obtained. This result encourages us to pursue the implementation of SAXS as a laboratory based diagnosis technique.

A preliminary study of breast cancer diagnosis using laboratory based small angle x-ray scattering

Energy Technology Data Exchange (ETDEWEB)

Round, A R [Daresbury Laboratories, Warrington, WA4 4AD (United Kingdom); Wilkinson, S J [Daresbury Laboratories, Warrington, WA4 4AD (United Kingdom); Hall, C J [Daresbury Laboratories, Warrington, WA4 4AD (United Kingdom); Rogers, K D [Department of Materials and Medical Sciences, Cranfield University, Swindon, SN6 8LA (United Kingdom); Glatter, O [Department of Chemistry, University of Graz (Austria); Wess, T [School of Optometry and Vision Sciences, Cardiff University, Cardiff CF10 3NB, Wales (United Kingdom); Ellis, I O [Nottingham City Hospital, Nottingham (United Kingdom)

2005-09-07

Breast tissue collected from tumour samples and normal tissue from bi-lateral mastectomy procedures were examined using small angle x-ray scattering. Previous work has indicated that breast tissue disease diagnosis could be performed using small angle x-ray scattering (SAXS) from a synchrotron radiation source. The technique would be more useful to health services if it could be made to work using a conventional x-ray source. Consistent and reliable differences in x-ray scatter distributions were observed between samples from normal and tumour tissue samples using the laboratory based 'SAXSess' system. Albeit from a small number of samples, a sensitivity of 100% was obtained. This result encourages us to pursue the implementation of SAXS as a laboratory based diagnosis technique.

A preliminary study of breast cancer diagnosis using laboratory based small angle x-ray scattering

International Nuclear Information System (INIS)

Round, A R; Wilkinson, S J; Hall, C J; Rogers, K D; Glatter, O; Wess, T; Ellis, I O

2005-01-01

Breast tissue collected from tumour samples and normal tissue from bi-lateral mastectomy procedures were examined using small angle x-ray scattering. Previous work has indicated that breast tissue disease diagnosis could be performed using small angle x-ray scattering (SAXS) from a synchrotron radiation source. The technique would be more useful to health services if it could be made to work using a conventional x-ray source. Consistent and reliable differences in x-ray scatter distributions were observed between samples from normal and tumour tissue samples using the laboratory based 'SAXSess' system. Albeit from a small number of samples, a sensitivity of 100% was obtained. This result encourages us to pursue the implementation of SAXS as a laboratory based diagnosis technique

Quantification of RNA in bacteriophage MS2-like viruses in solution by small-angle X-ray scattering

International Nuclear Information System (INIS)

Kuzmanovic, Deborah A.; Elashvili, Ilya; Wick, Charles; O'Connell, Catherine; Krueger, Susan

2006-01-01

Recombinant forms of bacteriophage MS2 virus particles, wild-type MS2 and MS2 capsids have been examined in solution using small-angle X-ray scattering (SAXS). SAXS was used to determine the overall size of the virus particles and to quantify the amount of encapsulated viral RNA. These studies show that analysis of natural and recombinant forms of MS2 virus by SAXS can be used as both a quantitative measure of nucleic acid content in situ and diagnostic indicator of sample integrity

Studies of protein structure in solution and protein folding using synchrotron small-angle x-ray scattering

Energy Technology Data Exchange (ETDEWEB)

Chen, Lingling [Stanford Univ., CA (United States)

1996-04-01

Synchrotron small angle x-ray scattering (SAXS) has been applied to the structural study of several biological systems, including the nitrogenase complex, the heat shock cognate protein (hsc70), and lysozyme folding. The structural information revealed from the SAXS experiments is complementary to information obtained by other physical and biochemical methods, and adds to our knowledge and understanding of these systems.

A new small-angle X-ray scattering set-up on the crystallography beamline I711 at MAX-lab

DEFF Research Database (Denmark)

Knaapila, M.; Svensson, C.; Barauskas, J.

2009-01-01

A small-angle X-ray scattering (SAXS) set-up has recently been developed at beamline I711 at the MAX II storage ring in Lund (Sweden). An overview of the required modifications is presented here together with a number of application examples. The accessible q range in a SAXS experiment is 0.009-0...

Six Years of Gamma Ray Burst Observations with BeppoSAX

OpenAIRE

Frontera, Filippo

2004-01-01

I give a summary of the prompt X-/gamma-ray detections of Gamma Ray Bursts (GRBs) with the BeppoSAX satellite and discuss some significant results obtained from the study of the prompt emission of these GRBs obtained with the BeppoSAX Gamma Ray Burst Monitor and Wide Field Cameras.

Small-angle X-ray scattering of solutions

International Nuclear Information System (INIS)

Koch, M.H.J.; Stuhrmann, H.B.; Vachette, P.; Tardieu, A.

1982-01-01

The use of synchrotron radiation in small-angle X-ray scattering (SAXS) techniques in biological structural studies is described. The main features of the monochromatic radiation systems and the white radiation systems are considered. The detectors, data acquisition and experimental procedures are briefly described. Experimental results are presented for 1) measurements on dilute solutions and weak scatterers, 2) measurement of conformational transitions, 3) contrast variation experiments, 4) time-resolved measurements and 5) complex contrast variation. (U.K.)

Progresses in the measurement and evaluation of small-angle x-ray scattering data

International Nuclear Information System (INIS)

Bergmann, A.

2000-08-01

Scattering methods are a widely used technique for determining size and shape of particles in the mesoscopic size range. This work deals on the one hand with the development of instruments in the field of Small Angle x-ray Scattering (SAXS) and on the other hand with methodical contributions concerning the interpretation of small angle scattering data. After a short introduction about Small Angle Scattering (SAS) and its application in chapter one, follows in chapter two a derivation of the theory of Small Angle x-ray scattering. Thereafter indirect transformations (Generalized Indirect Fourier Transformation [GIFT], Indirect Fourier Transformation [IFT]) are discussed and in this connection the optimization of multidimensional hyper surfaces is described. There are different possibilities for optimizing such multidimensional surfaces. The pros and contras of the different optimization methods with respect to the evaluation of small angle scattering data from interacting systems are discussed in detail. Global optimization methods are mainly used, if the hypersurface, which has to be optimized, shows many local minima. The goal of the optimization is it to find the global minimum. It is essential, that the parameters of the hyper surface are independent of each other, as it is the case in the GIFT. If someone deals with problems in only few dimensions or with many boundary conditions, mostly local optimization routines are sufficient. Therefore a number of starting parameters for the optimization is chosen, which can be obtained systematically or randomly. The best solution obtained represents the result of the optimization procedure. Chapter 3 deals with the description of instruments used in the field of Small Angle x-ray Scattering. After a description of the components (x-ray sources, monochromators, detectors) of these instruments, the different beam geometries are discussed. In chapter 4 improvements of SAXS measurements on Kratky slit systems by Goebel

Watching Nanoparticles Form: An In Situ (Small-/Wide-Angle X-ray Scattering/Total Scattering) Study of the Growth of Yttria-Stabilised Zirconia in Supercritical Fluids

DEFF Research Database (Denmark)

Tyrsted, Christoffer; Pauw, Brian; Jensen, Kirsten Marie Ørnsbjerg

2012-01-01

Understanding nanoparticle formation reactions requires multitechnique in situ characterisation, since no single characterisation technique provides adequate information. Here, the first combined small-angle X-ray scattering (SAXS)/wide-angle X-ray scattering (WAXS)/total-scattering study of nano...... of nanoparticle formation is presented. We report on the formation and growth of yttria-stabilised zirconia (YSZ) under the extreme conditions of supercritical methanol for particles with Y2O3 equivalent molar fractions of 0, 4, 8, 12 and 25%....

SAXS Study of Sterically Stabilized Lipid Nanocarriers Functionalized by DNA

Science.gov (United States)

Angelov, Borislav; Angelova, Angelina; Filippov, Sergey; Karlsson, Göran; Terrill, Nick; Lesieur, Sylviane; Štěpánek, Petr

2012-03-01

The structure of novel spontaneously self-assembled plasmid DNA/lipid complexes is investigated by means of synchrotron radiation small-angle X-ray scattering (SAXS) and Cryo-TEM imaging. Liquid crystalline (LC) hydrated lipid systems are prepared using the non-ionic lipids monoolein and DOPE-PEG2000 and the cationic amphiphile CTAB. The employed plasmid DNA (pDNA) is encoding for the human protein brain-derived neurotrophic factor (BDNF). A coexistence of nanoparticulate objects with different LC inner organizations is established. A transition from bicontinuous membrane sponges, cubosome intermediates and unilamelar liposomes to multilamellar vesicles, functionalized by pDNA, is favoured upon binding and compaction of pBDNF onto the cationic PEGylated lipid nanocarriers. The obtained sterically stabilized multicompartment nanoobjects, with confined supercoiled plasmid DNA (pBDNF), are important in the context of multicompartment lipid nanocarriers of interest for gene therapy of neurodegenerative diseases.

SAXS Study of Sterically Stabilized Lipid Nanocarriers Functionalized by DNA

International Nuclear Information System (INIS)

Angelov, Borislav; Filippov, Sergey; Štepánek, Petr; Angelova, Angelina; Lesieur, Sylviane; Karlsson, Göran; Terrill, Nick

2012-01-01

The structure of novel spontaneously self-assembled plasmid DNA/lipid complexes is investigated by means of synchrotron radiation small-angle X-ray scattering (SAXS) and Cryo-TEM imaging. Liquid crystalline (LC) hydrated lipid systems are prepared using the non-ionic lipids monoolein and DOPE-PEG 2000 and the cationic amphiphile CTAB. The employed plasmid DNA (pDNA) is encoding for the human protein brain-derived neurotrophic factor (BDNF). A coexistence of nanoparticulate objects with different LC inner organizations is established. A transition from bicontinuous membrane sponges, cubosome intermediates and unilamelar liposomes to multilamellar vesicles, functionalized by pDNA, is favoured upon binding and compaction of pBDNF onto the cationic PEGylated lipid nanocarriers. The obtained sterically stabilized multicompartment nanoobjects, with confined supercoiled plasmid DNA (pBDNF), are important in the context of multicompartment lipid nanocarriers of interest for gene therapy of neurodegenerative diseases.

Alzheimer's disease imaging biomarkers using small-angle x-ray scattering

Science.gov (United States)

Choi, Mina; Alam, Nadia; Dahal, Eshan; Ghammraoui, Bahaa; Badano, Aldo

2016-03-01

There is a need for novel imaging techniques for the earlier detection of Alzheimer's disease (AD). Two hallmarks of AD are amyloid beta (Aβ) plaques and tau tangles that are formed in the brain. Well-characterized x-ray cross sections of Aβ and tau proteins in a variety of structural states could potentially be used as AD biomarkers for small-angle x-ray scattering (SAXS) imaging without the need for injectable probes or contrast agents. First, however, the protein structures must be controlled and measured to determine accurate biomarkers for SAXS imaging. Here we report SAXS measurements of Aβ42 and tau352 in a 50% dimethyl sulfoxide (DMSO) solution in which these proteins are believed to remain monomeric because of the stabilizing interaction of DMSO solution. Our SAXS analysis showed the aggregation of both proteins. In particular, we found that the aggregation of Aβ42 slowly progresses with time in comparison to tau352 that aggregates at a faster rate and reaches a steady-state. Furthermore, the measured signals were compared to the theoretical SAXS profiles of Aβ42 monomer, Aβ42 fibril, and tau352 that were computed from their respective protein data bank structures. We have begun the work to systematically control the structural states of these proteins in vitro using various solvent conditions. Our future work is to utilize the distinct SAXS profiles of various structural states of Aβ and tau to build a library of signals of interest for SAXS imaging in brain tissue.

Chandra and XMM-Newton observations of the low-luminosity X-ray pulsators SAX J1324.4−6200 and SAX J1452.8−5949

NARCIS (Netherlands)

Kaur, R.; Wijnands, R.; Patruno, A.; Testa, V.; Israel, G.; Degenaar, N.; Paul, B.; Kumar, B.

2009-01-01

We present results from our Chandra and XMM-Newton observations of two low-luminosity X-ray pulsators SAX J1324.4-6200 and SAX J1452.8-5949 which have spin periods of 172 and 437 s, respectively. The XMM-Newton spectra for both sources can be fitted well with a simple power-law model of photon

Innovative High-Throughput SAXS Methodologies Based on Photonic Lab-on-a-Chip Sensors: Application to Macromolecular Studies.

Science.gov (United States)

Rodríguez-Ruiz, Isaac; Radajewski, Dimitri; Charton, Sophie; Phamvan, Nhat; Brennich, Martha; Pernot, Petra; Bonneté, Françoise; Teychené, Sébastien

2017-06-02

The relevance of coupling droplet-based Photonic Lab-on-a-Chip (PhLoC) platforms and Small-Angle X-Ray Scattering (SAXS) technique is here highlighted for the performance of high throughput investigations, related to the study of protein macromolecular interactions. With this configuration, minute amounts of sample are required to obtain reliable statistical data. The PhLoC platforms presented in this work are designed to allow and control an effective mixing of precise amounts of proteins, crystallization reagents and buffer in nanoliter volumes, and the subsequent generation of nanodroplets by means of a two-phase flow. Spectrophotometric sensing permits a fine control on droplet generation frequency and stability as well as on concentration conditions, and finally the droplet flow is synchronized to perform synchrotron radiation SAXS measurements in individual droplets (each one acting as an isolated microreactor) to probe protein interactions. With this configuration, droplet physic-chemical conditions can be reproducibly and finely tuned, and monitored without cross-contamination, allowing for the screening of a substantial number of saturation conditions with a small amount of biological material. The setup was tested and validated using lysozyme as a model of study. By means of SAXS experiments, the proteins gyration radius and structure envelope were calculated as a function of protein concentration. The obtained values were found to be in good agreement with previously reported data, but with a dramatic reduction of sample volume requirements compared to studies reported in the literature.

Combination of Microfluidics with SAXS for the investigation of pharmaceutical formulations

DEFF Research Database (Denmark)

Ghazal, Aghiad

Due to the latest advancements in microfluidics and synchrotron facilities, researchers started exploring the possibility of harnessing the benefits of combining both fields of science to address questions that were deemed unanswerable. Moreover, this combination made experiments that were believed......-ray inspired us to explore interesting nanoparticles that have been gaining interest in the recent years for drug delivery applications and bio-imaging. These drug nanocarriers are superior in terms of their efficiency in solubilizing various drugs and may help in controlling their release. They are lipid...... of efficient tools to investigate them thoroughly. Therefore, we became enthusiastic about performing mixing experiments on these nanoparticles using microfluidics while performing in situ characterization using synchrotron small angle X-ray scattering (SAXS). We were able to locate the time range at which...

On-Going Bentonite Pore Water Studies by NMR and SAXS

International Nuclear Information System (INIS)

Carlsson, Torbjoern; Muurinen, Arto; Root, Andrew

2013-01-01

Compacted water-saturated MX-80 bentonite is presently being studied by SAXS and NMR in order to quantify the major pore water phases in the bentonite. The SAXS and NMR measurements gave very similar results indicating that the pore water is mainly distributed between two major phases (interlayer and non-interlayer water) and also indicate how these phases depend on the bentonite dry density. The results from the SAXS and NMR studies at VTT indicate the same thing: - The pore water in water-saturated compacted (?dry = 0.7-1.6 g/cm 3 ) bentonite is divided into two main phases: interlayer water and non-interlayer water. - The amounts of these pore water phases can be determined quantitatively with the above methods. (authors)

Organically Modified Saponites: SAXS Study of Swelling and Application in Caffeine Removal.

Science.gov (United States)

Marçal, Liziane; de Faria, Emerson H; Nassar, Eduardo J; Trujillano, Raquel; Martín, Nuria; Vicente, Miguel A; Rives, Vicente; Gil, Antonio; Korili, Sophia A; Ciuffi, Katia J

2015-05-27

This study aimed to assess the capacity of saponite modified with n-hexadecyltrimethylammonium bromide (CTAB) and/or 3-aminopropyltriethoxysilane (APTS) to adsorb and remove caffeine from aqueous solutions. Powder X-ray diffraction (PXRD) revealed increased basal spacing in the modified saponites. Small-angle X-ray scattering (SAXS) confirmed the PXRD results; it also showed how the different clay layers were stacked and provided information on the swelling of natural saponite and of the saponites functionalized with CTAB and/or APTS. Thermal analyses, infrared spectroscopy, scanning electron microscopy, element chemical analysis, and textural analyses confirmed functionalization of the natural saponite. The maximum adsorption capacity at equilibrium was 80.54 mg/g, indicating that the saponite modified with 3-aminopropyltriethoxysilane constitutes an efficient and suitable caffeine adsorbent.

A novel application of small-angle scattering techniques: Quality assurance testing of virus quantification technology

International Nuclear Information System (INIS)

Kuzmanovic, Deborah A.; Elashvili, Ilya; O'Connell, Catherine; Krueger, Susan

2008-01-01

Small-angle scattering (SAS) techniques, like small-angle X-ray scattering (SAXS) and small-angle neutron scattering (SANS), were used to measure and thus to validate the accuracy of a novel technology for virus sizing and concentration determination. These studies demonstrate the utility of SAS techniques for use in quality assurance measurements and as novel technology for the physical characterization of viruses

Compositional studies at the Bone-Cartilage interface using PIXE, RBS and cSAXS techniques

International Nuclear Information System (INIS)

Kaabar, W.; Gundogdu, O.; Bradley, D.A.; Bunk, O.; Pfeiffer, F.; Pfeiffer, F.; Farquharson, M.J.; Webb, M.; Jeynes, C.

2009-01-01

Micro Proton Induced X-ray Emission (μ-PIXE) analysis has been employed herein in investigating and quantifying the distribution of a number of essential cations in two thin slices of normal and diseased human articular cartilage, the latter being affected by osteoarthritis (OA). The elemental distribution maps for Ca, P, K, S and Zn in the normal and diseased slices showed similar patterns with marked increases in elemental concentrations in the bone-cartilage interface. The S concentration was significantly lower in bone than in cartilage. Conversely, the Ca and P concentrations were higher in bone. The Ca/P ratio (2.22) of the diseased slice was determined by employing the Rutherford backscattering technique (RBS). The RBS figures of this investigation agree with values previously reported by others. Structural and organisational changes of collagen networks were investigated by coherent Small-Angle X-ray Scattering (SAXS) using beamline facilities at the Swiss Light Source (SLS) for a decalcified diseased human articular cartilage slice. The SAXS findings showed a gradual reorientation of collagen type II fibres of cartilage from parallel to the surface of the joint to normal to the bone-cartilage interface. Similar patterns of orientation were observed at the subchondral bone to bone-cartilage interface

A structural model of PpoA derived from SAXS-analysis-implications for substrate conversion.

Science.gov (United States)

Koch, Christian; Tria, Giancarlo; Fielding, Alistair J; Brodhun, Florian; Valerius, Oliver; Feussner, Kirstin; Braus, Gerhard H; Svergun, Dmitri I; Bennati, Marina; Feussner, Ivo

2013-09-01

In plants and mammals, oxylipins may be synthesized via multi step processes that consist of dioxygenation and isomerization of the intermediately formed hydroperoxy fatty acid. These processes are typically catalyzed by two distinct enzyme classes: dioxygenases and cytochrome P450 enzymes. In ascomycetes biosynthesis of oxylipins may proceed by a similar two-step pathway. An important difference, however, is that both enzymatic activities may be combined in a single bifunctional enzyme. These types of enzymes are named Psi-factor producing oxygenases (Ppo). Here, the spatial organization of the two domains of PpoA from Aspergillus nidulans was analyzed by small-angle X-ray scattering and the obtained data show that the enzyme exhibits a relatively flat trimeric shape. Atomic structures of the single domains were obtained by template-based structure prediction and docked into the enzyme envelope of the low resolution structure obtained by SAXS. EPR-based distance measurements between the tyrosyl radicals formed in the activated dioxygenase domain of the enzyme supported the trimeric structure obtained from SAXS and the previous assignment of Tyr374 as radical-site in PpoA. Furthermore, two phenylalanine residues in the cytochrome P450 domain were shown to modulate the specificity of hydroperoxy fatty acid rearrangement. Copyright © 2013 Elsevier B.V. All rights reserved.

BeppoSAX and Chandra Observations of SAX J0103.2-7209 = 2E 0101.5-7225: A New Persistent 345 Second X-Ray Pulsar in the Small Magellanic Cloud.

Science.gov (United States)

Israel; Campana; Covino; Dal Fiume D; Gaetz; Mereghetti; Oosterbroek; Orlandini; Parmar; Ricci; Stella

2000-03-10

We report the results of a 1998 July BeppoSAX observation of a field in the Small Magellanic Cloud which led to the discovery of approximately 345 s pulsations in the X-ray flux of SAX J0103.2-7209. The BeppoSAX X-ray spectrum is well fitted by an absorbed power law with a photon index of approximately 1.0 plus a blackbody component with kT=0.11 keV. The unabsorbed luminosity in the 2-10 keV energy range is approximately 1.2x1036 ergs s-1. In a very recent Chandra observation, the 345 s pulsations are also detected. The available period measurements provide a constant period derivative of -1.7 s yr-1 over the last 3 years, making SAX J0103.2-7209 one of the most rapidly spinning up X-ray pulsars known. The BeppoSAX position (30&arcsec; uncertainty radius) is consistent with that of the Einstein source 2E 0101.5-7225 and the ROSAT source RX J0103.2-7209. This source was detected at a luminosity level of a few times 1035-1036 ergs s-1 in all data sets of past X-ray missions since 1979. The ROSAT HRI and Chandra positions are consistent with that of a mV=14.8 Be spectral-type star already proposed as the likely optical counterpart of 2E 0101.5-7225. We briefly report and discuss photometric and spectroscopic data carried out at the ESO telescopes 2 days before the BeppoSAX observation. We conclude that SAX J0103.2-7209 and 2E 0101.5-7225 are the same source: a relatively young and persistent X-ray pulsar in the SMC.

Modeling the structure of RNA molecules with small-angle X-ray scattering data.

Directory of Open Access Journals (Sweden)

Michal Jan Gajda

Full Text Available We propose a novel fragment assembly method for low-resolution modeling of RNA and show how it may be used along with small-angle X-ray solution scattering (SAXS data to model low-resolution structures of particles having as many as 12 independent secondary structure elements. We assessed this model-building procedure by using both artificial data on a previously proposed benchmark and publicly available data. With the artificial data, SAXS-guided models show better similarity to native structures than ROSETTA decoys. The publicly available data showed that SAXS-guided models can be used to reinterpret RNA structures previously deposited in the Protein Data Bank. Our approach allows for fast and efficient building of de novo models of RNA using approximate secondary structures that can be readily obtained from existing bioinformatic approaches. We also offer a rigorous assessment of the resolving power of SAXS in the case of small RNA structures, along with a small multimetric benchmark of the proposed method.

Automated acquisition and analysis of small angle X-ray scattering data

International Nuclear Information System (INIS)

Franke, Daniel; Kikhney, Alexey G.; Svergun, Dmitri I.

2012-01-01

Small Angle X-ray Scattering (SAXS) is a powerful tool in the study of biological macromolecules providing information about the shape, conformation, assembly and folding states in solution. Recent advances in robotic fluid handling make it possible to perform automated high throughput experiments including fast screening of solution conditions, measurement of structural responses to ligand binding, changes in temperature or chemical modifications. Here, an approach to full automation of SAXS data acquisition and data analysis is presented, which advances automated experiments to the level of a routine tool suitable for large scale structural studies. The approach links automated sample loading, primary data reduction and further processing, facilitating queuing of multiple samples for subsequent measurement and analysis and providing means of remote experiment control. The system was implemented and comprehensively tested in user operation at the BioSAXS beamlines X33 and P12 of EMBL at the DORIS and PETRA storage rings of DESY, Hamburg, respectively, but is also easily applicable to other SAXS stations due to its modular design.

Microcrystallography, high-pressure cryocooling and BioSAXS at MacCHESS

Energy Technology Data Exchange (ETDEWEB)

Englich, Ulrich, E-mail: ue22@cornell.edu; Kriksunov, Irina A. [MacCHESS (Macromolecular Diffraction Facility at CHESS), Cornell University, Ithaca, NY 14853 (United States); Cerione, Richard A. [MacCHESS (Macromolecular Diffraction Facility at CHESS), Cornell University, Ithaca, NY 14853 (United States); Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY 14853 (United States); Cornell High Energy Synchrotron Source (CHESS), Cornell University, Ithaca, NY 14853 (United States); Cook, Michael J.; Gillilan, Richard [MacCHESS (Macromolecular Diffraction Facility at CHESS), Cornell University, Ithaca, NY 14853 (United States); Gruner, Sol M. [Field of Biophysics, Cornell University, Ithaca, NY 14853 (United States); Physics Department, Cornell University, Ithaca, NY 14853 (United States); Huang, Qingqui; Kim, Chae Un; Miller, William; Nielsen, Soren; Schuller, David; Smith, Scott; Szebenyi, Doletha M. E. [MacCHESS (Macromolecular Diffraction Facility at CHESS), Cornell University, Ithaca, NY 14853 (United States)

2011-01-01

Three research initiatives pursued by the Macromolecular Diffraction Facility at the Cornell High Energy Synchrotron Source (MacCHESS) are presented. The Macromolecular Diffraction Facility at the Cornell High Energy Synchrotron Source (MacCHESS) is a national research resource supported by the National Center for Research Resources of the US National Institutes of Health. MacCHESS is pursuing several research initiatives designed to benefit both CHESS users and the wider structural biology community. Three initiatives are presented in further detail: microcrystallography, which aims to improve the collection of diffraction data from crystals a few micrometers across, or small well diffracting regions of inhomogeneous crystals, so as to obtain high-resolution structures; pressure cryocooling, which can stabilize transient structures and reduce lattice damage during the cooling process; and BioSAXS (small-angle X-ray scattering on biological solutions), which can extract molecular shape and other structural information from macromolecules in solution.

Review of the fundamental theories behind small angle X-ray scattering, molecular dynamics simulations, and relevant integrated application

Directory of Open Access Journals (Sweden)

Lauren Boldon

2015-02-01

Full Text Available In this paper, the fundamental concepts and equations necessary for performing small angle X-ray scattering (SAXS experiments, molecular dynamics (MD simulations, and MD-SAXS analyses were reviewed. Furthermore, several key biological and non-biological applications for SAXS, MD, and MD-SAXS are presented in this review; however, this article does not cover all possible applications. SAXS is an experimental technique used for the analysis of a wide variety of biological and non-biological structures. SAXS utilizes spherical averaging to produce one- or two-dimensional intensity profiles, from which structural data may be extracted. MD simulation is a computer simulation technique that is used to model complex biological and non-biological systems at the atomic level. MD simulations apply classical Newtonian mechanics’ equations of motion to perform force calculations and to predict the theoretical physical properties of the system. This review presents several applications that highlight the ability of both SAXS and MD to study protein folding and function in addition to non-biological applications, such as the study of mechanical, electrical, and structural properties of non-biological nanoparticles. Lastly, the potential benefits of combining SAXS and MD simulations for the study of both biological and non-biological systems are demonstrated through the presentation of several examples that combine the two techniques.

Review of the fundamental theories behind small angle X-ray scattering, molecular dynamics simulations, and relevant integrated application.

Science.gov (United States)

Boldon, Lauren; Laliberte, Fallon; Liu, Li

2015-01-01

In this paper, the fundamental concepts and equations necessary for performing small angle X-ray scattering (SAXS) experiments, molecular dynamics (MD) simulations, and MD-SAXS analyses were reviewed. Furthermore, several key biological and non-biological applications for SAXS, MD, and MD-SAXS are presented in this review; however, this article does not cover all possible applications. SAXS is an experimental technique used for the analysis of a wide variety of biological and non-biological structures. SAXS utilizes spherical averaging to produce one- or two-dimensional intensity profiles, from which structural data may be extracted. MD simulation is a computer simulation technique that is used to model complex biological and non-biological systems at the atomic level. MD simulations apply classical Newtonian mechanics' equations of motion to perform force calculations and to predict the theoretical physical properties of the system. This review presents several applications that highlight the ability of both SAXS and MD to study protein folding and function in addition to non-biological applications, such as the study of mechanical, electrical, and structural properties of non-biological nanoparticles. Lastly, the potential benefits of combining SAXS and MD simulations for the study of both biological and non-biological systems are demonstrated through the presentation of several examples that combine the two techniques.

An apparatus for high speed measurements of small-angle x-ray scattering profiles with a linear position sensitive detector

International Nuclear Information System (INIS)

Hashimoto, Takeji; Suehiro, Shoji; Shibayama, Mitsuhiro; Saijo, Kenji; Kawai, Hiromichi

1981-01-01

An apparatus for high speed measurements of small-angle X-ray scattering (SAXS) is described. This apparatus utilizes a 12 kW rotating anode X-ray generator, a linear position sensitive proportional counter (multicathode delay line PSPC), and a two-parameter multichannel pulse height analyzer (MCA) with 12 kwords (16 bits/word) memory area available for SAXA intensity data as a function of position (scattering angles) and time slice. The two-parameter MCA is constructed within a microcomputer system, by utilizing its R/W memory for data storage, and the memory incrementing and real-time CRT display is implemented by using two direct memory access (DMA) controllers. The cycle time of the access is about 10 μs. The measuring time for SAXS profiles with this apparatus can be shortened approximately by three orders of magnitude in comparison with the measuring time with SAXS apparatuses utilizing a conventional step-scanning goniometer and a conventional X-ray tube, thus permitting time-resolved analyses of SAXS profiles. Some applications of the apparatus to dynamic SAXS measurements are presented for polymeric systems, the preliminary results of which seem to indicate the possibility of obtaining a new class of data on dynamics in structural transformation, deformation, formation and annihilation in the scale of a few tens to several hundred Angstroms. (author)

Quantitative analysis of inclusions in low carbon free cutting steel using small-angle X-ray and neutron scattering

International Nuclear Information System (INIS)

Oba, Yojiro; Koppoju, Suresh; Ohnuma, Masato; Kinjo, Yuki; Tomota, Yo; Morooka, Satoshi; Suzuki, Jun-ichi; Yamaguchi, Daisuke; Koizumi, Satoshi; Sato, Masugu; Shiraga, Tetsuo

2012-01-01

The microstructure of inclusions in low carbon free cutting steel without lead addition was investigated using small-angle X-ray scattering (SAXS) coupled with small-angle neutron scattering (SANS). The two-dimensional (2D) SAXS pattern shows clear scattering due to inclusions composed of large elongated particles aligned along the rolling direction, and small isotropic particles. From a comparison of the simulated and experimental 2D SAXS patterns, the shapes of the inclusions are regarded as ellipsoid for the larger inclusions and spherical for the smaller inclusions. The length of the minor axis in the large inclusion is 6.9 μm, while the diameter of the small inclusion is 0.50 μm. The aspect ratio of the large inclusion is estimated to be 3.8 in the lower q region, and is reduced slightly to 3.5 in the higher q region from the azimuthal plots. The results of an alloy contrast variation (ACV) analysis using both the SAXS and SANS data indicate that the chemical composition of the inclusions is almost NaCl-type manganese sulfide, and that the amount of iron sulfide is low. The volume fractions are 1.4% for the large inclusions and 0.2% for the small inclusions. This is consistent with the area fraction estimated using an optical microscope, and indicates that nearly all of the sulfur in the steel sample forms the manganese sulfide inclusions. (author)

Small-angle scattering in materials science

International Nuclear Information System (INIS)

Paris, O.; Fratzl, P.

1999-01-01

Small-angle scattering (SAS) of X-rays (SAXS) or neutrons (SANS) are a powerful tools to investigate inhomogeneities in the size range from ∼ 1 nm to ∼ 100 nm. Typical examples in materials science are pores, precipitates in metal alloys or nano-particles in composites. Frequently, these inhomogeneities are not spherical and their alignment is not random, quite in contrast to many other applications of SAS. This requires the use of pinhole geometry and area detectors for the experimental set-up. The present paper focuses on evaluation techniques of two-dimensional (2D) SAS-patterns from some materials investigated by the authors, i.e. metal alloys, carbon composites, wood and bone. Although the examples shown are derived exclusively from SAXS measurements, most of them could stem from SANS measurements as well. (author)

Investment Strategies Optimization based on a SAX-GA Methodology

CERN Document Server

Canelas, António M L; Horta, Nuno C G

2013-01-01

This book presents a new computational finance approach combining a Symbolic Aggregate approXimation (SAX) technique with an optimization kernel based on genetic algorithms (GA). While the SAX representation is used to describe the financial time series, the evolutionary optimization kernel is used in order to identify the most relevant patterns and generate investment rules. The proposed approach considers several different chromosomes structures in order to achieve better results on the trading platform The methodology presented in this book has great potential on investment markets.

Study of lamellar structure and crystallization behavior of poly(butylene terephthalate (PBT) in PBT/ABS and PBT/ABS/MMA-GMA blends using DSC, SAXS and DMTA

International Nuclear Information System (INIS)

Mantovani, Gerson L.; Pessan, Luiz A.; Hage, Elias; Torriani, Iris L.

2001-01-01

The effects of processing conditions and blend composition in the crystallization behaviour and lamellar structure of poly(butylene terephthalate) (PBT) in blends with acrylonitrile-butadiene-styrene copolymer (ABS) were studied. Differential scanning calorimetry (DSC), small-angle X-ray scattering (SAXS) and dynamic mechanical thermal analysis (DMTA) were used to observe those effects. Addition of reactive acrylic compatibilizer to the PBT/ABS blends has promoted an increase in the heat of crystallization of the related blends. The Long Period (L), obtained from the peak in the Lorentz-corrected SAXS pattern, was used to observe the effect in the lamellar structure of PBT phase in the blends. The results were in good agreement with the calculated values from de correlation function and the values of L do not show a significant dependence with the PBT mass fraction, either in the binary blends (PBT/ABS) or in the compatibilized blends. A slight but clear increase of the long period (from 3 to 5 angstrom) is noted for the systems injection molded at 240 deg C when compared to the ones molded at 260 deg C, although PBT crystallinity in the blends does not change significantly with blend composition or processing conditions. DMTA curves show a slight shift in the temperature of the tan δ main peaks for both PBT and ABS phases in the compatibilized blends, thereby indicating changes in the degree of miscibility or interaction between phases of those blends. Changes in the compatibilized blends miscibility may be responsible by the effects in the crystallization behaviour and lamellar structure of the PBT/ABS blends. (author)

Study of lamellar structure and crystallization behavior of poly(butylene terephthalate (PBT) in PBT/ABS and PBT/ABS/MMA-GMA blends using DSC, SAXS and DMTA

Energy Technology Data Exchange (ETDEWEB)

Mantovani, Gerson L.; Pessan, Luiz A.; Hage, Elias [Sao Carlos Univ., SP (Brazil). Dept. de Engenharia de Materiais]. E-mail: elias@power.ufscar.br; Plivelic, Tomas S. [Laboratorio Nacional de Luz Sincrotron (LNLS), Campinas, SP (Brazil); Torriani, Iris L. [Universidade Estadual de Campinas, SP (Brazil). Inst. de Fisica Gleb Wataghin

2001-07-01

The effects of processing conditions and blend composition in the crystallization behaviour and lamellar structure of poly(butylene terephthalate) (PBT) in blends with acrylonitrile-butadiene-styrene copolymer (ABS) were studied. Differential scanning calorimetry (DSC), small-angle X-ray scattering (SAXS) and dynamic mechanical thermal analysis (DMTA) were used to observe those effects. Addition of reactive acrylic compatibilizer to the PBT/ABS blends has promoted an increase in the heat of crystallization of the related blends. The Long Period (L), obtained from the peak in the Lorentz-corrected SAXS pattern, was used to observe the effect in the lamellar structure of PBT phase in the blends. The results were in good agreement with the calculated values from de correlation function and the values of L do not show a significant dependence with the PBT mass fraction, either in the binary blends (PBT/ABS) or in the compatibilized blends. A slight but clear increase of the long period (from 3 to 5 angstrom) is noted for the systems injection molded at 240 deg C when compared to the ones molded at 260 deg C, although PBT crystallinity in the blends does not change significantly with blend composition or processing conditions. DMTA curves show a slight shift in the temperature of the tan {delta} main peaks for both PBT and ABS phases in the compatibilized blends, thereby indicating changes in the degree of miscibility or interaction between phases of those blends. Changes in the compatibilized blends miscibility may be responsible by the effects in the crystallization behaviour and lamellar structure of the PBT/ABS blends. (author)

SAXS study of silica sols, gels and glasses obtained by the sol gel process

International Nuclear Information System (INIS)

Santos, D.I. dos; Aegerter, M.A.

1988-01-01

Systematic SAXS studies have been performed at the LURE Synchrotron, Orsay, using an intense beam of point like cross-section to obtain information about the sol -> humid gel -> dried gel -> silica glass transformation. The intensity curves have been analysed in term of power law in log-log plots, whose exponent is related to mass and surface fractal dimensions of the structure. It was found that almost all phases present fractal structures and for the case of basic gels, is of hierarchical nature. The aerogels are formed by a dense matrix, with a smooth surface and exhibit a very narrow auto-similarity range that gives a mass fractal dimension. (author) [pt

Discovery of 1-5 Hz flaring at high luminosity in SAX J1808.4-3658

Energy Technology Data Exchange (ETDEWEB)

Bult, Peter; Van der Klis, Michiel, E-mail: p.m.bult@uva.nl [Anton Pannekoek Institute, University of Amsterdam, Postbus 94249, 1090 GE Amsterdam (Netherlands)

2014-07-10

We report the discovery of a 1-5 Hz X-ray flaring phenomenon observed at >30 mCrab near peak luminosity in the 2008 and 2011 outbursts of the accreting millisecond X-ray pulsar SAX J1808.4-3658 in observations with the Rossi X-ray Timing Explorer. In each of the two outbursts this high luminosity flaring is seen for ∼3 continuous days and switches on and off on a timescale of 1-2 hr. The flaring can be seen directly in the light curve, where it shows sharp spikes of emission at quasi-regular separation. In the power spectrum it produces a broad noise component, which peaks at 1-5 Hz. The total 0.05-10 Hz variability has a fractional rms amplitude of 20%-45%, well in excess of the 8%-12% rms broadband noise usually seen in power spectra of SAX J1808.4-3658. We perform a detailed timing analysis of the flaring and study its relation to the 401 Hz pulsations. We find that the pulse amplitude varies proportionally with source flux through all phases of the flaring, indicating that the flaring is likely due to mass density variations created at or outside the magnetospheric boundary. We suggest that this 1-5 Hz flaring is a high mass accretion rate version of the 0.5-2 Hz flaring which is known to occur at low luminosity (<13 mCrab), late in the tail of outbursts of SAX J1808.4-3658. We propose the dead-disk instability, previously suggested as the mechanism for the 0.5-2 Hz flaring, as a likely mechanism for the high luminosity flaring reported here.

Compositional and structural studies of the bone-cartilage interface using PIXE and SAXS techniques

Energy Technology Data Exchange (ETDEWEB)

Kaabar, W., E-mail: W.kaabar@surrey.ac.u [Department of Physics, University of Surrey, Guildford, GU2 7XH (United Kingdom); Laklouk, A. [Al-Fateh University, Tripoli-Libya (Libyan Arab Jamahiriya); Bunk, O. [Swiss Light Source, Paul Scherrer Institute, 5232 Villigen (Switzerland); Baily, M. [Department of Medical Physics and Applied Radiation Sciences, McMaster University, 1280 Main Street West, Hamilton, Ontario, Canada, L8S 4K1 (Canada); Farquharson, M.J. [Surrey Ion Beam Centre, University of Surrey, Guildford, GU2 7XH (United Kingdom); Bradley, David [Department of Physics, University of Surrey, Guildford, GU2 7XH (United Kingdom)

2010-07-21

Micro-proton-induced X-ray emission ({mu}-PIXE) analysis has been employed in investigating the presence of number of essential anions and cations in thin sections of diseased human articular cartilage affected by osteoarthritis (OA). Distribution maps for Ca, P, K and S in diseased sections show marked alterations in the concentrations of these at the bone-cartilage interface compared to normal tissue. For a decalcified section of human articular cartilage, organisational changes of the collagen network were investigated by small-angle X-ray scattering (SAXS). The established gradual reorientation of collagen fibres from vertical to the surface of the joint to normal to the bone-cartilage interface is observed to be heavily disrupted in OA.

Compositional and structural studies of the bone-cartilage interface using PIXE and SAXS techniques

International Nuclear Information System (INIS)

Kaabar, W.; Laklouk, A.; Bunk, O.; Baily, M.; Farquharson, M.J.; Bradley, David

2010-01-01

Micro-proton-induced X-ray emission (μ-PIXE) analysis has been employed in investigating the presence of number of essential anions and cations in thin sections of diseased human articular cartilage affected by osteoarthritis (OA). Distribution maps for Ca, P, K and S in diseased sections show marked alterations in the concentrations of these at the bone-cartilage interface compared to normal tissue. For a decalcified section of human articular cartilage, organisational changes of the collagen network were investigated by small-angle X-ray scattering (SAXS). The established gradual reorientation of collagen fibres from vertical to the surface of the joint to normal to the bone-cartilage interface is observed to be heavily disrupted in OA.

Decoupling of size and shape fluctuations in heteropolymeric sequences reconciles discrepancies in SAXS vs. FRET measurements.

Science.gov (United States)

Fuertes, Gustavo; Banterle, Niccolò; Ruff, Kiersten M; Chowdhury, Aritra; Mercadante, Davide; Koehler, Christine; Kachala, Michael; Estrada Girona, Gemma; Milles, Sigrid; Mishra, Ankur; Onck, Patrick R; Gräter, Frauke; Esteban-Martín, Santiago; Pappu, Rohit V; Svergun, Dmitri I; Lemke, Edward A

2017-08-01

Unfolded states of proteins and native states of intrinsically disordered proteins (IDPs) populate heterogeneous conformational ensembles in solution. The average sizes of these heterogeneous systems, quantified by the radius of gyration ( R G ), can be measured by small-angle X-ray scattering (SAXS). Another parameter, the mean dye-to-dye distance ( R E ) for proteins with fluorescently labeled termini, can be estimated using single-molecule Förster resonance energy transfer (smFRET). A number of studies have reported inconsistencies in inferences drawn from the two sets of measurements for the dimensions of unfolded proteins and IDPs in the absence of chemical denaturants. These differences are typically attributed to the influence of fluorescent labels used in smFRET and to the impact of high concentrations and averaging features of SAXS. By measuring the dimensions of a collection of labeled and unlabeled polypeptides using smFRET and SAXS, we directly assessed the contributions of dyes to the experimental values R G and R E For chemically denatured proteins we obtain mutual consistency in our inferences based on R G and R E , whereas for IDPs under native conditions, we find substantial deviations. Using computations, we show that discrepant inferences are neither due to methodological shortcomings of specific measurements nor due to artifacts of dyes. Instead, our analysis suggests that chemical heterogeneity in heteropolymeric systems leads to a decoupling between R E and R G that is amplified in the absence of denaturants. Therefore, joint assessments of R G and R E combined with measurements of polymer shapes should provide a consistent and complete picture of the underlying ensembles.

An Optimized Table-Top Small-Angle X-ray Scattering Set-up for the Nanoscale Structural Analysis of Soft Matter

KAUST Repository

Sibillano, T.

2014-11-10

The paper shows how a table top superbright microfocus laboratory X-ray source and an innovative restoring-data algorithm, used in combination, allow to analyze the super molecular structure of soft matter by means of Small Angle X-ray Scattering ex-situ experiments. The proposed theoretical approach is aimed to restore diffraction features from SAXS profiles collected from low scattering biomaterials or soft tissues, and therefore to deal with extremely noisy diffraction SAXS profiles/maps. As biological test cases we inspected: i) residues of exosomes\\' drops from healthy epithelial colon cell line and colorectal cancer cells; ii) collagen/human elastin artificial scaffolds developed for vascular tissue engineering applications; iii) apoferritin protein in solution. Our results show how this combination can provide morphological/structural nanoscale information to characterize new artificial biomaterials and/or to get insight into the transition between healthy and pathological tissues during the progression of a disease, or to morphologically characterize nanoscale proteins, based on SAXS data collected in a room-sized laboratory.

An Optimized Table-Top Small-Angle X-ray Scattering Set-up for the Nanoscale Structural Analysis of Soft Matter

KAUST Repository

Sibillano, T.; De Caro, L.; Altamura, D.; Siliqi, D.; Ramella, M.; Boccafoschi, F.; Ciasca, G.; Campi, G.; Tirinato, Luca; Di Fabrizio, Enzo M.; Giannini, C.

2014-01-01

The paper shows how a table top superbright microfocus laboratory X-ray source and an innovative restoring-data algorithm, used in combination, allow to analyze the super molecular structure of soft matter by means of Small Angle X-ray Scattering ex-situ experiments. The proposed theoretical approach is aimed to restore diffraction features from SAXS profiles collected from low scattering biomaterials or soft tissues, and therefore to deal with extremely noisy diffraction SAXS profiles/maps. As biological test cases we inspected: i) residues of exosomes' drops from healthy epithelial colon cell line and colorectal cancer cells; ii) collagen/human elastin artificial scaffolds developed for vascular tissue engineering applications; iii) apoferritin protein in solution. Our results show how this combination can provide morphological/structural nanoscale information to characterize new artificial biomaterials and/or to get insight into the transition between healthy and pathological tissues during the progression of a disease, or to morphologically characterize nanoscale proteins, based on SAXS data collected in a room-sized laboratory.

An Optimized Table-Top Small-Angle X-ray Scattering Set-up for the Nanoscale Structural Analysis of Soft Matter

Science.gov (United States)

Sibillano, T.; de Caro, L.; Altamura, D.; Siliqi, D.; Ramella, M.; Boccafoschi, F.; Ciasca, G.; Campi, G.; Tirinato, L.; di Fabrizio, E.; Giannini, C.

2014-11-01

The paper shows how a table top superbright microfocus laboratory X-ray source and an innovative restoring-data algorithm, used in combination, allow to analyze the super molecular structure of soft matter by means of Small Angle X-ray Scattering ex-situ experiments. The proposed theoretical approach is aimed to restore diffraction features from SAXS profiles collected from low scattering biomaterials or soft tissues, and therefore to deal with extremely noisy diffraction SAXS profiles/maps. As biological test cases we inspected: i) residues of exosomes' drops from healthy epithelial colon cell line and colorectal cancer cells; ii) collagen/human elastin artificial scaffolds developed for vascular tissue engineering applications; iii) apoferritin protein in solution. Our results show how this combination can provide morphological/structural nanoscale information to characterize new artificial biomaterials and/or to get insight into the transition between healthy and pathological tissues during the progression of a disease, or to morphologically characterize nanoscale proteins, based on SAXS data collected in a room-sized laboratory.

Measurement of illite particle thickness using a direct Fourier transform of small-angle X-ray scattering data

Science.gov (United States)

Shang, Chao; Rice, James A.; Eberl, Dennis D.; Lin, Jar-Shyong

2003-01-01

It has been suggested that interstratified illite-smectite (I-S) minerals are composed of aggregates of fundamental particles. Many attempts have been made to measure the thickness of such fundamental particles, but each of the methods used suffers from its own limitations and uncertainties. Small-angle X-ray scattering (SAXS) can be used to measure the thickness of particles that scatter X-rays coherently. We used SAXS to study suspensions of Na-rectorite and other illites with varying proportions of smectite. The scattering intensity (I) was recorded as a function of the scattering vector, q = (4 /) sin(/2), where  is the X-ray wavelength and  is the scattering angle. The experimental data were treated with a direct Fourier transform to obtain the pair distance distribution function (PDDF) that was then used to determine the thickness of illite particles. The Guinier and Porod extrapolations were used to obtain the scattering intensity beyond the experimental q, and the effects of such extrapolations on the PDDF were examined. The thickness of independent rectorite particles (used as a reference mineral) is 18.3 Å. The SAXS results are compared with those obtained by X-ray diffraction peak broadening methods. It was found that the power-law exponent (α) obtained by fitting the data in the region of q = 0.1-0.6 nm-1 to the power law (I = I0q-α) is a linear function of illite particle thickness. Therefore, illite particle thickness could be predicted by the linear relationship as long as the thickness is within the limit where α <4.0.

A customizable software for fast reduction and analysis of large X-ray scattering data sets: applications of the new DPDAK package to small-angle X-ray scattering and grazing-incidence small-angle X-ray scattering.

Science.gov (United States)

Benecke, Gunthard; Wagermaier, Wolfgang; Li, Chenghao; Schwartzkopf, Matthias; Flucke, Gero; Hoerth, Rebecca; Zizak, Ivo; Burghammer, Manfred; Metwalli, Ezzeldin; Müller-Buschbaum, Peter; Trebbin, Martin; Förster, Stephan; Paris, Oskar; Roth, Stephan V; Fratzl, Peter

2014-10-01

X-ray scattering experiments at synchrotron sources are characterized by large and constantly increasing amounts of data. The great number of files generated during a synchrotron experiment is often a limiting factor in the analysis of the data, since appropriate software is rarely available to perform fast and tailored data processing. Furthermore, it is often necessary to perform online data reduction and analysis during the experiment in order to interactively optimize experimental design. This article presents an open-source software package developed to process large amounts of data from synchrotron scattering experiments. These data reduction processes involve calibration and correction of raw data, one- or two-dimensional integration, as well as fitting and further analysis of the data, including the extraction of certain parameters. The software, DPDAK (directly programmable data analysis kit), is based on a plug-in structure and allows individual extension in accordance with the requirements of the user. The article demonstrates the use of DPDAK for on- and offline analysis of scanning small-angle X-ray scattering (SAXS) data on biological samples and microfluidic systems, as well as for a comprehensive analysis of grazing-incidence SAXS data. In addition to a comparison with existing software packages, the structure of DPDAK and the possibilities and limitations are discussed.

New beamline dedicated to solution scattering from biological macromolecules at the ESRF

International Nuclear Information System (INIS)

Pernot, P; Theveneau, P; Giraud, T; Fernandes, R Nogueira; Nurizzo, D; Spruce, D; Surr, J; McSweeney, S; Round, A; Felisaz, F; Foedinger, L; Gobbo, A; Huet, J; Villard, C; Cipriani, F

2010-01-01

The new bio-SAXS beamline (ID14-3 at the ESRF, Grenoble, France) is dedicated exclusively to small-angle scattering experiments of biological macromolecules in solution and has been in user operation since November 2008. Originally a protein crystallography beamline, ID14-3 was refurbished, still as a part of the ESRF Structural Biology group, with the main aim to provide a facility with 'quick and easy' access to satisfy rapidly growing demands from crystallographers, biochemists and structural biologists. The beamline allows manual and automatic sample loading/unloading, data collection, processing (conversion of a 2D image to a normalized 1D X-ray scattering profile) and analysis. The users obtain on-line standard data concerning the size (radius of gyration, maximum dimension and volume) and molecular weight of samples which allow on-the fly ab-inito shape reconstruction in order to provide feedback enabling the data collection strategies to be optimized. Automation of sample loading is incorporated on the beamline using a device constructed in collaboration between the EMBL (Grenoble and Hamburg outstations) and the ESRF. Semi/automated data analysis is implemented following the model of the SAXS facility at X33, EMBL Hamburg. This paper describes the bio-SAXS beamline and set-up characteristics together with the examples of user data obtained.

Pseudomonas sax genes overcome aliphatic isothiocyanate-mediated non-host resistance in Arabidopsis

Science.gov (United States)

Jun Fan; Casey Crooks; Gary Creissen; Lionel Hill; Shirley Fairhurst; Peter Doerner; Chris Lamb

2011-01-01

Most plant-microbe interactions do not result in disease; natural products restrict non-host pathogens. We found that sulforaphane (4-methylsulfinylbutyl isothiocyanate), a natural product derived from aliphatic glucosinolates, inhibits growth in Arabidopsis of non-host Pseudomonas bacteria in planta. Multiple sax genes (saxCAB/F/D/G) were identified in Pseudomonas...

BioXTAS RAW: improvements to a free open-source program for small-angle X-ray scattering data reduction and analysis.

Science.gov (United States)

Hopkins, Jesse Bennett; Gillilan, Richard E; Skou, Soren

2017-10-01

BioXTAS RAW is a graphical-user-interface-based free open-source Python program for reduction and analysis of small-angle X-ray solution scattering (SAXS) data. The software is designed for biological SAXS data and enables creation and plotting of one-dimensional scattering profiles from two-dimensional detector images, standard data operations such as averaging and subtraction and analysis of radius of gyration and molecular weight, and advanced analysis such as calculation of inverse Fourier transforms and envelopes. It also allows easy processing of inline size-exclusion chromatography coupled SAXS data and data deconvolution using the evolving factor analysis method. It provides an alternative to closed-source programs such as Primus and ScÅtter for primary data analysis. Because it can calibrate, mask and integrate images it also provides an alternative to synchrotron beamline pipelines that scientists can install on their own computers and use both at home and at the beamline.

Small angle x-ray scattering as a potential tool for cancer diagnosis

International Nuclear Information System (INIS)

Kitchen, M.; Siu, K.K.W.; Lewis, R.A.

2003-01-01

Full text: The diagnostic potential of Small Angle X-ray Scattering (SAXS) patterns has recently been investigated for malignant breast tissues. The demonstrated systematic differences in the scattering signatures of malignant, benign and normal breast tissue specimens are believed to arise from the changes in the fibrous proteins making up the extracellular matrix (ECM) with the disease progression. The technique may also have the potential to aid in the diagnosis of gliomas, a highly aggressive type of brain tumour. Although complex and difficult to interpret, SAXS data from malignant tissues may prove to be a more effective classification tool than conventional histology techniques. Here we present the methodology of the technique, as applied to breast cancer and brain tumour specimens to date, and some directions for future investigations. We also present a novel analysis method, which employs wavelet decomposition and a naive Bayesian classifier, as a potential semi-automated classification tool

Vascular and molecular pharmacology of the metabolically stable CGRP analogue, SAX

DEFF Research Database (Denmark)

Sheykhzade, Majid; Abdolalizadeh, Bahareh; Koole, Cassandra

2018-01-01

receptors (CLR and RAMP1) were expressed in the artery. In rat cerebral membranes, binding affinities (pKi) of SAX and CGRP were 8.3 ± 0.19 and 9.3 ± 0.14. In human subcutaneous artery, SAX and CGRP induced vasodilation (pEC50 8.8 ± 0.18 and 9.5 ± 0.13), while pEC50s for cAMP production by human recombinant...

Dimensions and Global Twist of Single-Layer DNA Origami Measured by Small-Angle X-ray Scattering.

Science.gov (United States)

Baker, Matthew A B; Tuckwell, Andrew J; Berengut, Jonathan F; Bath, Jonathan; Benn, Florence; Duff, Anthony P; Whitten, Andrew E; Dunn, Katherine E; Hynson, Robert M; Turberfield, Andrew J; Lee, Lawrence K

2018-06-04

The rational design of complementary DNA sequences can be used to create nanostructures that self-assemble with nanometer precision. DNA nanostructures have been imaged by atomic force microscopy and electron microscopy. Small-angle X-ray scattering (SAXS) provides complementary structural information on the ensemble-averaged state of DNA nanostructures in solution. Here we demonstrate that SAXS can distinguish between different single-layer DNA origami tiles that look identical when immobilized on a mica surface and imaged with atomic force microscopy. We use SAXS to quantify the magnitude of global twist of DNA origami tiles with different crossover periodicities: these measurements highlight the extreme structural sensitivity of single-layer origami to the location of strand crossovers. We also use SAXS to quantify the distance between pairs of gold nanoparticles tethered to specific locations on a DNA origami tile and use this method to measure the overall dimensions and geometry of the DNA nanostructure in solution. Finally, we use indirect Fourier methods, which have long been used for the interpretation of SAXS data from biomolecules, to measure the distance between DNA helix pairs in a DNA origami nanotube. Together, these results provide important methodological advances in the use of SAXS to analyze DNA nanostructures in solution and insights into the structures of single-layer DNA origami.

Quantum-dot size and thin-film dielectric constant: precision measurement and disparity with simple models.

Science.gov (United States)

Grinolds, Darcy D W; Brown, Patrick R; Harris, Daniel K; Bulovic, Vladimir; Bawendi, Moungi G

2015-01-14

We study the dielectric constant of lead sulfide quantum dot (QD) films as a function of the volume fraction of QDs by varying the QD size and keeping the ligand constant. We create a reliable QD sizing curve using small-angle X-ray scattering (SAXS), thin-film SAXS to extract a pair-distribution function for QD spacing, and a stacked-capacitor geometry to measure the capacitance of the thin film. Our data support a reduced dielectric constant in nanoparticles.

GLOBAL MAPPING OF EARTH-LIKE EXOPLANETS FROM SCATTERED LIGHT CURVES

International Nuclear Information System (INIS)

Kawahara, Hajime; Fujii, Yuka

2010-01-01

Scattered lights from terrestrial exoplanets provide valuable information about their planetary surface. Applying the surface reconstruction method proposed by Fujii et al. to both diurnal and annual variations of scattered light, we develop a reconstruction method of land distribution with both longitudinal and latitudinal resolutions. We find that one can recover a global map of an idealized Earth-like planet on the following assumptions: (1) cloudlessness, (2) a face-on circular orbit, (3) known surface types and their reflectance spectra, (4) lack of atmospheric absorption, (5) known rotation rate, (6) a static map, and (7) the absence of a moon. Using the dependence of light curves on planetary obliquity, we also show that the obliquity can be measured by adopting the χ 2 minimization or the extended information criterion. We demonstrate the feasibility of our methodology by applying it to a multi-band photometry of a cloudless model Earth with future space missions such as the occulting ozone observatory (O3). We conclude that future space missions can estimate both the surface distribution and the obliquity at least for cloudless Earth-like planets within 5 pc.

BeppoSAX Observations of MKN 110

Science.gov (United States)

Nicastro, Fabrizio; Oliversen, Ronald J. (Technical Monitor)

2002-01-01

Mkn 110 is a bright, nearby Seyfert 1 galaxy, which underwent a long optical monitoring campaign, during the past 12 years. Optical observations show that Mkn 110 vary, both in flux and spectral shape. The intensity and width of its Broad Emission Lines (BELs) also vary, from typical Seyfert 1, to typical Narrow Line Seyfert 1 (NLSyl) values, so suggesting that this could be the first supermassive black holes where accretion state related transitions, as frequently observed in stellar-size black holes, have finally been observed. To verify these suggestions we asked to monitor Mkn 110 with BeppoSAX with three 50 ksec observations six months apart. The goal of the proposal was to observe spectral variations in X-ray, already suggested by previous, existing ROSAT (Roentgen Satellite) and ASCA (Advanced Satellite for Cosmology and Astrophysics) observations of the same source. The first of these three SAX (Satellite per Astronomia X) observations was taken on May 2000, and lacks the Low-Energy instrument (0.1-2 keV is the band in which NLSy1 and Sy1 X-ray spectra differ most).

SAXS study on activated carbons

International Nuclear Information System (INIS)

Bota, A.; Heringer, D.; Mihalffy, T.

1999-01-01

SAXS fractal analysis of activated carbons is presented. It gives very useful information about the structural changes of the carbon skeleton. From the fact, that the sequence of the activation and the heat treatment affect the fractal behaviours more drastically than the particle size distribution of the structural units, it follows that all changes in the pore and matrix structure may reduce principally to the bonding of the crystallite units. (K.A.)

Routine plasma analysis for 2-[18F]fluorotyrosine by SAX-cartridges

International Nuclear Information System (INIS)

Kling, P.; Coenen, H.H.; Stoecklin, G.

1990-01-01

There is a great necessity for simple, reliable, and fast methods of plasma analysis. While HPLC is generally the most effective method, it is rather time consuming and expensive in a routine setting with numerous plasma samples. The authors have developed a new method for determination of the amino acid analogue 2-[ 18 F]fluorotyrosine using SAX columns (Adsorbex R SAX, 400 mg, Merck). The results obtained agree within 5% with those determined by reverse phase HPLC

New Insights into Lamellar Structure Development and SAXS/WAXD Sequence Appearance During Uniaxial Stretching of Amorphous Poly(ethylene terephthalate) Above Glass Transition Temperature

Energy Technology Data Exchange (ETDEWEB)

Kawakami,D.; Burger, C.; Ran, S.; Avila-Orta, C.; Sics, I.; Chu, B.; Chiao, S.; Hsiao, B.; Kikutani, T.

2008-01-01

An in situ study of structure formation in amorphous poly(ethylene terephthalate) (PET) during uniaxial stretching at a temperature 30 C above glass transition temperature was carried out using synchrotron small-angle X-ray scattering (SAXS) and wide-angle X-ray diffraction (WAXD) techniques. Three major deformation-induced structure transitions were confirmed. (1) At small strains, the applied load increased initially but leveled off afterward. Sporadic isotropic crystallization without preferred orientation was observed by WAXD, where no hierarchical structure was seen by SAXS. (2) At intermediate strains, strain hardening took place. Although WAXD showed persistent progression of isotropic crystallization, SAXS indicated formation of a layered structure as well as a fibrillar domain in large scale. This behavior is not consistent with the mechanisms for shish-kebab or spinodal-assisted structure formation. Instead, it can be explained by flow-induced demixing of crystal and amorphous phases through layerlike flocking motion perpendicular to the stretching direction. (3) At high strains, the ratio between the applied load and strain was about constant. In this stage, crystal reorientation and lateral crystal growth took place. The corresponding structure changes could be categorized into three subregions. In the first region, the (010) crystalline plane began to orient. In the second region, the (100) crystalline plane began to orient. In the last region, the structure change became stable and the sample eventually broke apart.

Structural characterization of the phospholipid stabilizer layer at the solid-liquid interface of dispersed triglyceride nanocrystals with small-angle x-ray and neutron scattering

Science.gov (United States)

Schmiele, Martin; Schindler, Torben; Unruh, Tobias; Busch, Sebastian; Morhenn, Humphrey; Westermann, Martin; Steiniger, Frank; Radulescu, Aurel; Lindner, Peter; Schweins, Ralf; Boesecke, Peter

2013-06-01

Dispersions of crystalline nanoparticles with at least one sufficiently large unit cell dimension can give rise to Bragg reflections in the small-angle scattering range. If the nanocrystals possess only a small number of unit cells along these particular crystallographic directions, the corresponding Bragg reflections will be broadened. In a previous study of phospholipid stabilized dispersions of β-tripalmitin platelets [Unruh, J. Appl. Crystallogr.JACGAR0021-889810.1107/S0021889807044378 40, 1008 (2007)], the x-ray powder pattern simulation analysis (XPPSA) was developed. The XPPSA method facilitates the interpretation of the rather complicated small-angle x-ray scattering (SAXS) curves of such dispersions of nanocrystals. The XPPSA method yields the distribution function of the platelet thicknesses and facilitates a structural characterization of the phospholipid stabilizer layer at the solid-liquid interface between the nanocrystals and the dispersion medium from the shape of the broadened 001 Bragg reflection. In this contribution an improved and extended version of the XPPSA method is presented. The SAXS and small-angle neutron scattering patterns of dilute phospholipid stabilized tripalmitin dispersions can be reproduced on the basis of a consistent simulation model for the particles and their phospholipid stabilizer layer on an absolute scale. The results indicate a surprisingly flat arrangement of the phospholipid molecules in the stabilizer layer with a total thickness of only 12 Å. The stabilizer layer can be modeled by an inner shell for the fatty acid chains and an outer shell including the head groups and additional water. The experiments support a dense packing of the phospholipid molecules on the nanocrystal surfaces rather than isolated phospholipid domains.

Time-Resolved SAXS/WAXS Study of the Phase Behavior and Microstructural Evolution of Drug/PEG Solid Dispersions

International Nuclear Information System (INIS)

Zhu, Qing; Harris, Michael T.; Taylor, Lynne S.

2011-01-01

Simultaneous small-angle X-ray scattering/wide-angle X-ray scattering (SAXS/WAXS) was employed to elucidate the physical state and location of various small molecule drugs blended with polyethylene glycol (PEG), as well as the time dependent microstructural evolution of the systems. Samples were prepared by comelting physical mixtures of the drug and PEG, followed by solidification at 25 C. The model drugs selected encompassed a wide variety of physicochemical properties in terms of crystallization tendency and potential for interaction with PEG. It was observed that compounds which crystallized rapidly and had weak interactions with PEG tended to be excluded from the interlamellar region of the PEG matrix. In contrast, drugs which had favorable interactions with PEG were incorporated into the interlamellar regions of the polymer up until the point at which the drug crystallized whereby phase separation occurred. These factors are likely to impact the effectiveness of drug/PEG systems as drug delivery systems.

Extruded blend films of poly(vinyl alcohol) and polyolefins: common and hard-elastic nanostructure evolution in the polyolefin during straining as monitored by SAXS

International Nuclear Information System (INIS)

Stribeck, Norbert; Zeinolebadi, Ahmad; Fakirov, Stoyko; Bhattacharyya, Debes; Botta, Stephan

2013-01-01

Straining of PVA/PE and PVA/PP blends (70:30) is monitored by small-angle x-ray scattering (SAXS). Sheet-extruded films with different predraw ratio are investigated. The discrete SAXS of predrawn samples originates from polyolefin nanofibrils inside of polyolefin microfibrils immersed in a PVA matrix. PE nanofibrils deform less than the macroscopic strain without volume change. PP nanofibrils experience macroscopic strain. They lengthen but their diameter does not decrease. This is explained by strain-induced crystallization of PP from an amorphous depletion shell around the core of the nanofibril. The undrawn PVA/PE film exhibits isotropic semicrystalline nanostructure. Undrawn PVA/PP holds PP droplets containing oriented stacks of semicrystalline PP like neat precursors of hard-elastic thermoplasts. Respective predrawn films are softer than the undrawn material, indicating conversion into the hard-elastic state. Embedding of the polyolefin significantly retards neck formation. The polyolefin microfibrils can easily be extracted from the water-soluble matrix. (paper)

Application of small-angle X-ray scattering for differentiation among breast tumors

International Nuclear Information System (INIS)

Changizi, V.; Kheradmand, A. Arab; Oghabian, M.A.

2008-01-01

Small-angle X-ray scattering (SAXS) is an X-ray diffraction-based technique where a narrow collimated beam of X-rays is focused onto a sample and the scattered X-rays recorded by a detector. The pattern of the scattered X-rays carries information on the molecular structure of the material. As breast cancer is the most widespread cancer in women and differentiation among its tumors is important, this project compared the results of coherent X-ray scattering measurements obtained from benign and malignant breast tissues. The energy-dispersive method with a setup including X-ray tube, primary collimator, sample holder, secondary collimator and high-purity germanium (HpGe) detector was used. One hundred thirty-one breast-tissue samples, including normal, fibrocystic changes and carcinoma, were studied at the 6 deg scattering angle. Diffraction profiles (corrected scattered intensity versus momentum transfer) of normal, fibrocystic changes and carcinoma were obtained. These profiles showed a few peak positions for adipose (1.15 ± 0.06 nm -1 ), mixed normal (1.15 ± 0.06 nm -1 and 1.4 ± 0.04 nm -1 ), fibrocystic changes (1.46 ± 0.05 nm -1 and 1.74 ± 0.04 nm -1 ) and carcinoma (1.55 ± 0.04 nm -1 , 1.73 ± 0.06 nm -1 , 1.85 ± 0.05 nm -1 ). We were able to differentiate between normal, fibrocystic changes (benign) and carcinoma (malignant) breast tissues by SAXS. However, we were unable to differentiate between different types of carcinoma. (author)

Application of small-angle X-ray scattering for differentiation among breast tumors

Directory of Open Access Journals (Sweden)

Changizi V

2008-01-01

Full Text Available Small-angle X-ray scattering (SAXS is an X-ray diffraction-based technique where a narrow collimated beam of X-rays is focused onto a sample and the scattered X-rays recorded by a detector. The pattern of the scattered X-rays carries information on the molecular structure of the material. As breast cancer is the most widespread cancer in women and differentiation among its tumors is important, this project compared the results of coherent X-ray scattering measurements obtained from benign and malignant breast tissues. The energy-dispersive method with a setup including X-ray tube, primary collimator, sample holder, secondary collimator and high-purity germanium (HpGe detector was used. One hundred thirty-one breast-tissue samples, including normal, fibrocystic changes and carcinoma, were studied at the 6° scattering angle. Diffraction profiles (corrected scattered intensity versus momentum transfer of normal, fibrocystic changes and carcinoma were obtained. These profiles showed a few peak positions for adipose (1.15 ± 0.06 nm -1 , mixed normal (1.15 ± 0.06 nm -1 and 1.4 ± 0.04 nm -1 , fibrocystic changes (1.46 ± 0.05 nm -1 and 1.74 ± 0.04 nm -1 and carcinoma (1.55 ± 0.04 nm -1 , 1.73 ± 0.06 nm -1 , 1.85 ± 0.05 nm -1 . We were able to differentiate between normal, fibrocystic changes (benign and carcinoma (malignant breast tissues by SAXS. However, we were unable to differentiate between different types of carcinoma.

A Mo-anode-based in-house source for small-angle X-ray scattering measurements of biological macromolecules

Energy Technology Data Exchange (ETDEWEB)

Bruetzel, Linda K.; Fischer, Stefan; Salditt, Annalena; Sedlak, Steffen M.; Nickel, Bert; Lipfert, Jan, E-mail: Jan.Lipfert@lmu.de [Department of Physics, Nanosystems Initiative Munich, and Center for Nanoscience, Ludwig-Maximilians-University Munich, Amalienstr. 54, 80799 Munich, Germany and Geschwister-Scholl Platz 1, 80539 Munich (Germany)

2016-02-15

We demonstrate the use of a molybdenum-anode-based in-house small-angle X-ray scattering (SAXS) setup to study biological macromolecules in solution. Our system consists of a microfocus X-ray tube delivering a highly collimated flux of 2.5 × 10{sup 6} photons/s at a beam size of 1.2 × 1.2 mm{sup 2} at the collimation path exit and a maximum beam divergence of 0.16 mrad. The resulting observable scattering vectors q are in the range of 0.38 Å{sup −1} down to 0.009 Å{sup −1} in SAXS configuration and of 0.26 Å{sup −1} up to 5.7 Å{sup −1} in wide-angle X-ray scattering (WAXS) mode. To determine the capabilities of the instrument, we collected SAXS data on weakly scattering biological macromolecules including proteins and a nucleic acid sample with molecular weights varying from ∼12 to 69 kDa and concentrations of 1.5–24 mg/ml. The measured scattering data display a high signal-to-noise ratio up to q-values of ∼0.2 Å{sup −1} allowing for an accurate structural characterization of the samples. Moreover, the in-house source data are of sufficient quality to perform ab initio 3D structure reconstructions that are in excellent agreement with the available crystallographic structures. In addition, measurements for the detergent decyl-maltoside show that the setup can be used to determine the size, shape, and interactions (as characterized by the second virial coefficient) of detergent micelles. This demonstrates that the use of a Mo-anode based in-house source is sufficient to determine basic geometric parameters and 3D shapes of biomolecules and presents a viable alternative to valuable beam time at third generation synchrotron sources.

A new outburst of the recurrent neutron star transient SAX J1747.0-2853

NARCIS (Netherlands)

Brandt, S.; Chenevez, J.; Kuulkers, E.; Natalucci, L.; Fiocchi, M.T.; Tarana, A.; Shaw, S.; Beckmann, V.; Courvoisier, T.J.L.; Domingo, A.; Ebisawa, K.; Kretschmar, P.J.P.; Markwardt, C.; Oosterbroek, T.; Paizis, A.; Risquez, D.; Sanchez-Fernandez, C.; Wijnands, R.

2007-01-01

The recurrent transient neutron star system SAX J1747.0-2853 has in the past shown various outbursts with about 60 days duration. Recent observations with INTEGRAL reveal that SAX J1747.0-2853 shows increased activity which may mark the beginning of a new outburst. During the INTEGRAL Galactic Bulge

Degradation of periodic multilayers as seen by small-angle x-ray scattering and x-ray diffraction

CERN Document Server

Rafaja, D; Simek, D; Zdeborova, L; Valvoda, V

2002-01-01

The capabilities of small-angle x-ray scattering (SAXS) and wide-angle x-ray diffraction (XRD) to recognize structural changes in periodic multilayers were compared on Fe/Au multilayers with different degrees of structural degradation. Experimental results have shown that both methods are equally sensitive to the multilayer degradation, i.e., to the occurrence of non-continuous interfaces, to short-circuits in the multilayer structure and to the multilayer precipitation. XRD yielded additional information on the multilayer crystallinity, whilst SAXS could better recognize fragments of a long-range periodicity (remnants of the original multilayer structure). Changes in the multilayer structure were initiated by successive annealing at 200 and 300 deg. C. Experimental data were complemented by numerical simulations performed using a combination of optical theory and the distorted wave Born approximation for SAXS or the kinematical Born approximation for XRD.

The applications of small-angle X-ray scattering in studying nano-scaled polyoxometalate clusters in solutions

Science.gov (United States)

Li, Mu; Zhang, Mingxin; Wang, Weiyu; Cheng, Stephen Z. D.; Yin, Panchao

2018-05-01

Nano-scaled polyoxometalates (POMs) clusters with sizes ranging from 1 to 10 nm attract tremendous attention and have been extensively studied due to POMs' fascinating structural characteristics and prospects for wide-ranging applications. As a unique class of nanoparticles with well-defined structural topologies and monodispersed masses, the structures and properties of POMs in both bulk state and solutions have been explored with several well-developed protocols. Small-angle X-ray scattering (SAXS) technique, as a powerful tool for studying polymers and nanoparticles, has been recently extended to the investigating of solution behaviors of POMs. In this mini-review, the general principle and typical experimental procedures of SAXS are illustrated first. The applications of SAXS in characterizing POMs' morphology, counterion distribution around POMs, and short-range interactions among POMs in solutions are highlighted. [Figure not available: see fulltext.

Structural characterization of cellulosic materials using x-ray and neutron scattering

Energy Technology Data Exchange (ETDEWEB)

Penttila, P.

2013-11-01

Cellulosic biomass can be used as a feedstock for sustainable production of biofuels and various other products. A complete utilization of the raw material requires understanding on its structural aspects and their role in the various processes. In this thesis, x-ray and neutron scattering methods were applied to study the structure of various cellulosic materials and how they are affected in different processes. The obtained results were reviewed in the context of a model for the cellulose nanostructure. The dimensions of cellulose crystallites and the crystallinity were determined with wide-angle x-ray scattering (WAXS), whereas the nanoscale fibrillar structure of cellulose was characterized with small-angle x-ray and neutron scattering (SAXS and SANS). The properties determined with the small-angle scattering methods included specific surface areas and distances characteristic of the packing of cellulose microfibrils. Also other physical characterization methods, such as x-ray microtomography, infrared spectroscopy, and solid-state NMR were utilized in this work. In the analysis of the results, a comprehensive understanding of the structural changes throughout a range of length scales was aimed at. Pretreatment of birch sawdust by pressurized hot water extraction was observed to increase the crystal width of cellulose, as determined with WAXS, even though the cellulose crystallinity was slightly decreased. A denser packing of microfibrils caused by the removal of hemicelluloses and lignin in the extraction was evidenced by SAXS. This resulted in the opening of new pores between the microfibril bundles and an increase of the specific surface area. Enzymatic hydrolysis of microcrystalline cellulose (MCC) did not lead to differences in the average crystallinity or crystal size of the hydrolysis residues, which was explained to be caused by limitations due to the large size of the enzymes as compared to the pores inside the fibril aggregates. The SAXS intensities

Non-regularized inversion method from light scattering applied to ferrofluid magnetization curves for magnetic size distribution analysis

International Nuclear Information System (INIS)

Rijssel, Jos van; Kuipers, Bonny W.M.; Erné, Ben H.

2014-01-01

A numerical inversion method known from the analysis of light scattering by colloidal dispersions is now applied to magnetization curves of ferrofluids. The distribution of magnetic particle sizes or dipole moments is determined without assuming that the distribution is unimodal or of a particular shape. The inversion method enforces positive number densities via a non-negative least squares procedure. It is tested successfully on experimental and simulated data for ferrofluid samples with known multimodal size distributions. The created computer program MINORIM is made available on the web. - Highlights: • A method from light scattering is applied to analyze ferrofluid magnetization curves. • A magnetic size distribution is obtained without prior assumption of its shape. • The method is tested successfully on ferrofluids with a known size distribution. • The practical limits of the method are explored with simulated data including noise. • This method is implemented in the program MINORIM, freely available online

Automated microfluidic sample-preparation platform for high-throughput structural investigation of proteins by small-angle X-ray scattering

DEFF Research Database (Denmark)

Lafleur, Josiane P.; Snakenborg, Detlef; Nielsen, Søren Skou

2011-01-01

A new microfluidic sample-preparation system is presented for the structural investigation of proteins using small-angle X-ray scattering (SAXS) at synchrotrons. The system includes hardware and software features for precise fluidic control, sample mixing by diffusion, automated X-ray exposure...... control, UV absorbance measurements and automated data analysis. As little as 15 l of sample is required to perform a complete analysis cycle, including sample mixing, SAXS measurement, continuous UV absorbance measurements, and cleaning of the channels and X-ray cell with buffer. The complete analysis...

SAXS studies of the injection molding effects on the nanostructure of polyesters. II: polytrimetylene terephthalate (PTT)

International Nuclear Information System (INIS)

Marinelli, Alessandra L.; Plivelic, Tomas; Torriani, Iris; Bretas, Rosario E.S.

2005-01-01

In this work, the nanoperiodicity of some PTT samples, injection molded at different conditions, was evaluated as a function of the thickness of the samples. From the small angle X-ray scattering (SAXS) results, it was possible to observe that, as expected, there is a gradient of the L and lc values found through the thickness of the PTT samples. It was also found that at the center of the PTT sample injection molded at low injection temperature, Ti, the crystallinity degree evaluated previously by wide angle X-ray diffraction (WAXD) is high and the orientation in this region must be also high, because smaller values of L and l C were found at this region of the sample. The opposite trend was found to PBT.(author)

Dynein and EFF-1 control dendrite morphology by regulating the localization pattern of SAX-7 in epidermal cells.

Science.gov (United States)

Zhu, Ting; Liang, Xing; Wang, Xiang-Ming; Shen, Kang

2017-12-01

Our previous work showed that the cell adhesion molecule SAX-7 forms an elaborate pattern in Caenorhabditis elegans epidermal cells, which instructs PVD dendrite branching. However, the molecular mechanism forming the SAX-7 pattern in the epidermis is not fully understood. Here, we report that the dynein light intermediate chain DLI-1 and the fusogen EFF-1 are required in epidermal cells to pattern SAX-7. While previous reports suggest that these two molecules act cell-autonomously in the PVD, our results show that the disorganized PVD dendritic arbors in these mutants are due to the abnormal SAX-7 localization patterns in epidermal cells. Three lines of evidence support this notion. First, the epidermal SAX-7 pattern was severely affected in dli-1 and eff-1 mutants. Second, the abnormal SAX-7 pattern was predictive of the ectopic PVD dendrites. Third, expression of DLI-1 or EFF-1 in the epidermis rescued both the SAX-7 pattern and the disorganized PVD dendrite phenotypes, whereas expression of these molecules in the PVD did not. We also show that DLI-1 functions cell-autonomously in the PVD to promote distal branch formation. These results demonstrate the unexpected roles of DLI-1 and EFF-1 in the epidermis in the control of PVD dendrite morphogenesis. © 2017. Published by The Company of Biologists Ltd.

SAX J2103.5+4545 in outburst

DEFF Research Database (Denmark)

Galis, R.; Beckmann, V.; Bianchin, V.

2008-01-01

We report an intense hard X-ray outburst detected from the Be/ neutron star HMXB SAX J2103.5+4545 (Blay et al. 2004, A&A, 427, 293), which is known to be a pulsar. The source was detected during INTEGRAL observations of the Galactic Plane in the Cygnus region, starting at 2007-04-25T09:14 (UTC...

Effect of Cobalt Fillers on Polyurethane Segmentations Investigated by Synchrotron Small Angle X-Ray Scattering

Directory of Open Access Journals (Sweden)

Krit Koyvanich

2013-01-01

Full Text Available The segmentation between rigid and rubbery chains in polyurethanes (PUs influences polymeric properties and implementations. Several models have successfully been proposed to visualize the configuration between the hard segment (HS and soft segment (SS. For particulate PU composites, the arrangement of HS and SS is more complicated because the fillers tend to disrupt the chain formation and segmentation. In this work, the effect of ferromagnetic cobalt (Co powders (average diameter 2 μm on PU synthesized from a reaction between polyether polyol (soft segment and diphenylmethane-4,4′-diisocyanate (hard segment was studied with varying loadings (0, 20, 40, and 60 wt.%. The 300 μm thick PU/Co samples were tape-casted and then received heat treatment at 80°C for 180 min. From synchrotron small angle X-ray scattering (SAXS, the plot of the X-ray scattering intensity (I against the scattering vector (q exhibited a typical single peak of PU whose intensity was reduced by the increase in the Co loading. Characteristic SAXS peaks in the case of 0-20 wt.% Co agreed well with the scattering by globular hard segment domains according to Zernike-Prins and Percus-Yevick models. The higher Co loadings led to larger deviations from all theoretical models.

Vesicle formation in the block copolymer/ homopolymer mixture studied by scattering methods

International Nuclear Information System (INIS)

Koizumi, Satoshi; Hasegawa, Hirokazu; Hashimoto, Takeji; Suzuki, Junnich.

1993-01-01

We studied morphology and spatial segmental distribution of particular binary mixtures of poly(styrene-block-isoprene)(SI) and homopolystyren, either protonated (HS) or deuterated (DS), with small angle-X-ray scattering (SAXS) and neutron scattering (SANS). The block copolymer SI used itself had a lamellar microdomain. Molecular weights of HS and DS were identical to each other and equal also to that of polystyrene block (PS) in SI. SAXS results obtained for SI and HS mixtures show that: (1) HS is solubilized in the PS microdomains; (2) the polyisoprene lamella has the thickness independent of w HS , weight fraction of HS, but its undulation depends on w HS . These two findings, in turn, imply that the HS added is localized in the middle of the PS microdomains, i.e., in between the PS brushes emanating from the interface of SI. We further confirmed this implication by SANS with a deuterium labeling technique; the DS segments studied for the SI/DS mixture is localized in the middle of PS microdomain with the penetration depth of 10 nm between DS and PS block chains. (author)

Identifying low and high density amorphous phases during zeolite amorphisation using small and wide angle X-ray scattering

International Nuclear Information System (INIS)

Meneau, F.; Greaves, G.N.

2005-01-01

In situ experiments following the thermal amorphisation of zeolites reveal massive increases in small angle X-ray scattering (SAXS), persisting well beyond the stage where wide angle X-ray scattering (WAXS) can detect that any crystalline phase is present. This heterogeneity in the amorphised phase is attributed to the transition from a low density amorphous phase (LDA) to a high density amorphous phase (HDA) at the glass transition. The fractions of zeolite, LDA and HDA phases obtained from SAXS analysis are discussed in the context of non-linear changes detected in 29 Si solid state NMR during zeolite amorphisation. Whilst the HDA phase is chemically disordered, the LDA phase exhibits much of the Al-Si ordering present in the starting zeolite. These findings are considered in the context of perfect glasses predicted to occur when super strong liquids are supercooled

Direct investigations on strain-induced cold crystallization behavior and structure evolutions in amorphous poly(lactic acid) with SAXS and WAXS measurements

DEFF Research Database (Denmark)

Zhou, Chengbo; Li, Hongfei; Zhang, Wenyang

2016-01-01

scanning calorimetry (DSC) measurements. The data obtained from the stretched samples within 70-90 degrees C showed that all of the formed crystals are disordered alpha' form with more compact chain packing than that of the cold crystallization. Upon stretching at 70 degrees C, the mesocrystal appears......Strain-induced cold crystallization behavior and structure evolution of amorphous poly(lactic acid) (PLA) stretched within 70-90 degrees C were investigated via in situ synchrotron small-angle X-ray scattering (SAXS) and wide-angle X-ray scattering (WAXS) measurements as well as differential...... in strain-induced crystallization behavior of amorphous PLA within 70-90 degrees C can be attributed to the competition between chain orientation caused by stretching and chain relaxation. It was proposed that the strain-induced mesocrystal/crystal and the lamellae are formed from the mesophase originally...

PIXE and cSAXS studies at the bone-cartilage interface

International Nuclear Information System (INIS)

Kaabar, W.; Gundogdu, O.; Bradley, D.A.; Bunk, O.; Pfeiffer, F.; Farquharson, M.J.; Webb, M.; Jeynes, C.

2008-01-01

Full text: Divalent cations such as Zn and Ca play a central role both in the normal processes of growth and remodelling as well as in the degenerative and inflammatory processes of articular cartilage during arthritis. These cations act as co-factors of a class of enzymes known as metalloproteinases, believed to be active during the initiation, progress and remodelling processes associated with osteoarthritis. Other important enzymes such as alkaline phosphatase, involved in cartilage mineralization, are also associated with the presence of these metallic co-factors. A number of authors have used X-ray fluorescence, employing synchrotron radiation sources to map metal ion distributions in bone and cartilage. In the present work, investigations were carried out on the distribution of metallic ions (Zn, Ca, P and S) in articular cartilage samples at the University of Surrey hosted EPSRC national ion beam facility based on a 2 MV Tandetron accelerator. An in-air beam line was used, with proton energy of 2.5 MeV. Micro Proton-Induced X-ray Emission (μ-PIXE) analysis has been made of the bone-cartilage interface for samples taken from the human femoral head. The bone-cartilage interface region between uncalcified and mineralized cartilage regions has attracted particular interest, being identified to be an active site of remodelling. Here coherent small angle X-ray scattering (cSAXS) has also been employed to investigate the structure and organization of the collagen network in decalcified diseased human femoral heads and the equine metacarpus joint, study being carried out at the Paul Scherrer Institute (PSI) synchrotron beamline cSAXS. (Fig. 1: cSAXS over a 1 mm x 1.5 mm area of a cartilage/bone sample; the left- and right hand panels corresponds to the length scales 658-568 A and 962-833 A respectively. The bar scale indicates relative orientation, from 0 deg (blue) to 90 deg (red)). The results of Fig. 1 are plotted in terms of orientation of cartilage and bone

Modeling small angle scattering data using FISH

International Nuclear Information System (INIS)

Elliott, T.; Buckely, C.E.

2002-01-01

Full text: Small angle neutron scattering (SANS) and small angle x-ray scattering (SAXS) are important techniques for the characterisation of samples on the nanometer scale. From the scattered intensity pattern information about the sample such as particle size distribution, concentration and particle interaction can be determined. Since the experimental data is in reciprocal space and information is needed about real space, modeling of the scattering data to obtain parameters is extremely important and several paradigms are available. The use of computer programs to analyze the data is imperative for a robust description of the sample to be obtained. This presentation gives an overview of the SAS process and describes the data-modeling program FISH, written by R. Heenan 1983-2000. The results of using FISH to obtain the particle size distribution of bubbles in the aluminum hydrogen system and other systems of interest are described. Copyright (2002) Australian X-ray Analytical Association Inc

Structural Data on the Periplasmic Aldehyde Oxidoreductase PaoABC from Escherichia coli: SAXS and Preliminary X-ray Crystallography Analysis

Directory of Open Access Journals (Sweden)

Ana Rita Otrelo-Cardoso

2014-01-01

Full Text Available The periplasmic aldehyde oxidoreductase PaoABC from Escherichia coli is a molybdenum enzyme involved in detoxification of aldehydes in the cell. It is an example of an αβγ heterotrimeric enzyme of the xanthine oxidase family of enzymes which does not dimerize via its molybdenum cofactor binding domain. In order to structurally characterize PaoABC, X-ray crystallography and small angle X-ray scattering (SAXS have been carried out. The protein crystallizes in the presence of 20% (w/v polyethylene glycol 3350 using the hanging-drop vapour diffusion method. Although crystals were initially twinned, several experiments were done to overcome twinning and lowering the crystallization temperature (293 K to 277 K was the solution to the problem. The non-twinned crystals used to solve the structure diffract X-rays to beyond 1.80 Å and belong to the C2 space group, with cell parameters a = 109.42 Å, b = 78.08 Å, c = 151.77 Å, β = 99.77°, and one molecule in the asymmetric unit. A molecular replacement solution was found for each subunit separately, using several proteins as search models. SAXS data of PaoABC were also collected showing that, in solution, the protein is also an αβγ heterotrimer.

Reggeon effects in a geometrical model of elastic scattering. [Crossover curves, dip depth, scattering amplitude, 10 to 10,000 GeV

Energy Technology Data Exchange (ETDEWEB)

Dias de Deus, J [Instituto de Fisica e Matematica, Lisboa (Portugal); Kroll, P [Wuppertal Univ. (Gesamthochschule) (Germany, F.R.)

1976-08-21

The inclusion of secondary contributions Reggeons and real parts by changing the radial scale but exactly preserving geometrical scaling (GS) alloys an exclusion of GS to lower energies. The crossover curves in proton proton, Kp, and *pp are in this way correctly described. A GS formula relating two measurable quantities, the depth of the dip in proton proton scattering and the ratio of the real to immaginary part of the amplitude at t=0, is shown to be valid in the 10-1000 GeV region.

Determination of Size Distributions in Nanocrystalline Powders by TEM, XRD and SAXS

DEFF Research Database (Denmark)

Jensen, Henrik; Pedersen, Jørgen Houe; Jørgensen, Jens Erik

2006-01-01

Crystallite size distributions and particle size distributions were determined by TEM, XRD, and SAXS for three commercially available TiO2 samples and one homemade. The theoretical Guinier Model was fitted to the experimental data and compared to analytical expressions. Modeling of the XRD spectra...... the size distribution obtained from the XRD experiments; however, a good agreement was obtained between the two techniques. Electron microscopy, SEM and TEM, confirmed the primary particle sizes, the size distributions, and the shapes obtained by XRD and SAXS. The SSEC78 powder and the commercially...

The hidden X-ray breaks in afterglow light curves

International Nuclear Information System (INIS)

Curran, P. A.; Wijers, R. A. M. J.; Horst, A. J. van der; Starling, R. L. C.

2008-01-01

Gamma-Ray Burst (GRB) afterglow observations in the Swift era have a perceived lack of achromatic jet breaks compared to the BeppoSAX, or pre-Swift era. Specifically, relatively few breaks, consistent with jet breaks, are observed in the X-ray light curves of these bursts. If these breaks are truly missing, it has serious consequences for the interpretation of GRB jet collimation and energy requirements, and the use of GRBs as standard candles.Here we address the issue of X-ray breaks which are possibly 'hidden' and hence the light curves are misinterpreted as being single power-laws. We show how a number of precedents, including GRB 990510 and GRB 060206, exist for such hidden breaks and how, even with the well sampled light curves of the Swift era, these breaks may be left misidentified. We do so by synthesising X-ray light curves and finding general trends via Monte Carlo analysis. Furthermore, in light of these simulations, we discuss how to best identify achromatic breaks in afterglow light curves via multi-wavelength analysis

Formation process of hierarchical structures in crystalline polymers as analyzed by simultaneous measurements of small-angle X-ray scattering and other techniques

International Nuclear Information System (INIS)

Yamamoto, Katsuhiro; Sakurai, Shinichi

2006-01-01

Crystalline polymers spontaneously form hierarchical structures, which provide us a potential use as a specialty material. Recently, not only a crystalline homopolymer but also semi-crystalline block copolymers and crystalline polymer blends have been attracting interests for the study of a hierarchical structure. In order to analyze such hierarchical structures in a variety of length scales, a simultaneous measurement of small-(SAXS) and wide-angle (WAXS) X-ray scattering with differential scanning calorimetry (DSC), or with small-angle light scattering (Hv-SALS) are most suitable. In this review, we show some examples of the simultaneous measurements. With DSC, exothermic heat flow can be simultaneously measured with X-ray scattering. On the other hand, with Hv-SALS it is possible to analyze evolution of a spherulitic structure, which is the structure at the highest rank in the hierarchy. For both cases, one can realize that it is impossible to obtain good statistics for SAXS and WAXS measurements without synchrotron radiations. (author)

Studying nanostructure gradients in injection-molded polypropylene/montmorillonite composites by microbeam small-angle x-ray scattering

DEFF Research Database (Denmark)

Stribeck, Norbert; Schneider, Konrad; Zeinolebadi, Ahmad

2014-01-01

The core–shell structure in oriented cylindrical rods of polypropylene (PP) and nanoclay composites (NCs) from PP and montmorillonite (MMT) is studied by microbeam small-angle x-ray scattering (SAXS). The structure of neat PP is almost homogeneous across the rod showing regular semicrystalline......-shaped phyllosilicate filler particles....

Synchrotron SAXS Studies of Nanostructured Materials and Colloidal Solutions: A Review

Directory of Open Access Journals (Sweden)

Craievich A.F.

2002-01-01

Full Text Available Structural characterisations using the SAXS technique in a number of nanoheterogeneous materials and liquid solutions are reviewed. The studied systems are protein (lysozyme/water solutions, colloidal ZnO particles/water sols, nanoporous NiO-based xerogels, hybrid organic-inorganic siloxane-PEG and PPG nanocomposites and PbTe semiconductor nanocrystals embedded in a glass matrix. These investigations also focus on the transformations of time-varying structures and on structural changes related to variations in temperature and composition. The reviewed investigations aim at explaining the unusual and often interesting properties of nanostructured materials and solutions. Most of the reported studies were carried out using the SAXS beamline at the National Synchrotron Light Laboratory (LNLS, Campinas, Brazil.

Laser ablation and injection moulding as techniques for producing micro channels compatible with Small Angle X-Ray Scattering

DEFF Research Database (Denmark)

Haider, R.; Marmiroli, B.; Gavalas, I.

2018-01-01

Microfluidic mixing is an important means for in-situ sample preparation and handling while Small Angle X-Ray Scattering (SAXS) is a proven tool for characterising (macro-)molecular structures. In combination those two techniques enable investigations of fast reactions with high time resolution......, the requirement for low scattering especially limits the techniques suitable for producing the mixer, as the fabrication process can induce molecular orientations and stresses that can adversely influence the scattering signal. Not only is it important to find a production method that results in a device with low...

Scanning of Adsorption Hysteresis In Situ with Small Angle X-Ray Scattering.

Directory of Open Access Journals (Sweden)

Athanasios Ch Mitropoulos

Full Text Available Everett's theorem-6 of the domain theory was examined by conducting adsorption in situ with small angle x-ray scattering (SAXS supplemented by the contrast matching technique. The study focuses on the spectrum differences of a point to which the system arrives from different scanning paths. It is noted that according to this theorem at a common point the system has similar macroscopic properties. Furthermore it was examined the memory string of the system. We concluded that opposite to theorem-6: a at a common point the system can reach in a finite (not an infinite number of ways, b a correction for the thickness of the adsorbed film prior to capillary condensation is necessary, and c the scattering curves although at high-Q values coincide, at low-Q values are different indicating different microscopic states. That is, at a common point the system holds different metastable states sustained by hysteresis effects. These metastable states are the ones which highlight the way of a system back to a return point memory (RPM. Entering the hysteresis loop from different RPMs different histories are implanted to the paths toward the common point. Although in general the memory points refer to relaxation phenomena, they also constitute a characteristic feature of capillary condensation. Analogies of the no-passing rule and the adiabaticity assumption in the frame of adsorption hysteresis are discussed.

Scanning of Adsorption Hysteresis In Situ with Small Angle X-Ray Scattering

Science.gov (United States)

Mitropoulos, Athanasios Ch.; Favvas, Evangelos P.; Stefanopoulos, Konstantinos L.; Vansant, Etienne F.

2016-01-01

Everett’s theorem-6 of the domain theory was examined by conducting adsorption in situ with small angle x-ray scattering (SAXS) supplemented by the contrast matching technique. The study focuses on the spectrum differences of a point to which the system arrives from different scanning paths. It is noted that according to this theorem at a common point the system has similar macroscopic properties. Furthermore it was examined the memory string of the system. We concluded that opposite to theorem-6: a) at a common point the system can reach in a finite (not an infinite) number of ways, b) a correction for the thickness of the adsorbed film prior to capillary condensation is necessary, and c) the scattering curves although at high-Q values coincide, at low-Q values are different indicating different microscopic states. That is, at a common point the system holds different metastable states sustained by hysteresis effects. These metastable states are the ones which highlight the way of a system back to a return point memory (RPM). Entering the hysteresis loop from different RPMs different histories are implanted to the paths toward the common point. Although in general the memory points refer to relaxation phenomena, they also constitute a characteristic feature of capillary condensation. Analogies of the no-passing rule and the adiabaticity assumption in the frame of adsorption hysteresis are discussed. PMID:27741263

Calculation of X-ray scattering curves and electron distance distribution functions of biological macromolecules in solution using the PROTEIN DATA BANK

International Nuclear Information System (INIS)

Mueller, J.J.; Friedrichowicz, E.; Nothnagel, A.; Wunderlich, T.; Ziehlsdorf, E.; Damaschun, G.

1983-01-01

The wide angle X-ray scattering curve, the electron distance distribution function and the solvent excluded volume of a macromolecule in solution are calculated from the atomic coordinates contained in the PROTEIN DATA BANK. The structures and the projections of the excluded volumes are depicted using molecule graphic routines. The described computer programs are used to determine the three-dimensional structure of macromolecules in solution from wide angle X-ray scattering data. (author)

Synchrotron SAXS studies of nanostructured materials and colloidal solutions: a review

International Nuclear Information System (INIS)

Craievich, A.F.

2002-01-01

Structural characterisations using the SAXS technique in a number of nano heterogeneous materials and liquid solutions are reviewed. The studied systems are protein (lysozyme)/water solutions, colloidal Zn O particles/water sols, nano porous Ni O-based xerogels, hybrid organic-inorganic siloxane-PEG and PPG nano composites and PbTe semiconductor nano crystals embedded in a glass matrix. These investigations also focus on the transformations of time-varying structures and on structural changes related to variations in temperature and composition. The reviewed investigations aim at explaining the unusual and often interesting properties of nano structured materials and solutions. Most of the reported studies were carried out using the SAXS beamline at the National Synchrotron Light Laboratory (LNLS), Campinas, Brazil.(author)

Transformation from Multilamellar to Unilamellar Vesicles by Addition of a Cationic Lipid to PEGylated Liposomes Explored with Synchrotron Small Angle X-ray Scattering

International Nuclear Information System (INIS)

Sakuragi, Mina; Sakurai, Kazuo; Koiwai, Kazunori; Nakamura, Kouji; Masunaga, Hiroyasu; Ogawa, Hiroki

2011-01-01

PEGylated liposomes composed of a benzamidine derivative (TRX), hydrogenated soybean phosphatidylcholine (HSPC), and N-(monomethoxy-polyethyleneglycolcarbamyl) distearoyl phosphatidylethanolamine (PEG-PE) were examined in terms of how the addition of TRX affects their structures with small angle x-ray scattering (SAXS) as well as transmission electron microscopy (TEM). TEM images showed the presence of unilamella vesicles for both with and without TRX, though a small amount of multilamella vesicles were observed in absence of TRX. We analyzed SAXS profiles at contained TRX composition combined with contrast variation technique by adding PEG solution and unilamella vesicle model could be reproduced. Subsequently, we analyzed SAXS profiles at no TRX composition. The mixture model of unilamella and multilamella vesicle was reconstructed and we estimated about 10 % multilamella vesicles from a fitting parameter.

Understanding nucleic acid structural changes by comparing wide-angle x-ray scattering (WAXS) experiments to molecular dynamics simulations

Energy Technology Data Exchange (ETDEWEB)

Pabit, Suzette A.; Katz, Andrea M.; Pollack, Lois [School of Applied and Engineering Physics, Cornell University, Ithaca, New York 14853 (United States); Tolokh, Igor S. [Department of Computer Science, Virginia Tech, Blacksburg, Virginia 24061 (United States); Drozdetski, Aleksander [Department of Physics, Virginia Tech, Blacksburg, Virginia 24061 (United States); Baker, Nathan [Pacific Northwest National Laboratory, Richland, Washington 99352 (United States); Onufriev, Alexey V. [Department of Computer Science, Virginia Tech, Blacksburg, Virginia 24061 (United States); Department of Physics, Virginia Tech, Blacksburg, Virginia 24061 (United States)

2016-05-28

Wide-angle x-ray scattering (WAXS) is emerging as a powerful tool for increasing the resolution of solution structure measurements of biomolecules. Compared to its better known complement, small angle x-ray scattering (SAXS), WAXS targets higher scattering angles and can enhance structural studies of molecules by accessing finer details of solution structures. Although the extension from SAXS to WAXS is easy to implement experimentally, the computational tools required to fully harness the power of WAXS are still under development. Currently, WAXS is employed to study structural changes and ligand binding in proteins; however, the methods are not as fully developed for nucleic acids. Here, we show how WAXS can qualitatively characterize nucleic acid structures as well as the small but significant structural changes driven by the addition of multivalent ions. We show the potential of WAXS to test all-atom molecular dynamics (MD) simulations and to provide insight into understanding how the trivalent ion cobalt(III) hexammine (CoHex) affects the structure of RNA and DNA helices. We find that MD simulations capture the RNA structural change that occurs due to addition of CoHex.

SAXS study of sterically stabilized lipid nanocarriers functionalized by DNA

Czech Academy of Sciences Publication Activity Database

Angelov, Borislav; Angelova, A.; Filippov, Sergey K.; Karlsson, G.; Terrill, N.; Lesieur, S.; Štěpánek, Petr

2012-01-01

Roč. 351, č. 1 (2012), s. 012004 ISSN 1742-6588. [SANS-YuMO User Meeting. Dubna, 27.05.2011-30.05.2011] Institutional research plan: CEZ:AV0Z40500505 Keywords : SAXS * vesicles * self-assembly Subject RIV: CD - Macromolecular Chemistry

An Assessment of Critical Dimension Small Angle X-ray Scattering Metrology for Advanced Semiconductor Manufacturing

Energy Technology Data Exchange (ETDEWEB)

Settens, Charles M. [State Univ. of New York (SUNY), Albany, NY (United States)

2015-01-01

Simultaneous migration of planar transistors to FinFET architectures, the introduction of a plurality of materials to ensure suitable electrical characteristics, and the establishment of reliable multiple patterning lithography schemes to pattern sub-10 nm feature sizes imposes formidable challenges to current in-line dimensional metrologies. Because the shape of a FinFET channel cross-section immediately influences the electrical characteristics, the evaluation of 3D device structures requires measurement of parameters beyond traditional critical dimension (CD), including their sidewall angles, top corner rounding and footing, roughness, recesses and undercuts at single nanometer dimensions; thus, metrologies require sub-nm and approaching atomic level measurement uncertainty. Synchrotron critical dimension small angle X-ray scattering (CD-SAXS) has unique capabilities to non-destructively monitor the cross-section shape of surface structures with single nanometer uncertainty and can perform overlay metrology to sub-nm uncertainty. In this dissertation, we perform a systematic experimental investigation using CD-SAXS metrology on a hierarchy of semiconductor 3D device architectures including, high-aspect-ratio contact holes, H2 annealed Si fins, and a series of grating type samples at multiple points along a FinFET fabrication process increasing in structural intricacy and ending with fully fabricated FinFET. Comparative studies between CD-SAXS metrology and other relevant semiconductor dimensional metrologies, particularly CDSEM, CD-AFM and TEM are used to determine physical limits of CD-SAXS approach for advanced semiconductor samples. CD-SAXS experimental tradeoffs, advice for model-dependent analysis and thoughts on the compatibility with a semiconductor manufacturing environment are discussed.

Preliminary small-angle X-ray scattering and X-ray diffraction studies of the BTB domain of lola protein from Drosophila melanogaster

Science.gov (United States)

Boyko, K. M.; Nikolaeva, A. Yu.; Kachalova, G. S.; Bonchuk, A. N.; Dorovatovskii, P. V.; Popov, V. O.

2017-11-01

The Drosophila genome has several dozens of transcription factors (TTK group) containing BTB domains assembled into octamers. The LOLA protein belongs to this family. The purification, crystallization, and preliminary X-ray diffraction and small-angle X-ray scattering (SAXS) studies of the BTB domain of this protein are reported. The crystallization conditions were found by the vapor-diffusion technique. A very low diffraction resolution (8.7 Å resolution) of the crystals was insufficient for the determination of the threedimensional structure of the BTB domain. The SAXS study demonstrated that the BTB domain of the LOLA protein exists as an octamer in solution.

Measuring the molecular dimensions of wine tannins: comparison of small-angle X-ray scattering, gel-permeation chromatography and mean degree of polymerization.

Science.gov (United States)

McRae, Jacqui M; Kirby, Nigel; Mertens, Haydyn D T; Kassara, Stella; Smith, Paul A

2014-07-23

The molecular size of wine tannins can influence astringency, and yet it has been unclear as to whether the standard methods for determining average tannin molecular weight (MW), including gel-permeation chromatography (GPC) and depolymerization reactions, are actually related to the size of the tannin in wine-like conditions. Small-angle X-ray scattering (SAXS) was therefore used to determine the molecular sizes and corresponding MWs of wine tannin samples from 3 and 7 year old Cabernet Sauvignon wine in a variety of wine-like matrixes: 5-15% and 100% ethanol; 0-200 mM NaCl and pH 3.0-4.0, and compared to those measured using the standard methods. The SAXS results indicated that the tannin samples from the older wine were larger than those of the younger wine and that wine composition did not greatly impact on tannin molecular size. The average tannin MWs as determined by GPC correlated strongly with the SAXS results, suggesting that this method does give a good indication of tannin molecular size in wine-like conditions. The MW as determined from the depolymerization reactions did not correlate as strongly with the SAXS results. To our knowledge, SAXS measurements have not previously been attempted for wine tannins.

SAXS Studies of TiO2 Nanoparticles in Polymer Electrolytes and in Nanostructured Films

Directory of Open Access Journals (Sweden)

Sigrid Bernstorff

2010-11-01

Full Text Available Polymer electrolytes as nanostructured materials are very attractive components for batteries and opto-electronic devices. (PEO8ZnCl2 polymer electrolytes were prepared from PEO and ZnCl2. The nanocomposites (PEO8ZnCl2/TiO2 themselves contained TiO2 nanograins. In this work, the influence of the TiO2 nanograins on the morphology and ionic conductivity of the nanocomposite was systematically studied by transmission small-angle X-ray scattering (SAXS simultaneously recorded with wide-angle X-ray diffraction (WAXD and differential scanning calorimetry (DSC at the synchrotron ELETTRA. Films containing nanosized grains of titanium dioxide (TiO2 are widely used in the research of optical and photovoltaic devices. The TiO2 films, prepared by chemical vapor deposition and e-beam epitaxy, were annealed in hydrogen atmospheres in the temperature range between 20 °C and 900 °C in order to study anatase-rutile phase transition at 740 °C. Also, grazing-incidence small angle X-ray scattering (GISAXS spectra for each TiO2 film were measured in reflection geometry at different grazing incident angles. Environmentally friendly galvanic cells, as well as solar cells of the second generation, are to be constructed with TiO2 film as working electrode, and nanocomposite polymer as electrolyte.

Solution small-angle x-ray scattering as a screening and predictive tool in the fabrication of asymmetric block copolymer membranes

KAUST Repository

Dorin, Rachel Mika; Marques, Debora S.; Sai, Hiroaki; Vainio, Ulla; Phillip, William A.; Peinemann, Klaus; Nunes, Suzana Pereira; Wiesner, Ulrich B.

2012-01-01

Small-angle X-ray scattering (SAXS) analysis of the diblock copolymer poly(styrene-b-(4-vinyl)pyridine) in a ternary solvent system of 1,4-dioxane, tetrahydrofuran, and N,N-dimethylformamide, and the triblock terpolymer poly(isoprene-b-styrene-b-(4-vinyl)-pyridine) in a binary solvent system of 1,4-dioxane and tetrahydrofuran, reveals a concentration-dependent onset of ordered structure formation. Asymmetric membranes fabricated from casting solutions with polymer concentrations at or slightly below this ordering concentration possess selective layers with the desired nanostructure. In addition to rapidly screening possible polymer solution concentrations, solution SAXS analysis also predicts hexagonal and square pore lattices of the final membrane surface structure. These results suggest solution SAXS as a powerful tool for screening casting solution concentrations and predicting surface structure in the fabrication of asymmetric ultrafiltration membranes from self-assembled block copolymers. (Figure presented) © 2012 American Chemical Society.

Solution small-angle x-ray scattering as a screening and predictive tool in the fabrication of asymmetric block copolymer membranes

KAUST Repository

Dorin, Rachel Mika

2012-05-15

Small-angle X-ray scattering (SAXS) analysis of the diblock copolymer poly(styrene-b-(4-vinyl)pyridine) in a ternary solvent system of 1,4-dioxane, tetrahydrofuran, and N,N-dimethylformamide, and the triblock terpolymer poly(isoprene-b-styrene-b-(4-vinyl)-pyridine) in a binary solvent system of 1,4-dioxane and tetrahydrofuran, reveals a concentration-dependent onset of ordered structure formation. Asymmetric membranes fabricated from casting solutions with polymer concentrations at or slightly below this ordering concentration possess selective layers with the desired nanostructure. In addition to rapidly screening possible polymer solution concentrations, solution SAXS analysis also predicts hexagonal and square pore lattices of the final membrane surface structure. These results suggest solution SAXS as a powerful tool for screening casting solution concentrations and predicting surface structure in the fabrication of asymmetric ultrafiltration membranes from self-assembled block copolymers. (Figure presented) © 2012 American Chemical Society.

Evolution and change of He bubbles in He-containing Ti films upon thermal treatment studied by small-angle X-ray scattering and transmission electron microscopy

Energy Technology Data Exchange (ETDEWEB)

Sun, Guangai [Institute of Nuclear Physics and Chemistry, China Academy of Engineering Physics, Mianyang 621900 (China); College of Nuclear Science and Technology, University of Science and Technology of China, Hefei, 230029 (China); Wu, Erdong, E-mail: ewu@imr.ac.cn [National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016 (China); Huang, Chaoqiang [Institute of Nuclear Physics and Chemistry, China Academy of Engineering Physics, Mianyang 621900 (China); College of Nuclear Science and Technology, University of Science and Technology of China, Hefei, 230029 (China); Cheng, Chun [National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016 (China); Yan, Guanyun [Institute of Nuclear Physics and Chemistry, China Academy of Engineering Physics, Mianyang 621900 (China); Wang, Xiaolin [Institute of Nuclear Physics and Chemistry, China Academy of Engineering Physics, Mianyang 621900 (China); College of Nuclear Science and Technology, University of Science and Technology of China, Hefei, 230029 (China); Liu, Shi [National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016 (China); Tian, Qiang; Chen, Bo [Institute of Nuclear Physics and Chemistry, China Academy of Engineering Physics, Mianyang 621900 (China); Wu, Zhonghua [Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049 (China); Liu, Yi; Wang, Jie [Institute of Shanghai Apply Physics, Chinese Academy of Sciences, Shanghai 201800 (China)

2014-05-02

Evolution and change of He bubbles in magnetron sputtering prepared He-containing Ti films under thermal treatment are studied by small-angle X-ray scattering (SAXS), transmission electron microscopy (TEM) and X-ray diffraction. Incorporation of He introduces a large number of He-vacancy clusters and some voids in the films, and significantly increases SAXS intensity and causes anisotropic scattering. The change of He induced defects during annealing is affected by thermal diffusion and migration of trapped He to the surface and between interfaces of He induced defects within the films. Annealing at 200 and 400 °C reduces intensity and anisotropy of SAXS, in accord with observed shrinking and disappearance of the voids. The simultaneous growth of non-uniformly distributed He bubbles to the sizes of 1–2 nm and a population level of 10{sup 5}/μm{sup 3} are detected in the temperature range. The changes are explained by migration and coalescence mechanisms, which requires low apparent activation energy. Inconsistence between TEM and SAXS observations is noted and attributed to thinning induced internal stress relaxation of TEM specimen. Remarkable enlargement of He bubbles, associated with increased SAXS intensity and fractal dimension, is observed after 600 °C annealing, indicating involvement of Ostwald Ripening (OR) mechanism. The OR process dominates at 800 °C, where the high temperature provides activation energy for accelerated He dissociation from small bubbles into larger ones, and generating textured microstructure and agglomerated bubble clusters. The inhomogeneous bubble size distribution observed at this temperature covers a broad range of about 10–50 nm and possessing a population density level of 10{sup 3}/μm{sup 3}. - Highlights: • Change of He bubbles in thermally treated Ti–He films is studied by SAXS and TEM. • SAXS reveals size distribution and fractional population of He bubbles in films. • He-vacancy clusters in Ti–He film

Total Reflection X-ray Fluorescence Analysis (TXRF) using the high flux SAXS camera

CERN Document Server

Wobrauschek, P; Pepponi, G; Bergmann, A; Glatter, O

2002-01-01

Combining the high photon flux from a rotating anode X-ray tube with an X-ray optical component to focus and monochromatize the X-ray beam is the most promising instrumentation for best detection limits in the modern XRF laboratory. This is realized by using the design of a high flux SAXS camera in combination with a 4 kW high brilliant rotating Cu anode X-ray tube with a graded elliptically bent multilayer and including a new designed module for excitation in total reflection geometry within the beam path. The system can be evacuated thus reducing absorption and scattering of air and removing the argon peak in the spectra. Another novelty is the use of a Peltier cooled drift detector with an energy resolution of 148 eV at 5.9 keV and 5 mm sup 2 area. For Co detection limits of about 300 fg determined by a single element standard have been achieved. Testing a real sample NIST 1643d led to detection limits in the range of 300 ng/l for the medium Z.

The Peculiar Light Curve of J1415+1320: A Case Study in Extreme Scattering Events

Science.gov (United States)

Vedantham, H. K.; Readhead, A. C. S.; Hovatta, T.; Koopmans, L. V. E.; Pearson, T. J.; Blandford, R. D.; Gurwell, M. A.; Lähteenmäki, A.; Max-Moerbeck, W.; Pavlidou, V.; Ravi, V.; Reeves, R. A.; Richards, J. L.; Tornikoski, M.; Zensus, J. A.

2017-08-01

The radio light curve of J1415+1320 (PKS 1413+135) shows time-symmetric and recurring U-shaped features across the centimeter-wave and millimeter-wave bands. The symmetry of these features points to lensing by an intervening object as the cause. U-shaped events in radio light curves in the centimeter-wave band have previously been attributed to Extreme scattering events (ESE). ESEs are thought to be the result of lensing by compact plasma structures in the Galactic interstellar medium, but the precise nature of these plasma structures remains unknown. Since the strength of a plasma lens evolves with wavelength λ as {λ }2, the presence of correlated variations at over a wide wavelength range casts doubt on the canonical ESE interpretation for J1415+1320. In this paper, we critically examine the evidence for plasma lensing in J1415+1320. We compute limits on the lensing strength and the associated free-free opacity of the putative plasma lenses. We compare the observed and model ESE light curves, and also derive a lower limit on the lens distance based on the effects of parallax due to the Earth’s orbit around the Sun. We conclude that plasma lensing is not a viable interpretation for J1415+1320's light curves and that symmetric U-shaped features in the radio light curves of extragalactic sources do not present prima facie evidence for ESEs. The methodology presented here is generic enough to be applicable to any plasma-lensing candidate.

A modulated differential scanning calorimetry and small-angle x-ray scattering study of the interfacial region in structured latices

Directory of Open Access Journals (Sweden)

Hourston Douglas J.

2001-01-01

Full Text Available The interfacial structure of poly(styrene (PS-poly(methyl acrylate (PMA structured latices has been investigated by means of modulated-temperature differential scanning calorimetry (M-TDSC and small-angle x-ray scattering (SAXS. The differential of heat capacity, dCp/dT, signal from M-TDSC was used to quantify the weight fraction of interface in these latices. For PS-PMA (50:50 by weight structured latices in which the PS component had different crosslink densities (0, 1, 3, 5 and 10 mol% of crosslinking agent, the weight fraction of interface was about 13%. With increasing crosslink density, the fraction of interface increased only slightly. A core-shell model has been used to analyse SAXS data for these PS-PMA latices. M-TDSC can only provide information about the weight fraction of interface, but the combination of M-TDSC and SAXS can provide much more information on the morphology of such structured latices.

Quantitative analysis and relevant features of the scientific literature related to SAXS and SANS

International Nuclear Information System (INIS)

Craievich, Aldo F; Fischer, Hannes

2010-01-01

We present and discuss here numerical information derived from a systematic searching of scientific papers related to SAXS and SANS published in indexed journals - from 1945 until nowadays - recorded by the Web of Science Data Bank (WoS). We have detected interesting features regarding the time dependence of the number of papers/year, N(t), indicating the existence of three well-defined periods of historical evolution with rather well-defined boundaries. All three periods exhibit a positive and approximately linear variation of N(t) but, at the two transitions between periods, the rate of growth exhibits clear and strong increases. Differences of the historical evolutions in the numbers of papers/year related to SAXS and to SANS were established. The different behaviours regarding the numbers of papers/year related to SAXS and to SANS and the existence of three different and well defined periods for N(t) can be qualitatively understood as a consequence of the progressive and increasing availability along the last three decades of very brilliant synchrotrons, last generation commercial X-ray sources, new neutron facilities, powerful computers and novel theoretical approaches for SAS data analysis. The rates of growth in the number of papers/year published by authors from a set of different countries are approximately constant along the last two decades. For other countries we have detected a slowing down effect in the number of papers/year while a clear acceleration could be noticed for the production of SAS papers by authors from several emerging countries. These opposite trends compensate in such a way that the number of SAS (SAXS+SAXS) articles published per year all around the world maintained a vigorous linear growth - during more than 20 years - at a constant rate of 60 papers/year, without any indication of eventual saturation. The observed distribution of articles among different journals indicates that a very high fraction of the volume of SAS research is

Healing X-ray scattering images

Directory of Open Access Journals (Sweden)

Jiliang Liu

2017-07-01

Full Text Available X-ray scattering images contain numerous gaps and defects arising from detector limitations and experimental configuration. We present a method to heal X-ray scattering images, filling gaps in the data and removing defects in a physically meaningful manner. Unlike generic inpainting methods, this method is closely tuned to the expected structure of reciprocal-space data. In particular, we exploit statistical tests and symmetry analysis to identify the structure of an image; we then copy, average and interpolate measured data into gaps in a way that respects the identified structure and symmetry. Importantly, the underlying analysis methods provide useful characterization of structures present in the image, including the identification of diffuse versus sharp features, anisotropy and symmetry. The presented method leverages known characteristics of reciprocal space, enabling physically reasonable reconstruction even with large image gaps. The method will correspondingly fail for images that violate these underlying assumptions. The method assumes point symmetry and is thus applicable to small-angle X-ray scattering (SAXS data, but only to a subset of wide-angle data. Our method succeeds in filling gaps and healing defects in experimental images, including extending data beyond the original detector borders.

Beyond simple small-angle X-ray scattering: developments in online complementary techniques and sample environments.

Science.gov (United States)

Bras, Wim; Koizumi, Satoshi; Terrill, Nicholas J

2014-11-01

Small- and wide-angle X-ray scattering (SAXS, WAXS) are standard tools in materials research. The simultaneous measurement of SAXS and WAXS data in time-resolved studies has gained popularity due to the complementary information obtained. Furthermore, the combination of these data with non X-ray based techniques, via either simultaneous or independent measurements, has advanced understanding of the driving forces that lead to the structures and morphologies of materials, which in turn give rise to their properties. The simultaneous measurement of different data regimes and types, using either X-rays or neutrons, and the desire to control parameters that initiate and control structural changes have led to greater demands on sample environments. Examples of developments in technique combinations and sample environment design are discussed, together with a brief speculation about promising future developments.

X-ray small-angle scattering of polytetrahydrofuran solution, 3

International Nuclear Information System (INIS)

Izumi, Yoshinobu; Fuji, Masayuki; Shinbo, Kazuyuki; Miyake, Yasuhiro

1975-01-01

In a previous report, the conformation of polytetrahydrofuran (PTHF) in isopropyl alcohol as a theta solvent and in n-butyl alcohol as an intermediate solvent was examined by the small angle scattering of X-ray. As the result, the experimental scattering curve at theta temperature was explained well with the calculated curve obtained by superposing, while it was impossible to apply the similar method to the analysis of the scattering curve in the intermediate solvent. Recently, as the results of the calculation by Koyama on the angular distribution of light intensity scattered by stiff chain polymers and of the studies by Edwards and de Gennes on the asymptotic behavior of scattering curves in good solvents, the direct comparison of experimental and calculated scattering curves became possible. In this report, the comparison of the scattering curves of PTHF-alcohol systems is described. The systems employed were PTHF-n-propyl alcohol, PTHF-isobutyl alcohol, PTHF-sec-butyl alcohol, and PTHF-tert-butyl alcohol in addition to the previous two systems. The Guinier plots of the cross section factors of the PTHF-alcohol systems showed that the Guinier approximation on cross sections was not satisfied in cases of PTHF-isobutyl alcohol and PTHF-sec-butyl alcohol. The light scattering data at 44.6 0 C, the theta temperature of PTHF-isopropyl alcohol, are given. From the figures comparing experimental and calculated scattering curves, it was shown that there was appreciable solvent effect on the scattering curves of PTHF-alcohol systems. The relation predicted by Edwards and de Gennes was satisfied well in case of the systems in good solvents. (Kako, I.)

James Wertsi ja SaxEsti ühiskontsert. "Valge gospel" asub taas tuurile

Index Scriptorium Estoniae

2007-01-01

Ameerika laulja ja kitarristi James Wertsi ning saksofonikvarteti SaxEst kontserdituurist Eestis algusega 1. dets. Haljala rahvamajast. Kontserdituurist "Valge gospel" alates 11. dets. kuues Eestimaa kirikus (viimane kontsert 20. dets. Tallinna Linnahallis)

Prediction of protein structure with the coarse-grained UNRES force field assisted by small X-ray scattering data and knowledge-based information.

Science.gov (United States)

Karczyńska, Agnieszka S; Mozolewska, Magdalena A; Krupa, Paweł; Giełdoń, Artur; Liwo, Adam; Czaplewski, Cezary

2018-03-01

A new approach to assisted protein-structure prediction has been proposed, which is based on running multiplexed replica exchange molecular dynamics simulations with the coarse-grained UNRES force field with restraints derived from knowledge-based models and distance distribution from small angle X-ray scattering (SAXS) measurements. The latter restraints are incorporated into the target function as a maximum-likelihood term that guides the shape of the simulated structures towards that defined by SAXS. The approach was first verified with the 1KOY protein, for which the distance distribution was calculated from the experimental structure, and subsequently used to predict the structures of 11 data-assisted targets in the CASP12 experiment. Major improvement of the GDT_TS was obtained for 2 targets, minor improvement for other 2 while, for 6 target GDT_TS deteriorated compared with that calculated for predictions without the SAXS data, partly because of assuming a wrong multimeric state (for Ts866) or because the crystal conformation was more compact than the solution conformation (for Ts942). Particularly good results were obtained for Ts909, in which use of SAXS data resulted in the selection of a correctly packed trimer and, subsequently, increased the GDT_TS of monomer prediction. It was found that running simulations with correct oligomeric state is essential for the success in SAXS-data-assisted prediction. © 2017 Wiley Periodicals, Inc.

Time-resolved SAXS measurements facilitated by online HPLC buffer exchange

DEFF Research Database (Denmark)

Jensen, Malene Hillerup; Toft, Katrine Nørgaard; David, Gabriel

2010-01-01

continuous or stopped flow. In this paper a method for obtaining TR-SAXS data from systems where the reaction is triggered by removal of a species is presented. This method is based on fast buffer exchange over a short desalting column facilitated by an online HPLC (high-performance liquid chromatography...

Monoacyl phosphatidylcholine inhibits the formation of lipid multilamellar structures during in vitro lipolysis of self-emulsifying drug delivery systems.

Science.gov (United States)

Tran, Thuy; Siqueira, Scheyla D V S; Amenitsch, Heinz; Rades, Thomas; Müllertz, Anette

2017-10-15

The colloidal structures formed during lipolysis of self-emulsifying drug delivery systems (SEDDS) might affect the solubilisation and possibly the absorption of drugs. The aim of the current study is to elucidate the structures formed during the in vitro lipolysis of four SEDDS containing medium-chain glycerides and caprylocaproyl polyoxyl-8 glycerides (Labrasol), with or without monoacyl phosphatidylcholine (MAPC). In situ synchrotron small-angle X-ray scattering (SAXS) was combined with ex situ cryogenic transmission electron microscopy (cryo-TEM) and dynamic light scattering (DLS) to elucidate the generated structures. The SAXS scattering curves obtained during the lipolysis of MAPC-free SEDDS containing 43-60% w/w Labrasol displayed a lamellar phase peak at q=2.13nm -1 that increased with Labrasol concentration, suggesting the presence of multilamellar structures (MLS) with a d-spacing of 2.95nm. However, SEDDS containing 20-30% w/w MAPC did not form MLS during the lipolysis. The cryo-TEM and DLS studies showed that MAPC-free SEDDS formed coarse emulsions while MAPC-containing SEDDS formed nanoemulsions during the dispersion in digestion medium. From the first minute and during the entire lipolysis process, SEDDS both with and without MAPC generated uni-, bi-, and oligo-lamellar vesicles. The lipolysis kinetics in the first minutes of the four SEDDS correlated with an increased intensity of the SAXS curves and the rapid transformation from lipid droplets to vesicles observed by cryo-TEM. In conclusion, the study elucidates the structures formed during in vitro lipolysis of SEDDS and the inhibitory effect of MAPC on the formation of MLS. Copyright © 2016 Elsevier B.V. All rights reserved.

Structure of Nanoporous Biocarbon for Hydrogen Storage as Determined by Small Angle X-Ray Scattering

Science.gov (United States)

Wood, Mikael; Burress, J.; Pobst, J.; Carter, S.; Pfeifer, P.; Wexler, C.; Shah, P.; Suppes, G.

2008-03-01

As a member of the Alliance for Collaborative Research in Alternative Fuel Technology (ALL-CRAFT) our research group studies the properties of nanoporous biocarbon, produced from waste corn cob, with the goal of achieving the Department of Energy's gravimetric and volumetric standards for both hydrogen and methane gas storage. Small Angle X-Ray Scattering (SAXS) is a valuable tool in our investigation of the geometry of the pore space in our carbon samples. In this talk, we will compare the experimental SAXS data with theoretical results for various pore geometries to determine which pore models are consistent with experiment. Using data from nitrogen adsorption isotherms, along with SAXS, yields significant structural information about the pore space. This analysis should allow us to fully optimize our production process and to achieve the DOE's target storage capacities. This work supported by: 1. National Science Foundation (PFI-0438469) 2. U.S. Department of Education (P200A040038) 3. U.S. Department of Energy (DE-AC02-06CH11357) 4. University of Missouri (RB-06-040) 5. U.S. Department of Defense (N00164-07-P-1306) 6. U.S. Department of Energy (DE-FG02-07ER46411)

Combined in situ small and wide angle X-ray scattering studies of TiO2 nano-particle annealing to 1023 K

DEFF Research Database (Denmark)

Kehres, Jan; Andreasen, Jens Wenzel; Krebs, Frederik C

2010-01-01

Combined in situ small- and wide-angle X-ray scattering (SAXS/WAXS) studies were performed in a recently developed laboratory setup to investigate the dynamical properties of dry oleic acid-capped titanium dioxide nanorods during annealing in an inert gas stream in a temperature interval of 298-1...

Repeated sorption of water in SBA-15 investigated by means of in situ small-angle x-ray scattering

International Nuclear Information System (INIS)

Erko, M; Paris, O; Wallacher, D; Findenegg, G H

2012-01-01

The effect of repeated cycles of water adsorption/desorption on the structural stability of ordered mesoporous silica SBA-15 is studied by small-angle x-ray scattering (SAXS). In situ sorption measurements are conducted using a custom-built sorption apparatus in connection with a laboratory SAXS setup. Two striking irreversible changes are observed in the sorption isotherms as derived from the integrated SAXS intensity. First, the capillary condensation pressure shifts progressively to lower relative pressure values with increasing number of sorption cycles. This effect is attributed to chemisorption of water at the silica walls, resulting in a change of the fluid-wall interaction. Second, the sorption cycles do not close completely at vanishing vapour pressure, suggesting that progressively more water remains trapped within the porous material after each cycle. This effect is interpreted to be the result of an irreversible collapse of parts of mesopores, originating from pore wall deformation due to the large Laplace pressure of water acting on the pore walls at capillary condensation and capillary evaporation. (paper)

Roc curves for continuous data

CERN Document Server

Krzanowski, Wojtek J

2009-01-01

Since ROC curves have become ubiquitous in many application areas, the various advances have been scattered across disparate articles and texts. ROC Curves for Continuous Data is the first book solely devoted to the subject, bringing together all the relevant material to provide a clear understanding of how to analyze ROC curves.The fundamental theory of ROC curvesThe book first discusses the relationship between the ROC curve and numerous performance measures and then extends the theory into practice by describing how ROC curves are estimated. Further building on the theory, the authors prese

Beyond simple small-angle X-ray scattering: developments in online complementary techniques and sample environments

Directory of Open Access Journals (Sweden)

Wim Bras

2014-11-01

Full Text Available Small- and wide-angle X-ray scattering (SAXS, WAXS are standard tools in materials research. The simultaneous measurement of SAXS and WAXS data in time-resolved studies has gained popularity due to the complementary information obtained. Furthermore, the combination of these data with non X-ray based techniques, via either simultaneous or independent measurements, has advanced understanding of the driving forces that lead to the structures and morphologies of materials, which in turn give rise to their properties. The simultaneous measurement of different data regimes and types, using either X-rays or neutrons, and the desire to control parameters that initiate and control structural changes have led to greater demands on sample environments. Examples of developments in technique combinations and sample environment design are discussed, together with a brief speculation about promising future developments.

Scattering Studies of Hydrophobic Monomers in Liposomal Bilayers: An Expanding Shell Model of Monomer Distribution

International Nuclear Information System (INIS)

Richter, Andrew; Dergunov, Sergey; Ganus, Bill; Thomas, Zachary; Pingali, Sai Venkatesh; Urban, Volker S.; Liu, Yun; Porcar, Lionel; Pinkhassik, Eugene

2011-01-01

Hydrophobic monomers partially phase separate from saturated lipids when loaded into lipid bilayers in amounts exceeding a 1:1 monomer/lipid molar ratio. This conclusion is based on the agreement between two independent methods of examining the structure of monomer-loaded bilayers. Complete phase separation of monomers from lipids would result in an increase in bilayer thickness and a slight increase in the diameter of liposomes. A homogeneous distribution of monomers within the bilayer would not change the bilayer thickness and would lead to an increase in the liposome diameter. The increase in bilayer thickness, measured by the combination of small-angle neutron scattering (SANS) and small-angle X-ray scattering (SAXS), was approximately half of what was predicted for complete phase separation. The increase in liposome diameter, measured by dynamic light scattering (DLS), was intermediate between values predicted for a homogeneous distribution and complete phase separation. Combined SANS, SAXS, and DLS data suggest that at a 1.2 monomer/lipid ratio approximately half of the monomers are located in an interstitial layer sandwiched between lipid sheets. These results expand our understanding of using self-assembled bilayers as scaffolds for the directed covalent assembly of organic nanomaterials. In particular, the partial phase separation of monomers from lipids corroborates the successful creation of nanothin polymer materials with uniform imprinted nanopores. Pore-forming templates do not need to span the lipid bilayer to create a pore in the bilayer-templated films.

Micellar Surfactant Association in the Presence of a Glucoside-based Amphiphile Detected via High-Throughput Small Angle X-ray Scattering

Energy Technology Data Exchange (ETDEWEB)

Stanic, Vesna [Brazilian Synchrotron Light Source, Campinas (Brazil); Broadbent, Charlotte [Columbia Univ., New York, NY (United States). Engineering Dept.; DiMasi, Elaine [Brookhaven National Lab. (BNL), Upton, NY (United States). Photon Sciences Division; Galleguillos, Ramiro [Lubrizol Advanced Materials, Cleveland, OH (United States); Woodward, Valerie [Lubrizol Advanced Materials, Cleveland, OH (United States)

2016-11-14

The interactions of mixtures of anionic and amphoteric surfactants with sugar amphiphiles were studied via high throughput small angle x-ray scattering (SAXS). The sugar amphiphile was composed of Caprate, Caprylate, and Oleate mixed ester of methyl glucoside, MeGCCO. Optimal surfactant interactions are sought which have desirable physical properties, which must be identified in a cost effective manner that can access the large phase space of possible molecular combinations. X-ray scattering patterns obtained via high throughput SAXS can probe a combinatorial sample space and reveal the incorporation of MeGCCO into the micelles and the molecular associations between surfactant molecules. Such data make it possible to efficiently assess the effects of the new amphiphiles in the formulation. A specific finding of this study is that formulations containing comparatively monodisperse and homogeneous surfactant mixtures can be reliably tuned by addition of NaCl, which swells the surfactant micelles with a monotonic dependence on salt concentration. In contrast, the presence of multiple different surfactants destroys clear correlations with NaCl concentration, even in otherwise similar series of formulations.

Effects of blending poly(D,L-lactide) with poly(ethylene glycol) on the higher-order crystalline structures of poly(ethylene glycol) as revealed by small-angle X-ray scattering

International Nuclear Information System (INIS)

Tien, N D; Kimura, G; Yamashiro, Y; Fujiwara, H; Sasaki, S; Sakurai, S; Hoa, T P; Mochizuki, M

2011-01-01

Effects of blending poly(lactic acid) (PLA) with poly(ethylene glycol) (PEG) on higher-order crystalline structures of PEG were examined using small-angle X-ray scattering (SAXS). For this purpose, the fact that two polymers are both crystalline makes situtation much complicated. To simplify, non-crystalline PLA is suitable. Thus, we used poly(D,L-lactic acid) (DLPLA), which is random copolymer comprising D- and L-lactic acid moieties. Multiple scattering peaks arising from the regular crystalline lamellar structure were observed for the PEG homopolymer and the blends. Surprisingly, the structure is much more regular for the blend DLPLA/PEG at composition of 20/80 wt.% than for the PEG homopolymer. Also for this blend sample as well as for a PEG homopolymer, very peculiar SAXS profiles were observed just 1 deg. C below T m of PEG. This is found to be a particle scattering of plate-like objects, which has never been reported for polymer blends or crystalline polymers. Futhermore, it was found that there was strong hysteresis of the higher-order structure formation.

Casein micelles and their internal structure

NARCIS (Netherlands)

de Kruif, C.G.; Huppertz, T.; Urban, V.S.; Petukhov, A.V.

2012-01-01

The internalstructure of caseinmicelles was studied by calculating the small-angle neutron and X-ray scattering and static light scattering spectrum (SANS, SAXS, SLS) as a function of the scattering contrast and composition. We predicted experimental SANS, SAXS, SLS spectra self consistently using

SAXS analysis of a soluble cytosolic NgBR construct including extracellular and transmembrane domains.

Directory of Open Access Journals (Sweden)

Joshua Holcomb

Full Text Available The Nogo-B receptor (NgBR is involved in oncogenic Ras signaling through directly binding to farnesylated Ras. It recruits farnesylated Ras to the non-lipid-raft membrane for interaction with downstream effectors. However, the cytosolic domain of NgBR itself is only partially folded. The lack of several conserved secondary structural elements makes this domain unlikely to form a complete farnesyl binding pocket. We find that inclusion of the extracellular and transmembrane domains that contain additional conserved residues to the cytosolic region results in a well folded protein with a similar size and shape to the E.coli cis-isoprenyl transferase (UPPs. Small Angle X-ray Scattering (SAXS analysis reveals the radius of gyration (Rg of our NgBR construct to be 18.2 Å with a maximum particle dimension (Dmax of 61.0 Å. Ab initio shape modeling returns a globular molecular envelope with an estimated molecular weight of 23.0 kD closely correlated with the calculated molecular weight. Both Kratky plot and pair distribution function of NgBR scattering reveal a bell shaped peak which is characteristic of a single globularly folded protein. In addition, circular dichroism (CD analysis reveals that our construct has the secondary structure contents similar to the UPPs. However, this result does not agree with the currently accepted topological orientation of NgBR which might partition this construct into three separate domains. This discrepancy suggests another possible NgBR topology and lends insight into a potential molecular basis of how NgBR facilitates farnesylated Ras recruitment.

Phonon dispersion curves for CsCN

International Nuclear Information System (INIS)

Gaur, N.K.; Singh, Preeti; Rini, E.G.; Galgale, Jyostna; Singh, R.K.

2004-01-01

The motivation for the present work was gained from the recent publication on phonon dispersion curves (PDCs) of CsCN from the neutron scattering technique. We have applied the extended three-body force shell model (ETSM) by incorporating the effect of coupling between the translation modes and the orientation of cyanide molecules for the description of phonon dispersion curves of CsCN between the temperatures 195 and 295 K. Our results on PDCs in symmetric direction are in good agreement with the experimental data measured with inelastic neutron scattering technique. (author)

Small-angle x-ray scattering from the early growth stages of zeolite A

International Nuclear Information System (INIS)

Singh, P.; White, J.

1999-01-01

Full text: The work presented here with the use of SAXS (Small-Angle X-ray Scattering) is in attempt to identify a different paradigm to the organic template induced crystallization of zeolites, in particular zeolite 'A'. The reactions have been followed by small angle X-ray scattering from the time of first mixing of the constituents until the final separation of zeolite A crystals. The processes happening during the growth are expected to follow successive transformation of intermediate metastable phases until the formation of thermodynamically most stable phase and scattering signatures from these developments may be useful for extracting interesting information about the processes in situ. The scattering functions from a synthesis system of zeolite 'A' at the initial and final stage of reaction are presented.The different growth processes of zeolite 'A' from different silicate and aluminium sources are found. The differences are attributed to different rate limiting steps in the syntheses

Proceedings of the workshop on small angle scattering data analysis. Micelle related topics

Energy Technology Data Exchange (ETDEWEB)

Yamaguchi, Toshio [Fukuoka Univ. (Japan). Faculty of Science; Furusaka, Michihiro; Ohtomo, Toshiya [eds.

1996-02-01

This workshop was held on December 13 and 14, 1995 at National Laboratory for High Energy Physics. At the workshop, the purpose of the workshop was explained, and lectures were given on the research on superhigh molecular structure by small angle neutron scattering, the verification of the reliability of WINK data (absolute intensity), the analysis of WINK data, the new data program of SAN, small angle X-ray scattering data analysis program (SAXS), the basis of the analysis of micelle system, analysis software manual and practice program Q-I(Q) ver 1.0, various analysis methods for small angle scattering and contrast modulation method and others, the ordering of and the countermeasures to the problems of WINK, and the hereafter of KENS small angle scattering facility. How to treat the analysis related to micelle, how to save WINK and how to install the SAN/reflectometer are the matters to be discussed at the workshop. In this book, the summaries of the lectures are collected. (K.I.)

SAXS observation of structural evolution of heated olefin

International Nuclear Information System (INIS)

Sun Minhua; Mou Hongchen; Wang Yuxi; Li Demin; Wang Aiping; Ma Congxiao; Cheng Weidong; Wang Dan; Liu Jia

2007-01-01

Structural evolution of olefin during its heating process was observed with SAXS method at Beijing Synchrotron Radiation Facility. The mean square fluctuation of electron density increased from 468.5 nm -2 at 22 degree C to 2416 nm -2 at 100 degree C, while the electronic gyration radius decreased from 11.61 nm at 22 degree C to 11.16 nm at 100 degree C. Therefore, the olefin softens as a result of the increased thermal motion of the molecules, rather than the shrinking size of fundamental structural units of olefin. (authors)

BeppoSAX Observations of 3C 279

International Nuclear Information System (INIS)

Maraschi, L.; Celotti, A.; Fossati, G.; Ghisellini, G.; Tagliaferri, G.; Pian, E.; Treves, A.; Raiteri, C.; Villata, M.; Bassani, L.; Cappi, M.; Chiappetti, L.; Comastri, A.; Frontera, F.; Giarrusso, S.; Grandi, P.; Molendi, S.; Palumbo, G.; Perola, C.; Salvati, M.; Tanzi, E.G.; Urry, C.M.

1999-01-01

We report on BeppoSAX AO1 Core Program observations of 3C 279, performed in January 1997. 3C 279 was found in a low state, with constant X-ray flux in the 5 observations. The spectra obtained with the LECS and MECS instruments combining the 5 observations are well fitted by a single power law with energy spectral index α = 0.64 ± 0.03 and Galactic absorption. The source is weakly detected by the PDS instrument. Comparison with simultaneous γ-ray data obtained by EGRET and with previous multifrequency measurements shows that the X-ray emission is well correlated with the γ-ray emission over long timescales

BeppoSAX Observations of 3C 279

Energy Technology Data Exchange (ETDEWEB)

Maraschi, L.; Celotti, A.; Fossati, G.; Ghisellini, G.; Tagliaferri, G.; Pian, E.; Treves, A.; Raiteri, C.; Villata, M.; Bassani, L.; Cappi, M.; Chiappetti, L.; Comastri, A.; Frontera, F.; Giarrusso, S.; Grandi, P.; Molendi, S.; Palumbo, G.; Perola, C.; Salvati, M.; Tanzi, E.G.; Urry, C.M

1999-01-01

We report on BeppoSAX AO1 Core Program observations of 3C 279, performed in January 1997. 3C 279 was found in a low state, with constant X-ray flux in the 5 observations. The spectra obtained with the LECS and MECS instruments combining the 5 observations are well fitted by a single power law with energy spectral index {alpha} = 0.64 {+-} 0.03 and Galactic absorption. The source is weakly detected by the PDS instrument. Comparison with simultaneous {gamma}-ray data obtained by EGRET and with previous multifrequency measurements shows that the X-ray emission is well correlated with the {gamma}-ray emission over long timescales.

Microstructure of magnetite doped elastomers investigated by SAXS and SANS

Czech Academy of Sciences Publication Activity Database

Balasoiu, M.; Craus, M. L.; Kuklin, A. I.; Pleštil, Josef; Haramus, V.; Islamov, A. H.; Erhan, R.; Anitas, E. M.; Lozovan, M.; Tripadus, V.; Petrescu, C.; Savu, D.; Savu, S.; Bica, I.

2008-01-01

Roč. 10, č. 11 (2008), s. 2932-2935 ISSN 1454-4164. [International Balkan Workshop on Applied Physics /9./. Constanta, 07.07.2008-09.07.2008] Institutional research plan: CEZ:AV0Z40500505 Keywords : SANS * SAXS * magnetic elastomers * ferrofluids Subject RIV: CD - Macromolecular Chemistry Impact factor: 0.577, year: 2008 http://inoe.inoe.ro/joam/index.php?option=magazine&op=list&revid=32

INTEGRAL observations of SAX J1808.4-3658 currently in outburst

DEFF Research Database (Denmark)

Del Santo, M.; Bozzo, E.; Kuulkers, E.

2015-01-01

The latest INTEGRAL Galactic Bulge monitoring (ATel #438) was performed during revolution 1529 on 2015 April 12 starting at 18:15 UT (57124.761 MJD) for a total of 12462 seconds. We report on the IBIS/ISGRI detection of the new outburst from the millisecond X-ray pulsar SAX J1808.4-3658 (ATels...

Analysis of the aggregation structure from amphiphilic block copolymers in solutions by small-angle x-ray scattering

CERN Document Server

Rong Li Xia; Wang Jun; Wei Liu He; Li Fu Mian; Li Zi Chen

2002-01-01

The aggregation structure of polystyrene-p vinyl benzoic amphiphilic block copolymers which were prepared in different conditions was investigated by synchrotron radiation small-angle x-ray scattering (SAXS). The micelle was self-assembled in selective solvents of the block copolymers. Authors' results demonstrate that the structure of the micelle depends on the factors, such as the composition of the copolymers, the nature of the solvent and the concentration of the solution

A Journey Between Two Curves

Directory of Open Access Journals (Sweden)

Sergey A. Cherkis

2007-03-01

Full Text Available A typical solution of an integrable system is described in terms of a holomorphic curve and a line bundle over it. The curve provides the action variables while the time evolution is a linear flow on the curve's Jacobian. Even though the system of Nahm equations is closely related to the Hitchin system, the curves appearing in these two cases have very different nature. The former can be described in terms of some classical scattering problem while the latter provides a solution to some Seiberg-Witten gauge theory. This note identifies the setup in which one can formulate the question of relating the two curves.

Neutron scattering shows a droplet of oleic acid at the center of the BAMLET complex.

Science.gov (United States)

Rath, Emma M; Duff, Anthony P; Gilbert, Elliot P; Doherty, Greg; Knott, Robert B; Church, W Bret

2017-07-01

The anti-cancer complex, Bovine Alpha-lactalbumin Made LEthal to Tumors (BAMLET), has intriguing broad-spectrum anti-cancer activity. Although aspects of BAMLET's anti-cancer mechanism are still not known, it is understood that it involves the oleic acid or oleate component of BAMLET being preferentially released into cancer cell membranes leading to increased membrane permeability and lysis. The structure of the protein component of BAMLET has previously been elucidated by small angle X-ray scattering (SAXS) to be partially unfolded and dramatically enlarged. However, the structure of the oleic acid component of BAMLET and its disposition with respect to the protein component was not revealed as oleic acid has the same X-ray scattering length density (SLD) as water. Employing the difference in the neutron SLDs of hydrogen and deuterium, we carried out solvent contrast variation small angle neutron scattering (SANS) experiments of hydrogenated BAMLET in deuterated water buffers, to reveal the size, shape, and disposition of the oleic acid component of BAMLET. Our resulting analysis and models generated from SANS and SAXS data indicate that oleic acid forms a spherical droplet of oil incompletely encapsulated by the partially unfolded protein component. This model provides insight into the anti-cancer mechanism of this cache of lipid. The model also reveals a protein component "tail" not associated with the oleic acid component that is able to interact with the tail of other BAMLET molecules, providing a plausible explanation of how BAMLET readily forms aggregates. Proteins 2017; 85:1371-1378. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

Applications of micro-SAXS/WAXS to study polymer fibers

International Nuclear Information System (INIS)

Riekel, C.

2003-01-01

Instrumentation and selected applications for X-ray microdiffraction experiments on polymer and biopolymer fibers at the European Synchrotron Radiation Facility (ESRF) microfocus beamline are reviewed. Combined SAXS/WAXS experiments can be performed on single fibers with a beam size down to about 5 μm. WAXS experiments can be performed down to about 2 μm and in exceptional cases down to 0.1 μm beam size. The instrumental possibilities are demonstrated for the production line of spider silk

Applications of micro-SAXS/WAXS to study polymer fibers

Energy Technology Data Exchange (ETDEWEB)

Riekel, C. E-mail: riekel@esrf.fr

2003-01-01

Instrumentation and selected applications for X-ray microdiffraction experiments on polymer and biopolymer fibers at the European Synchrotron Radiation Facility (ESRF) microfocus beamline are reviewed. Combined SAXS/WAXS experiments can be performed on single fibers with a beam size down to about 5 {mu}m. WAXS experiments can be performed down to about 2 {mu}m and in exceptional cases down to 0.1 {mu}m beam size. The instrumental possibilities are demonstrated for the production line of spider silk.

Applications of micro-SAXS/WAXS to study polymer fibers

Science.gov (United States)

Riekel, C.

2003-01-01

Instrumentation and selected applications for X-ray microdiffraction experiments on polymer and biopolymer fibers at the European Synchrotron Radiation Facility (ESRF) microfocus beamline are reviewed. Combined SAXS/WAXS experiments can be performed on single fibers with a beam size down to about 5 μm. WAXS experiments can be performed down to about 2 μm and in exceptional cases down to 0.1 μm beam size. The instrumental possibilities are demonstrated for the production line of spider silk.

The influence of additives on the morphology and stability of roll-to-roll processed polymer solar cells studied through ex situ and in situ X-ray scattering

DEFF Research Database (Denmark)

Zawacka, Natalia Klaudia; Andersen, Thomas Rieks; Andreasen, Jens Wenzel

2014-01-01

-Vis Spectroscopy and Small Angle X-ray Scattering (SAXS) for cells prepared with 1-chloronaphthalene (CN), N-methyl-2-pyrrolidone (NMP) and 1,3-dimethyl-barbituric acid (BARB) as processing additives. The studies suggested that the use of these additives resulted in films with improved morphology and electrical...

The new NCPSS BL19U2 beamline at the SSRF for small-angle X-ray scattering from biological macromolecules in solution.

Science.gov (United States)

Li, Na; Li, Xiuhong; Wang, Yuzhu; Liu, Guangfeng; Zhou, Ping; Wu, Hongjin; Hong, Chunxia; Bian, Fenggang; Zhang, Rongguang

2016-10-01

The beamline BL19U2 is located in the Shanghai Synchrotron Radiation Facility (SSRF) and is its first beamline dedicated to biological material small-angle X-ray scattering (BioSAXS). The electrons come from an undulator which can provide high brilliance for the BL19U2 end stations. A double flat silicon crystal (111) monochromator is used in BL19U2, with a tunable monochromatic photon energy ranging from 7 to 15 keV. To meet the rapidly growing demands of crystallographers, biochemists and structural biologists, the BioSAXS beamline allows manual and automatic sample loading/unloading. A Pilatus 1M detector (Dectris) is employed for data collection, characterized by a high dynamic range and a short readout time. The highly automated data processing pipeline SASFLOW was integrated into BL19U2, with help from the BioSAXS group of the European Molecular Biology Laboratory (EMBL, Hamburg), which provides a user-friendly interface for data processing. The BL19U2 beamline was officially opened to users in March 2015. To date, feedback from users has been positive and the number of experimental proposals at BL19U2 is increasing. A description of the new BioSAXS beamline and the setup characteristics is given, together with examples of data obtained.

Discovery of decaHz flaring in SAX J1808.4-3658

NARCIS (Netherlands)

Bult, P.

2014-01-01

We report on the discovery of strong decaHz flaring in the early decay of two out of five outbursts of the accreting millisecond X-ray pulsar SAX J1808.4-3658. The decaHz flaring switches on and, after ~3 days, off again, on a time scale of 1-2 hours. When the flaring is present, the total 0.05-10

First superburst observed by INTEGRAL, from SAX J1747.0-2853

DEFF Research Database (Denmark)

Chenevez, Jérôme; Brandt, Søren; Kuulkers, E.

2011-01-01

A re-analysis of the INTEGRAL Galactic Bulge monitoring observation on February 13 (ATel #3172) shows that the flaring behaviour reported from SAX J1747.0-2853 is in fact due to a superburst. The event started on February 13, 2011 at 13:01:40 UTC with a 2 minutes spike, but the JEM-X (3-30 keV) s...

What can BeppoSAX tell us about short GRBs: An update from the subsecond GRB project

International Nuclear Information System (INIS)

Gandolfi, G.; Costa, E.; Feroci, M.; Piro, L.; Smith, M.J.S.; Muller, J.M.; Coletta, A.; Celidonio, G.; Di Ciolo, L.; Paolino, A.; Tarei, G.; Tassone, G.; Frontera, F.

2000-01-01

We present some statistical considerations on the BeppoSAX hunt for subsecond GRBs at the Scientific Operation Center. Archival analysis of a BATSE/SAX sub-sample of bursts indicates that the GRB Monitor is sensitive to short (≤2 sec) events, that are in fact ≅22% of the total. The non-detection of corresponding prompt X-ray counterparts to short bursts in the Wide Field Cameras, in about 3 years of operations, is discussed: with present data no implications on the X-to-γ-ray spectra of short vs. long GRBs may be inferred. Finally, the status of searching procedures at the SOC is reviewed

Direct investigations of deformation and yield induced structure transitions in polyamide 6 below glass transition temperature with WAXS and SAXS

DEFF Research Database (Denmark)

Guo, Huilong; Wang, Jiayi; Zhou, Chengbo

2015-01-01

Deformation and yield induced structure transitions of polyamide 6 (PA6) were detected with the combination of the wide- and small-angle X-ray scattering (WAXS and SAXS) at 30 degrees C below glass transition temperature (T-g) of PA6. During deformation, gamma-alpha phase transition was found...... at elastic stage. The concentrated stress in crystals at elastic stage provided adequate energy for the direct gamma-alpha phase transition under T-g. The force to promote the gamma-phase into a phase directly is insufficient at the yield stage and a transient phase as a compromise was formed. The transient...... phase was confirmed by DSC measurements and assisted the gamma-alpha phase transition indirectly. The gamma-phase slips into incomplete fragments at yield point, and the parts along tensile direction are responsible for the formation of transient phase. The gamma-fragments after yield is oriented...

Detection of flaws below curved surfaces

International Nuclear Information System (INIS)

Elsley, R.K.; Addison, R.C.; Graham, L.J.

1983-01-01

A measurement model has been developed to describe ultrasonic measurements made with circular piston transducers in parts with flat or cylindrically curved surfaces. The model includes noise terms to describe electrical noise, scatterer noise and echo noise as well as effects of attenuation, diffraction and Fresnel loss. An experimental procedure for calibrating the noise terms of the model was developed. Experimental measurements were made on a set of known flaws located beneath a cylindrically curved surface. The model was verified by using it to correct the experimental measurements to obtain the absolute scattering amplitude of the flaws. For longitudinal wave propagation within the part, the derived scattering amplitudes were consistent with predictions at internal angles of less than 30 0 . At larger angles, focusing and aberrations caused a lack of agreement; the model needs further refinement in this case. For shear waves, it was found that the frequency for optimum flaw detection in the presence of material noise is lower than that for longitudinal waves; lower frequency measurements are currently in progress. The measurement model was then used to make preliminary predictions of the best experimental measurement technique for the detection of cracks located under cylindrically curved surfaces

Identification of human breast pathologies by X-ray elastic scattering; Identificacao de patologias mamarias atraves do espalhamento elastico de raios X

Energy Technology Data Exchange (ETDEWEB)

Conceicao, Andre L.C.; Antoniassi, Marcelo; Poletti, Martin E., E-mail: andre_conceicao@yahoo.com.b [Universidade de Sao Paulo (FFCLRP/USP), Ribeirao Preto, SP (Brazil). Faculdade de Filosofia, Ciencias e Letras. Dept. de Fisica e Matematica

2011-07-01

In this paper we determine the scattering profiles of normal, benign and malignant human breast samples in a momentum transfer range of 0.07nm{sup -1} {<=}q{<=}70.55nm{sup -1}, resulted from combining WAXS (wide angle x-ray scattering) and SAXS (small angle x-ray scattering) data. The results showed considerable differences between the scattering profiles of each tissue type. Based on this fact, some parameters, representing structural features, were extracted from these scattering profiles and submitted to a discriminant analysis. From statistical analysis, the ratio between the peak intensities at q=19.8nm{sup -1} and q=13.9nm{sup -1} and the intensity of third order axial collagen peak arose as two potentials breast tissue classifiers and, from combining them it was possible differentiate among normal, benign and malignant lesions. (author)

SAXS study of growth of AgCl crystallites in photo chromic glass

International Nuclear Information System (INIS)

Takatohi, Urias E.; Bittencourt, Diomar; Watanabe, Shigueo

1996-01-01

A class of photo chromic glasses presents a reversible change in their optical absorption when exposed to light due to small silver halide crystals inside the glassy matrix. The silver halides crystals grow during the annealing of the glass. A base glass of 40 Si O 2 . 10 Al 2 O 3 .(16,1) K 2 O. (33,9) B 2 O 3 doped Ag CL and Cu O was produced and submited to different annealing programs, SAXS measurements were performed with samples annealed for 0.5h at temperatures from 480 O C to 620 O C and samples annealed at 600 0 C for times from 0.25h to 1.25h. Guinier radius (R g ) for samples annealed between 570 and 620 0 C show crescent growth rate in the interval. For samples annealed at 600 0 C for different times t a R 3 g = Kt law can be observed. Variation on optical absorption spectra for samples exposed to light show a correlation with the SAXS results. (author)

Myelin structure is a key difference in the x-ray scattering signature between meningioma, schwannoma and glioblastoma multiforme

International Nuclear Information System (INIS)

Falzon, G; Pearson, S; Murison, R; Hall, C; Siu, K; Round, A; Schueltke, E; Kaye, A H; Lewis, R

2007-01-01

Small angle x-ray scattering (SAXS) patterns of benign and malignant brain tumour tissue were examined. Independent component analysis was used to find a feature set representing the images collected. A set of coefficients was then used to describe each image, which allowed the use of the statistical technique of flexible discriminant analysis to discover a hidden order in the data set. The key difference was found to be in the intensity and spectral content of the second and fourth order myelin scattering peaks. This has clearly demonstrated that significant differences in the structure of myelin exist in the highly malignant glioblastoma multiforme as opposed to the benign: meningioma and schwannoma

BioXTAS RAW, a software program for high-throughput automated small-angle X-ray scattering data reduction and preliminary analysis

DEFF Research Database (Denmark)

Nielsen, S.S.; Toft, K.N.; Snakenborg, Detlef

2009-01-01

A fully open source software program for automated two-dimensional and one-dimensional data reduction and preliminary analysis of isotropic small-angle X-ray scattering (SAXS) data is presented. The program is freely distributed, following the open-source philosophy, and does not rely on any...... commercial software packages. BioXTAS RAW is a fully automated program that, via an online feature, reads raw two-dimensional SAXS detector output files and processes and plots data as the data files are created during measurement sessions. The software handles all steps in the data reduction. This includes...... mask creation, radial averaging, error bar calculation, artifact removal, normalization and q calibration. Further data reduction such as background subtraction and absolute intensity scaling is fast and easy via the graphical user interface. BioXTAS RAW also provides preliminary analysis of one...

Small-angle x-ray scattering study of kinetics of spinodal decomposition in N-isopropylacrylamide gels

International Nuclear Information System (INIS)

Liao, G.; Xie, Y.; Ludwig, K.F. Jr.; Bansil, R.; Gallagher, P.; Xie, Y.; Gallagher, P.

1999-01-01

We present synchrotron-based time-resolved small-angle x-ray scattering (SAXS) measurements of spinodal decomposition in a covalently cross-linked N-isopropylacrylamide gel. The range of wave numbers examined is well beyond the position of the maximum in the structure factor S(q,t). The equilibrium structure factor is described by the sum of a Lorentzian and a Gaussian. Following a temperature jump into the two phase region, the scattered intensity increases with time and eventually saturates. For early times the linear Cahn-Hilliard-Cook (CHC) theory can be used to describe the time evolution of the scattered intensity. From this analysis we found that the growth rate R(q) is linearly dependent on q 2 , in agreement with mean-field theoretical predictions. However the Onsager transport coefficient Λ(q)∼q -4 , which is stronger than the q dependence predicted by the mean-field theory. We found that the growth rate R(q)>0, even though the wave numbers q probed by SAXS are greater than √ (2) q m where q m is the position of the peak of S(q,t), also in agreement with the mean-field predictions for a deep quench. We have also examined the range of validity of the linear CHC theory, and found that its breakdown occurs earlier at higher wave numbers. At later times, a pinning of the structure was observed. The relaxation to a final, microphase-separated morphology is faster and occurs earlier at the highest wave numbers, which probe length scales comparable to the average distance between crosslinks. copyright 1999 The American Physical Society

Investigating the origins of nanostructural variations in differential ethnic hair types using X-ray scattering techniques.

Science.gov (United States)

Wade, M; Tucker, I; Cunningham, P; Skinner, R; Bell, F; Lyons, T; Patten, K; Gonzalez, L; Wess, T

2013-10-01

Human hair is a major determinant of visual ethnic differentiation. Although hair types are celebrated as part of our ethnic diversity, the approach to hair care has made the assumption that hair types are structurally and chemically similar. Although this is clearly not the case at the macroscopic level, the intervention of many hair treatments is at the nanoscopic and molecular levels. The purpose of the work presented here is to identify the main nanoscopic and molecular hierarchical differences across five different ethnic hair types from hair fibres taken exclusively from the scalp. These are Afro (subdivided into elastic 'rubber' and softer non-elastic 'soft'), Chinese, European and Mullato (mixed race). Small angle X-Ray scattering (SAXS) is a technique capable of resolving nanostructural variations in complex materials. Individual hair fibres from different ethnic hair types were used to investigate structural features found in common and also specific to each type. Simultaneous wide angle X-Ray scattering (WAXS) was used to analyse the submolecular level structure of the fibrous keratin present. The data sets from both techniques were analysed with principal component analysis (PCA) to identify underlying variables. Principal component analysis of both SAXS and WAXS data was shown to discriminate the scattering signal between different hair types. The X-ray scattering results show a common underlying keratin intermediate filament (KIF) structure. However, distinct differences were observed in the preferential orientation and intensity signal from the lipid component of the hair. In addition, differences were observed in the intensity distribution of the very low-angle sample-dependent diffuse scatter surrounding the 'beamstop.' The results indicate that the fibrous keratin scaffold remains consistent between ethnic hair types. The hierarchies made by these may be modulated by variation in the content of keratin-associated proteins (KAPs) and lipids that

Morphological and structural characterization of PHBV/organoclay nanocomposites by small angle X-ray scattering

Energy Technology Data Exchange (ETDEWEB)

Carli, Larissa N., E-mail: lncarli@ucs.br [Instituto de Quimica, Universidade Federal do Rio Grande do Sul, Av. Bento Goncalves, 9500, Porto Alegre, 91501-970, RS (Brazil); Centro de Ciencias Exatas e Tecnologia, Universidade de Caxias do Sul, Rua Francisco Getulio Vargas, 1130, Caxias do Sul, 95070-560, RS (Brazil); Bianchi, Otavio, E-mail: obianchi@ucs.br [Centro de Ciencias Exatas e Tecnologia, Universidade de Caxias do Sul, Rua Francisco Getulio Vargas, 1130, Caxias do Sul, 95070-560, RS (Brazil); Machado, Giovanna, E-mail: giovannamachado@uol.com.br [Centro de Tecnologias Estrategicas do Nordeste, Av. Prof. Luiz Freire, 01, Cidade Universitaria, Recife, 50740-540, PE (Brazil); Programa de Pos-Graduacao de Materiais, Universidade Federal de Pernambuco, Av. Prof. Moraes Rego, 1235, Recife, 50670-901, PE (Brazil); Crespo, Janaina S., E-mail: jscrespo@ucs.br [Centro de Ciencias Exatas e Tecnologia, Universidade de Caxias do Sul, Rua Francisco Getulio Vargas, 1130, Caxias do Sul, 95070-560, RS (Brazil); Mauler, Raquel S., E-mail: raquel.mauler@ufrgs.br [Instituto de Quimica, Universidade Federal do Rio Grande do Sul, Av. Bento Goncalves, 9500, Porto Alegre, 91501-970, RS (Brazil)

2013-03-01

In this work, the morphological and structural behaviors of poly(hydroxybutyrate-co-hydroxyvalerate) (PHBV) nanocomposites were investigated using small angle X-ray scattering (SAXS), wide angle X-ray diffraction (WAXD) and transmission electron microscopy (TEM). The nanocomposites with 1, 3 and 5 wt.% of organically modified montmorillonite Cloisite Registered-Sign 30B (OMMT) were prepared by melt processing in a twin screw extruder using two different processing conditions (low and high shear intensity). The lamellar long period of the polymer was lower for the nanocomposites, with high polydispersity values. However, the crystalline thickness increased with the clay content and was independent of the processing conditions. This behavior resulted in a high linear crystallinity of the nanocomposites with 3 and 5 wt.% OMMT. The disruption factor ({beta}) was in agreement with the WAXD and TEM findings, indicating a good dispersion of the nanoparticles in the PHBV matrix with 3 wt.% of OMMT during the high shear intensity of melt processing. Highlights: Black-Right-Pointing-Pointer SAXS was used for morphological and crystalline studies of PHBV/OMMT nanocomposites. Black-Right-Pointing-Pointer The crystalline structure was influenced by the presence of clay. Black-Right-Pointing-Pointer The degree of clay dispersion in a polymer matrix was quantified. Black-Right-Pointing-Pointer The morphology comprised exfoliated particles, nanoscale and microscale clusters. Black-Right-Pointing-Pointer The results obtained by SAXS agreed well with TEM and WAXD results.

Protein crowding in solution, frozen and freeze-dried states: small-angle neutron and X-ray scattering study of lysozyme/sorbitol/water systems

Science.gov (United States)

Krueger, Susan; Khodadadi, Sheila; Clark, Nicholas; McAuley, Arnold; Cristiglio, Viviana; Theyencheri, Narayanan; Curtis, Joseph; Shalaev, Evgenyi

2015-03-01

For effective preservation, proteins are often stored as frozen solutions or in glassy states using a freeze-drying process. However, aggregation is often observed after freeze-thaw or reconstitution of freeze-dried powder and the stability of the protein is no longer assured. In this study, small-angle neutron and X-ray scattering (SANS and SAXS) have been used to investigate changes in protein-protein interaction distances of a model protein/cryoprotectant system of lysozyme/sorbitol/water, under representative pharmaceutical processing conditions. The results demonstrate the utility of SAXS and SANS methods to monitor protein crowding at different stages of freezing and drying. The SANS measurements of solution samples showed at least one protein interaction peak corresponding to an interaction distance of ~ 90 Å. In the frozen state, two protein interaction peaks were observed by SANS with corresponding interaction distances at 40 Å as well as 90 Å. On the other hand, both SAXS and SANS data for freeze-dried samples showed three peaks, suggesting interaction distances ranging from ~ 15 Å to 170 Å. Possible interpretations of these interaction peaks will be discussed, as well as the role of sorbitol as a cryoprotectant during the freezing and drying process.

Small-angle X-ray scattering on growth of AgCl crystallites in photochromic glasses

International Nuclear Information System (INIS)

Takatohi, U.E.; Bittencourt, D.R.S.; Watanabe, S.

1997-01-01

Reversible changes in the optical properties of photochromic glasses are observed owing to the presence of small silver halide crystals inside the glassy matrix. These crystals grow during the glass heat-treatment processing. Samples with molar composition of 40SiO 2 .10Al 2 O 3 .16.1K 2 O.33.9B 2 O 3 , doped with AgCl and CuO, were produced and submitted to different heat treatments: (i) for 0.5 h at temperatures from 753 to 893 K and (ii) at 873 K for periods of time from 0.25 to 1.25 h. Small-angle X-ray scattering (SAXS) was used to characterize the samples. The samples heat treated between 843 and 893 K presented an increasing growth rate of the Guinier radius (R g ). Samples heat treated at a fixed temperature of 873 K and different time t showed a law R g 3 = kt + c. Variations in the optical absorbance at 280 nm and the additional absorbance spectra of samples exposed to light showed correlation with the SAXS results. (orig.)

The curve shortening problem

CERN Document Server

Chou, Kai-Seng

2001-01-01

Although research in curve shortening flow has been very active for nearly 20 years, the results of those efforts have remained scattered throughout the literature. For the first time, The Curve Shortening Problem collects and illuminates those results in a comprehensive, rigorous, and self-contained account of the fundamental results.The authors present a complete treatment of the Gage-Hamilton theorem, a clear, detailed exposition of Grayson''s convexity theorem, a systematic discussion of invariant solutions, applications to the existence of simple closed geodesics on a surface, and a new, almost convexity theorem for the generalized curve shortening problem.Many questions regarding curve shortening remain outstanding. With its careful exposition and complete guide to the literature, The Curve Shortening Problem provides not only an outstanding starting point for graduate students and new investigations, but a superb reference that presents intriguing new results for those already active in the field.

Discovery of kilohertz QPOs in RXTE observations of SAX J1748.9-2021

NARCIS (Netherlands)

Altamirano, D.; Patruno, A.; Watts, A.; Armas Padilla, M.; Cavecchi, Y.; Degenaar, N.; Kalamkar, M.; Kaur, R.; Soleri, P.; Yang, Y.J.; van der Klis, M.; Wijnands, R.; Casella, P.; Linares, M.; Rea, N.

We report on RXTE observations of the ongoing outburst of the accreting millisecond X-ray pulsar SAX J1748.9-2021 (Altamirano et al. 2008, 674, 45A, see ATEL #2360 and #2407). Since the first detection of intermittent pulsations on January 27th, 2010, observations have been carried out on a daily

Small angle X-ray scattering study on the conformation of polystyrene in the anti-solvent process of supercritical fluids

International Nuclear Information System (INIS)

Liu Yi; Wang Hongli; Zhao Xin; Chen Na; Li Dan; Liu Zhimin; Han Buxing; Rong Lixia; Zhao Hui; Wang Jun; Dong Baozhong

2003-01-01

The conformation of polystyrene in the anti-solvent process of supercritical fluids (compressed CO 2 + polystyrene + tetrahydrofuran) is studied by synchrotron radiation X-ray small angle scattering (SAXS). Coil-to-globule transform of polystyrene chain is observed with increasing the concentration of CO 2 . It is found that polystyrene coils at the pressure lower than cloud point pressure (p c ) and changes into globule with uniform density at the pressure higher than p c

Ion track annealing in quartz investigated by small angle X-ray scattering

Energy Technology Data Exchange (ETDEWEB)

Schauries, D.; Afra, B.; Rodriguez, M.D. [Department of Electronic Materials Engineering, Research School of Physics and Engineering, The Australian National University, Canberra, ACT 2601 (Australia); Trautmann, C. [GSI Helmholtz Centre for Heavy Ion Research, Planckstrasse 1, 64291 Darmstadt (Germany); Technische Universität Darmstadt, 64287 Darmstadt (Germany); Hawley, A. [Australian Synchrotron, 800 Blackburn Road, Clayton, VIC 3168 (Australia); Kluth, P. [Department of Electronic Materials Engineering, Research School of Physics and Engineering, The Australian National University, Canberra, ACT 2601 (Australia)

2015-12-15

We report on the reduction of cross-section and length of amorphous ion tracks embedded within crystalline quartz during thermal annealing. The ion tracks were created via Au ion irradiation with an energy of 2.2 GeV. The use of synchrotron-based small angle X-ray scattering (SAXS) allowed characterization of the latent tracks, without the need for chemical etching. Temperatures between 900 and 1000 °C were required to see a notable change in track size. The shrinkage in cross-section and length was found to be comparable for tracks aligned perpendicular and parallel to the c-axis.

Effect of shear on cubic phases in gels of a diblock copolymer

DEFF Research Database (Denmark)

Hamley, I.W.; Pople, J.A.; Fairclough, J.P.A.

1998-01-01

The effect of shear on the orientation of cubic micellar phases formed by a poly(oxyethylene)poly(oxybutylene) diblock copolymer in aqueous solution has been investigated using small-angle x-ray scattering (SAXS) and small-angle neutron scattering (SANS). SAXS was performed on samples oriented in...

SAXS study of growth of AgCl crystallites in photo chromic glass

Energy Technology Data Exchange (ETDEWEB)

Takatohi, Urias E. [Instituto Adventista de Ensino, Sao Paulo, SP (Brazil); Bittencourt, Diomar; Watanabe, Shigueo [Sao Paulo Univ., SP (Brazil). Inst. de Fisica

1996-12-31

A class of photo chromic glasses presents a reversible change in their optical absorption when exposed to light due to small silver halide crystals inside the glassy matrix. The silver halides crystals grow during the annealing of the glass. A base glass of 40 Si O{sub 2}. 10 Al{sub 2} O{sub 3}.(16,1) K{sub 2} O. (33,9) B{sub 2} O{sub 3} doped Ag CL and Cu O was produced and submited to different annealing programs, SAXS measurements were performed with samples annealed for 0.5h at temperatures from 480{sup O}C to 620{sup O}C and samples annealed at 600{sup 0}C for times from 0.25h to 1.25h. Guinier radius (R{sub g}) for samples annealed between 570 and 620{sup 0}C show crescent growth rate in the interval. For samples annealed at 600{sup 0}C for different times t a R{sup 3}{sub g} = Kt law can be observed. Variation on optical absorption spectra for samples exposed to light show a correlation with the SAXS results. (author) 4 refs., 2 figs.

PCP and SAX-3/Robo Pathways Cooperate to Regulate Convergent Extension-Based Nerve Cord Assembly in C. elegans.

Science.gov (United States)

Shah, Pavak K; Tanner, Matthew R; Kovacevic, Ismar; Rankin, Aysha; Marshall, Teagan E; Noblett, Nathaniel; Tran, Nhan Nguyen; Roenspies, Tony; Hung, Jeffrey; Chen, Zheqian; Slatculescu, Cristina; Perkins, Theodore J; Bao, Zhirong; Colavita, Antonio

2017-04-24

Formation and resolution of multicellular rosettes can drive convergent extension (CE) type cell rearrangements during tissue morphogenesis. Rosette dynamics are regulated by both planar cell polarity (PCP)-dependent and -independent pathways. Here we show that CE is involved in ventral nerve cord (VNC) assembly in Caenorhabditis elegans. We show that a VANG-1/Van Gogh and PRKL-1/Prickle containing PCP pathway and a Slit-independent SAX-3/Robo pathway cooperate to regulate, via rosette intermediaries, the intercalation of post-mitotic neuronal cell bodies during VNC formation. We show that VANG-1 and SAX-3 are localized to contracting edges and rosette foci and act to specify edge contraction during rosette formation and to mediate timely rosette resolution. Simultaneous loss of both pathways severely curtails CE resulting in a shortened, anteriorly displaced distribution of VNC neurons at hatching. Our results establish rosette-based CE as an evolutionarily conserved mechanism of nerve cord morphogenesis and reveal a role for SAX-3/Robo in this process. Copyright © 2017 Elsevier Inc. All rights reserved.

Wavelet-based feature extraction applied to small-angle x-ray scattering patterns from breast tissue: a tool for differentiating between tissue types

International Nuclear Information System (INIS)

Falzon, G; Pearson, S; Murison, R; Hall, C; Siu, K; Evans, A; Rogers, K; Lewis, R

2006-01-01

This paper reports on the application of wavelet decomposition to small-angle x-ray scattering (SAXS) patterns from human breast tissue produced by a synchrotron source. The pixel intensities of SAXS patterns of normal, benign and malignant tissue types were transformed into wavelet coefficients. Statistical analysis found significant differences between the wavelet coefficients describing the patterns produced by different tissue types. These differences were then correlated with position in the image and have been linked to the supra-molecular structural changes that occur in breast tissue in the presence of disease. Specifically, results indicate that there are significant differences between healthy and diseased tissues in the wavelet coefficients that describe the peaks produced by the axial d-spacing of collagen. These differences suggest that a useful classification tool could be based upon the spectral information within the axial peaks

Collagen Orientation and Crystallite Size in Human Dentin: A Small Angle X-ray Scattering Study

Energy Technology Data Exchange (ETDEWEB)

Pople, John A

2001-03-29

The mechanical properties of dentin are largely determined by the intertubular dentin matrix, which is a complex composite of type I collagen fibers and a carbonate-rich apatite mineral phase. The authors perform a small angle x-ray scattering (SAXS) study on fully mineralized human dentin to quantify this fiber/mineral composite architecture from the nanoscopic through continuum length scales. The SAXS results were consistent with nucleation and growth of the apatite phase within periodic gaps in the collagen fibers. These mineralized fibers were perpendicular to the dentinal tubules and parallel with the mineralization growth front. Within the plane of the mineralization front, the mineralized collagen fibers were isotropic near the pulp, but became mildly anisotropic in the mid-dentin. Analysis of the data also indicated that near the pulp the mineral crystallites were approximately needle-like, and progressed to a more plate-like shape near the dentino-enamel junction. The thickness of these crystallites, {approx} 5 nm, did not vary significantly with position in the tooth. These results were considered within the context of dentinogenesis and maturation.

Phase behavior of polystyrene-block-poly(n-alkyl methacrylate) copolymers investigated by SANS, SAXS, and temperature-dependent FTIR spectroscopy

International Nuclear Information System (INIS)

Ryu, Du Yeol; Lee, Dong Hyun; Kim, Hye Jeong; Kim, Jin Kon; Jung, Y. M.; Kim, S. B.

2005-01-01

The phase behavior of polystyrene-block -poly(n-alkyl methacrylate) (PS-PnAMA) copolymer were investigated by Small-Angle Neutron Scattering (SANS), Small-Angle X-ray Scattering (SAXS), and temperature-dependent Fourier Transform Infrared (FTIR) spectroscopy. Also, the effect of hydrostatic pressure on the transition temperatures was studied by using SANS with pressure controller. Phase behavior was changed significantly with the change of alkyl number (n). For n = 2∼4, only Lower Disordered-to-Order Tansition (LDOT) was observed, whereas the Ordered-to-Disorder (ODT) was found for n =1 and n =6. Finally, a closed-loop phase behavior was found for n =5. Using incompressible random phase approximation, the segmental interactions (χ) between PS and PnAMA for all n values were obtained. The standard expression of χ = a + b/T (where T is the absolute temperature) was valid only for n =1 and n =6. But, this relationship was not valid any more for n = 2∼4. For n =5, a more complex behavior of χ upon temperature was observed. We investigated, by using temperature-dependent FTIR, the mechanism why as closed loop phase behavior was observed for n =5. Interestingly, the conformation of C-C-O stretching band of the PnPMA chain (n=5) (and thus the directional enthapic gain) was different in the two disordered states, and, therefore, the driving force to induce the disordered state at lower temperatures was different from that at higher temperatures

Combination of acoustic levitation with small angle scattering techniques and synchrotron radiation circular dichroism. Application to the study of protein solutions.

Science.gov (United States)

Cristiglio, Viviana; Grillo, Isabelle; Fomina, Margarita; Wien, Frank; Shalaev, Evgenyi; Novikov, Alexey; Brassamin, Séverine; Réfrégiers, Matthieu; Pérez, Javier; Hennet, Louis

2017-01-01

The acoustic levitation technique is a useful sample handling method for small solid and liquids samples, suspended in air by means of an ultrasonic field. This method was previously used at synchrotron sources for studying pharmaceutical liquids and protein solutions using x-ray diffraction and small angle x-ray scattering (SAXS). In this work we combined for the first time this containerless method with small angle neutron scattering (SANS) and synchrotron radiation circular dichroism (SRCD) to study the structural behavior of proteins in solutions during the water evaporation. SANS results are also compared with SAXS experiments. The aggregation behavior of 45μl droplets of lysozyme protein diluted in water was followed during the continuous increase of the sample concentration by evaporating the solvent. The evaporation kinetics was followed at different drying stage by SANS and SAXS with a good data quality. In a prospective work using SRCD, we also studied the evolution of the secondary structure of the myoglobin protein in water solution in the same evaporation conditions. Acoustic levitation was applied for the first time with SANS and the high performances of the used neutron instruments made it possible to monitor fast container-less reactions in situ. A preliminary work using SRCD shows the potentiality of its combination with acoustic levitation for studying the evolution of the protein structure with time. This multi-techniques approach could give novel insights into crystallization and self-assembly phenomena of biological compound with promising potential applications in pharmaceutical, food and cosmetics industry. This article is part of a Special Issue entitled "Science for Life" Guest Editor: Dr. Austen Angell, Dr. Salvatore Magazù and Dr. Federica Migliardo. Copyright © 2016 Elsevier B.V. All rights reserved.

Structural characterization of the human cerebral myelin sheath by small angle x-ray scattering

International Nuclear Information System (INIS)

De Felici, M; Felici, R; Ferrero, C; Tartari, A; Gambaccini, M; Finet, S

2008-01-01

Myelin is a multi-lamellar membrane surrounding neuronal axons and increasing their conduction velocity. When investigated by small-angle x-ray scattering (SAXS), the lamellar quasi-periodical arrangement of the myelin sheath gives rise to distinct peaks, which allow the determination of its molecular organization and the dimensions of its substructures. In this study we report on the myelin sheath structural determination carried out on a set of human brain tissue samples coming from surgical biopsies of two patients: a man around 60 and a woman nearly 90 years old. The samples were extracted either from white or grey cerebral matter and did not undergo any manipulation or chemical-physical treatment, which could possibly have altered their structure, except dipping them into a formalin solution for their conservation. Analysis of the scattered intensity from white matter of intact human cerebral tissue allowed the evaluation not only of the myelin sheath periodicity but also of its electronic charge density profile. In particular, the thicknesses of the cytoplasm and extracellular regions were established, as well as those of the hydrophilic polar heads and hydrophobic tails of the lipid bilayer. SAXS patterns were measured at several locations on each sample in order to establish the statistical variations of the structural parameters within a single sample and among different samples. This work demonstrates that a detailed structural analysis of the myelin sheath can also be carried out in randomly oriented samples of intact human white matter, which is of importance for studying the aetiology and evolution of the central nervous system pathologies inducing myelin degeneration.

Characterization of oxidized tannins: comparison of depolymerization methods, asymmetric flow field-flow fractionation and small-angle X-ray scattering.

Science.gov (United States)

Vernhet, Aude; Dubascoux, Stéphane; Cabane, Bernard; Fulcrand, Hélène; Dubreucq, Eric; Poncet-Legrand, Céline

2011-09-01

Condensed tannins are a major class of plant polyphenols. They play an important part in the colour and taste of foods and beverages. Due to their chemical reactivity, tannins are not stable once extracted from plants. A number of chemical reactions can take place, leading to structural changes of the native structures to give so-called derived tannins and pigments. This paper compares results obtained on native and oxidized tannins with different techniques: depolymerization followed by high-performance liquid chromatography analysis, small-angle X-ray scattering (SAXS) and asymmetric flow field-flow fractionation (AF4). Upon oxidation, new macromolecules were formed. Thioglycolysis experiments showed no evidence of molecular weight increase, but thioglycolysis yields drastically decreased. When oxidation was performed at high concentration (e.g., 10 g L(-1)), the weight average degree of polymerization determined from SAXS increased, whereas it remained stable when oxidation was done at low concentration (0.1 g L(-1)), indicating that the reaction was intramolecular, yet the conformations were different. Differences in terms of solubility were observed; ethanol being a better solvent than water. We also separated soluble and non-water-soluble species of a much oxidized fraction. Thioglycolysis showed no big differences between the two fractions, whereas SAXS and AF4 showed that insoluble macromolecules have a weight average molecular weight ten times higher than the soluble ones.

Light scattering by small particles

CERN Document Server

Hulst, H C van de

1981-01-01

""A must for researchers using the techniques of light scattering."" ? S. C. Snowdon, Journal of the Franklin InstituteThe measurement of light scattering of independent, homogeneous particles has many useful applications in physical chemistry, meteorology and astronomy. There is, however, a sizeable gap between the abstract formulae related to electromagnetic-wave-scattering phenomena, and the computation of reliable figures and curves. Dr. van de Hulst's book enables researchers to bridge that gap. The product of twelve years of work, it is an exhaustive study of light-scattering properties

Radio Pulse Search and X-Ray Monitoring of SAX J1808.4−3658: What Causes Its Orbital Evolution?

Energy Technology Data Exchange (ETDEWEB)

Patruno, Alessandro; King, Andrew R. [Leiden Observatory, Leiden University, Neils Bohrweg 2, 2333 CA, Leiden (Netherlands); Jaodand, Amruta; Hessels, Jason W. T. [ASTRON, the Netherlands Institute for Radio Astronomy, Postbus 2, 7900 AA, Dwingeloo (Netherlands); Kuiper, Lucien [SRON-National Institute for Space Research, Sorbonnelaan 2, NL-3584 CA, Utrecht (Netherlands); Bult, Peter; Wijnands, Rudy; Van der Klis, Michiel [Anton Pannekoek Institute for Astronomy, University of Amsterdam, Science Park 904, 1098 XH, Amsterdam (Netherlands); Knigge, Christian [University of Southampton, School of Physics and Astronomy, Southampton SO17 1BJ (United Kingdom)

2017-06-01

The accreting millisecond X-ray pulsar SAX J1808.4−3658 shows a peculiar orbital evolution that proceeds at a very fast pace. It is important to identify the underlying mechanism responsible for this behavior because it can help to understand how this system evolves and which physical processes (such as mass loss or spin–orbit coupling) are occurring in the binary. It has also been suggested that, when in quiescence, SAX J1808.4−3658 turns on as a radio pulsar, a circumstance that might provide a link between accreting millisecond pulsars and black-widow (BW) radio pulsars. In this work, we report the results of a deep radio pulsation search at 2 GHz using the Green Bank Telescope in 2014 August and an X-ray study of the 2015 outburst with Chandra , Swift XRT, and INTEGRAL . In quiescence, we detect no radio pulsations and place the strongest limit to date on the pulsed radio flux density of any accreting millisecond pulsar. We also find that the orbit of SAX J1808.4−3658 continues evolving at a fast pace. We compare the orbital evolution of SAX J1808.4−3658 to that of several other accreting and nonaccreting binaries, including BWs, redbacks, cataclysmic variables, black holes, and neutron stars in low-mass X-ray binaries. We discuss two possible scenarios: either the neutron star has a large moment of inertia and is ablating the donor, generating mass loss with an efficiency of 40%, or the donor star has a strong magnetic field of at least 1 kG and is undergoing quasi-cyclic variations due to spin–orbit coupling.

Structural evolution in the isothermal crystallization process of the molten nylon 10/10 traced by time-resolved infrared spectral measurements and synchrotron SAXS/WAXD measurements

International Nuclear Information System (INIS)

Tashiro, Kohji; Nishiyama, Asami; Tsuji, Sawako; Hashida, Tomoko; Hanesaka, Makoto; Takeda, Shinichi; Weiyu, Cao; Reddy, Kummetha Raghunatha; Masunaga, Hiroyasu; Sasaki, Sono; Takata, Masaki; Ito, Kazuki

2009-01-01

The structural evolution in the isothermal crystallization process of nylon 10/10 from the melt has been clarified concretely on the basis of the time-resolved infrared spectral measurement as well as the synchrotron wide-angle and small-angle X-ray scattering measurements. Immediately after the temperature jump from the melt to the crystallization point, the isolated domains consisting of the hydrogen-bonded random coils were formed in the melt, as revealed by Guinier plot of SAXS data and the infrared spectral data. With the passage of time these domains approached each other with stronger correlation as analyzed by Debye-Bueche equation. These domains transformed finally to the stacked crystalline lamellae, in which the conformationally-regularized methylene segments of the CO sides were connected each other by stronger intermolecular hydrogen bonds to form the crystal lattice.

Combining NMR and small angle X-ray and neutron scattering in the structural analysis of a ternary protein-RNA complex

International Nuclear Information System (INIS)

Hennig, Janosch; Wang, Iren; Sonntag, Miriam; Gabel, Frank; Sattler, Michael

2013-01-01

Many processes in the regulation of gene expression and signaling involve the formation of protein complexes involving multi-domain proteins. Individual domains that mediate protein-protein and protein-nucleic acid interactions are typically connected by flexible linkers, which contribute to conformational dynamics and enable the formation of complexes with distinct binding partners. Solution techniques are therefore required for structural analysis and to characterize potential conformational dynamics. Nuclear magnetic resonance spectroscopy (NMR) provides such information but often only sparse data are obtained with increasing molecular weight of the complexes. It is therefore beneficial to combine NMR data with additional structural restraints from complementary solution techniques. Small angle X-ray/neutron scattering (SAXS/SANS) data can be efficiently combined with NMR-derived information, either for validation or by providing additional restraints for structural analysis. Here, we show that the combination of SAXS and SANS data can help to refine structural models obtained from data-driven docking using HADDOCK based on sparse NMR data. The approach is demonstrated with the ternary protein-protein-RNA complex involving two RNA recognition motif (RRM) domains of Sex-lethal, the N-terminal cold shock domain of Upstream-to-N-Ras, and msl-2 mRNA. Based on chemical shift perturbations we have mapped protein-protein and protein-RNA interfaces and complemented this NMR-derived information with SAXS data, as well as SANS measurements on subunit-selectively deuterated samples of the ternary complex. Our results show that, while the use of SAXS data is beneficial, the additional combination with contrast variation in SANS data resolves remaining ambiguities and improves the docking based on chemical shift perturbations of the ternary protein-RNA complex.

Combining NMR and small angle X-ray and neutron scattering in the structural analysis of a ternary protein-RNA complex

Energy Technology Data Exchange (ETDEWEB)

Hennig, Janosch; Wang, Iren; Sonntag, Miriam [Institute of Structural Biology, Helmholtz Zentrum Muenchen (Germany); Gabel, Frank [Extremophiles and Large Molecular Assemblies Group (ELMA), Institut de Biologie Structurale (IBS) CEA-CNRS-UJF (France); Sattler, Michael, E-mail: sattler@helmholtz-muenchen.de [Institute of Structural Biology, Helmholtz Zentrum Muenchen (Germany)

2013-05-15

Many processes in the regulation of gene expression and signaling involve the formation of protein complexes involving multi-domain proteins. Individual domains that mediate protein-protein and protein-nucleic acid interactions are typically connected by flexible linkers, which contribute to conformational dynamics and enable the formation of complexes with distinct binding partners. Solution techniques are therefore required for structural analysis and to characterize potential conformational dynamics. Nuclear magnetic resonance spectroscopy (NMR) provides such information but often only sparse data are obtained with increasing molecular weight of the complexes. It is therefore beneficial to combine NMR data with additional structural restraints from complementary solution techniques. Small angle X-ray/neutron scattering (SAXS/SANS) data can be efficiently combined with NMR-derived information, either for validation or by providing additional restraints for structural analysis. Here, we show that the combination of SAXS and SANS data can help to refine structural models obtained from data-driven docking using HADDOCK based on sparse NMR data. The approach is demonstrated with the ternary protein-protein-RNA complex involving two RNA recognition motif (RRM) domains of Sex-lethal, the N-terminal cold shock domain of Upstream-to-N-Ras, and msl-2 mRNA. Based on chemical shift perturbations we have mapped protein-protein and protein-RNA interfaces and complemented this NMR-derived information with SAXS data, as well as SANS measurements on subunit-selectively deuterated samples of the ternary complex. Our results show that, while the use of SAXS data is beneficial, the additional combination with contrast variation in SANS data resolves remaining ambiguities and improves the docking based on chemical shift perturbations of the ternary protein-RNA complex.

Light Scattering of Rough Orthogonal Anisotropic Surfaces with Secondary Most Probable Slope Distributions

International Nuclear Information System (INIS)

Li Hai-Xia; Cheng Chuan-Fu

2011-01-01

We study the light scattering of an orthogonal anisotropic rough surface with secondary most probable slope distribution. It is found that the scattered intensity profiles have obvious secondary maxima, and in the direction perpendicular to the plane of incidence, the secondary maxima are oriented in a curve on the observation plane, which is called the orientation curve. By numerical calculation of the scattering wave fields with the height data of the sample, it is validated that the secondary maxima are induced by the side face element, which constitutes the prismoid structure of the anisotropic surface. We derive the equation of the quadratic orientation curve. Experimentally, we construct the system for light scattering measurement using a CCD. The scattered intensity profiles are extracted from the images at different angles of incidence along the orientation curves. The experimental results conform to the theory. (fundamental areas of phenomenology(including applications))

Nano-crystal growth in cordierite glass ceramics studied with X-ray scattering

Energy Technology Data Exchange (ETDEWEB)

Bras, Wim; Clark, Simon M.; Greaves, G. N.; Kunz, Martin; van Beek, W.; Radmilovic, V.

2009-01-16

The development of monodisperse crystalline particles in cordierite glass doped with Cr3+ after a two-step heat treatment is elucidated by a combination of time-resolved small and wide angle x-ray scattering (SAXS/WAXS) experiments with electron microscopy. The effects of bulk and surface crystallization can clearly be distinguished, and the crystallization kinetics of the bulk phase is characterized. The internal pressure due to structural differences between the crystalline and amorphous phase is measured but the physical cause of this pressure can not unambiguously be attributed. The combined measurements comprise a nearly full characterization of the crystallization processes and the resulting sample morphology.

Microfluidic processing of concentrated surfactant mixtures: online SAXS, microscopy and rheology.

Science.gov (United States)

Martin, Hazel P; Brooks, Nicholas J; Seddon, John M; Luckham, Paul F; Terrill, Nick J; Kowalski, Adam J; Cabral, João T

2016-02-14

We investigate the effect of microfluidic flow on the microstructure and dynamics of a model surfactant mixture, combining synchrotron Small Angle X-ray Scattering (SAXS), microscopy and rheology. A system comprising a single-chain cationic surfactant, hexadecyl trimethyl ammonium chloride (C16TAC), a short-chain alcohol (1-pentanol) and water was selected for the study due to its flow responsiveness and industrial relevance. Model flow fields, including sequential contraction-expansion (extensional) and rotational flows, were investigated and the fluid response in terms of the lamellar d-spacing, orientation and birefringence was monitored in situ, as well as the recovery processes after cessation of flow. Extensional flows are found to result in considerable d-spacing increase (from approx 59 Å to 65 Å). However, under continuous flow, swelling decreases with increasing flow velocity, eventually approaching the equilibrium values at velocities ≃2 cm s(-1). Through individual constrictions we observe the alignment of lamellae along the flow velocity, accompanied by increasing birefringence, followed by an orientation flip whereby lamellae exit perpendicularly to the flow direction. The resulting microstructures are mapped quantitatively onto the flow field in 2D with 200 μm spatial resolution. Rotational flows alone do not result in appreciable changes in lamellar spacing and flow type and magnitude evidently impact the fluid microstructure under flow, as well as upon relaxation. The findings are correlated with rheological properties measured ex situ to provide a mechanistic understanding of the effect of flow imposed by tubular processing units in the phase behavior and performance of a model surfactant system with ubiquitous applications in personal care and coating industries.

Monitoring of the Y2K Outburst of Cyg X-3 with BeppoSAX

Science.gov (United States)

Palazzi, E.; dal Fiume, D.; Amati, L.; del Sordo, S.; Frontera, F.; Masetti, N.; Orlandini, M.; Santangelo, A.; Segreto, A.

2001-09-01

The latest outburst of Cyg X-3, occurred during year 2000, was extensively monitored with the BeppoSAX satellite, which observed the source 6 times at different brightness levels. We here report on these observations, in which the X-ray spectrum appears very complex and strongly evolving as the brightness of the object changes.

Small angle x-ray scattering from proteins in solution

International Nuclear Information System (INIS)

de Souza, C.F.; Torriani, I.L.; Bonafe, C.F.S.; Merrelles, N.C.; Vachette, P.

1989-01-01

In this work the authors report experiments performed with giant respiratory proteins from annelids (erythrocruorins), known to have a molecular weight in the order of four million Daltons. Preliminary x-ray scattering data was obtained using a conventional rotating anode source. High resolution small angle scattering curves were obtained with synchrotron radiation from the DCI storage ring at LURE. Data from solutions with several protein concentrations were analyzed in order to determine low resolution dimensional parameters, using Guinier plots from the smeared scattering curves and the inverse transformation method

O poder das letras: cristianismo e magia no Pater Noster anglo-saxão

Directory of Open Access Journals (Sweden)

Elton Oliveira Souza de Medeiros

2013-05-01

Full Text Available Uma área que vem crescendo nas últimas décadas no campo historiográfico é o estudo sobre as práticas mágicas medievais. Dentro do cenário a ser abordado neste artigo – a Inglaterra anglo-saxônica – há uma documentação substancial de natureza literária, escrita entre os séculos IX e XI, que se revela como uma fonte essencial para o tema em questão. Neste artigo então pretendemos realizar uma análise sobre o uso e a importância das letras e palavras para as práticas mágicas dentro do contexto da cristandade e focando como um exemplo disso o poder do Pater Noster contido no poema em inglês antigo Salomão & Satuno I, que se revela como uma mescla de elementos da tradição cristã greco-romana e das práticas mágicas populares anglo-saxônicas.

Small-angle X-ray scattering on growth of AgCl crystallites in photochromic glasses

Energy Technology Data Exchange (ETDEWEB)

Takatohi, U.E. [Inst. Adventista de Ensino, Sao Paulo (Brazil); Bittencourt, D.R.S.; Watanabe, S.

1997-10-01

Reversible changes in the optical properties of photochromic glasses are observed owing to the presence of small silver halide crystals inside the glassy matrix. These crystals grow during the glass heat-treatment processing. Samples with molar composition of 40SiO{sub 2}.10Al{sub 2}O{sub 3}.16.1K{sub 2}O.33.9B{sub 2}O{sub 3}, doped with AgCl and CuO, were produced and submitted to different heat treatments: (i) for 0.5 h at temperatures from 753 to 893 K and (ii) at 873 K for periods of time from 0.25 to 1.25 h. Small-angle X-ray scattering (SAXS) was used to characterize the samples. The samples heat treated between 843 and 893 K presented an increasing growth rate of the Guinier radius (R{sub g}). Samples heat treated at a fixed temperature of 873 K and different time t showed a law R{sub g}{sup 3} = kt + c. Variations in the optical absorbance at 280 nm and the additional absorbance spectra of samples exposed to light showed correlation with the SAXS results. (orig.). 16 refs.

Insights into the interactions among Surfactin, betaines, and PAM: surface tension, small-angle neutron scattering, and small-angle X-ray scattering study.

Science.gov (United States)

Xiao, Jingwen; Liu, Fang; Garamus, Vasil M; Almásy, László; Handge, Ulrich A; Willumeit, Regine; Mu, Bozhong; Zou, Aihua

2014-04-01

The interactions among neutral polymer polyacrylamide (PAM) and the biosurfactant Surfactin and four betaines, N-dodecyl-N,N-dimethyl-3-ammonio-1-propanesulfonate (SDDAB), N-tetradecyl-N,N-dimethyl-3-ammonio-1-propanesulfonate (STDAB), N-hexadecyl-N,N-dimethyl-3-ammonio-1-propanesulfonate (SHDAB), and N-dodecyl-N,N-dimethyl-2-ammonio-acetate (C12BE), in phosphate buffer solution (PBS) have been studied by surface tension measurements, small-angle neutron scattering (SANS), small-angle X-ray scattering (SAXS), and rheological experiments. It has been confirmed that the length of alkyl chain is a key parameter of interaction between betaines and PAM. Differences in scattering contrast between X-ray and neutrons for surfactants and PAM molecules provide the opportunity to separately follow the changes of structure of PAM and surfactant aggregates. At concentrations of betaines higher than CMC (critical micelle concentration) and C2 (CMC of surfactant with the presence of polymer), spherical micelles are formed in betaines and betaines/PAM solutions. Transition from spherical to rod-like aggregates (micelles) has been observed in solutions of Surfactin and Surfactin/SDDAB (αSurfactin = 0.67 (molar fraction)) with addition of 0.8 wt % of PAM. The conformation change of PAM molecules only can be observed for Surfactin/SDDAB/PAM system. Viscosity values follow the structural changes suggested from scattering measurements i.e., gradually increases for mixtures PAM → Surfactin/PAM → Surfactin/SDDAB/PAM in PBS.

Determination by Small-angle X-ray Scattering of Pore Size Distribution in Nanoporous Track-etched Polycarbonate Membranes

Science.gov (United States)

Jonas, A. M.; Legras, R.; Ferain, E.

1998-03-01

Nanoporous track-etched membranes with narrow pore size distributions and average pore size diameters tunable from 100 to 1000 Åare produced by the chemical etching of latent tracks in polymer films after irradiation by a beam of accelerated heavy ions. Nanoporous membranes are used for highly demanding filtration purposes, or as templates to obtain metallic or polymeric nanowires (L. Piraux et al., Nucl. Instr. Meth. Phys. Res. 1997, B131, 357). Such applications call for developments in nanopore size characterization techniques. In this respect, we report on the characterization by small-angle X-ray scattering (SAXS) of nanopore size distribution (nPSD) in polycarbonate track-etched membranes. The obtention of nPSD requires inverting an ill-conditioned inhomogeneous equation. We present different numerical routes to overcome the amplification of experimental errors in the resulting solutions, including a regularization technique allowing to obtain the nPSD without a priori knowledge of its shape. The effect of deviations from cylindrical pore shape on the resulting distributions are analyzed. Finally, SAXS results are compared to results obtained by electron microscopy and conductometry.

Spectral properties of GRBs observed with BeppoSAX

International Nuclear Information System (INIS)

Costa, E.; Frontera, F.

2003-01-01

The BeppoSAX mission has not only significantly improved the Gamma-Ray Burst science through the discovery of the afterglows but is also providing important data on the prompt events. The Gamma-Ray Burst Monitor is building a catalogue of GRBs that, due to a recently achieved, coarse but suitable positioning capabilities, can usefully integrate and extend the BATSE catalogues. We show the good relative calibration of the two experiments. Wide Field Cameras are providing a sample of about 40 GRBs, in an important band so far relatively ill covered. Moreover the combined use of the two instruments is providing a unique information on the spectral evolution of the GRBs. We show some recent spectral results based on these data and discuss the impact on our knowledge of GRB physics

Small-angle X-ray scattering at high brilliance european synchrotrons for biotechnology and nano-technology

International Nuclear Information System (INIS)

Svergun, D.; Malfois, M.; Svergun, D.; Douka, M.; Riekel, Ch.; Perez, J.; Roessle, M.; Amenitsch, H.; Gunter Grossman, J.; Vestergaard, B.; Receveur-Brechot, V.; Roth, St.V.; Ferrari, E.

2007-01-01

Different issues such as micro-fluidic devices for SAXS (small-angle X-ray diffraction), the use of electro-spray and ion trapping for SAXS in the gas phase, the study of flexible and disordered proteins through SAXS, the time-resolved SAXS studies in solution, or the study of nano-structured soft materials, were addressed in this workshop. This document gathers the transparencies of the presentations

Small-angle X-ray scattering at high brilliance european synchrotrons for biotechnology and nano-technology

Energy Technology Data Exchange (ETDEWEB)

Svergun, D.; Malfois, M. [EMBL c/o DESY, Hamburg (Germany); Svergun, D. [Institute of Crystallography, Russian Academy of Sciences, Moscow (Russian Federation); Douka, M. [Commission Europeenne, DG III, Bruxelles (Belgium); Riekel, Ch. [European Synchrotron Radiation Facility (ESRF), 38 - Grenoble (France); Perez, J. [Soleil, 91 - Saclay (France); Roessle, M. [European Molecular Biology Laboratory (EMBL), 38 - Grenoble (France); Amenitsch, H. [IBN/Elettra (Germany); Gunter Grossman, J. [Daresbury Synchrotron Radiation Source (SRS) (United Kingdom); Vestergaard, B. [University of Pharmaceutical Sciences, Copenhagen (Denmark); Receveur-Brechot, V. [Centre National de la Recherche Scientifique (CNRS/AFMB), 13 - Marseille (France); Roth, St.V. [Deutsches Elektronen Synchrotron (HASYLAB), Hamburg (Germany); Ferrari, E. [National Institute for the Physics of Matter (CNR-INFM), Trieste (Italy)

2007-07-01

Different issues such as micro-fluidic devices for SAXS (small-angle X-ray diffraction), the use of electro-spray and ion trapping for SAXS in the gas phase, the study of flexible and disordered proteins through SAXS, the time-resolved SAXS studies in solution, or the study of nano-structured soft materials, were addressed in this workshop. This document gathers the transparencies of the presentations.

An Alternate Light Curve Solution of AR Lacertae

Directory of Open Access Journals (Sweden)

Hong Suh Park

1984-09-01

Full Text Available Photoelectric UBV light curves of AR Lacertae made in one season during 1981-82 are presented. Although the shape of the light curves in the outside eclipses show a strong distortion, the scatter of observations as well as phase coverage are better than those previously available. Fourier coefficients are derived from the V-light curve and observed curve successfully rectified to the Russell model. Light curve solutions are computed and the geometrical and physical parameters of AR Lac are derived as as = 0.812, ag = 0.341, j = 86°3, Ls = 0.372, Lg = 0.628, k = 0.53, Xs = 0.85, Xg = 0.4.

X-ray scattering evaluation of ultrastructural changes in human dental tissues with thermal treatment.

Science.gov (United States)

Sandholzer, Michael A; Sui, Tan; Korsunsky, Alexander M; Walmsley, Anthony Damien; Lumley, Philip J; Landini, Gabriel

2014-05-01

Micro- and ultrastructural analysis of burned skeletal remains is crucial for obtaining a reliable estimation of cremation temperature. Earlier studies mainly focused on heat-induced changes in bone tissue, while this study extends this research to human dental tissues using a novel quantitative analytical approach. Twelve tooth sections were burned at 400-900°C (30-min exposure, increments of 100°C). Subsequent combined small- and wide-angle X-ray scattering (SAXS/WAXS) experiments were performed at the Diamond Light Source synchrotron facility, where 28 scattering patterns were collected within each tooth section. In comparison with the control sample, an increase in mean crystal thickness was found in burned dentine (2.8-fold) and enamel (1.4-fold), however at a smaller rate than reported earlier for bone tissue (5-10.7-fold). The results provide a structural reference for traditional X-ray scattering methods and emphasize the need to investigate bone and dental tissues separately to obtain a reliable estimation of cremation temperature. © 2014 American Academy of Forensic Sciences.

A small angle X-ray scattering method to investigate the crack tip in metals. Final report of the Marie Curie individual fellowship project

International Nuclear Information System (INIS)

Ouytsel, K. van; Boehmert, J.; Mueller, G.

2003-08-01

Structural materials, such as ferritic and austenitic steels or aluminium alloys used in the nuclear and aircraft industry, are subjected to external operational loads in different environments. Adopting a damage tolerant design principle, understanding the growth of preexisting or newly formed cracks under these conditions is of prime relevance to prevent extensive crack propagation and failure of the component. Within this framework, the characterization of early stages of the damage processes, as nucleation, growth and coalescence of micro-voids and the evolution of the spatial dislocation distribution (dislocation patterning) is a particularly challenging aspect. It was the objective of the work performed to investigate the damage structure near a crack tip by means of small angle X-ray scattering (SAXS). Pre-cracked fracture mechanics standard specimens from different aluminium alloys and steels were loaded up to different amounts of crack growth. From the crack tip range samples of 100 to 200 μm thickness were prepared and a small region around the crack tip was scanned using a microfocused Synchrotron beam. The SAXS experiments were performed at different Synchrotron sources and equipments with different beam cross section, scan step width and X-ray energy. Additionally, the investigation was completed by other methods like X-ray diffraction, X-ray imaging diffraction technique (MAXIM), transmission electron microscopy, scanning electron microscopy, and positron annihilation spectroscopy. The SAXS intensity pattern shows location-related effects. Potential SAXS parameters to characterize the damage are the integral intensity, a fractal dimension parameter and a value determined from the ratio of the intensity vertical and horizontal to the direction of crack growth. Above all, the last parameter is suitable to depict the damage zone around the crack tip. It is robust and applicable even for a material which exhibits an anisotropic SAXS pattern in the

Real time X-ray scattering study of the formation of ZnS nanoparticles using synchrotron radiation

International Nuclear Information System (INIS)

Rath, T.; Novák, J.; Amenitsch, H.; Pein, A.; Maier, E.; Haas, W.; Hofer, F.; Trimmel, G.

2014-01-01

We investigate the growth of ZnS nanoparticles by a real-time simultaneous small and wide angle X-ray scattering (SAXS, WAXS) study using synchrotron radiation. Zinc chloride and elemental sulfur were dissolved in oleylamine. The formation of nanoparticles was induced by heating to 170 °C and 215 °C. The influence of temperature, reaction time, and sulfur concentration was investigated. After a short phase of rapid growth, saturation in size and a slower growth is observed depending on the temperature. The final size of the nanoparticles ranges between 2 and 6 nm for the investigated growth conditions and increases with the reaction temperature and sulfur concentration. SAXS analysis allows for determination of the size of the nanoparticles and proves also the existence of an organized layer of oleylamine molecules covering the nanoparticles' surfaces, which, however, appears only for diameters of the nanoparticles larger than approximately 2.8 nm. The investigation of the measured structure factor of the nanoparticle assemblies showed that the distance of an attractive interaction is 2.5 nm, which was interpreted as a consequence of the ordered oleylamine surface layer. - Highlights: • ZnS nanoparticle growth is investigated by real-time simultaneous SAXS and WAXS measurements. • Nanoparticle growth can be divided into two growth phases. • Higher reaction temperature or higher surplus of sulfur leads to larger nanoparticles. • Post-growth ex situ XRD and TEM measurements confirm results of the in situ study. • Nanoparticles are surrounded by a 2.6 nm thick ordered shell of oleylamine

Small angle neutron scattering

International Nuclear Information System (INIS)

Bernardini, G.; Cherubini, G.; Fioravanti, A.; Olivi, A.

1976-09-01

A method for the analysis of the data derived from neutron small angle scattering measurements has been accomplished in the case of homogeneous particles, starting from the basic theory without making any assumption on the form of particle size distribution function. The experimental scattering curves are interpreted with the aid the computer by means of a proper routine. The parameters obtained are compared with the corresponding ones derived from observations at the transmission electron microscope

The measurements of coexistence curves and light scattering for {xC6H5CN + (1 - x)CH3(CH2)10CH3} in the critical region

International Nuclear Information System (INIS)

Mao Chunfeng; Wang Nong; Peng Xuhong; An Xueqin; Shen Weiguo

2008-01-01

The coexistence curves and light scattering data for a critical solution of (benzonitrile + dodecane) have been reported. The critical exponents relating to the difference in density variables of two coexisting phases β, the correlation length ν, and the osmotic compressibility γ have been determined. The experimental results of the coexistence curves have also been analyzed to examine the Wegner correction terms and the behavior of the diameter of the coexistence curves. The data analysis shows that the 3D-Ising behavior is valid in a temperature range close to the critical point. However, in a wide temperature range the exponential values of ν and γ change with the temperature significantly, clearly exhibiting the critical crossover from the 3D-Ising universality class to the classical one

An empirical formula for scattered neutron components in fast neutron radiography

International Nuclear Information System (INIS)

Dou Haifeng; Tang Bin

2011-01-01

Scattering neutrons are one of the key factors that may affect the images of fast neutron radiography. In this paper, a mathematical model for scattered neutrons is developed on a cylinder sample, and an empirical formula for scattered neutrons is obtained. According to the results given by Monte Carlo methods, the parameters in the empirical formula are obtained with curve fitting, which confirms the logicality of the empirical formula. The curve-fitted parameters of common materials such as 6 LiD are given. (authors)

Batse/Sax and Batse/RXTE-ASM Joint Spectral Studies of GRBs

Science.gov (United States)

Paciesas, William S.

2002-01-01

We proposed to make joint spectral analysis of gamma-ray bursts (GRBs) in the BATSE data base that are located within the fields of view of either the BeppoSAX wide field cameras (WFCs) or the RXTE all-sky monitor (ASM). The very broad-band coverage obtained in this way would facilitate various studies of GRB spectra that are difficult to perform with BATSE data alone. Unfortunately, the termination of the CGRO mission in June 2000 was not anticipated at the time of the proposal, and the sample of common events turned out to be smaller than we would have liked.

Study on the conformal variations of bovine and human serum albumin in solution using small angle X-ray scattering

International Nuclear Information System (INIS)

Olivieri, Johnny Rizzieri.

1992-01-01

It is reported a Small Angle X-Ray Scattering (SAXS) study of BSA (Bovine Serum Albumin) and HSA (Human Serum Albumin) on pH between 2.5 and 7.0. The measured scattering intensities, normalized in relation to incident beam, exposition time and scattering due to solvent and capillary, and corrected due to concentration and beam shape effects, have shown a strong dependence of the protein shape with pH for both albumins. It was found that the radius of gyration varies between 26.7 and 35 A, and the analyses of the distance distribution function. P(r), indicated that these proteins undergoes conformational changes with pH. Different theoretical shapes have been proposed and analysed comparing the computed P(r) function generated from the models with the experimental P(r). A large variety of shapes were found in both proteins, indicating that BSA and HSA are very flexibility macromolecules. (author). 60 refs., 49 figs., 7 tabs

X-ray small angle scattering of polymer solutions

International Nuclear Information System (INIS)

Koyama, Ryuzo

1975-01-01

In recent papers, the calculated results were reported on the angular dependence of the intensity of scattered light or X-ray by chain polymers, on the basis of a stiff chain model. As the results, the curves of S 2 P (theta) corresponding to Kratky plot, for different molecular expansion, showed a plateau, and the height of the plateau was proportional to the inverse of molecular expansion coefficient α 2 . But as seen later, there is some possibility that the assumption made in the calculation overestimated the expansion of small segments which theoretically determines scattering curves at large scattering angles, such as the plateau. Accordingly, modified calculation was carried out by adopting the stiff chain polymer model as the previous case. When the contour length of a chain segment is very long, it can be treated approximately as a Gaussian coil, thus the equation for a chain segment expansion coefficient α (t) was obtained. Then the mean square distance of chain segments of polymer molecules was able to be determined, and the equation for a particle scattering factor P(theta) was obtained. The numerical calculation of P(theta) showed that this modified assumption considerably decreased the effect of molecular expansion on P(theta), and the curves of S 2 P(theta) increased monotonously without showing the plateau. The result of this calculation was compared with the experimental curves of polystyrene-toluene solution, and the agreement better than before was obtained. (Kako, I.)

Analysis of the radial distribution curves of partially ordered condensed carbon films

International Nuclear Information System (INIS)

Palatnik, L.S.; Derevyanchenko, A.S.; Nechitajlo, A.A.; Stetsenko, A.N.; Gorbenko, N.I.

1977-01-01

The Fourier analysis of the electron scattering curves has been carried out to determine the short-range order structure of carbon condensates. The intensity curves for carbon films condensed in a approximately 10 -6 Torr vacuum upon a substrate heated up to 600 deg C were obtained by diffraction techniques with filtration of the inelastic scattered electron background. The radial distribution curve errors were analyzed and quantified with the aid of a computer to determine the short-range order of the condensed carbon. It has been shown that carbon films consist of regions measuring approximately 20 A formed by parallelly packed graphite nets with azimuthal orientation different from that in ideal graphite crystals

Experimental set-up for time resolved small angle X-ray scattering studies of nanoparticles formation using a free-jet micromixer

Energy Technology Data Exchange (ETDEWEB)

Marmiroli, Benedetta [Institute for Biophysics and Nanosystem Research, Austrian Academy of Science, Schmiedlstrasse 6, Graz (Austria); Grenci, Gianluca [TASC INFM/CNR, SS 14 km 163.5, Basovizza, TS (Italy); Cacho-Nerin, Fernando; Sartori, Barbara; Laggner, Peter [Institute for Biophysics and Nanosystem Research, Austrian Academy of Science, Schmiedlstrasse 6, Graz (Austria); Businaro, Luca [TASC INFM/CNR, SS 14 km 163.5, Basovizza, TS (Italy); Amenitsch, Heinz, E-mail: heinz.amenitsch@elettra.trieste.i [Institute for Biophysics and Nanosystem Research, Austrian Academy of Science, Schmiedlstrasse 6, Graz (Austria)

2010-02-15

Recently, we have designed, fabricated and tested a free-jet micromixer for time resolved small angle X-ray scattering (SAXS) studies of nanoparticles formation in the <100 mus time range. The microjet has a diameter of 25 mum and a time of first accessible measurement of 75 mus has been obtained. This result can still be improved. In this communication, we present a method to estimate whether a given chemical or biological reaction can be investigated with the micromixer, and to optimize the beam size for the measurement at the chosen SAXS beamline. Moreover, we describe a system based on stereoscopic imaging which allows the alignment of the jet with the X-ray beam with a precision of 20 mum. The proposed experimental procedures have been successfully employed to observe the formation of calcium carbonate (CaCO{sub 3}) nanoparticles from the reaction of sodium carbonate (Na{sub 2}CO{sub 3}) and calcium chloride (CaCl{sub 2}). The induction time has been estimated in the order of 200 mus and the determined radius of the particles is about 14 nm.

Synchrotron X-ray scattering characterization of the molecular structures of star polystyrenes with varying numbers of arms.

Science.gov (United States)

Jin, Sangwoo; Higashihara, Tomoya; Jin, Kyeong Sik; Yoon, Jinhwan; Rho, Yecheol; Ahn, Byungcheol; Kim, Jehan; Hirao, Akira; Ree, Moonhor

2010-05-20

We have synthesized well-defined multiarmed star polystyrenes, with 6, 9, 17, 33, and 57 arms, and studied their molecular shapes and structural characteristics in a good solvent (tetrahydrofuran at 25 degrees C) and in a theta (Theta) solvent (cyclohexane at 35 degrees C) by small-angle X-ray scattering (SAXS) using a synchrotron radiation source. Analysis of the SAXS data provided a detailed characterization of the molecular shapes, including the contributions of the blob morphology of the arms, the radius of gyration, the paired distance distribution, the radial electron density distribution, and the Zimm-Stockmayer and Roovers g-factor, for the multiarmed star polystyrenes. In particular, the molecular shapes of the star polystyrenes were found to change from a fuzzy ellipsoid, for the 6-armed polystyrene, to a fuzzy sphere, for the 57-armed polystyrene, with an increasing number of arms. The ellipsoidal character of the star polystyrenes with fewer arms may originate from the extended anisotropically branched architecture at the center of the molecule. The arms of the star polystyrenes were found to be more extended than those of the linear polystyrenes. Furthermore, the degree of chain extension in the arms increased with the number of arms.

Soft excess and orbital evolution studies of X-ray pulsars with BeppoSAX

International Nuclear Information System (INIS)

Paul, B.; Naik, S.; Bhatt, N.

2004-01-01

We present here a spectral study of two accreting binary X-ray pulsars LMC X-4 and SMC X-1 made with the BeppoSAX observatory. The energy spectrum of both the pulsars in 0.1-10.0 keV band can be described by a model consisting of a hard power-law component, a soft excess and an iron emission line at 6.4 keV. In addition, the power-law component of SMC X-1 also has an exponential cutoff at ∼ 6 keV. Pulse-phase resolved spectroscopy confirms a pulsating nature of the soft spectral component in both the pulsars, with a certain phase offset compared to the hard power-law component. A dissimilar pulse profile of the two spectral components and a phase difference between the pulsating soft and hard spectral components are evidence for their different origins. In another study of an accreting binary X-ray pulsar Her X-1, we have made accurate measurements of new mid-eclipse times from pulse arrival time delays using observations made with the BeppoSAX and RXTE observatories. The new measurements, combined with the earlier reported mid-eclipse times are used to investigate orbital evolution of the binary. The most recent observation indicates deviation from a quadratic trend coincident with an anomalous low X-ray state, observed for the second time in this pulsar

Fluid adsorption in ordered mesoporous solids determined by in situ small-angle X-ray scattering.

Science.gov (United States)

Findenegg, Gerhard H; Jähnert, Susanne; Müter, Dirk; Prass, Johannes; Paris, Oskar

2010-07-14

The adsorption of two organic fluids (n-pentane and perfluoropentane) in a periodic mesoporous silica material (SBA-15) is investigated by in situ small-angle X-ray scattering (SAXS) using synchrotron radiation. Structural changes are monitored as the ordered and disordered pores in the silica matrix are gradually filled with the fluids. The experiments yield integrated peak intensities from up to ten Bragg reflections from the 2D hexagonal pore lattice, and additionally diffuse scattering contributions arising from disordered (mostly intrawall) porosity. The analysis of the scattering data is based on a separation of these two contributions. Bragg scattering is described by adopting a form factor model for ordered pores of cylindrical symmetry which accounts for the filling of the microporous corona, the formation of a fluid film at the pore walls, and condensation of the fluid in the core. The filling fraction of the disordered intrawall pores is extracted from the diffuse scattering intensity and its dependence on the fluid pressure is analyzed on the basis of a three-phase model. The data analysis introduced here provides an important generalisation of a formalism presented recently (J. Phys. Chem. C, 2009, 13, 15201), which was applicable to contrast-matching fluids only. In this way, the adsorption behaviour of fluids into ordered and disordered pores in periodic mesoporous materials can be analyzed quantitatively irrespective of the fluid density.

Precise small-angle X-ray scattering evaluation of the pore structures in track-etched membranes: Comparison with other convenient evaluation methods

Energy Technology Data Exchange (ETDEWEB)

Miyazaki, Tsukasa, E-mail: t_miyazaki@cross.or.jp [Neutron Science and Technology Center, Comprehensive Research Organization for Science and Society, 162-1, Shirakata, Tokai-mura, Naka-gun, Ibaraki 319-1106 (Japan); Takenaka, Mikihito [Department of Polymer Chemistry, Gradual School of Engineering, Kyoto University, Kyotodaigaku-katsura, Kyoto 615-8510 (Japan)

2017-03-01

Poly(ethylene terephthalate) (PET)-based track-etched membranes (TMs) with pore sizes ranging from few nanometers to approximately 1 μm are used in various applications in the biological field, and their pore structures are determined by small-angle X-ray scattering (SAXS). These TMs with the nanometer-sized cylindrical pores aligned parallel to the film thickness direction are produced by chemical etching of the track in the PET films irradiated by heavy ions with the sodium hydroxide aqueous solution. It is well known that SAXS allows us to precisely and statistically estimate the pore size and the pore size distribution in the TMs by using the form factor of a cylinder with the extremely long pore length relative to the pore diameter. The results obtained were compared with those estimated with scanning electron microscopy and gas permeability measurements. The result showed that the gas permeability measurement is convenient to evaluate the pore size of TMs within a wide length scale, and the SEM observation is also suited to estimate the pore size, although SEM observation is usually limited above approximately 30 nm.

Fatigue and damage tolerance scatter models

Science.gov (United States)

Raikher, Veniamin L.

1994-09-01

Effective Total Fatigue Life and Crack Growth Scatter Models are proposed. The first of them is based on the power form of the Wohler curve, fatigue scatter dependence on mean life value, cycle stress ratio influence on fatigue scatter, and validated description of the mean stress influence on the mean fatigue life. The second uses in addition are fracture mechanics approach, assumption of initial damage existence, and Paris equation. Simple formulas are derived for configurations of models. A preliminary identification of the parameters of the models is fulfilled on the basis of experimental data. Some new and important results for fatigue and crack growth scatter characteristics are obtained.

The Structure of Urease Activation Complexes Examined by Flexibility Analysis, Mutagenesis, and Small-angle X-ray Scattering Approaches

International Nuclear Information System (INIS)

Quiroz, Soledad; Sukuru, Sai Chetan K.; Hausinger, Robert P.; Kuhn, Leslie A.; Heller, William T

2008-01-01

Conformational changes of Klebsiella aerogenes urease apoprotein (UreABC) 3 induced upon binding of the UreD and UreF accessory proteins were examined by a combination of flexibility analysis, mutagenesis, and small-angle X-ray scattering (SAXS). ProFlex analysis of urease provided evidence that the major domain of UreB can move in a hinge-like motion to account for prior chemical cross-linking results. Rigidification of the UreB hinge region, accomplished through a G11P mutation, reduced the extent of urease activation, in part by decreasing the nickel content of the mutant enzyme, and by sequestering a portion of the urease apoprotein in a novel activation complex that includes all of the accessory proteins. SAXS analyses of urease, (UreABC-UreD) 3 , and (UreABC-UreDF) 3 confirm that UreD and UreF bind near UreB at the periphery of the (UreAC) 3 structure. This study supports an activation model in which a domain-shifted UreB conformation in (UreABC-UreDF) 3 allows CO 2 and nickel ions to gain access to the nascent active site

Pion deuteron scattering at intermediate energies

International Nuclear Information System (INIS)

Ferreira, E.M.

1978-09-01

A comparison is made of results of calculations of πd elastic scattering cross section using multiple scattering and three-body equations, in relation to their ability to reproduce the experimental data at intermediate energies. It is shown that the two methods of theoretical calculation give quite similar curves for the elastic differential cross sections, and that both fail in reproducing backward scattering data above 200MeV. The new accurate experimental data on πd total cross section as a function of the energy are confronted with the theoretical values obtained from the multiple scattering calculation through the optical theorem. Comparison is made between the values of the real part of the forward amplitude evaluated using dispersion relations and using the multiple scattering method [pt

Synchrotron small-angle x-ray scattering investigation on integral membrane protein light-harvesting complex LH2 from photosynthetic bacterium rhodopseudomonas acidophila

International Nuclear Information System (INIS)

Du Luchao; Weng Yuxiang; Hong Xinguo; Xian Dingchang; Kobayashi Katsumi

2006-01-01

Structures of membrane protein in solution are different from that in crystal phase. We present the primary results of small angle x-ray scattering (SAXS) resolved topological structures of a light harvesting antenna membrane protein complex LH2 from photosynthetic bacteria Rhodopseudomonas acidophila in detergent solution for the first time. Our results show that the elliptical shape of the LH2 complex in solution clearly deviates from its circular structure in crystal phase determined by x-ray diffraction. This result provides an insight into the structure and function interplay in LH2. (authors)

Assessment of Escherichia coli selenophosphate synthetase oligomeric states by analytical ultracentrifugation and small angle X-ray scattering

Energy Technology Data Exchange (ETDEWEB)

Silva, I.R.; Faim, F.M.; Oliveira Neto, M.; Thiemann, O.H. [Universidade de Sao Paulo (USP-SC), Sao Carlos, SP (Brazil); Borges, J.C. [Universidade de Sao Paulo (IQSC/USP), Sao Carlos, SP (Brazil). Inst. de Quimica

2012-07-01

Full text: Selenium is an essential micronutrient for many organisms and is present in selenium-containing proteins as selenocysteine (Sec) and RNAs as selenouridine. Specific selenium incorporation into selenoproteins and RNAs requires the generation of a biologically active selenium donor compound, selenophosphate, which is produced from the activation of selenide with adenosine 5-triphosphate (ATP) in a reaction catalyzed by Selenophosphate Synthetase (SELD). Therefore, SELD is a key enzyme of the selenium pathway in the cell. The Escherichia coli SELD open reading frame was cloned into pET28a (Novagen) expression vector and the recombinant protein was over expressed in Escherichia coli BL21(DE3) strain. In order to purify the protein, we used metal-chelate affinity chromatography followed by a gel filtration step. Analytical Ultracentrifugation (AUC) and Small Angle X-ray Scattering (SAXS) were employed to study the oligomeric states of the soluble protein. The results of AUC revealed dimer-tetramer and tetramer-octamer equilibrium at low concentrations of protein, with dissociation constants of 70 2 and 560 40 M, respectively. Moreover, the SAXS results pointed the oligomeric state of the protein at higher concentrations as predominantly dimeric and the p(r) and the SAXS envelope revealed the SELD as elongated. We also performed initial crystallization trials with protein samples at 7 mg/ml in 96-well sitting-drop crystallization plates at room temperature using a crystallization robot. Needle crystals appeared after some days. X-ray diffraction for these crystals were tested in the MX2 beamline at the Brazilian Synchrotron Laboratory (LNLS Campinas). We are now working to improve these crystals in order to obtain suitable crystals for structure determination. (author)

Structure development during isothermal crystallisation of high-density polyethylene: Synchrotron small-angle X-ray scattering study

International Nuclear Information System (INIS)

Ślusarczyk, Czesław

2013-01-01

Isothermal melt crystallisation in high-density polyethylene (HDPE) was studied using the time-resolved SAXS method with synchrotron radiation over a wide range of crystallisation temperatures. The SAXS profile was analysed by an interface distribution function, g 1 (r), which is a superposition of three contributions associated with the size distributions of crystalline (L C ) and amorphous (L A ) layers and a distribution of long period (LP). The morphological parameters extracted from the g 1 (r) functions show that the lamellar thickness increases with time, obeying a logarithmic time dependence. The time evolution of L C observed for the sample crystallised at 122 °C leads to the conclusion that crystallisation proceeds according to the mechanism of thickening growth. For samples crystallised at lower temperatures (116 °C and 118 °C), the lamellar thickening mechanism has been observed. The rate of lamellar thickening in these cases is much lower than that at 122 °C. At 40 °C, thickening of the crystalline layer does not occur. The interface distribution functions were deconvoluted, and the relative standard deviation σ C /L C obtained in this way is an additional parameter that is varied during crystallisation and can be used for analysis of this process. Time-dependent changes in the σ C /L C at large supercooling (T C =40 °C) indicates that L C presents a broad distribution in which the relative standard deviation increases with time. At lower supercooling (T C =122 °C), L C shows a much sharper distribution. In this case, the relative standard deviation decreases with time. - Highlights: • Isothermal melt crystallisation of high-density polyethylene (HDPE) was studied by time-resolved synchrotron small-angle X-ray scattering (SAXS) over a wide-range of supercoolings. • The SAXS profile was analysed by an interface distribution, g 1 (r), function. • At large supercooling (40 °C) the thickening of the crystalline layer does not occur. At

Performance and scientific results of the BeppoSAX Gamma-Ray Burst Monitor

International Nuclear Information System (INIS)

Feroci, M.; Costa, E.; Cinti, M. N.; Frontera, F.; Dal Fiume, D.; Nicastro, L.; Orlandini, M.; Palazzi, E.; Amati, L.; Zavattini, G.; Coletta, A.

1998-01-01

The Italian-Dutch satellite for X-ray Astronomy BeppoSAX is successfully operating on a 600 km equatorial orbit since May 1996. We present here the in-flight performance of the Gamma Ray Burst Monitor (GRBM) experiment during its first year of operation. The GRBM is performing very well, providing an amount of data on GRBs, some of which confirmed by other experiments onboard satellites. It also joined the 3rd Interplanetary Network as a new near-earth node. Important results have been obtained for GRBs (e.g. GRB970228) simultaneously detected in the Wide Field Cameras onboard the same satellite

Small angle scattering study of the structure and organization of RNA and protein in Brome Mosaic Virus (BMV)

Science.gov (United States)

Das, Narayan C.; Warren, Garfield T.; Cheng, Si; Kao, C. Cheng; Ni, Peng; Dragnea, Bogdan; Sokol, Paul E.

2012-02-01

Brome mosaic virus (BMV) is a small icosahedral of the alpha virus-like superfamily of RNA with a segmented positive-strand RNA genome and a mean diameter ˜ 268å that offers high levels of RNA synthesis and virus production in plants. BMV also tightly regulates the packaging of its four RNAs (RNA1 through RNA4) into three separate particles; RNA1 and RNA2 are encapsidated separately while one copy each of RNA3 and RNA4 are normally packaged together. Small angle neutron scattering (SANS) and small angle X-ray scattering (SAXS) were applied to study the size, shape and protein-RNA organization of BMV. D2O/H2O mixture was used to enhance contrast in SANS measurement. The radial distribution of BMV from the Fourier transform of scattering spectrum gives a clear indication of RNA packing, and distribution and their structure in the BMV. The result reveals that the virus is about 266 å in diameter and is composed of RNA inside the virion coated with a protein shell.

Critical behaviour of binary mixture of {xC6H5CN + (1 - x)CH3(CH2)7CH3}: Measurements of coexistence curves, light scattering, and heat capacity

International Nuclear Information System (INIS)

Lei Yuntao; Chen Zhiyun; Wang Nong; Mao Chunfeng; An Xueqin; Shen Weiguo

2010-01-01

Liquid + liquid coexistence, light scattering, and isobaric heat capacity per unit volume for the critical solutions of (benzonitrile + n-nonane) have been measured. The critical exponents relating to the coexistence curve β, the osmotic compressibility γ, the correlation length ν, and the heat capacity α have been deduced and the values are consistent with the 3D-Ising values in the range close to the critical point. The experimental results of the liquid + liquid coexistence were analyzed to examine the Wegner correction terms and the behaviour of the diameter of the coexistence curves. The light scattering data were well described by the crossover model proposed by Anisimov and Sengers, and showed a tendency of monotonic crossover of the critical exponents γ and ν from the 3D-Ising values to the mean-field values as the temperature departures from the critical point. From calorimetric measurements, the amplitude A ± and the critical background B cr of the heat capacity in the critical region have been deduced and some universal ratios are tested.

HPMA-based drug delivery system and its interactions of human serum albumin: SAXS, ITC, and NMR study

Czech Academy of Sciences Publication Activity Database

Filippov, Sergey K.; Kaberov, Leonid; Zhang, X.; Niebuur, B.-J.; Chytil, Petr; Etrych, Tomáš; Wieland, F.; Velychkivska, Nadiia; Starovoytova, Larisa; Svergun, D.; Papadakis, C.

2017-01-01

Roč. 254, 20 August (2017), s. 455 ISSN 0065-7727. [ACS National Meeting & Exposition /254./. 20.08.2017-24.08.2017, Washington] R&D Projects: GA ČR(CZ) GC15-10527J Institutional support: RVO:61389013 Keywords : HPMA * human serum albumin * SAXS Subject RIV: CF - Physical ; Theoretical Chemistry OBOR OECD: Physical chemistry

MAXI/GSC detection of a new outburst from SAX J1810.8-2609

Science.gov (United States)

Negoro, H.; Mihara, T.; Nakahira, S.; Yatabe, F.; Takao, Y.; Matsuoka, M.; Kawai, N.; Sugizaki, M.; Tachibana, Y.; Morita, K.; Sakamoto, T.; Serino, M.; Sugita, S.; Kawakubo, Y.; Hashimoto, T.; Yoshida, A.; Nakajima, M.; Sakamaki, A.; Maruyama, W.; Ueno, S.; Tomida, H.; Ishikawa, M.; Sugawara, Y.; Isobe, N.; Shimomukai, R.; Ueda, Y.; Tanimoto, A.; Morita, T.; Yamada, S.; Tsuboi, Y.; Iwakiri, W.; Sasaki, R.; Kawai, H.; Sato, T.; Tsunemi, H.; Yoneyama, T.; Yamauchi, M.; Hidaka, K.; Iwahori, S.; Kawamuro, T.; Yamaoka, K.; Shidatsu, M.

2018-05-01

We report a new X-ray outburst from the low-mass X-ray binary SAX J1810.8-2609 (aka V4722 Sgr; Ubertini et al. 1998, IAUC 6838) observed with MAXI/GSC. The enhancement was recognized from 2018 April 23 (MJD 58231), and X-ray count rates in the 2-4 keV and 4-10 keV bands peaked on April 26 at 0.085 +/- 0.008 c/s/cm2 ( 80 mCrab) and 0.096+/-0.008 c/s/cm2 ( 82 mCrab), respectively.

Biological Small Angle Scattering: Techniques, Strategies and Tips

Energy Technology Data Exchange (ETDEWEB)

Chaudhuri, Barnali [University at Buffalo (SUNY); Muñoz, Inés G. [Centro Nacional de Investigaciones Oncológicas Madrid, Madrid, Spain; Urban, Volker S. [ORNL; Qian, Shuo [ORNL

2017-12-01

This book provides a clear, comprehensible and up-to-date description of how Small Angle Scattering (SAS) can help structural biology researchers. SAS is an efficient technique that offers structural information on how biological macromolecules behave in solution. SAS provides distinct and complementary data for integrative structural biology approaches in combination with other widely used probes, such as X-ray crystallography, Nuclear magnetic resonance, Mass spectrometry and Cryo-electron Microscopy. The development of brilliant synchrotron small-angle X-ray scattering (SAXS) beam lines has increased the number of researchers interested in solution scattering. SAS is especially useful for studying conformational changes in proteins, highly flexible proteins, and intrinsically disordered proteins. Small-angle neutron scattering (SANS) with neutron contrast variation is ideally suited for studying multi-component assemblies as well as membrane proteins that are stabilized in surfactant micelles or vesicles. SAS is also used for studying dynamic processes of protein fibrillation in amyloid diseases, and pharmaceutical drug delivery. The combination with size-exclusion chromatography further increases the range of SAS applications.The book is written by leading experts in solution SAS methodologies. The principles and theoretical background of various SAS techniques are included, along with practical aspects that range from sample preparation to data presentation for publication. Topics covered include techniques for improving data quality and analysis, as well as different scientific applications of SAS. With abundant illustrations and practical tips, we hope the clear explanations of the principles and the reviews on the latest progresses will serve as a guide through all aspects of biological solution SAS.The scope of this book is particularly relevant for structural biology researchers who are new to SAS. Advanced users of the technique will find it helpful for

Revealing the compact structure of lactic acid bacterial hetero-exopolysaccharides by SAXS and DLS

DEFF Research Database (Denmark)

Khan, Sanaullah; Birch, Johnny; Harris, Pernille

2017-01-01

solution structures of three lactic acid bacterial hetero-exopolysaccharides (HePS-1, HePS-2 and HePS-3). Values of radius of gyration RG, cross-sectional radius of gyration RXS, approximate length L and hydrodynamic diameter were not directly proportional to the molar mass and indicated the HePSs adopted...... Galf residues significantly influence the conformation. Ab initio scattering modeling of HePS-2 and HePS-3 gave excellent curve fittings with χ2 of 0.43 and 0.34 for best-fit models, respectively, compatible with coil-like conformation. The findings disclose solution behaviour of HePS relevant...

Estimation of degree of polymerization of poly-acrylonitrile-grafted carbon nanotubes using Guinier plot of small angle x-ray scattering.

Science.gov (United States)

Cho, Hyunjung; Jin, Kyeong Sik; Lee, Jaegeun; Lee, Kun-Hong

2018-07-06

Small angle x-ray scattering (SAXS) was used to estimate the degree of polymerization of polymer-grafted carbon nanotubes (CNTs) synthesized using a 'grafting from' method. This analysis characterizes the grafted polymer chains without cleaving them from CNTs, and provides reliable data that can complement conventional methods such as thermogravimetric analysis or transmittance electron microscopy. Acrylonitrile was polymerized from the surface of the CNTs by using redox initiation to produce poly-acrylonitrile-grafted CNTs (PAN-CNTs). Polymerization time and the initiation rate were varied to control the degree of polymerization. Radius of gyration (R g ) of PAN-CNTs was determined using the Guinier plot obtained from SAXS solution analysis. The results showed consistent values according to the polymerization condition, up to a maximum R g  = 125.70 Å whereas that of pristine CNTs was 99.23 Å. The dispersibility of PAN-CNTs in N,N-dimethylformamide was tested using ultraviolet-visible-near infrared spectroscopy and was confirmed to increase as the degree of polymerization increased. This analysis will be helpful to estimate the degree of polymerization of any polymer-grafted CNTs synthesized using the 'grafting from' method and to fabricate polymer/CNT composite materials.

Assessment of data-assisted prediction by inclusion of crosslinking/mass-spectrometry and small angle X-ray scattering data in the 12th Critical Assessment of protein Structure Prediction experiment.

Science.gov (United States)

Tamò, Giorgio E; Abriata, Luciano A; Fonti, Giulia; Dal Peraro, Matteo

2018-03-01

Integrative modeling approaches attempt to combine experiments and computation to derive structure-function relationships in complex molecular assemblies. Despite their importance for the advancement of life sciences, benchmarking of existing methodologies is rather poor. The 12 th round of the Critical Assessment of protein Structure Prediction (CASP) offered a unique niche to benchmark data and methods from two kinds of experiments often used in integrative modeling, namely residue-residue contacts obtained through crosslinking/mass-spectrometry (CLMS), and small-angle X-ray scattering (SAXS) experiments. Upon assessment of the models submitted by predictors for 3 targets assisted by CLMS data and 11 targets by SAXS data, we observed no significant improvement when compared to the best data-blind models, although most predictors did improve relative to their own data-blind predictions. Only for target Tx892 of the CLMS-assisted category and for target Ts947 of the SAXS-assisted category, there was a net, albeit mild, improvement relative to the best data-blind predictions. We discuss here possible reasons for the relatively poor success, which point rather to inconsistencies in the data sources rather than in the methods, to which a few groups were less sensitive. We conclude with suggestions that could improve the potential of data integration in future CASP rounds in terms of experimental data production, methods development, data management and prediction assessment. © 2017 Wiley Periodicals, Inc.

Convergence of the multiple scattering expansion in XAFS and XANES

International Nuclear Information System (INIS)

Rehr, J.J.

1992-01-01

The convergence of the multiple-scattering expansion of XAFS and XANES by explicit path-bypath calculations. The approach is based on the fast scattering matrix formalism of Rehr and Albers, together with an automated path finder and filters that exclude negligible paths. High-order scattering terms are found to be essential, especially at low energies. Several factors including the magnitude of curved wave scattering amplitudes, inelastic losses and multiple-scattering Debye-Waller factors control convergence of the expansion. The convergence is illustrated explicitly for the case of diatomic molecules

PREFACE Proceedings of the XIV International Conference on Small-Angle Scattering, SAS-2009

Science.gov (United States)

King, Stephen; Terrill, Nicholas

2010-10-01

The XIV International Conference on Small-Angle Scattering, SAS-2009, was held in Oxford UK, 13-18 September 2009, and was jointly organised under the auspices of the International Union of Crystallography Commission on SAS by a team from the Diamond Light Source and the ISIS Pulsed Neutron Source - their first such joint venture - with help from the UK Science and Technology Facilities Council. It was the first time that this long running and successful series of conferences on the application, science and technology of small-angle scattering techniques had been staged in the UK. The UK has a proud heritage in small-angle scattering: as home to one of the world's first SANS instruments (at AERE Harwell), as the site of the world's first 2nd generation X-ray Synchrotron (the SRS at Daresbury with its suite of SAXS beamlines), and latterly as the location of the world's most successful pulsed source SANS instrument. Indeed, 2009 also marked the 25th Anniversary of neutron operations at ISIS and the opening of a Second Target Station. Whilst the SRS ceased operations in 2008, its mantle has been inherited by the Diamond synchrotron. Many delegates took the opportunity to visit both Diamond and ISIS during a conference excursion. Despite the prevailing global economic downturn, we were delighted that 434 delegates from 32 different countries were able to attend SAS-2009; two-thirds were drawn from the UK, Germany, Japan, the USA and France, but there were also sizeable contingents from Australia, Korea, Taiwan and South America. In many ways this geographical spread reflects the present and emerging distribution, respectively, of 3rd generation X-ray synchrotrons and high-flux neutron sources, although the scope of the conference was not solely limited to these probes. Financial support from the IUCr enabled us to grant bursaries to attend SAS-2009 to 12 delegates from emerging countries (Algeria, Argentina, Brazil, India, Nepal, Romania, Russia and the Ukraine). The

Structural Properties of Pure Simple Alcohols from Ethanol, Propanol, Butanol, Pentanol, to Hexanol: Comparing Monte Carlo Simulations with Experimental SAXS Data

Czech Academy of Sciences Publication Activity Database

Tomšič, M.; Jamnik, A.; Fritz-Popovski, G.; Glatter, O.; Vlček, Lukáš

2007-01-01

Roč. 111, č. 7 (2007), s. 1738-1751 ISSN 1520-6106 Institutional research plan: CEZ:AV0Z40720504 Keywords : alcohols * saxs * monte carlo Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 4.086, year: 2007

The effect of scattered light sensor orientation on roughness measurement of curved polished surfaces

DEFF Research Database (Denmark)

Pilny, Lukas; Bissacco, Giuliano; De Chiffre, Leonardo

directions, and its acquisition within ± 16º angular range with a linear detector array. From the distribution of the acquired scattered light intensity, a number of statistical parameters describing the surface texture are calculated, where the Aq parameter (variance of the scattered light distribution...

INTEGRAL finds renewed X-ray activity of the Neutron star X-ray transient SAX J1750.8-2900

DEFF Research Database (Denmark)

Sanchez-Fernandez, Celia; Chenevez, Jérôme; Kuulkers, Erik

2015-01-01

INTEGRAL Galactic bulge monitoring observations (ATel #438) on UT 13 September 2015 18:50-22:32 reveal renewed X-ray activity from the low-mass X-ray binary transient and Type I X-ray burster SAX J1750.8-2900 (IAU Circ. #6597). The last outburst from this source was reported in 2011 (ATels #3170,...

SuperAGILE detects an X-ray burst from SAX J1750.8-2900

Science.gov (United States)

Pacciani, L.; Costa, E.; Del Monte, E.; Donnarumma, I.; Evangelista, Y.; Feroci, M.; Lapshov, I.; Lazzarotto, F.; Rapisarda, M.; Soffitta, P.; Argan, A.; Trois, A.; Tavani, M.; Piano, G.; Pucella, G.; D'Ammando, F.; Vittorini, V.; Bulgarelli, A.; Gianotti, F.; Trifoglio, M.; Di Cocco, G.; Labanti, C.; Fuschino, F.; Marisaldi, M.; Galli, M.; Chen, A.; Vercellone, S.; Giuliani, A.; Mereghetti, S.; Perotti, F.; Fornari, F.; Fiorini, M.; Caraveo, P.; Pellizzoni, A.; Barbiellini, G.; Longo, F.; Vallazza, E.; Picozza, P.; Morselli, A.; Prest, M.; Lipari, P.; Zanello, D.; Rappoldi, A.; Pittori, C.; Verrecchia, F.; Santolamazza, P.; Preger, B.; Giommi, P.; Salotti, L.

2008-10-01

While pointing at the Galactic Center region, SuperAGILE detected an X-ray burst from a position consistent with the neutron star transient SAX J1750.8-2900. This source was recently reported by Linares et al. (ATel #1662) as returning to a quiescent state, based on a Swift/XRT observation on August 14th 2008 (ATel #1662), after a long outburst started on March 2008 (Markwardt & Swank, ATel #1425), during which also SuperAGILE detected the source at hard X-rays at a flux level of about 80 mCrab (Pacciani et al., ATel #1428).

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

Energy Technology Data Exchange (ETDEWEB)

Wells, Hannah C.; Sizeland, Katie H.; Kayed, Hanan R.; Haverkamp, Richard G., E-mail: r.haverkamp@massey.ac.nz [School of Engineering and Advanced Technology, Massey University, Private Bag 11222, Palmerston North 4442 (New Zealand); Kirby, Nigel; Hawley, Adrian; Mudie, Stephen T. [Australian Synchrotron, 800 Blackburn Road, Clayton, Victoria 3168 (Australia)

2015-01-28

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.

EDITORIAL Proceedings of the XIV International Conference on Small-Angle Scattering, SAS-2009

Science.gov (United States)

Ungar, Goran; Heenan, Richard

2010-10-01

There are 52 papers in these Proceedings. The papers are divided into 10 thematic sections and a section for invited papers and reviews. The sections and the respective section editors are given below. Section Editor(s) Invited Papers and Reviews Peter Griffiths, Wim Bras, Rudolf Winter Beamlines and Instrumentation Elliot Gilbert, Wim Bras, Nigel Rhodes Theory, Data processing and Modelling Jan Skov Pedersen, Carlo Knupp Biological Systems and Membranes Richard Heenan, Cameron Neylon Ceramics, Glasses and Porous Materials Rudolf Winter Colloids and Solutions Peter Griffiths Hierarchical Structures and Fibres Steve Eichhorn, Karen Edler Metallic and Magnetic Systems Armin Hoell Polymers Patrick Fairclough Time resolved Diffraction, Kinetic and Dynamical Studies João Cabral, Christoph Rau We are grateful to all section editors and the many anonymous referees for their invaluable effort which made the publication of the Proceedings possible. The refereeing process was strict and thorough, some papers were rejected and most were improved. The resulting compendium gives a good overview of recent developments in small-angle X-ray and neutron scattering theory, application, methods of analysis and instrumentation. Thus it should be a useful source of reference for a number of years to come. The papers are a good reflection of the material presented at the meeting. Because of the general high quality of the articles, it was difficult to decide which to highlight and be fair to all contributors. The following in particular have caught the attention of the editors. Highlighted papers A statistical survey of publications reporting the application of SAXS and SANS by Aldo Craievich (paper 012003) is recommended reading for anyone needing convincing about the vibrancy of this scientific field and the ever expanding use of these techniques. Two aspects of coherent X-ray scattering, made available by the advent of the 3rd generation synchrotron sources, are discussed in the

Scattered radiation from applicators in clinical electron beams

International Nuclear Information System (INIS)

Battum, L J van; Zee, W van der; Huizenga, H

2003-01-01

In radiotherapy with high-energy (4-25 MeV) electron beams, scattered radiation from the electron applicator influences the dose distribution in the patient. In most currently available treatment planning systems for radiotherapy this component is not explicitly included and handled only by a slight change of the intensity of the primary beam. The scattered radiation from an applicator changes with the field size and distance from the applicator. The amount of scattered radiation is dependent on the applicator design and on the formation of the electron beam in the treatment head. Electron applicators currently applied in most treatment machines are essentially a set of diaphragms, but still do produce scattered radiation. This paper investigates the present level of scattered dose from electron applicators, and as such provides an extensive set of measured data. The data provided could for instance serve as example input data or benchmark data for advanced treatment planning algorithms which employ a parametrized initial phase space to characterize the clinical electron beam. Central axis depth dose curves of the electron beams have been measured with and without applicators in place, for various applicator sizes and energies, for a Siemens Primus, a Varian 2300 C/D and an Elekta SLi accelerator. Scattered radiation generated by the applicator has been found by subtraction of the central axis depth dose curves, obtained with and without applicator. Scattered radiation from Siemens, Varian and Elekta electron applicators is still significant and cannot be neglected in advanced treatment planning. Scattered radiation at the surface of a water phantom can be as high as 12%. Scattered radiation decreases almost linearly with depth. Scattered radiation from Varian applicators shows clear dependence on beam energy. The Elekta applicators produce less scattered radiation than those of Varian and Siemens, but feature a higher effective angular variance. The scattered

INTEGRAL detects an X-ray burst from SAX J1747.0-2853 with no detectable persistent emission

DEFF Research Database (Denmark)

Chenevez, Jérôme; Brandt, Søren Kristian; Kuulkers, Erik

2009-01-01

A new season of observations for the INTEGRAL Galactic Bulge monitoring (see ATel #438) has started on 2009 Feb. 21st. During the latest observation between 2009 Feb 25 13:21 and 17:02 (UT) a type I X-ray burst from SAX J1747.0-2853 (1A 1743-288, aka GX .2-0.2) was detected by JEM-X at UT 14:50:5...

The micro-optic photovoltaic behavior of solar cell along with microlens curved glass substrate

International Nuclear Information System (INIS)

Xie, Jin; Wu, Keke; Cheng, Jian; Li, Ping; Zheng, Jiahua

2015-01-01

Highlights: • A microlens array may be micro-ground on curved photovoltaic glass substrate. • Its micro-optical structure absorbs and scatters the inclined light to solar cell. • It increases conversion efficiency and fill factor in weak and inclined lights. • It improves electricity generation by about 4 times in scattered cloudy daylight. • It produces stronger electricity generation in cloudy day than in sunny day. - Abstract: A hybrid of microlens structure and curved surface may produce high value-added micro-optic performance. Hence, the microlens array is proposed on macro curved glass substrate of thin film solar cell. The objective is to understand how the micro-optic behavior of microlens curved array influences indoor power conversion efficiency and outdoor electricity generation. First, the absorptivities of visible light and infrared light were analyzed in connection with the curved microlens sizes; then the microlens curved glass substrate was fabricated by a Computer Numerical Control (CNC) micro-grinding with micro diamond wheel V-tip; finally, its photovoltaic properties and electricity generation were measured, respectively. It is shown that the microlens curved surface may strongly absorb and scatter light to solar cell. It increases the absorptivity of visible light against plane surface, but it decreases the one of infrared light against microlens surface. When it is applied to solar cell, it enhances the power conversion efficiency by 3.4–10.6% under oblique illumination. When it is applied to solar device, it increases the electricity generation of daylight by 119–106% against microlens surface and by 260–419% against traditional plane surface, respectively. The surprising finding is that it produces much larger electricity generation during cloudy day than during sunny day, but traditional plane surface does not so

Structural analysis of the yeast exosome Rrp6p–Rrp47p complex by small-angle X-ray scattering

Energy Technology Data Exchange (ETDEWEB)

Dedic, Emil; Seweryn, Paulina; Jonstrup, Anette Thyssen; Flygaard, Rasmus Koch [Centre for mRNP Biogenesis and Metabolism, Gustav Wieds Vej 10c, Aarhus University, DK-8000 Aarhus C (Denmark); Department of Molecular Biology and Genetics, Gustav Wieds Vej 10c, Aarhus University, DK-8000 Aarhus C (Denmark); Fedosova, Natalya U. [Department of Biomedicine, Ole Worms Allé 6, Aarhus University, DK-8000 Aarhus C (Denmark); Hoffmann, Søren Vrønning [Institute for Storage Ring Facilities (ISA), Department of Physics and Astronomy, Ny Munkegade 120, Aarhus University, DK-8000 Aarhus C (Denmark); Boesen, Thomas [Centre for Membrane Pumps in Cells and Disease – PUMPKIN, Gustav Wieds Vej 10c, Aarhus University, DK-8000 Aarhus C (Denmark); Department of Molecular Biology and Genetics, Gustav Wieds Vej 10c, Aarhus University, DK-8000 Aarhus C (Denmark); Brodersen, Ditlev Egeskov, E-mail: deb@mb.au.dk [Centre for mRNP Biogenesis and Metabolism, Gustav Wieds Vej 10c, Aarhus University, DK-8000 Aarhus C (Denmark); Department of Molecular Biology and Genetics, Gustav Wieds Vej 10c, Aarhus University, DK-8000 Aarhus C (Denmark)

2014-07-18

Highlights: • We show that S. cerevisiae Rrp6p and Rrp47p stabilise each other in vitro. • We determine molecular envelopes of the Rrp6p–Rrp47p complex by SAXS. • Rrp47p binds at the top of the Rrp6p exonuclease domain. • Rrp47p modulates the activity of Rrp6p on a variety of RNA substrates. • Rrp47p does not affect RNA affinity by Rrp6p. - Abstract: The RNase D-type 3′–5′ exonuclease Rrp6p from Saccharomyces cerevisiae is a nuclear-specific cofactor of the RNA exosome and associates in vivo with Rrp47p (Lrp1p). Here, we show using biochemistry and small-angle X-ray scattering (SAXS) that Rrp6p and Rrp47p associate into a stable, heterodimeric complex with an elongated shape consistent with binding of Rrp47p to the nuclease domain and opposite of the HRDC domain of Rrp6p. Rrp47p reduces the exonucleolytic activity of Rrp6p on both single-stranded and structured RNA substrates without significantly altering the affinity towards RNA or the ability of Rrp6p to degrade RNA secondary structure.

Structural analysis of the yeast exosome Rrp6p–Rrp47p complex by small-angle X-ray scattering

International Nuclear Information System (INIS)

Dedic, Emil; Seweryn, Paulina; Jonstrup, Anette Thyssen; Flygaard, Rasmus Koch; Fedosova, Natalya U.; Hoffmann, Søren Vrønning; Boesen, Thomas; Brodersen, Ditlev Egeskov

2014-01-01

Highlights: • We show that S. cerevisiae Rrp6p and Rrp47p stabilise each other in vitro. • We determine molecular envelopes of the Rrp6p–Rrp47p complex by SAXS. • Rrp47p binds at the top of the Rrp6p exonuclease domain. • Rrp47p modulates the activity of Rrp6p on a variety of RNA substrates. • Rrp47p does not affect RNA affinity by Rrp6p. - Abstract: The RNase D-type 3′–5′ exonuclease Rrp6p from Saccharomyces cerevisiae is a nuclear-specific cofactor of the RNA exosome and associates in vivo with Rrp47p (Lrp1p). Here, we show using biochemistry and small-angle X-ray scattering (SAXS) that Rrp6p and Rrp47p associate into a stable, heterodimeric complex with an elongated shape consistent with binding of Rrp47p to the nuclease domain and opposite of the HRDC domain of Rrp6p. Rrp47p reduces the exonucleolytic activity of Rrp6p on both single-stranded and structured RNA substrates without significantly altering the affinity towards RNA or the ability of Rrp6p to degrade RNA secondary structure

Neutron Scattering in Hydrogenous Moderators, Studied by Time Dependent Reaction Rate Method

Energy Technology Data Exchange (ETDEWEB)

Larsson, L G; Moeller, E; Purohit, S N

1966-03-15

The moderation and absorption of a neutron burst in water, poisoned with the non-1/v absorbers cadmium and gadolinium, has been followed on the time scale by multigroup calculations, using scattering kernels for the proton gas and the Nelkin model. The time dependent reaction rate curves for each absorber display clear differences for the two models, and the separation between the curves does not depend much on the absorber concentration. An experimental method for the measurement of infinite medium reaction rate curves in a limited geometry has been investigated. This method makes the measurement of the time dependent reaction rate generally useful for thermalization studies in a small geometry of a liquid hydrogenous moderator, provided that the experiment is coupled to programs for the calculation of scattering kernels and time dependent neutron spectra. Good agreement has been found between the reaction rate curve, measured with cadmium in water, and a calculated curve, where the Haywood kernel has been used.

J-holomorphic curves and quantum cohomology

CERN Document Server

McDuff, Dusa

1994-01-01

J-holomorphic curves revolutionized the study of symplectic geometry when Gromov first introduced them in 1985. Through quantum cohomology, these curves are now linked to many of the most exciting new ideas in mathematical physics. This book presents the first coherent and full account of the theory of J-holomorphic curves, the details of which are presently scattered in various research papers. The first half of the book is an expository account of the field, explaining the main technical aspects. McDuff and Salamon give complete proofs of Gromov's compactness theorem for spheres and of the existence of the Gromov-Witten invariants. The second half of the book focuses on the definition of quantum cohomology. The authors establish that this multiplication exists, and give a new proof of the Ruan-Tian result that is associative on appropriate manifolds. They then describe the Givental-Kim calculation of the quantum cohomology of flag manifolds, leading to quantum Chern classes and Witten's calculation for Gras...

Self-assembled structures in d8-polystyreneblock- polyisoprene/polystyrene blends in the weak segregation regime: SAXS and TEM study

Czech Academy of Sciences Publication Activity Database

Holoubek, Jaroslav; Baldrian, Josef; Hromádková, Jiřina; Steinhart, Miloš

2009-01-01

Roč. 58, č. 7 (2009), s. 762-774 ISSN 0959-8103 R&D Projects: GA ČR GA202/09/2078; GA ČR GESON/06/E005 Institutional research plan: CEZ:AV0Z40500505 Keywords : diblock copolymers * homopolymer/copolymer blends * SAXS Subject RIV: CD - Macromolecular Chemistry Impact factor: 2.137, year: 2009

Time-resolved SAXS studies of morphological changes in a blend of linear polyethylene with homogeneous ethylene-1-octene copolymer

Energy Technology Data Exchange (ETDEWEB)

Ślusarczyk, Czesław, E-mail: cslusarczyk@ath.bielsko.pl

2015-12-01

Isothermal melt crystallization in the 15/85 (m/m) blend of a high density polyethylene (HDPE) and a homogeneous ethylene copolymer with 5.5 mol% 1-octene was studied by time-resolved SAXS method with synchrotron radiation over a wide-range of crystallization temperatures. The SAXS profile was analyzed by means of the correlation function which allows to elucidate the evolution of the morphological parameters of polyethylene lamellar structure (long period (LP), thicknesses of crystalline (L{sub C}) and amorphous (L{sub A}) layers) during a crystallization process. It was found that for the samples crystallized at 100 °C, 120 °C and 122 °C L{sub C} increases with time. The lamellar thickening rate strongly depends on crystallization temperature. At 40 °C thickening of the crystalline layers does not occur. The time evolution of the lamellar structure in the blend studied confirms the role of hexyl branches of homogeneous copolymer in the crystallization process of polyethylene. The branches introduce steric constraints which hinder the crystallization of HDPE, thus decreasing the size of the HDPE lamellar crystals.

Quantification of vertical movement of low elevation topography combining a new compilation of global sea-level curves and scattered marine deposits (Armorican Massif, western France)

Science.gov (United States)

Bessin, Paul; Guillocheau, François; Robin, Cécile; Braun, Jean; Bauer, Hugues; Schroëtter, Jean-Michel

2017-07-01

A wide range of methods are available to quantify Earth's surface vertical movements but most of these methods cannot track low amplitude (5 Ma, e.g. cosmogenic isotope studies) vertical movements characteristic of plate interiors. The difference between the present-day elevation of ancient sea-level markers (deduced from well dated marine deposits corrected from their bathymetry of deposition) and a global sea-level (GSL) curve are sometimes used to estimate these intraplate vertical movements. Here, we formalized this method by re-assessing the reliability of published GSL curves to build a composite curve that combines the most reliable ones at each stage, based on the potential bias and uncertainties inherent to each curve. We suggest i) that curves which reflect ocean basin volume changes are suitable for the ca. 100 to 35 Ma ;greenhouse; period ii) whereas curves that reflects ocean water volume changes are better suited for the ca. 35 to 0 Ma ;icehouse; interval and iii) that, for these respective periods, the fit is best when using curves that accounts for both volume changes. We used this composite GSL curve to investigate the poorly constrained Paleogene to Neogene vertical motions of the Armorican Massif (western France). It is characterized by a low elevation topography, a Variscan basement with numerous well dated Cenozoic marine deposits scattered upon it. Using our method, we identify low amplitude vertical movements ranging from 66 m of subsidence to 89 m of uplift over that time period. Their spatial distribution argues for a preferred scale of deformation at medium wavelengths (i.e., order 100 km), which we relate to the deformation history of northwestern European lithosphere in three distinct episodes. i) A phase of no deformation between 38 and 34 Ma, that has been previously recognized at the scale of northwestern Europe, ii) a phase of low subsidence between 30 and 3.6 Ma, possibly related to buckling of the lithosphere and iii) a phase of

Direct monitoring of calcium-triggered phase transitions in cubosomes using small-angle X-ray scattering combined with microfluidics

DEFF Research Database (Denmark)

Ghazal, Aghiad; Gontsarik, Mark; Kutter, Jörg P.

2016-01-01

This article introduces a simple microfluidic device that can be combined with synchrotron small-angle X-ray scattering (SAXS) for monitoring dynamic structural transitions. The microfluidic device is a thiol-ene-based system equipped with 125 µm-thick polystyrene windows, which are suitable for ....... The combination of microfluidics with X-ray techniques can be used for investigating protein unfolding, for monitoring the formation of nanoparticles in real time, and for other biomedical and pharmaceutical investigations.......-ray experiments. The device was prepared by soft lithography using elastomeric molds followed by a simple UV-initiated curing step to polymerize the chip material and simultaneously seal the device with the polystyrene windows. The microfluidic device was successfully used to explore the dynamics...

Small angle X-ray scattering and cross-linking for data assisted protein structure prediction in CASP 12 with prospects for improved accuracy

KAUST Repository

Ogorzalek, Tadeusz L.

2018-01-04

Experimental data offers empowering constraints for structure prediction. These constraints can be used to filter equivalently scored models or more powerfully within optimization functions toward prediction. In CASP12, Small Angle X-ray Scattering (SAXS) and Cross-Linking Mass Spectrometry (CLMS) data, measured on an exemplary set of novel fold targets, were provided to the CASP community of protein structure predictors. As HT, solution-based techniques, SAXS and CLMS can efficiently measure states of the full-length sequence in its native solution conformation and assembly. However, this experimental data did not substantially improve prediction accuracy judged by fits to crystallographic models. One issue, beyond intrinsic limitations of the algorithms, was a disconnect between crystal structures and solution-based measurements. Our analyses show that many targets had substantial percentages of disordered regions (up to 40%) or were multimeric or both. Thus, solution measurements of flexibility and assembly support variations that may confound prediction algorithms trained on crystallographic data and expecting globular fully-folded monomeric proteins. Here, we consider the CLMS and SAXS data collected, the information in these solution measurements, and the challenges in incorporating them into computational prediction. As improvement opportunities were only partly realized in CASP12, we provide guidance on how data from the full-length biological unit and the solution state can better aid prediction of the folded monomer or subunit. We furthermore describe strategic integrations of solution measurements with computational prediction programs with the aim of substantially improving foundational knowledge and the accuracy of computational algorithms for biologically-relevant structure predictions for proteins in solution. This article is protected by copyright. All rights reserved.

Small angle X-ray scattering and cross-linking for data assisted protein structure prediction in CASP 12 with prospects for improved accuracy

KAUST Repository

Ogorzalek, Tadeusz L.; Hura, Greg L.; Belsom, Adam; Burnett, Kathryn H.; Kryshtafovych, Andriy; Tainer, John A.; Rappsilber, Juri; Tsutakawa, Susan E.; Fidelis, Krzysztof

2018-01-01

Experimental data offers empowering constraints for structure prediction. These constraints can be used to filter equivalently scored models or more powerfully within optimization functions toward prediction. In CASP12, Small Angle X-ray Scattering (SAXS) and Cross-Linking Mass Spectrometry (CLMS) data, measured on an exemplary set of novel fold targets, were provided to the CASP community of protein structure predictors. As HT, solution-based techniques, SAXS and CLMS can efficiently measure states of the full-length sequence in its native solution conformation and assembly. However, this experimental data did not substantially improve prediction accuracy judged by fits to crystallographic models. One issue, beyond intrinsic limitations of the algorithms, was a disconnect between crystal structures and solution-based measurements. Our analyses show that many targets had substantial percentages of disordered regions (up to 40%) or were multimeric or both. Thus, solution measurements of flexibility and assembly support variations that may confound prediction algorithms trained on crystallographic data and expecting globular fully-folded monomeric proteins. Here, we consider the CLMS and SAXS data collected, the information in these solution measurements, and the challenges in incorporating them into computational prediction. As improvement opportunities were only partly realized in CASP12, we provide guidance on how data from the full-length biological unit and the solution state can better aid prediction of the folded monomer or subunit. We furthermore describe strategic integrations of solution measurements with computational prediction programs with the aim of substantially improving foundational knowledge and the accuracy of computational algorithms for biologically-relevant structure predictions for proteins in solution. This article is protected by copyright. All rights reserved.

Intermediate structures in alpha scattering on 28Si nuclei

International Nuclear Information System (INIS)

Kamys, B.; Bobrovska, A.; Budzanovski, A. et al.

1975-01-01

Excitation functions and angular distributions of α-particles scattering on 28 Si nuclei, measured by various authors, are analyzed. Theoretical processing of results is divided into two stages: statistical analysis and analysis in terms of the Regge pole model (RPM). The aim of the statistical analysis is to demonstrate that the structure of excitation curves contains resonance effects. RMP with non-resonance background, described by the optical model (OM), is used to obtain data on properties of intermediate resonances. Autocorrelation functions for one elastic and two inelastic scattering channels are calculated. The mean width of compound states is about 100keV, which is in a good agreement with results of other authores. An analysis of correlation coefficients calculated for all pairs of excitation curves for elastic and two inelastic channels points to the existence of intermediate resonances in each of investigated reaction channels. In the case of large-angle scattering the contribution of potential interaction into the total cross-section is 20-30%, and that of resonance scattering is 50-60%. Energy dependence of Regge pole parameters has also been studied to obtain data on the existence and properties of intermediate resonances

Applications of Total Scattering & Pair Distribution Function Analysis in Metal-Organic Framework Materials

DEFF Research Database (Denmark)

Xu, Hui; Birgisson, Steinar; Sommer, Sanna

structure. At the same time, there is an ongoing debate on whether the SBU is present prior, or during MOF crystallization in MOF chemistry. However, little is known about MOFs formation mechanism. Currently techniques to study the in situ MOF formation process mainly focused on after......-crystallization process, for example in situ XRD and SAXS/WAXS study on MOF formation. However, the pre-crystallization process in the early stage of MOF formation is still unexplored. In this project, total scattering and PDF study will be carried out to explore the MOF formation process in early stage. This includes......Metal-Organic Frameworks (MOFs) is constructed by metal-oxide nodes and organic ligands. The formation of different structures of metal-oxide nodes (also called secondary building units, SBU) is crucial for MOF final structures, because the connectivity of SBU greatly influence the final MOF...

Structure of PEP-PEO block copolymer micelles: Exploiting the complementarity of small-angle X-ray scattering and static light scattering

DEFF Research Database (Denmark)

Jensen, Grethe Vestergaard; Shi, Qing; Hernansanz, María J.

2011-01-01

)-b-poly(ethylene oxide) (PEP-PEO) in a 70% ethanol solution are investigated. The polymers have identical PEP blocks of 5.0 kDa and varying PEO blocks of 2.8-49 kDa. The SLS contrasts of PEP and PEO are similar, providing a homogeneous contrast, making SLS ideal for determining the overall micelle morphology. The SAXS...... contrasts of the two components are very different, allowing for resolution of the internal micelle structure. A core-shell model with a PEP core and PEO corona is fitted simultaneously to the SAXS and SLS data using the different contrasts of the two blocks for each technique. With increasing PEO molecular...

SAXS study of transient pre-melting in chain-folded alkanes

International Nuclear Information System (INIS)

Ungar, G.; Wills, H.H.

1990-01-01

A pronounced pre-melting effect is observed in chain-folded crystals of pure monodisperse n-alkane C 246 H 494 . The effect is reversible on a short time scale, but at longer times the once-folded chain crystals are irreversibly lost as slow chain extension proceeds by solid diffusion well below the melting point. The melting process is thus monitored by rapid time-resolved small-angle X-ray (SAXS) measurements, using synchrotron radiation. The results show that the observed pronounced broadening of the DSC melting endotherm for chain-folded crystals is entirely due to genuine pre-melting of lamellar surfaces. Although a significant portion of material is already molten below the final melting point of chain-folded crystals T F , no recrystallization in the chain-extended form can occur until the cores of the crystalline lamellae melt at T F . Pre-melting of extended chain crystals is significantly less pronounced than that of folded chain crystals

Core–Shell Structure and Aggregation Number of Micelles Composed of Amphiphilic Block Copolymers and Amphiphilic Heterografted Polymer Brushes Determined by Small-Angle X-ray Scattering

Energy Technology Data Exchange (ETDEWEB)

Szymusiak, Magdalena; Kalkowski, Joseph; Luo, Hanying; Donovan, Alexander J.; Zhang, Pin; Liu, Chang; Shang, Weifeng; Irving, Thomas; Herrera-Alonso, Margarita; Liu, Ying (JHU); (IIT); (UIC)

2017-08-31

A large group of functional nanomaterials employed in biomedical applications, including targeted drug delivery, relies on amphiphilic polymers to encapsulate therapeutic payloads via self-assembly processes. Knowledge of the micelle structures will provide critical insights into design of polymeric drug delivery systems. Core–shell micelles composed of linear diblock copolymers poly(ethylene glycol)-b-poly(caprolactone) (PEG-b-PCL), poly(ethylene oxide)-b-poly(lactic acid) (PEG-b-PLA), as well as a heterografted brush consisting of a poly(glycidyl methacrylate) backbone with PEG and PLA branches (PGMA-g-PEG/PLA) were characterized by dynamic light scattering (DLS) and small-angle X-ray scattering (SAXS) measurements to gain structural information regarding the particle morphology, core–shell size, and aggregation number. The structural information at this quasi-equilibrium state can also be used as a reference when studying the kinetics of polymer micellization.

Core–Shell Structure and Aggregation Number of Micelles Composed of Amphiphilic Block Copolymers and Amphiphilic Heterografted Polymer Brushes Determined by Small-Angle X-ray Scattering

Energy Technology Data Exchange (ETDEWEB)

Szymusiak, Magdalena [Department; Kalkowski, Joseph [Department; Luo, Hanying [Department; Donovan, Alexander J. [Department; Zhang, Pin [Department; Liu, Chang [Department; Shang, Weifeng [Department; Irving, Thomas [Department; Herrera-Alonso, Margarita [Department; Liu, Ying [Department; Department

2017-08-16

A large group of functional nanomaterials employed in biomedical applications, including targeted drug delivery, relies on amphiphilic polymers to encapsulate therapeutic payloads via self-assembly processes. Knowledge of the micelle structures will provide critical insights into design of polymeric drug delivery systems. Core–shell micelles composed of linear diblock copolymers poly(ethylene glycol)-b-poly(caprolactone) (PEG-b-PCL), poly(ethylene oxide)-b-poly(lactic acid) (PEG-b-PLA), as well as a heterografted brush consisting of a poly(glycidyl methacrylate) backbone with PEG and PLA branches (PGMA-g-PEG/PLA) were characterized by dynamic light scattering (DLS) and small-angle X-ray scattering (SAXS) measurements to gain structural information regarding the particle morphology, core–shell size, and aggregation number. The structural information at this quasi-equilibrium state can also be used as a reference when studying the kinetics of polymer micellization.

Blown films of PA6/MMT nanocomposites: structural characterization by SAXs

International Nuclear Information System (INIS)

Marini, J.; Beatrice, C.A.G.; Lucas, A.A.; Bretas, R.E.S.

2016-01-01

In this work the influence of the processing conditions (take up and blow up ratios, TUR and BUR, respectively) in the nano-periodicity and lamellae orientation of PA6 nanocomposites blown films with natural (MMT) and organically modified montmorillonite (oMMT) was studied by SAXS. Unexpectedly, a preferred orientation of the crystalline lamellae along the normal direction (ND) was observed for all analyzed films. Such behavior can be explained by the preservation of the initial lamellae orientation of the PA6 chains imposed by the spiral flow in the die, almost null elastic recovery and fast crystallization kinetics of PA6 at the processing conditions applied. The orientation of the nanoparticles (measured by TEM) showed to be directly dependent on the TUR and BUR. The presence of the reinforcing fillers and the different processing conditions showed no significant influence on the nanoperiodicity. (author)

A Neutron Scattering Study of Collective Excitations in Superfluid Helium

DEFF Research Database (Denmark)

Graf, E. H.; Minkiewicz, V. J.; Bjerrum Møller, Hans

1974-01-01

Extensive inelastic-neutron-scattering experiments have been performed on superfluid helium over a wide range of energy and momentum transfers. A high-resolution study has been made of the pressure dependence of the single-excitation scattering at the first maximum of the dispersion curve over...... of the multiexcitation scattering was also studied. It is shown that the multiphonon spectrum of a simple Debye solid with the phonon dispersion and single-excitation cross section of superfluid helium qualitatively reproduces these data....

Structural dissection of human metapneumovirus phosphoprotein using small angle x-ray scattering.

Science.gov (United States)

Renner, Max; Paesen, Guido C; Grison, Claire M; Granier, Sébastien; Grimes, Jonathan M; Leyrat, Cédric

2017-11-01

The phosphoprotein (P) is the main and essential cofactor of the RNA polymerase (L) of non-segmented, negative-strand RNA viruses. P positions the viral polymerase onto its nucleoprotein-RNA template and acts as a chaperone of the nucleoprotein (N), thereby preventing nonspecific encapsidation of cellular RNAs. The phosphoprotein of human metapneumovirus (HMPV) forms homotetramers composed of a stable oligomerization domain (P core ) flanked by large intrinsically disordered regions (IDRs). Here we combined x-ray crystallography of P core with small angle x-ray scattering (SAXS)-based ensemble modeling of the full-length P protein and several of its fragments to provide a structural description of P that captures its dynamic character, and highlights the presence of varyingly stable structural elements within the IDRs. We discuss the implications of the structural properties of HMPV P for the assembly and functioning of the viral transcription/replication machinery.

State of mixing of deuterated and non-deuterated block polymer chains

International Nuclear Information System (INIS)

Hasegawa, Hirokazu; Hashimoto, Takeji

1984-01-01

Prior to the small-angle neutron scattering study on the conformation of block polymer chains in the domain space, the state of mixing of two block polymers, an ordinary polystyrene-polyisoprene diblock polymer and a poly(deuterated styrene)-polyisoprene diblock polymer with a different molecular weight and composition, was investigated by a small-angle X-ray scattering (SAXS) technique. Only one kind of domain structure was observed for each blend, and the domain spacings obtained by SAXS were proportional to the two-thirds power of the number-average molecular weight of the blends (reduced to non-deuterated block polymer). The volume fractions of polystyrene domain in the blends evaluated by computer simulation of SAXS profiles well agreed with the values estimated from blend composition. All these facts suggest the molecular mixing of the two block polymers in the domain space. (author)

Lattice Waves, Spin Waves, and Neutron Scattering

Science.gov (United States)

Brockhouse, Bertram N.

1962-03-01

Use of neutron inelastic scattering to study the forces between atoms in solids is treated. One-phonon processes and lattice vibrations are discussed, and experiments that verified the existence of the quantum of lattice vibrations, the phonon, are reviewed. Dispersion curves, phonon frequencies and absorption, and models for dispersion calculations are discussed. Experiments on the crystal dynamics of metals are examined. Dispersion curves are presented and analyzed; theory of lattice dynamics is considered; effects of Fermi surfaces on dispersion curves; electron-phonon interactions, electronic structure influence on lattice vibrations, and phonon lifetimes are explored. The dispersion relation of spin waves in crystals and experiments in which dispersion curves for spin waves in Co-Fe alloy and magnons in magnetite were obtained and the reality of the magnon was demonstrated are discussed. (D.C.W)

A scatter-corrected list-mode reconstruction and a practical scatter/random approximation technique for dynamic PET imaging

International Nuclear Information System (INIS)

Cheng, J-C; Rahmim, Arman; Blinder, Stephan; Camborde, Marie-Laure; Raywood, Kelvin; Sossi, Vesna

2007-01-01

We describe an ordinary Poisson list-mode expectation maximization (OP-LMEM) algorithm with a sinogram-based scatter correction method based on the single scatter simulation (SSS) technique and a random correction method based on the variance-reduced delayed-coincidence technique. We also describe a practical approximate scatter and random-estimation approach for dynamic PET studies based on a time-averaged scatter and random estimate followed by scaling according to the global numbers of true coincidences and randoms for each temporal frame. The quantitative accuracy achieved using OP-LMEM was compared to that obtained using the histogram-mode 3D ordinary Poisson ordered subset expectation maximization (3D-OP) algorithm with similar scatter and random correction methods, and they showed excellent agreement. The accuracy of the approximated scatter and random estimates was tested by comparing time activity curves (TACs) as well as the spatial scatter distribution from dynamic non-human primate studies obtained from the conventional (frame-based) approach and those obtained from the approximate approach. An excellent agreement was found, and the time required for the calculation of scatter and random estimates in the dynamic studies became much less dependent on the number of frames (we achieved a nearly four times faster performance on the scatter and random estimates by applying the proposed method). The precision of the scatter fraction was also demonstrated for the conventional and the approximate approach using phantom studies

Nonlocal Effects of Crack Curving.

Science.gov (United States)

1982-07-01

close vTcinity of the crack tip. Supported by the Office of Naval Research. 2 For brittle solids, a fracture criterion based on the maximum tensile...Reidel Pubi. Co. Dordrecht. Holland. pp. 271-318, 1978. [13] A.S. Jayatilaka, Fracture of Engineering Brittle Materials, Appl. Sci. Publishers, London...Crescent leach Road, Glen Cove * Long Island, New Tork 11542 Commanding Officer (2) U.s Amy Research Office PO, Sax 12211 Research Triangle Park. C 27709 8

Crystallization and melting behavior of poly(ethylene oxide) and its blend with styrene-based ionomer using time-resolved SAXS/WAXS experiments

Energy Technology Data Exchange (ETDEWEB)

Slusarczyk, CzesLaw, E-mail: cslusarczyk@ath.bielsko.pl [Institute of Textile Engineering and Polymer Materials, University of Bielsko-BiaLa, ul. Willowa 2, 43-309 Bielsko-BiaLa (Poland)

2011-10-15

Time-resolved synchrotron wide- and small-angle X-ray scattering experiments were used to investigate the crystallization behavior and microstructure development of neat poly(ethylene oxide) (PEO) and its 50/50 blend with ionomer containing 6.4 mol% of sodium acrylate. The apparent lateral crystal sizes D{sub (120)} and D{sub (112)/(004)} were derived from the WAXS profiles. It was found that D{sub (120)} and D{sub (112)/(004)} of PEO in the blend are almost independent of temperature and are smaller when compared to those of neat PEO sample. The evolution of morphological parameters extracted from time-resolved SAXS profiles such as the long period L, the lamellar crystal thickness l{sub C} and the amorphous layer thickness l{sub A}, shows that the crystallization process of neat PEO follows the nucleation theory. The lamellar crystal thickness l{sub C} shows a single linear dependence on inverse supercooling, over the whole temperature range investigated. In contrast, the crystallization process of PEO in the blend (i.e. in the presence of interactions with the ionomer) follows the nucleation theory only in the narrow supercooling range. It was found also that the morphology of the blend consists of a broad population of lamellar crystal thicknesses. During heating lamellae melt in the reversed sequence of their formation.

Discovery of decaHz flaring in SAX J1808.4-3658

Directory of Open Access Journals (Sweden)

Bult P.

2014-01-01

Full Text Available We report on the discovery of strong decaHz flaring in the early decay of two out of five outbursts of the accreting millisecond X-ray pulsar SAX J1808.4-3658. The decaHz flaring switches on and, after ~3 days, off again, on a time scale of 1-2 hours. When the flaring is present, the total 0.05-10 Hz variability has a fractional rms amplitude of 20 to 30 percent, well in excess of the 8 to 12 percent rms broad-band noise usually seen in power spectra of SAX J1808 in this frequency range. Coherent 401 Hz pulsations are seen throughout the observations in which the decaHz flaring is detected. We find that the absolute amplitude of the pulsations varies with the flux modulation of the decaHz flaring, indicating that the flaring is caused by an accretion rate modulation already present in the accretion flow prior to matter entering the accretion funnel. We suggest that the decaHz flaring is the result of the Spruit-Taam instability [1]. This instability arises when the inner accretion disk approaches co-rotation. The rotation of the stellar magnetosphere then acts as a propeller, suppressing accretion onto the neutron star. A matter reservoir forms in the inner accretion disk, which episodically empties onto the neutron star, causing flares at a decaHz timescale. A similar explanation was proposed earlier for 1 Hz flaring occurring late in three of five outbursts, mutually exclusive with the decaHz flaring. The 1 Hz flaring was observed at luminosities a factor 5 to 10 below where we see the decaHz flaring. That a different branch of the Spruit-Taam instability could also act at the much higher luminosity levels of the decaHz flaring had recently been predicted by D’Angelo & Spruit [2, 3]. We discuss these findings in the context of the parameters of the Spruit-Taam-d’Angelo model of the instability. If confirmed, after millisecond pulsations, 1 Hz and decaHz flaring would be another diagnostic of the presence of a magnetosphere in accreting low

Considerations for Sample Preparation Using Size-Exclusion Chromatography for Home and Synchrotron Sources.

Science.gov (United States)

Rambo, Robert P

2017-01-01

The success of a SAXS experiment for structural investigations depends on two precise measurements, the sample and the buffer background. Buffer matching between the sample and background can be achieved using dialysis methods but in biological SAXS of monodisperse systems, sample preparation is routinely being performed with size exclusion chromatography (SEC). SEC is the most reliable method for SAXS sample preparation as the method not only purifies the sample for SAXS but also almost guarantees ideal buffer matching. Here, I will highlight the use of SEC for SAXS sample preparation and demonstrate using example proteins that SEC purification does not always provide for ideal samples. Scrutiny of the SEC elution peak using quasi-elastic and multi-angle light scattering techniques can reveal hidden features (heterogeneity) of the sample that should be considered during SAXS data analysis. In some cases, sample heterogeneity can be controlled using a small molecule additive and I outline a simple additive screening method for sample preparation.

Constrained Maximum Likelihood Estimation of Relative Abundances of Protein Conformation in a Heterogeneous Mixture from Small Angle X-Ray Scattering Intensity Measurements

Science.gov (United States)

Onuk, A. Emre; Akcakaya, Murat; Bardhan, Jaydeep P.; Erdogmus, Deniz; Brooks, Dana H.; Makowski, Lee

2015-01-01

In this paper, we describe a model for maximum likelihood estimation (MLE) of the relative abundances of different conformations of a protein in a heterogeneous mixture from small angle X-ray scattering (SAXS) intensities. To consider cases where the solution includes intermediate or unknown conformations, we develop a subset selection method based on k-means clustering and the Cramér-Rao bound on the mixture coefficient estimation error to find a sparse basis set that represents the space spanned by the measured SAXS intensities of the known conformations of a protein. Then, using the selected basis set and the assumptions on the model for the intensity measurements, we show that the MLE model can be expressed as a constrained convex optimization problem. Employing the adenylate kinase (ADK) protein and its known conformations as an example, and using Monte Carlo simulations, we demonstrate the performance of the proposed estimation scheme. Here, although we use 45 crystallographically determined experimental structures and we could generate many more using, for instance, molecular dynamics calculations, the clustering technique indicates that the data cannot support the determination of relative abundances for more than 5 conformations. The estimation of this maximum number of conformations is intrinsic to the methodology we have used here. PMID:26924916

Probabilistic evaluation of design S-N curve and reliability assessment of ASME code-based evaluation

International Nuclear Information System (INIS)

Zhao Yongxiang

1999-01-01

A probabilistic evaluating approach of design S-N curve and a reliability assessment approach of the ASME code-based evaluation are presented on the basis of Langer S-N model-based P-S-N curves. The P-S-N curves are estimated by a so-called general maximum likelihood method. This method can be applied to deal with the virtual stress amplitude-crack initial life data which have a characteristics of double random variables. Investigation of a set of the virtual stress amplitude-crack initial life (S-N) data of 1Cr18Ni9Ti austenitic stainless steel-welded joint reveals that the P-S-N curves can give a good prediction of scatter regularity of the S-N data. Probabilistic evaluation of the design S-N curve with 0.9999 survival probability has considered various uncertainties, besides of the scatter of the S-N data, to an appropriate extent. The ASME code-based evaluation with 20 reduction factor on the mean life is much more conservative than that with 2 reduction factor on the stress amplitude. Evaluation of the latter in 666.61 MPa virtual stress amplitude is equivalent to 0.999522 survival probability and in 2092.18 MPa virtual stress amplitude equivalent to 0.9999999995 survival probability. This means that the evaluation in the low loading level may be non-conservative and in contrast, too conservative in the high loading level. Cause is that the reduction factors are constants and the factors can not take into account the general observation that scatter of the N data increases with the loading level decreasing. This has indicated that it is necessary to apply the probabilistic approach to the evaluation of design S-N curve

WaveSAX device: design optimization through scale modelling and a PTO strategical control system

Science.gov (United States)

Peviani, Maximo; Danelli, Andrea; Dadone, Gianluca; Dalmasso, Alberto

2017-04-01

WaveSAX is an innovative OWC (Oscillating Water Column) device for the generation of electricity from wave power, conceived to be installed in coastal marine structures, such as ports and harbours. The device - especially designed for the typical wave climate of Mediterranean Sea - is characterized by two important aspects: flexibility to fit in different structural configurations and replication in a large number of units. A model of the WaveSAX device on a scale 1:5 has been built and tested in the ocean tank at Ecole Centrale de Nantes (France). The study aimed to analyse the behaviour of the device, including two Wells turbine configurations (with three and four blades), with regular and irregular wave conditions in the ocean wave tank. The model and the wave basin were equipped with a series of sensors which allowed to measure the following parameters during the tests: pressure in different points inside the device, the free water surface displacement inside and outside the device, the rotational velocity and the torque at the top of the axis. The tests had the objective to optimize the device design, especially as far as the characteristics of the rotor of the turbine is concern. Although the performance of the WaveSAX has been satisfactory for regular wave conditions, the behaviour of the Wells turbines for irregular wave climate has shown limitations in terms of maintaining the capacity to transform hydraulics energy into mechanical power. To optimize the efficiency of the turbine, an electronical system has been built on the basis of the ocean tank tests. It allows to continuously monitor and command the rotational speed and the torque of the rotor connected with the turbine, and to control in real time the electrical flow of a motor-generator, either absorbing energy as a generator, or providing power to the turbine working as an engine. Two strategies - based on the velocity and the torque control - have been investigate in the electronic test bench

Versatile application of indirect Fourier transformation to structure factor analysis: from X-ray diffraction of molecular liquids to small angle scattering of protein solutions.

Science.gov (United States)

Fukasawa, Toshiko; Sato, Takaaki

2011-02-28

We highlight versatile applicability of a structure-factor indirect Fourier transformation (IFT) technique, hereafter called SQ-IFT. The original IFT aims at the pair distance distribution function, p(r), of colloidal particles from small angle scattering of X-rays (SAXS) and neutrons (SANS), allowing the conversion of the experimental form factor, P(q), into a more intuitive real-space spatial autocorrelation function. Instead, SQ-IFT is an interaction potential model-free approach to the 'effective' or 'experimental' structure factor to yield the pair correlation functions (PCFs), g(r), of colloidal dispersions like globular protein solutions for small-angle scattering data as well as the radial distribution functions (RDFs) of molecular liquids in liquid diffraction (LD) experiments. We show that SQ-IFT yields accurate RDFs of liquid H(2)O and monohydric alcohol reflecting their local intermolecular structures, in which q-weighted structure function, qH(q), conventionally utilized in many LD studies out of necessity of performing direct Fourier transformation, is no longer required. We also show that SQ-IFT applied to theoretically calculated structure factors for uncharged and charged colloidal dispersions almost perfectly reproduces g(r) obtained as a solution of the Ornstein-Zernike (OZ) equation. We further demonstrate the relevance of SQ-IFT in its practical applications, using SANS effective structure factors of lysozyme solutions reported in recent literatures which revealed the equilibrium cluster formation due to coexisting long range electrostatic repulsion and short range attraction between the proteins. Finally, we present SAXS experiments on human serum albumin (HSA) at different ionic strength and protein concentration, in which we discuss the real space picture of spatial distributions of the proteins via the interaction potential model-free route.

Simulating Microwave Scattering for Wetland Vegetation in Poyang Lake, Southeast China, Using a Coherent Scattering Model

Directory of Open Access Journals (Sweden)

Jingjuan Liao

2015-07-01

Full Text Available We developed a polarimetric coherent electromagnetic scattering model for Poyang Lake wetland vegetation. Realistic canopy structures including curved leaves and the lodging situation of the vegetation were taken into account, and the situation at the ground surface was established using an Advanced Integral Equation Model combined with Oh’s 2002 model. This new model can reasonably describe the coherence effect caused by the phase differences of the electromagnetic fields scattered from different particles by different scattering mechanisms. We obtained good agreement between the modeling results and C-band data from the Radarsat-2 satellite. A simulation of scattering from the vegetation in Poyang Lake showed that direct vegetation scattering and the single-ground-bounce mechanism are the dominant scattering mechanisms in the C-band and L-band, while the effects of the double-ground-bounce mechanism are very small. We note that the curvature of the leaves and the lodging characteristics of the vegetation cannot be ignored in the modeling process. Monitoring soil moisture in the Poyang Lake wetland with the C-band data was not feasible because of the density and depth of Poyang Lake vegetation. When the density of Poyang Lake Carex increases, the backscattering coefficient either decreases or remains stable.

Multi-MW wind turbine power curve measurements using remote sensing instruments - the first Hoevsoere campaign

Energy Technology Data Exchange (ETDEWEB)

Wagner, R.; Courtney, M.

2009-02-15

Power curve measurement for large wind turbines requires taking into account more parameters than only the wind speed at hub height. Based on results from aerodynamic simulations, an equivalent wind speed taking the wind shear into account was defined and found to reduce the scatter in the power curve significantly. Two LiDARs and a SoDAR are used to measure the wind profile in front of a wind turbine. These profiles are used to calculate the equivalent wind speed. LiDAR are found to be more accurate than SoDAR and therefore more suitable for power performance measurement. The equivalent wind speed calculated from LiDAR profile measurements gave a small reduction of the power curve uncertainty. Several factors can explain why this difference is smaller than expected, including the experimental design and errors pertaining to the LiDAR at that time. This first measurement campaign shows that used of the equivalent wind speed at least results in a power curve with no more scatter than using the conventional method. (au)

Fulltext PDF

Indian Academy of Sciences (India)

Abstract. We report a combined use of small-angle neutron scattering (SANS) and small-angle X-ray scattering (SAXS) to the study of counterion condensation in ionic micelles. Small-angle neutron and X-ray scattering measurements have been carried out on two surfactants cetyltrimethylammonium bromide (CTABr) and ...

In Situ Lipolysis and Synchrotron Small-Angle X-ray Scattering for the Direct Determination of the Precipitation and Solid-State Form of a Poorly Water-Soluble Drug During Digestion of a Lipid-Based Formulation

DEFF Research Database (Denmark)

Khan, Jamal; Hawley, Adrian; Rades, Thomas

2016-01-01

In situ lipolysis and synchrotron small-angle X-ray scattering (SAXS) were used to directly detect and elucidate the solid-state form of precipitated fenofibrate from the digestion of a model lipid-based formulation (LBF). This method was developed in light of recent findings that indicate variab...... on drugs, and experimental conditions, which are anticipated to produce altered solid-state forms upon the precipitation of drug (i.e., polymorphs, amorphous forms, and salts). © 2015 Wiley Periodicals, Inc. and the American Pharmacists Association J Pharm Sci....

Solution structure of a short dna fragment studied by neutron scattering

DEFF Research Database (Denmark)

Lederer, H.; May, R. P.; Kjems, Jørgen

1986-01-01

-DNA. The neutron scattering curve is well fitted by that of a rigid rod with a length of 44 nm and a diameter of 2 nm. The result were confirmed by quasi-elastic light scattering and analytical centrifugation. The neutron measurements in H2O and D2O buffer reveal a cross-sectional in homogeneity not detected by X...

Light scattering in ecology and bio medicine; Rasejanje svetlosti u ekologiji i biomedicini

Energy Technology Data Exchange (ETDEWEB)

Sreckovic, M [Belgrade Univ. (Yugoslavia). Elektrotehnicki Fakultet; Ostojic, S [Belgrade Univ. (Yugoslavia). Tehnolosko-Metalurski Fakultet; Mamula-Tartalja, D [Visa Tehnicka PPT skola, Belgrade(Yugoslavia); Arandjelovic, S [Zavod za DDD, Belgrade (Yugoslavia); Stekovic, M [Belgrade Univ. (Yugoslavia). Elektrotehnicki Fakultet

1996-07-01

In the paper chosen experiments of application of light scattering in ecology and medicine are considered. Based on experimental curves, distribution of micro scatterers in micrometer and manometer particle size area is estimated and the question of corresponding mathematics devices for representing the given distribution is considered. For obtained distributions some definition parameters and needed number of parameters in order to distinguish certain categories of scatterers have been discussed. (author)

REFLECTED LIGHT CURVES, SPHERICAL AND BOND ALBEDOS OF JUPITER- AND SATURN-LIKE EXOPLANETS

Energy Technology Data Exchange (ETDEWEB)

Dyudina, Ulyana; Kopparla, Pushkar; Ingersoll, Andrew P.; Yung, Yuk L. [Division of Geological and Planetary Sciences, 150-21 California Institute of Technology, Pasadena, CA 91125 (United States); Zhang, Xi [University of California Santa Cruz 1156 High Street, Santa Cruz, CA 95064 (United States); Li, Liming [Department of Physics, University of Houston, Houston, TX 77204 (United States); Dones, Luke [Southwest Research Institute, 1050 Walnut Street, Suite 300, Boulder CO 80302 (United States); Verbiscer, Anne, E-mail: ulyana@gps.caltech.edu [Department of Astronomy, University of Virginia, Charlottesville, VA 22904-4325 (United States)

2016-05-10

Reflected light curves observed for exoplanets indicate that a few of them host bright clouds. We estimate how the light curve and total stellar heating of a planet depends on forward and backward scattering in the clouds based on Pioneer and Cassini spacecraft images of Jupiter and Saturn. We fit analytical functions to the local reflected brightnesses of Jupiter and Saturn depending on the planet’s phase. These observations cover broadbands at 0.59–0.72 and 0.39–0.5 μ m, and narrowbands at 0.938 (atmospheric window), 0.889 (CH4 absorption band), and 0.24–0.28 μ m. We simulate the images of the planets with a ray-tracing model, and disk-integrate them to produce the full-orbit light curves. For Jupiter, we also fit the modeled light curves to the observed full-disk brightness. We derive spherical albedos for Jupiter and Saturn, and for planets with Lambertian and Rayleigh-scattering atmospheres. Jupiter-like atmospheres can produce light curves that are a factor of two fainter at half-phase than the Lambertian planet, given the same geometric albedo at transit. The spherical albedo is typically lower than for a Lambertian planet by up to a factor of ∼1.5. The Lambertian assumption will underestimate the absorption of the stellar light and the equilibrium temperature of the planetary atmosphere. We also compare our light curves with the light curves of solid bodies: the moons Enceladus and Callisto. Their strong backscattering peak within a few degrees of opposition (secondary eclipse) can lead to an even stronger underestimate of the stellar heating.

Evolution of magnetism on a curved nano-surface.

Science.gov (United States)

Merkel, D G; Bessas, D; Zolnai, Z; Rüffer, R; Chumakov, A I; Paddubrouskaya, H; Van Haesendonck, C; Nagy, N; Tóth, A L; Deák, A

2015-08-14

To design custom magnetic nanostructures, it is indispensable to acquire precise knowledge about the systems in the nanoscale range where the magnetism forms. In this paper we present the effect of a curved surface on the evolution of magnetism in ultrathin iron films. Nominally 70 Å thick iron films were deposited in 9 steps on 3 different types of templates: (a) a monolayer of silica spheres with 25 nm diameter, (b) a monolayer of silica spheres with 400 nm diameter and (c) for comparison a flat silicon substrate. In situ iron evaporation took place in an ultrahigh vacuum chamber using the molecular beam epitaxy technique. After the evaporation steps, time differential nuclear forward scattering spectra, grazing incidence small angle X-ray scattering images and X-ray reflectivity curves were recorded. In order to reconstruct and visualize the magnetic moment configuration in the iron cap formed on top of the silica spheres, micromagnetic simulations were performed for all iron thicknesses. We found a great influence of the template topography on the onset of magnetism and on the developed magnetic nanostructure. We observed an individual magnetic behaviour for the 400 nm spheres which was modelled by vortex formation and a collective magnetic structure for the 25 nm spheres where magnetic domains spread over several particles. Depth selective nuclear forward scattering measurements showed that the formation of magnetism begins at the top region of the 400 nm spheres in contrast to the 25 nm particles where the magnetism first appears in the region where the spheres are in contact with each other.

Additional information about the chemistry of precipitates by variation of the scattering contrast in SANS and SAXS experiments

International Nuclear Information System (INIS)

Grosse, M.

1999-01-01

Contrast variation experiments provide the possibility to get information about the chemical composition of heterogeneities seen in the small angle scattering experiment. Phases in complex materials can become visible or invisible by changing the contrast. A very important question in this field is the determination of the type of precipitates which are formed during neutron irradiation. These irradiation-induced precipitates are the cause for the neutron embrittlement, which is the life time limiting process for a nuclear power plant. An example is presented, which shows that with contrast variation experiments information about chemical composition of precipitates can be obtained. Several phases in complex materials can be separated. (K.A.)

Refined tropical curve counts and canonical bases for quantum cluster algebras

DEFF Research Database (Denmark)

Mandel, Travis

We express the (quantizations of the) Gross-Hacking-Keel-Kontsevich canonical bases for cluster algebras in terms of certain (Block-Göttsche) weighted counts of tropical curves. In the process, we obtain via scattering diagram techniques a new invariance result for these Block-Göttsche counts....

Matter-wave scattering and guiding by atomic arrays

International Nuclear Information System (INIS)

Vaishnav, J. Y.; Walls, J. D.; Apratim, M.; Heller, E. J.

2007-01-01

We investigate the possibility that linear arrays of atoms can guide matter waves, much as fiber optics guide light. We model the atomic line as a quasi-one-dimensional array of s-wave point scatterers embedded in two-dimensions. Our theoretical study reveals how matter-wave guiding arises from the interplay of scattering phenomena with bands and conduction along the array. We discuss the conditions under which a straight or curved array of atoms can guide a beam focused at one end of the array

Scattering on plane waves and the double copy

Science.gov (United States)

Adamo, Tim; Casali, Eduardo; Mason, Lionel; Nekovar, Stefan

2018-01-01

Perturbatively around flat space, the scattering amplitudes of gravity are related to those of Yang–Mills by colour-kinematic duality, under which gravitational amplitudes are obtained as the ‘double copy’ of the corresponding gauge theory amplitudes. We consider the question of how to extend this relationship to curved scattering backgrounds, focusing on certain ‘sandwich’ plane waves. We calculate the 3-point amplitudes on these backgrounds and find that a notion of double copy remains in the presence of background curvature: graviton amplitudes on a gravitational plane wave are the double copy of gluon amplitudes on a gauge field plane wave. This is non-trivial in that it requires a non-local replacement rule for the background fields and the momenta and polarization vectors of the fields scattering on the backgrounds. It must also account for new ‘tail’ terms arising from scattering off the background. These encode a memory effect in the scattering amplitudes, which naturally double copies as well.

Nanospheres with a smectic hydrophobic core and an amorphous PEG hydrophilic shell: structural changes and implications for drug delivery

Energy Technology Data Exchange (ETDEWEB)

Murthy, N. Sanjeeva [New Jersey Center for Biomaterials; Rutgers; The State University of New Jersey; Piscataway; USA; Zhang, Zheng [New Jersey Center for Biomaterials; Rutgers; The State University of New Jersey; Piscataway; USA; Borsadia, Siddharth [New Jersey Center for Biomaterials; Rutgers; The State University of New Jersey; Piscataway; USA; Kohn, Joachim [New Jersey Center for Biomaterials; Rutgers; The State University of New Jersey; Piscataway; USA

2018-01-01

The structural changes in nanospheres with a crystalline core and an amorphous diffuse shell were investigated by small-angle neutron scattering (SANS), small-, medium-, and wide-angle X-ray scattering (SAXS, MAXS and WAXS), and differential scanning calorimetry (DSC).

Guided wave propagation and scattering in pipeworks comprising elbows: Theoretical and experimental results

International Nuclear Information System (INIS)

Bakkali, M El; Lhémery, A; Baronian, V; Chapuis, B

2015-01-01

Elastic guided waves (GW) are used to inspect pipeworks in various industries. Modelling tools for simulating GW inspection are necessary to understand complex scattering phenomena occurring at specific features (welds, elbows, junctions...). In pipeworks, straight pipes coexist with elbows. GW propagation in the former cases is well-known, but is less documented in the latter. Their scattering at junction of straight and curved pipes constitutes a complex phenomenon. When a curved part is joined to two straight parts, these phenomena couple and give rise to even more complex wave structures. In a previous work, the SemiAnalytic Finite Element method extended to curvilinear coordinates was used to handle GW propagation in elbows, combined with a mode matching method to predict their scattering at the junction with a straight pipe. Here, a pipework comprising an arbitrary number of elbows of finite length and of different curvature linking straight pipes is considered. A modal scattering matrix is built by cascading local scattering and propagation matrices. The overall formulation only requires meshing the pipe section to compute both the modal solutions and the integrals resulting from the mode-matching method for computing local scattering matrices. Numerical predictions using this approach are studied and compared to experiments

Inelastic electron scattering influence on the strong coupling oxide superconductors

International Nuclear Information System (INIS)

Gabovich, A.M.; Voitenko, A.I.

1995-01-01

The superconducting order parameters Δ and energy gap Δ g are calculated taking into account the pair-breaking inelastic quasiparticle scattering by thermal Bose-excitations, e.g., phonons. The treatment is self-consistent because the scattering amplitude depends on Δ. The superconducting transition for any strength of the inelastic scattering is the phase transition of the first kind and the dependences Δ (T) and Δ g (T) tend to rectangular curve that agrees well with the experiment for high-Tc oxides. On the basis of the developed theory the nuclear spin-lattice relaxation rate R s in the superconducting state is calculated. The Hebel-Slichter peak in R s (T) is shown to disappear for strong enough inelastic scattering

The interpretation of polycrystalline coherent inelastic neutron scattering from aluminium

Science.gov (United States)

Roach, Daniel L.; Ross, D. Keith; Gale, Julian D.; Taylor, Jon W.

2013-01-01

A new approach to the interpretation and analysis of coherent inelastic neutron scattering from polycrystals (poly-CINS) is presented. This article describes a simulation of the one-phonon coherent inelastic scattering from a lattice model of an arbitrary crystal system. The one-phonon component is characterized by sharp features, determined, for example, by boundaries of the (Q, ω) regions where one-phonon scattering is allowed. These features may be identified with the same features apparent in the measured total coherent inelastic cross section, the other components of which (multiphonon or multiple scattering) show no sharp features. The parameters of the model can then be relaxed to improve the fit between model and experiment. This method is of particular interest where no single crystals are available. To test the approach, the poly-CINS has been measured for polycrystalline aluminium using the MARI spectrometer (ISIS), because both lattice dynamical models and measured dispersion curves are available for this material. The models used include a simple Lennard-Jones model fitted to the elastic constants of this material plus a number of embedded atom method force fields. The agreement obtained suggests that the method demonstrated should be effective in developing models for other materials where single-crystal dispersion curves are not available. PMID:24282332

Hybrid aerogels and bioactive aerogels under uniaxial compression: an in situ SAXS study

Directory of Open Access Journals (Sweden)

Esquivias, L.

2010-12-01

Full Text Available The complex structure of hybrid organic/inorganic aerogels is composed by an inorganic phase covalently bonded to an organic chain forming a copolymer. Conventional hybrid aerogels were studied as well as bioactive hybrid aerogels, that is, aerogels with a calcium active phase added. In this work, the relationship between mechanical response and nanostructure was studied, using a specifically designed sample-holder for in situ uniaxial compression obtaining at the same time the small-angle X-ray pattern from synchrotron radiation (SAXS. Structural elements can be described as a particulated silica core surrounded by the organic chains. These chains are compressed on the direction parallel to the load, and a relationship between macroscopic uniaxial compression and particle and pore deformations can be established.

La compleja estructura de los aerogeles híbridos orgánico/inorgánicos está compuesta por una fase inorgánica de sílice, unida mediante enlaces covalentes a una red de cadenas orgánicas. Se han estudiado composites híbridos convencionales y bioactivos, esto es, con una fase activa de calcio añadida. En este trabajo se ha investigado la relación entre la respuesta mecánica y la nanoestructura, con ayuda de un portamuestras específicamente diseñado para el estudio in situ de muestras bajo compresión uniaxial, a la vez que se obtiene el espectro de rayos-X a bajo-ángulo de radiación sincrotrón (SAXS. Los elementos estructurales se pueden describir como núcleos particulados de sílice rodeados de las cadenas orgánicas. Estas, se comprimen en la dirección paralela a la carga pudiéndose establecer una relación entre la compresión uniaxial macroscópica y la deformación de las partículas y poros que forman la estructura.

Inelastic X-ray scattering activities in Europe

International Nuclear Information System (INIS)

Dorner, B.

1984-01-01

Inelastic X-ray scattering requires an energy determination before and after the scattering process together with a technique to vary at least one energy continuously in a controlled way. Sufficiently monochromatic beams can only be produced by Bragg reflection from single crystals. Stationary X-ray monochromators are standard equipment of conventional X-ray generators to select a particular characteristic line. Quite often they are curved to focus on the sample or the detector. Devices with variable Bragg angle have been and are used as analyzers in Compton scattering which is inelastic X-ray scattering with moderate resolution. With the rapidly increasing availability of synchrotron radiation (SR) monochromators and analyzers became more and more sophisticated improving momentum (Q) resolution and only somewhat the energy resolution ΔE which stays in the order of eV. Very high energy resolution can only be obtained with Bragg angles Theta near to 90 0 . This field is the topic of the present paper

X-ray scatter data for diagnostic radiology

International Nuclear Information System (INIS)

Dick, C.E.; Soares, C.G.; Motz, J.W.

1978-01-01

The ratio of the scattered to the total X-ray fluence (scatter fraction) at the centre of the image plane for X-rays transmitted through polystyrene phantoms has been measured for X-ray energies of 32 and 69 keV, X-ray beam diameters from 4 to 40 cm, phantom thicknesses from 5 to 30 cm and phantom-to-image-plane separations from 0.3 to 40 cm. The experimental values for this ratio have less than a 10% variation for these two X-ray energies and the experimental data show good agreement with Monte Carlo calculations and available experimental results for low atomic number materials. Based on these results, simple curves are generated which give estimates (+ - 10%) of the scatter fraction for all combinations of the geometric parameters encountered in diagnostic radiology. (author)

Silica-filled elastomers polymer chain and filler characterization by a SANS-SAXS approach

CERN Document Server

Botti, A; Richter, D; Urban, V; Ipns, A 6 4; Kohlbrecher, J; Straube, E

2002-01-01

A study of composites based upon commercially available silica fillers and networks of blends of protonated and deuterated anionically prepared polyisoprene is presented. The extraction of the single chain structure factor for SANS in the polymeric soft phase in isotropic and deformed state has been performed for the first time. The quasi three-component system could not be compositionally matched due to the internal structures of the activated fillers. For this, a parallel SAXS investigation provided the neccessary information on the filler structure which was lacking in the SANS analysis. Whereas mechanically clear reinforcement at low strains and filler-networking can be observed, the microscopic characterization of the chain deformation in the framework of the network tube model agrees with the estimates for hydrodynamic reinforcement of fractal fillers. (orig.)

Silica-filled elastomers: polymer chain and filler characterization by a SANS-SAXS approach

International Nuclear Information System (INIS)

Botti, A.; Pyckhout-Hintzen, W.; Richter, D.; Urban, V.; Kohlbrecher, J.; Straube, E.

2002-01-01

A study of composites based upon commercially available silica fillers and networks of blends of protonated and deuterated anionically prepared polyisoprene is presented. The extraction of the single chain structure factor for SANS in the polymeric soft phase in isotropic and deformed state has been performed for the first time. The quasi three-component system could not be compositionally matched due to the internal structures of the activated fillers. For this, a parallel SAXS investigation provided the neccessary information on the filler structure which was lacking in the SANS analysis. Whereas mechanically clear reinforcement at low strains and filler-networking can be observed, the microscopic characterization of the chain deformation in the framework of the network tube model agrees with the estimates for hydrodynamic reinforcement of fractal fillers. (orig.)

The Adhesion Molecule KAL-1/anosmin-1 Regulates Neurite Branching through a SAX-7/L1CAM–EGL-15/FGFR Receptor Complex

Directory of Open Access Journals (Sweden)

Carlos A. Díaz-Balzac

2015-06-01

Full Text Available Neurite branching is essential for correct assembly of neural circuits, yet it remains a poorly understood process. For example, the neural cell adhesion molecule KAL-1/anosmin-1, which is mutated in Kallmann syndrome, regulates neurite branching through mechanisms largely unknown. Here, we show that KAL-1/anosmin-1 mediates neurite branching as an autocrine co-factor with EGL-17/FGF through a receptor complex consisting of the conserved cell adhesion molecule SAX-7/L1CAM and the fibroblast growth factor receptor EGL-15/FGFR. This protein complex, which appears conserved in humans, requires the immunoglobulin (Ig domains of SAX-7/L1CAM and the FN(III domains of KAL-1/anosmin-1 for formation in vitro as well as function in vivo. The kinase domain of the EGL-15/FGFR is required for branching, and genetic evidence suggests that ras-mediated signaling downstream of EGL-15/FGFR is necessary to effect branching. Our studies establish a molecular pathway that regulates neurite branching during development of the nervous system.

Study on the structure of Fe sub 2 O sub 3 xerogels by small angle X-ray scattering

CERN Document Server

Liu Yi; Zhao Xin; Yang Tong Hua; Zhao Hui; Rong Li Xia; Zhang Jing; Wang Jun; Dong Bao Zhong

2002-01-01

Small angle X-ray scattering (SAXS) with synchrotron radiation as X-ray source is used to study the pore structure of Fe sub 2 O sub 3 xerogels prepared by sol-gel procedure and then heat-treated at different temperatures. By analysing the distribution of diameters of the pores, specific surfaces and fractal behaviors in samples, the characters and mechanisms of pores growing are discussed. The results show that the pores in Fe sub 2 O sub 3 xerogels are polydisperse and the structure of the pores is mass fractal. With increase in heat-treatment temperature, the average size of diameters of the pores and the dimension of fractal of Fe sub 2 O sub 3 xerogels are increased, whereas the scale range possessing fractal behavior become narrow

Time- and position-resolved synchrotron x-ray scattering for structure research on biological connective tissue

International Nuclear Information System (INIS)

Zizak, I.

2000-03-01

Different experiments on connective tissue using synchrotron radiation were performed during the course of this thesis. The accent was on collagen containing connective tissue, such as tendon, bone and cartilage. The high brilliance of synchrotron radiation was used to perform the experiments with high temporal or spatial resolution. In particular, a device for scanning small-angle scattering was developed for the use at synchrotron radiation sources, and used to study the interface between bone and cartilage. Tensile experiments on tendons: Tendons are highly hierarchically structured tissue consisting mostly of collagen. Complex organization on all levels results in a complicated visco-elastic mechanical behavior. Stretched to small amounts, tendon is easily deformed. However, if the stress grows, the stress strain curve bends upwards and finally the fibers show linear stress-strain dependence. Due to the complex structure of the tissue, the processes that control these bio-mechanical properties are not known in detail yet. Thus, it is very important to determine the hierarchical levels at which the viscous and elastic processes occur. We concentrated our studies to rat tail tendons, which consist mostly of collagen fibers. By investigating this system, we could gain some fundamental information about the way of assembling the collagen molecules in the fibers, as well as the interfibrillar connections. Tensile measurements on tendons give insight into the stress-strain characteristic of the tendon. Simultaneous acquisition of the structure function in a scattering experiment provides information on the processes at the molecular level, particularly the stretching of the collagen fibrils. To perform these two kinds of measurements simultaneously, a special device was used. Due to the speed of the processes, relative fast x-ray detectors and high intensity of the x-ray beam were required. Thus, the experiments were performed at the synchrotron radiation source

Structure investigation of metal ions clustering in dehydrated gel using x-ray anomalous dispersion effect

CERN Document Server

Soejima, Y; Sugiyama, M; Annaka, M; Nakamura, A; Hiramatsu, N; Hara, K

2003-01-01

The structure of copper ion clusters in dehydrated N-isopropylacrylamide/sodium acrylate (NIPA/SA) gel has been studied by means of small angle X-ray scattering (SAXS) method. In order to distinguish the intensity scattered by Cu ions, the X-ray anomalous dispersion effect around the Cu K absorption edge has been coupled with SAXS. It is found that the dispersion effect dependent on the incident X-ray energy is remarkable only at the momentum transfer q = 0.031 A sup - sup 1 , where a SAXS peak is observed. The results indicate that copper ions form clusters in the dehydrated gel, and that the mean size of clusters is the same as that of SA clusters produced by microphase separation. It is therefore naturally presumed that copper ions are adsorbed into the SA molecules. On the basis of the presumption, a mechanism is proposed for microphase-separation and clustering of Cu ions.

Conformational Ensemble of the Poliovirus 3CD Precursor Observed by MD Simulations and Confirmed by SAXS: A Strategy to Expand the Viral Proteome?

Science.gov (United States)

Moustafa, Ibrahim M; Gohara, David W; Uchida, Akira; Yennawar, Neela; Cameron, Craig E

2015-11-23

The genomes of RNA viruses are relatively small. To overcome the small-size limitation, RNA viruses assign distinct functions to the processed viral proteins and their precursors. This is exemplified by poliovirus 3CD protein. 3C protein is a protease and RNA-binding protein. 3D protein is an RNA-dependent RNA polymerase (RdRp). 3CD exhibits unique protease and RNA-binding activities relative to 3C and is devoid of RdRp activity. The origin of these differences is unclear, since crystal structure of 3CD revealed "beads-on-a-string" structure with no significant structural differences compared to the fully processed proteins. We performed molecular dynamics (MD) simulations on 3CD to investigate its conformational dynamics. A compact conformation of 3CD was observed that was substantially different from that shown crystallographically. This new conformation explained the unique properties of 3CD relative to the individual proteins. Interestingly, simulations of mutant 3CD showed altered interface. Additionally, accelerated MD simulations uncovered a conformational ensemble of 3CD. When we elucidated the 3CD conformations in solution using small-angle X-ray scattering (SAXS) experiments a range of conformations from extended to compact was revealed, validating the MD simulations. The existence of conformational ensemble of 3CD could be viewed as a way to expand the poliovirus proteome, an observation that may extend to other viruses.

How Noniridescent Colors Are Generated by Quasi-ordered Structures of Bird Feathers

Energy Technology Data Exchange (ETDEWEB)

Noh, Heeso; Liew, Seng Fatt; Saranathan, Vinodkumar; Mochrie, Simon G.J.; Prum, Richard O.; Dufresne, Eric R.; Cao, Hui (Yale)

2012-03-26

We investigate the mechanism of structural coloration by quasi-ordered nanostructures in bird feather barbs. Small-angle X-ray scattering (SAXS) data reveal the structures are isotropic and have short-range order on length scales comparable to optical wavelengths. We perform angle-resolved reflection and scattering spectrometry to fully characterize the colors under directional and omni-directional illumination of white light. Under directional lighting, the colors change with the angle between the directions of illumination and observation. The angular dispersion of the primary peaks in the scattering/reflection spectra can be well explained by constructive interference of light that is scattered only once in the quasi-ordered structures. Using the Fourier power spectra of structure from the SAXS data we calculate optical scattering spectra and explain why the light scattering peak is the highest in the backscattering direction. Under omni-directional lighting, colors from the quasi-ordered structures are invariant with the viewing angle. The non-iridescent coloration results from the isotropic nature of structures instead of strong backscattering.

Use of precracked Charpy and smaller specimens to establish the master curve

International Nuclear Information System (INIS)

Sokolov, M.A.; McCabe, D.E.; Nanstad, R.K.; Davidov, Y.A.

1997-01-01

The current provisions used in the U.S. Code of Federal Regulations for the determination of the fracture toughness of reactor pressure vessel steels employs an assumption that there is a direct correlation between K Ic lower-bound toughness and the Charpy V-notch transition curve. Such correlations are subject to scatter from both approaches which weakens the reliability of fracture mechanics-based analyses. In this study, precracked Charpy and smaller size specimens are used in three-point static bend testing to develop fracture mechanics based K k values. The testing is performed under carefully controlled conditions such that the values can be used to predict the fracture toughness performance of large specimens. The concept of a universal transition curve (master curve) is applied. Data scatter that is characteristic of commercial grade steels and their weldments is handled by Weibull statistical modeling. The master curve is developed to describe the median K Jc fracture toughness for 1T size compact specimens. Size effects are modeled using weakest-link theory and are studied for different specimen geometries. It is shown that precracked Charpy specimens when tested within their confined validity limits follow the weakest-link size-adjustment trend and predict the fracture toughness of larger specimens. Specimens of smaller than Charpy sizes (5 mm thick) exhibit some disparities in results relative to weakest-link size adjustment prediction suggesting that application of such adjustment to very small specimens may have some limitations

Investigation of the collagen-mineral-relation in bone with special respect to bone diseases with collagen defects by small-angle X-ray scattering

International Nuclear Information System (INIS)

Schreiber, S. A.

1996-06-01

Small-angle X-ray scattering (SAXS) was used to study the structure of the collagen/mineral composite of bone in the nanometer range. The most important results were: - In horse radius, the angular distribution of mineral crystals as measured by SAXS agreed well with previous measurements of collagen orientation using circularly polarized light microscopy. This shows that the crystals are parallel to the collagen fibrils. - The effect of sodium fluoride, which stimulates bone formation, and bisphosphonates, which reduce bone resorption, were analyzed. A slight increase in the average thickness of the mineral crystals as well as changes in the structure of the mineral/collagen composite were found in the case of fluoride treated animals. No differences were found between alendronate treated animals and controls. The changes with NaF correlate with bone weakening found in an earlier study with the same animals. - In cortical bone from 9 patients with Osteogenesis Imperfecta (brittle bone disease) the mean thickness of the mineral crystals was found approximately constant around 2.4 nm, while in control bones it constantly increased with age up to about 3.5 nm. In addition, the parallel alignment of the mineral crystals was less in OI-bone than in normal controls. Hence, despite the great variability of this genetic collagen defect, smaller and less well aligned mineral crystals seem to characterize the collagen/mineral composite in OI-bone. (author)

First results of saturation curve measurements of heat-resistant steel using GEANT4 and MCNP5 codes

International Nuclear Information System (INIS)

Hoang, Duc-Tam; Tran, Thien-Thanh; Le, Bao-Tran; Vo, Hoang-Nguyen; Chau, Van-Tao; Tran, Kim-Tuyet; Huynh, Dinh-Chuong

2015-01-01

A gamma backscattering technique is applied to calculate the saturation curve and the effective mass attenuation coefficient of material. A NaI(Tl) detector collimated by collimator of large diameter is modeled by Monte Carlo technique using both MCNP5 and GEANT4 codes. The result shows a good agreement in response function of the scattering spectra for the two codes. Based on such spectra, the saturation curve of heat-resistant steel is determined. The results represent a strong confirmation that it is appropriate to use the detector collimator of large diameter to obtain the scattering spectra and this work is also the basis of experimental set-up for determining the thickness of material. (author)

Ultra-small-angle X-ray scattering characterization of diesel/gasoline soot: sizes and particle-packing conditions

Science.gov (United States)

Kameya, Yuki; Lee, Kyeong O.

2013-10-01

Regulations on particulate emissions from internal combustion engines tend to become more stringent, accordingly the importance of particulate filters in the after-treatment system has been increasing. In this work, the applicability of ultra-small-angle X-ray scattering (USAXS) to diesel soot cake and gasoline soot was investigated. Gasoline-direct-injection engine soot was collected at different fuel injection timings. The unified fits method was applied to analyze the resultant scattering curves. The validity of analysis was supported by comparing with carbon black and taking the sample images using a transmission electron microscope, which revealed that the primary particle size ranged from 20 to 55 nm. In addition, the effects of particle-packing conditions on the USAXS measurement were demonstrated by using samples suspended in acetone. Then, the investigation was extended to characterization of diesel soot cake deposited on a diesel particulate filter (DPF). Diesel soot was trapped on a small piece of DPF at different deposition conditions which were specified using the Peclet number. The dependence of scattering curve on soot-deposition conditions was demonstrated. To support the interpretation of the USAXS results, soot cake samples were observed using a scanning electron microscope and the influence of particle-packing conditions on scattering curve was discussed.

Ultra-small-angle X-ray scattering characterization of diesel/gasoline soot: sizes and particle-packing conditions

International Nuclear Information System (INIS)

Kameya, Yuki; Lee, Kyeong O.

2013-01-01

Regulations on particulate emissions from internal combustion engines tend to become more stringent, accordingly the importance of particulate filters in the after-treatment system has been increasing. In this work, the applicability of ultra-small-angle X-ray scattering (USAXS) to diesel soot cake and gasoline soot was investigated. Gasoline-direct-injection engine soot was collected at different fuel injection timings. The unified fits method was applied to analyze the resultant scattering curves. The validity of analysis was supported by comparing with carbon black and taking the sample images using a transmission electron microscope, which revealed that the primary particle size ranged from 20 to 55 nm. In addition, the effects of particle-packing conditions on the USAXS measurement were demonstrated by using samples suspended in acetone. Then, the investigation was extended to characterization of diesel soot cake deposited on a diesel particulate filter (DPF). Diesel soot was trapped on a small piece of DPF at different deposition conditions which were specified using the Peclet number. The dependence of scattering curve on soot-deposition conditions was demonstrated. To support the interpretation of the USAXS results, soot cake samples were observed using a scanning electron microscope and the influence of particle-packing conditions on scattering curve was discussed

Ultra-small-angle X-ray scattering characterization of diesel/gasoline soot: sizes and particle-packing conditions

Energy Technology Data Exchange (ETDEWEB)

Kameya, Yuki, E-mail: ykameya@anl.gov; Lee, Kyeong O. [Argonne National Laboratory, Center for Transportation Research (United States)

2013-10-15

Regulations on particulate emissions from internal combustion engines tend to become more stringent, accordingly the importance of particulate filters in the after-treatment system has been increasing. In this work, the applicability of ultra-small-angle X-ray scattering (USAXS) to diesel soot cake and gasoline soot was investigated. Gasoline-direct-injection engine soot was collected at different fuel injection timings. The unified fits method was applied to analyze the resultant scattering curves. The validity of analysis was supported by comparing with carbon black and taking the sample images using a transmission electron microscope, which revealed that the primary particle size ranged from 20 to 55 nm. In addition, the effects of particle-packing conditions on the USAXS measurement were demonstrated by using samples suspended in acetone. Then, the investigation was extended to characterization of diesel soot cake deposited on a diesel particulate filter (DPF). Diesel soot was trapped on a small piece of DPF at different deposition conditions which were specified using the Peclet number. The dependence of scattering curve on soot-deposition conditions was demonstrated. To support the interpretation of the USAXS results, soot cake samples were observed using a scanning electron microscope and the influence of particle-packing conditions on scattering curve was discussed.

Surface Fitting for Quasi Scattered Data from Coordinate Measuring Systems.

Science.gov (United States)

Mao, Qing; Liu, Shugui; Wang, Sen; Ma, Xinhui

2018-01-13

Non-uniform rational B-spline (NURBS) surface fitting from data points is wildly used in the fields of computer aided design (CAD), medical imaging, cultural relic representation and object-shape detection. Usually, the measured data acquired from coordinate measuring systems is neither gridded nor completely scattered. The distribution of this kind of data is scattered in physical space, but the data points are stored in a way consistent with the order of measurement, so it is named quasi scattered data in this paper. Therefore they can be organized into rows easily but the number of points in each row is random. In order to overcome the difficulty of surface fitting from this kind of data, a new method based on resampling is proposed. It consists of three major steps: (1) NURBS curve fitting for each row, (2) resampling on the fitted curve and (3) surface fitting from the resampled data. Iterative projection optimization scheme is applied in the first and third step to yield advisable parameterization and reduce the time cost of projection. A resampling approach based on parameters, local peaks and contour curvature is proposed to overcome the problems of nodes redundancy and high time consumption in the fitting of this kind of scattered data. Numerical experiments are conducted with both simulation and practical data, and the results show that the proposed method is fast, effective and robust. What's more, by analyzing the fitting results acquired form data with different degrees of scatterness it can be demonstrated that the error introduced by resampling is negligible and therefore it is feasible.

Structural characterization of silver nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Garcia, Paulo Ricardo; Sousa, Edi Carlos Pereira de; Pontuschka, Walter Maigon; Oliveira, Cristiano Luis Pinto de, E-mail: pauloricardoafg@yahoo.com.br [Universidade de Sao Paulo (USP), Sao Paulo, SP (Brazil). Instituto de Fisica

2016-07-01

Full text: Due to magnetic, optical and electrical properties metallic nanoparticles have been extensively studied to potential applications in biosensor production, separation of biological molecules, image techniques, drug delivery among several others. For such applications, it is crucial to have crystals with morphology and well defined structure. In this work we presented a detailed structured characterization of silver nanoparticles using small angle x-rays and light scattering methods. The comparison and correlation of these results with electron microscopy images permitted the determination of interesting structural parameters for the studied systems. The oscillations of the intensity curve of SAXS data reveal that this sample has particles with reasonable stability and well defined sizes. The mean radius obtained from the size distribution curve is in good agreement with the ones obtained by TEM images. As will be shown, the combination of several techniques and the correct analysis for the obtained experimental data provides unique information on the structure of the studied systems. (author)

Modelling SANS and SAXS data

International Nuclear Information System (INIS)

Reynolds, P.

1999-01-01

Full text: Small angle scattering data while on an absolute scale and relatively accurate over large ranges of observables (0.003 -1 ; 0.1 -1 ) is often relatively featureless. I will address some of the problems this causes, and some of the ways of minimising these, by reference to our recent SANS results. For the benefit of newer chums this will involve discussion of the strengths and weaknesses of data from ISIS (LOQ), Argonne (SAND) and the I.L.L. (D22), and the consequences these have for modelling. The use of simple portable or remote access systems for modelling will be discussed - in particular the IGOR based NIST system of Dr. S. Kline and the VAX based FISH system of Dr. R. Heenan, ISIS. I will illustrate that a wide variety of physically appealing and complete models are now available. If you have reason to believe in a particular microstructure, this belief can now be either falsified, or the microstructure quantified, by fitting to the entire set of scattering patterns over the entire Q-range. For example, only in cases of drastic ignorance need we use only Guinier and Porod analyses, although these may provide useful initial guidance in the modelling. We now rarely need to use oversimplified logically incomplete models - such as spherical micelles with neglect of intermicellar correlation- now that we possess fast desktop/experimental computers

Distribution functions of magnetic nanoparticles determined by a numerical inversion method

International Nuclear Information System (INIS)

Bender, P; Balceris, C; Ludwig, F; Posth, O; Bogart, L K; Szczerba, W; Castro, A; Nilsson, L; Costo, R; Gavilán, H; González-Alonso, D; Pedro, I de; Barquín, L Fernández; Johansson, C

2017-01-01

In the present study, we applied a regularized inversion method to extract the particle size, magnetic moment and relaxation-time distribution of magnetic nanoparticles from small-angle x-ray scattering (SAXS), DC magnetization (DCM) and AC susceptibility (ACS) measurements. For the measurements the particles were colloidally dispersed in water. At first approximation the particles could be assumed to be spherically shaped and homogeneously magnetized single-domain particles. As model functions for the inversion, we used the particle form factor of a sphere (SAXS), the Langevin function (DCM) and the Debye model (ACS). The extracted distributions exhibited features/peaks that could be distinctly attributed to the individually dispersed and non-interacting nanoparticles. Further analysis of these peaks enabled, in combination with a prior characterization of the particle ensemble by electron microscopy and dynamic light scattering, a detailed structural and magnetic characterization of the particles. Additionally, all three extracted distributions featured peaks, which indicated deviations of the scattering (SAXS), magnetization (DCM) or relaxation (ACS) behavior from the one expected for individually dispersed, homogeneously magnetized nanoparticles. These deviations could be mainly attributed to partial agglomeration (SAXS, DCM, ACS), uncorrelated surface spins (DCM) and/or intra-well relaxation processes (ACS). The main advantage of the numerical inversion method is that no ad hoc assumptions regarding the line shape of the extracted distribution functions are required, which enabled the detection of these contributions. We highlighted this by comparing the results with the results obtained by standard model fits, where the functional form of the distributions was a priori assumed to be log-normal shaped. (paper)

The accuracy of liquid-liquid phase transition temperatures determined from semiautomated light scattering measurements

Science.gov (United States)

Dean, Kevin M.; Babayco, Christopher B.; Sluss, Daniel R. B.; Williamson, J. Charles

2010-08-01

The synthetic-method determination of liquid-liquid coexistence curves using semiautomated light scattering instrumentation and stirred samples is based on identifying the coexistence curve transition temperatures (Tcx) from sudden changes in turbidity associated with droplet formation. Here we use a thorough set of such measurements to evaluate the accuracy of several different analysis methods reported in the literature for assigning Tcx. More than 20 samples each of weakly opalescent isobutyric acid+water and strongly opalescent aniline+hexane were tested with our instrumentation. Transmitted light and scattering intensities at 2°, 24°, and 90° were collected simultaneously as a function of temperature for each stirred sample, and the data were compared with visual observations and light scattering theory. We find that assigning Tcx to the onset of decreased transmitted light or increased 2° scattering has a potential accuracy of 0.01 K or better for many samples. However, the turbidity due to critical opalescence obscures the identification of Tcx from the light scattering data of near-critical stirred samples, and no simple rule of interpretation can be applied regardless of collection geometry. At best, when 90° scattering is collected along with transmitted or 2° data, the accuracy of Tcx is limited to 0.05 K for near-critical samples. Visual determination of Tcx remains the more accurate approach in this case.

Self-Interacting Dark Matter Can Explain Diverse Galactic Rotation Curves.

Science.gov (United States)

Kamada, Ayuki; Kaplinghat, Manoj; Pace, Andrew B; Yu, Hai-Bo

2017-09-15

The rotation curves of spiral galaxies exhibit a diversity that has been difficult to understand in the cold dark matter (CDM) paradigm. We show that the self-interacting dark matter (SIDM) model provides excellent fits to the rotation curves of a sample of galaxies with asymptotic velocities in the 25-300  km/s range that exemplify the full range of diversity. We assume only the halo concentration-mass relation predicted by the CDM model and a fixed value of the self-interaction cross section. In dark-matter-dominated galaxies, thermalization due to self-interactions creates large cores and reduces dark matter densities. In contrast, thermalization leads to denser and smaller cores in more luminous galaxies and naturally explains the flatness of rotation curves of the highly luminous galaxies at small radii. Our results demonstrate that the impact of the baryons on the SIDM halo profile and the scatter from the assembly history of halos as encoded in the concentration-mass relation can explain the diverse rotation curves of spiral galaxies.

Morphological analysis of ionomers

International Nuclear Information System (INIS)

1991-01-01

Anomalous small-angle x-ray scattering (SAXS) investigations were carried out on amorphous and semi-crystalline ionomers (Ni- neutralized sulfonated polystyrene ionomers, polyurethane ionomer). Ionomers with semicrystalline matrices (three-phase materials) were also studied with SAXS (poly(ethylene-co-methacrylic acid) ionomer). Ethylene oxide units were incorporated into the backbone of sulfonated polyurethane ionomers in an attempt to induce aggregate dissociation. Small-angle neutron scattering was used to study the effect of ionic aggregation on ionomer chain dimensions in telechelic and model polyurethane ionomers. Studies have been completed on carboxylated and sulfonated model polyurethane ionomers in order to determine the effect of the pendant ionic group on ionomer structure- property relationships (mechanical properties)

Aqueous Processing of Low-Band-Gap Polymer Solar Cells Using Roll-to-Roll Methods

DEFF Research Database (Denmark)

Andersen, Thomas Rieks; Larsen-Olsen, Thue Trofod; Andreasen, Birgitta

2011-01-01

Aqueous nanoparticle dispersions of a series of three low-band-gap polymers poly[4,8-bis(2-ethylhexyloxy)benzo(1,2-b:4,5-b′)dithiophene-alt-5,6-bis(octyloxy)-4,7-di(thiophen-2-yl)(2,1,3-benzothiadiazole)-5,5′-diyl] (P1), poly[(4,4′-bis(2-ethylhexyl)dithieno[3,2-b:2′,3′-d]silole)-2,6-diyl-alt-(2...... (SDS). The size of the nanoparticles was established using small-angle X-ray scattering (SAXS) of the aqueous dispersions and by both atomic force microscopy (AFM) and using both grazing incidence SAXS (GISAXS) and grazing incidence wide-angle X-ray scattering (GIWAXS) in the solid state as coated...

Modulated structure formation in demixing paraffin blends

International Nuclear Information System (INIS)

Gilbert, E.P.

2002-01-01

Small angle scattering (SANS and SAXS) and differential scanning calorimetry have been measured from C 28 :C 36 normal paraffin mixtures of varying composition quenched from the melt. Satellite peaks are observed in the SAXS whose offset in Q, relative to Bragg diffraction peaks associated with the average structure, are composition dependent. The offset is close to the position of the most intense peak observed in SANS. Scattering from the quenched structures is consistent with a correlated displacement and substitutional disorder model yielding modulations that are incommensurate with the average lattice. DSC shows an additional endotherm in the mixtures that is not present in the pure components and is associated with this superstructure formation. (orig.)

Molecular dynamic analysis of the structure of dendrimers

Energy Technology Data Exchange (ETDEWEB)

Canetta, E.; Maino, G. E-mail: maino@bologna.enea.it

2004-01-01

We present main results of molecular dynamics simulations that we have carried out in order to investigate structural properties of polyamidoamine (PAMAM) dendrimers. Obtained data confirm the PAMAM dendrimer structure proposed by experiments, performed by means of X-ray scattering (SAXS) and quasi-elastic light scattering (QELS) techniques.

Molecular dynamic analysis of the structure of dendrimers

International Nuclear Information System (INIS)

Canetta, E.; Maino, G.

2004-01-01

We present main results of molecular dynamics simulations that we have carried out in order to investigate structural properties of polyamidoamine (PAMAM) dendrimers. Obtained data confirm the PAMAM dendrimer structure proposed by experiments, performed by means of X-ray scattering (SAXS) and quasi-elastic light scattering (QELS) techniques

Particle shape inhomogeneity and plasmon-band broadening of solar-control LaB{sub 6} nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Machida, Keisuke; Adachi, Kenji, E-mail: kenji-adachi@ni.smm.co.jp [Ichikawa Research Laboratories, Sumitomo Metal Mining Co., Ltd., Ichikawa 272-8588 (Japan)

2015-07-07

An ensemble inhomogeneity of non-spherical LaB{sub 6} nanoparticles dispersion has been analyzed with Mie theory to account for the observed broad plasmon band. LaB{sub 6} particle shape has been characterized using small-angle X-ray scattering (SAXS) and electron tomography (ET). SAXS scattering intensity is found to vary exponentially with exponent −3.10, indicating the particle shape of disk toward sphere. ET analysis disclosed dually grouped distribution of nanoparticle dispersion; one is large-sized at small aspect ratio and the other is small-sized with scattered high aspect ratio, reflecting the dual fragmentation modes during the milling process. Mie extinction calculations have been integrated for 100 000 particles of varying aspect ratio, which were produced randomly by using the Box-Muller method. The Mie integration method has produced a broad and smooth absorption band expanded towards low energy, in remarkable agreement with experimental profiles by assuming a SAXS- and ET-derived shape distribution, i.e., a majority of disks with a little incorporation of rods and spheres for the ensemble. The analysis envisages a high potential of LaB{sub 6} with further-increased visible transparency and plasmon peak upon controlled particle-shape and its distribution.

Extraction of the missing low-Q data from small-angle scattering data

International Nuclear Information System (INIS)

Doherty, G.K.; Poland, G.A.

1996-01-01

A new method is presented that recovers the scatter intensity curve at low Q values from small-angle neutron scattering data. The method uses only the measured data, requiring no extrapolation of the scatter curve nor any a priori knowledge of the maximum chord length, radius of gyration or molecular weight of the particle under investigation. It is assumed that the incoherent level would have been extracted from the data in the normal course of events but any errors do not affect the method presented. The distance distribution function of any particle has a restricted extension in real space and any nonzero value beyond the maximum size of the particle is due to the effects of missing data segments and noise on the measured data. The effects due to the missing and noisy data are isolated from the distance distribution of the particle and a suitably scaled template particle is used to fill in the missing distribution data segment. The inverse transform of the new distribution function returns the missing low-Q scatter data and to some extent cancels out the noise. While the method is generally explored using noise-free analytically derived particles, its application to real experimental data is demonstrated. (orig.)

Neutron scattering on molten transition metals and on Fe-C melts

International Nuclear Information System (INIS)

Weber, M.

1978-01-01

In order to find out whether short-range order phenomena can be detected in iron-carbon melts, neutron scattering experiments were carried out in molten iron-carbon alloys. The method of isotope substitution, where the natural alloying iron was substituted by a 57 Fe-enriched isotope mixture, helped to increase the ratio between the scattering length of the carbon atoms and that of the iron atoms. The mean coherent scattering length for the isotope mixture which is required for further evaluation of the measurements, was determined in an experiment by measuring the limiting angle for total reflection of neutrons on evaporated films. From this determination of the scattering length, a value for the so far unknown scattering length of the 58 Fe isotope was obtained. The small angle scattering in corrected intensity curves of molten Fe-C alloys was investigated in detail. Scattering experiments in unalloyed Fe, Co, and Ni in the range of small scattering vectors proved that this small-angle scattering effect, which was observed here for the first time, is of magnetic origin. It is caused by short-range spin correlations fluctuating with space and time. [de

Experimental Method for Plotting S-N Curve with a Small Number of Specimens

Directory of Open Access Journals (Sweden)

Strzelecki Przemysław

2016-12-01

Full Text Available The study presents two approaches to plotting an S-N curve based on the experimental results. The first approach is commonly used by researchers and presented in detail in many studies and standard documents. The model uses a linear regression whose parameters are estimated by using the least squares method. A staircase method is used for an unlimited fatigue life criterion. The second model combines the S-N curve defined as a straight line and the record of random occurrence of the fatigue limit. A maximum likelihood method is used to estimate the S-N curve parameters. Fatigue data for C45+C steel obtained in the torsional bending test were used to compare the estimated S-N curves. For pseudo-random numbers generated by using the Mersenne Twister algorithm, the estimated S-N curve for 10 experimental results plotted by using the second model, estimates the fatigue life in the scatter band of the factor 3. The result gives good approximation, especially regarding the time required to plot the S-N curve.

ORNL 10-m small-angle X-ray scattering camera

International Nuclear Information System (INIS)

Hendricks, R.W.

1979-12-01

A new small-angle x-ray scattering camera utilizing a rotating anode x-ray source, crystal monochromatization of the incident beam, pinhole collimation, and a two-dimensional position-sensitive proportional counter was developed. The sample, and the resolution element of the detector are each approximately 1 x 1 mm 2 , the camera was designed so that the focal spot-to-sample and sample-to-detector distances may each be varied in 0.5-m increments up to 5 m to provide a system resolution in the range 0.5 to 4.0 mrad. A large, general-purpose specimen chamber has been provided into which a wide variety of special-purpose specimen holders can be mounted. The detector has an active area of 200 x 200 mm and has up to 200 x 200 resolution elements. The data are recorded in the memory of a minicomputer by a high-speed interface which uses a microprocessor to map the position of an incident photon into an absolute minicomputer memory address. The data recorded in the computer memory can be processed on-line by a variety of programs designed to enhance the user's interaction with the experiment. At the highest angular resolution (0.4 mrad), the flux incident on the specimen is 1.0 x 10 6 photons/s with the x-ray source operating at 45 kV and 100 mA. SAX and its associated programs OVF and MOT are high-priority, pre-queued, nonresident foreground tasks which run under the ModComp II MAX III operating system to provide complete user control of the ORNL 10-m small-angle x-ray scattering camera

Time-resolved small-angle x-ray scattering study of the early stage of amyloid formation of an apomyoglobin mutant

Science.gov (United States)

Ortore, Maria Grazia; Spinozzi, Francesco; Vilasi, Silvia; Sirangelo, Ivana; Irace, Gaetano; Shukla, Anuj; Narayanan, Theyencheri; Sinibaldi, Raffaele; Mariani, Paolo

2011-12-01

The description of the fibrillogenesis pathway and the identification of “on-pathway” or “off-pathway” intermediates are key issues in amyloid research as they are concerned with the mechanism for onset of certain diseases and with therapeutic treatments. Recent results on the fibril formation process revealed an unexpected complexity both in the number and in the types of species involved, but the early aggregation events are still largely unknown, mainly because of their experimental inaccessibility. To provide information on the early stage events of self-assembly of an amyloidogenic protein, during the so-called lag phase, stopped-flow time-resolved small angle x-ray scattering (SAXS) experiments were performed. Using a global fitting analysis, the structural and aggregation properties of the apomyoglobin W7FW14F mutant, which is monomeric and partly folded at acidic pH but forms amyloid fibrils after neutralization, were derived from the first few milliseconds onward. SAXS data indicated that the first aggregates appear in less than 20 ms after the pH jump to neutrality and further revealed the simultaneous presence of diverse species. In particular, worm-like unstructured monomers, very large assemblies, and elongated particles were detected, and their structural features and relative concentrations were derived as a function of time on the basis of our model. The final results show that, during the lag phase, early assembling occurs due to the presence of transient monomeric species very prone to association and through successive competing aggregation and rearrangement processes leading to coexisting on-pathway and off-pathway transient species.

Monte Carlo calculation of scattered radiation from applicators in low energy clinical electron beams

International Nuclear Information System (INIS)

Jabbari, N.; Hashemi-Malayeri, B.; Farajollahi, A. R.; Kazemnejad, A.

2007-01-01

In radiotherapy with electron beams, scattered radiation from an electron applicator influences the dose distribution in the patient. The contribution of this radiation to the patient dose is significant, even in modern accelerators. In most of radiotherapy treatment planning systems, this component is not explicitly included. In addition, the scattered radiation produced by applicators varies based on the applicator design as well as the field size and distance from the applicators. The aim of this study was to calculate the amount of scattered dose contribution from applicators. We also tried to provide an extensive set of calculated data that could be used as input or benchmark data for advanced treatment planning systems that use Monte Carlo algorithms for dose distribution calculations. Electron beams produced by a NEPTUN 10PC medical linac were modeled using the BEAMnrc system. Central axis depth dose curves of the electron beams were measured and calculated, with and without the applicators in place, for different field sizes and energies. The scattered radiation from the applicators was determined by subtracting the central axis depth dose curves obtained without the applicators from that with the applicator. The results of this study indicated that the scattered radiation from the electron applicators of the NEPTUN 10PC is significant and cannot be neglected in advanced treatment planning systems. Furthermore, our results showed that the scattered radiation depends on the field size and decreases almost linearly with depth. (author)

Light scattering from a binary-liquid entanglement gel

Science.gov (United States)

Xia, K.-Q.; Maher, J. V.

1987-09-01

Light-scattering experiments have been carried out on an entanglement gel with a binary-liquid mixture as solvent. The onset temperature for critical opalescence has a composition dependence which is similar to the coexistence curve of the free-liquid mixture. This system resembles previously reported work on the cross-linked gel polyacrylamide in two ways: (1) As temperature is lowered toward the critical temperature of the free-liquid mixture, the binary-fluid gel exhibits a strong and increasing light scattering over a broad temperature region of several kelvins, and (2) no appreciable temporal fluctuations are observed throughout this temperature region. Two added features are observed in the present, entanglement-gel measurements: (a) Gel samples with solvent composition both near and off the critical composition of the free-liquid mixture exhibit similar light-scattering behavior, and (b) a Lorentzian-squared fit to the light-scattering angular distributions yields a characteristic wave number which does not change with temperature and an amplitude which shows a very strong dependence on the temperature.

Interaction between β-lactoglobulin and structurally different heteroexopolysaccharides investigated by solution scattering and analytical ultracentrifugation study

DEFF Research Database (Denmark)

Khan, Sanaullah; Birch, Johnny; Harris, Pernille

strongly with these HePSs. β-lactoglobulin exists as a dimer at pH 4 in the absence of HePSs. When mixed with HePSs, SAXS analysis showed that β-lactoglobulin formed large aggregates. DLS also showed formation of large aggregates of β-lactoglobulin with HePSs, thus validating SAXS data. Turbidity and AUC...... heteroexopolysaccharides (HePS-1–HePS-4) from lactic acid bacteria (LAB) and their interactions with β-lactoglobulin. We have previously shown that these HePSs exhibited a compact conformation in solution. Here, SAXS data for HePSs (HePS-1–HePS-4) complexes with β-lactoglobulin showed that β-lactoglobulin aggregated...... data indicated that both soluble and insoluble BLG–HePSs complexes were formed. This study provides new insights into the role of molecular structures in associative interactions between HePSs and BLG which has relevance for various industrial applications....

Batch-wise adsorption, saxs and microscopic studies of zeolite pelletized with biopolymeric alginate

Directory of Open Access Journals (Sweden)

E. Chmielewská

2011-03-01

Full Text Available Removal of nitrates, sulfate and Zn(II ions from aqueous solutions through adsorption onto biopolymeric alginate/clinoptilolite-rich tuff pellets was studied by using an equilibrium batch technique. The idea of this approach of biosorbent fabrication is to promote the native zeolite adsorption performance and thus to prepare more efficient amphoteric tailor-made products for specific environmental targets. A flexible component, i.e., alginate biopolymer, and a rigid component (pulverized zeolite were crosslinked using Fe(III and Ca(II chlorides, additively. The extent of adsorption was found to be considerably higher than with the other mostly natural adsorbents examined towards similar pollutants. The equilibrium adsorption data for the above pollutants were satisfactorily fitted to Freundlich and Langmuir isotherms, respectively. According to the linscale SAXS pattern, there was a strong background visible, which may indicate the presence of a considerable amount of biopolymeric phase in the composite samples analysed. Scanning Tunneling, Electron and Atomic Force Microscopies helped visualize their surface texture and morphology.

Development of probabilistic fatigue curve for asphalt concrete based on viscoelastic continuum damage mechanics

Directory of Open Access Journals (Sweden)

Himanshu Sharma

2016-07-01

Full Text Available Due to its roots in fundamental thermodynamic framework, continuum damage approach is popular for modeling asphalt concrete behavior. Currently used continuum damage models use mixture averaged values for model parameters and assume deterministic damage process. On the other hand, significant scatter is found in fatigue data generated even under extremely controlled laboratory testing conditions. Thus, currently used continuum damage models fail to account the scatter observed in fatigue data. This paper illustrates a novel approach for probabilistic fatigue life prediction based on viscoelastic continuum damage approach. Several specimens were tested for their viscoelastic properties and damage properties under uniaxial mode of loading. The data thus generated were analyzed using viscoelastic continuum damage mechanics principles to predict fatigue life. Weibull (2 parameter, 3 parameter and lognormal distributions were fit to fatigue life predicted using viscoelastic continuum damage approach. It was observed that fatigue damage could be best-described using Weibull distribution when compared to lognormal distribution. Due to its flexibility, 3-parameter Weibull distribution was found to fit better than 2-parameter Weibull distribution. Further, significant differences were found between probabilistic fatigue curves developed in this research and traditional deterministic fatigue curve. The proposed methodology combines advantages of continuum damage mechanics as well as probabilistic approaches. These probabilistic fatigue curves can be conveniently used for reliability based pavement design. Keywords: Probabilistic fatigue curve, Continuum damage mechanics, Weibull distribution, Lognormal distribution

Application of multiple scattering theory in electron dosimetry

International Nuclear Information System (INIS)

Oliveira, M.J.G.S. de.

1984-01-01

A theoretical model, based on the Fermi-Eyges scattering theory, which takes into account the different heterogeneous media, is proposed. Heterogeneous phantoms were built in order to obtain curves of distribution of the absorbed dose. The agreement between the theoretical and experimental data prove that presented theory model is useful to describe the absorbed dose in homogeneous media. (M.A.C.) [pt

Curves and tables of neutron cross sections

International Nuclear Information System (INIS)

Nakagawa, Tsuneo; Asami, Tetsuo; Yoshida, Tadashi

1990-07-01

Neutron cross-section curves from the Japanese Evaluated Nuclear Data Library version 3, JENDL-3, are presented in both graphical and tabular form for users in a wide range of application areas in the nuclear energy field. The contents cover cross sections for all the main reactions induced by neutrons with an energy below 20 MeV including; total, elastic scattering, capture, and fission, (n,n'), (n,2n), (n,3n), (n,α), (n,p) reactions. The 2200 m/s cross-section values, resonance integrals, and Maxwellian- and fission-spectrum averaged cross sections are also tabulated. (author)

Structural model of the 50S subunit of E.Coli ribosomes from solution scattering

Energy Technology Data Exchange (ETDEWEB)

Svergun, D.I.; Koch, M.H.J. [Hamburg Outstation (Germany); Pedersen, J.S. [Riso National Laboratory, Roskilde (Denmark); Serdyuk, I.N. [Inst. of Protein Research, Moscow (Russian Federation)

1994-12-31

The application of new methods of small-angle scattering data interpretation to a contrast variation study of the 50S ribosomal subunit of Escherichia coli in solution is described. The X-ray data from contrast variation with sucrose are analyzed in terms of the basic scattering curves from the volume inaccessible to sucrose and from the regions inside this volume occupied mainly by RNA and by proteins. From these curves models of the shape of the 50S and its RNA-rich core are evaluated and positioned so that their difference produces a scattering curve which is in good agreement with the scattering from the protein moiety. Basing on this preliminary model, the X-ray and neutron contrast variation data of the 50S subunit in aqueous solutions are interpreted in the frame of the advanced two-phase model described by the shapes of the 50S subunit and its RNA-rich core taking into account density fluctuations inside the RNA and the protein moiety. The shape of the envelope of the 50S subunit and of the RNA-rich core are evaluated with a resolution of about 40A. The shape of the envelope is in good agreement with the models of the 50S subunit obtained from electron microscopy on isolated particles. The shape of the RNA-rich core correlates well with the model of the entire particle determined by the image reconstruction from ordered sheets indicating that the latter model which is based on the subjective contouring of density maps is heavily biased towards the RNA.

Structural model of the 50S subunit of E.Coli ribosomes from solution scattering

International Nuclear Information System (INIS)

Svergun, D.I.; Koch, M.H.J.; Pedersen, J.S.; Serdyuk, I.N.

1994-01-01

The application of new methods of small-angle scattering data interpretation to a contrast variation study of the 50S ribosomal subunit of Escherichia coli in solution is described. The X-ray data from contrast variation with sucrose are analyzed in terms of the basic scattering curves from the volume inaccessible to sucrose and from the regions inside this volume occupied mainly by RNA and by proteins. From these curves models of the shape of the 50S and its RNA-rich core are evaluated and positioned so that their difference produces a scattering curve which is in good agreement with the scattering from the protein moiety. Basing on this preliminary model, the X-ray and neutron contrast variation data of the 50S subunit in aqueous solutions are interpreted in the frame of the advanced two-phase model described by the shapes of the 50S subunit and its RNA-rich core taking into account density fluctuations inside the RNA and the protein moiety. The shape of the envelope of the 50S subunit and of the RNA-rich core are evaluated with a resolution of about 40A. The shape of the envelope is in good agreement with the models of the 50S subunit obtained from electron microscopy on isolated particles. The shape of the RNA-rich core correlates well with the model of the entire particle determined by the image reconstruction from ordered sheets indicating that the latter model which is based on the subjective contouring of density maps is heavily biased towards the RNA

Deriving the ultrastructure of α-crustacyanin using lower-resolution structural and biophysical methods

International Nuclear Information System (INIS)

Rhys, Natasha H.; Wang, Ming-Chuan; Jowitt, Thomas A.; Helliwell, John R.; Grossmann, J. Günter; Baldock, Clair

2011-01-01

The structure of α-crustacyanin has been determined to 30 Å resolution using negative-stain electron microscopy (EM) single-particle averaging and modelling with the β-crustacyanin dimer from the crystal structure (Protein Data Bank code), guided by PISA protein subunit interface calculations, and compared with the protein arrangements observed in the crystal lattice. This α-crustacyanin EM model has been checked against SAXS experimental data, including comparison with rigid-body models calculated from the SAXS data, and finally with analytical ultracentrifugation measurements. The low-resolution structure of α-crustacyanin has been determined to 30 Å resolution using negative-stain electron microscopy (EM) with single-particle averaging. The protein, which is an assembly of eight β-crustacyanin dimers, appears asymmetrical and rather open in layout. A model was built to the EM map using the X-ray crystallographic structure of β-crustacyanin guided by PISA interface analyses. The model has a theoretical sedimentation coefficient that matches well with the experimentally derived value from sedimentation velocity analytical ultracentrifugation. Additionally, the EM model has similarities to models calculated independently by rigid-body modelling to small-angle X-ray scattering (SAXS) data and extracted in silico from the β-crustacyanin crystal lattice. Theoretical X-ray scattering from each of these models is in reasonable agreement with the experimental SAXS data and together suggest an overall design for the α-crustacyanin assembly

Modulated structure formation in demixing paraffin blends

CERN Document Server

Gilbert, E P

2002-01-01

Small angle scattering (SANS and SAXS) and differential scanning calorimetry have been measured from C sub 2 sub 8 :C sub 3 sub 6 normal paraffin mixtures of varying composition quenched from the melt. Satellite peaks are observed in the SAXS whose offset in Q, relative to Bragg diffraction peaks associated with the average structure, are composition dependent. The offset is close to the position of the most intense peak observed in SANS. Scattering from the quenched structures is consistent with a correlated displacement and substitutional disorder model yielding modulations that are incommensurate with the average lattice. DSC shows an additional endotherm in the mixtures that is not present in the pure components and is associated with this superstructure formation. (orig.)

Adaptive robust polynomial regression for power curve modeling with application to wind power forecasting

DEFF Research Database (Denmark)

Xu, Man; Pinson, Pierre; Lu, Zongxiang

2016-01-01

of the lack of time adaptivity. In this paper, a refined local polynomial regression algorithm is proposed to yield an adaptive robust model of the time-varying scattered power curve for forecasting applications. The time adaptivity of the algorithm is considered with a new data-driven bandwidth selection......Wind farm power curve modeling, which characterizes the relationship between meteorological variables and power production, is a crucial procedure for wind power forecasting. In many cases, power curve modeling is more impacted by the limited quality of input data rather than the stochastic nature...... of the energy conversion process. Such nature may be due the varying wind conditions, aging and state of the turbines, etc. And, an equivalent steady-state power curve, estimated under normal operating conditions with the intention to filter abnormal data, is not sufficient to solve the problem because...

Measurement of effective atomic number of composite materials using scattering of γ-rays

International Nuclear Information System (INIS)

Singh, M.P.; Sandhu, B.S.; Singh, Bhajan

2007-01-01

In the present experiment, to determine the effective atomic number of composite materials, the scattering of 145 keV γ-rays is studied using a high-resolution HPGe semiconductor detector placed at 70 deg. to the incident beam. The experiment is performed on various elements of different atomic number, 6≤Z≤64, for 145 keV incident photons. The intensity ratio of Rayleigh to Compton scattered peaks, corrected for photo-peak efficiency of the γ-detector and absorption of photons in the target and air, is plotted as a function of atomic number and constituted a fit curve. From this fit curve, the respective effective atomic numbers of the composite materials are determined. The agreement of measured values of effective atomic number with the theory is found to be quite satisfactory

X-ray scattering for the characterization of lyophilized breast tissue samples

International Nuclear Information System (INIS)

Elshemey, Wael M.; Mohamed, Fayrouz S.; Khater, Ibrahim M.

2013-01-01

This work investigates the possibility of characterizing breast cancer by measuring the X-ray scattering profiles of lyophilized excised breast tissue samples. Since X-ray scattering from water-rich tissue is dominated by scattering from water, the removal of water by lyophilization would enhance the characterization process. In the present study, X-ray scattering profiles of 22 normal, 22 malignant and 10 benign breast tissue samples are measured. The cut-offs of scatter diagrams, sensitivity, specificity and diagnostic accuracy of three characterization parameters (full width at half maximum (FWHM) for the peak at 1.1 nm −1 , area under curve (AUC), and ratio of 1st to 2nd scattering peak intensities (I 1 /I 2 %)) are calculated and compared to the data from non-lyophilized samples. Results show increased sensitivity (up to 100%) of the present data on lyophilized breast tissue samples compared to previously reported data for non-lyophilized samples while the specificity (up to 95.4%), diagnostic accuracy (up to 95.4%) and receiver operating characteristic (ROC) curve values (up to 0.9979) for both sets of data are comparable. The present study shows significant differences between normal samples and each of malignant and benign samples. Only subtle differences exist between malignant and benign lyophilized breast tissue samples where FWHM=0.7±0.1 and 0.8±0.3, AUC=1.3±0.2 and 1.4±0.2 and I 1 /I 2 %=44.9±11.0 and 52.4±7.6 for malignant and benign samples respectively. - Highlights: • X-ray scattering profiles of breast tissue samples are acquired. • Three X-ray profile characterization parameters are calculated. • The cut-offs, sensitivity, specificity and diagnostic accuracy are calculated. • They are compared to the data from non-lyophilized samples. • Results show increased sensitivity in case of lyophilized samples

New conformations of linear polyubiquitin chains from crystallographic and solution-scattering studies expand the conformational space of polyubiquitin.

Science.gov (United States)

Thach, Trung Thanh; Shin, Donghyuk; Han, Seungsu; Lee, Sangho

2016-04-01

The conformational flexibility of linkage-specific polyubiquitin chains enables ubiquitylated proteins and their receptors to be involved in a variety of cellular processes. Linear or Met1-linked polyubiquitin chains, associated with nondegradational cellular signalling pathways, have been known to adopt multiple conformations from compact to extended conformations. However, the extent of such conformational flexibility remains open. Here, the crystal structure of linear Ub2 was determined in a more compact conformation than that of the previously known structure (PDB entry 3axc). The two structures differ significantly from each other, as shown by an r.m.s.d. between C(α) atoms of 3.1 Å. The compactness of the linear Ub2 structure in comparison with PDB entry 3axc is supported by smaller values of the radius of gyration (Rg; 18 versus 18.9 Å) and the maximum interatomic distance (Dmax; 55.5 versus 57.8 Å). Extra intramolecular hydrogen bonds formed among polar residues between the distal and proximal ubiquitin moieties seem to contribute to stabilization of the compact conformation of linear Ub2. An ensemble of three semi-extended and extended conformations of linear Ub2 was also observed by small-angle X-ray scattering (SAXS) analysis in solution. In addition, the conformational heterogeneity in linear polyubiquitin chains is clearly manifested by SAXS analyses of linear Ub3 and Ub4: at least three distinct solution conformations are observed in each chain, with the linear Ub3 conformations being compact. The results expand the extent of conformational space of linear polyubiquitin chains and suggest that changes in the conformational ensemble may be pivotal in mediating multiple signalling pathways.

Measurement of rocking curve wings at high x-ray energies

International Nuclear Information System (INIS)

Chapman, D.; Hastings, J.; Moulin, H.; Siddons, D.P.; Garrett, R.F.; Nachaliel, E.; Dilmanian, F.A.

1991-01-01

Measurements done recently at the NSLS have indicated that the level of intensity found in the wings of diffraction peaks from silicon at higher x-ray energies (>20keV) far exceeds the value which would be predicted based on the dynamical theory. We have measured Si(220) double crystal rocking curves at the 40keV fundamental and harmonics with various crystal scattering geometries: Bragg-Bragg, Laue-Bragg, Laue-Lauel. The comparison of the Bragg and Laue case diffraction geometries was done to determine scattering volume effects. Comparisons with dynamical theory calculations will be discussed. These measurements have been carried out in order to assess the level of harmonic contamination which will be present from a double crystal monochromator being designed for the X17 Superconducting Wiggler Beamline

Electromagnetic wave scattering from a forest or vegetation canopy - Ongoing research at the University of Texas at Arlington

Science.gov (United States)

Karam, Mostafa A.; Amar, Faouzi; Fung, Adrian K.

1993-01-01

The Wave Scattering Research Center at the University of Texas at Arlington has developed a scattering model for forest or vegetation, based on the theory of electromagnetic-wave scattering in random media. The model generalizes the assumptions imposed by earlier models, and compares well with measurements from several forest canopies. This paper gives a description of the model. It also indicates how the model elements are integrated to obtain the scattering characteristics of different forest canopies. The scattering characteristics may be displayed in the form of polarimetric signatures, represented by like- and cross-polarized scattering coefficients, for an elliptically-polarized wave, or in the form of signal-distribution curves. Results illustrating both types of scattering characteristics are given.

Isolation and initial structural characterization of a 27 kDa protein from Zingiber officinale

Science.gov (United States)

Rasheed, Saima; Malik, Shoaib Ahmad; Falke, Sven; Arslan, Ali; Fazel, Ramin; Schlüter, Hartmut; Betzel, Christian; Choudhary, M. Iqbal

2018-03-01

Zingiber officinale Roscoe (Ginger) is a widely used traditional medicinal plant (for different ailments such as arthritis, constipation, and hypertension). This article describes the isolation and characterization of a so far unknown protein from ginger rhizomes applying ion exchange, affinity, size-exclusion chromatography, small angle X-ray scattering (SAXS), and mass spectrometry techniques. One-dimensional Coomassie-stained SDS-PAGE was performed under non-reducing conditions, showing one band corresponding to approx. 27 kDa. Dynamic light scattering (DLS) analysis of the protein solution revealed monodispersity and a monomeric state of the purified protein. Circular dichroism (CD) spectroscopy strongly indicated a β-sheet-rich protein, and disordered regions. MALDI-TOF-MS, and LC-MS/MS analysis resulted in the identification of 27.29 kDa protein, having 32.13% and 25.34% sequence coverage with Zingipain-1 and 2, respectively. The monomeric state and molecular weight were verified by small angle X-ray scattering (SAXS) studies. An elongated ab-initio model was calculated based on the scattering intensity distribution.

Structural analysis and characterization of synthesized ordered mesoporous silicate (MCM-41) using small angle X-rays scattering and complementary techniques

Science.gov (United States)

Akinlalu, Ademola V.

Mesoporous silicate have widespread potential applications, such as drug delivery, supports for catalysis, selective adsorption and host to guest molecules. Most important in the area of scientific research and industrial applications is their demand due to its extremely high surface areas (> 800m 2g-1) and larger pores with well defined structures. Mesoporous silicate (MCM-41) samples were prepared by hydrothermal method under various chemo-physical conditions and various experimental methods such as small angle X-rays scattering (SAXS), Nitrogen adsorption-desorption analysis at 77 K, Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) were employed to investigate the changes in the structural morphology and subtle lattice parameter changes. With regards to the subtle changes in the structural characteristics of the synthesized mesoporous silicate, we seek to understand the electron density function changes as the synthesis parameter are varied from low molar concentration of ATAB/Si to higher concentration, the system becoming more acidity due to increase in the hydrolysis time of pH regulator as a result of increased production of ethanol and acetic acid and the changes due to extended reaction time. This Ph.D. research tries to understand the influence of various parameters like surfactant-Si molar ratio, reaction time, and the hydrolysis of the pH regulator on the orderliness/disorderliness of the lattice order, lattice spacing and electron density function. The stages during synthesis are carefully selected to better understand where the greater influence on the overall structural morphology exist so as to be able to ne tune this parameter for any desired specification and application. The SAXS measurement were conducted on a HECUS S3-Micro X-ray system at Rensselaer Polytechnic Institute, Troy, NY. while the data evaluation and visualization were carried in 3DView 4.2 and EasySWAXS software. The electron density functions

RheoSAXS studies of anisotropic complex fluids under shear

International Nuclear Information System (INIS)

Silva, J P de; Petermann, D; Kasmi, B; Imperor-Clerc, M; Davidson, P; Pansu, B; Meneau, F; Perez, J; Paineau, E; Bihannic, I; Michot, L J; Baravian, C

2010-01-01

We discuss the application of in-situ rheological small angle X-ray scattering experiments to the study of complex fluids under shear, implemented using custom Couette cylinder rheometers mounted on the SWING beamline of the SOLEIL Synchrotron. We discuss several applications of this technique to the study of phase transitions in nanoparticle doped liquid crystals and shear alignment of clay suspensions. The concurrent capture of rheological and scattering data provides vital information that relates macroscopic properties such as viscosity to the microstructure of the fluid.

Conservatism of ASME KIR-reference curve with respect to crack arrest

International Nuclear Information System (INIS)

Wallin, K.; Rintamaa, R.; Nagel, G.

1999-01-01

The conservatism of the RT NDT temperature indexing parameter and the ASME K IR -reference curve with respect to crack arrest toughness, has been evaluated. Based on an analysis of the original ASME K Ia data, it was established that inherently, the ASME K IR -reference curve corresponds to an overall 5% lower bound curve with respect to crack arrest. It was shown that the scatter of crack arrest toughness is essentially material independent and has a standard deviation of 18% and the temperature dependence of K Ia has the same form as predicted by the master curve for crack initiation toughness. The 'built in' offset between the mean 100 MPa√(m) crack arrest temperature, TK Ia , and RT NDT is 38 C (TK Ia =RT NDT +38 C) and the experimental relation between TK Ia and NDT is, TK Ia =NDT+28 C. The K IR -reference curve using NDT as reference temperature will be conservative with respect to the general 5% lower bound K Ia(5%) -curve, with a 75% confidence. The use of RT NDT , instead of NDT, will generally increase the degree of conservatism, both for non-irradiated as well as irradiated materials, close to a 95% confidence level. This trend is pronounced for materials with Charpy-V upper shelf energies below 100 J. It is shown that the K IR -curve effectively constitutes a deterministic lower bound curve for crack arrest. The findings are valid both for nuclear pressure vessel plates, forgings and welds. (orig.)

Conservatism of ASME KIR-reference curve with respect to crack arrest

International Nuclear Information System (INIS)

Wallin, K.; Rintamaa, R.; Nagel, G.

2001-01-01

The conservatism of the RT NDT temperature indexing parameter and the ASME K IR -reference curve with respect to crack arrest toughness, has been evaluated. Based on an analysis of the original ASME K Ia data, it was established that inherently, the ASME K IR -reference curve corresponds to an overall 5% lower bound curve with respect to crack arrest. It was shown that the scatter of crack arrest toughness is essentially material independent and has a standard deviation (S.D.) of 18% and the temperature dependence of K Ia has the same form as predicted by the master curve for crack initiation toughness. The 'built in' offset between the mean 100 MPa√m crack arrest temperature, TK Ia , and RT NDT is 38 deg. C (TK Ia =RT NDT +38 deg. C) and the experimental relation between TK Ia and NDT is, TK Ia =NDT+28 deg. C. The K IR -reference curve using NDT as reference temperature will be conservative with respect to the general 5% lower bound K Ia(5%) -curve, with a 75% confidence. The use of RT NDT , instead of NDT, will generally increase the degree of conservatism, both for non-irradiated as well as irradiated materials, close to a 95% confidence level. This trend is pronounced for materials with Charpy-V upper shelf energies below 100 J. It is shown that the K IR -curve effectively constitutes a deterministic lower bound curve for crack arrest The findings are valid both for nuclear pressure vessel plates, forgings and welds

Lagrangian Curves on Spectral Curves of Monopoles

International Nuclear Information System (INIS)

Guilfoyle, Brendan; Khalid, Madeeha; Ramon Mari, Jose J.

2010-01-01

We study Lagrangian points on smooth holomorphic curves in TP 1 equipped with a natural neutral Kaehler structure, and prove that they must form real curves. By virtue of the identification of TP 1 with the space LE 3 of oriented affine lines in Euclidean 3-space, these Lagrangian curves give rise to ruled surfaces in E 3 , which we prove have zero Gauss curvature. Each ruled surface is shown to be the tangent lines to a curve in E 3 , called the edge of regression of the ruled surface. We give an alternative characterization of these curves as the points in E 3 where the number of oriented lines in the complex curve Σ that pass through the point is less than the degree of Σ. We then apply these results to the spectral curves of certain monopoles and construct the ruled surfaces and edges of regression generated by the Lagrangian curves.

Raman scattering by hot and thermal polaritons in crystal quartz

Energy Technology Data Exchange (ETDEWEB)

Bogani, F.; Colocci, M.; Neri, M.; Querzoli, R.

1984-11-01

Nonlinear mixing of IR and visible radiation, i.e. coherent Raman scattering by polaritons driven by a CO/sub 2/ laser, has been used to obtain the dispersion curve and its width in q-space of the polariton associated to the E-phonon at 1065 cm/sup -1/ in crystal quartz. It is shown in this paper that a direct method to determine independently, with high precision, the refractive index and absorbance of a crystal can be obtained in this way. The results are compared with accurate data obtained from Raman scattering by polaritions in thermal equilibrium and very good agreement is found between the two measurements. It is finally shown that nonlinear-mixing techniques turn out to be completely consistent with the simple picture of scattering of light by hot polaritons.

The small angle x-ray scattering of globular proteins in solution during heat denaturation

Science.gov (United States)

Banuelos, Jose; Urquidi, Jacob

2008-10-01

The ability of proteins to change their conformation in response to changes in their environment has consequences in biological processes like metabolism, chemical regulation in cells, and is believed to play a role in the onset of several neurodegenerative diseases. Factors such as a change in temperature, pressure, and the introduction of ions into the aqueous environment of a protein can give rise to the folding/unfolding of a protein. As a protein unfolds, the ratio of nonpolar to polar groups exposed to water changes, affecting a protein's thermodynamic properties. Using small angle x-ray scattering (SAXS), we are currently studying the intermediate protein conformations that arise during the folding/unfolding process as a function of temperature for five globular proteins. Trends in the observed intermediate structures of these globular proteins, along with correlations with data on protein thermodynamics may help elucidate shared characteristics between all proteins in the folding/unfolding process. Experimental design considerations will be discussed and preliminary results for some of these systems will be presented.

Observations of the transient X-ray pulsar EXO 053109-6609.2 with ASCA, BeppoSAX and XMM-Newton

International Nuclear Information System (INIS)

Naik, S.; Paul, B.; Agrawal, P.C.; Jaaffery, S.N.A.

2004-01-01

We report timing and spectral properties of the transient X-ray pulsar EXO 053109-6609.2 using observations carried out with ASCA, BeppoSAX, and XMM-Newton observatories. Pulse period measurements of the source show a monotonic spin-up trend since 1996. The pulse profile is found to have a strong luminosity dependence, a single peaked profile at low luminosity that changes to a double peaked profile at high luminosity. The X-ray spectrum is described by a simple power-law model with photon index in the range of 0.2-0.8. A soft excess over the power-law continuum is also detected from XMM-Newton observation

Characterization of an in-vacuum PILATUS 1M detector.

Science.gov (United States)

Wernecke, Jan; Gollwitzer, Christian; Müller, Peter; Krumrey, Michael

2014-05-01

A dedicated in-vacuum X-ray detector based on the hybrid pixel PILATUS 1M detector has been installed at the four-crystal monochromator beamline of the PTB at the electron storage ring BESSY II in Berlin, Germany. Owing to its windowless operation, the detector can be used in the entire photon energy range of the beamline from 10 keV down to 1.75 keV for small-angle X-ray scattering (SAXS) experiments and anomalous SAXS at absorption edges of light elements. The radiometric and geometric properties of the detector such as quantum efficiency, pixel pitch and module alignment have been determined with low uncertainties. The first grazing-incidence SAXS results demonstrate the superior resolution in momentum transfer achievable at low photon energies.

Indirect transformation in reciprocal space: desmearing of small-angle scattering data from partially ordered systems

International Nuclear Information System (INIS)

Glatter, O.; Gruber, K.

1993-01-01

Indirect Fourier transformation is a widely used technique for the desmearing of instrumental broadening effects, for data smoothing and for Fourier transformation of small-angle scattering data. This technique, however, can only be applied to scattering curves with a band-limited Fourier transform, i.e. separated and noninteracting scattering centers. It can therefore not be used for scattering data from partially ordered systems. In this paper, a modified technique for partially ordered systems working in reciprocal space is presented. A peak-recognition technique allows its application to scattering functions with narrow peaks, such as the scattering functions of layered systems like lamellar stacks or strongly interacting particles. Arbitrary geometry effects and wavelength effects can be corrected. Examples of simulations show the merits and limits of this new method. One example shows its applicability to real data. (orig.)

Synchrotron X-ray Scattering Analysis of the Interaction Between Corn Starch and an Exogenous Lipid During Hydrothermal Treatment

Energy Technology Data Exchange (ETDEWEB)

E Hernandez-Hernandez; C Avila-Orta; B Hsiao; j Castro-Rosas; J Gallegos-Infante; J Morales-Castro; L Ochoa-Martinez; C Gomez-Aldapa

2011-12-31

Lipids have an important effect on starch physicochemical properties. There exist few reports about the effect of exogenous lipids on native corn starch structural properties. In this work, a study of the morphological, structural and thermal properties of native corn starch with L-alpha-lysophosphatidylcholine (LPC, the main phospholipid in corn) was performed under an excess of water. Synchrotron radiation, in the form of real-time small and wide-angle X-ray scattering (SAXS/WAXS), was used in order to track structural changes in corn starch, in the presence of LPC during a heating process from 30 to 85 C. When adding LCP, water absorption decreased within starch granule amorphous regions during gelatinization. This is explained by crystallization of the amylose-LPC inclusion complex during gelatinization, which promotes starch granule thermal stability at up to 95 C. Finally, a conceptual model is proposed for explaining the formation mechanism of the starch-LPC complex.

Coacervates of lactotransferrin and β- or κ-casein: structure determined using SAXS.

Science.gov (United States)

de Kruif, C G Kees; Pedersen, JanSkov; Huppertz, Thom; Anema, Skelte G

2013-08-20

Lactotransferrin (LF) is a large globular protein in milk with immune-regulatory and bactericidal properties. At pH 6.5, LF (M = 78 kDa) carries a net (calculated) charge of +21. β-Casein (BCN) and κ-casein (KCN) are part of the casein micelle complex in milk. Both BCN and KCN are amphiphillic proteins with a molar mass of 24 and 19 kDa and carry net charges of -14 and -4, respectively. Both BCN and KCN form soap-like micelles, with 40 and 65 monomers, respectively. The net negative charges are located in the corona of the micelles. On mixing LF with the caseins, coacervates are formed. We analyzed the structure of these coarcervates using SAXS. It was found that LF binds to the corona of the micellar structures, at the charge neutrality point. BCN/LF and KCN/LF ratios at the charge neutrality point were found to be ~1.2 and ~5, respectively. We think that the findings are relevant for the protection mechanism of globular proteins in bodily fluids where unstructured proteins are abundant (saliva). The complexes will prevent docking of enzymes on specific charged groups on the globular protein.

GRB060206 and the quandary of achromatic breaks in afterglow light curves

NARCIS (Netherlands)

Curran, P.A.; van der Horst, A.J.; Wijers, R.A.M.J.; Starling, R.L.C.; Castro-Tirado, A.J.; Fynbo, J.P.U.; Gorosabel, J.; Järvinen, A.S.; Malesani, D.; Rol, E.; Tanvir, N.R.; Wiersema, K.; Burleigh, M.R.; Casewell, S.L.; Dobbie, P.D.; Guziy, S.; Jakobsson, P.; Jelínek, M.; Laursen, P.; Levan, A.J.; Mundell, C.G.; Näränen, J.; Piranomonte, S.

2007-01-01

Gamma-ray burst afterglow observations in the Swift era have a perceived lack of achromatic jet breaks compared with the BeppoSAX era. We present our multi-wavelength analysis of GRB060206 as an illustrative example of how inferences of jet breaks from optical and X-ray data might differ. The

Potential energy curves for the interaction of a low-energy positron with matter: The case He+e{sup +}

Energy Technology Data Exchange (ETDEWEB)

Mohallem, Jose R. [Laboratorio de Atomos e Moleculas Especiais, Departamento de Fisica, ICEx, Universidade Federal de Minas Gerais, P.O. Box 702, 30123-970 Belo Horizonte, MG (Brazil)]. E-mail: rachid@fisica.ufmg.br; Rolim, Flavia [Departamento de Quimica, Universidade de Coimbra, FCT, 3004-535 Coimbra (Portugal)

2007-02-15

In this introductory exploration of the title theme, we treat a positron as a light nucleus and work within the quasi-molecule approximation to obtain, for the first time, adiabatic potential energy curves for its scattering by the He atom. We then show that different elastic and inelastic processes that contribute to the total scattering cross section can be rationalized in molecular terms as dissociation and non-adiabatic couplings. Particularly, some new insights on positronium yielding are presented.

Inelastic neutron scattering from high-density fcc 4He

International Nuclear Information System (INIS)

Thomlinson, W.; Eckert, J.; Shirane, G.

1978-01-01

The phonon dispersion relations in high-density crystals of fcc 4 He have been measured along high-symmetry directions by the neutron-inelastic-scattering technique. A recent study of the lattice dynamics of fcc 4 He by Eckert et al. has been extended to cover the fcc phase diagram at pressures below 5 kbar. Molar volumes of 9.03, 9.43, and 9.97 cm 3 /mole have been studied in the temperature range from near the melting curve to near the fcc-hcp transition line. The phonon dispersion relations are in good agreement with a first-order self-consistent phonon theory calculation by Goldman. The observed phonon-group line shapes at large energy and momentum transfers show evidence for multiphonon scattering in agreement with calculations by Glyde. Eckert et al. reported extremely large anharmonic isochoric temperature shifts of the phonon energies. The present work studied the shifts as a function of molar volume and temperature. Mode-Grueneisen-parameter dispersion curves have been measured using the present data and earlier measurements at lower density in the fcc phase by Traylor et al. Macroscopic Grueneisen parameters have been calculated from the phonon density of states obtained from the data

Isothermal structural evolution of SnO2 monolithic porous xerogels

International Nuclear Information System (INIS)

Brito, G.E.S.; Pulcinelli, S.H.; Santilli, C.V.; Craievich, A.F.

1997-01-01

Monolithic samples of SnO 2 xerogel were produced by careful control of the gelation and drying steps of material preparation. In these samples, small and nanoporous aggregates stick together, yielding a monolithic (nonpowdered) material. The material was analyzed by in situ small-angle X-ray scattering (SAXS) during isothermal treatment at temperatures ranging from 473 to 773 K. At 473 K, the SAXS intensity does not change significantly with time. All experimental scattering intensity functions for T > 473 K are composed of two wide peaks, which evolve with increasing time. Each of them was associated with one of the modes of a bimodal distribution of pore sizes corresponding to a fine (intra-aggregate) and a coarse (inter-aggregate) porosity. The SAXS intensities of the maxima of both peaks increase with increasing treatment time, while the position of their maxima, associated with an average correlation distance, decreases. The time dependences of the SAXS intensity corresponding to both families of pores qualitatively agree with those expected for a two-phase separating system exhibiting dynamic scaling properties. The time evolutions of the several moments of the structure function of samples heat treated at 773 K exhibit a good quantitative agreement with the theory of dynamic scaling for systems evolving by a coagulation mechanism. The kinetic parameters are the same for both peaks, indicating that the same mechanism is responsible for the structural evolution of both families of pores. (orig.)

A study on the measurement of effective energy of scattering X-rays

International Nuclear Information System (INIS)

Oogama, Noboru; Fujimoto, Nobuhisa; Nishitani, Motohiro; Yamada, Katsuhiko

1995-01-01

Only a few studies have been reported on the measurement and evaluation of the effective energy of scattering X-rays using an ionization chamber. The reason for this is due to the difficulty in accurately measuring attenuation curve in scattering X-rays lacking any directional properties. We could come up with a new method for calculating the effective energy of scattering X-rays by utilizing their spectra data. First, for analysing the accuracy of our calculation method with using primary X-rays, a comparison was made of calculated values of the effective energy obtained by our calculation method with the measurement values obtained using an ionization chamber. The results gave the calculated values agreeing with the measurement values within a maximum error of 2%, and this method was very helpful in measuring the effective energy of the scattering X-rays. Consequently, this method was capable of measuring the effective energy of scattering X-rays in the following parameters: X-ray tube voltage, scattering angle and size of scatterer. In conclusion, it is considered that our method could solve the present difficulty regarding the measurement of effective energy of the scattering X-rays, and provided a useful procedure concerning the study of radiation protection. (author)

SPOTTED STAR LIGHT CURVES WITH ENHANCED PRECISION

International Nuclear Information System (INIS)

Wilson, R. E.

2012-01-01

The nearly continuous timewise coverage of recent photometric surveys is free of the large gaps that compromise attempts to follow starspot growth and decay as well as motions, thereby giving incentive to improve computational precision for modeled spots. Due to the wide variety of star systems in the surveys, such improvement should apply to light/velocity curve models that accurately include all the main phenomena of close binaries and rotating single stars. The vector fractional area (VFA) algorithm that is introduced here represents surface elements by small sets of position vectors so as to allow accurate computation of circle-triangle overlap by spherical geometry. When computed by VFA, spots introduce essentially no noticeable scatter in light curves at the level of one part in 10,000. VFA has been put into the Wilson-Devinney light/velocity curve program and all logic and mathematics are given so as to facilitate entry into other such programs. Advantages of precise spot computation include improved statistics of spot motions and aging, reduced computation time (intrinsic precision relaxes needs for grid fineness), noise-free illustration of spot effects in figures, and help in guarding against false positives in exoplanet searches, where spots could approximately mimic transiting planets in unusual circumstances. A simple spot growth and decay template quantifies time profiles, and specifics of its utilization in differential corrections solutions are given. Computational strategies are discussed, the overall process is tested in simulations via solutions of synthetic light curve data, and essential simulation results are described. An efficient time smearing facility by Gaussian quadrature can deal with Kepler mission data that are in 30 minute time bins.

Influence of 1,2-PB matrix cross-linking on structure and properties of selectively etched 1,2-PB-b-PDMS block copolymers

DEFF Research Database (Denmark)

Guo, Fengxiao; Andreasen, Jens Wenzel; Vigild, Martin Etchells

2007-01-01

of the cross-linked samples in toluene was converted into a degree of cross-linking following the Flory scheme; a simple relation between the Flory cross-linking degree and the fraction of consumed double bonds during the cross-linking reaction followed. The structure of the block copolymer at different stages...... of preparation was characterized by small-angle X-ray scattering (SAXS). In addition, scanning electron microscopy (SEM) gave direct images of the nanoporous polymer structure. Nanocavities are accessible to methanol, and observations of methanol uptake were combined with structural information from SAXS...

Phase separation and nanocrystal formation in Al-based metallic glasses

International Nuclear Information System (INIS)

Antonowicz, Jerzy

2007-01-01

Nanocrystallization in a group of Al-RE and Al-RE-TM (RE = rare earth, TM = transition metal) melt-spun amorphous alloys was studied using in situ small- and wide-angle X-ray scattering techniques (SAXS/WAXS) and transmission electron microscopy (TEM). The SAXS/WAXS measurements were carried out during isothermal annealing at temperatures close to crystallization point. A continuously growing interference maximum shifting progressively toward lower angles was found to develop in SAXS regime. Simultaneously taken WAXS spectra reveal formation of the primary fcc-Al nanocrystalline phase. The presence of the SAXS signal maximum indicates the spatial correlation between the compositional fluctuations. The peak position decay is an evidence of an increase of the fluctuation spacing characteristic for the coarsening stage of phase separation. The SAXS/WAXS data analysis indicates that amorphous phase decomposition triggers and controls the fcc-Al nanocrystalline phase formation. The glassy phase initially decomposes into Al-rich and RE-rich regions with typical lengths scale of about 10 nm. The nanocrystals nucleate preferentially inside the Al-rich amorphous regions and their growth is constrained by the region size because of the sluggish atomic diffusion in the RE-rich zones. A different crystallization mechanism is demonstrated in Al-Y-Ni-Co glass where WAXS spectra show formation of the fcc-Al primary phase but no interference peak in SAXS regime was found

Measurements of Positronium Formation Cross Sections for Positron-Kr, Xe Scattering

Science.gov (United States)

Kauppila, W. E.; Kwan, C. K.; Li, H.; Stein, T. S.; Zhou, S.

1997-04-01

Our experimental approach(S. Zhou et al., Phys. Rev. Lett. 73, 236 (1994).) for measuring Ps formation cross sections (Q_Ps) involves passing a variable energy positron beam through a gas scattering cell and detecting the 511 keV annihilation gamma rays resulting from the decay of para-Ps and from the interaction of ortho-Ps with the walls of the scattering cell. It is found that the Q_Ps curves for both Kr and Xe rise rapidly from their formation threshold energies of 7.2 and 5.3 eV, reach maxima within about 10 eV of their thresholds and then decrease to become rather small (less than 10% of the peak heights) above 100 eV. At the maxima Q_Ps accounts for more than 50% of the total scattering cross sections. There is some evidence of possible small scale structure in the Q_Ps curves between 10 and 100 eV. The present results are consistent with the prior measurements of Diana et al.( L.M. Diana et al., in "Atomic Physics with Positrons", edited by J.W. Humberston and E.A.G. Armour (Plenum, New York and London, 1987), p. 55; and in "Positron Annihilation", edited by L. Dorikens-Vanpraet et al. (World Scientific, Singapore, 1989), p. 311.) from near threshold to 70 eV for Kr and from 15 to 100 eV for Xe.

Comparison of neutron scattering, gravimetric and tensiometric methods for measuring soil water content in the field

International Nuclear Information System (INIS)

Jat, R.L.; Das, D.K.; Naskar, G.C.

1975-01-01

Water content of a sandy clay loam soil was measured by neutron scattering, gravimetric and tensiometric methods. Tensiometric measurement based on laboratory moisture retention curve gave comparatively higher moisture content than those obtained by other methods. No significant differences were observed among neutron meter, gravimetric and tensiometric measurement based on field calibration curve. Though for irrigation purposes all the methods can be used equally, use of tensiometric method with field calibration curve is suggested for easy and more accurate soil water content measurement where neutron meter is not available. (author)

Cosmological parameter uncertainties from SALT-II type Ia supernova light curve models

International Nuclear Information System (INIS)

Mosher, J.; Sako, M.; Guy, J.; Astier, P.; Betoule, M.; El-Hage, P.; Pain, R.; Regnault, N.; Kessler, R.; Frieman, J. A.; Marriner, J.; Biswas, R.; Kuhlmann, S.; Schneider, D. P.

2014-01-01

We use simulated type Ia supernova (SN Ia) samples, including both photometry and spectra, to perform the first direct validation of cosmology analysis using the SALT-II light curve model. This validation includes residuals from the light curve training process, systematic biases in SN Ia distance measurements, and a bias on the dark energy equation of state parameter w. Using the SN-analysis package SNANA, we simulate and analyze realistic samples corresponding to the data samples used in the SNLS3 analysis: ∼120 low-redshift (z < 0.1) SNe Ia, ∼255 Sloan Digital Sky Survey SNe Ia (z < 0.4), and ∼290 SNLS SNe Ia (z ≤ 1). To probe systematic uncertainties in detail, we vary the input spectral model, the model of intrinsic scatter, and the smoothing (i.e., regularization) parameters used during the SALT-II model training. Using realistic intrinsic scatter models results in a slight bias in the ultraviolet portion of the trained SALT-II model, and w biases (w input – w recovered ) ranging from –0.005 ± 0.012 to –0.024 ± 0.010. These biases are indistinguishable from each other within the uncertainty; the average bias on w is –0.014 ± 0.007.

Cosmological Parameter Uncertainties from SALT-II Type Ia Supernova Light Curve Models

Energy Technology Data Exchange (ETDEWEB)

Mosher, J. [Pennsylvania U.; Guy, J. [LBL, Berkeley; Kessler, R. [Chicago U., KICP; Astier, P. [Paris U., VI-VII; Marriner, J. [Fermilab; Betoule, M. [Paris U., VI-VII; Sako, M. [Pennsylvania U.; El-Hage, P. [Paris U., VI-VII; Biswas, R. [Argonne; Pain, R. [Paris U., VI-VII; Kuhlmann, S. [Argonne; Regnault, N. [Paris U., VI-VII; Frieman, J. A. [Fermilab; Schneider, D. P. [Penn State U.

2014-08-29

We use simulated type Ia supernova (SN Ia) samples, including both photometry and spectra, to perform the first direct validation of cosmology analysis using the SALT-II light curve model. This validation includes residuals from the light curve training process, systematic biases in SN Ia distance measurements, and a bias on the dark energy equation of state parameter w. Using the SN-analysis package SNANA, we simulate and analyze realistic samples corresponding to the data samples used in the SNLS3 analysis: ~120 low-redshift (z < 0.1) SNe Ia, ~255 Sloan Digital Sky Survey SNe Ia (z < 0.4), and ~290 SNLS SNe Ia (z ≤ 1). To probe systematic uncertainties in detail, we vary the input spectral model, the model of intrinsic scatter, and the smoothing (i.e., regularization) parameters used during the SALT-II model training. Using realistic intrinsic scatter models results in a slight bias in the ultraviolet portion of the trained SALT-II model, and w biases (w (input) – w (recovered)) ranging from –0.005 ± 0.012 to –0.024 ± 0.010. These biases are indistinguishable from each other within the uncertainty, the average bias on w is –0.014 ± 0.007.

SCT: a suite of programs for comparing atomistic models with small-angle scattering data.

Science.gov (United States)

Wright, David W; Perkins, Stephen J

2015-06-01

Small-angle X-ray and neutron scattering techniques characterize proteins in solution and complement high-resolution structural studies. They are of particular utility when large proteins cannot be crystallized or when the structure is altered by solution conditions. Atomistic models of the averaged structure can be generated through constrained modelling, a technique in which known domain or subunit structures are combined with linker models to produce candidate global conformations. By randomizing the configuration adopted by the different elements of the model, thousands of candidate structures are produced. Next, theoretical scattering curves are generated for each model for trial-and-error fits to the experimental data. From these, a small family of best-fit models is identified. In order to facilitate both the computation of theoretical scattering curves from atomistic models and their comparison with experiment, the SCT suite of tools was developed. SCT also includes programs that provide sequence-based estimates of protein volume (either incorporating hydration or not) and add a hydration layer to models for X-ray scattering modelling. The original SCT software, written in Fortran, resulted in the first atomistic scattering structures to be deposited in the Protein Data Bank, and 77 structures for antibodies, complement proteins and anionic oligosaccharides were determined between 1998 and 2014. For the first time, this software is publicly available, alongside an easier-to-use reimplementation of the same algorithms in Python. Both versions of SCT have been released as open-source software under the Apache 2 license and are available for download from https://github.com/dww100/sct.

Monopole scattering with a twist

International Nuclear Information System (INIS)

Houghton, C.J.; Sutcliffe, P.M.

1996-01-01

By imposing certain combined inversion and rotation symmetries on the rational maps for SU(2) BPS monopoles we construct geodesics in the monopole moduli space. In the moduli space approximation these geodesics describe a novel kind of monopole scattering. During these scattering processes axial symmetry is instantaneously attained and, in some, monopoles with the symmetries of the regular solids are formed. The simplest example corresponds to a charge three monopole invariant under a combined inversion and 90 circle rotation symmetry. In this example three well-separated collinear unit charge monopoles coalesce to form first a tetrahedron, then a torus, then the dual tetrahedron and finally separate again along the same axis of motion. We explicitly construct the spectral curves in this case and use a numerical ADHMN construction to compute the energy density at various times during the motion. We find that the dynamics of the zeros of the Higgs field is extremely rich and we discover a new phenomenon; there exist charge k SU(2) BPS monopoles with more than k zeros of the Higgs field. (orig.)

A Combined SAXS/SANS Study for the in Situ Characterization of Ligand Shells on Small Nanoparticles: The Case of ZnO.

Science.gov (United States)

Schindler, T; Schmiele, M; Schmutzler, T; Kassar, T; Segets, D; Peukert, W; Radulescu, A; Kriele, A; Gilles, R; Unruh, T

2015-09-22

ZnO nanoparticles (NPs) have great potential for their use in, e.g., thin film solar cells due to their electro-optical properties adjustable on the nanoscale. Therefore, the production of well-defined NPs is of major interest. For a targeted production process, the knowledge of the stabilization layer of the NPs during and after their formation is of particular importance. For the study of the stabilizer layer of ZnO NPs prepared in a wet chemical synthesis from zinc acetate, only ex situ studies have been performed so far. An acetate layer bound to the surface of the dried NPs was found; however, an in situ study which addresses the stabilizing layer surrounding the NPs in a native dispersion was missing. By the combination of small angle scattering with neutrons and X-rays (SANS and SAXS) for the same sample, we are now able to observe the acetate shell in situ for the first time. In addition, the changes of this shell could be followed during the ripening process for different temperatures. With increasing size of the ZnO core (d(core)) the surrounding shell (d(shell)) becomes larger, and the acetate concentration within the shell is reduced. For all samples, the shell thickness was found to be larger than the maximum extension of an acetate molecule with acetate concentrations within the shell below 50 vol %. Thus, there is not a monolayer of acetate molecules that covers the NPs but rather a swollen shell of acetate ions. This shell is assumed to hinder the growth of the NPs to larger macrostructures. In addition, we found that the partition coefficient μ between acetate in the shell surrounding the NPs and the total amount of acetate in the solution is about 10% which is in good agreement with ex situ data determined by thermogravimetric analysis.

Alloy scattering dependence of electron transport in AlGaN

International Nuclear Information System (INIS)

Yarar, Z.; Ozdemir, M.

2010-01-01

The electron transport and velocity characteristics in AlGaN are examined using an ensemble Monte Carlo simulation method. A three valley band structure model where nonparabolicity effects are considered in all valleys is used for Monte Carlo calculations. All of the major electron scattering interactions like acoustic and optical phonon, intervaley, ionized impurity and alloy disorder scatterings are included in the calculations. The velocity-applied electric field characteristics are analyzed as a function of Al molar fraction and temperature in the ranges of x=0.1 to x=0.5 and 77 K to 500 K, respectively. The velocity overshoot is clearly observed and the population of valleys seems well-matched with the occupancy of valleys in AlGaN. The results of electron steady state velocity-field curves are found that the alloy disorder scattering has important effects on the electron transport characteristics of AlGaN.

Application of new synchrotron powder diffraction techniques to anomalous scattering from glasses

International Nuclear Information System (INIS)

Beno, M.A.; Knapp, G.S.; Armand, P.; Price, D.L.; Saboungi, M.

1995-01-01

We have applied two synchrotron powder diffraction techniques to the measurement of high quality anomalous scattering diffraction data for amorphous materials. One of these methods, which uses a curved perfect crystal analyzer to simultaneously diffract multiple powder lines into a position sensitive detector has been shown to possess high resolution, low background, and very high counting rates. This data measurement technique provides excellent energy resolution while minimizing systematic errors resulting from detector nonlinearity. Anomalous scattering data for a Cesium Germanate glass collected using this technique will be presented. The second powder diffraction technique uses a flat analyzer crystal to deflect multiple diffraction lines out of the equatorial plane. Calculations show that this method possesses sufficient energy resolution for anomalous scattering experiments when a perfect crystal analyzer is used and is experimentally much simpler. Future studies will make use of a rapid sample changer allowing the scattering from the sample and a standard material (a material not containing the anomalous scatterer) to be measured alternately at each angle, reducing systematic errors due to beam instability or sample misalignment

LIGHT SCATTERING FROM EXOPLANET OCEANS AND ATMOSPHERES

International Nuclear Information System (INIS)

Zugger, M. E.; Kane, T. J.; Kasting, J. F.; Williams, D. M.; Philbrick, C. R.

2010-01-01

Orbital variation in reflected starlight from exoplanets could eventually be used to detect surface oceans. Exoplanets with rough surfaces, or dominated by atmospheric Rayleigh scattering, should reach peak brightness in full phase, orbital longitude (OL) = 180 0 , whereas ocean planets with transparent atmospheres should reach peak brightness in crescent phase near OL = 30 0 . Application of Fresnel theory to a planet with no atmosphere covered by a calm ocean predicts a peak polarization fraction of 1 at OL = 74 0 ; however, our model shows that clouds, wind-driven waves, aerosols, absorption, and Rayleigh scattering in the atmosphere and within the water column dilute the polarization fraction and shift the peak to other OLs. Observing at longer wavelengths reduces the obfuscation of the water polarization signature by Rayleigh scattering but does not mitigate the other effects. Planets with thick Rayleigh scattering atmospheres reach peak polarization near OL = 90 0 , but clouds and Lambertian surface scattering dilute and shift this peak to smaller OL. A shifted Rayleigh peak might be mistaken for a water signature unless data from multiple wavelength bands are available. Our calculations suggest that polarization alone may not positively identify the presence of an ocean under an Earth-like atmosphere; however, polarization adds another dimension which can be used, in combination with unpolarized orbital light curves and contrast ratios, to detect extrasolar oceans, atmospheric water aerosols, and water clouds. Additionally, the presence and direction of the polarization vector could be used to determine planet association with the star, and constrain orbit inclination.

Thermodynamic and kinetic aspects of coassembly of PEO-PMAA block copolymer and DPCl surfactants into ordered nanoparticles in aqueous solutions studied by ITC, NMR, and time-resolved SAXS techniques

Czech Academy of Sciences Publication Activity Database

Uchman, M.; Gradzielski, M.; Angelov, Borislav; Tošner, Z.; Oh, J.; Chang, T.; Štěpánek, M.; Procházka, K.

2013-01-01

Roč. 46, č. 6 (2013), s. 2172-2181 ISSN 0024-9297 R&D Projects: GA ČR GAP208/10/0353; GA ČR GCP205/11/J043 Institutional support: RVO:61389013 Keywords : isothermal titration calorimetry * SAXS * soft matter Subject RIV: CD - Macromolecular Chemistry Impact factor: 5.927, year: 2013

Multi-MW wind turbine power curve measurements using remote sensing instruments – the first Høvsøre campaign

DEFF Research Database (Denmark)

Wagner, Rozenn; Courtney, Michael

curve significantly. Two LiDARs and a SoDAR are used to measure the wind profile in front of a wind turbine. These profiles are used to calculate the equivalent wind speed. LiDAR are found to be more accurate than SoDAR and therefore more suitable for power performance measurement. The equivalent wind...... that used of the equivalent wind speed at least results in a power curve with no more scatter than using the conventional method....

Structural aspects of magnetic fluid stabilization in aqueous agarose solutions

Energy Technology Data Exchange (ETDEWEB)

Nagornyi, A.V. [Joint Institute for Nuclear Research, Dubna (Russian Federation); Taras Shevchenko National University of Kyiv, Kyiv (Ukraine); Petrenko, V.I., E-mail: vip@nf.jinr.ru [Joint Institute for Nuclear Research, Dubna (Russian Federation); Taras Shevchenko National University of Kyiv, Kyiv (Ukraine); Avdeev, M.V. [Joint Institute for Nuclear Research, Dubna (Russian Federation); Yelenich, O.V.; Solopan, S.O.; Belous, A.G. [V.I.Vernadsky Institute of General and Inorganic Chemistry of the Ukrainian NAS, Kyiv (Ukraine); Gruzinov, A.Yu. [National Research Centre “Kurchatov Institute”, Moscow (Russian Federation); Ivankov, O.I. [Joint Institute for Nuclear Research, Dubna (Russian Federation); Institute for Safety Problems of Nuclear Power Plants of the Ukrainian NAS, Kyiv (Ukraine); Bulavin, L.A. [Taras Shevchenko National University of Kyiv, Kyiv (Ukraine); Institute for Safety Problems of Nuclear Power Plants of the Ukrainian NAS, Kyiv (Ukraine)

2017-06-01

Structure characterization of magnetic fluids (MFs) synthesized by three different methods in aqueous solutions of agarose was done by means of small-angle neutron (SANS) and synchrotron X-ray scattering (SAXS). The differences in the complex aggregation observed in the studied magnetic fluids were related to different stabilizing procedures of the three kinds of MFs. The results of the analysis of the scattering (mean size of single polydisperse magnetic particles, fractal dimensions of the aggregates) are consistent with the data of transmission electron microscopy (TEM). - Highlights: • MFs synthesized by three different methods in agarose solution were studied. • all MFs are agglomerated colloidal systems whose structures are nevertheless stable in time. • differences in the complex aggregation were observed in the studied magnetic fluids. • results of the SAXS and SANS analysis are consistent with TEM data.

Comparison of ductile-to-brittle transition curve fitting approaches

International Nuclear Information System (INIS)

Cao, L.W.; Wu, S.J.; Flewitt, P.E.J.

2012-01-01

Ductile-to-brittle transition (DBT) curve fitting approaches are compared over the transition temperature range for reactor pressure vessel steels with different kinds of data, including Charpy-V notch impact energy data and fracture toughness data. Three DBT curve fitting methods have been frequently used in the past, including the Burr S-Weibull and tanh distributions. In general there is greater scatter associated with test data obtained within the transition region. Therefore these methods give results with different accuracies, especially when fitting to small quantities of data. The comparison shows that the Burr distribution and tanh distribution can almost equally fit well distributed and large data sets extending across the test temperature range to include the upper and lower shelves. The S-Weibull distribution fit is poor for the lower shelf of the DBT curve. Overall for both large and small quantities of measured data the Burr distribution provides the best description. - Highlights: ► Burr distribution offers a better fit than that of a S-Weibull and tanh fit. ► Burr and tanh methods show similar fitting ability for a large data set. ► Burr method can fit sparse data well distributed across the test temperature. ► S-Weibull method cannot fit the lower shelf well and show poor fitting quality.

Study of the effects of photoelectron statistics on Thomson scattering data

International Nuclear Information System (INIS)

Hart, G.W.; Levinton, F.M.; McNeill, D.H.

1986-01-01

A computer code has been developed which simulates a Thomson scattering measurement, from the counting statistics of the input channels through the mathematical analysis of the data. The scattered and background signals in each of the wavelength channels are assumed to obey Poisson statistics, and the spectral data are fitted to a Gaussian curve using a nonlinear least-squares fitting algorithm. This method goes beyond the usual calculation of the signal-to-noise ratio for the hardware and gives a quantitative measure of the effect of the noise on the final measurement. This method is applicable to Thomson scattering measurements in which the signal-to-noise ratio is low due to either low signal or high background. Thomson scattering data from the S-1 spheromak have been compared to this simulation, and they have been found to be in good agreement. This code has proven to be useful in assessing the effects of counting statistics relative to shot-to-shot variability in producing the observed spread in the data. It was also useful for designing improvements for the S-1 Thomson scattering system, and this method would be applicable to any measurement affected by counting statistics

Application of Master Curve Methodology for Structural Integrity Assessments of Nuclear Components

Energy Technology Data Exchange (ETDEWEB)

Sattari-Far, Iradj [Det Norske Veritas, Stockholm (Sweden); Wallin, Kim [VTT, Esbo (Finland)

2005-10-15

The objective was to perform an in-depth investigation of the Master Curve methodology and also based on this method develop a procedure for fracture assessments of nuclear components. The project has sufficiently illustrated the capabilities of the Master Curve methodology for fracture assessments of nuclear components. Within the scope of this work, the theoretical background of the methodology and its validation on small and large specimens has been studied and presented to a sufficiently large extent, as well as the correlations between the charpy-V data and the Master Curve T{sub 0} reference temperature in the evaluation of fracture toughness. The work gives a comprehensive report of the background theory and the different applications of the Master Curve methodology. The main results of the work have shown that the cleavage fracture toughness is characterized by a large amount of statistical scatter in the transition region, it is specimen size dependent and it should be treated statistically rather than deterministically. The Master Curve methodology is able to make use of statistical data in a consistent way. Furthermore, the Master Curve methodology provides a more precise prediction of the fracture toughness of embrittled materials in comparison with the ASME K{sub IC} reference curve, which often gives over-conservative results. The suggested procedure in this study, concerning the application of the Master Curve method in fracture assessments of ferritic steels in the transition region and the low shelf regions, is valid for the temperatures range T{sub 0}-50{<=}T{<=}T{sub 0}+50 deg C. If only approximate information is required, the Master Curve may well be extrapolated outside this temperature range. The suggested procedure has also been illustrated for some examples.

The Mathematical Basis of the Inverse Scattering Problem for Cracks from Near-Field Data

Directory of Open Access Journals (Sweden)

Yao Mao

2015-01-01

Full Text Available We consider the acoustic scattering problem from a crack which has Dirichlet boundary condition on one side and impedance boundary condition on the other side. The inverse scattering problem in this paper tries to determine the shape of the crack and the surface impedance coefficient from the near-field measurements of the scattered waves, while the source point is placed on a closed curve. We firstly establish a near-field operator and focus on the operator’s mathematical analysis. Secondly, we obtain a uniqueness theorem for the shape and surface impedance. Finally, by using the operator’s properties and modified linear sampling method, we reconstruct the shape and surface impedance.

Statistical study of clone survival curves after irradiation in one or two stages. Comparison and generalization of different models

International Nuclear Information System (INIS)

Lachet, Bernard.

1975-01-01

A statistical study was carried out on 208 survival curves for chlorella subjected to γ or particle radiations. The computing programmes used were written in Fortran. The different experimental causes contributing to the variance of a survival rate are analyzed and consequently the experiments can be planned. Each curve was fitted to four models by the weighted least squares method applied to non-linear functions. The validity of the fits obtained can be checked by the F test. It was possible to define the confidence and prediction zones around an adjusted curve by weighting of the residual variance, in spite of error on the doses delivered; the confidence limits can them be fixed for a dose estimated from an exact or measured survival. The four models adopted were compared for the precision of their fit (by a non-parametric simultaneous comparison test) and the scattering of their adjusted parameters: Wideroe's model gives a very good fit with the experimental points in return for a scattering of its parameters, which robs them of their presumed meaning. The principal component analysis showed the statistical equivalence of the 1 and 2 hit target models. Division of the irradiation into two doses, the first fixed by the investigator, leads to families of curves for which the equation was established from that of any basic model expressing the dose survival relationship in one-stage irradiation [fr

Implementation of the Master Curve method in ProSACC

Energy Technology Data Exchange (ETDEWEB)

Feilitzen, Carl von; Sattari-Far, Iradj [Inspecta Technology AB, Stockholm (Sweden)

2012-03-15

Cleavage fracture toughness data display normally large amount of statistical scatter in the transition region. The cleavage toughness data in this region is specimen size-dependent, and should be treated statistically rather than deterministically. Master Curve methodology is a procedure for mechanical testing and statistical analysis of fracture toughness of ferritic steels in the transition region. The methodology accounts for temperature and size dependence of fracture toughness. Using the Master Curve methodology for evaluation of the fracture toughness in the transition region releases the overconservatism that has been observed in using the ASME-KIC curve. One main advantage of using the Master Curve methodology is possibility to use small Charpy-size specimens to determine fracture toughness. Detailed description of the Master Curve methodology is given by Sattari-Far and Wallin [2005). ProSACC is a suitable program in using for structural integrity assessments of components containing crack like defects and for defect tolerance analysis. The program gives possibilities to conduct assessments based on deterministic or probabilistic grounds. The method utilized in ProSACC is based on the R6-method developed at Nuclear Electric plc, Milne et al [1988]. The basic assumption in this method is that fracture in a cracked body can be described by two parameters Kr and Lr. The parameter Kr is the ratio between the stress intensity factor and the fracture toughness of the material. The parameter Lr is the ratio between applied load and the plastic limit load of the structure. The ProSACC assessment results are therefore highly dependent on the applied fracture toughness value in the assessment. In this work, the main options of the Master Curve methodology are implemented in the ProSACC program. Different options in evaluating Master Curve fracture toughness from standard fracture toughness testing data or impact testing data are considered. In addition, the

Implementation of the Master Curve method in ProSACC

International Nuclear Information System (INIS)

Feilitzen, Carl von; Sattari-Far, Iradj

2012-03-01

Cleavage fracture toughness data display normally large amount of statistical scatter in the transition region. The cleavage toughness data in this region is specimen size-dependent, and should be treated statistically rather than deterministically. Master Curve methodology is a procedure for mechanical testing and statistical analysis of fracture toughness of ferritic steels in the transition region. The methodology accounts for temperature and size dependence of fracture toughness. Using the Master Curve methodology for evaluation of the fracture toughness in the transition region releases the overconservatism that has been observed in using the ASME-KIC curve. One main advantage of using the Master Curve methodology is possibility to use small Charpy-size specimens to determine fracture toughness. Detailed description of the Master Curve methodology is given by Sattari-Far and Wallin [2005). ProSACC is a suitable program in using for structural integrity assessments of components containing crack like defects and for defect tolerance analysis. The program gives possibilities to conduct assessments based on deterministic or probabilistic grounds. The method utilized in ProSACC is based on the R6-method developed at Nuclear Electric plc, Milne et al [1988]. The basic assumption in this method is that fracture in a cracked body can be described by two parameters Kr and Lr. The parameter Kr is the ratio between the stress intensity factor and the fracture toughness of the material. The parameter Lr is the ratio between applied load and the plastic limit load of the structure. The ProSACC assessment results are therefore highly dependent on the applied fracture toughness value in the assessment. In this work, the main options of the Master Curve methodology are implemented in the ProSACC program. Different options in evaluating Master Curve fracture toughness from standard fracture toughness testing data or impact testing data are considered. In addition, the

High temperature oxidation and crystallization behavior of phosphate glass compositions

International Nuclear Information System (INIS)

Russo, Diego; Rodriguez, Diego; Grumbaum, N.; Gonzalez Oliver, Carlos

2003-01-01

We analyzed the thermal transformation of three iron phosphate glasses having the following nominal compositions: M4 [70% P 2 O 5 , 30% Fe 2 O 3 ], M5 [85% M4, 15% UO 2 ] y M7 [69.7% P 2 O 5 , 28.6% Fe 2 O 3 , 1,7% Al 2 O 3 ]. Thermogravimetric analysis, DTA (differential thermal analysis) and SAXS (Small Angle X-ray Scattering) were performed.It was observed that it is easily possible to produce glasses in these systems having very low crystallinity.We could determine the final stable crystalline phases [Fe 4 (P 2 O 7 ) 3 , Fe(PO 3 ) 3 and Fe 3 (P 2 O 7 ) 2 ].The presence of uranium ions affects not only the redox effects but also the crystallization of the system.SAXS data obtained during the heating in vacuum up to ∼600degC, gave some variation of scattering intensities vs. scattering vector suggesting the development of an extra phase or some kind inhomogeneities that seems to disappear on heating

Practical considerations in the calculation of orientation distribution functions from electron back-scattered diffraction patterns

International Nuclear Information System (INIS)

Bowen, A.W.

1994-01-01

Using model data sets for the Brass orientation, the importance of scatter width, angular accuracy and grain size and volume fraction on the sensitivity of the calculated Orientation Distribution Functions have been determined in order to highlight some of the practical considerations needed in the processing of experimental data from individual grain orientation measurements determined by the Electron Back-Scattered Diffraction technique. It is suggested that the most appropriate scatter width can be calculated from the maximum function height versus scatter width curve in order to accommodate variations in texture sharpness. The sensitivity of the ODF to careful sample preparation, mounting and pattern analysis, in order to keep errors in angular accuracy to 1 or less is demonstrated, as is the imperative need to correct for the size of grains, and their volume fractions. (orig.)

Theoretical Aspects of Phonon Dispersion Curves for Metals

International Nuclear Information System (INIS)

Cochran, W.

1965-01-01

Reasonably complete knowledge of the phonon dispersion curves for at least a dozen metallic elements and intermetallic compounds has now been obtained from neutron inelastic scattering experiments. The results have one feature in common: when analysed in terms of interatomic force constants they reveal the presence of comparatively long-range forces extending over several atomic spacings. The results for lead are particularly interesting; it did not prove possible to fit them by a force-constant model, but the dispersion curves for wave vectors in symmetry directions when analysed in terms of force constants between planes of atoms showed an oscillatory interatomic potential extending over distances of more than 20Å. This review is concerned with recent theoretical work which has a bearing on the calculation of phonon dispersion curves for metals and the explanation of the long range of the interatomic potential. The best hope at present for a general treatment of atomic interaction in metals appears to lie in the ''method of neutral pseudo-atoms'', (a description recently coined by Ziman). This approximate theory is outlined and its relevance to Kohn anomalies in phonon dispersion curves is discussed. Experimental data for sodium is consistent with the theory, and the interatomic potential in sodium varies periodically in a distance π/k F , where fik F is the Fermi momentum, as has already been demonstrated by Koenig in a different way. More exact calculations have been made for sodium by Toya and by Sham. The relationship between the different methods and other work of a more general character such as that of Harrison are discussed. (author) [fr

Small angle X-ray scattering-based elucidation of the self-association mechanism of human insulin analogue lys(B29)(N(e)¿-carboxyheptadecanoyl) des(B30)

DEFF Research Database (Denmark)

Jensen, Malene Hillerup; Wahlund, Per-Olof; Toft, Katrine Nørgaard

2013-01-01

of biophysical and structural methods (field flow fractionation, dynamic and multiangle light scattering, circular dichroism, size exclusion chromatography, and crystallography), we propose a mechanism for the self-association expected to occur upon subcutaneous injection of this insulin analogue. SAXS data...... provide evidence of the in solution structure of the self-associated oligomer, which is a long straight rod composed of "tense" state insulin hexamers (T(6)-hexamers) as the smallest repeating unit. The smallest oligomer building block in the process is a T(6)T(6)-dihexamer. This tense dihexamer is formed...... by the allosteric change of the initial equilibrium between a proposed "relaxed" state R(6)-hexamer and an R(3)T(3)T(3)R(3)-dihexamer. The allosteric change from relaxed to tense is triggered by removal of phenol, mimicking subcutaneous injection. The data hence provide the first unequivocal evidence...

Quantum optics in multiple scattering random media

DEFF Research Database (Denmark)

Lodahl, Peter; Lagendijk, Ad

2005-01-01

Quantum Optics in Multiple Scattering Random Media Peter Lodahl Research Center COM, Technical University of Denmark, Dk-2800 Lyngby, Denmark. Coherent transport of light in a disordered random medium has attracted enormous attention both from a fundamental and application point of view. Coherent......-tions that should be readily attainable experimentally is devised. Figure 1. Inverse total transmission of shot noise (left) and technical noise (right) as a function of the thickness of the ran-dom medium. The experimental data are well explained by theory (curves). [1] J. Tworzydlo and C.W.J. Beenakker, Phys. Rev...

A non-destructive technique for assigning effective atomic number to scientific samples by scattering of 59.54 keV gamma photons

International Nuclear Information System (INIS)

Singh, M.P.; Sharma, Amandeep; Singh, Bhajan; Sandhu, B.S.

2010-01-01

The objective of present experiment, employing a scattering of 59.54 keV gamma photons, is to assign effective atomic number (Z eff ) to scientific samples (rare earths) of known composition. An HPGe semiconductor detector, placed at 90 o to the incident beam, detects gamma photons scattered from the sample under investigation. The experiment is performed on various elements with atomic number satisfying, 6≤Z≤82, for 59.54 keV incident photons. The intensity ratio of Rayleigh to Compton scattered peaks, corrected for photo-peak efficiency of gamma detector and absorption of photons in the sample and air, is plotted as a function of atomic number and constituted a best fit-curve. From this fit-curve, the respective effective atomic numbers to samples of rare earths are determined. The agreement of measured values of Z eff with theoretical calculations is quite satisfactory.

Delivery of siRNA Complexed with Palmitoylated α-Peptide/β-Peptoid Cell-Penetrating Peptidomimetics: Membrane Interaction and Structural Characterization of a Lipid-Based Nanocarrier System

DEFF Research Database (Denmark)

Jing, Xiaona; Foged, Camilla; Martin-Bertelsen, Birte

2016-01-01

. Cryo-transmission electron microscopy (cryo-TEM) revealed multilamellar, onion-like spherical vesicles, and small-angle X-ray scattering (SAXS) analysis confirmed that the majority of the lipids in the nanocarriers were organized in lamellar structures, yet coexisted with a hexagonal phase, which...

Thermal-neutron multiple scattering: critical double scattering

International Nuclear Information System (INIS)

Holm, W.A.

1976-01-01

A quantum mechanical formulation for multiple scattering of thermal-neutrons from macroscopic targets is presented and applied to single and double scattering. Critical nuclear scattering from liquids and critical magnetic scattering from ferromagnets are treated in detail in the quasielastic approximation for target systems slightly above their critical points. Numerical estimates are made of the double scattering contribution to the critical magnetic cross section using relevant parameters from actual experiments performed on various ferromagnets. The effect is to alter the usual Lorentzian line shape dependence on neutron wave vector transfer. Comparison with corresponding deviations in line shape resulting from the use of Fisher's modified form of the Ornstein-Zernike spin correlations within the framework of single scattering theory leads to values for the critical exponent eta of the modified correlations which reproduce the effect of double scattering. In addition, it is shown that by restricting the range of applicability of the multiple scattering theory from the outset to critical scattering, Glauber's high energy approximation can be used to provide a much simpler and more powerful description of multiple scattering effects. When sufficiently close to the critical point, it provides a closed form expression for the differential cross section which includes all orders of scattering and has the same form as the single scattering cross section with a modified exponent for the wave vector transfer

Q resolution calculation of small angle neutron scattering spectrometer and analysis of form factor

International Nuclear Information System (INIS)

Chen Liang; Peng Mei; Wang Yan; Sun Liangwei; Chen Bo

2011-01-01

The calculational methods of Small Angle Neutron Scattering (SANS) spectrometer Q resolution function and its correlative Q standard difference were introduced. The effects of Q standard difference were analysed with the geometry lay out of spectrometer and the spread of neutron wavelength. The one dimension Q resolution Gaussian function were analysed. The form factor curve of ideal solid sphere and two different instrument arrangement parameter was convoluted respectively and the different smearing curve of form factor was obtained. The combination of using the Q resolution function to more accurately analysis SANS data. (authors)

Computation of the optical properties of turbid media from slope and curvature of spatially resolved reflectance curves

International Nuclear Information System (INIS)

Jäger, Marion; Foschum, Florian; Kienle, Alwin

2013-01-01

The optical properties of turbid media were calculated from the curvature at the radial distance ρ O and the slope at the radial distance ρ* of simulated spatially resolved reflectance curves (ρ O (ρ*) denotes a decrease of the spatially resolved reflectance curve of 0.75 (2.4) orders of magnitude relative to the reflectance value at 1.2 mm). We found correlations between the curvature at ρ O and the reduced scattering coefficient as well as the slope at ρ* and the absorption coefficient. For the determination of the optical properties we used these two correlations. The calculation of the reduced scattering coefficient from the curvature at ρ O is practically independent from the absorption coefficient. Knowing the reduced scattering coefficient within a certain accuracy allows the determination of the absorption coefficient from the slope at ρ*. Additionally, we investigated the performance of an artificial neural network for the determination of the optical properties using the above explained correlations. This means we used the derivatives as input data. Our artificial neural network was capable to learn the mapping between the optical properties and the derivatives. In effect, the results for the determined optical properties improved in comparison to the above explained method. Finally, the procedure was compared to an artificial neural network that was trained without using the derivatives. (note)

X-ray heating and the optical light curve of HZ Herculis

International Nuclear Information System (INIS)

Perrenod, S.C.; Shields, G.A.

1975-01-01

We discuss theoretically the optical light curve of HZ Her, the binary companion of the pulsed X-ray source Her X-1. Using model stellar atmospheres, we construct light curves that are in agreement with UBV photometry of HZ Her except for the sharpness of the minimum. Unlike previous authors, we find that heating of the photosphere of HZ Her by the observed X-ray flux is sufficient to explain the amplitude of the light variations in each color, if the X-ray emission persists at HZ Her throughout the 35-day ON-OFF CYCLE. We rule out a corona surrounding HZ Her as the source of the extra light near minimum, and we also rule out a model wherein the extra light is caused by a stellar wind that electron-scatters optical light emitted by the photosphere of the hot side of the star

Probing multi-scale mechanical damage in connective tissues using X-ray diffraction.