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Sample records for voltametry small angle

  1. Small Angle Neutron Scattering

    Energy Technology Data Exchange (ETDEWEB)

    Urban, Volker S [ORNL

    2012-01-01

    Small Angle Neutron Scattering (SANS) probes structural details at the nanometer scale in a non-destructive way. This article gives an introduction to scientists who have no prior small-angle scattering knowledge, but who seek a technique that allows elucidating structural information in challenging situations that thwart approaches by other methods. SANS is applicable to a wide variety of materials including metals and alloys, ceramics, concrete, glasses, polymers, composites and biological materials. Isotope and magnetic interactions provide unique methods for labeling and contrast variation to highlight specific structural features of interest. In situ studies of a material s responses to temperature, pressure, shear, magnetic and electric fields, etc., are feasible as a result of the high penetrating power of neutrons. SANS provides statistical information on significant structural features averaged over the probed sample volume, and one can use SANS to quantify with high precision the structural details that are observed, for example, in electron microscopy. Neutron scattering is non-destructive; there is no need to cut specimens into thin sections, and neutrons penetrate deeply, providing information on the bulk material, free from surface effects. The basic principles of a SANS experiment are fairly simple, but the measurement, analysis and interpretation of small angle scattering data involves theoretical concepts that are unique to the technique and that are not widely known. This article includes a concise description of the basics, as well as practical know-how that is essential for a successful SANS experiment.

  2. Small angle neutron scattering

    Directory of Open Access Journals (Sweden)

    Cousin Fabrice

    2015-01-01

    Full Text Available Small Angle Neutron Scattering (SANS is a technique that enables to probe the 3-D structure of materials on a typical size range lying from ∼ 1 nm up to ∼ a few 100 nm, the obtained information being statistically averaged on a sample whose volume is ∼ 1 cm3. This very rich technique enables to make a full structural characterization of a given object of nanometric dimensions (radius of gyration, shape, volume or mass, fractal dimension, specific area… through the determination of the form factor as well as the determination of the way objects are organized within in a continuous media, and therefore to describe interactions between them, through the determination of the structure factor. The specific properties of neutrons (possibility of tuning the scattering intensity by using the isotopic substitution, sensitivity to magnetism, negligible absorption, low energy of the incident neutrons make it particularly interesting in the fields of soft matter, biophysics, magnetic materials and metallurgy. In particular, the contrast variation methods allow to extract some informations that cannot be obtained by any other experimental techniques. This course is divided in two parts. The first one is devoted to the description of the principle of SANS: basics (formalism, coherent scattering/incoherent scattering, notion of elementary scatterer, form factor analysis (I(q→0, Guinier regime, intermediate regime, Porod regime, polydisperse system, structure factor analysis (2nd Virial coefficient, integral equations, characterization of aggregates, and contrast variation methods (how to create contrast in an homogeneous system, matching in ternary systems, extrapolation to zero concentration, Zero Averaged Contrast. It is illustrated by some representative examples. The second one describes the experimental aspects of SANS to guide user in its future experiments: description of SANS spectrometer, resolution of the spectrometer, optimization of

  3. Small angle scattering and polymers

    Energy Technology Data Exchange (ETDEWEB)

    Cotton, J.P. [Laboratoire Leon Brillouin (LLB) - Centre d`Etudes de Saclay, 91 - Gif-sur-Yvette (France)

    1996-12-31

    The determination of polymer structure is a problem of interest for both statistical physics and industrial applications. The average polymer structure is defined. Then, it is shown why small angle scattering, associated with isotopic substitution, is very well suited to the measurement of the chain conformation. The corresponding example is the old, but pedagogic, measurement of the chain form factor in the polymer melt. The powerful contrast variation method is illustrated by a recent determination of the concentration profile of a polymer interface. (author) 12 figs., 48 refs.

  4. Nucleation of small angle boundaries

    CSIR Research Space (South Africa)

    Nabarro, FRN

    1996-12-01

    Full Text Available The internal stresses induced by the strain gradients in an array of lattice cells delineated by low-angle dislocation boundaries are partially relieved by the creation of new low-angle boundaries. This is shown to be a first-order transition...

  5. 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 ...

  6. The small angle diffractometer SANS at PSI

    Energy Technology Data Exchange (ETDEWEB)

    Wagner, W. [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1996-11-01

    With the start-up of SINQ an instrument for small angle neutron scattering will be operational which compares well with the world`s largest and most powerful facilities of this kind. Following the classical principle of the D11-instrument of ILL, it is equipped with state-of-the-art components as are nowadays available, including options for further upgrading. Great emphasis was laid upon providing a flexible, universal multi-user facility which guarantees a comfortable and reliable operation. In the present paper, the principle layout of the instrument is presented, and the individual components are described in detail. The paper concludes with model application of small angle scattering to a system of dilute CuCo alloys which undergo a phase separation under thermal treatment, forming spherical Co-precipitates dispersed in a Cu-rich matrix. (author) 3 figs., 1 tab., 14 refs.

  7. Small angle electron diffraction and deflection

    OpenAIRE

    T. Koyama; K. Takayanagi; Y. Togawa; S. Mori; K. Harada

    2012-01-01

    Electron optical system is constructed in order to obtain small angle diffraction and Lorentz deflection of electrons at the order of down to 10-6 radian in the reciprocal space. Long-distance camera length up to 3000 m is achieved in a conventional transmission electron microscope with LaB6 thermal emission type. The diffraction pattern at 5 × 10-6 radian is presented in a carbon replica grating with 500 nm lattice spacing while the magnetic deflection pattern at 2 × 10-5 radian is exhibited...

  8. Small angle electron diffraction and deflection

    Directory of Open Access Journals (Sweden)

    T. Koyama

    2012-03-01

    Full Text Available Electron optical system is constructed in order to obtain small angle diffraction and Lorentz deflection of electrons at the order of down to 10-6 radian in the reciprocal space. Long-distance camera length up to 3000 m is achieved in a conventional transmission electron microscope with LaB6 thermal emission type. The diffraction pattern at 5 × 10-6 radian is presented in a carbon replica grating with 500 nm lattice spacing while the magnetic deflection pattern at 2 × 10-5 radian is exhibited in Permalloy elements. A simultaneous recording of electron diffraction and Lorentz deflection is also demonstrated in 180 degree striped magnetic domains of La0.825Sr0.175MnO3.

  9. Neutron elastic scattering at very small angles

    CERN Multimedia

    2002-01-01

    This experiment will measure neutron-proton elastic scattering at very small angles and hence very small four-momentum transfer, |t|. The range of |t| depends on the incident neutron momentum of the events but the geometrical acceptance will cover the angular range 0.025 < $\\Theta_{lab}$ < 1.9 mrad. The higher figure could be extended to 8.4 mrad by changing the geometry of the experiment in a later phase. \\\\ \\\\ The neutron beam will be highly collimated and will be derived from a 400 GeV external proton beam of up to $4 \\times 10^{10}$ protons per pulse in the SPS North Area Hall 1. The hydrogen target will be gaseous, operating at 40 atm. pressure and acts as a multiwire proportional chamber to detect the recoil protons. The forward neutron will be detected and located by interaction in a neutron vertex detector and its energy measured by a conventional steel plate calorimeter. \\\\ \\\\ The experiment will cover the angular region of nucleon-nucleon scattering which is dominated by Coulomb scattering ...

  10. Small-angle neutron scattering studies of sodium butyl benzene ...

    Indian Academy of Sciences (India)

    Na-NBBS), in aqueous solutions is investigated by small-angle neutron scattering (SANS). Nearly ellipsoidal aggregates of Na-NBBS at concentrations well above its minimum hydrotrope concentration were detected by SANS. The hydrotrope ...

  11. Small-angle neutron scattering on polymer gels

    Energy Technology Data Exchange (ETDEWEB)

    Shibayama, Mitsuhiro [Department of Polymer Science and Engineering, Kyoto Institute of Technology, Kyoto (Japan)

    1999-10-01

    Recent development on the small-angle neutron scattering studies on polymer gels has been reviewed with an emphasis of the importance of the static inhomogeneities. The well-known phenomenon of the cross-linking inhomogeneities, i.e., a strong upturn of the scattered intensity at low scattering angles, is interpreted with the static inhomogeneities. It is demonstrated that the gel structures are now well characterized with the novel theories, which take account of the static inhomogeneities. (author)

  12. Gluon transport equations with condensate in the small angle approximation

    Energy Technology Data Exchange (ETDEWEB)

    Blaizot, Jean-Paul [Institut de Physique Théorique (IPhT), CNRS/URA2306, CEA Saclay, F-91191 Gif-sur-Yvette (France); Liao, Jinfeng [Physics Department and Center for Exploration of Energy and Matter, Indiana University, 2401 N Milo B. Sampson Lane, Bloomington, IN 47408 (United States); RIKEN BNL Research Center, Bldg. 510A, Brookhaven National Laboratory, Upton, NY 11973 (United States)

    2016-05-15

    We derive the set of kinetic equations that control the evolution of gluons in the presence of a condensate. We show that the dominant singularities remain logarithmic when the scattering involves particles in the condensate. This allows us to define a consistent small angle approximation.

  13. Small angle neutron scattering study on the aggregation behaviour ...

    Indian Academy of Sciences (India)

    Small angle neutron scattering (SANS) measurements on aqueous solutions of four polyethylene oxide–polypropylene oxide–polyethylene oxide block copolymers (commercially known as Pluronic®)F88, P85, F127 and P123 in the presence of hydrophobic C14Diol (also known as Surfynol® 104) reveal information on ...

  14. Multiple small-angle neutron scattering studies of anisotropic materials

    CERN Document Server

    Allen, A J; Long, G G; Ilavsky, J

    2002-01-01

    Building on previous work that considered spherical scatterers and randomly oriented spheroidal scatterers, we describe a multiple small-angle neutron scattering (MSANS) analysis for nonrandomly oriented spheroids. We illustrate this with studies of the multi-component void morphologies found in plasma-spray thermal barrier coatings. (orig.)

  15. Small angle neutron scattering studies of mixed micelles of sodium ...

    Indian Academy of Sciences (India)

    2015-11-27

    Nov 27, 2015 ... The aqueous solutions of sodium cumene sulphonate (NaCS) and its mixtures with each of cetyl trimethylammonium bromide (CTAB) and sodium dodecyl sulphate (SDS) are characterized by small angle neutron scattering (SANS). NaCS when added to CTAB solution leads to the formation of long ...

  16. Small angle neutron scattering study of mixed micelles of oppositely ...

    Indian Academy of Sciences (India)

    Structures of mixed micelles of oppositely charged surfactants dodecyltrimethylammonium bromide (DTAB) and sodium dodecyl sulphate (SDS) have been studied using small angle neutron scattering. The concentration of one of the components was kept fixed (0.3 M) and that of another varied in the range 0 to 0.1 M. The ...

  17. Small Angle Neutron Scattering instrument at Malaysian TRIGA reactor

    Energy Technology Data Exchange (ETDEWEB)

    Shukri Mohd; Razali Kassim; Zal Uyun Mahmood [Malaysian Inst. for Nuclear Technology Research (MINT), Bangi, Kajang (Malaysia); Shahidan Radiman

    1998-10-01

    The TRIGA MARK II Research reactor at the Malaysian Institute for Nuclear Research (MINT) was commissioned in July 1982. Since then various works have been performed to utilise the neutrons produced from this steady state reactor. One of the project involved the Small Angle Neutron Scattering (SANS). (author)

  18. Small angle neutron scattering studies on the interaction of cationic ...

    Indian Academy of Sciences (India)

    The structure of the protein–surfactant complex of bovine serum albumin (BSA) and cationic surfactants has been studied by small angle neutron scattering. At low concentrations, the CTAB monomers are observed to bind to the protein leading to an increase in its size. On the other hand at high concentrations, surfactant ...

  19. Small-angle neutron scattering from micellar solutions

    Indian Academy of Sciences (India)

    The structure (shape and size) and the interaction of these aggregates, referred to as micelles, depend on the molecular architecture of the surfactant molecule, presence of additives and the solution conditions such as temperature, concentration etc. This paper gives the usefulness of small-angle neutron scattering to the ...

  20. Temperature dependent small-angle neutron scattering of CTABr ...

    Indian Academy of Sciences (India)

    Small-angle neutron scattering studies have been carried out to check the structural integrity of citryltrimethylammonium bromide (CTABr) micelles in a magnetic fluid for different magnetic fluid concentrations at two different temperatures 303 and 333 K. It is found that the CTABr micelles grow with increasing magnetic fluid ...

  1. Linear Relations Among Small-Angle Scattering Intensities

    Energy Technology Data Exchange (ETDEWEB)

    Ciccariello, S. [University of Padua, Padua (Italy)

    2008-01-15

    We give the general conditions to be fulfilled for the small-angle scattering intensities of samples, differing in their scattering densities and volume fractions, to be linearly related us well as the analytical expressions of the coefficients of the linear relations in terms of the above parameters. An application to a natural coal undergoing fluid extraction processes is also discussed.

  2. Spin-Echo Small-Angle Neutron Scattering Development

    NARCIS (Netherlands)

    Uca, O.

    2003-01-01

    Spin-Echo Small-Angle Neutron Scattering (SESANS) instrument is a novel SANS technique which enables one to characterize distances from a few nanometers up to the micron range. The most striking difference between normal SANS and SESANS is that in SESANS one gets information in real space, whereas

  3. Small-angle neutron scattering in materials science - an introduction

    Energy Technology Data Exchange (ETDEWEB)

    Fratzl, P. [Vienna Univ., Inst. fuer Materialphysik, Vienna (Austria)

    1996-12-31

    The basic principles of the application of small-angle neutron scattering to materials research are summarized. The text focusses on the classical methods of data evaluation for isotropic and for anisotropic materials. Some examples of applications to the study of alloys, porous materials, composites and other complex materials are given. (author) 9 figs., 38 refs.

  4. Small-angle neutron scattering studies of nonionic surfactant: Effect ...

    Indian Academy of Sciences (India)

    concentration of sugar. The structure of micelles is almost independent of the different types of sugars used. Keywords. Small-angle neutron scattering; nonionic surfactant; micellar aggregation number. PACS Nos 61.12.Ex; 82.70.Uv. 1. Introduction. Surfactant molecules self assemble into aggregates in aqueous solution to ...

  5. Temperature dependent small-angle neutron scattering of CTABr ...

    Indian Academy of Sciences (India)

    K. It is found that the CTABr micelles grow with increasing magnetic fluid concentration and there is a decrease in the micellar size with increase in temperature. Keywords. Magnetic fluids; micellar solutions; small-angle neutron scattering. .... studies [16] where viscosity increases when the magnetic fluid concentration in the.

  6. Small angle neutron scattering studies on the interaction of cationic ...

    Indian Academy of Sciences (India)

    Abstract. The structure of the protein–surfactant complex of bovine serum albumin. (BSA) and cationic surfactants has been studied by small angle neutron scattering. At low concentrations, the CTAB monomers are observed to bind to the protein leading to an increase in its size. On the other hand at high concentrations, ...

  7. Polarization optimization of spin-echo small angle scattering instruments

    NARCIS (Netherlands)

    Rekveldt, M.T.; Duif, C.P.; Kraan, W.H.; Plomp, J.; Bouwman, W.G.

    2008-01-01

    The polarization optimization in a small angle scattering spin-echo setup is considered, under the depolarization and phase errors that occur in field transition regions by improper adjustment of inclined magnetized foils as n-flippers. Various correction procedures are discussed. In these setups

  8. Small angle neutron scattering study of mixed micelles of oppositely ...

    Indian Academy of Sciences (India)

    is significantly different from that of the addition of DTAB on SDS. The contrast variation. SANS experiments using deuterated surfactant suggests the homogeneous mixing of two components in mixed micellar system. Keywords. Surfactants; mixed micelles; small angle neutron scattering. PACS Nos 61.12.Ex; 82.70.Uv. 1.

  9. Small-angle scattering and quasiclassical approximation beyond leading order

    CERN Document Server

    Krachkov, P A; Milstein, A I

    2015-01-01

    In the present paper we examine the accuracy of the quasiclassical approach on the example of small-angle electron elastic scattering. Using the quasiclassical approach, we derive the differential cross section and the Sherman function for arbitrary localized potential at high energy. These results are exact in the atomic charge number and correspond to the leading and the next-to-leading high-energy small-angle asymptotics for the scattering amplitude. Using the small-angle expansion of the exact amplitude of electron elastic scattering in the Coulomb field, we derive the cross section and the Sherman function with a relative accuracy $\\theta^2$ and $\\theta^1$, respectively ($\\theta$ is the scattering angle). We show that the correction of relative order $\\theta^2$ to the cross section, as well as that of relative order $\\theta^1$ to the Sherman function, originates not only from the contribution of large angular momenta $l\\gg 1$, but also from that of $l\\sim 1$. This means that, in general, it is not possib...

  10. Polarization optimization of spin-echo small angle scattering instruments.

    Science.gov (United States)

    Rekveldt, M Theo; Duif, Chris P; Kraan, Wicher H; Plomp, Jeroen; Bouwman, Wim G

    2008-01-01

    The polarization optimization in a small angle scattering spin-echo setup is considered, under the depolarization and phase errors that occur in field transition regions by improper adjustment of inclined magnetized foils as pi-flippers. Various correction procedures are discussed. In these setups with precession fields perpendicular to the beam directions, corrections can be reduced strongly by the use of pi-flippers, and for the remaining errors, correction coils can be constructed.

  11. 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

  12. The Small Angle Tile Calorimeter project in DELPHI

    Science.gov (United States)

    Alvsvaag, S. J.; Maeland, O. A.; Klovning, A.; Benvenuti, A. C.; Giordano, V.; Guerzoni, M.; Navarria, F. L.; Verardi, M. G.; Camporesi, T.; Vallazza, E.; Bozzo, M.; Cereseto, R.; Barreira, G.; Espirito Santo, M. C.; Maio, A.; Onofre, A.; Peralta, L.; Pimenta, M.; Tome, B.; Carling, H.; Falk, E.; Hedberg, V.; Jarlskog, G.; Kronkvist, I.; Bonesini, M.; Chignoli, F.; Ferrari, P.; Gumenyuk, S.; Leoni, R.; Mazza, R.; Negri, P.; Paganoni, M.; Petrovykh, L.; Terranova, F.; Dharmasiri, D. R.; Nossum, B.; Read, A. L.; Skaali, B.; Castellani, L.; Pegoraro, M.; Fenyuk, A.; Gouz, Yu.; Ivaniouchenkov, Yu.; Karyukhin, A.; Obraztsov, V.; Vlassov, E.; Zaitsev, A.; Bigi, M.; Cassio, V.; Gamba, D.; Migliore, E.; Romero, A.; Simonetti, L.; Torassa, E.; Trapani, P. P.; Bari, M.; Della Ricca, G.; Lanceri, L.; Poropat, P.; Prest, M.

    1995-11-01

    The new Small Angle TIIe Calorimeter (STIC) covers the forward regions in DELPHI. The main motivation for its construction was to achieve a systematic error of 0.1% on the luminosity determination. This detector consists of a "shashlik" type calorimeter, equipped with two planes of silicon pad detectors placed respectively after 4 and 7.4 radiation lengths. A veto counter, composed of two scintillator planes, covers the front of the calorimeter to allow ϱ - γ separation and to provide a neutral energy trigger. The physics motivations for this project, results from extensive testbeam measurements and the performance during the 1994 LEP run are reported here.

  13. The small angle neutron scattering study on the segmented polyurethane

    Energy Technology Data Exchange (ETDEWEB)

    Sudirman; Gunawan; Prasetyo, S.M.; Karo Karo, A.; Lahagu, I.M.; Darwinto, Tri [Materials Science Research Center, National Nuclear Energy Agency, Serpong, Tangerang (Indonesia)

    1999-10-01

    The distance between hard segment (HS) and soft segment (SS) of segmented polyurethane have been determined using the Small Angle Neutron Scattering (SANS) technique. The segmented Polyurethanes (SPU) are linear multiblock copolymers, which include elastomer thermoplastic. SPU consist of hard segment and soft segment, each has tendency to make a group with similar type to form a domain. The soft segments used were polypropylene glycol (PPG) and 4,4 diphenylmethane diisocyanate (MDI), while l,4 butanediol (BD) was used as hard segment. The characteristic of SPU depends on its phase structure which is affected by several factors, such as type of chemical formula and the composition of the HS and SS, solvent as well as the synthesizing process. The samples used in this study were SPU56 and SPU68. Based on the appearance of SANS profile, it was obtained that domain distances are 12.32 nm for the SPU56 and 19 nm for the SPU68. (author)

  14. Small-angle neutron scattering study on irradiated kappa carrageenan

    Energy Technology Data Exchange (ETDEWEB)

    Abad, Lucille [Neutron Science Laboratory, Institute for Solid State Physics, University of Tokyo, 106-1 Shirakata, Tokai, Ibaraki 319-1106 (Japan) and Philippine Nuclear Research Institute, Commonwealth Ave., Diliman, Quezon City (Philippines) and Advanced Science Research Center, Japan Atomic Energy Research Institute, 2-4 Shirane Shirakata, Tokai, Ibaraki 319-1195 (Japan)]. E-mail: lvabad@pnri.dost.gov.ph; Okabe, Satoshi [Neutron Science Laboratory, Institute for Solid State Physics, University of Tokyo, 106-1 Shirakata, Tokai, Ibaraki 319-1106 (Japan); Koizumi, Satoshi [Advanced Science Research Center, Japan Atomic Energy Research Institute, 2-4 Shirane Shirakata, Tokai, Ibaraki 319-1195 (Japan); Shibayama, Mitsuhiro [Neutron Science Laboratory, Institute for Solid State Physics, University of Tokyo, 106-1 Shirakata, Tokai, Ibaraki 319-1106 (Japan)]. E-mail: sibayama@issp.u-tokyo.ac.jp

    2006-05-31

    The structure of gamma-ray-irradiated {kappa}-carrageenan in aqueous solutions was investigated in terms of small-angle neutron scattering. The scattered intensity, I(q), of non-irradiated {kappa}-carrageenan solutions (5 wt%) was well described with an Ornstein-Zernike (OZ)-type function with the correlation length of 85 A, indicating that the {kappa}-carrageenan solution behaves just as a polymer solution in the semi-dilute regime. By increasing the irradiation dose (100 kGy), I(q) changed to a power-law function with the scattering exponent of -1.84. Further increase in dose results in a recovery of OZ-type function. This indicates that a progressive cleavage of {kappa}-carrageenan chains takes place randomly, leading to a self-similar structure at 100 kGy. This is followed by further segmentation of {kappa}-carrageenan chains.

  15. A small angle neutron scattering study of thermoplastic elastomer

    Energy Technology Data Exchange (ETDEWEB)

    Sutiarso; Edy Giri, R. Putra; Andon, Insani; Sudirman; Sudaryanto [Materials Science Research Centre, National Atomic Energy Agency, Jakarta (Indonesia)

    1998-10-01

    A bilateral scientific cooperation, in the small angle neutron scattering has been agreed upon between CIAE, China and BATAN, Indonesia as well as MINT Malaysia. As stated in the agreed proposal that the objective of this cooperation, in the initial stage (stage-1), was to have a regional intercomparison measurements of SANS instruments in order to determine their characteristic/performance. Therefore, this report is supposed to describe the progress in the SANS instrument development of each country involved during the period of 1996/97 and some activities related to the SANS instrument. Since, up to now, we have not yet received any progresses reported from either China or Malaysia, this report will describe the progress of SANS`s activities in BATAN only. (author)

  16. Small-angle scattering study of Aspergillus awamori glycoprotein glucoamylase

    Energy Technology Data Exchange (ETDEWEB)

    Schmidt, A. E., E-mail: schmidt@omrb.pnpi.spb.ru; Shvetsov, A. V. [National Research Center “Kurchatov Institute”, Konstantinov Petersburg Nuclear Physics Institute (Russian Federation); Kuklin, A. I. [Joint Institute for Nuclear Research (Russian Federation); Lebedev, D. V.; Surzhik, M. A.; Sergeev, V. R.; Isaev-Ivanov, V. V. [National Research Center “Kurchatov Institute”, Konstantinov Petersburg Nuclear Physics Institute (Russian Federation)

    2016-01-15

    Glucoamylase from fungus Aspergillus awamori is glycoside hydrolase that catalyzes the hydrolysis of α-1,4- and α-1,6-glucosidic bonds in glucose polymers and oligomers. This glycoprotein consists of a catalytic domain and a starch-binding domain connected by an O-glycosylated polypeptide chain. The conformation of the linker, the relative arrangement of the domains, and the structure of the full-length enzyme are unknown. The structure of the recombinant glucoamylase GA1 was studied by molecular modelling and small-angle neutron scattering (SANS) methods. The experimental SANS data provide evidence that glucoamylase exists as a monomer in solution and contains a glycoside component, which makes a substantial contribution to the scattering. The model of full-length glucoamylase, which was calculated without taking into account the effect of glycosylation, is consistent with the experimental data and has a radius of gyration of 33.4 ± 0.6 Å.

  17. Leptogenesis and the Small-Angle MSW Solution

    Science.gov (United States)

    Goldberg, Haim

    The lepton asymmetry created in the out-of-equilibrium decay of a heavy Majorana neutrino can generate the cosmological baryon asymmetry YB when processed through fast anomalous electroweak reactions. In this work I examine this process under the following assumptions: (1) maximal νμ-ντ mixing (2) hierarchical mass spectrum m3 ≃ 5 × 10-2 roman>eVroman> ≫ m2 ≫ m1 (3) small-angle MSW solution to the solar neutrino deficit. For a variety of textures for the Dirac neutrino yukawa matrix, these constraints imply a lower bound of 10l0 - 1012 roman>GeVroman> for the lightest right-handed neutrino. The results are insensitive to the masses of the heavier right-handed neutrinos.

  18. Small angle neutron scattering study of lysozyme solutions

    Science.gov (United States)

    Boué, F.; Lefaucheux, F.; Robert, M. C.; Rosenman, I.

    1993-10-01

    In order to investigate how macromolecular aggregation proceeds for obtaining nucleation and crystal growth, a series of hen egg white (HEW) lysozyme solutions representative of a large supersaturation range have been investigated by small angle neutron scattering (SANS). In all these solutions, the signal well corresponds to species of radii of gyration Rg below 50 Å. Moreover, the effective values Rg are compatible with a rather monodisperse distribution of species the size of which increases when the supersaturation increases; for example, saturated solutions correspond to dimer populations. The largest size which has been identified corresponds to octomers which seems a limit beyond which nucleation and growth occur. The growth units are larger than dimers and probably correspond to tetramers or octomers. SANS allows one to study kinetic aspects. We observe that when a given supersaturation is quickly established, the radius of gyration increases with time. In the light of these results, it appears that SANS affords a powerful tool to study aggregation phenomena occurring in the metastable zone.

  19. Probing surface and interface morphology with Grazing Incidence Small Angle X-Ray Scattering

    National Research Council Canada - National Science Library

    Renaud, Gilles; Lazzari, Rémi; Leroy, Frédéric

    2009-01-01

    .... their shapes, their sizes and their spatial organization. This calls for dedicated morphological characterization tools, among which is the Grazing Incidence Small Angle X-Ray Scattering (GISAXS...

  20. Magnetic nanoparticles studied by small angle X-ray scattering

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, Cristiano Luis Pinto [Universidade de Sao Paulo (IF/USP), SP (Brazil). Inst. de Fisica. Grupo de Fluidos Complexos; Antonel, Soledad; Negri, Martin [Universidad de Buenos Aires (UBA) (Argentina). Facultad de Ciencias Exactas y Naturales. Dept. de Quimica Inorganica, Analitica y Quimica Fisica

    2011-07-01

    nanoparticles are very interesting because they exhibit magnetic (ferromagnetic) and electrical properties in the same material. Then, the nickel nanoparticles could be used for the development of electroelastic materials. In this case, the electrical conductivity of the material can be strongly dependent on the applied magnetic field, for example the case of nickel metal nanoparticles dispersed in a polymer, resulting in an anisotropic material with combined piezomagnetic and piezoelectric properties. In order to investigate the structural characteristics of cobalt-iron oxides and nickel nanoparticles, powder samples of those magnetic materials were studied by Small-Angle X-Ray Scattering. As will be shown, from the analysis and modeling of the scattering data, structural information could be obtained, enabling a detailed description of the structural properties of the studied samples which could be directly correlated to the magnetic properties. (author)

  1. Monte Carlo calculation of large and small-angle electron scattering in air

    Science.gov (United States)

    Cohen, B. I.; Higginson, D. P.; Eng, C. D.; Farmer, W. A.; Friedman, A.; Grote, D. P.; Larson, D. J.

    2017-11-01

    A Monte Carlo method for angle scattering of electrons in air that accommodates the small-angle multiple scattering and larger-angle single scattering limits is introduced. The algorithm is designed for use in a particle-in-cell simulation of electron transport and electromagnetic wave effects in air. The method is illustrated in example calculations.

  2. Small Signal Analysis of Load Angle Governing and Excitation ...

    African Journals Online (AJOL)

    The scheme is simple and can be manipulated on a PC if adequate computational data is provided. Simulation results obtained using MATLAB ® were revealed by angle-time plots. These results are very similar to results obtained by frequency response analysis. Results of other related schemes modeled with laboratory ...

  3. small signal analysis of load angle governing and excitation control

    African Journals Online (AJOL)

    Dr Obe

    ABSTRACT. A method of obtaining direct pictorial information on the behaviour of synchronous machines under different conditions of control using a single variable related to its load angle is presented. The technique employs a simple control scheme to the linearized model of synchronous machine equations.

  4. TOF-SEMSANS—Time-of-flight spin-echo modulated small-angle neutron scattering

    NARCIS (Netherlands)

    Strobl, M.; Tremsin, A.S.; Hilger, A.; Wieder, F.; Kardjilov, N.; Manke, I.; Bouwman, W.G.; Plomp, J.

    2012-01-01

    We report on measurements of spatial beam modulation of a polarized neutron beam induced by triangular precession regions in time-of-flight mode and the application of this novel technique spin-echo modulated small-angle neutron scattering (SEMSANS) to small-angle neutron scattering in the very

  5. Wavelength-independent constant period spin-echo modulated small angle neutron scattering

    NARCIS (Netherlands)

    Sales, Morten; Plomp, J.; Habicht, Klaus; Tremsin, Anton; Bouwman, W.G.; Strobl, Markus

    2016-01-01

    Spin-Echo Modulated Small Angle Neutron Scattering (SEMSANS) in Time-of-Flight (ToF) mode has been shown to be a promising technique for measuring (very) small angle neutron scattering (SANS) signals and performing quantitative Dark-Field Imaging (DFI), i.e., SANS with 2D spatial resolution.

  6. Small-angle scattering from GP zones in Al–Cu alloy

    Indian Academy of Sciences (India)

    Administrator

    After solutionizing and artificial aging, the aging curve was plotted and small- angle scattering experiments were carried on the powdered samples as a function of time during artificial aging. Small-angle scattering data were analysed, and evidence has been .... zone can be a direct consequence of uphill diffusion, i.e..

  7. Measurement of the small angle scattering of polarized neutrons

    Energy Technology Data Exchange (ETDEWEB)

    Giordano, V.; Manduchi, C.; Russo-Manduchi, M.T.; Segato, G.F. (Padua Univ. (Italy). Ist. di Fisica; Istituto Nazionale di Fisica Nucleare, Padua (Italy))

    1980-06-01

    Described herein is an apparatus designed merely for the purpose of extending previous measurements of the differential cross section and polarization of fast neutrons to scattering angles lower than 1/sup 0/. The principles and properties of the device are developed and discussed in detail. The quality of the performance is illustrated by measuring absolute cross sections of 2.50 MeV neutrons scattered by Bi.

  8. New Type Small-angle Sensor Based on the TIR and SPR Theories in Heterodyne Interferomery

    Directory of Open Access Journals (Sweden)

    Shinn-Fwu Wang

    2009-06-01

    Full Text Available In this paper, a new type small-angle sensor based on the total internal reflection (TIR and surface plasmon resonance (SPR theories in heterodyne interferomery is proposed. With the small-displacement sensor, a small rotation angle can be obtained only by measuring the variation in phase difference between s- and p-polarization states. The best theoretical sensitivity of the small-angle sensor is 2x10-4 degree/degree. And its resolution can reach 1x10-7 radian. The sensor has some merits, e.g., a simple optical setup, high resolution, high sensitivity, rapid measurement.

  9. small signal analysis of load angle governing and excitation control

    African Journals Online (AJOL)

    Dr Obe

    Appendix: Derivation of the small- oscillation equations for a synchronous generator: Park's d-q transformation. The small oscillation theory is bade on. Park's [15] equations for an ideal synchronous machine [16], with no amortissuer windings, connected to an infinite system via a transmission line. The significant advantage ...

  10. Page 1 Small angle neutron scattering from helium bubbles in ...

    Indian Academy of Sciences (India)

    During the SANS data analysis the SDF was not choosen with an a-priori shape, but it was ... small bubbles obtained by the experimental SANS data with those obtained from the simulation code is shown in ... within the usual range of uncertainty, it was found to be in good agreement with the values found in the literature.

  11. Small-Angle X-ray Scattering Screening Complements Conventional Biophysical Analysis

    DEFF Research Database (Denmark)

    Tian, Xinsheng; Langkilde, Annette Eva; Thorolfsson, Matthias

    2014-01-01

    introduce small-angle X-ray scattering (SAXS) to characterize antibody solution behavior, which strongly complements conventional biophysical analysis. First, we apply a variety of conventional biophysical techniques for the evaluation of structural, conformational, and colloidal stability and report...

  12. Reflective Type Small-Angle Sensor Based on Multiple Total Internal Reflections in Heterodyne Interferometry

    Directory of Open Access Journals (Sweden)

    Shinn-Fwu Wang

    2008-12-01

    Full Text Available A reflective type small-angle sensor based on the multiple total internal reflections (MTIRs in heterodyne interferometry is proposed. In the paper, we try to measure the phase difference variation between s- and p-polarizations due to MTIRs. The phase difference variation depends on the incident angle. Therefore, only evaluating the phase difference variation can perform small-angle measurement. The resolution of the method can reach 5.5E-7 radian. The method has some merits, e.g., a simple optical setup, easy operation, high measurement accuracy, high resolution, rapid measurement, and high stability etc. and its feasibility is demonstrated.

  13. Small-angle Sensor Based on the SPR Technology and Heterodyne Interferomery

    Directory of Open Access Journals (Sweden)

    Shinn-Fwu Wang

    2008-05-01

    Full Text Available A small-angle sensor based on the surface plasmon resonance (SPR technology and heterodyne interferometry is proposed. In the paper, we try to measure the phase difference variation between s and p polarizations due to attenuated total reflection (ATR. The phase difference variation depends on the incident angle. Therefore, only evaluating the phase difference variation can perform small-angle measurement. The resolution of the method can reach 2.4 x 10-7 radian. The method has some merits, e.g., a simple optical setup, easy operation, high measurement accuracy, high resolution, rapid measurement, and high stability etc. And its feasibility is demonstrated.

  14. Improved inverted bubble method for measuring small contact angles at crystal-solution-vapor interfaces.

    Science.gov (United States)

    Corti, Thierry; Krieger, Ulrich K

    2007-08-10

    We propose and evaluate an improvement of the inverted bubble method, originally proposed by McLachlan and Cox [Rev. Sci. Instrum. 46, 80 (1975)], a technique for measuring small contact angles at crystal-solution-vapor interfaces on a gas bubble under a solid immersed in a test solution. A simple experimental setup is used to evaluate the proposed method. We conclude that the method is suitable for measuring small contact angles with a minimum detectable angle of about 3 degrees . Improvements in instrument design are proposed to lower the detection limit to 0.5 degrees or below.

  15. ANALISIS LOGAM Cd (II DENGAN METODE VOLTAMETRI PELUCUTAN ANODIK MENGGUNAKAN ELEKTRODA PASTA KARBON TERMODIFIKASI ZEOLIT ALAM

    Directory of Open Access Journals (Sweden)

    Irdhawati Irdhawati

    2017-03-01

    Full Text Available Pada penelitian ini telah dipelajari material zeolit alam teraktivasi asam sulfat 0,1 M yang digunakan sebagai modifier dalam elektroda kerja pasta karbon (EPK. Kinerja EPK termodifikasi zeolit alam teraktivasi asam (EPKZA dibandingkan dengan EPK tanpa modifier dan penerapannya dalam penentuan kadar logam Cd(II dalam sampel sayur dengan metode voltametri pelucutan anodik. Parameter optimasi yang diuji meliputi waktu deposisi dan laju pindai pada EPK dan EPKZA, serta komposisi zeolit dalam EPKZA. Komposisi elektroda kerja terbaik pada kondisi optimum pengukuran digunakan untuk menentukan rentang konsentrasi linier, limit deteksi, ketelitian, dan ketepatan penentuan logam Cd(II. Hasil yang diperoleh yaitu waktu deposisi 630 detikdan laju pindai 10 mV/s menggunakan EPK, dan komposisi modifier terbaik sebesar 5% dalam EPKZA, dengan waktu deposisi  540 detik dan laju pindai 20 mV/s. Rentang konsentrasi pengukuran EPKZA lebih luas yaitu dari 50-2000 ppb, sedangkan EPK tanpa modifier hanya memiliki rentang konsentrasi dari 100-1000 ppb. EPKZA dapat mengukur logam dengan konsentrasi yang lebih rendah dari EPK tanpa modifier, dengan batas deteksi pengukuran EPKZA adalah 58,41 ppb, sedangkan batas deteksi pengukuran EPK tanpa modifier sebesar 94,38 ppb. Keberulangan pengukuran larutan standar logamCd(II dengan EPKZA menghasilkan nilai HorRat yang lebih kecil dari dua, serta nilai persen perolehan kembali sebesar 99,28±3,12 %, sehingga metode ini memiliki keseksamaan dan akurasi yang sangat baik.   In this research the natural zeolite material activated by 0.1 M sulfuric acid was used as a modifier for carbon paste electrode (CPE. The performance of CPE modified by acid activated natural zeolite (CPEZ was compared with CPE without modifier one and applied in the determination of Cd(II concentration in vegetable samples using anodic stripping voltammetry method. The observed parameters includes deposition time and scan rate at CPE and CPEZ, and

  16. A Microbeam Small-Angle X-ray Scattering Study on Enamel Crystallites in Subsurface Lesion

    Energy Technology Data Exchange (ETDEWEB)

    Yagi, N; Ohta, N; Matsuo, T [Japan Synchrotron Radiation Research Institute, 1-1-1 Kouto, Sayo, Hyogo 679-5198 (Japan); Tanaka, T; Terada, Y; Kamasaka, H; Kometani, T, E-mail: yagi@spring8.or.j [Ezaki Glico Co. Ltd., 4-6-5 Utajima, Nishiyodogawa-ku, Osaka 555-8502 (Japan)

    2010-10-01

    The early caries lesion in bovine tooth enamel was studied by two different X-ray diffraction systems at the SPring-8 third generation synchrotron radiation facility. Both allowed us simultaneous measurement of the small and large angle regions. The beam size was 6{mu}m at BL40XU and 50{mu}m at BL45XU. The small-angle scattering from voids in the hydroxyapatite crystallites and the wide-angle diffraction from the hydroxyapatite crystals were observed simultaneously. At BL40XU an X-ray image intensifier was used for the small-angle and a CMOS flatpanel detector for the large-angle region. At BL45XU, a large-area CCD detector was used to cover both regions. A linear microbeam scan at BL40XU showed a detailed distribution of voids and crystals and made it possible to examine the structural details in the lesion. The two-dimensional scan at BL45XU showed distribution of voids and crystals in a wider region in the enamel. The simultaneous small- and wide-angle measurement with a microbeam is a powerful tool to elucidate the mechanisms of demineralization and remineralization in the early caries lesion.

  17. Modelling small-angle scattering data from complex protein-lipid systems

    DEFF Research Database (Denmark)

    Kynde, Søren Andreas Røssell

    as carriers of membrane proteins. Together they form monodisperse soluble aggregates of about 10 nm in size. Chapter 2 introduces the method of small-angle scattering. Small-angle X-ray and neutron scattering are well suited for studying particles in solution on length scales from 1 to 100 nm. This makes...... the techniques very well suited for the study of the nanodisc system. Chapter 3 explains two different modelling approaches that can be used in the analysis of small-angle scattering data from lipid-protein complexes. These are the continuous approach where the system of interest is modelled as a few regular...... geometric objects and the discrete approach were models are build from a large number of points. It is the basic hypothesis of this thesis, that analysis of smallangle scattering data can be approached in a way that combines the continuous and the discrete modelling methods, and that such an approach can...

  18. Data Analysis Of Small Angle X-Ray Solution Scattering And Its ...

    African Journals Online (AJOL)

    Small Angle X-ray Scattering analysis was used for the study of the protein, Human Tumour Necrosis Factor (TNF) homogeneously dispersed in solution. The experiment consisted in sending a well collimated beam of synchrotron radiation of wavelength, λ through the sample and measuring the variation of the intensity as a ...

  19. Small-angle neutron scattering study of a dense microemulsion system formed with an ionic liquid

    Energy Technology Data Exchange (ETDEWEB)

    Kang, T. [Biology and Soft Matter Division; Oak Ridge National Laboratory; Oak Ridge; USA; Qian, S. [Biology and Soft Matter Division; Oak Ridge National Laboratory; Oak Ridge; USA; Smith, G. S. [Biology and Soft Matter Division; Oak Ridge National Laboratory; Oak Ridge; USA; Do, C. [Biology and Soft Matter Division; Oak Ridge National Laboratory; Oak Ridge; USA; Heller, W. T. [Biology and Soft Matter Division; Oak Ridge National Laboratory; Oak Ridge; USA

    2017-01-01

    The structure of the microemulsion formed with an Ionic Liquid (IL) in specific systematic composition series has been investigated by small-angle neutron scattering to understand how the IL can be used to tune the structure and properties of microemulsions.

  20. A small-angle neutron scattering study of cholic acid-based organogel systems

    NARCIS (Netherlands)

    Willemen, H.M.; Marcelis, A.T.M.; Sudhölter, E.J.R.; Bouwman, W.G.; Deme, B.; Terech, P.

    2004-01-01

    Small-angle neutron scattering measurements were performed on some cholic acid-based gel systems in order to gain detailed information about the network structure. The presence of thin fibers with a radius of about 10-20 Å was found for various gelators. Two types of interaction between different

  1. On the Study of the Transfer Ionization Reactions at Super Small Scattering Angles

    CERN Document Server

    Popov, Yu V; Vinitsky, S I; Ancarani, L U; Dal Cappello, C; Vinitsky, P S

    2002-01-01

    The hypothesis that the reaction p + He\\to H + He^{++} + e at super small scattering angles of hydrogen can be used for purposes of the angular spectroscopy of electron-electron correlations in the target is considered. It is shown that this hypothesis is insolvent.

  2. A small angle neutron scattering study on the mixtures of pluronic ...

    Indian Academy of Sciences (India)

    Abstract. Small angle neutron scattering (SANS) experiments have been carried out on the micellar solutions containing mixtures of a hydrophobic triblock copoly- mer (L121, EO5PO68EO5) and a hydrophobic anionic surfactant (AOT, sodium bis(2- ethylhexyl)sulphosuccinate) in water with varying ratio (R) of AOT to L121 ...

  3. Structure of Co–Zn ferrite ferrofluid: A small angle neutron scattering ...

    Indian Academy of Sciences (India)

    A hydrothermal synthesis route is used to synthesize nanomagnetic particles of Co0.3Zn0.7Fe2O4 ferrite ferrofluids with particle diameter ranging from 5.5–9 nm. XRD analysis shows the formation of a single phase spinel structure. EDX results confirm the stoichiometric composition of the cations. Small angle neutron ...

  4. Small angle X-ray scattering study of calreticulin reveals conformational plasticity

    DEFF Research Database (Denmark)

    Toft, Katrine Nørgaard; Larsen, Nanna; Jørgensen, Flemming Steen

    2008-01-01

    Calreticulin plays a central role in vital cell processes such as protein folding, Ca(2+) homeostasis and immunogenicity. Even so, only limited three-dimensional structural information is presently available. We present a series of Small-Angle X-ray Scattering data on human placenta calreticulin...

  5. Small-angle neutron scattering study of aggregate structures of multi ...

    Indian Academy of Sciences (India)

    The aggregate structures of a set of novel single-chain surfactants bearing one, two and three pyridinium headgroups have been studied using small-angle neutron scattering (SANS). It is found that the nature of aggregate structures of these cationic surfactants depend on the number of headgroups present in the ...

  6. Real-time remedial action against aperiodic small signal rotor angle instability

    DEFF Research Database (Denmark)

    Weckesser, Johannes Tilman Gabriel; Jóhannsson, Hjörtur; Østergaard, Jacob

    2016-01-01

    This paper presents a method that in real-time determines remedial actions, which restore stable operation with respect to aperiodic small signal rotor angle stability (ASSRAS) when insecure or unstable operation has been detected. An ASSRAS assessment method is used to monitor the stability...

  7. Small-angle neutron and dynamic light scattering study of gelatin ...

    Indian Academy of Sciences (India)

    The state of intermolecular aggregates and that of folded gelatin molecules could be characterized by dynamic laser light and small-angle neutron scattering experiments, which implied spontaneous segregation of particle sizes preceding coacervation, which is a liquid-liquid phase transition phenomenon. Dynamic light ...

  8. Reversible membrane reorganizations during photosynthesis in vivo: revealed by small-angle neutron scattering

    DEFF Research Database (Denmark)

    Nagy, Gergely; Posselt, Dorthe; Kovacs, Laszlo

    2011-01-01

    In the present study, we determined characteristic repeat distances of the photosynthetic membranes in living cyanobacterial and eukaryotic algal cells, and in intact thylakoid membranes isolated from higher plants with time-resolved small-angle neutron scattering. This non-invasive technique rev...

  9. Application of small-angle neutron scattering (SANS) to the study of coal porosity

    Energy Technology Data Exchange (ETDEWEB)

    Tricker, M.J.; Grint, A.; Audley, G.J.; Church, S.M. (British Petroleum Co. Ltd., Sunbury-on-Thames); Rainey, V.S.; Wright, C.J. (UKAEA Atomic Energy Research Establishment, Harwell)

    1983-09-01

    Pore size distribution functions of coals of different rank obtained from small-angle neutron scattering data are quantitatively consistent with data obtained from adsorption measurements. The agreement will provide a firm foundation for using SANS to probe coal porosity under conditions where conventional gas adsorption techniques are inappropriate.

  10. Application of small-angle neutron scattering (SANS) to the study of coal porosity

    Energy Technology Data Exchange (ETDEWEB)

    Tricker, M.J.; Grint, A.; Audley, G.J.; Church, S.M.; Rainey, V.S.; Wright, C.J.

    1983-09-01

    Pore size distribution functions of coals of different rank obtained from small-angle neutron scattering data are quantitatively consistent with data obtained from adsorption measurements. The agreement will provide a firm foundation for using SANS to probe coal porosity under conditions where conventional gas adsorption techniques are inappropriate. (14 refs.)

  11. Resolution effects and analysis of small-angle neutron scattering data

    DEFF Research Database (Denmark)

    Pedersen, J.S.

    1993-01-01

    A discussion of the instrumental smearing effects for small-angle neutron scattering (SANS) data sets is given. It is shown that these effects can be described by a resolution function, which describes the distribution of scattering vectors probed for the nominal values of the scattering vector. ...

  12. Analysis of small-angle scattering data from micelles and microemulsions

    DEFF Research Database (Denmark)

    Pedersen, J.S.

    1999-01-01

    The free-form methods for analyzing small-angle scattering data have, during the last years, found more widespread use for micelles and microemulsions. Recent developments have made them applicable also to systems with size polydispersity and particle correlations, however, model fitting still co...... constitutes a very important and partly complementary analysis tool. (C) 1999 Elsevier Science Ltd. All rights reserved....

  13. 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.)

  14. Invisible detergents for structure determination of membrane proteins by small-angle neutron scattering

    DEFF Research Database (Denmark)

    Midtgaard, Søren Roi; Darwish, Tamim A.; Pedersen, Martin Cramer

    2018-01-01

    A novel and generally applicable method for determining structures of membrane proteins in solution via small-angle neutron scattering (SANS) is presented. Common detergents for solubilizing membrane proteins were synthesized in isotope-substituted versions for utilizing the intrinsic neutron sca...

  15. Ultra Small-angle X-ray Scattering Study of Flocculation in Silica-filled Rubber

    NARCIS (Netherlands)

    Mihara, S.; Datta, Rabin; Dierkes, Wilma K.; Noordermeer, Jacobus W.M.; Amino, N.; Ishikawa, Y.; Nishitsuji, S.; Takenaka, M.

    2014-01-01

    The flocculation of silica during vulcanization is monitored using the ultra small-angle X-ray scattering technique for two different types of silica: a highly dispersible silica (HD) and a conventional silica (CV), mixed into a blend of S-SBR and BR rubbers. The cutoff length of the silica

  16. V4: The Small Angle Scattering Instrument (SANS at BER II

    Directory of Open Access Journals (Sweden)

    Uwe Keiderling

    2016-11-01

    Full Text Available V4 is a small-angle neutron scatting instrument with an accessible range of scattering vector 0.01 nm-1 < Q < 8.5 nm-1. Outstanding features of the instrument are the polarized neutron option and the list mode data acquisition, allowing for time-resolved measurements with µs time resolution.

  17. Small angles X-ray diffraction and Mössbauer characterization of ...

    Indian Academy of Sciences (India)

    Abstract. The effect of thermal annealing on the structure and magnetic properties of crystalline Tb/Fe multilayers has been studied using conversion electron Mössbauer spectrometry and small-angle X-ray diffraction. The growth of Tb–Fe amorphous alloy from the interface is observed with increasing annealing ...

  18. Small angle neutron scattering study of U(VI) third phase formation ...

    Indian Academy of Sciences (India)

    It was observed that third phase formation takes place due to the formation of. UO2(NO3)2.DHDECMP reverse micelles in the dodecane phase. SANS data obtained were interpreted with particle interaction model using Baxter sticky spheres model. Keywords. Small angle neutron scattering; U(VI); third phase; DHDECMP.

  19. 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.

  20. Imaging diagnosis of various small lesions in the cerebellopontine angle by Suboccipital air CT cisternography

    Energy Technology Data Exchange (ETDEWEB)

    Tsukahara, Kaoru (Toho Univ., Tokyo (Japan). School of Medicine)

    1989-11-01

    A modified air CT cisternography technique, characterized by suboccipital air infusion was carried out in a total of 180 patients over the past 5 years. The patients were divided into two groups according to their suspected lesions. The first group consisted of 151 patients who were diagnosed as having retrolabyrinthine lesions by neurootological examinations; 29 patients with facial twitching or trigeminal neuralgia were classified in the second group. In the first group, air CT cisternography revealed 21 cases of small acoustic tumors including intracanalicular tumors. Additionally, several unexpected small lesions were detected in the cerebellopontine angle. These included small meningiomas, osteoma, osteogenic tumor, nodulated acoustic nerve in neurofibromatosis, primary acoustic nerve atrophy, adhesive arachnoiditis, elongated basilar artery and patulous acoustic meatus. In the second group, the causative artery of neurovascular compression at the nerve exit zone failed to be confirmed in many cases, but satisfactory preoperative information concerning nerves and vessels in the cerebellopontine angle were provided by air CT cisternography. The advantages and disadvantages of air CT cisternography and MRI-CT for the diagnosis of small lesions in the cerebellopontine angle are also discussed. (author).

  1. Interferometry of a reflective axicon surface with a small cone angle using an optical inner surface

    Science.gov (United States)

    Gao, Huimin; Zhang, Xiaodong; Fang, Fengzhou

    2017-09-01

    Reflective axicons, widely used in optical alignment and Bessel-Gauss beam generation, require a highly accurate cone angle and surface metrology. However, current methods focus on the cone angle measurement and it is still difficult to measure the surface of a reflective axicon with a small cone angle. An interferometer measurement method using an optical inner surface is proposed to obtain the surface and cone angle simultaneously. The optical axis of the axicon and the optical inner surface should align together and be parallel to the beam light from the interferometer. The interference fringe would be obtained by the optical system consisting of the axicon and the optical inner surface. The theoretical model is established and analyzed through ray tracing theory, and is verified by optical simulation software. Fabrication errors in the axicon and the inner surface, and misalignment of the measurement setup are investigated systematically and separated in the measurement process. In the experiments, the reflective axicon with a cone angle of about 90° was measured by the proposed method, the results of which show good agreement with a stylus profiler (Taylor-Hobson PGI 3D) in cone angle trend and generatrix error. Experimental results prove the feasibility of the proposed method. This economical and effective method can be widely used with all types of reflective axicons, and it can obtain the surface error map of the axicon as well as the inner cylinder at the same time. The uncertainty and resolution of the proposed method is based on the performance of the interferometer. The uncertainty of alignment angle errors is less than 10-10 rad; the lateral resolution is 53.8 µm.

  2. Small-angle neutron scattering studies from solutions of bovine nasal cartilage proteoglycan

    Science.gov (United States)

    Patel, A.; Stivala, S. S.; Damle, S. P.; Gregory, J. D.; Bunick, G. J.; Uberbacher, E. C.

    1986-02-01

    Small-angle neutron scattering, SANS, of the proteoglycan subunit of bovine nasal cartilage in 0.15 N LiC1 at 25°C yielded the radius of gyration, R g, radius of gyration of the cross-section, R q, persistence length, a *, and the molecular weight, M. The following values were obtained: M = 3.9 × 10 6, R g = 745 Å, R q = 34.6 Å and a * = 35.2 Å. These values compare favorably with those that were obtained from small angle X-ray scattering, SAXS, of a similar extract. The scattering curve of the proteoglycan subunit in D 2O showed a characteristic broad peak in the specified angular range similar to that observed from SAXS, thus confirming the polyelectrolyte nature of the proteoglycan.

  3. Measurement of the analysing power in proton–proton elastic scattering at small angles

    Directory of Open Access Journals (Sweden)

    Z. Bagdasarian

    2014-12-01

    Full Text Available The proton analysing power in p→p elastic scattering has been measured at small angles at COSY-ANKE at 796 MeV and five other beam energies between 1.6 and 2.4 GeV using a polarised proton beam. The asymmetries obtained by detecting the fast proton in the ANKE forward detector or the slow recoil proton in a silicon tracking telescope are completely consistent. Although the analysing power results agree well with the many published data at 796 MeV, and also with the most recent partial wave solution at this energy, the ANKE data at the higher energies lie well above the predictions of this solution at small angles. An updated phase shift analysis that uses the ANKE results together with the World data leads to a much better description of these new measurements.

  4. Small-angle scattering investigation of silica xerogels and sonogels prepared with ionic liquid pyridinium tetrafluoroborate

    Directory of Open Access Journals (Sweden)

    László Almásy

    2017-09-01

    Full Text Available Silica matrices were prepared via acid catalysed sol-gel processing augmented with sonocatalysis. As silica precursors, a mixture of tetra-functionalized alkoxide (TMOS and three-functionalized alkoxide methyl-trimethoxysilane (MTMS were employed. Ionic liquid N-butyl-3-methylpyridinium tetrafluoroborate ([bmPy][BF4], was used in various proportions, aiming to catalyse the sol-gel reactions, and to influence the mesoporous silica materials properties, serving as pore template. Small-angle neutron (SANS and small-angle X-ray scattering (SAXS techniques were used to explore the xerogels and sonogels microstructure evolution as a function of the IL/Si molar ratio. The results show a strong increase of the primary particle size under the influence of the ionic liquid. Ultrasonic agitation leads to further size increase by ca. 10%.

  5. Performance of silicon pixel detectors at small track incidence angles for the ATLAS Inner Tracker Upgrade

    CERN Document Server

    AUTHOR|(INSPIRE)INSPIRE-00232885; The ATLAS collaboration; Banerjee, Swagato; Brandt, Gerhard; Carney, Rebecca; Garcia-Sciveres, Maurice; Hard, Andrew; Kaplan, Laser Seymour; Kashif, Lashkar; Pranko, Aliaksandr; Rieger, Julia; Wolf, Julian Choate; Wu, Sau Lan; Yang, Hongtao

    2015-01-01

    In order to enable the ATLAS experiment to successfully track charged particles produced in high-energy collisions at the High-Luminosity Large Hadron Collider, the current ATLAS Inner Detector will be replaced by the Inner Tracker (ITk), entirely composed of silicon pixel and strip detectors. An extension of the tracking coverage of the ITk to very forward pseudorapidity values is proposed, using pixel modules placed in a long cylindrical layer around the beam pipe. The measurement of long pixel clusters, detected when charged particles cross the silicon sensor at small incidence angles, has potential to significantly improve the tracking efficiency, fake track rejection, and resolution of the ITk in the very forward region. The performance of state-of-the-art pixel modules at small track incidence angles is studied using test beam data collected at SLAC and CERN.

  6. Magnetic design of a spin-echo small-angle neutron-scattering instrument

    CERN Document Server

    Uca, O; Rekveldt, M T

    2003-01-01

    In a spin-echo small-angle neutron scattering instrument dipole magnets and guide field coils are used. The homogeneity of the fields should be sufficient to have linear labeling of the height with precession. Furthermore, the instrument must have a homogenous line integral over the beam cross-section. It is shown that line integral inhomogeneities are directly connected to field components perpendicular to the main field. The design parameters of these magnetic units of the setup are calculated.

  7. Kinetics of structural reorganizations in multilamellarphotosynthetic membranes monitored by small-angle neutronscattering

    DEFF Research Database (Denmark)

    Nagy, Gergely; Kovacs, Laszlo; Unnep, Renata

    2013-01-01

    We demonstrate the power of time-resolved small-angle neutron scattering experiments for the investigation of the structure and structural reorganizations of multilamellar photosynthetic membranes. In addition to briefly summarizing our results on thylakoid membranes isolated from higher plants...... and in unicellular organisms, we discuss the advantages and technical and methodological limitations of timeresolved SANS. We present a detailed and more systematical investigation of the kinetics of light-induced structural reorganizations in isolated spinach thylakoid membranes, which show how changes...

  8. Relationship between the atomic pair distribution function and small angle scattering: implications for modeling of nanoparticles

    OpenAIRE

    Farrow, Christopher L.; Billinge, Simon J. L.

    2008-01-01

    Here we show explicitly the relationship between the functions used in the atomic pair distribution function (PDF) method and those commonly used in small angle scattering (SAS) analyses. The origin of the sloping baseline, $-4\\pi r\\rho_0$, in PDFs of bulk materials is identified as originating from the SAS intensity that is neglected in PDF measurements. The non-linear baseline in nanoparticles has the same origin, and contains information about the shape and size of the nanoparticles.

  9. An innovative small angle slot divertor concept for long pulse advanced tokamaks

    Science.gov (United States)

    Guo, Houyang

    2017-10-01

    A new Small Angle Slot (SAS) divertor is being developed in DIII-D to address the challenge of efficient divertor heat dispersal at the relatively low plasma density required for non-inductive current drive in future advanced tokamaks. SAS features a small incident angle near the plasma strike point on the divertor target plate with a progressively opening slot. SOLPS (B2-Eirene) edge code analysis finds that SAS can achieve strong plasma cooling when the strike point is placed near the small angle target plate in the slot, leading to low electron temperature Te across the entire divertor target. This is enabled by strong coupling between a gas tight slot and directed neutral recycling by the small angle target to enhance neutral buildup near the target. SOLPS analysis reveals a strong correlation between Te and D2 density at the target for various divertor configurations including the flat target, slanted target, and lower single null divertor. The strong correlation suggests that achievement of low Te may reduce essentially to identifying the divertor baffle geometry that achieves the highest target gas density at a given upstream condition. The SAS divertor concept has recently been tested in DIII-D for a range of plasma configurations and conditions with precise control of slot strike point location. In confirmation of SOLPS predictions, a sharp transition is observed when the strike point is moved to the critical outer corner of SAS. A set of Langmuir probes imbedded in SAS show that the Te radial profile, which is peaked at the strike point when it is located away from the SAS corner, becomes low across the target when the strike point is located near the corner. With further increase in density, deep-slot detachment occurs with Te 1 eV, measured by the unique DIII-D divertor Thomson Scattering diagnostic. Work supported by US DOE under DE-FC02-04ER54698.

  10. Small-Angle Neutron Scattering Measurements of Magnetic Cluster Sizes in Magnetic Recording Disks

    Energy Technology Data Exchange (ETDEWEB)

    Toney, Michael F

    2003-06-17

    We describe Small Angle Neutron Scattering measurements of the magnetic cluster size distributions for several longitudinal magnetic recording media. We find that the average magnetic cluster size is slightly larger than the average physical grain size, that there is a broad distribution of cluster sizes, and that the cluster size is inversely correlated to the media signal-to-noise ratio. These results show that intergranular magnetic coupling in these media is small and they provide empirical data for the cluster-size distribution that can be incorporated into models of magnetic recording.

  11. Tunable moiré bands and strong correlations in small-twist-angle bilayer graphene

    Science.gov (United States)

    Kim, Kyounghwan; DaSilva, Ashley; Huang, Shengqiang; Fallahazad, Babak; Larentis, Stefano; Taniguchi, Takashi; Watanabe, Kenji; LeRoy, Brian J.; MacDonald, Allan H.; Tutuc, Emanuel

    2017-03-01

    According to electronic structure theory, bilayer graphene is expected to have anomalous electronic properties when it has long-period moiré patterns produced by small misalignments between its individual layer honeycomb lattices. We have realized bilayer graphene moiré crystals with accurately controlled twist angles smaller than 1° and studied their properties using scanning probe microscopy and electron transport. We observe conductivity minima at charge neutrality, satellite gaps that appear at anomalous carrier densities for twist angles smaller than 1°, and tunneling densities-of-states that are strongly dependent on carrier density. These features are robust up to large transverse electric fields. In perpendicular magnetic fields, we observe the emergence of a Hofstadter butterfly in the energy spectrum, with fourfold degenerate Landau levels, and broken symmetry quantum Hall states at filling factors ±1, 2, 3. These observations demonstrate that at small twist angles, the electronic properties of bilayer graphene moiré crystals are strongly altered by electron-electron interactions.

  12. Nanostructure surveys of macroscopic specimens by small-angle scattering tensor tomography

    Science.gov (United States)

    Liebi, Marianne; Georgiadis, Marios; Menzel, Andreas; Schneider, Philipp; Kohlbrecher, Joachim; Bunk, Oliver; Guizar-Sicairos, Manuel

    2015-11-01

    The mechanical properties of many materials are based on the macroscopic arrangement and orientation of their nanostructure. This nanostructure can be ordered over a range of length scales. In biology, the principle of hierarchical ordering is often used to maximize functionality, such as strength and robustness of the material, while minimizing weight and energy cost. Methods for nanoscale imaging provide direct visual access to the ultrastructure (nanoscale structure that is too small to be imaged using light microscopy), but the field of view is limited and does not easily allow a full correlative study of changes in the ultrastructure over a macroscopic sample. Other methods of probing ultrastructure ordering, such as small-angle scattering of X-rays or neutrons, can be applied to macroscopic samples; however, these scattering methods remain constrained to two-dimensional specimens or to isotropically oriented ultrastructures. These constraints limit the use of these methods for studying nanostructures with more complex orientation patterns, which are abundant in nature and materials science. Here, we introduce an imaging method that combines small-angle scattering with tensor tomography to probe nanoscale structures in three-dimensional macroscopic samples in a non-destructive way. We demonstrate the method by measuring the main orientation and the degree of orientation of nanoscale mineralized collagen fibrils in a human trabecula bone sample with a spatial resolution of 25 micrometres. Symmetries within the sample, such as the cylindrical symmetry commonly observed for mineralized collagen fibrils in bone, allow for tractable sampling requirements and numerical efficiency. Small-angle scattering tensor tomography is applicable to both biological and materials science specimens, and may be useful for understanding and characterizing smart or bio-inspired materials. Moreover, because the method is non-destructive, it is appropriate for in situ measurements and

  13. Note: Grazing incidence small and wide angle x-ray scattering combined with imaging ellipsometry

    Energy Technology Data Exchange (ETDEWEB)

    Koerstgens, V.; Meier, R.; Ruderer, M. A.; Guo, S.; Chiang, H.-Y.; Mueller-Buschbaum, P. [Technische Universitaet Muenchen, Physik-Department, Lehrstuhl fuer Funktionelle Materialien, James-Franck-Str. 1, 85748 Garching (Germany); Perlich, J.; Roth, S. V.; Gehrke, R. [HASYLAB, DESY, Notkestr. 85, 22607, Hamburg (Germany)

    2012-07-15

    The combination of grazing incidence small angle x-ray scattering (GISAXS) and grazing incidence wide angle x-ray scattering (GIWAXS) with optical imaging ellipsometry is presented as an upgrade of the available measurement techniques at the wiggler beamline BW4 of the Hamburger Synchrotronstrahlungslabor. The instrument is introduced with the description of the alignment procedure to assure the measurement of imaging ellipsometry and GISAXS/GIWAXS on the same sample spot. To demonstrate the possibilities of the new instrument examples of morphological investigation on films made of poly(3-hexylthiophene) and [6,6]-phenyl-C{sub 61} butyric acid methyl ester as well as textured poly(9,9-dioctylfluorene-alt-benzo-thia-diazole) are shown.

  14. Ni containing solid Kr bubbles studied with neutron depolarization and small-angle neutron scattering

    Energy Technology Data Exchange (ETDEWEB)

    Rosman, R.; Rekveldt, M.T. (Interfacultair Reactor Inst., Delft Univ. of Technology (Netherlands))

    1991-07-01

    Neutron depolarization (ND) and small-angle neutron scattering (SANS) experiments on Ni containing solid Kr bubbles are presented and discussed. The aim of the measurements is to study the effect of the Kr bubbles on the local magnetization. For the first time ND measurements in relatively large fields up to 80kA/m could be performed. However, the ND results do not yield information about the Kr bubbles. The SANS patterns at applied fields larger than 400kA/m are isotropic and are in agreement with a high fraction of small (radius {approx equal} 1.5nm) Kr bubbles. Also a small fraction of larger (radius > or approx. 15nm) Kr bubbles or other nuclear inhomogeneities is likely to be present. The magnetic scattering is in agreement with a local magnetization which is affected by the demagnetization fields of these inhomogeneities. (orig.).

  15. Solution structure and excitation energy transfer in phycobiliproteins of Acaryochloris marina investigated by small angle scattering.

    Science.gov (United States)

    Golub, M; Combet, S; Wieland, D C F; Soloviov, D; Kuklin, A; Lokstein, H; Schmitt, F-J; Olliges, R; Hecht, M; Eckert, H-J; Pieper, J

    2017-04-01

    The structure of phycobiliproteins of the cyanobacterium Acaryochloris marina was investigated in buffer solution at physiological temperatures, i.e. under the same conditions applied in spectroscopic experiments, using small angle neutron scattering. The scattering data of intact phycobiliproteins in buffer solution containing phosphate can be well described using a cylindrical shape with a length of about 225Å and a diameter of approximately 100Å. This finding is qualitatively consistent with earlier electron microscopy studies reporting a rod-like shape of the phycobiliproteins with a length of about 250 (M. Chen et al., FEBS Letters 583, 2009, 2535) or 300Å (J. Marquart et al., FEBS Letters 410, 1997, 428). In contrast, phycobiliproteins dissolved in buffer lacking phosphate revealed a splitting of the rods into cylindrical subunits with a height of 28Å only, but also a pronounced sample aggregation. Complementary small angle neutron and X-ray scattering experiments on phycocyanin suggest that the cylindrical subunits may represent either trimeric phycocyanin or trimeric allophycocyanin. Our findings are in agreement with the assumption that a phycobiliprotein rod with a total height of about 225Å can accommodate seven trimeric phycocyanin subunits and one trimeric allophycocyanin subunit, each of which having a height of about 28Å. The structural information obtained by small angle neutron and X-ray scattering can be used to interpret variations in the low-energy region of the 4.5K absorption spectra of phycobiliproteins dissolved in buffer solutions containing and lacking phosphate, respectively. Copyright © 2017 Elsevier B.V. All rights reserved.

  16. Investigation of nanoscale structures by small-angle X-ray scattering in a radiochromic dosimeter

    DEFF Research Database (Denmark)

    Skyt, Peter Sandegaard; Jensen, Grethe Vestergaard; Wahlstedt, Isak Hannes

    2014-01-01

    This study examines the nanoscale structures in a radiochromic dosimeter that was based on leuco-malachite-green dye and the surfactant sodium dodecyl sulfate (SDS) suspended in a gelatin matrix. Small-angle X-ray scattering was used to investigate the structures of a range of compositions...... of the dosimeter. When omitting gelatin, ellipsoidal micelles of SDS were formed with a core radius near 15 Å, an eccentricity of 1.6, and a head-group shell thickness near 7 Å. Gelatin significantly changed the micelles to a cylindrical shape with around three times lower core radius and four times larger shell...

  17. On the Casimir scaling violation in the cusp anomalous dimension at small angle

    Science.gov (United States)

    Grozin, Andrey; Henn, Johannes; Stahlhofen, Maximilian

    2017-10-01

    We compute the four-loop n f contribution proportional to the quartic Casimir of the QCD cusp anomalous dimension as an expansion for small cusp angle ϕ. This piece is gauge invariant, violates Casimir scaling, and first appears at four loops. It requires the evaluation of genuine non-planar four-loop Feynman integrals. We present results up to O({φ}^4) . One motivation for our calculation is to probe a recent conjecture on the all-order structure of the cusp anomalous dimension. As a byproduct we obtain the four-loop HQET wave function anomalous dimension for this color structure.

  18. Study of chemically unfolded {beta}-casein by means of small-angle neutron scattering

    Energy Technology Data Exchange (ETDEWEB)

    Aschi, Adel [Laboratoire de Physique de la Matiere Molle, Faculte des Sciences de Tunis, Campus Universitaire, 1060, Tunis (Tunisia)]. E-mail: aschi13@yahoo.fr; Gharbi, Abdelhafidh [Laboratoire de Physique de la Matiere Molle, Faculte des Sciences de Tunis, Campus Universitaire, 1060, Tunis (Tunisia); Daoud, Mohamed [Service de Physique de l' Etat Condense. CEA Saclay. 91191 Gif-sur-Yvette cedex (France); Douillard, Roger [Equipe de Biochimie des Macromolecules Vegetales, Centre de Recherche Agronomique, 2Esplanade R. Garros, BP 224, 51686 Reims cedex 2 (France); Calmettes, Patrick [Laboratoire Leon Brillouin, CEA Saclay, 91191 Gif-sur-Yvette cedex (France)

    2007-01-01

    {beta}-casein is a flexible amphiphilic milk protein which forms an unfolded conformation in presence of very high denaturant concentrations. The structure of {beta}-casein formed at the bulk was studied by small-angle neutron scattering (SANS). The value of the second virial coefficient of the protein solutions indicates that the interactions between the polypeptide chain and solvent are repulsive. The protein conformation is similar to an excluded volume chain. The corresponding values of the contour length, L, the statistical length, b and the apparent radius of the chain cross-section, R{sub c} are given.

  19. Small-angle and surface scattering from porous and fractal materials.

    Energy Technology Data Exchange (ETDEWEB)

    Sinha, S. K.

    1998-09-18

    We review the basic theoretical methods used to treat small-angle scattering from porous materials, treated as general two-phase systems, and also the basic experimental techniques for carrying out such experiments. We discuss the special forms of the scattering when the materials exhibit mass or surface fractal behavior, and review the results of recent experiments on several types of porous media and also SANS experiments probing the phase behavior of binary fluid mixtures or polymer solutions confined in porous materials. Finally, we discuss the analogous technique of off-specular scattering from surfaces and interfaces which is used to study surface roughness of various kinds.

  20. The structure of P85 pluronic block copolymer micelles determined by small-angle neutron scattering

    DEFF Research Database (Denmark)

    Pedersen, J.S.; Gerstenberg, M.C.

    2003-01-01

    The symmetric triblock copolymer Pluronic P85 with EO(25)PO(40)EO(25) has been studied by small-angle neutron scattering (SANS) at 50 and 60 degreesC at concentrations of 0.25-10 wt.% in D(2)O. The data are analyzed by a model based on Monte Carlo simulations. The micelles are modeled as having...... a spherical core of poly(propylene oxide) (PPO) with some water surrounded by a corona of the poly(ethylene oxide) (PEO) block. The latter are non-interacting and obey Gaussian statistics, but are expelled from the core region. The analysis shows that the micelles are fairly concentration and temperature...

  1. Small-angle neutron scattering from poly(NIPA-co-AMPS) gels

    DEFF Research Database (Denmark)

    Travas-Sejdic, J.; Easteal, A.; Knott, R.

    2000-01-01

    The microstructure of the poly( N-isopropylacrylamide-co-acrylamido- 2-methyl-1-propane sulphonic acid) gel, poly( NIPA-co-AMPS), was investigated as a function of temperature and cross-link density using the small angle neutron scattering technique. The sample temperature was varied in the range...... 30 to 55C. Two different behaviours of poly( NIPA-co-AMPS) gels were observed. At low temperature (30C), the magnitude of the scattered intensity increased with cross-link density suggesting that additional cross-links introduced more inhomogeneities in the gel network. At high temperatures the trend...

  2. Spatially resolved small-angle noncollinear interferometric autocorrelation of ultrashort pulses with microaxicon arrays.

    Science.gov (United States)

    Grunwald, R; Griebner, U; Nibbering, E T; Kummrow, A; Rini, M; Elsaesser, T; Kebbel, V; Hartmann, H J; Jüptner, W

    2001-11-01

    Small-angle, noncollinear, first- and second-order interferometric autocorrelation experiments with Ti:sapphire laser pulses of 9-80-fs duration have been performed with microaxicon arrays. Predictions of short-pulse spatial frequency effects were verified by comparison of interference patterns of single elements and matrices. An angular spectrum of Gaussian-shaped axicons was analyzed on the basis of linear refraction. Experimental data indicate contributions to autocorrelation by nonlinear refraction and travel-time differences. The influence of the spectral bandwidth was separated from the pulse-duration-dependent effects. Spatially resolved information about the coherence time was delivered by the multichannel structure.

  3. Cylindrical aggregates of chlorophylls studied by small-angle neutron scatter

    Energy Technology Data Exchange (ETDEWEB)

    Worcester, D.L. [Univ. of Missouri, Columbus, MO (United States); Katz, J.J. [Argonne National Laboratory, IL (United States)

    1994-12-31

    Neutron small-angle scattering has demonstrated tubular chlorophyll aggregates formed by self-assembly of a variety of chlorophyll types in nonpolar solvents. The size and other properties of the tubular aggregates can be accounted for by stereochemical properties of the chlorophyll molecules. Features of some of the structures are remarkably similar to light harvesting chlorophyll complexes in vivo, particularly for photosynthetic bacteria. These nanotube chlorophyll structures may have applications as light harvesting biomaterials where efficient energy transfer occurs from an excited state which is highly delocalized.

  4. High-frequency impedance of small-angle tapers and collimators

    Directory of Open Access Journals (Sweden)

    G. Stupakov

    2010-10-01

    Full Text Available Collimators and transitions in accelerator vacuum chambers often include small-angle tapering to lower the wakefields generated by the beam. While the low-frequency impedance is well described by Yokoya’s formula (for axisymmetric geometry, much less is known about the behavior of the impedance in the high-frequency limit. In this paper we develop an analytical approach to the high-frequency regime for round collimators and tapers. Our analytical results are compared with computer simulations using the code ECHO.

  5. Pinhole-type two-dimensional ultra-small-angle X-ray scattering on the micrometer scale

    Energy Technology Data Exchange (ETDEWEB)

    Kishimoto, Hiroyuki, E-mail: h-kishimoto.az@srigroup.co.jp [Sumitomo Rubber Industries Ltd, 2-1-1 Tsutsui, Chuo, Kobe, Hyogo 651-0071 (Japan); The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8561 (Japan); Shinohara, Yuya, E-mail: h-kishimoto.az@srigroup.co.jp [The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8561 (Japan); Suzuki, Yoshio; Takeuchi, Akihisa; Yagi, Naoto [Japan Synchrotron Radiation Research Institute, 1-1-1 Kouto, Sayo, Hyogo 679-5198 (Japan); Amemiya, Yoshiyuki [The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8561 (Japan)

    2013-11-02

    A pinhole-type ultra-small-angle X-ray scattering set-up that enlarges the accessible q-range to 0.25 µm{sup −1} is described. A pinhole-type two-dimensional ultra-small-angle X-ray scattering set-up at a so-called medium-length beamline at SPring-8 is reported. A long sample-to-detector distance, 160.5 m, can be used at this beamline and a small-angle resolution of 0.25 µm{sup −1} was thereby achieved at an X-ray energy of 8 keV.

  6. Small-incision cataract extraction combined trabeculectomy for primary angle-closure glaucoma with cataract

    Directory of Open Access Journals (Sweden)

    Yu-Feng Wu

    2014-09-01

    Full Text Available AIM: To observe the curative effect of treating small-incision cataract extraction by intraocular lens implantation combined with trabeculectomy for primary angle-closure glaucoma with cataract. METHODS: Totally 44 cases(52 eyesof primary angle-closure glaucoma combined with cataract were selected to undergo the combined surgery, in order to observe the patients' pre- and postoperative eyesights, intraocular pressures and the postoperative complications.RESULTS: The postoperative eyesight was improved significantly as compared with the preoperative eyesight. The intraocular pressure was declined dramatically. The result was of statistical significance(P0.05. All the 52 cases' surgeries were performed by the same surgeon. The surgeries were processed smoothly, with 6 postoperative eyes of anterior chamber inflammation cell response, 3 eyes of anterior chamber fibrinoid exudate, 2 eyes of shallow anterior chamber through mydriasis and treatment with glucocorticoids and non-steroidal eyedrops before absorption, and no complications like malignant glaucoma, cyclodialysis, etc. were reported through mydriasis and pressure bandaging before recovery.CONCLUSION: Treating the primary angle-closure glaucoma combined with cataract through the combined surgery has high reliability and desirable curative effect. The surgical method is simple to learn and applicable for promotion on the basic level.

  7. Structural defects in SiC single crystals studied by small-angle neutron scattering

    Energy Technology Data Exchange (ETDEWEB)

    Nasir Khan, M. [Physics Research Division, PINSTECH, P.O. Nilore, Islamabad (Pakistan)]. E-mail: nasir@pinstech.org.pk; Bashir, J. [Physics Research Division, PINSTECH, P.O. Nilore, Islamabad (Pakistan); Seong, Baek-Seok [Korea Atomic Energy Research Institute, P.O. Box 105, Yusong, Daejeon 305-600 (Korea, Republic of); Lee, Chang-Hee [Korea Atomic Energy Research Institute, P.O. Box 105, Yusong, Daejeon 305-600 (Korea, Republic of)

    2006-11-15

    Growth-induced structural defects such as hollow core super screw dislocation known as micropipes in silicon carbide single crystals grown by sublimation method are investigated. Electron microscopy as well as small-angle neutron scattering (SANS) techniques were used to resolve these defects in sizes. For SANS, scattering signals in the momentum transfer range 0.1-2.2 nm{sup -1} were recorded. This corresponds for the periodic structure to length scale from 3 to 60 nm approximately. Isotropic patterns were analyzed using spherical-shell model. The analyses showed that the small spherical defects are within a volume fraction less than 5% in these crystals. The change in the growth process such as growth rate and atmosphere showed no significant change in the sizes of these defects but has an effect on the distribution of these defects.

  8. Micelle structural studies on oil solubilization by a small-angle neutron scattering

    Science.gov (United States)

    Putra, Edy Giri Rachman; Seong, Baek Seok; Ikram, Abarrul

    2009-02-01

    A small-angle neutron scattering (SANS) technique was applied to reveal the micelle structural changes. The micelle structural changes of 0.3 M sodium dodecyl sulfate (SDS) concentration by addition of various oil, i.e. n-hexane, n-octane, and n-decane up to 60% (v/v) have been investigated. It was found that the size, aggregation number and the structures of the micelles changed exhibiting that the effective charge on the micelle decreases with an addition of oil. There was a small increase in minor axis of micelle while the correlation peak shifted to a lower momentum transfer Q and then to higher Q by a further oil addition.

  9. 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 VV mode with the polarizer and analyzer parallel to each other and the HV mode having them perpendicular to each other. Using rotational and translational diffusion coefficients obtained under the HV mode yielded a nanocellulose length qualitatively consistent with that observed by TEM, whereas the length derived by the translational diffusion coefficient under the VV mode appeared to be overestimated.

  10. Neutron Imaging of Laser Melted SS316 Test Objects with Spatially Resolved Small Angle Neutron Scattering

    Directory of Open Access Journals (Sweden)

    Adam J. Brooks

    2017-12-01

    Full Text Available A novel neutron far field interferometer is explored for sub-micron porosity detection in laser sintered stainless steel alloy 316 (SS316 test objects. The results shown are images and volumes of the first quantitative neutron dark-field tomography at various autocorrelation lengths, ξ . In this preliminary work, the beam defining slits were adjusted to an uncalibrated opening of 0.5 mm horizontal and 5 cm vertical; the images are blurred along the vertical direction. In spite of the blurred attenuation images, the dark-field images reveal structural information at the micron-scale. The topics explored include: the accessible size range of defects, potentially 338 nm to 4.5 μ m, that can be imaged with the small angle scattering images; the spatial resolution of the attenuation image; the maximum sample dimensions compatible with interferometry optics and neutron attenuation; the procedure for reduction of the raw interferogram images into attenuation, differential phase contrast, and small angle scattering (dark-field images; and the role of neutron far field interferometry in additive manufacturing to assess sub-micron porosity.

  11. 3 DOF Spherical Pendulum Oscillations with a Uniform Slewing Pivot Center and a Small Angle Assumption

    Directory of Open Access Journals (Sweden)

    Alexander V. Perig

    2014-01-01

    Full Text Available The present paper addresses the derivation of a 3 DOF mathematical model of a spherical pendulum attached to a crane boom tip for uniform slewing motion of the crane. The governing nonlinear DAE-based system for crane boom uniform slewing has been proposed, numerically solved, and experimentally verified. The proposed nonlinear and linearized models have been derived with an introduction of Cartesian coordinates. The linearized model with small angle assumption has an analytical solution. The relative and absolute payload trajectories have been derived. The amplitudes of load oscillations, which depend on computed initial conditions, have been estimated. The dependence of natural frequencies on the transport inertia forces and gravity forces has been computed. The conservative system, which contains first time derivatives of coordinates without oscillation damping, has been derived. The dynamic analogy between crane boom-driven payload swaying motion and Foucault’s pendulum motion has been grounded and outlined. For a small swaying angle, good agreement between theoretical and averaged experimental results was obtained.

  12. Insights into molecular architecture of terpenes using small angle neutron scattering

    Science.gov (United States)

    Rai, Durgesh K.; Annamraju, Aparna; Pingali, Sai Venkatesh; O'Neill, Hugh M.; Mewalal, Ritesh; Gunter, Lee E.; Tuskan, Gerald A.

    Understanding macromolecular architectures is vital to engineering prospective terpene candidates for advanced biofuels. Eucalyptus plants store terpenes in specialized cavity-like structures in the leaves called oil glands, which comprises of volatile (VTs) and non-volatile (NVTs) terpenes. Using small-angle neutron scattering, we have investigated the structure and phase behavior of the supramolecular assembly formed by Geranyl beta-D-glucoside (GDG), a NVT and compare the results with that of beta-octyl glucoside (BOG). The formation of micellar structures was observed in the concentration range of 0.5-5 v/v% in water using small angle neutron scattering (SANS) where Schultz sphere model was used in quantifying structural parameters of micelles. SANS studies determine that GDG and BOG behave like amphiphiles forming micellar structures in aqueous solution. The micelles swell upon addition of alpha-Pinene (AP) indicating partition to the core region of the micelles. The general behavior of the micellar growth after partitioning of AP to form thermodynamically stable sizes varies with the NVT concentration. Our studies reveal that the presence of steric hindrance in the GDG via the unsaturated bonds could help stabilize VTs inside the oil glands. LDRD project LOIS ID 7428, SNS, CSMB, HFIR, ORNL, DOE Office of Science User Facilities.

  13. Small angle scattering methods to study porous materials under high uniaxial strain

    Energy Technology Data Exchange (ETDEWEB)

    Le Floch, Sylvie, E-mail: sylvie.le-floch@univ-lyon1.fr; Balima, Félix; Pischedda, Vittoria; Legrand, Franck; San-Miguel, Alfonso [Institut Lumière Matière, UMR5306 Université Lyon 1-CNRS, Université de Lyon, 69622 Villeurbanne Cedex (France)

    2015-02-15

    We developed a high pressure cell for the in situ study of the porosity of solids under high uniaxial strain using neutron small angle scattering. The cell comprises a hydraulically actioned piston and a main body equipped with two single-crystal sapphire windows allowing for the neutron scattering of the sample. The sample cavity is designed to allow for a large volume variation as expected when compressing highly porous materials. We also implemented a loading protocol to adapt an existing diamond anvil cell for the study of porous materials by X-ray small angle scattering under high pressure. The two techniques are complementary as the radiation beam and the applied pressure are in one case perpendicular to each other (neutron cell) and in the other case parallel (X-ray cell). We will illustrate the use of these two techniques in the study of lamellar porous systems up to a maximum pressure of 0.1 GPa and 0.3 GPa for the neutron and X-ray cells, respectively. These devices allow obtaining information on the evolution of porosity with pressure in the pore dimension subdomain defined by the wave-numbers explored in the scattering process. The evolution with the applied load of such parameters as the fractal dimension of the pore-matrix interface or the apparent specific surface in expanded graphite and in expanded vermiculite is used to illustrate the use of the high pressure cells.

  14. A LabVIEW based experiment system for the efficient collection and analysis of cyclic voltametry and electrode charge capacity measurements.

    Science.gov (United States)

    Detlefsen, D; Hu, Z; Troyk, P R

    2006-01-01

    Cyclic voltametry and recording of stimulation electrode voltage excursions are two critical methods of measurement for understanding the performance of implantable electrodes. Because implanted electrodes cannot easily be replaced, it is necessary to have an a-priori understanding of an electrode's implanted performance and capabilities. In-vitro exhaustive tests are often needed to quantify an electrodes performance. Using commonly available equipment, the human labor cost to conduct this work is immense. Presented is an automated experiment system that is highly configurable that can efficiently conduct a battery of repeatable CV and stimulation recording measurements. Results of preparing 96 electrodes prior to an animal implantation are also discussed.

  15. Small-angle techniques for the asymptotic analysis of X-ray diffraction peaks

    Energy Technology Data Exchange (ETDEWEB)

    Ciccariello, S. (Padua Univ. (Italy). Dipt. di Fisica ' G. Galilei' )

    1990-03-01

    Any wide-angle X-ray scattering (WAXS) peak, relevant to a powder sample of crystallites with negligible internal disorder, is the Fourier transform of the so-called oriented stick probability function (oSPF) of the filled part of the sample, with the stick orientated along the reflexion direction. From this observation the following consequences are obtained: The correlation function used in small-angle X-ray scattering (SAXS) is the average of the former oSPF's over all possible stick orientations; any peak profile asymptotically vanishes as S{sub r}h{sup -2}, where S{sub r} is the (specific) area of the interphase surface presented by the sample along the reflexion direction; oscillatory deviations, behaving as S{sub r,parallel}cos (hL)h{sup -2}, are present only when a subset (having area S{sub r,parallel}) of the interface, after having been translated by L along the reflexion direction, superposes on itself; the angularity of the interphase surface can be measured by a natural modification of the Porod integral relation. For samples really isotropic, the above quantities should not depend on the reflexion direction and thus they should be equal to those measured by SAXS experiments. These results are applied to three ideal isotropic powder samples made up, respectively, of monodisperse spherical, cubic and cylindrical crystallites as well as to the analysis of two WAXS peaks diffracted by two real samples of zirconia powders. (orig.).

  16. Small angle X-ray scattering studies of reverse micelles in supercritical fluids

    Energy Technology Data Exchange (ETDEWEB)

    Pfund, D.M.; Fulton, J.L.

    1994-10-01

    The nature of aggregates formed in a supercritical fluid determines its solvent power and selectivity. Small angle X-ray scattering (SAXS) is a powerful tool for studying the properties of aggregates with sizes in the 10{angstrom} to 200{angstrom} range. It is also useful in studying those interparticle interactions which operate over a similar distance. The authors have used SAXS to examine the aggregates formed in pure fluids, in mixtures and in fluid/surfactant/water systems. The scattered intensity as a function of angle depends on the geometry, polydispersity, X-ray contrast, and interaction strength of the particles as well as on the phase behavior of the system. In this paper the authors present the results of modeling the X-ray scattering from AOT/water reverse micelles in supercritical propane and in propane/carbon dioxide mixtures. They examine the effect of dilution with CO{sub 2} anti-solvent on the phase behavior of the system and on the strength of intermicellar attractions. A better understanding of these systems must be obtained before the applications of supercritical reverse micelle systems to extractions, reactions, and enhanced oil recovery can be fully developed.

  17. 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.

  18. Small-angle x-ray scattering study on the structure of microcrystalline and nanofibrillated cellulose

    Science.gov (United States)

    Leppänen, Kirsi; Pirkkalainen, Kari; Penttilä, Paavo; Sievänen, Jenni; Kotelnikova, Nina; Serimaa, Ritva

    2010-10-01

    The effects of different solvents on the structure of microcrystalline and nanofibrillated cellulose (MCC, NFC) were studied using small-angle x-ray scattering (SAXS). MCC was immersed in water, ethanol, and acetone, and NFC was immersed only in water and ethanol, but studied also in the form of foam-like water-NFC-gel in wet, air-dried and re-wet states. The solvent affected the average chord length, which reveals the typical length scale of the structure of the sample: 2.4 ± 0.1 nm was obtained for MCC-water, 2.5 ± 0.1 nm for re-wet NFC-gel, 1.6 ± 0.1 nm for MCC-ethanol, 1.2 ± 0.1 nm for NFC-ethanol, and 1.3 ± 0.1 nm for MCC-acetone. The specific surface of cellulose increased strongly when MCC and NFC were immersed in the solvents compared to dry cellulose. The specific surface of cellulose was determined to be larger for NFC-water than MCC-water, and slightly larger for dry NFC powder than for dry MCC, which can be explained by the fact that the width of cellulose crystallites perpendicular to the cellulose chain direction was slightly larger in MCC than in NFC on the basis of wide-angle x-ray scattering results.

  19. Monomeric Amyloid Beta Peptide in Hexafluoroisopropanol Detected by Small Angle Neutron Scattering.

    Directory of Open Access Journals (Sweden)

    Bo Zhang-Haagen

    Full Text Available Small proteins like amyloid beta (Aβ monomers are related to neurodegenerative disorders by aggregation to insoluble fibrils. Small angle neutron scattering (SANS is a nondestructive method to observe the aggregation process in solution. We show that SANS is able to resolve monomers of small molecular weight like Aβ for aggregation studies. We examine Aβ monomers after prolonged storing in d-hexafluoroisopropanol (dHFIP by using SANS and dynamic light scattering (DLS. We determined the radius of gyration from SANS as 1.0±0.1 nm for Aβ1-40 and 1.6±0.1 nm for Aβ1-42 in agreement with 3D NMR structures in similar solvents suggesting a solvent surface layer with 5% increased density. After initial dissolution in dHFIP Aβ aggregates sediment with a major component of pure monomers showing a hydrodynamic radius of 1.8±0.3 nm for Aβ1-40 and 3.2±0.4 nm for Aβ1-42 including a surface layer of dHFIP solvent molecules.

  20. Gracing incidence small angle neutron scattering of incommensurate magnetic structures in MnSi thin films

    Energy Technology Data Exchange (ETDEWEB)

    Wiedemann, Birgit; Pfleiderer, Christian; Boeni, Peter [Physik Department, Technische Universitaet Muenchen (Germany); Zhang, Shilei; Hesjedal, Thorsten [Clarendon Laboratory, Department of Physics, University of Oxford (United Kingdom); Khaydukov, Yury; Soltwedel, Olaf; Keller, Thomas [Max-Planck-Institut fuer Festkoerperforschung (Germany); Max Planck Society, Outstation at FRM-II (Germany); Muehlbauer, Sebastian [Forschungsneutronenquelle Heinz Maier Leibnitz, Technische Universitaet Muenchen (Germany); Chacon, Alfonso [Physik Department, Technische Universitaet Muenchen (Germany); Forschungsneutronenquelle Heinz Maier Leibnitz, Technische Universitaet Muenchen (Germany)

    2015-07-01

    The topological stability of skyrmions in bulk samples of MnSi and the observation of spin transfer torque effects at ultra-low current densities have generated great interest in skyrmions in chiral magnets as a new route towards next generation spintronics devices. Yet, the formation of skyrmions in MBE grown thin films of MnSi reported in the literature is highly controversial. We report gracing incidence small angle neutron scattering (GISANS) of the magnetic order in selected thin films of MnSi grown by state of the art MBE techniques. In combination with polarised neutron reflectometry (PNR) and magnetisation measurements of the same samples our data provide direct reciprocal space information of the incommensurate magnetic order, clarifying the nature of magnetic phase diagram.

  1. Small-angle x-ray scattering study of polymer structure: Carbosilane dendrimers in hexane solution

    Science.gov (United States)

    Shtykova, E. V.; Feigin, L. A.; Volkov, V. V.; Malakhova, Yu. N.; Streltsov, D. R.; Buzin, A. I.; Chvalun, S. N.; Katarzhanova, E. Yu.; Ignatieva, G. M.; Muzafarov, A. M.

    2016-09-01

    The three-dimensional organization of monodisperse hyper-branched macromolecules of regular structure—carbosilane dendrimers of zero, third, and sixth generations—has been studied by small-angle X-ray scattering (SAXS) in solution. The use of modern methods of SAXS data interpretation, including ab initio modeling, has made it possible to determine the internal architecture of the dendrimers in dependence of the generation number and the number of cyclosiloxane end groups (forming the shell of dendritic macromolecules) and show dendrimers to be spherical. The structural results give grounds to consider carbosilane dendrimers promising objects for forming crystals with subsequent structural analysis and determining their structure with high resolution, as well as for designing new materials to be used in various dendrimer-based technological applications.

  2. Robust, high-throughput solution structural analyses by small angle X-ray scattering (SAXS)

    Energy Technology Data Exchange (ETDEWEB)

    Hura, Greg L.; Menon, Angeli L.; Hammel, Michal; Rambo, Robert P.; Poole II, Farris L.; Tsutakawa, Susan E.; Jenney Jr, Francis E.; Classen, Scott; Frankel, Kenneth A.; Hopkins, Robert C.; Yang, Sungjae; Scott, Joseph W.; Dillard, Bret D.; Adams, Michael W. W.; Tainer, John A.

    2009-07-20

    We present an efficient pipeline enabling high-throughput analysis of protein structure in solution with small angle X-ray scattering (SAXS). Our SAXS pipeline combines automated sample handling of microliter volumes, temperature and anaerobic control, rapid data collection and data analysis, and couples structural analysis with automated archiving. We subjected 50 representative proteins, mostly from Pyrococcus furiosus, to this pipeline and found that 30 were multimeric structures in solution. SAXS analysis allowed us to distinguish aggregated and unfolded proteins, define global structural parameters and oligomeric states for most samples, identify shapes and similar structures for 25 unknown structures, and determine envelopes for 41 proteins. We believe that high-throughput SAXS is an enabling technology that may change the way that structural genomics research is done.

  3. Characterisation of creep cavitation damage in a stainless steel pressure vessel using small angle neutron scattering

    CERN Document Server

    Bouchard, P J; Treimer, W

    2002-01-01

    Grain-boundary cavitation is the dominant failure mode associated with initiation of reheat cracking, which has been widely observed in austenitic stainless steel pressure vessels operating at temperatures within the creep range (>450 C). Small angle neutron scattering (SANS) experiments at the LLB PAXE instrument (Saclay) and the V12 double-crystal diffractometer of the HMI-BENSC facility (Berlin) are used to characterise cavitation damage (in the size range R=10-2000 nm) in a variety of creep specimens extracted from ex-service plant. Factors that affect the evolution of cavities and the cavity-size distribution are discussed. The results demonstrate that SANS techniques have the potential to quantify the development of creep damage in type-316H stainless steel, and thereby link microstructural damage with ductility-exhaustion models of reheat cracking. (orig.)

  4. Time-resolved small-angle neutron scattering of a micelle-to-vesicle transition

    Energy Technology Data Exchange (ETDEWEB)

    Egelhaaf, S.U. [Institut Max von Laue - Paul Langevin (ILL), 38 -Grenoble (France); Schurtenberger, P. [Eidgenoessische Technische Hochschule, Zurich (Switzerland)

    1997-04-01

    Amphiphilic molecules spontaneously self-assemble in solution to form a variety of aggregates. Only limited information is available on the kinetics of the structural transitions as well as on the existence of non-equilibrium or metastable states. Aqueous mixtures of lecithin and bile salt are very interesting biological model-systems which exhibit a spontaneous transition from polymer-like mixed micelles to vesicles upon dilution. The small-angle neutron scattering (SANS) instrument D22, with its very high neutron flux and the broad range of scattering vectors covered in a single instrumental setting, allowed us for the first time to perform time-resolved scattering experiments in order to study the micelle-to-vesicle transition. The temporal evolution of the aggregate structures were followed and detailed information was obtained even on molecular length-scales. (author). 5 refs.

  5. Small Angle Neutron Scattering for the Detection of Branching in Worm-Like Micellar Systems

    Science.gov (United States)

    Vogtt, Karsten; Rai, Durgesh; Beaucage, Gregory

    2014-03-01

    Micellar solutions can exhibit a broad variety of phase structure as a function of counter ion content, surfactant concentration, and the presence of ternary components. Under some conditions extended cylindrical structures that display persistence and other chain features of polymers are produced. These worm-like micelles (WLMs) can form branched structures that dynamically change under shear and even in quiescent conditions. The rheology of these branched WLMs is strongly dependent on migration of the branch points, and the dynamics of branch formation and removal. We have recently developed a scattering model for branched polyolefins and other topologically complex materials that can quantify the branching density, branch length, branch functionality and the hyperbranch (branch-on-branch) content of polymers. Using small angle neutron scattering these parameters are determined for model emulsions with varying surfactant and salt concentrations.

  6. A new small-angle neutron scattering spectrometer at China Mianyang research reactor

    Science.gov (United States)

    Peng, Mei; Sun, Liangwei; Chen, Liang; Sun, Guangai; Chen, Bo; Xie, Chaomei; Xia, Qingzhong; Yan, Guanyun; Tian, Qiang; Huang, Chaoqiang; Pang, Beibei; Zhang, Ying; Wang, Yun; Liu, Yaoguang; Kang, Wu; Gong, Jian

    2016-02-01

    A new pinhole small-angle neutron scattering (SANS) spectrometer, installed at the cold neutron source of the 20 MW China Mianyang Research Reactor (CMRR) in the Institute of Nuclear Physics and Chemistry, China Academy of Engineering Physics, has been put into use since 2014. The spectrometer is equipped with a multi-blade mechanical velocity selector, a multi-beam collimation system, and a two-dimensional He-3 position sensitive neutron detector. The q-range of the spectrometer covers from 0.01 nm-1 to 5.0 nm-1. In this paper, the design and characteristics of the SANS spectrometer are described. The q-resolution calculations, together with calibration measurements of silver behenate and a dispersion of nearly monodisperse poly-methyl-methacrylate nanoparticles indicate that our SANS spectrometer has a good performance and is now in routine service.

  7. Use of Small-Angle Neutron Scattering in Testing the Stability of Ferrofluids

    CERN Document Server

    Balasoiu, M; Avdeev, M V; Aksenov, V L; Khokhryakov, A A; Bica, L D; Hasegan, D; Török, G; Rosta, L

    2004-01-01

    Stability of ferrofluids - colloidal solutions of magnetic particles covered with surfactants - is the main characteristic that determines the possibility to exploit ferrofluids in different industrial and biomedical applications. Small-angle neutron scattering (SANS) can be effectively used to reveal the aggregation and its change with time in ferrofluids under the action of magnetic field. Despite the fact that in most cases the detailed description of scattering is complicated, one can judge whether a ferrofluid is stable or not by simple analysis of changes in the mean scattering intensity. The advantages of SANS are that industrial samples can be tested without any additional modifications, as well as the real-time experiments with any magnetic load can be easily performed. Examples for a number of ferrofluids are given.

  8. Online ion-exchange chromatography for small-angle X-ray scattering.

    Science.gov (United States)

    Hutin, Stephanie; Brennich, Martha; Maillot, Benoit; Round, Adam

    2016-10-01

    Biological small-angle X-ray scattering (BioSAXS) is a powerful technique to determine the solution structure, particle size, shape and surface-to-volume ratio of macromolecules. However, a drawback is that the sample needs to be monodisperse. To ensure this, size-exclusion chromatography (SEC) has been implemented on many BioSAXS beamlines. Here, the integration of ion-exchange chromatography (IEC) using both continuous linear and step gradients on a beamline is described. Background subtraction for continuous gradients by shifting a reference measurement and two different approaches for step gradients, which are based on interpolating between two background measurements, are discussed. The results presented here serve as a proof of principle for online IEC and subsequent data treatment.

  9. Small Angle X-ray Diffraction Study of DNA—Cationic Liposomes Aggregates

    Science.gov (United States)

    Pullmannová, Petra; Uhríková, Daniela; Funari, Sergio S.; Lacko, Ivan; Devínsky, Ferdinand; Balgavý, Pavol

    2010-01-01

    The microstructure of DNA—dioleoylphosphatidylethanolamine (DOPE)—propane-1,3-diyl-bis(dodecyldimethylammonium bromide) (C3GS12) aggregates as a function of the C3GS12:DOPE molar ratio and temperature was investigated using small angle X-ray diffraction. At 20° C, we observe a condensed lamellar phase (Lαc) with the lattice parameter d˜6.8-6.2 nm and the DNA—DNA distance dDNA˜5.8-3.2 nm decreasing with increasing content of C3GS12 in the phospholipid bilayer. Increase in temperature induces a phase transition from Lαc phase to condensed inverted hexagonal phase (HIIc). The temperature of the Lαc→HIIc phase transition increases with increasing C3GS12:DOPE molar ratio.

  10. Polymer boosting effect in the droplet phase studied by small-angle neutron scattering

    CERN Document Server

    Frielinghaus, H; Allgaier, J; Richter, D; Jakobs, B; Sottmann, T; Strey, R

    2002-01-01

    Small-angle neutron-scattering experiments were performed in order to obtain the six partial scattering functions of a droplet microemulsion containing water, decane, C sub 1 sub 0 E sub 4 surfactant and PEP sub 5 -PEO sub 8 sub 0. We systematically varied the contrast around the polymer contrast, where only the polymer becomes visible, and we also measured bulk and film contrasts. With the singular value decomposition method we could extract the desired six partial scattering functions from the 15 measured spectra. We find a sphere-shell-shell structure of the droplets, where the innermost sphere consists of oil, the middle shell of surfactant and the outer shell is a depletion zone where the polymer is almost not present. (orig.)

  11. Wide-Area Assessment of Aperiodic Small Signal Rotor Angle Stability in Real-Time

    DEFF Research Database (Denmark)

    Jóhannsson, Hjörtur; Nielsen, Arne Hejde; Østergaard, Jacob

    2013-01-01

    This paper presents the details of a new real-time stability assessment method. The method assesses a particular mechanism of stability: each generator’s capability to generate sufficient steady state electromechanical torque. The lack of sufficient steady state torque causes aperiodic increase...... in rotor angle and a loss of synchronism, referred to as aperiodic small signal instability. The paper provides the theoretical background of the method and an analytical assessment criterion. Furthermore, a mathematical mapping of the generators’ operating points that enables informative visualization...... of multiple operating points is derived in the paper. Finally, results from time-domain simulation of instability scenarios in the Nordic32 test system are presented and results used for testing the assessment method. The results illustrate the method’s capability to efficiently identify the location...

  12. Small angle neutron scattering study on short and long chain phosphatidylcholine mixture in trehalose solution

    Energy Technology Data Exchange (ETDEWEB)

    Takahashi, Hiroshi [Department of Physics, Gunma University, Maebashi, Gunma (Japan)

    2001-03-01

    Trehalose protects cells and proteins against various stresses due to low temperatures or dryness. In order to clarify the molecular mechanism of cryoprotective function of trehalose, we have studied the interaction between trehalose and phosphatidylcholine (PC) which is a main lipid component of cell membranes. In this study, the structural change of a binary PC mixture by the presence of trehalose was investigated by means of small angle neutron scattering. The PC binary mixture studied contains dihexanoyl-PC (diC{sub 6}PC) and dihexadecy-PC (DHPC). The former has short hydrocarbon chains and the latter has long hydrocarbon chains. The scattering profiles from the DHPC/diC{sub 6}PC mixture were changed, depending on trehalose concentrations. This change can be interpreted as suggesting that the presence of trehalose reduces the interfacial area between water and PCs. (author)

  13. Quantitative evaluation of statistical errors in small-angle X-ray scattering measurements.

    Science.gov (United States)

    Sedlak, Steffen M; Bruetzel, Linda K; Lipfert, Jan

    2017-04-01

    A new model is proposed for the measurement errors incurred in typical small-angle X-ray scattering (SAXS) experiments, which takes into account the setup geometry and physics of the measurement process. The model accurately captures the experimentally determined errors from a large range of synchrotron and in-house anode-based measurements. Its most general formulation gives for the variance of the buffer-subtracted SAXS intensity σ2(q) = [I(q) + const.]/(kq), where I(q) is the scattering intensity as a function of the momentum transfer q; k and const. are fitting parameters that are characteristic of the experimental setup. The model gives a concrete procedure for calculating realistic measurement errors for simulated SAXS profiles. In addition, the results provide guidelines for optimizing SAXS measurements, which are in line with established procedures for SAXS experiments, and enable a quantitative evaluation of measurement errors.

  14. ORNL 10-m small-angle X-ray scattering camera

    Energy Technology Data Exchange (ETDEWEB)

    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/sup 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/sup 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.

  15. Self-assembly of designed coiled coil peptides studied by small-angle X-ray scattering and analytical ultracentrifugation

    DEFF Research Database (Denmark)

    Malik, Leila; Nygaard, Jesper; Christensen, Niels Johan

    2013-01-01

    , they are promising tools for the construction of nanomaterials. Small-angle X-ray scattering (SAXS) has emerged as a new biophysical technique for elucidation of protein topology. Here, we describe a systematic study of the self-assembly of a small ensemble of coiled coil sequences using SAXS and analytical...

  16. Small-scale screening method for low-viscosity antibody solutions using small-angle X-ray scattering.

    Science.gov (United States)

    Fukuda, Masakazu; Watanabe, Atsushi; Hayasaka, Akira; Muraoka, Masaru; Hori, Yuji; Yamazaki, Tadao; Imaeda, Yoshimi; Koga, Akiko

    2017-03-01

    In this study, we investigated the concentration range in which self-association starts to form in humanized IgG monoclonal antibody (mAb) solutions. Furthermore, on the basis of the results, we developed a practical method of screening for low-viscosity antibody solutions by using small-angle X-ray scattering (SAXS) measurements utilizing small quantities of samples. With lower-viscosity mAb3, self-association was not detected in the range of 1-80mg/mL. With higher-viscosity mAb1, on the other hand, self-association was detected in the range of 10-20mg/mL and was clearly enhanced by a decrease in temperature. The viscosities of mAb solutions at 160, 180, and 200mg/mL at 25°C quantitatively correlated very well with the particle size parameters obtained by SAXS measurements of mAb solutions at 15mg/mL at 5°C. The quantity of mAb sample required for the SAXS measurements was only 0.15mg, which is about one-hundredth of that required for actual viscosity measurements at a high concentration, and such quantities could be available even at an early stage of development. In conclusion, the SAXS analysis method proposed in this study is a valuable tool for the development of concentrated mAb therapeutics with high manufacturability and high usability for subcutaneous injection. Copyright © 2016 Elsevier B.V. All rights reserved.

  17. Improving small-angle X-ray scattering data for structural analyses of the RNA world.

    Science.gov (United States)

    Rambo, Robert P; Tainer, John A

    2010-03-01

    Defining the shape, conformation, or assembly state of an RNA in solution often requires multiple investigative tools ranging from nucleotide analog interference mapping to X-ray crystallography. A key addition to this toolbox is small-angle X-ray scattering (SAXS). SAXS provides direct structural information regarding the size, shape, and flexibility of the particle in solution and has proven powerful for analyses of RNA structures with minimal requirements for sample concentration and volumes. In principle, SAXS can provide reliable data on small and large RNA molecules. In practice, SAXS investigations of RNA samples can show inconsistencies that suggest limitations in the SAXS experimental analyses or problems with the samples. Here, we show through investigations on the SAM-I riboswitch, the Group I intron P4-P6 domain, 30S ribosomal subunit from Sulfolobus solfataricus (30S), brome mosaic virus tRNA-like structure (BMV TLS), Thermotoga maritima asd lysine riboswitch, the recombinant tRNA(val), and yeast tRNA(phe) that many problems with SAXS experiments on RNA samples derive from heterogeneity of the folded RNA. Furthermore, we propose and test a general approach to reducing these sample limitations for accurate SAXS analyses of RNA. Together our method and results show that SAXS with synchrotron radiation has great potential to provide accurate RNA shapes, conformations, and assembly states in solution that inform RNA biological functions in fundamental ways.

  18. Topological investigation of electronic silicon nanoparticulate aggregates using ultra-small-angle X-ray scattering

    Science.gov (United States)

    Jonah, E. O.; Britton, D. T.; Beaucage, P.; Rai, D. K.; Beaucage, G.; Magunje, B.; Ilavsky, J.; Scriba, M. R.; Härting, M.

    2012-11-01

    The network topology of two types of silicon nanoparticles, produced by high energy milling and pyrolysis of silane, in layers deposited from inks on permeable and impermeable substrates has been quantitatively characterized using ultra-small-angle X-ray scattering, supported by scanning electron microscopy observations. The milled particles with a highly polydisperse size distribution form agglomerates, which in turn cluster to form larger aggregates with a very high degree of aggregation. Smaller nanoparticles with less polydisperse size distribution synthesized by thermal catalytic pyrolysis of silane form small open clusters. The Sauter mean diameters of the primary particles of the two types of nanoparticles were obtained from USAXS particle volume to surface ratio, with values of 41 and 21 nm obtained for the high energy milled and pyrolysis samples, respectively. Assuming a log-normal distribution of the particles, the geometric standard deviation of the particles was calculated to be 1.48 for all the samples, using parameters derived from the unified fit to the USAXS data. The flow properties of the inks and substrate combination lead to quantitative changes in the mean particle separation, with slowly curing systems with good capillary flow resulting in denser networks with smaller aggregates and better contact between particles.

  19. Spin-Echo Small Angle Neutron Scattering analysis of liposomes and bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Heijkamp, Leon F van; Sevcenco, Ana-Maria; Abou, Diane; Luik, Remko van; Krijger, Gerard C; Schepper, Ignatz M de; Wolterbeek, Bert; Bouwman, Wim G [Faculty of Applied Sciences, Department of Radiation, Radionuclides and Reactors, Delft University of Technology, Mekelweg 15, 2629 JB Delft (Netherlands); Hagedoorn, Peter-Leon [Faculty of Applied Sciences, Department of Biotechnology, Delft University of Technology, Julianalaan 67, 2628 BC Delft (Netherlands); Koning, Gerben A, E-mail: l.f.vanheijkamp@tudelft.n, E-mail: w.g.bouwman@tudelft.n [Laboratory Experimental Surgical Oncology, Section Surgical Oncology, Department of Surgery, Erasmus Medical Center, POBox 1738, 3000 DR Rotterdam (Netherlands)

    2010-10-01

    Two types of liposomes, commonly used in drug delivery studies, and E. coli bacteria, all prepared in H{sub 2}O, were resuspended in D{sub 2}O and measured with Small Angle Spin-Echo Neutron Scattering (SESANS). Modeling was performed using correlation functions for solid spheres and hollow spheres. The signal strength and curve shape were more indicative of hollow particles, indicating that the H{sub 2}O-D{sub 2}O exchange occurred too fast to be observed with the available time resolution. Fitting the particle diameter and membrane thickness of the hollow sphere model to the data, gave results which were in good agreement with Dynamic Light Scattering (DLS) data and literature, showing as a proof-of-principle that SESANS is able to investigate such systems. SESANS may become a good alternative to conventional tritium studies or a tool with which to study intracellular vesicle transport phenomena, with possible in vivo applications. Calculations show that a substantial change in numbers of a mixed system of small and large biological particles should be observable. A possible application is the destruction by external means of great numbers of liposomes in the presence of tumor cells for triggered drug release in cancer treatment. Since SESANS is both non-invasive and non-destructive and can handle relatively thick samples, it could be a useful addition to more conventional techniques.

  20. Structure parameters of synaptic vesicles quantified by small-angle x-ray scattering.

    Science.gov (United States)

    Castorph, Simon; Riedel, Dietmar; Arleth, Lise; Sztucki, Michael; Jahn, Reinhard; Holt, Matthew; Salditt, Tim

    2010-04-07

    Synaptic vesicles (SVs) are small, membrane-bound organelles that are found in the synaptic terminal of neurons, and which are crucial in neurotransmission. After a rise in internal [Ca(2+)] during neuronal stimulation, SVs fuse with the plasma membrane releasing their neurotransmitter content, which then signals neighboring neurons. SVs are subsequently recycled and refilled with neurotransmitter for further rounds of release. Recently, tremendous progress has been made in elucidating the molecular composition of SVs, as well as putative protein-protein interactions. However, what is lacking is an empirical description of SV structure at the supramolecular level-which is necessary to enable us to fully understand the processes of membrane fusion, retrieval, and recycling. Using small-angle x-ray scattering, we have directly investigated the size and structure of purified SVs. From this information, we deduced detailed size and density parameters for the protein layers responsible for SV function, as well as information about the lipid bilayer. To achieve a convincing model fit, a laterally anisotropic structure for the protein shell is needed, as a rotationally symmetric density profile does not explain the data. Not only does our model confirm many of the preexisting ideas concerning SV structure, but also for the first time, to our knowledge, it indicates structural refinements, such as the presence of protein microdomains. Copyright (c) 2010 Biophysical Society. Published by Elsevier Inc. All rights reserved.

  1. Structure Parameters of Synaptic Vesicles Quantified by Small-Angle X-Ray Scattering

    Science.gov (United States)

    Castorph, Simon; Riedel, Dietmar; Arleth, Lise; Sztucki, Michael; Jahn, Reinhard; Holt, Matthew; Salditt, Tim

    2010-01-01

    Synaptic vesicles (SVs) are small, membrane-bound organelles that are found in the synaptic terminal of neurons, and which are crucial in neurotransmission. After a rise in internal [Ca2+] during neuronal stimulation, SVs fuse with the plasma membrane releasing their neurotransmitter content, which then signals neighboring neurons. SVs are subsequently recycled and refilled with neurotransmitter for further rounds of release. Recently, tremendous progress has been made in elucidating the molecular composition of SVs, as well as putative protein-protein interactions. However, what is lacking is an empirical description of SV structure at the supramolecular level—which is necessary to enable us to fully understand the processes of membrane fusion, retrieval, and recycling. Using small-angle x-ray scattering, we have directly investigated the size and structure of purified SVs. From this information, we deduced detailed size and density parameters for the protein layers responsible for SV function, as well as information about the lipid bilayer. To achieve a convincing model fit, a laterally anisotropic structure for the protein shell is needed, as a rotationally symmetric density profile does not explain the data. Not only does our model confirm many of the preexisting ideas concerning SV structure, but also for the first time, to our knowledge, it indicates structural refinements, such as the presence of protein microdomains. PMID:20371319

  2. Synchrotron small-angle X-ray scattering studies of hemoglobin nonaggregation confined inside polymer capsules.

    Science.gov (United States)

    Mandal, Soumit S; Bhaduri, Satarupa; Amenitsch, Heinz; Bhattacharyya, Aninda J

    2012-08-16

    The effect of confinement on the structure of hemoglobin (Hb) within polymer capsules was investigated here. Hemoglobin transformed from an aggregated state in solution to a nonaggregated state when confined inside the polymer capsules. This was directly confirmed using synchrotron small-angle X-ray scattering (SAXS) studies. The radius of gyration (R(g)) and polydispersity (p) of the proteins in the confined state were smaller compared to those in solution. In fact, the R(g) value is very similar to theoretical values obtained using protein structures generated from the Protein Databank. In the temperature range (25-85 °C, Tm 59 °C), the R(g) values for the confined Hb remained constant. This observation is in contrary to the increasing R(g) values obtained for the bare Hb in solution. This suggested higher thermal stability of Hb when confined inside the polymer capsule than when in solution. Changes in protein configuration were also reflected in the protein function. Confinement resulted in a beneficial enhancement of the electroactivity of Hb. While Hb in solution showed dominance of the cathodic process (Fe(3+) → Fe(2+)), efficient reversible Fe(3+)/Fe(2+) redox response is observed in the case of the confined Hb. This has important protein functional implications. Confinement allows the electroactive heme to take up positions favorable for various biochemical activities such as sensing of analytes of various sizes from small to macromolecules and controlled delivery of drugs.

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

    Energy Technology Data Exchange (ETDEWEB)

    Grant, Thomas D. [Hauptman–Woodward Medical Research Institute, 700 Ellicott Street, Buffalo, NY 14203 (United States); Luft, Joseph R. [Hauptman–Woodward Medical Research Institute, 700 Ellicott Street, Buffalo, NY 14203 (United States); SUNY Buffalo, 700 Ellicott Street, Buffalo, NY 14203 (United States); Carter, Lester G.; Matsui, Tsutomu; Weiss, Thomas M.; Martel, Anne [Stanford Synchrotron Radiation Lightsource, 2575 Sand Hill Road, MS69, Menlo Park, CA 94025 (United States); Snell, Edward H., E-mail: esnell@hwi.buffalo.edu [Hauptman–Woodward Medical Research Institute, 700 Ellicott Street, Buffalo, NY 14203 (United States); SUNY Buffalo, 700 Ellicott Street, Buffalo, NY 14203 (United States)

    2015-01-01

    A set of quantitative techniques is suggested for assessing SAXS data quality. These are applied in the form of a script, SAXStats, to a test set of 27 proteins, showing that these techniques are more sensitive than manual assessment of data quality. 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.

  4. Nondestructive Evaluation on Hydrided LWR Fuel Cladding by Small Angle Incoherent Neutron Scattering of Hydrogen

    Energy Technology Data Exchange (ETDEWEB)

    Yan, Yong [ORNL; Qian, Shuo [ORNL; Littrell, Ken [ORNL; Parish, Chad M [ORNL; Bell, Gary L [ORNL; Plummer, Lee K [ORNL

    2013-01-01

    A non-destructive neutron scattering method was developed to precisely measure the uptake of total hydrogen in nuclear grade Ziraloy-4 cladding. The hydriding apparatus consists of a closed stainless steel vessel that contains Zr alloy specimens and H gas. By controlling the initial H gas pressure in the vessel and the temperature profile, target H concentrations from tens of ppm to a few thousands of wppm have been successfully achieved. Following H charging, the H content of the hydrided specimens was measured using the vacuum hot extraction method (VHE), by which the samples with desired H concentration were selected for the neutron study. Small angle neutron incoherent scattering (SANIS) were performed in the High Flux Isotope Reactor at Oak Ridge national Laboratory (ORNL). Our study indicates that a very small amount ( 20 ppm) H in commercial Zr cladding can be measured very accurately in minutes for a wide range of H concentration by a nondestructive method. The H distribution in a tube sample was obtained by scaling the neutron scattering rate with a factor, which is determined by calibration process with direct chemical analysis method on the specimen. This scale factor can be used for future test with unknown H concentration, thus provide a nondestructive method for absolute H concentration determination.

  5. Planar small-angle x-ray scattering imaging of phantoms and biological samples

    Science.gov (United States)

    Choi, M.; Badano, A.

    2017-04-01

    Coherent small-angle x-ray scattering (SAXS) provides molecular and nanometer-scale structural information. By capturing SAXS data at multiple locations across a sample, we obtained planar images and observed improved contrast given by the difference in the material scattering cross sections. We use phantoms made with 3D printing techniques, with tissue-mimicking plastic (PMMA), and with a highly scattering reference material (AgBe), which were chosen because of their well characterized scattering cross section to demonstrate and characterize the planar imaging of a laboratory SAXS system. We measure 1.07 and 2.14 nm-1 angular intensity maps for AgBe, 9.5 nm-1 for PMMA, and 12.3 nm-1 for Veroclear. The planar SAXS images show material discrimination based on their cross sectional features. The image signal-to-noise ratio (SNR) of each q image was dependent on exposure time and x-ray flux. We observed a lower SNR (91 ± 48) at q angles where no characteristic peaks for either material exist. To improve the visualization of the acquired data by utilizing all q-binned data, we describe a weighted-sum presentation method with a priori knowledge of relevant cross sections to improve the SNR (10 000 ± 6400) over the SNR from a single q-image at 1.07 nm-1 (1100 ± 620). In addition, we describe planar SAXS imaging of a mouse brain slice showing differentiation of tissue types as compared to a conventional absorption-based x-ray imaging technique.

  6. 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.

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

    Science.gov (United States)

    Settens, Charles M.

    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, H 2 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 CD-SEM, 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.

  8. A triple axis double crystal multiple reflection camera for ultra small angle X-ray scattering

    Science.gov (United States)

    Lambard, Jacques; Lesieur, Pierre; Zemb, Thomas

    1992-06-01

    To extend the domain of small angle X-ray scattering requires multiple reflection crystals to collimate the beam. A double crystal, triple axis X-ray camera using multiple reflection channel cut crystals is described. Procedures for measuring the desmeared scattering cross-section on absolute scale are described as well as the measurement from several typical samples : fibrils of collagen, 0.3 μm diameter silica spheres, 0.16 μm diameter interacting latex spheres, porous lignite coal, liquid crystals in a surfactant-water system, colloidal crystal of 0.32 μm diameter silica spheres. L'extension du domaine de diffusion des rayons-X vers les petits angles demande l'emploi de cristaux à réflexions multiples pour collimater le faisceau. Nous décrivons une caméra à rayons-X à trois axes où les réflexions multiples sont réalisées dans deux cristaux à gorge. Nous donnons ensuite les procédures de déconvolution pour obtenir la section efficace de diffusion en échelle absolue, ainsi que les résultats des mesures effectuées avec plusieurs échantillons typiques : fibres de collagène, sphères de silice de 0,3 μm de diamètre, sphères de latex de 0,16 μm de diamètre en interaction, charbon lignite poreux, cristaux liquides formés dans un système eau-tensioactif, solution colloïdale de sphères de silice de 0,32 μm de diamètre.

  9. Structural characterization of a polymer substituted fullerene (flagellene) by small angle neutron scattering

    Energy Technology Data Exchange (ETDEWEB)

    Affholter, K.A.; Bunick, G.J.; Wignall, G.D. [Oak Ridge National Lab., TN (United States); Desimone, J.M.; Hunt, M.O. Jr.; Menceloglu, Y.Z.; Samulski, E.T. [North Carolina Univ., Chapel Hill, NC (United States). Dept. of Chemistry

    1994-12-31

    Small-angle neutron scattering (SANS) can structurally characterize fullerenes in solvents with strong SANS contrast (e.g. CS{sub 2}). Deuterated solvents (e.g. toluene-d{sub 8}) have a high scattering length density (SLD), which is close to that of C{sub 60} and C{sub 70} moieties. Hence, there is virtually no SANS contrast with the solvent and these particles are practically ``invisible`` in such media. On the other hand, the negative scattering length of hydrogen means that the SLD of H{sup 1}-containing materials is much lower, so they have strong contrast with toluene-d{sub 8}. Thus, SANS makes it possible to study the size and shapes of modified buckyballs such as the polymer-substituted fullerenes, or flagellenes. These consist of C{sub 60} cores to which 1-4 polystryene chains (with a molecular weight, MW {approx_equal} 2000) are attached. The extrapolated cross section at zero angle of scatter [d{Sigma}/d{Omega}(0)] is a function of the number of pendant chains, so SANS can be used to assess the number of ``arms`` which are covalently attached to the fullerene ``sphere.`` Close agreement ({plus_minus}4%) between measured and calculated values of d{Sigma}/d{Omega}(0) along with independent estimates of the radius of gyration (R{sub g}) and second virial coefficient (A{sub 2}) for a calibration linear polystyrene sample serves as a cross check on the validity of this methodology.

  10. Justification and implementation of the coordinate method among potentially possible precise methods for measuring angles between axes of small-angle beams

    Science.gov (United States)

    Kudryavtsev, M. D.

    2017-08-01

    A series of studies devoted to the theoretical justification and development of methods and tools for angular measurements based on the use of multiple sources of optical beams with a small angular aperture is continued. The source used in this study is a holographic prism: a fluorite single crystal with a system of superimposed holograms recorded in its bulk, which generates a series of diffracted small-angle beams in the form of a flat fan under illumination by a reference laser. This fan has a high spatial stability, including constancy of angles between any pair of fan beams in a wide range of external conditions. Based on the previously introduced notion of an effective beam axis, potential exact methods for measuring angles between fan beams are considered, and a coordinate method using a coordinate measuring machine and a CCD recorder is substantiated and implemented. The accuracy of the proposed method is analyzed. It is shown that its errors can potentially be reduced to a level of 1″ or even less.

  11. 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

  12. Refraction and ultra-small-angle scattering of X-rays in a single-crystal diamond compound refractive lens.

    Science.gov (United States)

    Gasilov, S; Mittone, A; Dos Santos Rolo, T; Polyakov, S; Zholudev, S; Terentyev, S; Blank, V; Bravin, A; Baumbach, T

    2017-11-01

    In this work a double-crystal setup is employed to study compound refractive lenses made of single-crystal diamond. The point spread function of the lens is calculated taking into account the lens transmission, the wavefront aberrations, and the ultra-small-angle broadening of the X-ray beam. It is shown that, similarly to the wavefront aberrations, the ultra-small-angle scattering effects can significantly reduce the intensity gain and increase the focal spot size. The suggested approach can be particularly useful for the characterization of refractive X-ray lenses composed of many tens of unit lenses.

  13. Gluon transport equation in the small angle approximation and the onset of Bose–Einstein condensation

    Energy Technology Data Exchange (ETDEWEB)

    Blaizot, Jean-Paul [Institut de Physique Théorique, CNRS/URA 2306, CEA Saclay, F-91191 Gif-sur-Yvette (France); Liao, Jinfeng [Physics Dept. and CEEM, Indiana University, 2401 N Milo B. Sampson Lane, Bloomington, IN 47408 (United States); RIKEN BNL Research Center, Bldg. 510A, Brookhaven National Laboratory, Upton, NY 11973 (United States); McLerran, Larry [Physics Dept., Bldg. 510A, Brookhaven National Laboratory, Upton, NY 11973 (United States); RIKEN BNL Research Center, Bldg. 510A, Brookhaven National Laboratory, Upton, NY 11973 (United States); Physics Department, China Central Normal University, Wuhan (China)

    2014-11-15

    To understand the evolution of a dense system of gluons, such as those produced in the early stages of ultra-relativistic heavy ion collisions, is an important and challenging problem. We describe the approach to thermal equilibrium using the small angle approximation for gluon scattering in a Boltzmann equation that includes the effects of Bose statistics. The role of Bose statistical factors in amplifying the rapid growth of the population of the soft modes is essential. With these factors properly taken into account, one finds that elastic scattering alone provides an efficient mechanism for populating soft modes, and in fact leads to rapid infrared local thermalization. Furthermore, recent developments suggest that high initial overpopulation plays a key role and may lead to dynamical Bose–Einstein condensation. The kinetics of condensation is an interesting problem in itself. By solving the transport equation for initial conditions with a large enough initial phase-space density the equilibrium state contains a Bose condensate, and we present numerical evidence that such over-occupied systems reach the onset of Bose–Einstein condensation in a finite time. It is also found that the approach to condensation is characterized by a scaling behavior. Finally we discuss a number of extensions of the present study.

  14. Magnetic particles studied with neutron depolarization and small-angle neutron scattering

    Energy Technology Data Exchange (ETDEWEB)

    Rosman, R.

    1991-04-23

    Materials containing magnetic single-domain particles, referred to as `particulate media`, have been studied using neutron depolarization (ND) and small-angle neutron scattering (SANS). In a ND experiment the polarization vector of a polarized neutron beam is analyzed after transmission through a magnetic medium. Such an analysis in general yields the correlation length of variations in magnetic induction along the neutron path (denoted `magnetic correlation length`), mean orientation of these variations and mean magnetic induction. In a SANS experiment, information about nuclear and magnetic inhomogeneities in the medium is derived from the broadening of a generally unpolarized neutron beam due to scattering by these inhomogeneities. Spatial and magnetic microstructure of a variety of particulate media have been studied using ND and/or SANS, by determination of the magnetic or nuclear correlation length in these media in various magnetic states. This thesis deals with the ND theory and its application to particulate media. ND and SANS experiments on a variety of particulate media are discussed. (author). 178 refs., 97 figs., 8 tabs.

  15. Magnetic particles studied with neutron depolarization and small-angle neutron scattering

    Energy Technology Data Exchange (ETDEWEB)

    Rosman, R.

    1991-04-23

    Materials containing magnetic single-domain particles, referred to as 'particulate media', have been studied using neutron depolarization (ND) and small-angle neutron scattering (SANS). In a ND experiment the polarization vector of a polarized neutron beam is analyzed after transmission through a magnetic medium. Such an analysis in general yields the correlation length of variations in magnetic induction along the neutron path (denoted 'magnetic correlation length'), mean orientation of these variations and mean magnetic induction. In a SANS experiment, information about nuclear and magnetic inhomogeneities in the medium is derived from the broadening of a generally unpolarized neutron beam due to scattering by these inhomogeneities. Spatial and magnetic microstructure of a variety of particulate media have been studied using ND and/or SANS, by determination of the magnetic or nuclear correlation length in these media in various magnetic states. This thesis deals with the ND theory and its application to particulate media. ND and SANS experiments on a variety of particulate media are discussed. (author). 178 refs., 97 figs., 8 tabs.

  16. Characterization of Nanoclay Orientation in Polymer Nanocomposite Film by Small-angle X-ray Scattering

    Energy Technology Data Exchange (ETDEWEB)

    P Nawani; C Burger; L Rong; B Chu; B Hsiao; A Tsou; W Weng

    2011-12-31

    The orientation distribution of layer-shaped nanoclays (e.g. organoclays and pristine clays) dispersed in a polymer matrix is an important parameter to control the properties of polymer nanocomposites. In this study, we demonstrate that the use of multi-directional 2-D small-angleX-rayscattering (SAXS) can quantitatively describe the orientation distribution of organoclays (e.g. Cloisite C20A) in melt-pressed nanocompositefilms, containing ethylene-vinyl acetate (EVA) copolymers as polymer matrices. Different weight fractions of organoclays were used to alter the orientation profile of nanocompositefilms, in which the dispersion and morphology of organoclays were also characterized by complementary 2-D and 3-D transmission electron microscopy (TEM). All nanocomposites exhibited mixed intercalation/exfoliation clay morphology, where the intercalated structure possessed partial orientation parallel to the in-plane direction of the film. The higher content of the clay loading showed a higher clay orientation. A simple analytical scheme for SAXS data analysis to determine the orientation parameter (P{sub 2}) was demonstrated, the results of which are in agreement with the gas permeation properties of the nanocompositefilms.

  17. Survey of background scattering from materials found in small-angle neutron scattering.

    Science.gov (United States)

    Barker, J G; Mildner, D F R

    2015-08-01

    Measurements and calculations of beam attenuation and background scattering for common materials placed in a neutron beam are presented over the temperature range of 300-700 K. Time-of-flight (TOF) measurements have also been made, to determine the fraction of the background that is either inelastic or quasi-elastic scattering as measured with a 3He detector. Other background sources considered include double Bragg diffraction from windows or samples, scattering from gases, and phonon scattering from solids. Background from the residual air in detector vacuum vessels and scattering from the 3He detector dome are presented. The thickness dependence of the multiple scattering correction for forward scattering from water is calculated. Inelastic phonon background scattering at small angles for crystalline solids is both modeled and compared with measurements. Methods of maximizing the signal-to-noise ratio by material selection, choice of sample thickness and wavelength, removal of inelastic background by TOF or Be filters, and removal of spin-flip scattering with polarized beam analysis are discussed.

  18. Small-angle neutron scattering study of a dense microemulsion system formed with an ionic liquid.

    Science.gov (United States)

    Kang, T; Qian, S; Smith, G S; Do, C; Heller, W T

    2017-10-11

    Mixtures of water, octane and 1-octanol with 1-tetradecyl-3-methylimidazolium chloride (C14MIM·Cl), often referred to as a surface active ionic liquid (SAIL), form water-in-oil microemulsions that have potential application as extraction media for various metal ions. Here, we present a structural study by small-angle neutron scattering (SANS) of dense microemulsions formed by surfactant-rich mixtures of these four compounds to understand how the SAIL can be used to tune the structures and properties of the microemulsions. The SANS experiments revealed that the microemulsions formed are composed of two phases, a water-in-oil microemulsion and a bicontinuous microemulsion, which becomes the dominant phase at high surfactant concentration. In this concentration regime, the surfactant film becomes more rigid, having a higher bending modulus that results from the parallel stacking of the imidazolium ring of the SAIL. At lower surfactant concentrations, the molecular packing of the SAIL does not change with the water content of the microemulsion. The results presented here correlate well with previously observed changes in the interaction between the IL cation and metal ions (Y. Tong, L. Han and Y. Yang, Ind. Eng. Chem. Res., 2012, 51, 16438-16443), while the capacity of the microemulsion system for water remains high enough for using the system as an extraction medium.

  19. Small angle X-ray study of cellulose macromolecules produced by tunicates and bacteria.

    Science.gov (United States)

    Khandelwal, Mudrika; Windle, Alan H

    2014-07-01

    The organisation of poly-glucan chains into cellulose macromolecular microfibrils has been studied using small angle X-ray scattering (SAXS). Three kinds of cellulose - bacterial cellulose (BC), nata-de-coco (NdC) (food grade bacterial cellulose) and tunicate cellulose (TC) have been investigated. Given the large ambiguity in literature on the microfibril dimensions owing to different methods and data analysis strategies, a method to extract dimensions of cellulose microfibrils using SAXS has been shown, which was found to be consistent across all the samples. The results have been verified with microscopy data. Two populations of microfibrils with different cross-section dimensions were identified. The dimensions of the rectangular cross-sections of BC were found to be 32nm by 16nm and 21nm by 10nm. The dimensions for NdC were calculated to be 25nm×8nm and 14nm×6nm and that for TC were determined to be 25nm×10nm and 15nm×8nm. Copyright © 2014 Elsevier B.V. All rights reserved.

  20. Investigation of Monodisperse Dendrimeric Polysaccharide Nanoparticle Dispersions Using Small Angle Neutron Scattering

    Science.gov (United States)

    Atkinson, John; Nickels, Jonathan; Papp-Szabo, Erzsi; Katsaras, John; Dutcher, John

    2015-03-01

    Phytoglycogen is a highly branched polysaccharide that is very similar to the energy storage molecule glycogen. We have isolated monodisperse phytoglycogen nanoparticles from corn and these particles are attractive for applications in the cosmetic, food and beverage, and biomedical industries. Many of these promising applications are due to the special interaction between the nanoparticles and water, which results in: (1) high solubility; (2) low viscosity and high stability in aqueous dispersions; and (3) a remarkable capacity to sequester and retain water. Our rheology measurements indicate that the nanoparticles behave like hard spheres in water, with the viscosity diverging for concentrations >25% (w/w). Because of this, aqueous suspensions of phytoglycogen provide an ideal platform for detailed testing of theories of colloidal glasses and jamming. To further explore the interaction of the phytoglycogen particles and water, we have performed small angle neutron scattering (SANS) measurements on the Extended Q-Range SANS (EQ-SANS) diffractometer at the Spallation Neutron Source at Oak Ridge National Laboratory. Measurements performed on phytoglycogen dispersions in mixtures of hydrogenated and deuterated water have allowed us to determine the particle size and average particle spacing as a function of the phytoglycogen concentration in the limits of dilute and concentrated dispersions.

  1. Quantitative evaluation of statistical errors in small-angle X-ray scattering measurements

    Energy Technology Data Exchange (ETDEWEB)

    Sedlak, Steffen M.; Bruetzel, Linda K.; Lipfert, Jan (LMU)

    2017-03-29

    A new model is proposed for the measurement errors incurred in typical small-angle X-ray scattering (SAXS) experiments, which takes into account the setup geometry and physics of the measurement process. The model accurately captures the experimentally determined errors from a large range of synchrotron and in-house anode-based measurements. Its most general formulation gives for the variance of the buffer-subtracted SAXS intensity σ2(q) = [I(q) + const.]/(kq), whereI(q) is the scattering intensity as a function of the momentum transferq;kand const. are fitting parameters that are characteristic of the experimental setup. The model gives a concrete procedure for calculating realistic measurement errors for simulated SAXS profiles. In addition, the results provide guidelines for optimizing SAXS measurements, which are in line with established procedures for SAXS experiments, and enable a quantitative evaluation of measurement errors.

  2. 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.

  3. Microstructure of 3D-Printed Polymer Composites Investigated by Small-Angle Neutron Scattering

    Science.gov (United States)

    Kang, Tae Hui; Compton, Brett G.; Heller, William T.; Urban, Voker S.; Duty, Chad E.; Do, Changwoo

    Polymer composites printed from the large scale printer at Manufacturing Demonstration Facility at Oak Ridge National Laboratory have been investigated by small-angle neutron scattering (SANS). For the Acrylonitrile Butadiene Styrene (ABS)/Carbon Fiber (CF) composites, the microstructure of polymer domains and the alignment of CF have been characterized across the layer from the printed piece. CF shows strong anisotropic alignment along the printing direction due to the flow of polymer melt at the nozzle. Order parameter of the anisotropy which ranges from -0.11 to -0.06 exhibits strong correlation with the position within the layer: stronger alignment near the layer interface. It is also confirmed that the existence of CF reduces the polymer domain correlation length significantly and reinforces the mechanical strength of the polymer composites. For the Epoxy/nano-clay platelet composites, the effect of processing condition, nozzle size, and the addition of the another filler, Silicon Carbide (SC), have been investigated by SANS. Nano-clay platelet shows strong anisotropic alignment along the printing direction as well. Order parameter of the anisotropy varies according to nozzle size and presence of the SC, and difference disappears at high Q region. Scientific User Facilities Division and Materials Sciences and Energy Division, Office of Basic Energy Sciences, U.S. Department of Energy.

  4. Resolution of ab initio shapes determined from small-angle scattering

    Directory of Open Access Journals (Sweden)

    Anne T. Tuukkanen

    2016-11-01

    Full Text Available Spatial resolution is an important characteristic of structural models, and the authors of structures determined by X-ray crystallography or electron cryo-microscopy always provide the resolution upon publication and deposition. Small-angle scattering of X-rays or neutrons (SAS has recently become a mainstream structural method providing the overall three-dimensional structures of proteins, nucleic acids and complexes in solution. However, no quantitative resolution measure is available for SAS-derived models, which significantly hampers their validation and further use. Here, a method is derived for resolution assessment for ab initio shape reconstruction from scattering data. The inherent variability of the ab initio shapes is utilized and it is demonstrated how their average Fourier shell correlation function is related to the model resolution. The method is validated against simulated data for proteins with known high-resolution structures and its efficiency is demonstrated in applications to experimental data. It is proposed that henceforth the resolution be reported in publications and depositions of ab initio SAS models.

  5. Measurement of the running of the QED coupling in small-angle Bhabha scattering at LEP

    CERN Document Server

    Abbiendi, G.; Akesson, P.F.; Alexander, G.; Anagnostou, G.; Anderson, K.J.; Asai, S.; Axen, D.; Bailey, I.; Barberio, E.; Barillari, T.; Barlow, R.J.; Batley, R.J.; Bechtle, P.; Behnke, T.; Bell, Kenneth Watson; Bell, P.J.; Bella, G.; Bellerive, A.; Benelli, G.; Bethke, S.; Biebel, O.; Boeriu, O.; Bock, P.; Boutemeur, M.; Braibant, S.; Brown, Robert M.; Burckhart, H.J.; Campana, S.; Capiluppi, P.; Carnegie, R.K.; Carter, A.A.; Carter, J.R.; Chang, C.Y.; Charlton, D.G.; Ciocca, C.; Csilling, A.; Cuffiani, M.; Dado, S.; Dallavalle, G.M.; De Roeck, A.; De Wolf, E.A.; Desch, K.; Dienes, B.; Dubbert, J.; Duchovni, E.; Duckeck, G.; Duerdoth, I.P.; Etzion, E.; Fabbri, F.; Ferrari, P.; Fiedler, F.; Fleck, I.; Ford, M.; Frey, A.; Gagnon, P.; Gary, John William; Geich-Gimbel, C.; Giacomelli, G.; Giacomelli, P.; Giacomelli, R.; Giunta, Marina; Goldberg, J.; Gross, E.; Grunhaus, J.; Gruwe, M.; Gunther, P.O.; Gupta, A.; Hajdu, C.; Hamann, M.; Hanson, G.G.; Harel, A.; Hauschild, M.; Hawkes, C.M.; Hawkings, R.; Hemingway, R.J.; Herten, G.; Heuer, R.D.; Hill, J.C.; Horvath, D.; Igo-Kemenes, P.; Ishii, K.; Jeremie, H.; Jovanovic, P.; Junk, T.R.; Kanzaki, J.; Karlen, D.; Kawagoe, K.; Kawamoto, T.; Keeler, R.K.; Kellogg, R.G.; Kennedy, B.W.; Kluth, S.; Kobayashi, T.; Kobel, M.; Komamiya, S.; Kramer, T.; Krieger, P.; von Krogh, J.; Kuhl, T.; Kupper, M.; Lafferty, G.D.; Landsman, H.; Lanske, D.; Lellouch, D.; Lettso, J.; Levinson, L.; Lillich, J.; Lloyd, S.L.; Loebinger, F.K.; Lu, J.; Ludwig, A.; Ludwig, J.; Mader, W.; Marcellini, S.; Martin, A.J.; Mashimo, T.; Mattig, Peter; McKenna, J.; McPherson, R.A.; Meijers, F.; Menges, W.; Merritt, F.S.; Mes, H.; Meyer, Niels T.; Michelini, A.; Mihara, S.; Mikenberg, G.; Miller, D.J.; Mohr, W.; Mori, T.; Mutter, A.; Nagai, K.; Nakamura, I.; Nanjo, H.; Neal, H.A.; Nisius, R.; ONeale, S.W.; Oh, A.; Oreglia, M.J.; Orito, S.; Pahl, C.; Pasztor, G.; Pater, J.R.; Pilcher, J.E.; Pinfold, J.; Plane, David E.; Pooth, O.; Przybycien, M.; Quadt, A.; Rabbertz, K.; Rembser, C.; Renkel, P.; Roney, J.M.; Runge, K.; Sachs, K.; Saeki, T.; Sarkisyan, E.K.G.; Schaile, A.D.; Schaile, O.; Scharff-Hansen, P.; Schieck, J.; Schorner-Sadenius, T.; Schroder, Matthias; Schumacher, M.; Seuster, R.; Shears, T.G.; Shen, B.C.; Sherwood, P.; Skuja, A.; Smith, A.M.; Sobie, R.; Soldner-Rembold, S.; Spano, F.; Stahl, A.; Strom, David M.; Strohmer, R.; Tarem, S.; Tasevsky, M.; Teuscher, R.; Thomson, M.A.; Torrence, E.; Toya, D.; Tran, P.; Trigger, I.; Trocsanyi, Z.; Tsur, E.; Turner-Watson, M.F.; Ueda, I.; Ujvari, B.; Vollmer, C.F.; Vannerem, P.; Vertesi, R.; Verzocchi, M.; Voss, H.; Vossebeld, J.; Ward, C.P.; Ward, D.R.; Watkins, P.M.; Watson, A.T.; Watson, N.K.; Wells, P.S.; Wengler, T.; Wermes, N.; Wilson, G.W.; Wilson, J.A.; Wolf, G.; Wyatt, T.R.; Yamashita, S.; Zer-Zion, D.; Zivkovic, Lidija

    2006-01-01

    Using the OPAL detector at LEP, the running of the effective QED coupling alpha(t) is measured for space-like momentum transfer through its effect on the angular spectrum of small-angle Bhabha scattering. In an almost ideal QED framework, with very favourable experimental conditions, we obtain: Delta alpha(-6.07GeV^2) - Delta alpha(-1.81GeV^2) = (440 pm 58 pm 43 pm 30) X 10^-5, where the first error is statistical, the second is the experimental systematic and the third is the theoretical uncertainty. This is the strongest direct evidence ever presented that the running of alpha is consistent with Standard Model expectations. The null hypothesis that alpha remains constant within the above interval of -t is excluded with a significance above 5sigma. Similarly, our results are inconsistent at the level of 3sigma with the hypothesis that only leptonic loops contribute to the running, and therefore provide the first clear experimental evidence that hadronic loops also contribute.

  6. 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.

  7. Small-angle neutron-scattering studies of cobalt(II) organophosphorus polymers in deuteriobenzene

    Energy Technology Data Exchange (ETDEWEB)

    Thiyagarajan, P.; Diamond, H.; Danesi, P.R.; Horwitz, E.P.

    1987-12-16

    Bis(2,4,4-trimethylpentyl)phosphinic acid, an extractant used to separate cobalt from nickel by solvent extraction, can form polymers when bound to large amounts of cobalt(II). The size and shape of these polymers have been measured by small-angle neutron scattering. The polymers form long thin chains, approximately 550 A long and about 9 A in radius. In some preparations, although the lengths were similar, the measured average cross-sectional radii were slightly larger, implying some cross-linking. The Co(II) polymers formed from the homologous series phosphoric acid bis(2-ethylhexyl) ester, (2-ethylhexyl)phosphonic acid 2-ethylhexyl ester, and bis(2-ethylhexyl)phosphinic acid were also measured. The first member of this series produced long thin rodlike polymers of constant cross-sectional radius (10 A) and variable lengths; the phosphonic and phosphinic extractants produced smaller polymers whose neutron scattering did not conform to a cylindrical model. 21 references, 5 figures, 6 tables.

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

    Energy Technology Data Exchange (ETDEWEB)

    Franke, Daniel, E-mail: d.franke@embl-hamburg.de [European Molecular Biology Laboratory, Hamburg Outstation Notkestrasse 85, D22603 Hamburg (Germany); Kikhney, Alexey G., E-mail: a.kikhney@embl-hamburg.de [European Molecular Biology Laboratory, Hamburg Outstation Notkestrasse 85, D22603 Hamburg (Germany); Svergun, Dmitri I., E-mail: d.svergun@embl-hamburg.de [European Molecular Biology Laboratory, Hamburg Outstation Notkestrasse 85, D22603 Hamburg (Germany)

    2012-10-11

    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.

  9. Modeling detergent organization around aquaporin-0 using small-angle X-ray scattering.

    Science.gov (United States)

    Berthaud, Alice; Manzi, John; Pérez, Javier; Mangenot, Stéphanie

    2012-06-20

    Solubilization of integral membrane proteins in aqueous solutions requires the presence of amphiphilic molecules like detergents. The transmembrane region of the proteins is then surrounded by a corona formed by these molecules, ensuring a hydrophilic outer surface. The presence of this corona has strongly hampered structural studies of solubilized membrane proteins by small-angle X-ray scattering (SAXS), a technique frequently used to monitor conformational changes of soluble proteins. Through the online combination of size exclusion chromatography, SAXS, and refractometry, we have determined a precise geometrical model of the n-dodecyl β-d-maltopyranoside corona surrounding aquaporin-0, the most abundant membrane protein of the eye lens. The SAXS data were well-fitted by a detergent corona shaped in an elliptical toroid around the crystal structure of the protein, similar to the elliptical shape recently reported for nanodiscs (Skar-Gislinge et al. J. Am. Chem. Soc. 2010, 132, 13713-13722). The torus thickness determined from the curve-fitting protocol is in excellent agreement with the thickness of a lipid bilayer, while the number of detergent molecules deduced from the volume of the torus compares well with those obtained on the same sample from refractometry and mass analysis based on SAXS forward scattering. For the first time, the partial specific volume of the detergent surrounding a protein was measured. The present protocol is a crucial step toward future conformational studies of membrane proteins in solution.

  10. Scattering studies of large scale structures at the ultra small angle neutron scattering instrument S18

    Science.gov (United States)

    Hainbuchner, M.; Baron, M.; Lo Celso, F.; Triolo, A.; Triolo, R.; Rauch, H.

    2002-02-01

    In recent years ultra small angle neutron scattering (USANS) has developed into a powerful standard method for large scale structure investigations. The upgraded instrument S18 at the ILL's 58 MW high flux reactor is operated routinely with increasing beam time demand. The performance of the instrument and its abilities will be discussed in this paper. A peak to background ratio better than 10 5 is reached using Agamalian's tail reduction method. A q-range from 2.10 -5 up to 5.10 -2 Å-1 can be covered. This allows a clear overlap with standard pinhole SANS instruments. The new way collecting scattering data logarithmically equidistant in q-space saves measuring time. This allows measuring times of about 1.5 h for strong scattering specimens with reasonable statistics. We will present an overview of recent experiments which have been performed in co-operation with different groups from the international user community. This work comprises of structure investigations of petroliferous sedimentary rocks showing fractal scattering behaviour and time resolved USANS studies of the dynamics of hydration of cement paste. Concerning soft matter structures, Pirelli rubber nanocomposites have been investigated. In addition, time resolved measurement on a D 2O solution of a PPO-PEO-PPO block copolymer (Reverse Pluronic 25R5) and the dynamics of phase separation of methyl-hydroxy-propyl cellulose (MHPC) have been studied using a sample temperature control system.

  11. Particle-scale structure in frozen colloidal suspensions from small-angle x-ray scattering

    KAUST Repository

    Spannuth, Melissa

    2011-02-01

    During directional solidification of the solvent in a colloidal suspension, the colloidal particles segregate from the growing solid, forming high-particle-density regions with structure on a hierarchy of length scales ranging from that of the particle-scale packing to the large-scale spacing between these regions. Previous work has concentrated mostly on the medium- to large-length scale structure, as it is the most accessible and thought to be more technologically relevant. However, the packing of the colloids at the particle scale is an important component not only in theoretical descriptions of the segregation process, but also to the utility of freeze-cast materials for new applications. Here we present the results of experiments in which we investigated this structure across a wide range of length scales using a combination of small-angle x-ray scattering and direct optical imaging. As expected, during freezing the particles were concentrated into regions between ice dendrites forming a microscopic pattern of high- and low-particle-density regions. X-ray scattering indicates that the particles in the high-density regions were so closely packed as to be touching. However, the arrangement of the particles does not conform to that predicted by standard interparticle pair potentials, suggesting that the particle packing induced by freezing differs from that formed during equilibrium densification processes. © 2011 American Physical Society.

  12. Small-Angle Neutron Scattering and Spontaneous Formation of Unilamellar Vesicles: Potential Vehicles for Drug Delivery

    Science.gov (United States)

    Katsaras, John

    2004-03-01

    Unilamellar vesicles (ULVs) are single-bilayer shells with radii commonly between 10 and 100 nm, and are widely used as model membranes, drug delivery systems, microreactors and substrates for a variety of enzymes and proteins. A common method of making ULVs is the extrusion of multilamellar vesicles (MLVs) through synthetic membranes of known pore size. These extruded ULVs are invariably unstable and in due time, revert back to MLVs. Over the years there have been reports of the spontaneous formation of stable ULVs in surfactant, lipid, and lipid/detergent mixtures. These ULVs have sometimes been shown to be monodisperse and their radii were found, almost without exception, to vary with concentration. We have carried-out small-angle neutron scattering (SANS) experiments on a biomimetic system composed of the phospholipids dimyristoyl and dihexanoyl phosphorylcholine (DMPC and DHPC, respectively). Doping DMPC/DHPC multilamellar vesicles with either the negatively charged lipid dimyristoyl phosphorylglycerol (DMPG, net charge -1) or the divalent cation, calcium (Ca2+) leads to the spontaneous formation of monodisperse unilamellar vesicles whose radii are concentration independent, in contrast to previous experimental observations.

  13. Small-angle X-ray scattering studies of adsorption in Vycor glass.

    Science.gov (United States)

    Mitropoulos, A Ch

    2009-08-15

    Porous Vycor is examined by measuring CH(2)Br(2) adsorption in situ with small-angle X-ray scattering. When a class of pores fills with condensed vapors of this particular adsorbate it ceases to act as scatterer and only the remaining empty pores produce a measurable intensity. By determining a number of scattering curves at various relative pressure loadings details on the structure of the glass as well as on the adsorption/desorption mechanism are obtained. Pore chord length and specific surface area are estimated from Porod tangent analysis to 78 A and 108 m(2)/g. Comparison of the results with those reported for N(2) and Ar adsorption is also given. The role of network effects on the shape of the hysteresis loop is considered and the pore-blocking hypothesis is verified from the scattering spectra. The pore connectivity is calculated to 5.6. The X-ray data are further treated with the inverse Fourier transformation technique. Pore-size distributions are extracted and weighed against the prediction of the Kelvin equation.

  14. Using small-angle neutron scattering to detect nanoscopic lipid domains.

    Science.gov (United States)

    Pan, Jianjun; Heberle, Frederick A; Petruzielo, Robin S; Katsaras, John

    2013-01-01

    The cell plasma membrane is a complex system, which is thought to be capable of exhibiting non-random lateral organization. Studies of live cells and model membranes have yielded mechanisms responsible for the formation, growth, and maintenance of nanoscopic heterogeneities, although the existence and mechanisms that give rise to these heterogeneities remain controversial. Small-angle neutron scattering (SANS) is a tool ideally suited to interrogate lateral heterogeneity in model membranes, primarily due to its unique spatial resolution (i.e., ~5-100nm) and its ability to resolve structure with minimal perturbation to the membrane. In this review we examine several methods used to analyze the SANS signal arising from freely suspended unilamellar vesicles containing lateral heterogeneity. Specifically, we discuss an analytical model for a single, round domain on a spherical vesicle. We then discuss a numerical method that uses Monte Carlo simulation to describe systems with multiple domains and/or more complicated morphologies. Also discussed are several model-independent approaches that are sensitive to membrane heterogeneity. The review concludes with several recent applications of SANS to the study of membrane raft mixtures. Published by Elsevier Ireland Ltd.

  15. Using Small-Angle Neutron Scattering to Detect Nanoscopic Lipid Domains

    Energy Technology Data Exchange (ETDEWEB)

    Pan, Jianjun [ORNL; Heberle, Frederick A [ORNL; Petruzielo, Robin S [Cornell University; Katsaras, John [ORNL

    2013-01-01

    The cell plasma membrane is a complex system, which is thought to be capable of exhibiting non-random lateral organization. Studies of live cells and model membranes have yielded mechanisms responsible for the formation, growth, and maintenance of nanoscopic heterogeneities, although the existence and mechanisms that give rise to these heterogeneities remain controversial. Small-angle neutron scattering (SANS) is a tool ideally suited to interrogate lateral heterogeneity in model membranes, primarily due to its unique spatial resolution (i.e., "5 100 nm) and its ability to resolve structure with minimal perturbation to the membrane. In this review we examine several methods used to analyze the SANS signal arising from freely suspended unilamellar vesicles containing lateral heterogeneity. Specifically, we discuss an analytical model for a single, round domain on a spherical vesicle. We then discuss a numerical method that uses Monte Carlo simulation to describe systems with multiple domains and/or more complicated morphologies. Also discussed are several model-independent approaches that are sensitive to membrane heterogeneity. The review concludes with several recent applications of SANS to the study of membrane raft mixtures.

  16. Joint small-angle X-ray and neutron scattering data analysis of asymmetric lipid vesicles.

    Science.gov (United States)

    Eicher, Barbara; Heberle, Frederick A; Marquardt, Drew; Rechberger, Gerald N; Katsaras, John; Pabst, Georg

    2017-04-01

    Low- and high-resolution models describing the internal transbilayer structure of asymmetric lipid vesicles have been developed. These models can be used for the joint analysis of small-angle neutron and X-ray scattering data. The models describe the underlying scattering length density/electron density profiles either in terms of slabs or through the so-called scattering density profile, previously applied to symmetric lipid vesicles. Both models yield structural details of asymmetric membranes, such as the individual area per lipid, and the hydrocarbon thickness of the inner and outer bilayer leaflets. The scattering density profile model, however, comes at a cost of increased computational effort but results in greater structural resolution, showing a slightly lower packing of lipids in the outer bilayer leaflet of ∼120 nm diameter palmitoyl-oleoyl phosphatidyl-choline (POPC) vesicles, compared to the inner leaflet. Analysis of asymmetric dipalmitoyl phosphatidylcholine/POPC vesicles did not reveal evidence of transbilayer coupling between the inner and outer leaflets at 323 K, i.e. above the melting transition temperature of the two lipids.

  17. Structural Studies of Bleached Melanin by Synchrotron Small-angle X-ray Scattering¶

    Energy Technology Data Exchange (ETDEWEB)

    Littrell, Kenneth C.; Gallas, James M.; Zajac, Gerry W.; Thiyagarajan, Pappannan

    2003-01-01

    Small-angle X-ray scattering was used to measure the effects of chemical bleaching on the size and morphology of tyrosine-derived synthetic melanin dispersed in aqueous media. The average size as measured by the radius of gyration of the melanin particles in solution, at neutral to mildly basic pH, decreases from 16.5 to 12.5 angstroms with increased bleaching. The melanin particles exhibit scattering characteristic of sheet-like structures with a thickness of approximately 11 angstroms at all but the highest levels of bleaching. The scattering data are well described by the form factor for scattering from a pancake-like circular cylinder. These data are consistent with the hypothesis that unbleached melanin, at neutral to mildly basic pH, is a planar aggregate of 6- to 10-nm-sized melanin protomolecules, hydrogen bonded through their quinone and phenolic perimeters. The observed decrease in melanin particle size with increased bleaching is interpreted as evidence for deaggregation, most probably the result of oxidative disruption of hydrogen bonds and an increase in the number of charged, carboxylic acid groups, whereby the melanin aggregates disassociate into units composed of decreasing numbers of protomolecules.

  18. 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.

  19. Counterion Distribution Around Protein-SNAs probed by Small-angle X-ray scattering

    Science.gov (United States)

    Krishnamoorthy, Kurinji; Bedzyk, Michael; Kewalramani, Sumit; Moreau, Liane; Mirkin, Chad

    Protein-DNA conjugates couple the advanced cell transfection capabilities of spherical DNA architecture and the biocompatible enzymatic activity of a protein core to potentially create therapeutic agents with dual functionality. An understanding of their stabilizing ionic environment is crucial to better understand and predict their properties. Here, we use Small-angle X-ray scattering techniques to decipher the structure of the counterion cloud surrounding these DNA coated nanoparticles. Through the use of anomalous scattering techniques we have mapped the local concentrations of Rb+ ions in the region around the Protein-DNA constructs. These results are further corroborated with simulations using a geometric model for the excess charge density as function of radial distance from the protein core. Further, we investigate the influence of solution ionic strength on the structure of the DNA corona and demonstrate a reduction in the extension of the DNA corona with increasing concentration of NaCl in solution for the case of both single and double stranded DNA shells. Our work reveals the distribution of counterions in the vicinity of Protein-DNA conjugates and decouples the effect of solution ionic strength on the thickness of the DNA layer.

  20. Foucault imaging and small-angle electron diffraction in controlled external magnetic fields.

    Science.gov (United States)

    Nakajima, Hiroshi; Kotani, Atsuhiro; Harada, Ken; Ishii, Yui; Mori, Shigeo

    2016-12-01

    We report a method for acquiring Foucault images and small-angle electron diffraction patterns in external magnetic fields using a conventional transmission electron microscope without any modification. In the electron optical system that we have constructed, external magnetic fields parallel to the optical axis can be controlled using the objective lens pole piece under weak excitation conditions in the Foucault mode and the diffraction mode. We observe two ferromagnetic perovskite-type manganese oxides, La 0.7 Sr 0.3 MnO 3 (LSMO) and Nd 0.5 Sr 0.5 MnO 3 , in order to visualize magnetic domains and their magnetic responses to external magnetic fields. In rhombohedral-structured LSMO, pinning of magnetic domain walls at crystallographic twin boundaries was found to have a strong influence on the generation of new magnetic domains in external applied magnetic fields. © The Author 2016. Published by Oxford University Press on behalf of The Japanese Society of Microscopy. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  1. OPTICAL MICROSCOPY AND SMALL-ANGLE SCATTERING STUDY OF POROSITY IN THERMALLY TREATED PBX 9501

    Energy Technology Data Exchange (ETDEWEB)

    Mang, J. T. (Joseph T.); Skidmore, C. B. (Cary B.); Hjelm, R. P. (Rex P.); Ricker, T. P. (Thomas P.); Son, S. F. (Steven F.)

    2001-01-01

    Heat transfer and comlmstion properties of a high explosive (HE) are influenced by the HE microstructure. The development of voids and cracks in an HE system under the conditions of thermal loading can have a strong impact on the safety and reliability of a weapon system. The optical microscopy and small angle x-ray scattering (SAXS) techniques are useful tools for microstructural characterization. A combination of the tools allows lengthscales from hundreds of microns to tenths of nanometers to be probed, allowing a thorough description of a system's microstructure to be made. We present an optical microscopy and SAXS study of the effects of thermal loading on the microstructure of PBX 9501. Pressed pellets of PBX 9501, an HMX-based system, were heated in an oven at 180 'C for periods of 0, 15 and 30 minutes. Optical micrographs reveal the developmenit of large pores in the microstructure with increasing thermal treatment as well as increased cracking and morphological changes of crystal grains, associated with the beta to delta phase transition in HMX. SAXS measurements were performed in order to quantify the observed porosity,

  2. 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

  3. A new small-angle neutron scattering spectrometer at China Mianyang research reactor

    Energy Technology Data Exchange (ETDEWEB)

    Peng, Mei, E-mail: pm740509@163.com; Sun, Liangwei; Chen, Liang; Sun, Guangai; Chen, Bo; Xie, Chaomei; Xia, Qingzhong; Yan, Guanyun; Tian, Qiang; Huang, Chaoqiang; Pang, Beibei; Zhang, Ying; Wang, Yun; Liu, Yaoguang; Kang, Wu; Gong, Jian

    2016-02-21

    A new pinhole small-angle neutron scattering (SANS) spectrometer, installed at the cold neutron source of the 20 MW China Mianyang Research Reactor (CMRR) in the Institute of Nuclear Physics and Chemistry, China Academy of Engineering Physics, has been put into use since 2014. The spectrometer is equipped with a multi-blade mechanical velocity selector, a multi-beam collimation system, and a two-dimensional He-3 position sensitive neutron detector. The q-range of the spectrometer covers from 0.01 nm{sup −1} to 5.0 nm{sup −1}. In this paper, the design and characteristics of the SANS spectrometer are described. The q-resolution calculations, together with calibration measurements of silver behenate and a dispersion of nearly monodisperse poly-methyl-methacrylate nanoparticles indicate that our SANS spectrometer has a good performance and is now in routine service. - Highlights: • A new SANS spectrometer has been put into use since 2014 in China. • One MBR selector possesses a higher resolution compared with traditional selector is used. • The spectrometer has a good performance and is now in routinely service.

  4. 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...

  5. Measurement of small-angle antiproton-proton and proton-proton elastic scattering at the CERN intersecting storage rings

    NARCIS (Netherlands)

    Amos, N.; Block, M.M.; Bobbink, G.J.; Botje, M.A.J.; Favart, D.; Leroy, C.; Linde, F.; Lipnik, P.; Matheys, J-P.; Miller, D.

    1985-01-01

    Antiproton-proton and proton-proton small-angle elastic scattering was measured for centre-of-mass energies at the CERN Intersectung Storage Rings. In addition, proton-proton elastic scattering was measured at . Using the optical theorem, total cross sections are obtained with an accuracy of about

  6. Small Angle Shubnikov-de Haas Measurements in Silicon MOSFET's : The Effect of Strong In-Plane Magnetic Field

    NARCIS (Netherlands)

    Vitkalov, S.A.; Zheng, H.; Sarachik, M.P.; Klapwijk, T.M.

    2000-01-01

    Measurements in magnetic fields applied at small angles relative to the electron plane in silicon MOSFETs indicate a factor of two increase of the frequency of Shubnikov-de Haas oscillations at H>H_{sat}. This signals the onset of full spin polarization above H_{sat}, the parallel field above which

  7. 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.

  8. Small-angle X-ray scattering: a high-throughput technique for investigating archaeological bone preservation

    NARCIS (Netherlands)

    Hiller, J.C.; Collins, M.J.; Chamberlain, A.T.; Wess, T.J.

    2004-01-01

    Diagenetic alteration to archaeological bone can cause significant disruption to both the biogenic mineral structure and the preservation of biomolecular resources such as protein and DNA over archaeological time. We report here the use of a technique, small-angle X-ray scattering, which makes it

  9. Low-temperature dynamics of magnetic colloids studied by time-resolved small-angle neutron scattering

    NARCIS (Netherlands)

    Wiedenmann, A.; Keiderling, U.; Meissner, M.; Wallacher, D.; Gähler, R.; May, R.P.; Prévost, S.; Klokkenburg, M.; Erne, B.H.; Kohlbrecher, J.

    2008-01-01

    The dynamics of ordering and relaxation processes in magnetic colloids has been studied by means of stroboscopic small angle neutron scattering techniques in an oscillating magnetic field. Surfactant stabilized ferrofluids (FFs) of Fe3O4 and Co nanoparticles have been investigated as a function of

  10. Dipolar structures in magnetite ferrofluids studied with small-angle neutron scattering with and without applied magnetic field

    NARCIS (Netherlands)

    Klokkenburg, M.; Erne, B.H.; Wiedenmann, A.; Petukhov, A.V.; Philipse, A.P.

    2007-01-01

    Field-induced structure formation in a ferrofluid with well-defined magnetite nanoparticles with a permanent magnetic dipole moment was studied with small-angle neutron scattering (SANS) as a function of the magnetic interactions. The interactions were tuned by adjusting the size of the

  11. Nanoscale uniformity of pore architecture in diatomaceous silica : A combined small and wide angle X-ray scattering study

    NARCIS (Netherlands)

    Vrieling, EG; Beelen, TPM; van Santen, RA; Gieskes, WWC

    Combined small and wide angle IZ-ray scattering (SAXS and WAXS) analysis was applied to purified biogenic silica of cultured diatom frustules and of natural populations sampled on marine tidal flats. The overall WAXS patterns did not reveal crystalline phases (WAXS domain between 0.07 to 0.5 nm) in

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

    Science.gov (United States)

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

    2008-10-01

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

    De Felici, M; Felici, R; Ferrero, C [European Synchrotron Radiation Facility, BP 220, 38043 Grenoble Cedex 9 (France); Tartari, A; Gambaccini, M [Physics Department, University of Ferrara, 44100 Ferrara (Italy); Finet, S [Universite Pierre et Marie Curie, BP29, 75252 Paris Cedex 05 (France)

    2008-10-21

    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.

  14. Colloidal structure and stability of DNA/polycations polyplexes investigated by small angle scattering.

    Science.gov (United States)

    Prévost, Sylvain; Riemer, Sven; Fischer, Wiebke; Haag, Rainer; Böttcher, Christoph; Gummel, Jérémie; Grillo, Isabelle; Appavou, Marie-Sousai; Gradzielski, Michael

    2011-12-12

    Polyplexes of short DNA-fragments (300 b.p., 100 nm) with tailor-made amine-based polycations of different architectures (linear and hyperbranched) were investigated in buffer solution as a function of the mixing ratio with DNA. The resulting dispersed polyplexes were characterized using small-angle neutron and X-ray scattering (SANS, SAXS) as well as cryo-TEM with respect to their mesoscopic structure and their colloidal stability. The linear polyimines form rather compact structures that have a high tendency for precipitation. In contrast, the hyperbranched polycation with enzymatic-labile pentaethylenehexamine arms (PEHA) yields polyplexes colloidally stable for months. Here the polycation coating of DNA results in a homogeneous dispersion based on a fractal network with low structural organization at low polycation amount. With increasing polycation, bundles of tens of aligned DNA rods appear that are interconnected in a fractal network with a typical correlation distance on the order of 100 nm, the average length of the DNA used. With higher organization comes a decrease in stability. The 3D network built by these beams can still exhibit some stability as long as the material concentration is large enough, but the structure collapses upon dilution. SAXS shows that the complexation does not affect the local DNA structure. Interestingly, the structural findings on the DNA polyplexes apparently correlate with the transfection efficiency of corresponding siRNA complexes. In general, these finding not only show systematic trends for the colloid stability, but may allow for rational approaches to design effective transfection carriers.

  15. Branch Point Withdrawal in Elongational Startup Flow by Time-Resolved Small Angle Neutron Scattering

    KAUST Repository

    Ruocco, N.

    2016-05-27

    We present a small angle neutron scattering (SANS) investigation of a blend composed of a dendritic polymer and a linear matrix with comparable viscosity in start-up of an elongational flow at Tg + 50. The two-generation dendritic polymer is diluted to 10% by weight in a matrix of a long well-entangled linear chains. Both components consist of mainly 1,4-cis-polyisoprene but differ in isotopic composition. The resulting scattering contrast is sufficiently high to permit time-resolved measurements of the system structure factor during the start-up phase and to follow the retraction processes involving the inner sections of the branched polymer in the nonlinear deformation response. The outer branches and the linear matrix, on the contrary, are in the linear deformation regime. The linear matrix dominates the rheological signature of the blend and the influence of the branched component can barely be detected. However, the neutron scattering intensity is predominantly that of the (branched) minority component so that its dynamics is clearly evident. In the present paper, we use the neutron scattering data to validate the branch point withdrawal process, which could not be unambiguously discerned from rheological measurements in this blend. The maximal tube stretch that the inner branches experience, before the relaxed outer arm material is incorporated into the tube is determined. The in situ scattering experiments demonstrate for the first time the leveling-off of the strain as the result of branch point withdrawal and chain retraction directly on the molecular level. We conclude that branch point motion in the mixture of architecturally complex polymers occurs earlier than would be expected in a purely branched system, presumably due to the different topological environment that the linear matrix presents to the hierarchically deep-buried tube sections. © 2016 American Chemical Society.

  16. Monitoring thylakoid ultrastructural changes in vivo using small-angle neutron scattering.

    Science.gov (United States)

    Unnep, Renáta; Nagy, Gergely; Markó, Márton; Garab, Győző

    2014-08-01

    The light reactions of oxygenic photosynthesis take place in the thylakoid membranes, flattened vesicles, which contain the two photosystems and also embed the cytochrome b6f complex and the ATP synthase. In general, the thylakoid membranes are assembled into multilamellar membrane systems, which warrant an optimal light capturing efficiency. In nature, they show astounding variations, primarily due to large variations in their protein composition, which is controlled by multilevel regulatory mechanisms during long-term acclimation and short-term adaptation processes and also influenced by biotic or abiotic stresses - indicating a substantial degree of flexibility in the membrane ultrastructure. The better understanding of the dynamic features of this membrane system requires the use of non-invasive techniques, such as small angle neutron scattering (SANS), which is capable of providing accurate, statistically and spatially averaged information on the repeat distances of periodically organized thylakoid membranes under physiologically relevant conditions with time resolutions of seconds and minutes. In this review, after a short section on the basic properties of neutrons, we outline the fundamental principles of SANS measurements, its strengths and weaknesses in comparison to complementary structure investigation techniques. Then we overview recent results on isolated plant thylakoid membranes, and on living cyanobacterial and algal cells as well as on whole leaves. Special attention is paid to light-induced reversible ultrastructural changes in vivo, which, in cyanobacterial and diatom cells, were uncovered with the aid of SANS measurements; we also discuss the role of membrane reorganizations in light adaptation and photoprotection mechanisms. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

  17. The dynamic duo: combining NMR and small angle scattering in structural biology.

    Science.gov (United States)

    Hennig, Janosch; Sattler, Michael

    2014-06-01

    Structural biology provides essential information for elucidating molecular mechanisms that underlie biological function. Advances in hardware, sample preparation, experimental methods, and computational approaches now enable structural analysis of protein complexes with increasing complexity that more closely represent biologically entities in the cellular environment. Integrated multidisciplinary approaches are required to overcome limitations of individual methods and take advantage of complementary aspects provided by different structural biology techniques. Although X-ray crystallography remains the method of choice for structural analysis of large complexes, crystallization of flexible systems is often difficult and does typically not provide insights into conformational dynamics present in solution. Nuclear magnetic resonance spectroscopy (NMR) is well-suited to study dynamics at picosecond to second time scales, and to map binding interfaces even of large systems at residue resolution but suffers from poor sensitivity with increasing molecular weight. Small angle scattering (SAS) methods provide low resolution information in solution and can characterize dynamics and conformational equilibria complementary to crystallography and NMR. The combination of NMR, crystallography, and SAS is, thus, very useful for analysis of the structure and conformational dynamics of (large) protein complexes in solution. In high molecular weight systems, where NMR data are often sparse, SAS provides additional structural information and can differentiate between NMR-derived models. Scattering data can also validate the solution conformation of a crystal structure and indicate the presence of conformational equilibria. Here, we review current state-of-the-art approaches for combining NMR, crystallography, and SAS data to characterize protein complexes in solution. © 2014 The Protein Society.

  18. Characterisation of nanovoiding in dental porcelain using small angle neutron scattering and transmission electron microscopy.

    Science.gov (United States)

    Lunt, Alexander; Terry, Ann; Ying, Siqi; Baimpas, Nikolaos; Sui, Tan; Kabra, Saurabh; Kelleher, Joe; King, Stephen; Khin, Neo Tee; Korsunsky, Alexander M

    2017-05-01

    Recent studies of the yttria partially stabilised zirconia-porcelain interface have revealed the presence of near-interface porcelain nanovoiding which reduces toughness and leads to component failure. One potential explanation for these nanoscale features is thermal creep which is induced by the combination of the residual stresses at the interface and sintering temperatures applied during manufacture. The present study provides improved understanding of this important phenomenon. Transmission electron microscopy and small angle neutron scattering were applied to a sample which was crept at 750°C and 100MPa (sample C), a second which was exposed to an identical heat treatment schedule in the absence of applied stress (sample H), and a reference sample in the as-machined state (sample A). The complementary insights provided by the two techniques were in good agreement and log-normal void size distributions were found in all samples. The void number density was found to be 1.61μm-2, 25.4μm-2 and 98.6μm-2 in samples A, H and C respectively. The average void diameter in sample A (27.1nm) was found to be more than twice as large as in samples H (10.2nm) and C (11.6nm). The crept data showed the highest skewness parameter (2.35), indicating stress-induced growth of larger voids and void coalescence that has not been previously observed. The improved insight presented in this study can be integrated into existing models of dental prostheses in order to optimise manufacturing routes and thereby reduce the significant detrimental impact of this nanostructural phenomenon. Copyright © 2017 The Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

  19. Morphology of fast-tumbling bicelles: a small angle neutron scattering and NMR study.

    Science.gov (United States)

    Luchette, P A; Vetman, T N; Prosser, R S; Hancock, R E; Nieh, M P; Glinka, C J; Krueger, S; Katsaras, J

    2001-08-06

    Bilayered micelles, or bicelles, which consist of a mixture of long- and short-chain phospholipids, are a popular model membrane system. Depending on composition, concentration, and temperature, bicelle mixtures may adopt an isotropic phase or form an aligned phase in magnetic fields. Well-resolved (1)H NMR spectra are observed in the isotropic or so-called fast-tumbling bicelle phase, over the range of temperatures investigated (10-40 degrees C), for molar ratios of long-chain lipid to short-chain lipid between 0.20 and 1.0. Small angle neutron scattering data of this phase are consistent with the model in which bicelles were proposed to be disk-shaped. The experimentally determined dimensions are roughly consistent with the predictions of R.R. Vold and R.S. Prosser (J. Magn. Reson. B 113 (1996)). Differential paramagnetic shifts of head group resonances of dimyristoylphosphatidylcholine (DMPC) and dihexanoylphosphatidylcholine (DHPC), induced by the addition of Eu(3+), are also consistent with the bicelle model in which DHPC is believed to be primarily sequestered to bicelle rims. Selective irradiation of the DHPC aliphatic methyl resonances results in no detectable magnetization transfer to the corresponding DMPC methyl resonances (and vice versa) in bicelles, which also suggests that DHPC and DMPC are largely sequestered in the bicelle. Finally, (1)H spectra of the antibacterial peptide indolicidin (ILPWKWPWWPWRR-NH(2)) are compared, in a DPC micellar phase and the above fast-tumbling bicellar phases for a variety of compositions. The spectra exhibit adequate resolution and improved dispersion of amide and aromatic resonances in certain bicelle mixtures.

  20. Size And Shape of Detergent Micelles Determined By Small-Angle X-Ray Scattering

    Energy Technology Data Exchange (ETDEWEB)

    Lipfert, Jan; Columbus, Linda; Chu, Vincent B.; Lesley, Scott A.; Doniach, Sebastian; /Stanford U., Phys. Dept. /Stanford U., Appl. Phys. Dept. /SLAC, SSRL /Pasteur Inst., Paris /Scripps Res. Inst. /Novartis Res. Found.

    2009-04-29

    We present a systematic analysis of the aggregation number and shape of micelles formed by nine detergents commonly used in the study of membrane proteins. Small-angle X-ray scattering measurements are reported for glucosides with 8 and 9 alkyl carbons (OG/NG), maltosides and phosphocholines with 10 and 12 alkyl carbons (DM/DDM and FC-10/FC-12), 1,2-dihexanoyl-sn-glycero-phosphocholine (DHPC), 1-palmitoyl-2-hydroxy-sn-glycero-3-[phospho-rac-(1-glycerol)] (LPPG), and 3-[(3-cholamidopropyl)dimethylammonio]-1-propane sulfonate (CHAPS). The SAXS intensities are well described by two-component ellipsoid models, with a dense outer shell corresponding to the detergent head groups and a less electron dense hydrophobic core. These models provide an intermediate resolution view of micelle size and shape. In addition, we show that Guinier analysis of the forward scattering intensity can be used to obtain an independent and model-free measurement of the micelle aggregation number and radius of gyration. This approach has the advantage of being easily generalizable to protein-detergent complexes, where simple geometric models are inapplicable. Furthermore, we have discovered that the position of the second maximum in the scattering intensity provides a direct measurement of the characteristic head group-head group spacing across the micelle core. Our results for the micellar aggregation numbers and dimensions agree favorably with literature values as far as they are available. We de novo determine the shape of FC-10, FC-12, DM, LPPG, and CHAPS micelles and the aggregation numbers of FC-10 and OG to be ca. 50 and 250, respectively. Combined, these data provide a comprehensive view of the determinants of micelle formation and serve as a starting point to correlate detergent properties with detergent-protein interactions.

  1. Calculation of accurate small angle X-ray scattering curves from coarse-grained protein models

    Directory of Open Access Journals (Sweden)

    Stovgaard Kasper

    2010-08-01

    Full Text Available Abstract Background Genome sequencing projects have expanded the gap between the amount of known protein sequences and structures. The limitations of current high resolution structure determination methods make it unlikely that this gap will disappear in the near future. Small angle X-ray scattering (SAXS is an established low resolution method for routinely determining the structure of proteins in solution. The purpose of this study is to develop a method for the efficient calculation of accurate SAXS curves from coarse-grained protein models. Such a method can for example be used to construct a likelihood function, which is paramount for structure determination based on statistical inference. Results We present a method for the efficient calculation of accurate SAXS curves based on the Debye formula and a set of scattering form factors for dummy atom representations of amino acids. Such a method avoids the computationally costly iteration over all atoms. We estimated the form factors using generated data from a set of high quality protein structures. No ad hoc scaling or correction factors are applied in the calculation of the curves. Two coarse-grained representations of protein structure were investigated; two scattering bodies per amino acid led to significantly better results than a single scattering body. Conclusion We show that the obtained point estimates allow the calculation of accurate SAXS curves from coarse-grained protein models. The resulting curves are on par with the current state-of-the-art program CRYSOL, which requires full atomic detail. Our method was also comparable to CRYSOL in recognizing native structures among native-like decoys. As a proof-of-concept, we combined the coarse-grained Debye calculation with a previously described probabilistic model of protein structure, TorusDBN. This resulted in a significant improvement in the decoy recognition performance. In conclusion, the presented method shows great promise for

  2. Application of advanced shearing techniques to the calibration of autocollimators with small angle generators and investigation of error sources.

    Science.gov (United States)

    Yandayan, T; Geckeler, R D; Aksulu, M; Akgoz, S A; Ozgur, B

    2016-05-01

    The application of advanced error-separating shearing techniques to the precise calibration of autocollimators with Small Angle Generators (SAGs) was carried out for the first time. The experimental realization was achieved using the High Precision Small Angle Generator (HPSAG) of TUBITAK UME under classical dimensional metrology laboratory environmental conditions. The standard uncertainty value of 5 mas (24.2 nrad) reached by classical calibration method was improved to the level of 1.38 mas (6.7 nrad). Shearing techniques, which offer a unique opportunity to separate the errors of devices without recourse to any external standard, were first adapted by Physikalisch-Technische Bundesanstalt (PTB) to the calibration of autocollimators with angle encoders. It has been demonstrated experimentally in a clean room environment using the primary angle standard of PTB (WMT 220). The application of the technique to a different type of angle measurement system extends the range of the shearing technique further and reveals other advantages. For example, the angular scales of the SAGs are based on linear measurement systems (e.g., capacitive nanosensors for the HPSAG). Therefore, SAGs show different systematic errors when compared to angle encoders. In addition to the error-separation of HPSAG and the autocollimator, detailed investigations on error sources were carried out. Apart from determination of the systematic errors of the capacitive sensor used in the HPSAG, it was also demonstrated that the shearing method enables the unique opportunity to characterize other error sources such as errors due to temperature drift in long term measurements. This proves that the shearing technique is a very powerful method for investigating angle measuring systems, for their improvement, and for specifying precautions to be taken during the measurements.

  3. Small-angle neutron scattering study of sodium cholate and sodium ...

    Indian Academy of Sciences (India)

    angle neutron scattering study of sodium cholate and sodium deoxycholate interacting micelles in aqueous medium. J Santhanalakshmi G Shantha Lakshmi V K Aswal P S Goyal. Physical and Theoretical Volume 113 Issue 1 February 2001 pp 55- ...

  4. Tunable moire bands and strong correlations in small-twist-angle bilayer graphene

    National Research Council Canada - National Science Library

    Kim, Kyounghwan; DaSilva, Ashley; Huang, Shengqiang; Fallahazad, Babak; Larentis, Stefano; Taniguchi, Takashi; Watanabe, Kenji; LeRoy, Brian J; MacDonald, Allan H; Tutuc, Emanuel

    2017-01-01

    ... between its individual layer honeycomb lattices. We have realized bilayer graphene moire crystals with accurately controlled twist angles smaller than 1 degree and studied their properties using scanning probe microscopy and electron transport...

  5. Monte Carlo, small angle light scattering, and dynamic light scattering studies of dilute polymer solutions

    Science.gov (United States)

    McNamara, Joseph E.

    The adsorption of negatively charged polymer, negative/neutral block copolymer and a polyampholyte to patterned surfaces is investigated using off-lattice Monte Carlo simulations. The surface is decorated by stripe and checkerboard patterns of mixed charges. The polymer has periodic charge segments, which potentially match the periodicity of the surface pattern. Results show that the chain entropy of a flexible polymer disrupts and prevents full pattern recognition. Quantities such as average adsorption energy and the radii of gyration of the adsorbed polymer are calculated and found to be dictated by the size of the surface pattern and its correlation to the polymer charge density. We performed small angle light scattering on dilute-solution-grown polyethylene crystals grown from quenches in para-xylene. The quench depths ranged from 60 to 85°C for 0.05 wt.% and 0.1 wt.% linear-low-polydispersity polyethylenes. We found asymmetric scattering patterns for the lower temperature quenches to 65°C, and symmetric scattering patterns for the higher temperature quenches to 80°C. There is a smooth transition from asymmetric to symmetric scattering as we change the quench depth. The correlation lengths d=2pi/qmax corresponding to the peaks of intensity versus q ranged from 15 to 30 mum. We find evidence that these length scales correspond to assemblies of single polyethylene crystals. Also, we have performed dynamic light scattering on solutions of sodium-poly(styrene-sulfonate) (NaPSS) and poly(ethylene-oxide) (PEO) in water with BaCl2. The fast mode ( Dfast) and slow mode (Dslow) diffusion coefficients were measured as a function of polymer concentration for both polymers in dilute solution. We found that the diffusion coefficients remained relatively constant in the concentration regimes investigated and Dfast and Dslow for both polymers differed by about 1½ orders of magnitude: 1.1 x 10-6 cm2/s versus 7.8 x 10-8 cm2/s for NaPSS and 6.7 x 10-7 cm2/s versus 4.2 x 10

  6. Small angle neutron scattering studies of the flux line lattices in the borocarbide superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Eskildsen, Morten Ring

    1998-12-01

    This thesis describes small angle neutron scattering studies of the flux line lattice (FLL) in the following members of the borocarbide superconductors: YNi{sub 2}B{sub 2}C, ErNi{sub 2}B{sub 2}C, TmNi{sub 2}B{sub 2}C, LuNi{sub 2}B{sub 2}C, Y{sub 0.75}Lu{sub 0.25}Ni{sub 2}B{sub 2}C and Lu(Ni{sub 1-x}CO{sub x}){sub 2}B{sub 2}C with x = 1.5 - 9%. Of the materials ErN{sub 2}B{sub 2}C and TmNi{sub 2}B{sub 2}C exhibits coexisting superconductivity and magnetic ordering. Three main conclusions can be derived from the results in this thesis. Existence of a low field hexagonal to square symmetry transition of the FLL, ubiquitous to the superconducting borocarbides, magnetic and non-magnetic alike. This symmetry transition is due to the four-fold anisotropy of the Fermi surface, distorting the screening currents towards a square flow pattern. This four-fold anisotropy together with non-local electrodynamics induces a transition to a square FLL, as the field is increased. Changing the non-locality range shifts the square to hexagonal transition onset field. A static disordering of the FLL in YNi{sub 2}B{sub 2}C and LuNi{sub 2}B{sub 2}C. In these materials one observes a well ordered FLL, with a longitudinal correlation length exceeding 100 flux line spacings. As the applied field is increased the longitudinal correlation length, increases with field up to H/H{sub c2} {approx} 0.2. Above this field the FLL correlation length slowly starts to fall off, in contradiction to theoretical models. The existence of complex interactions between the magnetic state and the FLL in TmNi{sub 2}B{sub 2}C. This is signalled by coinciding changes in the FLL symmetry and in the magnetic structure. The FLL show a two-step symmetry transition from square to rhombic and then hexagonal with increased field. In addition, the FLL reflectivity shows distinct peaks as the thulium ions orders magnetically at T{sub N} and across the field driven magnetic transition. No explanation for this behaviour

  7. Initial characterization of mudstone nanoporosity with small angle neutron scattering using caprocks from carbon sequestration sites.

    Energy Technology Data Exchange (ETDEWEB)

    McCray, John (Colorado School of Mines); Navarre-Sitchler, Alexis (Colorado School of Mines); Mouzakis, Katherine (Colorado School of Mines); Heath, Jason E.; Dewers, Thomas A.; Rother, Gernot (Oak Ridge National Laboratory)

    2010-11-01

    Geological carbon sequestration relies on the principle that CO{sub 2} injected deep into the subsurface is unable to leak to the atmosphere. Structural trapping by a relatively impermeable caprock (often mudstone such as a shale) is the main trapping mechanism that is currently relied on for the first hundreds of years. Many of the pores of the caprock are of micrometer to nanometer scale. However, the distribution, geometry and volume of porosity at these scales are poorly characterized. Differences in pore shape and size can cause variation in capillary properties and fluid transport resulting in fluid pathways with different capillary entry pressures in the same sample. Prediction of pore network properties for distinct geologic environments would result in significant advancement in our ability to model subsurface fluid flow. Specifically, prediction of fluid flow through caprocks of geologic CO{sub 2} sequestration reservoirs is a critical step in evaluating the risk of leakage to overlying aquifers. The micro- and nanoporosity was analyzed in four mudstones using small angle neutron scattering (SANS). These mudstones are caprocks of formations that are currently under study or being used for carbon sequestration projects and include the Marine Tuscaloosa Group, the Lower Tuscaloosa Group, the upper and lower shale members of the Kirtland Formation, and the Pennsylvanian Gothic shale. Total organic carbon varies from <0.3% to 4% by weight. Expandable clay contents range from 10% to {approx}40% in the Gothic shale and Kirtland Formation, respectively. Neutrons effectively scatter from interfaces between materials with differing scattering length density (i.e. minerals and pores). The intensity of scattered neutrons, I(Q), where Q is the scattering vector, gives information about the volume of pores and their arrangement in the sample. The slope of the scattering data when plotted as log I(Q) vs. log Q provides information about the fractality or geometry of

  8. 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

  9. Small angle X-ray scattering and transmission electron microscopy study of the Lactobacillus brevis S-layer protein

    Science.gov (United States)

    Jääskeläinen, Pentti; Engelhardt, Peter; Hynönen, Ulla; Torkkeli, Mika; Palva, Airi; Serimaa, Ritva

    2010-10-01

    The structure of self-assembly domain containing recombinant truncation mutants of Lactobacillus brevis surface layer protein SlpA in aqueous solution was studied using small-angle X-ray scattering and transmission electron microscopy. The proteins were found out to interact with each other forming stable globular oligomers of about 10 monomers. The maximum diameter of the oligomers varied between 75 Å and 435 Å.

  10. 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.

  11. Relationship between the atomic pair distribution function and small-angle scattering: implications for modeling of nanoparticles.

    Science.gov (United States)

    Farrow, Christopher L; Billinge, Simon J L

    2009-05-01

    The relationship between the equations used in the atomic pair distribution function (PDF) method and those commonly used in small-angle-scattering (SAS) analyses is explicitly shown. The origin of the sloping baseline, -4pirrho0, in PDFs of bulk materials is identified as originating from the SAS intensity that is neglected in PDF measurements. The nonlinear baseline in nanoparticles has the same origin, and contains information about the shape and size of the nanoparticles.

  12. Monte-Carlo simulation of an ultra small-angle neutron scattering instrument based on Soller slits

    Energy Technology Data Exchange (ETDEWEB)

    Rieker, T. [Univ. of New Mexico, Albuquerque, NM (United States); Hubbard, P. [Sandia National Labs., Albuquerque, NM (United States)

    1997-09-01

    Monte Carlo simulations are used to investigate an ultra small-angle neutron scattering instrument for use at a pulsed source based on a Soller slit collimator and analyzer. The simulations show that for a q{sub min} of {approximately}le-4 {angstrom}{sup -1} (15 {angstrom} neutrons) a few tenths of a percent of the incident flux is transmitted through both collimators at q=0.

  13. 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

  14. Small angle X-ray scattering and transmission electron microscopy study of the Lactobacillus brevis S-layer protein

    Energy Technology Data Exchange (ETDEWEB)

    Jaeaeskelaeinen, Pentti [Department of Biomedical Engineering and Computational Science, PO Box 2200, FI-02015 Aalto University School of Science and Technology (Finland); Engelhardt, Peter [Haartman Institute, Department of Pathology, PO Box 21, FIN-00014 University of Helsinki (Finland); Hynoenen, Ulla; Palva, Airi [Department of Basic Veterinary Sciences, Division of Microbiology, FIN-00014 University of Helsinki (Finland); Torkkeli, Mika; Serimaa, Ritva, E-mail: ritva.serimaa@helsinki.f [Department of Physics, POB 64, 00014 University of Helsinki (Finland)

    2010-10-01

    The structure of self-assembly domain containing recombinant truncation mutants of Lactobacillus brevis surface layer protein SlpA in aqueous solution was studied using small-angle X-ray scattering and transmission electron microscopy. The proteins were found out to interact with each other forming stable globular oligomers of about 10 monomers. The maximum diameter of the oligomers varied between 75 A and 435 A.

  15. Thermal degradation of M41S-class mesoporous sieves as revealed by small angle X-ray scattering

    Energy Technology Data Exchange (ETDEWEB)

    Hunt, J. E.; Xu, L.; Winans, R. E.; Seifert, S.

    2000-02-16

    The authors have studied the temperature stability of M41S class siliceous mesoporous materials loaded with carbonaceous material by temperature programmed small-angle X-ray scattering (TPSAXS) techniques. Results show the thermal structural instability of large pore pure silica sieve material with carbonaceous material (such as coal extracts) occluded within the pores of mesoporous 31 {angstrom} M41S materials. Unfilled pore M41S materials do not show thermal-related structural instability.

  16. Jointed magnetic skyrmion lattices at a small-angle grain boundary directly visualized by advanced electron microscopy.

    Science.gov (United States)

    Matsumoto, Takao; So, Yeong-Gi; Kohno, Yuji; Sawada, Hidetaka; Ishikawa, Ryo; Ikuhara, Yuichi; Shibata, Naoya

    2016-10-24

    The interactions between magnetic skyrmions and structural defects, such as edges, dislocations, and grain boundaries (GBs), which are all considered as topological defects, will be important issues when magnetic skyrmions are utilized for future memory device applications. To investigate such interactions, simultaneous visualization of magnetic skyrmions and structural defects at high spatial resolution, which is not feasible by conventional techniques, is essential. Here, taking advantages of aberration-corrected differential phase-contrast scanning transmission electron microscopy, we investigate the interaction of magnetic skyrmions with a small-angle GB in a thin film of FeGe 1-x Si x . We found that the magnetic skyrmions and the small-angle GB can coexist each other, but a domain boundary (DB) was formed in the skyrmion lattice along the small-angle GB. At the core of the DB, unexpectedly deformed magnetic skrymions, which appear to be created by joining two portions of magnetic skyrmions in the adjacent lattices, were formed to effectively compensate misorientations between the two adjacent magnetic skyrmion lattices. These observations strongly suggest the flexible nature of individual magnetic skyrmions, and also the significance of defect engineering for future device applications.

  17. Effects of small-angle mistilts on dopant visibility in ADF-STEM imaging of nanocrystals.

    Science.gov (United States)

    Held, Jacob T; Duncan, Samuel; Mkhoyan, K Andre

    2017-06-01

    Quantitative ADF-STEM imaging paired with image simulations has proven to be a powerful technique for determining the three dimensional location of substitutionally doped atoms in thin films. Expansion of this technique to lightly-doped nanocrystals requires an understanding of the influence of specimen mistilt on dopant visibility due to the difficulty of accurate orientation determination in such systems as well as crystal movement under the beam. In this study, the effects of specimen mistilt on ADF-STEM imaging are evaluated using germanium-doped silicon nanocrystals as model systems. It is shown that dopant visibility is a strong function of specimen mistilt, and the accuracy of specimen orientation is an important factor in the analysis of three-dimensional dopant location, but the sensitivity to mistilt can be weakened by increasing the STEM probe convergence angle and optimizing ADF detector inner angle. Copyright © 2017 Elsevier B.V. All rights reserved.

  18. Quantitative impact of small angle forward scatter on whole blood oximetry using a Beer-Lambert absorbance model.

    Science.gov (United States)

    LeBlanc, Serge Emile; Atanya, Monica; Burns, Kevin; Munger, Rejean

    2011-04-21

    It is well known that red blood cell scattering has an impact on whole blood oximetry as well as in vivo retinal oxygen saturation measurements. The goal of this study was to quantify the impact of small angle forward scatter on whole blood oximetry for scattering angles found in retinal oximetry light paths. Transmittance spectra of whole blood were measured in two different experimental setups: one that included small angle scatter in the transmitted signal and one that measured the transmitted signal only, at absorbance path lengths of 25, 50, 100, 250 and 500 µm. Oxygen saturation was determined by multiple linear regression in the 520-600 nm wavelength range and compared between path lengths and experimental setups. Mean calculated oxygen saturation differences between setups were greater than 10% at every absorbance path length. The deviations to the Beer-Lambert absorbance model had different spectral dependences between experimental setups, with the highest deviations found in the 520-540 nm range when scatter was added to the transmitted signal. These results are consistent with other models of forward scatter that predict different spectral dependences of the red blood cell scattering cross-section and haemoglobin extinction coefficients in this wavelength range.

  19. 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.

  20. Small angle scattering polarization biopsy: a comparative analysis of various skin diseases

    Science.gov (United States)

    Zimnyakov, D. A.; Alonova, M. V.; Yermolenko, S. B.; Ivashko, P. V.; Reshetnikova, E. M.; Galkina, E. M.; Utz, S. R.

    2013-12-01

    An approach to differentiation of the morphological features of normal and pathological human epidermis on the base of statistical analysis of the local polarization states of laser light forward scattered by in-vitro tissue samples is discussed. The eccentricity and the azimuth angle of local polarization ellipses retrieved for various positions of the focused laser beam on the tissue surface, and the coefficient of collimated transmittance are considered as the diagnostic parameters for differentiation. The experimental data obtained with the psoriasis, discoid lupus erythematosus, alopecia, lichen planus, scabies, demodex, and normal skin samples are presented.

  1. Metastatic Extrapulmonary Small Cell Carcinoma to the Cerebellopontine Angle: A Case Report and Review of the Literature

    Directory of Open Access Journals (Sweden)

    Debebe Theodros

    2015-01-01

    Full Text Available Extrapulmonary small cell carcinomas (EPSCC are rare malignancies with poor patient prognoses. We present the case of a 63-year-old male who underwent surgical resection of a poorly differentiated small cell carcinoma, likely from a small intestinal primary tumor that metastasized to the cerebellopontine angle (CPA. A 63-year-old male presented with mild left facial paralysis, hearing loss, and balance instability. MRI revealed a 15 mm mass in the left CPA involving the internal auditory canal consistent with a vestibular schwannoma. Preoperative MRI eight weeks later demonstrated marked enlargement to 35 mm. The patient underwent a suboccipital craniectomy and the mass was grossly different visually and in consistency from a standard vestibular schwannoma. The final pathology revealed a poorly differentiated small cell carcinoma. Postoperative PET scan identified avid uptake in the small intestine suggestive of either a small intestinal primary tumor or additional metastatic disease. The patient underwent whole brain radiation therapy and chemotherapy and at last follow-up demonstrated improvement in his symptoms. Surgical resection and radiotherapy are potential treatment options to improve survival in patients diagnosed with NET brain metastases. We present the first documented case of skull base metastasis of a poorly differentiated small cell carcinoma involving the CPA.

  2. Performance of the micro-PIC gaseous area detector in small-angle X-ray scattering experiments.

    Science.gov (United States)

    Hattori, Kaori; Tsuchiya, Ken'ichi; Ito, Kazuki; Okada, Yoko; Fujii, Kotaro; Kubo, Hidetoshi; Miuchi, Kentaro; Takata, Masaki; Tanimori, Toru; Uekusa, Hidehiro

    2009-03-01

    The application of a two-dimensional photon-counting detector based on a micro-pixel gas chamber (micro-PIC) to high-resolution small-angle X-ray scattering (SAXS), and its performance, are reported. The micro-PIC is a micro-pattern gaseous detector fabricated by printed circuit board technology. This article describes the performance of the micro-PIC in SAXS experiments at SPring-8. A dynamic range of >10(5) was obtained for X-ray scattering from a polystyrene sphere solution. A maximum counting rate of up to 5 MHz was observed with good linearity and without saturation. For a diffraction pattern of collagen, weak peaks were observed in the high-angle region in one accumulation of photons.

  3. Effect of lithium intercalation on the structure of non-graphitizable carbon: small-angle neutron scattering

    Energy Technology Data Exchange (ETDEWEB)

    Mamun, S.M.; Kamiyama, Takashi [Institute of Materials Structure Science, High Energy Accelerator Research Organization, Tsukuba, Ibaraki (Japan); Nagao, Miki [Department of Chemistry, Kobe Univ., Kobe, Hyogo (JP)] [and others

    2001-03-01

    Recent developments in rechargeable Li-ion battery technology include the use of lithium-carbon compounds instead of metallic anodes. Non-graphitizable carbons offer high capacity as the anode material but it's large irreversible capacity must be solved. The ultimate goals of the present work are to understand the origin of the high capacity and large irreversible capacity in conjunction with the structural change due to Li intercalation and thus to establish a scientific basis for optimizing their performance in real batteries. 'House of cards' model is considered and emphasis is given to find out the size of the pores present in the carbon fibers prepared from an isotropic petroleum pitch and heat treated at 1200degC. Small angle neutron scattering and wide angle neutron scattering results provide enlargement of pores and d-spacing of grapheme layers after Li intercalation. (author)

  4. Development of a One-Dimensional Small-Angle Neutron Scattering Instrument at the University of Illinois TRIGA Reactor Laboratory

    Science.gov (United States)

    Monti, D. A.; Guillermo, N. R.; Hulin, M. J.; Heuser, B. J.; Toreja, A.; Moschetti, T. L.

    1996-03-01

    A small-angle neutron scattering instrument with slit-smeared geometry (1-D SANS) has been constructed at the University of Illinois 1.5 MWatt TRIGA reactor. This facility falls under the general heading of "low-flux research reactors" which typically are not used for neutron scattering research. Low-flux reactors can support neutron scattering research under certain conditions, however. 1-D SANS using elastically-bent crystal optics is one such example [Popovici, et al. (1995). J. Phys. Chem. Solids 56, 1425-1431]. Our instrument uses a pyrolytic graphite pre-monochromator and two elastically-bent Si wafers, all in a (+,+,-) configuration. Instrumental performance including low-angle resolution, on-sample intensity, resolution variability, and cross-section measurement capability will be presented.

  5. Plasma-assisted atomic layer epitaxial growth of aluminum nitride studied with real time grazing angle small angle x-ray scattering

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, Virginia R.; Nepal, Neeraj; Johnson, Scooter D.; Robinson, Zachary R.; Nath, Anindya; Kozen, Alexander C.; Qadri, Syed B.; DeMasi, Alexander; Hite, Jennifer K.; Ludwig, Karl F.; Eddy, Charles R.

    2017-05-01

    Wide bandgap semiconducting nitrides have found wide-spread application as light emitting and laser diodes and are under investigation for further application in optoelectronics, photovoltaics, and efficient power switching technologies. Alloys of the binary semiconductors allow adjustments of the band gap, an important semiconductor material characteristic, which is 6.2 eV for aluminum nitride (AlN), 3.4 eV for gallium nitride, and 0.7 eV for (InN). Currently, the highest quality III-nitride films are deposited by metalorganic chemical vapor deposition and molecular beam epitaxy. Temperatures of 900 °C and higher are required to deposit high quality AlN. Research into depositing III-nitrides with atomic layer epitaxy (ALEp) is ongoing because it is a fabrication friendly technique allowing lower growth temperatures. Because it is a relatively new technique, there is insufficient understanding of the ALEp growth mechanism which will be essential to development of the process. Here, grazing incidence small angle x-ray scattering is employed to observe the evolving behavior of the surface morphology during growth of AlN by ALEp at temperatures from 360 to 480 °C. Increased temperatures of AlN resulted in lower impurities and relatively fewer features with short range correlations.

  6. Effects of small-angle mistilts on dopant visibility in ADF-STEM imaging of nanocrystals

    Energy Technology Data Exchange (ETDEWEB)

    Held, Jacob T.; Duncan, Samuel; Mkhoyan, K. Andre, E-mail: mkhoyan@umn.edu

    2017-06-15

    Highlights: • ADF-STEM is powerful technique for 3D location of substitutionally doped atoms. • The effects of specimen mistilt on ADF-STEM imaging of doped atoms are evaluated. • Visibility changes over 0–30 mrad mistilts are large enough to preclude 3D dopant location. • Dopant visibility is a strong function of specimen mistilt and cannot be ignored. - Abstract: Quantitative ADF-STEM imaging paired with image simulations has proven to be a powerful technique for determining the three dimensional location of substitutionally doped atoms in thin films. Expansion of this technique to lightly-doped nanocrystals requires an understanding of the influence of specimen mistilt on dopant visibility due to the difficulty of accurate orientation determination in such systems as well as crystal movement under the beam. In this study, the effects of specimen mistilt on ADF-STEM imaging are evaluated using germanium-doped silicon nanocrystals as model systems. It is shown that dopant visibility is a strong function of specimen mistilt, and the accuracy of specimen orientation is an important factor in the analysis of three-dimensional dopant location, but the sensitivity to mistilt can be weakened by increasing the STEM probe convergence angle and optimizing ADF detector inner angle.

  7. 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.

  8. Angled Cool-Tip Electrode for Radiofrequency Ablation of Small Superficial Subcapsular Tumors in the Liver: A Feasibility Study

    Energy Technology Data Exchange (ETDEWEB)

    Park, Sung Il [Department of Radiology, Research Institute of Radiological Science, Severance Hospital, Yonsei University College of Medicine, Seoul 03722 (Korea, Republic of); Kim, Il Jung [Department of Radiology, Bucheon St. Mary' s Hospital, College of Medicine, The Catholic University of Korea, Bucheon 14647 (Korea, Republic of); Lee, Shin Jae [Department of Radiology, CHA Bundang Medical Center, CHA University, Seongnam 13496 (Korea, Republic of); Shin, Min Woo; Shin, Won Sun; Chung, Yong Eun; Kim, Gyoung Min; Kim, Man Deuk; Won, Jong Yun; Lee, Do Yun [Department of Radiology, Research Institute of Radiological Science, Severance Hospital, Yonsei University College of Medicine, Seoul 03722 (Korea, Republic of); Choi, Jin Sub [Department of Surgery, Severance Hospital, Yonsei University College of Medicine, Seoul 03722 (Korea, Republic of); Han, Kwang-Hyub [Department of Internal Medicine, Severance Hospital, Yonsei University College of Medicine, Seoul 03722 (Korea, Republic of)

    2016-11-01

    To evaluate the feasibility of angled cool-tip electrode for radiofrequency ablation of small superficial subcapsular liver tumors abutting abdominal wall, in order to traverse normal liver parenchyma, and thereby, obtain favorable configuration of ablation margin. In this study, we retrospectively analyzed 15 small superficial subcapsular liver tumors abutting abdominal wall in 15 patients, treated with radiofrequency ablation from March 2013 to June 2015 using a cool-tip electrode manually modified to create 25–35° angle at the junction between exposed and insulated segments. The tumors were hepatocellular carcinoma (n = 13) and metastases (n = 2: cholangiocellular carcinoma and rectosigmoid cancer), with maximum diameter of 10–26 mm (mean, 15.68 ± 5.29 mm). Under ultrasonographic guidance, the electrode tip was advanced to the depth of the tumors' epicenter about 1 cm from the margin. The tip was re-directed to penetrate the tumor for radiofrequency ablation. Minimal ablation margin was measured at immediate post-treatment CT. Radiological images and medical records were evaluated for success rate, length of minimal ablation margin and complications. Technical success rate of obtaining complete necrosis of the tumors was 100%, with no procedure-related complication. Minimal ablation margin ranged from 3–12 mm (mean, 7.07 ± 2.23 mm). CT/MRI follow-up at 21–1022 days (mean, 519.47 ± 304.51 days) revealed no local recurrence, but distant recurrence in 9 patients. Using an angled cool-tip electrode for radiofrequency ablation of small superficial subcapsular tumors abutting abdominal wall may be a feasible technique for obtaining adequate ablation margin and lower complication rate.

  9. Angled cool-tip electrode for radiofrequency ablation of small superficial subcapsular tumors in the liver: A feasibility study

    Energy Technology Data Exchange (ETDEWEB)

    Park, Sung Il; Shin, Min Woo; Shin, Won Seon [Severance Hospital, Yonsei University College of Medicine, Seoul (Korea, Republic of); and others

    2016-09-15

    To evaluate the feasibility of angled cool-tip electrode for radiofrequency ablation of small superficial subcapsular liver tumors abutting abdominal wall, in order to traverse normal liver parenchyma, and thereby, obtain favorable configuration of ablation margin. In this study, we retrospectively analyzed 15 small superficial subcapsular liver tumors abutting abdominal wall in 15 patients, treated with radiofrequency ablation from March 2013 to June 2015 using a cool-tip electrode manually modified to create 25–35° angle at the junction between exposed and insulated segments. The tumors were hepatocellular carcinoma (n = 13) and metastases (n = 2: cholangiocellular carcinoma and rectosigmoid cancer), with maximum diameter of 10–26 mm (mean, 15.68 ± 5.29 mm). Under ultrasonographic guidance, the electrode tip was advanced to the depth of the tumors' epicenter about 1 cm from the margin. The tip was re-directed to penetrate the tumor for radiofrequency ablation. Minimal ablation margin was measured at immediate post-treatment CT. Radiological images and medical records were evaluated for success rate, length of minimal ablation margin and complications. Technical success rate of obtaining complete necrosis of the tumors was 100%, with no procedure-related complication. Minimal ablation margin ranged from 3–12 mm (mean, 7.07 ± 2.23 mm). CT/MRI follow-up at 21–1022 days (mean, 519.47 ± 304.51 days) revealed no local recurrence, but distant recurrence in 9 patients. Using an angled cool-tip electrode for radiofrequency ablation of small superficial subcapsular tumors abutting abdominal wall may be a feasible technique for obtaining adequate ablation margin and lower complication rate.

  10. Absolute differential cross sections for electron excitation of silver at small scattering angles

    Science.gov (United States)

    Tošić, S. D.; Pejčev, V.; Šević, D.; McEachran, R. P.; Stauffer, A. D.; Marinković, B. P.

    2012-05-01

    We present results of our experimental and theoretical investigations of the electron excitation of the ground 4d105s state of silver. Differential cross sections (DCSs) for the excitation of the first combined resonant 4d105p state (two fine-structure levels with total angular momentum J = 1/2 and 3/2 which cannot be distinguished in the present experiment) were measured at electron-impact energies (E0) of 10, 20, 40, 60, 80 and 100 eV and for a range of scattering angles (θ) from 3° up to 15°. Absolute DCSs were obtained by the normalization of relative differential cross sections to the optical oscillator strengths. The relativistic distorted wave (RDW) method was used to calculate DCSs and generalized oscillator strengths for each level separately and the combined results are compared with the measurements.

  11. The use of magnetic small angle neutron scattering for the detection of flow profiles in magnetic fluids

    Energy Technology Data Exchange (ETDEWEB)

    Odenbach, S.; Gilly, H. [Center of Applied Spacetechnology and Microgravity (ZARM), University of Bremen, Am Fallturm, 28359 Bremen (Germany); Lindner, P. [Institute Laue Langevin, Avenue des Martyrs, BP 156, 38042 Grenoble Cedex (France)

    1999-07-01

    We have investigated the possibility of using magnetic small angle neutron scattering (MSANS) to detect the flow pattern of flow in concentrated magnetic fluids. It has been shown that the anisotropy of the scattering pattern can be determined with appropriate accuracy allowing to identify changes of the anisotropy induced by different flow states. These changes can be used as a measure for flow characteristics in the fluids. In this paper we present the general idea and an experimental demonstration of the concept using a simple convective flow pattern. (Copyright (c) 1999 Elsevier Science B.V., Amsterdam. All rights reserved.)

  12. Calculation of the cluster size distribution functions and small-angle neutron scattering data for C60/N-methylpyrrolidone

    Science.gov (United States)

    Tropin, T. V.; Jargalan, N.; Avdeev, M. V.; Kyzyma, O. A.; Sangaa, D.; Aksenov, V. L.

    2014-01-01

    The aggregate growth in a C60/N-methylpyrrolidone (NMP) solution has been considered in the framework of the approach developed earlier for describing the cluster growth kinetics in fullerene polar solutions. The final cluster size distribution functions in model solutions have been estimated for two fullerene aggregation models including the influence of complex formation on the cluster growth using extrapolations of the characteristics of the cluster state and distribution parameters. Based on the obtained results, the model curves of small-angle neutron scattering have been calculated for a C60/NMP solution at various values of the model parameters.

  13. Limiting cases of the small-angle scattering approximation solutions for the propagation of laser beams in anisotropic scattering media

    Science.gov (United States)

    Box, M. A.; Deepak, A.

    1981-01-01

    The propagation of photons in a medium with strongly anisotropic scattering is a problem with a considerable history. Like the propagation of electrons in metal foils, it may be solved in the small-angle scattering approximation by the use of Fourier-transform techniques. In certain limiting cases, one may even obtain analytic expressions. This paper presents some of these results in a model-independent form and also illustrates them by the use of four different phase-function models. Sample calculations are provided for comparison purposes

  14. Determination of the spatial distribution of multiple fluid phases in porous media by ultra-small-angle neutron scattering

    Energy Technology Data Exchange (ETDEWEB)

    Kainourgiakis, M.; Steriotis, Th. [National Center for Scientific Research ' Demokritos' , 15310 Ag. Paraskevi Attikis, Athens (Greece); Charalambopoulou, G., E-mail: gchar@chem.demokritos.gr [National Center for Scientific Research ' Demokritos' , 15310 Ag. Paraskevi Attikis, Athens (Greece); Strobl, M. [Helmholtz Zentrum Berlin fuer Materialien und Energie, Lise Meitner Campus, Hahn-Meitner-Platz 1, D-14109 Berlin (Germany); Stubos, A. [National Center for Scientific Research ' Demokritos' , 15310 Ag. Paraskevi Attikis, Athens (Greece)

    2010-06-15

    In the present work contrast-matching USANS (ultra-small-angle neutron scattering) was employed in order to determine the spatial distribution of immiscible fluids confined within a macroporous {alpha}-Al{sub 2}O{sub 3} membrane. Water-air as well as water-hydrocarbon and hydrocarbon-air systems were examined and the analysis of the results, also on the basis of a complementary numerical study provided significant information on the behaviour of the multiphase ensemble as it has been demonstrated that the individual fluids occupy certain positions in the pore space, regardless of the actual values of the respective interfacial properties.

  15. Synchrotron radiation small- and wide- angle scattering study of dispergation of Equoral, a novel drug delivery system with cyclosporine A.

    Science.gov (United States)

    Uhríková, D; Andrýsek, T; Funari, S S; Balgavý, P

    2004-08-01

    Equoral oral solution is a novel drug delivery system for cyclosporine consisting mainly of non-ionic surfactants, polyglycerol esters and polyoxyethylated fatty acids aggregates, and gives microdispersions in the aqueous enviroment. To simulate dispergation, Equoral was mixed with varying amounts of water. Changes in the structure of the prepared aggregates were studied using synchrotron x-ray small- and wide-angle scattering. A lamellar phase is the most probable structure, arising spontaneously after dispergation of Equoral in the region of 30-70 wt% H2O.

  16. Antibodies under pressure: A Small-Angle X-ray Scattering study of Immunoglobulin G under high hydrostatic pressure.

    Science.gov (United States)

    König, Nico; Paulus, Michael; Julius, Karin; Schulze, Julian; Voetz, Matthias; Tolan, Metin

    2017-05-26

    In the present work two subclasses of the human antibody Immunoglobulin G (IgG) have been investigated by Small-Angle X-ray Scattering under high hydrostatic pressures up to 5kbar. It is shown that IgG adopts a symmetric T-shape in solution which differs significantly from available crystal structures. Moreover, high-pressure experiments verify the high stability of the IgG molecule. It is not unfolded by hydrostatic pressures of up to 5kbar but a slight increase of the radius of gyration was observed at elevated pressures. Copyright © 2017 Elsevier B.V. All rights reserved.

  17. Cold Neutron Focusing Multiple Biconcave Lenses and Anti-Gravity Prisms for 40m Small Angle Neutron Scattering Instrument

    Energy Technology Data Exchange (ETDEWEB)

    Sim, Jun-Bo; Choi, Sung-Min [Korea Advanced Institute of Science and Technology, Daejeon (Korea, Republic of)

    2007-07-01

    Small angle neutron scattering (SANS) instrument with long flight path is a very powerful tool to investigate the structures of various nanoscale materials. Currently, a new 40m SANS instrument is under development to be installed at HANARO, which will be one of the key facilities for nano-characterization in Korea. To enhance the measurement capability of the 40m SANS, especially in the low Q region, cold neutron focusing and cancellation of gravity effects using multiple biconcave lenses and prisms are suggested. In this paper, we present recent Monte Carlo simulation studies on the refractive focusing and anti-gravity optics.

  18. pH-Responsive Structural Change of PEGylated Amine-Bearing Nanogel Explored by Small Angle X-ray Scattering

    Energy Technology Data Exchange (ETDEWEB)

    Tamura, Goshu; Shinohara, Yuya; Amemiya, Yoshiyuki [Department of Advanced Materials Science, Graduate School of Frontier Sciences, University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8561 (Japan); Akiba, Isamu; Sakurai, Kazuo [Department of Chemistry and Biochemistry, University of Kitakyushu (Japan); Tamura, Atsushi; Oishi, Motoi; Nagasaki, Yukio, E-mail: goshu@x-ray.k.u-tokyo.ac.jp [Department of Materials Science, Graduated School of Pure and Applied Science, University of Tsukuba (Japan)

    2011-01-01

    A PEGylated nanogel sphere containing cross-linked amino groups in its core undergoes dramatic volumetric changes upon pH-change. We measured small angle x-ray scattering from the nanogel and analyzed the data with a core-shell sphere model to determine the core size upon pH-change from 8.0 to 5.8. The protonation of the poly-amine core due to the pH-change increased the core volume by over 300%. Combining the obtained core volume and the absolute intensity, we estimated the change of the core electron density.

  19. Anomalous Small-angle X-ray Scattering Study on Aggregation of a Block Copolymer in a Selective Solvent

    Energy Technology Data Exchange (ETDEWEB)

    Sakou, Megumi; Takechi, Atsuro; Sakurai, Kazuo; Akiba, Isamu [Department of Chemistry, University of Kitakyushu (Japan); Handa, Masashi; Shinohara, Yuya; Amemiya, Yoshiyuki [Department of Advanced Materials Science, University of Kyoto (Japan); Masunaga, Hiroyasu; Ogawa, Hiroki; Yagi, Naoto, E-mail: akiba@env.kitakyu-u.ac.jp [Japan Synchrotron Research Institute (Japan)

    2011-01-01

    Anomalous small-angle X-ray Scattering (ASAXS) analysis for poly(4-vinylphenol)-b-poly(4-bromostyrene) (PVPh-b-PBrS) in N,N,N',N'-tetramethyl ethylene diamine (TMEDA) solution was examined. The ASAXS measurements, executed at three different energies, provided the separation of the scattering of the Br atoms from whole system. The energy-dependent term in the SAXS profile, which is corresponding to the form factor of PBrS domain, sufficiently agree with the SAXS profile calculated for hard sphere with 41 nm radius. Therefore, the PBrS chains assemble into spherical core with 41 nm radius in TMEDA solution.

  20. Small-angle Thomson scattering of ultrafast laser pulses for bright, sub-100-fs x-ray radiation

    Directory of Open Access Journals (Sweden)

    Yuelin Li

    2002-04-01

    Full Text Available We propose a scheme for bright sub-100-fs x-ray radiation generation using small-angle Thomson scattering. Coupling high-brightness electron bunches with high-power ultrafast laser pulses, radiation with photon energies between 8 and 40 keV can be generated with pulse duration comparable to that of the incoming laser pulse and with peak spectral brightness close to that of the third-generation synchrotron light sources of ∼10^{20} photons s^{-1} mm^{-2} mrad^{-2} per 10^{-3} bandwidth. A preliminary dynamic calculation is performed to understand the property of this novel scattering scheme with relativistic laser intensities.

  1. Lateral structural variations in thin cellulose layers investigated by microbeam grazing incidence small-angle X-ray scattering

    Energy Technology Data Exchange (ETDEWEB)

    Roth, S.V. [HASYLAB at DESY, Notkestr. 85, D-22603 Hamburg (Germany)]. E-mail: sroth@esrf.fr; Artus, G.R.J. [Phys.-Chem. Inst., Univ. Zurich, Winterthurerstr. 190, CH-8057 Zurich (Switzerland); Rankl, M. [Phys.-Chem. Inst., Univ. Zurich, Winterthurerstr. 190, CH-8057 Zurich (Switzerland); Seeger, S. [Phys.-Chem. Inst., Univ. Zurich, Winterthurerstr. 190, CH-8057 Zurich (Switzerland); Burghammer, M. [ESRF, B.P. 220, F-38043 Grenoble Cedex 9 (France); Riekel, C. [ESRF, B.P. 220, F-38043 Grenoble Cedex 9 (France); Mueller-Buschbaum, P. [TU Muenchen, Phy.-Dept. E13, James-Franck-Str.1, D-85748 Garching (Germany)

    2005-02-28

    The Langmuir-Blodgett technique is a powerful tool to obtain large-scale thin films. We investigate a thin layer of modified cellulose by atomic force microscopy and microbeam grazing-incidence small angle X-ray scattering. We probe the lateral nanostructure of the as-prepared cellulose layer. The results indicate a lateral structural variation in the arrangement of the cellulose molecules parallel to the dipping direction. These variations occur on a length scale on the order of 100{mu}m.

  2. Electropolymerized nanoporous polymeric SPME coatings: preparation and characterization by small angle X-ray scattering and scanning electron microscopy.

    Science.gov (United States)

    Buszewski, Boguslaw; Olszowy, Pawel; Pikus, Stanislaw; Kozak, Maciej

    Polymeric polypyrrole and polythiophene solid phase microextraction (SPME) coatings were prepared using electropolymerization with a linear sweep voltammetry technique. Physicochemical properties were measured using different methods, in particular small angle X-ray scattering and scanning electron microscopy. By using innovative approaches for pore size measurement, we were able to calculate a maximum of the pore size range from 80 to 90 nm. Additionally, film thicknesses measured from 90 to 150 μm. Using scanning electron microscopy, we describe the characteristics of polymer growth on the support surface.

  3. Small-angle X-ray scattering: a bridge between RNA secondary structures and three-dimensional topological structures

    Energy Technology Data Exchange (ETDEWEB)

    Fang, Xianyang [National Inst. of Health (NIH), Bethesda, MD (United States). National Cancer Inst., NCI Small Angle X-ray Scattering Core Facility; Stagno, Jason R. [National Inst. of Health (NIH), Bethesda, MD (United States). National Cancer Inst., Protein-Nucleic Acid Interaction Section, Structural Biophysics Lab.; Bhandari, Yuba R. [National Inst. of Health (NIH), Bethesda, MD (United States). National Cancer Inst., Protein-Nucleic Acid Interaction Section, Structural Biophysics Lab.; Zuo, Xiaobing [Argonne National Lab. (ANL), Argonne, IL (United States). Advanced Photon Source (APS); Wang, Yun-Xing [National Inst. of Health (NIH), Bethesda, MD (United States). National Cancer Inst., NCI Small Angle X-ray Scattering Core Facility; National Inst. of Health (NIH), Bethesda, MD (United States). National Cancer Inst., Protein-Nucleic Acid Interaction Section, Structural Biophysics Lab.

    2015-02-01

    Whereas the structures of small to medium-sized well folded RNA molecules often can be determined by either X-ray crystallography or NMR spectroscopy, obtaining structural information for large RNAs using experimental, computational, or combined approaches remains a major interest and challenge. RNA is very sensitive to small-angle X-ray scattering (SAXS) due to high electron density along phosphate-sugar backbones, whose scattering contribution dominates SAXS intensity. For this reason, SAXS is particularly useful in obtaining global RNA structural information that outlines backbone topologies and, therefore, molecular envelopes. Such information is extremely valuable in bridging the gap between the secondary structures and three-dimensional topological structures of RNAmolecules, particularly those that have proven difficult to study using other structuredetermination methods. Here we review published results of RNA topological structures derived from SAXS data or in combination with other experimental data, as well as details on RNA sample preparation for SAXS experiments.

  4. Segment-segment interactions of poly(N-isopropylacrylamide) in aqueous methanol solutions by using small-angle scattering

    CERN Document Server

    Shimizu, S; Furusaka, M

    2002-01-01

    Small-angle neutron and X-ray scattering from semidilute solutions of poly(N-isopropylacrylamide) in D sub 2 O, methanol and methanol-water mixtures has been measured in the poor solvent regime. The binary and the ternary cluster integrals of polymer segments were determined from the concentration dependence of the correlation length at several temperatures just below the lower critical solution temperature. Then, contributions of segment-segment interactions to the entropy and the enthalpy have been calculated from the temperature dependence of interaction parameters and it has been found that both values are positive in the D sub 2 O and the methanol-water systems at a small content of methanol, while both values are negative in the other system. (orig.)

  5. Freeform lens design for providing LED small angle illumination in underwater application

    Science.gov (United States)

    Zhang, Xiaohui; Chen, Chen

    2015-08-01

    With high light efficiency and long aging life, LED solid-state light source has attracted much attention in underwater application, such as optical communication and imaging. But, the large divergence angle of LED illumination has been a big challenge in practical underwater application, such as the light attenuation in water and then the decreased signal-to-noise ratio. Source-target map is a vital method in illumination optics design, and the focus is to solve numerically differential equations and then construct the freeform surface. To achieve high accuracy freeform surface, an improved method is suggested and optimized through much more advanced and accuracy Runge-Kutta method, which is different from the original design one through Euler method. The designed lens is simulated by ray trace software TracePro, and the simulation results show that the uniformity of 0.8 and the efficacy of 0.6 is obtained. While as, the method is proven to be effective, and also the accuracy of the smooth freeform surface is strengthened. One designed illumination lens is fabricated by computer numeric control (CNC) machine to demonstrate the design experimentally.

  6. Maximizing Heat Dissipation via Target Optimization of the Small-Angle Slot Divertor

    Science.gov (United States)

    Covele, Brent; Halpern, Federico; Casali, Livia; Canik, John; Thomas, Dan; Guo, Houyang

    2017-10-01

    The planned SAS 2 divertor uses a combination of grazing target angles and closure to direct recycling neutrals near the strike point, thus facilitating detachment onset. SAS 2 should also provide adequate pumping efficiency to be consistent with high-power steady-state scenarios on DIII-D. Initial SOLPS results indicate significantly higher neutral densities and lower electron temperatures in the SAS 2 slot, compared to a closed reference divertor model with baseline plasma profiles appropriate for high power. A systematic optimization of the parameterized SAS 2 target shape is performed in SOLPS to further reduce target heat fluxes and temperatures at lowest upstream density. To speed up the target optimization process, target neutral densities calculated by Eirene act as a performance metric by proxy for detachment facilitation. The efficacy of this proxy metric is discussed. Results are also presented from SAS 2 neutral pumping simulations in Eirene with a stationary background plasma. The feasibility of mutually satisfactory particle control and detachment control is discussed. Work supported under USDOE Cooperative Agreements DE-FC02-04ER54698 and DE-AC05-00OR22725.

  7. Small-angle neutron scattering study of sodium cholate and sodium ...

    Indian Academy of Sciences (India)

    Unknown

    31. Kooser R G, Volland W V and Freed J H 1969 J. Chem. Phys. 50 5243. 32. Blow D M and Rich A 1959 Nature (London) 182 3566. 33. Esposito G and Giglio E 1987 J. Phys. Chem. 91 356. 34. Small D M 1968 Adv. Chem. Ser. 84 31. 35. Dembo A T, Sosfenov N I and Feigin L A 1966 Sov. Phys. Crystallogr. (Engl. Transl.) ...

  8. Small angle X-ray and neutron scattering from solutions of biological macromolecules

    CERN Document Server

    Svergun, Dmitri I; May, Roland P; Timmins, Peter A

    2013-01-01

    In this book, following the presentation of the basics of scattering from isotropic macromolecular solutions, modern instrumentation, experimental practice and advanced analysis techniques are explained. Advantages of X-rays (rapid data collection, small sample volumes) and of neutrons (contrast variation by hydrogen/deuterium exchange) are specifically highlighted. Examples of applications of the technique to different macromolecular systems are considered with specific emphasis on the synergistic use of SAXS/SANS with other structural, biophysical and computational techniques.

  9. Accurate small and wide angle x-ray scattering profiles from atomic models of proteins and nucleic acids

    Science.gov (United States)

    Nguyen, Hung T.; Pabit, Suzette A.; Meisburger, Steve P.; Pollack, Lois; Case, David A.

    2014-12-01

    A new method is introduced to compute X-ray solution scattering profiles from atomic models of macromolecules. The three-dimensional version of the Reference Interaction Site Model (RISM) from liquid-state statistical mechanics is employed to compute the solvent distribution around the solute, including both water and ions. X-ray scattering profiles are computed from this distribution together with the solute geometry. We describe an efficient procedure for performing this calculation employing a Lebedev grid for the angular averaging. The intensity profiles (which involve no adjustable parameters) match experiment and molecular dynamics simulations up to wide angle for two proteins (lysozyme and myoglobin) in water, as well as the small-angle profiles for a dozen biomolecules taken from the BioIsis.net database. The RISM model is especially well-suited for studies of nucleic acids in salt solution. Use of fiber-diffraction models for the structure of duplex DNA in solution yields close agreement with the observed scattering profiles in both the small and wide angle scattering (SAXS and WAXS) regimes. In addition, computed profiles of anomalous SAXS signals (for Rb+ and Sr2+) emphasize the ionic contribution to scattering and are in reasonable agreement with experiment. In cases where an absolute calibration of the experimental data at q = 0 is available, one can extract a count of the excess number of waters and ions; computed values depend on the closure that is assumed in the solution of the Ornstein-Zernike equations, with results from the Kovalenko-Hirata closure being closest to experiment for the cases studied here.

  10. Accurate small and wide angle x-ray scattering profiles from atomic models of proteins and nucleic acids.

    Science.gov (United States)

    Nguyen, Hung T; Pabit, Suzette A; Meisburger, Steve P; Pollack, Lois; Case, David A

    2014-12-14

    A new method is introduced to compute X-ray solution scattering profiles from atomic models of macromolecules. The three-dimensional version of the Reference Interaction Site Model (RISM) from liquid-state statistical mechanics is employed to compute the solvent distribution around the solute, including both water and ions. X-ray scattering profiles are computed from this distribution together with the solute geometry. We describe an efficient procedure for performing this calculation employing a Lebedev grid for the angular averaging. The intensity profiles (which involve no adjustable parameters) match experiment and molecular dynamics simulations up to wide angle for two proteins (lysozyme and myoglobin) in water, as well as the small-angle profiles for a dozen biomolecules taken from the BioIsis.net database. The RISM model is especially well-suited for studies of nucleic acids in salt solution. Use of fiber-diffraction models for the structure of duplex DNA in solution yields close agreement with the observed scattering profiles in both the small and wide angle scattering (SAXS and WAXS) regimes. In addition, computed profiles of anomalous SAXS signals (for Rb(+) and Sr(2+)) emphasize the ionic contribution to scattering and are in reasonable agreement with experiment. In cases where an absolute calibration of the experimental data at q = 0 is available, one can extract a count of the excess number of waters and ions; computed values depend on the closure that is assumed in the solution of the Ornstein-Zernike equations, with results from the Kovalenko-Hirata closure being closest to experiment for the cases studied here.

  11. Molecular conformation of the full-length tumor suppressor NF2/Merlin--a small-angle neutron scattering study.

    Science.gov (United States)

    Ali Khajeh, Jahan; Ju, Jeong Ho; Atchiba, Moussoubaou; Allaire, Marc; Stanley, Christopher; Heller, William T; Callaway, David J E; Bu, Zimei

    2014-07-29

    The tumor suppressor protein Merlin inhibits cell proliferation upon establishing cell-cell contacts. Because Merlin has high level of sequence similarity to the Ezrin-Radixin-Moesin family of proteins, the structural model of Ezrin-Radixin-Moesin protein autoinhibition and cycling between closed/resting and open/active conformational states is often employed to explain Merlin function. However, recent biochemical studies suggest alternative molecular models of Merlin function. Here, we have determined the low-resolution molecular structure and binding activity of Merlin and a Merlin(S518D) mutant that mimics the inactivating phosphorylation at S518 using small-angle neutron scattering and binding experiments. Small-angle neutron scattering shows that, in solution, both Merlin and Merlin(S518D) adopt a closed conformation, but binding experiments indicate that a significant fraction of either Merlin or Merlin(S518D) is capable of binding to the target protein NHERF1. Upon binding to the phosphatidylinositol 4,5-bisphosphate lipid, the wild-type Merlin adopts a more open conformation than in solution, but Merlin(S518D) remains in a closed conformation. This study supports a rheostat model of Merlin in NHERF1 binding and contributes to resolving a controversy about the molecular conformation and binding activity of Merlin. Copyright © 2014 Elsevier Ltd. All rights reserved.

  12. On-going development on MINT's small angle neutron scattering (SANS) facility upgrading and related research activities

    Energy Technology Data Exchange (ETDEWEB)

    Mohamed, Abdul Aziz Bin; Mohd, Shukri Bin; Muhammad, Azali Bin [Malaysian Institute for Nuclear Technology Research (MINT), Kajang (Malaysia)

    2003-03-01

    The TRIGA MARK II Research reactor at the Malaysian Institute for Nuclear Research (MINT) was commissioned in July 1982: next year will be its 20 year criticality. Since then various works have been performed to utilize the neutrons produced from this steady state reactor. Projects undertaken are the development and utilization of the Neutron Radiography (MyNR) and Small Angle Neutron Scattering (MySANS) facilities. Materials research, together with traditional scientific interest in understanding matter at the atomic scale, requires detail knowledge of the arrangement and the dynamics of the atoms or molecules. To enhance Malaysian research and development in this area in particular nanoparticle and nanostructure, MINT has made a dedicated commitment to strengthen the utilizing and maintaining the existing small angle neutron scattering facility to its optimal. This paper describes the recent progress of the MySANS facility and its proposed applications in materials science and technology research and education. Both management and technical strategies are generally explained. In addition a future work plan is also noted. (author)

  13. X-ray diffraction study with small- and wide-angle simultaneous measurement of polymorphic crystallization of triacylglycerols

    Energy Technology Data Exchange (ETDEWEB)

    Ueno, Satoru [Hiroshima Univ., Faculty of Applied Biological Science, Higashi-Hiroshima, Hiroshima (Japan)

    2002-01-01

    Polymorphism of triacylglycerols (TAGs) is an important phenomenon which influences the physical chemical properties of fats employed in foods, pharmaceuticals, cosmetics etc. In particular, precise analysis of kinetic properties of polymorphic crystallization is closely related to technical control of fat crystallization in confectionery and food industry. In the melt-mediated crystallization, which is one of the typical methods of crystallizing the more stable form for industrial use, the more stable form is induced by rapidly melting the less stable forms. Recently, X-ray diffraction spectroscopy using a synchrotron radiation source has been used in study of dynamic processes of polymorphic transformations of many TAGs. This approach has allowed us to gain a better understanding of the kinetics of processes occurring during the polymorphic crystallization and transformations of TAGs at the molecular level. In the present study, polymorphic crystallization of TAG has been examined with the time-resolved X-ray diffraction method with small- and wide-angle simultaneous measurement using synchrotron radiation. The main result is as follows: the melt mediation gave rise to the formation of a liquid crystalline structure having long spacing values of 5.1 nm and 4.6 nm in SOS (sn-1,3-distearoyl-2-oleoyl glycerol). Consequently, the use of the time-resolved X-ray diffraction method with small- and wide-angle simultaneous measurement using synchrotron radiation unveiled quite newer aspects of the polymorphic crystallization of the triacylglycerols from neat liquid, which were not detectable in conventional XRD techniques. (author)

  14. Attitude angle anti-windup control of small size unmanned helicopter

    Science.gov (United States)

    Shao, Taizhou; Long, Haihui; Zhao, Jiankang; Xia, Xuan; Yang, Guang

    2017-01-01

    This paper researches the small-size unmanned helicopter attitude control problem with actuator saturation limit. Traditional approach for this problem is often based on an accurate dynamic model which is complicated and difficult to achieve in engineering. In this paper, we propose an anti-windup PID approach which does not rely on sophicated helicopter dynamic model. The anti-windup PID controller is established by adding a phase-lead compensator to the conventional PID controller. The performance and merits of this proposed controller are exemplified by the simulations between the conventional PID controller and the anti-windup PID controller.

  15. The aggregation behavior of zinc-free insulin studied by small-angle neutron scattering

    DEFF Research Database (Denmark)

    Pedersen, J.S.; Hansen, S.; Bauer, R.

    1994-01-01

    -particle correlation effects, were obtained by an indirect Fourier transformation, omitting the data at small scattering vectors, which are influenced by these effects. By this procedure the weight-averaged molecular mass and the average radius of gyration were determined. These parameters vary from 1.3 times...... the monomer mass and 14 Angstrom to 6.8 times the monomer mass and 31 Angstrom, respectively. The mass distribution between the oligomers was determined by a model based on the crystal structure of zinc-free insulin. The results from this model and the Fourier transformations have been compared...

  16. Determination of structural changes of dispersed clay platelets in a polymer blend during solid-state rheological property measurement by small-angle X-ray scattering

    CSIR Research Space (South Africa)

    Bandyopadhyay, J

    2011-05-01

    Full Text Available -1 Polymer Volume 52, Issue 12, 26 May 2011, Pages 2628?2642 Determination of structural changes of dispersed clay platelets in a polymer blend during solid-state rheological property measurement by small-angle X-ray scattering ? Jayita Bandyopadhyaya... frequency and temperature sweep tests. Graphical abstract Keywords ? Blend composites; ? Small-angle X-ray scattering; ? Solid-state rheology ...

  17. Numerical Calculation of Small-Angle Collimator Wakefields for Short Bunches

    Energy Technology Data Exchange (ETDEWEB)

    Bane, Karl LF

    2003-06-16

    Collimators are used to eliminate halo particles from the beam. To relax the wakefield effects a gradual transition from a large to a small aperture is used. However, the existing computer codes face severe problems for long tapered transitions. Two main sources of the problems are the grid dispersion and the staircase geometry approximation. Using recently developed time domain numerical approach, which is able to model curved boundaries and does not suffer from dispersion in longitudinal direction, we calculate the short-range geometric wakefields of the TESLA and NLC collimators. Wake fields and corresponding integral parameters are given for bunches of different length. The numerical results are compared to measurements and to analytical estimations. The applicability range for the analytical formulas is highlighted.

  18. Structure of clathrin-coated vesicles from small-angle scattering experiments

    DEFF Research Database (Denmark)

    Pedersen, J.S.

    1993-01-01

    used for interpreting the data has spherical symmetry and explicitly takes into account polydispersity, which is described by a Gaussian distribution. A constant thickness of the clathrin coats is assumed. The fitting of the model shows that the coated vesicles consist of a low-density outer protein...... shell (clathrin) and a central protein shell (accessory polypeptides and receptors) of approximately six times higher density. For the X-ray scattering and neutron contrast variation data. the polydispersity of the samples is of the order of 90 angstrom (full-width-at-half-maximum value) and the average...... is situated in the central high-density shell, which gives a large amount of protein in the lipid membrane. The densities of the central shell and the lipid membrane show that the hydration is small in the central region. A comparison of the total mass, the mass distribution, and the structure of the average...

  19. Small-angle light scattering symmetry breaking in polymer-dispersed liquid crystal films with inhomogeneous electrically controlled interface anchoring

    Energy Technology Data Exchange (ETDEWEB)

    Loiko, V. A., E-mail: loiko@ifanbel.bas-net.by; Konkolovich, A. V. [National Academy of Sciences of Belarus, Stepanov Institute of Physics (Belarus); Zyryanov, V. Ya. [Russian Academy of Sciences, Kirensky Institute of Physics, Federal Research Center “Krasnoyarsk Scientific Center,” Siberian Branch (Russian Federation); Miskevich, A. A. [National Academy of Sciences of Belarus, Stepanov Institute of Physics (Belarus)

    2017-03-15

    We have described the method of analyzing and reporting on the results of calculation of the small-angle structure of radiation scattered by a polymer-dispersed liquid crystal film with electrically controlled interfacial anchoring. The method is based on the interference approximation of the wave scattering theory and the hard disk model. Scattering from an individual liquid crystal droplet has been described using the anomalous diffraction approximation extended to the case of droplets with uniform and nonuniform interface anchoring at the droplet–polymer boundary. The director field structure in an individual droplet is determined from the solution of the problem of minimizing the volume density of the free energy. The electrooptical effect of symmetry breaking in the angular distribution of scattered radiation has been analyzed. This effect means that the intensities of radiation scattered within angles +θ{sub s} and–θ{sub s} relative to the direction of illumination in the scattering plane can be different. The effect is of the interference origin and is associated with asymmetry of the phase shift of the wavefront of an incident wave from individual parts of the droplet, which appears due to asymmetry of the director field structure in the droplet, caused by nonuniform anchoring of liquid crystal molecules with the polymer on its surface. This effect is analyzed in the case of normal illumination of the film depending on the interfacial anchoring at the liquid crystal–polymer interface, the orientation of the optical axes of droplets, their concentration, sizes, anisometry, and polydispersity.

  20. Beam splitting target reflector based compensation for angular drift of laser beam in laser autocollimation of measuring small angle deviations

    Energy Technology Data Exchange (ETDEWEB)

    Zhu Fan; Tan Jiubin; Cui Jiwen [Center of Ultra-precision Optoelectronic Instrument Engineering, Harbin Institute of Technology, Harbin 150080 (China)

    2013-06-15

    Beam splitting target reflector based compensation for the angular drift of laser beam in laser autocollimation is proposed in this article to improve the measurement accuracy and stability of small angle deviations. A beam splitting target reflector is used to replace the plane mirror in laser autocollimation to generate a reference beam when returning the measurement beam. The reference beam and measurement beam have the same angular drift, but have different sensitivities to the rotation angle of the reflector due to the unique characteristics of the reflector. Thus, the angular drift of laser beam in laser autocollimation can be compensated in real time by using the drift of reference beam. Experimental results indicate that an output stability of 0.085 arc sec in 2 h can be achieved after compensation. And a measurement accuracy of {+-}0.032 arc sec can be obtained over the range of {+-}1190 arc sec with an effective resolution of 0.006 arc sec. It is confirmed that the compensation method for the angular drift of laser beam is necessary for improving the measurement accuracy and stability in laser autocollimation.

  1. Beam splitting target reflector based compensation for angular drift of laser beam in laser autocollimation of measuring small angle deviations.

    Science.gov (United States)

    Zhu, Fan; Tan, Jiubin; Cui, Jiwen

    2013-06-01

    Beam splitting target reflector based compensation for the angular drift of laser beam in laser autocollimation is proposed in this article to improve the measurement accuracy and stability of small angle deviations. A beam splitting target reflector is used to replace the plane mirror in laser autocollimation to generate a reference beam when returning the measurement beam. The reference beam and measurement beam have the same angular drift, but have different sensitivities to the rotation angle of the reflector due to the unique characteristics of the reflector. Thus, the angular drift of laser beam in laser autocollimation can be compensated in real time by using the drift of reference beam. Experimental results indicate that an output stability of 0.085 arc sec in 2 h can be achieved after compensation. And a measurement accuracy of ±0.032 arc sec can be obtained over the range of ±1190 arc sec with an effective resolution of 0.006 arc sec. It is confirmed that the compensation method for the angular drift of laser beam is necessary for improving the measurement accuracy and stability in laser autocollimation.

  2. Structural changes in C–S–H gel during dissolution: Small-angle neutron scattering and Si-NMR characterization

    Energy Technology Data Exchange (ETDEWEB)

    Trapote-Barreira, Ana, E-mail: anatrapotebarreira@gmail.com [Institute of Environmental Assessment and Water Research (IDAEA), Barcelona 08034, Catalonia (Spain); Porcar, Lionel [National Institute of Standards and Technology (NIST), Gaithersburg, MD 20899 (United States); Large Scale Structure Group, Institut Laue Langevin, Grenoble (France); Cama, Jordi; Soler, Josep M. [Institute of Environmental Assessment and Water Research (IDAEA), Barcelona 08034, Catalonia (Spain); Allen, Andrew J. [National Institute of Standards and Technology (NIST), Gaithersburg, MD 20899 (United States)

    2015-06-15

    Flow-through experiments were conducted to study the calcium–silicate–hydrate (C–S–H) gel dissolution kinetics. During C–S–H gel dissolution the initial aqueous Ca/Si ratio decreases to reach the stoichiometric value of the Ca/Si ratio of a tobermorite-like phase (Ca/Si = 0.83). As the Ca/Si ratio decreases, the solid C–S–H dissolution rate increases from (4.5 × 10{sup −} {sup 14} to 6.7 × 10{sup −} {sup 12}) mol m{sup −} {sup 2} s{sup −} {sup 1}. The changes in the microstructure of the dissolving C–S–H gel were characterized by small-angle neutron scattering (SANS) and {sup 29}Si magic-angle-spinning nuclear magnetic resonance ({sup 29}Si-MAS NMR). The SANS data were fitted using a fractal model. The SANS specific surface area tends to increase with time and the obtained fit parameters reflect the changes in the nanostructure of the dissolving solid C–S–H within the gel. The {sup 29}Si MAS NMR analyses show that with dissolution the solid C–S–H structure tends to a more ordered tobermorite structure, in agreement with the Ca/Si ratio evolution.

  3. Small-angle light scattering symmetry breaking in polymer-dispersed liquid crystal films with inhomogeneous electrically controlled interface anchoring

    Science.gov (United States)

    Loiko, V. A.; Konkolovich, A. V.; Zyryanov, V. Ya.; Miskevich, A. A.

    2017-03-01

    We have described the method of analyzing and reporting on the results of calculation of the small-angle structure of radiation scattered by a polymer-dispersed liquid crystal film with electrically controlled interfacial anchoring. The method is based on the interference approximation of the wave scattering theory and the hard disk model. Scattering from an individual liquid crystal droplet has been described using the anomalous diffraction approximation extended to the case of droplets with uniform and nonuniform interface anchoring at the droplet-polymer boundary. The director field structure in an individual droplet is determined from the solution of the problem of minimizing the volume density of the free energy. The electrooptical effect of symmetry breaking in the angular distribution of scattered radiation has been analyzed. This effect means that the intensities of radiation scattered within angles +θ s and-θ s relative to the direction of illumination in the scattering plane can be different. The effect is of the interference origin and is associated with asymmetry of the phase shift of the wavefront of an incident wave from individual parts of the droplet, which appears due to asymmetry of the director field structure in the droplet, caused by nonuniform anchoring of liquid crystal molecules with the polymer on its surface. This effect is analyzed in the case of normal illumination of the film depending on the interfacial anchoring at the liquid crystal-polymer interface, the orientation of the optical axes of droplets, their concentration, sizes, anisometry, and polydispersity.

  4. Characterization of pore structure in metal-organic framework by small-angle X-ray scattering.

    Science.gov (United States)

    Tsao, Cheng-Si; Yu, Ming-Sheng; Chung, Tsui-Yun; Wu, Hsiu-Chu; Wang, Cheng-Yu; Chang, Kuei-Sen; Chen, Hsin-Lung

    2007-12-26

    MOF-5-like crystals were studied by small-angle X-ray scattering (SAXS) to reveal, both quantitatively and qualitatively, their real structural details, including pore surface characteristics, pore shape, size distribution, specific surface area (SSA), spatial distribution, and pore-network structure. A combined SAXS and wide-angle X-ray scattering (WAXS) experiment was conducted to investigate the variation of the pore structure with the MOF-5 crystalline phase produced at different cooling rates. The SSA of the MOF-5 crystals synthesized herein spanned a broad range from approximately 3100 to 800 m2/g. The real pore structures were divided into two regimes. In regime I the material consisted mainly of micropores of radius approximately 8 A as well as mesopores of radius 120 approximately 80 A. The structure in regime II was a fractal network of aggregated mesopores with radius >or=32 A as the monomer, reducing SSA and hydrogen uptake capacity at room temperature. The two regimes can be manipulated by controlling the synthesis parameters. The concurrent evolution of pore structure and crystalline phase during heating for solvent removal was also revealed by the in-situ SAXS/WAXS measurement. The understanding of the impact of the real pore structure on the properties is important to establish a favorable synthetic approach for markedly improving the hydrogen storage capacity of MOF-5.

  5. X-ray crystal structure and small-angle X-ray scattering of sheep liver sorbitol dehydrogenase

    DEFF Research Database (Denmark)

    Yennawar, Hemant; Møller, Magda; Gillilan, Richard

    2011-01-01

    The X-ray crystal structure of sheep liver sorbitol dehydrogenase (slSDH) has been determined using the crystal structure of human sorbitol dehydrogenase (hSDH) as a molecular-replacement model. slSDH crystallized in space group I222 with one monomer in the asymmetric unit. A conserved tetramer...... that superposes well with that seen in hSDH (despite belonging to a different space group) and obeying the 222 crystal symmetry is seen in slSDH. An acetate molecule is bound in the active site, coordinating to the active-site zinc through a water molecule. Glycerol, a substrate of slSDH, also occupies...... the substrate-binding pocket together with the acetate designed by nature to fit large polyol substrates. The substrate-binding pocket is seen to be in close proximity to the tetramer interface, which explains the need for the structural integrity of the tetramer for enzyme activity. Small-angle X...

  6. Characterization of oligomerization of a peptide from the ebola virus glycoprotein by small-angle neutron scattering

    Energy Technology Data Exchange (ETDEWEB)

    Egorov, V. V., E-mail: vlaegur@omrb.pnpi.spb.ru [National Research Center “Kurchatov Institute”, Konstantinov Petersburg Nuclear Physics Institute (Russian Federation); Gorshkov, A. N. [Ministry of Health of the Russian Federation, Research Institute of Influenza (Russian Federation); Murugova, T. N. [Joint Institute for Nuclear Research (Russian Federation); Vasin, A. V. [Ministry of Health of the Russian Federation, Research Institute of Influenza (Russian Federation); Lebedev, D. V.; Isaev-Ivanov, V. V. [National Research Center “Kurchatov Institute”, Konstantinov Petersburg Nuclear Physics Institute (Russian Federation); Kiselev, O. I. [Ministry of Health of the Russian Federation, Research Institute of Influenza (Russian Federation)

    2016-01-15

    Transmission electron microscopy (TEM) and small-angle neutron scattering (SANS) studies showed that model peptides QNALVCGLRQ (G33) and QNALVCGLRG (G31) corresponding to region 551–560 of the GP protein of the Sudan Ebola virus are prone to oligomerization in solution. Both peptides can form amyloid-like fibrills. The G33 peptide forms fibrils within one day of incubation, whereas the fibrillogenesis of the G31 peptide is observed only after incubation for several months. The possible role of the observed processes in the pathogenesis and the possibility of applying a combination of the TEM and SANS techniques to search for new compounds that are able to influence the protein oligomerization are discussed.

  7. Spin-echo small-angle neutron scattering study of the structure organization of the chromatin in biological cell

    Science.gov (United States)

    Iashina, E. G.; Bouwman, W. G.; Duif, C. P.; Filatov, M. V.; Grigoriev, S. V.

    2017-06-01

    Spin-echo small-angle scattering (SESANS) technique is a method to measure the structure of materials from nano- to micrmeter length scales. This method could be important for studying the packaging of DNA in the eukaryotic cell. We measured the SESANS function from chicken erythrocyte nuclei which is well fitted by the exponential function G(z) = exp(-z/ξ), where ξ is the correlation length of a nucleus (in experimental data ξ = 3, 3 μm). The exponential decay of G(z) corresponds to the logarithmic pair correlation function γ(r) = ln(ξ/r). As the sensitivity of the SESANS signal depends on the neutron wavelength, we propose the SESANS setup with the changeable wavelength in the range from 2 to 12 Å. Such option allows one to study in great detail the internal structure of the biological cell in the length scale from 10-2 μm to 10 μm.

  8. The study of the structural properties of very low viscosity sodium alginate by small-angle neutron scattering

    Energy Technology Data Exchange (ETDEWEB)

    Badita, C. R., E-mail: ramona@tandem.nipne.ro [Horia Hulubei National Institute of Physics and Nuclear Engineering, Reactorului 30, RO-077125, POB-MG6, Magurele-Bucharest, Romania, ramona@tandem.nipne.ro, daranghe@nipne.ro (Romania); University of Bucharest, Faculty of Physics, Atomiştilor 405, CP MG - 11, RO – 077125, Bucharest-Magurele (Romania); Aranghel, D., E-mail: daranghe@nipne.ro [Horia Hulubei National Institute of Physics and Nuclear Engineering, Reactorului 30, RO-077125, POB-MG6, Magurele-Bucharest, Romania, ramona@tandem.nipne.ro, daranghe@nipne.ro (Romania); Extreme Light Intrastructure Nuclear Physics (ELI-NP), Reactorului 30, RO-077125, POB-MG6, Magurele-Bucharest (Romania); Radulescu, A. [Forschungszentrum Jülich GmbH, Jülich Centre for Neutron Science, 85747 Garching (Germany); Anitas, E. M. [Horia Hulubei National Institute of Physics and Nuclear Engineering, Reactorului 30, RO-077125, POB-MG6, Magurele-Bucharest, Romania, ramona@tandem.nipne.ro, daranghe@nipne.ro (Romania); Joint Institute for Nuclear Research, 141980 Dubna, Moscow region (Russian Federation)

    2016-03-25

    Sodium alginate is a linear polymer extract from brown algae and it is used in the biomedical, food, cosmetics and pharmaceutical industries as solution property modifiers and gelling agents. But despite the extensive studies of the alginate gelation process, still some fundamental questions remain unresolved. The fractal behavior of very low viscosity sodium alginate solutions and their influence on the critical gelation of alginate induced by Ca{sup 2+} ions were investigated using Small-Angle Neutron Scattering (SANS) measurements. SANS data are interpreted using both standard linear plots and the Beaucage model. The scattering intensity is dependent by alginate concentration and Ca{sup 2+} concentration. From a critical concentration of 1.0 % w/w our polymer swelled forming spherical structures with rough surfaces. Also the addition of the salt induces the collapse and the appearance of the aggregation and clusters formation.

  9. 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

  10. Investigating the Effect of Adding Drug (Lidocaine) to a Drug Delivery System Using Small-Angle X-Ray Scattering

    Science.gov (United States)

    Balogh, Joakim; Pedersen, Jan Skov

    The effect on a model drug delivery system when adding a drug, lidocaine, has been studied. Temperature and concentration dependence of a nonionic microemulsion with part of the oil, 1 and %[vol.]10, substituted with drug has been investigated. A nonionic oil-in-water microemulsion consisting of CH3(CH2)11(OCH2CH2)5OH, (C12E5), decane, water and the drug (lidocaine) that has been used to substitute part of the oil was studied. The microscopic differences have been derived from small-angle X-ray scattering (SAXS) data and the results are compared with light scattering data. Using these results together with the macroscopic differences, as observed in the phase diagram (lowering of phase boundaries), between the systems with and without lidocaine can be explained.

  11. X-ray magnetic circular dichroism and small angle neutron scattering studies of thiol capped gold nanoparticles.

    Energy Technology Data Exchange (ETDEWEB)

    de la Venta, J.; Bouzas, V.; Pucci, A.; Laguna-Marco, M. A.; Haskel, D.; te Velthuis, S. G. E; Hoffmann, A.; Lal, J.; Bleuel, M.; Ruggeri, G.; de Julian Fernandez, C.; Garcia, M. A.; Univ.Complutense de Madrid; Inst. de Magnetismo Aplicado; Univ. of Pisa; Lab. di Magnetismo Molecolare

    2009-01-01

    X-ray magnetic circular dichroism (XMCD) and Small Angle Neutron Scattering (SANS) measurements were performed on thiol capped Au nanoparticles (NPs) embedded into polyethylene. An XMCD signal of 0.8 {center_dot} 10{sup -4} was found at the Au L{sub 3} edge of thiol capped Au NPs embedded in a polyethylene matrix for which Superconducting Quantum Interference Device (SQUID) magnetometry yielded a saturation magnetization, M{sub s}, of 0.06 emu/g{sub Au}. SANS measurements showed that the 3.2 nm average-diameter nanoparticles are 28% polydispersed, but no detectable SANS magnetic signal was found with the resolution and sensitivity accessible with the neutron experiment. A comparison with previous experiments carried out on Au NPs and multilayers, yield to different values between XMCD signals and magnetization measured by SQUID magnetometer. We discuss the origin of those differences.

  12. X-ray magnetic circular dichroism and small angle neutron scattering study of thiol capped gold nanoparticles.

    Energy Technology Data Exchange (ETDEWEB)

    de la Venta, J.; Bouzas, V.; Pucci, A.; Laguna-Marco, M. A.; Haskel, D.; Pinel, E. F.; te Velthuis, S. G. E.; Hoffmann, A.; Lal, J.; Bleuel, M.; Ruggeri, G.; de Julian, C.; Garcia, M. A.; Univ. Complutense de Madrid; Inst. de Magnetismo Aplicado UCM; Univ. Pisa; Univ. di Padova

    2009-11-01

    X-ray magnetic circular dichroism (XMCD) and Small Angle Neutron Scattering (SANS) measurements were performed on thiol capped Au nanoparticles (NPs) embedded into polyethylene. An XMCD signal of 0.8 {center_dot} 10{sup -4} was found at the Au L{sub 3} edge of thiol capped Au NPs embedded in a polyethylene matrix for which Superconducting Quantum Interference Device (SQUID) magnetometry yielded a saturation magnetization, M{sub s}, of 0.06 emu/g{sub Au}. SANS measurements showed that the 3.2 nm average-diameter nanoparticles are 28% polydispersed, but no detectable SANS magnetic signal was found with the resolution and sensitivity accessible with the neutron experiment. A comparison with previous experiments carried out on Au NPs and multilayers, yield to different values between XMCD signals and magnetization measured by SQUID magnetometer. We discuss the origin of those differences.

  13. Static and quasi-elastic small angle neutron scattering on biocompatible ionic ferrofluids: magnetic and hydrodynamic interactions

    CERN Document Server

    Gazeau, F; Dubois, E; Perzynski, R

    2003-01-01

    We investigate the structure and dynamics of ionic magnetic fluids (MFs), based on ferrite nanoparticles, dispersed at pH approx 7 either in H sub 2 O or in D sub 2 O. Polarized and non-polarized static small angle neutron scattering (SANS) experiments in zero magnetic field allow us to study both the magnetic and the nuclear contributions to the neutron scattering. The magnetic interparticle attraction is probed separately from the global thermodynamic repulsion and compares well to direct magnetic susceptibility measurements. The magnetic interparticle correlation is in these fluid samples independent of the probed spatial scale. In contrast, a spatial dependence of the interparticle correlation is evidenced at large PHI by the nuclear structure factor. A model of magnetic interaction quantitatively explains the under-field anisotropy of the SANS nuclear contribution. In a quasi-elastic neutron spin-echo experiment, we probe the Brownian dynamics of translation of the nanoparticles in the range 1.3 sup<=...

  14. Effect of surfactant excess on the stability of low-polarity ferrofluids probed by small-angle neutron scattering

    Energy Technology Data Exchange (ETDEWEB)

    Petrenko, V. I., E-mail: vip@nf.jinr.ru; Avdeev, M. V. [Joint Institute for Nuclear Research (Russian Federation); Bulavin, L. A. [Taras Shevchenko National University of Kyiv (Ukraine); Almasy, L. [Hungarian Academy of Science, Wigner Research Centre for Physics (Hungary); Grigoryeva, N. A. [St. Petersburg State University (Russian Federation); Aksenov, V. L. [National Research Centre “Kurchatov Institute”, Konstantinov Petersburg Nuclear Physics Institute (Russian Federation)

    2016-01-15

    The structures of ferrofluids (FFs) based on nonpolar solvent decahydronaphthalene, stabilized by saturated monocarboxylic acids with hydrocarbon chains of different lengths, C16 (palmitic acid) and ?12 (lauric acid), with an excess of acid molecules, have been studied by small-angle neutron scattering. It is found that the addition of acid to an initially stable system with optimal composition leads to more significant structural changes (related to aggregation) than those observed previously for this class of FFs. A comparison of the influence of monocarboxylic acids on the stability of nonpolar FFs suggests that the enhancement of aggregation is much more pronounced in the case of palmitic acid excess. This fact confirms the conclusion of previous studies, according to which an increase in the hydrocarbon chain length in a saturated acid reduces the efficiency of the corresponding FF stabilization.

  15. Small angle X-ray scattering and 31P NMR studies on the phase behavior of phospholipid bilayered mixed micelles

    Science.gov (United States)

    Bolze, Jörg; Fujisawa, Tetsuro; Nagao, Takashi; Norisada, Kazushi; Saitô, Hazime; Naito, Akira

    2000-10-01

    The phase behavior of lipid bilayered micelles (`bicelles') (dimyristoyl-phosphatidylcholine, DMPC/dihexanoyl-phosphatidyl-choline, DHPC 2.6/1) has been studied by small angle X-ray scattering and 31P NMR. Below 3% w/v the bilayers are arranged in tightly packed stacks. At intermediate concentrations single units are observed, whereas at 24% w/v and higher, weak stacking occurs again. The DMPC/DHPC ratio in the bicelles strongly increases at low concentration, which is correlated with an increase in the bicelle size and stacking. The increase of the order parameter in a magnetic field is related to the stack formation. Below 297 K there is no stacking at any concentration and no magnetic alignment.

  16. Small-Angle X-ray Scattering Data in Combination with RosettaDock Improves the Docking Energy Landscape

    DEFF Research Database (Denmark)

    Sønderby, Pernille; Rinnan, Åsmund; Madsen, Jesper J.

    2017-01-01

    We have performed a benchmark to evaluate the relative success of using small-angle X-ray scattering (SAXS) data as constraints (hereafter termed SAXSconstrain) in the RosettaDock protocol (hereafter termed RosettaDockSAXS). For this purpose, we have chosen 38 protein complex structures, calculated...... the theoretical SAXS data for the protein complexes using the program CRYSOL, and then used the SAXS data as constraints. We further considered a few examples where crystal structures and experimental SAXS data are available. SAXSconstrain were added to the protocol in the initial, low-resolution docking step......-native protein complexes. The methodology used is based on rigid-body docking and works for cases where no or minor conformational changes occur upon binding of the docking partner. In a wider perspective, the strength of RosettaDockSAXS lies in the combination of low-resolution structural information on protein...

  17. A Grazing-Incidence Small-Angle X-Ray Scattering View of Vertically Aligned ZnO Nanowires

    Directory of Open Access Journals (Sweden)

    M. Lučić Lavčević

    2013-01-01

    Full Text Available We report a grazing-incidence small-angle X-ray scattering study of ZnO films with vertically aligned and randomly distributed nanowires, grown through a hydrothermal growth process on nanostructured ZnO seeding coatings and deposited by electron beam evaporation on silicon and glass, respectively. The comparison of the scattering patterns of seeding coatings and nanowires showed that the scattering of vertically aligned nanowires exhibited a specific feature: the dominant characteristic of their scattering patterns is the appearance of fine structure effects around the specular peak. These effects were clarified by the combined reflection and scattering phenomena, suggested for the aligned nanowires-substrate system. Furthermore, they enabled the calculation of the average gyration radius of nanowires in horizontal direction. The calculated value was in good agreement with the radii of nanowires estimated by surface electron microscopy. Therefore, the observed feature in the scattering pattern can serve as evidence of the aligned growth of nanowires.

  18. Structure and kinetics of chemically cross-linked protein gels from small-angle X-ray scattering

    CERN Document Server

    Kaieda, Shuji; Halle, Bertil

    2014-01-01

    Glutaraldehyde (GA) reacts with amino groups in proteins, forming intermolecular cross-links that, at sufficiently high protein concentration, can transform a protein solution into a gel. Although GA has been used as a cross-linking reagent for decades, neither the cross-linking chemistry nor the microstructure of the resulting protein gel have been clearly established. Here we use small-angle X-ray scattering (SAXS) to characterise the microstructure and structural kinetics of gels formed by cross-linking of pancreatic trypsin inhibitor, myoglobin or intestinal fatty acid-binding protein. By comparing the scattering from gels and dilute solutions, we extract the structure factor and the pair correlation function of the gel. The protein gels are spatially heterogeneous, with dense clusters linked by sparse networks. Within the clusters, adjacent protein molecules are almost in contact, but the protein concentration in the cluster is much lower than in a crystal. At the $\\sim$ 1 nm SAXS resolution, the native ...

  19. In situ probing calcium carbonate formation by combining fast controlled precipitation method and small-angle X-ray scattering.

    Science.gov (United States)

    Chao, Yanjia; Horner, Olivier; Vallée, Philippe; Meneau, Florian; Alos-Ramos, Olga; Hui, Franck; Turmine, Mireille; Perrot, Hubert; Lédion, Jean

    2014-04-01

    The initial stage of calcium carbonate nucleation and growth, found usually in "natural" precipitation conditions, is still not well understood. The calcium carbonate formation for moderate supersaturation level could be achieved by an original method called the fast controlled precipitation (FCP) method. FCP was coupled with SAXS (small-angle X-ray scattering) measurements to get insight into the nucleation and growth mechanisms of calcium carbonate particles in Ca(HCO3)2 aqueous solutions. Two size distributions of particles were observed. The particle size evolutions of these two distributions were obtained by analyzing the SAXS data. A nice agreement was obtained between the total volume fractions of CaCO3 obtained by SAXS analysis and by pH-resistivity curve modeling (from FCP tests).

  20. Power-law correlations and finite-size effects in silica particle aggregates studied by small-angle neutron scattering

    DEFF Research Database (Denmark)

    Freltoft, T.; Kjems, Jørgen; Sinha, S. K.

    1986-01-01

    Small-angle neutron scattering from normal, compressed, and water-suspended powders of aggregates of fine silica particles has been studied. The samples possessed average densities ranging from 0.008 to 0.45 g/cm3. Assuming power-law correlations between particles and a finite correlation length ξ......, the authors derive the scattering function S(q) from specific models for particle-particle correlation in these systems. S(q) was found to provide a satisfactory fit to the data for all samples studied. The fractal dimension df corresponding to the power-law correlation was 2.61±0.1 for all dry samples, and 2...

  1. 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.

  2. GaN-based vertical-cavity surface emitting lasers with sub-milliamp threshold and small divergence angle

    Science.gov (United States)

    Yeh, P. S.; Chang, C.-C.; Chen, Y.-T.; Lin, D.-W.; Liou, J.-S.; Wu, C. C.; He, J. H.; Kuo, H.-C.

    2016-12-01

    A GaN-based vertical-cavity surface emitting laser (VCSEL) structure featuring a silicon-diffusion-defined current blocking layer for lateral confinement is described. Sub-milliamp threshold currents were achieved for both 3- and 5-μm-aperture VCSELs under continuous-wave operation at room temperature. The vertical cavity was defined by a top dielectric distributed Bragg reflector (DBR) and a bottom epitaxial DBR. The emission spectrum exhibited a single peak at 411.2 nm with a linewidth of 0.4 nm and a side mode suppression ratio of more than 10 dB before device packaging. The full-width-at-half-maximum divergence angle of the 3-μm-aperture VCSEL was as small as approximately 5° which is the lowest number reported. These results implied the 3-μm-aperture VCSEL was in near single-mode operation.

  3. Atomistic modelling of scattering data in the Collaborative Computational Project for Small Angle Scattering (CCP-SAS)

    Energy Technology Data Exchange (ETDEWEB)

    Perkins, Stephen J.; Wright, David W.; Zhang, Hailiang; Brookes, Emre H.; Chen, Jianhan; Irving, Thomas C.; Krueger, Susan; Barlow, David J.; Edler, Karen J.; Scott, David J.; Terrill, Nicholas J.; King, Stephen M.; Butler, Paul D.; Curtis, Joseph E.

    2016-10-14

    The capabilities of current computer simulations provide a unique opportunity to model small-angle scattering (SAS) data at the atomistic level, and to include other structural constraints ranging from molecular and atomistic energetics to crystallography, electron microscopy and NMR. This extends the capabilities of solution scattering and provides deeper insights into the physics and chemistry of the systems studied. Realizing this potential, however, requires integrating the experimental data with a new generation of modelling software. To achieve this, the CCP-SAS collaboration (http://www.ccpsas.org/) is developing open-source, high-throughput and user-friendly software for the atomistic and coarse-grained molecular modelling of scattering data. Robust state-of-the-art molecular simulation engines and molecular dynamics and Monte Carlo force fields provide constraints to the solution structure inferred from the small-angle scattering data, which incorporates the known physical chemistry of the system. The implementation of this software suite involves a tiered approach in whichGenAppprovides the deployment infrastructure for running applications on both standard and high-performance computing hardware, andSASSIEprovides a workflow framework into which modules can be plugged to prepare structures, carry out simulations, calculate theoretical scattering data and compare results with experimental data.GenAppproduces the accessible web-based front end termedSASSIE-web, andGenAppandSASSIEalso make community SAS codes available. Applications are illustrated by case studies: (i) inter-domain flexibility in two- to six-domain proteins as exemplified by HIV-1 Gag, MASP and ubiquitin; (ii) the hinge conformation in human IgG2 and IgA1 antibodies; (iii) the complex formed between a hexameric protein Hfq and mRNA; and (iv) synthetic `bottlebrush' polymers.

  4. Asymmetric distribution of cone-shaped lipids in a highly curved bilayer revealed by a small angle neutron scattering technique

    Science.gov (United States)

    Sakuma, Y.; Urakami, N.; Taniguchi, T.; Imai, M.

    2011-07-01

    We have investigated the lipid sorting in a binary small unilamellar vesicle (SUV) composed of cone-shaped (1,2-dihexanoyl-sn-glycero-3-phosphocholine: DHPC) and cylinder-shaped (1,2-dipalmitoyl-sn-glycero-3-phosphocholine: DPPC) lipids. In order to reveal the lipid sorting we adopted a contrast matching technique of small angle neutron scattering (SANS), which extracts the distribution of deuterated lipids in the bilayer quantitatively without steric modification of lipids as in fluorescence probe techniques. First the SANS profile of protonated SUVs at a film contrast condition showed that SUVs have a spherical shape with an inner radius of 190 Å and a bilayer thickness of 40 Å. The SANS profile of deuterated SUVs at a contrast matching condition showed a characteristic scattering profile, indicating an asymmetric distribution of cone-shaped lipids in the bilayer. The characteristic profile was described well by a spherical bilayer model. The fitting revealed that most DHPC molecules are localized in the outer leaflet. Thus the shape of the lipid is strongly coupled with the membrane curvature. We compared the obtained asymmetric distribution of the cone-shaped lipids in the bilayer with the theoretical prediction based on the curvature energy model.

  5. Asymmetric distribution of cone-shaped lipids in a highly curved bilayer revealed by a small angle neutron scattering technique

    Energy Technology Data Exchange (ETDEWEB)

    Sakuma, Y; Imai, M [Department of Physics, Ochanomizu University, Bunkyo, Tokyo 112-8610 (Japan); Urakami, N [Department of Physics and Information Sciences, Yamaguchi University, Yamaguchi 753-8512 (Japan); Taniguchi, T, E-mail: imai@phys.ocha.ac.jp [Department of Chemical Engineering, Kyoto University, Kyoto 606-8510 (Japan)

    2011-07-20

    We have investigated the lipid sorting in a binary small unilamellar vesicle (SUV) composed of cone-shaped (1,2-dihexanoyl-sn-glycero-3-phosphocholine: DHPC) and cylinder-shaped (1,2-dipalmitoyl-sn-glycero-3-phosphocholine: DPPC) lipids. In order to reveal the lipid sorting we adopted a contrast matching technique of small angle neutron scattering (SANS), which extracts the distribution of deuterated lipids in the bilayer quantitatively without steric modification of lipids as in fluorescence probe techniques. First the SANS profile of protonated SUVs at a film contrast condition showed that SUVs have a spherical shape with an inner radius of 190 A and a bilayer thickness of 40 A. The SANS profile of deuterated SUVs at a contrast matching condition showed a characteristic scattering profile, indicating an asymmetric distribution of cone-shaped lipids in the bilayer. The characteristic profile was described well by a spherical bilayer model. The fitting revealed that most DHPC molecules are localized in the outer leaflet. Thus the shape of the lipid is strongly coupled with the membrane curvature. We compared the obtained asymmetric distribution of the cone-shaped lipids in the bilayer with the theoretical prediction based on the curvature energy model.

  6. Measurement of carbon condensation using small-angle x-ray scattering during detonation of the high explosive hexanitrostilbene

    Energy Technology Data Exchange (ETDEWEB)

    Bagge-Hansen, M. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Lauderbach, L. M. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Hodgin, R. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Bastea, S. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Fried, L. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Jones, A. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); van Buuren, T. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Hansen, D. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Benterou, J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); May, C. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Graber, T. [Washington State Univ., Pullman, WA (United States); Jensen, B. J. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Ilavsky, J. [Argonne National Lab. (ANL), Argonne, IL (United States); Willey, T. M. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2015-06-24

    The dynamics of carboncondensation in detonating high explosives remains controversial. Detonation model validation requires data for processes occurring at nanometer length scales on time scales ranging from nanoseconds to microseconds. A new detonation endstation has been commissioned to acquire and provide time-resolved small-angle x-ray scattering (SAXS) from detonating explosives. Hexanitrostilbene (HNS) was selected as the first to investigate due to its ease of initiation using exploding foils and flyers, vacuum compatibility, high thermal stability, and stoichiometric carbon abundance that produces high carbon condensate yields. The SAXS data during detonation, collected with 300 ns time resolution, provide unprecedented signal fidelity over a broad q-range. This fidelity permits the first analysis of both the Guinier and Porod/power-law regions of the scattering profile during detonation, which contains information about the size and morphology of the resultant carbon condensate nanoparticles. To bolster confidence in these data, the scattering angle and intensity were additionally cross-referenced with a separate, highly calibrated SAXS beamline. The data show that HNS produces carbon particles with a radius of gyration of 2.7 nm in less than 400 ns after the detonation front has passed, and this size and morphology are constant over the next several microseconds. These data directly contradict previous pioneering work on RDX/TNT mixtures and TATB, where observations indicate significant particle growth (50% or more) continues over several microseconds. As a result, the power-law slope is about –3, which is consistent with a complex disordered, irregular, or folded sp2 sub-arrangement within a relatively monodisperse structure possessing radius of gyration of 2.7 nm after the detonation of HNS.

  7. EXPRESSION, PURIFICATION, AND SMALL ANGLE X-RAY SCATTERING OF DNA REPLICATION AND REPAIR PROTEINS FROM THE HYPERTHERMOPHILE SULFOLOBUS SOLFATARICUS

    Energy Technology Data Exchange (ETDEWEB)

    Patterson, S.M.; Hatherill, J.R.; Hammel, M.; Hura, G.L.; Tainer, J.A.; Yannone, S.M.

    2008-01-01

    Vital molecular processes such as DNA replication, transcription, translation, and maintenance occur through transient protein interactions. Elucidating the mechanisms by which these protein complexes and interactions function could lead to treatments for diseases related to DNA damage and cell division control. In the recent decades since its introduction as a third domain, Archaea have shown to be simpler models for complicated eukaryotic processes such as DNA replication, repair, transcription, and translation. Sulfolobus solfataricus is one such model organism. A hyperthermophile with an optimal growth temperature of 80°C, Sulfolobus protein-protein complexes and transient protein interactions should be more stable at moderate temperatures, providing a means to isolate and study their structure and function. Here we provide the initial steps towards characterizing three DNA-related Sulfolobus proteins with small angle X-ray scattering (SAXS): Sso0257, a cell division control and origin recognition complex homolog, Sso0768, the small subunit of the replication factor C, and Sso3167, a Mut-T like protein. SAXS analysis was performed at multiple concentrations for both short and long exposure times. The Sso0257 sample was determined to be either a mixture of monomeric and dimeric states or a population of dynamic monomers in various conformational states in solution, consistent with a fl exible winged helix domain. Sso0768 was found to be a complex mixture of multimeric states in solution. Finally, molecular envelope reconstruction from SAXS data for Sso3167 revealed a novel structural component which may function as a disordered to ordered region in the presence of its substrates and/or protein partners.

  8. 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.

  9. Growth Kinetics of Lipid-Based Nanodiscs to Unilamellar Vesicles: A Time-Resolved Small Angle Neutron Scattering (SANS) Study

    Energy Technology Data Exchange (ETDEWEB)

    Mahabir, Suanne [University of Western Ontario, The; Small, Darcy [University of Western Ontario, The; Li, Ming [University of Connecticut, Storrs; Wan, Wankei [University of Western Ontario, The; Kucerka, Norbert [Canadian Neutron Beam Centre and Comelius University (Slovakia); Littrell, Ken [ORNL; Katsaras, John [ORNL; Nieh, Mu-Ping [University of Connecticut, Storrs

    2013-01-01

    Mixtures of dimyristoyl-phosphatidylcholine (DMPC), dimyristoyl-phosphatidylglycerol (DMPG) and dihexanoylphosphatidylcholine (DHPC) in aqueous solutions spontaneously form monodisperse, bilayered nanodiscs (also known as bicelles ) at or below the melting transition temperature of DMPC (TM ~23 C). In dilute systems above the main transition temperature TM of DMPC, bicelles coalesce (increasing their diameter) and eventually self-fold into unilamellar vesicles (ULVs). Time resolved small angle neutron scattering was used to study the growth kinetics of nanodiscs below and equal to TM over a period of hours as a function of temperature at two lipid concentrations in presence or absence of NaCl salt. Bicelles seem to undergo a sudden initial growth phase with increased temperature, which is then followed by a slower reaction-limited growth phase that depends on ionic strength, lipid concentration and temperature. The bicelle interaction energy was derived from the colloidal theory of Derjaguin and Landau, and Verwey and Overbeek (DLVO). While the calculated total energy between discs is attractive and proportional to their growth rate, a more detailed mechanism is proposed to describe the mechanism of disc coalescence. After annealing at low temperature (low-T), samples were heated to 50 C in order to promote the formation of ULVs. Although the low-T annealing of samples has only a marginal effect on the mean size of end-state ULVs, it does affect their polydispersity, which increases with increased T, presumably driven by the entropy of the system.

  10. From a Molecule to a Micelle: Small Angle Neutron Scattering Study of a Perfluoro Ionomer in Polar Solvents

    Science.gov (United States)

    Jiao, Xuesong; Thomas, Brian; Desmartaue, Darryl D.; Perahia, Dvora; Lal, Jyotsna

    2001-03-01

    The solution structure of perfluorosulfonimide ionomer has been investigated using small angle neutron scattering (SANS). The significance of this ionomer lies in its high potential as proton Exchange membrane for fuel cells. In polar solvents, the hydrophobicity of the fluorinated backbone drives aggregation. SANS measurements have been carried out as a function of the concentration of the ionomer, temperature as well as ionic strength. With increasing concentration, a clear transition from a molecular form factor to micellar one has been observed. Above the critical micelle concentration (CMC), SANS data revealed cylindrical aggregates. Bellow the CMC, it corresponds to a Gaussian chain. This expended configuration is intriguing since the density of the polar groups is rather low and in poor solvent one would expect a collapsed chain. The micelles were found to be extremely stable and did not brake up with increasing temperature. The radius of the micelle did not change much as a function of temperature or ionic strength. Increasing the salt concentration resulted in a significant increase in the length of the micelle. Further studies are currently underway way to discern the factors, which affect the shape and stability of these micelles.

  11. Positron Annihilation Spectroscopy and Small Angle Neutron Scattering Characterization of Nanostructural Features in Irradiated Fe-Cu-Mn Alloys

    Energy Technology Data Exchange (ETDEWEB)

    Wirth, B D; Asoka-Kumar, P; Howell, R H; Odette, G R; Sterne, P A

    2001-01-01

    Radiation embrittlement of nuclear reactor pressure vessel steels results from a high number density of nanometer sized Cu-Mn-Ni rich precipitates (CRPs) and sub-nanometer matrix features, thought to be vacancy-solute cluster complexes (VSC). However, questions exist regarding both the composition of the precipitates and the defect character and composition of the matrix features. We present results of positron annihilation spectroscopy (PAS) and small angle neutron scattering (SANS) characterization of irradiated and thermally aged Fe-Cu and Fe-Cu-Mn alloys. These complementary techniques provide insight into the composition and character of both types of nanoscale features. The SANS measurements indicate populations of CRPs and VSCs in both alloys. The CRPs are coarser in the Fe-Cu alloy and the number densities of CRP and VSC increase with the addition of Mn. The PAS involved measuring both the positron lifetimes and the Doppler broadened annihilation spectra in the high momentum region to provide elemental sensitivity at the annihilation site. The spectra in Fe-Cu-Mn specimens thermally aged to peak hardness at 450 C and irradiated at 288 C are nearly identical to elemental Cu. Positron lifetime and spectrum measurements in Fe-Cu specimens irradiated at 288 C clearly show the existence of long lifetime ({approx}500 ps) open volume defects, which also contain Cu. Thus the SANS and PAS provide a self-consistent picture of nanostructures composed of CRPs and VSCs and tend to discount high Fe concentrations in the CRPs.

  12. Nucleation and growth of gold nanoparticles studied via in situ small angle X-ray scattering at millisecond time resolution.

    Science.gov (United States)

    Polte, Jörg; Erler, Robert; Thünemann, Andreas F; Sokolov, Sergey; Ahner, T Torsten; Rademann, Klaus; Emmerling, Franziska; Kraehnert, Ralph

    2010-02-23

    Gold nanoparticles (AuNP) were prepared by the homogeneous mixing of continuous flows of an aqueous tetrachloroauric acid solution and a sodium borohydride solution applying a microstructured static mixer. The online characterization and screening of this fast process ( approximately 2 s) was enabled by coupling a micromixer operating in continuous-flow mode with a conventional in-house small angle X-ray scattering (SAXS) setup. This online characterization technique enables the time-resolved investigation of the growth process of the nanoparticles from an average radius of ca. 0.8 nm to about 2 nm. To the best of our knowledge, this is the first demonstration of a continuous-flow SAXS setup for time-resolved studies of nanoparticle formation mechanisms that does not require the use of synchrotron facilities. In combination with X-ray absorption near edge structure microscopy, scanning electron microscopy, and UV-vis spectroscopy the obtained data allow the deduction of a two-step mechanism of gold nanoparticle formation. The first step is a rapid conversion of the ionic gold precursor into metallic gold nuclei, followed by particle growth via coalescence of smaller entities. Consequently it could be shown that the studied synthesis serves as a model system for growth driven only by coalescence processes.

  13. The mechanism of eccrine sweat pore plugging by aluminium salts using microfluidics combined with small angle X-ray scattering.

    Science.gov (United States)

    Bretagne, Alice; Cotot, Franck; Arnaud-Roux, Mireille; Sztucki, Michael; Cabane, Bernard; Galey, Jean-Baptiste

    2017-05-24

    Aluminium salts are widely used to control sweating for personal hygiene purposes. Their mechanism of action as antiperspirants was previously thought to be a superficial plugging of eccrine sweat pores by the aluminium hydroxide gel. Here we present a microfluidic T junction device that mimics sweat ducts, and is designed for the real time study of interactions between sweat and ACH (Aluminium Chloro Hydrate) under conditions that lead to plug formation. We used this device to image and measure the diffusion of aluminium polycationic species in sweat counter flow. We report the results of small angle X-ray scattering experiments performed to determine the structure and composition of the plug, using BSA (Bovine Serum Albumin) as a model of sweat proteins. Our results show that pore occlusion occurs as a result of the aggregation of sweat proteins by aluminium polycations. Mapping of the device shows that this aggregation is initiated in the T junction at the location where the flow of aluminium polycations joins the flow of BSA. The mechanism involves two stages: (1) a nucleation stage in which aggregates of protein and polycations bind to the wall of the sweat duct and form a tenuous membrane, which extends across the junction; (2) a growth stage in which this membrane collects proteins that are carried by hydrodynamic flow in the sweat channel and polycations that diffuse into this channel. These results could open up perspectives to find new antiperspirant agents with an improved efficacy.

  14. Time-resolved Small Angle X-ray Scattering During the Formation of Detonation Nano-Carbon Condensates

    Science.gov (United States)

    Bagge-Hansen, Michael; Hammons, Josh; Nielsen, Mike; Lauderbach, Lisa; Hodgin, Ralph; Bastea, Sorin; van Buuren, Tony; Pagoria, Phil; May, Chadd; Jensen, Brian; Gustavsen, Rick; Watkins, Erik; Firestone, Millie; Dattelbaum, Dana; Fried, Larry; Cowan, Matt; Willey, Trevor

    2017-06-01

    Carbon nanomaterials are spontaneously generated under high pressure and temperature conditions present during the detonation of many high explosive (HE) materials. Thermochemical modeling suggests that the phase, size, and morphology of carbon condensates are strongly dependent on the type of HE used and associated evolution of temperature and pressure during the very early stages of detonation. Experimental validation of carbon condensation under these extreme conditions has been technically challenging. Here, we present synchrotron-based, time-resolved small-angle x-ray scattering (TR-SAXS) measurements collected during HE detonations, acquired from discrete sub-100 ps x-ray pulses, every 153.4 ns. We select from various HE materials and geometries to explore a range of achievable pressures and temperatures that span detonation conditions and, correspondingly, generate an array of nano-carbon products, including nano-diamonds and nano-onions. The TR-SAXS patterns evolve rapidly over the first few hundred nanoseconds. Comparing the results with modeling offers significant progress towards a general carbon equation of state. Prepared by LLNL under Contract DE-AC52-07NA27344.

  15. Cross-Validation of Data Compatibility Between Small Angle X-ray Scattering and Cryo-Electron Microscopy.

    Science.gov (United States)

    Kim, Jin Seob; Afsari, Bijan; Chirikjian, Gregory S

    2017-01-01

    Cryo-electron microscopy (EM) and small angle X-ray scattering (SAXS) are two different data acquisition modalities often used to glean information about the structure of large biomolecular complexes in their native states. A SAXS experiment is generally considered fast and easy but unveils the structure at very low resolution, whereas a cryo-EM experiment needs more extensive preparation and postacquisition computation to yield a three-dimensional (3D) density map at higher resolution. In certain applications, we may need to verify whether the data acquired in the SAXS and cryo-EM experiments correspond to the same structure (e.g., before reconstructing the 3D density map in EM). In this article, a simple and fast method is proposed to verify the compatibility of the SAXS and EM experimental data. The method is based on averaging the two-dimensional correlation of EM images and the Abel transform of the SAXS data. Orientational preferences are known to exist in cryo-EM experiments, and we also consider these effects on our method. The results are verified on simulations of conformational states of large biomolecular complexes.

  16. Structure of pure SDS and DTAB micelles in brine determined by small-angle neutron scattering (SANS)

    DEFF Research Database (Denmark)

    Bergström, M.; Pedersen, J.S.

    1999-01-01

    The geometrical structure of pure SDS and DTAB surfactant micelles in the absence of added salt as well as its dependence on the concentration of NaBr have been investigated at 40 degrees C using small-angle neutron scattering (SANS). In contrast to previous SANS measurements on the same systems we...... that ordinary surfactant micelles are shaped as circular or elongated bilayers (tablets). Both SDS and DTAB micelles appeared to be disk-like in pure D2O and the corresponding data were best fitted with a model for (monodisperse) oblate ellipsoids of revolution with half axes a=12.0 Angstrom, b=20.3 Angstrom...... ([SDS]=1.0 wt.%) and a=12.4 Angstrom, b=21.6 Angstrom ([DTAB]=1.0 wt.%). The half axis b related to the disk radius increases in both cases with an increasing amount of added salt to about 23 Angstrom (SDS) and 24 Angstrom (DTAB) at [NaBr]=0.1 M and at about [NaBr]=0.2 M the SDS micelles become tablet...

  17. A small angle X-ray scattering study of the structure and development of looseness in bovine hides and leather.

    Science.gov (United States)

    Wells, Hannah C; Holmes, Geoff; Jeng, U-Ser; Wu, Wei-Ru; Kirby, Nigel; Hawley, Adrian; Mudie, Stephen; Haverkamp, Richard G

    2017-03-01

    Some bovine hides produce poor quality leather, termed loose leather. The structural characteristics of hides and the intermediate processed stages that lead to loose leather are not well understood. In the present study, synchrotron-based small angle X-ray scattering (SAXS) is used to investigate collagen fibril orientation at the different stages of processing (i.e. from hide through to leather) that result in both tight and loose leathers. Tight leather of a relatively isotropic texture has a lower orientation index (OI) than loose leather of a more pronounced stratified texture; conversely, tight pickled hide and wet blue have a higher OI than loose pickled hide and wet blue. There is a greater increase in OI on processing from pickled hide to dry crust (leather) for loose material. This is largely the result of a greater increase in hide thickness prior to pickling for loose hide than tight hide, followed by a greater decrease at the dry crust stage. The collagen fibrils in loose leather and wet blue more readily orient under stress than do those in tight leather. Loose leather has a more pronounced layered structure than tight leather, although this difference is not apparent from SAXS measurements of hide prior to the dry crust stage; it develops during processing. The greater swelling of the loose hide during processing disrupts the structure and leads to a more layered collagen arrangement on shrinking at the final dry crust stage. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

  18. Collagen fibril alignment and deformation during tensile strain of leather: a small-angle X-ray scattering study.

    Science.gov (United States)

    Basil-Jones, Melissa M; Edmonds, Richard L; Norris, Gillian E; Haverkamp, Richard G

    2012-02-08

    The distribution and effect of applied strain on the collagen fibrils that make up leather may have an important bearing on the ultimate strength and other physical properties of the material. While sections of ovine and bovine leather were being subjected to tensile strain up to rupture, synchrotron-based small-angle X-ray scattering (SAXS) spectra were recorded edge-on to the leather at points from the corium to the grain. Measurements of both fibril orientation and collagen d spacing showed that, initially, the fibers reorient under strain, becoming more aligned. As the strain increases (5-10% strain), further fibril reorientation diminishes until, at 37% strain, the d spacing increases by up to 0.56%, indicating that significant tensile forces are being transmitted to individual fibrils. These changes, however, are not uniform through the cross-section of leather and differ between leathers of different strengths. The stresses are taken up more evenly through the leather cross-section in stronger leathers in comparison to weaker leathers, where stresses tended to be concentrated during strain. These observations contribute to our understanding of the internal strains and structural changes that take place in leather under stress.

  19. Mobile x-ray complex based on ironless pulsed betatrons. X-ray complex conception for small-angle tomography

    Science.gov (United States)

    Kozlov, S. G.; Kuropatkin, Yu P.; Nizhegorodtsev, V. I.; Savchenko, K. V.; Selemir, V. D.; Urlin, E. V.; Shamro, O. A.

    2017-05-01

    The conception of creating mobile radiographic complex based on ironless pulsed betatrons is proposed for radiography of dynamic objects having large optical thicknesses. Realization of this conception allows: a) optimizing geometry of the hydrodynamic experiment at the expense of the change of the radiation source and recorder position relatively to the test object, located in the explosion-proof chamber(EPC). Thus, it lets the intensity of the x-ray radiation be increased twice in the recorder plane as compared with available Russian complexes; b) creating an efficient environment protection system at the expense of localization of dangerous explosion products, and a shock wave connected with them; c) significantly decreasing the cost of radiographic complexes, if not building heavy protective casemates and their infrastructure. Instead of them it is possible to use cheap rapidly erected constructions. The mobile radiographic complex is described. Its characteristics, obtained during the testing powering were provided. Thickness of the lead test at 1m from the tantalum target at the limiting energy of the betatron electron beam Elim∼12 MeV( it is determined by the value of a capacitive storage of the pulsed powering system of the electromagnet) was ∼115 mm. Conception of a multibeam complex creation based on ironless pulsed betatrons for small-angle tomography was also considered.

  20. Molecular conformation of the full-length tumor suppressor NF2/Merlin—a small angle neutron scattering study

    Science.gov (United States)

    Khajeh, Jahan Ali; Ju, Jeong Ho; Atchiba, Moussoubaou; Allaire, Marc; Stanley, Christopher; Heller, William T.; Callaway, David J.E.; Bu, Zimei

    2014-01-01

    Summary The tumor suppressor protein Merlin inhibits cell proliferation upon establishing cell-cell contacts. Because Merlin has high sequence similarity to the Ezrin-Radixin-Moesin (ERM) family of proteins, the structural model of ERM protein autoinhibition and cycling between closed/resting and open/active conformational states is often employed to explain Merlin function. However, recent biochemical studies suggest alternative molecular models of Merlin function. Here, we have determined the low resolution molecular structure and binding activity of Merlin and a Merlin(S518D) mutant that mimics the inactivating phosphorylation at S518 using small angle neutron scattering (SANS) and binding experiments. SANS shows that in solution both Merlin and Merlin(S518D) adopt a closed conformation, but binding experiments indicate that a significant fraction of either Merlin or Merlin(S518D) is capable of binding to the target protein NHERF1. Upon binding to the phosphatidylinositol 4,5-bisphosphate lipid, the wild-type Merlin adopts a more open conformation than in solution, but Merlin(S518D) remains in a closed conformation. This study supports a rheostat model of Merlin in NHERF1 binding, and contributes to resolve a controversy about the molecular conformation and binding activity of Merlin. PMID:24882693

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

    Energy Technology Data Exchange (ETDEWEB)

    Quiroz, Soledad [Michigan State University, East Lansing; Sukuru, Sai Chetan K. [Michigan State University, East Lansing; Hausinger, Robert P. [Michigan State University, East Lansing; Kuhn, Leslie A. [Michigan State University, East Lansing; Heller, William T [ORNL

    2008-01-01

    Conformational changes of Klebsiella aerogenes urease apoprotein (UreABC){sub 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){sub 3}, and (UreABC-UreDF){sub 3} confirm that UreD and UreF bind near UreB at the periphery of the (UreAC){sub 3} structure. This study supports an activation model in which a domain-shifted UreB conformation in (UreABC-UreDF){sub 3} allows CO{sub 2} and nickel ions to gain access to the nascent active site.

  2. Thorough small-angle X-ray scattering analysis of the instability of liquid micro-jets in air.

    Science.gov (United States)

    Marmiroli, Benedetta; Cacho-Nerin, Fernando; Sartori, Barbara; Pérez, Javier; Amenitsch, Heinz

    2014-01-01

    Liquid jets are of interest, both for their industrial relevance and for scientific applications (more important, in particular for X-rays, after the advent of free-electron lasers that require liquid jets as sample carrier). Instability mechanisms have been described theoretically and by numerical simulation, but confirmed by few experimental techniques. In fact, these are mainly based on cameras, which is limited by the imaging resolution, and on light scattering, which is hindered by absorption, reflection, Mie scattering and multiple scattering due to complex air/liquid interfaces during jet break-up. In this communication it is demonstrated that synchrotron small-angle X-ray scattering (SAXS) can give quantitative information on liquid jet dynamics at the nanoscale, by detecting time-dependent morphology and break-up length. Jets ejected from circular tubes of different diameters (100-450 µm) and speeds (0.7-21 m s(-1)) have been explored to cover the Rayleigh and first wind-induced regimes. Various solvents (water, ethanol, 2-propanol) and their mixtures have been examined. The determination of the liquid jet behaviour becomes essential, as it provides background data in subsequent studies of chemical and biological reactions using SAXS or X-ray diffraction based on synchrotron radiation and free-electron lasers.

  3. Combined small angle X-ray solution scattering with atomic force microscopy for characterizing radiation damage on biological macromolecules.

    Science.gov (United States)

    Costa, Luca; Andriatis, Alexander; Brennich, Martha; Teulon, Jean-Marie; Chen, Shu-Wen W; Pellequer, Jean-Luc; Round, Adam

    2016-10-27

    Synchrotron radiation facilities are pillars of modern structural biology. Small-Angle X-ray scattering performed at synchrotron sources is often used to characterize the shape of biological macromolecules. A major challenge with high-energy X-ray beam on such macromolecules is the perturbation of sample due to radiation damage. By employing atomic force microscopy, another common technique to determine the shape of biological macromolecules when deposited on flat substrates, we present a protocol to evaluate and characterize consequences of radiation damage. It requires the acquisition of images of irradiated samples at the single molecule level in a timely manner while using minimal amounts of protein. The protocol has been tested on two different molecular systems: a large globular tetremeric enzyme (β-Amylase) and a rod-shape plant virus (tobacco mosaic virus). Radiation damage on the globular enzyme leads to an apparent increase in molecular sizes whereas the effect on the long virus is a breakage into smaller pieces resulting in a decrease of the average long-axis radius. These results show that radiation damage can appear in different forms and strongly support the need to check the effect of radiation damage at synchrotron sources using the presented protocol.

  4. Mesostructure anisotropy of bacterial cellulose-polyacrylamide hydrogels as studied by spin-echo small-angle neutron scattering

    CERN Document Server

    Velichko, E V; Chetverikov, Yu O; Duif, C P; Bouwman, W G; Smyslov, R Yu

    2016-01-01

    The submicron- and micron-scale structures of composite hydrogels based on bacterial cellulose (BC) and polyacrylamide were studied by spin-echo small-angle neutron scattering (SESANS). These hydrogels were synthesized via free-radical polymerization of acrylamide carried out in pellicle of BC swollen in the reaction solution. No neutron scattering was observed for the samples swollen in heavy water to the equilibrium state, but a SESANS signal appeared when TbCl$_{3}$ salt was added to the solvent. The SESANS dependences obtained for these samples revealed the anisotropy of mesostructure for the hydrogels under investigation. Density inhomogeneities on the characteristic scale of 11.5 $\\pm$ 0.5 $\\mu$m were detected in one specific orientation of the sample, i.e. with growth plane of BC parallel to plane formed by neutron beam and spin-echo length. The uniaxial anisotropy revealed agrees with the proposed model, which attributes this behavior to the existence of the tunnel-like oriented structures inside BC.

  5. A small-angle neutron scattering study of sodium dodecyl sulfate-poly(propylene oxide) methacrylate mixed micelles.

    Science.gov (United States)

    Bastiat, Guillaume; Grassl, Bruno; Borisov, Oleg; Lapp, Alain; François, Jeanne

    2006-03-15

    Mixed micelle of protonated or deuterated sodium dodecyl sulfate (SDS and SDSd25, respectively) and poly(propylene oxide) methacrylate (PPOMA) are studied by small-angle neutron scattering (SANS). In all the cases the scattering curves exhibit a peak whose position changes with the composition of the system. The main parameters which characterize mixed micelles, i.e., aggregation numbers of SDS and PPOMA, geometrical dimensions of the micelles and degree of ionisation are evaluated from the analysis of the SANS curves. The position q(max) of the correlation peak can be related to the average aggregation numbers of SDS-PPOMA and SDSd25-PPOMA mixed micelles. It is found that the aggregation number of SDS decreases upon increasing the weight ratio PPOMA/SDS (or SDSd25). The isotopic combination, which uses the "contrast effect" between the two micellar systems, has allowed us to determine the mixed micelle composition. Finally, the SANS curves were adjusted using the RMSA for the structure factor S(q) of charged spherical particles and the form factor P(q) of spherical core-shell particle. This analysis confirms the particular core-shell structure of the SDS-PPOMA mixed micelle, i.e., a SDS "core" micelle surrounded by the shell formed by PPOMA macromonomers. The structural parameters of mixed micelles obtained from the analysis of the SANS data are in good agreement with those determined previously by conductimetry and fluorescence studies.

  6. Intrinsic flexibility of West Nile virus protease in solution characterized using small-angle X-ray scattering.

    Science.gov (United States)

    Garces, Andrea P; Watowich, Stanley J

    2013-10-01

    West Nile virus (WNV) is a mosquito-borne flavivirus with a rapidly expanding global distribution. Infection can cause severe neurological disease and fatality in humans. Efforts are ongoing to develop antiviral drugs that inhibit the WNV protease, a viral enzyme required for polyprotein processing. Unfortunately, little is known about the solution structure of recombinant WNV protease (NS2B-NS3pro) used for antiviral drug discovery and development, although X-ray crystal structures and nuclear magnetic resonance (NMR) studies have provided valuable insights into the interactions between NS2B-NS3pro and peptide-based inhibitors. We completed small-angle X-ray scattering and Fourier transform infrared spectroscopy experiments to determine the solution structure and dynamics of WNV NS2B-NS3pro in the absence of a bound substrate or inhibitor. Importantly, these solution studies suggested that all or most of the NS2B cofactor was highly flexible and formed an ensemble of structures, in contrast to the NS2B tertiary structures observed in crystallographic and NMR studies. The secondary structure of NS2B-NS3pro in solution had high β-content, similar to the secondary structure observed in crystallographic studies. This work provided evidence of the intrinsic flexibility and conformational heterogeneity of the NS2B chain of the WNV protease in the absence of substratelike ligands, which should be considered during antiviral drug discovery and development efforts.

  7. Recent developments and ASAXS measurements at the ultra small angle X-ray scattering instrument of HASYLAB

    CERN Document Server

    Krosigk, G V; Gehrke, R; Kranold, R

    2001-01-01

    The wiggler beamline BW4 at the synchrotron radiation facility HASYLAB (DESY) is mainly designed for Ultra Small Angle X-ray Scattering (USAXS) and usually operated with detector-sample distances up to 13 m and at photon energies between 4 and 16 keV. With a new optical design the largest observable correlation distances have now been increased up to 9x10 sup 3 A. A grazing incidence set-up [P. Mueller-Buschbaum et al., Europhys. Lett. 42 (5) (1998) 517], vapor chamber, furnace, tensile testing machine and other instruments make the USAXS beamline attractive for a variety of scattering experiments [A. Endres et al., Rev. Sci. Instrum. 11 (1997) 68; A. Karl et al., J. Macromolecular Sci.-Phys. B 38 (5 and 6) (1999) 901; S. Minko et al., J. Macromolecular Sci., Phys. B 38 (5 and 6) (1999) 913]. A fully evacuated beampath allows high quality measurements with very low background signal. A photodiode mounted in the primary beam stop registers the primary beam flux simultaneously to the data acquisition and thus p...

  8. Assessment of critical dimension small-angle x-ray scattering measurement approaches for FinFET fabrication process monitoring

    Science.gov (United States)

    Settens, Charles; Cordes, Aaron; Bunday, Benjamin; Bello, Abner; Kamineni, Vimal; Paul, Abhijeet; Fronheiser, Jody; Matyi, Richard

    2014-10-01

    We have used synchrotron-based critical dimension small-angle x-ray scattering (CD-SAXS) to monitor the impact of hydrogen annealing on the structural characteristics of silicon FinFET structures fabricated using self-aligned double patterning on both bulk silicon and silicon-on-insulator (SOI) substrates. H2 annealing under different conditions of temperature and gas pressure allowed us to vary the sidewall roughness and observe the response in the two metrology approaches. In the case of the simpler bulk Si FinFET structures, the CD-SAXS measurements of the critical dimensions are in substantive agreement with the top-down critical dimension scanning electron microscopy metrology. Corresponding characterizations on SOI-based FinFET structures showed less agreement, which is attributed to the more complex structural model required for SOI FinFET CD-SAXS modeling. Because sidewall roughness is an important factor in the performance characteristics of Si FinFETs, we have compared the results of roughness measurements using both critical dimension atomic force microscopy (CD-AFM) and CD-SAXS. The measurements yield similar estimates of sidewall roughness, although the CD-AFM values were typically larger than those generated by CD-SAXS. The reasons for these differences will be discussed.

  9. Small angle neutron scattering study of sodium dodecyl sulfate micellar growth driven by addition of a hydrotropic salt.

    Science.gov (United States)

    Hassan, P A; Fritz, Gerhard; Kaler, Eric W

    2003-01-01

    The structures of aggregates formed in aqueous solutions of an anionic surfactant, sodium dodecyl sulfate (SDS), with the addition of a cationic hydrotropic salt, p-toluidine hydrochloride (PTHC), have been investigated by small angle neutron scattering (SANS). The SANS spectra exhibit a pronounced peak at low salt concentration, indicating the presence of repulsive intermicellar interactions. Model-independent real space information about the structure is obtained from a generalized indirect Fourier transformation (GIFT) technique in combination with a suitable model for the interparticle structure factor. The interparticle interaction is captured using the rescaled mean spherical approximation (RMSA) closure relation and a Yukawa form of the interaction potential. Further quantification of the geometrical parameters of the micelles was achieved by a complete fit of the SANS data using a prolate ellipsoidal form factor and the RMSA structure factor. The present study shows that PTHC induces a decrease in the fractional charge of the micelles due to adsorption at the micellar surface and consequent growth of the SDS micelles from nearly globular to rodlike as the concentration of PTHC increases.

  10. Temperature Assisted in-Situ Small Angle X-ray Scattering Analysis of Ph-POSS/PC Polymer Nanocomposite

    Science.gov (United States)

    Yadav, Ramdayal; Naebe, Minoo; Wang, Xungai; Kandasubramanian, Balasubramanian

    2016-07-01

    Inorganic/organic nanofillers have been extensively exploited to impart thermal stability to polymer nanocomposite via various strategies that can endure structural changes when exposed a wide range of thermal environment during their application. In this abstraction, we have utilized temperature assisted in-situ small angle X-ray scattering (SAXS) to examine the structural orientation distribution of inorganic/organic nanofiller octa phenyl substituted polyhedral oligomeric silsesquioxane (Ph-POSS) in Polycarbonate (PC) matrix from ambient temperature to 180 °C. A constant interval of 30 °C with the heating rate of 3 °C/min was utilized to guise the temperature below and above the glass transition temperature of PC followed by thermal gravimetric, HRTEM, FESEM and hydrophobic analysis at ambient temperature. The HRTEM images of Ph-POSS nano unit demonstrated hyperrectangular structure, while FESEM image of the developed nano composite rendered separated phase containing flocculated and overlapped stacking of POSS units in the PC matrix. The phase separation in polymer nanocomposite was further substantiated by thermodynamic interaction parameter (χ) and mixing energy (Emix) gleaned via Accelrys Materials studio. The SAXS spectra has demonstrated duplex peak at higher scattering vector region, postulated as a primary and secondary segregated POSS domain and followed by abundance of secondary peak with temperature augmentation.

  11. ATSAS 2.8: a comprehensive data analysis suite for small-angle scattering from macromolecular solutions.

    Science.gov (United States)

    Franke, D; Petoukhov, M V; Konarev, P V; Panjkovich, A; Tuukkanen, A; Mertens, H D T; Kikhney, A G; Hajizadeh, N R; Franklin, J M; Jeffries, C M; Svergun, D I

    2017-08-01

    ATSAS is a comprehensive software suite for the analysis of small-angle scattering data from dilute solutions of biological macromolecules or nanoparticles. It contains applications for primary data processing and assessment, ab initio bead modelling, and model validation, as well as methods for the analysis of flexibility and mixtures. In addition, approaches are supported that utilize information from X-ray crystallography, nuclear magnetic resonance spectroscopy or atomistic homology modelling to construct hybrid models based on the scattering data. This article summarizes the progress made during the 2.5-2.8 ATSAS release series and highlights the latest developments. These include AMBIMETER, an assessment of the reconstruction ambiguity of experimental data; DATCLASS, a multiclass shape classification based on experimental data; SASRES, for estimating the resolution of ab initio model reconstructions; CHROMIXS, a convenient interface to analyse in-line size exclusion chromatography data; SHANUM, to evaluate the useful angular range in measured data; SREFLEX, to refine available high-resolution models using normal mode analysis; SUPALM for a rapid superposition of low- and high-resolution models; and SASPy, the ATSAS plugin for interactive modelling in PyMOL. All these features and other improvements are included in the ATSAS release 2.8, freely available for academic users from https://www.embl-hamburg.de/biosaxs/software.html.

  12. Nano-Structural Investigation on Cellulose Highly Dissolved in Ionic Liquid: A Small Angle X-ray Scattering Study.

    Science.gov (United States)

    Endo, Takatsugu; Hosomi, Shota; Fujii, Shunsuke; Ninomiya, Kazuaki; Takahashi, Kenji

    2017-01-21

    We investigated nano-structural changes of cellulose dissolved in 1-ethyl-3-methylimidazolium acetate-an ionic liquid (IL)-using a small angle X-ray scattering (SAXS) technique over the entire concentration range (0-100 mol %). Fibril structures of cellulose disappeared at 40 mol % of cellulose, which is a significantly higher concentration than the maximum concentration of dissolution (24-28 mol %) previously determined in this IL. This behavior is explained by the presence of the anion bridging, whereby an anion prefers to interact with multiple OH groups of different cellulose molecules at high concentrations, discovered in our recent work. Furthermore, we observed the emergence of two aggregated nano-structures in the concentration range of 30-80 mol %. The diameter of one structure was 12-20 nm, dependent on concentration, which is ascribed to cellulose chain entanglement. In contrast, the other with 4.1 nm diameter exhibited concentration independence and is reminiscent of a cellulose microfibril, reflecting the occurrence of nanofibrillation. These results contribute to an understanding of the dissolution mechanism of cellulose in ILs. Finally, we unexpectedly proposed a novel cellulose/IL composite: the cellulose/IL mixtures of 30-50 mol % that possess liquid crystallinity are sufficiently hard to be moldable.

  13. Molecular Structures of Fluid Phase Phosphatidylglycerol Bilayers as Determined by Small Angle Neutron and X-ray Scattering

    Energy Technology Data Exchange (ETDEWEB)

    Pan, Jianjun [ORNL; Heberle, Frederick A [ORNL; Tristram-Nagle, Dr. Stephanie [Carnegie Mellon University; Michelle, Szymanski [Rutgers University; Mary, Koepfinger [Rutgers University; Katsaras, John [ORNL; Kucerka, Norbert [Canadian Neutron Beam Centre and Comelius University (Slovakia)

    2012-01-01

    We have determined the molecular structures of commonly used phosphatidylglycerols (PGs) in the commonly accepted biologically relevant fluid phase. This was done by simultaneously analyzing small-angle neutron and X-ray scattering data, with the constraint of a measured volume per lipid. We report the temperature dependence of bilayer parameters obtained using the one dimensional scattering density profile model derived from molecular dynamics simulations, including the area per lipid, the overall bilayer thickness, as well as other intrabilayer parameters (e.g., hydrocarbon thickness). Lipid areas are found to be larger than their phosphatidylcholine (PC) counterparts, a result likely due to repulsive electrostatic interactions taking place between the charged PG headgroups even in the presence of Na+ counterions. In general, PG and PC bilayers show a similar response to changes in temperature and chain length, but differ in their response to chain unsaturation. For example, compared to their PC counterparts, the inclusion of a double bond in PG lipids results in a smaller incremental change in lipid area and bilayer thickness. However, the extrapolated lipid area of saturated PG lipids at infinite chain length is found to be similar to that of PCs, an indication of the glycerol-carbonyl backbone's pivotal role in influencing the lipid-water interface.

  14. Nano-Structural Investigation on Cellulose Highly Dissolved in Ionic Liquid: A Small Angle X-ray Scattering Study

    Directory of Open Access Journals (Sweden)

    Takatsugu Endo

    2017-01-01

    Full Text Available We investigated nano-structural changes of cellulose dissolved in 1-ethyl-3-methylimidazolium acetate—an ionic liquid (IL—using a small angle X-ray scattering (SAXS technique over the entire concentration range (0–100 mol %. Fibril structures of cellulose disappeared at 40 mol % of cellulose, which is a significantly higher concentration than the maximum concentration of dissolution (24–28 mol % previously determined in this IL. This behavior is explained by the presence of the anion bridging, whereby an anion prefers to interact with multiple OH groups of different cellulose molecules at high concentrations, discovered in our recent work. Furthermore, we observed the emergence of two aggregated nano-structures in the concentration range of 30–80 mol %. The diameter of one structure was 12–20 nm, dependent on concentration, which is ascribed to cellulose chain entanglement. In contrast, the other with 4.1 nm diameter exhibited concentration independence and is reminiscent of a cellulose microfibril, reflecting the occurrence of nanofibrillation. These results contribute to an understanding of the dissolution mechanism of cellulose in ILs. Finally, we unexpectedly proposed a novel cellulose/IL composite: the cellulose/IL mixtures of 30–50 mol % that possess liquid crystallinity are sufficiently hard to be moldable.

  15. A small-angle X-ray scattering study of the lyotropic nematic phase of vanadium pentoxide gels

    Energy Technology Data Exchange (ETDEWEB)

    Davidson, P. [Universite de Paris-Sud, Orsay (France). Lab. de Phys. des Solides; Bourgaux, C.; Sergot, P.; Livage, J.

    1997-10-01

    Aqueous suspensions of vanadium pentoxide (V{sub 2}O{sub 5}) ribbons, also called Zocher phases, are known to display a lyotropic nematic phase. In this paper, it is shown how the small-angle X-ray scattering (SAXS) technique can provide useful information on the building blocks and their organization in this phase. SAXS experiments were performed either on unoriented samples or on samples aligned by a magnetic field or by shear flow. The scattering is comparable to that of the other classic lyotropic nematic phases displayed by stiff organic rod-like particles such as the tobacco mosaic virus. Scattering studies show that the building blocks have a ribbon shape, that their thickness is 9(1) A and indirectly that their width is several 100 A. Their length is known to be around a few thousand A and therefore could not be measured by SAXS. By following the average distance between the ribbons as a function of concentration, it is shown that the swelling of the phase is one-dimensional at large concentrations and two-dimensional at low concentrations. Finally, estimates of the nematic order parameter of a single domain sample and of samples sheared in a Couette cell have been obtained. (orig.). 24 refs.

  16. Human serum albumin interactions with C60 fullerene studied by spectroscopy, small-angle neutron scattering, and molecular dynamics simulations

    Science.gov (United States)

    Li, Song; Zhao, Xiongce; Mo, Yiming; Cummings, Peter T.; Heller, William T.

    2013-07-01

    Concern about the toxicity of engineered nanoparticles, such as the prototypical nanomaterial C60 fullerene, continues to grow. While, evidence continues to mount that C60 and its derivatives may pose health hazards, the specific molecular interactions of these particles with biological macromolecules require further investigation. In this article, we report combined experimental and theoretical studies on the interaction of one of the most prevalent proteins in the human body, human serum albumin (HSA), with C60 in an aqueous environment. The C60-HSA interaction was probed by circular dichroism (CD) spectroscopy, small-angle neutron scattering (SANS), and atomistic molecular dynamics (MD) simulations to understand C60-driven changes in the structure of HSA in solution. The CD spectroscopy demonstrates that the secondary structure of the protein decreases in α-helical content in response to the presence of C60 (0.68 nm in diameter). Similarly, C60 produces subtle changes in the solution conformation of HSA (an 8.0 nm × 3.8 nm protein), as evidenced by the SANS data and MD simulations, but the data do not indicate that C60 changes the oligomerization state of the protein, such as by inducing aggregation. The results demonstrate that the interaction is not highly disruptive to the protein in a manner that would prevent it from performing its physiological function.

  17. Magnetic small-angle neutron scattering on bulk metallic glasses: A feasibility study for imaging displacement fields

    Science.gov (United States)

    Mettus, Denis; Deckarm, Michael; Leibner, Andreas; Birringer, Rainer; Stolpe, Moritz; Busch, Ralf; Honecker, Dirk; Kohlbrecher, Joachim; Hautle, Patrick; Niketic, Nemanja; Fernández, Jesús Rodríguez; Barquín, Luis Fernández; Michels, Andreas

    2017-12-01

    Magnetic-field-dependent small-angle neutron scattering (SANS) has been utilized to study the magnetic microstructure of bulk metallic glasses (BMGs). In particular, the magnetic scattering from soft magnetic Fe70Mo5Ni5P12.5B2.5C5 and hard magnetic (Nd60Fe30Al10) 92Ni8 alloys in the as-prepared, aged, and mechanically deformed state is compared. While the soft magnetic BMGs exhibit a large field-dependent SANS response with perturbations originating predominantly from spatially varying magnetic anisotropy fields, the SANS cross sections of the hard magnetic BMGs are only weakly dependent on the field, and their angular anisotropy indicates the presence of scattering contributions due to spatially dependent saturation magnetization. Moreover, we observe an unusual increase in the magnetization of the rare-earth-based alloy after deformation. Analysis of the SANS cross sections in terms of the correlation function of the spin misalignment reveals the existence of field-dependent anisotropic long-wavelength magnetization fluctuations on a scale of a few tens of nanometers. We also give a detailed account of how the SANS technique relates to unraveling displacement fields on a mesoscopic length scale in disordered magnetic materials.

  18. First results in rapid MR imaging of focal liver and spleen lesions using field echos and small angle excitation (gradient echo sequences)

    Energy Technology Data Exchange (ETDEWEB)

    Griebel, J.; Hess, C.F.; Kurtz, B.; Klose, U.; Kueper, K.

    1987-01-01

    15 healthy subjects and 39 patients with focal liver and spleen lesions were examined via MR tomography at 1.5 tesla. Gradient field echos at small angle excitation (< 90/sup 0/) were employed. The imaging time per layer was 10 seconds so that rapid imaging could be carried out at respiratory standstill. This enabled visualisation of liver and spleen without interference by breathing artifacts and with accurate localisation. Focal lesions can be imaged best at low flip-angle pulses (liver) or low to medium-angle pulses (spleen). The primary liver cell carcinoma is visualised as an inhomogeneous structure with similar signal intensity as the surrounding tissue. All other examined liver lesions (metastases, haemangiomas, lymphatic infiltrates, echinococcus cysts, FNH, gummae) showed greater signal intensity than the remaining organ at small angle excitation. Furthermore, contrast reversals were seen at medium-angle pulses. Contrariwise, with the exception of the light-coloured spleen infarcts, spleen lesions (lymphatic infiltrate, Boeck's disease or sarcoidosis) appeared darker at all excitation angles than the surrounding tissue.

  19. In situ determination of aging precipitation in deformed Fe-Cu and Fe-Cu-B-N alloys by time-resolved small-angle neutron scattering

    NARCIS (Netherlands)

    He, S.M.; Van Dijk, N.H.; Paladugu, M.; Schut, H.; Kohlbrecher, J.; Tichelaar, F.D.; Van der Zwaag, S.

    2010-01-01

    We performed in situ time-resolved small-angle neutron scattering (SANS) measurements on high-purity Fe-Cu and Fe-Cu-B-N alloys during isothermal aging at 550 °C in order to study the potential self-healing of deformation-induced defects by nanosized Cu precipitation. Three different samples with

  20. Inner Stucture of Thin Films of Lamellar Poly(styrene-b-butadiene) Diblock Copolymers as revealed by Grazing-Incidence Small-Angle Scattering

    DEFF Research Database (Denmark)

    Busch, Peter; Posselt, Dorthe; Smilgies, Detlef-Matthias

    2007-01-01

    The lamellar orientation in supported, thin films of poly(styrene-b-butadiene) (P(S-b-B)) depends on block copolymer molar mass. We have studied films from nine block copolymer samples with molar masses between 13.9 and 183 kg/mol using grazing-incidence small-angle X-ray scattering (GISAXS) and ...

  1. Structural Properties of Bulk and Aqueous Systems of PEO-PIB-PEO Triblock Copolymers as Studied by Small-Angle Neutron Scattering and Cryo-Transmission Electron Microscopy

    DEFF Research Database (Denmark)

    Mortensen, Kell; Talmon, Yeshayahu; Gao, Bo

    1997-01-01

    The phase behavior of a low molecular weight (M-w = 6000) symmetric triblock copolymer of poly(ethylene oxide) and poly(isobutylene), PEO-PIB-PEO, in the bulk as well in aqueous, D2O, solutions has been studied using small-angle neutron scattering and cryo-transmission electron microscopy...

  2. Grazing-incidence small-angle X-ray scattering from thin polymer films with lamellar structures - the scattering cross section in the distorted-wave Born approximation

    DEFF Research Database (Denmark)

    Posselt, Dorthe; Busch, Peter; Rauscher, Markus

    2006-01-01

    Grazing-incidence small-angle X-ray or neutron scattering of thin polymer films reveals information about the ordering and preferential orientations of the phase-separated microdomains within the films. The grazing-incidence geometry enhances the surface sensitivity; however, the scattering has t...

  3. Structure of immune stimulating complex matrices and immune stimulating complexes in suspension determined by small-angle X-ray scattering

    DEFF Research Database (Denmark)

    Pedersen, J.S.; Oliveira, C.L.P.; Hübschmann, Henriette Baun

    2012-01-01

    Immune stimulating complex (ISCOM) particles consisting of a mixture of Quil-A, cholesterol, and phospholipids were structurally characterized by small-angle x-ray scattering (SAXS). The ISCOM particles are perforated vesicles of very well-defined structures. We developed and implemented a novel ...

  4. A small-angle neutron scattering study of the structure of graphitized carbon black aggregates in Triton X-100/water solutions

    DEFF Research Database (Denmark)

    Garamus, V.M.; Pedersen, J.S.

    1998-01-01

    The structure of graphitized carbon black (CB) aggregates dispersed in water solutions with a non-ionic surfactant are studied by small-angle neutron scattering using contrast variation by heavy/light water mixing. The addition of CB to Triton X-100/water mixtures shifts the critical micelle...

  5. Study of change in dispersion and orientation of clay platelets in a polymer nanocomposite during tensile test by variostage small-angle X-ray scattering

    CSIR Research Space (South Africa)

    Bandyopadhyay, J

    2012-04-01

    Full Text Available To understand the change in dispersion and orientation of clay platelets in three-dimensional space during tensile test, neat polymer and its nanocomposite samples were studied by small- and wide-angle X-ray scattering (SWAXS). The samples after...

  6. Small-angle X-ray scattering studies of metastable intermediates of beta-lactoglobulin isolated after heat-induced aggregation

    DEFF Research Database (Denmark)

    Carrotta, R.; Arleth, L.; Pedersen, J.S.

    2003-01-01

    Small-angle x-ray scattering was used for studying intermediate species, isolated after heat-induced aggregation of the A variant of bovine P-lactoglobulin. The intermediates were separated in two fractions, the heated metastable dimer and heated metastable oligomers larger than the dimer. The pa...

  7. Nanostructured surfactant-based systems for the removal of polymers from wall paintings: a small-angle neutron scattering study.

    Science.gov (United States)

    Baglioni, Michele; Berti, Debora; Teixeira, José; Giorgi, Rodorico; Baglioni, Piero

    2012-10-30

    Nanostructured soft matter systems represent effective and long-lasting solutions with respect to traditional and often obsolete methodologies for the conservation of works of art. In particular, complex fluids such as micelles and microemulsions are the most performing media for the removal of organic materials from porous supports, like wall paintings or stones. In this Article, we report on the characterization of two systems, EAPC and XYL, which have shown good to optimal performances in the removal of organic polymers from wall paintings. EAPC is a five-components fluid composed of water, sodium dodecylsulfate (SDS), 1-pentanol (PeOH), propylene carbonate (PC), and ethyl acetate (EA), while XYL is a "classical" o/w microemulsion, where p-xylene droplets are stabilized in water by SDS and PeOH. Small-angle neutron scattering (SANS) with contrast variation is used to infer a detailed picture of the structure of these complex fluids, with a particular focus on the partition of the components between the bulk phase and the nanocompartments. We found that, differently from XYL, the EAPC system is neither a microemulsion nor a simple micellar solution, with the cosolvents partitioned between the dispersing phase and the disperse droplets. These different structural features play a key role in defining the cleaning effectiveness and specifically the kinetics of interaction between the nanofluid and the polymeric coating to be removed, which is of paramount importance for the application in the field. Both of these nanofluids are effective in polymer removal, but EAPC is considerably more efficient and versatile. The composition and the structure at the nanoscale determine the capability of removing a broad range of different polymer coatings from porous materials. A representative case study is here described, addressing a particularly challenging conservative issue, which is the removal of a multilayered aged coating that was irreversibly damaging the pictorial

  8. Dielectric RheoSANS - Simultaneous Interrogation of Impedance, Rheology and Small Angle Neutron Scattering of Complex Fluids.

    Science.gov (United States)

    Richards, Jeffrey J; Gagnon, Cedric V L; Krzywon, Jeffery R; Wagner, Norman J; Butler, Paul D

    2017-04-10

    A procedure for the operation of a new dielectric RheoSANS instrument capable of simultaneous interrogation of the electrical, mechanical and microstructural properties of complex fluids is presented. The instrument consists of a Couette geometry contained within a modified forced convection oven mounted on a commercial rheometer. This instrument is available for use on the small angle neutron scattering (SANS) beamlines at the National Institute of Standards and Technology (NIST) Center for Neutron Research (NCNR). The Couette geometry is machined to be transparent to neutrons and provides for measurement of the electrical properties and microstructural properties of a sample confined between titanium cylinders while the sample undergoes arbitrary deformation. Synchronization of these measurements is enabled through the use of a customizable program that monitors and controls the execution of predetermined experimental protocols. Described here is a protocol to perform a flow sweep experiment where the shear rate is logarithmically stepped from a maximum value to a minimum value holding at each step for a specified period of time while frequency dependent dielectric measurements are made. Representative results are shown from a sample consisting of a gel composed of carbon black aggregates dispersed in propylene carbonate. As the gel undergoes steady shear, the carbon black network is mechanically deformed, which causes an initial decrease in conductivity associated with the breaking of bonds comprising the carbon black network. However, at higher shear rates, the conductivity recovers associated with the onset of shear thickening. Overall, these results demonstrate the utility of the simultaneous measurement of the rheo-electro-microstructural properties of these suspensions using the dielectric RheoSANS geometry.

  9. Integration of Small Angle X-Ray Scattering Data Into Structural Modeling of Proteins And Their Assemblies

    Energy Technology Data Exchange (ETDEWEB)

    Forster, F.; Webb, B.; Krukenberg, K.A.; Tsuruta, H.; Agard, D.A.; Sali, A.

    2009-05-18

    A major challenge in structural biology is to determine the configuration of domains and proteins in multidomain proteins and assemblies, respectively. All available data should be considered to maximize the accuracy and precision of these models. Small-angle X-ray scattering (SAXS) efficiently provides low-resolution experimental data about the shapes of proteins and their assemblies. Thus, we integrated SAXS profiles into our software for modeling proteins and their assemblies by satisfaction of spatial restraints. Specifically, we modeled the quaternary structures of multidomain proteins with structurally defined rigid domains as well as quaternary structures of binary complexes of structurally defined rigid proteins. In addition to SAXS profiles and the component structures, we used stereochemical restraints and an atomic distance-dependent statistical potential. The scoring function is optimized by a biased Monte Carlo protocol, including quasi-Newton and simulated annealing schemes. The final prediction corresponds to the best scoring solution in the largest cluster of many independently calculated solutions. To quantify how well the quaternary structures are determined based on their SAXS profiles, we used a benchmark of 12 simulated examples as well as an experimental SAXS profile of the homotetramer D-xylose isomerase. Optimization of the SAXS-dependent scoring function generally results in accurate models if sufficiently precise approximations for the constituent rigid bodies are available; otherwise, the best scoring models can have significant errors. Thus, SAXS profiles can play a useful role in the structural characterization of proteins and assemblies if they are combined with additional data and used judiciously. Our integration of a SAXS profile into modeling by satisfaction of spatial restraints will facilitate further integration of different kinds of data for structure determination of proteins and their assemblies.

  10. The effect of small angle of attack on the laminar-turbulent transition in boundary layer on swept wing at Mach number M=2

    Science.gov (United States)

    Semionov, N. V.; Yermolaev, Yu. G.; Kosinov, A. D.; Semenov, A. N.; Smorodsky, B. V.; Yatskikh, A. A.

    2017-10-01

    The paper is devoted to an experimental and theoretical study of effect of small angle of attack on disturbances evolution and laminar-turbulent transition in a supersonic boundary layer on swept wing at Mach number M=2. The experiments are conducted at the low nose supersonic wind tunnel T-325 of ITAM. Model is a symmetrical wing with a 45° sweep angle, a 3 percent-thick circular-arc airfoil. The transition location is determined using a hot-wire anemometer. Confirmed monotonous growth of the transition Reynolds numbers with increasing of angle of attack from -2° to 2.5°. The experimental data on the influence of the angle of attack on the disturbances evolution in the supersonic boundary layer on the swept wing model are obtained. Calculations on the effect of small angles of attack on the development of perturbations are made in the framework of the linear theory of stability. A good qualitative correspondence of theoretical and experimental data are obtained.

  11. Study of the gel films of Acetobacter Xylinum cellulose and its modified samples by {sup 1}H NMR cryoporometry and small-angle X-ray scattering

    Energy Technology Data Exchange (ETDEWEB)

    Babushkina, T. A.; Klimova, T. P. [Russian Academy of Sciences, Nesmeyanov Institute of Organoelement Compounds (Russian Federation); Shtykova, E. V.; Dembo, K. A.; Volkov, V. V. [Russian Academy of Sciences, Shubnikov Institute of Crystallography (Russian Federation); Khripunov, A. K. [Russian Academy of Sciences, Institute of Macromolecular Compounds (Russian Federation); Klechkovskaya, V. V., E-mail: klechvv@ns.crys.ras.ru [Russian Academy of Sciences, Shubnikov Institute of Crystallography (Russian Federation)

    2010-03-15

    Gel films of Acetobacter Xylinum cellulose and its modified samples have been investigated by 1H nuclear magnetic resonance (NMR) cryoporometry and small-angle X-ray scattering. The joint use of these two methods made it possible to characterize the sizes of aqueous pores in gel films and estimate the sizes of structural inhomogeneities before and after the sorption of polyvinylpyrrolidone and Se{sub 0} nanoparticles (stabilized by polyvinylpyrrolidone) into the films. According to small-angle X-ray scattering data, the sizes of inhomogeneities in a gel film change only slightly upon the sorption of polyvinylpyrrolidone and nanoparticles. The impregnated material is sorbed into water-filled cavities that are present in the gel film. {sup 1}H NMR cryoporometry allowed us to reveal the details of changes in the sizes of small aqueous pores during modifications.

  12. Short-term outcome and complications of TPLO using anatomically contoured locking compression plates in small/medium-breed dogs with "excessive" tibial plateau angle.

    Science.gov (United States)

    Barnes, D C; Trinterud, T; Owen, M R; Bush, M A

    2016-06-01

    To report short-term radiographic and clinical outcome and complications following tibial plateau levelling osteotomy for the treatment of cranial cruciate ligament insufficiency in dogs less than 18·1 kg with tibial plateau angle greater than 35° using anatomically contoured six-hole locking compression plates. Retrospective data were collected on: preoperative, postoperative and follow-up tibial plateau angles, plateau segment rotation, tibial tuberosity width and length of the cranial aspect of tibial tuberosity segment from the patellar tendon insertion and rotation of the tibial plateau below the level of the insertion of the patellar ligament. In 26 small dogs (29 stifles in total), mean preoperative, postoperative and follow-up tibial plateau angles were 38·2°, 4·8°, and 4·4°, respectively. Documented postoperative complications were limited to patellar tendinopathy in a single case (3·4%) and tibial tuberosity or fibula fracture were not observed. Short-term radiographic and clinical outcome of tibial plateau levelling osteotomy stabilised with anatomically contoured six-hole locking compression plates for the treatment of small dogs with large tibial plateau angle suggests a very low risk of complications. Rotation beyond the "safe point" is necessary to perform full rotation in some cases, but does not appear to incur an increased risk of tibial tuberosity fracture. © 2016 British Small Animal Veterinary Association.

  13. Imaging with ultra-small-angle X-ray scattering using a Laue-case analyzer and its application to human breast tumors.

    Science.gov (United States)

    Shimao, Daisuke; Sunaguchi, Naoki; Sasaya, Tenta; Yuasa, Tetsuya; Ichihara, Shu; Kawasaki, Tomonori; Ando, Masami

    2017-12-01

    In this study, we demonstrate a novel imaging technique, based on ultra-small-angle X-ray scattering (USAXS) that uses a Laue-case Si wafer as the angle analyzer. We utilized the (1 1 1) diffraction plane of a 356 μm thick, symmetrically cut Si wafer as the angle analyzer, denoted by A[L]. With this device, we performed USAXS imaging experiments using 19.8 keV synchrotron X-rays. The objects we imaged were formalin-fixed, paraffin-embedded breast tumors (an invasive carcinoma and an intraductal papilloma). During image acquisition by a charge-coupled device (CCD) camera, we varied the rotation angle of the analyzer in 0.02″ steps from -2.40″ to +2.40″ around the Bragg angle. The exposure time for each image was 2 s. We determined the amount of ultra-small-angle X-ray scattering from the width of the intensity curve obtained for each local pixel during the rotation of the analyzer. We acquired USAXS images of malignant and benign breast tumor specimens using the A[L] analyzer; regions with larger USAXS form brighter areas in the image. We varied the sensitivity of the USAXS image by changing the threshold level of the object rocking curve. The USAXS images can provide information about the internal distribution of closely packed scattering bodies in a sample with reasonable sensitivity. This information differs from that obtainable through refraction-contrast imaging. Although further validation studies will be necessary, we conclude that USAXS imaging using a Laue-case analyzer may have significant potential as a new diagnosis technique. Copyright © 2017 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

  14. Angle-Dependent Ionization of Small Molecules by Time-Dependent Configuration Interaction and an Absorbing Potential.

    Science.gov (United States)

    Krause, Pascal; Schlegel, H Bernhard

    2015-06-04

    The angle-dependence of strong field ionization of O2, N2, CO2, and CH2O has been studied theoretically using a time-dependent configuration interaction approach with a complex absorbing potential (TDCIS-CAP). Calculation of the ionization yields as a function of the direction of polarization of the laser pulse produces three-dimensional surfaces of the angle-dependent ionization probability. These three-dimensional shapes and their variation with laser intensity can be interpreted in terms of ionization from the highest occupied molecular orbital (HOMO) and lower lying orbitals, and the Dyson orbitals for the ground and excited states of the cations.

  15. Assessment of firing conditions in old fired-clay bricks. The contribution of X-ray powder diffraction with the Rietveld method and small angle neutron scattering

    Czech Academy of Sciences Publication Activity Database

    Viani, Alberto; Sotiriadis, Konstantinos; Len, A.; Šašek, Petr; Ševčík, Radek

    2016-01-01

    Roč. 116, June (2016), s. 33-43 ISSN 1044-5803 R&D Projects: GA MŠk(CZ) LO1219 Keywords : fired- clay brick * Rietveld method * small angle neutron scattering * X-ray diffraction * firing temperature Subject RIV: AL - Art, Architecture, Cultural Heritage Impact factor: 2.714, year: 2016 http://www.sciencedirect.com/science/article/pii/S1044580316300870

  16. Frequency-Tracking CW Doppler Radar Solving Small-Angle Approximation and Null Point Issues in Non-Contact Vital Signs Monitoring.

    Science.gov (United States)

    Mercuri, Marco; Liu, Yao-Hong; Lorato, Ilde; Torfs, Tom; Bourdoux, Andre; Van Hoof, Chris

    2017-06-01

    A Doppler radar operating as a Phase-Locked-Loop (PLL) in frequency demodulator configuration is presented and discussed. The proposed radar presents a unique architecture, using a single channel mixer, and allows to detect contactless vital signs parameters while solving the null point issue and without requiring the small angle approximation condition. Spectral analysis, simulations, and experimental results are presented and detailed to demonstrate the feasibility and the operational principle of the proposed radar architecture.

  17. In-situ small-angle x-ray scattering study of nanoparticles in the plasma plume induced by pulsed laser irradiation of metallic targets

    Energy Technology Data Exchange (ETDEWEB)

    Lavisse, L.; Jouvard, J.-M.; Girault, M.; Potin, V.; Andrzejewski, H.; Marco de Lucas, M. C.; Bourgeois, S. [Laboratoire Interdisciplinaire Carnot de Bourgogne (ICB), UMR 6303 CNRS-Universite de Bourgogne, 9 Avenue A. Savary, BP 47870-21078 Dijon Cedex (France); Le Garrec, J.-L.; Carles, S.; Mitchell, J. B. A. [Institut de Physique de Rennes, UMR 6251 CNRS-Universite de Rennes 1, 35042 Rennes Cedex (France); Hallo, L. [CEA CESTA, 15 Avenue des Sablieres CS 60001, 33116 Le Barp Cedex (France); Perez, J. [Synchrotron SOLEIL, L' Orme des Merisiers, Saint-Aubin, F-91192 Gif-sur-Yvette Cedex (France); Decloux, J. [Kaluti System, Optique et Laser, Centre Scientifique d' Orsay, 91400 Orsay (France)

    2012-04-16

    Small angle x-ray scattering was used to probe in-situ the formation of nanoparticles in the plasma plume generated by pulsed laser irradiation of a titanium metal surface under atmospheric conditions. The size and morphology of the nanoparticles were characterized as function of laser irradiance. Two families of nanoparticles were identified with sizes on the order of 10 and 70 nm, respectively. These results were confirmed by ex-situ transmission electron microscopy experiments.

  18. Microstructure of amorphous-silicon-based solar cell materials by small-angle x-ray scattering. Annual subcontract report, 6 April 1994--5 April 1995

    Energy Technology Data Exchange (ETDEWEB)

    Williamson, D.L. [Colorado School of Mines, Golden, CO (United States)

    1995-08-01

    The general objective of this research is to provide detailed microstructural information on the amorphous-silicon-based, thin-film materials under development for improved multijunction solar cells. The experimental technique used is small-angle x-ray scattering (SAXS) providing microstructural data on microvoid fractions, sizes, shapes, and their preferred orientations. Other microstructural features such as alloy segregation, hydrogen-rich clusters and alloy short-range order are probed.

  19. Small-angle x-ray scattering investigation of the effect of heating temperature on the submicroscopic pore structure of wood charcoal

    Energy Technology Data Exchange (ETDEWEB)

    Schmidt, P.W.; Kalliat, M.; Cutter, B.E.

    1984-01-01

    Small-angle x-ray scattering investigations are performed on charcoal samples from black cherry wood which were heated to temperatures ranging from 600/sup 0/ to 2000/sup 0/C during pyrolysis. This report summarizes the results of these investigations which give information about the pore structure of black cherry wood. The authors also develop a general picture of the dependence of charcoal porosity on the temperature to which the wood was heated during pyrolysis.

  20. Frozen concentration fluctuations in a poly(N-isopropyl acrylamide) gel studied by neutron spin echo and small-angle neutron scattering

    CERN Document Server

    Koizumi, S; Richter, D; Schwahn, D; Faragó, B; Annaka, M

    2002-01-01

    By employing neutron spin echo and small-angle neutron scattering, we determined the structure factor of the frozen concentration fluctuations on nano-length scales in a swollen poly(N-isopropyl acrylamide) gel. The frozen contribution, showing a plateau at the low scattering wavenumber q (0.02 A sup - sup 1), is intimately related to the abnormal butterfly scattering pattern appearing at low q under deformation. (orig.)

  1. Structural evolution of regenerated silk fibroin under shear: Combined wide- and small-angle x-ray scattering experiments using synchrotron radiation

    Energy Technology Data Exchange (ETDEWEB)

    Rossle, Manfred [European Molecular Biology Laboratory (EMBL), France; Panine, Pierre [European Synchrotron Radiation Facility (ESRF); Urban, Volker S [ORNL; Riekel, Christine [European Synchrotron Radiation Facility (ESRF)

    2004-04-01

    The structural evolution of regenerated Bombyx mori silk fibroin during shearing with a Couette cell has been studied in situ by synchrotron radiation small- and wide-angle x-ray scattering techniques. An elongation of fibroin molecules was observed with increasing shear rate, followed by an aggregation phase. The aggregates were found to be amorphous with {beta}-conformation according to infrared spectroscopy. Scanning x-ray microdiffraction with a 5 {micro}m beam on aggregated material, which had solidified in air, showed silk II reflections and a material with equatorial reflections close to the silk I structure reflections, but with strong differences in reflection intensities. This silk I type material shows up to two low-angle peaks suggesting the presence of water molecules that might be intercalated between hydrogen-bonded sheets.

  2. Feature extraction of micro-motion frequency and the maximum wobble angle in a small range of missile warhead based on micro-Doppler effect

    Science.gov (United States)

    Li, M.; Jiang, Y. S.

    2014-11-01

    Micro-Doppler effect is induced by the micro-motion dynamics of the radar target itself or any structure on the target. In this paper, a simplified cone-shaped model for ballistic missile warhead with micro-nutation is established, followed by the theoretical formula of micro-nutation is derived. It is confirmed that the theoretical results are identical to simulation results by using short-time Fourier transform. Then we propose a new method for nutation period extraction via signature maximum energy fitting based on empirical mode decomposition and short-time Fourier transform. The maximum wobble angle is also extracted by distance approximate approach in a small range of wobble angle, which is combined with the maximum likelihood estimation. By the simulation studies, it is shown that these two feature extraction methods are both valid even with low signal-to-noise ratio.

  3. A small-angle X-ray scattering study of complexes formed in mixtures of a cationic polyelectrolyte and an anionic surfactant

    DEFF Research Database (Denmark)

    Bergström, M.; Kjellin, U.R.M.; Claesson, P.M.

    2002-01-01

    The internal structure of the solid phase formed in mixtures of the anionic surfactant sodium dodecyl sulfate (SDS) and a range of oppositely charged polyelectrolytes with different side chains and charge density has been investigated using small-angle X-ray scattering. Polyelectrolytes with short...... from a=47.7 Angstrom (MAPTAC, 100% charge density) to 58.5 Angstrom (AM-MAPTAC, 30% charge density). The unit cell length in the lamellar SDS/PVAm complex (a=36.1 Angstrom) is significantly smaller than for the different hexagonal structures. It is conjectured that the cylinders in the hexagonal...

  4. 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

    . The present work shows that the same information can be obtained by combining static light scattering (SLS) and small-angle X-ray scattering (SAXS), which provide information on, respectively, large and short length scales. Micelles of a series of block copolymers of poly(ethylene propylene...... 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...

  5. Application of small-angle X-ray scattering to the characterization and quantification of the drug transport nanosystem based on the soybean phosphatidylcholine.

    Science.gov (United States)

    Kiselev, M A; Zemlyanaya, E V; Ipatova, O M; Gruzinov, A Yu; Ermakova, E V; Zabelin, A V; Zhabitskaya, E I; Druzhilovskaya, O S; Aksenov, V L

    2015-10-10

    Phospholipid transport nanosystem (PTNS) for drug delivery is based on soybean phosphatidylcholine. The morphology of PTNS is investigated by means of small-angle X-ray scattering. The obtained results allow one to answer the key question from the viewpoint of organization of drug incorporation whether the PTNS nanoparticles have a structure of micelles or vesicles. It is demonstrated that PTNS is a vesicular system with an average vesicle radius of 160 ± 2Å. Copyright © 2015 Elsevier B.V. All rights reserved.

  6. 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.

  7. Small angle x-ray scattering: Instrument development and studies of protein aggregation, cellulose hydrolysis, and the production of nanoporous metals using surfactact templates

    Science.gov (United States)

    Banuelos, Jose Leobardo

    Small angle x-ray scattering (SAXS) was used to obtain structural insights into protein aggregation, the enzymatic hydrolysis of cellulose, and the structural evolution of surfactant-templated nanoporous palladium and platinum systems during their synthesis. SAXS is bulk technique that allows probing the nanometer-scale morphology, interactions, density, and distribution of a variety of nonperiodic systems in the solid, liquid, or gaseous state. A 10-meter Small Angle Scattering camera, originally at ORNL, was assembled. During its re-commissioning, several upgrades were made including new data acquisition software built using National Instrument's Labview development environment, as well as portability to use analysis tools in wide use in scattering community. The Multiple Energy Diffractometer Using Small, medium and wide Angles (MEDUSA) was designed and built, its development will be discussed. The ability of proteins to change their conformation in response to changes in pressure, temperature, the presence of other molecular species, and ionic concentration in the solvents they are found, is a remarkable phenomenon that allows living cells to function properly. When proteins irreversibly unfold or mis-fold and aggregate this gives rise to severely debilitating diseases such as Alzheimer's and prion diseases. Protein aggregation was measured using SAXS on aqueous solutions of bovine serum albumin, myoglobin, and cellulase enzymes. Understanding how cellulose can be broken down into fermentable sugars is an important step in the development of strategies for producing alternative energy from biomass. The enzymatic hydrolysis of cellulose was studied using both small angle neutron scattering and SAXS. One result from these investigations was finding supporting evidence that nanopores within the cellulose fibril matrix allow biologically active enzymes access to digest parts of the fibers. The production of mesoporous materials for hydrogen storage applications was

  8. 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 comm......-format input files and is currently compatible with one-dimensional data files from SAXS beamlines at a number of synchrotron facilities. BioXTAS RAW is written in Python with C++ extensions....

  9. Observation of dust particles ejected from the tungsten surface by transient heat flux with small-angle scattering of cw laser light

    Directory of Open Access Journals (Sweden)

    L.N. Vyacheslavov

    2017-08-01

    Full Text Available A new test facility for experimental simulation of transient heat load expected in the ITER divertor during unmitigated events is developed. Application of a long-pulse (0.1–0.3ms wide-aperture (up to 2cm2 electron beam as a heating device provides powerful energy loads at a tungsten target with FHF> 250MJm−2s−0.5. Dynamics of tungsten particles in the ablation plume is investigated with a novel for PSI experiments small-angle laser light scattering technique. The threshold of intense droplet generation and dynamics of particles sizes are estimated.

  10. Growth Kinetics of Polyelectrolyte Complexes Formed from Oppositely-Charged Homopolymers Studied by Time-Resolved Ultra-Small-Angle X-ray Scattering.

    Science.gov (United States)

    Takahashi, Rintaro; Narayanan, Theyencheri; Sato, Takahiro

    2017-02-16

    We have monitored the kinetic process of polyelectrolyte complex formation between sodium polyacrylate (SPA) and polyallylamine hydrochrolide (PAH) in aqueous NaCl solution by time-resolved ultra-small-angle X-ray scattering (TR-USAXS) combined with rapid mixing. SPA and PAH with different NaCl concentrations from 0 to 1 M were rapidly mixed in equimolar concentration of the monomer units using a stopped-flow apparatus with a dead time of about 2.5 ms. Within the dead time, percolated aggregate-like structures were observed suggesting that the initially formed small charge neutral aggregates further assembled to form higher order agglomerates. The early stage time evolution of the molar mass of the global structure in the presence of NaCl was found to be comparable to the Brownian-coagulation rate.

  11. Very large-scale structures in sintered silica aerogels as evidenced by atomic force microscopy and ultra-small angle X-ray scattering experiments

    CERN Document Server

    Marliere, C; Etienne, P; Woignier, T; Dieudonné, P; Phalippou, J

    2001-01-01

    During the last few years the bulk structure of silica aerogels has been extensively studied mainly by scattering techniques (neutrons, X-rays, light). It has been shown that small silica particles aggregate to constitute a fractal network. Its spatial extension and fractal dimension are strongly dependent on the synthesis conditions (e.g., pH of gelifying solutions). These typical lengths range from 1 to 10 nm. Ultra-small angle X-ray scattering (USAXS) and atomic force microscopy (AFM) experiments have been carried out on aerogels at different steps of densification. The results presented in this paper reveal the existence of a spatial arrangement of the solid part at a very large length scale. The evolution of this very large-scale structure during the densification process has been studied and reveals a contraction of this macro-structure made of aggregates of clusters. (16 refs).

  12. Weak self-interactions of globular proteins studied by small-angle X-ray scattering and structure-based modeling

    CERN Document Server

    Kaieda, Shuji; Plivelic, Tomás S; Halle, Bertil

    2014-01-01

    We investigate protein-protein interactions in solution by small-angle X-ray scattering (SAXS) and theoretical modeling. The structure factor for solutions of bovine pancreatic trypsin inhibitor (BPTI), myoglobin (Mb), and intestinal fatty acid-binding protein (IFABP) is determined from SAXS measurements at multiple concentrations, from Monte Carlo simulations with a coarse-grained structure-based interaction model, and from analytic approximate solutions of two idealized colloidal interaction models without adjustable parameters. By combining these approaches, we find that the structure factor is essentially determined by hard-core and screened electrostatic interactions. Other soft short-ranged interactions (van der Waals and solvation-related) are either individually insignificant or tend to cancel out. The structure factor is also not significantly affected by charge fluctuations. For Mb and IFABP, with small net charge and relatively symmetric charge distribution, the structure factor is well described b...

  13. Cavitating flow control through continuous tangential mass injection on a 2D hydrofoil at a small attack angle

    Directory of Open Access Journals (Sweden)

    Timoshevskiy Mikhail V.

    2016-01-01

    Full Text Available We studied cavitating flow over the suction side of a symmetric 2D foil – a scaled-down model of high-pressure hydroturbine guide vanes (GV – in different cavitation regimes at the attack angle of 3°. High-speed imaging was used to analyze spatial patterns and time dynamics of the gas-vapour cavities. A hydroacoustic pressure transducer was employed to register time-spectra of pressure fluctuations nearby the hydrofoil. A PIV technique was applied to measure the velocity fields and its fluctuations. The active flow control was implemented by means of a continuous liquid supply with different flow rates through a slot channel located in the GV surface. It was found that the active mass injection does not influence the primary flow upstream of the slot channel position. For the cavitation-free and cavitation inception cases, the injection was shown to make the turbulent wake past the GV section more intense. However, at the developed cavitation regimes the active flow management made it possible to reduce substantially the amplitude or even totally suppress the periodic cavity length oscillations and pressure pulsations associated with them.

  14. A freeze-fracture transmission electron microscopy and small angle x-ray diffraction study of the effects of albumin, serum, and polymers on clinical lung surfactant microstructure.

    Science.gov (United States)

    Braun, Andreas; Stenger, Patrick C; Warriner, Heidi E; Zasadzinski, Joseph A; Lu, Karen W; Taeusch, H William

    2007-07-01

    Freeze-fracture transmission electron microscopy shows significant differences in the bilayer organization and fraction of water within the bilayer aggregates of clinical lung surfactants, which increases from Survanta to Curosurf to Infasurf. Albumin and serum inactivate all three clinical surfactants in vitro; addition of the nonionic polymers polyethylene glycol, dextran, or hyaluronic acid also reduces inactivation in all three. Freeze-fracture transmission electron microscopy shows that polyethylene glycol, hyaluronic acid, and albumin do not adsorb to the surfactant aggregates, nor do these macromolecules penetrate the interior water compartments of the surfactant aggregates. This results in an osmotic pressure difference that dehydrates the bilayer aggregates, causing a decrease in the bilayer spacing as shown by small angle x-ray scattering and an increase in the ordering of the bilayers as shown by freeze-fracture electron microscopy. Small angle x-ray diffraction shows that the relationship between the bilayer spacing and the imposed osmotic pressure for Curosurf is a screened electrostatic interaction with a Debye length consistent with the ionic strength of the solution. The variation in surface tension due to surfactant adsorption measured by the pulsating bubble method shows that the extent of surfactant aggregate reorganization does not correlate with the maximum or minimum surface tension achieved with or without serum in the subphase. Albumin, polymers, and their mixtures alter the surfactant aggregate microstructure in the same manner; hence, neither inhibition reversal due to added polymer nor inactivation due to albumin is caused by alterations in surfactant microstructure.

  15. Trends in anomalous small-angle X-ray scattering in grazing incidence for supported nanoalloyed and core-shell metallic nanoparticles

    Science.gov (United States)

    Andreazza, P.; Khelfane, H.; Lyon, O.; Andreazza-Vignolle, C.; Ramos, A. Y.; Samah, M.

    2012-06-01

    As atomic structure and morphology of particles are directly correlated to their functional properties, experimental methods probing local and average features of particles at the nanoscale elicit a growing interest. Anomalous small-angle X-ray scattering (ASAXS) is a very attractive technique to investigate the size, shape and spatial distribution of nanoobjects embedded in a homogeneous matrix or in porous media. The anomalous variation of the scattering factor close to an absorption edge enables element specific investigations. In the case of supported nano-objects, the use of grazing incidence is necessary to limit the probed depth. The combination of grazing incidence with the anomalous technique provides a powerful new method, anomalous grazing incidence small-angle X-ray scattering (AGISAXS), to disentangle complex chemical patterns in supported multi-component nano-structures. Nevertheless, a proper data analysis requires accurate quantitative measurements associated to an adapted theoretical framework. This paper presents anomalous methods applied to nanoalloys phase separation in the 1-10 nm size range, and focuses on the application of AGISAXS in bimetallic systems: nanocomposite films and core-shell supported nanoparticles.

  16. Architecture of a Full-length Retroviral Integrase Monomer and Dimer, Revealed by Small Angle X-ray Scattering and Chemical Cross-linking

    Energy Technology Data Exchange (ETDEWEB)

    Bojja, Ravi S.; Andrake, Mark D.; Weigand, Steven; Merkel, George; Yarychkivska, Olya; Henderson, Adam; Kummerling, Marissa; Skalka, Anna Marie (Fox Chase); (NWU)

    2012-02-07

    We determined the size and shape of full-length avian sarcoma virus (ASV) integrase (IN) monomers and dimers in solution using small angle x-ray scattering. The low resolution data obtained establish constraints for the relative arrangements of the three component domains in both forms. Domain organization within the small angle x-ray envelopes was determined by combining available atomic resolution data for individual domains with results from cross-linking coupled with mass spectrometry. The full-length dimer architecture so revealed is unequivocally different from that proposed from x-ray crystallographic analyses of two-domain fragments, in which interactions between the catalytic core domains play a prominent role. Core-core interactions are detected only in cross-linked IN tetramers and are required for concerted integration. The solution dimer is stabilized by C-terminal domain (CTD-CTD) interactions and by interactions of the N-terminal domain in one subunit with the core and CTD in the second subunit. These results suggest a pathway for formation of functional IN-DNA complexes that has not previously been considered and possible strategies for preventing such assembly.

  17. Assessment of firing conditions in old fired-clay bricks: The contribution of X-ray powder diffraction with the Rietveld method and small angle neutron scattering

    Energy Technology Data Exchange (ETDEWEB)

    Viani, Alberto, E-mail: viani@itam.cas.cz [Institute of Theoretical and Applied Mechanics AS CR, Centre of Excellence Telč, Batelovská 485, CZ-58856 Telč (Czech Republic); Sotiriadis, Konstantinos [Institute of Theoretical and Applied Mechanics AS CR, Centre of Excellence Telč, Batelovská 485, CZ-58856 Telč (Czech Republic); Len, Adél [Wigner Research Centre for Physics HAS, Konkoly-Thege 29-33, 1121 Budapest (Hungary); Šašek, Petr; Ševčík, Radek [Institute of Theoretical and Applied Mechanics AS CR, Centre of Excellence Telč, Batelovská 485, CZ-58856 Telč (Czech Republic)

    2016-06-15

    Full characterization of fired-clay bricks is crucial for the improvement of process variables in manufacturing and, in case of old bricks, for restoration/replacement purposes. To this aim, five bricks produced in a plant in Czech Republic in the past have been investigated with a combination of analytical techniques in order to derive information on the firing process. An additional old brick from another brickyard was also used to study the influence of different raw materials on sample microstructure. The potential of X-ray diffraction with the Rietveld method and small angle neutron scattering technique has been exploited to describe the phase transformations taking place during firing and characterize the brick microstructure. Unit-cell parameter of spinel and amount of hematite are proposed as indicators of the maximum firing temperature, although for the latter, limited to bricks produced from the same raw material. The fractal quality of the surface area of pores obtained from small angle neutron scattering is also suggested as a method to distinguish between bricks produced from different raw clays. - Highlights: • Rietveld method helps in describing microstructure and physical properties of bricks. • XRPD derived cell parameter of spinel is proposed as an indicator of firing temperature. • SANS effectively describes brick micro and nanostructure, including closed porosity. • Fractal quality of pore surface is proposed as ‘fingerprint’ of brick manufacturing.

  18. Order and orientation control of mesoporous silica films on conducting gold substrates formed by dip-coating and self-assembly: a grazing angle of incidence small-angle X-ray scattering and field emission scanning electron microscopy study.

    Science.gov (United States)

    Tate, Michael P; Eggiman, Brian W; Kowalski, Jonathan D; Hillhouse, Hugh W

    2005-10-25

    Grazing-angle of incidence small-angle X-ray scattering (GISAXS) and high-resolution field emission scanning electron microscopy have been used to characterize the mesophase symmetry, orientation, and long-range order in PEO20-PPO70-PEO20 (Pluronic P123) templated mesoporous silica thin films on conducting gold substrates as a function of silica-to-ethylene oxide (Si/EO) block ratio and relative humidity (RH). The films are formed by dip-coating followed by evaporation-induced self-assembly under tightly controlled RH. The general evolution of the mesophase follows the trends that are expected based on shape factors due to swelling of the PEO block. However, changes in orientation of the nanostructure relative to the substrate and the degree of long-range order are found to depend on Si/EO ratio. These effects are likely due to the dynamics of evaporation and self-assembly. Generally, at Si/EO ratios lower than 3.29, the films contained regions where the nanostructure was not oriented relative to the plane of the substrate. However, for Si/EO ratios greater than 3.62, conditions were found where the nanostructure of the film was highly oriented relative to the plane of the substrate. This is true over the range of RH studied, independent of the nanostructure symmetry. For low Si/EO ratios at the highest RH levels, the films were composed of a mixture of spherical and cylindrical pores. At high Si/EO ratios and high RH levels, the films had a highly oriented R-3m nanostructure but displayed streaking perpendicular to the substrate in the Bragg spots on GISAXS patterns. This streaking is interpreted as faulting along planes parallel to the substrate.

  19. 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.

  20. Analysis of X-band calibrated sea clutter and small boat reflectivity at medium-to-low grazing angles

    CSIR Research Space (South Africa)

    Herselman, PL

    2008-11-01

    Full Text Available surface often exceeds the boat RCS by up to 10 dB. With improved subclutter visibility, the problem arises that first detections are declared not only for small boats, but also for large birds such as seagulls, with a typical RCS of 0.01–0.1 m2 [3... 04-Nov 06-Nov 10-Nov 13-Nov 17-NovW in d sp ee d (kt s) 0 7.5 15 22.5 30 W in d di re ct io n (◦ N ) −180 −90 0 90 180 Speed-local Speed-Robben island Direction-local Direction-Robben island (a) Wave height...

  1. Conformation and arrangement of polyelectrolytes in semi-diluted solution. A study by small angle neutrons scattering; Conformation et arrangement des polyelectrolytes en solution semi-diluee. Etude par diffusion des neutrons aux petits angles

    Energy Technology Data Exchange (ETDEWEB)

    Spiteri, M.N.

    1997-03-25

    Polyelectrolytes have particular physical and chemical properties and can thus be used for instance for petroleum production. Some of their microscopic properties have been studied in this work. With the particular zero average contrast technique, the small angle neutron scattering allows to directly know the form factors in semi-diluted solutions of polyelectrolytes where the chains are mixed. Another measure leads to the crystal structure. The electrostatic screen effects when salt is added in aqueous solutions of completely charged PSSNa solutions (f=1) (sodium polystyrene sulfonate) are studied. It seems that the chains take a vermiform conformation. Their persistence length varies as I{sup -1/3} (I is the ionic force). The hydrophobicity effects in partially charged PSSNa solutions (f<1) are given too. They lead to a progressive collapse of the chains when their charge rates decrease. The screen and condensation effects when the charge rate f of the PSSNa (f>f(Manning)) varies in a polar solvent (DMSO) are studied. The vermiform chains have the same persistence length (for each f) which varies as I{sup -1/4}. Lastly, the f variation effects in the case of a weakly charged hydrophilic poly-ion (f

  2. Measurements on small angle elastic scattering from p p and anti-p p collisions at the ISR

    CERN Document Server

    Shukla, Shekhar

    1986-01-01

    Experiment R211 was performed at the Intersecting Storage rings (ISR) of the European Center for Nuclear Research (CERN), Geneva, Switzerland. The aim was to measure, for pp and anti-p(p) scattering at high energy, the three quantities: (1) the total nuclear cross section, σ/sub n/, (2) the nuclear slope parameter, b, that describes the dependence of the differential elastic cross section on the 4- momentum transfer, t, for small absolute value of t, and (3) the ratio, rho, of the real to the imaginary part of the forward nuclear elastic scattering amplitude. These quantities were deduced from differential elastic scattering cross sections measured in the near forward direction. The measurements were made for pp scattering at √s = 30.5 GeV, 52.8 GeV and 62.5 GeV. The total cross section for both pp and anti-p(p) scattering is seen to rise in the range √s = 30.5 GeV to √s = 62.5 GeV. The rise is consistent with an asymptotic increase of σ/sub n/ as In2(s/s0), the highest rate allowed by the Froissart b...

  3. Effects of two-dimensional magnetic uncertainties and three-dimensional error and perturbation fields on the Small Angle Slot divertor geometry and topology

    Science.gov (United States)

    Trevisan, G. L.; Lao, L. L.; Evans, T. E.; Guo, H. Y.; Orlov, D. M.; Strait, E. J.; Wingen, A.; Wu, W.

    2018-02-01

    The Small Angle Slot (SAS) was recently installed on DIII-D as an advanced divertor, promising easier plasma detachment and lower temperatures across the whole target. A twofold study of the SAS magnetic geometry and topology is presented in this paper. On one hand, a two-dimensional uncertainty quantification analysis is carried out through a Monte Carlo approach in order to understand the level of accuracy of two-dimensional equilibrium computations in reconstructing the strike point and angle onto the divertor. Under typical experimental conditions, the uncertainties are found to be roughly 6.8 mm and 0.56 deg, respectively. On the other hand, a three-dimensional ‘vacuum’ analysis is carried out to understand the effects of typical external perturbation fields on the scrape-off layer topology. When the non-axisymmetric I-coils are switched on, poloidally-localized lobes are found to appear, grow, and hit the SAS target, although barely, even for 5 kA; at the same time, the strike point modulation is found to be roughly 1.8 mm and thus negligible for most purposes. Such results complement previous two-dimensional analyses in characterizing typical SAS equilibria and provide useful background information for planning and interpreting SAS experiments.

  4. MDCT abnormalities of small- and medium-sized bronchus in active tuberculosis: a new angle on an old disease

    Energy Technology Data Exchange (ETDEWEB)

    Oh, Jin Kyoung; Ahn, Myeong Im; Jung, Jung Im; Han, Dae Hee (Dept. of Radiology, Seoul St Mary' s Hospital, The Catholic Univ. of Korea, Seoul (Korea, Republic of)), email: lepolder@gmail.com; Kim, Young Kyoon (Dept. of Internal Medicine, Seoul St Mary' s Hospital, The Catholic Univ. of Korea, Seoul (Korea, Republic of)); Oh, Eun-Jee; Park, Yeon-Joon (Dept. of Laboratory Medicine, Seoul St Mary' s Hospital, The Catholic Univ. of Korea, Seoul (Korea, Republic of))

    2011-02-15

    Background: The incidence and findings of tuberculous invasion of the peripheral bronchus have not been fully investigated with MDCT. Purpose: To evaluate the prevalence and findings of MDCT abnormalities of small- and medium-sized bronchus (SMB) in active pulmonary tuberculosis (TB). Material and Methods: Using multiplanar reformation, 35 consecutive MDCT scans (follow-up exams available in 14 patients with a mean interval of 8.1 months) were assessed for following abnormalities of SMB: bronchial impaction (BI), wall thickening, dilatation, peribronchial cuff of soft tissue, and bronchocavitary fistula. It was also assessed whether tree-in-buds (TIB) have a tendency to distribute in the territories of diseased SMB, and whether SMB abnormalities are present in patients with relatively mild disease. Results: SMB abnormalities were observed in 23 (65.7%) patients with active TB. The most frequent finding was wall thickening (n=18, 51.4%), followed by BI (n=13, 37.1%; zigzag-shaped in four), dilatation (n =11, 31.4%), amputated appearance of air column (n=11, 31.4%), peribronchial cuff of soft tissue (n=10, 28.6%), and bronchocavitary fistula (n=8, 22.9%). TIB (n=29; absent in two patients with SMB) was mainly within (n=14) or close to (n=4) the territory of diseased SMB. Follow-up CT frequently showed improvement of wall thickening (11/12) and persistence of bronchial dilatation (11/13). SMB abnormality was present in all of six patients with mild disease. Conclusion: MDCT shows that tuberculous invasion of the peripheral bronchus may be more frequent than previously thought, of which findings include wall thickening, BI, dilatation, amputated appearance of air column, peribronchial cuff of soft tissue and bronchocavitary fistula

  5. Application of ultra-small-angle X-ray scattering / X-ray photon correlation spectroscopy to relate equilibrium or non-equilibrium dynamics to microstructure

    Science.gov (United States)

    Allen, Andrew; Zhang, Fan; Levine, Lyle; Ilavsky, Jan

    2013-03-01

    Ultra-small-angle X-ray scattering (USAXS) can probe microstructures over the nanometer-to-micrometer scale range. Through use of a small instrument entrance slit, X-ray photon correlation spectroscopy (XPCS) exploits the partial coherence of an X-ray synchrotron undulator beam to provide unprecedented sensitivity to the dynamics of microstructural change. In USAXS/XPCS studies, the dynamics of local structures in a scale range of 100 nm to 1000 nm can be related to an overall hierarchical microstructure extending from 1 nm to more than 1000 nm. Using a point-detection scintillator mode, the equilibrium dynamics at ambient temperature of small particles (which move more slowly than nanoparticles) in aqueous suspension have been quantified directly for the first time. Using a USAXS-XPCS scanning mode for non-equilibrium dynamics incipient processes within dental composites have been elucidated, prior to effects becoming detectable using any other technique. Use of the Advanced Photon Source, an Office of Science User Facility operated for the United States Department of Energy (U.S. DOE) Office of Science by Argonne National Laboratory, was supported by the U.S. DOE under Contract No. DE-AC02-06CH11357.

  6. Small-Angle Fibre Diffraction Studies of Cornela Matrix Structure: A Depth-Profiled Investigation of the Human Eye-Bank Cornea

    Energy Technology Data Exchange (ETDEWEB)

    Quantock,A.; Boote, C.; Young, R.; Hayes, S.; Tanioka, H.; Kawasaki, S.; Ohta, N.; Lida, T.; Yagi, N.; et al.

    2007-01-01

    In the cornea of the eye light transmission is facilitated by the regular arrangement and uniform diameter of collagen fibrils that constitute the bulk of the extracellular corneal matrix. Matrix architecture, in turn, is believed to be governed by interactions between collagen fibrils and proteoglycan molecules modified with sulfated glycosaminoglycan side chains. Here, we outline the contribution made by small-angle X-ray scattering studies of the cornea in understanding the role of sulfated glycosaminoglycans in the control of collagen architecture in cornea, and present new depth-profiled microbeam data from swollen human eye-bank corneas that indicate no significant change in collagen fibril diameter throughout the tissue, but a lower collagen interfibrillar spacing in the anterior-most stromal regions compared with the ultrastructure of the deeper cornea.

  7. Detection of short range order in SiO{sub 2} thin-films by grazing-incidence wide and small-angle X-ray scattering

    Energy Technology Data Exchange (ETDEWEB)

    Nagata, Kohki, E-mail: nagata.koki@iri-tokyo.jp [Tokyo Metropolitan Industrial Technology Research Institute, 2-4-10 Aomi, Koto-ku, Tokyo 135-0064 (Japan); School of Science and Technology, Meiji University, 1-1-1 Higashimita, Tama-ku, Kawasaki, Kanagawa 214-8571 (Japan); Ogura, Atsushi [School of Science and Technology, Meiji University, 1-1-1 Higashimita, Tama-ku, Kawasaki, Kanagawa 214-8571 (Japan); Hirosawa, Ichiro [Japan Synchrotron Radiation Research Institute (JASRI), 1-1-1, Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5198 (Japan); Suwa, Tomoyuki; Teramoto, Akinobu; Ohmi, Tadahiro [New Industry Creation Hatchery Center, Tohoku University, 6-6-10 Aramakiazaaoba, Aoba-ku, Sendai, Miyagi 980-8579 (Japan)

    2016-04-21

    The effects of the fabrication process conditions on the microstructure of silicon dioxide thin films of <10 nm thickness are presented. The microstructure was investigated using grazing-incidence wide and small-angle X-ray scattering methods with synchrotron radiation. The combination of a high brilliance light source and grazing incident configuration enabled the observation of very weak diffuse X-ray scattering from SiO{sub 2} thin films. The results revealed different microstructures, which were dependent on oxidizing species or temperature. The micro-level properties differed from bulk properties reported in the previous literature. It was indicated that these differences originate from inner stress. The detailed structure in an amorphous thin film was not revealed owing to detection difficulties.

  8. Small angle x-ray studies reveal that Aspergillus niger glucoamylase has a defined extended conformation and can form dimers in solution

    DEFF Research Database (Denmark)

    Jørgensen, Anders Dysted; Nøhr, Jane; Kastrup, Jette Sandholm

    2008-01-01

    The industrially important glucoamylase 1 is an exo-acting glycosidase with substrate preference for alpha-1,4 and alpha-1,6 linkages at non-reducing ends of starch. It consists of a starch binding and a catalytic domain interspersed by a highly glycosylated polypeptide linker. The linker function...... is poorly understood and structurally undescribed, and data regarding domain organization and intramolecular functional cooperativity are conflicting or non-comprehensive. Here, we report a combined small angle x-ray scattering and calorimetry study of Aspergillus niger glucoamylase 1, glucoamylase 2, which...... lacks a starch binding domain, and an engineered low-glycosylated variant of glucoamylase 1 with a short linker. Low resolution solution structures show that the linker adopts a compact structure rendering a well defined extended overall conformation to glucoamylase. We demonstrate that binding...

  9. 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.

  10. In situ electrochemical small-angle neutron scattering (eSANS) for quantitative structure and redox properties of polymer-coated nanoparticles

    Science.gov (United States)

    Prabhu, Vivek; Reipa, Vytas; Bonnesen, Peter; Rondinone, Adam; Formo, Eric

    2012-02-01

    Rapid growth in nanomaterial applications (energy, cosmetics and healthcare products) highlights limitations of available physicochemical characterization methods. An in situ electrochemical small-angle neutron scattering (eSANS) methodology was devised that enables direct measurements of nano and colloid material dispersion structure while undergoing reduction-oxidation (redox) reactions. By combining the electrochemical signal with contrast variant SANS, the structure of the polymer-nanoparticle complexes can be examined under electrochemical conditions. Specially-synthesized poly(ethyleneglycol)-stabilized zinc oxide nanoparticles were examined by eSANS showing an irreversible change in nanoparticle-complex structure during the potential cycle. We will report on the kinetics of the nanoparticle transformation as measured at BL-6 EQSANS, Spallation Neutron Source, Oak Ridge National Laboratory.

  11. Gas gain operations with single photon resolution using an integrating ionization chamber in small-angle X-ray scattering experiments

    CERN Document Server

    Menk, R H; Besch, H J; Walenta, Albert H; Amenitsch, H; Bernstorff, S

    2000-01-01

    In this work a combination of an ionization chamber with one-dimensional spatial resolution and a MicroCAT structure will be presented. Initially, MicroCAT was thought of as a shielding grid (Frisch-grid) but later was used as an active electron amplification device that enables single X-ray photon resolution measurements at low fluxes even with integrating readout electronics. Moreover, the adjustable gas gain that continuously covers the entire range from pure ionization chamber mode up to high gas gains (30000 and more) provides stable operation yielding a huge dynamic range of about 10 sup 8 and more. First measurements on biological samples using small angle X-ray scattering techniques with synchrotron radiation will be presented.

  12. Exploring Pore Formation of Atomic Layer-Deposited Overlayers by in Situ Small- and Wide-Angle X-ray Scattering

    Energy Technology Data Exchange (ETDEWEB)

    Li, Tao; Karwal, Saurabh; Aoun, Bachir; Zhao, Haiyan; Ren, Yang; Canlas, Christian P.; Elam, Jeffrey W.; Winans, Randall E.

    2016-10-11

    In this work, we explore the pore structure of overcoated materials by in situ synchrotron small- and wide-angle X-ray scattering (SAXS)/(WAXS). Thin films of aluminum oxide (Al2O3) and titanium dioxide (TiO2) with thicknesses of 4.9 and 2.5 nm, respectively, are prepared by atomic layer deposition (ALD) on non-porous nanoparticles. In situ X-ray measurements reveal that porosity is induced in the ALD films by annealing the samples at high temperature. Moreover, this pore formation can be attributed to densification resulting from an amorphous to crystalline phase transition of the ALD films as confirmed by high resolution X-ray diffraction (XRD) and pair distribution function (PDF). Simultaneous SAXS/WAXS results not only show the porosity is formed by the phase transition but also that the pore size increases with temperature.

  13. Exploring Pore Formation of Atomic Layer-Deposited Overlayers by in Situ Small- and Wide-Angle X-ray Scattering

    Energy Technology Data Exchange (ETDEWEB)

    Li, Tao; Karwal, Saurabh; Aoun, Bachir; Zhao, Haiyan; Ren, Yang; Canlas, Christian P.; Elam, Jeffrey W.; Winans, Randall E.

    2016-10-11

    In this work, we explore the pore structure of overcoated materials by in situ synchrotron small- and wide-angle X-ray scattering (SAXS)/(WAXS). Thin films of aluminum oxide (Al2O3) and titanium dioxide (TiO2) with thicknesses of 4.9 and 2.5 nm, respectively, are prepared by atomic layer deposition (ALD) on non-porous nanoparticles. In situ X-ray measurements reveal that porosity is induced in the ALD films by annealing the samples at high temperature. Moreover, this pore formation can be attributed to densification resulting from an amorphous to crystalline phase transition of the ALD films as confirmed by high resolution X-ray diffraction (XRD) and pair distribution function (PDF). Simultaneous SAXS/WAXS results not only show that the porosity is formed by this phase transition but also that the pore size increases with temperature.

  14. Small angle neutron scattering study of the magnetic flux-line lattice in single crystal 2H-NbSe2

    DEFF Research Database (Denmark)

    Gammel, P.L.; Huse, D.A.; Kleiman, R.N.

    1994-01-01

    We report on a small angle neutron scattering study of the flux-line lattice in single crystal 2H-NbSe2. As the magnetic field is tilted away from the crystalline c axis, we find distortions in the flux lattice as would be expected for a mass anisotropy GAMMA = 10.1 +/- 0.9. However, we find...... that the lattice orientation is in disagreement with the predictions of both anisotropic London and Ginzburg-Landau theories. The observed flux lattice orientation remains pinned to that of the crystal lattice for the field orientations studied. The form factors can be quantitatively understood within...... the framework of Ginzburg-Landau corrections to the London equations....

  15. Guanosine Quadruplexes in Solution: A Small-Angle X-Ray Scattering Analysis of Temperature Effects on Self-Assembling of Deoxyguanosine Monophosphate

    Directory of Open Access Journals (Sweden)

    P. Mariani

    2010-01-01

    Full Text Available We investigated quadruplex formation in aqueous solutions of 2′-deoxyriboguanosine 5′-monophosphate, d(pG, which takes place in the absence of the covalent axial backbone. A series of in-solution small angle X-ray scattering experiments on d(pG have been performed as a function of temperature in the absence of excess salt, at a concentration just above the critical one at which self-assembling occurs. A global fit approach has been used to derive composition and size distribution of the scattering particles as a function of temperature. The obtained results give thermodynamical justification for the observed phase-behavior, indicating that octamer formation is essential for quadruplex elongation. Our investigation shows that d(pG quadruplexes are very suitable to assess the potential of G-quadruplex formation and to study the self-assembling thermodynamics.

  16. 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.

  17. 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.

  18. Probing He bubbles in naturally aged and annealed δ-Pu alloys using ultra-small-angle x-ray scattering

    Energy Technology Data Exchange (ETDEWEB)

    Jeffries, J. R.; Hammons, J. A.; Willey, T. M.; Wall, M. A.; Ruddle, D.; Ilavsky, J.; Allen, P. G.; van Buuren, T.

    2018-01-01

    The self-irradiation of Pu alloys generates He that is trapped within the metal matrix in the form of He bubbles. The distribution of these He bubbles in δ-phase Pu-Ga alloys exhibits a peak near a radius of 0.7 nm, and this size is remarkably stable as function of time. When annealed, the He bubbles in δ-Pu alloys grow, coarsening the distribution. However, the magnitude of this coarsening is uncertain, as different experimental methods reveal bubbles that differ by at least one order of magnitude. Small-angle x-ray scattering results, which can probe a wide range of bubble sizes, imply only a mild coarsening of the He bubble distribution for an annealing treatment of 425 °C for 24 h, and analysis of the He bubble content suggests that He is actually lost from the bubbles with annealing.

  19. Analysis of liquid crystalline nanoparticles by small angle X-ray diffraction: evaluation of drug and pharmaceutical additives influence on the internal structure.

    Science.gov (United States)

    Rossetti, Fábia Cristina; Fantini, Márcia C A; Carollo, Aline Regina H; Tedesco, Antônio Cláudio; Bentley, Maria Vitória Lopes Badra

    2011-07-01

    The goal of this work was to study the liquid crystalline structure of a nanodispersion delivery system intended to be used in photodynamic therapy after loading with photosensitizers (PSs) and additives such as preservatives and thickening polymers. Polarized light microscopy and light scattering were performed on a standard nanodispersion in order to determine the anisotropy of the liquid crystalline structure and the mean diameter of the nanoparticles, respectively. Small angle X-ray diffraction (SAXRD) was used to verify the influence of drug loading and additives on the liquid crystalline structure of the nanodispersions. The samples, before and after the addition of PSs and additives, were stable over 90 days, as verified by dynamic light scattering. SAXRD revealed that despite the alteration observed in some of the samples analyzed in the presence of photosensitizing drugs and additives, the hexagonal phase still remained in the crystalline phase. Copyright © 2011 Wiley-Liss, Inc. and the American Pharmacists Association

  20. 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 X......-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...... of symmetry Im3m to an internal inverted-type cubic phase of symmetry Pn3m was detected. The combination of microfluidics with X-ray techniques opens the door to the investigation of early dynamic structural transitions, which is not possible with conventional techniques such as glass flow cells...

  1. Small-angle X-ray scattering tensor tomography: model of the three-dimensional reciprocal-space map, reconstruction algorithm and angular sampling requirements.

    Science.gov (United States)

    Liebi, Marianne; Georgiadis, Marios; Kohlbrecher, Joachim; Holler, Mirko; Raabe, Jörg; Usov, Ivan; Menzel, Andreas; Schneider, Philipp; Bunk, Oliver; Guizar-Sicairos, Manuel

    2018-01-01

    Small-angle X-ray scattering tensor tomography, which allows reconstruction of the local three-dimensional reciprocal-space map within a three-dimensional sample as introduced by Liebi et al. [Nature (2015), 527, 349-352], is described in more detail with regard to the mathematical framework and the optimization algorithm. For the case of trabecular bone samples from vertebrae it is shown that the model of the three-dimensional reciprocal-space map using spherical harmonics can adequately describe the measured data. The method enables the determination of nanostructure orientation and degree of orientation as demonstrated previously in a single momentum transfer q range. This article presents a reconstruction of the complete reciprocal-space map for the case of bone over extended ranges of q. In addition, it is shown that uniform angular sampling and advanced regularization strategies help to reduce the amount of data required.

  2. Note: Comparison of grazing incidence small angle x-ray scattering of a titania sponge structure at the beamlines BW4 (DORIS III) and P03 (PETRA III)

    Energy Technology Data Exchange (ETDEWEB)

    Rawolle, M.; Koerstgens, V.; Ruderer, M. A.; Metwalli, E.; Guo, S.; Mueller-Buschbaum, P. [Lehrstuhl fuer Funktionelle Materialien, Physik-Department, Technische Universitaet Muenchen, James-Franck-Str. 1, 85748 Garching (Germany); Herzog, G.; Benecke, G.; Schwartzkopf, M.; Buffet, A.; Perlich, J.; Roth, S. V. [HASYLAB at DESY, Notkestr. 85, 22607 Hamburg (Germany)

    2012-10-15

    Grazing incidence small angle x-ray scattering (GISAXS) is a powerful technique for morphology investigation of nanostructured thin films. GISAXS measurements at the newly installed P03 beamline at the storage ring PETRA III in Hamburg, Germany, are compared to the GISAXS data from the beamline BW4 at the storage ring DORIS III, which had been used extensively for GISAXS investigations in the past. As an example, a titania thin film sponge structure is investigated. Compared to BW4, at beamline P03 the resolution of larger structures is slightly improved and a higher incident flux leads to a factor of 750 in scattered intensity. Therefore, the acquisition time in GISAXS geometry is reduced significantly at beamline P03.

  3. Small-angle neutron scattering instrument of Institute for Solid State Physics, the Univeristy of Tokyo (SANS-U) and its application to biology

    Energy Technology Data Exchange (ETDEWEB)

    Ito, Yuji; Imai, Masayuki; Takahashi, Shiro [Univ. of Tokyo, Tokai Naka Ibaraki (Japan)

    1994-12-31

    A small-angle neutron spectrometer (SANS-U) suitable for the study of mesoscopic structure in the field of polymer chemistry and biology, has been constructed at the guide hall of JRR-3M reactor at the Japan Atomic Energy Research Institute. The instrument is 32m long and utilizes a mechanical velocity selector and pinhole collimation to provide a continuous beam with variable wavelength in the range from 5 to 10{Angstrom}. The neutron detector is a 65 x 65cm{sup 2} 2D position sensitive proportional counter. The practical Q range of SANS-U is 0.0008 to 0.45{Angstrom}{sup -1}. The design, characteristics and performance of SANS-U are described with some biological studies using SANS-U.

  4. Small-angle neutron scattering study of the ultrastructure of chloroplast thylakoid membranes - Periodicity and structural flexibility of the stroma lamellae

    DEFF Research Database (Denmark)

    Posselt, Dorthe; Nagy, Gergely; Kirkensgaard, Jacob J. K.

    2012-01-01

    The multilamellar organization of freshly isolated spinach and pea chloroplast thylakoid membranes was studied using small-angle neutron scattering. A broad peak at similar to 0.02 angstrom(-1) is ascribed to diffraction from domains of ordered, unappressed stroma lamellae, revealing a repeat...... distance of 294 angstrom +/- 7 angstrom in spinach and 345 angstrom +/- 11 angstrom in pea. The peak position and hence the repeat distance of stroma lamellae is strongly dependent on the osmolarity and the ionic strength of the suspension medium, as demonstrated by varying the sorbitol and the Mg......++-concentration in the sample. For pea thylakoid membranes, we show that the repeat distance decreases when illuminating the sample with white light, in accordance with our earlier results on spinach, also regarding the observation that addition of an uncoupler prohibits the light-induced structural changes, a strong...

  5. Characterization of white poplar and eucalyptus after ionic liquid pretreatment as a function of biomass loading using X-ray diffraction and small angle neutron scattering

    Energy Technology Data Exchange (ETDEWEB)

    Yuan, Xueming [Beijing Univ. of Chemical Technology (China); Duan, Yonghao [Beijing Univ. of Chemical Technology (China); He, Lilin [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Singh, Seema [Sandia National Lab. (SNL-CA), Livermore, CA (United States); Joint BioEnergy Inst. (JBEI), Emeryville, CA (United States); Simmons, Blake [Joint BioEnergy Inst. (JBEI), Emeryville, CA (United States); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Cheng, Gang [Beijing Univ. of Chemical Technology (China); Joint BioEnergy Inst. (JBEI), Emeryville, CA (United States); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2017-02-08

    A systematic study was done to understand interactions among biomass loading during ionic liquid (IL) pretreatment, biomass type and biomass structures. White poplar and eucalyptus samples were pretreated using 1-ethyl-3-methylimidazolium acetate (EmimOAc) at 110 °C for 3 h at biomass loadings of 5, 10, 15, 20 and 25 wt%. All of the samples were chemically characterized and tested for enzymatic hydrolysis. Physical structures including biomass crystallinity and porosity were measured by X-ray diffraction (XRD) and small angle neutron scattering (SANS), respectively. SANS detected pores of radii ranging from ~25 to 625 Å, enabling assessment of contributions of pores with different sizes to increased porosity after pretreatment. Contrasting dependences of sugar conversion on white poplar and eucalyptus as a function of biomass loading were observed and cellulose crystalline structure was found to play an important role.

  6. Global small-angle X-ray scattering data analysis for multilamellar vesicles: the evolution of the scattering density profile model.

    Science.gov (United States)

    Heftberger, Peter; Kollmitzer, Benjamin; Heberle, Frederick A; Pan, Jianjun; Rappolt, Michael; Amenitsch, Heinz; Kučerka, Norbert; Katsaras, John; Pabst, Georg

    2014-02-01

    The highly successful scattering density profile (SDP) model, used to jointly analyze small-angle X-ray and neutron scattering data from unilamellar vesicles, has been adapted for use with data from fully hydrated, liquid crystalline multilamellar vesicles (MLVs). Using a genetic algorithm, this new method is capable of providing high-resolution structural information, as well as determining bilayer elastic bending fluctuations from standalone X-ray data. Structural parameters such as bilayer thickness and area per lipid were determined for a series of saturated and unsaturated lipids, as well as binary mixtures with cholesterol. The results are in good agreement with previously reported SDP data, which used both neutron and X-ray data. The inclusion of deuterated and non-deuterated MLV neutron data in the analysis improved the lipid backbone information but did not improve, within experimental error, the structural data regarding bilayer thickness and area per lipid.

  7. 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......-throughs allows different sample environments to be mounted. This station is used for measurements on weakly scattering proteins in solutions and also for colloids, polymers and other nanoscale structures. A special application supported by the beamline is the effort to establish a micro-fluidic sample...... environment for structural analysis of samples that are only available in limited quantities. Overall, this work demonstrates how a cost-effective SAXS station can be constructed on a multipurpose beamline....

  8. Using macromolecular-crystallography beamline and microfluidic platform for small-angle diffraction studies of lipidic matrices for membrane-protein crystallization

    Science.gov (United States)

    Kondrashkina, E.; Khvostichenko, D. S.; Perry, S. L.; Von Osinski, J.; Kenis, P. J. A.; Brister, K.

    2013-03-01

    Macromolecular-crystallography (MX) beamlines routinely provide a possibility to change X-ray beam energy, focus the beam to a size of tens of microns, align a sample on a microdiffractometer using on-axis video microscope, and collect data with an area-detector positioned in three dimensions. These capabilities allow for running complementary measurements of small-angle X-ray scattering and diffraction (SAXS) at the same beamline with such additions to the standard MX setup as a vacuum path between the sample and the detector, a modified beam stop, and a custom sample cell. On the 21-ID-D MX beamline at the Advanced Photon Source we attach a vacuum flight tube to the area detector support and use the support motion for aligning a beam stop built into the rear end of the flight tube. At 8 KeV energy and 1 m sample-to-detector distance we can achieve a small-angle resolution of 0.01A-1 in the reciprocal space. Measuring SAXS with this setup, we have studied phase diagrams of lipidic mesophases used as matrices for membrane-protein crystallization. The outcome of crystallization trials is significantly affected by the structure of the lipidic mesophases, which is determined by the composition of the crystallization mixture. We use a microfluidic chip for the mesophase formulation and in situ SAXS data collection. Using the MX beamline and the microfluidic platform we have demonstrated the viability of the high-throughput SAXS studies facilitating screening of lipidic matrices for membrane-protein crystallization.

  9. Crystal Structures and Small-angle X-ray Scattering Analysis of UDP-galactopyranose Mutase from the Pathogenic Fungus Aspergillus fumigatus

    Energy Technology Data Exchange (ETDEWEB)

    Dhatwalia, Richa; Singh, Harkewal; Oppenheimer, Michelle; Karr, Dale B.; Nix, Jay C.; Sobrado, Pablo; Tanner, John J. (LBNL); (Missouri); (VPI)

    2015-10-15

    UDP-galactopyranose mutase (UGM) is a flavoenzyme that catalyzes the conversion of UDP-galactopyranose to UDP-galactofuranose, which is a central reaction in galactofuranose biosynthesis. Galactofuranose has never been found in humans but is an essential building block of the cell wall and extracellular matrix of many bacteria, fungi, and protozoa. The importance of UGM for the viability of many pathogens and its absence in humans make UGM a potential drug target. Here we report the first crystal structures and small-angle x-ray scattering data for UGM from the fungus Aspergillus fumigatus, the causative agent of aspergillosis. The structures reveal that Aspergillus UGM has several extra secondary and tertiary structural elements that are not found in bacterial UGMs yet are important for substrate recognition and oligomerization. Small-angle x-ray scattering data show that Aspergillus UGM forms a tetramer in solution, which is unprecedented for UGMs. The binding of UDP or the substrate induces profound conformational changes in the enzyme. Two loops on opposite sides of the active site move toward each other by over 10 {angstrom} to cover the substrate and create a closed active site. The degree of substrate-induced conformational change exceeds that of bacterial UGMs and is a direct consequence of the unique quaternary structure of Aspergillus UGM. Galactopyranose binds at the re face of the FAD isoalloxazine with the anomeric carbon atom poised for nucleophilic attack by the FAD N5 atom. The structural data provide new insight into substrate recognition and the catalytic mechanism and thus will aid inhibitor design.

  10. Operando Grazing Incidence Small-Angle X-ray Scattering/X-ray Diffraction of Model Ordered Mesoporous Lithium-Ion Battery Anodes.

    Science.gov (United States)

    Bhaway, Sarang M; Qiang, Zhe; Xia, Yanfeng; Xia, Xuhui; Lee, Byeongdu; Yager, Kevin G; Zhang, Lihua; Kisslinger, Kim; Chen, Yu-Ming; Liu, Kewei; Zhu, Yu; Vogt, Bryan D

    2017-02-28

    Emergent lithium-ion (Li+) batteries commonly rely on nanostructuring of the active electrode materials to decrease the Li+ ion diffusion path length and to accommodate the strains associated with the insertion and de-insertion of Li+, but in many cases these nanostructures evolve during electrochemical charging-discharging. This change in the nanostructure can adversely impact performance, and challenges remain regarding how to control these changes from the perspective of morphological design. In order to address these questions, operando grazing-incidence small-angle X-ray scattering and X-ray diffraction (GISAXS/GIXD) were used to assess the structural evolution of a family of model ordered mesoporous NiCo2O4 anode films during battery operation. The pore dimensions were systematically varied and appear to impact the stability of the ordered nanostructure during the cycling. For the anodes with small mesopores (≈9 nm), the ordered nanostructure collapses during the first two charge-discharge cycles, as determined from GISAXS. This collapse is accompanied by irreversible Li-ion insertion within the oxide framework, determined from GIXD and irreversible capacity loss. Conversely, anodes with larger ordered mesopores (17-28 nm) mostly maintained their nanostructure through the first two cycles with reversible Li-ion insertion. During the second cycle, there was a small additional deformation of the mesostructure. This preservation of the ordered structure lead to significant improvement in capacity retention during these first two cycles; however, a gradual loss in the ordered nanostructure from continuing deformation of the ordered structure during additional charge-discharge cycles leads to capacity decay in battery performance. These multiscale operando measurements provide insight into how changes at the atomic scale (lithium insertion and de-insertion) are translated to the nanostructure during battery operation. Moreover, small changes in the nanostructure

  11. Structure and dynamics of water in nonionic reverse micelles: a combined time-resolved infrared and small angle x-ray scattering study.

    Science.gov (United States)

    van der Loop, Tibert H; Panman, Matthijs R; Lotze, Stephan; Zhang, Jing; Vad, Thomas; Bakker, Huib J; Sager, Wiebke F C; Woutersen, Sander

    2012-07-28

    We study the structure and reorientation dynamics of nanometer-sized water droplets inside nonionic reverse micelles (water/Igepal-CO-520/cyclohexane) with time-resolved mid-infrared pump-probe spectroscopy and small angle x-ray scattering. In the time-resolved experiments, we probe the vibrational and orientational dynamics of the O-D bonds of dilute HDO:H(2)O mixtures in Igepal reverse micelles as a function of temperature and micelle size. We find that even small micelles contain a large fraction of water that reorients at the same rate as water in the bulk, which indicates that the polyethylene oxide chains of the surfactant do not penetrate into the water volume. We also observe that the confinement affects the reorientation dynamics of only the first hydration layer. From the temperature dependent surface-water dynamics, we estimate an activation enthalpy for reorientation of 45 ± 9 kJ mol(-1) (11 ± 2 kcal mol(-1)), which is close to the activation energy of the reorientation of water molecules in ice.

  12. Toward a new lower limit for the minimum scattering vector on the very small angle neutron scattering spectrometer at Laboratoire Leon Brillouin

    Energy Technology Data Exchange (ETDEWEB)

    Brulet, A.; Thevenot, V.; Lairez, D.; Desert, S. [CEA Saclay, CEA-CNRS, UMR12, Lab Leon Brillouin, F-91191 Gif Sur Yvette (France); Lecommandoux, S.; Agut, W. [Univ Bordeaux 1, ENSCPB CNRS, Lab Chim Polymeres Organ, F-33607 Pessac (France); Armes, S.P.; Du, J. [Univ Sheffield, Dept Chem, Sheffield S3 7HF (United Kingdom)

    2008-07-01

    The main characteristics of the very small angle neutron scattering spectrometer (VSANS) under construction at the Laboratoire Leon Brillouin are a multibeam pinhole collimator converging onto an image plate detector. By combining tiny collimation (diaphragms of around 1 or 2 mm in diameter) with the small pixel size of the detector (0.15 * 0.15 mm), very high resolution measurements can be achieved. The resolution function of the instrument contains a contribution from gravity, which is reduced by the intermediate masks of the collimator. Owing to the relatively short length of the VSANS instrument (around 14 m), this effect remains weak, in good agreement with the predictions. With a prototype multibeam collimator, an incident wavelength of 0.9 nm and the detector located at 6 m from the sample, it is possible to access q values as low as 4 * 10{sup -3} nm{sup -1} with very high q resolution. Promising preliminary experiments with high q resolution are reported, which open up new fields to the SANS technique. (authors)

  13. (1)H NMR and small-angle neutron scattering investigation of the structure and solubilization behavior of three-layer nanoparticles.

    Science.gov (United States)

    Kríz, Jaroslav; Plestil, Josef; Pospísil, Herman; Kadlec, Petr; Konák, Cestmír; Almásy, László; Kuklin, Alexander I

    2004-12-07

    Three-layer nanoparticles were prepared by radiation-induced polymerization of 1-10 g/L of methyl methacrylate dissolved in a 0.1 wt % D(2)O solution of polystyrene-poly(methacrylic acid) (PS-PMA) micelles. According to NMR and small-angle neutron scattering (SANS), most of the poly(methyl methacrylate) (PMMA) is adsorbed at the core-shell interface of the particles. A small fraction of shorter PMMA probably sticks to outer parts of the PMA chains. The absorption kinetics and equilibria of benzene and chloroform were studied by NMR and SANS time-resolved experiments. The diffusion front in the PS core is very narrow but quite broad in the PMMA sheet suggesting, thus, a less compact state of PMMA. According to SANS, the diffusion kinetics is almost independent of the PMMA sheet thickness. In contrast to it, the absorption capacity, reflected by both SANS and NMR, increases markedly with the PMMA content in the particle. The maximum amount of solubilized compound depends on its positive interaction with PMMA (expressed by the chi parameter) but is restricted by the growing interface tension between swollen PMMA and D(2)O. In accordance with this conclusion, a particle saturated with benzene can absorb chloroform only at the expense of a part of benzene expelled into the surrounding medium and vice versa. Starting with 10 g PMMA/L (10 times the weight of the original micelles), the particles become unstable when being swollen with a good solvent.

  14. Quantitative Correlation between Viscosity of Concentrated MAb Solutions and Particle Size Parameters Obtained from Small-Angle X-ray Scattering.

    Science.gov (United States)

    Fukuda, Masakazu; Moriyama, Chifumi; Yamazaki, Tadao; Imaeda, Yoshimi; Koga, Akiko

    2015-12-01

    To investigate the relationship between viscosity of concentrated MAb solutions and particle size parameters obtained from small-angle X-ray scattering (SAXS). The viscosity of three MAb solutions (MAb1, MAb2, and MAb3; 40-200 mg/mL) was measured by electromagnetically spinning viscometer. The protein interactions of MAb solutions (at 60 mg/mL) was evaluated by SAXS. The phase behavior of 60 mg/mL MAb solutions in a low-salt buffer was observed after 1 week storage at 25°C. The MAb1 solutions exhibited the highest viscosity among the three MAbs in the buffer containing 50 mM NaCl. Viscosity of MAb1 solutions decreased with increasing temperature, increasing salt concentration, and addition of amino acids. Viscosity of MAb1 solutions was lowest in the buffer containing histidine, arginine, and aspartic acid. Particle size parameters obtained from SAXS measurements correlated very well with the viscosity of MAb solutions at 200 mg/mL. MAb1 exhibited liquid-liquid phase separation at a low salt concentration. Simultaneous addition of basic and acidic amino acids effectively suppressed intermolecular attractive interactions and decreased viscosity of MAb1 solutions. SAXS can be performed using a small volume of samples; therefore, the particle size parameters obtained from SAXS at intermediate protein concentration could be used to screen for low viscosity antibodies in the early development stage.

  15. New insights into nucleation. Pressure trace measurements and the first small angle X-ray scattering experiments in a supersonic laval nozzle

    Energy Technology Data Exchange (ETDEWEB)

    Ghosh, D.

    2007-07-01

    Homogeneous nucleation rates of the n-alcohols and the n-alkanes have been determined by combining information from two sets of supersonic Laval nozzle expansion experiments under identical conditions. The nucleation rates J=N/{delta}t{sub Jmax} for the n-alcohols are in the range of 1.10{sup 17}Small Angle X-ray Scattering experiments are conducted to determine the particle number density for both substance classes. Particle number densities in the range of 1.10{sup 12}

  16. Monitoring early stages of silver particle formation in a polymer solution by in situ and time resolved small angle X-ray scattering

    Science.gov (United States)

    Campi, Gaetano; Mari, Alessandra; Amenitsch, Heinz; Pifferi, Augusto; Cannas, Carla; Suber, Lorenza

    2010-11-01

    Silver particles have been prepared by reduction of silver nitrate with ascorbic acid in acidic aqueous solution containing a low concentration of a commercial polynaphthalene sulfonate polymer (Daxad 19) as dispersant agent. The reduction has been induced and controlled by the slow addition of ascorbic acid at a fixed rate; in this way, we were able to monitor the formation of a silver crystalline colloidal dispersion by in situ and time resolved Small Angle X-ray Scattering measurements. Modeling the scattering intensity with interacting spherical particles in a polymer-Ag like-fractal template allowed us to distinguish different stages involving liquid-like ordered cluster nucleation, cluster growth up to primary particle formation and particle coalescence. Between primary particle formation and particle coalescence, we observed the occurrence of a transient phase of core-shell type structures having primary particles as stable cores in expanding shells built by the organic polymer. We discuss these results in a twofold perspective pertaining both to technology, relative to controlled fabrication of metal nanoparticles and to basic chemical physics, dealing with non standard stepwise crystallization from solutions.Silver particles have been prepared by reduction of silver nitrate with ascorbic acid in acidic aqueous solution containing a low concentration of a commercial polynaphthalene sulfonate polymer (Daxad 19) as dispersant agent. The reduction has been induced and controlled by the slow addition of ascorbic acid at a fixed rate; in this way, we were able to monitor the formation of a silver crystalline colloidal dispersion by in situ and time resolved Small Angle X-ray Scattering measurements. Modeling the scattering intensity with interacting spherical particles in a polymer-Ag like-fractal template allowed us to distinguish different stages involving liquid-like ordered cluster nucleation, cluster growth up to primary particle formation and particle

  17. Characterization of the Decaheme c-Type Cytochrome OmcA in Solution and on Hematite Surfaces by Small Angle X-Ray Scattering and Neutron Reflectometry

    Science.gov (United States)

    Johs, A.; Shi, L.; Droubay, T.; Ankner, J.F.; Liang, L.

    2010-01-01

    Abstract The outer membrane protein OmcA is an 85 kDa decaheme c-type cytochrome located on the surface of the dissimilatory metal-reducing bacterium Shewanella oneidensis MR-1. It is assumed to mediate shuttling of electrons to extracellular acceptors that include solid metal oxides such as hematite (α-Fe2O3). No information is yet available concerning OmcA structure in physiologically relevant conditions such as aqueous environments. We purified OmcA and characterized its solution structure by small angle x-ray scattering (SAXS), and its interaction at the hematite-water interface by neutron reflectometry. SAXS showed that OmcA is a monomer that adopts a flat ellipsoidal shape with an overall dimension of 34 × 90 × 65 Å3. To our knowledge, we obtained the first direct evidence that OmcA undergoes a redox state-dependent conformational change in solution whereby reduction decreases the overall length of OmcA by ∼7 Å (the maximum dimension was 96 Å for oxidized OmcA, and 89 Å for NADH and dithionite-reduced OmcA). OmcA was also found to physically interact with electron shuttle molecules such as flavin mononucleotide, resulting in the formation of high-molecular-weight assemblies. Neutron reflectometry showed that OmcA forms a well-defined monomolecular layer on hematite surfaces, where it assumes an orientation that maximizes its contact area with the mineral surface. These novel insights into the molecular structure of OmcA in solution, and its interaction with insoluble hematite and small organic ligands, demonstrate the fundamental structural bases underlying OmcA's role in mediating redox processes. PMID:20550916

  18. Analysis of InGaN nanodots grown by droplet heteroepitaxy using grazing incidence small-angle X-ray scattering and electron microscopy

    Science.gov (United States)

    Woodward, J. M.; Nikiforov, A. Yu.; Ludwig, K. F.; Moustakas, T. D.

    2017-08-01

    We present a detailed structural investigation of self-assembled indium gallium nitride nanodots grown on c-plane aluminum nitride templates by the droplet heteroepitaxy technique in a plasma-assisted molecular beam epitaxy reactor. Various growth parameters, including the total coverage of the metal species, relative and total metal effusion fluxes, and nitridation temperature were investigated. Analyses of in situ reflection high-energy electron diffraction patterns and comparison with simulations showed that the resulting crystal structure was a mixture of wurtzite and twinned zinc blende phases, with the zinc blende phase increasingly dominant for lower metal coverages and lower nitridation temperatures, and the wurtzite phase increasingly dominant for higher nitridation temperature. Studies by field emission scanning electron microscopy and atomic force microscopy revealed that the nanodots exhibit trimodal size distributions, with the dot morphologies of the intermediate size mode often resembling aggregations of distinct clusters. Nanodots grown at higher nitridation temperatures had larger inter-dot spacings, with hexagonal in-plane ordering observable at a sufficiently high temperature. Using grazing incidence small angle X-ray scattering, we determined the nanodots to be approximately truncated cone shaped, and extracted the mean radius, height, and inter-dot distance for each distribution. Microstructural investigations of the nanodots by cross-sectional transmission electron microscopy indicated that the majority of the dots were formed in dislocation-free regions, and confirmed that the intermediate size dots were approximately truncated cone shaped and consisted of both zinc blende and wurtzite regions. Mapping of the elemental distributions by energy dispersive X-ray spectroscopy in scanning transmission electron microscopy mode indicated highly nonuniform indium distributions within both small and intermediate size dots which are potentially

  19. Structural analysis of lipocalin-type prostaglandin D synthase complexed with biliverdin by small-angle X-ray scattering and multi-dimensional NMR.

    Science.gov (United States)

    Miyamoto, Yuya; Nishimura, Shigenori; Inoue, Katsuaki; Shimamoto, Shigeru; Yoshida, Takuya; Fukuhara, Ayano; Yamada, Mao; Urade, Yoshihiro; Yagi, Naoto; Ohkubo, Tadayasu; Inui, Takashi

    2010-02-01

    Lipocalin-type prostaglandin D synthase (L-PGDS) acts as both a PGD(2) synthase and an extracellular transporter for small lipophilic molecules. From a series of biochemical studies, it has been found that L-PGDS has an ability to bind a variety of lipophilic ligands such as biliverdin, bilirubin and retinoids in vitro. Therefore, we considered that it is necessary to clarify the molecular structure of L-PGDS upon binding ligand in order to understand the physiological relevance of L-PGDS as a transporter protein. We investigated a molecular structure of L-PGDS/biliverdin complex by small-angle X-ray scattering (SAXS) and multi-dimensional NMR measurements, and characterized the binding mechanism in detail. SAXS measurements revealed that L-PGDS has a globular shape and becomes compact by 1.3A in radius of gyration on binding biliverdin. NMR experiments revealed that L-PGDS possessed an eight-stranded antiparallel beta-barrel forming a central cavity. Upon the titration with biliverdin, some cross-peaks for residues surrounding the cavity and EF-loop and H2-helix above the beta-barrel shifted, and the intensity of other cross-peaks decreased with signal broadenings in (1)H-(15)N heteronuclear single quantum coherence spectra. These results demonstrate that L-PGDS holds biliverdin within the beta-barrel, and the conformation of the loop regions above the beta-barrel changes upon binding biliverdin. Through such a conformational change, the whole molecule of L-PGDS becomes compact.

  20. Structure factor of blends of solvent-free nanoparticle–organic hybrid materials: density-functional theory and small angle X-ray scattering

    KAUST Repository

    Yu, Hsiu-Yu

    2014-09-15

    © the Partner Organisations 2014. We investigate the static structure factor S(q) of solvent-free nanoparticle-organic hybrid materials consisting of silica nanocores and space-filling polyethylene glycol coronas using a density-functional theory and small angle X-ray scattering measurements. The theory considers a bidisperse suspension of hard spheres with different radii and tethered bead-spring oligomers with different grafting densities to approximate the polydispersity effects in experiments. The experimental systems studied include pure samples with different silica core volume fractions and the associated mean corona grafting densities, and blends with different mixing ratios of the pure samples, in order to introduce varying polydispersity of corona grafting density. Our scattering experiments and theory show that, compared to the hard-sphere suspension with the same core volume fraction, S(q) for pure samples exhibit both substantially smaller values at small q and stronger particle correlations corresponding to a larger effective hard core at large q, indicating that the tethered incompressible oligomers enforce a more uniform particle distribution, and the densely grafted brush gives rise to an additional exclusionary effect between the nanoparticles. According to the theory, polydispersity in the oligomer grafting density controls the deviation of S(q) from the monodisperse system at smaller q, and the interplay of the enhanced effective core size and the entropic attraction among the particles is responsible for complex variations in the particle correlations at larger q. The successful comparison between the predictions and the measurements for the blends further suggests that S(q) can be used to assess the uniformity of grafting density in polymer-grafted nanoparticle materials. This journal is

  1. Modification of Spherical Polyelectrolyte Brushes by Layer-by-Layer Self-Assembly as Observed by Small Angle X-ray Scattering

    Directory of Open Access Journals (Sweden)

    Yuchuan Tian

    2016-04-01

    Full Text Available Multilayer modified spherical polyelectrolyte brushes were prepared through alternate deposition of positively charged poly(allylamine hydrochloride (PAH and negatively charged poly-l-aspartic acid (PAsp onto negatively charged spherical poly(acrylic acid (PAA brushes (SPBs on a poly(styrene core. The charge reversal determined by the zeta potential indicated the success of layer-by-layer (LBL deposition. The change of the structure during the construction of multilayer modified SPBs was observed by small-angle X-ray scattering (SAXS. SAXS results indicated that some PAH chains were able to penetrate into the PAA brush for the PAA-PAH double-layer modified SPBs whereas part of the PAH moved towards the outer layer when the PAsp layer was loaded to form a PAA-PAH-PAsp triple-layer system. The multilayer modified SPBs were stable upon changing the pH (5 to 9 and ionic strength (1 to 100 mM. The triple-layer modified SPBs were more tolerated to high pH (even at 11 compared to the double-layer ones. SAXS is proved to be a powerful tool for studying the inner structure of multilayer modified SPBs, which can establish guidelines for the a range of potential applications of multilayer modified SPBs.

  2. Probing evaporation induced assembly across a drying colloidal droplet using in situ small-angle X-ray scattering at the synchrotron source.

    Science.gov (United States)

    Sen, D; Bahadur, J; Mazumder, S; Santoro, G; Yu, S; Roth, S V

    2014-03-14

    Colloidal particles in a tiny drying droplet are forced to assemble due to attractive capillary forces. Jamming of the particles throughout the droplet remains either isotropic or anisotropic depending upon the drying kinetics and the physicochemical environment. In this work, we explore the dynamical evolution of such an assembly process across a single evaporative droplet by in situ scanning small-angle scattering using a micro-focused X-ray beam at the synchrotron source. A methodology has been elucidated to differentiate quantitatively between the isotropic and the anisotropic jamming process. Switching of jamming behaviour depending on the initial particle volume fraction in the droplet has been demonstrated. Three distinct stages of assembly, associated with droplet shrinkage, have been revealed even during isotropic jamming. This is in contrast to the drying of a pure liquid droplet under diffusion limited evaporation. It has been established that such in situ scattering measurements can also be used to estimate the temporal evolutions of the viscosity of a drying suspension as well as the diffusivity of nanoparticles in a droplet.

  3. Interaction of the Full-length Bax Protein with Biomimetic Mitochondrial Liposomes: A Small-Angle Neutron Scattering and Fluorescence Study

    Energy Technology Data Exchange (ETDEWEB)

    Satsoura, D [McMaster University; Kucerka, Norbert [Canadian Neutron Beam Centre and Comelius University (Slovakia); Shivakumar, S [McMaster University; Pencer, J [Atomic Energy of Canada Limited, Chalk River Laboratories; Griffiths, C [McMaster University; Leber, B [McMaster University; Andrews, D.W [McMaster University; Katsaras, John [ORNL; Fradin, C [McMaster University

    2012-01-01

    In response to apoptotic stimuli, the pro-apoptotic protein Bax inserts in the outer mitochondrial membrane, resulting in the formation of pores and the release of several mitochondrial components, and sealing the cell's fate. To study the binding of Bax to membranes, we used an in vitro system consisting of 50 nm diameter liposomes prepared with a lipid composition mimicking that of mitochondrial membranes in which recombinant purified full-length Bax was inserted via activation with purified tBid. We detected the association of the protein with the membrane using fluorescence fluctuation methods, and found that it could well be described by an equilibrium between soluble and membrane-bound Bax and that at a high protein-toliposome ratio the binding seemed to saturate at about 15 Bax proteins per 50 nm diameter liposome. We then obtained structural data for samples in this saturated binding regime using small-angle neutron scattering under different contrast matching conditions. Utilizing a simple model to fit the neutron data, we observed that a significant amount of the protein mass protrudes above the membrane, in contrast to the conjecture that all of the membrane-associated Bax states are umbrella-like. Upon protein binding, we also observed a thinning of the lipid bilayer accompanied by an increase in liposome radius, an effect reminiscent of the action of antimicrobial peptides on membranes.

  4. 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.

  5. Positron Annihilation Spectroscopy and Small Angle Neutron Scattering Characterization of the Effect of Mn on the Nanostructural Features formed in Irradiated Fe-Cu-Mn Alloys

    Energy Technology Data Exchange (ETDEWEB)

    Glade, S C; Wirth, B D; Asoka-Kumar, P; Odette, G R; Sterne, P A; Howell, R H

    2003-02-27

    The size, number density and composition of the nanometer defects responsible for the hardening and embrittlement in irradiated Fe-0.9wt.% Cu and Fe-0.9wt.% Cu-1.0wt% Mn model reactor pressure vessel alloys were measured using small angle neutron scattering and positron annihilation spectroscopy. These alloys were irradiated at 290 C to relatively low neutron fluences (E > 1 MeV, 6.0 x 10{sup 20} to 4.0 x 10{sup 21} n/m{sup 2}) in order to study the effect of manganese on the nucleation and growth of copper rich precipitates and secondary defect features. Copper rich precipitates were present in both alloys following irradiation. The Fe-Cu-Mn alloy had smaller precipitates and a larger number density of precipitates, suggesting Mn segregation at the iron matrix-precipitate interface which reduces the interfacial energy and in turn the driving force for coarsening. Mn also retards the precipitation kinetics and inhibits large vacancy cluster formation, suggesting a strong Mn-vacancy interaction which reduces radiation enhanced diffusion.

  6. Small-angle neutron scattering study of the short-range organization of dispersed CsNi[Cr(CN){sub 6}] nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Ridier, Karl; Gillon, Béatrice; André, Gilles; Chaboussant, Grégory, E-mail: gregory.chaboussant@cea.fr [Laboratoire Léon Brillouin, UMR12 CEA-CNRS, 91191 Gif-sur-Yvette (France); Catala, Laure; Mazérat, Sandra; Mallah, Talal [Institut de Chimie Moléculaire et des Matériaux d' Orsay, CNRS, Université Paris-Sud, 91405 Orsay (France)

    2015-09-21

    Prussian blue analogues magnetic nanoparticles (of radius R{sub 0} = 2.4–8.6 nm) embedded in PVP (polyvinylpyrrolidone) or CTA{sup +} (cetyltrimethylammonium) matrices have been studied using neutron diffraction and small angle neutron scattering (SANS) at several concentrations. For the most diluted particles in neutral PVP, the SANS signal is fully accounted for by a “single-particle” spherical form factor with no structural correlations between the nanoparticles and with radii comparable to those inferred from neutron diffraction. For higher concentration in PVP, structural correlations modify the SANS signal with the appearance of a structure factor peak, which is described using an effective “mean-field” model. A new length scale R{sup * }≈ 3R{sub 0}, corresponding to an effective repulsive interaction radius, is evidenced in PVP samples. In CTA{sup +}, electrostatic interactions play a crucial role and lead to a dense layer of CTA{sup +} around the nanoparticles, which considerably alter the SANS patterns as compared to PVP. The SANS data of nanoparticles in CTA{sup +} are best described by a core-shell model without visible inter-particle structure factor.

  7. Steady and out-of-equilibrium phase diagram of a complex fluid at the nanolitre scale: combining microevaporation, confocal Raman imaging and small angle X-ray scattering.

    Science.gov (United States)

    Daubersies, Laure; Leng, Jacques; Salmon, Jean-Baptiste

    2013-03-07

    We engineered specific microfluidic devices based on the pervaporation of water through a PDMS membrane, to formulate continuous and steady concentration gradients of a binary aqueous molecular mixture at the nanolitre scale. In the case of a model complex fluid (a triblock copolymer solution), we demonstrate that such a steady gradient crosses the phase diagram from pure water up to a succession of highly viscous mesophases. We then performed in situ spatially resolved measurements (confocal spectroscopy and small-angle X-ray scattering) to quantitatively measure the concentration profile and to determine the microstructure of the different textures. Within a single microfluidic channel, we thus screen quantitatively and continuously the phase diagram of a complex fluid. Beside, as such a gradient corresponds to an out-of-equilibrium regime, we also extract from the concentration measurement a precise estimate of the collective diffusion coefficient of the mixture as a function of the concentration. In the present case of the triblock copolymer, this transport coefficient features discontinuities at some phase boundaries, which have never been observed before.

  8. Structure of Fucoidan from Brown Seaweed Turbinaria ornata as Studied by Electrospray Ionization Mass Spectrometry (ESIMS) and Small Angle X-ray Scattering (SAXS) Techniques

    Science.gov (United States)

    Thanh, Thuy Thi Thu; Tran, Van Thi Thanh; Yuguchi, Yoshiaki; Bui, Ly Minh; Nguyen, Tai Tien

    2013-01-01

    The purpose of this study is to elucidate both the chemical and conformational structure of an unfractionated fucoidan extracted from brown seaweed Turbinaria ornata collected at Nha-trang bay, Vietnam. Electrospray ionization mass spectrometry (ESI-MS) was used for determining the chemical structure and small angle X-ray scattering (SAXS) provided conformational of the structure at the molecular level. The results showed that the fucoidan has a sulfate content of 25.6% and is mainly composed of fucose and galactose residues (Fuc:Gal ≈ 3:1). ESIMS analysis suggested that the fucoidan has a backbone of 3-linked α-l-Fucp residues with branches, →4)-Galp(1→ at C-4 of the fucan chain. Sulfate groups are attached mostly at C-2 and sometimes at C-4 of both fucose and galactose residues. A molecular model of the fucoidan was built based on obtained chemical structure and scattering curves estimated from molecular model and observed SAXS measurement were fitted. The results indicated that fucoidan under study has a rod-like bulky chain conformation. PMID:23857110

  9. Shape evolution with temperature of a thermotolerant protein (PeaT1) in solution detected by small angle X-ray scattering.

    Science.gov (United States)

    Xing, Xueqing; Liu, Quan; Wang, Wei; Zhang, Kunhao; Li, Tang; Cai, Quan; Mo, Guang; Cheng, Weidong; Wang, Dehong; Gong, Yu; Chen, Zhongjun; Qiu, Dewen; Wu, Zhonghua

    2013-01-01

    The protein elicitor from Alternaria tenuissima (PeaT1) presented excellent thermotolerance and potential application in agriculture as a pesticide. Previous synchrotron radiation circular dichroism study demonstrated that the secondary structures in PeaT1 protein are reversible with temperature change. To further clarify the mechanism of its thermotolerance, synchrotron radiation small angle x-ray scattering (SAXS) technique was used to study the shape change of PeaT1 protein with temperature in this article. Ab initio structure restorations based on the SAXS data revealed that PeaT1 protein has a prolate shape with a P₂ symmetry axis along the prolate anisometric direction. With temperature increase, a gooseneck vase-like (25°C), to jug-like (55°C), then to oval (85°C) shape change can be found, and these shape changes are also approximately reversible with temperature decrease. PeaT1 protein contains two homogenous molecules, and each of them consists of F, NAC, T, and UBA domains. The structures of the four domains were predicted. Simulated annealing algorithm was used to superimpose the domain structures onto the SAXS shapes. It was found that all the structural domains have position rotation and translation with temperature change, but the NAC domains are relatively stable, playing a role of frame. This shape change information provides clues for further exploring its biological function and application. Copyright © 2012 Wiley Periodicals, Inc.

  10. 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.

  11. The location of coenzyme Q10 in phospholipid membranes made of POPE: a small-angle synchrotron X-ray diffraction study.

    Science.gov (United States)

    Wollstein, Christoph; Winterhalter, Mathias; Funari, Sérgio S

    2015-07-01

    The location of coenzyme Q10 (Q10) inside the inner mitochondrial membrane is a topic of research aiming at a deeper understanding of the function of the mitochondrial respiratory chain. We investigated the location of Q10 inside model membranes made of 1-palmitoyl-2-oleoyl-phosphatidylethanolamine by means of small-angle synchrotron X-ray diffraction. Q10, which stands for ubiquinone-10 (UQ) or ubihydroquinone-10 (UH), did not remarkably influence the main phase transition temperature, but significantly decreased the lamellar-inverse hexagonal phase transition temperature (T(h)). The effect of UH on T(h) was stronger than the effect of UQ and the effect of liquid Q10 on T(h) was stronger than the effect of crystalline Q10. In the presence of Q10, the lattice parameters of the lamellar phases remained unchanged, whereas the H II lattice parameter was clearly influenced: While UQ had an increasing effect, UH had a decreasing effect. Furthermore, Q10 prevented the formation of cubic phases. The results give new evidence that the headgroup of Q10 is distant from the center of the membrane, which might be important for the function of the mitochondrial respiratory chain.

  12. Core–Shell Structure of Monodisperse Poly(ethylene glycol)-Grafted Iron Oxide Nanoparticles Studied by Small-Angle X-ray Scattering

    Science.gov (United States)

    2015-01-01

    The promising applications of core–shell nanoparticles in the biological and medical field have been well investigated in recent years. One remaining challenge is the characterization of the structure of the hydrated polymer shell. Here we use small-angle X-ray scattering (SAXS) to investigate iron oxide core–poly(ethylene glycol) brush shell nanoparticles with extremely high polymer grafting density. It is shown that the shell density profile can be described by a scaling model that takes into account the locally very high grafting density near the core. A good fit to a constant density region followed by a star-polymer-like, monotonously decaying density profile is shown, which could help explain the unique colloidal properties of such densely grafted core–shell nanoparticles. SAXS experiments probing the thermally induced dehydration of the shell and the response to dilution confirmed that the observed features are associated with the brush and not attributed to structure factors from particle aggregates. We thereby demonstrate that the structure of monodisperse core–shell nanoparticles with dense solvated shells can be well studied with SAXS and that different density models can be distinguished from each other. PMID:26321792

  13. Core-Shell Structure of Monodisperse Poly(ethylene glycol)-Grafted Iron Oxide Nanoparticles Studied by Small-Angle X-ray Scattering.

    Science.gov (United States)

    Grünewald, Tilman A; Lassenberger, Andrea; van Oostrum, Peter D J; Rennhofer, Harald; Zirbs, Ronald; Capone, Barbara; Vonderhaid, Iris; Amenitsch, Heinz; Lichtenegger, Helga C; Reimhult, Erik

    2015-07-14

    The promising applications of core-shell nanoparticles in the biological and medical field have been well investigated in recent years. One remaining challenge is the characterization of the structure of the hydrated polymer shell. Here we use small-angle X-ray scattering (SAXS) to investigate iron oxide core-poly(ethylene glycol) brush shell nanoparticles with extremely high polymer grafting density. It is shown that the shell density profile can be described by a scaling model that takes into account the locally very high grafting density near the core. A good fit to a constant density region followed by a star-polymer-like, monotonously decaying density profile is shown, which could help explain the unique colloidal properties of such densely grafted core-shell nanoparticles. SAXS experiments probing the thermally induced dehydration of the shell and the response to dilution confirmed that the observed features are associated with the brush and not attributed to structure factors from particle aggregates. We thereby demonstrate that the structure of monodisperse core-shell nanoparticles with dense solvated shells can be well studied with SAXS and that different density models can be distinguished from each other.

  14. Observation of mesoscopic structure in NdBa sub 2 Cu sub 3 O sub 7 sub - subdelta by small-angle neutron scattering

    CERN Document Server

    Miyata, S; Suzuki, J I; Kuroda, K; Koshizuka, N

    2003-01-01

    In order to clarify the origin of the high critical current density (J sub c) of NdBa sub 2 Cu sub 3 O sub 7 sub - subdelta (Nd123), we investigated the inhomogeneities in this material by small-angle neutron scattering (SANS) experiments. As a result of numerical calculations, it was found that the anisotropic scattering patterns and radial intensity profiles can be explained by the existence of elliptic cylindrical objects of which the cylindrical axis is parallel to the crystallographic c-axis. Long and short elliptic axis lengths and the height of the elliptic cylinders in the high-J sub c sample are about 400, 200 and 100 nm, and those of the low-J sub c sample are about 200, 100 and 50 nm. Since these two samples have been heat-treated in different manners, it is suggested that sizes of the elliptic cylinders are affected by the heat treatments and this change in scale, as a result, increases or decreases the J sub c characteristics of the samples. (author)

  15. 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.

  16. 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.

  17. Characterization of Nanoparticles and Colloids in Aquatic Systems 1. Small Angle Neutron Scattering Investigations of Suwannee River Fulvic Acid Aggregates in Aqueous Solutions

    Energy Technology Data Exchange (ETDEWEB)

    Diallo, Mamadou S. [California Institute of Technology, Materials and Process Simulation Center, Beckman Institute 139-74 (United States)], E-mail: diallo@wag.caltech.edu; Glinka, Charles J. [National Institute of Standards and Technology, Center for Neutron Research (United States); Goddard, William A. [California Institute of Technology, Materials and Process Simulation Center, Beckman Institute 139-74 (United States); Johnson, James H. [Howard University, Department of Civil Engineering (United States)

    2005-10-15

    Fulvic acids (FA) and humic acids (HA) constitute 30-50% of dissolved organic matter in natural aquatic systems. In aqueous solutions, a commonly accepted view is that FA and HA exist as soluble macroligands at low concentration and as supramolecular aggregates at higher concentration. The size, shape and structure of these aggregates are still the subject of ongoing debate in the environmental chemistry literature. In this article, we use small angle neutron scattering (SANS) to assess the effects of solute concentration, solution pH and background electrolyte (NaCl) concentration on the structures of Suwannee River FA (SRFA) aggregates in D{sub 2}O. The qualitative features of the SANS curves and data analysis are not consistent with the view point that SRFA forms micelle-like aggregates as its concentration in aqueous solution increases. We find that SRFA forms fractal aggregates in D{sub 2}0 with size greater than 242 nm. The SRFA aggregates undergo a significant degree of restructuring in compactness as solution pH, solute concentration and NaCl concentration increase.

  18. Matchout deuterium labelling of proteins for small-angle neutron scattering studies using prokaryotic and eukaryotic expression systems and high cell-density cultures.

    Science.gov (United States)

    Dunne, O; Weidenhaupt, M; Callow, P; Martel, A; Moulin, M; Perkins, S J; Haertlein, M; Forsyth, V T

    2017-07-01

    Small-angle neutron scattering (SANS) is a powerful technique for the characterisation of macromolecular structures and interactions. Its main advantage over other solution state approaches is the ability to use D 2 O/H 2 O solvent contrast variation to selectively match out specific parts of a multi-component system. While proteins, nucleic acids, and lipids are readily distinguished in this way, it is not possible to locate different parts of a protein-protein system without the introduction of additional contrast by selective deuteration. Here, we describe new methods by which 'matchout labelled' proteins can be produced using Escherichia coli and Pichia pastoris expression systems in high cell-density cultures. The method is designed to produce protein that has a scattering length density that is very close to that of 100% D 2 O, providing clear contrast when used with hydrogenated partner proteins in a complex. This allows the production of a single sample system for which SANS measurements at different solvent contrasts can be used to distinguish and model the hydrogenated component, the deuterated component, and the whole complex. The approach, which has significant cost advantages, has been extensively tested for both types of expression system.

  19. 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.

  20. New insight into the structure of RNA in red clover necrotic mosaic virus and the role of divalent cations revealed by small-angle neutron scattering.

    Science.gov (United States)

    Martin, Stanton L; He, Lilin; Meilleur, Flora; Guenther, Richard H; Sit, Tim L; Lommel, Steven A; Heller, William T

    2013-08-01

    Red clover necrotic mosaic virus (RCNMV) is a 36-nm-diameter, T = 3 icosahedral plant virus with a genome that is split between two single-stranded RNA molecules of approximately 3.9 kb and 1.5 kb, as well as a 400-nucleotide degradation product. The structure of the virus capsid and its response to removing Ca(2+) and Mg(2+) was previously studied by cryo-electron microscopy (cryo-EM) (Sherman et al. J Virol 80:10395-10406, 2006) but the structure of the RNA was only partially resolved in that study. To better understand the organization of the RNA and conformational changes resulting from the removal of divalent cations, small-angle neutron scattering with contrast variation experiments were performed. The results expand upon the cryo-EM results by clearly showing that virtually all of the RNA is contained in a thin shell that is in contact with the interior domains of the viral capsid protein, and they provide new insight into changes in the RNA packing that result from removal of divalent cations.

  1. Analysis of the solution structure of Thermosynechococcus elongatus photosystem I in n-dodecyl-β-d-maltoside using small-angle neutron scattering and molecular dynamics simulation

    Energy Technology Data Exchange (ETDEWEB)

    Le, Rosemary K. [Univ. of Tennessee, Knoxville, TN (United States); Harris, Bradley J. [Univ. of Tennessee, Knoxville, TN (United States); Iwuchukwu, Ifeyinwa J. [Univ. of Tennessee, Knoxville, TN (United States); Bruce, Barry D. [Univ. of Tennessee, Knoxville, TN (United States); Cheng, Xiaolin [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Qian, Shuo [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Heller, William T. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); O’Neill, Hugh [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Frymier, Paul D. [Univ. of Tennessee, Knoxville, TN (United States)

    2014-05-01

    Small-angle neutron scattering (SANS) and molecular dynamics (MD) simulation were used to investigate the structure of trimeric photosystem I (PSI) from Thermosynechococcus elongatus (T. elongatus) stabilized in n-dodecyl-β-d-maltoside (DDM) detergent solution. Scattering curves of detergent and protein–detergent complexes were measured at 18% D2O, the contrast match point for the detergent, and 100% D2O, allowing observation of the structures of protein/detergent complexes. It was determined that the maximum dimension of the PSI–DDM complex was consistent with the presence of a monolayer belt of detergent around the periphery of PSI. A dummy-atom reconstruction of the shape of the complex from the SANS data indicates that the detergent envelope has an irregular shape around the hydrophobic periphery of the PSI trimer rather than a uniform, toroidal belt around the complex. A 50 ns MD simulation model (a DDM ring surrounding the PSI complex with extra interstitial DDM) of the PSI–DDM complex was developed for comparison with the SANS data. The results suggest that DDM undergoes additional structuring around the membrane-spanning surface of the complex instead of a simple, relatively uniform belt, as is generally assumed for studies that use detergents to solubilize membrane proteins.

  2. Small angle X-ray scattering data and structure factor fitting for the study of the quaternary structure of the spermidine N-acetyltransferase SpeG

    Directory of Open Access Journals (Sweden)

    Steven Weigand

    2016-03-01

    Full Text Available Here we describe the treatment of the small-angle X-ray Scattering (SAXS data used during SpeG quaternary structure study as part of the research article “Substrate induced allosteric change in the quaternary structure of the spermidine N-acetyltransferase SpeG” published in Journal of Molecular Biology [1]. These data were collected on two separate area detectors as separate dilution series of the SpeG and the SpeG with spermine samples along with data from their companion buffers. The data were radially integrated, corrected for incident beam variation, and scaled to absolute units. After subtraction of volume-fraction scaled buffer scattering and division by the SpeG concentration, multiple scattering curves free of an inter-molecular structure factor were derived from the dilution series. Rather than extrapolating to infinite dilution, the structure factor contribution was estimated by fitting to the full set of data provided by dividing the scattering curves of a dilution series by the curve from the most dilute sample in that series.

  3. Low-Resolution Structure of the Full-Length Barley (Hordeum vulgare) SGT1 Protein in Solution, Obtained Using Small-Angle X-Ray Scattering

    Science.gov (United States)

    Taube, Michał; Pieńkowska, Joanna R.; Jarmołowski, Artur; Kozak, Maciej

    2014-01-01

    SGT1 is an evolutionarily conserved eukaryotic protein involved in many important cellular processes. In plants, SGT1 is involved in resistance to disease. In a low ionic strength environment, the SGT1 protein tends to form dimers. The protein consists of three structurally independent domains (the tetratricopeptide repeats domain (TPR), the CHORD- and SGT1-containing domain (CS), and the SGT1-specific domain (SGS)), and two less conserved variable regions (VR1 and VR2). In the present study, we provide the low-resolution structure of the barley (Hordeum vulgare) SGT1 protein in solution and its dimer/monomer equilibrium using small-angle scattering of synchrotron radiation, ab-initio modeling and circular dichroism spectroscopy. The multivariate curve resolution least-square method (MCR-ALS) was applied to separate the scattering data of the monomeric and dimeric species from a complex mixture. The models of the barley SGT1 dimer and monomer were formulated using rigid body modeling with ab-initio structure prediction. Both oligomeric forms of barley SGT1 have elongated shapes with unfolded inter-domain regions. Circular dichroism spectroscopy confirmed that the barley SGT1 protein had a modular architecture, with an α-helical TPR domain, a β-sheet sandwich CS domain, and a disordered SGS domain separated by VR1 and VR2 regions. Using molecular docking and ab-initio protein structure prediction, a model of dimerization of the TPR domains was proposed. PMID:24714665

  4. Insights into Surface Interactions between Metal Organic Frameworks and Gases during Transient Adsorption and Diffusion by In-Situ Small Angle X-ray Scattering

    Directory of Open Access Journals (Sweden)

    Ludovic F. Dumée

    2016-09-01

    Full Text Available The fabrication of molecular gas sieving materials with specific affinities for a single gas species and able to store large quantities of materials at a low or atmospheric pressure is desperately required to reduce the adverse effects of coal and oil usage in carbon capture. Fundamental understanding of the dynamic adsorption of gas, the diffusion mechanisms across thin film membranes, and the impact of interfaces play a vital role in developing these materials. In this work, single gas permeation tests across micro-porous membrane materials, based on metal organic framework crystals grown on the surface of carbon nanotubes (ZiF-8@CNT, were performed for the first time in-situ at the Australian Synchrotron on the small angle X-ray scattering beamline in order to reveal molecular sieving mechanisms and gas adsorption within the material. The results show that specific chemi-sorption of CO2 across the ZiF-8 crystal lattices affected the morphology and unit cell parameters, while the sieving of other noble or noble like gases across the ZiF-8@CNT membranes was found to largely follow Knudsen diffusion. This work demonstrates for the first time a novel and effective technique to assess molecular diffusion at the nano-scale across sub-nano-porous materials by probing molecular flexibility across crystal lattice and single cell units.

  5. PAMAM6 dendrimers and DNA: pH dependent "beads-on-a-string" behavior revealed by small angle X-ray scattering

    CERN Document Server

    Dootz, Rolf; Pfohl, Thomas

    2011-01-01

    DNA interactions with polycations are not only important for our understanding of chromatin compaction but also for characterizing DNA-binding proteins involved in transcription, replication and repair. DNA is known to form several types of liquid-crystalline phases depending, among other factors, on polycation structure and charge density. Theoretical studies and simulations have predicted the wrapping of DNA around spherical positively charged polycations. As a potential mimic of the histone octamer or other DNA wrapping proteins, poly(amido amine) generation 6 (PAMAM6) dendrimers have been chosen for our study. The self-assembly of DNA induced by PAMAM6 has been investigated using small angle X-ray scattering (SAXS) in order to reveal the assemblies' structure dependence on the pH of the environment and on dendrimers concentration. We demonstrate that at pH 8.5 dense phases are formed and characterized by a 2D-columnar hexagonal lattice which is transformed into a 3D hexagonal lattice with increasing dendr...

  6. Effect of urea on heat-induced gelation of bovine serum albumin (BSA) studied by rheology and small angle neutron scattering (SANS)

    Science.gov (United States)

    Nnyigide, Osita Sunday; Oh, Yuna; Song, Hyeong Yong; Park, Eun-kyoung; Choi, Soo-Hyung; Hyun, Kyu

    2017-05-01

    This paper reports the effects of urea on the heat-induced gelation of bovine serum albumin (BSA), which was studied by the tube inversion method, rheological measurements, and small-angle neutron scattering (SANS). An increase in the urea concentration accelerated the rate of gelation because the protein molecules have already been unfolded to some extent during sample preparation in the urea solution. In addition, the BSA solution in the presence of urea underwent a sol-gel-sol transition during the time sweep test at a constant temperature of 80oC. On the other hand, the BSA solution without urea turned into a hard and brittle gel that did not return to the solution state during isothermal heating at a constant temperature of 80oC. Aggregation and re-bonding of the denatured and unfolded protein chains led to gel formation. Urea added to the protein denatures its tertiary and secondary structures by simultaneously disrupting the hydrogen bonds, hydrophobic interactions, and altering the solvent properties. Furthermore, urea induces thermoreversible chemical interactions in BSA solutions leading to the formation of a gel with dynamic properties under these experimental conditions.

  7. 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.

  8. The new NCPSS BL19U2 beamline at the SSRF for small-angle X-ray scattering from biological macromolecules in solution1

    Science.gov (United States)

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

    2016-01-01

    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. PMID:27738413

  9. Implementation and performance of SIBYLS: a dual endstation small-angle X-ray scattering and macromolecular crystallography beamline at the Advanced Light Source.

    Science.gov (United States)

    Classen, Scott; Hura, Greg L; Holton, James M; Rambo, Robert P; Rodic, Ivan; McGuire, Patrick J; Dyer, Kevin; Hammel, Michal; Meigs, George; Frankel, Kenneth A; Tainer, John A

    2013-02-01

    The SIBYLS beamline (12.3.1) of the Advanced Light Source at Lawrence Berkeley National Laboratory, supported by the US Department of Energy and the National Institutes of Health, is optimized for both small-angle X-ray scattering (SAXS) and macromolecular crystallography (MX), making it unique among the world's mostly SAXS or MX dedicated beamlines. Since SIBYLS was commissioned, assessments of the limitations and advantages of a combined SAXS and MX beamline have suggested new strategies for integration and optimal data collection methods and have led to additional hardware and software enhancements. Features described include a dual mode monochromator [containing both Si(111) crystals and Mo/B(4)C multilayer elements], rapid beamline optics conversion between SAXS and MX modes, active beam stabilization, sample-loading robotics, and mail-in and remote data collection. These features allow users to gain valuable insights from both dynamic solution scattering and high-resolution atomic diffraction experiments performed at a single synchrotron beamline. Key practical issues considered for data collection and analysis include radiation damage, structural ensembles, alternative conformers and flexibility. SIBYLS develops and applies efficient combined MX and SAXS methods that deliver high-impact results by providing robust cost-effective routes to connect structures to biology and by performing experiments that aid beamline designs for next generation light sources.

  10. 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.

  11. Microstructure of oxide dispersion strengthened Eurofer and iron-chromium alloys investigated by means of small-angle neutron scattering and transmission electron microscopy

    Science.gov (United States)

    Heintze, C.; Bergner, F.; Ulbricht, A.; Hernández-Mayoral, M.; Keiderling, U.; Lindau, R.; Weissgärber, T.

    2011-09-01

    Oxide dispersion strengthening of ferritic/martensitic chromium steels is a promising route for the extension of the range of operation temperatures for nuclear applications. The investigation of dedicated model alloys is an important means in order to separate individual effects contributing to the mechanical behaviour under irradiation and to improve mechanistic understanding. A powder metallurgy route based on spark plasma sintering was applied to fabricate oxide dispersion strengthened (ODS) Fe9Cr model materials. These materials along with Eurofer97 and ODS-Eurofer were investigated by means of small-angle neutron scattering (SANS) and TEM. For Fe9Cr-0.6 wt.%Y 2O 3, TEM results indicate a peak radius of the size distribution of Y 2O 3 particles of 4.2 nm with radii ranging up to 15 nm, and a volume fraction of 0.7%, whereas SANS indicates a peak radius of 3.8 nm and a volume fraction of 0.6%. It was found that the non-ODS Fe9Cr and Eurofer97 are suitable reference materials for ODS-Fe9Cr and ODS-Eurofer, respectively, and that the ODS-Fe9Cr variants are suitable model materials for the separated investigation of irradiation-Y 2O 3 particle interaction effects.

  12. 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.

  13. Small-angle neutron scattering study of protein crowding in liquid and solid phases: lysozyme in aqueous solution, frozen solution, and carbohydrate powders.

    Science.gov (United States)

    Curtis, Joseph E; Nanda, Hirsh; Khodadadi, Sheila; Cicerone, Marcus; Lee, Hyo Jin; McAuley, Arnold; Krueger, Susan

    2012-08-16

    The structure, interactions, and interprotein configurations of the protein lysozyme were studied in a variety of phases. These properties have been studied under a variety of solution conditions before, during, and after freezing and after freeze-drying in the presence of glucose and trehalose. Contrast variation experiments have also been performed to determine which features of the scattering in the frozen solutions are from the protein and which are from the ice structure. Data from lysozyme at concentrations ranging from 1 to 100 mg/mL in solution and water ice with NaCl concentrations ranging from 0 to 0.4 mol/L are fit to model small-angle neutron scattering (SANS) intensity functions consisting of an ellipsoidal form factor and either a screened-Coulomb or hard-sphere structure factor. Parameters such as protein volume fraction and long dimension are followed as a function of temperature and salt concentration. The SANS results are compared to real space models of concentrated lysozyme solutions at the same volume fractions obtained from Monte Carlo simulations. A cartoon representation of the frozen lysozyme solution in 0 mol/L NaCl is presented based on the SANS and Monte Carlo results, along with those obtained from other complementary methods.

  14. 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.

  15. Ultra-small-angle X-ray scattering-X-ray photon correlation spectroscopy studies of incipient structural changes in amorphous calcium phosphate-based dental composites.

    Science.gov (United States)

    Zhang, Fan; Allen, Andrew J; Levine, Lyle E; Espinal, Laura; Antonucci, Joseph M; Skrtic, Drago; O'Donnell, Justin N R; Ilavsky, Jan

    2012-05-01

    The local structural changes in amorphous calcium phosphate (ACP)-based dental composites were studied under isothermal conditions using both static, bulk measurement techniques and a recently developed methodology based on combined ultra-small angle X-ray scattering-X-ray photon correlation spectroscopy (USAXS-XPCS), which permits a dynamic approach. While results from conventional bulk measurements do not show clear signs of structural change, USAXS-XPCS results reveal unambiguous evidence for local structural variations on a similar time scale to that of water loss in the ACP fillers. A thermal-expansion-based simulation indicates that thermal behavior alone does not account for the observed dynamics. Together, these results suggest that changes in the water content of ACP affect the composite morphology due to changes in ACP structure that occur without an amorphous-to-crystalline conversion. It is also noted that biomedical materials research could benefit greatly from USAXS-XPCS, a dynamic approach. Copyright © 2012 Wiley Periodicals, Inc.

  16. Small angle X-ray scattering study of poly(N-isopropyl acrylamide) based cryogels near the volume-phase transition temperature

    Energy Technology Data Exchange (ETDEWEB)

    Chalal, Mohand [Laboratoire d' Electronique Quantique, Faculte de Physique, USTHB Alger, 16111 Alger (Algeria); Ehrburger-Dolle, Francoise; Morfin, Isabelle [Laboratoire de Spectrometrie Physique, UMR 5588 CNRS/UJF, 38402 Saint Martin d' Heres (France); Armas, Maria-Rosa Aguilar de; Lopez, Maria-Luisa [Instituto de Ciencia y TecnologIa de PolImeros, CSIC and CIBER-BBN, 28006 Madrid (Spain); Bley, Francoise, E-mail: francoise.ehrburger-dolle@ujf-grenoble.f [Science et Ingenierie des Materiaux et Procedes, UMR 5266 CNRS/INPG/UJF, 38402 Saint Martin d' Heres (France)

    2010-10-01

    The structural modifications induced by changes in temperature are investigated by Small-Angle X-ray Scattering (SAXS) over a broad range of q-values (3.5x10{sup -2} - 12 nm{sup -1}) in cryogels based on N-isopropylacrylamide (NIPA) and/or 2-Hydroxyethyl methacrylate-L-Lactide-Dextran (HEMA-LLA-D) macromer. Various copolymeric cryogels of these two monomers are prepared by cryopolymerization yielding macroporous gels (cryogels). For the plain pNIPA cryogel, the SAXS curves obtained at each temperature are well fitted by a sum of four equations describing respectively the scattering resulting from the gel surface (power law), from the solid-like (Guinier equation) and liquid-like (Ornstein-Zernike equation) heterogeneities and from the chain-chain correlation yielding a broad peak (pseudo-Voigt equation) in the high-q domain. The temperature dependence of the parameters obtained from the fit is analyzed and discussed. It is shown that the existence of an isoscattering (or isosbestic) point observed in pNIPA gels and in some copolymers is related to features observed by Differential Scanning Calorimetry and swelling ratio measurements.

  17. Report detailing comparative analysis of results from high flux isotope reactor and national institute of standards technology small-angle neutron scattering experiments

    Energy Technology Data Exchange (ETDEWEB)

    Sokolov, Mikhail A. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Littrell, Ken [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Wells, Peter [Univ. of California, Santa Barbara, CA (United States); Cunningham, Nicholas J. [Univ. of California, Santa Barbara, CA (United States)

    2015-09-01

    discussed above, see Ref. [5] and [6] for details. UCSB has performed a large number of SANS experiments in the past at the National Institute of Standards and Technology (NIST) Center for Neutron Research (NCNR). These data are taken from RPV steels irradiated in a wide range of flux-fluence space and will be very useful in comparing to the upcoming UCSB ATR-2 irradiation characterization since most of the SANS experiments with ATR-2 materials will be performed at ORNL High Flux Isotope Reactor (HFIR). However in the previous report [7], some discrepancies were observed between HFIR and NCNR generated data. One of the hypotheses was that there was some kind of extra scattering occurring off the sample holders that results in the HFIR curves falling above the NCNR curves. To test this hypothesis, UCSB provided thermally aged samples that have been previously run at NCNR to ORNL for testing at HFIR while ORNL performed some improvements to experimental set up at HFIR. This report provides the status for the Level 3 Milestone (M3LW-15OR0402013), Complete report detailing comparative analysis of results from High Flux Isotope Reactor and National Institute of Standards and Technology small-angle neutron scattering experiments. This milestone is associated with small-angle neutron scattering characterization at the High Flux Isotope Reactor of various model alloys that had been previously characterized at NCNR by UCSB.

  18. Small-angle neutron scattering studies of mineralization on BSA coated citrate capped gold nanoparticles used as a model surface for membrane scaling in RO wastewater desalination.

    Science.gov (United States)

    Dahdal, Y N; Pipich, V; Rapaport, H; Oren, Y; Kasher, R; Schwahn, D

    2014-12-23

    Bovine serum albumin (BSA) coated on citrate capped gold nanoparticles (BSA-GNPs) was exposed to a simulated wastewater effluent (SSE) in order to study the mineralization and thereby mimic scaling at biofouled membranes of reverse osmosis (RO) wastewater desalination plants. RO is a leading technology of achieving freshwater quality as it has the capability of removing both dissolved inorganic salts and organic contaminants from tertiary wastewater effluents. The aim was to better understand one of the major problems facing this technology which is fouling of the membranes, mainly biofouling and scaling by calcium phosphate. The experiments were performed using the small-angle neutron scattering (SANS) technique. The nanoparticles, GNPs, stabilized by the citrate groups showed 30 Å large particles having a homogeneous distribution of gold and citrate with a gold volume fraction of the order of 1%. On the average two BSA monomers are grafted at 2.4 GNPs. The exposed BSA-GNPs to SSE solution led to immediate mineralization of stable composite particles of the order of 0.2 μm diameter and a mineral volume fraction between 50% and 80%. The volume fraction of the mineral was of the order of 10(-5), which is roughly 3 times larger but an order of magnitude smaller than the maximum possible contents of respectively calcium phosphate and calcium carbonate in the SSE solution. Considering the extreme low solubility product of calcium phosphate, we suggest total calcium phosphate and partially (5-10%) calcium carbonate formation in the presence of BSA-GNPs.

  19. Structure and optical function of amorphous photonic nanostructures from avian feather barbs: a comparative small angle X-ray scattering (SAXS) analysis of 230 bird species.

    Science.gov (United States)

    Saranathan, Vinodkumar; Forster, Jason D; Noh, Heeso; Liew, Seng-Fatt; Mochrie, Simon G J; Cao, Hui; Dufresne, Eric R; Prum, Richard O

    2012-10-07

    Non-iridescent structural colours of feathers are a diverse and an important part of the phenotype of many birds. These colours are generally produced by three-dimensional, amorphous (or quasi-ordered) spongy β-keratin and air nanostructures found in the medullary cells of feather barbs. Two main classes of three-dimensional barb nanostructures are known, characterized by a tortuous network of air channels or a close packing of spheroidal air cavities. Using synchrotron small angle X-ray scattering (SAXS) and optical spectrophotometry, we characterized the nanostructure and optical function of 297 distinctly coloured feathers from 230 species belonging to 163 genera in 51 avian families. The SAXS data provided quantitative diagnoses of the channel- and sphere-type nanostructures, and confirmed the presence of a predominant, isotropic length scale of variation in refractive index that produces strong reinforcement of a narrow band of scattered wavelengths. The SAXS structural data identified a new class of rudimentary or weakly nanostructured feathers responsible for slate-grey, and blue-grey structural colours. SAXS structural data provided good predictions of the single-scattering peak of the optical reflectance of the feathers. The SAXS structural measurements of channel- and sphere-type nanostructures are also similar to experimental scattering data from synthetic soft matter systems that self-assemble by phase separation. These results further support the hypothesis that colour-producing protein and air nanostructures in feather barbs are probably self-assembled by arrested phase separation of polymerizing β-keratin from the cytoplasm of medullary cells. Such avian amorphous photonic nanostructures with isotropic optical properties may provide biomimetic inspiration for photonic technology.

  20. Investigation of the effect of sugar stereochemistry on biologically relevant lyotropic phases from branched-chain synthetic glycolipids by small-angle X-ray scattering.

    Science.gov (United States)

    Zahid, N Idayu; Conn, Charlotte E; Brooks, Nicholas J; Ahmad, Noraini; Seddon, John M; Hashim, Rauzah

    2013-12-23

    Synthetic branched-chain glycolipids are suitable as model systems in understanding biological cell membranes, particularly because certain natural lipids possess chain branching. Herein, four branched-chain glycopyranosides, namely, 2-hexyl-decyl-α-D-glucopyranoside (α-Glc-OC10C6), 2-hexyl-decyl-β-D-glucopyranoside (β-Glc-OC10C6), 2-hexyl-decyl-α-D-galactopyranoside (α-Gal-OC10C6), and 2-hexyl-decyl-β-D-galactopyranoside (β-Gal-OC10C6), with a total alkyl chain length of 16 carbon atoms have been synthesized, and their phase behavior has been studied. The partial binary phase diagrams of these nonionic surfactants in water were investigated by optical polarizing microscopy (OPM) and small-angle X-ray scattering (SAXS). The introduction of chain branching in the hydrocarbon chain region is shown to result in the formation of inverse structures such as inverse hexagonal and inverse bicontinuous cubic phases. A comparison of the four compounds showed that they exhibited different polymorphism, especially in the thermotropic state, as a result of contributions from anomeric and epimeric effects according to their stereochemistry. The neat α-Glc-OC10C6 compound exhibited a lamellar (Lα) phase whereas dry α-Gal-OC10C6 formed an inverse bicontinuous cubic Ia3d (QII(G)) phase. Both β-anomers of glucoside and galactoside adopted the inverse hexagonal phase (HII) in the dry state. Generally, in the presence of water, all four glycolipids formed inverse bicontinuous cubic Ia3d (QII(G)) and Pn3m (QII(D)) phases over wide temperature and concentration ranges. The formation of inverse nonlamellar phases by these Guerbet branched-chain glycosides confirms their potential as materials for novel biotechnological applications such as drug delivery and crystallization of membrane proteins.

  1. 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.

  2. Characterization of polymer-silica nanocomposite particles with core-shell morphologies using Monte Carlo simulations and small angle X-ray scattering.

    Science.gov (United States)

    Balmer, Jennifer A; Mykhaylyk, Oleksandr O; Schmid, Andreas; Armes, Steven P; Fairclough, J Patrick A; Ryan, Anthony J

    2011-07-05

    A two-population model based on standard small-angle X-ray scattering (SAXS) equations is verified for the analysis of core-shell structures comprising spherical colloidal particles with particulate shells. First, Monte Carlo simulations of core-shell structures are performed to demonstrate the applicability of the model. Three possible shell packings are considered: ordered silica shells due to either charge-dependent repulsive or size-dependent Lennard-Jones interactions or randomly arranged silica particles. In most cases, the two-population model produces an excellent fit to calculated SAXS patterns for the simulated core-shell structures, together with a good correlation between the fitting parameters and structural parameters used for the simulation. The limits of application are discussed, and then, this two-population model is applied to the analysis of well-defined core-shell vinyl polymer/silica nanocomposite particles, where the shell comprises a monolayer of spherical silica nanoparticles. Comprehensive SAXS analysis of a series of poly(styrene-co-n-butyl acrylate)/silica colloidal nanocomposite particles (prepared by the in situ emulsion copolymerization of styrene and n-butyl acrylate in the presence of a glycerol-functionalized silica sol) allows the overall core-shell particle diameter, the copolymer latex core diameter and polydispersity, the mean silica shell thickness, the mean silica diameter and polydispersity, the volume fractions of the two components, the silica packing density, and the silica shell structure to be obtained. These experimental SAXS results are consistent with electron microscopy, dynamic light scattering, thermogravimetry, helium pycnometry, and BET surface area studies. The high electron density contrast between the (co)polymer and the silica components, together with the relatively low polydispersity of these core-shell nanocomposite particles, makes SAXS ideally suited for the characterization of this system. Moreover

  3. Growth kinetics of lipid-based nanodiscs to unilamellar vesicles-a time-resolved small angle neutron scattering (SANS) study.

    Science.gov (United States)

    Mahabir, Suanne; Small, Darcy; Li, Ming; Wan, Wankei; Kučerka, Norbert; Littrell, Kenneth; Katsaras, John; Nieh, Mu-Ping

    2013-03-01

    Mixtures of dimyristoyl-phosphatidylcholine (DMPC), dimyristoyl-phosphatidylglycerol (DMPG) and dihexanoyl-phosphatidylcholine (DHPC) in aqueous solutions spontaneously form monodisperse, bilayered nanodiscs (also known as "bicelles") at or below the melting transition temperature of DMPC (T(M) ~23°C). In dilute systems above the main transition temperature T(M) of DMPC, bicelles coalesce (increasing their diameter) and eventually self-fold into unilamellar vesicles (ULVs). Time-resolved small angle neutron scattering was used to study the growth kinetics of nanodiscs below and equal to T(M) over a period of hours as a function of temperature at two lipid concentrations in presence or absence of NaCl salt. Bicelles seem to undergo a sudden initial growth phase with increased temperature, which is then followed by a slower reaction-limited growth phase that depends on ionic strength, lipid concentration and temperature. The bicelle interaction energy was derived from the colloidal theory of Derjaguin and Landau, and Verwey and Overbeek (DLVO). While the calculated total energy between discs is attractive and proportional to their growth rate, a more detailed mechanism is proposed to describe the mechanism of disc coalescence. After annealing at low temperature (low-T), samples were heated to 50°C in order to promote the formation of ULVs. Although the low-T annealing of samples has only a marginal effect on the mean size of end-state ULVs, it does affect their polydispersity, which increases with increased T, presumably driven by the entropy of the system. Published by Elsevier B.V.

  4. Model-based approaches for the determination of lipid bilayer structure from small-angle neutron and X-ray scattering data.

    Science.gov (United States)

    Heberle, Frederick A; Pan, Jianjun; Standaert, Robert F; Drazba, Paul; Kučerka, Norbert; Katsaras, John

    2012-10-01

    Some of our recent work has resulted in the detailed structures of fully hydrated, fluid phase phosphatidylcholine (PC) and phosphatidylglycerol (PG) bilayers. These structures were obtained from the joint refinement of small-angle neutron and X-ray data using the scattering density profile (SDP) models developed by Kučerka et al. (Biophys J 95:2356-2367, 2008; J Phys Chem B 116:232-239, 2012). In this review, we first discuss models for the standalone analysis of neutron or X-ray scattering data from bilayers, and assess the strengths and weaknesses inherent to these models. In particular, it is recognized that standalone data do not contain enough information to fully resolve the structure of naturally disordered fluid bilayers, and therefore may not provide a robust determination of bilayer structure parameters, including the much-sought-after area per lipid. We then discuss the development of matter density-based models (including the SDP model) that allow for the joint refinement of different contrast neutron and X-ray data, as well as the implementation of local volume conservation within the unit cell (i.e., ideal packing). Such models provide natural definitions of bilayer thicknesses (most importantly the hydrophobic and Luzzati thicknesses) in terms of Gibbs dividing surfaces, and thus allow for the robust determination of lipid areas through equivalent slab relationships between bilayer thickness and lipid volume. In the final section of this review, we discuss some of the significant findings/features pertaining to structures of PC and PG bilayers as determined from SDP model analyses.

  5. Model-based Approaches for the Determination of Lipid Bilayer Structure from Small-Angle Neutron and X-ray Scattering Data

    Energy Technology Data Exchange (ETDEWEB)

    Heberle, Frederick A [ORNL; Pan, Jianjun [ORNL; Standaert, Robert F [ORNL; Drazba, Paul [ORNL; Kucerka, Norbert [Canadian Neutron Beam Centre and Comelius University (Slovakia); Katsaras, John [ORNL

    2012-01-01

    Some of our recent work has resulted in the detailed structures of fully hydrated, fluid phase phosphatidylcholine (PC) and phosphatidylglycerol (PG) bilayers. These structures were obtained from the joint refinement of small-angle neutron and X-ray data using the scattering density profile (SDP) models developed by Ku erka et al. (Ku erka et al. 2012; Ku erka et al. 2008). In this review, we first discuss models for the standalone analysis of neutron or X-ray scattering data from bilayers, and assess the strengths and weaknesses inherent in these models. In particular, it is recognized that standalone data do not contain enough information to fully resolve the structure of inherently disordered fluid bilayers, and therefore may not provide a robust determination of bilayer structural parameters, including the much sought after area per lipid. We then discuss the development of matter density-based models (including the SDP model) that allow for the joint refinement of different contrast neutron and X-ray data sets, as well as the implementation of local volume conservation in the unit cell (i.e., ideal packing). Such models provide natural definitions of bilayer thicknesses (most importantly the hydrophobic and Luzzati thicknesses) in terms of Gibbs dividing surfaces, and thus allow for the robust determination of lipid areas through equivalent slab relationships between bilayer thickness and lipid volume. In the final section of this review, we discuss some of the significant findings/features pertaining to structures of PC and PG bilayers as determined from SDP model analyses.

  6. 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.

  7. 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.

  8. Deuterium Labeling Together with Contrast Variation Small-Angle Neutron Scattering Suggests How Skp Captures and Releases Unfolded Outer Membrane Proteins.

    Science.gov (United States)

    Zaccai, Nathan R; Sandlin, Clifford W; Hoopes, James T; Curtis, Joseph E; Fleming, Patrick J; Fleming, Karen G; Krueger, Susan

    2016-01-01

    In Gram-negative bacteria, the chaperone protein Skp forms specific and stable complexes with membrane proteins while they are transported across the periplasm to the outer membrane. The jellyfish-like architecture of Skp is similar to the eukaryotic and archaeal prefoldins and the mitochondrial Tim chaperones, that is the α-helical "tentacles" extend from a β-strand "body" to create an internal cavity. Contrast variation small-angle neutron scattering (SANS) experiments on Skp alone in solution and bound in two different complexes to unfolded outer membrane proteins (uOMPs), OmpA and OmpW, demonstrate that the helical tentacles of Skp bind their substrate in a clamp-like mechanism in a conformation similar to that previously observed in the apo crystal structure of Skp. Deuteration of the uOMP component combined with contrast variation analysis allowed the shapes of Skp and uOMP as well as the location of uOMP with respect to Skp to be determined in both complexes. This represents unique information that could not be obtained without deuterium labeling of the uOMPs. The data yield the first direct structural evidence that the α-helical Skp tentacles move closer together on binding its substrate and that the structure of Skp is different when binding different uOMPs. This work presents, by example, a tutorial on performing SANS experiments using both deuterium labeling and contrast variation, including SANS theory, sample preparation, data collection, sample quality validation, data analysis, and structure modeling. © 2016 Elsevier Inc. All rights reserved.

  9. 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%....

  10. Reaction of bone nanostructure to a biodegrading Magnesium WZ21 implant - A scanning small-angle X-ray scattering time study.

    Science.gov (United States)

    Grünewald, T A; Ogier, A; Akbarzadeh, J; Meischel, M; Peterlik, H; Stanzl-Tschegg, S; Löffler, J F; Weinberg, A M; Lichtenegger, H C

    2016-02-01

    Understanding the implant-bone interaction is of prime interest for the development of novel biodegrading implants. Magnesium is a very promising material in the class of biodegrading metallic implants, owing to its mechanical properties and excellent immunologic response during healing. However, the influence of degrading Mg implants on the bone nanostructure is still an open question of crucial importance for the design of novel Mg implant alloys. This study investigates the changes in the nanostructure of bone following the application of a degrading WZ21 Mg implant (2wt% Y, 1wt% Zn, 0.25wt% Ca and 0.15wt% Mn) in a murine model system over the course of 15months by small angle X-ray scattering. Our investigations showed a direct response of the bone nanostructure after as little as 1month with a realignment of nano-sized bone mineral platelets along the bone-implant interface. The growth of new bone tissue after implant resorption is characterized by zones of lower mineral platelet thickness and slightly decreased order in the stacking of the platelets. The preferential orientation of the mineral platelets strongly deviates from the normal orientation along the shaft and still roughly follows the implant direction after 15months. We explain our findings by considering geometrical, mechanical and chemical factors during the process of implant resorption. The advancement of surgical techniques and the increased life expectancy have caused a growing demand for improved bone implants. Ideally, they should be bio-resorbable, support bone as long as necessary and then be replaced by healthy bone tissue. Magnesium is a promising candidate for this purpose. Various studies have demonstrated its excellent mechanical performance, degradation behaviour and immunologic properties. The structural response of bone, however, is not well known. On the nanometer scale, the arrangement of collagen fibers and calcium mineral platelets is an important indicator of structural

  11. Design of the Small Angle Neutron Scattering instrument at the Indiana University Low Energy Neutron Source: Applications to the study of nanostructured materials

    Science.gov (United States)

    Remmes, Nicholas B.

    The Low Energy Neutron Source (LENS) located at the Indiana University Cyclotron Facility (IUCF) is a prototypical long-pulse accelerator-based neutron source. The Small Angle Neutron Scattering (SANS) instrument is one of several planned instruments at the LENS facility. The SANS instrument is a time-of-flight instrument which utilizes a pinhole collimation system and neutron wavelengths up to 20A giving it a q range from about 0.006A-1 to 0.5A-1 with a maximum divergence at the sample of about +/-8mrad. The neutron flux on the sample at the anticipated 8kW mode of operation is anticipated to be greater than 2 x 104n/s.cm 2. The design, calibration, and testing of the LENS SANS instrument is discussed, including Monte-Carlo simulations and analytical calculations used to optimize the collimation design, the placement and design of the pulse-overlap chopper system, and other aspects of the instrument's geometry. The expected resolution, count rates, and other general performance parameters of the instrument are presented and, where possible, compared with experimental results. SANS measurements of a family of tripodal organo-silicon dendrimer molecules using the IPNS SAND and the NCNR NG3 SANS instruments are presented. Variations in the scattering curves are compared for solutions of the dendrimers at multiple concentrations in d-heptane, d-DCM, and d-toluene. Models of both the particle form factor and the structure factor are presented. The measurements suggest a distinct difference between the size and behavior of the highest generation dendrimer in two of the solvents (d-DCM and d-toluene) as compared to a third (d-heptane). Additionally, the dendrimer molecules appear to be forming short chains in solution. A brief study of iron oxide magnetic nanoparticles is also presented. This study includes a presentation of the magnetic measurements of the nanoparticles using a SQUID magnetometer. The measurements indicate contributions by a larger dispersion of

  12. Possible magnetism in vortex cores of superconducting TmNi{sub 2}B{sub 2}C studied by small angle neutron scattering

    Energy Technology Data Exchange (ETDEWEB)

    Abrahamsen, Asger Bech

    2003-11-01

    The compound TmNi{sub 2}B{sub 2}C has previously been studied by Small Angle Neutron Scattering(SANS) with the applied field along the crystalline c-axis and a very rich phase diagram in terms of flux line lattices(FLL) with different symmetries have been observed. One of the FLL transitions is coincident with a magnetic phase transition between two spin density waves. In this thesis additional SANS studies of the FLL phases in TmNi{sub 2}B{sub 2}C are reported and an interpretation of the phase diagram in the paramagnetic region is presented. It is suggested that the square FLL observed is stable in between two transition lines determined by two different length scales. The lower transition field is reached when the distance between the flux lines becomes comparable to the non-locality radius resulting from non-local electrodynamics, whereas the upper transition field is determined from the crossover from intermediate to high flux line density where the vortex cores start to overlap and the superconducting order parameter is suppressed in between the flux lines. A detailed examination of the intensity of the neutron diffraction spots caused by scattering on the flux line lattice in TmNi{sub 2}B{sub 2}C is presented and analyzed on the basis of the form factor of an isolated flux line. This analysis can not provide a good explanation for the observed scattering and it is suggested that the scattering from the Tm ions must be considered. One can argue that the moments of the Tm ions are modulated by the flux line lattice, because the Ruderman-Kittel- Kasuya-Yosida(RKKY) interaction between the Tm ions might be different inside the vortex cores than outside in the superconducting phase. A calculation of the neutron scattering cross section of such a magnetic flux line lattice has been performed and compared to the SANS data. This offers a qualitative explanation of some of the observations, but future work is needed to perform a more quantitative comparison. (au)

  13. 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

  14. Analysis of nano-sized irradiation-induced defects in Fe-base materials by means of small angle neutron scattering and molecular dynamics simulations

    Energy Technology Data Exchange (ETDEWEB)

    Yu, G.

    2008-12-15

    Thermonuclear fusion of light atoms is considered since decades as an unlimited, safe and reliable source of energy that could eventually replace classical sources based on fossil fuel or nuclear fuel. Fusion reactor technology and materials studies are important parts of the fusion energy development program. For the time being, the most promising materials for structural applications in the future fusion power reactors are the Reduced Activation Ferritic/Martensitic (RAFM) steels for which the greatest technology maturity has been achieved, i.e., qualified fabrication routes, welding technology and a general industrial experience are almost available. The most important issues concerning the future use of RAFM steels in fusion power reactors are derived from their irradiation by 14 MeV neutrons that are the product, together with 3.5 MeV helium ions, of the envisaged fusion reactions between deuterium and tritium nuclei. Indeed, exposure of metallic materials to intense fluxes of 14 MeV neutrons will result in the formation of severe displacement damage (about 20-30 dpa per year) and high amounts of helium, which are at the origin of significant changes in the physical and mechanical properties of materials, such as hardening and embrittlement effects. This PhD Thesis work was aimed at investigating how far the Small Angle Neutron Scattering (SANS) technique could be used for detecting and characterizing nano-sized irradiation-induced defects in RAFM steels. Indeed, the resolution limit of Transmission Electron Microscopy (TEM) is about 1 nm in weak beam TEM imaging, and it is usually thought that a large number of irradiation-induced effects have a size below 1 nm in RAFM steels and that these very small defects actually contribute to the irradiation-induced hardening and embrittlement of RAFM steels occurring at irradiation temperatures below about 400 °C. The aim of this work was achieved by combining SANS experiments on unirradiated and irradiated specimens

  15. 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

    Lys(B29)(N(e)¿-carboxyheptadecanoyl) des(B30) human insulin is an insulin analogue belonging to a class of analogues designed to form soluble depots in subcutis by self-association, aiming at a protracted action. On the basis of small angle X-ray scattering (SAXS) supplemented by a range of bioph......Lys(B29)(N(e)¿-carboxyheptadecanoyl) des(B30) human insulin is an insulin analogue belonging to a class of analogues designed to form soluble depots in subcutis by self-association, aiming at a protracted action. On the basis of small angle X-ray scattering (SAXS) supplemented by a range...

  16. Angle performance on optima MDxt

    Energy Technology Data Exchange (ETDEWEB)

    David, Jonathan; Kamenitsa, Dennis [Axcelis Technologies, Inc., 108 Cherry Hill Dr, Beverly, MA 01915 (United States)

    2012-11-06

    Angle control on medium current implanters is important due to the high angle-sensitivity of typical medium current implants, such as halo implants. On the Optima MDxt, beam-to-wafer angles are controlled in both the horizontal and vertical directions. In the horizontal direction, the beam angle is measured through six narrow slits, and any angle adjustment is made by electrostatically steering the beam, while cross-wafer beam parallelism is adjusted by changing the focus of the electrostatic parallelizing lens (P-lens). In the vertical direction, the beam angle is measured through a high aspect ratio mask, and any angle adjustment is made by slightly tilting the wafer platen prior to implant. A variety of tests were run to measure the accuracy and repeatability of Optima MDxt's angle control. SIMS profiles of a high energy, channeling sensitive condition show both the cross-wafer angle uniformity, along with the small-angle resolution of the system. Angle repeatability was quantified by running a channeling sensitive implant as a regular monitor over a seven month period and measuring the sheet resistance-to-angle sensitivity. Even though crystal cut error was not controlled for in this case, when attributing all Rs variation to angle changes, the overall angle repeatability was measured as 0.16 Degree-Sign (1{sigma}). A separate angle repeatability test involved running a series of V-curves tests over a four month period using low crystal cut wafers selected from the same boule. The results of this test showed the angle repeatability to be <0.1 Degree-Sign (1{sigma}).

  17. 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

  18. A single gene for juvenile and middle-age onset open-angle glaucomas confined within a small interval on chromosome 1q

    Energy Technology Data Exchange (ETDEWEB)

    Raymond, V.; Dumont, M.; Plante, M. [CHUL Research Centre, Quebec (Canada)] [and others

    1994-09-01

    Primary open-angle glaucoma (POAG) encompasses a complex of ocular disease entities characterized by an optic neuropathy causing progressive loss of the visual fields and usually associated with elevated intraocular pressure. POAG can be subdivided into two groups according to age of onset: (1) the more prevalent middle to late-age onset chronic open-angle glaucoma (COAG) diagnosed after age 40 and (2) the less common form, juvenile open-angle glaucoma (JOAG), which occurs between 3 years of age and early adulthood. Susceptibility to either COAG or JOAG has been found to be inherited. We studied 141 members of a huge multigeneration French Canadian family affected with an autosomal dominant form of POAG. Both JOAG and COAG were diagnosed in 43 patients. To first position the disease gene, AFM microsatellites markers specific to chromosome 1q21-q31 were selected since linkage of JOAG to this region was recently demonstrated in two Caucasian families. Tight linkage was observed between the JOAG/COAG phenotype and 7 microsatellite markers on chromosome 1q23-q25; a maximum lod score of 6.62 at {theta}=0 was obtained with AFM278ye5. Using a recombination mapping strategy based on a unique founder effect, a characteristic JOAG/COAG haplotype spanning 12 cM was next recognized between loci D1S196 and D1S212. Two key recombination events in affected patients further confined the disease locus within a 5 cM interval between loci D1S445 and D1S452/D1S210. These results are the first to demonstrate that JOAG and one adult form of POAG map at a single locus on chromosome 1q23-q25. They also provide members of this family with a new diagnostic tool to identify the at-risk individuals.

  19. In-Situ Coherent Grazing Incidence Small Angle X-ray Scattering (Co-GISAXS) Studies of Surface Fluctuations of Sputter Deposited WSi2 using X-ray Photon Correlation Spectroscopy (XPCS)

    Science.gov (United States)

    Dahal, Som; Ulbrandt, Jeffrey; Headrick, Randall; Demasi, Alexander; Ludwig, Karl

    2014-03-01

    We performed Coherent Grazing Incidence Small Angle X-ray Scattering (Co-GISAXS) studies of surface dynamics during magnetron sputtering deposited WSi2 amorphous thin films. The local dynamics of surface fluctuations was studied by X-ray Photon Correlation Spectroscopy (XPCS) in the late time regime where the static GIXAXS stops evolving. Our studies reveal that the correlation time of the sputtered species varies as a power law with the in-plane momentum transfer. The experimentally obtained results are compared with predictions from continuum models of surface growth.

  20. Small angle scattering of 59.54 keV photons by elemental samples in the atomic number region 13 ≤ Z ≤ 82

    Directory of Open Access Journals (Sweden)

    L. Vinaykumar

    2016-01-01

    Full Text Available In the present paper, we report the angle integrated coherent scattering cross sections of some elements at low momentum transfer over four angular ranges for some elements in the atomic number range 13≤Z≤82 for 241Am (59.54 keV gamma rays. The coherent scattering cross sections were derived from the experimentally measured total (Coherent + incoherent scattering cross sections for the elements at the energy of interest by subtracting separately the small contribution of the corresponding angle integrated incoherent scattering cross sections. The theoretical angle integrated incoherent scattering cross sections were computed by numerically integrating the values provided in the compilations based on the non-relativistic Hartree-Fock (NRHF model and the modified form factor (MFF model for the charge distribution within the atom. The present values of the angle integrated coherent scattering cross sections of the elements Al, Fe, Cu, Zn, Cd, Sn and Pb at 59.54 keV in the angular ranges of (0∘−4∘, (0∘−6∘, (0∘−8∘ and (0°–10° so obtained are compared with the corresponding theoretical S-matrix data within the range of experimental errors. The root mean square error on the measured cross sections was found to be the lowest for Al at 4.1% and the highest for Pb at 4.9%. For the other elements the error was in between these two values. Possible conclusions are drawn based on the present study.

  1. Filler Network Model of Filled Rubber Materials to Estimate System Size Dependence of Two-Dimensional Small-Angle Scattering Patterns

    Science.gov (United States)

    Hagita, Katsumi; Tominaga, Tetsuo; Hatazoe, Takumi; Sone, Takuo; Takano, Hiroshi

    2018-01-01

    We proposed a filler network toy (FN-toy) model in order to approximately forecast changes in two-dimensional scattering patterns (2DSPs) of nanoparticles (NPs) in crosslinked polymer networks in ultrasmall-angle X-ray scattering (USAXS) experiments under uniaxial elongation. It enables us to estimate the system size dependence of the 2DSP of the NPs. In the FN-toy model, we considered NPs connected by harmonic springs with excluded-volume interactions among the NPs. In this study, we used the NP configurations estimated by reverse Monte Carlo (RMC) analysis for USAXS data observed in SPring-8 experiments on filler-filled styrene butadiene rubber (SBR). In the FN-toy model, we set a bond between every pair of NPs whose distance is less than Cd, where d is the diameter of an NP and C is a parameter that characterizes network properties. We determined the optimal value of C by comparison with 2DSPs of the NPs at 200% elongation for end-modified and unmodified SBR. These 2DSPs are obtained from the results of a large-scale coarse-grained molecular dynamics (CGMD) simulation with 8,192 NPs and 160 million Lennard-Jones (LJ) particles in previous works. For the end-modified SBR, the fitted value is C = 1.367 and for the unmodified SBR, C = 1.258. The difference in C can be regarded as originating from the difference in polymer-NP interactions. We found that the harmonic potential used in the current FN-toy model is not sufficient to reproduce stress-strain curves and local structures of NPs obtained in the previous CGMD simulations, although the FN-toy model can reproduce the 2DSPs. Using the FN-toy model with the fitted value of C, we calculated the 2DSPs of 65,536 and 524,288 NPs, whose initial positions were estimated by RMC analysis for the same USAXS data. It was found that CGMD simulations with 10 billion LJ particles and 524,288 NPs can provide a high-resolution 2DSP that is comparable to the 2DSP observed in USAXS experiments.

  2. Evaluation of Pore Networks in Caprocks at Geologic Storage Sites: A Combined Study using High Temperature and Pressure Reaction Experiments, Small Angle Neutron Scattering, and Focused Ion Beam-Scanning Electron Microscopy

    Science.gov (United States)

    Mouzakis, K. M.; Sitchler, A.; Wang, X.; McCray, J. E.; Kaszuba, J. P.; Rother, G.; Dewers, T. A.; Heath, J. E.

    2011-12-01

    Low permeability rock units, often shales or mudstones, that overlie geologic formations under consideration for CO2 sequestration will help contain injected CO2. CO2 that does flow through these rocks will dissolve into the porewaters, creating carbonic acid lowering the pH. This perturbation of the system may result in mineral dissolution or precipitation, which can change the pore structure and impact the flow properties of the caprocks. In order to investigate the impacts that reaction can have on caprock pore structure, we performed a combination of high pressure high temperature reaction experiments, small angle neutron scattering (SANS) experiments and high resolution focused ion beam-scanning electron microscope (FIB-SEM) imaging on samples from the Gothic shale and Marine Tuscaloosa Group. Small angle neutron scattering was performed on unreacted and reacted caprocks at the High Flux Isotope Reactor at Oak Ridge National Laboratory. New precipitates and pores are observed in high-resolution images of the reacted samples. The precipitates have been preliminarily identified as gypsum or anhydrite, and sulfide minerals. Results from small angle neutron scattering, a technique that provides information about pores and pore/mineral interfaces at scales ~ 5 to 300 nm, show an increased porosity and specific surface area after reaction with brine and CO2. However, there appear to be differences in how the pore networks change between the two samples that are related to sample mineralogy and original pore network structure. Changes to pores and formation of new pores may lead to different capillary sealing behavior and permeability. This combination of controlled laboratory experiments, neutron scattering and high-resolution imaging provides detailed information about the geochemical processes that occur at the pore scale as CO2 reacts with rocks underground. Such information is integral to the evaluation of large-scale CO2 sequestration as a feasible technology

  3. Large neutrino mixing angles in unified theories

    Science.gov (United States)

    Babu, K. S.; Barr, S. M.

    1996-02-01

    Typically in unified theories the neutrino mixing angles, like the Cabibbo-Kobayashi-Maskawa (CKM) angles of the quarks, are related to the small mass ratios between fermions of different generations and are therefore quite small. A new approach for explaining the intergenerational mass hierarchies is proposed here which, while giving small CKM angles, naturally leads to neutrino angles of order unity. Such large mixing angles may be required for a resolution of the atmospheric neutrino anomaly and may also be relevant for the solar neutrino puzzle. The mechanism presented here provides a framework in which novel approaches to the fermion mass question can arise. In particular, within this framework a variant of the texture idea allows highly predictive models to be constructed, an illustrative example of which is given. It is shown how the neutrino mixing angles may be completely determined in such schemes.

  4. Design and Development of a New Electrically Small 3D UHF Spherical Antenna with 360° of Opening Angle in the Whole Space for RFID, WSN, and RSN Applications

    Directory of Open Access Journals (Sweden)

    Abdelhamid Bou-El-Harmel

    2016-01-01

    Full Text Available Several antenna designs have been made in order to obtain a novel electrically small 3D UHF spherical antenna (ka = 0.1916, which has a resonance frequency close to 915 MHz, produces a quasi-isotropic radiation with an opening angle equal to 360° in the whole space, and is used for RFID, WSN, and RSN applications. These antennas are based on different shapes and are wrapped on the Styrofoam sphere surface of dielectric constant close to air (ɛr=1.06. A T-match configuration is used to adapt the input impedance of antennas to a value of 50 Ω. The antennas form allows for placing the sensor electronics in its interior, to reconfigure it for numerous values of impedances and to operate it in other ISM bands by adjusting their geometric parameters.

  5. Glaucoma, Open-Angle

    Science.gov (United States)

    ... USAJobs Home > Statistics and Data > Glaucoma, Open-angle Glaucoma, Open-angle Open-angle Glaucoma Defined In open-angle glaucoma, the fluid passes ... 2010 2010 U.S. Age-Specific Prevalence Rates for Glaucoma by Age and Race/Ethnicity The prevalence of ...

  6. Probing polymer nanocomposite morphology by small angle ...

    Indian Academy of Sciences (India)

    diamine monomers on a flat support which is then dipped in a continuous organic phase containing trimesoyl chloride monomers so that polymer film is formed at the surface of the support by interfacial polycondensation ... Puyam S Singh and Vinod K Aswal. Table 1. Silicon content of the silica–polyamide samples. S1. S2.

  7. Probing polymer nanocomposite morphology by small angle ...

    Indian Academy of Sciences (India)

    2015-11-27

    Nov 27, 2015 ... Polyamide nanocomposite films were prepared from nanometer-sized silica particles having particle radius of gyration (g) of about 66 Å and trimesoyl chloride--phenylene diamine-based polyamides having macromolecular units of about 100-140 Å. The nanoscale morphology of the samples was ...

  8. A small-angle neutron scattering investigation

    Indian Academy of Sciences (India)

    . Introduction. Precipitation in alloy system is a subject of continuing scientific and technological interest [1,2]. PH 13-8 Mo steel is a precipitation-hardened steel, which is capable of achieving high strength and hardness with good corrosion ...

  9. LHC Report: Production and small angles

    CERN Multimedia

    Jan Uythoven for the LHC team

    2012-01-01

    The last two weeks have seen steady luminosity production. The total luminosity of ATLAS and CMS exceeded 19 fb-1, while LHCb reached 1.8 fb-1 and ALICE, 6 pb-1.   As reported in previous LHC reports, the continuous running with large beam intensities is resulting in beam-induced heating of certain elements, such as the synchrotron light monitor (BSRT), the ALFA detector and the injection kicker magnets. These first two elements had shown a sudden increase in temperature in the previous weeks - but only for the components that are on the counter-clockwise rotating beam. By making slight changes to the radiofrequency parameters, which affect the bunch length, the power spectrum of the beam was changed. This significantly reduced the observed heating of the BSRT and the ALFA detector. Another improvement was recently made to the measurement process of the number of transverse oscillations of the beam in one turn, known as the “betatron tune”. The frequency of the betatron tune ...

  10. Tibial plateau leveling osteotomy in small breed dogs with high tibial plateau angles using a 4-hole 1.9/2.5 mm locking T-plate.

    Science.gov (United States)

    Witte, Philip G; Scott, Harry W

    2014-07-01

    To report clinical experiences with tibial plateau leveling osteotomy (TPLO) to address cranial cruciate ligament (CCL) disease in small breed dogs with high tibial plateau angles (TPA) using a specific 4-hole locking T-plate. Retrospective case series. Small breed dogs (30°): n = 19 (29 CCL ruptures). TPLO was performed by standard technique using a 1.9/2.5 mm 4-hole locking T-plate. Preoperative, immediate postoperative, and 6-8 weeks postoperative TPA were measured from radiographs. Lameness was scored subjectively preoperatively and 6-8 weeks postoperatively. Mid to long term follow-up was by client telephone questionnaire (mean, 12.1 months after surgery). Mean ± SD preoperative TPA was 37.0 ± 4.9°, immediate postoperative TPA, 6.4 ± 2.8° and 6-8 weeks postoperative TPA, 8.0 ± 4.9°. Postoperative complications occurred in 4 dogs (13.8%) all of which had been operated as single-session bilateral procedures. Three stifles had failure of a single screw and postoperative increase in TPA. Periprosthetic infection necessitated plate removal in 1 dog. Lameness scores by veterinary assessment reduced from mean 3.4/5 preoperatively to 0.4/5 at 6-8 weeks postoperatively. Mid to long-term follow-up revealed no lameness by owner assessment. A 4-hole 1.9/2.5 mm locking T-plate may be used in the stabilization of unilateral TPLO in small breed dogs with high TPA. © Copyright 2014 by The American College of Veterinary Surgeons.

  11. Small angle particle-particle correlation measurements in the reactions 280 MeV sup 4 sup 0 Ar+ sup 2 sup 7 Al and 670 MeV sup 5 sup 5 Mn+ sup 1 sup 2 C

    CERN Document Server

    Milosevich, Z; De Young, P A; Brown, C M; Kaplan, M; Whitfield, J P; Peterson, D; Dykstra, C; Barton, M; Karol, P J; McMahan, M A

    2001-01-01

    Small-angle particle-particle correlations were measured in the two matching reactions 280 MeV sup 4 sup 0 Ar+ sup 2 sup 7 Al and 670 MeV sup 5 sup 5 Mn+ sup 1 sup 2 C. These two reactions were used to produce the composite nucleus, sup 6 sup 7 Ga*, at the same initial excitation energy of 127 MeV, but with different entrance channel angular momentum distributions. A simple trajectory model was used to compute the average emission times between various particle pairs, and comparisons with the data show that there is a significant difference in the deexcitation of the composite nucleus formed from the two reactions. Statistical model calculations were compared to the experimental observations with the added constraint that the model input parameters were consistent with those derived from observed charged-particle energy spectra and angular distributions. It was found that the calculated correlation functions were insensitive to the input spin distributions, but agreed fairly well with the data from the lower-...

  12. Creation of high energy bremsstrahlung and intensity by a multitarget and refocusing of the scattered electrons by small-angle backscatter at the wall of a cone and magnetic fields

    CERN Document Server

    Ulmer, W

    2011-01-01

    The yield of bremsstrahlung from collisions of fast electrons (energy at least 6 MeV) with a tungsten target can be significantly improved by exploitation of Tungsten wall scatter in a multi-layered target. The Tungsten wall can serve to refocuse small angle scattered electrons. It is necessary that the thickness of one Tungsten layer does not exceed 0.02 mm. Further refocusing of electrons results from suitable magnetic fields with field strength between 0.5 Tesla and 6 Tesla (if the cone with multi-layered targets is rather narrow). Linear accelerators in radiation therapy only need refocusing by wall scatter without further magnetic fields (standard case: ca. 100 - 000 plates with 0.01 mm thickness and 1 mm distance between the plates). The construction of a very narrow bremsstrahlung beam with extremely high photon intensity requires an additional strong magnetic field (order 1 - 6 Tesla), which provides the possibility to check Heisenberg-Euler scatter of high energy photons.

  13. In Situ Synchrotron X-Ray Diffraction and Small Angle X-Ray Scattering Studies on Rapidly Heated and Cooled Ti-Al and Al-Cu-Mg Alloys Using Laser-Based Heating

    Science.gov (United States)

    Kenel, C.; Schloth, P.; Van Petegem, S.; Fife, J. L.; Grolimund, D.; Menzel, A.; Van Swygenhoven, H.; Leinenbach, C.

    2016-03-01

    Beam-based additive manufacturing (AM) typically involves high cooling rates in a range of 103-104 K/s. Therefore, new techniques are required to understand the non-equilibrium evolution of materials at appropriate time scales. Most technical alloys have not been optimized for such rapid solidification, and microstructural, phase, and elemental solubility behavior can be very different. In this work, the combination of complementary in situ synchrotron micro-x-ray diffraction (microXRD) and small angle x-ray scattering (SAXS) studies with laser-based heating and rapid cooling is presented as an approach to study alloy behavior under processing conditions similar to AM techniques. In rapidly solidified Ti-48Al, the full solidification and phase transformation sequences are observed using microXRD with high temporal resolution. The high cooling rates are achieved by fast heat extraction. Further, the temperature- and cooling rate-dependent precipitation of sub-nanometer clusters in an Al-Cu-Mg alloy can be studied by SAXS. The sensitivity of SAXS on the length scales of the newly formed phases allows their size and fraction to be determined. These techniques are unique tools to help provide a deeper understanding of underlying alloy behavior and its influence on resulting microstructures and properties after AM. Their availability to materials scientists is crucial for both in-depth investigations of novel alloys and also future production of high-quality parts using AM.

  14. Combining Single-Molecule Optical Trapping and Small-Angle X-Ray Scattering Measurements to Compute the Persistence Length of a Protein ER/K alpha-Helix

    DEFF Research Database (Denmark)

    Sivaramakrishnan, S.; Sung, J.; Ali, M.

    2009-01-01

    A relatively unknown protein structure motif forms stable isolated single alpha-helices, termed ER/K alpha-helices, in a wide variety of proteins and has been shown to be essential for the function of some molecular motors. The flexibility of the ER/K alpha-helix determines whether it behaves...... as a force transducer, rigid spacer, or flexible linker in proteins. In this study, we quantity this flexibility in terms of persistence length, namely the length scale over which it is rigid. We use single-molecule optical trapping and small-angle x-ray scattering, combined with Monte Carlo simulations...... to demonstrate that the Kelch ER/K alpha-helix behaves as a wormlike chain with a persistence length of similar to 15 nm or similar to 28 turns of alpha-helix. The ER/K alpha-helix length in proteins varies from 3 to 60 nm, with a median length of similar to 5 nm. Knowledge of its persistence length enables us...

  15. Structural dynamics and ssDNA binding activity of the three N-terminal domains of the large subunit of Replication Protein A from small angle X-ray scattering

    Energy Technology Data Exchange (ETDEWEB)

    Pretto, Dalyir I.; Tsutakawa, Susan; Brosey, Chris A.; Castillo, Amalchi; Chagot, Marie-Eve; Smith, Jarrod A.; Tainer, John A.; Chazin, Walter J.

    2010-03-11

    Replication Protein A (RPA) is the primary eukaryotic ssDNA binding protein utilized in diverse DNA transactions in the cell. RPA is a heterotrimeric protein with seven globular domains connected by flexible linkers, which enable substantial inter-domain motion that is essential to its function. Small angle X-ray scattering (SAXS) experiments on two multi-domain constructs from the N-terminus of the large subunit (RPA70) were used to examine the structural dynamics of these domains and their response to the binding of ssDNA. The SAXS data combined with molecular dynamics simulations reveal substantial interdomain flexibility for both RPA70AB (the tandem high affinity ssDNA binding domains A and B connected by a 10-residue linker) and RPA70NAB (RPA70AB extended by a 70-residue linker to the RPA70N protein interaction domain). Binding of ssDNA to RPA70NAB reduces the interdomain flexibility between the A and B domains, but has no effect on RPA70N. These studies provide the first direct measurements of changes in orientation of these three RPA domains upon binding ssDNA. The results support a model in which RPA70N remains structurally independent of RPA70AB in the DNA bound state and therefore freely available to serve as a protein recruitment module.

  16. Dietary iron-loaded rat liver haemosiderin and ferritin: in situ measurement of iron core nanoparticle size and cluster structure using anomalous small-angle x-ray scattering

    Science.gov (United States)

    Bovell, Eliza; Buckley, Craig E.; Chua-anusorn, Wanida; Cookson, David; Kirby, Nigel; Saunders, Martin; St. Pierre, Timothy G.

    2009-03-01

    The morphology, particle size distribution and cluster structure of the hydrated iron(III) oxyhydroxide particles associated with haemosiderin and ferritin in dietary iron-loaded rat liver tissue have been investigated using transmission electron microscopy (TEM) and anomalous small-angle x-ray scattering (ASAXS). Rat liver tissue was removed from a series of female Porton rats which had been fed an iron-rich diet until sacrifice at various ages from 2-24 months. Hepatic iron concentrations ranged from 1 to 65 mg Fe g-1 dry tissue. TEM studies showed both dispersed and clustered iron-containing nanoparticles. The dispersed particles were found to have mean sizes (±standard deviation) of 54 ± 8 Å for the iron-loaded animals and 55 ± 7 Å for the controls. Superposition of particles in TEM images prevented direct measurement of nanoparticulate size in the clusters. The ASAXS data were modelled to provide a quantitative estimate of both the size and spacing of iron oxyhydroxide particles in the bulk samples. The modelling yielded close-packed particles with sizes of 60 to 78 Å which when corrected for anomalous scattering suggests sizes from 54 to 70 Å. Particle size distributions are of particular importance since they determine the surface iron to core iron ratios, which in turn are expected to be related to the molar toxicity of iron deposits in cells.

  17. Contact Angle Goniometer

    Data.gov (United States)

    Federal Laboratory Consortium — Description:The FTA32 goniometer provides video-based contact angle and surface tension measurement. Contact angles are measured by fitting a mathematical expression...

  18. Why does acute primary angle closure happen? Potential risk factors for acute primary angle closure.

    Science.gov (United States)

    Zhang, Xiulan; Liu, Yaoming; Wang, Wei; Chen, Shida; Li, Fei; Huang, Wenbin; Aung, Tin; Wang, Ningli

    Acute primary angle closure is an ocular emergency and requires immediate management to avoid blindness. Narrow anterior chamber angle, advanced age, female gender, and Asian ethnic background are considered risk factors for acute primary angle closure. The predictive power of these factors is, however, relatively poor, and many questions remain unanswered because acute primary angle closure eventually develops in only a relatively small proportion of anatomically predisposed eyes. We summarize the potential roles of various factors in the pathogenesis of acute primary angle closure. Copyright © 2017 Elsevier Inc. All rights reserved.

  19. Structural stability of the square flux line lattice in YNi2B2C and LuNi2B2C studied with small angle neutron scattering

    DEFF Research Database (Denmark)

    Eskildsen, M.R.; Gammel, P.L.; Barber, B.P.

    1997-01-01

    We have studied the flux line lattice in YNi2B2C and LuNi2B2C, the nonmagnetic end members of the borocarbide superconductors using small angle neutron scattering and transport. For fields, H parallel to c, we find a square symmetric lattice which disorders rapidly above H/H-c2 similar to 0.2, well...

  20. Angles in Complex Vector Spaces

    OpenAIRE

    Scharnhorst, K.

    1999-01-01

    The article reviews some of the (fairly scattered) information available in the mathematical literature on the subject of angles in complex vector spaces. The following angles and their relations are considered: Euclidean, complex, and Hermitian angles, (Kasner's) pseudo-angle, the Kaehler angle (synonyms for the latter used in the literature are: angle of inclination, characteristic deviation, holomorphic deviation, holomorphy angle, Wirtinger angle, slant angle).

  1. Conformational variability of the stationary phase survival protein E from Xylella fastidiosa revealed by X-ray crystallography, small-angle X-ray scattering studies, and normal mode analysis.

    Science.gov (United States)

    Machado, Agnes Thiane Pereira; Fonseca, Emanuella Maria Barreto; Reis, Marcelo Augusto Dos; Saraiva, Antonio Marcos; Santos, Clelton Aparecido Dos; de Toledo, Marcelo Augusto Szymanski; Polikarpov, Igor; de Souza, Anete Pereira; Aparicio, Ricardo; Iulek, Jorge

    2017-10-01

    Xylella fastidiosa is a xylem-limited bacterium that infects a wide variety of plants. Stationary phase survival protein E is classified as a nucleotidase, which is expressed when bacterial cells are in the stationary growth phase and subjected to environmental stresses. Here, we report four refined X-ray structures of this protein from X. fastidiosa in four different crystal forms in the presence and/or absence of the substrate 3'-AMP. In all chains, the conserved loop verified in family members assumes a closed conformation in either condition. Therefore, the enzymatic mechanism for the target protein might be different of its homologs. Two crystal forms exhibit two monomers whereas the other two show four monomers in the asymmetric unit. While the biological unit has been characterized as a tetramer, differences of their sizes and symmetry are remarkable. Four conformers identified by Small-Angle X-ray Scattering (SAXS) in a ligand-free solution are related to the low frequency normal modes of the crystallographic structures associated with rigid body-like protomer arrangements responsible for the longitudinal and symmetric adjustments between tetramers. When the substrate is present in solution, only two conformers are selected. The most prominent conformer for each case is associated to a normal mode able to elongate the protein by moving apart two dimers. To our knowledge, this work was the first investigation based on the normal modes that analyzed the quaternary structure variability for an enzyme of the SurE family followed by crystallography and SAXS validation. The combined results raise new directions to study allosteric features of XfSurE protein. © 2017 Wiley Periodicals, Inc.

  2. Small angle neutron scattering study of magnetic clustering in (Pr{sub 0.55}Ca{sub 0.45})(Mn{sub 1-y}Cr{sub y})O{sub 3} manganites

    Energy Technology Data Exchange (ETDEWEB)

    Castellano, C., E-mail: carlo.castellano@unimi.it [Universita degli Studi di Milano, Dipartimento di Chimica, Via Golgi 19, 20133 Milano (Italy); Martinelli, A. [CNR-SPIN, C.so Perrone 24, 16152 Genova (Italy); Ferretti, M. [CNR-SPIN, C.so Perrone 24, 16152 Genova (Italy); Universita degli Studi di Genova, Dipartimento di Chimica e Chimica Industriale, Via Dodecaneso 31, 16146 Genova (Italy); Cimberle, M.R. [CNR-IMEM, Via Dodecaneso 33, 16146 Genova (Italy); Mondelli, C. [CNR-IOM-OGG and TOF at Institut Laue-Langevin, 6 rue Jules Horowitz, 38042 Genoble Cedex 9 (France)

    2012-11-25

    Highlights: Black-Right-Pointing-Pointer Magnetic clusters formation in (Pr{sub 0.55}Ca{sub 0.45})(Mn{sub 1-y}Cr{sub y})O{sub 3} manganites is pointed out. Black-Right-Pointing-Pointer We indicate that magnetic clusters formation is favoured by Mn/Cr substitution. Black-Right-Pointing-Pointer The importance of magnetic polarons in manganites phase behaviour is thus emphasized. Black-Right-Pointing-Pointer We tune by chemical substitution the weight of the different phase components. Black-Right-Pointing-Pointer Magnetic clusters formation in Mn/Cr substituted manganites results to be softened. - Abstract: In the present paper we report a small angle neutron scattering (SANS) study of magnetic clusters formation in (Pr{sub 0.55}Ca{sub 0.45})(Mn{sub 1-y}Cr{sub y})O{sub 3} (y = 0.00, 0.03, 0.06) manganites which was performed by analyzing, above and below the magnetic phase transitions, the momentum transfer q dependence of the SANS intensity on temperature and on the applied magnetic field 0 < H < 5 T. Thermal scans between 5 and 300 K in zero field, 1 and 5 T as well as isothermal field-scans at three different temperatures were collected in the suitable q range on each sample. These measurements allowed us to determine the spatial dimensions, density and distribution of the non-overlapping ferromagnetic clusters before, during and after their formation, both in the insulating high temperature and in the percolating low temperature phases. Our results indicate that the magnetic clusters formation is favoured by Mn/Cr partial substitution, thus emphasizing the importance of magnetic polarons in the natural tendency of manganites to phase separation and the possibility to tune by chemical substitution the relative weight of one phase component with respect to the other one.

  3. Specificity of the double-stranded RNA-binding domain from the RNA-activated protein kinase PKR for double-stranded RNA: insights from thermodynamics and small-angle X-ray scattering.

    Science.gov (United States)

    Patel, Sunita; Blose, Joshua M; Sokoloski, Joshua E; Pollack, Lois; Bevilacqua, Philip C

    2012-11-20

    The interferon-inducible, double-stranded (ds) RNA-activated protein kinase (PKR) contains a dsRNA-binding domain (dsRBD) and plays key roles in viral pathogenesis and innate immunity. Activation of PKR is typically mediated by long dsRNA, and regulation of PKR is disfavored by most RNA imperfections, including bulges and internal loops. Herein, we combine isothermal titration calorimetry (ITC), electrophoretic mobility shift assays, and small-angle X-ray scattering (SAXS) to dissect the thermodynamic basis for the specificity of the dsRBD termed "p20" for various RNAs and to detect any RNA conformational changes induced upon protein binding. We monitor binding of p20 to chimeric duplexes containing terminal RNA-DNA hybrid segments and a central dsRNA segment, which was either unbulged ("perfect") or bulged. The ITC data reveal strong binding of p20 to the perfect duplex (K(d) ~ 30 nM) and weaker binding to the bulged duplex (K(d) ~ 2-5 μM). SAXS reconstructions and p(r) distance distribution functions further uncover that p20 induces no significant conformational change in perfect dsRNA but largely straightens bulged dsRNA. Together, these observations support the dsRBD's ability to tightly bind to only A-form RNA and suggest that in a noninfected cell, PKR may be buffered via weak interactions with various bulged and looped RNAs, which it may straighten. This work suggests that PKR-regulating RNAs with complex secondary and tertiary structures likely mimic dsRNA and/or engage portions of PKR outside of the dsRBD.

  4. Pulsed Laser Ablation-Induced Green Synthesis of TiO2 Nanoparticles and Application of Novel Small Angle X-Ray Scattering Technique for Nanoparticle Size and Size Distribution Analysis.

    Science.gov (United States)

    Singh, Amandeep; Vihinen, Jorma; Frankberg, Erkka; Hyvärinen, Leo; Honkanen, Mari; Levänen, Erkki

    2016-12-01

    This paper aims to introduce small angle X-ray scattering (SAXS) as a promising technique for measuring size and size distribution of TiO2 nanoparticles. In this manuscript, pulsed laser ablation in liquids (PLAL) has been demonstrated as a quick and simple technique for synthesizing TiO2 nanoparticles directly into deionized water as a suspension from titanium targets. Spherical TiO2 nanoparticles with diameters in the range 4-35 nm were observed with transmission electron microscopy (TEM). X-ray diffraction (XRD) showed highly crystalline nanoparticles that comprised of two main photoactive phases of TiO2: anatase and rutile. However, presence of minor amounts of brookite was also reported. The traditional methods for nanoparticle size and size distribution analysis such as electron microscopy-based methods are time-consuming. In this study, we have proposed and validated SAXS as a promising method for characterization of laser-ablated TiO2 nanoparticles for their size and size distribution by comparing SAXS- and TEM-measured nanoparticle size and size distribution. SAXS- and TEM-measured size distributions closely followed each other for each sample, and size distributions in both showed maxima at the same nanoparticle size. The SAXS-measured nanoparticle diameters were slightly larger than the respective diameters measured by TEM. This was because SAXS measures an agglomerate consisting of several particles as one big particle which slightly increased the mean diameter. TEM- and SAXS-measured mean diameters when plotted together showed similar trend in the variation in the size as the laser power was changed which along with extremely similar size distributions for TEM and SAXS validated the application of SAXS for size distribution measurement of the synthesized TiO2 nanoparticles.

  5. Probing the surface microstructure of layer-by-layer self-assembly chitosan/poly(L-glutamic acid) multilayers: A grazing-incidence small-angle X-ray scattering study

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Nie; Yang, Chunming, E-mail: yangchunming@sinap.ac.cn; Wang, Yuzhu; Zhao, Binyu; Bian, Fenggang; Li, Xiuhong; Wang, Jie, E-mail: wangjie@sinap.ac.cn

    2016-01-01

    This study characterized the surface structure of layer-by-layer self-assembly chitosan/poly(L-glutamic acid) multilayers through grazing-incidence small-angle X-ray scattering (GISAXS), X-ray reflectivity (XRR), and atomic force microscopy (AFM). A weakly long-period ordered structure along the in-plane direction was firstly observed in the polyelectrolyte multilayer by the GISAXS technique. This structure can be attributed to the specific domains on the film surface. In the domain, nanodroplets that were formed by polyelectrolyte molecules were orderly arranged along the free surface of the films. This ordered structure gradually disappeared with the increasing bilayer number because of the complex merging behavior of nanodroplets into large islands. Furthermore, resonant diffuse scattering became evident in the GISAXS patterns as the number of bilayers in the polyelectrolyte multilayer was increased. Notably, the lateral cutoff length of resonant diffuse scattering for these polyelectrolyte films was comparable with the long-period value of the ordered nanodroplets in the polyelectrolyte multilayer. Therefore, the nanodroplets could be considered as a basic transmission unit for structure propagation from the inner interface to the film surface. It suggests that the surface structure with length scale larger than the size of nanodroplets was partially complicated from the interface structure near the substrate, but surface structure smaller than the cutoff length was mainly depended on the conformation of nanodroplets. - Highlights: • The growth of ordered nanodroplets in PEMs was characterized by the GISAXS technique. • The basic transmission units for structure propagation within PEMs were nanodroplets. • High-performance of wave-guiding devices prepared by PEMs was predicted.

  6. The quadriceps angle

    DEFF Research Database (Denmark)

    Miles, James Edward; Frederiksen, Jane V.; Jensen, Bente Rona

    2012-01-01

    OBJECTIVES: To evaluate the effect of measurement technique and limb positioning on quadriceps (Q) angle measurement, intra- and interobserver reliability, potential sources of error, and the effect of Q angle variation. STUDY DESIGN: Cadaveric radiographic study and computer modeling. ANIMALS......: Pelvic limbs from red foxes (Vulpes vulpes). METHODS: Q angles were measured on hip dysplasia (HD) and whole limb (WL) view radiographs of each limb between the acetabular rim, mid-point (Q1: patellar center, Q2: femoral trochlea), and tibial tuberosity. Errors of 0.5-2.0 mm at measurement landmarks...... alone and in combination were modeled to identify the effect on Q angle. The effect of measured Q angles on the medial force exerted on the patella (F(MEDIAL) ) was calculated. RESULTS: The HD position yielded significantly (P angles than the WL position. No significant difference...

  7. Angles in hyperbolic lattices

    DEFF Research Database (Denmark)

    Risager, Morten S.; Södergren, Carl Anders

    2017-01-01

    It is well known that the angles in a lattice acting on hyperbolic n -space become equidistributed. In this paper we determine a formula for the pair correlation density for angles in such hyperbolic lattices. Using this formula we determine, among other things, the asymptotic behavior of the den...

  8. Small C7-T1 lordotic angle and muscle degeneration at C7 level were independent radiological characteristics of patients with cervical imbalance: a propensity score-matched analysis.

    Science.gov (United States)

    Tamai, Koji; Romanu, Joshua; Grisdela, Phillip; Paholpak, Permsak; Zheng, Pengfei; Nakamura, Hiroaki; Buser, Zorica; Wang, Jeffrey C

    2018-01-31

    Cervical sagittal vertical axis (cSVA) of ≥40 mm is recognized as the key factor of poor health-related quality of life, poor surgical outcomes, and correction loss after surgery for cervical deformity. However, little is known about the radiological characteristics of patients with cSVA≥40 mm. The purpose of this study was to identify the radiological characteristics of patients with cervical imbalance. Retrospective analysis of weight-bearing cervical magnetic resonance (MR) images. Consecutive 1,500 MR images of symptomatic patients in weight-bearing position. Cervical sagittal vertical axis, cervical alignment, cervical balance parameters (T1 slope, Co-C2 angle, C2-C7 angle, C7-T1 angle, neck tilt, and thoracic inlet angle), disc degeneration (Pfirmann and Suzuki classification), end plate degeneration (Modic change), spondylolisthesis (antero- and retrolisthesis), anteroposterior (AP) diameter of dural sac, cross-sectional area (CSA), and fat infiltration ratio of the transversospinalis muscles at C4 and C7 levels. Patients were divided into two groups: cSVA≥40 mm and cSVAangle was smaller (pangle (adjusted odds ratio [aOR]=0.592, p=.001) and fat infiltration ratio at C7 level (aOR=1.178, p=.030) were significant independent variables. Smaller C7-T1 lordotic angle and severe muscle degeneration at C7 level were independent characteristics of patients with cervical imbalance. Copyright © 2018 Elsevier Inc. All rights reserved.

  9. Photoelectric angle converter

    Science.gov (United States)

    Podzharenko, Volodymyr A.; Kulakov, Pavlo I.

    2001-06-01

    The photo-electric angle transmitter of rotation is offered, at which the output voltage is linear function of entering magnitude. In a transmitter the linear phototransducer is used on the basis of pair photo diode -- operating amplifier, which output voltage is linear function of the area of an illuminated photosensitive stratum, and modulator of a light stream of the special shape, which ensures a linear dependence of this area from an angle of rotation. The transmitter has good frequent properties and can be used for dynamic measurements of an angular velocity and angle of rotation, in systems of exact drives and systems of autocontrol.

  10. The lateral angle revisited

    DEFF Research Database (Denmark)

    Morgan, Jeannie; Lynnerup, Niels; Hoppa, R.D.

    2013-01-01

    This article presents the results of a validation study of a previously published method of sex determination from the temporal bone. The purpose of this study was to evaluate the lateral angle method for the internal acoustic canal for accurately determining the sex of human skeletal remains using...... measurements taken from computed tomography (CT) scans. Previous reports have observed that the lateral angle size in females is significantly larger than in males. The method was applied to an independent series of 77 postmortem CT scans (42 males, 35 females) to validate its accuracy and reliability....... The mean lateral angle of the internal acoustic canal was found to be larger in females (46.5°) than in males (43.4°). However, the difference was not statistically significant and the sex differences reported in previous studies were not substantiated. In light of the observed results, the lateral angle...

  11. Angle-Ply Weaving

    Science.gov (United States)

    Farley, Gary L.

    1990-01-01

    Bias-direction or angle-ply weaving is proposed new process for weaving fibers along bias in conventional planar fabric or in complicated three-dimensional multilayer fabric preform of fiber-reinforced composite structure. Based upon movement of racks of needles and corresponding angle yarns across fabric as fabric being formed. Fibers woven along bias increases shear stiffness and shear strength of preform, increasing value of preform as structural member.

  12. Modified angle's classification for primary dentition

    Directory of Open Access Journals (Sweden)

    Kaushik Narendra Chandranee

    2017-01-01

    Full Text Available Aim: This study aims to propose a modification of Angle's classification for primary dentition and to assess its applicability in children from Central India, Nagpur. Methods: Modification in Angle's classification has been proposed for application in primary dentition. Small roman numbers i/ii/iii are used for primary dentition notation to represent Angle's Class I/II/III molar relationships as in permanent dentition, respectively. To assess applicability of modified Angle's classification a cross-sectional preschool 2000 children population from central India; 3–6 years of age residing in Nagpur metropolitan city of Maharashtra state were selected randomly as per the inclusion and exclusion criteria. Results: Majority 93.35% children were found to have bilateral Class i followed by 2.5% bilateral Class ii and 0.2% bilateral half cusp Class iii molar relationships as per the modified Angle's classification for primary dentition. About 3.75% children had various combinations of Class ii relationships and 0.2% children were having Class iii subdivision relationship. Conclusions: Modification of Angle's classification for application in primary dentition has been proposed. A cross-sectional investigation using new classification revealed various 6.25% Class ii and 0.4% Class iii molar relationships cases in preschool children population in a metropolitan city of Nagpur. Application of the modified Angle's classification to other population groups is warranted to validate its routine application in clinical pediatric dentistry.

  13. 3-D numerical study of the effect of Reynolds number and baffle angle on heat transfer and pressure drop of turbulent flow of air through rectangular duct of very small height

    Directory of Open Access Journals (Sweden)

    Abhijit Paul

    2016-09-01

    Full Text Available Present article illustrates a computational study of three-dimensional steady state heat transfer and high turbulent flow characteristics through a rectangular duct with constant heat fluxed upper wall and single rectangular cross-sectioned baffle insertion at different angles. RNG k–ɛ model along with standard wall function based computations has been accomplished applying the finite volume method, and SIMPLE algorithm has been executed for solving the governing equations. For a Reynolds number, Re of 10,000 to 50,000, Prandtl Number, Pr of 0.707 and baffle angle, α of 30°, 60°, 90°, 120°, 150°, computational studies are executed, centred onto the hydraulic diameter, Dh, test section and hydrodynamic entry length of the duct. Flow field has been solved using Ansys Fluent 14.0 software. Study exposes that baffled rectangular duct has a higher average Nusselt number, Nu and Darcy friction factor, f compared to a smooth rectangular duct. Nu as well as f are found to be maximum at 90° baffle angle. Results illustrate that both α and Re play a significant role in heat transfer as well as flow characteristics and also effects TEF. The correctness of the results attained in this study is corroborated by comparing the results with those existing in the literature for smooth rectangular duct within a precision of ±2% for f and ±4% for Nu.

  14. At Right Angles

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 17; Issue 9. At Right Angles. Shailesh A Shirali. Information and Announcements Volume 17 Issue 9 September 2012 pp 920-920. Fulltext. Click here to view fulltext PDF. Permanent link: http://www.ias.ac.in/article/fulltext/reso/017/09/0920-0920 ...

  15. A Different Angle on Perspective

    Science.gov (United States)

    Frantz, Marc

    2012-01-01

    When a plane figure is photographed from different viewpoints, lengths and angles appear distorted. Hence it is often assumed that lengths, angles, protractors, and compasses have no place in projective geometry. Here we describe a sense in which certain angles are preserved by projective transformations. These angles can be constructed with…

  16. Small-angle neutron scattering study of the flux-line lattice in a single crystal of Bi2.15Sr1.95CaCu2O8+x

    DEFF Research Database (Denmark)

    Yethiraj, M.; Mook, H.A.; Forgan, E.M.

    1994-01-01

    as the temperature is increased above a field‐dependent melting temperature. Diffracted intensity due to the vortex lattice also falls off as the applied field is increased. It is believed that this is a manifestation of the transition of the three‐dimensional flux lines into two‐dimensional pancake vortices......A flux‐line lattice (FLL) was observed in a single crystal of Bi2.15Sr1.95CaCu2O8+x (BSCCO) using small‐angle neutron scattering methods. The sample has a superconducting transition at 85 K. The flux‐line lattice is observed to melt, evidenced by the rapid disappearance of diffracted intensity...

  17. Relationship between the angle of repose and angle of internal ...

    African Journals Online (AJOL)

    Abstract. Click on the link to view the abstract. Keywords: Angle of repose, angle of internal friction, granular materials, triaxial compression machine, moisture content. Tanzania J. Agric. Sc. (1998) Vol.1 No.2, 187-194 ...

  18. Scaling of misorientation angle distributions

    DEFF Research Database (Denmark)

    Hughes, D.A.; Chrzan, D.C.; Liu, Q.

    1998-01-01

    The measurement of misorientation angle distributions following different amounts of deformation in cold-rolled aluminum and nickel and compressed stainless steel is reported. The sealing of the dislocation cell boundary misorientation angle distributions is studied. Surprisingly, the distributions...

  19. Effects of small specimen tilt and probe convergence angle on ADF-STEM image contrast of Si(0.8)Ge(0.2) epitaxial strained layers on (100) Si.

    Science.gov (United States)

    Wu, X; Robertson, M D; Kawasaki, M; Baribeau, J M

    2012-03-01

    The effects of specimen tilt and probe convergence angle on annular dark field (ADF) image contrast of Si(0.8)Ge(0.2) heteroepitaxial strained layers on (100) Si were investigated in a 200 kV scanning transmission electron microscope (STEM) for a TEM specimen thickness of 195 nm. With 0.5 degrees of specimen tilt away from the exact zone-axis orientation, the signal-to-noise level of atomic columns was significantly reduced for both Si(0.8)Ge(0.2) and Si in high resolution ADF-STEM lattice images. When the specimen was tilted 0.5 degrees around the axis, or the STEM probe convergence semiangle was reduced from 14.3 to 3.6 mrad, the ADF-STEM image intensity profiles across the Si(0.8)Ge(0.2) and Si layers changed significantly as compared to those obtained at the exact zone axis orientation, and no longer reflected the composition changes occurring across the layer structure. Multislice image simulation results revealed that the misfit strain between the Si(0.8)Ge(0.2) and Si layers, and strain relaxation near the surface of the TEM specimen, were responsible for the observed changes in image intensity. Crown Copyright © 2012. Published by Elsevier B.V. All rights reserved.

  20. Variable angle correlation spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Young Kyo [Univ. of California, Berkeley, CA (United States)

    1994-05-01

    In this dissertation, a novel nuclear magnetic resonance (NMR) technique, variable angle correlation spectroscopy (VACSY) is described and demonstrated with 13C nuclei in rapidly rotating samples. These experiments focus on one of the basic problems in solid state NMR: how to extract the wealth of information contained in the anisotropic component of the NMR signal while still maintaining spectral resolution. Analysis of the anisotropic spectral patterns from poly-crystalline systems reveal information concerning molecular structure and dynamics, yet in all but the simplest of systems, the overlap of spectral patterns from chemically distinct sites renders the spectral analysis difficult if not impossible. One solution to this problem is to perform multi-dimensional experiments where the high-resolution, isotropic spectrum in one dimension is correlated with the anisotropic spectral patterns in the other dimensions. The VACSY technique incorporates the angle between the spinner axis and the static magnetic field as an experimental parameter that may be incremented during the course of the experiment to help correlate the isotropic and anisotropic components of the spectrum. The two-dimensional version of the VACSY experiments is used to extract the chemical shift anisotropy tensor values from multi-site organic molecules, study molecular dynamics in the intermediate time regime, and to examine the ordering properties of partially oriented samples. The VACSY technique is then extended to three-dimensional experiments to study slow molecular reorientations in a multi-site polymer system.