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Sample records for nasicon type structure

  1. A systematic study of Nasicon-type Li-i + XMXTi2 _ x(PO4)(3) (M: Cr, Al, Fe) by neutron diffraction and impedance spectroscopy.

    Czech Academy of Sciences Publication Activity Database

    Pérez-Estébanez, Marta; Isasi-Marín, J.; Többens, D. M.; Rivera-Calzada, A.; León, C.

    2014-01-01

    Ro?. 266, 15 November (2014), s. 1-8. ISSN 0167-2738 R&D Projects: GA MŠk(CZ) LO1219 Keywords : nasicon-type structure * neutron diffraction * ionic conductivity * occupation factor Subject RIV: AL - Art, Architecture, Cultural Heritage Impact factor: 2.112, year: 2013 http://www.sciencedirect.com/science/journal/01672738/266

  2. Electrical Properties of NASICON-type Structured Li1.3Al0.3Ti1.7(PO4)3 Solid Electrolyte Prepared by 1,2-Propylene glycol-assisted Sol-gel Method

    Science.gov (United States)

    Zhang, Lin-chao; Chen, Peng; Hu, Zhang; Chen, Chun-hua

    2012-12-01

    Lithium-ion conductor Li1.3Al0.3Ti1.7(PO4)3 with an ultrapure NASICON-type phase is synthesized by a 1,2-propylene glycol (1,2-PG)-assisted sol-gel method and characterized by differential thermal analysis-thermo gravimetric analysis, X-ray diffraction, scanning electron microscopy, electrochemical impedance spectroscopy, and chronoamperometry test. Due to the use of 1,2-PG, a homogeneous and light yellow transparent precursor solution is obtained without the precipitation of Ti4+ and Al3+ with PO43-. Well crystallized Li1.3Al0.3Ti1.7(PO4)3 can be prepared at much lower temperatures from 850 °C to 950 °C within a shorter synthesis time compared with that prepared at a temperature above 1000 °C by a conventional solid-state reaction method. The lithium ionic conductivity of the sintered pellets is up to 0.3 mS/cm at 50 °C with an activation energy as low as 36.6 kJ/mol for the specimen pre-sintered at 700 °C and sintered at 850 °C. The high conductivity, good chemical stability and easy fabrication of the Li1.3Al0.3Ti1.7(PO4)3 provide a promising candidate as solid electrolyte for all-solid-state Li-ion rechargeable batteries.

  3. Hydrothermal synthesis, structural and physico-chemical characterizations of two Nasicon phosphates: M0.50IITi2(PO4)3 (M = Mn, Co)

    International Nuclear Information System (INIS)

    The family of titanium Nasicon-phosphates of generic formula M0.5IITi2(PO4)3 has been revisited using hydrothermal techniques. Two phases have been synthesized: Mn0.5IITi2(PO4)3 (MnTiP) and Co0.5IITi2(PO4)3 (CoTiP). Single crystal diffraction studies show that they exhibit two different structural types. Mn0.5IITi2(PO4)3 phosphate crystallizes in the R-3 space group, with the cell parameters a = 8.51300(10) A and c = 21.0083(3) A (V = 1318.52(3) A3 and Z = 6). The Co0.5IITi2(PO4)3 phosphate crystallizes in the R-3c space group, with a = 8.4608(9) A and c = 21.174(2) A (V = 1312.7(2) A3 and Z = 6). These two compounds are clearly related to the parent Nasicon-type rhombohedral structure, which can be described using [Ti2(PO4)3] framework composed of two [TiO6] octahedral interlinked via three [PO4] tetrahedra. 31P magic-angle spinning nuclear magnetic resonance (MAS-NMR) data are presented as supporting data. Curie-Weiss-type behavior is observed in the magnetic susceptibility. The phases are also characterized by IR spectroscopy and UV-visible.

  4. Double NASICON-type cell: ordered Nd3+ distribution in Li0.2Nd0.8/3Zr2(PO4)3.

    Science.gov (United States)

    Barré, Maud; Crosnier-Lopez, Marie-Pierre; Le Berre, Françoise; Bohnké, Odile; Suard, Emmanuelle; Fourquet, Jean-Louis

    2008-06-21

    The NASICON compound Li(0.2)Nd(0.8/3)Zr(2)(PO(4))(3), synthesized by a sol-gel process, has been structurally characterized by TEM and powder diffraction (neutron and X-ray). It crystallizes in the space group R3[combining macron] (No. 148): at room temperature, the Nd(3+) ions present an ordered distribution in the [Zr(2)(PO(4))(3)](-) network which leads to a doubling of the classical c parameter (a = 8.7160(3) A, c = 46.105(1) A). Above 600 degrees C, Nd(3+) diffusion occurs leading at 1000 degrees C to the loss of the supercell. This reversible cationic diffusion in a preserved 3D [Zr(2)(PO(4))(3)](-) network is followed through thermal X-ray diffraction. Ionic conductivity measurements have been undertaken by impedance spectroscopy, while some results concerning the sintering of the NASICON compound are given. PMID:18521448

  5. Hydrothermal synthesis, structural and physico-chemical characterizations of two Nasicon phosphates: M0,50IITi2(PO4)3 (M = Mn, Co).

    Czech Academy of Sciences Publication Activity Database

    Essehli, R.; El Bali, B.; Benmokhtar, S.; Fejfarová, Karla; Dušek, Michal

    2009-01-01

    Ro?. 44, ?. 7 (2009), s. 1502-15010. ISSN 0025-5408 R&D Projects: GA ?R GA202/06/0757 Institutional research plan: CEZ:AV0Z10100521 Keywords : X-ray diffraction * Jana 2006 * Nasicon-phosphates Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.879, year: 2009

  6. Equilibrium relations in the system TiO2/V2O5/P2O5 and crystal structure of a NASICON-related vanadyl(V) titanium(IV) phosphate

    International Nuclear Information System (INIS)

    Vanadyl(V)–titanium–orthophosphate (VVO)TiIV6(PO4)9 is formed by solid state reactions in the temperature range 525???780 °C. At higher temperature decomposition into V2O5 and the hitherto unknown solid solution Ti(P1?xVx)2O7 (0?x?0.23; 0.30?x?0.43) is observed. The process of phase formation has been monitored by MAS-NMR (31P, 51V) spectroscopy. Equilibrium phase relations in the quaternary system TiO2/VO2.5/PO2.5 have been determined. A structure analysis from X-ray single-crystal data (P63/m (No. 176), Z=2; a=8.4438(3) Å, c=22.215(1) Å, 14 independent atoms, 87 variables, 2066 unique reflections, R1=0.032, wR2=0.084) shows the relationship of (VVO)TiIV6(PO4)9 to the NASICON structure family. In marked contrast to the other members of this family [TiIV2O9] double-octahedra and strongly distorted tetrahedral [(VV=O)O3] groups are observed besides isolated [TiIVO6] octahedra and phosphate tetrahedra. The structure model is in agreement with the results from MAS-NMR (31P, 51V) spectroscopy. - Graphical abstract: (VVO)TiIV6(PO4)9 belongs to the NASICON structu the NASICON structure family. Its structure contains [TiIV2O9] double-octahedra and unprecedented, strongly distorted tetrahedral [(VV=O)O3] groups, in stark contrast to other members of this family. The structure model is in agreement with the results from MAS-NMR (31P, 51V) spectroscopy. Highlights: ? Equilibrium relations for the subsolidus have been established for the system TiO2/V2O5/P2O5. ? Phase formation has been monitored by XRPD as well as by 31P- and 51-MAS-NMR. ? A solid solution Ti(P1?xVx)2O7 exists up to x=0.43 with a miscibility gap at 0.23?x?0.30. ? The crystal structure of the new NASICON-related phosphate (VVO)TiIV6(PO4)9 is reported. ? The crystal structure contains the unprecedented [(V=O)O3] group.

  7. Synthesis of Li{sub 1}+xM{sup I}II{sub x}Ti{sub 2}-x(PO{sub 4}){sub 3} with nasicon structure, using sol-gel methods. Study of the relationship microstructure electrical properties; Sintesis mediante quimica sol gel de compuestos Li{sub 1}+xM{sup I}II{sub x}Ti{sub 2}-x(PO{sub 4}){sub 3} con estructura tipo Nasicon. Estudio de la relacion microestructura-propiedades electricas

    Energy Technology Data Exchange (ETDEWEB)

    Perez-Estebanez, M.; Rivera-Calzada, A.; Leon, C.; Santamaria, J.; Isasi-Marin, J.

    2010-07-01

    Compounds of formula Li{sub 1}+xM{sup I}II{sub x}Ti{sub 2}-x(PO{sub 4}){sub 3} with M{sup I}II = Cr, Fe and x = 0 and 0.05 have been prepared at soft temperatures using the Pechini synthesis method, based on sol-gel chemistry. The structural and microstructural characterization by X-ray diffraction and Scanning Electron Microscopy (SEM), shows that all of them crystallize in a NASICON-type structure with similar lattice parameters. Doping with Fe and Cr, causes an increase of the density of the samples after sinterization what clearly improves the ionic conductivity of the original material, LiTi{sub 2}(PO{sub 4}){sub 3} until values of 9x10{sup -}4 S cm{sup -}1 at room temperature in the chromium-doped material. (Author)

  8. Synthesis, structure and characterisation of Fe0.50Ti2(PO4)3: A new material with Nasicon-like structure

    International Nuclear Information System (INIS)

    A new iron titanyl phosphate Fe0.50Ti2(PO4)3 was synthesized by both solid-state reaction and Cu2+-Fe2+ ion exchange method. The material was then characterized by X-ray diffraction, Mossbauer, magnetic susceptibility measurements and optical absorption. The crystal structure of the compound was refined, using X-ray powder diffraction data, by the Rietveld profile method; it crystallizes in the rhombohedral system, space group R3-bar, with a=8.511(1)A and c=20.985(3)A, V=1316.45(3)A3 and Z=6. The structure, which is compared to that of Mn0.50Ti2(PO4)3 is built up from [TiO6] octahedra and [PO4] tetrahedra which are linked by corner sharing along the c-axis. Fe2+ cations are located in half of the antiprism MI sites and are orderly distributed with vacancies within the two possible positions of the MI sites of R3-bar. These results were supported by the Mossbauer studies that showed the presence of one Fe2+ site in the high spin state (t2g4eg2). The Curie-Weiss-type behavior is observed in the magnetic susceptibility. Diffuse reflectance spectrum indicates the presence of octahedrally coordinated Fe2+ ions

  9. NASICON-related Na3.4Mn0.4Fe1.6(PO43

    Directory of Open Access Journals (Sweden)

    Nikolay S. Slobodyanik

    2012-07-01

    Full Text Available The solid solution, sodium [iron(III/manganese(II] tris(orthophosphate, Na3.4Mn0.4Fe1.6(PO43, was obtained using a flux method. Its crystal structure is related to that of NASICON-type compounds. The [(Mn/Fe2(PO43] framework is built up from an (Mn/FeO6 octahedron (site symmetry 3., with a mixed Mn/Fe occupancy, and a PO4 tetrahedron (site symmetry .2. The Na+ cations are distributed over two partially occupied sites in the cavities of the framework. One Na+ cation (site symmetry -3. is surrounded by six O atoms, whereas the other Na+ cation (site symmetry .2 is surrounded by eight O atoms.

  10. Restrictions to obtain NASICON by a ceramic route

    Directory of Open Access Journals (Sweden)

    Fuentes, R. O.

    2004-08-01

    Full Text Available Highly reactive monoclinic ZrO2 powders were mixed with Na3PO4•12H2O and amorphous SiO2 in the stoichiometric quantities to obtain Na3Zr2Si2PO12. The mixtures were calcined at different temperatures (Tcalc and for variable periods of time (tcalc. Their morphology was analysed by SEM and the composition by powder XRD. NASICON reflections are not detected for Tcalc=900°C and for relatively short tcalc values of 2 h. At 1100°C, the onset of low intensity NASICON peaks indicate the early stages of the formation reaction which is significantly enhanced when Tcalc increases up to 1200 and 1300°C. For higher temperatures, an apparent decrease of the reaction rate is suggested. On the other hand, the intensities of the ZrO2 peaks suffer a drastic decrease when Tcalc varies from 900 to 1300°C, followed by a slight increase for Tcalc=1400°C. The studies were extended for mixtures kept in isothermal conditions at 1100, 1200 and 1300°C during 0.5, 1, 2, 4, 8 and 16 h. In the three temperatures, the increase of the tcalc up to ca. 4 h leads to a significant increase in the intensity of the NASICON reflections while that of mZrO2 decreases. A plateau is apparent for higher tcalc values suggesting that equilibrium may be attained. The use of a highly reactive tetragonal zirconia powder (also thermodynamically unstable at low temperature clearly improved the overall reaction extension and kinetics at moderate temperatures, yielding a single phase product.

    Polvos de ZrO2 monoclínica altamente reactivos fueron mezclados con Na3PO4•12H2O y SiO2 amorfo en cantidades apropiadas para obtener Na3Zr2Si2PO12. Las mezclas fueron calcinadas a diferentes temperaturas (Tcalc y diferentes tiempos (tcalc y caracterizadas por SEM y DRX. Líneas características del NASICON no son detectadas a Tcalc=900°C y a tiempos de calcinado relativamente cortos (< 2h. A 1100°C, la presencia de picos de NASICON de baja intensidad indica los primeros momentos de la reacción de formación, la cual es significativamente mejorada cuando Tcalc es aumentada a 1200 y 1300°C. Para altas temperaturas (< 1300ºC, se sugiere una aparente disminución de la velocidad de reacción. Por otra parte, la intensidad de los picos de ZrO2 sufren una drástica disminución cuando Tcalc varía desde 900 a 1300°C, seguido de un leve incremento a Tcalc=1400°C. Los estudios fueron realizados manteniendo condiciones isotérmicas a 1100, 1200 y 1300°C durante 0,5, 1, 2, 4, 8 y 16 h. En las tres temperaturas, el aumento de tcalc hasta 4 h conduce a un marcado aumento de la intensidad de las líneas características del NASICON, mientras que las correspondientes a mZrO2 disminuyen. Un “plateau” es observado a valores altos de tcalc, lo que sugiere que un equilibrio está siendo alcanzado. La utilización de polvos altamente reactivos de ZrO2 tetragonal (termodinámicamente inestable a baja temperatura mejoró claramente la extensión y la cinética de reacción a temperaturas moderadas, conduciendo a la formación de un producto monofásico.

  11. A type A structure in Khovanov Homology

    OpenAIRE

    Roberts, Lawrence P.

    2013-01-01

    Inspired by bordered Floer homology, we describe a type A structure on a Khovanov homology for a tangle, which complements the type D structure in a previous paper. The type A structure is a differential module over a certain algebra. This can be paired with the type D structure to recover the Khovanov chain complex. The homotopy type of the type A structure is a tangle invariant, and homotopy equivalences of the type A structure result in chain homotopy equivalences on the ...

  12. Parsing with Typed Feature Structures

    OpenAIRE

    Wintner, Shuly; Francez, Nissim

    1996-01-01

    In this paper we provide for parsing with respect to grammars expressed in a general TFS-based formalism, a restriction of ALE. Our motivation being the design of an abstract (WAM-like) machine for the formalism, we consider parsing as a computational process and use it as an operational semantics to guide the design of the control structures for the abstract machine. We emphasize the notion of abstract typed feature structures (AFSs) that encode the essential information o...

  13. Parsing with Typed Feature Structures

    CERN Document Server

    Wintner, S; Wintner, Shuly; Francez, Nissim

    1996-01-01

    In this paper we provide for parsing with respect to grammars expressed in a general TFS-based formalism, a restriction of ALE. Our motivation being the design of an abstract (WAM-like) machine for the formalism, we consider parsing as a computational process and use it as an operational semantics to guide the design of the control structures for the abstract machine. We emphasize the notion of abstract typed feature structures (AFSs) that encode the essential information of TFSs and define unification over AFSs rather than over TFSs. We then introduce an explicit construct of multi-rooted feature structures (MRSs) that naturally extend TFSs and use them to represent phrasal signs as well as grammar rules. We also employ abstractions of MRSs and give the mathematical foundations needed for manipulating them. We then present a simple bottom-up chart parser as a model for computation: grammars written in the TFS-based formalism are executed by the parser. Finally, we show that the parser is correct.

  14. Parsing with Typed Feature Structures

    CERN Document Server

    Wintner, S; Wintner, Shuly; Francez, Nissim

    1996-01-01

    In this paper we provide for parsing with respect to grammars expressed in a general TFS-based formalism, a restriction of ALE. Our motivation being the design of an abstract (WAM-like) machine for the formalism, we consider parsing as a computational process and use it as an operational semantics to guide the design of the control structures for the abstract machine. We emphasize the notion of abstract typed feature structures (AFSs) that encode the essential information of TFSs and define unification over AFSs rather than over TFSs. We then introduce an explicit construct of multi-rooted feature structures (MRSs) that naturally extend TFSs and use them to represent phrasal signs as well as grammar rules. We also employ abstractions of MRSs and give the mathematical foundations needed for manipulating them. We formally define grammars and the languages they generate, and then describe a model for computation that corresponds to bottom-up chart parsing: grammars written in the TFS-based formalism are executed...

  15. Abstract Machine for Typed Feature Structures

    OpenAIRE

    Wintner, Shuly; Francez, Nissim

    1995-01-01

    This paper describes an abstract machine for linguistic formalisms that are based on typed feature structures, such as HPSG. The core design of the abstract machine is given in detail, including the compilation process from a high-level language to the abstract machine language and the implementation of the abstract instructions. The machine's engine supports the unification of typed, possibly cyclic, feature structures. A separate module deals with control structures and in...

  16. Catalyst system of the structured type:

    OpenAIRE

    Jansen, J. C.; Legein, C. H.; Calis, H. P. A.; Bekkum, H.; Gerritsen, A. W.; Den Bleek, M.

    1994-01-01

    The invention relates to a catalyst system of the structured type, in which a structured support is covered with a layer of molecular sieve crystals and/or modifications thereof. These crystals have substantially the same orientation relative to the support surface. The invention further relates to a reactor in which this catalyst system is incorporated. Finally, the invention relates to a method for the selective reduction of nitrogen oxides utilizing a compound comprising a NH group, in whi...

  17. Structural study of colquiriite-type fluorides

    Science.gov (United States)

    Ono, Yasuhiro; Nakano, Kenji; Shimamura, Kiyoshi; Fukuda, Tsuguo; Kajitani, Tsuyoshi

    2001-07-01

    Structure parameters of the colquiriite-type fluorides LiCaAlF 6 LiSrAlF 6 and LiSrGaF 6 were studied by means of single crystal X-ray diffraction. Absorption and fluorescence spectra of the Ce-doped fluorides were also measured for correlation with structure differences. The 5d-4f emission spectrum slightly shifts toward the long wavelength side as the distortion around a dopant site becomes appreciable.

  18. Dual Lie bialgebra structures of Poisson types

    Science.gov (United States)

    Song, Guang'Ai; Su, YuCai

    2015-06-01

    Let $A=F[x,y]$ be the polynomial algebra on two variables $x,y$ over an algebraically closed field $F$ of characteristic zero. Under the Poisson bracket, $A$ is equipped with a natural Lie algebra structure. It is proven that the maximal good subspace of $A^*$ induced from the multiplication of the associative commutative algebra $A$ coincides with the maximal good subspace of $A^*$ induced from the Poisson bracket of the Poisson Lie algebra $A$. Based on this, structures of dual Lie bialgebras of the Poisson type are investigated. As by-products, five classes of new infinite dimensional Lie algebras are obtained.

  19. Insertion of Li, Na, K, Rb, and Cs in the unfilled structure of Nb2(PO4)3

    International Nuclear Information System (INIS)

    For studying intercalation of alkali metal ions (M = Li-Cs) into niobium (4, 5) orthophosphate of the composition Nb2(PO4)3 (1) a method was developed for synthesizing orthophosphates of the series MxNb1+x4+Nb1-x5+ (PO4)3 (2) and matrix of 1 from open systems of condensed phosphorus acids. The compounds prepared were characterized by data of chemical, thermal and X-ray phase analyses, as well as by IR spectroscopy. It was ascertained that both matrix of 1 and the entire series of interstitial solid solutions of 2 belong to the NASICON structural type. Introduction of alkali metal, irrespective of its radius and polarizing ability, promotes stabilization of niobium (4) oxidation state and formation of substituted orthophosphates of 2 of a fixed composition

  20. Interference enhanced thermoelectricity in quinoid type structures

    Science.gov (United States)

    Strange, M.; Seldenthuis, J. S.; Verzijl, C. J. O.; Thijssen, J. M.; Solomon, G. C.

    2015-02-01

    Quantum interference (QI) effects in molecular junctions may be used to obtain large thermoelectric responses. We study the electrical conductance G and the thermoelectric response of a series of molecules featuring a quinoid core using density functional theory, as well as a semi-empirical interacting model Hamiltonian describing the ?-system of the molecule which we treat in the GW approximation. Molecules with a quinoid type structure are shown to have two distinct destructive QI features close to the frontier orbital energies. These manifest themselves as two dips in the transmission, that remain separated, even when either electron donating or withdrawing side groups are added. We find that the position of the dips in the transmission and the frontier molecular levels can be chemically controlled by varying the electron donating or withdrawing character of the side groups as well as the conjugation length inside the molecule. This feature results in a very high thermoelectric power factor S2G and figure of merit ZT, where S is the Seebeck coefficient, making quinoid type molecules potential candidates for efficient thermoelectric devices.

  1. Interference enhanced thermoelectricity in quinoid type structures.

    Science.gov (United States)

    Strange, M; Seldenthuis, J S; Verzijl, C J O; Thijssen, J M; Solomon, G C

    2015-02-28

    Quantum interference (QI) effects in molecular junctions may be used to obtain large thermoelectric responses. We study the electrical conductance G and the thermoelectric response of a series of molecules featuring a quinoid core using density functional theory, as well as a semi-empirical interacting model Hamiltonian describing the ?-system of the molecule which we treat in the GW approximation. Molecules with a quinoid type structure are shown to have two distinct destructive QI features close to the frontier orbital energies. These manifest themselves as two dips in the transmission, that remain separated, even when either electron donating or withdrawing side groups are added. We find that the position of the dips in the transmission and the frontier molecular levels can be chemically controlled by varying the electron donating or withdrawing character of the side groups as well as the conjugation length inside the molecule. This feature results in a very high thermoelectric power factor S(2)G and figure of merit ZT, where S is the Seebeck coefficient, making quinoid type molecules potential candidates for efficient thermoelectric devices. PMID:25725747

  2. Synthesis of nano structured particles for Li-ion cathodic and anodic materials obtained by spray pyrolysis; Sintesis de particulas nanoestructuradas para materiales catodicos y anodicos obtenidos mediante Spray Prolisis

    Energy Technology Data Exchange (ETDEWEB)

    Gomez, L. S.; Meatza, I. de; Martin, M. I.; Boynao, I.; Cantero, I.; Rabanal, M. E.

    2010-07-01

    The development of the nano technology has contributed to improve the electrochemical properties in rechargeable batteries. The Spray Pyrolysis method allows to obtain nano structured materials with spherical morphology, narrow particle size distribution and compositional homogeneity. Nano structured particles have been prepared in this work to be used as anodic and cathodic materials in lithium-ion batteries. Among the cathodic materials, the Na-Si-Con (Li{sub 3}Fe{sub 2}(PO{sub 4}){sub 3}) structure and the olivine (LiFePO{sub 4}) phases have been synthesised. The Na-Si-Con iron phosphate favours the accommodation of the ion host, the diffusion and thermal stability. The olivine structure has an open three-dimensional network, favourable for hosting Lithium ions. The characterization by X ray diffraction, electron microscopy (scanning and transmission) and electron diffraction have allowed to identify a mix of crystalline phases of LiFePO{sub 4} (Olivine) and Li{sub 3}Fe{sub 2}(PO{sub 4}){sub 3} (Na-Si-Con). Thermal treatments produce porous particles. The tryphilite phase (olivine) appears after a thermal treatment at 800 degree centigrade/12h. Electrochemical results confirm the presence of the Na-Si-Con and olivine phases. Among the materials for being used as anode, the titanium oxides have been classified as good candidates as lithium ion host. The synthesis results in different experimental conditions for obtaining spherical and nano structured titanium oxide particles are presented. (Author)

  3. Comments on structural types of toroidal carbon nanotubes

    CERN Document Server

    Chuang, Chern; Jin, Bih-Yaw

    2012-01-01

    We clarify the relationships between the eight structural types of toroidal carbon nanotubes (TCNTs), which can be identified as the eight corners of a cube of structural transformation. The four families with Dnh symmetry can be related by rim rotations, and the same is true for those with Dnd symmetries. These two sets are then connected by horizontal shiftings, thereby completing the cube. Moreover, we further point out that there are five more highly symmetric Dnh structural types that can be derived from performing the generalized Stone-Wales transformatoin on certain TCNTs with Dnh structural types.

  4. Weakly-nonlocal Symplectic Structures, Whitham method, and weakly-nonlocal Symplectic Structures of Hydrodynamic Type

    OpenAIRE

    Maltsev, A. Ya.

    2004-01-01

    We consider the special type of the field-theoretical Symplectic structures called weakly nonlocal. The structures of this type are in particular very common for the integrable systems like KdV or NLS. We introduce here the special class of the weakly nonlocal Symplectic structures which we call the weakly nonlocal Symplectic structures of Hydrodynamic Type. We investigate then the connection of such structures with the Whitham averaging method and propose the procedure of "...

  5. Recent structures of various types of phosphaboranes.

    Czech Academy of Sciences Publication Activity Database

    Hnyk, Drahomír; Štíbr, Bohumil

    Erice : International School of Crystallography, 2001. s. 337. [ Strength from Weakness : Structural Consequences of Weak Interactions in Molecules, Supermolecules and Crystals /32./. 23.05.2001-03.06.2001, Erice] R&D Projects: GA AV ?R IAA4032804; GA MŠk LN00A028 Keywords : boranes * ab initio NMR method Subject RIV: CA - Inorganic Chemistry

  6. Types and Functions of Coastal Structures

    DEFF Research Database (Denmark)

    Burcharth, H. F.; A. Hughes, Steven

    2003-01-01

    Coastal structures are used in coastal defence schemes with the objective of preventing shoreline erosion and flooding of the hinterland. Other objectives include sheltering of harbour basins and harbour entrances against waves, stabilization of navigation channels at inlets, and protection of water intakes and outfalls.

  7. Stochastic Fatigue Analysis of Jacket Type Offshore Structures

    OpenAIRE

    Sigurdsson, Gudfinnur

    2010-01-01

    In this paper, a stochastic reliability assessment for jacket type offshore structures subjected to wave loads in deep water environments is outlined. In the reliability assessment, structural and loading uncertainties are taken into account by means of some stochastic variables. To estimate statistical measures of structural stress variations the modal spectral analysis method is applied.

  8. Reactor structure of LMFBR type reactor

    International Nuclear Information System (INIS)

    In an LMFBR type reactor, a flow channel hole for connecting an intermediate plenum and a low pressure plenum and a pipe for connecting a lower plenum and a cover gas space above the free coolant level are disposed in a reactor core vessel, and a liquid level indicator is disposed at the upper end of the pipe. If a leak preceding type crack is caused in a reactor core support cone partitioning the intermediate plenum and the lower plenum, coolants leak and flow out of the cracked portion to the lower plenum. Since leaked and flown coolants raise the liquid level in the pipe which keeps the height identical with that of the free coolant level during usual operation, the elevation of the liquid level is detected by the liquid level indicator, and failure of the reactor core support cone is prevented. Further, the reactor can be shutdown safely before it leads to accidents by using the liquid level elevation detection signal sent from the liquid indicator as a reactor shutdown signal. (N.H.)

  9. The market for HTGR type reactors with modular structure

    International Nuclear Information System (INIS)

    After a brief explanation relating to the fields of application of the HTGR type reactors with modular structures, the author refers to the specific costs of the system, its profitability, and the market potential, both domestic and abroad. (UA)

  10. Soil structure interactions of eastern U.S. type earthquakes

    International Nuclear Information System (INIS)

    Two types of earthquakes have occurred in the eastern US in the past. One of them was the infrequent major events such as the 1811-1812 New Madrid Earthquakes, or the 1886 Charleston Earthquake. The other type was the frequent shallow earthquakes with high frequency, short duration and high accelerations. Two eastern US nuclear power plants, V.C Summer and Perry, went through extensive licensing effort to obtain fuel load licenses after this type of earthquake was recorded on sites and exceeded the design bases beyond 10 hertz region. This paper discusses the soil-structure interactions of the latter type of earthquakes

  11. Interspecies radioimmunoassay for the major structural proteins of primate type-D retroviruses

    International Nuclear Information System (INIS)

    A competition radioimmunoassay has been developed in which type-D retroviruses from three primate species compete. The assay utilizes the major structural protein (36,000 daltons) of the endogenous squirrel monkey retrovirus and antisera directed against the major structural protein (27,000 daltons) of the Mason-Pfizer monkey virus isolated from rhesus monkeys. Purified preparations of both viruses grown in heterologous cells, as well as extracts of heterologous cells infected with squirrel monkey retrovirus or Mason-Pfizer monkey virus, compete completely in the assay. Addition of an endogenous virus of the langur monkey also results in complete blocking. No blocking in the assay is observed with type-C baboon viruses, woolly monkey virus, and gibbon virus. Various other type-C and type-B viruses also showed no reactivity. An interspecies assay has thus been developed that recognizes the type-D retroviruses from both Old World monkey (rhesus and langur) and New World monkey (squirrel) species

  12. A Quasi-Type-1 Phase-Locked Loop Structure

    DEFF Research Database (Denmark)

    Golestan, Saeed; Fernandez, Francisco Daniel Freijedo

    2014-01-01

    The grid voltage phase and frequency are crucial information in control of most grid connected power electronic based equipment. Most often, a phase-locked loop (PLL) is employed for this purpose. A PLL is a closed-loop feedback control system that the phase of its output signal is related to the phase of its input signal. Arguably, the simplest PLL is a type-1 PLL. The type-1 PLLs are characterized by having only one integrator in their control loop and therefore having a high stability margin. However, they suffer from a serious drawback: they cannot achieve zero average steady-state phase-error in the presence of frequency drifts. To overcome this drawback of type-1 PLLs, and at the same time, to achieve a fast dynamic response and high filtering capability, a modified PLL structure is proposed in this letter. The proposed PLL has a similar structure to a type-1 PLL, but from the control point of view is a type-2 control system. For this reason, it is called the quasi-type-1 PLL (QT1-PLL). The effectiveness of the proposed PLL is confirmed through simulation and experimental results and comparison with standard PLLs.

  13. Extended, regular HI structures around early-type galaxies

    OpenAIRE

    Oosterloo, T.; Morganti, R.; Sadler, E. M.; Hulst, J. M.; Serra, P.

    2007-01-01

    We discuss the morphology and kinematics of the HI of a sample of 30 southern gas-rich early-type galaxies selected from the HI Parkes All-Sky Survey (HIPASS). This is the largest collection of high-resolution HI data of a homogeneously selected sample. Given the sensitivity of HIPASS, these galaxies represent the most HI-rich early-type galaxies. In two-thirds of the galaxies, we find the HI to be in a large, regular disk- or ring-like structure that in some cases is stro...

  14. Equipment and building structures ageing management for WWER type NPPs

    International Nuclear Information System (INIS)

    This report presents the working group 'Equipment and building structures ageing management for WWER type NPPs' activities. The analysis of experience in ageing management, recommendations for regulatory guidelines on ageing management, investigation of case studies, definition suitable communication channels among regulators for ageing related data are given. Analyses of water chemistry, inspection data (safety margins criteria), plugging criteria, volume and time of ECT implementation in all WWER countries are presented. The results of Working group activity show that it is advisable to concentrate efforts on: set up the permanent communication channel among regulators, collection of regulatory criteria for WWER type NPP key components based on understanding of ageing mechanisms and data collection

  15. Structure of type II dehydroquinase from Pseudomonas aeruginosa.

    Science.gov (United States)

    Reiling, Scott; Kelleher, Alan; Matsumoto, Monica M; Robinson, Gonteria; Asojo, Oluwatoyin A

    2014-11-01

    Pseudomonas aeruginosa causes opportunistic infections and is resistant to most antibiotics. Ongoing efforts to generate much-needed new antibiotics include targeting enzymes that are vital for P. aeruginosa but are absent in mammals. One such enzyme, type II dehydroquinase (DHQase), catalyzes the interconversion of 3-dehydroquinate and 3-dehydroshikimate, a necessary step in the shikimate pathway. This step is vital for the proper synthesis of phenylalanine, tryptophan, tyrosine and other aromatic metabolites. The recombinant expression, purification and crystal structure of catalytically active DHQase from P. aeruginosa (PaDHQase) are presented. Cubic crystals belonging to space group F23, with unit-cell parameters a=b=c=125.39?Å, were obtained by vapor diffusion in sitting drops and the structure was refined to an R factor of 16% at 1.74?Å resolution. PaDHQase is a prototypical type II DHQase with the classical flavodoxin-like ?/? topology. PMID:25372814

  16. Sound radiation characteristics of a box-type structure

    Science.gov (United States)

    Ran Lin, Tian; Pan, Jie

    2009-09-01

    The finite element and boundary element methods are employed in this study to investigate the sound radiation characteristics of a box-type structure. It has been shown [T.R. Lin, J. Pan, Vibration characteristics of a box-type structure, Journal of Vibration and Acoustics, Transactions of ASME 131 (2009) 031004-1-031004-9] that modes of natural vibration of a box-type structure can be classified into six groups according to the symmetry properties of the three panel pairs forming the box. In this paper, we demonstrate that such properties also reveal information about sound radiation effectiveness of each group of modes. The changes of radiation efficiencies and directivity patterns with the wavenumber ratio (the ratio between the acoustic and the plate bending wavenumbers) are examined for typical modes from each group. Similar characteristics of modal radiation efficiencies between a box structure and a corresponding simply supported panel are observed. The change of sound radiation patterns as a function of the wavenumber ratio is also illustrated. It is found that the sound radiation directivity of each box mode can be correlated to that of elementary sound sources (monopole, dipole, etc.) at frequencies well below the critical frequency of the plates of the box. The sound radiation pattern on the box surface also closely related to the vibration amplitude distribution of the box structure at frequencies above the critical frequency. In the medium frequency range, the radiated sound field is dominated by the edge vibration pattern of the box. The radiation efficiency of all box modes reaches a peak at frequencies above the critical frequency, and gradually approaches unity at higher frequencies.

  17. The Three-Dimensional Structural Basis of Type II Hyperprolinemia

    Energy Technology Data Exchange (ETDEWEB)

    Srivastava, Dhiraj; Singh, Ranjan K.; Moxley, Michael A.; Henzl, Michael T.; Becker, Donald F.; Tanner, John J. (UNL); (UMC)

    2012-08-31

    Type II hyperprolinemia is an autosomal recessive disorder caused by a deficiency in {Delta}{sup 1}-pyrroline-5-carboxylate dehydrogenase (P5CDH; also known as ALDH4A1), the aldehyde dehydrogenase that catalyzes the oxidation of glutamate semialdehyde to glutamate. Here, we report the first structure of human P5CDH (HsP5CDH) and investigate the impact of the hyperprolinemia-associated mutation of Ser352 to Leu on the structure and catalytic properties of the enzyme. The 2. 5-{angstrom}-resolution crystal structure of HsP5CDH was determined using experimental phasing. Structures of the mutant enzymes S352A (2.4 {angstrom}) and S352L (2.85 {angstrom}) were determined to elucidate the structural consequences of altering Ser352. Structures of the 93% identical mouse P5CDH complexed with sulfate ion (1.3 {angstrom} resolution), glutamate (1.5 {angstrom}), and NAD{sup +} (1.5 {angstrom}) were determined to obtain high-resolution views of the active site. Together, the structures show that Ser352 occupies a hydrophilic pocket and is connected via water-mediated hydrogen bonds to catalytic Cys348. Mutation of Ser352 to Leu is shown to abolish catalytic activity and eliminate NAD{sup +} binding. Analysis of the S352A mutant shows that these functional defects are caused by the introduction of the nonpolar Leu352 side chain rather than the removal of the Ser352 hydroxyl. The S352L structure shows that the mutation induces a dramatic 8-{angstrom} rearrangement of the catalytic loop. Because of this conformational change, Ser349 is not positioned to interact with the aldehyde substrate, conserved Glu447 is no longer poised to bind NAD{sup +}, and Cys348 faces the wrong direction for nucleophilic attack. These structural alterations render the enzyme inactive.

  18. Type II functional response for continuous, physiologically structured models.

    Science.gov (United States)

    Logan, J David; Ledder, Glenn; Wolesensky, William

    2009-07-21

    The goal of this work is to formulate a general Holling-type functional, or behavioral, response for continuous physiologically structured populations, where both the predator and the prey have physiological densities and certain rules apply to their interactions. The physiological variable can be, for example, a development stage, weight, age, or a characteristic length. The model leads to a Fredholm integral equation for the functional response, and, when inserted into population balance laws, it produces a coupled system of partial differential-integral equations for the two species, with a nonlocal integral term that arises from rules of interaction in the functional response. The general model is, typically, analytically intractable, but specialization to a structured prey-unstructured predator model leads to some analytic results that reveal interesting and unexpected dynamics caused by the presence of size-dependent handling times in the functional response. In this case, steady-states are shown to exist over long times, similar to the stable age-structure solutions for the McKendick-von Foerster model with exponential growth rates determined by the Euler-Lotka equation. But, for type II responses, there are early transient oscillations in the number of births that bifurcate in a few generations into either the decaying or growing steady-state. The bifurcation parameter is the initial level of prey. This special case is applied to a problem of the biological control of a structured pest population (e.g., aphids) by a predator (e.g., lady beetles). PMID:19362565

  19. Prediction of three social cognitive-motivational structure types.

    Science.gov (United States)

    Malerstein, A J; Ahern, M M; Pulos, S

    2001-10-01

    Previously, using interviews from Baumrind's longitudinal study, three cognitive-motivational structures (CMSs) were predicted in 68 adolescents from caregiving settings and from the CMS types of their mothers, based on the mothers' interviews elicited six years earlier. CMS theory proposes that during Piaget's Concrete Operational Period care-receiving influences the child's adoption of a social cognitive style, which corresponds to one of Piaget's stages of cognitive development. One who is classified as an Operational experiences the caregiving setting as tuned to the child's long-term interests, becomes focused on function and control of function and grasps the distinctions between and gradations of social attributes. One classified as future Intuitive experiences the caregiving as insufficient or unreliable and becomes focused on getting and having, and assesses social situations based on current striking dimensions. A person classified as being future Symbolic experiences the caregiving as out of tune with the self or the world, becomes focused on identity and emotional closeness, and may define self or object by a single attribute. This previous study did not distinguish between the influence of caregiving (including mothers' CMS) on the formation of adolescent CMS type and the possible constancy of CMS type from ages 9 to 15 years. The current study was designed to distinguish between these two possibilities, using data from 67 of the same mothers. Mothers' interviews were purged of descriptions of her child's behavior. Another interview was composed of the purged descriptions of child behavior. This was also done for interviews held when the child was 4 and 15 as well as at 9. From interviews with descriptions of child behavior purged, mother's CMS type at the child's age of 4 and 9 yr. agreed with her adolescent's previously assigned CMS type (p<.05), and caregiving setting at 9 years predicted the adolescent's CMS type (p<.05). From interviews composed of descriptions of only the child's behavior, adolescent CMS type agreed with previously assigned adolescent CMS type (p<.01). Findings were consonant with the idea that CMS type formation is influenced at about Age 9 and sufficiently established to be recognized at Age 15. PMID:11783566

  20. Structural characterization of thyroglobulin type-1 domains of equistatin

    OpenAIRE

    Galesa, K.; Pain, R.; Jongsma, M. A.; Turk, V.; Lenarci, B.

    2003-01-01

    Equistatin is a protein composed of three thyroglobulin type-1 domains. It inhibits papain-like cysteine proteinases and the aspartic proteinase, cathepsin D. To determine the structural basis for this inhibition we cloned and expressed the separated domains (eq d-1, eq d-2, eq d-3) in Pichia pastoris. Kinetic constants for the interaction of eq d-1 with papain and that of eq d-2 with cathepsin D are of similar order (subnanomolar) and are comparable to the constants obtained for full-length ...

  1. Crystal structure of wild-type human procathepsin K.

    OpenAIRE

    Sivaraman, J.; Lalumière, M; Ménard, R; Cygler, M

    1999-01-01

    Cathepsin K is a lysosomal cysteine protease belonging to the papain superfamily. It has been implicated as a major mediator of osteoclastic bone resorption. Wild-type human procathepsin K has been crystallized in a glycosylated and a deglycosylated form. The latter crystals diffract better, to 3.2 A resolution, and contain four molecules in the asymmetric unit. The structure was solved by molecular replacement and refined to an R-factor of 0.194. The N-terminal fragment of the proregion form...

  2. Novel intermetallics with the Ca11 Ga7 structure type

    International Nuclear Information System (INIS)

    The binary alkaline earth (AII) trielides Ca11 Ga7 and Sr11 In7 crystallize with a singular structure type (cubic, space group Fm3-bar m, a?1600 (AII=Ca) and 1700 (AII=Sr) pm, Z=8). Fourteen new ternary Ca and Sr mixed trielides and triel/tetrelides forming this structure type were synthesized from stoichiometric mixtures of the elements and characterized by single crystal X-ray diffraction. The structures exhibit isolated M(1) atoms (M(2)=Al, Ga, In, Sn, Pb) together with tetrahedral units [M(1)4], which are formed by the triel elements exclusively. Remarkably, one of the four crystallographically independent AII positions is - as in the pure element - coordinated by AII partners in a cuboctahedral arrangement. In the mixed MIII /MIV compounds, a maximum phase range up to a maximum composition limit of A11[M(1)4III][M(2)IV]3 is observed, which nearly corresponds to an ionic description according to the Zintl concept (tetrahedral anions [M4III]8- isoelectronic to white phosphorus P4 besides isolated noble gas isosteric tetrelide anions [MIV]4-). In the case of the Sr/In/Pb and some Ca compounds, the A position that is coordinated by alkaline earth atoms only is statistically substituted by the heavier triel/tetrel elestituted by the heavier triel/tetrel element. The stabilities and phase ranges of the compounds, which are influenced by geometric and electronic factors (investigated by FP-LAPW band structure calculations), are discussed

  3. The multicovering radius problem for some types of discrete structures

    CERN Document Server

    Aw, Alan J

    2011-01-01

    The covering radius problem, initially studied by coding theorists, investigates the maximum size of a collection of similar structures such that there exists another such structure that shares at most $k$ elements with each structure in the collection. In particular, Klapper in \\cite{klapper} describes an even more general problem in coding theory known as the multicovering radius problem in $\\mathbf F^n$, where $\\mathbf F$ is a field. At the same time, combinatorialists have been exploring the covering radius problem for discrete structures \\cite{quistorff}, e.g., collections of permutations (\\cite{keevash-ku}) and collections of perfect matchings (\\cite{aw-ku}). In this paper, we introduce a multicovering radius problem for both perfect matchings and permutations that is logically consistent with the one introduced in \\cite{klapper} but has not been studied hitherto; and provide some elementary and "frequency parameter" type results by means of generalizing the results obtained in \\cite{keevash-ku} and \\ci...

  4. The Importance of Disk Structure in Stalling Type I Migration

    CERN Document Server

    Kretke, Katherine A

    2012-01-01

    As planets form they tidally interact with their natal disks. Though the tidal perturbation induced by Earth and super-Earth mass planets is generally too weak to significantly modify the structure of the disk, the interaction is potentially strong enough to cause the planets to undergo rapid type I migration. This physical process may provide a source of short-period super-Earths, though it may also pose a challenge to the emergence and retention of cores on long-period orbits with sufficient mass to evolve into gas giants. Previous numerical simulations have shown that the type I migration rate sensitively depends upon the circumstellar disk's properties, particularly the temperature and surface density gradients. Here, we derive these structure parameters for 1) a self-consistent viscous-disk model based on a constant \\alpha-prescription, 2) an irradiated disk model that takes into account heating due to the absorption of stellar photons, and 3) a layered-accretion disk model with variable \\alpha-parameter...

  5. Dipole ordering, ionic conductivity, and cold nuclear fusion: Three types of cation mobility in the orthophosphates KTiOPO4 Na3M2(PO4)3 (M=Sc,Fe,Cr), NaTh2(PO4)3, KD2PO4, and related compounds

    International Nuclear Information System (INIS)

    As shown in earlier studies, crystals whose structures contain closely located positions statistically occupied by metal cations (split positions) may exhibit anomalies in physical properties, such as ferroelectric (FE) or antiferroelectric (AFE) ordering, superionic conduction (SIC), low thermal expansion coefficients, ultrarapid nuclear relaxation, etc. For example, splitting of Na positions lead to Fe ordering in low-temperature structures of Na3Sc2(PO4)3 and NaTh2(PO4)3 and to AFE ordering in Na3Zr2Si2PO12 (stoichiometric NASICON - one of the best three-dimensional superionic conductors). The coexistance of two types of split cation positions in KFeFPO4 was reported by Belokoeneva et al.; later, these splittings were shown to be accompanied by FE and AFE ordering. In this paper, the authors report an attempt to establish inter-relations between various physical phenomena related to cation mobility. They discuss three manifestations of cation mobility in orthophosphates with split cation positions: dipole ordering of both FE and AFE types, superionic conduction, and cold nuclear fusion (CNF)

  6. Structural trends in off stoichiometric chalcopyrite type compound semiconductors

    International Nuclear Information System (INIS)

    Energy supply is one of the most controversial topics that are currently discussed in our global community. Most of the energy delivered to the customer today has its origin in fossil and nuclear power plants. Indefinable risks and the radioactive waste repository problem of the latter as well as the global scarcity of fossil resources cause the renewable energies to grow more and more important for achieving sustainability. The main renewable energy sources are wind power, hydroelectric power and solar energy. On the photovoltaic (PV) market different materials are competing as part of different kinds of technologies, with the largest contribution still coming from wafer based crystalline silicon solar cells (95 %). Until now thin film solar cells only contribute a small portion to the whole PV market, but large capacities are under construction. Thin film photovoltaic shows a number of advantages in comparison to wafer based crystalline silicon PV. Among these material usage and production cost reduction are two prominent examples. The type of PV materials, which are analyzed in this work, are high potential compounds that are widely used as absorber layer in thin film solar cells. These are compound semiconductors of the type CuBIIICVI2 (BIII = In, Ga and CVI = Se, S). Several years of research have already gone into understanding the efficiency limiting factors for solar cell devices fabricated from this compound. Most of the studies concerning electronic defects are done by spectroscopic methods mostly performed using thin films from different kinds of synthesis, without any real knowledge regarding the structural origin of these defects. This work shows a systematic fundamental structural study of intrinsic point defects that are present within the material at various compositions in CuBIIICVI2 compound semiconductors. The study is done on reference powder samples with well determined chemical composition and using advanced diffraction techniques, such as neutron and synchrotron X-ray diffraction. The results show that the main existing defects are found to be copper vacancies and BIIICu anti-site defects. Type and concentrations vary with the composition. It is demonstrated that, when assuming spontaneous formation of electrically neutral defect complexes made of these isolated point defects, the density of cationic point defects is reduced by an order of magnitude. This explains why the existence of native cationic point defects may not be the main efficiency limiting factor in thin film solar cells built with a CuBIIICVI2 absorber. This pinpoints why the mere presence of native cationic point defects does probably not suffice as main efficiency limiting factor in thin film solar cells based on CuBIIICVI2-type absorbers.

  7. Gradient type optimization methods for electronic structure calculations

    CERN Document Server

    Zhang, Xin; Wen, Zaiwen; Zhou, Aihui

    2013-01-01

    The density functional theory (DFT) in electronic structure calculations can be formulated as either a nonlinear eigenvalue or direct minimization problem. The most widely used approach for solving the former is the so-called self-consistent field (SCF) iteration. A common observation is that the convergence of SCF is not clear theoretically while approaches with convergence guarantee for solving the latter are often not competitive to SCF numerically. In this paper, we study gradient type methods for solving the direct minimization problem by constructing new iterations along the gradient on the Stiefel manifold. Global convergence (i.e., convergence to a stationary point from any initial solution) as well as local convergence rate follows from the standard theory for optimization on manifold directly. A major computational advantage is that the computation of linear eigenvalue problems is no longer needed. The main costs of our approaches arise from the assembling of the total energy functional and its grad...

  8. Magnetic resonances in perovskite-type layer structures

    International Nuclear Information System (INIS)

    We have studied the q = 0 magnetic excitations of the perovskite-type layer structures A2MnCl4 with A = Rb, Csub(n)Hsub(2n+1)NH3 (n = 1,2,3), and NH3(CH2)sub(m)NH3MnCl4 (m = 2,4,5) in the antiferromagnetic and in the spin flop regime by means of magnetic resonance in the mm-wave range (30-130 GHz) and microwave range (9.2 GHz). The length of the organic molecules determines the separation of the MnCl6 octahedra. With increasing separation the Neel temperature and the antiferromagnetic resonance frequency decrease, which mainly originates from a decrease of the anisotropy field. (orig.)

  9. Maxwell-type behaviour from a geometrical structure

    International Nuclear Information System (INIS)

    We study which geometric structure can be constructed from the vierbein (frame/coframe) variables and which field models can be related to this geometry. The coframe field models, alternative to GR, are known as viable models for gravity, since they have the Schwarzschild solution. Since the local Lorentz invariance is violated, a physical interpretation of additional six degrees of freedom is required. The geometry of such models is usually given by two different connections-the Levi-Civita symmetric and metric-compatible connection and the Weitzenboeck flat connection. We construct a general family of linear connections of the same type, which includes two connections above as special limiting cases. We show that for dynamical propagation of six additional degrees of freedom it is necessary for the gauge field of infinitesimal transformations (antisymmetric tensor) to satisfy the system of two first-order differential equations. This system is similar to the vacuum Maxwell system and even coincides with it on a flat manifold. The corresponding 'Maxwell-compatible connections' are derived. Alternatively, we derive the same Maxwell-type system as a symmetry condition of the viable model Lagrangian. Consequently, we derive a nontrivial decomposition of the coframe field to the pure metric field plus a dynamical field of infinitesimal Lorentz rotations. An exact spherical-symmetric solution for our dynamical field is derived. It is bounded near the Schwarzschild radius. is bounded near the Schwarzschild radius. Further off, the solution is close to the Coulomb field

  10. Perovskite-type oxides - Oxygen electrocatalysis and bulk structure

    Science.gov (United States)

    Carbonio, R. E.; Fierro, C.; Tryk, D.; Scherson, D.; Yeager, E.

    1988-01-01

    Perovskite type oxides were considered for use as oxygen reduction and generation electrocatalysts in alkaline electrolytes. Perovskite stability and electrocatalytic activity are studied along with possible relationships of the latter with the bulk solid state properties. A series of compounds of the type LaFe(x)Ni1(-x)O3 was used as a model system to gain information on the possible relationships between surface catalytic activity and bulk structure. Hydrogen peroxide decomposition rate constants were measured for these compounds. Ex situ Mossbauer effect spectroscopy (MES), and magnetic susceptibility measurements were used to study the solid state properties. X ray photoelectron spectroscopy (XPS) was used to examine the surface. MES has indicated the presence of a paramagnetic to magnetically ordered phase transition for values of x between 0.4 and 0.5. A correlation was found between the values of the MES isomer shift and the catalytic activity for peroxide decomposition. Thus, the catalytic activity can be correlated to the d-electron density for the transition metal cations.

  11. Structure of the type IX group B Streptococcus capsular polysaccharide and its evolutionary relationship with types V and VII.

    Science.gov (United States)

    Berti, Francesco; Campisi, Edmondo; Toniolo, Chiara; Morelli, Laura; Crotti, Stefano; Rosini, Roberto; Romano, Maria Rosaria; Pinto, Vittoria; Brogioni, Barbara; Torricelli, Giulia; Janulczyk, Robert; Grandi, Guido; Margarit, Immaculada

    2014-08-22

    The Group B Streptococcus capsular polysaccharide type IX was isolated and purified, and the structure of its repeating unit was determined. Type IX capsule ? 4)[NeupNAc-?-(2 ? 3)-Galp-?-(1 ? 4)-GlcpNAc-?-(1 ? 6)]-?-GlcpNAc-(1 ? 4)-?-Galp-(1 ? 4)-?-Glcp-(1 ? appears most similar to types VII and V, although it contains two GlcpNAc residues. Genetic analysis identified differences in cpsM, cpsO, and cpsI gene sequences as responsible for the differentiation between the three capsular polysaccharide types, leading us to hypothesize that type V emerged from a recombination event in a type IX background. PMID:24990951

  12. Type IIA orientifolds on SU(2)-structure manifolds

    Energy Technology Data Exchange (ETDEWEB)

    Danckaert, Thomas

    2010-11-15

    We investigate the possible supersymmetry-preserving orientifold projections of type IIA string theory on a six-dimensional background with SU(2)-structure. We find two categories of projections which preserve half of the low-energy supersymmetry, reducing the effective theory from an N=4 supergravity theory, to an N=2 supergravity. For these two cases, we impose the projection on the low-energy spectrum and reduce the effective N=4 supergravity action accordingly. We can identify the resulting gauged N=2 supergravity theory and bring the action into canonical form. We compute the scalar moduli spaces and characterize the gauged symmetries in terms of the geometry of these moduli spaces. Due to their origin in N=4 supergravity, which is a highly constrained theory, the moduli spaces are of a very simple form. We find that, for suitable background manifolds, isometries in all scalar sectors can become gauged. The obtained gaugings share many features with those of N=2 supergravities obtained previously from other G-structure compactifications. (orig.)

  13. Altered nuclear structure in myotonic dystrophy type 1-derived fibroblasts.

    Science.gov (United States)

    Rodríguez, R; Hernández-Hernández, O; Magaña, J J; González-Ramírez, R; García-López, E S; Cisneros, B

    2015-02-01

    Myotonic dystrophy type 1 (DM1) is a multisystem genetic disorder caused by a triplet nucleotide repeat expansion in the 3' untranslated region of the Dystrophia Myotonica-Protein Kinase (DMPK) gene. DMPK gene transcripts containing CUG expanded repeats accumulate in nuclear foci and ultimately cause altered splicing/gene expression of numerous secondary genes. The study of primary cell cultures derived from patients with DM1 has allowed the identification and further characterization of molecular mechanisms underlying the pathology in the natural context of the disease. In this study we show for the first time impaired nuclear structure in fibroblasts of DM1 patients. DM1-derived fibroblasts exhibited altered localization of the nuclear envelope (NE) proteins emerin and lamins A/C and B1 with concomitant increased size and altered shape of nuclei. Abnormal NE organization is more common in DM1 fibroblasts containing abundant nuclear foci, implying expression of the expanded RNA as determinant of nuclear defects. That transient expression of the DMPK 3' UTR containing 960 CTG but not with the 3' UTR lacking CTG repeats is sufficient to generate NE disruption in normal fibroblasts confirms the direct impact of mutant RNA on NE architecture. We also evidence nucleoli distortion in DM1 fibroblasts by immunostaining of the nucleolar protein fibrillarin, implying a broader effect of the mutant RNA on nuclear structure. In summary, these findings reveal that NE disruption, a hallmark of laminopathy disorders, is a novel characteristic of DM1. PMID:25307018

  14. Magnetic Structure of Rapidly Rotating FK Comae-Type Coronae

    CERN Document Server

    Cohen, O; Kashyap, V L; Korhonen, H; Elstner, D; Gombosi, T I

    2010-01-01

    We present a three-dimensional simulation of the corona of an FK Com-type rapidly rotating G giant using a magnetohydrodynamic model that was originally developed for the solar corona in order to capture the more realistic, non-potential coronal structure. We drive the simulation with surface maps for the radial magnetic field obtained from a stellar dynamo model of the FK Com system. This enables us to obtain the coronal structure for different field topologies representing different periods of time. We find that the corona of such an FK Com-like star, including the large scale coronal loops, is dominated by a strong toroidal component of the magnetic field. This is a result of part of the field being dragged by the radial outflow, while the other part remains attached to the rapidly rotating stellar surface. This tangling of the magnetic field,in addition to a reduction in the radial flow component, leads to a flattening of the gas density profile with distance in the inner part of the corona. The three-dim...

  15. Types of tectonic structures favourable for metamorphogenetic uranium deposit formation

    International Nuclear Information System (INIS)

    Structures controlling the location of uranium metamorphogenetic deposits are identified: regional structures, determining the location of ore zones and ore areas; structures of ore fields; structures of ore deposits; structures of ore masses; intraore structures. All the structures arose before ore deposition and they served as ways of solution penetration, resulting in preore metasomatic alterations. Along them tectonic replacements were renewed, accompanied by infiltration of ore-bearing solutions and ore deposition. Methods for the study of metamorphogenetic deposit structures are enumerated

  16. Deformations of complex structures on Riemann surfaces and integrable structures in Whitham type hierarchies

    CERN Document Server

    Odesskii, Alexander

    2015-01-01

    We obtain variational formulas for holomorphic objects on Riemann surfaces with respect to arbitrary local coordinates on moduli space of complex structures. These formulas are written in terms of a canonical object on moduli space which corresponds to the pairing between the space of quadratic differentials and the tangent space to moduli space. This canonical object satisfies certain commutation relations which appear to be the same as ones emerged in integrability theory of Whitham type hierarchies. Driven by this observation, we develop the theory of Whitham type hierarchies integrable by hydrodynamic reductions as a theory of certain differential-geometric objects.

  17. The influence of the type of road, the type of vehicle and the age structure on the road transport emission

    Directory of Open Access Journals (Sweden)

    Aleksandra KUTRZYK

    2010-01-01

    Full Text Available The total emission level is heavily dependent on the number of vehicles. Additionally, the type of vehicles and their age structures are very important. The structure of vehicles also depends on the type of the road. The article presents the results of calculations of the pollutants emission from the road transport. Total emission was calculated with combination of the investigation results i.e. the type of vehicles and their age structures for different types of roads. The investigations have been made for different classes of roads with different types of vehicles. The traffic line has been recorded in the same length of time. On the basis of analysis of the recorded traffic line, the number and the type of vehicles have been estimated. The classification of vehicles have been made according to the level of emission i.e. passenger cars, light duty vehicles, heavy duty vehicles, busses and others, taking into consideration the age structures of vehicles. The level of total traffic emission has been calculated on the basis of results. There has been used the Copert programme methodology. The results of the calculations have been made with combination of the type of road, the speed of vehicles, the type of vehicles and their age structure, are presented.

  18. Structural trends in off stoichiometric chalcopyrite type compound semiconductors

    Energy Technology Data Exchange (ETDEWEB)

    Stephan, Christiane

    2011-03-15

    Energy supply is one of the most controversial topics that are currently discussed in our global community. Most of the energy delivered to the customer today has its origin in fossil and nuclear power plants. Indefinable risks and the radioactive waste repository problem of the latter as well as the global scarcity of fossil resources cause the renewable energies to grow more and more important for achieving sustainability. The main renewable energy sources are wind power, hydroelectric power and solar energy. On the photovoltaic (PV) market different materials are competing as part of different kinds of technologies, with the largest contribution still coming from wafer based crystalline silicon solar cells (95 %). Until now thin film solar cells only contribute a small portion to the whole PV market, but large capacities are under construction. Thin film photovoltaic shows a number of advantages in comparison to wafer based crystalline silicon PV. Among these material usage and production cost reduction are two prominent examples. The type of PV materials, which are analyzed in this work, are high potential compounds that are widely used as absorber layer in thin film solar cells. These are compound semiconductors of the type CuB{sup III}C{sup VI}{sub 2} (B{sup III} = In, Ga and C{sup VI} = Se, S). Several years of research have already gone into understanding the efficiency limiting factors for solar cell devices fabricated from this compound. Most of the studies concerning electronic defects are done by spectroscopic methods mostly performed using thin films from different kinds of synthesis, without any real knowledge regarding the structural origin of these defects. This work shows a systematic fundamental structural study of intrinsic point defects that are present within the material at various compositions in CuB{sup III}C{sup VI}{sub 2} compound semiconductors. The study is done on reference powder samples with well determined chemical composition and using advanced diffraction techniques, such as neutron and synchrotron X-ray diffraction. The results show that the main existing defects are found to be copper vacancies and B{sup III}{sub Cu} anti-site defects. Type and concentrations vary with the composition. It is demonstrated that, when assuming spontaneous formation of electrically neutral defect complexes made of these isolated point defects, the density of cationic point defects is reduced by an order of magnitude. This explains why the existence of native cationic point defects may not be the main efficiency limiting factor in thin film solar cells built with a CuB{sup III}C{sup VI}{sub 2} absorber. This pinpoints why the mere presence of native cationic point defects does probably not suffice as main efficiency limiting factor in thin film solar cells based on CuB{sup III}C{sup VI}{sub 2}-type absorbers.

  19. Molecular structure of human galactokinase: implications for type II galactosemia.

    Science.gov (United States)

    Thoden, James B; Timson, David J; Reece, Richard J; Holden, Hazel M

    2005-03-11

    Galactokinase functions in the Leloir pathway for galactose metabolism by catalyzing the MgATP-dependent phosphorylation of the C-1 hydroxyl group of alpha-D-galactose. The enzyme is known to belong to the GHMP superfamily of small molecule kinases and has attracted significant research attention for well over 40 years. Approximately 20 mutations have now been identified in human galactokinase, which result in the diseased state referred to as Type II galactosemia. Here we report the three-dimensional architecture of human galactokinase with bound alpha-D-galactose and Mg-AMPPNP. The overall fold of the molecule can be described in terms of two domains with the active site wedged between them. The N-terminal domain is dominated by a six-stranded mixed beta-sheet whereas the C-terminal motif contains six alpha-helices and two layers of anti-parallel beta-sheet. Those residues specifically involved in sugar binding include Arg37, Glu43, His44, Asp46, Gly183, Asp186, and Tyr236. The C-1 hydroxyl group of alpha-D-galactose sits within 3.3 A of the gamma-phosphorus of the nucleotide and 3.4 A of the guanidinium group of Arg37. The carboxylate side chain of Asp186 lies within approximately 3.2 A of the C-2 hydroxyl group of alpha-D-galactose and the guanidinium group of Arg37. Both Arg37 and Asp186 are strictly conserved among both prokaryotic and eukaryotic galactokinases. In addition to providing molecular insight into the active site geometry of the enzyme, the model also provides a structural framework upon which to more fully understand the consequences of the those mutations known to give rise to Type II galactosemia. PMID:15590630

  20. New types of nonlinear optical materials - Li3VO4- and Li3PO4-type structures

    Science.gov (United States)

    Sakata, Shin'ichi; Fujii, Itsuhiro

    1991-08-01

    Li3VO4 and LI3PO4 types of structure crystals are found as new types of nonlinear optical materials for second-harmonic generation. Their lattices are formed of only the MO4 oxygen tetrahedra, being different from other typical nonlinear optical materials that have been developed previously.

  1. Seismic verification methods for structures and equipment of VVER-type and RBMK-type NPPs (summary of experiences)

    International Nuclear Information System (INIS)

    The main verification methods for structures and equipment of already existing VVER-type and RBMK-type NPPs are briefly described. The following aspects are discussed: fundamental seismic safety assessment principles for VVER/RBMK-type NPPs (seismic safety assessment procedure, typical work plan for seismic safety assessment of existing NPPs, SMA (HCLPF) calculations, modified GIP (GIP-VVER) procedure, similarity of VVER/RBMK equipment to that included in the SQUG databases and seismic interactions

  2. Seismic verification methods for structures and equipment of VVER-type and RBMK-type NPPs (summary of experiences)

    International Nuclear Information System (INIS)

    The main verification methods for structures and equipment of already existing VVER-type and RBMK-type NPPs are briefly described. In this connection the following aspects are discussed: fundamental seismic safety assessment principles for VVER/RBMK-type NPPs (seismic safety assessment procedure, typical work plan for seismic safety assessment of existing NPPs, SMA (HCLPF) calculations, modified GIP (GIP-VVER) procedure, similarity of VVER/RBMK equipment to that included in the SQUG databases and seismic interactions. (author)

  3. The prolongation structure of the inhomogeneous equation of the reaction-diffusion type

    International Nuclear Information System (INIS)

    The inhomogeneous extension of equations of the reaction-diffusion type is investigated by means of the covariant prolongation structures theory. We construct the sl(2, R) x R(?(t)) prolongation structure for an inhomogeneous equation of the reaction-diffusion type and give the corresponding AKNS-type equations and the Baecklund transformation

  4. Fine structure analysis of type-specific and type-common antigenic sites of herpes simplex virus glycoprotein D.

    OpenAIRE

    Dietzschold, B.; Eisenberg, R. J.; Ponce Leon, M.; Golub, E.; Hudecz, F.; Varrichio, A.; Cohen, G. H.

    1984-01-01

    The fine structure of the antigenic determinants of herpes simplex virus type 1 and 2 glycoprotein D (gD) was analyzed to determine whether structural differences underlie the differential immunogenicity of these glycoproteins. A region common to herpes simplex virus type 1 and 2 gD (amino acid residues 11 to 19) and two sites specific for herpes simplex virus type 2 gD (one determined by proline at position 7, the other determined by asparagine at position 21) were localized within the N-ter...

  5. Quadrant-type X-band single-cell structure for high gradient tests

    International Nuclear Information System (INIS)

    We are building a new high-gradient X-band (11.424 GHz) testbench, called “Shield-B,” for basic studies to establish a acceleration technology with 100MV/m or higher, where various single-cell structures are to be tested. We focus on quadrant-type structures, on which no surface currents associated with magnetic fields flow across cell-to-cell junctions unlike disk-type structures. In this study, we propose a quadrant-type X-band single-cell structure with a heavy damped structure by waveguides, overcoming its issues. (author)

  6. Synthesis and crystal structure of CuZrTiO5-A new crystal structure type

    International Nuclear Information System (INIS)

    A new compound, CuZrTiO5, was synthesized as strongly pleochroic green crystals from the oxides between 995 and 1010 deg. C, 1 atm. Its crystal structure was determined by single crystal XRD, resulting in R (F2>2?(F2))=0.032 and wR (all data)=0.079). CuZrTiO5 is orthorhombic, space group P212121, a=3.5871(3) A, b=6.6968(4) A, c=14.6679(9) A, V=352.35(4) A3, Z=4. The structure is topologically similar to In2TiO5 but differs in space group and cation coordination. CuZrTiO5 has relatively regular TiO6 polyhedra, but coordination is 7+1 for Zr, and 4+2 for Cu due to the Jahn-Teller effect. Ordering of the long Cu-O bonds causes reduction in symmetry relative to In2TiO5. Layers of Cu alternate with Ti+Zr on (001), giving rise to a distinct cleavage. Bond valence sums on Ti and Zr are far from ideal, which appears due to the limited ability of this structural topology to avoid close next-nearest neighbour distances. - Graphical abstract: The new compound CuZrTiO5 is orthorhombic (P212121), with a=3.5871(3) A, b=6.6968(4) A, c=14.6679(9) A. The structure, determined with single crystal XRD, represents a new crystal structure type that is a slight distortion of that of In2TiO5 but differs in space group and cation coordination.dination.

  7. Phase transition between the CaCl2-type and ?-PbO2-type structures of germanium dioxide

    International Nuclear Information System (INIS)

    Observations of the phase transition between the CaCl2-type (Pnnm) and ?-PbO2-type (Pbcn) structures of germanium dioxide (GeO2) were carried out using quench and in situ x-ray diffraction methods in a laser-heated diamond anvil cell (LHDAC). First-principle theoretical simulations were also performed to complement the experimental results. The experiments showed that the transition had a positive dP/dT dependence. The phase boundary between the CaCl2-type and ?-PbO2-type structures in the temperature range 1500-2400 K was determined to be P (GPa)=(53±3)+(0.011±0.005)(T-1800) (K) based on the equation of state of platinum and the ruby scale. The positive slope of the transition is consistent with the known phase boundary between the CaCl2-type and ?-PbO2-type structures of tin dioxide (SnO2) as germanium dioxide analog and theoretical simulation results. However, our results do not agree with the slope of the phase boundary of silica (SiO2), which has been reported to have a negative slope

  8. Cage structure materials for n-type transparent conducting oxides

    Science.gov (United States)

    Bertoni, Mariana Ines

    The transport properties of mayenite-based materials, Ca12Al 14O33, were investigated. Systems studied included H-doped/UV-irradiated Ca12Al14O33, Ca(12- x)MgxAl14O 33 (x = 0.1, 0.3, 0.5, 0.8, 1) and Ca12Al(14- x)Six O33+x2 (x = 1, 2, 3, 4). The as-prepared Ca12Al14O 33 exhibited a room temperature electronic conductivity on the order of 10-10 S/cm, and a high temperature (600°C) ionic conductivity approximately an order of magnitude less than that of yttria-stabilized zirconia. After H-doping/UV-irradiation Ca12Al14O33 displayed an electronic conductivity of 0.3 S/cm at room temperature rising reversibly to 1 S/cm at ˜130°. Beyond this temperature hydrogen loss is evident and with it the carrier concentration decreases. Below room temperature the system exhibits a variable range hopping and a small polaron hopping above room temperature. H-treated/UV-irradiated Mg-substituted compounds present inferior electrical properties compared to Ca12Al14O 33, with conductivities in the range of 0.15-0.28 S/cm at room temperature. Magnesium is suggested to be responsible for the overall decrease in conductivity, as theoretical calculations suggest that it acts as a blocking agent. On the other hand, the proton-implanted/UV-irradiated Ca12Al(14-x)Si x O33+x2 shows an increase in conductivity, consistent with the aliovalent substitution. Conductivities of 0.68 S/cm were found for the higher Si-substitution level (in H-implanted specimens) suggesting that the amount of free oxygen ions inside the structural cavities plays a significant role in determining the electrical properties of the compound. Results are in good agreement with density functional calculations performed on all these systems. The highly reduced [Ca24Al28O62] +4+4e- system presents a wide range of conductivities dependent on the reduction time. The maximum value obtained was 1400 S/cm for Ca12Al14O33 reduced in the presence of titanium shot for 4 days of treatment. A reversal in the sign of the thermopower was observed for the high conductivity samples. The temperature dependance of the conductivity shows degenerate behavior above room temperature, and a linear relation between the resistivity and temperature below room temperature. This degenerate behavior suggests an insulator-to-metal conversion, however, it can also be explained by the small polaron mechanism observed for the H-treated/UV-activated mayenite-based samples. Ultimately, mobility data will define the type of mechanism governing this compound's behavior.

  9. Crystalline structure of magnets in Ticonal-type alloy

    International Nuclear Information System (INIS)

    Methods of X-ray diffraction analysis and X-ray diffraction topography are used to study crystal structure of alloy YuNDK35T5AA magnets. Lattice parameters are determined for ?- and ?'-phases which particle form a pseudomonocrystal. It is revealed that the magnets have pencil- or plate-like structure and developed substructure, the latter gives rise to scattering of a given [100] orientation and to macroscopic bending of a (100) plane. It is shown that the magnets contain different volume contents of additional parasitic crystallites. The data on the actual structure of the magnets are correlated with induction values in an air gap

  10. Filamentary structures of the cosmic web and the nonlinear Schroedinger type equation

    Energy Technology Data Exchange (ETDEWEB)

    Tigrak, E; Weygaert, R van de; Jones, B J T, E-mail: tigraks@astro.rug.nl [Kapteyn Astron. Inst., University of Groningen, PO Box 800, 9700 AV Groningen (Netherlands)

    2011-02-01

    We show that the filamentary type structures of the cosmic web can be modeled as solitonic waves by solving the reaction diffusion system which is the hydrodynamical analogous of the nonlinear Schroedinger type equation. We find the analytical solution of this system by applying the Hirota direct method which produces the dissipative soliton solutions to formulate the dynamical evolution of the nonlinear structure formation.

  11. Subband structure comparison between n- and p- type double delta-doped Ga As quantum wells

    International Nuclear Information System (INIS)

    We compute the electron level structure (n-type) and the hole subband structure (p-type) of double -doped GaAs (DDD) quantum wells, considering exchange effects. The Thomas-Fermi (TF), and Thomas-Fermi-Dirac (TFD) approximations have been applied in order to describe the bending of the conduction and valence band, respectively. The electron and the hole subband structure study indicates that exchange effects are more important in p-type DDD quantum wells than in n-type DDD Also our results agree with the experimental data available. (Author) 33 refs., 2 tabs., 5 figs

  12. Bi-Hamiltonian structures of Toda type systems

    OpenAIRE

    Evripidou, Charalampos A.

    2015-01-01

    In this paper we define a family of systems which have similarities with the Toda lattice. We construct two Lax pair representations and the associate Poisson structures for these systems. These systems lie between the classical Toda lattice and the full Kostant-Toda lattice. A Hamiltonian and a bi-Hamiltonian structure for these systems is constructed and also master symmetries for some low dimensional cases are presented.

  13. Soil/structure interactions of eastern US type earthquakes

    International Nuclear Information System (INIS)

    This paper presents analyses and conclusions pertaining to the earthquake motions felt at Virgil C. Summer, Perry and Krsko nuclear power plants. Consideration is given to promote an improved understanding of these events, describe common characteristics, assess damage potential, and recommend operating procedures for similar future events. An easy-to-follow analytical investigation is performed to describe how the earthquakes recorded at Krsko may be influenced by soil/structure interaction including a few parametric studies to account for uncertainties in the soil properties. These consist of variations in the shear and compressional wave velocities and variations in the seismic wave environment in the form of arbitrarily oriented body waves or Rayleigh waves. The analysis takes into account nonlinearity of the soil material, radiation and hysteretic damping, ground-water table level, structural embedment, and structure/structure interaction. The analysis is based on state-of-the-art computer software, elaborate analysis techniques and simpler engineering approximations. Results of analysis show clear evidence of soil/structure interaction, nonlinear softening of the soil material and encouraging qualitative and quantitative agreement with the recorded measurements. The structural response motions display high rocking mode

  14. Crystal structure of zebrafish Interferons 1 and 2 reveals a conservation of type I Interferon structure in vertebrates

    DEFF Research Database (Denmark)

    Hamming, Ole Jensen; Lutfalla, Georges

    2011-01-01

    Interferons (IFNs) play a major role in orchestrating the innate immune response towards viruses in vertebrates, and their defining characteristic is their ability to induce an antiviral state in responsive cells. Interferons have been described in a multitude of species, from bony fish to mammals. However, our current knowledge about the molecular function of fish IFNs as well as their evolutionary relationship to tetrapod IFNs is limited. Here we establish the 3D structure of zebrafish IFN1 and IFN2 by crystallography. These high-resolution structures offer the first structural insight into fish cytokines. Tetrapods possess two types of IFNs which play an immediate antiviral role: type I IFNs (e.g. IFN-? and IFN-?) and type III IFNs (IFN-?), and each type is characterized by its specific receptor usage. Similarly, two groups of antiviral IFNs with distinct receptors exist in fish, including zebrafish. IFN1 and IFN2 represent group I and group II, respectively. Nevertheless, both structures reported here reveal a characteristic type I IFN architecture with a straight F helix, as opposed to the remaining class II cytokines including IFN-?, where helix F contains a characteristic bend. Phylogenetic trees derived from structure-guided multiple alignments confirmed that both groups of fish IFNs are evolutionarily closer to type I than to type III tetrapod IFNs. Thus, these fish IFNs belong to the type I IFN family. Our results also imply that a dual antiviral IFN system has arisen twice during vertebrate evolution.

  15. Structures of the Mating-Type Loci of Cordyceps takaomontana

    OpenAIRE

    Yokoyama, Eiji; Yamagishi, Kenzo; Hara, Akira

    2003-01-01

    Nucleotide sequences of the mating-type loci MAT1-1 and MAT1-2 of Cordyceps takaomontana were determined, which is the first such report for the clavicipitaceous fungi. MAT1-1 contains two mating-type genes, MAT1-1-1 and MAT1-1-2, but MAT1-1-3 could not be found. On the other hand, MAT1-2 has MAT1-2-1. A pseudogene of MAT1-1-1 is located next to MAT1-2.

  16. Atlas of fine structures of dynamic spectra of solar type IV-dm and some type II radio bursts

    International Nuclear Information System (INIS)

    The author presents an atlas of spectral fine structures of solar radio bursts of types IV and II around 1 m wavelength, as obtained with a multichannel spectrograph at Dwingeloo. The structures form largely a collection of observations of these events during late 1968 through 1974, thus covering almost entirely the declining branch of solar cycle 20. The spectrograph has an extra enhanced contrast output with properties quite different from those of the commonly used swept frequency spectrographs. The corresponding instrumental characteristics and effects are discussed. A classification of fine structures and an analysis of their statistical properties and of those of the pertinent radio events are also given. (Auth.)

  17. The on axis coupled structure type RF gun

    CERN Document Server

    Oda, F; Nakayama, A; Tanabe, E

    1999-01-01

    The fundamental design of this newly developed RF gun with a thermionic cathode is the pi/2 mode standing wave structure. It has two accelerating cells and a coupling cell located on the beam axis, a so-called on axis coupled structure (OCS). This structure offers a stable operation for high beam current, owing to high group velocity and wide bandwidth. It is important to reduce damage onto the cathode caused by back bombardment, especially for long macropulse operation, such as in an FEL injector. Back bombardment, as well as output beam profile was simulated by using the electromagnetic field analytical codes 'EMSYS'(2D) and 'MAFIA'(3D). The cavity shape was optimized to reduce back bombardment power without sacrificing beam emittance.

  18. Structural, electronic and optical properties of fluorite-type compounds

    Science.gov (United States)

    Khenata, R.; Daoudi, B.; Sahnoun, M.; Baltache, H.; Rérat, M.; Reshak, A. H.; Bouhafs, B.; Abid, H.; Driz, M.

    2005-09-01

    A theoretical study of structural, elastic, electronic and optical properties of CaF2, SrF2 and BaF2 is presented, using the full-potential linearized augmented plane-wave (FPLAPW) method as implemented in the Wien97 code. In this approach the generalized gradient approximation (GGA) was used for the exchange-correlation (XC) potential. Results are given for lattice constant, bulk modulus, its pressure derivative and elastic constants. Band structure, density of states, pressure coefficients of energy gaps and refractive indices are also given. The results are compared with previous calculations and experimental data.

  19. Structures in the fundamental plane of early-type galaxies

    CERN Document Server

    Fraix-Burnet, Didier; Chattopadhyay, Tanuka; Chattopadhyay, Asis Kumar; Davoust, Emmanuel

    2010-01-01

    The fundamental plane of early-type galaxies is a rather tight three-parameter correlation discovered more than twenty years ago. It has resisted a both global and precise physical interpretation despite a consequent number of works, observational, theoretical or using numerical simulations. It appears that its precise properties depend on the population of galaxies in study. Instead of selecting a priori these populations, we propose to objectively construct homologous populations from multivariate analyses. We have undertaken multivariate cluster and cladistic analyses of a sample of 56 low-redshift galaxy clusters containing 699 early-type galaxies, using four parameters: effective radius, velocity dispersion, surface brightness averaged over effective radius, and Mg2 index. All our analyses are consistent with seven groups that define separate regions on the global fundamental plane, not across its thickness. In fact, each group shows its own fundamental plane, which is more loosely defined for less diver...

  20. Priestley-type dualities for partially ordered structures

    CERN Document Server

    Caramello, Olivia

    2012-01-01

    We introduce a general framework for generating dualities between categories of partial orders and categories of ordered Stone spaces; we recover in particular the classical Priestley duality for distributive lattices and establish several other dualities for different kinds of partially ordered structures.

  1. Optical processes in different types of photonic band gap structures

    Science.gov (United States)

    Wang, Zhiguo; Gao, Mengqin; Ullah, Zakir; Chen, Haixia; Zhang, Dan; Zhang, Yiqi; Zhang, Yanpeng

    2015-06-01

    For the first time, we investigate the photonic band gap (PBG) structure in the static and moving electromagnetically induced grating (EIG) through scanning the frequency detunings of the probe field, dressing field and coupling field. Especially, the suppression and enhancement of the four wave mixing band gap signal (FWM BGS) and the probe transmission signal (PTS) can be observed when we scan the dressing field frequency detuning in the FWM BGS system. It is worth noting that the PBG structure and FWM BGS appear at the right of the electromagnetically induced transparency (EIT) position in the case of scanning the frequency detuning of the coupling field in the FWM BGS system, while the PBG structure and FWM BGS appears at the left of the EIT position on the condition of scanning the probe field frequency detuning. Moreover, in the moving PBG structure, we can obtain the nonreciprocity of FWM BGS. Furthermore, we can modulate the intensity, width, location of the FWM BGS and PTS through changing the frequency detunings and intensities of the probe field, dressing field and coupling field, sample length and the frequency difference of coupling fields in EIG. Such scheme could have potential applications in optical diodes, amplifiers and quantum information processing.

  2. Types of personality motivation structure of women who are acquiring higher education in psychology

    Directory of Open Access Journals (Sweden)

    TETIANA PARTYKO

    2013-09-01

    Full Text Available The article deals with the results of empirical research on the types of personality motivation structure of women who are acquiring higher education in psychology. Two types have been singled out: expressive and impulsive. The expressive type comprises two components: ideal motivation aimed at life necessities, general activity and social utility, and real motivation aimed at comfort, social status and communication. In the structure of the impulsive type there are three components: real motivation aimed at life necessities, social status, general activity and social utility; real motivation aimed at communication and comfort; creativity motivation aimed at self-development and creative activity. Women belonging to the expressive type of personality motivation structure have more positive self-attitude and a higher level of psychological well-being than women belonging to the impulsive type.

  3. Structure of a dimeric fungal ?-type carbonic anhydrase

    DEFF Research Database (Denmark)

    Cuesta-Seijo, Jose Antonio; Borchert, Martin Simon

    2011-01-01

    The crystal structure of Aspergillus oryzae carbonic anhydrase (AoCA) was determined at 2.7Å resolution and it revealed a dimer, which only has precedents in the ? class in two membrane and cancer-associated enzymes. ? carbonic anhydrases are underrepresented in fungi compared to the ? class, this being the first structural representative. The overall fold and zinc binding site resemble other well studied carbonic anhydrases. A major difference is that the histidine, thought to be the major proton shuttle residue in most mammalian enzymes, is replaced by a phenylalanine in AoCA. This finding poses intriguing questions as to the biological functions of fungal ? carbonic anhydrases, which are promising candidates for biotechnological applications.

  4. Hidden E type structures in dilute A models

    OpenAIRE

    Suzuki, J.

    1999-01-01

    The hidden E_{7} (E_{6}) structure has been conjectured for the minimal model ${\\cal M}_{4,5} ({\\cal M}_{6,7}$) perturbed by $\\Phi_{1,2}$ in the context of conformal field theory(CFT). Motivated by this, we examine the dilute A_{4, 6} models, which are expected to be corresponding lattice models. Thermodynamics of the equivalent one dimensional quantum systems is analyzed via the quantum transfer matrix approach. Appropriate auxiliary functions, related to kinks in the theor...

  5. Structural studies of different types of ferroelectric liquid crystalline substances.

    Czech Academy of Sciences Publication Activity Database

    Obadovi?, D.Ž.; Stojanovi?, M.; Bubnov, Alexej; Éber, N.; Cvetinov, M.; Vajda, A.

    2011-01-01

    Ro?. 35, ?. 1 (2011), s. 3-13. ISSN 1450-7404 R&D Projects: GA AV ?R IAA100100911; GA AV ?R(CZ) GA202/09/0047; GA ?R(CZ) GAP204/11/0723 Grant ostatní: RFASI(RU) 02.740.11.5166 Institutional research plan: CEZ:AV0Z10100520 Keywords : ferroelectric liquid crystals * phase transition * structure of liquid crystalline phases * molecular parameters Subject RIV: BM - Solid Matter Physics ; Magnetism

  6. Type of disturbance and ecological history determine structural stability

    OpenAIRE

    van der Wurff, A. W. G.; Kools, S.A.E.; Boivin, M. E. Y.; Brink, P.J., van den; Megen, H.H.B., van; Riksen, J.A.G.; Doroszuk, A.; Kammenga, J.E.

    2007-01-01

    This study aims to reveal whether complexity, namely, community and trophic structure, of chronically stressed soil systems is at increased risk or remains stable when confronted with a subsequent disturbance. Therefore, we focused on a grassland with a history of four centuries of patchy contamination. Nematodes were used as model organisms because they are an abundant and trophically diverse group and representative of the soil food web and ecosystem complexity. In a field survey, a relatio...

  7. Structural Constraints on Human Immunodeficiency Virus Type 1 Nef Function

    OpenAIRE

    Raney, Alexa; Shaw, Alice Y.; Foster, John L; Garcia, J. Victor

    2007-01-01

    HIV-1 Nef is a multifunctional protein that exerts its activities through interactions with multiple cellular partners. Nef uses different domains and mechanisms to exert its functions including cell surface down-modulation of CD4 and MHC-I receptors and activation of the serine/threonine kinase PAK-2. We inserted tags at the C-terminus and proximal to the N-terminus of Nef and the effects on Nef’s structure/function relationships were examined. We discovered significant defects in MHC-I do...

  8. Structural study of the type II 3-dehydroquinate dehydratase from Actinobacillus pleuropneumoniae

    OpenAIRE

    Maes, D.; Gonza?lez-rami?rez, L. A.; Lo?pez-jaramillo, F. J.; Yu, B.; Bondt, H.; Zegers, I.; Afonina, E.; Garci?a Ruiz, Juan Manuel; Gulnik, S.

    2004-01-01

    The structure of the type II dehydroquinate dehydratase (DHQase) from Actinobacillus pleuropneumoniae, the third enzyme of the shikimate pathway, has been determined. Crystals diffracting to 1.7 Å were obtained in space and on earth using the counter-diffusion technique. The structure was solved using molecular replacement and refined to high resolution. The overall structure of the dodecameric enzyme is described and compared with structures of DHQases from other bacteria. DHQases contain a...

  9. Structural constraints on human immunodeficiency virus type 1 Nef function

    International Nuclear Information System (INIS)

    HIV-1 Nef is a multifunctional protein that exerts its activities through interactions with multiple cellular partners. Nef uses different domains and mechanisms to exert its functions including cell surface down-modulation of CD4 and MHC-I receptors and activation of the serine/threonine kinase PAK-2. We inserted tags at the C-terminus and proximal to the N-terminus of Nef and the effects on Nef's structure/function relationships were examined. We discovered significant defects in MHC-I down-modulation with the insertion of HA/FLAG tags at either region. We also found impaired PAK-2 activation with a C-terminal fusion with GFP. Interestingly, Nef-GFP and Nef-GH7 induced MHC-I down-modulation, suggesting that the negative charge of the HA/FLAG tag could contribute to the observed defect. Together, these observations highlight elements of Nef's functional complexity and demonstrate previously unsuspected structural requirements for PAK-2 activation and MHC-1 down-modulation in Nef's flexible N- and C-terminal regions

  10. Ferroelectric and ferroelastic domains in bronze type tunnel structures

    International Nuclear Information System (INIS)

    This brief review serves to illustrate the capabilities of high-resolution electron microscopy (HREM) to reveal fine structures of a surprising variety of microstructural domains. Example include the hierarchy of chaotic states existing in the incommensurate room temperature phase of strontium barium niobate. HREM showed directly nature of the atoms (W,Nb) displacements responsible for the hexagonal component of the superstructures occurring throughout phase transitions of potassium niobium tungstate (PNT). The reciprocal lattice geometry of the commensurate superlattice phase of barium sodium niobate has been determined and a full structural model derived; thus the space group appears to be Im2a with orthorhombic cell parameters a=35.18Aangstroem, b=35.24Aangstroem, c=7.99 Aangstroem. Non-stoichiometric phases of PNT have orthorhombic superstructures and the microdiffraction analysis allowed possible orthorhombic space groups and unit cell parameters to be derived for the three phases. It is suggested that PNT may be considered as an alternative subject for non-linear laser technology. 20 figs., 9 figs

  11. On defining structured geometry types in PostgreSQL to implement a spatial database

    Science.gov (United States)

    Huang, Qian; Gao, Yong; Wu, Xi

    2009-10-01

    PostgreSQL is a widely used open source object-relational database system, on which the PostGIS spatial database is built. By defining geometry types in PostgreSQL according to the OGC WKB standard, geographic features are usually defined as a base type which is stored as general binary data blocks without internal structures. But the unstructured representation of the structured geometry data model brings the problem of inefficient data access. In this paper, we propose a new approach that uses an array of structured composite types to replace the unstructured base types to store geometry types. Then PostgreSQL 8.3 is extended to support spatial data management in this proposed approach following the standard of OGC's Simple Feature Specification. A contrastive experiment proves the advantages and efficiency of this method.

  12. Strontium oxoalkoxotitanates: a new structural type of pentanuclear alkoxides

    International Nuclear Information System (INIS)

    Bimetallic oxo complex Sr6Ti4O4(OPr-iso)20 (I) crystallizes from solutions of Sr(OPr-iso)2 and Ti(OPr-iso)4 in isopropyl alcohol or in iso-PrOH-toluene mixture at Sr:Ti ranging from 2:1 to 1:2. Given an excess of Ti(OPr-iso)4 (Sr:Ti = 1:4), SrTi4O2(OPr-iso)14(iso-PrOH)2 (II) is formed. The structures of I and II have been determined by X-ray diffraction. The molecule of I contains a Sr6 octahedron and four ?3-OR and four ?4-O groups alternate at its faces; the latter are involved in trigonal bipyramid [(?4-O)Ti(?-OR)3(OR)]. The molecule of II is formed by two vertex (Sr)-sharing [SrTi2] triangles and each triangle is centered by a ?3-O atom. The [Ti2(?3-O)(?-OR)2(OR)5] groups contain two nonequivalent Ti atoms with a distorted trigonal-bipyramidal coordination; one of the atoms shares an edge with Sr atom [(?3-O)(?-OR)], and the other Ti atom shares a ?3-O vertex with Sr atom and it is linked by RO...HOR H-bond with alcohol molecule solvating the Sr atom. In both complexes strontium has octahedral coordination

  13. KY3F10 structural type and compounds similar to it in structure with chemical bonds of different nature

    International Nuclear Information System (INIS)

    Consideration is given to a series of complexes structures of intermetallic compounds and relative carbides and nitrides, among which the cases of complete coincidence with the structure of typically ionic KY3F10 compound occur. Similarity of KYF10, Cr23C6, Tb5Rh6Sn18 structural types was established. It is shown that atomic motive, typical for KY3F10, is present in Ag36Te22Tl7 structure and is formed by Fe and Tl atoms. Atomic motive of Bi4Cu4Mn3 structure was interpreted as derivative of KY3F10 motive, and two submotives, close to the motive of KY3F10 structure, were distinguished in Cr21La6N23 structure

  14. Selection versus Structure: Explaining Family Type Differences in Contact with Close Kin

    Science.gov (United States)

    De Bruycker, Trees

    2008-01-01

    This article focuses on one aspect of family networks, namely, the frequency of contact with close kin for adults living in different traditional and new family types. Two mechanisms are hypothesized to account for the differences. The first focuses on structural factors such as the number and type of persons in the primary family network,…

  15. Experimental investigation on sandwich structure ring-type ultrasonic motor.

    Science.gov (United States)

    Peng, Taijiang; Shi, Hongyan; Liang, Xiong; Luo, Feng; Wu, Xiaoyu

    2015-02-01

    This paper presents a manufacture method for a sandwich structure Ultrasonic Motor (USM) and experiment. Two pieces of rotor clamped on a stator, and a stainless steel disk-spring is bonded on the hollow rotor disk to provide the press by a nut assembled on the shaft. The stator is made of a double-side Printed-Circuit Board (PCB) which is sawed out the ring in the center and connected on the board with three legs. On each side of the ring surface, there are electrodes connected at the same position via through hole. The three layer drive circuit for sine, cosine, and ground signal is connected on the board through each leg. There are many piezoelectric components (PZT) bonded between two electrodes and fill soldering tin on each electrode. Then PZT is welded on PCB by reflow soldering. Finally, rub the gibbous soldering tin down to the position of PZT surface makes sure the surface contacts with rotor evenly. The welding process can also be completed by Surface Mounted Technology (SMT). A prototype motor is manufactured by this method. Two B03 model shapes of the stator are obtained by the finite element analysis and the optimal frequency of the motor is 56.375 kHz measured by impedance instrument. The theoretical analysis is conducted for the relationship between the revolving speed of the USM and thickness of stator ring, number of the travelling waves, PZT amplitude, frequency and the other parameters. The experiment result shows that the maximum revolving speed is 116 RPM and the maximum torque is 25 N mm, when the actuate voltage is 200 VAC. PMID:25213313

  16. Structure of human POFUT2: insights into thrombospondin type 1 repeat fold and O-fucosylation

    OpenAIRE

    Chen, Chun-I; Keusch, Jeremy J.; Klein, Dominique; Hess, Daniel; Hofsteenge, Jan,; Gut, Heinz

    2012-01-01

    This study presents the first crystal structure of human O-fucosyltransferase 2 bound to its substrate, the thrombospondin type I repeat present in numerous proteins. Functional analysis provides insight into the catalytic mechanism generating this post-translational modification and structure encoded substrate specificity.

  17. Response of Dome-enclosed Box-type Structure to Underwater Explosion

    Directory of Open Access Journals (Sweden)

    O.R. Nandagopan

    2013-07-01

    Full Text Available In the development of underwater sensor systems, the sensor arrays are configured for different shapes like cylindrical, rectangular and spherical depending on the requirement. The rectangular shaped box–type structure discussed here has both top and bottom ends open. Flanges stiffen the top and bottom ends, and gussets are used to connect the flanges with the structure. In this paper, the box-type structure is subjected to non-contact underwater explosion in a shock tank to study the peak free field pressure on the structure. To simulate the actual conditions, the structure is placed in free flooded area and covered with a dome. The free-field peak pressure on the dome and structure are plotted with time. The measured pressure curves are in agreement with the empirical predictions reported in literature. It is concluded that around 85 per cent of the shock impulse acting on the dome is transmitted to the box-type structure. The dome and box-type structure withstood the explosive load, thereby validating their design.

  18. Response of Dome-enclosed Box-type Structure to Underwater Explosion

    Directory of Open Access Journals (Sweden)

    O. R. Nandagopan

    2013-07-01

    Full Text Available In the development of underwater sensor systems, the sensor arrays are configured for different shapes like cylindrical, rectangular and spherical depending on the requirement. The rectangular shaped box–type structure discussed here has both top and bottom ends open. Flanges stiffen the top and bottom ends, and gussets are used to connect the flanges with the structure. In this paper, the box-type structure is subjected to non-contact underwater explosion in a shock tank to study the peak free field pressure on the structure. To simulate the actual conditions, the structure is placed in free flooded area and covered with a dome. The free-field peak pressure on the dome and structure are plotted with time. The measured pressure curves are in agreement with the empirical predictions reported in literature. It is concluded that around 85 per cent of the shock impulse acting on the dome is transmitted to the box-type structure. The dome and box-type structure withstood the explosive load, thereby validating their design.Defence Science Journal, 2013, 63(4, pp.381-385, DOI:http://dx.doi.org/10.14429/dsj.63.2130

  19. Structure refinement of decagonal Al-Ni-Co, superstructure type I

    OpenAIRE

    Kuczera, Pawel; Wolny, Janusz; Fleischer, Frank; Steurer, Walter

    2010-01-01

    Abstract The structure of decagonal Al-Ni-Co, superstructure type I (so called Edagawa phase) was refined in the physical space. A statistical approach was used to calculate the structure factor based on the rhombic Penrose This tiling, with tile edge length 12.1 Å, as reference frame. A total number of 691 parameters was refined against 6843 structure amplitudes, merged in Laue group 10/m.

  20. Of the crystal chemistry of Ruddlesden-Porter type structures in high Tc ceramic superconductors

    International Nuclear Information System (INIS)

    This paper reports on atomistic computer simulation employed to examine the energetics and crystal chemistry of some Ruddlesden-Popper type oxide superconductors. Similar structural patterns have been noticed in the superconducting oxides. The formation of Ruddlesden-Popper type layers (alternating slabs of rocksalt and perovskite structures) is similar in many respects to that seen in the system Sr-Ti-O. However, there are some significant differences, for example, the rocksalt and perovskite blocks in the new superconducting compounds are not necessarily electrically neutral unlike in the Sr-Ti-O system and this may well lead to significant differences in their structural chemistry

  1. Subaortic (Type 6 Muscular Band—Innocent Bystander or Pathologic Structure?

    Directory of Open Access Journals (Sweden)

    J Ker

    2010-08-01

    Full Text Available Intraventricular tendons are structures that was identified more than a hundred years ago. It has been suggested that they represent intracavitary radiations of the bundle of His and that they may be an isolated finding or be associated with structural cardiac abnormalities. Loukas et al divided these structures into five categories and recently a sixth type have been added. Various physiological disturbances have been observed due to the sixth type of tendon, such as ST segment elevation and right bundle branch block. It has been noted that this peculiar structure appears too thick to be called a tendon, thus the term band. This retrospective analysis analyzed the incidence of the thick, subaortic (type 6 muscular band in a cardiovascular clinic.

  2. Development, characteristics and comparative structural analysis of tensegrity type cable domes

    Directory of Open Access Journals (Sweden)

    Nenadovi? Aleksandra

    2010-01-01

    Full Text Available Tensegrity type cable domes are three-dimensional structural configurations, prestressed inside the perimeter compression ring, in which the continuous tension throughout the roof structure is made by continuous tension cables and discontinuous compression struts. These kinds of structures can be formed like spatially triangulated networks or like networks nontriangulated in space. This paper examines some effects of network geometry on the behaviour and structural efficiency of tensegrity type cable domes. In this paper the roof cover is considered non-interactive with the supporting structure, unlike rigidly clad tensegrity type cable domes. Since the main bearing elements of tensegrity type cable domes are prestressed cables, they show non-linear load deformation and rely upon geometric stiffness. A geometrically non-linear analysis of non-triangulated and triangulated structures for different load conditions was conducted employing a computer program based on the perturbation theory. The incrementally-iterative procedure, with an approximation of the stiffness matrix by combining the elastic and geometric stiffness matrix, allows detection of structural instabilities.

  3. Spectroscopic Evidence for an Oxazolone Structure in Anionic b-Type Peptide Fragments

    Science.gov (United States)

    Grzetic, Josipa; Oomens, Jos

    2012-02-01

    Infrared spectra of anionic b-type fragments generated by collision induced dissociation (CID) from deprotonated peptides are reported. Spectra of the b2 fragments of deprotonated AlaAlaAla and AlaTyrAla have been recorded over the 800-1800 cm-1 spectral range by multiple-photon dissociation (MPD) spectroscopy using an FTICR mass spectrometer in combination with the free electron laser FELIX. Structural characterization of the b-type fragments is accomplished by comparison with density functional theory calculated spectra at the B3LYP/6-31++G(d,p) level for different isomeric structures. Although diketopiperazine structures represent the energetically lowest isomers, the IR spectra suggest an oxazolone structure for the b2 fragments of both peptides. Deprotonation is shown to occur on the oxazolone ?-carbon, which leads to a conjugated structure in which the negative charge is practically delocalized over the entire oxazolone ring, providing enhanced gas-phase stability.

  4. The Types of Argument Structure Used by Hillary Clinton in the CNN Democratic Presidential Debate

    Directory of Open Access Journals (Sweden)

    Anggie Angeline

    2009-01-01

    Full Text Available This qualitative research was conducted to examine the types of argument structure by Hillary Clinton in part one of the CNN Democratic Presidential Debate since Hillary, who had a great deal of experiences in political parties, was supposed to be able to construct convincing arguments that had good argument structures. The theories used to analyze were Bierman and Assali’s (1996, King’s (n.d. and Stanlick’s (2003. The findings showed that there were five types of argument structure used: serial, linked, convergent, divergent, and hybrid argument structures. The linked argument structure was the argument structure used the most frequently in Hillary’s utterances in the debate, while the divergent was the least one. Thus, it could be concluded that Hillary’s speech in the Presidential Debate was quite interesting since she could combine all the five types of argument structure, though the frequency of using them was not the same and it seems that linked argument structure was the most effective strategy for her in arguing about the politic, economy, and social issues.

  5. In Situ D-periodic Molecular Structure of Type II Collagen

    Energy Technology Data Exchange (ETDEWEB)

    Antipova, Olga; Orgel, Joseph P.R.O. (IIT)

    2010-05-06

    Collagens are essential components of extracellular matrices in multicellular animals. Fibrillar type II collagen is the most prominent component of articular cartilage and other cartilage-like tissues such as notochord. Its in situ macromolecular and packing structures have not been fully characterized, but an understanding of these attributes may help reveal mechanisms of tissue assembly and degradation (as in osteo- and rheumatoid arthritis). In some tissues such as lamprey notochord, the collagen fibrillar organization is naturally crystalline and may be studied by x-ray diffraction. We used diffraction data from native and derivative notochord tissue samples to solve the axial, D-periodic structure of type II collagen via multiple isomorphous replacement. The electron density maps and heavy atom data revealed the conformation of the nonhelical telopeptides and the overall D-periodic structure of collagen type II in native tissues, data that were further supported by structure prediction and transmission electron microscopy. These results help to explain the observed differences in collagen type I and type II fibrillar architecture and indicate the collagen type II cross-link organization, which is crucial for fibrillogenesis. Transmission electron microscopy data show the close relationship between lamprey and mammalian collagen fibrils, even though the respective larger scale tissue architecture differs.

  6. Structural and biochemical analyses of regio- and stereospecificities observed in a type II polyketide ketoreductase.

    Science.gov (United States)

    Javidpour, Pouya; Korman, Tyler Paz; Shakya, Gaurav; Tsai, Shiou-Chuan

    2011-05-31

    Type II polyketides include antibiotics such as tetracycline and chemotherapeutics such as daunorubicin. Type II polyketides are biosynthesized by the type II polyketide synthase (PKS) that consists of 5-10 stand-alone domains. In many type II PKSs, the type II ketoreductase (KR) specifically reduces the C9-carbonyl group. How the type II KR achieves such a high regiospecificity and the nature of stereospecificity are not well understood. Sequence alignment of KRs led to a hypothesis that a well-conserved 94-XGG-96 motif may be involved in controlling the stereochemistry. The stereospecificity of single-, double-, and triple-mutant combinations of P94L, G95D, and G96D were analyzed in vitro and in vivo for the actinorhodin KR (actKR). The P94L mutation is sufficient to change the stereospecificity of actKR. Binary and ternary crystal structures of both wild-type and P94L actKR were determined. Together with assay results, docking simulations, and cocrystal structures, a model for stereochemical control is presented herein that elucidates how type II polyketides are introduced into the substrate pocket such that the C9-carbonyl can be reduced with high regio- and stereospecificities. The molecular features of actKR important for regio- and stereospecificities can potentially be applied in biosynthesizing new polyketides via protein engineering that rationally controls polyketide keto reduction. PMID:21506596

  7. Likelihood Ratio Type Test and its Critical Values for Structural Change of Unknown Changepoint

    Directory of Open Access Journals (Sweden)

    Gazi Mahabubul Alam

    2013-01-01

    Full Text Available This study considers the problem of testing for a structural change of unknown timing in a regression coefficient in the linear regression model. This is a non-standard testing problem and practical important situation facing applied modelers. Simulation methods were used to generate a range of exact critical values of the Likelihood Ratio (LR type test for different sample sizes, numbers of regressors and types of regressors. We found that the critical values depend on sample size, the number of regressors and to a less extend on the type of explanatory variables. We recommend using the LR type test statistic for testing structural change of unknown timing with our critical value.

  8. Likelihood Ratio Type Test and its Critical Values for Structural Change of Unknown Changepoint

    OpenAIRE

    Gazi Mahabubul Alam; Mahbuba Yeasmin; Mohammad Nurul Azam

    2013-01-01

    This study considers the problem of testing for a structural change of unknown timing in a regression coefficient in the linear regression model. This is a non-standard testing problem and practical important situation facing applied modelers. Simulation methods were used to generate a range of exact critical values of the Likelihood Ratio (LR) type test for different sample sizes, numbers of regressors and types of regressors. We found that the critical values depend on sample size, the numb...

  9. Spectroscopic Evidence for an Oxazolone Structure in Anionic b-Type Peptide Fragments

    OpenAIRE

    Grzetic, J.; Oomens, J.

    2011-01-01

    Infrared spectra of anionic b-type fragments generated by collision induced dissociation (CID) from deprotonated peptides are reported. Spectra of the b2 fragments of deprotonated AlaAlaAla and AlaTyrAla have been recorded over the 800–1800 cm–1 spectral range by multiple-photon dissociation (MPD) spectroscopy using an FTICR mass spectrometer in combination with the free electron laser FELIX. Structural characterization of the b-type fragments is accomplished by comparison with density fu...

  10. The two types of 3-dehydroquinase have distinct structures but catalyze the same overall reaction

    OpenAIRE

    Gourley, David G.; Shrive, Annette K.; Polikarpov, Igor; Krell, Tino; Coggins, John R.; Hawkins, Alastair R.; Isaacs, Neil W.; Sawyer, Lindsay

    1999-01-01

    The structures of enzymes catalyzing the reactions in central metabolic pathways are generally well conserved as are their catalytic mechanisms. The two types of 3-dehydroquinate dehydratase (DHQase) are therefore most unusual since they are unrelated at the sequence level and they utilize completely different mechanisms to catalyze the same overall reaction. The type I enzymes catalyze a cis-dehydration of 3-dehydroquinate via a covalent imine intermediate, while the typ...

  11. Structural Characterization of Lignin in Wild-type versus COMT Down-regulated Switchgrass

    OpenAIRE

    ArthurRagauskas; YunqiaoPu; ChunxiangFu

    2014-01-01

    This study examined the chemical structural characteristics of cellulolytic enzyme lignin isolated from switchgrass focusing on comparisons between wild-type control and caffeic acid 3-O-methyltransferase (COMT) down-regulated transgenic line. Nuclear magnetic resonance (NMR) techniques including 13C, 31P, and two-dimensional 13C-1H heteronuclear single quantum coherence (HSQC) as well as gel permeation chromatography (GPC) were employed. Compared to the wild-type, the COMT down-regulated tra...

  12. Variance of the Boundary Layer Structure in Dependence of distinct Circulation Types

    Science.gov (United States)

    Philipp, Andreas; Beck, Christoph; Jacobeit, Jucundus

    2015-04-01

    Variability of local climate features is related on the one hand to large scale circulation patterns, but is modified additionally by regional or local influences. This is true for basic climate variables like temperature and precipitation but also for more complex environmental conditions like air quality, e.g. PM10 concentration. Regional and local influences are to a large extend represented by the atmosperic boundary structure, i.e. the height of the mixed layer or its stability determining fluxes of temperature and impulse as well as water vapor etc. The presented study focusses on the interaction between the boundary layer structure and large scale circulation types for selected radiosonde stations. Crculation is described by a k-means cluster analysis of European circulation fields, retrieved from the NCEP/NCAR reanalysis. The boundary layer structure is derived from European radiosonde data collected in the Integrated Global Radiosonde Archive (IGRA). Here the mixed layer heigth and stability indices are anaylsed for within-type variance in a first step for different circulation types created independently from any other information. In a second step circulation types are created including boundary layer information. Both kinds of types are then realted to local impact variables in order to achieve conclusions about the interdependence of both, the large scale circulation and the boundary layer structure in modifying local climate variables.

  13. Variations of Structural Components: Specific Intercultural Differences in Facial Morphology, Skin Type, and Structures

    OpenAIRE

    Mcknight, Aisha; Momoh, Adeyiza O.; Bullocks, Jamal M.

    2009-01-01

    Analysis of the differences in facial morphology and skin structure and tone among ethnic groups within the realm of plastic surgery is relevant due to the increasing number of ethnic individuals seeking cosmetic surgery. Previous classifications of ideal facial morphologic characteristics have been revised and challenged over the years to accurately reflect the differences in facial structure that are aesthetically pleasing to individuals of differing ethnic groups. The traditional neoclassi...

  14. High-pressure structural investigation of several zircon-type orthovanadates

    OpenAIRE

    Errandonea, D.; Lacomba-Perales, R.; Ruiz-Fuertes, J.; SEGURA, A.; Achary, S.N.; Tyagi, A.K.

    2009-01-01

    Room temperature angle-dispersive x-ray diffraction measurements on zircon-type EuVO4, LuVO4, and ScVO4 were performed up to 27 GPa. In the three compounds we found evidence of a pressure-induced structural phase transformation from zircon to a scheelite-type structure. The onset of the transition is near 8 GPa, but the transition is sluggish and the low- and high-pressure phases coexist in a pressure range of about 10 GPa. In EuVO4 and LuVO4 a second transition to a M-fergu...

  15. Great Barrier Reef butterflyfish community structure: the role of shelf position and benthic community type

    Science.gov (United States)

    Emslie, M. J.; Pratchett, M. S.; Cheal, A. J.; Osborne, K.

    2010-09-01

    The extent to which fish communities are structured by spatial variability in coral reef habitats versus stochastic processes (such as larval supply) is very important in predicting responses to sustained and ongoing habitat degradation. In this study, butterflyfish and benthic communities were surveyed annually over 15 years on 47 reefs (spanning 12° of latitude) of the Great Barrier Reef (GBR). Spatial autocorrelation in the structure of butterflyfish communities versus key differences in reef habitats was investigated to assess the extent to which the structure of these fish communities is influenced by habitat conditions. Benthic communities on each of the 47 reefs were broadly categorised as either: 1. Poritidae/Alcyoniidae, 2. mixed taxa, 3. soft coral or 4. Acropora-dominated habitats. These habitat types most reflected increases in water clarity and wave exposure, moving across the GBR shelf from coastal to outer-shelf environments. In turn, each habitat type also supported very distinct butterflyfish communities. Hard coral feeders were always the dominant butterflyfish species in each community type. However, the numerically dominant species changed according to habitat type, representing spatial replacement of species across the shelf. This study reveals clear and consistent differences in the structure of fish communities among reefs associated with marked differences in habitat structure.

  16. High-pressure U3O8 with the fluorite-type structure

    International Nuclear Information System (INIS)

    A new high-pressure phase of U3O8, which has a fluorite-type structure, forms at pressures greater than ?8.1 GPa that was confirmed by in situ x-ray diffraction (XRD) measurements. The fluorite-type U3O8 is stable at pressures at least up to ?40 GPa and temperatures to 1700 K, and quenchable to ambient conditions. Based on the XRD analysis, there is a huge volume collapse (>20%) for U3O8 during the phase transition and the quenched high-pressure phase is 28% denser than the initial orthorhombic phase at ambient conditions. The high-pressure phase has a very low compressibility comparing with the starting orthorhombic phase. - Graphical abstract: ?-U3O8 is in a layered structure with orthorhombic symmetry, at high pressures, it transformed to a fluorite-type cubic structure. There are a lot of defects in the cubic structure, and it is a new kind of hyperstoichiometric uranium oxide, which is stable at ambient conditions. - Highlights: • A new fluorite-type high-pressure phase was found in hyperstoichometric UO2+x (x?0.8). • The new high-pressure structure is quenchable to ambient conditions. • Pressure driven phase transition in orthorhombic U3O8 was first found

  17. Novel Compact Mushroom-Type EBG Structure for Electromagnetic Coupling Reduction of Microstrip Antenna array

    Science.gov (United States)

    Hu, Lizhong; Wang, Guangming; Liang, Jiangang; Zhang, Chenxin

    2015-03-01

    A novel compact electromagnetic bandgap (EBG) structure consisting of two turns complementary spiral resonator (CSR) and conventional mushroom EBG (CM-EBG) structure is introduced to suppress the mutual coupling in antenna arrays for multiple-input and multiple-output (MIMO) applications. Eigenmode calculation is used to investigate the proposed CSR-loaded mushroom-type EBG (MT-EBG), which proved to exhibit bandgap property and a miniaturization of 48.9% is realized compared with the CM-EBG. By inserting the proposed EBG structure between two E-plane coupled microstrip antennas, a mutual coupling reduction of 8.13 dB has been achieved numerically and experimentally. Moreover, the EBG-loaded antenna has better far-field radiation patterns compared with the reference antenna. Thus, this novel EBG structure with advantages of compactness and high decoupling efficiency opens an avenue to new types of antennas with super performances.

  18. Structure of an essential type IV pilus biogenesis protein provides insights into pilus and type II secretion systems.

    Science.gov (United States)

    Yamagata, Atsushi; Milgotina, Ekaterina; Scanlon, Karen; Craig, Lisa; Tainer, John A; Donnenberg, Michael S

    2012-05-25

    Type IV pili (T4Ps) are long cell surface filaments, essential for microcolony formation, tissue adherence, motility, transformation, and virulence by human pathogens. The enteropathogenic Escherichia coli bundle-forming pilus is a prototypic T4P assembled and powered by BfpD, a conserved GspE secretion superfamily ATPase held by inner-membrane proteins BfpC and BfpE, a GspF-family membrane protein. Although the T4P assembly machinery shares similarity with type II secretion (T2S) systems, the structural biochemistry of the T4P machine has been obscure. Here, we report the crystal structure of the two-domain BfpC cytoplasmic region (N-BfpC), responsible for binding to ATPase BfpD and membrane protein BfpE. The N-BfpC structure reveals a prominent central cleft between two ?/?-domains. Despite negligible sequence similarity, N-BfpC resembles PilM, a cytoplasmic T4P biogenesis protein. Yet surprisingly, N-BfpC has far greater structural similarity to T2S component EpsL, with which it also shares virtually no sequence identity. The C-terminus of the cytoplasmic domain, which leads to the transmembrane segment not present in the crystal structure, exits N-BfpC at a positively charged surface that most likely interacts with the inner membrane, positioning its central cleft for interactions with other Bfp components. Point mutations in surface-exposed N-BfpC residues predicted to be critical for interactions among BfpC, BfpE, and BfpD disrupt pilus biogenesis without precluding interactions with BfpE and BfpD and without affecting BfpD ATPase activity. These results illuminate the relationships between T4P biogenesis and T2S systems, imply that subtle changes in component residue interactions can have profound effects on function and pathogenesis, and suggest that T4P systems may be disrupted by inhibitors that do not preclude component assembly. PMID:22387466

  19. Insights into the Mechanism of Type I Dehydroquinate Dehydratases from Structures of Reaction Intermediates*

    OpenAIRE

    Light, Samuel H.; Minasov, George; Shuvalova, Ludmilla; Duban, Mark-eugene; Caffrey, Michael; Anderson, Wayne F.; Lavie, Arnon

    2010-01-01

    The biosynthetic shikimate pathway consists of seven enzymes that catalyze sequential reactions to generate chorismate, a critical branch point in the synthesis of the aromatic amino acids. The third enzyme in the pathway, dehydroquinate dehydratase (DHQD), catalyzes the dehydration of 3-dehydroquinate to 3-dehydroshikimate. We present three crystal structures of the type I DHQD from the intestinal pathogens Clostridium difficile and Salmonella enterica. Structures of the enzyme with substrat...

  20. Crystal structure of a type II dehydroquinate dehydratase-like protein from Bifidobacterium longum

    OpenAIRE

    Light, Samuel H.; Krishna, Sankar N.; Bergan, Raymond C.; Lavie, Arnon; Anderson, Wayne F.

    2013-01-01

    Dehydroquinate dehydratase (DHQD) catalyzes the third step in the biosynthetic shikimate pathway. Here we identify a Bifidobacterium longum protein with high sequence homology to type II DHQDs but no detectable DHQD activity under standard assay conditions. A crystal structure reveals that the B. longum protein adopts a DHQD-like tertiary structure but a distinct quaternary state. Apparently forming a dimer, the B. longum protein lacks the active site aspartic acid contributed from a neighbor...

  1. Croatian banking sector research: relationship between ownership structure, concentration, owners’ type and bank performance

    OpenAIRE

    Igor Tomi?i?; Ana ?ori?; Marina Kla?mer ?alopa

    2012-01-01

    Banks are important financial intermediaries of any national economy, and corporate governance has an important role in banking sector; especially due to processes of the globalization and the internationalization, and also because of the sensitivity of the activities between the interest groups. The objective of this paper is to examine the relationship between ownership structure, concentration, owners’ type and bank performance. The authors made a research of banks' ownership structure u...

  2. Comparative structural analysis of glycoprotein gD of herpes simplex virus types 1 and 2.

    OpenAIRE

    Eisenberg, R. J.; Ponce Leon, M.; Cohen, G. H.

    1980-01-01

    We studied the synthesis and processing of the type-common glycoprotein gD in herpes simplex virus type 2 (HSV-2) and compared it structurally to glycoprotein gD of herpes simplex virus type 1 (HSV-1). We demonstrated that in HSV-2, gD undergoes posttranslational processing from a lower-molecular-weight precursor (pgD51) to a higher-molecular-weight product (gD56). Tryptic peptide analysis by cation-exchange chromatography indicated that this processing step altered neither the methionine nor...

  3. Parallel conduction in p-type gallium nitride homo-structures

    International Nuclear Information System (INIS)

    Usually the multi-layer technique is applied for the growth of p-type gallium nitride (GaN) films, and the active p-type layer is deposited on an n-type GaN buffer layer. In the present paper, the electrical transport phenomena (conductivity and Hall effect) have been studied in p-GaN/GaN homo-structures grown on a sapphire substrate. Two types of GaN buffer layers were used: a silicon-doped one and another strongly compensated by magnesium. We demonstrate that in the analysis of the electrical conduction phenomena the parallel conduction in the n-type buffer layer cannot be neglected, and it manifests itself in the studies of a conduction process as a function of temperature and as a function of electric field intensity

  4. Crystal structures and magnetic properties of iron (III)-based phosphates: Na{sub 4}NiFe(PO{sub 4}){sub 3} and Na{sub 2}Ni{sub 2}Fe(PO{sub 4}){sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Essehli, Rachid, E-mail: rachid_essehli@yahoo.fr [Laboratory of Mineral Solid and Analytical Chemistry ' LCSMA' , Department of Chemistry, Faculty of Sciences, University Mohamed I, Po. Box 717, 60000 Oujda (Morocco); Bali, Brahim El [Laboratory of Mineral Solid and Analytical Chemistry ' LCSMA' , Department of Chemistry, Faculty of Sciences, University Mohamed I, Po. Box 717, 60000 Oujda (Morocco); Benmokhtar, Said [LCMS, Laboratoire de Chimie des Materiaux Solides, Departement de chimie, Faculte des Sciences Ben M' SIK, Casablanca (Morocco); Bouziane, Khalid [Physics Department, College of Science, Sultan Qaboos University, PO Box 36, Postal Code 123 Al Khod, Sultanate of Oman (Oman); Manoun, Bouchaib [Laboratoire de Physico-Chimie des Materiaux, Departement de Chimie, FST Errachidia, University Moulay Ismail, B.P. 509 Boutalamine, Errachidia (Morocco); Abdalslam, Mouner Ahmed [Materials Science, Technical University Darmstadt, Darmstadt (Germany); Ehrenberg, Helmut [IFW Dresden, Helmholtzstr. 20, D-01069 Dresden (Germany)

    2011-01-28

    Graphical abstract: A perspective view of the Na{sub 2}Ni{sub 2}Fe(PO{sub 4}){sub 3} structure along the [0 0 1] direction. Both compounds seem to exibit antiferromagnetic interactions between magnetic entities at low temperature. Display Omitted Research highlights: > Nasicon and Alluaudite compounds, Iron(III)-based phosphates, Crystal structures of Na{sub 4}NiFe(PO{sub 4}){sub 3} and Na{sub 2}Ni{sub 2}Fe(PO{sub 4}){sub 3}. > Magnetism behaviours of Na{sub 4}NiFe(PO{sub 4}){sub 3} and Na{sub 2}Ni{sub 2}Fe(PO{sub 4}){sub 3}. > Antiferromagnetism interactions. > Mossbauer spectroscopy. - Abstract: Crystal structures from two new phosphates Na{sub 4}NiFe(PO{sub 4}){sub 3} (I) and Na{sub 2}Ni{sub 2}Fe(PO{sub 4}){sub 3} (II) have been determined by single crystal X-ray diffraction analysis. Compound (I) crystallizes in a rhombohedral system (S. G: R-3c, Z = 6, a = 8.7350(9) A, c = 21.643(4) A, R{sub 1} = 0.041, wR{sub 2}=0.120). Compound (II) crystallizes in a monoclinic system (S. G: C2/c, Z = 4, a = 11.729(7) A, b = 12.433(5) A, c = 6.431(2) A, {beta} = 113.66(4){sup o}, R{sub 1} = 0.043, wR{sub 2}=0.111). The three-dimensional structure of (I) is closely related to the Nasicon structural type, consisting of corner sharing [(Ni/Fe)O{sub 6}] octahedra and [PO{sub 4}] tetrahedra forming [NiFe(PO{sub 4}){sub 3}]{sup 4+} units which align in chains along the c-axis. The Na{sup +} cations fill up trigonal antiprismatic sites within these chains. The crystal structure of (II) belongs to the alluaudite type. Its open framework results from [Ni{sub 2}O{sub 10}] units of edge-sharing [NiO{sub 6}] octahedra, which alternate with [FeO{sub 6}] octahedra that form infinite chains. Coordination of these chains yields two distinct tunnels in which site Na{sup +}. The magnetization data of compound (I) reveal antiferromagnetic (AFM) interactions by the onset of deviations from a Curie-Weiss behaviour at low temperature as confirmed by Moessbauer measurements performed at 4.2 K. The corresponding temperature dependence of the reciprocal susceptibility {chi}{sup -1} follows a typical Curie-Weiss behaviour for T > 105 K. A canted AFM state is proposed for compound (II) below 46 K with a field-induced magnetic transition at H {approx} 19 kOe, revealed in the hysteresis loop measured at 5 K. This transition is most probably associated with a spin-flop transition.

  5. Structural studies of apatite-type oxide ion conductors doped with Cobalt

    OpenAIRE

    Tolchard, Julian; Sansom, Jonathan; Islam, Saiful; Slater, Peter

    2005-01-01

    A series of Co doped lanthanum silicate apatite-type phases, La9.83Si4.5Co1.5O26, La9.66Si5CoO26, La10Si5CoO26.5 and La8BaCoSi6O26, have been synthesised, and neutron diffraction, EXAFS and XANES used to investigate their structures in detail. All compositions were shown to possess the hexagonal apatite structure, and the results confirmed that cobalt can be doped onto both the La and Si sites within the structure depending on the starting composition. The Co doping is shown to cause consider...

  6. The electronic structure of zircon-type orthovanadates: Effects of high-pressure and cation substitution

    OpenAIRE

    Panchal, V.; Errandonea, D.; SEGURA, A.; Rodriguez-Hernandez, P.; Munoz, A.; Lopez-Moreno, S.; Bettinelli, M

    2012-01-01

    The electronic structure of four ternary-metal oxides containing isolated vanadate ions is studied. Zircon-type YVO4, YbVO4, LuVO4, and NdVO4 are investigated by high-pressure optical-absorption measurements up to 20 GPa. First-principles calculations based on density-functional theory were also performed to analyze the electronic band structure as a function of pressure. The electronic structure near the Fermi level originates largely from molecular orbitals of the vanadate...

  7. Crystal structure of alluaudite-type Na4Co(MoO4)3

    OpenAIRE

    Rawia Nasri; Noura Fakhar Bourguiba; Mohamed Faouzi Zid; Ahmed Driss

    2014-01-01

    The title compound, tetrasodium cobalt(II) tris[molybdate(IV)], was prepared by solid-state reactions. The structure is isotypic with Na3In2(AsO4)3 and Na3In2(PO4)3. The main structural feature is the presence of infinite chains of edge-sharing X2O10 (X = Co/Na) dimers, which are linked by MoO4 tetrahedra, forming a three-dimensional framework enclosing two types of hexagonal tunnels in which Na+ cations reside. In this alluaudite structure, Co and Na atoms are located at the same general sit...

  8. Crystal structure of alluaudite-type Na4Co(MoO4)3

    OpenAIRE

    Nasri, Rawia; Fakhar Bourguiba, Noura; Zid, Mohamed Faouzi; DRISS, Ahmed

    2014-01-01

    The title compound, tetra­sodium cobalt(II) tris­[molyb­date(IV)], was prepared by solid-state reactions. The structure is isotypic with Na3In2(AsO4)3 and Na3In2(PO4)3. The main structural feature is the presence of infinite chains of edge-sharing X 2O10 (X = Co/Na) dimers, which are linked by MoO4 tetra­hedra, forming a three-dimensional framework enclosing two types of hexa­gonal tunnels in which Na+ cations reside. In this alluaudite structure, Co and Na atoms are located at the same ge...

  9. The induced radioactivity of structure and shielding materials at NPPS with reactors of WWER-type

    International Nuclear Information System (INIS)

    The induced radioactivity of structural and shielding elements of WWER-type reactors (WWER-440, Unit 2, Armenian NPP) was considered. Taking into account specific reactor characteristics, the main activation reactions were identified. Results obtained from calculations of induced radioactivity are presented. (author)

  10. Expressibility of the logic SOF on classes of structures of bounded FO types

    OpenAIRE

    Grosso, Alejandro; Turull Torres, Jose? Mari?a

    2012-01-01

    We introduce a new property for classes of structures (or relational database instances), that we call bounded FO types. Then we prove that on such classes the expressive power of SOF collapses to rst order logic FO. As a consequence of this we prove that SOF is strictly included in SO.

  11. Structural Equation Modeling of Multitrait-Multimethod Data: Different Models for Different Types of Methods

    Science.gov (United States)

    Eid, Michael; Nussbeck, Fridtjof W.; Geiser, Christian; Cole, David A.; Gollwitzer, Mario; Lischetzke, Tanja

    2008-01-01

    The question as to which structural equation model should be selected when multitrait-multimethod (MTMM) data are analyzed is of interest to many researchers. In the past, attempts to find a well-fitting model have often been data-driven and highly arbitrary. In the present article, the authors argue that the measurement design (type of methods…

  12. Electronic structure of p-type (Ga,Fe)N diluted magnetic semiconductors

    Energy Technology Data Exchange (ETDEWEB)

    Mounkachi, O. [Laboratoire de Magnetisme et de Physique des Hautes Energies, Departement de physique, Faculte des sciences, B.P. 1014, Rabat (Morocco); Benyoussef, A. [Laboratoire de Magnetisme et de Physique des Hautes Energies, Departement de physique, Faculte des sciences, B.P. 1014, Rabat (Morocco); Hassan II Academy of Sciences and Technology, Rabat (Morocco); The Institute of Nanotechnology, INANOTECH, Rabat (Morocco); El Kenz, A. [Laboratoire de Magnetisme et de Physique des Hautes Energies, Departement de physique, Faculte des sciences, B.P. 1014, Rabat (Morocco)], E-mail: elkenz@fsr.ac.ma; Saidi, E.H. [Laboratoire de Physique des Hautes Energies, Departement de physique, Faculte des sciences, B.P. 1014, Rabat (Morocco); Hassan II Academy of Sciences and Technology, Rabat (Morocco); The Institute of Nanotechnology, INANOTECH, Rabat (Morocco)

    2009-08-15

    By ab-initio calculation we show that the (Ga,Fe)N ground state may be changed from anti-ferromagnetic to ferromagnetic by acceptor defect like Ga vacancies. The electronic structures are calculated by using the Korringa-Kohn-Rostoker (KKR) method combined with coherent potential approximation (CPA). We show that we can increase the magnetic moment of Fe in p-type GaN by oxygen co-doping. Mechanism of exchange interactions between magnetic ions in p-type (Ga,Fe)N is also studied. The effect of external magnetic field on the electronic structure of (Ga, Fe)N and p-type (Ga, Fe)N is investigated.

  13. Electronic structure of p-type (Ga,Fe)N diluted magnetic semiconductors

    International Nuclear Information System (INIS)

    By ab-initio calculation we show that the (Ga,Fe)N ground state may be changed from anti-ferromagnetic to ferromagnetic by acceptor defect like Ga vacancies. The electronic structures are calculated by using the Korringa-Kohn-Rostoker (KKR) method combined with coherent potential approximation (CPA). We show that we can increase the magnetic moment of Fe in p-type GaN by oxygen co-doping. Mechanism of exchange interactions between magnetic ions in p-type (Ga,Fe)N is also studied. The effect of external magnetic field on the electronic structure of (Ga, Fe)N and p-type (Ga, Fe)N is investigated.

  14. Relationship between the structural stability with the types and land uses in southeastern Spain

    International Nuclear Information System (INIS)

    Structural stability is one of the most important physical properties and is proposed as an indicator of quality. The aim of this study is to see the possible relationship between this property with soil types and uses of them. In this paper we have selected the Mazarron area based on their environmental characteristics and has taken forty-one topsoil samples, after analysis and study of the relationship between its structural stability with soil types and uses of same, we find a closer relationship in the case of uses that type, so that the natural soil as the percentage of stable aggregates close to 75%, while in soils anthropized this value reaches 44 %. (Author) 6 refs

  15. Crystal structure of alluaudite-type Na4Co(MoO43

    Directory of Open Access Journals (Sweden)

    Rawia Nasri

    2014-09-01

    Full Text Available The title compound, tetrasodium cobalt(II tris[molybdate(IV], was prepared by solid-state reactions. The structure is isotypic with Na3In2(AsO43 and Na3In2(PO43. The main structural feature is the presence of infinite chains of edge-sharing X2O10 (X = Co/Na dimers, which are linked by MoO4 tetrahedra, forming a three-dimensional framework enclosing two types of hexagonal tunnels in which Na+ cations reside. In this alluaudite structure, Co and Na atoms are located at the same general site with occupancies of 0.503?(5 and 0.497?(6, respectively. The other three Na and one of the two Mo atoms lie on special positions (site symmetries 2, -1, 2 and 2, respectively. The structure is compared with similar structures and other members of alluaudite family.

  16. Croatian banking sector research: relationship between ownership structure, concentration, owners’ type and bank performance

    Directory of Open Access Journals (Sweden)

    Igor Tomi?i?

    2012-12-01

    Full Text Available Banks are important financial intermediaries of any national economy, and corporate governance has an important role in banking sector; especially due to processes of the globalization and the internationalization, and also because of the sensitivity of the activities between the interest groups. The objective of this paper is to examine the relationship between ownership structure, concentration, owners’ type and bank performance. The authors made a research of banks' ownership structure using publicly available data. Using statistical tools authors discovered relationships between bank ownership structure and bank performance indicators (average asset, total asset, average equity, profit (loss before taxes, profit (loss after taxes, ROAA, ROAE. Further they discuss the relationships between ownership structure and a number of consequences for the bank performance. The authors discovered significant correlation between bank ownership structure and performance indicators variables that are described in the paper.

  17. Population structure of Lactobacillus helveticus isolates from naturally fermented dairy products based on multilocus sequence typing.

    Science.gov (United States)

    Sun, Zhihong; Liu, Wenjun; Song, Yuqin; Xu, Haiyan; Yu, Jie; Bilige, Menghe; Zhang, Heping; Chen, Yongfu

    2015-05-01

    Lactobacillus helveticus is an economically important lactic acid bacterium used in industrial dairy fermentation. In the present study, the population structure of 245 isolates of L. helveticus from different naturally fermented dairy products in China and Mongolia were investigated using an multilocus sequence typing scheme with 11 housekeeping genes. A total of 108 sequence types were detected, which formed 8 clonal complexes and 27 singletons. Results from Structure, SplitsTree, and ClonalFrame software analyses demonstrated the presence of 3 subpopulations in the L. helveticus isolates used in our study, namely koumiss, kurut-tarag, and panmictic lineages. Most L. helveticus isolates from particular ecological origins had specific population structures. PMID:25726109

  18. In and out of the cation pumps: P-type ATPase structure revisited.

    DEFF Research Database (Denmark)

    Bublitz, Maike; Poulsen, Hanne

    2010-01-01

    Active transport across membranes is a crucial requirement for life. P-type ATPases build up electrochemical gradients at the expense of ATP by forming and splitting a covalent phosphoenzyme intermediate, coupled to conformational changes in the transmembrane section where the ions are translocated. The marked increment during the last three years in the number of crystal structures of P-type ATPases has greatly improved our understanding of the similarities and differences of pumps with different ion specificities, since the structures of the Ca2+-ATPase, the Na+,K+-ATPase and the H+-ATPase can now be compared directly. Mechanisms for ion gating, charge neutralization and backflow prevention are starting to emerge from comparative structural analysis; and in combination with functional studies of mutated pumps this provides a framework for speculating on how the ions are bound and released as well as on how specificity is achieved.

  19. Appurtenance Influence on Type III Hanford Single-Shell Tank Structural Integrity - 12255

    International Nuclear Information System (INIS)

    The interim stabilized Hanford Single-Shell Tanks (SSTs) are currently undergoing a state of the art analysis to assess the structural integrity of the waste storage tanks, for cleanup and closure operations, considering their adverse thermal histories and an updated seismic hazard for the Hanford Site near Richland, Washington. The SSTs contain a variety of ancillary pits, piping, piping supports, risers, equipment, and penetrations known as appurtenances. These appurtenances may alter the structural response and ultimately could affect the structural integrity of the SSTs. An important challenge to the structural analysis of the SSTs is to determine the impact of these appurtenances on structural integrity. To achieve this, the various appurtenances were reviewed and a bounding appurtenance configuration for the SST Type III tanks was analyzed using finite element models for both thermal and operating loads as well as seismic loads. Tank structural demands from the finite element analyses were evaluated according to American Concrete Institute (ACI-349) code requirements to determine the tank structural integrity. The appurtenances configuration is found to increase the demand to capacity ratios in local regions near the appurtenances. Away from the appurtenances the influence on structural integrity is minor. The ACI-349-06 evaluation of the Type III SST bounding appurtenance configuration shows the tank is still structurally sound under all evaluated load combinations. When the appurtenance model D/C ratios were compared to those from the baseline axisymmetric model it was found that there were significant differences in the results, particularly under seismic loading conditions. This indicates that the effect of appurtenances on tank structural integrity should at least be considered in all SST AORs. (authors)

  20. Crystal structure of Sc5Ga4 and new compounds of Ho11Ge10 structural type

    International Nuclear Information System (INIS)

    X-ray diffraction analysis (of monocrystal and powder) is used to determine crystal structure of earlier known Sc5Ga4 and Hf5Ga4 compounds and ternary X'-phases forming inSc-Ti(Zr,Nb)-Ga and Zr-Ti(V)-Ga systems. Sc5Ga4 compound belongs to Ho11Ge10 structural type (a=1.0366, c=1.5305 nm) with deficit of gallium atoms (the correct point system 16(m) is occupied only by 12 gallium atoms). Composition of Hf5Ga4 compound is actually described by Hf11Ga10 formula and Ho11Ge10 structure. For X'-phases homogeneity regions are defined more exactly, and it is shown that their structure belongs to Ho11Ge10 type. In Sc-Ti(Zr,Nb)-Ga systems both ternary X'-phases and solid solutions on the basis of Sc5Ga4 compound are formed and in Sc-Hf-Ga system two solid solutions on Sc5Ga4 and Hf11Ga10 basis are in equilibrium

  1. Mesothelin, Stereocilin, and Otoancorin are predicted to have superhelical structures with ARM-type repeats

    Directory of Open Access Journals (Sweden)

    Pastan Ira

    2009-01-01

    Full Text Available Abstract Background Mesothelin is a 40 kDa protein present on the surface of normal mesothelial cells and overexpressed in many human tumours, including mesothelioma and ovarian and pancreatic adenocarcinoma. It forms a strong and specific complex with MUC16, which is also highly expressed on the surface of mesothelioma and ovarian cancer cells. This binding has been suggested to be the basis of ovarian cancer metastasis. Knowledge of the structure of this protein will be useful, for example, in building a structural model of the MUC16-mesothelin complex. Mesothelin is produced as a precursor, which is cleaved by furin to produce the N-terminal half, which is called the megakaryocyte potentiating factor (MPF, and the C-terminal half, which is mesothelin. Little is known about the function of mesothelin and there is no information on its possible three-dimensional structure. Mesothelin has been reported to be homologous to the deafness-related inner ear proteins otoancorin and stereocilin, for neither of which the three-dimensional structure is known. Results The BLAST and PSI-BLAST searches confirmed that mesothelin and mesothelin precursor proteins are remotely homologous to stereocilin and otoancorin and more closely homologous to the hypothetical protein MPFL (MPF-like. Secondary structure prediction servers predicted a predominantly helical structure for both mesothelin and mesothelin precursor proteins and also for stereocilin and otoancorin. Three-dimensional structure prediction servers INHUB and I-TASSER produced structural models for mesothelin, which consisted of superhelical structures with ARM-type repeats in conformity with the secondary structure predictions. Similar ARM-type superhelical repeat structures were predicted by 3D-PSSM server for mesothelin precursor and for stereocilin and otoancorin proteins. Conclusion The mesothelin superfamily of proteins, which includes mesothelin, mesothelin precursor, megakaryocyte potentiating factor, MPFL, stereocilin and otoancorin, are predicted to have superhelical structures with ARM-type repeats. We suggest that all of these function as superhelical lectins to bind the carbohydrate moieties of extracellular glycoproteins.

  2. Study of the FIV exciting force on lower plenum structures of internal-pump-type BWRs

    International Nuclear Information System (INIS)

    In internal-pump-type boiling water reactors (BWRs), core coolant flows from the reactor internal pumps to structures in the lower plenum. The discharged flow from the pump is fed to such structures as the control rod guide tubes (CRGTs) and the in-core monitor guide tubes (ICMGTs), which causes flow-induced vibration (FIV) of these structures. The exciting force for the FIV around the lower structures. The exciting force for the FIV around the lower plenum structures is examined. Many pumps are installed in the annulus region between the reactor pressure vessel (RPV) and the core shroud, and the discharged flow is fed to the common lower plenum region. The discharged flow, which induces flow vibration, is strongly affected by the pump exit configurations. Flow-induced vibration exciting forces for identical CRGTs, located at different interpump discharge configurations, are examined. Water flow tests, using a one-fifth (360-deg) scale model, were performed to evaluate the exciting force on the lower plenum structures. Models of the reactor internal pump, the CRGT, and the ICMGT were installed. The flow path configuration was similar to that of an actual internal-pump-type BWR

  3. The structure of the R8 term in type IIB string theory

    International Nuclear Information System (INIS)

    Based on the structure of the on-shell linearized superspace of type IIB supergravity, we argue that there is a non-BPS 16 derivative interaction in the effective action of type IIB string theory of the form (t8t8R4)2, which we call the R8 interaction. It lies in the same supermultiplet as the G8R4 interaction. Using the Kawai–Lewellen–Tye relation, we analyze the structure of the tree level eight-graviton scattering amplitude in the type IIB theory, which leads to the R8 interaction at the linearized level. This involves an analysis of color-ordered multi-gluon disc amplitudes in the type I theory, which shows an intricate pole structure and transcendentality consistent with various other interactions. Considerations of S-duality show that the R8 interaction receives non-analytic contributions in the string coupling at one and two loops. Apart from receiving perturbative contributions, we show that the R8 interaction receives a non-vanishing contribution in the one D-instanton-anti-instanton background at leading order in the weak coupling expansion. (paper)

  4. High-pressure structural investigation of several zircon-type orthovanadates

    CERN Document Server

    Errandonea, D; Ruiz-Fuertes, J; Segura, A; Achary, S N; Tyagi, A K; 10.1103/PhysRevB.79.184104

    2010-01-01

    Room temperature angle-dispersive x-ray diffraction measurements on zircon-type EuVO4, LuVO4, and ScVO4 were performed up to 27 GPa. In the three compounds we found evidence of a pressure-induced structural phase transformation from zircon to a scheelite-type structure. The onset of the transition is near 8 GPa, but the transition is sluggish and the low- and high-pressure phases coexist in a pressure range of about 10 GPa. In EuVO4 and LuVO4 a second transition to a M-fergusonite-type phase was found near 21 GPa. The equations of state for the zircon and scheelite phases are also determined. Among the three studied compounds, we found that ScVO4 is less compressible than EuVO4 and LuVO4, being the most incompressible orthovanadate studied to date. The sequence of structural transitions and compressibilities are discussed in comparison with other zircon-type oxides.

  5. Integrability of and differential–algebraic structures for spatially 1D hydrodynamical systems of Riemann type

    International Nuclear Information System (INIS)

    Highlights: • A new differential–algebraic–geometric approach for testing integrability is described. • The approach is applied to a generalized Riemann type hydrodynamic system. • The approach is applied to a generalized Ostrovsky–Vakhnenko system. • The approach is applied to a new two-component Burgers type hydrodynamic system. -- Abstract: A differential–algebraic approach to studying the Lax integrability of a generalized Riemann type hydrodynamic hierarchy is revisited and a new Lax representation is constructed. The related bi-Hamiltonian integrability and compatible Poissonian structures of this hierarchy are also investigated using gradient-holonomic and geometric methods. The complete integrability of a new generalized Riemann hydrodynamic system is studied via a novel combination of symplectic and differential–algebraic tools. A compatible pair of polynomial Poissonian structures, a Lax representation and a related infinite hierarchy of conservation laws are obtained. In addition, the differential–algebraic approach is used to prove the complete Lax integrability of the generalized Ostrovsky–Vakhnenko and a new Burgers type system, and special cases are studied using symplectic and gradient-holonomic tools. Compatible pairs of polynomial Poissonian structures, matrix Lax representations and infinite hierarchies of conservation laws are derived

  6. Structure-activity relationships of lanostane-type triterpenoids from Ganoderma lingzhi as ?-glucosidase inhibitors.

    Science.gov (United States)

    Fatmawati, Sri; Kondo, Ryuichiro; Shimizu, Kuniyoshi

    2013-11-01

    A series of lanostane-type triterpenoids, identified as ganoderma alcohols and ganoderma acids, were isolated from the fruiting body of Ganoderma lingzhi. Some of these compounds were confirmed as active inhibitors of the in vitro human recombinant aldose reductase. This paper aims to explain the structural requirement for ?-glucosidase inhibition. Our structure-activity studies of ganoderma alcohols showed that the OH substituent at C-3 and the double-bond moiety at C-24 and C-25 are necessary to increase ?-glucosidase inhibitory activity. The structure-activity relationships of ganoderma acids revealed that the OH substituent at C-11 is an important feature and that the carboxylic group in the side chain is essential for the recognition of ?-glucosidase inhibitory activity. Moreover, the double-bond moiety at C-20 and C-22 in the side chain and the OH substituent at C-3 of ganoderma acids improve ?-glucosidase inhibitory activity. These results provide an approach with which to consider the structural requirements of lanostane-type triterpenoids from G. lingzhi. An understanding of these requirements is considered necessary in order to improve a new type of ?-glucosidase inhibitor. PMID:24070782

  7. The structure of the polysaccharide of the lipopolysaccharide produced by Taylorella equigenitalis type strain (ATCC 35865).

    Science.gov (United States)

    Vinogradov, Evgeny; MacLean, Leann L; Brooks, Brian W; Lutze-Wallace, Cheryl; Perry, Malcolm B

    2008-12-01

    Taylorella equigenitalis is a Gram-negative bacterium that causes venereally transmitted contagious equine metritis (CEM), and its identification and differentiation from other bacteria and Taylorella species is an important requirement for the control of CEM infection. Based on the results of NMR and MS analysis, the antigenic O-polysaccharide (O-PS) component of the lipopolysaccharide (LPS) produced by the type strain T. equigenitalis (ATCC 35865) was found to be a linear polymer composed of a repeating disaccharide unit, containing partially amidated 2,3-diacetamido-2,3-dideoxy-alpha-L-guluronic and 2,3-diacetamido-2,3-dideoxy-beta-D-mannuronic acids, terminated with a 4-O-methylated non-reducing Gulp-NAc3NAcA residue, and has the structure [structure: see text]. The O-PS of the type strain T. equigenitalis LPS provides a specific antigenic marker for the discrimination of the pathogen from the related type strain of T. asinigenitalis sp. nov, a phenotypically indistinguishable non-pathogenic bacterium having a serologically and structurally unrelated LPS O-antigen. The analysis of a structurally unusual core oligosaccharide of the LPS is also reported. PMID:18950750

  8. Mutant protein A30P ?-synuclein adopts wild-type fibril structure, despite slower fibrillation kinetics.

    Science.gov (United States)

    Lemkau, Luisel R; Comellas, Gemma; Kloepper, Kathryn D; Woods, Wendy S; George, Julia M; Rienstra, Chad M

    2012-03-30

    ?-Synuclein (AS) is associated with both sporadic and familial forms of Parkinson disease (PD). In sporadic disease, wild-type AS fibrillates and accumulates as Lewy bodies within dopaminergic neurons of the substantia nigra. The accumulation of misfolded AS is associated with the death of these neurons, which underlies many of the clinical features of PD. In addition, a rare missense mutation in AS, A30P, is associated with highly penetrant, autosomal dominant PD, although the pathogenic mechanism is unclear. A30P AS fibrillates more slowly than the wild-type (WT) protein in vitro and has been reported to preferentially adopt a soluble, protofibrillar conformation. This has led to speculation that A30P forms aggregates that are distinct in structure compared with wild-type AS. Here, we perform a detailed comparison of the chemical shifts and secondary structures of these fibrillar species, based upon our recent characterization of full-length WT fibrils. We have assigned A30P AS fibril chemical shifts de novo and used them to determine its secondary structure empirically. Our results illustrate that although A30P forms fibrils more slowly than WT in vitro, the chemical shifts and secondary structure of the resultant fibrils are in high agreement, demonstrating a conserved ?-sheet core. PMID:22334684

  9. Structural Comparison of n-type and p-type LaAlO3/SrTiO3 Interfaces

    Energy Technology Data Exchange (ETDEWEB)

    Bell, Christopher

    2011-08-19

    Using a surface x-ray diffraction technique, we investigated the atomic structure of two types of interfaces between LaAlO{sub 3} and SrTiO{sub 3}, that is, p-type (SrO/AlO{sub 2}) and n-type (TiO{sub 2}/LaO) interfaces. Our results demonstrate that the SrTiO{sub 3} in the sample with the n-type interface has a large polarized region, while that with the p-type interface has a limited polarized region. In addition, the atomic intermixing was observed to extend deeper into STO substrate at the n-type interface than at the p-type. These differences result in different degrees of band bending, which likely contributes to the striking difference in electrical conductivity between the two types of interfaces.

  10. GP3 is a structural component of the PRRSV type II (US) virion

    International Nuclear Information System (INIS)

    Glycoprotein 3 (GP3) is a highly glycosylated PRRSV envelope protein which has been reported as being present in the virions of PRRSV type I, while missing in the type II PRRSV (US) virions. We herein present evidence that GP3 is indeed incorporated in the virus particles of a North American strain of PRRSV (FL12), at a density that is consistent with the minor structural role assigned to GP3 in members of the Arterivirus genus. Two 15aa peptides corresponding to two different immunodominant linear epitopes of GP3 derived from the North American strain of PRRSV (FL12) were used as antigen to generate a rabbit monospecific antiserum to this protein. The specificity of this anti-GP3 antiserum was confirmed by radioimmunoprecipitation (RIP) assay using BHK-21 cells transfected with GP3 expressing plasmid, MARC-145 cells infected with FL12 PRRSV, as well as by confocal microscopy on PRRSV-infected MARC-145 cells. To test if GP3 is a structural component of the virion, 35S-labelled PRRSV virions were pelleted through a 30% sucrose cushion, followed by a second round of purification on a sucrose gradient (20-60%). Virions were detected in specific gradient fractions by radioactive counts and further confirmed by viral infectivity assay in MARC 145 cells. The GP3 was detected in gradient fractions containing purified virions by RIP using anti-GP3 antiserum. Predictably, the GP3 was less abundant in purified virions than other major structural envelope proteins sucher major structural envelope proteins such as GP5 and M. Further evidence of the presence of GP3 at the level of PRRSV FL12 envelope was obtained by immunogold staining of purified virions from the supernatant of infected cells with anti-GP3 antiserum. Taken together, these results indicate that GP3 is a minor structural component of the PRRSV type II (FL12 strain) virion, as had been previously described for PRRSV type I.

  11. Habitat Evaluation on Scour Hole Downflow Low Drop Structure Types Using Large-Scale Experiment

    Directory of Open Access Journals (Sweden)

    Joongu Kang

    2012-09-01

    Full Text Available This study sought to review whether large-scale experimentation can apply to actual rivers concerning the effect of topographical change by scour in the downstream area of natural-type low drop structures on the fish habitat. The large-scale applicability experiment performed in this study installed low drop structures as the study object within the experiment channel and precisely surveyed topography in the downstream area of drop structures along with the hydraulic amount including water level and flow velocity under certain flow conditions. Based on topographical data acquired through the survey after the experiment ended, this study reviewed the change of suitability index and difference of weighted usable area by performing 2D habitat simulation. Ultimately, through the habitat simulation results in cases of considering and not considering scour in the downstream area of drop structures, this study analyzed the effects of topographical change in actual rivers on the habitat.

  12. Structural studies of apatite-type oxide ion conductors doped with cobalt.

    Science.gov (United States)

    Tolchard, Julian R; Sansom, Jonathan E H; Islam, M Saiful; Slater, Peter R

    2005-04-01

    A series of Co doped lanthanum silicate apatite-type phases, La9.83Si4.5Co1.5O26, La9.66Si5CoO26, La10Si5CoO26.5 and La8BaCoSi6O26, have been synthesised, and neutron diffraction, EXAFS and XANES used to investigate their structures in detail. All compositions were shown to possess the hexagonal apatite structure, and the results confirmed that cobalt can be doped onto both the La and Si sites within the structure depending on the starting composition. The Co doping is shown to cause considerable local distortions within the apatite structure. In the case of Si site doping two compositions showed anisotropic peak broadening, which has been attributed to incommensurate ordering of oxygen within the apatite channels. PMID:15782264

  13. THE INFLUENCES OF THE SLAB DISCONTINUITIES ON THE INTERNAL FORCES, AT FRAME TYPE REINFORCED CONCRETE STRUCTURES

    Directory of Open Access Journals (Sweden)

    Mehmet TERZ?

    2006-03-01

    Full Text Available To resist earthquake forces in a confidential manner is one of the fundamental requirements of the structural system design of buildings. The main principles of Earthquake-resistant design of buildings have the symetric plan and regular configuration of the structural system. Regular buildings are easier in application, for designing, dimensioning of structural elements and much more economic for consruction cost. Also, the results of the structural system analysis of regular buildings represent the behaviour of the real structure. For these reasons, regular buildings are prefered for the best building design and analysis. Vertical and horizontal discontinuities in building structures, instant stiffness changes and variation of mass distribution are negative states, display good seismic behaviour. The buildings having irregularities in plan and in elevation are accepted as non-regular buildings. In practise, non-regular buildings are not economic in construction cast, lead to stress concentrations hazardous to the structure and causing erroneous application. If the basic methods of structural analysis for regular buildings are applied to non-regular buildings the effects of irregularities must be considered. Analysis of the regular frame type structural systems according to The Turkish earthquake code is performed on a lineer elastic model assuming different cavity ratios of the floor slab by using SAP2000 Structural Analysis Programme applying simplified modal response spectrum analysis methods. Numerical results of the internal forces of the elements of the structural system are obtained and compared for two different casses in one case the floor diaphragms are sufficiently rigid in their plane, in the other case unsuffiently rigid in their plane.

  14. Structural basis for recognition of urokinase-type plasminogen activator by plasminogen activator inhibitor-1

    DEFF Research Database (Denmark)

    Lin, Zhonghui; Jiang, Longguang

    2011-01-01

    Plasminogen activator inhibitor-1 (PAI-1), together with its physiological target urokinase-type plasminogen activator (uPA), plays a pivotal role in fibrinolysis, cell migration, and tissue remodeling and is currently recognized as being among the most extensively validated biological prognostic factors in several cancer types. PAI-1 specifically and rapidly inhibits uPA and tissue-type PA (tPA). Despite extensive structural/functional studies on these two reactions, the underlying structural mechanism has remained unknown due to the technical difficulties of obtaining the relevant structures. Here, we report a strategy to generate a PAI-1·uPA(S195A) Michaelis complex and present its crystal structure at 2.3-Å resolution. In this structure, the PAI-1 reactive center loop serves as a bait to attract uPA onto the top of the PAI-1 molecule. The P4-P3' residues of the reactive center loop interact extensively with the uPA catalytic site, accounting for about two-thirds of the total contact area. Besides the active site, almost all uPA exosite loops, including the 37-, 60-, 97-, 147-, and 217-loops, are involved in the interaction with PAI-1. The uPA 37-loop makes an extensive interaction with PAI-1 ?-sheet B, and the 147-loop directly contacts PAI-1 ?-sheet C. Both loops are important for initial Michaelis complex formation. This study lays down a foundation for understanding the specificity of PAI-1 for uPA and tPA and provides a structural basis for further functional studies.

  15. Plate-like structure formation in single crystals of magnetic alloy type YuNDKT

    International Nuclear Information System (INIS)

    Specific features of structure and dendritic-cellular segregation were studied in ALNICO alloy single crystals grown by directional crystallization technique. X-ray diffraction studied showed that castings of YuNDK35T5+0.2%S alloy consisted of ?'- and ?-phases and had lamellar structure. Crystallization was revealed to proceed with formation of eutectics. Sulfur alloying promoted a decrease of segregation in dendritic calls of ?-phase and so enhanced magnetic properties of the alloy. Results of microscopical examination and X-ray analysis of ALNICO type alloys with sulfur addition are presented. 14 refs., 5 figs., 2 tabs

  16. Stability of Fe-based alloys with structure type C6Cr23

    CERN Document Server

    Widom, M

    2004-01-01

    Bulk metallic glass forms when liquid metal alloys solidify without crystalization. In the search for Iron-based bulk glass-forming alloys of the metal-metalloid type (Fe-B- and Fe-C-based), crystals based on the structural prototype C6Cr23 often preempt the amorphous phase. Destabilizing this competing crystal structure could enhance glass-formability. We carry out first-principles total energy calculations of enthalpy of formation to identify third elements that can effectively destabilize C6Cr23. Yttrium appears optimal among transition metals, and rare earths also are suitable. Atomic size is the dominant factor.

  17. On low-frequency buneman type instability in slowing-down structure

    International Nuclear Information System (INIS)

    A possibility of decreasing the threshold current of Buneman instability for relativistic electron beam in slowing-down structure is investigated. On the basis of solving the dispersion equation taking into account the boundary conditions in a system of spiral waveguide with magneto dielectric it is shown analytically and numerically that due to the beam interaction with structure a low-frequency instability of Buneman type may appear independently on the ion presence. Under certain conditions the instability could loss its threshold character, the wave having a small phase velocity and a rather big increment

  18. Optical properties of delta poly-type quasiregular dielectric structures made of porous silicon

    Energy Technology Data Exchange (ETDEWEB)

    Agarwal, V.; Escorcia-Garcia, J. [CIICAP-UAEM, Av. Universidad 1001, Col. Chamilpa, CP 62209, Cuernavaca, Morelos (Mexico); Mora-Ramos, Miguel E. [Facultad de Ciencias-UAEM, Av. Universidad 1001, Col. Chamilpa, CP 62209, Cuernavaca, Morelos (Mexico)

    2007-05-15

    To investigate the reflection of light in quasi-regular dielectrics, we study here the optical properties of porous-silicon-based Fibonacci, Thue-Morse and Period Doubling heterostructures. The multilayered systems are fabricated in such a way that each element in the two-block substitutional sequence has a poly-type structure. Both delta-like and traditional configurations are considered. The results for the optical transmittance are analyzed and compared with the classical periodic structure. Numerical simulation for the transmittance along the lines of the transfer matrix approach is also presented. (copyright 2007 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  19. Ridge-type AlGaInN-based laser diode structure by selective regrowth

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Wei; Detchprohm, Theeradetch; Hou, Wenting; Li, Yufeng; Wetzel, Christian [Future Chips Constellation, Rensselaer Polytechnic Institute, Troy, NY 12180 (United States); Department of Physics, Applied Physics and Astronomy, Rensselaer Polytechnic Institute, Troy, NY 12180 (United States)

    2011-07-15

    We report the development of a novel ridge-type AlGaInN-based laser diode structure fabricated by a metal organic vapor phase epitaxial regrowth method. The selective-area regrowth of AlGaN was optimized and compared with regular planar growth. An AlN fraction of 13% in the regrown ridge was concluded from the cathodoluminescence spectrum. The laser diode structure showed superluminescence at 465 nm under optical excitation. Under electrical excitation a super-linear increase of the light output power was observed. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  20. Structural integrity of primary piping system of top entry type FBR

    International Nuclear Information System (INIS)

    The top entry type loop reactor is the characteristic structural concept of the Japanese demonstration FBR. The major characteristic of this reactor is the reverse U-shaped piping system connecting the reactor vessel, intermediate heat exchanger vessels and pump vessels as shown in Fig.l. The top entry piping system reduces a number of elbows and provide a couple of rod-type restraint devices at the middle of the horizontal piping in each leg. This means that the thermal expansion stress in the piping tends to increase. For this reason, the design for reducing this stress is one of the important items dominating the feasibility of the top entry piping. On the other hand, the aseismic design is also required for severe earthquake. This paper describes the structural integrity of the primary piping system for thermal and seismic loads. (author)

  1. New Type Phase Transition of Li2RuO3 with Honeycomb Structure

    CERN Document Server

    Miura, Y; Sato, M; Igawa, N; Kakurai, K; Miura, Yoko; Yasui, Yukio; Sato, Masatoshi; Igawa, Naoki; Kakurai, Kazuhisa

    2006-01-01

    A new-type structural transition has been found in Li2RuO3 with honeycomb lattice of edge-sharing RuO6-octahedra. With decreasing temperature T, the electrical resistivity exhibits an anomalous increase at T=Tc~540 K, suggesting the (metal to insulator)-like transition and the magnetic susceptibility also shows a sharp decrease. Detailed structure analyses have revealed that the high temperature space group C2/m changes to P21/m at Tc. The most striking fact is that a significant reduction of the bond lengths is found between two of six Ru-Ru pairs of the hexagon in the low temperature phase, indicating a new type phase transition by the mechanism of the formation of molecular orbits of these Ru-Ru pairs.

  2. Crystal Structure of a Putative HTH-Type Transcriptional Regulator yxaF from Bacillus subtilis

    International Nuclear Information System (INIS)

    The New York Structural GenomiX Research Consortium (NYSGXRC) has selected the protein coded by yxaF gene from Bacillus subtilis as a target for structure determination. The yxaF protein has 191 residues with a molecular mass of 21 kDa and had no sequence homology to any structure in the Protein Data Bank (PDB) at the time of target selection. We aimed to elucidate the three-dimensional structure for the putative protein yxaF to better understand the relationship between protein sequence, structure, and function. This protein is annotated as a putative helix-turn-helix (HTH) type transcriptional regulator. Many transcriptional regulators like TetR and QacR use a structurally well-defined DNA-binding HTH motif to recognize the target DNA sequences. DNA-HTH motif interactions have been extensively studied. As the HTH motif is structurally conserved in many regulatory proteins, these DNA-protein complexes show some similarity in DNA recognition patterns. Many such regulatory proteins have a ligand-binding domain in addition to the DNA-binding domain. Structural studies on ligand-binding regulatory proteins provide a wealth of information on ligand-, and possibly drug-, binding mechanisms. Understanding the ligand-binding mechanism may help overcome problems with drug resistance, which represent increasing challenges in medicine. The protein encoded by yxaF, hereafter called T1414, shows fold similar to QacR repressor and TetR/CamR repressor and possesses putative DNA andR repressor and possesses putative DNA and ligand-binding domains. Here, we report the crystal structure of T1414 and compare it with structurally similar drug and DNA-binding proteins

  3. Structure of the minor pseudopilin XcpW from the Pseudomonas aeruginosa type II secretion system

    Energy Technology Data Exchange (ETDEWEB)

    Franz, Laura P.; Douzi, Badreddine; Durand, Eric; Dyer, David H.; Voulhouxd, Romé; Forest, Katrina T. (CNRS-UMR); (CNRS-CRMD); (UW)

    2012-01-13

    Pseudomonas aeruginosa utilizes the type II secretion machinery to transport virulence factors through the outer membrane into the extracellular space. Five proteins in the type II secretion system share sequence homology with pilin subunits of type IV pili and are called the pseudopilins. The major pseudopilin X{sub cp}T{sub G} assembles into an intraperiplasmic pilus and is thought to act in a piston-like manner to push substrates through an outer membrane secretin. The other four minor pseudopilins, X{sub cp}U{sub H}, X{sub cp}V{sub I}, X{sub cp}W{sub J} and X{sub cp}X{sub K}, play less well defined roles in pseudopilus formation. It was recently discovered that these four minor pseudopilins form a quaternary complex that is presumed to initiate the formation of the pseudopilus and to localize to its tip. Here, the structure of X{sub cp}W{sub J} was refined to 1.85 {angstrom} resolution. The structure revealed the type IVa pilin fold with an embellished variable antiparallel {beta}-sheet as also found in the X{sub cp}W{sub J} homologue enterotoxigenic Escherichia coli G{sub sp}J{sub W} and the X{sub cp}U{sub H} homologue Vibrio cholerae E{sub ps}U{sub H}. It is proposed that the exposed surface of this sheet may cradle the long N-terminal 1 helix of another pseudopilin. The final 31 amino acids of the X{sub cp}W{sub J} structure are instrinsically disordered. Deletion of this unstructured region of X{sub cp}W{sub J} did not prevent type II secretion in vivo.

  4. The Structure of Parental Involvement and Relations to Disease Management for Youth with Type 1 Diabetes

    OpenAIRE

    Palmer, Debra L.; Osborn, Peter; King, Pamela S.; Berg, Cynthia A.; Butler, Jorie; Butner, Jonathan; Horton, Dwayne; Wiebe, Deborah J.

    2010-01-01

    Objective?To test structural models of parental involvement in type 1 diabetes and to examine associations of parental involvement with adherence and metabolic control.?Methods?Two hundred and fifty-two young adolescents (10–14 years) completed reports of adherence and parents’ involvement: acceptance, independence encouragement, communication, general and diabetes-specific monitoring, frequency of help, and intrusive support. HbA1c values came from medical records.?Results?A mo...

  5. Physicochemical and structural characteristics of HEU-type zeolitic tuff treated by hydrochloric acid

    OpenAIRE

    MAGDALENA TOMASEVIC-CANOVIC; JOVAN LEMIC; ALEKSANDRA DAKOVIC; VERA DONDUR; ANA RADOSAVLJEVIC-MIHAJLOVIC

    2004-01-01

    Samples of natural HEU-type zeolites ? clinoptilolite-Ca, from the Novakovici deposit (near Prijedor, Bosnia and Herzegovina) were treated with the hydrochloric acid of various concentrations (from 10-3 M to 2 M). Zeolitic tuffs before and after the acid treatment were examined using IR, XRPD, and chemical analyses. The changes in the crystal structure of acid treated samples showed a significant reduction in the crystallinity of zeolitic tuffs (60?70 %), which were effected by hydrochloric...

  6. Structure-activity relationships of polybiguanides with activity against human immunodeficiency virus type 1

    OpenAIRE

    Passic, Shendra R.; Ferguson, Mary Lee; Catalone, Bradley J.; Kish-Catalone, Tina; Kholodovych, Vladyslav; Zhu, Wei; Welsh, William; Rando, Robert; Howett, Mary K.; Wigdahl, Brian; Labib, Mohamed; Fred C. Krebs

    2010-01-01

    Previous investigations showing that polydisperse biguanide (PDBG) molecules have activity against human immunodeficiency virus type 1 (HIV-1) also suggested a relationship between PDBG biologic activity and the lengths of hydrocarbon linkers surrounding the positively charged biguanide unit. To better define structure-activity relationships, PDBG molecules with select linker lengths were evaluated for cytotoxicity, anti-HIV-1 activity, and in vivo toxicity. Results of the in vitro experiment...

  7. Intra- and Intersubtype Alternative Pak2-Activating Structural Motifs of Human Immunodeficiency Virus Type 1 Nef

    OpenAIRE

    O'Neill, Eduardo; Baugh, Laura L.; Novitsky, Vladimir A.; Essex, Myron E.; Garcia, J. Victor

    2006-01-01

    The design of antiviral strategies against human immunodeficiency virus type 1 (HIV-1) has been largely derived from studies of subtype B viruses, although they constitute only 12% of infections worldwide. At 50% of all HIV-1 infections worldwide, subtype C viruses are the most predominant. Here, we present evidence that subtype C Nefs display functional Pak2-activating motifs that differ from those found in subtype B and E Nefs. The identification of multiple Pak2-activating structural motif...

  8. New phosphides of the Nb4CoSi type structure

    International Nuclear Information System (INIS)

    For the first time stated is the formation of Hf4FeP, Hf4CoP and TaFeP phosphides having the Nb4CoSi type structure. Binary intermetallic compounds TaCo, Ta2Ni, Zr2Co, Zr2Ni, Hf2Ni are shown to disslove up to 17 at.% P. Maximum composition of these solid solutions is characterized by ordered distribution of Co(or Ni)and P atoms

  9. Two Ethylenediamine-Templated Zeolite-Type Structures in Zinc Arsenate and Cobalt Phosphate Systems

    Science.gov (United States)

    Bu, Xianhui; Feng, Pingyun; Gier, Thurman E.; Stucky, Galen D.

    1998-03-01

    Hydrothermal syntheses and X-ray crystal structures of two zeolite-type structures encapsulating protonated ethylenediamine and consisting of three-dimensional 8-ring channels are presented. UCSB-3 and ACP-3 are isostructural and have zeolite-type topologies. The framework consists of cross-linked bifurcated hexagonal-square (bhs) chains, similar to that found in the zeolite-type structure, AlPO 4-D. Alternatively, like a number of zeolite structures such as ABW, gismondine, merlinoite, and phillipsite, the framework can be considered as superimposed 4.8 2nets. UCSB-3 is the only amine-templated arsenate with a zeolite-type topology. Crystal data for (H 3NCH 2CH 2NH 3) 0.5. ZnAsO 4(UCSB-3): M=235.35, space group P4 2/ n, a=10.7598(1) Å, c=9.1015(1) Å, V=1053.71(2) Å 3, Z=8, Dc=2.967 g cm -3, Mo K?, ?=0.71073 Å, ?=10.815 mm -1, 2 ?max=56.26°, R( F)=2.67% for 84 parameters and 1262 reflections with I>2 ?( I). Crystal data for (H 3NCH 2CH 2NH 3) 0.5(1- x) . Al xCo 1- xPO 4( x?0.15, ACP-3): space group P4 2/ n, a=10.4236(1) Å, c=8.9487(1) Å, V=972.29(2) Å 3, Z=8, Mo K?, 2 ?max=56.52°, R( F)=3.59% for 92 parameters and 1108 reflections with I>2 ?( I).

  10. Structural and functional cardiac changes in myotonic dystrophy type 1: a cardiovascular magnetic resonance study

    OpenAIRE

    Ce, Hermans Mieke; Faber Catharina G; Cam, Bekkers Sebastiaan; Em, Die-smulders Christine; Gerrits Monique M; Sj, Merkies Ingemar; Snoep Gabriel; Pinto Yigal M; Schalla Simon

    2012-01-01

    Abstract Background Myotonic dystrophy type 1 (MD1) is a neuromuscular disorder with potential involvement of the heart and increased risk of sudden death. Considering the importance of cardiomyopathy as a predictor of prognosis, we aimed to systematically evaluate and describe structural and functional cardiac alterations in patients with MD1. Methods Eighty MD1 patients underwent physical examination, electrocardiography (ECG), echocardiography and cardiovascular magnetic resonance (CMR). B...

  11. Structural and Genetic Characterization of Glycosylation of Type a Flagellin in Pseudomonas aeruginosa

    OpenAIRE

    Schirm, M.; Arora, S. K.; Verma, A; VINOGRADOV, E; Thibault, P.; Ramphal, R; Logan, S. M.

    2004-01-01

    Type a flagellins from two strains of Pseudomonas aeruginosa, strains PAK and JJ692, were found to be glycosylated with unique glycan structures. In both cases, two sites of O-linked glycosylation were identified on each monomer, and these sites were localized to the central, surface-exposed domain of the monomer in the assembled filament. The PAK flagellin was modified with a heterogeneous glycan comprising up to 11 monosaccharide units that were O linked through a rhamnose residue to the pr...

  12. Structure and mechanism of Zn2+-transporting P-type ATPases

    DEFF Research Database (Denmark)

    Wang, Kaituo; Sitsel, Oleg

    2014-01-01

    Zinc is an essential micronutrient for all living organisms. It is required for signalling and proper functioning of a range of proteins involved in, for example, DNA binding and enzymatic catalysis. In prokaryotes and photosynthetic eukaryotes, Zn(2+)-transporting P-type ATPases of class IB (ZntA) are crucial for cellular redistribution and detoxification of Zn(2+) and related elements. Here we present crystal structures representing the phosphoenzyme ground state (E2P) and a dephosphorylation intermediate (E2·Pi) of ZntA from Shigella sonnei, determined at 3.2 Å and 2.7 Å resolution, respectively. The structures reveal a similar fold to Cu(+)-ATPases, with an amphipathic helix at the membrane interface. A conserved electronegative funnel connects this region to the intramembranous high-affinity ion-binding site and may promote specific uptake of cellular Zn(2+) ions by the transporter. The E2P structure displays a wide extracellular release pathway reaching the invariant residues at the high-affinity site, including C392, C394 and D714. The pathway closes in the E2·Pi state, in which D714 interacts with the conserved residue K693, which possibly stimulates Zn(2+) release as a built-in counter ion, as has been proposed for H(+)-ATPases. Indeed, transport studies in liposomes provide experimental support for ZntA activity without counter transport. These findings suggest a mechanistic link between PIB-type Zn(2+)-ATPases and PIII-type H(+)-ATPases and at the same time show structural features of the extracellular release pathway that resemble PII-type ATPases such as the sarcoplasmic/endoplasmic reticulum Ca(2+)-ATPase (SERCA) and Na(+), K(+)-ATPase. These findings considerably increase our understanding of zinc transport in cells and represent new possibilities for biotechnology and biomedicine.

  13. Structure and mechanism of Zn(2+)-transporting P-type ATPases

    DEFF Research Database (Denmark)

    Wang, Kaituo; Sitsel, Oleg

    2014-01-01

    Zinc is an essential micronutrient for all living organisms. It is required for signalling and proper functioning of a range of proteins involved in, for example, DNA binding and enzymatic catalysis. In prokaryotes and photosynthetic eukaryotes, Zn(2+)-transporting P-type ATPases of class IB (ZntA) are crucial for cellular redistribution and detoxification of Zn(2+) and related elements. Here we present crystal structures representing the phosphoenzyme ground state (E2P) and a dephosphorylation intermediate (E2·Pi) of ZntA from Shigella sonnei, determined at 3.2 Å and 2.7 Å resolution, respectively. The structures reveal a similar fold to Cu(+)-ATPases, with an amphipathic helix at the membrane interface. A conserved electronegative funnel connects this region to the intramembranous high-affinity ion-binding site and may promote specific uptake of cellular Zn(2+) ions by the transporter. The E2P structure displays a wide extracellular release pathway reaching the invariant residues at the high-affinity site, including C392, C394 and D714. The pathway closes in the E2·Pi state, in which D714 interacts with the conserved residue K693, which possibly stimulates Zn(2+) release as a built-in counter ion, as has been proposed for H(+)-ATPases. Indeed, transport studies in liposomes provide experimental support for ZntA activity without counter transport. These findings suggest a mechanistic link between PIB-type Zn(2+)-ATPases and PIII-type H(+)-ATPases and at the same time show structural features of the extracellular release pathway that resemble PII-type ATPases such as the sarcoplasmic/endoplasmic reticulum Ca(2+)-ATPase (SERCA) and Na(+), K(+)-ATPase. These findings considerably increase our understanding of zinc transport in cells and represent new possibilities for biotechnology and biomedicine.

  14. ?erenkov-type second-harmonic spectroscopy in random nonlinear photonic structures.

    Science.gov (United States)

    Ayoub, Mousa; Roedig, Philip; Koynov, Kaloian; Imbrock, Jörg; Denz, Cornelia

    2013-04-01

    We report on experimental and theoretical studies of ?erenkov-type second-harmonic generation in random nonlinear photonic structures with different two-dimensional distributions of the ferroelectric domains. We utilize ?erenkov-type second-harmonic generation spectroscopy to estimate the average ferroelectric domain size by analyzing the spatial Fourier spectrum of the domain patterns. This is measured by scanning the ?erenkov second-harmonic signal for different angles of incidence and light polarizations of the fundamental wave. By comparing the experimental results with numerically simulated Fourier spectra, the corresponding domain patterns are retrieved, which are in a good correspondence with images obtained by ?erenkov-type second-harmonic generation microscopy. PMID:23571912

  15. The relationship analysis of thrust structure and sandstone type uranium deposits at northern margin of qaidam basin

    International Nuclear Information System (INIS)

    The thrust belt at northern margin of the Qaidam basin is prospective area for finding sandstone-type uranium deposits. The structure is complicated, post-reformation is strong and thrust structure develops in this area. Single thrust structure, opposite thrust structure, recoil structure and slope zone are the most common structural patterns. The different of tectonic style causes differences in occurrence and thickness of sedimentary strata and effects the metallogenic environment of sandstone-type uranium deposits. By analyzing the different between the tectonic style and uranium mineralization, it shows that uranium prospecting works deployment vary with the different of thrust tectonic styles. (authors)

  16. Preliminary structural analysis on the sealed basket type instrumented capsule for fuel irradiation tests in HANARO

    International Nuclear Information System (INIS)

    To develop the sealed basket type instrumented capsule to be used for the irradiation test of various nuclear fuels, it is necessary to ensure the compatibility of the capsule with HANARO and the structural integrity of the capsule. The dimensions of the sealed basket type instrumented capsule were determined on the basis of the pressure drop criteria in OR test hole of HANARO(mass flow rate m200kPa). From the buckling stability analysis for this capsule, the critical buckling load Pcr was 6.8kN. The vertical impact stress of the capsule under unit impact load was evaluated by the transient analysis, and the maximum vertical impact load calculated from the impact stress and the allowable stress was 60.4kN. Under the loading of the calculated Pcr, the maximum vertical impact stress was 19.3MPa. The structural integrity of the capsule under a horizontal impact loading was also examined. The mechanical stresses occurred by the pressure difference at the inner and outer surface of outer tube and by the coolant pressure at the surface of outer tube were 3.6MPa and 60.2MPa, respectively. These stress values were lower than the allowable stress in each case. Therefore, it was ensured that the sealed basket type instrumented capsule for the irradiation test of various nuclear fuels met the criteria on the structural integrity during installing and testing in HANARO

  17. Cybernetic preductoon of AB2Ge2 composition germanides with ThCr2Si2 type crystal structure

    International Nuclear Information System (INIS)

    The prediction of AB2Ge2 composition ternary compounds with a crystalline structure of the ThCr2Si2 type has been accomplished using the training computer. The predicting table fragment containing the greatest number of forcasted phases has been given. General regularities of formation of compounds with the ThCr2Si2 type crystalline structure have been discussed

  18. Crystal structures and magnetic properties of the BaAl4-type structure derivatives in Gd–Al–Ga system

    International Nuclear Information System (INIS)

    Highlights: •We study the crystal structure of GdAlxGa4?x compounds with 8–66 at.% Ga. •Existing range of these compounds is fragmented into seven individual regions. •The effective magnetic moments have been calculated. •The excess magnetic moments are caused by the contribution of the non-4f electrons. -- Abstract: The crystal structures of GdAlxGa4?x?v compounds (8–66 at.% Ga, x = 3.6–0.70, v = 0–0.12) were studied by the X-ray diffraction methods (both single crystal and powder diffraction ones). Two new types of structure (monoclinic GdAl3.00Ga0.76 and orthorhombic GdAl2Ga2) were shown to be constructed of two distorted BaAl4-like fragments. Reasoning from the peculiarities of crystal structures, the whole existence region of the GdAlxGa4?x?v compounds is fragmented into seven narrow individual ones (seven compounds). At the temperature range 300–650 K the GdAlxGa4?x?v alloys were shown to be paramagnets with magnetic moments decreasing from 8.07 to 7.84?B with Ga-content increasing

  19. Four basic symmetry types in the universal 7-cluster structure of 143 complete bacterial genomic sequences

    CERN Document Server

    Gorban, A N; Zinovyev, A Yu

    2011-01-01

    Coding information is the main source of heterogeneity (non-randomness) in the sequences of bacterial genomes. This information can be naturally modeled by analysing cluster structures in the "in-phase" triplet distributions of relatively short genomic fragments (200-400bp). We found a universal 7-cluster structure in bacterial genomic sequences and explained its properties. We show that codon usage of bacterial genomes is a multi-linear function of their genomic G+C-content with high accuracy. Based on the analysis of 143 completely sequenced bacterial genomes available in Genbank in August 2004, we show that there are four "pure" types of the 7-cluster structure observed. All 143 cluster animated 3D-scatters are collected in a database and is made available on our web-site: http://www.ihes.fr/~zinovyev/7clusters The finding can be readily introduced into any software for gene prediction, sequence alignment or bacterial genomes classification.

  20. Development of a new benzophenone-diketopiperazine-type potent antimicrotubule agent possessing a 2-pyridine structure.

    Science.gov (United States)

    Hayashi, Yoshiki; Takeno, Haruka; Chinen, Takumi; Muguruma, Kyohei; Okuyama, Kohei; Taguchi, Akihiro; Takayama, Kentaro; Yakushiji, Fumika; Miura, Masahiko; Usui, Takeo; Hayashi, Yoshio

    2014-10-01

    A new benzophenone-diketopiperazine-type potent antimicrotubule agent was developed by modifying the structure of the clinical candidate plinabulin (1). Although the right-hand imidazole ring with a branched alkyl chain at the 5-position in 1 was critical for the potency of the antimicrotubule activity, we successfully substituted this moiety with a simpler 2-pyridyl structure by converting the left-hand ring from a phenyl to a benzophenone structure without decreasing the potency. The resultant compound 6b (KPU-300) exhibited a potent cytotoxicity, with an IC50 value of 7.0 nM against HT-29 cells, by strongly binding to tubulin (K d = 1.3 ?M) and inducing microtubule depolymerization. PMID:25313318

  1. Observation of Current Structures at Type-III ELM Onset on EAST

    DEFF Research Database (Denmark)

    Yan, Ning; Naulin, Volker

    In far scrape-o layer (SOL), alternating negative and positive burst structures in ion saturation current were detected at the onset of each type-III edge localized mode (ELM) on EAST. Different from the fast streaming phenomenon reported previously, one subsequent positive burst structure appears every time in the early phase of ELM. It seems like a quick transitional stage between edge localized mode (MHD) phase and transport phase during the ELM. A pronounced sinusoidal pattern has been observed on the radial magnetic induction signal by Langmuir - magnetic probe, corresponding with almost a single peak mode on the poloidal induction signal in this transitional phase. As a local diagnostic, the floating potential arises abruptly in this phase, indicating the emergence or passage of polarized plasma structure. Further more, the ELM crash enter into another phase after this sudden burst structure. To verify the current characteristic of this structure, a mono-polar current filaments model was involved, which can reproduce same pattern commendably. Thus, current transport may dominant in transitional stage and plays an important role in the nonlinear development phase of ELM exhaustive crash. As current structure can only be observed in far SOL region of EAST, it maybe conceivable to consider the current origin from local condition rather than release from inside of the pedestal. Our observation may potentially provide support evidence for the recent theory prediction that the error led generated by scrape-off layer current can ultimately trigger the ELM through the coupling with MHD modes inside the separatrix.

  2. Pressure-induced phase transition of SmBi with a NaCl-type structure

    International Nuclear Information System (INIS)

    By use of synchrotron radiation, powder x-ray diffraction of SmBi with a NaCl-type structure has been studied up to 30 GPa at room temperature. A first-order phase transition began to occur at around 16.2 GPa. SmBi transformed from the NaCl-type (B1) to the tetragonal (distorted CsCl-type) structure with the volume collapse of about 8.2 % at around 18.3 GPa. Crystal data of the single phase are a = 3.775(5) A, c = 3.25 (2) A, c/a = 0.86 and V = 46.4 (3) A3 at 20.3 GPa. The high-pressure form of SmBi is isostructural with that of SmAs. A bulk modulus of SmBi was estimated from the volume vs. pressure curve fitted by a Birch equation of state. The bulk modulus (B0) and its pressure derivative (B0') are 68 ± 3 GPa and 3.9 ± 0.3, respectively. The transition pressure and the bulk modulus of SmBi are larger than those of CeBi and PrBi. The structural high-pressure behaviour for SmX (X = P, As, Sb and Bi) is discussed. The structural phase transition of LaBi and NdBi occurred at around 11.5 GPa and 16.8 GPa, respectively. The transition pressures of LnBi (Ln = La, Ce, Pr, Nd and Sm) decreased with increasing lattice constant.

  3. Superconductivity in Pseudo-Binary Silicide SrNixSi2-x with AlB2-Type Structure

    OpenAIRE

    Pyon, Sunseng; Kudo, Kazutaka; Nohara, Minoru

    2012-01-01

    We demonstrate the emergence of superconductivity in pseudo-binary silicide SrNixSi2-x. The compound exhibits a structural phase transition from the cubic SrSi2-type structure (P4132) to the hexagonal AlB2-type structure (P6/mmm) upon substituting Ni for Si at approximately x = 0.1. The hexagonal structure is stabilized in the range of 0.1 < x < 0.7. The superconducting phase appears in the vicinity of the structural phase boundary. Ni acts as a nonmagnetic dopant, as confir...

  4. Physcomitrella HMGA-type proteins display structural differences compared to their higher plant counterparts

    International Nuclear Information System (INIS)

    High mobility group (HMG) proteins of the HMGA family are chromatin-associated proteins that act as architectural factors in nucleoprotein structures involved in gene transcription. To date, HMGA-type proteins have been studied in various higher plant species, but not in lower plants. We have identified two HMGA-type proteins, HMGA1 and HMGA2, encoded in the genome of the moss model Physcomitrella patens. Compared to higher plant HMGA proteins, the two Physcomitrella proteins display some structural differences. Thus, the moss HMGA proteins have six (rather than four) AT-hook DNA-binding motifs and their N-terminal domain lacks similarity to linker histone H1. HMGA2 is expressed in moss protonema and it localises to the cell nucleus. Typical of HMGA proteins, HMGA2 interacts preferentially with A/T-rich DNA, when compared with G/C-rich DNA. In cotransformation assays in Physcomitrella protoplasts, HMGA2 stimulated reporter gene expression. In summary, our data show that functional HMGA-type proteins occur in Physcomitrella

  5. Thermoelectric properties and micro-structure characteristics of annealed N-type bismuth telluride thin film

    International Nuclear Information System (INIS)

    N-type bismuth telluride (Bi2Te3) thermoelectric thin films were deposited by co-sputtering simple substance Te and Bi targets. The deposited films were annealed under various temperatures. The composition ratio, micro-structure and thermoelectric properties of the prepared films were systematically investigated by energy dispersive spectrometer, X-ray diffraction, four-probe method and Seebeck coefficient measurement system. When the annealing temperature is 400 °C, the stoichiometric N-type Bi2Te3 film is achieved, which has a maximum thermoelectric power factor of 0.821 × 10?3 W m?1 K?2. Furthermore, the dependence of Seebeck coefficient, electrical conductivity and power factor of the stoichiometric N-type Bi2Te3 film annealed at film 400 °C on the applied temperature ranging from 25 °C to 315 °C was investigated. The results show that a highest power factor of 3.288 × 10?3 W m?1 K?2 is obtained at the applied temperature of 275 °C. The structural and thermoelectric properties of the deposited bismuth telluride thin films are greatly improved by annealing and the Seebeck coefficient, electrical conductivity and power factor increase with the applied temperature rising, which are helpful and could be guidance for preparing the high-performance thin film thermoelectric materials for thermoelectric application.

  6. Structural mechanism of C-type inactivation in K[superscript +] channels

    Energy Technology Data Exchange (ETDEWEB)

    Cuello, Luis G.; Jogini, Vishwanath; Cortes, D. Marien; Perozo, Eduardo (UC)

    2010-08-30

    Interconversion between conductive and non-conductive forms of the K{sup +} channel selectivity filter underlies a variety of gating events, from flicker transitions (at the microsecond timescale) to C-type inactivation (millisecond to second timescale). Here we report the crystal structure of the Streptomyces lividans K{sup +} channel KcsA in its open-inactivated conformation and investigate the mechanism of C-type inactivation gating at the selectivity filter from channels 'trapped' in a series of partially open conformations. Five conformer classes were identified with openings ranging from 12 {angstrom} in closed KcsA (C{alpha}-C{alpha} distances at Thr112) to 32 {angstrom} when fully open. They revealed a remarkable correlation between the degree of gate opening and the conformation and ion occupancy of the selectivity filter. We show that a gradual filter backbone reorientation leads first to a loss of the S2 ion binding site and a subsequent loss of the S3 binding site, presumably abrogating ion conduction. These structures indicate a molecular basis for C-type inactivation in K{sup +} channels.

  7. Structure and order in CoPt-type nanoalloys: From thin films to supported clusters

    Science.gov (United States)

    Andreazza, Pascal; Pierron-Bohnes, Véronique; Tournus, Florent; Andreazza-Vignolle, Caroline; Dupuis, Véronique

    2015-06-01

    Among nanoalloys, Co-Pt type (CoPt or FePt) supported nanostructures are very interesting systems due to the direct link between atom arrangement and magnetic behavior. In addition, these alloys become model systems in the field of nanoalloys, due to the diversity of atom arrangements either present in the bulk state or specific to the nanoscale (chemically ordered L10, L12, or disordered fcc structures, core-shell, five-fold structures - icosahedral or decahedral, etc.). The synergy between experimental and modeling efforts has allowed the emergence of an overview of the structural, morphological and chemical behaviors of CoPt-based supported nanoparticles in terms of phase diagrams (temperature, composition, size effect), kinetic behavior (growth, annealing, ordering), and also in terms of environment effects (substrate, capping, matrix, gas) and of magnetic properties. All aspects of this complexity are reviewed: synthesis strategies (physical deposition, cluster beam deposition and wet chemical methods), magnetic behavior (atomic magnetic moment, magnetic anisotropy energy), structural transitions (non-crystalline/crystalline structures, order/disorder, surface/interface segregation), etc. In this field, the investigation techniques, such as electron microscopy and X-ray scattering or absorption techniques, are generally used at their ultimate limit due the small size of the studied objects. Finally, several aspects of the annealing process, which is a key phenomenon to achieve the chemical order, have been discussed in both thermodynamic and kinetic points of view (size effect, critical temperature, annealing time, twinning, coalescence, etc.).

  8. Refined solution structure of a liganded type 2 wheat nonspecific lipid transfer protein.

    Science.gov (United States)

    Pons, Jean-Luc; de Lamotte, Frédéric; Gautier, Marie-Françoise; Delsuc, Marc-André

    2003-04-18

    The refined structure of a wheat type 2 nonspecific lipid transfer protein (ns-LTP2) liganded with l-alpha-palmitoylphosphatidylglycerol has been determined by NMR. The (15)N-labeled protein was produced in Pichia pastoris. Physicochemical conditions and ligandation were intensively screened to obtain the best NMR spectra quality. This ns-LTP2 is a 67-residue globular protein with a diameter of about 30 A. The structure is composed of five helices forming a right superhelix. The protein presents an inner cavity, which has been measured at 341 A(3). All of the helices display hydrophobic side chains oriented toward the cavity. The phospholipid is found in this cavity. Its fatty acid chain is completely inserted in the protein, the l-alpha-palmitoylphosphatidylglycerol glycerol moiety being located on a positively charged pocket on the surface of the protein. The superhelix structure of the protein is coiled around the fatty acid chain. The overall structure shows similarities with ns-LTP1. Nevertheless, large three-dimensional structural discrepancies are observed for the H3 and H4 alpha-helices, the C-terminal region, and the last turn of the H2 helix. The lipid is orthogonal to the orientation observed in ns-LTP1. The volume of the hydrophobic cavity appears to be in the same range as the one of ns-LTP1, despite the fact that ns-LTP2 is shorter by 24 residues. PMID:12525478

  9. The electronic structure of zircon-type orthovanadates: Effects of high-pressure and cation substitution

    CERN Document Server

    Panchal, V; Segura, A; Rodriguez-Hernandez, P; Munoz, A; Lopez-Moreno, S; Bettinelli, M; 10.1063/1.3626060

    2012-01-01

    The electronic structure of four ternary-metal oxides containing isolated vanadate ions is studied. Zircon-type YVO4, YbVO4, LuVO4, and NdVO4 are investigated by high-pressure optical-absorption measurements up to 20 GPa. First-principles calculations based on density-functional theory were also performed to analyze the electronic band structure as a function of pressure. The electronic structure near the Fermi level originates largely from molecular orbitals of the vanadate ion, but cation substitution influence these electronic states. The studied ortovanadates, with the exception of NdVO4, undergo a zircon-scheelite structural phase transition that causes a collapse of the band-gap energy. The pressure coefficient dEg/dP show positive values for the zircon phase and negative values for the scheelite phase. NdVO4 undergoes a zircon-monazite-scheelite structural sequence with two associated band-gap collapses.

  10. Crystal structure of alluaudite-type Na4Co(MoO4)3

    Science.gov (United States)

    Nasri, Rawia; Fakhar Bourguiba, Noura; Zid, Mohamed Faouzi; Driss, Ahmed

    2014-01-01

    The title compound, tetra­sodium cobalt(II) tris­[molyb­date(IV)], was prepared by solid-state reactions. The structure is isotypic with Na3In2(AsO4)3 and Na3In2(PO4)3. The main structural feature is the presence of infinite chains of edge-sharing X 2O10 (X = Co/Na) dimers, which are linked by MoO4 tetra­hedra, forming a three-dimensional framework enclosing two types of hexa­gonal tunnels in which Na+ cations reside. In this alluaudite structure, Co and Na atoms are located at the same general site with occupancies of 0.503?(5) and 0.497?(6), respectively. The other three Na and one of the two Mo atoms lie on special positions (site symmetries 2, -1, 2 and 2, respectively). The structure is compared with similar structures and other members of alluaudite family. PMID:25309171

  11. Crystal Structure of Hcp from Acinetobacter baumannii: A Component of the Type VI Secretion System

    Science.gov (United States)

    Ruiz, Federico M.; Santillana, Elena; Spínola-Amilibia, Mercedes; Torreira, Eva; Culebras, Esther; Romero, Antonio

    2015-01-01

    The type VI secretion system (T6SS) is a bacterial macromolecular machine widely distributed in Gram-negative bacteria, which transports effector proteins into eukaryotic host cells or other bacteria. Membrane complexes and a central tubular structure, which resembles the tail of contractile bacteriophages, compose the T6SS. One of the proteins forming this tube is the hemolysin co-regulated protein (Hcp), which acts as virulence factor, as transporter of effectors and as a chaperone. In this study, we present the structure of Hcp from Acinetobacter baumannii, together with functional and oligomerization studies. The structure of this protein exhibits a tight ? barrel formed by two ? sheets and flanked at one side by a short ?-helix. Six Hcp molecules associate to form a donut-shaped hexamer, as observed in both the crystal structure and solution. These results emphasize the importance of this oligomerization state in this family of proteins, despite the low similarity of sequence among them. The structure presented in this study is the first one for a protein forming part of a functional T6SS from A. baumannii. These results will help us to understand the mechanism and function of this secretion system in this opportunistic nosocomial pathogen. PMID:26079269

  12. A Salmonella type three secretion effector/chaperone complex adopts a hexameric ring-like structure.

    Science.gov (United States)

    Roblin, Pierre; Dewitte, Frédérique; Villeret, Vincent; Biondi, Emanuele G; Bompard, Coralie

    2015-02-15

    Many bacterial pathogens use type three secretion systems (T3SS) to inject virulence factors, named effectors, directly into the cytoplasm of target eukaryotic cells. Most of the T3SS components are conserved among plant and animal pathogens, suggesting a common mechanism of recognition and secretion of effectors. However, no common motif has yet been identified for effectors allowing T3SS recognition. In this work, we performed a biochemical and structural characterization of the Salmonella SopB/SigE chaperone/effector complex by small-angle X-ray scattering (SAXS). Our results showed that the SopB/SigE complex is assembled in dynamic homohexameric-ring-shaped structures with an internal tunnel. In this ring, the chaperone maintains a disordered N-terminal end of SopB molecules, in a good position to be reached and processed by the T3SS. This ring dimensionally fits the ring-organized molecules of the injectisome, including ATPase hexameric rings; this organization suggests that this structural feature is important for ATPase recognition by T3SS. Our work constitutes the first evidence of the oligomerization of an effector, analogous to the organization of the secretion machinery, obtained in solution. As effectors share neither sequence nor structural identity, the quaternary oligomeric structure could constitute a strategy evolved to promote the specificity and efficiency of T3SS recognition. PMID:25404693

  13. Structure of a human monoclonal antibody Fab fragment against gp41 of human immunodeficiency virus type

    Science.gov (United States)

    He, X. M.; Ruker, F.; Casale, E.; Carter, D. C.

    1992-01-01

    The three-dimensional structure of a human monoclonal antibody (Fab), which binds specifically to a major epitope of the transmembrane protein gp41 of the human immunodeficiency virus type 1, has been determined by crystallographic methods to a resolution of 2.7 A. It has been previously determined that this antibody recognizes the epitope SGKLICTTAVPWNAS, belongs to the subclass IgG1 (kappa), and exhibits antibody-dependent cellular cytotoxicity. The quaternary structure of the Fab is in an extended conformation with an elbow bend angle between the constant and variable domains of 175 degrees. Structurally, four of the hypervariable loops can be classified according to previously recognized canonical structures. The third hypervariable loops of the heavy (H3) and light chain (L3) are structurally distinct. Hypervariable loop H3, residues 102H-109H, is unusually extended from the surface. The complementarity-determining region forms a hydrophobic binding pocket that is created primarily from hypervariable loops L3, H3, and H2.

  14. Structural and bioinformatic characterization of an Acinetobacter baumannii type II carrier protein

    International Nuclear Information System (INIS)

    The high-resolution crystal structure of a free-standing carrier protein from Acinetobacter baumannii that belongs to a larger NRPS-containing operon, encoded by the ABBFA-003406–ABBFA-003399 genes of A. baumannii strain AB307-0294, that has been implicated in A. baumannii motility, quorum sensing and biofilm formation, is presented. Microorganisms produce a variety of natural products via secondary metabolic biosynthetic pathways. Two of these types of synthetic systems, the nonribosomal peptide synthetases (NRPSs) and polyketide synthases (PKSs), use large modular enzymes containing multiple catalytic domains in a single protein. These multidomain enzymes use an integrated carrier protein domain to transport the growing, covalently bound natural product to the neighboring catalytic domains for each step in the synthesis. Interestingly, some PKS and NRPS clusters contain free-standing domains that interact intermolecularly with other proteins. Being expressed outside the architecture of a multi-domain protein, these so-called type II proteins present challenges to understand the precise role they play. Additional structures of individual and multi-domain components of the NRPS enzymes will therefore provide a better understanding of the features that govern the domain interactions in these interesting enzyme systems. The high-resolution crystal structure of a free-standing carrier protein from Acinetobacter baumannii that belongs to a larger NRPS-containing operon, encoded by the ABBFA-003406–ABBFA-003399 genes of A. baumannii strain AB307-0294, that has been implicated in A. baumannii motility, quorum sensing and biofilm formation, is presented here. Comparison with the closest structural homologs of other carrier proteins identifies the requirements for a conserved glycine residue and additional important sequence and structural requirements within the regions that interact with partner proteins

  15. From Proteomics to Structural Studies of Cytosolic/Mitochondrial-Type Thioredoxin Systems in Barley Seeds

    DEFF Research Database (Denmark)

    Shahpiri, Azar; Svensson, Birte

    2009-01-01

    Thioredoxins (Trx) are ubiquitous proteins that participate in thiol disulfide reactions via two active site cysteine residues, allowing Trx to reduce disulfide bonds in target proteins. Recent progress in proteome analysis has resulted in identification of a wide range of potential target proteins for Trx, indicating that Trx plays a key role in several aspects of cell metabolism. In contrast to other organisms, plants contain multiple forms of Trx that are classified based on their primary structures and sub-cellular localization. The reduction of cytosolic and mitochondrial types of Trx is dependent on NADPH and catalyzed by NADPH-dependent thioredoxin reductase (NTR). In barley, two isoforms each of Trx and NTR have been identified and investigated using proteomics, gene expression, and structural studies. This review outlines the diverse roles suggested for cytosolic/mitochondrial-type Trx systems in cereal seeds and summarizes the current knowledge of the barley system including recent data on function,regulation, interactions, and structure. Directions for future research are discussed.

  16. Synthesis, crystal structures, and luminescent properties of two types of lanthanide phosphonates

    International Nuclear Information System (INIS)

    Hydrothermal reactions of different lanthanide(III) salts with an amino-diphosphonate ligand (H4L=C6H5CH2N(CH2PO3H2)2) led to two series of lanthanide phosphonates, namely, Ln(H2L)(H3L) (Ln=La, 1; Pr, 2; Nd, 3; Sm, 4; Eu, 5; Gd, 6; Tb, 7). Compounds 1-5 feature a one-dimensional (1D) chain structure in which dimers of two edge-sharing LnO8 polyhedra are interconnected by bridging phosphonate groups, such 1D arrays are further interlinked via strong hydrogen bonds between non-coordinated phosphonate oxygen atoms into a two-dimensional (2D) layer with the phenyl groups of the ligands orientated toward the interlayer space. Compounds 6 and 7 also show a different 1D array in which the LnO6 octahedra are bridged by phosphonate groups via corner-sharing, such chains are also further interlinked by hydrogen bonds into a 2D supramolecular layer. Compounds 5 and 7 emit red and green light with a lifetime of 2.1 and 3.7 ms, respectively. - Graphic abstract: Two series of luminescent lanthanide phosphonates have been synthesized and structurally characterized. Their structures feature two different types of 2D sumpramolecular layers based on two types of 1D arrays interlinked via strong hydrogen bonds

  17. DG-FEM solution for nonlinear wave-structure interaction using Boussinesq-type equations

    DEFF Research Database (Denmark)

    Engsig-Karup, Allan Peter; Hesthaven, Jan

    2008-01-01

    We present a high-order nodal Discontinuous Galerkin Finite Element Method (DG-FEM) solution based on a set of highly accurate Boussinesq-type equations for solving general water-wave problems in complex geometries. A nodal DG-FEM is used for the spatial discretization to solve the Boussinesq equations in complex and curvilinear geometries which amends the application range of previous numerical models that have been based on structured Cartesian grids. The Boussinesq method provides the basis for the accurate description of fully nonlinear and dispersive water waves in both shallow and deep waters within the breaking limit. To demonstrate the current applicability of the model both linear and mildly nonlinear test cases are considered in two horizontal dimensions where the water waves interact with bottom-mounted fully reflecting structures. It is established that, by simple symmetry considerations combined with a mirror principle, it is possible to impose weak slip boundary conditions for both structured and general curvilinear wall boundaries while maintaining the accuracy of the scheme. As is standard for current high-order Boussinesq-type models, arbitrary waves can be generated and absorbed in the interior of the computational domain using a flexible relaxation technique applied on the free surface variables.

  18. Crystal structure of a novel cysteinless plant Kunitz-type protease inhibitor

    International Nuclear Information System (INIS)

    Bauhinia bauhinioides Cruzipain Inhibitor (BbCI) is a cysteine protease inhibitor highly homologous to plant Kunitz-type inhibitors. However, in contrast to classical Kunitz family inhibitors it lacks cysteine residues and therefore disulfide bridges. BbCI is also distinct in the ability to inactivate enzymes belonging to two different classes, cysteine and serine proteases. Besides inhibiting the cysteine protease cruzipain, BbCI also inhibits cathepsin L and the serine proteases HNE (human neutrophil elastase) and PPE (porcine pancreatic elastase). Monoclinic crystals of the recombinant inhibitor that diffract to 1.7 A resolution were obtained using hanging drop method by vapor diffusion at 18 oC. The refined structure shows the conservative ?-trefoil fold features of the Kunitz inhibitors. In BbCI, one of the two characteristic S-S bonds is replaced by the water-mediated interaction between Tyr125 and Gly132. In this work we explore the structural differences between Kunitz-type inhibitors and analyze the essential interactions that maintain the protein structural stability preserving its biological function

  19. Structural and electronic properties of type-I and type-VIII Ba{sub 8}Ga{sub 16}Sn{sub 30} clathrates under compression

    Energy Technology Data Exchange (ETDEWEB)

    Li, D.C. [Department of Applied Physics, Chongqing University, Chongqing 400044 (China); Fang, L., E-mail: fangliangcqu@yahoo.com.cn [Department of Applied Physics, Chongqing University, Chongqing 400044 (China); Deng, S.K.; Kang, K.Y.; Shen, L.X. [Education Ministry Key Laboratory of Renewable Energy Advanced Materials and Manufacturing Technology, Yunnan Normal University, Kunming, Yunnan Province, 650092 (China); Wei, W.H.; Ruan, H.B. [Department of Applied Physics, Chongqing University, Chongqing 400044 (China)

    2012-04-15

    The total energy and electronic structures for type-I ({beta} phase) and type-VIII ({alpha} phase) Ba{sub 8}Ga{sub 16}Sn{sub 30} clathrates under hydrostatic pressure have been investigated using density functional theory (DFT) calculations. It was found that the type-VIII phase is more stable than the type-I one at ambient conditions and that {beta}{yields}{alpha} phase transition can not occur under hydrostatic pressure. The band structures show that the type-I and type-VIII Ba{sub 8}Ga{sub 16}Sn{sub 30} are indirect semiconductors with band gaps of 0.24 eV and 0.19 eV, respectively. The results suggested that type-I clathrate Ba{sub 8}Ga{sub 16}Sn{sub 30} has a larger value of the thermoelectric (TE) power than that of type-VIII clathrate. We found that pressure tuning changes the k-point of conduction band minimum (CBM) in the Brillouin zone for {beta}-phase, but it is not the case for {alpha}-phase. Furthermore, the results show that the pressure can change the interaction between guest atoms and the host lattice, and consequently results in the decrease of the band gap of {beta}-phase and the increase of the band gap of {alpha}-phase, indicating that the pressure effect can play an important role in the magnitude of the TE power.

  20. DYNAMICS AND CLASSIFICATION OF THE TYPES OF BUSINESS STRUCTURES IN CONSTRUCTION

    Directory of Open Access Journals (Sweden)

    Alexander Aleksandrovich Halin

    2015-03-01

    Full Text Available Entrepreneurs need information about a possible organizational and species diversity of enterprise structures, on the specific characteristics associated with each of their mind, about the advantages and disadvantages of multilevel business. To do this, society must be scientifically based unified classification of business structures. However, at present there is no such classification. In modern economic literature highlights only some aspects of group business structures, including construction.The most important classification features allow revealing the essential characteristics of business organizations in general, and in the construction sector of the economy, in particular. These characteristics should include: stakeholders and shape its organizational and legal reference; limits the liability of owners; form and subject of his own; nature of the control of the owner of capital resources; the involvement of stakeholders in the property; form of participation in the activities of the owner of the capital; level of implementation of the interests of the owners; type, legal status and the main objective of the enterprise structure; the use of hired labor.In 2013, in the construction industry of Russia operated 218, 0 thousand business structures, which functioned mainly on the basis of private ownership. The growth trend in the number of business organizations, which occurred during the period 2000-2013 years, characterized by overt instability. State socio-economic policy, the level of competition, structural changes in the economy, changes in production technologies, the mobility of funding, a way of doing construction work are the main factors that influence the dynamics of business structures in construction.

  1. Thermoelectric and transport properties of sintered n-type K8Ba16Ga40Sn96 with type-II clathrate structure

    International Nuclear Information System (INIS)

    This clathrate had a maximum dimensionless figure-of-merit, ZT, of 0.93 at 637?K, which was slightly higher than that of 0.83 for the sintered type-VIII clathrate Ba8Ga16Sn30. We investigated the high-temperature thermoelectric properties, transport properties, electronic structures, and thermal stabilities of the clathrates. The type-II clathrate was found to be superior to the type-VIII clathrate as a thermoelectric material; it had a high thermal stability and melting point, 859?K, high mobility, 141 cm2V?1s?1 at 300?K, because of its low inertial mass, and low high-temperature lattice thermal conductivity, approximately 4 mW cm?1K?1, resulting from a larger unit cell and weaker bipolar thermal conduction. We discuss these properties in terms of the electronic structure and the differences between the two types of clathrate.

  2. Thermoelectric and transport properties of sintered n-type K8Ba16Ga40Sn96 with type-II clathrate structure

    Science.gov (United States)

    Koda, Shota; Kishimoto, Kengo; Akai, Koji; Asada, Hironori; Koyanagi, Tsuyoshi

    2014-07-01

    This clathrate had a maximum dimensionless figure-of-merit, ZT, of 0.93 at 637 K, which was slightly higher than that of 0.83 for the sintered type-VIII clathrate Ba8Ga16Sn30. We investigated the high-temperature thermoelectric properties, transport properties, electronic structures, and thermal stabilities of the clathrates. The type-II clathrate was found to be superior to the type-VIII clathrate as a thermoelectric material; it had a high thermal stability and melting point, 859 K, high mobility, 141 cm2V-1s-1 at 300 K, because of its low inertial mass, and low high-temperature lattice thermal conductivity, approximately 4 mW cm-1K-1, resulting from a larger unit cell and weaker bipolar thermal conduction. We discuss these properties in terms of the electronic structure and the differences between the two types of clathrate.

  3. The structure of a lipid-water lamellar phase containing two types of lipid monolayers

    International Nuclear Information System (INIS)

    One lamellar phase, observed in the mitochondrial lipids-water system at low temperature (ca 253 K) and at low water content (ca 15%), contains four lipid monolayers in its unit cell, two of type ? and two of type ?. Previous X-ray scattering studies of this phase led to an ambiguity: the phase could contain either two homogeneous bilayers, one ? and one ?, or two mixed bilayers, each formed by an ? and a ? monolayer. A solution to this problem was sought in a neutron scattering study as a function of the D2O/H2O ratio. Because of limited resolution, straightforward analysis of the neutron scattering data leads also to ambiguous results. Using a more sophisticated analysis based upon the zeroth- and second-order moments of the Patterson peaks relevant to the exchangeable components, it is shown that the weight of the evidence is in favour of a structure containing mixed bilayers. (Auth.)

  4. Flat structure for the simple elliptic singularity of type $\\widetilde {\\bf E_6}$ and Jacobi form

    CERN Document Server

    Satake, I

    1993-01-01

    In order to construct the inverse mapping of the period mapping for the primitive form for the semi-universal deformation of a simple elliptic singularity, K.Saito introduced in [5] the ``flat structure'' for the extended affine root system. In section 3, we construct explicitly the flat theta invariants in the case of type $E_6$ using the Jacobi form introduced by Wirthm\\"uller [7]. Combining the results of Kato [3], Noumi [4] (explicit description of the flat coordinates), this gives an answer to Jacobi's inversion problem (up to linear isomorphism) of this period mapping for a simple elliptic singularity of type $\\tilde E_6$ (see also [6]). The details will be published elsewhere.

  5. Optimal design of a spectral readout type planar waveguide-mode sensor with a monolithic structure.

    Science.gov (United States)

    Wang, Xiaomin; Fujimaki, Makoto; Kato, Takafumi; Nomura, Ken-Ichi; Awazu, Koichi; Ohki, Yoshimichi

    2011-10-10

    Optical planar waveguide-mode sensor is a promising candidate for highly sensitive biosensing techniques in fields such as protein adsorption, receptor-ligand interaction and surface bacteria adhesion. To make the waveguide-mode sensor system more realistic, a spectral readout type waveguide sensor is proposed to take advantage of its high speed, compactness and low cost. Based on our previously proposed monolithic waveguide-mode sensor composed of a SiO2 waveguide layer and a single crystalline Si layer [1], the mechanism for achieving high sensitivity is revealed by numerical simulations. The optimal achievable sensitivities for a series of waveguide structures are summarized in a contour map, and they are found to be better than those of previously reported angle-scan type waveguide sensors. PMID:21997031

  6. Direct metal micropatterning on needle-type structures towards bioimpedance and chemical sensing applications

    Science.gov (United States)

    Kim, Sanghyeok; Park, Jae-ho; Kang, Kyungnam; Park, Chong-Ook; Park, Inkyu

    2015-01-01

    Direct metal patterning methods, such as screen printing, inkjet printing and gravure/flexography printing, are widely used to form electrodes or interconnections for printed electronic devices due to their inexpensive, simple and rapid fabrication as compared to vacuum-based conventional metallization processes. Here, we present direct metal patterning by modified screen printing on the curved surface of needle-type rod structures (i.e. rods with radius of ? control of a light emission diode (LED) as well as the real-time electrochemical impedance spectroscopy of electrolyte solutions and solid objects by the rod insertion. Furthermore, needles with multiple pairs of microelectrodes were used to measure the electrical impedance of biological samples such as fat and muscle tissues of porcine meat. In addition, a needle-type probe sensor with gas sensing capability was demonstrated by using a needle with printed Ag electrodes and Pd thin films.

  7. Structural Characterization of Lignin in Wild-type versus COMT Down-regulated Switchgrass

    Directory of Open Access Journals (Sweden)

    ArthurRagauskas

    2014-01-01

    Full Text Available This study examined the chemical structural characteristics of cellulolytic enzyme lignin isolated from switchgrass focusing on comparisons between wild-type control and caffeic acid 3-O-methyltransferase (COMT down-regulated transgenic line. Nuclear magnetic resonance (NMR techniques including 13C, 31P, and two-dimensional 13C-1H heteronuclear single quantum coherence (HSQC as well as gel permeation chromatography (GPC were employed. Compared to the wild-type, the COMT down-regulated transgenic switchgrass lignin demonstrated a decrease in syringyl (S: guaiacyl (G ratio and p-coumarate:ferulate ratio, an increase in relative abundance of phenylcoumaran unit, and a comparable content of total free phenolic OH groups along with formation of benzodioxane unit. In addition, COMT down-regulation had no significant effects on the lignin molecular weights during its biosynthesis process.

  8. Recovering the Dynamical Structure and Formation History of Early-Type Galaxies

    Science.gov (United States)

    Tsatsi, Athanasia; van de Ven, Glenn; Macciò, Andrea V.

    2015-01-01

    Many early-type galaxies show clear signatures of non-axisymmetry in their photometry, as well as in their kinematics. A general technique to model those triaxial systems is provided by Schwarzschild's (1979) numerical orbit superposition method, which is implemented in triaxial geometry (van den Bosch et al. 2008, 2009, van de Ven et al. 2008). We have constructed Triaxial Schwarzschild models for simulated elliptical-like merger remnant galaxies. The total mass distribution and orbital structure derived from these models are confronted with the real distribution of the simulated galaxies. The results of this comparison can help towards understanding how well one can recover the real orbital and mass distribution of early-type galaxies, as well as to constrain their formation history, using orbit-based dynamical modeling.

  9. Impact of model structure and parameterization on Penman-Monteith type evaporation models

    KAUST Repository

    Ershadi, A.

    2015-04-12

    The impact of model structure and parameterization on the estimation of evaporation is investigated across a range of Penman-Monteith type models. To examine the role of model structure on flux retrievals, three different retrieval schemes are compared. The schemes include a traditional single-source Penman-Monteith model (Monteith, 1965), a two-layer model based on Shuttleworth and Wallace (1985) and a three-source model based on Mu et al. (2011). To assess the impact of parameterization choice on model performance, a number of commonly used formulations for aerodynamic and surface resistances were substituted into the different formulations. Model response to these changes was evaluated against data from twenty globally distributed FLUXNET towers, representing a cross-section of biomes that include grassland, cropland, shrubland, evergreen needleleaf forest and deciduous broadleaf forest. Scenarios based on 14 different combinations of model structure and parameterization were ranked based on their mean value of Nash-Sutcliffe Efficiency. Results illustrated considerable variability in model performance both within and between biome types. Indeed, no single model consistently outperformed any other when considered across all biomes. For instance, in grassland and shrubland sites, the single-source Penman-Monteith model performed the best. In croplands it was the three-source Mu model, while for evergreen needleleaf and deciduous broadleaf forests, the Shuttleworth-Wallace model rated highest. Interestingly, these top ranked scenarios all shared the simple lookup-table based surface resistance parameterization of Mu et al. (2011), while a more complex Jarvis multiplicative method for surface resistance produced lower ranked simulations. The highly ranked scenarios mostly employed a version of the Thom (1975) formulation for aerodynamic resistance that incorporated dynamic values of roughness parameters. This was true for all cases except over deciduous broadleaf sites, where the simpler aerodynamic resistance approach of Mu et al. (2011) showed improved performance. Overall, the results illustrate the sensitivity of Penman-Monteith type models to model structure, parameterization choice and biome type. A particular challenge in flux estimation relates to developing robust and broadly applicable model formulations. With many choices available for use, providing guidance on the most appropriate scheme to employ is required to advance approaches for routine global scale flux estimates, undertake hydrometeorological assessments or develop hydrological forecasting tools, amongst many other applications. In such cases, a multi-model ensemble or biome-specific tiled evaporation product may be an appropriate solution, given the inherent variability in model and parameterization choice that is observed within single product estimates.

  10. Impact of model structure and parameterization on Penman-Monteith type evaporation models

    Science.gov (United States)

    Ershadi, A.; McCabe, M. F.; Evans, J. P.; Wood, E. F.

    2015-06-01

    The impact of model structure and parameterization on the estimation of evaporation is investigated across a range of Penman-Monteith type models. To examine the role of model structure on flux retrievals, three different retrieval schemes are compared. The schemes include a traditional single-source Penman-Monteith model (Monteith, 1965), a two-layer model based on Shuttleworth and Wallace (1985) and a three-source model based on Mu et al. (2011). To assess the impact of parameterization choice on model performance, a number of commonly used formulations for aerodynamic and surface resistances were substituted into the different formulations. Model response to these changes was evaluated against data from twenty globally distributed FLUXNET towers, representing a cross-section of biomes that include grassland, cropland, shrubland, evergreen needleleaf forest and deciduous broadleaf forest. Scenarios based on 14 different combinations of model structure and parameterization were ranked based on their mean value of Nash-Sutcliffe Efficiency. Results illustrated considerable variability in model performance both within and between biome types. Indeed, no single model consistently outperformed any other when considered across all biomes. For instance, in grassland and shrubland sites, the single-source Penman-Monteith model performed the best. In croplands it was the three-source Mu model, while for evergreen needleleaf and deciduous broadleaf forests, the Shuttleworth-Wallace model rated highest. Interestingly, these top ranked scenarios all shared the simple lookup-table based surface resistance parameterization of Mu et al. (2011), while a more complex Jarvis multiplicative method for surface resistance produced lower ranked simulations. The highly ranked scenarios mostly employed a version of the Thom (1975) formulation for aerodynamic resistance that incorporated dynamic values of roughness parameters. This was true for all cases except over deciduous broadleaf sites, where the simpler aerodynamic resistance approach of Mu et al. (2011) showed improved performance. Overall, the results illustrate the sensitivity of Penman-Monteith type models to model structure, parameterization choice and biome type. A particular challenge in flux estimation relates to developing robust and broadly applicable model formulations. With many choices available for use, providing guidance on the most appropriate scheme to employ is required to advance approaches for routine global scale flux estimates, undertake hydrometeorological assessments or develop hydrological forecasting tools, among many other applications. In such cases, a multi-model ensemble or biome-specific tiled evaporation product may be an appropriate solution, given the inherent variability in model and parameterization choice that is observed within single product estimates.

  11. Quasiparticle band structures and thermoelectric transport properties of p-type SnSe

    OpenAIRE

    Shi, Guangsha; Kioupakis, Emmanouil

    2014-01-01

    We used density functional and many-body perturbation theory to calculate the quasiparticle band structures and electronic transport parameters of p-type SnSe both for the low-temperature Pnma and high-temperature Cmcm phases. The Pnma phase has an indirect band gap of 0.829 eV while the Cmcm has a direct band gap of 0.464 eV. Both phases exhibit multiple local band extrema within an energy range comparable to the thermal energy of carriers from the global extrema. We calcul...

  12. A note on the prolongation structure of the cubically nonlinear integrable Camassa-Holm type equation

    International Nuclear Information System (INIS)

    In this Letter, we formulate an exterior differential system for the newly discovered cubically nonlinear integrable Camassa-Holm type equation. From the exterior differential system we establish the integrability of this equation. We then study Cartan prolongation structure of this equation. We also discuss the method of identifying conservation laws and Baecklund transformation for this equation from the identified exterior differential system. -- Highlights: ? An exterior differential system for a cubic nonlinear integrable equation is given. ? The conservation laws from the exterior differential system is derived. ? The Baecklund transformation from the Cartan-Ehresmann connection is obtained.

  13. A note on the prolongation structure of the cubically nonlinear integrable Camassa-Holm type equation

    Energy Technology Data Exchange (ETDEWEB)

    Stalin, S. [Centre for Nonlinear Dynamics, School of Physics, Bharathidasan University, Tiruchirappalli 620024, Tamil Nadu (India); Senthilvelan, M., E-mail: velan@cnld.bdu.ac.in [Centre for Nonlinear Dynamics, School of Physics, Bharathidasan University, Tiruchirappalli 620024, Tamil Nadu (India)

    2011-10-17

    In this Letter, we formulate an exterior differential system for the newly discovered cubically nonlinear integrable Camassa-Holm type equation. From the exterior differential system we establish the integrability of this equation. We then study Cartan prolongation structure of this equation. We also discuss the method of identifying conservation laws and Baecklund transformation for this equation from the identified exterior differential system. -- Highlights: ? An exterior differential system for a cubic nonlinear integrable equation is given. ? The conservation laws from the exterior differential system is derived. ? The Baecklund transformation from the Cartan-Ehresmann connection is obtained.

  14. NEAR-EDGE STRUCTURE OF OXYGEN IN INORGANIC OXIDES : EFFECT OF LOCAL GEOMETRY AND CATION TYPE

    OpenAIRE

    Brown, G.; Waychunas, G.; Stohr, J.; Sette, F.

    1986-01-01

    NEXAFS measurements at the oxygen K-edge have been carried out on a variety of crystalline oxide samples to examine the effects of differences in local coordination environment of oxygen on near-edge structure. All spectra display an intense white line at about 543 eV and a strong shape resonance about 20 eV above the edge. The white line shifts to higher energies with increasing oxygen coordination number, although differences in nearest-neighbor type can affect this correlation. In addition...

  15. Structure of the Tandem Fibronectin Type 3 Domains of Neural Cell Adhesion Molecule

    OpenAIRE

    Carafoli, Federico; Saffell, Jane L.; Hohenester, Erhard

    2008-01-01

    Activation of the fibroblast growth factor receptor (FGFR) by neural cell adhesion molecule (NCAM) is essential for NCAM-mediated neurite outgrowth. Previous peptide studies have identified two regions in the fibronectin type 3 (FN3)-like domains of NCAM as being important for these activities. Here we report the crystal structure of the NCAM FN3 domain tandem, which reveals an acutely bent domain arrangement. Mutation of a non-conserved surface residue (M610R) led to a second crystal form sh...

  16. On the flat spacetime Galileons and the Born-Infeld type structures

    CERN Document Server

    Campuzano, Cuauhtemoc; Cruz, Miguel; Rojas, Efrain

    2015-01-01

    We show how the flat spacetime Galileon field theories in arbitrary dimensions can be obtained through a Born-Infeld type structure. This construction involves a brane metric and non-linear combinations of derivatives of a scalar field. Our setup gives rise to some Galileon tensors and vectors useful for the variational analysis which are related to the momentum density of the probe Lovelock branes floating in a $N$-dimensional flat bulk. We find further that the Noether currents associated to these Galileon theories may be written in terms of such tensors.

  17. Structure design and optimization of a new type of subsea pipeline connector

    Science.gov (United States)

    Hu, Xiaoming; Wang, Liquan; Liu, Yong; Ge, Rubo; Tan, Lei; Fu, Chuangye; Wei, Zongliang

    2012-03-01

    The basic configuration of a new type of subsea pipeline connector was proposed based on the press-fitting principle, and a parametric finite element model was created using APDL language in ANSYS. Combining the finite element model and optimization technology, the dimension optimization aiming at obtaining the minimum loading force and the optimum sealing performance was designed by the zero order optimization method. Experiments of the optimized connector were carried out. The results indicate that the optimum structural design significantly improved the indicators of the minimum loading force and sealing performance of the connector.

  18. Structure of branches in infrared-active fundamental-type bands of spherical-top molecules

    International Nuclear Information System (INIS)

    In the absence of strong accidental resonance, the detailed energy-level structures of all Q branches of infrared-active fundamental-type bands in spherical-top molecules are prescribed, in the first approximation, by the value of the single parameter, ? = ?/g, where ? = ?B/sub eff/sup Q/ and g is the tetrahedral or octahedral splitting constant. The Q branches of several heavy and light spherical tops are examined in this context, using energy-level diagrams, level cluster analysis, and computer graphics to simulate the superpositions of hundreds of absorption lines

  19. Structural basis of asymmetry in the human immunodeficiency virus type 1 reverse transcriptase heterodimer.

    OpenAIRE

    Wang, J.; Smerdon, S. J.; Ja?ger, J.; Kohlstaedt, L. A.; Rice, P. A.; Friedman, J. M.; Steitz, T. A.

    1994-01-01

    The reverse transcriptase from human immunodeficiency virus type 1 is a heterodimer consisting of one 66-kDa and one 51-kDa subunit. The p66 subunit contains both a polymerase and an RNase H domain; proteolytic cleavage of p66 removes the RNase H domain to yield the p51 subunit. Although the polymerase domain of p66 folds into an open, extended structure containing a large active-site cleft, that of p51 is closed and compact. The connection subdomain, which lies between the polymerase and RNa...

  20. Highly Rigid Labdane-Type Diterpenoids from a Chinese Liverwort and Light-Driven Structure Diversification.

    Science.gov (United States)

    Zhou, Jinchuan; Zhang, Jiaozhen; Cheng, Aixia; Xiong, Yuanxin; Liu, Lei; Lou, Hongxiang

    2015-07-17

    Two unprecedented labdane-type diterpenoids haplomintrins A (1) and B (2) with six rings system were isolated from a Chinese liverwort Haplomitrium mnioides. Light-driven reaction of homologous haplomitrenonolides C (6), A (4), and D (3) afforded haplomintrins A-C (1, 2, and 7), respectively, while 4 was converted to more complex congeners haplomintrins D-G (8-11) through intramolecular cyclization. Formation of 1 and 2 from compounds 6 and 4, respectively, helps us to postulate that a photochemical reaction is involved in the biosynthetic pathway. These structure features can be used as molecular markers of H. mnioides, and their allelopathic effects are also preliminarily tested. PMID:26111119

  1. Development of radiation hard edgeless detectors with current terminating structure on p-type silicon

    Science.gov (United States)

    Verbitskaya, E.; Eremin, V.; Ruggiero, G.

    2011-12-01

    The development of edgeless Si detectors was stimulated by the tasks of the total pp cross-section study in the TOTEM experiment at the Large Hadron Collider at CERN. For this, the dead region at the detector diced side should be reduced below 50 ?m. This requirement is successfully realized in edgeless Si detectors with current terminating structure (CTS), which are now operating at LHC. The development of the experiment and future LHC upgrade need the elaboration of radiation hard version of edgeless Si detectors. The current investigation represents an extension in understanding on edgeless detectors operation and development of a new issue - edgeless detectors with CTS on p-type Si.

  2. Thermal and thermal stress analysis of a pool type LMFBR deck structure

    International Nuclear Information System (INIS)

    The thermal capabilities of the ANSYS code were used to construct a thermal model of a pool type LMFBR system. This model included the primary tank of hot sodium covered by the concrete deck. Included in the geometry were the pump, heat exchanger, and control rod penetrations, and the metallic insulation underneath the concrete. The model included radiation and conduction of heat from the hot sodium to the concrete deck, and the cooling of the concrete via water pipes embedded in it. Thermal stresses are calculated within the code for the various plate and shell steel elements used in the code to represent different parts of the structure. This study provides a basis for studying the effect of insulation and coolant in the design of the deck structure. (orig.)

  3. Creep deformation and rupture behavior of type 304/308 stainless steel structural weldments

    International Nuclear Information System (INIS)

    The creep deformation and rupture of type 304/308 stainless steel structural weldments at 5930C (11000F) was experimentally investigated to study the comparative behavior of the base metal and weld metal constituents. The tests were conducted in support of ORNL's program to develop high-temperature structural design methods applicable to liquid-metal fast breeder reactor (LMFBR) system components that operate in the creep range. The specimens used were thin-walled, right circular cylinders capped with either flat or hemispherical heads and tested under internal gas pressure. Circumferential welds were located in different regions of the cylinder or head and, with one exception, were geometrically duplicated by all base metal regions in companion specimens. Results are presented on the comparative deformation and rupture behavior of selected points in the base metal and weldment regions of the different specimens and on the overall surface strains for selected specimens

  4. Structural changes in human type I collagen fibrils investigated by force spectroscopy

    International Nuclear Information System (INIS)

    In the field of biomechanics, collagen fibrils are believed to be robust mechanical structures characterized by a low extensibility. Until very recently, information on the mechanical properties of collagen fibrils could only be derived from ensemble measurements performed on complete tissues such as bone, skin, and tendon. Here, we measure force-elongation/relaxation profiles of single collagen fibrils using atomic force microscopy (AFM)-based force spectroscopy (FS). The elongation profiles show that in vitro-assembled human type I collagen fibrils are characterized by a large extensibility. Numerous discontinuities and a plateau in the force profile indicate major reorganization occurring within the fibrils in the 1.5- to 4.5-nN range. Our study demonstrates that newly assembled collagen fibrils are robust structures with a significant reserve of elasticity that could play a determinant role in the extracellular matrix (ECM) remodeling associated with tissue growth and morphogenesis

  5. Heterotic and type II orientifold compactifications on SU(3) structure manifolds

    Energy Technology Data Exchange (ETDEWEB)

    Benmachiche, I.

    2006-07-15

    We study the four-dimensional N=1 effective theories of generic SU(3) structure compactifications in the presence of background fluxes. For heterotic and type IIA/B orientifold theories, the N=1 characteristic data are determined by a Kaluza-Klein reduction of the fermionic actions. The Kaehler potentials, superpotentials and the D-terms are entirely encoded by geometrical data of the internal manifold. The background flux and the intrinsic torsion of the SU(3) structure manifold, gives rise to contributions to the four-dimensional F-terms. The corresponding superpotentials generalize the Gukov-Vafa-Witten superpotential. For the heterotic compactification, the four-dimensional fermionic supersymmetry variations, as well as the conditions on supersymmetric vacua, are determined. The Yukawa couplings of the theory turn out to be similar to their Calabi-Yau counterparts. (Orig.)

  6. Widespread distribution and structural diversity of Type IV IRESs in members of Picornaviridae.

    Science.gov (United States)

    Asnani, Mukta; Kumar, Parimal; Hellen, Christopher U T

    2015-04-01

    Picornavirus genomes contain internal ribosomal entry sites (IRESs) that promote end-independent translation initiation. Five structural classes of picornavirus IRES have been identified, but numerous IRESs remain unclassified. Here, previously unrecognized Type IV IRESs were identified in members of three proposed picornavirus genera (Limnipivirus, Pasivirus, Rafivirus) and four recognized genera (Kobuvirus, Megrivirus, Sapelovirus, Parechovirus). These IRESs are ~230-420 nucleotides long, reflecting heterogeneity outside a common structural core. Closer analysis yielded insights into evolutionary processes that have shaped contemporary IRESs. The presence of related IRESs in diverse genera supports the hypothesis that they are heritable genetic elements that spread by horizontal gene transfer. Recombination likely also accounts for the exchange of some peripheral subdomains, suggesting that IRES evolution involves incremental addition of elements to a pre-existing core. Nucleotide conservation is concentrated in ribosome-binding sites, and at the junction of helical domains, likely to ensure orientation of subdomains in an active conformation. PMID:25726971

  7. Ag-2223 (Bi) tapes structure and superconducting properties in dependence of initial powder type

    International Nuclear Information System (INIS)

    An investigation was carried out into the critical properties and specific features of structure in composite tapes with a core material of composition 2:2:2:3.2 in bismuth system produced by freeze drying technique and taken at different stages of the synthesis process. Consideration is given to powder behavior in the process of cold drawing and rolling of composite tapes followed by heat treatment under similar condition as well as to evolution of microstructure, specificity of texture and kinetics of superconducting phase formation. It is shown that the most favorable type of structure in heat treated superconductors develops when core material powder is used in the form of a precursor consisting of fine mixture of dioxides and ''2212'' phase resultant from calcination within the interval 750--800 C. The critical current density more than 104 A/cm2 at 77 K was achieved in the composite tapes. The results of testing for small coils are presented

  8. Ion beam irradiation effects in strontium zirconium phosphate with NZP-structure type

    International Nuclear Information System (INIS)

    Ceramics with the sodium zirconium phosphate or NZP type structure have potential as nuclear waste form and inert matrix materials. For both applications the material will be subjected to self-radiation damage from ?-decay of the incorporated actinides. In this study, ion-beam irradiation using Au- and He-ions has been used to simulate the consequences of ?-decay and the effects of irradiation on the structural and macroscopic properties (density and hardness) have been investigated. Irradiation by Au-ions resulted in a significant volume contraction of ?7%, a reduction in hardness of ?30% and a loss in long-range order at fluences above 1014 Au-ions/cm2. In contrast, little effect on the material properties was noted for samples irradiated with He-ions up to a fluence of 1017 ions/cm2. Thermal annealing was investigated for the highest fluence Au-ion irradiated sample and significant decomposition was observed

  9. Labyrinth-type domain structure of heteroepitaxial SrMnO2.5 film

    Science.gov (United States)

    Kobayashi, Shunsuke; Ikuhara, Yuichi; Yamamoto, Takahisa

    2013-06-01

    SrMnO2.5 films grown on SrTiO3 and LSAT substrates were prepared and oxygen vacancies in the films were directly confirmed by annular bright-field imaging in a scanning transmission electron microscope. The SrMnO2.5 films show a unique maze like pattern of domains, i.e., a labyrinth-type domain structure, that arises from relaxation of strain induced by lattice mismatches. The behavior of the domain widths is explained by the geometrical relationship for estimating of the average distance of misfit dislocations. We present useful principles for controlling the domain structures with a view to potential practical applications.

  10. Crystal structures of Helicobacter pylori type II dehydroquinase inhibitor complexes: new directions for inhibitor design.

    Science.gov (United States)

    Robinson, David A; Stewart, Kirsty A; Price, Nicholas C; Chalk, Peter A; Coggins, John R; Lapthorn, Adrian J

    2006-02-23

    The crystal structures of the type II dehydroquinase (DHQase) from Helicobacter pylori in complex with three competitive inhibitors have been determined. The inhibitors are the substrate analogue 2,3-anhydroquinate (FA1), citrate, and an oxoxanthene sulfonamide derivative (AH9095). Despite the very different chemical nature of the inhibitors, in each case the primary point of interaction with the enzyme is via the residues that bind the C1 functionalities of the substrate, 3-dehydroquinate, i.e., N76, H102, I103, and H104. The DHQase/AH9095 complex crystal structure shows that sulfonamides can form a scaffold for nonsubstrate-like inhibitors and identifies a large conserved hydrophobic patch at the entrance to the active site as a locus that can be exploited in the development of new ligands. PMID:16480265

  11. Structural variations of staphylococcal cassette chromosome mec type IVa in Staphylococcus aureus clonal complex 8 and unrelated lineages

    DEFF Research Database (Denmark)

    Damborg, Peter Panduro; Bartels, Mette Damkjær

    2011-01-01

    PCR mapping of staphylococcal cassette chromosome mec type IVa and adjacent mobile elements in 94 methicillin-resistant Staphylococcus aureus (MRSA) strains identified two primary structures (A and B) that could be further classified into two (A1 and A2) and five (B1 to B5) variants, primarily based on structural differences in the orfX-J3 region. While spa type t008 (USA300) invariably contained the A variants, other spa types belonging to clonal complex 8 and unrelated lineages generally contained B variants. These findings have important implications for the typing and identification of MRSA strains containing B variants.

  12. Structural and magnetic Properties of TbZn-substituted calcium barium M-type nano-structured hexa-ferrites

    International Nuclear Information System (INIS)

    Highlights: • Tb–Zn substituted Ca0.5Ba0.5Fe12O19 samples exhibit single magnetoplumbite phase. • Lattice parameters a and c have increasing values. • Coercivity can be tuned at lower substitution level • Crystallites size was found in the range 18–25 nm by TEM and by Scherrer formula. • These hexa-ferrites are suitable for microwave devices and magnetic recording media. -- Abstract: Effect of TbZn substitution on the structural and magnetic properties of Ca0.5Ba0.5?xTbxZnyFe12?yO19, (x = 0.00–0.10; y = 0.00–1.00) ferrites prepared by sol–gel auto combustion is reported. The synthesized samples were characterized by Fourier transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy, transmission electron microscopy and Vibrating Sample magnetometery. The X-ray diffraction analysis confirmed single phase M-type hexa-ferrite structure. The lattice parameters were found to increase as TbZn contents increases, which is attributed to the ionic sizes of the implicated cations. The TbZn seems to be completely soluble in the lattice. The results of scanning electron microscopy and transmission electron microscopy shows that the grain size decreases with increase of TbZn substitution. The coercivity values (1277–2025 Oe) of all samples lies in the range of M-type hexa-ferrite and indicate that an increase of anisotropy was achieved by substitution of TbZn, while the size of nanoparticles was drastically reduced between 18 and 25 nm. The increased anisotropy and fine particle size are useful for many applications, such as improving signal noise ratio of recording devices

  13. Structural and magnetic Properties of TbZn-substituted calcium barium M-type nano-structured hexa-ferrites

    Energy Technology Data Exchange (ETDEWEB)

    Khan, Hasan M. [Department of Physics, Bahauddin Zakariya University, Multan 60800 (Pakistan); Department of Electronics, University of York, York YO10 5DD (United Kingdom); Islam, M.U., E-mail: dr.misbahulislam@bzu.edu.pk [Department of Physics, Bahauddin Zakariya University, Multan 60800 (Pakistan); Xu, Yongbing [Department of Electronics, University of York, York YO10 5DD (United Kingdom); Nanjing–York International Centre of Spintronics and Nano-Engineering, Nanjing University, Nanjing 210093 (China); Asif Iqbal, M. [Department of Physics, Bahauddin Zakariya University, Multan 60800 (Pakistan); National University of Science and Technology, College of E and ME, Islamabad (Pakistan); Ali, Irshad [Department of Physics, Bahauddin Zakariya University, Multan 60800 (Pakistan)

    2014-03-15

    Highlights: • Tb–Zn substituted Ca{sub 0.5}Ba{sub 0.5}Fe{sub 12}O{sub 19} samples exhibit single magnetoplumbite phase. • Lattice parameters a and c have increasing values. • Coercivity can be tuned at lower substitution level • Crystallites size was found in the range 18–25 nm by TEM and by Scherrer formula. • These hexa-ferrites are suitable for microwave devices and magnetic recording media. -- Abstract: Effect of TbZn substitution on the structural and magnetic properties of Ca{sub 0.5}Ba{sub 0.5?x}Tb{sub x}Zn{sub y}Fe{sub 12?y}O{sub 19}, (x = 0.00–0.10; y = 0.00–1.00) ferrites prepared by sol–gel auto combustion is reported. The synthesized samples were characterized by Fourier transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy, transmission electron microscopy and Vibrating Sample magnetometery. The X-ray diffraction analysis confirmed single phase M-type hexa-ferrite structure. The lattice parameters were found to increase as TbZn contents increases, which is attributed to the ionic sizes of the implicated cations. The TbZn seems to be completely soluble in the lattice. The results of scanning electron microscopy and transmission electron microscopy shows that the grain size decreases with increase of TbZn substitution. The coercivity values (1277–2025 Oe) of all samples lies in the range of M-type hexa-ferrite and indicate that an increase of anisotropy was achieved by substitution of TbZn, while the size of nanoparticles was drastically reduced between 18 and 25 nm. The increased anisotropy and fine particle size are useful for many applications, such as improving signal noise ratio of recording devices.

  14. Structure and Stellar Content of the Nearest Nuclear Clusters in Late-Type Spiral Galaxies

    Science.gov (United States)

    Barth, Aaron

    2010-09-01

    HST surveys have shown that nuclear star clusters are nearly ubiquitous in late-type, bulgeless disk galaxies. In early-type galaxies, the central black hole mass correlates with the bulge mass and velocity dispersion, but the relationship between black hole mass and host galaxy properties in bulgeless galaxies is not yet understood. Some nuclear clusters {such as the one in M33} do not contain a central massive black hole at all, while other late-type galaxies {such as NGC 4395} are known to contain accretion-powered active nuclei within their nuclear clusters, indicating that a central black hole is present. But, the overall "occupation fraction" of black holes within nuclear clusters is largely unconstrained. Measurement of the structure, dynamics, and stellar content of nuclear star clusters is an important pathway toward understanding the demographics of low-mass black holes in late-type galaxies.We propose to obtain multi-filter WFC3 UV, optical, and near-IR images of 10 of the nearest and brightest nuclear clusters in late-type spiral galaxies. We will use the new WFC3 data to measure the cluster radial profiles, to search for color gradients, and in combination with ground-based spectroscopy and stellar population modeling, to determine the stellar masses of the clusters. Since nuclear clusters are known to contain stellar populations with a wide range of ages, the broad wavelength coverage of our data will provide new leverage to constrain the star formation history of the clusters. We will carry out dynamical modeling for the clusters, using the cluster structural parameters and stellar M/L ratios measured from the WFC3 data and kinematics measured from ground-based, adaptive-optics assisted integral-field spectroscopy {already obtained or approved for 8 of the 10 targets}. This will yield tight new constraints on the masses of intermediate-mass black holes {IMBH} within the clusters, and may result in the first dynamical detections of IMBHs in the nuclei of late-type spirals.

  15. Structural and functional cardiac changes in myotonic dystrophy type 1: a cardiovascular magnetic resonance study

    Directory of Open Access Journals (Sweden)

    Hermans Mieke CE

    2012-07-01

    Full Text Available Abstract Background Myotonic dystrophy type 1 (MD1 is a neuromuscular disorder with potential involvement of the heart and increased risk of sudden death. Considering the importance of cardiomyopathy as a predictor of prognosis, we aimed to systematically evaluate and describe structural and functional cardiac alterations in patients with MD1. Methods Eighty MD1 patients underwent physical examination, electrocardiography (ECG, echocardiography and cardiovascular magnetic resonance (CMR. Blood samples were taken for determination of NT-proBNP plasma levels and CTG repeat length. Results Functional and structural abnormalities were detected in 35 patients (44%. Left ventricular systolic dysfunction was found in 20 cases, left ventricular dilatation in 7 patients, and left ventricular hypertrophy in 6 patients. Myocardial fibrosis was seen in 10 patients (12.5%. In general, patients had low left ventricular mass indexes. Right ventricular involvement was uncommon and only seen together with left ventricular abnormalities. Functional or structural cardiac involvement was associated with age (p = 0.04, male gender (p Conclusions CMR can be useful to detect early structural and functional myocardial abnormalities in patients with MD1. Myocardial involvement is strongly associated with conduction abnormalities, but a normal ECG does not exclude myocardial alterations. These findings lend support to the hypothesis that MD1 patients have a complex cardiac phenotype, including both myocardial and conduction system alteration.

  16. Shear strength in corner region of reinforced concrete duct type structures to be embedded in soil

    International Nuclear Information System (INIS)

    Reinforced concrete ducts for accommodating emergency cooling water pipes are generally embedded in soil. The structures is classified as one of the most important structures in terms of earthquake resistant design. During a strong earthquake it is subjected to shear deformations in concerted movement with surrounding soil. The comer regions of the duct should be designed against shear with moment combined. However, the complicated stress conditions in the region render the design more intricate in comparison with the case of simple determinate RC beam type structures. With the above situation in mind an experimental study was conducted, in which prototype as well as one half scale models representing the stress conditions in the region of interest were loaded and brought to failure in shear. The cross section of the prototype test model without shear reinforcements was 60 (height) x 30cm (width), and the tensile reinforcement ratio was 2.58%. The following results were obtained within the limit of the experimental study. (1) The shear capacity predicted by Japanese Design Code for linear RC members over-estimated the experimental ones with a considerably large safety margin of 4.4-5.0. (2) An improved design procedure to be applied to the specific structure was proposed, which gave a reasonable safety factor against shear failure of 1.7-2.0. (3) Combined smeared and discrete cracking model was utilized to simulate the shear failure mechanism, which could realisticallailure mechanism, which could realistically pursue experimental behaviors. (author)

  17. UCr4C4 with filled MoNi4 type structure

    International Nuclear Information System (INIS)

    The title compound was prepared by arc melting coldpressed pellets of the elemental components with subsequent annealing at both 800 oC or 1100 oC. UCr4C4 crystallizes tetragonal, space group I4/m, a = 0.79363(4)nm, c = 0.30754(3)nm, V = 0.19470nm3 with Z = 2 formula units per cell. The structure was determined from single-crystal X-ray data and refined to a residual of R = 0.027 for 16 variable parameters and 279 strucute factors. The positions of the metal atoms correspond to those of the MoNi4 type structure. The carbon atoms occupy octahedral vois formed by four chromium and two adjacent uranium atoms. Chemical bonding in UCr4C4 and in other interstitial compounds is briefly discussed. The average valence electron number of the metal atoms is usually greater for the unfilled (host) structure than for the corresponding filled structure. (Author)

  18. New mixed-valence chromium structure type: NH4Cr(CrO4)2

    International Nuclear Information System (INIS)

    Synthesis and crystal structure of a new structure type of mixed Cr(III)/Cr(VI) chromates is reported. NH4Cr(CrO4)2 was prepared from CrO3 in the presence of (NH4)2Ce(NO3)6. Since this is the first preparation of mixed valence ternary chromium oxides from aqueous solution, a reaction pathway for this synthesis is suggested. The crystal structure of NH4Cr(CrO4)2 has been determined from three-dimensional X-ray data collected at low temperature, 173K. The structure belongs to the orthorhombic space group Pnma, with a=14.5206(10), b=5.4826(4), c=8.7041(7)A and Z=4. The title compound consists of corner-sharing chromium(III) octahedra and chromium(VI) tetrahedra forming a three-dimensional network with the composition [Cr(CrO4)2]nn-, containing channels in which zigzag rows of ammonium ions balance the net charge

  19. Structural, infrared, magnetic and microwave absorption properties of rare earth doped X-type hexagonal nanoferrites

    Energy Technology Data Exchange (ETDEWEB)

    Sadiq, Imran, E-mail: khanphysics@yahoo.com [Department of Physics, Bahauddin Zakariya University, Multan 60800 (Pakistan); Khan, Imran [Department of Physics, Bahauddin Zakariya University, Multan 60800 (Pakistan); Rebrov, Evgeny V. [School of Chemistry and Chemical Engineering, Queen’s University Belfast (United Kingdom); Ashiq, Muhammad Naeem [Institute of Chemical Sciences, Bahauddin Zakariya University, Multan 60800 (Pakistan); Naseem, Shahzad [Centre for Solid State Physics, University of Punjab, Lahore (Pakistan); Rana, M.U., E-mail: mazharrana@bzu.edu.pk [Department of Physics, Bahauddin Zakariya University, Multan 60800 (Pakistan)

    2013-09-05

    Highlights: •A series of X-type hexagonal ferrites were prepared by sol–gel method. •The XRD analysis showed that the X-type hexagonal structure. •The c/a ratio of these samples falls in the range of X-type hexagonal ferrites. •The magnetic properties enhances with the increase of Nd–Co contents. •The samples show the reflection loss at smaller frequencies. -- Abstract: A series of Sr{sub 2?x}Nd{sub x}Ni{sub 2} Fe{sub 28?y}Co{sub y}O{sub 46} (x = 0.02, 0.04, 0.06, 0.08, 0.10 and y = 0.1, 0.2, 0.3, 0.4, 0.5) X-type hexagonal ferrites has been prepared by sol–gel method at 1250 °C for 6 h. XRD analysis shows the single phase of the prepared ferrites material. The lattice constant values and c/a ratio shows that the present assembled material belongs to the family X-type hexagonal ferrites. The peaks in the FTIR spectra are the characteristics of the hexagonal ferrites. The crystallite size measured by Scherer formula is in good agreement with the crystallite size measured by TEM and HRTEM. The enhancement in the magnetic properties can easily be observed with the doping of rare earth element Nd{sup 3+} and divalent Co{sup 2+}. Due to high saturation and low coercivity values the present material can be good microwave absorber. The temperature dependent saturation and remanance magnetization decreases monotonically with temperature. The minimum value of reflection loss enhances with the substituent and the attenuation constant results are in agreement with reflection loss results.

  20. Structural, infrared, magnetic and microwave absorption properties of rare earth doped X-type hexagonal nanoferrites

    International Nuclear Information System (INIS)

    Highlights: •A series of X-type hexagonal ferrites were prepared by sol–gel method. •The XRD analysis showed that the X-type hexagonal structure. •The c/a ratio of these samples falls in the range of X-type hexagonal ferrites. •The magnetic properties enhances with the increase of Nd–Co contents. •The samples show the reflection loss at smaller frequencies. -- Abstract: A series of Sr2?xNdxNi2 Fe28?yCoyO46 (x = 0.02, 0.04, 0.06, 0.08, 0.10 and y = 0.1, 0.2, 0.3, 0.4, 0.5) X-type hexagonal ferrites has been prepared by sol–gel method at 1250 °C for 6 h. XRD analysis shows the single phase of the prepared ferrites material. The lattice constant values and c/a ratio shows that the present assembled material belongs to the family X-type hexagonal ferrites. The peaks in the FTIR spectra are the characteristics of the hexagonal ferrites. The crystallite size measured by Scherer formula is in good agreement with the crystallite size measured by TEM and HRTEM. The enhancement in the magnetic properties can easily be observed with the doping of rare earth element Nd3+ and divalent Co2+. Due to high saturation and low coercivity values the present material can be good microwave absorber. The temperature dependent saturation and remanance magnetization decreases monotonically with temperature. The minimum value of reflection loss enhances with the substituent and the attenuation constant results are in agreement with reflection loss results

  1. Generalized N=1 and N=2 structures in M-theory and type II orientifolds

    CERN Document Server

    Graña, Mariana

    2012-01-01

    We consider M-theory and type IIA reductions to four dimensions with N=2 and N=1 supersymmetry and discuss their interconnection. Our work is based on the framework of Exceptional Generalized Geometry (EGG), which extends the tangent bundle to include all symmetries in M-theory and type II string theory, covariantizing the local U-duality group E7. We describe general N=1 and N=2 reductions in terms of SU(7) and SU(6) structures on this bundle and thereby derive the effective four-dimensional N=1 and N=2 couplings, in particular we compute the Kahler and hyper-Kahler potentials as well as the triplet of Killing prepotentials (or the superpotential in the N=1 case). These structures and couplings can be described in terms of forms on an eight-dimensional tangent space where SL(8) contained in E7 acts, which might indicate a description in terms of an eight-dimensional internal space, similar to F-theory. We finally discuss an orbifold action in M-theory and its reduction to O6 orientifolds, and show how the pr...

  2. Structure-and-mechanism-based design and discovery of type II Mycobacterium tuberculosis dehydroquinate dehydratase inhibitors.

    Science.gov (United States)

    Yao, Yuan; Li, Ze-Sheng

    2014-01-01

    Mycobacterium tuberculosis is the causative agent of tuberculosis, a lethal infection disease that attacks the lungs. Now it becomes the major global health risk because of very long latent period, the persistent increase of new cases, and the emergence of multidrug-resistant and extensively drug-resistant strains. Therefore, there is an urgent need for the development of new, safe and more efficient tuberculosis drugs. The shikimate pathway has been considered as the attractive drug target due to its essentiality in algae, higher plants, bacteria, and fungi, but absence from mammals. In this review, we focus on the recent development of a wide variety of inhibitors of type II Mycobacterium tuberculosis dehydroquinate dehydratase, the third enzyme of this pathway. The structural and mechanistic features of the enzyme for the design and discovery of the inhibitors have been described. The key factors on the structure, binding, and affinity of the inhibitors have been also highlighted. This may direct the further development of type II Mycobacterium tuberculosis dehydroquinate dehydratase inhibitors as potent tuberculosis drugs. PMID:24236726

  3. Coronal Thermal Structure and Abundance of Super-Metal-Rich Late-Type Stars

    Science.gov (United States)

    Brickhouse, Nancy; Mushotzky, Richard F. (Technical Monitor)

    2002-01-01

    This report covers the NASA grant NAG5-9943 for Cycle 1 XMM Guest Observer Program. The project is entitled 'Coronal Thermal Structure and Abundances of Super-Metal-Rich Late-Type Stars.' This observation is for grating spectroscopy of 30 Ari, a late-type star with very high metallicity (about twice solar). The goal is to use extreme cases to help understand how abundances change from the photosphere to the corona. The target was obtained by XMM-Newton on 2001 January 16 for 28000 sec. Data processing could not proceed until last fall because the SAS RGS software did not work. A poster was presented at the conference 'New Visions of the X-ray Universe in the XMM-Newton and Chandra Era,' held in Noordwijk 26-30 November 2001. The paper was entitled,'Coronal Abundances and Thermal Structure of the Super-Metal-Rich Star 30 Ari,'. The poster presented analysis of EPIC and RGS data to determine the individual abundances from the star and the emission measure distribution as a function of temperature. Results were compared with previous results on this star by our team using ASCA data.

  4. New type structures of a-Si solar cell submodules fabricated by microscopic hole spacing technique

    International Nuclear Information System (INIS)

    A laser patterning method is investigated as a fabrication technique for microscopic holes on a-Si solar cells. The optimum laser patterning conditions calculated from a three-dimensional thermal analysis are confirmed by the experiments. Microscopic holes can be fabricated on an a-Si solar cell using this method without any significant damage to the photovoltaic performances around the holes. The authors have applied this technique to the two unique structures for a-Si solar cell submodules: one is a see-through integrated-type submodule and the other is a through-hole contact (THC) integrated-type submodule. The authors have optimized the hole pattern of see-through submodules for the purpose of obtaining both high transmittance and light uniformity. The performance for THC submodules is estimated by the numerical simulation based on a distributed equivalent circuit model. It is found that a 10% increase in the maximum output power can be expected using this structure

  5. The SLACS Survey. VIII. The Relation between Environment and Internal Structure of Early-Type Galaxies

    Science.gov (United States)

    Treu, Tommaso; Gavazzi, Raphaël; Gorecki, Alexia; Marshall, Philip J.; Koopmans, Léon V. E.; Bolton, Adam S.; Moustakas, Leonidas A.; Burles, Scott

    2009-01-01

    We study the relation between the internal structure of early-type galaxies and their environment using 70 strong gravitational lenses from the SLACS Survey. The Sloan Digital Sky Survey (SDSS) database is used to determine two measures of overdensity of galaxies around each lens—the projected number density of galaxies inside the tenth nearest neighbor (?10) and within a cone of radius one h -1 Mpc (D 1). Our main results are as follows. (1) The average overdensity is somewhat larger than unity, consistent with lenses preferring overdense environments as expected for massive early-type galaxies (12/70 lenses are in known groups/clusters). (2) The distribution of overdensities is indistinguishable from that of "twin" nonlens galaxies selected from SDSS to have the same redshift and stellar velocity dispersion ?*. Thus, within our errors, lens galaxies are an unbiased population, and the SLACS results can be generalized to the overall population of early-type galaxies. (3) Typical contributions from external mass distribution are no more than a few percent in local mass density, reaching 10-20% (~0.05-0.10 external convergence) only in the most extreme overdensities. (4) No significant correlation between overdensity and slope of the mass-density profile of the lens galaxies is found. (5) Satellite galaxies (those with a more luminous companion) have marginally steeper mass-density profiles (as quantified by f SIE = ?*/?SIE = 1.12 ± 0.05 versus 1.01 ± 0.01) and smaller dynamically normalized mass enclosed within the Einstein radius (?log M Ein/M dim differs by -0.09 ± 0.03 dex) than central galaxies (those without). This result suggests that tidal stripping may affect the mass structure of early-type galaxies down to kpc scales probed by strong lensing, when they fall into larger structures. Based on observations made with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555. These observations are associated with programs 10174, 10587, 10886, 10494, and 10798.

  6. Combined Crystal Structure of a Type I Cohesin: MUTATION AND AFFINITY BINDING STUDIES REVEAL STRUCTURAL DETERMINANTS OF COHESIN-DOCKERIN SPECIFICITIES.

    Science.gov (United States)

    Cameron, Kate; Weinstein, Jonathan Y; Zhivin, Olga; Bule, Pedro; Fleishman, Sarel J; Alves, Victor D; Gilbert, Harry J; Ferreira, Luís M A; Fontes, Carlos M G A; Bayer, Edward A; Najmudin, Shabir

    2015-06-26

    Cohesin-dockerin interactions orchestrate the assembly of one of nature's most elaborate multienzyme complexes, the cellulosome. Cellulosomes are produced exclusively by anaerobic microbes and mediate highly efficient hydrolysis of plant structural polysaccharides, such as cellulose and hemicellulose. In the canonical model of cellulosome assembly, type I dockerin modules of the enzymes bind to reiterated type I cohesin modules of a primary scaffoldin. Each type I dockerin contains two highly conserved cohesin-binding sites, which confer quaternary flexibility to the multienzyme complex. The scaffoldin also bears a type II dockerin that anchors the entire complex to the cell surface by binding type II cohesins of anchoring scaffoldins. In Bacteroides cellulosolvens, however, the organization of the cohesin-dockerin types is reversed, whereby type II cohesin-dockerin pairs integrate the enzymes into the primary scaffoldin, and type I modules mediate cellulosome attachment to an anchoring scaffoldin. Here, we report the crystal structure of a type I cohesin from B. cellulosolvens anchoring scaffoldin ScaB to 1.84-Å resolution. The structure resembles other type I cohesins, and the putative dockerin-binding site, centered at ?-strands 3, 5, and 6, is likely to be conserved in other B. cellulosolvens type I cohesins. Combined computational modeling, mutagenesis, and affinity-based binding studies revealed similar hydrogen-bonding networks between putative Ser/Asp recognition residues in the dockerin at positions 11/12 and 45/46, suggesting that a dual-binding mode is not exclusive to the integration of enzymes into primary cellulosomes but can also characterize polycellulosome assembly and cell-surface attachment. This general approach may provide valuable structural information of the cohesin-dockerin interface, in lieu of a definitive crystal structure. PMID:25934389

  7. Types of structural chromosome aberrations and their incidences in human spermatozoa X-irradiated in vitro

    International Nuclear Information System (INIS)

    The authors studied the effects of in vitro X-irradiation on human sperm chromosomes, using our interspecific in vitro fertilization system between human spermatozoa and zona-free hamster oocytes. 28 semen samples from 5 healthy men were exposed to 0.23, 0.45, 0.91 and 1.82 Gy of X-rays. Totals of 2098 and 2862 spermatozoa were karyotyped in the control and the irradiated groups, respectively. The indicence of spermatozoa with X-ray-induced structural chromosome aberrations (Y) increased linearly with increasing dosage (D), being best expressed by the equation, Y = 0.08 + 34.52 D. The incidence of breakage-type aberrations was moe than 9 times higher than that of exchange-type aberrations. Both of them showed linear dose-dependent increases, which were expressed by the regression lines, Y = -0.014 + 0.478 D and Y -0.010 + 0.057 D, respectively. The incidence of chromosome-ltype aberrations was about 6 times higher than that of chromatid-type aberrations. Their dose-dependent increases were expressed by the regression lines, Y = -0.015 + 0.462 D and Y = -0.006 + 0.079 D, respectively. These results are discussed in relation to the previous data obtained with ?-rays. The repair mechanism of X-ray-induced sperm DNA lesions is also discussed. (author). 21 refs.; 4 figs.; 4 tabs

  8. Characteristics of sandwich-type structural elements built of advanced composite materials from three dimensional fabrics

    Directory of Open Access Journals (Sweden)

    Castejón, L.

    1997-12-01

    Full Text Available Sandwich-type structures have proved to be alternatives of great success for several fields of application, and specially in the building sector. This is due to their outstanding properties of .specific rigidity and strength against bending loads and other range of advantages like fatigue and impact resistance, attainment of flat and smooth surfaces, high electric and thermal insulation, design versatility and some others. However, traditional sandwich structures present problems like their tendency towards delamination, stress concentrations in bores or screwed Joints, and pre resistance. These problems are alleviated thanks to the use of new sandwich structures built using three dimensional structures of advanced composite materials, maintaining the present advantages for more traditional sandwich structures. At this rate, these new structures can be applied in several areas where conventional sandwich structures used to be like walls, partitions, floor and ceiling structures, domes, vaults and dwellings, but with greater success.

    Las estructuras tipo sándwich han demostrado ser alternativas de gran éxito para diversos campos de aplicación y, en concreto, en el sector de la construcción, listo es gracias a sus excelentes propiedades de rigidez y resistencia específica frente a cargas de flexión y otra larga lista de ventajas, a la que pertenecen, por ejemplo, su buena resistencia a fatiga, resistencia al impacto, obtención de superficies lisas y suaves, elevado aislamiento térmico y eléctrico, versatilidad de diseño y otras. Sin embargo, las estructuras sándwich, tradicionales presentan una problemática consistente en su tendencia a la delaminación, concentraciones de tensiones ¿aparecidas ante la existencia de agujeros o uniones atornilladas y resistencia al fuego. Estos problemas son pifiados gracias a la aplicación de estructuras novedosas tipo sándwich, construidas a partir de tejidos tridimensionales de materiales compuestos avanzados, manteniéndose las ventajas existentes para las estructuras sándwich tradicionales. De este modo, estas nuevas estructuras pueden ser aplicadas en diversas áreas donde se venían aplicando las estructuras sándwich convencionales, pero con mayor éxito. Como son muros, tabiques, suelos, bóvedas, cúpulas, estructuras de suelo y techo y viviendas.

  9. An Examination of the Influence of Organizational Structure Types and Management Levels on Knowledge Management Practices in Organizations

    Directory of Open Access Journals (Sweden)

    Jen S. Steiger

    2014-05-01

    Full Text Available The purpose of this study was to investigate the difference between organizational structure types, andmanagement levels, in terms of perceived levels of knowledge management practices within organizations. Datawere collected from a sample of 155 individuals employed in San Diego County by way of a web-based survey,and were analyzed using analysis of variance (ANOVA. The results of the study indicate that the knowledgemanagement practices of knowledge transfer, information filtering, and knowledge culture are influenced byorganizational structure type. According to the study, knowledge sharing training is not significantly influencedby organizational structure type. Furthermore, the results of the study indicate there is no significant influence ofmanagement level on the knowledge management practices of knowledge transfer, information filtering,knowledge-sharing training, and knowledge culture. In summary, the results of this study solidify the assertionthat organizational structure types do influence knowledge management practices.

  10. Magnetism, dielectricity and interactive properties of both in the hexagonal ABX3 type compounds with successive structural phase transitions

    International Nuclear Information System (INIS)

    Magnetism, ferroelectricity and concomitant properties of both derived by the partial release of geometrical spin frustration are reviewed for the ABX3 type triangular lattice antiferromagnets with successive structural phase transitions. (author)

  11. Myotonic Dystrophy Type 1 RNA Crystal Structures Reveal Heterogeneous 1 × 1 Nucleotide UU Internal Loop Conformations

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, Amit; Park, HaJeung; Fang, Pengfei; Parkesh, Raman; Guo, Min; Nettles, Kendall W.; Disney, Matthew D. (Scripps)

    2012-03-27

    RNA internal loops often display a variety of conformations in solution. Herein, we visualize conformational heterogeneity in the context of the 5'CUG/3'GUC repeat motif present in the RNA that causes myotonic dystrophy type 1 (DM1). Specifically, two crystal structures of a model DM1 triplet repeating construct, 5'r[{und UU}GGGC(C{und U}G){sub 3}GUCC]{sub 2}, refined to 2.20 and 1.52 {angstrom} resolution are disclosed. Here, differences in the orientation of the 5' dangling UU end between the two structures induce changes in the backbone groove width, which reveals that noncanonical 1 x 1 nucleotide UU internal loops can display an ensemble of pairing conformations. In the 2.20 {angstrom} structure, CUGa, the 5' UU forms a one hydrogen-bonded pair with a 5' UU of a neighboring helix in the unit cell to form a pseudoinfinite helix. The central 1 x 1 nucleotide UU internal loop has no hydrogen bonds, while the terminal 1 x 1 nucleotide UU internal loops each form a one-hydrogen bond pair. In the 1.52 {angstrom} structure, CUGb, the 5' UU dangling end is tucked into the major groove of the duplex. While the canonically paired bases show no change in base pairing, in CUGb the terminal 1 x 1 nucleotide UU internal loops now form two hydrogen-bonded pairs. Thus, the shift in the major groove induced by the 5' UU dangling end alters noncanonical base patterns. Collectively, these structures indicate that 1 x 1 nucleotide UU internal loops in DM1 may sample multiple conformations in vivo. This observation has implications for the recognition of this RNA, and other repeating transcripts, by protein and small molecule ligands.

  12. Community Structure of Skipper Butterflies (Lepidoptera, Hesperiidae) along Elevational Gradients in Brazilian Atlantic Forest Reflects Vegetation Type Rather than Altitude

    OpenAIRE

    Carneiro, Eduardo; Mielke, Olaf Hermann Hendrik; Casagrande, Mirna Martins; Fiedler, Konrad

    2014-01-01

    Species turnover across elevational gradients has matured into an important paradigm of community ecology. Here, we tested whether ecological and phylogenetic structure of skipper butterfly assemblages is more strongly structured according to altitude or vegetation type along three elevation gradients of moderate extent in Serra do Mar, Southern Brazil. Skippers were surveyed along three different mountain transects, and data on altitude and vegetation type of every collection site were recor...

  13. Electronic structure and thermoelectric properties of n - and p -type SnSe from first-principles calculations

    Science.gov (United States)

    Kutorasinski, K.; Wiendlocha, B.; Kaprzyk, S.; Tobola, J.

    2015-05-01

    We present results of the electronic band structure, Fermi surface, and electron transport property calculations in the orthorhombic n - and p -type SnSe, applying the Korringa-Kohn-Rostoker method and the Boltzmann transport approach. The analysis accounted for the temperature effect on crystallographic parameters in P n m a structure as well as the phase transition to C m C m structure at Tc˜807 K. Remarkable modifications of the conduction and valence bands were noticed upon varying crystallographic parameters within the structure before Tc, while the phase transition mostly leads to the jump in the band-gap value. The diagonal components of the kinetic parameter tensors (velocity, effective mass) and resulting transport quantity tensors [electrical conductivity ? , thermopower S , and power factor (PF)] were computed for a wide range of temperature (15-900 K) and hole (p -type) and electron (n -type) concentrations (1017-1021cm-3 ). SnSe is shown to have a strong anisotropy of the electron transport properties for both types of charge conductivity, as expected for the layered structure, with the generally heavier p -type effective masses compared to n -type ones. Interestingly, p -type SnSe has strongly nonparabolic dispersion relations, with the "pudding-mold-like" shape of the highest valence band. The analysis of ? ,S , and PF tensors indicates that the interlayer electron transport is beneficial for thermoelectric performance in n -type SnSe, while this direction is blocked in p -type SnSe, where in-plane transport is preferred. Our results predict that n -type SnSe is potentially even better thermoelectric material than p -type SnSe. Theoretical results are compared with the single-crystal p -SnSe measurements, and good agreement is found below 600 K. The discrepancy between the computational and experimental data, appearing at higher temperatures, can be explained assuming an increase of the hole concentration versus T , which is correlated with the experimental Hall data.

  14. Development of advanced loop-type fast reactor in Japan (3): Easy inspection and high reliable reactor structure in JSFR

    International Nuclear Information System (INIS)

    Japan Atomic Energy Agency Sodium-cooled Fast Reactor (JSFR) has the advanced loop type layout. In this paper, advantages of the advanced loop type reactor are presented in terms of reliability on the reactor structure. As for manufacturability, compact design of the Reactor Vessel (RV) enables its manufacture in a factory. This results in high quality welding and in precise machining of the RV. The RV has high reliability against thermal stress due to application of ring-shaped forgings around high stress parts. Regarding maintainability, the in-vessel structures have simple configurations, so it is comparatively easy for inspection equipments to reach inspection targets. Simultaneous inspection works of loop type reactors are easier than pool type reactors due to separate arrangement of major components. In the JSFR design, sodium boundary area is reduced significantly by innovative technologies, which makes double-walled design of the piping easier, and reduces welding lines. So, the reactor structure of JSFR is desirable to inspect the in-vessel structures efficiently, and there is a prospect of reliable plant operation. Advanced inspection technologies are also under development for the inspection of the in-vessel structures under sodium. In terms of earthquake resistance, a comparable evaluation of earthquake resistance of JSFR and a pool type reactor was carried out. The result showed the loop type reactor is suitable in the region of severe earthquake condition the region of severe earthquake condition rather than the pool type reactor. (authors)

  15. Inelastic response of PCRV structure model with star-type support under horizontal loads

    International Nuclear Information System (INIS)

    The report presents the test results of scaled models for prestressed concrete reactor vessel (PCRV) structure with star-shaped support under horizontal loads. A scale factor of 1/70 to a proto-type PCRV structure for large HTGR is used for both static and dynamic loading test models, while a 1/15 scaled model is used for static loading tests. The static behaviors such as a load-deflection envelope of the 1/70 model are predicted well by an inelastic analysis in consideration with appearance of concrete cracks and reinforcing bar yielding. It is also ascertained by the test results of the 1/15 model under static alternative loads that the same analysis procedure can be applicable to the evaluation of the elastic and inelastic behaviors of PCRV structure with support. Based on the static loading test results of both scaled models, a tri-linearized load-deflection envelope and an equivalent linearized mathematical model for hysteresis loop are assumed in a dynamic analysis. A dynamic response analysis of the 1/70 model subjected to earthquake-like base motion is conducted by the similar manner above-mentioned and the calculated results show a good correlation with the test results

  16. Optimization of chemical structure of Schottky-type selection diode for crossbar resistive memory.

    Science.gov (United States)

    Kim, Gun Hwan; Lee, Jong Ho; Jeon, Woojin; Song, Seul Ji; Seok, Jun Yeong; Yoon, Jung Ho; Yoon, Kyung Jean; Park, Tae Joo; Hwang, Cheol Seong

    2012-10-24

    The electrical performances of Pt/TiO(2)/Ti/Pt stacked Schottky-type diode (SD) was systematically examined, and this performance is dependent on the chemical structures of the each layer and their interfaces. The Ti layers containing a tolerable amount of oxygen showed metallic electrical conduction characteristics, which was confirmed by sheet resistance measurement with elevating the temperature, transmission line measurement (TLM), and Auger electron spectroscopy (AES) analysis. However, the chemical structure of SD stack and resulting electrical properties were crucially affected by the dissolved oxygen concentration in the Ti layers. The lower oxidation potential of the Ti layer with initially higher oxygen concentration suppressed the oxygen deficiency of the overlying TiO(2) layer induced by consumption of the oxygen from TiO(2) layer. This structure results in the lower reverse current of SDs without significant degradation of forward-state current. Conductive atomic force microscopy (CAFM) analysis showed the current conduction through the local conduction paths in the presented SDs, which guarantees a sufficient forward-current density as a selection device for highly integrated crossbar array resistive memory. PMID:22999222

  17. The structural and molecular biology of type I galactosemia: Enzymology of galactose 1-phosphate uridylyltransferase.

    Science.gov (United States)

    McCorvie, Thomas J; Timson, David J

    2011-09-01

    Reduced galactose 1-phosphate uridylyltransferase (GALT) activity is associated with the genetic disease type I galactosemia. This results in an increase in the cellular concentration of galactose 1-phosphate. The accumulation of this toxic metabolite, combined with aberrant glycoprotein and glycolipid biosynthesis, is likely to be the major factor in molecular pathology. The mechanism of GALT was established through classical enzymological methods to be a substituted enzyme in which the reaction with UDP-glucose results in the formation of a covalent, UMP-histidine adduct in the active site. The uridylated enzyme can then react with galactose 1-phosphate to form UDP-galactose. The structure of the enzyme from Escherichia coli reveals a homodimer containing one zinc (II) and one iron (II) ion per subunit. This enzymological and structural knowledge provides the basis for understanding the biochemistry of this critical step in the Leloir pathway. However, a high-resolution crystal structure of human GALT is required to assist greater understanding of the effects of disease-associated mutations. PMID:21793161

  18. Crystal structure of a copper-transporting PIB-type ATPase

    DEFF Research Database (Denmark)

    Gourdon, Pontus; Liu, Xiang-Yu

    2011-01-01

    Heavy-metal homeostasis and detoxification is crucial for cell viability. P-type ATPases of the class IB (PIB) are essential in these processes, actively extruding heavy metals from the cytoplasm of cells. Here we present the structure of a PIB-ATPase, a Legionella pneumophila CopA Cu(+)-ATPase, in a copper-free form, as determined by X-ray crystallography at 3.2 Å resolution. The structure indicates a three-stage copper transport pathway involving several conserved residues. A PIB-specific transmembrane helix kinks at a double-glycine motif displaying an amphipathic helix that lines a putative copper entry point at the intracellular interface. Comparisons to Ca(2+)-ATPase suggest an ATPase-coupled copper release mechanism from the binding sites in the membrane via an extracellular exit site. The structure also provides a framework to analyse missense mutations in the human ATP7A and ATP7B proteins associated with Menkes' and Wilson's diseases.

  19. Novel barium triel/tetrelides with the Pu3Pd5 structure type

    International Nuclear Information System (INIS)

    A series of ternary barium triel(MIII)/tetrel(MIV)-ides Ba3MxIIIM5-xIV(MIII=Ga,In;MIV=Si,Ge,Sn;x=0-0.7) has been prepared from melts of the elements. They all crystallize with the Pu3Pd5 type structure (orthorhombic, space group Cmcm) exhibiting isolated M5 clusters of slightly distorted nido shape (square pyramids). For the silicides, where the binary border compound Ba3Si5 does not exist, the Pu3Pd5 type is stabilized by substituting 0.7 Si atoms per formula unit against Ga (Ba3Ga0.7Si4.3:a=1024.82(1),b=856.58(1),c=1024.18(1) pm, R1=0.0220) or by a very small substitution of In (Ba3In0.1Si4.9:a=1017.8(2),b=852.5(2),c=1020.1(3) pm, R1=0.0406). A comparable situation is found for the corresponding germanides, where 0.7 atoms of In (Ba3In0.7Ge4.3:a=1051.3(2),b=864.05(14),c=1054.7(3) pm, R1=0.0248) or Ga (Ba3GaxGe5-x:a=1035.1(1),b=861.5(1),c=1036.8(1) pm, R1=0.0148) are necessary to stabilize a Ge-rich compound of this structure type. For the stannides, the situation is somewhat different, because the binary phase Ba3Sn5 itself forms the Pu3Pd5 type. In this case, the structure type remains stable up to a Ga content of 0.5 Gremains stable up to a Ga content of 0.5 Ga/f.u. (Ba3Ga0.5Sn4.5:a=1100.41(14),b=896.19(11),c=1111.82(14) pm, R1=0.0169) and also with a substantial In content (Ba3InxSn5-x:x?0.9(1);a=1110.5(2),b=900.0(2),c=1120.7(2) pm, R1=0.0262). As the five-atom nido cluster requires only 24 valence electrons per formula unit according to Zintl and Wade, an excess of electrons would be assumed for the binary tetrelides such as Ba3Sn5 (26 v.e./f.u.) that even the maximal amount of triel substitution 0.7 MIII/f.u. attained in the title compounds cannot sufficiently compensate for. An assessment of the geometric influence of varied valence electron counts however, coupled with a detailed analysis of the calculated electron densities and the partial densities of states in the energy region above the pseudo band gap at 24 v.e./f.u. clearly shows that these excess electrons populate ?-bonding M-p /Ba-d states and actually contribute to a stabilization of the structure. In the range above 25.3 v.e./f.u. predominantly antibonding M-p states are populated, resulting in a widening of the base of the cluster.

  20. Structure of an Essential Type IV Pilus Biogenesis Protein Provides Insights into Pilus and Type II Secretion Systems

    OpenAIRE

    Yamagata, Atsushi; Milgotina, Ekaterina; Scanlon, Karen; Craig, Lisa; Tainer, John A.; Donnenberg, Michael S.

    2012-01-01

    Type IV pili (T4Ps) are long cell surface filaments, essential for microcolony formation, tissue adherence, motility, transformation, and virulence by human pathogens. The enteropathogenic E. colibundle-forming pilus (BFP) is a prototypic T4P assembled and powered by BfpD, a conserved GspE secretion superfamily ATPase held by inner membrane proteins BfpC andBfpE, a GspF-family membrane protein. Although the T4P assembly machinery shares similarity with type II secretion (T2S) systems, the str...

  1. Structure and Functional Analysis of RifR, the Type II Thioesterase from the Rifamycin Biosynthetic Pathway*S?

    OpenAIRE

    Claxton, Heather B.; Akey, David L.; Silver, Monica K; Admiraal, Suzanne J.; Smith, Janet L.

    2009-01-01

    Two thioesterases are commonly found in natural product biosynthetic clusters, a type I thioesterase that is responsible for removing the final product from the biosynthetic complex and a type II thioesterase that is believed to perform housekeeping functions such as removing aberrant units from carrier domains. We present the crystal structure and the kinetic analysis of RifR, a type II thioesterase from the hybrid nonribosomal peptide synthetases/polyketide synthase ...

  2. Structures and free energy landscapes of the A53T mutant-type ?-synuclein protein and impact of A53T mutation on the structures of the wild-type ?-synuclein protein with dynamics.

    Science.gov (United States)

    Coskuner, Orkid; Wise-Scira, Olivia

    2013-07-17

    The A53T genetic missense mutation of the wild-type ?-synuclein (?S) protein was initially identified in Greek and Italian families with familial Parkinson's disease. Detailed understanding of the structures and the changes induced in the wild-type ?S structure by the A53T mutation, as well as establishing the direct relationships between the rapid conformational changes and free energy landscapes of these intrinsically disordered fibrillogenic proteins, helps to enhance our fundamental knowledge and to gain insights into the pathogenic mechanism of Parkinson's disease. We employed extensive parallel tempering molecular dynamics simulations along with thermodynamic calculations to determine the secondary and tertiary structural properties as well as the conformational free energy surfaces of the wild-type and A53T mutant-type ?S proteins in an aqueous solution medium using both implicit and explicit water models. The confined aqueous volume effect in the simulations of disordered proteins using an explicit model for water is addressed for a model disordered protein. We also assessed the stabilities of the residual secondary structure component interconversions in ?S based on free energy calculations at the atomic level with dynamics using our recently developed theoretical strategy. To the best of our knowledge, this study presents the first detailed comparison of the structural properties linked directly to the conformational free energy landscapes of the monomeric wild-type and A53T mutant-type ?-synuclein proteins in an aqueous solution environment. Results demonstrate that the ?-sheet structure is significantly more altered than the helical structure upon A53T mutation of the monomeric wild-type ?S protein in aqueous solution. The ?-sheet content close to the mutation site in the N-terminal region is more abundant while the non-amyloid-? component (NAC) and C-terminal regions show a decrease in ?-sheet abundance upon A53T mutation. Obtained results utilizing our new theoretical strategy show that the residual secondary structure conversion stabilities resulting in ?-helix formation are not significantly affected by the mutation. Interestingly, the residual secondary structure conversion stabilities show that secondary structure conversions resulting in ?-sheet formation are influenced by the A53T mutation and the most stable residual transition yielding ?-sheet occurs directly from the coil structure. Long-range interactions detected between the NAC region and the N- or C-terminal regions of the wild-type ?S disappear upon A53T mutation. The A53T mutant-type ?S structures are thermodynamically more stable than those of the wild-type ?S protein structures in aqueous solution. Overall, the higher propensity of the A53T mutant-type ?S protein to aggregate in comparison to the wild-type ?S protein is related to the increased ?-sheet formation and lack of strong intramolecular long-range interactions in the N-terminal region in comparison to its wild-type form. The specific residual secondary structure component stabilities reported herein provide information helpful for designing and synthesizing small organic molecules that can block the ?-sheet forming residues, which are reactive toward aggregation. PMID:23607785

  3. Evidence for alternative quaternary structure in a bacterial Type III secretion system chaperone

    Directory of Open Access Journals (Sweden)

    Picking Wendy L

    2010-07-01

    Full Text Available Abstract Background Type III secretion systems are a common virulence mechanism in many Gram-negative bacterial pathogens. These systems use a nanomachine resembling a molecular needle and syringe to provide an energized conduit for the translocation of effector proteins from the bacterial cytoplasm to the host cell cytoplasm for the benefit of the pathogen. Prior to translocation specialized chaperones maintain proper effector protein conformation. The class II chaperone, Invasion plasmid gene (Ipg C, stabilizes two pore forming translocator proteins. IpgC exists as a functional dimer to facilitate the mutually exclusive binding of both translocators. Results In this study, we present the 3.3 Å crystal structure of an amino-terminally truncated form (residues 10-155, denoted IpgC10-155 of the class II chaperone IpgC from Shigella flexneri. Our structure demonstrates an alternative quaternary arrangement to that previously described for a carboxy-terminally truncated variant of IpgC (IpgC1-151. Specifically, we observe a rotationally-symmetric "head-to- head" dimerization interface that is far more similar to that previously described for SycD from Yersinia enterocolitica than to IpgC1-151. The IpgC structure presented here displays major differences in the amino terminal region, where extended coil-like structures are seen, as opposed to the short, ordered alpha helices and asymmetric dimerization interface seen within IpgC1-151. Despite these differences, however, both modes of dimerization support chaperone activity, as judged by a copurification assay with a recombinant form of the translocator protein, IpaB. Conclusions From primary to quaternary structure, these results presented here suggest that a symmetric dimerization interface is conserved across bacterial class II chaperones. In light of previous data which have described the structure and function of asymmetric dimerization, our results raise the possibility that class II chaperones may transition between asymmetric and symmetric dimers in response to changes in either biochemical modifications (e.g. proteolytic cleavage or other biological cues. Such transitions may contribute to the broad range of protein-protein interactions and functions attributed to class II chaperones.

  4. Quantification of age-related changes in the structure model type and trabecular thickness of human tibial cancellous

    DEFF Research Database (Denmark)

    Ding, Ming; Hvid, I

    2000-01-01

    Structure model type and trabecular thickness are important characteristics in describing cancellous bone architecture. It has been qualitatively observed that a radical change of trabeculae from plate-like to rod-like occurs in aging, bone remodeling, and osteoporosis. Thickness of trabeculae has traditionally been measured using model-based histomorphometric methods on two-dimensional (2-D) sections. However, no quantitative study has been published based on three-dimensional (3-D) methods on the age-related changes in structure model type and trabecular thickness for human peripheral (tibial) cancellous bone. In this study, 160 human proximal tibial cancellous bone specimens from 40 normal donors, aged 16 to 85 years, were collected. These specimens were micro-computed tomography (micro-CT) scanned, then the micro-CT images were segmented using optimal thresholds. From accurate 3-D data sets, structure model type and trabecular thickness were quantified by means of novel 3-D methods. Structure model type was assessed by calculating the structure model index (SMI). The SMI was quantified based on a differential analysis of the triangulated bone surface of a structure. This technique allows quantification of structure model type, such as plate, rod objects, or mixture of plates or rods. Trabecular thickness is calculated directly from 3-D images, which is especially important for an a priori unknown or changing structure. Furthermore, 2-D trabecular thickness was also calculated based on the plate model. Our results showed that structure model type changed towards more rod-like in the elderly, and that trabecular thickness declined significantly with age. These changes become significant after 80 years of age for human tibial cancellous bone, whereas both properties seem to remain relatively unchanged between 20 and 80 years. Although a fairly close relationship was seen between 3-D trabecular thickness and 2-D trabecular thickness, real 3-D trabecular thickness was significantly underestimated using 2-D method.

  5. OMP-type Algorithm with Structured Sparsity Patterns for Multipath Radar Signals

    CERN Document Server

    Rebafka, Tabea; Charbit, Maurice

    2011-01-01

    A transmitted, unknown radar signal is observed at the receiver through more than one path in additive noise. The aim is to recover the waveform of the intercepted signal and to simultaneously estimate the direction of arrival (DOA). We propose an approach exploiting the parsimonious time-frequency representation of the signal by applying a new OMP-type algorithm for structured sparsity patterns. An important issue is the scalability of the proposed algorithm since high-dimensional models shall be used for radar signals. Monte-Carlo simulations for modulated signals illustrate the good performance of the method even for low signal-to-noise ratios and a gain of 20 dB for the DOA estimation compared to some elementary method.

  6. Crystal structures and some physical properties of perovskite type vanadites of lanthanide-series elements

    International Nuclear Information System (INIS)

    Crystal structures and some physical properties of the perovskite type vanadites of the lanthanide-series elements were studied. LaVO3 and CeVO3 had a tetragonal unit cell and other compounds studied were isostructural with orthorhombic GdFeO3. The conductivity of all compounds showed semiconductive behavior with an activation energy about 0.1 eV. Electrical conductivity at room temperature decreased along the series from LaVO3 to GdVO3, and quasiconstant values were observed from TbVO3 to LuVO3. All the compounds studied, with the exception of LaVO3, SmVO3 and GdVO3, were antiferromagnets with a weak ferromagnetism because of antisymmetric exchange interaction at low temperatures. At high temperature, all the compounds showed paragnetism. (author)

  7. Genetic-Structural relations in some types of spanish uranium deposits

    International Nuclear Information System (INIS)

    On the spanish hercynian areas there are different types of uraniferous deposits, which may be classified in the following groups: Group I, high temperature magmatic deposits, Group II, low temperature veins and Group III supergenic deposits, generated by weathering of the former ones or by lixiviation of the intra granitic uranium. The deposits belonging to Group I are founding the hercynian ge anticlinal; those of Groups II and III, chiefly in the eugeosyncline. The explanation suggested for these genetic-structural relationships assumes that, in the ge anticlinal, uranium would migrate from the dioritic magmas to form and high temperature deposits. In the eugeosyncline, a large fraction of the uranium would migrate towards more differentiated granites, in which it might partially remain or from which it might have been finally concentrated in the epithermal veins or by later tectonic actions. The Group III deposits ar more frequent in the eugeosyncline, due to the greater abundance of more differentiated intrusive rocks. (Author) 16 refs

  8. Measuring Mangrove Type, Structure And Carbon Storage With UAVSAR And ALOS/PALSAR Data

    Science.gov (United States)

    Fatoyinbo, T. E.; Cornforth, W.; Pinto, N.; Simard, M.; Pettorelli, N.

    2011-12-01

    Mangrove forests provide a great number of ecosystem services ranging from shoreline protection (e.g. against erosion, tsunamis and storms), nutrient cycling, fisheries production, building materials and habitat. Mangrove forests have been shown to store very large amounts of Carbon, both above and belowground, with storage capacities even greater than tropical rainforests. But as a result of their location and economic value, they are among the most rapidly changing landscapes in the World. Mangrove extent is limited 1) in total extent to tidally influenced coastal areas and 2) to tropical and subtropical regions. This can lead to difficulties mapping mangrove type (such as degraded vs non degraded, scrub vs tall, dense vs sparse) because of cloud cover and limited access to high-resolution optical data. To accurately quantify the effect of land use and climate change on tropical wetland ecosystems, we must develop effective mapping methodologies that take into account not only extent, but also the structure and health of the ecosystem. This must be done by including Synthetic Aperture Radar (SAR) data. In this research, we used L-band Synthetic Aperture Radar data from the ALOS/PALSAR and UAVSAR instruments over selected sites in the Americas (Sierpe, Costa Rica and Everglades, Florida)and Asia (Sundarbans). In particular, we used the SAR data in combination with other remotely sensed data and field data to 1) map mangrove extent 2) determine mangrove type, health and adjascent land use, and 3) estimate aboveground biomass and carbon storage for entire mangrove systems. We used different classification methodologies such as polarimetric decomposition, unsupervised classification and image segmentation to map mangrove type. Because of the high resolution of the radar data, and its ability to interact with forest volume, we are able to identify mangrove zones and differentiate between mangroves and other forests/land uses. We also integrated InSAR data (SRTM), spaceborne Lidar (GLAS) and field data, in combination with the SAR data to derive aboveground biomass and carbon storage in mangroves. We successfully produced maps of mangrove extent, type, health and carbon storage by using L-band SAR data. Our results show that both UAVSAR and ALOS/PALSAR data alone are effective datasets for mapping mangrove extent, type and other land use. By combining multiple datasets, we were able to determine mangrove biomass without an upper estimation limit and with low error.

  9. Synthesis, structure and electrical properties of rare-earth doped apatite-type lanthanum silicates

    International Nuclear Information System (INIS)

    Highlights: ? La9ASi6O27 ceramics were prepared by pressureless-sintering at 1923 K. ? La9ASi6O27 ceramics have apatite structure. ? The electrical conductivity of La9ASi6O27 increases with temperature. ? The highest conductivity is 1.03 × 10?2 S cm?1 at 1073 K for La9YbSi6O27. - Abstract: Rare-earth doped apatite-type lanthanum silicates, La9ASi6O27 (A = Nd, Sm, Gd, Yb), are synthesized by the high-temperature solid state reaction process. The microstructure and electrical properties of La9ASi6O27 ceramics are investigated by X-ray diffraction, scanning electron microscopy and complex impedance analysis. La9ASi6O27 ceramics are composed of hexagonal apatite-type structure and a very small amount of second phase La2SiO5. The total electrical conductivity of rare-earth doped lanthanum silicates obeys the Arrhenius relation, and gradually increases with increasing temperature from 673 K to 1173 K. Lanthanum silicates doped with Nd or Yb cations exhibit a higher total electrical conductivity than undoped lanthanum silicate. The highest total electrical conductivity value obtained at 773 K is 4.31 × 10?4 S cm?1 for La9NdSi6O27. AtO27. At 1073 K, La9NdSi6O27 and La9YbSi6O27 have a total electrical conductivity of 8.20 × 10?3 S cm?1 and 1.03 × 10?2 S cm?1, respectively, which are distinctly higher than undoped La10Si6O27 (5.84 × 10?3 S cm?1). However, the situation is reversed when Sm or Gd rare-earth cations are doped into lanthanum silicate.

  10. Electronic structure and thermoelectric properties of n- and p-type SnSe from first principles calculations

    OpenAIRE

    Kutorasinski, K.; Wiendlocha, B.; Kaprzyk, S.; Tobola, J.

    2015-01-01

    We present results of electronic band structure, Fermi surface and electron transport properties calculations in orthorhombic $n$- and $p$-type SnSe, applying Korringa-Kohn-Rostoker method and Boltzmann transport approach. The analysis accounted for temperature effect on crystallographic parameters in $Pnma$ structure as well as the phase transition to $CmCm$ structure at $T_c\\sim 807 $K. Remarkable modifications of conduction and valence bands were notified upon varying cry...

  11. Non-degenerate homogeneous $\\epsilon$-K\\"ahler and $\\epsilon$-quaternion K\\"ahler structures of linear type

    OpenAIRE

    Luján, Ignacio; Swann, Andrew

    2013-01-01

    We study the class of non-degenerate homogeneous structures of linear type in the pseudo-K\\"ahler, para-K\\"ahler, pseudo-quaternion K\\"ahler and para-quaternion K\\"ahler cases. We show that these structures characterize spaces of constant holomorphic, para-holomorphic, quaternion and para-quaternion sectional curvature respectively. In addition the corresponding homogeneous models are computed, exhibiting the relation between these kind of structures and the incompleteness o...

  12. Type II Perfect Absorption and Amplification Modes with Controllable Bandwidth in PT-Symmetric/Traditional Bragg Grating Combined Structures

    CERN Document Server

    Huang, C Y; Han, J L; Zheng, J; Xu, J Q

    2013-01-01

    We reveal previously unnoticed Type II perfect absorption and amplification modes of optical scattering system. These modes, in contrast to the counterparts in recent works [Phys. Rev. A 82, 031801 (2010); Phys. Rev. Lett. 106, 093902 (2011).] which could be referred as Type I modes, appear at a continuous region along the real frequency axis with any frequency. The Type II modes can be demonstrated in the PT-symmetric/traditional Bragg grating combined structures. A series of exotic nonreciprocal absorption and amplification behaviours are observed in the combined structures, making them have potential for versatile devices acting simultaneously as a perfect absorber, an amplifier, and an ultra-narrowband filter. Based on the properties of Type II modes, we also propose structures with controllable perfect absorption and amplification bandwidth at any single or multiple wavelengths.

  13. Structural myocardial involvement in adult patients with type 1 myotonic dystrophy

    Directory of Open Access Journals (Sweden)

    Kul Aggarwal

    2013-02-01

    Full Text Available Myotonic dystrophy type 1 (DM1 is the commonest muscular dystrophy in adults, affecting multiple organs in addition to skeletal muscles. Cardiac conduction system abnormalities are well recognized as an important component of DM1 phenotype; however, primary structural myocardial abnormalities, which may predispose these patients to congestive heart failure, are not as well characterized. We reviewed the retrospective analysis of the clinical and echocardiographic findings in adult patients with DM1. Among 27 patients (16 male; age 19-61 years with DM1, the echocardiogram (ECHO was abnormal in 10 (37% including one of 6 patients (16% with congenital myotonic dystrophy. Reduced left ventricular ejection fraction (LVEF ?50% was noted in 5, diastolic dysfunction in 4, left atrial dilatation in 3, left ventricular hypertrophy in 2, apical hypokinesia in 1 and mitral valve prolapse in 3 patients. One patient had paradoxical septal movement in the setting of left bundle branch block. Echocardiographic abnormalities significantly correlated with older age; however, patients with systolic dysfunction on echocardiogram ranged in age from 27 to 52 years including 2 patients aged 27 and 34 years. We can conclude that echocardiographic abnormalities are frequent in adult patients with DM1. The incidence is similar in the classical and congenital type of DM1. Overall, echocardiographic abnormalities in DM1 correlate with increasing age; however, reduced LVEF is observed even at young age. Cardiac assessment and monitoring in adult patients with DM1 should include evaluation for primary myocardial involvement.

  14. Structural characterization and immunostimulating activity of a levan-type fructan from Curcuma kwangsiensis.

    Science.gov (United States)

    Dong, Cai-Xia; Zhang, Li-Jiao; Xu, Rong; Zhang, Gong; Zhou, Ying-Biao; Han, Xiao-Qiang; Zhang, Ying; Sun, Yuan-Xia

    2015-06-01

    A fructan designated as CKNP with apparent molecular weight of 5.3kD was isolated from the hot water extract of Curcuma kwangsiensis through a combination of ion-exchange chromatography on DEAE 650M and gel filtration on Superdex G-200. CKNP was characterized by chemical derivatization as well as HPLC, GC, and GC-MS technologies. Structural studies revealed that CKNP is composed predominately of fructose (96.8%) and a small amount of glucose (3.2%) with a degree of polymerization (DP) of 30-31. It was deduced to be a levan-type fructan containing a backbone composed of (2?6)-linked ?-d-Fruf residues and single ?-d-Fruf residues as side chains branched at the O-1 position along the backbone. Preliminary in vitro bioactive tests on RAW 264.7 murine macrophage cells revealed that the levan-type fructan from C. kwangsiensis shows significant immunostimulating activity based on its ability to stimulate macrophage proliferation and enhance phagocytosis. PMID:25783019

  15. Ce3+ incorporated structural and magnetic properties of M type barium hexaferrites

    Science.gov (United States)

    Pawar, R. A.; Desai, S. S.; Tamboli, Q. Y.; Shirsath, Sagar E.; Patange, S. M.

    2015-03-01

    M type barium hexaferrites BaCexFe12-xO19 (0?x?0.3) (BCFO) were synthesized by the sol-gel auto combination method. Optimum annealing temperature of hexagonal phase was determined by using the TGA analysis. The annealing temperature form the TGA is 1000 °C samples annealed 1000 °C for 5 h to produce M type hexaferrites. X-ray diffraction data run to full Prof Program (Winploter 2010) pattern indicate that samples are single phase hexagonal structure with space group P63/mmc. Lattice parameter 'a' and 'c' increase with increase in Ce content x. Results of field emission scanning electron microscope show that the grains are regular hexagonal platelets with sizes from 0.3 to 1.4 ?m. It is observed that from M-H curve value of the saturation magnetization and coercivity decreases with increasing x. Curie temperature from magnetization with temperature plot is found to decrease with Ce3+ substitution x due to decreases in magnetic interaction.

  16. Electronic Properties of p-Type ?-Doped GaAs Structure under Electric Field

    International Nuclear Information System (INIS)

    We theoretically investigate the electronic properties of p-type ?-doped GaAs inserted into a quantum well under the electric field, at T = 0K.We will investigate the influence of the electric field on the ?-doping concentration for a uniform distribution. The depth of confining potential, the density profile, the Fermi level, the subband energies and the subband populations calculate by solving the Schrodinger and Poisson equations self consistently. It is found that the changes of the electronic properties are quite sensitive to the applied electric field and the doping concentration. As different from single n-type ?-doped structure, we see a replace between the ground light-hole (lh1) subband and the first excited heavy-hole (hh2) subband whenever the external electric field reaches a critical value. We find the abrupt changing of the subband energies and the subband populations whenever the applied electric field reaches a certain value. Also, it is found that the heavy-hole subbands contain many more energy states than the light-hole ones, the population of the heavy-hole levels represent approximately 91% of all the carriers

  17. Numerical model for the analysis of unbounded prestressed structures using the hybrid type finite element method

    International Nuclear Information System (INIS)

    Unbounded prestressed concrete has a growing importance all over the world and may be an useful technique for the structures involved in the construction of nuclear facilities. The absence of bonding means no strain compatibility so that equations developed for reinforced concrete are no longer valid. Practical estimates about the ultimate stress in the unbounded tendons may be obtained with empirical or numerical methods only. In order to contribute to the understanding on the behaviour of unbounded prestressed concrete members, a numerical model has been developed using a hybrid type finite element formulation for planar frame structures. Instead of short elements, as in the conventional finite element formulation, long elements may be used, improving computational efficiency. A further advantage is that the curvature variation within the element is obtained with higher accuracy if compared to the traditional formulation. This feature is important for unbounded tendons since its stresses depend on the whole member deformation. Second order effects in the planar frame are considered with either Updated or Partially Updated Lagrangian approaches. Instantaneous and time dependent behaviour as well as cyclic loads are considered too. Comparison with experimental results for prestressed concrete beams shows the adequacy of the proposed model. (authors)

  18. The Russian oil industry re-structuration: towards the emergence of western type enterprises?

    Energy Technology Data Exchange (ETDEWEB)

    Locatelli, C

    1999-01-01

    The Russian oil industry has undergone fundamental changes since the collapse of the Soviet Empire and its bureaucratic administrative structure, dominated by its various Branch Ministries. The monopoly in the Soviet oil industry has now been replaced by a number of ''oil companies'', some of which are very powerful, the best known of them being Lukoil. These ''joint stock companies'' are the product of a reform aimed essentially at implanting, out of all the numerous organisational arrangements developed in the West, the model of the vertically integrated private firm. Beyond the legal reforms in the Russian oil industry sector, however, the nature of the organisational model that has actually emerged in Russia begs several questions. Many entities, which are complex and highly diversified, are involved in this industry. There are, of course, the many private structures in which the banks sometimes carry a considerable amount of weight. There are also some vertically integrated organisations, but the degree of integration is variable and their method of centralization is based on a specific form of economic logic. It should not be considered, however, that these actors are similar to capitalist-type private enterprises, whose behaviour is regulated by the demands of international competition. Reform of property rights has not been sufficient to create true private enterprise in Russia. (author)

  19. Magnetic spin structure of pyroxene-type MnGeO3

    International Nuclear Information System (INIS)

    Polycrystalline MnGeO3 material was synthesized at 1473 K and ambient pressures using ceramic sintering techniques. Under these conditions the pyroxene-type compound crystallizes in the orthorhombic modification with space group Pbca, as determined from the refinement of the neutron diffraction data. The monoclinic modification, space group C 2/c, was also present at a level of 8.8(4) wt% and the magnetic structures for the two polymorphs at low temperatures have been found simultaneously. The monoclinic form orders magnetically below 34 K; the spin structure can be described using k = (0, 0, 0) in the magnetic space group C 2'/c, having an antiferromagnetic spin arrangement within and between the chains of M1 and M2 sites. The orthorhombic phase of MnGeO3 transforms to a magnetically ordered state with k = (0, 0, 0) and magnetic space group Pb'c'a below 12 K. Spins on M1 sites are aligned along the crystallographic a-axis with a slight non-collinear antiferromagnetic spin arrangement with and between the M1 chains. Spins on M2 sites are also antiferromagnetically coupled; however, one of the three different M1-M2 superexchange pathways within the band of M1 and M2 sites displays a ferromagnetic interaction, while the other two allow antiferromagnetic interaction.

  20. Magnetic spin structure of pyroxene-type MnGeO(3).

    Science.gov (United States)

    Redhammer, G J; Senyshyn, A; Tippelt, G; Roth, G

    2011-06-29

    Polycrystalline MnGeO(3) material was synthesized at 1473 K and ambient pressures using ceramic sintering techniques. Under these conditions the pyroxene-type compound crystallizes in the orthorhombic modification with space group Pbca, as determined from the refinement of the neutron diffraction data. The monoclinic modification, space group C 2/c, was also present at a level of 8.8(4) wt% and the magnetic structures for the two polymorphs at low temperatures have been found simultaneously. The monoclinic form orders magnetically below 34 K; the spin structure can be described using k = (0, 0, 0) in the magnetic space group C 2'/c, having an antiferromagnetic spin arrangement within and between the chains of M1 and M2 sites. The orthorhombic phase of MnGeO(3) transforms to a magnetically ordered state with k = (0, 0, 0) and magnetic space group Pb'c'a below 12 K. Spins on M1 sites are aligned along the crystallographic a-axis with a slight non-collinear antiferromagnetic spin arrangement with and between the M1 chains. Spins on M2 sites are also antiferromagnetically coupled; however, one of the three different M1-M2 superexchange pathways within the band of M1 and M2 sites displays a ferromagnetic interaction, while the other two allow antiferromagnetic interaction. PMID:21654052

  1. Structure of the myotonic dystrophy type 2 RNA and designed small molecules that reduce toxicity.

    Science.gov (United States)

    Childs-Disney, Jessica L; Yildirim, Ilyas; Park, HaJeung; Lohman, Jeremy R; Guan, Lirui; Tran, Tuan; Sarkar, Partha; Schatz, George C; Disney, Matthew D

    2014-02-21

    Myotonic dystrophy type 2 (DM2) is an incurable neuromuscular disorder caused by a r(CCUG) expansion (r(CCUG)(exp)) that folds into an extended hairpin with periodically repeating 2×2 nucleotide internal loops (5'CCUG/3'GUCC). We designed multivalent compounds that improve DM2-associated defects using information about RNA-small molecule interactions. We also report the first crystal structure of r(CCUG) repeats refined to 2.35 Å. Structural analysis of the three 5'CCUG/3'GUCC repeat internal loops (L) reveals that the CU pairs in L1 are each stabilized by one hydrogen bond and a water-mediated hydrogen bond, while CU pairs in L2 and L3 are stabilized by two hydrogen bonds. Molecular dynamics (MD) simulations reveal that the CU pairs are dynamic and stabilized by Na(+) and water molecules. MD simulations of the binding of the small molecule to r(CCUG) repeats reveal that the lowest free energy binding mode occurs via the major groove, in which one C residue is unstacked and the cross-strand nucleotides are displaced. Moreover, we modeled the binding of our dimeric compound to two 5'CCUG/3'GUCC motifs, which shows that the scaffold on which the RNA-binding modules are displayed provides an optimal distance to span two adjacent loops. PMID:24341895

  2. The Russian oil industry re-structuration: towards the emergence of western type enterprises?

    International Nuclear Information System (INIS)

    The Russian oil industry has undergone fundamental changes since the collapse of the Soviet Empire and its bureaucratic administrative structure, dominated by its various Branch Ministries. The monopoly in the Soviet oil industry has now been replaced by a number of ''oil companies'', some of which are very powerful, the best known of them being Lukoil. These ''joint stock companies'' are the product of a reform aimed essentially at implanting, out of all the numerous organisational arrangements developed in the West, the model of the vertically integrated private firm. Beyond the legal reforms in the Russian oil industry sector, however, the nature of the organisational model that has actually emerged in Russia begs several questions. Many entities, which are complex and highly diversified, are involved in this industry. There are, of course, the many private structures in which the banks sometimes carry a considerable amount of weight. There are also some vertically integrated organisations, but the degree of integration is variable and their method of centralization is based on a specific form of economic logic. It should not be considered, however, that these actors are similar to capitalist-type private enterprises, whose behaviour is regulated by the demands of international competition. Reform of property rights has not been sufficient to create true private enterprise in Russia. (author)

  3. Structural and phase transformations in the low-temperature annealed amorphous “finemet”-type microwires

    International Nuclear Information System (INIS)

    Highlights: • Structure and magnetic properties evolution at heating of amorphous microwires was studied. • Relaxation processes in the amorphous phase correlate with an increase in Curie temperature. • Curie temperature change can not be stabilized by a prolonged exposure at pre-crystallization temperatures. • Tomographic atom probe microscopy supports the formation of ?-Fe phase precipitations enriched in Si. -- Abstract: Finemet-type glass-coated microwires with amorphous and nanocrystalline structure have been investigated. The relaxation and crystallization processes at heating of amorphous alloy have been studied by DSC method. We observed that the relaxation processes in the amorphous phase correlate with an increasing of the Curie temperature. Additionally a prolonged exposure of the samples below the crystallization temperatures does not stabilize the Curie temperature change. An investigation by the tomographic atom probe microscopy supports the formation of precipitations, probably ?-Fe phase, as a result of low-temperature annealing (400 °C, 5 min). We found that the observed nano-sized areas were enriched in silicon

  4. On the modular structure of the genus-one Type II superstring low energy expansion

    CERN Document Server

    D'Hoker, Eric; Vanhove, Pierre

    2015-01-01

    The analytic contribution to the low energy expansion of Type II string amplitudes at genus-one is a power series in space-time derivatives with coefficients that are determined by integrals of modular functions over the complex structure modulus of the world-sheet torus. These modular functions are associated with world-sheet vacuum Feynman diagrams and given by multiple sums over the discrete momenta on the torus. In this paper we exhibit exact differential and algebraic relations for a certain infinite class of such modular functions by showing that they satisfy Laplace eigenvalue equations with inhomogeneous terms that are polynomial in non-holomorphic Eisenstein series. Furthermore, we argue that the set of modular functions that contribute to the coefficients of interactions up to order D**10 R*4 are linear sums of functions in this class and quadratic polynomials in Eisenstein series and odd Riemann zeta values. Integration over the complex structure results in coefficients of the low energy expansion ...

  5. Estimation of seismic building structural types using multi-sensor remote sensing and machine learning techniques

    Science.gov (United States)

    Geiß, Christian; Aravena Pelizari, Patrick; Marconcini, Mattia; Sengara, Wayan; Edwards, Mark; Lakes, Tobia; Taubenböck, Hannes

    2015-06-01

    Detailed information about seismic building structural types (SBSTs) is crucial for accurate earthquake vulnerability and risk modeling as it reflects the main load-bearing structures of buildings and, thus, the behavior under seismic load. However, for numerous urban areas in earthquake prone regions this information is mostly outdated, unavailable, or simply not existent. To this purpose, we present an effective approach to estimate SBSTs by combining scarce in situ observations, multi-sensor remote sensing data and machine learning techniques. In particular, an approach is introduced, which deploys a sequential procedure comprising five main steps, namely calculation of features from remote sensing data, feature selection, outlier detection, generation of synthetic samples, and supervised classification under consideration of both Support Vector Machines and Random Forests. Experimental results obtained for a representative study area, including large parts of the city of Padang (Indonesia), assess the capabilities of the presented approach and confirm its great potential for a reliable area-wide estimation of SBSTs and an effective earthquake loss modeling based on remote sensing, which should be further explored in future research activities.

  6. Phosphodiesterase type IV inhibition. Structure-activity relationships of 1,3-disubstituted pyrrolidines.

    Science.gov (United States)

    Feldman, P L; Brackeen, M F; Cowan, D J; Marron, B E; Schoenen, F J; Stafford, J A; Suh, E M; Domanico, P L; Rose, D; Leesnitzer, M A

    1995-04-28

    The synthesis of 1,3-disubstituted pyrrolidines 2 and their activities as type IV phosphodiesterase (PDE) inhibitors are described. Various groups were appended to the nitrogen of the pyrrolidine nucleus to enable structure-activity relationships to be assessed. Groups which render the pyrrolidine nitrogen of 2 nonbasic yielded potent PDE-IV inhibitors. Analogs of amides, carbamates, and ureas of 2 were synthesized to determine the effects that substitution on these functional groups had on PDE-IV inhibitor potency. The structural requirements for PDE-IV inhibitor potency differed among the three classes. A representative amide, carbamate, and urea (2c,d,h) were shown to be > 50-fold selective for inhibiting PDE-IV versus representative PDEs from families I-III and V. Furthermore, these same three inhibitors demonstrated potent functional activity (IC50 < 1 microM) by inhibiting tumor necrosis factor-alpha (TNF-alpha) release from lipopolysaccharide (LPS)-activated purified human peripheral blood monocytes and mouse peritoneal macrophages. These compounds were also tested orally in LPS-injected mice and demonstrated dose-dependent inhibition of serum TNF-alpha levels. PMID:7739009

  7. Ab initio investigation of structure and stability of complex hydrides of L[MH3] type

    International Nuclear Information System (INIS)

    The structure, stability, sections of potential surfaces (PS) of NaBeH3 and LiMgH3 complex hydrides are calculated in the framework of the non-empiric Hartry-Fock-Ruthan method using the two-exponential Roos-Siegbahn basis. The extreme PS points are clarified with a more complete and flexible two-exponential Huzinada-Dunning basis and polarization. It is shown that NaBeH3, LiMgH3, as well as the formerly studied LiBeH3 complex, belong to the amount of ''globally'' tough, but ''ilocally'' nontough molecular systems. Migration barriers on the way of shifting the outerspheric cation relatively to the anion decrease in the LiBeH3-NaBeH3 series, while they rise in the LiBeH3-LiMgH3 series. The correlation between the deformation of the anion nuclear carcass and the polarization of its electronic structure under the cation effect, is stated. The nature of the chemical bond in LMH3 complexes is investigated on the basis of analyzing the composition of localized molecuar orbitals. The problems of energetic and kinetic stability of LMH3 hydrides to different types of monomolecular decomposition, are discussed

  8. Ratios of hardness numbers in calculations of static and cyclical strength of structural types of steels ??????????? ????? ????????? ? ???????? ?? ??????????? ? ??????????? ????????? ??????????????? ??????

    Directory of Open Access Journals (Sweden)

    Gustov Yuriy Ivanovich

    2013-01-01

    Full Text Available Results of calculations of values of static and cyclical strength of steels used in the structural design and based on the method of experimental and analytical coordination of hardness numbers are presented in the article. Strength measurements taken on the basis of the Rockwell method make it possible to research into the strength characteristics of small-size samples of steel in cases of restoration and inspection of the technical condition of the metalwork. Besides, the Rockwell method is universal and faster than the Brinell method.Thus, the availability of hardness values of small-size samples makes it possible to provide a definition of standard indicators of static and cyclical strength. Moreover, development of the definition of structural and power (synergetic criteria of reliability of metalsusing the equation of relative strength turn into reality. The solution to this equation ofuniform plastic deformations of dmakes it possible to identify S , S , W , W values.? B K P C The initial experimental value of the hardness number may be used to calculate avariety of static and cyclical properties of steel and to identify the standard strength group and the approximate steel type counterpart.????????? ?????????? ??????? ?? ??????????? ? ??????????? ????????? ?????? ???????????? ??????????? ?? ????????????????? ????????? ????????? HRB c ????????????? ????????? ? HB.???????? ???????????? ????? ??????? ????????? HRB ? HB ?????????? = 60 [(?RB/703 + 1]. (1?????????? ?? (1 ???? ?????????????????? ?????????? ????????? HB ?????????? HB ????????.?? ?????? ????????????????-?????????????? ???????????? HRB-HB ????? ?????????? ????????? ????????????? ???????.

  9. Ion beam irradiation effects in strontium zirconium phosphate with NZP-structure type

    Energy Technology Data Exchange (ETDEWEB)

    Gregg, Daniel J., E-mail: daniel.gregg@ansto.gov.au [Institute of Materials Engineering, Australian Nuclear Science and Technology Organisation, Locked Bag 2001, Kirrawee DC, NSW 2232 (Australia); Karatchevtseva, Inna; Thorogood, Gordon J.; Davis, Joel [Institute of Materials Engineering, Australian Nuclear Science and Technology Organisation, Locked Bag 2001, Kirrawee DC, NSW 2232 (Australia); Bell, Benjamin D.C.; Jackson, Matthew [Department of Materials, Imperial College, London SW7 2BP (United Kingdom); Dayal, Pranesh [Institute of Materials Engineering, Australian Nuclear Science and Technology Organisation, Locked Bag 2001, Kirrawee DC, NSW 2232 (Australia); Ionescu, Mihail [Institute of Environment Science, Australian Nuclear Science and Technology Organisation, Locked Bag 2001, Kirrawee DC, NSW 2232 (Australia); Triani, Gerry; Short, Ken; Lumpkin, Gregory R.; Vance, Eric R. [Institute of Materials Engineering, Australian Nuclear Science and Technology Organisation, Locked Bag 2001, Kirrawee DC, NSW 2232 (Australia)

    2014-03-15

    Ceramics with the sodium zirconium phosphate or NZP type structure have potential as nuclear waste form and inert matrix materials. For both applications the material will be subjected to self-radiation damage from ?-decay of the incorporated actinides. In this study, ion-beam irradiation using Au- and He-ions has been used to simulate the consequences of ?-decay and the effects of irradiation on the structural and macroscopic properties (density and hardness) have been investigated. Irradiation by Au-ions resulted in a significant volume contraction of ?7%, a reduction in hardness of ?30% and a loss in long-range order at fluences above 10{sup 14} Au-ions/cm{sup 2}. In contrast, little effect on the material properties was noted for samples irradiated with He-ions up to a fluence of 10{sup 17} ions/cm{sup 2}. Thermal annealing was investigated for the highest fluence Au-ion irradiated sample and significant decomposition was observed.

  10. Structure-activity relationships of polybiguanides with activity against human immunodeficiency virus type 1.

    Science.gov (United States)

    Passic, Shendra R; Ferguson, Mary Lee; Catalone, Bradley J; Kish-Catalone, Tina; Kholodovych, Vladyslav; Zhu, Wei; Welsh, William; Rando, Robert; Howett, Mary K; Wigdahl, Brian; Labib, Mohamed; Krebs, Fred C

    2010-12-01

    Previous investigations showing that polydisperse biguanide (PDBG) molecules have activity against human immunodeficiency virus type 1 (HIV-1) also suggested a relationship between PDBG biologic activity and the lengths of hydrocarbon linkers surrounding the positively charged biguanide unit. To better define structure-activity relationships, PDBG molecules with select linker lengths were evaluated for cytotoxicity, anti-HIV-1 activity, and in vivo toxicity. Results of the in vitro experiments demonstrated that increases in linker length (and, therefore, increases in compound lipophilicity) were generally associated with increases in cytotoxicity and antiviral activity against HIV-1. However, a relationship between linker length asymmetry and in vitro therapeutic index (TI) suggested structural specificity in the mechanism of action against HIV-1. Polyethylene hexamethylene biguanide (PEHMB; biguanide units spaced between alternating ethylene and hexamethylene linkers) was found to have the highest in vitro TI (CC??/IC??) among the compounds examined. Recent improvements in PEHMB synthesis and purification have yielded preparations of PEHMB with in vitro TI values of 266 and 7000 against HIV-1 strains BaL and IIIB, respectively. The minimal toxicity of PEHMB relative to polyhexamethylene biguanide (PHMB; biguanide units alternating with hexamethylene linkers) in a murine model of cervicovaginal microbicide toxicity was consistent with considerable differences in cytotoxicity between PEHMB and PHMB observed during in vitro experiments. These structure-activity investigations increase our understanding of PDBG molecules as agents with activity against HIV-1 and provide the foundation for further preclinical studies of PEHMB and other biguanide-based compounds as antiviral and microbicidal agents. PMID:21106331

  11. The structure of TeV-bright shell-type supernova remnants

    Science.gov (United States)

    Yang, Chuyuan; Liu, Siming; Fang, Jun; Li, Hui

    2015-01-01

    Aims: Two-dimensional magnetohydrodynamic (MHD) simulations are used to model the emission properties of TeV-bright shell-type supernova remnants (SNRs) and to explore their nature. Methods: In the leptonic scenario for the TeV emission, the ?-ray emission is produced via inverse Compton scattering of background soft photons by high-energy electrons accelerated by the shocks of the SNRs. In a previous paper, we showed that since the energy densities of the cosmic microwave background radiation and that of the IR/optical background photons are much higher than that of the photons produced by the same high-energy electrons via the synchrotron process, the observed correlation between X-ray and TeV brightness of SNR RX J1713.7-3946 can be readily explained with the assumption that the energy density of relativistic electrons is proportional to that of the magnetic field. The TeV emissivity is therefore proportional to the magnetic field energy density and MHD simulations can be used to model the TeV structure of such remnants directly. Two-dimensional MHD simulations for SNRs are then performed under the assumption that the ambient interstellar medium is turbulent with the magnetic field and density fluctuations, following a Kolmogorov-like power-law spectrum. Results: (1) As expected, these simulations confirm early 1D and 2D modelings of these sources, namely the hydrodynamical evolution of the shock waves and amplification of magnetic field by Rayleigh-Taylor convective flows and by shocks propagating in a turbulent medium; (2) we reproduce rather complex morphological structure for ?-rays, for example, the bright thin rim and significant asymmetry, suggesting intrinsic variations of the source morphology not related to the structure of the progenitor and environment; and (3) the observed radial profile of several remnants are well reproduced with an ambient medium density of 0.1-1 cm-3. An even lower ambient density leads to a sharper drop of the TeV brightness with radius than what is observed near the outer edge of these remnants. Conclusions: In a turbulent background medium, we can reproduce the observed characteristics of several shell-type TeV SNRs with reasonable parameters except for a higher ambient density than that inferred from X-ray observations.

  12. Structural design studies on a large pool type SFR of 1200MWe

    International Nuclear Information System (INIS)

    An economic improvement is a hot issue as one of the Gen IV nuclear plant goals. To secure economic competitiveness of a SFR compared to a pressurized water reactor, several structural design concepts are adapted in without loosing the reactor safety level. One is the increase of the plant capacity with the minimum number of component and loop, which leads the reduction of the plant maintenance, repair, and construction costs by a large-size scale effect. Another is the simple system arrangement, compact reactor size for only two loop system for a 1200MWe capacity of a pool type SFR, and the minimization of IHTS piping length through the properly locating the SG and secondary pump. Several researches are also studied to attain the economic improvement target of the NSSS in structural point of view; for example, an integrated concept of a refueling machine and inspection device with a long waveguide sensor for reactor internals. Fig.1 shows the reactor internals and components arrangement in reactor vessel. The outer diameter of the reactor vessel is 14.5m, which is very compact size compared to other designs, and 0.05m in thickness. It can accommodate the maximum core size of 7.9m. With the internal arrangement, the refueling availability of core assemblies was confirmed, and 36 control rods are supported and guided by upper internal structures. The material of reactor vessel and internal structure is a Type 316 stainless steel. The primary system consists of 4 sets ol. The primary system consists of 4 sets of primary pump, IHX, and DHX in reactor vessel. The component size is not much larger than the KALIMER-600 design because the numbers of components was increased. The reactor vessel's diameter is relatively so small that the minimum space between the components is 55cm, which may not be enough for equipment maintenance. The NSSS has two intermediate heat transport loops. The each of IHTS loops outside of the reactor vessel has 2 mechanical type pumps and 2 SGs. The fabricability of the piping and elbows of the large piping diameter was investigated for realizing this system. The piping diameters for the hot and cold legs of 80 cm and 110cm respectively are within the feasible fabrication range through the both ways of forged pipe and seamless pipe. The piping length of each loop is relatively long about 180m because of the inverse U shape piping layout adapted to the preventing the pressure propagation to the reactor vessel when a sodium-water reaction accident occurs in SG upper tube. Since this long piping layout increases the maintenance cost, the shortening of the piping total length would be necessary by properly sacrificing over-excessive safety design level. The pipe material of a Mod.9Cr-1Mo can shorten the piping length about 60m compared to stainless steel, which has also a higher mechanical strength and a low thermal expansion. This has an advantage for obtaining a simple layout of IHTS piping subjected to a high temperature environment. The two-loop system is also advantageous to a compact building size because the numbers of components can be minimized, and the total piping length could be shortened. The height of the SG is about 37.4 m. The SG tube is a double-wall straight type to reduce the possibility of the water injection to the sodium side. Two new design strategies are adapted for the economic improvement of the NSSS in structural point of view. One is an integrated component of a refueling machine and an in- service inspection (ISI) tool with a long life waveguide sensor for reactor internals. This concept will shorten the overall period of about 2 days through the reduction of in-service inspection time of Rx internals.The other is a LBB technology application for IHTS piping and RV, which will reduce the construction cost because of the unnecessary of a large scale protection facilities against to sodium leak accidents. The component arrangement and reactor structural sizing for two loop systems for a 1200MWe capacity of a SFR are suggested with several structural design improved concepts to a

  13. Systematic determination of replication activity type highlights interconnections between replication, chromatin structure and nuclear localization.

    Science.gov (United States)

    Farkash-Amar, Shlomit; David, Yaara; Polten, Andreas; Hezroni, Hadas; Eldar, Yonina C; Meshorer, Eran; Yakhini, Zohar; Simon, Itamar

    2012-01-01

    DNA replication is a highly regulated process, with each genomic locus replicating at a distinct time of replication (ToR). Advances in ToR measurement technology enabled several genome-wide profiling studies that revealed tight associations between ToR and general genomic features and a remarkable ToR conservation in mammals. Genome wide studies further showed that at the hundreds kb-to-megabase scale the genome can be divided into constant ToR regions (CTRs) in which the replication process propagates at a faster pace due to the activation of multiple origins and temporal transition regions (TTRs) in which the replication process propagates at a slower pace. We developed a computational tool that assigns a ToR to every measured locus and determines its replication activity type (CTR versus TTR). Our algorithm, ARTO (Analysis of Replication Timing and Organization), uses signal processing methods to fit a constant piece-wise linear curve to the measured raw data. We tested our algorithm and provide performance and usability results. A Matlab implementation of ARTO is available at http://bioinfo.cs.technion.ac.il/people/zohar/ARTO/. Applying our algorithm to ToR data measured in multiple mouse and human samples allowed precise genome-wide ToR determination and replication activity type characterization. Analysis of the results highlighted the plasticity of the replication program. For example, we observed significant ToR differences in 10-25% of the genome when comparing different tissue types. Our analyses also provide evidence for activity type differences in up to 30% of the probes. Integration of the ToR data with multiple aspects of chromosome organization characteristics suggests that ToR plays a role in shaping the regional chromatin structure. Namely, repressive chromatin marks, are associated with late ToR both in TTRs and CTRs. Finally, characterization of the differences between TTRs and CTRs, with matching ToR, revealed that TTRs are associated with compact chromatin and are located significantly closer to the nuclear envelope. Supplementary material is available. Raw and processed data were deposited in Geo (GSE17236). PMID:23145042

  14. Effect of annealing temperature on the structural, photoluminescence and magnetic properties of sol-gel derived Magnetoplumbite-type (M-type) hexagonal strontium ferrite

    International Nuclear Information System (INIS)

    Magnetoplumbite-type (M-type) hexagonal strontium ferrite particles were synthesized via sol-gel technique employing ethylene glycol as the gel precursor at two different calcination temperatures (800 and 1000 deg. C). Structural properties were systematically investigated via X-ray diffraction (XRD), field emission scanning electron microscopy, high resolution transmission electron microscopy (HRTEM), energy dispersive spectroscopy (EDS), thermogravimetric analysis (TGA), photoluminescence spectrophotometry and superconducting quantum interference device magnetometer. XRD results showed that the sample synthesized at 1000 deg. C was of single-phase with a space group of P63/mmc and lattice cell parameter values of a=5.882 A and c=23.048 A. EDS confirmed the composition of strontium ferrite calcined at 1000 deg. C being mainly of M-type SrFe12O19 with HRTEM micrographs confirming the ferrites exhibiting M-type long range ordering along the c-axis of the crystal structure. The photoluminescence (PL) property of strontium ferrite was examined at excitation wavelengths of 260 and 270 nm with significant PL emission peaks centered at 350 nm being detected. Strontium ferrite annealed at higher temperature (1000 deg. C) was found to have grown into larger particle size, having higher content of oxygen vacancies and exhibited 83-85% more intense PL. Both the as-prepared strontium ferrites exhibited significant oxygen vacancies defect structurgnificant oxygen vacancies defect structures, which were verified via TGA. Higher calcination temperature turned strontium ferrite into a softer ferrite. - Highlights: ? High annealing temperature produced M-type ferrite with higher oxygen vacancies. ? Photoluminescence intensity is proportional to the existence of oxygen vacancies. ? XRD data showed cell contraction well suited to the change of oxygen vacancies. ? Shift in hysteresis loop due to defect-induced exchange bias was observed.

  15. Structural safety test and analysis of type IP-2 transport packages with bolted lid type and thick steel plate for radioactive waste drums in a NPP

    International Nuclear Information System (INIS)

    If a type IP-2 transport package were to be subjected to a free drop test and a penetration test under the normal conditions of transport, it should prevent a loss or dispersal of the radioactive contents and a more than 20% increase in the maximum radiation level at any external surface of the package. In this paper, we suggested the analytic method to evaluate the structural safety of a type IP-2 transport package using a thick steel plate for a structure part and a bolt for tying a bolt. Using an analysis a loss or disposal of the radioactive contents and a loss of shielding integrity were confirmed for two kinds of type IP-2 transport packages to transport radioactive waste drums from a waste facility to a temporary storage site in a nuclear power plant. Under the free drop condition the maximum average stress at the bolts and the maximum opening displacement of a lid were compared with the tensile stress of a bolt and the steps in a lid, which were made to avoid a streaming radiation in the shielding path, to evaluate a loss or dispersal of radioactive waste contents. Also a loss of shielding integrity was evaluated using the maximum decrease in a shielding thickness. To verify the impact dynamic analysis for free drop test condition and evaluate experimentally the safety of two kinds of type IP-2 transport packages, free drop tests were conducted with various drop directions

  16. Structural Analysis of a Specialized Type III Secretion System Peptidoglycan-cleaving Enzyme.

    Science.gov (United States)

    Burkinshaw, Brianne J; Deng, Wanyin; Lameignère, Emilie; Wasney, Gregory A; Zhu, Haizhong; Worrall, Liam J; Finlay, B Brett; Strynadka, Natalie C J

    2015-04-17

    The Gram-negative bacterium enteropathogenic Escherichia coli uses a syringe-like type III secretion system (T3SS) to inject virulence or "effector" proteins into the cytoplasm of host intestinal epithelial cells. To assemble, the T3SS must traverse both bacterial membranes, as well as the peptidoglycan layer. Peptidoglycan is made of repeating N-acetylmuramic acid and N-acetylglucosamine disaccharides cross-linked by pentapeptides to form a tight mesh barrier. Assembly of many macromolecular machines requires a dedicated peptidoglycan lytic enzyme (PG-lytic enzyme) to locally clear peptidoglycan. Here we have solved the first structure of a T3SS-associated PG-lytic enzyme, EtgA from enteropathogenic E. coli. Unexpectedly, the active site of EtgA has features in common with both lytic transglycosylases and hen egg white lysozyme. Most notably, the ?-hairpin region resembles that of lysozyme and contains an aspartate that aligns with lysozyme Asp-52 (a residue critical for catalysis), a conservation not observed in other previously characterized lytic transglycosylase families to which the conserved T3SS enzymes had been presumed to belong. Mutation of the EtgA catalytic glutamate, Glu-42, conserved across lytic transglycosylases and hen egg white lysozyme, and this differentiating aspartate diminishes type III secretion in vivo, supporting its essential role in clearing the peptidoglycan for T3SS assembly. Finally, we show that EtgA forms a 1:1 complex with the building block of the polymerized T3SS inner rod component, EscI, and that this interaction enhances PG-lytic activity of EtgA in vitro, collectively providing the necessary strict localization and regulation of the lytic activity to prevent overall cell lysis. PMID:25678709

  17. Radiation stimulated effects in crystals of quartz and berlinit with different type and degree of perfection structure

    CERN Document Server

    Ibragimov, Z D

    2001-01-01

    of structure. The effectiveness of creation of additional defects near defects of one type is increased with growth of concentration of other types of structure violations. It was established that in crystals of quartz and berlinit alpha-beta-transition during neutron irradiation occurs through formation of seeds of beta-phase. It was shown that the grown layer with beta-phase inherited also neutron induced defects of alpha-phase as well as defects related to beta-phase of quartz. The structure of amorphous phase formed around seeds of beta-phase differs from quartz glass structure. The formation of regions with structure closed to quartz glass structure occurs after definite neutron fluence values. In quartz crystals there are several defect centers emitting in red spectral range. The processes of impact and non-impact production of point defects, mechanisms of structure transformations in quartz and berlinit crystals irradiated by various types of radiation with over- and sub- threshold energy were studied....

  18. Structural insights into thyroid hormone transport mechanisms of the L-type amino Acid transporter 2.

    Science.gov (United States)

    Hinz, Katrin M; Meyer, Katja; Kinne, Anita; Schülein, Ralf; Köhrle, Josef; Krause, Gerd

    2015-06-01

    Thyroid hormones (THs) are transported across cell membranes by different transmembrane transporter proteins. In previous studies, we showed marked 3,3'-diiodothyronine (3,3'-T2) but moderate T3 uptake by the L-type amino acid transporter 2 (Lat2). We have now studied the structure-function relationships of this transporter and TH-like molecules. Our Lat2 homology model is based on 2 crystal structures of the homologous 12-transmembrane helix transporters arginine/agmatine antiporter and amino acid/polyamine/organocation transporter. Model-driven mutagenesis of residues lining an extracellular recognition site and a TH-traversing channel identified 9 sensitive residues. Using Xenopus laevis oocytes as expression system, we found that side chain shortening (N51S, N133S, N248S, and Y130A) expanded the channel and increased 3,3'-T2 transport. Side chain enlargements (T140F, Y130R, and I137M) decreased 3,3'-T2 uptake, indicating channel obstructions. The opposite results with mutations maintaining (F242W) or impairing (F242V) uptake suggest that F242 may have a gating function. Competitive inhibition studies of 14 TH-like compounds revealed that recognition by Lat2 requires amino and carboxylic acid groups. The size of the adjacent hydrophobic group is restricted. Bulky substituents in positions 3 and 5 of the tyrosine ring are allowed. The phenolic ring may be enlarged, provided that the whole molecule is flexible enough to fit into the distinctly shaped TH-traversing channel of Lat2. Taken together, the next Lat2 features were identified 1) TH recognition site; 2) TH-traversing channel in the center of Lat2; and 3) switch site that potentially facilitates intracellular substrate release. Together with identified substrate features, these data help to elucidate the molecular mechanisms and role of Lat2 in T2 transport. PMID:25945809

  19. Structure of the C-type lectin carbohydrate recognition domain of human tetranectin

    DEFF Research Database (Denmark)

    Kastrup, J S; Nielsen, B B

    1998-01-01

    Tetranectin (TN) is a C-type lectin involved in fibrinolysis, being the only endogenous ligand known to bind specifically to the kringle 4 domain of plasminogen. TN was originally isolated from plasma, but shows a wide tissue distribution. Furthermore, TN has been found in the extracellular matrix of certain human carcinomas, whereas none or little is present in the corresponding normal tissue. The crystal structure of full-length trimeric TN (2.8 A resolution) has recently been published [Nielsen et al. (1997). FEBS Lett. 412, 388-396]. The crystal structure of the carbohydrate recognition domain (CRD) of human TN (TN3) has been determined separately at 2.0 A resolution in order to obtain detailed information on the two calcium binding sites. This information is essential for the elucidation of the specificity of TN towards oligosaccharides. TN3 crystallizes as a dimer, whereas it appears as a monomer in solution. The overall fold of TN3 is similar to other known CRDs. Each monomer is built of two distinct regions, one region consisting of six beta-strands and two alpha-helices, and the other region is composed of four loops harboring two calcium ions. The calcium ion at site 1 forms an eightfold coordinated complex and has Asp116, Glu120, Gly147, Glu150, Asn151, and one water molecule as ligands. The calcium ion at site 2, which is believed to be involved in recognition and binding of oligosaccharides, is sevenfold coordinated with ligands Gln143, Asp145, Glu150, Asp165, and two water molecules. One sulfate ion has been located at the surface of TN3, forming contacts to Glu120, Lys148, Asn106 of a symmetry-related molecule, and to an ethanol molecule.

  20. Monazite-type ceramics for conditioning of minor actinides. Structural characterization and properties

    Energy Technology Data Exchange (ETDEWEB)

    Babelot, Carole

    2013-07-01

    The minor actinides (MA) neptunium, americium, and curium are mainly responsible for the long-term radiotoxicity of the High Active Waste (HAW) generated during the nuclear power operation. If these long-lived radionuclides are removed from the HAW by partitioning and converted by neutron fission (transmutation) into shorter-lived or stable elements, the remaining waste loses most of its long-term radiotoxicity. Thus, partitioning and transmutation (P and T) are considered as attractive options for reducing the burden on geological disposals. As an alternative, these separated MA can also be conditioned (P and C strategy) in specifically adapted ceramics to ensure their safe final disposal over long periods. At the moment, spent fuel elements are foreseen either for direct disposal in deep geological repositories or for reprocessing. The highly active liquid waste that is produced during reprocessing is conditioned industrially using a vitrification process before final disposal. Although the widely used borosilicate glasses meet most of the specifications needed, ceramic host matrices appear to be even more suitable in terms of resistance to corrosion. The development of new materials based on tailor-made highly specific ceramics with extremely stable behavior would make it possible to improve the final storage of long-lived high-level radiotoxic waste. In the framework of this PhD research project, monazite-type ceramics were chosen as promising host matrices for the conditioning of trivalent actinides. The focus on the monazite-type ceramics is justified by their properties such as high chemical durability. REPO{sub 4} ceramics are named monazite for RE = La - Gd (monoclinic symmetry) and xenotime for RE = Tb - Lu and Y (tetragonal symmetry). The objective of this study is to contribute to the understanding of the alteration behavior of such ceramics under the repository conditions. REPO{sub 4} (with RE = La, Eu) is prepared by hydrothermal synthesis at 200 C. Structural and morphological characteristics (using X-ray diffraction (XRD) and scanning electron microscope (SEM)) combined with physical and thermal properties of samples (using thermogravimetry, differential scanning calorimetry (TG-DSC) and dilatometry) are realized in order to study the behavior of monazite-type powder and pellets. The access to short-range-order spectroscopy (time resolved laser fluorescence spectroscopy (TRLFS) and extended X-ray absorption fine structure (EXAFS)) permits to understand the structure of ceramic waste forms at the molecular level. La-monazite matrices being doped with Eu (III) (as a non-radioactive chemical homologue for Am (III)) and Cm (III), TRLFS is used to explore the local structural environment of Eu and Cm within the monazite crystal structure. Eu (III) and Cm (III) are substituted on the La site of LaPO{sub 4}. The single site of Cm (III) is found in four slightly different environments which is assumed to be due to a difference in the four La sites within a LaPO4 unit cell. Structural parameters of the Eu (III) species were also analyzed by EXAFS. The nearest neighbors of Eu (III) are modeled as 9.5 oxygen atoms (N{sub O1} = 4 at r(EuO1) = 2.37 Aa, N{sub O2} = 4 at r(Eu-O2) = 2.53 Aa, and N{sub O3} = 1.5 at r(Eu-O3) = 2.83 Aa). An essential parameter that describes the stability of the host phases is their dissolution rate obtained under conditions of relevance for final repositories. In this context, a set-up is developed and tested on crushed pellets. Normalized weight losses of lanthanumphosphates and europium-doped lanthanum-phosphates, measured in acidic media at 90 C, are interpreted and compared against the previous findings from the literature. The normalized dissolution rate for La and Eu within (La, Eu)PO{sub 4} is between 1.10{sup -5} and 1.10{sup -4} g.m{sup -2}.d{sup -1}, whereas the rate of Na, Cs and Sr in phosphate glass at room temperature in deionized water is about 1.10{sup -2} g.m{sup -2}.d{sup -1}. Another essential parameter is their resistance to radiation. The damage created by the recoils

  1. Monazite-type ceramics for conditioning of minor actinides. Structural characterization and properties

    International Nuclear Information System (INIS)

    The minor actinides (MA) neptunium, americium, and curium are mainly responsible for the long-term radiotoxicity of the High Active Waste (HAW) generated during the nuclear power operation. If these long-lived radionuclides are removed from the HAW by partitioning and converted by neutron fission (transmutation) into shorter-lived or stable elements, the remaining waste loses most of its long-term radiotoxicity. Thus, partitioning and transmutation (P and T) are considered as attractive options for reducing the burden on geological disposals. As an alternative, these separated MA can also be conditioned (P and C strategy) in specifically adapted ceramics to ensure their safe final disposal over long periods. At the moment, spent fuel elements are foreseen either for direct disposal in deep geological repositories or for reprocessing. The highly active liquid waste that is produced during reprocessing is conditioned industrially using a vitrification process before final disposal. Although the widely used borosilicate glasses meet most of the specifications needed, ceramic host matrices appear to be even more suitable in terms of resistance to corrosion. The development of new materials based on tailor-made highly specific ceramics with extremely stable behavior would make it possible to improve the final storage of long-lived high-level radiotoxic waste. In the framework of this PhD research project, monazite-type ceramics were chosen as promising host matrices for the conditioning of trivalent actinides. The focus on the monazite-type ceramics is justified by their properties such as high chemical durability. REPO4 ceramics are named monazite for RE = La - Gd (monoclinic symmetry) and xenotime for RE = Tb - Lu and Y (tetragonal symmetry). The objective of this study is to contribute to the understanding of the alteration behavior of such ceramics under the repository conditions. REPO4 (with RE = La, Eu) is prepared by hydrothermal synthesis at 200 C. Structural and morphological characteristics (using X-ray diffraction (XRD) and scanning electron microscope (SEM)) combined with physical and thermal properties of samples (using thermogravimetry, differential scanning calorimetry (TG-DSC) and dilatometry) are realized in order to study the behavior of monazite-type powder and pellets. The access to short-range-order spectroscopy (time resolved laser fluorescence spectroscopy (TRLFS) and extended X-ray absorption fine structure (EXAFS)) permits to understand the structure of ceramic waste forms at the molecular level. La-monazite matrices being doped with Eu (III) (as a non-radioactive chemical homologue for Am (III)) and Cm (III), TRLFS is used to explore the local structural environment of Eu and Cm within the monazite crystal structure. Eu (III) and Cm (III) are substituted on the La site of LaPO4. The single site of Cm (III) is found in four slightly different environments which is assumed to be due to a difference in the four La sites within a LaPO4 unit cell. Structural parameters of the Eu (III) species were also analyzed by EXAFS. The nearest neighbors of Eu (III) are modeled as 9.5 oxygen atoms (NO1 = 4 at r(EuO1) = 2.37 Aa, NO2 = 4 at r(Eu-O2) = 2.53 Aa, and NO3 = 1.5 at r(Eu-O3) = 2.83 Aa). An essential parameter that describes the stability of the host phases is their dissolution rate obtained under conditions of relevance for final repositories. In this context, a set-up is developed and tested on crushed pellets. Normalized weight losses of lanthanumphosphates and europium-doped lanthanum-phosphates, measured in acidic media at 90 C, are interpreted and compared against the previous findings from the literature. The normalized dissolution rate for La and Eu within (La, Eu)PO4 is between 1.10-5 and 1.10-4 g.m-2.d-1, whereas the rate of Na, Cs and Sr in phosphate glass at room temperature in deionized water is about 1.10-2 g.m-2.d-1. Another essential parameter is their resistance to radiation. The damage created by the recoils accompanying alpha-decay can be simulated on ceramic matrices. Preliminary experimen

  2. Structure and properties of HS6-5-2 type HSS manufactured by different P/M methods

    OpenAIRE

    Matula, G.; L.A. Dobrza?ski; G. Herranz; A. Varez; B. Levenfeld; J.M. Torralba

    2007-01-01

    Purpose: It has been demonstrated in the paper structure and properties of of high speed-steel HS6-5-2 type manufactured by different method of powder metallurgy.Design/methodology/approach: Light microscope, SEM, image analysis, hardness tests, density examination, transverse rupture strength tests, analysis of chemical composition by LECO apparatus.Findings: Basing on the investigations of the HS6-5-2 type high-speed steels reinforced with ceramics particles fabricated with Powder Met...

  3. Radio Structures of Seyfert Galaxies. VIII. A Distance and Magnitude Limited Sample of Early-Type Galaxies

    OpenAIRE

    Nagar, Neil M.; Wilson, Andrew S.; Mulchaey, John S.; Gallimore, Jack F.

    1999-01-01

    The VLA has been used at 3.6 and 20 cm to image a sample of about 50 early-type Seyfert galaxies with recessional velocities less than 7,000 km/s and total visual magnitude less than 14.5. The nuclear radio structures of Seyfert 2.0's in the early-type sample tend to be aligned with the [OIII] and Halpha+[NII] structures even though the radio extents are smaller than the [OIII] and Halpha+[NII] extents by a factor of ~2->5. This alignment, previously known for individual Sey...

  4. Influence of Rotor Structure and Number of Phases on First and Second Order Characteristics of TOYOTA PRIUS Electrical Machine Type

    OpenAIRE

    Aslan, Bassel; Korecki, Julien; Vigier, Thimote?; Semail, Eric

    2011-01-01

    This paper investigates the influence of the rotor structure on torque and Flux weakening region of V-shape IPM machine from TOYOTA PRIUS type, more specifically, keeping always the same magnet volume, we study the effect of the open angle between the two magnet segments of each V-shape pole on the machine performance. Moreover, in order to examine the impact of phase number on the machine characteristics, PRIUS structure is transformed into 5-phase machine of the same type and dimensions. As...

  5. A weak link type structure for an Ag/Y1Ba2Cu3O7-y contact

    International Nuclear Information System (INIS)

    This paper reports on silver paint sintered contacts on Y1Ba2Cu3O7-y ceramic superconductors that have given rise to contact s with an I-V characteristics that reveals a nonohmic and sintering dependent behavior. They exhibit a tail regime (dV2/dI2), even for currents that are lower than the critical bulk even for currents that are lower than the critical bulk critical current. Such behavior may be a consequence of a weak-link type structure for the interface. Ic-T measurements reveal in accordance with this, the formation of some type of 123-Ag-123 proximity structure

  6. Structure and property investigations of spinel type LiMnTiO4

    International Nuclear Information System (INIS)

    Spinel type LiMn204 was considered an attractive cathode material for rechargeable lithium ion batteries. Doping of LiMn204 with tetravalent titanium was proposed in order to improve the capacity and charge-discharge capability. Since the first study of LiMnTiO4 in 1986, there has been an ongoing debate on the metal ion ordering in the structure. Most recently Arillo et al. reported a comprehensive study on the effect of different sintering temperatures and cooling regimes on the structure and metal ion ordering of LiMnTiO4. They concluded that Li=+Ti4[Li+Mn3+Ti4+]04 (Fd3m), where square brackets denote the octahedral sites, was formed upon slow cooling. Whereas Li+Mn2+[Li+Mn3+/4+Ti4+]04 (P4332) was formed alongside the main F3m phase upon quenching. In this contribution, LiMnTiO4 compounds were prepared through solid state synthesis with two cooling regimes: quenching in liquid N2 and slow cooling. Synchrotron X-ray and neutron powder diffraction refinements presented the quenched LiMnTiO4 as spinel (Fd3m) with cation distribution of Li0.65TiO.35[Li0.35MnTi0.65]04, whilst partial phase transition from Fd3m to P4332 occurred on slow cooling of LiMnTiO4, contradicting Arillo et al. The metal ion occupancy of the P4332 phase was not able to be refined due to the relatively small amount present. Magnetic field dependence measurements of the compounds indicated that Mn3+ contributed to the effective moment predominantly. Mn and Ti K edge X-ray absorption near edge structure spectra revealed the presence of Mn3+ and Ti4+ on the octahedral sites for LiMnTiO4, regardless of the cooling regimes. This combination of magnetic measurements and XANES data further contradicts the metal ion ordering found by Arillo et al.

  7. Crystal structure of a Xenopus laevis skin proto-type galectin, close to but distinct from galectin-1.

    Science.gov (United States)

    Nonaka, Yasuhiro; Ogawa, Takashi; Yoshida, Hiromi; Shoji, Hiroki; Nishi, Nozomu; Kamitori, Shigehiro; Nakamura, Takanori

    2015-07-01

    Xenopus laevis (African clawed frog) has two types of proto-type galectins that are similar to mammalian galectin-1 in amino acid sequence. One type, comprising xgalectin-Ia and -Ib, is regarded as being equivalent to galectin-1, and the other type, comprising xgalectin-Va and -Vb, is expected to be a unique galectin subgroup. The latter is considerably abundant in frog skin; however, its biological function remains unclear. We determined the crystal structures of two proto-type galectins, xgalectin-Ib and -Va. The structures showed that both galectins formed a mammalian galectin-1-like homodimer, and furthermore, xgalectin-Va formed a homotetramer. This tetramer structure has not been reported for other galectins. Gel filtration and other experiments indicated that xgalectin-Va was in a dimer-tetramer equilibrium in solution, and lactose binding enhanced the tetramer formation. The residues involved in the dimer-dimer association were conserved in xgalectin-Va and -Vb, and one of the Xenopus (Silurana) tropicalis proto-type galectins, but not in xgalectin-Ia and -Ib, and other galectin-1-equivalent proteins. Xgalectin-Va preferred Gal?1-3GalNAc and not Gal?1-4GlcNAc, while xgalectin-Ib preferred Gal?1-4GlcNAc as well as human galectin-1. Xgalectin-Va/Vb would have diverged from the galectin-1 group with accompanying acquisition of the higher oligomer formation and altered ligand selectivity. PMID:25804418

  8. Precision measurements of large scale structure with future type Ia supernova surveys

    CERN Document Server

    Hannestad, Steen; Thomsen, Bjarne

    2007-01-01

    Type Ia supernovae are currently the best known standard candles at cosmological distances. In addition to providing a powerful probe of dark energy they are an ideal source of information about the peculiar velocity field of the local universe. Even with the very small number of supernovae presently available it has been possible to measure the dipole and quadrupole of the local velocity field out to z~0.025. With future continuous all-sky surveys like the LSST project the luminosity distances of tens of thousands of nearby supernovae will be measured accurately. This will allow for a determination of the local velocity structure of the universe as a function of redshift with unprecedented accuracy, provided the redshifts of the host galaxies are known. Using catalogues of mock surveys we estimate that future low redshift supernova surveys will be able to probe sigma-8 to a precision of roughly 5% at 95% C.L. This is comparable to the precision in future galaxy and weak lensing surveys and with a relatively ...

  9. Probing the 2-D kinematic structure of early-type galaxies out to 3 effective radii

    CERN Document Server

    Proctor, Robert N; Romanowsky, Aaron J; Brodie, Jean P; Strader, Jay; Spolaor, Max; Mendel, J Trevor; Spitler, Lee

    2009-01-01

    We detail an innovative new technique for measuring the 2-D velocity moments (rotation velocity, velocity dispersion and Gauss-Hermite coefficients h$_3$ and h$_4$) of the stellar populations of galaxy halos using spectra from Keck DEIMOS multi-object spectroscopic observations. The data are used to reconstruct 2-D rotation velocity maps. Here we present data for five nearby early-type galaxies to ~3 effective radii. We provide significant insights into the global kinematic structure of these galaxies, and challenge the accepted morphological classification in several cases. We show that between 1-3 effective radii the velocity dispersion declines very slowly, if at all, in all five galaxies. For the two galaxies with velocity dispersion profiles available from planetary nebulae data we find very good agreement with our stellar profiles. We find a variety of rotation profiles beyond 1 effective radius, i.e rotation speed remaining constant, decreasing \\emph{and} increasing with radius. These results are of pa...

  10. Structure-activity studies reveal two allatostatin receptor types in corpora allata of Diploptera punctata.

    Science.gov (United States)

    Feyereisen, R; Siegel, N R.; Fok, K F.; Chandran Unnithan, G; Pratt, G E.

    1997-07-01

    Synthetic variants of the octadecapeptide amide ASB2 (AYSYVSEYKRLPVYNFGL-NH(2)), a cockroach allatostatin, were assayed in vitro on corpora allata (CA) from 2-day-old (vitellogenic) and 10-day-old (post-vitellogenic) female Diploptera punctata. The analogs [(17)psi(18),CH(2)-S]ASB2, [D-Trp(17)]ASB2 and [Ile(18)]ASB2 inhibited juvenile hormone (JH) synthesis with simple dose-response curves on sensitive CA from 10-day-old females. These analogs were fully effective but less potent than ASB2. When tested on CA from 2-day-old mated females, which are only partially (65-70%) sensitive to ASB2, the three analogs gave biphasic dose-response curves and elicited a maximal effect only at higher concentrations. The dose-response curve for ASB2 on CA from 2-day-old females had a Hill plot slope of only 0.78+/-0.03. These findings suggested that the observed CA sensitivity to ASB2 may be the result of two partial responses having an IC(50) of approximately 0.35 and 3nM respectively. One partial response, or receptor type, appeared more sensitive than the other to adverse modification of the "message" segment of the peptide. The activity of shorter allatostatins was also studied, indicating that pentapeptides of the YXFGL-amide structure are fully effective, albeit at low potency, as inhibitors of JH biosynthesis. PMID:12769973

  11. The structure of TeV-bright shell-type supernova remnants

    CERN Document Server

    Yang, Chuyuan; Fang, Jun; Li, Hui

    2014-01-01

    Aims. Two-dimensional MHD simulations are used to model the emission properties of TeV-bright shell-type supernova remnants (SNRs) and to explore their nature. Methods. In the leptonic scenario for the TeV emission, the $\\gamma$-ray emission is produced via Inverse Compton scattering of background soft photons by high-energy electrons accelerated by the shocks of the SNRs. The TeV emissivity is proportional to the magnetic field energy density and MHD simulations can be used to model the TeV structure of such remnants directly. 2D MHD simulations for SNRs are then performed under the assumption that the ambient interstellar medium is turbulent with the magnetic field and density fluctuations following a Kolmogorov-like power-law spectrum. Results. (1) As expected, these simulations confirm early 1D and 2D modelings of these sources, namely the hydrodynamical evolution of the shock waves and amplification of magnetic field by Rayleigh-Taylor convective flows and by shocks propagating in a turbulent medium; (2)...

  12. Theory of carrier electronic structure and some related quantities of n-type SnTe

    International Nuclear Information System (INIS)

    We present a theory of the electronic structure calculation for SnTe, based on a k-vector . ?-vector method (?-vector being the momentum operator in the presence of the spin–orbit interaction). The calculation envisages a six-level basis for the energy states at the L-point of the Brillouin zone. The k-vector . ?-vector Hamiltonians for the band-edge states are diagonalized exactly, and the far bands are treated using second-order perturbation theory. We obtain non-parabolic dispersion for the carriers. We calculate the Fermi energy, the density of states, the effective mass and the g-factors using the cylindrical coordinate system for the k-vector-space integration wherever occurring. All these quantities are calculated and studied as functions of carrier concentration for n-type SnTe. We could not compare our carrier-concentration-dependent quantities with some experimental parameters due to unavailability, but the extrapolated band-edge values of the effective masses and the g-factors agree fairly well with the values obtained by previous calculations. In view of the recent interest in the carrier-induced magnetism in semiconductors, our values would be of interest to both theorists and experimentalists

  13. A class of scale-free networks with fractal structure based on subshift of finite type

    Science.gov (United States)

    Chen, Jin; Dai, Meifeng; Wen, Zhixiong; Xi, Lifeng

    2014-12-01

    In this paper, given a time series generated by a certain dynamical system, we construct a new class of scale-free networks with fractal structure based on the subshift of finite type and base graphs. To simplify our model, we suppose the base graphs are bipartite graphs and the subshift has the special form. When embedding our growing network into the plane, we find its image is a graph-directed self-affine fractal, whose Hausdorff dimension is related to the power law exponent of cumulative degree distribution. It is known that a large spectral gap in terms of normalized Laplacian is usually associated with small mixing time, which makes facilitated synchronization and rapid convergence possible. Through an elaborate analysis of our network, we can estimate its Cheeger constant, which controls the spectral gap by Cheeger inequality. As a result of this estimation, when the bipartite base graph is complete, we give a sharp condition to ensure that our networks are well-connected with rapid mixing property.

  14. Physical properties of new cerium palladium phosphide with C6Cr23-type structure

    Directory of Open Access Journals (Sweden)

    T. Abe

    2014-01-01

    Full Text Available We have found that a cerium palladium phosphide crystallizes into a C6Cr23-type structure with atomic disorder. Prepared polycrystalline samples show a homogeneity range in the ternary Ce–Pd–P phase diagram. The physical properties of the highest-quality sample of Ce2.4Pd20.7P5.9 were investigated by measuring the magnetization, electrical resistivity and specific heat. No pronounced phase transition was observed down to 0.5 K. The Kondo screening of localized 4f electrons in metallic Ce2.4Pd20.7P5.9 appears to be weaker than that in the isostructural compounds of Ce3Pd20Si6 and Ce3Pd20Ge6. By a comparative study of Ce2.4Pd20.7P5.9 and Ce3Pd20X6 (X = Si, Ge, the competition between the Kondo temperature and ordering temperatures including the quadrupolar ordering temperature is briefly discussed.

  15. Structure and evolution of low-mass W UMa type systems -- II. with angular momentum loss

    CERN Document Server

    Li, L; Zhang, F

    2004-01-01

    In a preceding paper, using Eggleton's evolution code we have discussed the structure and evolution of low-mass W UMa type contact binaries without angular momentum loss (AML). The models exhibit cyclic behavior about a state of marginal contact on a thermal time-scale. Part of the time of each cycle is spent in contact and part in a semi-detached state. According to observations, W UMa systems suffer AML. We present the models of low-mass contact binaries with AML due to gravitational wave radiation (GR) or magnetic stellar wind (MSW) are presented. We find that gravitational radiation cannot prevent the cyclic evolution of W UMa systems, and the effect of gravitational radiation on the cyclic behavior of contact binary evolution is almost negligible. We also find that the most likely AML mechanism for W UMa systems is magnetic braking, and that magnetic braking effects can increase the period of the cyclic evolution, and shorten the fraction of the time spent in the poor thermal contact state. If W UMa star...

  16. Structure–performance relationships for cantilever-type piezoelectric energy harvesters

    International Nuclear Information System (INIS)

    This study provides comprehensive analysis of the structure–performance relationships in cantilever-type piezoelectric energy harvesters. It provides full understanding of the effect of all the practical global control variables on the harvester performance. The control variables considered for the analysis were material parameters, areal and volumetric dimensions, and configuration of the inactive and active layers. Experimentally, the output power density of the harvester was maximum when the shape of the beam was close to a square for a constant bending stiffness and a fixed beam area. Through analytical modeling of the effective stiffness for the piezoelectric bimorph, the conditions for enhancing the bending stiffness within the same beam volume as that of a conventional bimorph were identified. The harvester configuration with beam aspect ratio of 0.86 utilizing distributed inactive layers exhibited an giant output power of 52.5?mW and power density of 28.5?mW?cm?3 at 30?Hz under 6.9?m?s?2 excitation. The analysis further indicates that the trend in the output power with varying damping ratio is dissimilar to that of the efficiency. In order to realize best performance, the harvester should be designed with respect to maximizing the magnitude of output power.

  17. Structure-performance relationships for cantilever-type piezoelectric energy harvesters

    Science.gov (United States)

    Cho, Kyung-Hoon; Park, Hwi-Yeol; Heo, Jin S.; Priya, Shashank

    2014-05-01

    This study provides comprehensive analysis of the structure-performance relationships in cantilever-type piezoelectric energy harvesters. It provides full understanding of the effect of all the practical global control variables on the harvester performance. The control variables considered for the analysis were material parameters, areal and volumetric dimensions, and configuration of the inactive and active layers. Experimentally, the output power density of the harvester was maximum when the shape of the beam was close to a square for a constant bending stiffness and a fixed beam area. Through analytical modeling of the effective stiffness for the piezoelectric bimorph, the conditions for enhancing the bending stiffness within the same beam volume as that of a conventional bimorph were identified. The harvester configuration with beam aspect ratio of 0.86 utilizing distributed inactive layers exhibited an giant output power of 52.5 mW and power density of 28.5 mW cm-3 at 30 Hz under 6.9 m s-2 excitation. The analysis further indicates that the trend in the output power with varying damping ratio is dissimilar to that of the efficiency. In order to realize best performance, the harvester should be designed with respect to maximizing the magnitude of output power.

  18. Structure–performance relationships for cantilever-type piezoelectric energy harvesters

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Kyung-Hoon, E-mail: kh97.cho@samsung.com, E-mail: spriya@vt.edu; Park, Hwi-Yeol; Heo, Jin S. [Samsung Advanced Institute of Technology, Samsung Electronics, Yongin 446-712 (Korea, Republic of); Priya, Shashank, E-mail: kh97.cho@samsung.com, E-mail: spriya@vt.edu [Center for Energy Harvesting Materials and Systems (CEHMS), Virginia Tech, Virginia 24061 (United States)

    2014-05-28

    This study provides comprehensive analysis of the structure–performance relationships in cantilever-type piezoelectric energy harvesters. It provides full understanding of the effect of all the practical global control variables on the harvester performance. The control variables considered for the analysis were material parameters, areal and volumetric dimensions, and configuration of the inactive and active layers. Experimentally, the output power density of the harvester was maximum when the shape of the beam was close to a square for a constant bending stiffness and a fixed beam area. Through analytical modeling of the effective stiffness for the piezoelectric bimorph, the conditions for enhancing the bending stiffness within the same beam volume as that of a conventional bimorph were identified. The harvester configuration with beam aspect ratio of 0.86 utilizing distributed inactive layers exhibited an giant output power of 52.5?mW and power density of 28.5?mW?cm{sup ?3} at 30?Hz under 6.9?m?s{sup ?2} excitation. The analysis further indicates that the trend in the output power with varying damping ratio is dissimilar to that of the efficiency. In order to realize best performance, the harvester should be designed with respect to maximizing the magnitude of output power.

  19. Resistance of structure and antigenic determinations of native hexon of type 1 adenovirus to protease

    International Nuclear Information System (INIS)

    Native hexon capsomers (trimers) of human type 1 adenovirus (Ad hl) were labeled with 125I and subjected to cleavage by trypsin, chymotrypsin, and papain. The hydrolysis of the hexon of Ad 1 by these enzymes is limited and in each case a set of relatively large fragments, which are not cleaved during prolonged hydrolysis, is formed. The degree of hydrolysis of the Ad hl hexon increases in the order trypsin < chymotrypsin < papain, the molecular weight of the largest fragments constituting 80,000, 40,000, and 32,000, respectively. At a decreased temperature all the large fragments of the hydrolysates obtained are confined in aggregates (the cores of the hexon), similar in structure to the original hexon trimers, the papain core of the Ad hl hexon being the most stable during electrophoresis in polyacrylamide gel and the chymotrypsin core being the least. A radioimmunoprecipitation analysis showed that denatured fragments of the tryptic, chymotryptic, and papain hydrolysates do not possess antigenic activity

  20. Enzymatic and structural characterization of type II isopentenyl diphosphate isomerase from hyperthermophilic archaeon Thermococcus kodakaraensis

    International Nuclear Information System (INIS)

    Enzymatic and thermodynamic characteristics of type II isopentenyl diphosphate (IPP):dimethylallyl diphosphate (DMAPP) isomerase (Tk-IDI) from Thermococcus kodakaraensis, which catalyzes the interconversion of IPP and DMAPP, were examined. FMN was tightly bound to Tk-IDI, and the enzyme required NADPH and Mg2+ for the isomerization in both directions. The melting temperature (Tm), the change of enthalpy (?Hm), and the heat capacity change (?Cp) of Tk-IDI were 88.0 deg C, 444 kJ mol-1, and 13.2 kJ mol-1 K-1, respectively, indicating that Tk-IDI is fairly thermostable. Kinetic parameters dramatically changed when the temperature crossed 80 deg C even though its native overall structure was stably maintained up to 90 deg C, suggesting that local conformational change would occur around 80 deg C. This speculation was supported by the result of the circular dichroism analysis that showed the shift of the ?-helical content occurred at 80 deg C

  1. Structural analysis of piping after a large pipe break in a WWER-440 type reactor

    International Nuclear Information System (INIS)

    In the WWER-440 reactor the primary piping consists of six horizontal loops going radially from the pressure vessel, each loop having a horizontal steam generator. In this reactor type the relatively long primary piping with many curved sections requires special attention in order to successfully eliminate the consequences of the design basis accident. Emergency supports are located in appropriate places to restrict the movements of the pipe in 1, 2, 3 or 4 directions depending on the geometry of the pipe near the support. Under normal conditions there is a gap of some centimeters between the pipe and a support so that the pipe can be deformed freely under changing loads. In order to analyse the behaviour of the broken piping system with the support structures a computer code called PIPEBREAK has been written. The main objects in the analyses have been to calculate the deformations of the supports and to evaluate the stresses in the pipe. The results indicate that the stresses during the pipe whipping in the pipe exceeded the static yielding point of the material, but the time intervals during which the yielding point is exceeded are short. (Auth.)

  2. A class of scale-free networks with fractal structure based on subshift of finite type.

    Science.gov (United States)

    Chen, Jin; Dai, Meifeng; Wen, Zhixiong; Xi, Lifeng

    2014-12-01

    In this paper, given a time series generated by a certain dynamical system, we construct a new class of scale-free networks with fractal structure based on the subshift of finite type and base graphs. To simplify our model, we suppose the base graphs are bipartite graphs and the subshift has the special form. When embedding our growing network into the plane, we find its image is a graph-directed self-affine fractal, whose Hausdorff dimension is related to the power law exponent of cumulative degree distribution. It is known that a large spectral gap in terms of normalized Laplacian is usually associated with small mixing time, which makes facilitated synchronization and rapid convergence possible. Through an elaborate analysis of our network, we can estimate its Cheeger constant, which controls the spectral gap by Cheeger inequality. As a result of this estimation, when the bipartite base graph is complete, we give a sharp condition to ensure that our networks are well-connected with rapid mixing property. PMID:25554053

  3. Five types of polyurethane vascular grafts in dogs: the importance of structural design and material selection.

    Science.gov (United States)

    Xie, Xingyi; Eberhart, Andreas; Guidoin, Robert; Marois, Yves; Douville, Yvan; Zhang, Ze

    2010-01-01

    Five polyurethane vascular grafts with three different chemistries were investigated in terms of device function, healing characteristics and material stability in a canine abdominal aorta model for prescheduled periods of 1 and 6 months. Corvita-reinforced grafts, with walls made of poly(carbonate urethane) (PCU) filaments, displayed a relatively thin, uniform and partially endothelialized inner capsule with good tissue in-growth. The external polyester mesh separated from the underlying PCU wall due to the degradation of the melt adhesive between these two layers. Three types of Thoratec access graft exhibited a high degree of thrombus and little tissue in-growth, and were non-adhesive to both the inner and external capsules as the solid layer beneath their lumens completely blocked any transmural communication. The microporous poly(ether urethane urea) degraded extensively. Pulse-Tec grafts at one month also demonstrated non-adhesive properties because the external skin served as a barrier to tissue in-growth. At 6 months, its poly(ether urethane) wall displayed the most severe degradation, damaging graft structural integrity and causing significant tissue deposition in the degradation areas. This study shows the importance of multiple factors in vascular prosthesis design and demonstrates that collective and comprehensive thinking will be key in the future development of creative and novel approaches. PMID:20507718

  4. Modeling and simulation of a Stewart platform type parallel structure robot

    Science.gov (United States)

    Lim, Gee Kwang; Freeman, Robert A.; Tesar, Delbert

    1989-01-01

    The kinematics and dynamics of a Stewart Platform type parallel structure robot (NASA's Dynamic Docking Test System) were modeled using the method of kinematic influence coefficients (KIC) and isomorphic transformations of system dependence from one set of generalized coordinates to another. By specifying the end-effector (platform) time trajectory, the required generalized input forces which would theoretically yield the desired motion were determined. It was found that the relationship between the platform motion and the actuators motion was nonlinear. In addition, the contribution to the total generalized forces, required at the actuators, from the acceleration related terms were found to be more significant than the velocity related terms. Hence, the curve representing the total required actuator force generally resembled the curve for the acceleration related force. Another observation revealed that the acceleration related effective inertia matrix I sub dd had the tendency to decouple, with the elements on the main diagonal of I sub dd being larger than the off-diagonal elements, while the velocity related inertia power array P sub ddd did not show such tendency. This tendency results in the acceleration related force curve of a given actuator resembling the acceleration profile of that particular actuator. Furthermore, it was indicated that the effective inertia matrix for the legs is more decoupled than that for the platform. These observations provide essential information for further research to develop an effective control strategy for real-time control of the Dynamic Docking Test System.

  5. Benthic assemblages on artificial reefs in the northwestern Adriatic Sea: does structure type and age matter?

    Science.gov (United States)

    Ponti, Massimo; Fava, Federica; Perlini, Rossella Angela; Giovanardi, Otello; Abbiati, Marco

    2015-03-01

    The use of artificial reefs is on the rise worldwide. While their fish aggregating effects are well known, the epibenthic assemblages have been poorly investigated. Two types of artificial reefs (pyramids of concrete slabs and bundles of concrete tubes) have been deployed out of the Po River Delta in 2006 and 2010. The epibenthic assemblages were investigated in 2009 and 2012. Benthic assemblages on both structure typologies were dominated by species tolerating high sedimentation rates. Dissimilarities were found among assemblages with different ages, and, in less extend, between reef typologies. Colonisation by Mytilus galloprovincialis and other major space occupiers did not follow a clear succession pattern and was not affected by reef typology. Species colonisation was likely driven by variability in environmental conditions and recruitment processes rather than by reef typology. This study suggests that environmental features of the deployment sites should be carefully considered in planning and designing artificial reefs, especially in eutrophic and turbid coastal waters, exposed to high river loads. PMID:25569857

  6. Structure and hard magnetic properties in Nd2Fe14B-type compounds

    International Nuclear Information System (INIS)

    As an example of application of neutron diffraction, magnetic properties of high-performance permanent magnets were reviewed, laying emphasis on rare-earth containing magnets. After introducing a development history of permanent magnets in the last century, basic properties and origin of magnetic anisotropy in ferromagnets were explained in terms of crystalline-electric-field interaction acting on a rare-earth ion. Main part of this article was devoted to a description of the strongest Nd-Fe-B magnet, main phase of which has been assigned to be Nd2Fe14B intermetallic compound by powder neutron diffraction experiments. Structural and magnetic properties in a series of Nd2Fe14B-type compounds were described systematically, including inelastic neutron scattering, small-angle neutron scattering, and high-field magnetization experiments on single crystal samples. Recent issue of Dy-containing Nd-Fe-B magnets for applications in a driving motor of the hybrid electric vehicle was mentioned in the final chapter, which consequently motivated and stimulated a research to enhance the coercivity of the Nd-Fe-B magnets with less Dy content. (author)

  7. Structural basis for the active site inhibition mechanism of human kidney-type glutaminase (KGA).

    Science.gov (United States)

    Thangavelu, K; Chong, Qing Yun; Low, Boon Chuan; Sivaraman, J

    2014-01-01

    Glutaminase is a metabolic enzyme responsible for glutaminolysis, a process harnessed by cancer cells to feed their accelerated growth and proliferation. Among the glutaminase isoforms, human kidney-type glutaminase (KGA) is often upregulated in cancer and is thus touted as an attractive drug target. Here we report the active site inhibition mechanism of KGA through the crystal structure of the catalytic domain of KGA (cKGA) in complex with 6-diazo-5-oxo-L-norleucine (DON), a substrate analogue of glutamine. DON covalently binds with the active site Ser286 and interacts with residues such as Tyr249, Asn335, Glu381, Asn388, Tyr414, Tyr466 and Val484. The nucleophilic attack of Ser286 sidechain on DON releases the diazo group (N2) from the inhibitor and results in the formation of an enzyme-inhibitor complex. Mutational studies confirmed the key role of these residues in the activity of KGA. This study will be important in the development of KGA active site inhibitors for therapeutic interventions. PMID:24451979

  8. Glycosylation of b-Type Flagellin of Pseudomonas aeruginosa: Structural and Genetic Basis

    OpenAIRE

    Verma, Amrisha; Schirm, Michael; Arora, Shiwani K.; Thibault, P.; Logan, Susan M.; Ramphal, Reuben

    2006-01-01

    The flagellin of Pseudomonas aeruginosa can be classified into two major types—a-type or b-type—which can be distinguished on the basis of molecular weight and reactivity with type-specific antisera. Flagellin from the a-type strain PAK was shown to be glycosylated with a heterogeneous O-linked glycan attached to Thr189 and Ser260. Here we show that b-type flagellin from strain PAO1 is also posttranslationally modified with an excess mass of up to 700 Da, which cannot be explained through...

  9. Carbohydrate amino acids: the intrinsic conformational preference for a beta-turn-type structure in a carbopeptoid building block.

    OpenAIRE

    Jockusch, Ra; Talbot, Fo; Rogers, Ps; Simone, Mi; Fleet, Gw; Simons, Jp

    2006-01-01

    Infrared ion-dip spectroscopy coupled with DFT and ab initio calculations are used to establish the intrinsic conformational preference of the basic structural unit of a peptide mimic, a cis-tetrahydrofuran-based "carbopeptoid" (amide-sugar-amide), isolated at low temperature in the gas phase. The carbopeptoid units form a beta-turn-type structure, stabilized by an intramolecular NH --> O=C hydrogen bond across the sugar ring, thus forming a 10-membered, C10 turn. Despite the clear preference...

  10. Complete {sup 1}H and {sup 13}C NMR structural assignments for a group of four goyazensolide-type furanoheliangolides

    Energy Technology Data Exchange (ETDEWEB)

    Soares, Ana Carolina Ferreira; Silva, Aline Nazare; Matos, Priscilla Mendonca; Silva, Eder Henrique da; Heleno, Vladimir Constantino Gomes [Universidade de Franca, Franca, SP (Brazil). Nucleo de Pesquisas em Ciencias Exatas e Tecnologicas; Lopes, Norberto Peporine; Lopes, Joao Luis Callegari [Universidade de Sao Paulo (FCFRP/USP), Ribeirao Preto, SP (Brazil). Fac. de Ciencias Farmaceuticas de Ribeirao Preto. Dept. de Quimica e Fisica; Sass, Daiane Cristina, E-mail: vheleno_05@yahoo.com.br [Universidade de Sao Paulo (FFCLRP/USP), Ribeirao Preto, SP (Brazil). Fac. de Filosofia, Ciencias e Letras de Ribeirao Preto. Dept. de Quimica

    2012-07-01

    Four goyazensolide-type sesquiterpene lactones - lychnofolide, centratherin, goyazensolide and goyazensolide acetate - were thoroughly studied by NMR experimental techniques. {sup 1}H NMR, {sup 13}C NMR {l_brace}{sup 1}H{r_brace}, COSY, HMQC, HMBC, J-res. and NOE experiments were performed to provide the needed structural information. Complete and unequivocal assignment, including the determination of all multiplicities, was obtained for each structure and the data collections are presented in tables (author)

  11. Potential Use of Avocado Oil on Structured Lipids MLM-Type Production Catalysed by Commercial Immobilised Lipases

    OpenAIRE

    Caballero, Eduardo; Soto, Carmen; Olivares, Araceli; Altamirano, Claudia

    2014-01-01

    Structured Lipids are generally constituents of functional foods. Growing demands for SL are based on a fuller understanding of nutritional requirements, lipid metabolism, and improved methods to produce them. Specifically, this work was aimed to add value to avocado oil by producing dietary triacylglycerols (TAG) containing medium-chain fatty acids (M) at positions sn-1,3 and long-chain fatty acids (L) at position sn-2. These MLM-type structured lipids (SL) were produced by interesterificati...

  12. Sensitive Elements of Magnetic Field Sensors Formation as Spin-Valve Type Multilayer Structures Based on Co and Cu

    Directory of Open Access Journals (Sweden)

    Kostenko M.V.

    2014-08-01

    Full Text Available In this paper proposed a method of forming the sensitive elements of sensors magnetic field as a spin-valve type multilayer structures based on Co and Cu. Presents the results of the study their magnetoresistive properties. It is shown that the spin-valve structure such as Co/Cu/Cu works most efficiently with a thickness of intermediate layer Cu 8 nm and the thickness of the magnetic layers 6 nm (top and 20 nm (bottom.

  13. Riemann type algebraic structures and their differential-algebraic integrability analysis

    Directory of Open Access Journals (Sweden)

    Prykarpatsky A.K.

    2010-06-01

    Full Text Available The differential-algebraic approach to studying the Lax type integrability of generalized Riemann type equations is devised. The differentiations and the associated invariant differential ideals are analyzed in detail. The approach is also applied to studying the Lax type integrability of the well known Korteweg-de Vries dynamical system.

  14. A structure for quasars under the scope of polarisation I. The UV/optical polarisation dichotomy of type-1 and type-2 AGN

    CERN Document Server

    Marin, F

    2013-01-01

    We present UV/optical spectropolarimetric modelling of the phenomenologically-based structure for quasars proposed by Elvis (2000). In this first paper of a series, we explore the continuum polarisation emerging from radiatively accelerated and bent winds that were vertically launched from the accretion disc in an active galactic nucleus (AGN). We simulate the radiative transfer occurring in Thomson scattering and dust extinction media over a range of morphological parameters and optical depths of the wind. We demonstrate that the wind geometry proposed by Elvis with a phenomenologically-derived bending angle of theta = 60deg still underestimates the observed optical polarisation percentage of type-1 and type-2 AGN and does not yet reproduce the expected dichotomy of the polarisation position angle. To recover the observed polarisation properties, a smaller bending angle and some amount of dust shielding in the equatorial region should be considered. A two-phase outflow is found to generate both the observed ...

  15. Numerical simulation for dynamic response of interactive system between soil and RC duct-type structures in nuclear power plants

    International Nuclear Information System (INIS)

    Dynamic numerical simulation of a coupled soil-structure system by non-linear finite element method is presented. The target structure is the underground duct-type structure for emergency services in nuclear power plants. By appropriately modeling, including refinements in dynamic soil model and introduction of interface element, etc., the simulated results are in a very good agreement with the experimental results in terms of dynamic amplitudes and damaging process. A simple mesh generation program specific for the system with optimization concern is made. Some issues on computational aspects are then addressed. (author)

  16. Experimental and theoretical evidence for pressure-induced metallization in FeO with the rock-salt type structure

    CERN Document Server

    Ohta, Kenji; Hirose, Kei; Haule, Kristjan; Shimizu, Katsuya; Ohishi, Yasuo

    2011-01-01

    Electrical conductivity of FeO was measured up to 141 GPa and 2480 K in a laserheated diamond-anvil cell. The results show that rock-salt (B1) type structured FeO metallizes at around 70 GPa and 1900 K without any structural phase transition. We computed fully self-consistently the electronic structure and the electrical conductivity of B1 FeO as a function of pressure and temperature, and found that although insulating as expected at ambient condition, B1 FeO metallizes at high temperatures, consistent with experiments. The observed metallization is related to spin crossover.

  17. Magnetic field structure in single late-type giants: the effectively single giant V390 Aurigae

    Science.gov (United States)

    Konstantinova-Antova, R.; Aurière, M.; Petit, P.; Charbonnel, C.; Tsvetkova, S.; Lèbre, A.; Bogdanovski, R.

    2012-05-01

    Aims: We have studied the active giant V390 Aur using spectropolarimetry to obtain direct and simultaneous measurements of the magnetic field and the activity indicators to obtain a precise insight of its activity. Methods: We used the spectropolarimeter NARVAL at the Bernard Lyot Telescope (Observatoire du Pic du Midi, France) to obtain a series of Stokes I and Stokes V profiles. Using the least-squares deconvolution (LSD) technique we were able to detect the Zeeman signature of the magnetic field in each of our 13 observations and to measure its longitudinal component. Using the wide wavelength range of the spectra we were able to monitor the CaII K&H and IR triplet, as well as the H? lines, which are activity indicators. To reconstruct the magnetic field geometry of V390 Aur on the basis of modelling the Stokes V profiles, we applied the Zeeman Doppler imaging (ZDI) inversion method and present a map for the magnetic field. Based on the obtained spectra, we also refined the fundamental parameters of the star and the Li abundance using MARCS model atmospheres. Results: The ZDI revealed a structure in the radial magnetic field consisting of a polar magnetic spot of positive polarity and several negative spots at lower latitude. A high latitude belt is present on the azimuthal field map, indicative of a toroidal field close to the surface. Similar features are observed in some RS CVn and FK Com -type stars. It was found that the photometric period cannot fit the behaviour of the activity indicators formed in the chromosphere. Their behaviour suggests slower rotation compared to the photosphere, but our dataset is too short for us to be able to estimate their exact periods. All these results can be explained in terms of an ? - ? dynamo operation, taking into account the stellar structure and rotation properties of V390 Aur that we studied with up-to-date stellar models computed at solar metallicity with the code STAREVOL. The calculated Rossby number also points to a very efficient dynamo. Based on data obtained using the Bernard Lyot Telescope at Observatoire du Pic du Midi, CNRS and Université Paul Sabatier, France.

  18. Cationic zirconium hydrides supported by an NNNN-type macrocyclic ligand: synthesis, structure, and reactivity.

    Science.gov (United States)

    Kulinna, Heiko; Spaniol, Thomas P; Maron, Laurent; Okuda, Jun

    2012-11-19

    An air- and light-sensitive, but thermally stable tris[(trimethylsilyl)methyl]zirconium complex containing an NNNN-type macrocyclic ligand [Zr(Me3TACD)(CH2SiMe3)3] (1; Me3TACD = Me3[12]aneN4: 1,4,7-trimethyl-1,4,7,10-tetraazacyclododecane) was prepared by reacting [Zr(CH2SiMe3)4] with (Me3TACD)H. Reaction of the zirconium tris(alkyl) 1 with a Lewis or Brønsted acid gave a dialkyl cation with a weakly coordinating anion [Zr(Me3TACD)(CH2SiMe3)2][A] [A = Al{OC(CF3)3}4 (2a), B{3,5-C6H3(CF3)2}4 (2b), B(3,5-C6H3Cl2)4 (2c), and BPh4) (2d)]. Hydrogenolysis of 2a-2c resulted in the formation of the dinuclear tetrahydride dication [{Zr(Me3TACD)(?-H)2}2][A]2 (3a-3c). Compounds 1-3 were characterized by multinuclear NMR spectroscopy, and the solid-state structures of 1, 2c, and 3b were established by single-crystal X-ray diffraction studies. The dinuclear hydride complex 3b exhibits a quadruply bridged {Zr2(?-H)4} core in solution and in the solid state with a relatively short Zr···Zr distance of 2.8752(11) Å. Density functional theory computations at the B3PW91 level reproduced this structure (Zr···Zr distance of 2.900 Å). The cationic hydride complex 3b reacted with excess carbon monoxide in tetrahydrofuran at room temperature to give ethylene in 25% yield based on 3b. Upon analysis of (13)C NMR spectra of the reaction mixture using (13)CO, oxymethylene and enolate complexes were detected as intermediates among other complexes. PMID:23113709

  19. Coder and decoder of fractal signals of comb-type structure

    Directory of Open Access Journals (Sweden)

    Politanskyi R. L.

    2014-08-01

    Full Text Available The article presents a coder and decoder of fractal signals of comb-type structure (FSCS based on microcontrollers (MC. The coder and decoder consist of identical control modules, while their managed modules have different schematic constructions. The control module performs forming or recognition of signals, and also carries out the function of information exchange with a computer. The basic element of the control module is a PIC18F2550 microcontroller from MicroChip. The coder of the system forms fractal signals of a given order according to the information bits coming from the computer. Samples of the calculated values of the amplitudes of elementary rectangular pulses that constitute the structure of fractal pulses are stored in the memory of the microcontroller as a table. Minimum bit capacity of the DAC necessary for the generation of FSCS of fourth order is four bits. The operation algorithm, "wired" into the controller of the program, provides for encoding of the transmitted information by two-bit symbols. Recognition of the start of transmission of each byte in communication channel is performed by the transmission of the timing signal. In a decoder the microcontroller carries out reception and decoding of the received fractal signals which are then transmitted to the computer. The developed algorithm of the program for the microcontroller of the decoder is carried out by determination of order of fractal impulse after the value of sum of amplitudes of elementary impulses, constituents fractal signal. The programs for coder and decoder are written in "C". In the most critical places of the program influencing on the fast-acting of chart “assembler” insertions are done. The blocks of the coder and decoder were connected with a coaxial 10 meters long cable with an impendance of 75 Ohm. The signals generated by the developed coder of FSCS, were studied using a digital oscillograph. On the basis of the obtained spectrums, it is possible to draw a conclusion, that the fractal signals formed by the coder are wideband and can be used in noise-resistant and protected communication systems.

  20. Magnetic susceptibility of the phases of YAlxGa4-x series with the structures derived from BaAl4-type structure

    International Nuclear Information System (INIS)

    The magnetic susceptibility of the alloys in the concentration region corresponding to five YAlxGa4-x compounds was investigated by the Faraday method. The crystal structures of these compounds are related to the BaAl4-type structure. It was shown that diamagnetism of the investigated alloys is determined by the existence of 6-, 8-, 10-, 12- and 14-term circuits of Me atoms (Ga+Al statistical mixture) in the crystal structures of the YAlxGa4-x compounds. The Me atoms are thought to form ?-type interatomic bonds within these circuits. The diamagnetic constituent of the susceptibility calculated on the basis of the above assumption was found to be in a fairly good agreement with the experimental values of the susceptibility of the investigated phases

  1. Magnetic susceptibility of the phases of YAl{sub x}Ga{sub 4-x} series with the structures derived from BaAl{sub 4}-type structure

    Energy Technology Data Exchange (ETDEWEB)

    Speka, M.V.; Zakharenko, M.I.; Babich, M.G.; Belyavina, N.M.; Markiv, V.Ya

    2003-04-07

    The magnetic susceptibility of the alloys in the concentration region corresponding to five YAl{sub x}Ga{sub 4-x} compounds was investigated by the Faraday method. The crystal structures of these compounds are related to the BaAl{sub 4}-type structure. It was shown that diamagnetism of the investigated alloys is determined by the existence of 6-, 8-, 10-, 12- and 14-term circuits of Me atoms (Ga+Al statistical mixture) in the crystal structures of the YAl{sub x}Ga{sub 4-x} compounds. The Me atoms are thought to form {pi}-type interatomic bonds within these circuits. The diamagnetic constituent of the susceptibility calculated on the basis of the above assumption was found to be in a fairly good agreement with the experimental values of the susceptibility of the investigated phases.

  2. Superconductivity of SrSi2 and BaGe2 with the ?-ThSi2-type structure

    International Nuclear Information System (INIS)

    The purpose of this work was to search for possible superconductivity in stoichiometric SrSi2 and BaGe2 with the ?-ThSi2-type structure. The superconducting transition temperatures Tsub(c) were measured inductively using a standard low frequency mutual inductance bridge. The authors also checked the depression of the critical temperatures with increasing magnetic field. (Auth.)

  3. The type I error rate for in vivo Comet assay data when the hierarchical structure is disregarded

    DEFF Research Database (Denmark)

    Hansen, Merete Kjær; Kulahci, Murat

    2014-01-01

    The Comet assay is a sensitive technique for detection of DNA strand breaks. The experimental design of in vivo Comet assay studies are often hierarchically structured, which should be reWected in the statistical analysis. However, the hierarchical structure sometimes seems to be disregarded, and this imposes considerable impact on the type I error rate. This study aims to demonstrate the implications that result from disregarding the hierarchical structure. DiUerent combinations of the factor levels as they appear in a literature study give type I error rates up to 0.51 and for all combinations the type I error rate is greater than the nominal _ at 0.05. Closed-form expressions based on scaled F-distributions using the Welch-Satterthwaite approximation are provided to show how the type I error rate is aUected. With this study we hope to motivate researchers to be more precise regarding the exposition of the statistical methodology and to suitably account for the hierarchical structure of Comet assay data whenever present.

  4. Synthesis, structure and magnetic behaviour of dinuclear uranium(4) complexes with a 'calixsalophen' type macrocycle

    International Nuclear Information System (INIS)

    Treatment of UCl4 with the octadentate tri-compartmental calixsalophen type macrocycle H4L1 [N,N:N,N-bis(2,2-dihydroxy-3,3-di-methylidene-5,5-di-tert-butyl-biphenyl) benzene-1,2-diamine] in THF or pyridine gave the complexes [U2L1Cl4] (1) and [U2L1Cl4(py)2] (2), respectively. The crystal structures of 1.4THF and 2.3py are centrosymmetric, the metal atoms occupying the N2O2 cavities with either a pentagonal bipyramidal environment in 1, two Cl atoms being in apical positions, or a dodecahedral environment in 2. Reaction of U(acac)4 (acac MeCOCHCOMe) with H4L1 in THF did not afford the corresponding acetylacetonate product but gave instead the isomeric complex [U2L1(acac)4] (3), in which one of the two N2O2 cavities is empty, one of the uranium atoms occupying the central O4 site. The dinuclear complex [U2(HL3)(acac)5] (4) was obtained by treating U(acac)4 with H4L1 in pyridine; in this case, the macrocyclic ligand L1 was transformed into its mono(benzimidazole) derivative L3. The eight-coordinate uranium atoms in 3.5THF and 4.2py adopt a distorted square anti-prismatic configuration. The magnetic properties of compounds 1 and 3 were investigated. (authors)ounds 1 and 3 were investigated. (authors)

  5. Microscopic modeling of water and ions structure and dynamics in storage clays of montmorillonite type

    International Nuclear Information System (INIS)

    Clays are porous media of industrial interest. They are known for their retention capacity towards water and ions. When compacted, swelling clays are used in nuclear industry for the storage of radionuclide wastes. Compaction reduces the pores, whose size becomes microscopic under strong external pressures. In this work, the clay micro-porosity is modelled by montmorillonite inter-layer spaces. Microscopic simulations (Monte Carlo and molecular dynamics) allow to study the structure and the dynamics of ions and water in the medium, according to its state of hydration. After a summary on the clay-water system and the techniques used for mechanical statistical simulations, this work reports the results obtained on two few hydrated homo-ionic clays, neutralized with two types of counter-ions: sodium and cesium. The simulated properties are in agreement with experiments, so validating the modeling. The study of mainly sodic montmorillonites with a small quantity of cesium shows that self diffusion coefficients for Ca+, when integrated in more macroscopic models, lead to values in agreement with those obtained by tracer experiments. Thus the simulated values are much closer to experimental ones than the coefficients obtained thanks to models based on double layer theory. In a last chapter, a systematic comparison between microscopic simulations and continuous solvent models, for more hydrated states, attempts to find the limits of the latter models and the neces limits of the latter models and the necessity of microscopic simulations according to the state of hydration and the desirable precision of the obtained information. (author)

  6. A Scenario for the Fine Structures of Solar Type IIIb Radio Bursts Based on Electron Cyclotron Maser Emission

    Science.gov (United States)

    Wang, C. B.

    2015-06-01

    A scenario based on electron cyclotron maser (ECM) emission is proposed for the fine structures of solar radio emission. It is suggested that under certain conditions modulation of the ratio between the plasma frequency and electron gyro frequency by ultra-low-frequency waves, which is a key parameter for excitation of ECM instability, may lead to the intermittent emission of radio waves. As an example, the explanation for the observed fine-structure components in the solar Type IIIb bursts is discussed in detail. Three primary issues of Type IIIb bursts are addressed: (1) the physical mechanism that results in intermittent emission elements that form a chain in the dynamic spectrum of Type IIIb bursts, (2) the cause of split pairs (or double stria) and triple stria, and (3) why only IIIb–III bursts are observed in the events of fundamental harmonic pair emission whereas IIIb–IIIb or III–IIIb bursts are very rarely observed.

  7. Conceptual design study of Pebble Bed Type High Temperature Gas-cooled Reactor with annular core structure

    International Nuclear Information System (INIS)

    This report presents the Conceptual Design Study of Pebble Bed Type High Temperature Gas-cooled Reactor with Annular Core Structure. From this study, it is made clear that the thermal power of the Pebble Bed Type Reactor can be increased to 500MW through introducing the annular core structure without losing the inherent safe characteristics (in the coolant depressurization accident, the fuel temperature does not exceed the temperature where the fuel defect begins.) This thermal power is two times higher than the inherent safe Pebble Bed Type High temperature Gas-cooled Reactor (MHTGR) designed in West Germany. From this result, it is foreseen that the ratio of the plant cost to the reactor power is reduced and the economy of the plant operation is improved. The reactor performances e.g. fuel burnup and fuel temperature are maintained in same level of the MHTGR. (author)

  8. Stability and electronic structure of the complex K$_2$PtCl$_6$ structure-type hydrides

    OpenAIRE

    Halilov, S. V.; D. J. Singh; GUPTA, M.; Gupta, R.

    2004-01-01

    The stability and bonding of the ternary complex K$_2$PtCl$_6$ structure hydrides is discussed using first principles density functional calculations. The cohesion is dominated by ionic contributions, but ligand field effects are important, and are responsible for the 18-electron rule. Similarities to oxides are discussed in terms of the electronic structure. However, phonon calculations for Sr$_2$RuH$_6$ also show differences, particularly in the polarizability of the RuH$_...

  9. Using a conceptual framework during learning attenuates the loss of expert-type knowledge structure

    OpenAIRE

    Wilcox Elizabeth; Mandin Henry; Novak Kerry; McLaughlin Kevin

    2006-01-01

    Abstract Background During evolution from novice to expert, knowledge structure develops into an abridged network organized around pathophysiological concepts. The objectives of this study were to examine the change in knowledge structure in medical students in one year and to investigate the association between the use of a conceptual framework (diagnostic scheme) and long-term knowledge structure. Methods Medical students' knowledge structure of metabolic alkalosis was studied after instruc...

  10. Different Types of Cell-to-Cell Connections Mediated by Nanotubular Structures

    OpenAIRE

    Veranic?, Peter; Lokar, Marus?a; Schu?tz, Gerhard J.; Weghuber, Julian; Wieser, Stefan; Ha?gerstrand, Henry; Kralj-iglic?, Veronika; Iglic?, Ales?

    2008-01-01

    Communication between cells is crucial for proper functioning of multicellular organisms. The recently discovered membranous tubes, named tunneling nanotubes, that directly bridge neighboring cells may offer a very specific and effective way of intercellular communication. Our experiments on RT4 and T24 urothelial cell lines show that nanotubes that bridge neighboring cells can be divided into two types. The nanotubes of type I are shorter and more dynamic than those of type II, and they cont...

  11. Inhibition Kinetics and Emodin Cocrystal Structure of a Type II Polyketide Ketoreductase†,‡

    OpenAIRE

    Korman, Tyler Paz; Tan, Yuhong; Wong, Justin; Luo, Rui; Tsai, Shiou-Chuan

    2008-01-01

    Type II polyketides are a class of natural products that include pharmaceutically important aromatic compounds such as the antibiotic tetracycline and antitumor compound doxorubicin. The type II polyketide synthase (PKS) is a complex consisting of 5–10 standalone domains homologous to fatty acid synthase (FAS). Polyketide ketoreductase (KR) provides regio- and stereochemical diversity during the reduction. How the type II polyketide KR specifically reduces only the C9 carbonyl group is not we...

  12. BaAl4-type structure derivatives in the Ga-rich part of the Y–Cu–Ga system

    International Nuclear Information System (INIS)

    Highlights: ? We study the crystal structure of Ga-rich compounds in the Y–Cu–Ga system at 500 °C. ? Increasing of Ga-content leads to shift of composition to the higher Y concentration. ? We analyze the behavior of atomic vacancies in the Cu/Ga positions. ? Crystal structure of studied compounds is constructed from the BaAl4-like fragments. - Abstract: The crystal structures of seven Ga-rich compounds that exist in the Y–Cu–Ga system were studied by the X-ray single-crystal and powder diffraction methods. The crystal structures of six phases were shown to be constructed from the orthorhombic distorted BaAl4-like fragments by multiplication of its a and b lattice constants. These compounds are: 1-Y1.02Cu1.35Ga2.63 (modified BaAl4-type structure, 1 × 1 multiplication), 2-Y1.04Cu1.12Ga2.84 and 3-Y1.05Cu1.00Ga2.95 (own type structure, 3 × 3), 4-Y1.08Cu0.72Ga3.20 (own, 9 × 9), 5-Y3Cu4Ga7 and 6-Y3.21Cu3.09Ga7.70 (La3Al11, 3 × 1), 7-YCuGa2 (own, 3 × 3).

  13. Damage evaluation of type 304 and 316LN stainless steel structure under creep-fatigue loading

    International Nuclear Information System (INIS)

    In this study high temperature structural test was carried out in sodium coolant environments and microstructural observation as well as material strength tests were performed to evaluate the damage under structural test. The creep-fatigue load with one period of 3 hours was applied 1055 times over the temperature range of 250 deg C to 600 deg C for the structural test. An investigation of the damage distribution by microscopic images showed that the 316LN specimen was less damaged than the 304SS during the structural test. The results of material strength test with material specimens sampled along the thickness direction in structural model showed that the fatigue strength of 304 and 316LN stainless steels were almost the same with those of the mean fatigue strength curve for the undamaged materials. This means that the structural test model was nearly undamaged during the structural test, and the results are in agreement with those of microscopic observations

  14. Differential progression of structural and functional alterations in distinct retinal ganglion cell types in a mouse model of glaucoma.

    Science.gov (United States)

    Della Santina, Luca; Inman, Denise M; Lupien, Caroline B; Horner, Philip J; Wong, Rachel O L

    2013-10-30

    Intraocular pressure (IOP) elevation is a principal risk factor for glaucoma. Using a microbead injection technique to chronically raise IOP for 15 or 30 d in mice, we identified the early changes in visual response properties of different types of retinal ganglion cells (RGCs) and correlated these changes with neuronal morphology before cell death. Microbead-injected eyes showed reduced optokinetic tracking as well as cell death. In such eyes, multielectrode array recordings revealed that four RGC types show diverse alterations in their light responses upon IOP elevation. OFF-transient RGCs exhibited a more rapid decline in both structural and functional organizations compared with other RGCs. In contrast, although the light-evoked responses of OFF-sustained RGCs were perturbed, the dendritic arbor of this cell type remained intact. ON-transient and ON-sustained RGCs had normal functional receptive field sizes but their spontaneous and light-evoked firing rates were reduced. ON- and OFF-sustained RGCs lost excitatory synapses across an otherwise structurally normal dendritic arbor. Together, our observations indicate that there are changes in spontaneous activity and light-evoked responses in RGCs before detectable dendritic loss. However, when dendrites retract, we found corresponding changes in receptive field center size. Importantly, the effects of IOP elevation are not uniformly manifested in the structure and function of diverse RGC populations, nor are distinct RGC types perturbed within the same time-frame by such a challenge. PMID:24174678

  15. On the geometric structure of characteristic vector fields related with nonlinear equations of the Hamilton-Jacobi type

    Directory of Open Access Journals (Sweden)

    Natalia K. Prykarpatska

    2007-01-01

    Full Text Available The Cartan-Monge geometric approach to the characteristics method for Hamilton-Jacobi type equations and nonlinear partial differential equations of higher orders is analyzed. The Hamiltonian structure of characteristic vector fields related with nonlinear partial differential equations of first order is analyzed, the tensor fields of special structure are constructed for defining characteristic vector fields naturally related with nonlinear partial differential equations of higher orders. The generalized characteristics method is developed in the framework of the symplectic theory within geometric Monge and Cartan pictures. The related characteristic vector fields are constructed making use of specially introduced tensor fields, carrying the symplectic structure. Based on their inherited geometric properties, the related functional-analytic Hopf-Lax type solutions to a wide class of boundary and Cauchy problems for nonlinear partial differential equations of Hamilton-Jacobi type are studied. For the non-canonical Hamilton-Jacobi equations there is stated a relationship between their solutions and a good specified functional-analytic fixed point problem, related with Hopf-Lax type solutions to specially constructed dual canonical Hamilton-Jacobi equations.

  16. The solution structure of the MANEC-type domain from Hepatocyte Growth Factor Activator Inhibitor 1 reveals an unexpected PAN/apple domain-type fold

    DEFF Research Database (Denmark)

    Hong, Zebin; Nowakowski, Michal

    2015-01-01

    A decade ago, a Motif at N-terminus with Eight-Cysteines or in short MANEC was defined as a new protein domain family. This domain is found exclusively in the N-terminus of >400 multi-domain type-1 transmembrane proteins from animals. Despite the large number of MANEC-containing proteins, only one has been characterized at the protein level: hepatocyte growth factor activator inhibitor-1 (HAI-1). HAI-1 is an essential protein, as knockout mice die in utero due to placental defects. HAI-1 is an inhibitor of matriptase, hepsin and hepatocyte growth factor activator, all serine proteases with important roles in epithelial development, cell growth and homeostasis. Dysregulation of these proteases has been causatively implicated in pathological conditions such as skin diseases and cancer. Detailed functional understanding of HAI-1 and other MANEC-containing proteins is hampered by the lack of structural information on MANEC. Although many MANEC sequences exist, sequence-based database searches fail to predict structural homology. Here we present the NMR solution structure of the MANEC domain from HAI-1, the first three-dimensional structure from the MANEC domain family. Unexpectedly, MANEC is a new subclass of the PAN/apple domain family, with its own unifying features, such as two additional disulfide bonds, two extended loop regions and additional ?-helical elements. As shown for other PAN/apple domain-containing proteins, we propose a similar active role of the MANEC domain in intramolecular and intermolecular interactions. The structure provides a tool for the further elucidation of HAI-1 function as well as a reference for the study of other MANEC-containing proteins.

  17. Structural Stability of Riemann Solutions for a Multiphase Kinematic Conservation Law Model that Changes Type.

    Science.gov (United States)

    Vinod, Vaidyanath

    We consider a model for 2-way traffic flow introduced by Bick and Newell in 1960 (2). The model problem is: p_{t} + (pu)_{x } = 0; quad q_{t} + (qv)_ {x} = 0.eqno(0.1)Here p and q are the densities of cars in the two directions of flow and u and v are the respective velocities in the p and q directions; a choice suggested in (2) is u = 1 - p - beta q, v = -1 + q + beta p.. In this model, beta is a measure of the interaction between the two directions of flow. For the problem to be physically feasible, we require 0=0, q=0, and -1 + q + beta p>=0.. When beta = 0, there is no interaction between the two directions of flow and then the system (0.1) reduces to a system of scalar equation for which the Riemann problem (Cauchy problem) to (0.1) with initial data of the form: U(x,0) = cases{{U_0,quad x 0} cr}has a unique solution in the class of Lax entropy or admissible wave solutions. In this case, there is an open set of initial states (U_0, U_1) for which the solution exhibits the phenomenon of 'overlapping rarefaction waves'. These waves occupy the same position in the physical plane and they are stable. When beta>0, for the same initial values U_0 and U_1, these overlapping rarefaction solutions disappear due to the presence of an elliptic region. For these states, we introduce a new shock solution which we term a critical shock (this is qualitatively similar to a Buckley-Leverett shock). The strength of the shock goes to zero as beta tends to zero; and this solution approaches the overlapping wave solution. The main result of this thesis is that these constructed solutions are structurally stable as beta approaches zero (that is, the elliptic region shrinks to a line); and that they converge strongly in L^1. The construction might prove useful in solving other problems that change type, for example models for three-phase flow in porous media (1) or compressible two-phase flow (19). In this dissertation, we present the stability result for one new case, which typifies the difficulties involved.

  18. Structural and biochemical studies of the hedamycin type II polyketide ketoreductase (HedKR): molecular basis of stereo- and regiospecificities.

    Science.gov (United States)

    Javidpour, Pouya; Das, Abhirup; Khosla, Chaitan; Tsai, Shiou-Chuan

    2011-08-30

    Bacterial aromatic polyketides that include many antibiotic and antitumor therapeutics are biosynthesized by the type II polyketide synthase (PKS), which consists of 5-10 stand-alone enzymatic domains. Hedamycin, an antitumor antibiotic polyketide, is uniquely primed with a hexadienyl group generated by a type I PKS followed by coupling to a downstream type II PKS to biosynthesize a 24-carbon polyketide, whose C9 position is reduced by hedamycin type II ketoreductase (hedKR). HedKR is homologous to the actinorhodin KR (actKR), for which we have conducted extensive structural studies previously. How hedKR can accommodate a longer polyketide substrate than the actKR, and the molecular basis of its regio- and stereospecificities, is not well understood. Here we present a detailed study of hedKR that sheds light on its specificity. Sequence alignment of KRs predicts that hedKR is less active than actKR, with significant differences in substrate/inhibitor recognition. In vitro and in vivo assays of hedKR confirmed this hypothesis. The hedKR crystal structure further provides the molecular basis for the observed differences between hedKR and actKR in the recognition of substrates and inhibitors. Instead of the 94-PGG-96 motif observed in actKR, hedKR has the 92-NGG-94 motif, leading to S-dominant stereospecificity, whose molecular basis can be explained by the crystal structure. Together with mutations, assay results, docking simulations, and the hedKR crystal structure, a model for the observed regio- and stereospecificities is presented herein that elucidates how different type II KRs recognize substrates with different chain lengths, yet precisely reduce only the C9-carbonyl group. The molecular features of hedKR important for regio- and stereospecificities can potentially be applied to biosynthesize new polyketides via protein engineering that rationally controls polyketide ketoreduction. PMID:21776967

  19. Stability and electronic structure of the complex K$_2$PtCl$_6$ structure-type hydrides

    CERN Document Server

    Halilov, S V; Sen-Gupta, M; Gupta, R

    2004-01-01

    The stability and bonding of the ternary complex K$_2$PtCl$_6$ structure hydrides is discussed using first principles density functional calculations. The cohesion is dominated by ionic contributions, but ligand field effects are important, and are responsible for the 18-electron rule. Similarities to oxides are discussed in terms of the electronic structure. However, phonon calculations for Sr$_2$RuH$_6$ also show differences, particularly in the polarizability of the RuH$_6$ octahedra. Nevertheless, the yet to be made compounds Pb$_2$RuH$_6$ and Be$_2$FeH$_6$ are possible ferroelectrics. The electronic structure and magnetic properties of the decomposition product, FeBe$_2$ are reported. Implications of the results for H storage are discussed.

  20. Rietveld Structure Refinement and Raman Spectroscopy of Pyrochlore-type Oxygen-rich Ce2Zr2O8 Phase

    Directory of Open Access Journals (Sweden)

    XIE Hua, WANG Lie-Lin, LUO De-Li

    2014-05-01

    Full Text Available Pyrochlore-type oxygen-rich Ce2Zr2O8 phase was prepared successfully by graphite reduction method. In order to compare the structure between Ce2Zr2O8 and Nd2Zr2O7, the pyrochlore Nd2Zr2O7 was selected as the substitute of CeZrO3.5+?, the oxide precursor of Ce2Zr2O8. Experimental results show that excessive oxygen in the Ce2Zr2O8 structure mainly occupies the oxygen vacancies from the precursor structure. Oxygen ions diffusion in the precursor CeZrO3.5 structure does not destroy the ordering cation sublattice. Meanwhile, Zr-O ligands are transformed from octahedrons of co-top connection in the precursor to cubes of co-edge connection in the Ce2Zr2O8. The antiphase boundary density and Raman bands in comparison with?the precursor are improved significantly, suggesting the structure of Ce2Zr2O8 phase is in a metastable state. The characteristic structure facililates rapid adsorption or release of oxygen ions, providing structural feasibility for ideal candidate materials for automobile exhaust purification. However, the structure of Ce2Zr2O8 indicated that the radiation resistance and chemical stability may be downward when An2Zr2O7 pyrochlore under self irradiation condition transforms to the oxygen-rich phase An2Zr2O8.

  1. High resolution structures of the bone morphogenetic protein type II receptor in two crystal forms: Implications for ligand binding

    International Nuclear Information System (INIS)

    BMPRII is a type II TGF-? serine threonine kinase receptor which is integral to the bone morphogenetic protein (BMP) signalling pathway. It is known to bind BMP and growth differentiation factor (GDF) ligands, and has overlapping ligand specificity with the activin type II receptor, ActRII. In contrast to activin and TGF-? type ligands, BMPs bind to type II receptors with lower affinity than type I receptors. Crystals of the BMPRII ectodomain were grown in two different forms, both of which diffracted to high resolution. The tetragonal form exhibited some disorder, whereas the entire polypeptide was seen in the orthorhombic form. The two structures retain the basic three-finger toxin fold of other TGF-? receptor ectodomains, and share the main hydrophobic patch used by ActRII to bind various ligands. However, they present different conformations of the A-loop at the periphery of the proposed ligand-binding interface, in conjunction with rearrangement of a disulfide bridge within the loop. This particular disulfide (Cys94-Cys117) is only present in BMPRII and activin receptors, suggesting that it is important for their likely shared mode of binding. Evidence is presented that the two crystal forms represent ligand-bound and free conformations of BMPRII. Comparison with the solved structure of ActRII bound to BMP2 suggests that His87, unique amongst TGF-? receptors, may play a key role in ligand recognition

  2. Crystal structure and magnesium location in the W-type hexagonal Ferrite: [Ba]Mg 2-W

    Science.gov (United States)

    Collomb, A.; Abdelkader, O.; Wolfers, P.; Guitel, J. C.; Samaras, D.

    1986-04-01

    The crystal structure of BaMg 2Fe 16O 27 W-type hexagonal ferrite has been refined from X-ray single crystal data. This compound is hexagonal: a = 5.9060(7) Å and c = 32.915(7) Å, space group P6 3/mmc, with two formula units per cell. The structure can be described by the sequence ⋯ R overlineSSR? overlineS?S? ⋯, where R and S are the structural blocks already met in the hexaferrite M-structure. Moreover, the location of the Mg 2+ cation among the seven sublattices is given: this cation lies essentially in the octahedral and tetrahedral sites of the spinel S-blocks.

  3. Improvement of display-type spherical mirror analyzer for real space mapping of electronic and atomic structures

    International Nuclear Information System (INIS)

    We have improved a display-type spherical mirror analyzer (DIANA) at Ritsumeikan University SR Center BL-7 for in situ real space mapping of electronic and atomic structures that uses a focused electron beam and a linearly polarized synchrotron radiation (SR). The outer sphere was fully optimized. Compared to the previous analyzer, the energy resolution (?E/E) has been improved from 1% to 0.09±0.02%. A newly designed electron gun for measurement of atomic structures was installed inside the analyzer. Thus the measurement of electronic and atomic structures at the same sample position became possible. Here we report on the improvements of the new DIANA and the results of the first in situ measurement of real space mapping of the valence band and scanning Auger electron microscopy (SAM) of a multiple domain Kish graphite. The crystal orientations of each domain were determined from the electronic structures

  4. On the Conjugacy of Two Types of Wavelike Structures in the Low-Latitude Bottomside F layer

    Science.gov (United States)

    Tsunoda, R. T.

    2014-12-01

    Wavelike structures are often observed in the bottomside of the low-latitude F layer. Whether they are mirrored in the opposite hemisphere, following along geomagnetic field (B) lines, or not, remains an open question. We consider the issue of conjugacy in terms of electrical coupling, and two types of wavelike structures, those produced by plasma transport along B lines (via ion drag), and those produced by plasma transport transverse to B lines (via a polarization electric field). The presence or absence of conjugate plasma structures was investigated by analyzing total electron content (TEC) variations measured with a ground cluster of radio beacon receivers. Polar-orbiting beacon satellites (Cosmos series) and an equatorial-orbiting (Communication/Navigation Outage Forecasting System, or C/NOFS) beacon satellite were used. We present examples of conjugate and non-conjugate plasma structures, which are consistent with the notion that a polarization electric field develops, which then maps along B lines to the conjugate hemisphere.

  5. Redetermination of Nd2Ti2O7: a non-centrosymmetric structure with perovskite-type slabs

    OpenAIRE

    Nobuo Ishizawa; Keisuke Ninomiya; Terutoshi Sakakura; Jun Wang

    2013-01-01

    Single crystals of dineodymium(III) dititanium(IV) heptaoxide, Nd2Ti2O7, were synthesized by the flux method and found to belong to the family of compounds with perovskite-type structural motifs. The asymmetric unit contains four Nd, four Ti and 14 O-atom sites. The perovskite-type slabs are stacked parallel to (010) with a thickness corresponding to four corner-sharing TiO6 octahedra. The Nd and Ti ions are displaced from the geometrical centres of respective coordination polyhedra so that t...

  6. New phases of A2B2O7 type with layered perovskite-like structure

    International Nuclear Information System (INIS)

    Synthesis of a number of phases (CaLaTiTaO7, CaPrTiNbO7, Eu2Ti2O7) with layered perovskite-like structure by treatment of their modification with pyrochlore structures at 70x108-80x108 Pa and 1400-1900 deg C is shown to be possible. Study of thermal stability of Sm2Ti2O7 high pressure phase with layered perovskite-like structure is carried out

  7. Structure refinement of Mg2Cu and a comparison of the Mg2Cu, Mg2Ni and Al2Cu structure types

    International Nuclear Information System (INIS)

    Dimagnesium copper, Mg2Cu, Mr=112.170, orthorhombic, Fddd (70), a=5.275(1), b=9.044(1), c=18.328(2) A, V=874.3(2) A3, Z=16, Dx=3.41 g cm-3, Mo K? (?=0.71073 A), ?=101.145 cm-1, F(000)=848, T=293 K, R=0.034 (wR=0.031) for 17 refined parameters and 310 observed X-ray single-crystal reflections [F0>3?(F0)]. The refined parameters are consistent with the nonrefined parameters reported by Schubert and Anderko. The Mg2Cu structure type can be derived by a stacking of slabs that build up the Al2Cu and Mg2Ni structure types. (orig.)

  8. La{sub 3}Ir{sub 2} with rhombohedral Er{sub 3}Ni{sub 2}-type structure

    Energy Technology Data Exchange (ETDEWEB)

    Schaefer, Konrad; Poettgen, Rainer [Muenster Univ. (Germany). Inst. fuer Anorganische und Analytische Chemie

    2014-10-15

    La{sub 3}Ir{sub 2} is formed upon reaction of the elements at 1273 K in a sealed silica ampoule. The structure was refined from single-crystal X-ray diffractometer data: Er{sub 3}Ni{sub 2}-type structure, R anti 3, a = 895.26(2), c = 1713.01(5) pm, wR = 0.0578, 766 F{sup 2} values, 25 variables. The structure is composed of two simple basic building units: slightly distorted La1 rate at La3{sub 6}La2{sub 2} cubes resembling the tungsten structure and Ir{sub 2} rate at La1{sub 1}La2{sub 2}La3{sub 5} units with an AlB{sub 2}-related coordination (298 pm Ir-Ir in the dumb-bell). Each cube is coordinated by six of the AlB{sub 2} units. The relationship with the U{sub 3}Si{sub 2}-type structure is discussed.

  9. Prediction of protein secondary structure based on residue pair types and conformational states using dynamic programming algorithm.

    Science.gov (United States)

    Sadeghi, Mehdi; Parto, Sahar; Arab, Shahriar; Ranjbar, Bijan

    2005-06-20

    We have used a statistical approach for protein secondary structure prediction based on information theory and simultaneously taking into consideration pairwise residue types and conformational states. Since the prediction of residue secondary structure by one residue window sliding make ambiguity in state prediction, we used a dynamic programming algorithm to find the path with maximum score. A score system for residue pairs in particular conformations is derived for adjacent neighbors up to ten residue apart in sequence. The three state overall per-residue accuracy, Q3, of this method in a jackknife test with dataset created from PDBSELECT is more than 70%. PMID:15936021

  10. Microscopic investigation on morphologies of bilayer gel structure in the mixed polyoxyethylene-type nonionic surfactant systems.

    Science.gov (United States)

    Nagai, Yuko; Kawabata, Youhei; Kato, Tadashi

    2012-10-18

    We investigated morphologies of lamellar domains below the Krafft temperature in the mixed polyoxyethylene-type nonionic surfactant, a C(16)E(6)/C(16)E(7)/water system, by using optical microscopy, confocal microscopy, small/wide-angle X-ray scattering, and small-angle neutron scattering. We have found that the morphology discontinuously changes from network structures of lamellar domains to spherical vesicles with increasing mole fraction of C(16)E(7), via the coexistence region of vesicles and network structures of lamellar domains. PMID:22994139

  11. An effective Skyrme-type interaction for the calculation of nuclear structures of the whole mass table

    International Nuclear Information System (INIS)

    The Hartree-Fock-Bogolyubov formalism is extended for 3 body interactions and applied to spherical nuclei. The structure of the proposed extension of the Skyrme-type interaction is given, together with the analytical expression of the corresponding Hartree-Fock differential equation. The Skyrme-force parameters are modified in order to be able to reproduce the ground state properties. The problem of the spin-stability of the proposed interaction is treated. The Skyrme-interaction is applied as particle-hole interaction and saturation properties are studied. Structure of the charge, neutron density distributions and changes introduced by adding protons or neutrons are treated. (MDC)

  12. Structure of the pseudorabies virus capsid: comparison with herpes simplex virus type 1 and differential binding of essential minor proteins

    OpenAIRE

    Homa, FL; Huffman, JB; Toropova, K; Lopez, HR; Makhov, AM; Conway, JF

    2013-01-01

    The structure of pseudorabies virus (PRV) capsids isolated from the nucleus of infected cells and from PRV virions was determined by cryo-electron microscopy (cryo-EM), and compared to herpes simplex virus type 1 (HSV-1) capsids. PRV capsid structures closely resemble those of HSV-1, including distribution of the capsid vertex specific component (CVSC) of HSV-1, which is a heterodimer of the pUL17 and pUL25 proteins. Occupancy of CVSC on all PRV capsids is near 100%, compared to ~50% reported...

  13. PbS/PbSe structures with core-shell type morphology synthesized from PbS nanocrystals

    International Nuclear Information System (INIS)

    Colloidal PbS/PbSe nanostructures with core-shell type morphology have been synthesized for the first time using a simple chemical procedure where template PbS nanocrystals (NCs) were treated with Se solution in tributylphosphine at elevated temperature. The Se-coated PbS NCs were structurally and optically characterized by high resolution transmission electron microscopy (HRTEM), x-ray diffraction (XRD), Rutherford backscattering spectrometry (RBS) analysis, absorption and photoluminescence (PL) spectroscopy. Synthesized PbS/PbSe structures can be of particular importance in photovoltaic applications where fabrication of heterostructures with compositional modulation on the nanometer scale is essential

  14. Effective exchange constant and electronic structure of pseudo-gap-type L10-MnPd alloys

    International Nuclear Information System (INIS)

    The electrical resistivity, magnetic and low-temperature specific heat measurements, and theoretical calculations for L10-type MnPd alloy system were carried out in a wide range of composition from 40 to 60% Pd. In the present antiferromagnetic alloy system, the highest Neel temperature TN was observed in the vicinity of 53% Pd concentration, deviating from the equiatomic concentration. This behavior was also conformed by the theoretical calculations for the effective exchange constant J0 which gives the value of TN. In the temperature dependence of electrical resistivity for the L10-type MnPd alloys, a characteristic behavior of a hump just below TN was observed, which is associated with the pseudo-gap-type antiferromagnets. In addition, the value of the electronic specific heat coefficient ?e is significantly small below 1 mJ mol-1K-2 above K-2 above 50% Pd, reflecting the very low density of states at the Fermi energy EF. The linear relation between the magnetic moment and the Pauling valence has been confirmed in the L10-type Mn alloy systems, together with that of other Mn alloy systems. The present several results strongly imply that the characteristic electronic structure with the pseudo-gap and the Pauling valence (PV) associated with the covalent bonding state is closely interrelated in the L10-type Mn alloy systems. he L10-type Mn alloy systems. (author)

  15. On negative flows of the AKNS hierarchy and a class of deformations of a bihamiltonian structure of hydrodynamic type

    International Nuclear Information System (INIS)

    A deformation parameter of a bihamiltonian structure of hydrodynamic type is shown to parametrize different extensions of the AKNS hierarchy to include negative flows. This construction establishes a purely algebraic link between, on the one hand, two realizations of the first negative flow of the AKNS model and, on the other, two-component generalizations of Camassa-Holm- and Dym-type equations. The two-component generalizations of Camassa-Holm- and Dym-type equations can be obtained from the negative-order Hamiltonians constructed from the Lenard relations recursively applied on the Casimir of the first Poisson bracket of hydrodynamic type. The positive-order Hamiltonians, which follow from the Lenard scheme applied on the Casimir of the second Poisson bracket of hydrodynamic type, are shown to coincide with the Hamiltonians of the AKNS model. The AKNS Hamiltonians give rise to charges conserved with respect to equations of motion of two-component Camassa-Holm- and two-component Dym-type equations

  16. Structural Basis of Gate-DNA Breakage and Resealing by Type II Topoisomerases

    OpenAIRE

    Laponogov, Ivan; Pan, Xiao-su; Veselkov, Dennis A.; Mcauley, Katherine E.; Fisher, L. Mark; Sanderson, Mark R.

    2010-01-01

    Type II DNA topoisomerases are ubiquitous enzymes with essential functions in DNA replication, recombination and transcription. They change DNA topology by forming a transient covalent cleavage complex with a gate-DNA duplex that allows transport of a second duplex though the gate. Despite its biological importance and targeting by anticancer and antibacterial drugs, cleavage complex formation and reversal is not understood for any type II enzyme. To address the mechanism, we have used X-ray ...

  17. Human fetal pancreatic islet-like structures as source material to treat type 1 diabetes

    OpenAIRE

    Ikeda, Yasuhiro; Kudva, Yogish C.

    2013-01-01

    The incidence of type 1 diabetes is increasing worldwide. Current therapy continues to be suboptimal. An exciting therapeutic advance in the short term is closed loop technology development and application. However, cell and tissue therapy continues to be an unmet need for the disorder. Human islets isolated from deceased donors will be clinically available to treat type 1 diabetes within the next 1 to 2 years. Other approaches such as xenotransplantation and islet products derived from human...

  18. Pressure-induced incompressibility and point singularity of mechanical properties of TaC in NiAs-type structure

    International Nuclear Information System (INIS)

    The structural and elastic properties of TaC in NiAs-type structure under high pressure have been investigated using first principles calculations based on density functional theory. Results indicate that the incompressibility along the c-axis of TaC exceeds that of diamond under higher pressure. Particularly, an interesting point singularity exists in its mechanical properties as the pressure increases from 20 GPa to 40 GPa. The minimal shear modulus, Young's modulus, Debye temperature, and maximum Poisson ratio of TaC are simultaneously obtained at 28 GPa. The calculations of hardness indicate that the NiAs-type TaC crystal possesses excellent mechanical properties. (copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  19. The characteristics of high-temperature biaxial fatigue strength in type 304 stainless steel for FBR high-temperature structures

    International Nuclear Information System (INIS)

    As a link the chain of ''Study for practical use of Tank Type FBR'', ''Practical use of inelastic analysis method to FBR structural design'' is carried out as a cooperative study for three years from 1984. In a cooperative study, investigation such as high-temperature deformation behavior and high-temperature fatigue life characteristics of structure materials is one of the most important problems. So we conduct tension compresion-tortion tests with Type 304 stainless steel to evaluate biaxial fatigue life characteristics at high temperature. As the first step to investigate fatigue life characteristics of reactor vessel material subjected to cyclic thermalstress, we test under time independent fatigue condition. This report shows evaluation results of these tests. We find that biaxial fatigue lives have good relation to Brown's equivalent shear strain parameter which is biaxial fatigue evaluation parameter included crack propagation characteristics. (author)

  20. An Examination of the Influence of Organizational Structure Types and Management Levels on Knowledge Management Practices in Organizations

    OpenAIRE

    Jen S. Steiger; Khalid Ait Hammou; Md Hasan Galib

    2014-01-01

    The purpose of this study was to investigate the difference between organizational structure types, andmanagement levels, in terms of perceived levels of knowledge management practices within organizations. Datawere collected from a sample of 155 individuals employed in San Diego County by way of a web-based survey,and were analyzed using analysis of variance (ANOVA). The results of the study indicate that the knowledgemanagement practices of knowledge transfer, information filtering, and kno...

  1. LES of turbulent convection in solar-type stars and formation of large-scale magnetic structures

    OpenAIRE

    Rogachevskii, I.; Kleeorin, N.; Kitiashvili, I. N.; Kosovichev, A. G.; Wray, A. A.; Mansour, N. N.

    2011-01-01

    In this study we investigate the effects of turbulent convection on formation of large-scale inhomogeneous magnetic structures by means of Large-Eddy Simulation (LES) for convection in solar-type stars. The main idea of this study is the implementation of a new subgrid-scale model for the effective Lorentz force in a three-dimensional nonlinear radiative magnetohydrodynamics (MHD) code developed for simulating the upper solar convection zone and lower atmosphere. To this end...

  2. Crystal chemistry of cerium in the monazite structure-type phase of tailored-ceramic nuclear waste forms

    International Nuclear Information System (INIS)

    Monazite prepared at 1200/degree/C in air was observed to incorporate cerium as 3+ and not 4+ even when charge compensation mechanisms for Ce/sup 4+/ inclusion were present. The consequences of this phenomenon for the use of monazite structure-type solid solutions for transuranic nuclide isolation in radioactive waste management are discussed. The use of cerium as a substitute for the actinides is also considered. 38 refs

  3. Types of tectonic structures, sedimentary volcanogenetic formations of a mantle, favourable processes for exogenetic and polygenetic uranium deposits formation

    International Nuclear Information System (INIS)

    Factors, affecting mineralization processes are considered. Characteristic features of uranium-bearing provinces are as follows: the presence of crust of continental type; deep-seated tectonic structures-rises and saggings, roofs, gneiss domes, rift zones and transform fractures; specialization for uranium of sedimentary and magmatic formations; the presence of manifestation regions of deep thermal and gaseous flow, etc. In uranium-bearing provinces territories favourable for the manifestation of different types of uranium mineralization: metamorphogenetic, polygenetic and exogenetic ones, are singled out. Different epochs of uranium ore formation are established. In sedimentary masses tectonic regime and climate are of special importance, and for epigenetic deposits, formed with an aid of underground waters-hydrogeological conditions. In the limits of the main structural elements of the Earth crust and geotectonic structures of higher orders the following types of sedimentary and volcanic formations can be singled out: 1-formations with exogenous uranium mineralization; 2-formations, accumulated in the epochs of epigenous ore formation; 3-formations fav ourable for epigenous uranium deposit formation; 4-formations unfavourable for the formation and localization of uranium mineralization

  4. Structural analysis of plate-type fuel assemblies and development of a non-destructive method to assess their integrity

    International Nuclear Information System (INIS)

    Highlights: • A plate-type fuel assembly is made of thin plates mounted in a box-like structure. • Drag force from the coolant can shift the plates. • A non invasive method is proposed to test the strength of the plate connections. • The natural frequencies’ shift is used to assess the fuel integrity. -- Abstract: This work is concerned with the structural behaviour and the integrity of parallel plate-type nuclear fuel assemblies. A plate-type assembly consists of several thin plates mounted in a box-like structure and is subjected to a coolant flow that can result in a considerable drag force. A finite element model of an assembly is presented to study the sensitivity of the natural frequencies to the stiffness of the plates’ junctions. It is shown that the shift in the natural frequencies of the torsional modes can be used to check the global integrity of the fuel assembly while the local natural frequencies of the inner plates can be used to estimate the maximum drag force they can resist. Finally a non-destructive method is developed to assess the resistance of the inner plates to bear an applied load. Extensive computational and experimental results are presented to prove the applicability of the method presented

  5. Structural analysis of plate-type fuel assemblies and development of a non-destructive method to assess their integrity

    Energy Technology Data Exchange (ETDEWEB)

    Caresta, Mauro, E-mail: mcaresta@yahoo.it [School of Mechanical and Manufacturing Engineering, The University of New South Wales, Sydney 2052, NSW (Australia); Wassink, David [Australian Nuclear Science and Technology Organisation (ANSTO), Lucas Heights 2234, NSW (Australia)

    2013-09-15

    Highlights: • A plate-type fuel assembly is made of thin plates mounted in a box-like structure. • Drag force from the coolant can shift the plates. • A non invasive method is proposed to test the strength of the plate connections. • The natural frequencies’ shift is used to assess the fuel integrity. -- Abstract: This work is concerned with the structural behaviour and the integrity of parallel plate-type nuclear fuel assemblies. A plate-type assembly consists of several thin plates mounted in a box-like structure and is subjected to a coolant flow that can result in a considerable drag force. A finite element model of an assembly is presented to study the sensitivity of the natural frequencies to the stiffness of the plates’ junctions. It is shown that the shift in the natural frequencies of the torsional modes can be used to check the global integrity of the fuel assembly while the local natural frequencies of the inner plates can be used to estimate the maximum drag force they can resist. Finally a non-destructive method is developed to assess the resistance of the inner plates to bear an applied load. Extensive computational and experimental results are presented to prove the applicability of the method presented.

  6. Influence of forest type and host plant genetic relatedness on the canopy arthropod community structure of Quercus crassifolia

    Scientific Electronic Library Online (English)

    Efraín, Tovar-Sánchez; Erwin, Martí-Flores; Leticia, Valencia-Cuevas; Patricia, Mussali-Galante.

    Full Text Available BACKGROUND: Quercus crassifolia is an oak species with characteristics of foundation species, which is a canopy dominant element of different forest types that supports a wide diversity of associated species. Therefore, it is an excellent system to address important ecological questions. We analyzed [...] the effect of individual genetic relatedness of the host plant, forest type (Abies-Quercus, Quercus-Pinus, and Quercus forest), and season (dry vs. rainy) on the canopy arthropod community structure. Thirty oak canopies were fogged (five individuals/season/forest type). RESULTS: We identified 442 arthropod species belonging to 22 orders. The highest values of density, diversity, and richness were recorded during the rainy season for each forest type. Also, the non-metric multidimensional scaling (NMDS) analysis showed a separation of the host tree species for each forest type. During the rainy season, the highest values of density, diversity, and richness in each forest type were recorded. A separation of host tree was found for each forest type. In general, diversity and richness of canopy arthropods showed the following pattern: Abies-Quercus > Quercus-Pinus > Quercus, while density showed an inverse pattern. An increase of the diversity of canopy arthropods is significantly related to an increase of host plant genetic diversity, independently of the type of forest and of the season. CONCLUSIONS: In terms of conservation, if arthropod species respond to genetic differences among host plants, it becomes important to conserve genetic diversity of foundation species, since it is fundamental to preserve diversity of their associated arthropod communities.

  7. Radio Structures of Seyfert Galaxies; 8, A Distance and Magnitude Limited Sample of Early-Type Galaxies

    CERN Document Server

    Nagar, N M; Mulchaey, J S; Gallimore, J F; Nagar, Neil M.; Wilson, Andrew S.; Mulchaey, John S.; Gallimore, Jack F.

    1999-01-01

    The VLA has been used at 3.6 and 20 cm to image a sample of about 50 early-type Seyfert galaxies with recessional velocities less than 7,000 km/s and total visual magnitude less than 14.5. The nuclear radio structures of Seyfert 2.0's in the early-type sample tend to be aligned with the [OIII] and Halpha+[NII] structures even though the radio extents are smaller than the [OIII] and Halpha+[NII] extents by a factor of ~2->5. This alignment, previously known for individual Seyferts with `linear' radio sources, is here shown to be characteristic of early-type Seyfert galaxies as a class. Seyfert 2.0's in the early-type sample also show a significant alignment between the emission-line ([OIII] and Halpha+[NII]) axes and the major axis of the host galaxy. These alignments are consistent with a picture in which the ionized gas represents ambient gas predominantly co-planar with the galaxy stellar disk. This ambient gas is ionized by nuclear radiation that may escape preferentially along and around the radio axis, a...

  8. First principles total energy calculations of the structural and electronic properties of YGe 2 in AlB 2 type structures

    Science.gov (United States)

    Ramírez, Alfredo; Cocoletzi, Gregorio H.; Takeuchi, Noboru

    2009-01-01

    We have performed first principles total energy calculations to investigate the structural and electronic properties of bulk YGe 2, in AlB 2 type configurations. Although the experimental stoichiometry is Y 2Ge 3, we have also considered the ideal YGe 2, and the Y 3Ge 5 configuration found for rare earth disilicides. Our studies using a unit cell with the ideal AlB 2 structure result in a lattice parameter a larger and a c/ a ratio smaller than the experimental values. On the other hand, the calculated structural parameters for the configurations with vacancies in the graphitic-like Ge planes are in excellent agreement with experimental values. The introduction of vacancies results in more favorable Y-Y and Ge-Y distances. The densities of states display p (of Ge) and d (of Y) orbital hybridizations, and they show that vacancies play an important role in the stability of the compound.

  9. The structure of Serratia marcescens Lip, a membrane-bound component of the type VI secretion system

    International Nuclear Information System (INIS)

    The high-resolution crystal structure of S. marcescens Lip reveals a new member of the transthyretin family of proteins. Lip, a core component of the type VI secretion apparatus, is localized to the outer membrane and is positioned to interact with other proteins forming this complex system. Lip is a membrane-bound lipoprotein and a core component of the type VI secretion system found in Gram-negative bacteria. The structure of a Lip construct (residues 29–176) from Serratia marcescens (SmLip) has been determined at 1.92 Å resolution. Experimental phases were derived using a single-wavelength anomalous dispersion approach on a sample cocrystallized with iodide. The membrane localization of the native protein was confirmed. The structure is that of the globular domain lacking only the lipoprotein signal peptide and the lipidated N-terminus of the mature protein. The protein fold is dominated by an eight-stranded ?-sandwich and identifies SmLip as a new member of the transthyretin family of proteins. Transthyretin and the only other member of the family fold, 5-hydroxyisourate hydrolase, form homotetramers important for their function. The asymmetric unit of SmLip is a tetramer with 222 symmetry, but the assembly is distinct from that previously noted for the transthyretin protein family. However, structural comparisons and bacterial two-hybrid data suggest that the SmLip tetramer is not relevant to its role as a core component of the type VI secretion system, but rather reflects a propensity for SmLip to participate in protein–protein interactions. A relatively low level of sequence conservation amongst Lip homologues is noted and is restricted to parts of the structure that might be involved in interactions with physiological partners

  10. MWW-type titanosilicate synthesis, structural modification and catalytic applications to green oxidations

    CERN Document Server

    Wu, Peng; Xu, Le; Liu, Yueming; He, Mingyuan

    2013-01-01

    This book provides a comprehensive review of a new generation of selective oxidation titanosilicate catalysts with the MWW topology (Ti-MWW) based on the research achievements of the past 12 years. It gives an overview of the synthesis, structure modification and catalytic properties of Ti-MWW. Ti-MWW can readily be prepared by means of direct hydrothermal synthesis with crystallization-supporting agents, using dual-structure-directing agents and a dry-gel conversion technique. It also can be post-synthesized through unique reversible structure transformation and liquid-phase isomorphous subst

  11. Electronic structure of Cr1-dS (d=0,0.17) with NiAs-type crystal structure

    OpenAIRE

    Koyama, M; Sato, H; Ueda, Y.; Hirai, C.; Taniguchi, M.

    2002-01-01

    Valence-band and conduction-band electronic structure of CrS (d=0) and Cr5S6 (d=0.17) has been investigated by means of photoemission and inverse-photoemission spectroscopies. Bandwidth of the valence bands of Cr5S6 (8.5 eV) is wider than that of CrS (8.1 eV), though the Cr 3d partial density of states evaluated from the Cr 3p-3d resonant photoemission spectroscopy is almost unchanged between the two compounds with respect to the shapes including binding energies. The Cr 3d ...

  12. Special types of FBG and CoaxBG structures for telecommunication and monitoring systems

    Science.gov (United States)

    Morozov, Oleg G.; Nasybullin, Aidar R.; Morozov, Gennady A.; Danilaev, Maxim P.; Zastela, Mikhail Y.; Farkhutdinov, Rafael V.; Faskhutdinov, Lenar M.

    2015-03-01

    The technology of fiber Bragg gratings is used as one of the most applicable technologies for construction of fiber optic sensors and telecommunication systems. Periodic irregular wave resistance located in the guiding waveguide can be regarded as analog of the fiber Bragg grating structure in the field of radio-frequency. Coaxial waveguide can be used as a guide system, so a special case of this structure is the Bragg grating on coaxial cable. Recently, the special structure of sensors were beginning to be used with heterogeneity as a discrete phase ?-shift. Based on the properties analysis of the Bragg reflection characteristics of structures with a phase shift in the optical and microwave range shown advantage of using these devices in measuring systems.

  13. Structure diversity in three forest types of north-eastern Thailand (Sakaerat Reserve, Pak Tong Chai)

    OpenAIRE

    Malaisse F.; Gajaseni J.; Lamotte S.

    1998-01-01

    The aim of the present study is to provide a basic knowledge in view of a better understanding of the global structure of threetropical forests at the Sakaerat Environmental Research Station (Pak Tong Chai district, Northeastern Thailand): a drydipterocarp forest (DDF), a dry evergreen forest (DEF) and an intermediate stage (DDFwf), characterized by the absence offire since 29 years in a pyro-climax. These forest ecosystems were contrasted by the composition and floristic structure, thebasal ...

  14. Metacommunity structuring in stream networks: roles of dispersal mode, distance type, and regional environmental context

    OpenAIRE

    Grönroos, Mira; Heino, Jani; Siqueira, Tadeu; Landeiro, Victor L.; Kotanen, Juho; Bini, Luis M.

    2013-01-01

    Within a metacommunity, both environmental and spatial processes regulate variation in local community structure. The strength of these processes may vary depending on species traits (e.g., dispersal mode) or the characteristics of the regions studied (e.g., spatial extent, environmental heterogeneity). We studied the metacommunity structuring of three groups of stream macroinvertebrates differing in their overland dispersal mode (passive dispersers with aquatic adults; passive dispersers wit...

  15. Magnetoelectric properties of multiferroic composites with pseudo-1-3-type structure

    Science.gov (United States)

    Shi, Zhan; Nan, Ce-Wen; Zhang, Jie; Ma, Jing; Li, Jing-Feng

    2006-06-01

    A pseudo-1-3-type multiferroic composite consisting of Pb(Zr,Ti)O3 (PZT) rod array (with base) and Terfenol-D/epoxy matrix was prepared by the dice-and-fill technique. Simple series and parallel mixture rules well described the measured dielectric and piezoelectric constants. Large magnetoelectric coefficients were observed in the pseudo-1-3-type composite, e.g., over 300 mV/cm Oe below 40 kHz and over 4500 mV/cm Oe at resonant frequency. The magnetoelectric response strongly depends on the magnetostrictive behavior of the matrix and the volume fraction of PZT rods, which gives us two convenient ways to modify their magnetoelectric response. For this pseudo 1-3-type multiferroic composite, the remarkable magnetoelectric response and well-developed fabrication technique are advantageous for their practical applications in piezoelectric-magnetoelectric multifunctional devices and large bandwidth magnetic sensors.

  16. Differences in the number of antennal sensory structures of males of three honey bee types

    Directory of Open Access Journals (Sweden)

    STORT A. C.

    1999-01-01

    Full Text Available The number of sensilla campaniformia and sensilla coeloconica + sensilla ampullacea of flagellomeres 2 to 11 of the antennae of three types of males (Italian, African and Africanized was determined by scanning electron microscopy. Comparison of the three male types showed that Italian males did not differ from African males in number of sensilla coeloconica + sensilla ampullacea and that both differed from Africanized males in terms of flagellomere 11. With respect to flagellomeres 3 and 10, Italian males were similar to Africanized males and both differed from African males. No differences between the three male types were detected in the other flagellomeres. In relation to the number of sensilla campaniformia Italian males differed of the African and Africanized males with respect to flagellomere 11.

  17. Type and structure of time-like singularities in general relativity theory

    International Nuclear Information System (INIS)

    A method is proposed which permits one to deterMine whether a time-like singularity refers to a point, linear or some other type of gravitational field singularity. It is shown that in the general theory of relativity an altogether different type of source may be possible which does not have any analogs in finite curvature space. An analysis is made of a number of solutions containing time-like singularities whose type varies depending on the sign of the functions involved in the solutions. The form of the solution near simple linear sources and of generalized anisotropic solutions is determined more accurately. The space-time described by the ?-metric is investigated completely and the form of the metric near the ends and at singular points of linear Weyl singularities is found

  18. Structural control over conductivity and conduction type in thin films of polyphenylquinones

    International Nuclear Information System (INIS)

    Carrier transport in newly synthesized 2,6-polyphenylquinolines containing an oxygen or phenylamine bridge group between phenylquinoline moieties and alkylated derivatives of carbazole or indolo[3,2-b]carbazole as an arylene radical has been studied. Both electron and hole transport is observed in films of all the polymers studied, with mobility on the order of 10?16 cm2 V?1 s?1, which increases on passing from an oxygen-to a phenylamine-type bridging group and from carbazole-to indolocarbazole-based derivatives. It is demonstrated that the conductivity and conduction type can be controlled by varying the type (oxygen or phenylamine) of bridging group between the phenylquinoline moieties or by the selection of an arylene radical.

  19. The structure of Serratia marcescens Lip, a membrane-bound component of the type VI secretion system.

    Science.gov (United States)

    Rao, Vincenzo A; Shepherd, Sharon M; English, Grant; Coulthurst, Sarah J; Hunter, William N

    2011-12-01

    Lip is a membrane-bound lipoprotein and a core component of the type VI secretion system found in Gram-negative bacteria. The structure of a Lip construct (residues 29-176) from Serratia marcescens (SmLip) has been determined at 1.92 Å resolution. Experimental phases were derived using a single-wavelength anomalous dispersion approach on a sample cocrystallized with iodide. The membrane localization of the native protein was confirmed. The structure is that of the globular domain lacking only the lipoprotein signal peptide and the lipidated N-terminus of the mature protein. The protein fold is dominated by an eight-stranded ?-sandwich and identifies SmLip as a new member of the transthyretin family of proteins. Transthyretin and the only other member of the family fold, 5-hydroxyisourate hydrolase, form homotetramers important for their function. The asymmetric unit of SmLip is a tetramer with 222 symmetry, but the assembly is distinct from that previously noted for the transthyretin protein family. However, structural comparisons and bacterial two-hybrid data suggest that the SmLip tetramer is not relevant to its role as a core component of the type VI secretion system, but rather reflects a propensity for SmLip to participate in protein-protein interactions. A relatively low level of sequence conservation amongst Lip homologues is noted and is restricted to parts of the structure that might be involved in interactions with physiological partners. PMID:22120744

  20. STRUCTURAL PERFORMANCE OF TWO TYPES OF WALL SLAB CONNECTION UNDER OUT-OF-PLANE LATERAL CYCLIC LOADING

    Directory of Open Access Journals (Sweden)

    AHMED ABDULRAZZAQ NASSER AL-AGHBARI

    2012-04-01

    Full Text Available Currently, most of the high-rise buildings in Malaysia are constructed using tunnel form system. However, this type of structural system is still questionable of its safety under ground motion. Thus, the main objective of this study is to test and compare the structural performance of two types of wall-slab connection namely cross and anchorage bracings under reversible quasi-static cyclic loading. Two identical sub-assemblage of wall-slab connections are designed, constructed and tested in heavy structural laboratory. A load actuator together with load cell was positioned horizontally at the upper part of the wall for applying the lateral cyclic load. The experimental result shows that the anchorage bracing connection has higher strength, higher ductility, better energy absorption and less structural damage as compared to cross-bracing connections. Based on this experiment, the ductility of anchorage bracing connection is m=6 which satisfies the requirement of ductility for seismic code of practice. Anchorage bracing connection can resist earthquake loading better than cross-bracing connections. Therefore, it is recommended to the construction industry to adopt this kind of design together with the detailing which consists of double layer of wire fabric at the connections. As a conclusion, the anchorage bracing connection has better seismic performance as compared to cross-bracing connection under lateral cyclic loading.

  1. Practical approaches to evaluate seismic adequacy of structures and equipment of already existing WWER-type nuclear power plants

    International Nuclear Information System (INIS)

    The seismic safety of the WWER-type NPPs was recognized as one of the most important safety issues due to almost no original seismic design and qualification of these NPPs and their structures and equipment in particular. There was no or almost no original seismic design and qualification with these NPPs and their equipment. Therefore, the main objective of the seismic re-evaluation and re-qualification program of the WWER-type NPPs is currently to enhance the seismic safety of these plants to the level generally accepted by the international community and in compliance with the currently valid standards and recognized practice, information and data available to date. Such a program has usually two important phases: the seismic safety assessment of the plant (structures and equipment) with identification of corrective measures, if required; and the design and implementation of these upgrading measures. The basic idea is to carry out a refined review of the original design and state of structures and equipment 'as built or as mounted' to identify the real safety margins of these structures and equipment and the possibility to use such initial conservatism to guarantee an adequate safety margin, as far as possible, even to a new seismic conditions. he seismic safety assessment should use conservatism in a very careful way. An extensive use of conservative assumptions in a re-evaluation or re-qualification phase can easily lead to the conclusion of very expensive or an unfeasible upgrading program. The seismic re-evaluation and re-qualification program should adopt a safety margin policy to avoid that a high conservatism in the seismic task gives the illusion of high safety margin in the overall plant design. The limited residual life of the plant should also be considered. On the other side, the higher design-based conservatism should always be used for all newly designed and newly installed structures, equipment and also for any physical modifications of the already existing structures and equipment. The practical approaches described in this presentation have been used and still are used by S and A-CZ for seismic re-evaluation and re/qualification of structures, equipment components and distribution systems installed on operating WWER-Type NPPs in several countries (Czech and Slovak Republics, Hungary). It is anticipated that these procedures will become a more or less standard for verification of seismic adequacy of their structures and equipment

  2. Investigations of nanoreactors on the basis of p-type porous silicon: Electron structure and phase composition

    International Nuclear Information System (INIS)

    Investigations of the electron structure and phase composition of the surface layers in porous silicon with a developed system of nanopores were made with the use of ultrasoft X-ray spectroscopy and X-ray photoelectron spectroscopy. The samples of porous silicon were obtained on the substrates with p-type conductivity under different modes of electrochemical etching. Porous surface layer represents a system of weakly connected pores oriented mainly perpendicular to the surface of silicon wafer. The mean transverse pore dimension is of ?50 nm. Silicon dioxide and sub-oxide were found in porous layer. We assume that these phases cover pores surface thus providing a possibility of the use of the structures as nanoreactors. -- Highlights: ? Nanoporous silicon layers were obtained. ? A system of weakly connected pores was detected. ? Electron structure and phase composition of the surface layers in porous silicon were investigated.

  3. In situ environment rather than substrate type dictates microbial community structure of biofilms in a cold seep system

    Science.gov (United States)

    Lee, On On; Wang, Yong; Tian, Renmao; Zhang, Weipeng; Shek, Chun Shum; Bougouffa, Salim; Al-Suwailem, Abdulaziz; Batang, Zenon B.; Xu, Wei; Wang, Guang Chao; Zhang, Xixiang; Lafi, Feras F.; Bajic, Vladmir B.; Qian, Pei-Yuan

    2014-01-01

    Using microscopic and molecular techniques combined with computational analysis, this study examined the structure and composition of microbial communities in biofilms that formed on different artificial substrates in a brine pool and on a seep vent of a cold seep in the Red Sea to test our hypothesis that initiation of the biofilm formation and spreading mode of microbial structures differs between the cold seep and the other aquatic environments. Biofilms on different substrates at two deployment sites differed morphologically, with the vent biofilms having higher microbial abundance and better structural features than the pool biofilms. Microbes in the pool biofilms were more taxonomically diverse and mainly composed of various sulfate-reducing bacteria whereas the vent biofilms were exclusively dominated by sulfur-oxidizing Thiomicrospira. These results suggest that the redox environments at the deployment sites might have exerted a strong selection on microbes in the biofilms at two sites whereas the types of substrates had limited effects on the biofilm development.

  4. In situ environment rather than substrate type dictates microbial community structure of biofilms in a cold seep system

    KAUST Repository

    Lee, O.O.

    2014-01-08

    Using microscopic and molecular techniques combined with computational analysis, this study examined the structure and composition of microbial communities in biofilms that formed on different artificial substrates in a brine pool and on a seep vent of a cold seep in the Red Sea to test our hypothesis that initiation of the biofilm formation and spreading mode of microbial structures differs between the cold seep and the other aquatic environments. Biofilms on different substrates at two deployment sites differed morphologically, with the vent biofilms having higher microbial abundance and better structural features than the pool biofilms. Microbes in the pool biofilms were more taxonomically diverse and mainly composed of various sulfate-reducing bacteria whereas the vent biofilms were exclusively dominated by sulfur-oxidizing Thiomicrospira. These results suggest that the redox environments at the deployment sites might have exerted a strong selection on microbes in the biofilms at two sites whereas the types of substrates had limited effects on the biofilm development.

  5. Design and Fabrication of 3D-Structured Contactless Capacitive-Type Detector for Capillary Electrophoresis Microchip

    International Nuclear Information System (INIS)

    Using simple and reliable microfabrication techniques, this study develops a capillary electrophoresis (CE) microchip with 3-dimensional-structured (3D-structured) contactless capacitive detector electrodes mounted parallel to the separation channel. The offchannel electrodes are deposited by Au sputtering and patterned using a standard 'lift-off' process. A vacuum fusion bonding process is employed to seal the lower substrate containing the microchannels and electrodes to an upper glass cover plate. The variation in the capacitance between the electrodes in the side channels is measured as different samples and ions pass through the detection region of the CE separation channel. Samples of Rhodamine B and a commercial sports drink are mixed in different buffer solutions and successfully separated and detected using the developed device. The 3D-structured contactless capacitive-type detection device has microscale dimensions and provides a valuable contribution to the realization of the lab-on-a-chip concept

  6. Affine crystal structure on rigged configurations of type D_n^(1)

    CERN Document Server

    Okado, Masato; Schilling, Anne

    2011-01-01

    Extending the work arXiv:math/0509194, we introduce the affine crystal action on rigged configurations which is isomorphic to the Kirillov-Reshetikhin crystal B^{r,s} of type D_n^(1) for any r,s. We also introduce a representation of B^{r,s} (r not equal to n-1,n) using tableaux of rectangular shape r x s, which are obtained from a column splitting procedure that was effectively used for type A to construct a bijection from elements of a tensor product of Kirillov-Reshetikhin crystals to rigged configurations.

  7. Structural characterization of cup-stacked-type nanofibers with an entirely hollow core

    Science.gov (United States)

    Endo, M.; Kim, Y. A.; Hayashi, T.; Fukai, Y.; Oshida, K.; Terrones, M.; Yanagisawa, T.; Higaki, S.; Dresselhaus, M. S.

    2002-02-01

    Straight long carbon nanofibers with a large hollow core obtained by a floating reactant method show a stacking morphology of truncated conical graphene layers, which in turn exhibit a large portion of open edges on the outer surface and also in the inner channels. Through a judicious choice of oxidation conditions, nanofibers with increased active edge sites are obtained without disrupting the fiber's morphology. A graphitization process induces a morphological change from a tubular type to a reversing saw-toothed type and the formation of loops along the inner channel of the nanofibers, accompanied by a decrease in interlayer spacing.

  8. Design of inorganic compounds with tetrahedral anions

    International Nuclear Information System (INIS)

    Some aspects in simulating compositions and properties of inorganic compounds with tetrahedral anions are considered on the basis of crystal-chemical data. Analysis of six structural types (glaserite, ?-K2SO4, bredigite, palmierite, NASICON, and whitlockite) was used to suggest a possible algorithm for application of crystal-chemical data to simulating composition, structure, and properties of new compounds. The significance of such data for solving various problems in material technology is demonstrated. 208 refs.; 13 figs.; 6 tabs

  9. Changes in the structural and biochemical composition of the arterial wall in type 2 diabetes patients

    DEFF Research Database (Denmark)

    RØrdam Preil, Simone

    2015-01-01

    Arteriel stivhed er et normalt aldersbetinget fænomen. Hos patienter med type 2 diabetes synes udviklingen af arteriel stivhed accelereret, hvilket kunne være årsagen til den forøgede incidens af kardiovaskulære sygdomme hos disse patienter. Ophobningen af kollagen og/eller nedbrydningen af elastin i den diabetiske arterievæg kunne ligge til grund for den arterielle stivhed hos patienter med type 2. Disse strukturelle ændringer mangler dog at blive undersøgt i humane arterier. I det første studie var formålet derfor at identificere histologisk forandringer i den strukturelle sammensætning af ikke-atherosclerotisk arterievæv fra patienter med og uden type 2 diabetes. Arteriesnittene fra mammaria arterierne blev farvet for makrofager, elastin, kollagen og ? smooth muscle actin, hvorefter vi målte området for kollagen og elastin og antallet af celler, der farves for ? smooth muscle actin, ved hjælp af histomorphometrisk analyser i lagene tunica intima, media og de luminale 30 ?m af adventitia. De histologiske undersøgelser viste, at der ikke var nogen makrofag infiltreringer i de tre lag, og at der ikke var nogen forskel på de elastin farvede områder. Dog var antallet af celler i adventitia laget signifikant lavere hos patienter med diabetes, og kollagen farvningen viste et større farvet område i intima og media lagene hos type 2 diabetes patienter end for patienterne uden diabetes. Ydermere forholder det sig således, at størstedelen af patienter med type 2 diabetes bliver behandlet med medikamentet metformin. Udover at have en glukose sænkende effekt menes det ligeledes at påvirke det kardiovaskulære system positivt. For at undersøge hvilke komponenter af arterievæggen metformin influerer på, besluttede vi os for at lave en kvantitative proteom analyse i det andet studie. Studie II og studie I er foretaget på det samme patient materiale. Denne gang blev der brugt et enkelt vævssnit til proteom undersøgelsen. Resultaterne fra dette forsøg viste, at mængden af kollagen type IV blandt andet var forøget hos patienter med type 2 diabetes sammenlignet med patienter uden diabetes. De viste ligeledes, at metformin havde en normaliserende effekt på den arterielle protein sammensætning hos patienter med type 2 diabetes. For at se nærmere på den accelererede udvikling af arteriel stivhed hos patienter med type 2 diabetes besluttede vi at undersøge rygningens og calpain-1´s betydning for elastin nedbrydningen. Flere studier har vist, at rygning påvirker den arterielle stivhed, mens andre studier peger mod, at cystein proteasen calpian-1 øger mængden af matrix metalloproteinasen 2 (MMP-2), som nedbryder bl.a. elastin. Vores hypotese i studie III gik både ud på, at calpain-1 kunne være forøget hos patienter med type 2 diabetes, hvorved den vil føre til forøget kollagen indhold, forøget MMP-2 og reduceret elastin i arterierne, og at rygning kunne have en indvirkning på mængden af disse molekyler. Niveauet af MMP-2, calpain-1 og actin ? smooth muscle blev målt ved hjælp af western blotting i mammaria arterier fra patienter medog uden diabetes. De tilovers blivende vævs rester blev derefter hydrolyseret for at måle elastin fragmentet desmosine med liquid chromatography og mass spectrometry (LC-MS), mens kollagen indholdet blev målt ved brug af et hydroxyproline assay. Resultaterne viste, at diabetes ikke påvirkede mængden af calpain-1, MMP-2, desmosine og hydroxyproline i den human arterie væg, mens mængden af desmosine var nedsat i arterier fra ryger og tidligere rygere sammenlignet med ikke rygere. Et andet protein der ligeledes er involveret i den strukturelle sammensætning af arterievæggen er lysyl oxidase (LOX), som krydsbinder henholdsvis elastin og kollagen. Forskellige undersøgelser har vist, at diabetes kunne øge mængden af LOX, hvilket ligeledes er blevet vist for MMP-2. Hvis dette skulle være sandt, ville vi antage at LOX kunne øge krydsbindingen af kollagen, mens MMP-2 øgede nedbrydningen af elastin i patienter med type 2 diabetes. Derfor bestemte vi os i

  10. Wild-type and met-65-->Leu variants of human cystatin A are functionally and structurally identical.

    Science.gov (United States)

    Craven, C J; Baxter, N J; Murray, E H; Hill, N J; Martin, J R; Ylinenjärvi, K; Björk, I; Waltho, J P; Murray, I A

    2000-12-26

    The solution structure of an N-terminally truncated and mutant form (M65L(2-98)) of the human cysteine protease inhibitor cystatin A has been reported that reveals extensive structural differences when compared to the previously published structure of full-length wild-type (WT) cystatin A. On the basis of the M65L(2-98) structure, a model of the inhibitory mechanism of cystatin A was proposed wherein specific interactions between the N- and C-terminal regions of cystatin A are invoked as critical determinants of protease binding. To test this model and to account for the reported differences between the two structures, we undertook additional structural and mechanistic analyses of WT and mutant forms of human cystatin A. These show that modification at the C-terminus of cystatin A by the addition of nine amino acids has no effect upon the affinity of papain inhibition (K(D) = 0.18+/-0.02 pM) and the consequences of such modification are not propagated to other parts of the structure. These findings indicate that perturbation of the C-terminus can be achieved without any measurable effect on the N-terminus or the proteinase binding loops. In addition, introduction of the methionine-65 --> leucine substitution into cystatin A that retains the N-terminal methionine (M65L(1-98)) has no significant effect upon papain binding (K(D) = 0.34+/-0.02 pM). Analyses of the structures of WT and M65L(1-98) using (1)H NMR chemical shifts and residual dipolar couplings in a partially aligning medium do not reveal any evidence of significant differences between the two inhibitors. Many of the differences between the published structures correspond to major violations by M65L(2-98) of the WT constraints list, notably in relation to the position of the N-terminal region of the inhibitor, one of three structural motifs indicated by crystallographic studies to be involved in protease binding by cystatins. In the WT structure, and consistent with the crystallographic data, this region is positioned adjacent to another inhibitory motif (the first binding loop), whereas in M65L(2-98) there is no proximity of these two motifs. As the NMR data for both WT9C and M65L(1-98) are wholly consistent with the published structure of WT cystatin A and incompatible with that of M65L(2-98), we conclude that the former represents the most reliable structural model of this protease inhibitor. PMID:11123903

  11. On the prolongation structures of Petrov type III vacuum spacetime equations

    OpenAIRE

    Ifidon, E. O.

    2009-01-01

    The universal covering symmetry algebra of the Robinson-Trautman equations of Petrov Type III is shown to include the infinite-dimensional affine Kac-Moody algebra A_1 as a prolongation algebra. This algebra has slower growth than the contragradient algebra K_2 obtained previously for this equation.

  12. Psychological Type, Decision-Making Style, and Reactions to Structured Career Interventions.

    Science.gov (United States)

    Tinsley, Howard E. A.; Tinsley, Diane J.; Rushing, James

    2002-01-01

    An intervention for 50 career-undecided women helped them identify decision-making barriers, consider vocational interests, and formulate provisional major and career choices. Women who were introverted and whose decision-making style was rational reported greater benefits from the intervention than those whose personality type was perceiving and…

  13. Low-cycle fatigue of structural materials for manufacture of WWER type power plant components

    International Nuclear Information System (INIS)

    The results are summed up of testing low-cycle fatigue of materials used for valves and fittings for WWER type power plants. The results are also reported of testing material 10GN2MFA developed for WWER-1000 reactors, mainly for steam generators, pressurizers, water tanks and pipes. (B.S.)

  14. Aeschynite and euxenite structure-types as host phases for rare-earths and actinides from HLW

    International Nuclear Information System (INIS)

    Aeschynite and euxenite structure-types are proposed as host phases for rare earth elements and actinides. Aeschynite and euxenite structure types are represented by the general formula: (REE, Y, Th, U, Ca)(Ti, Nb, Ta)2O6. In both structure-types, a variety of large cations such as rare-earths and actinides can be accommodated in the tunnels of connected holes in aeschynite or the interlayer space in euxenite. The waste loadings (rare-earths and actinides) in aeschynite and euxenite are at least 40 wt.% based on chemical compositions of naturally occurring aeschynite and euxenite. The sol-gel method has been successfully used to prepare aeschynite and euxenite as preferred crystalline ceramics. The aged gels and finally calcined products have been characterized by infrared and Raman spectroscopy, differential thermal analysis, and X-ray diffraction analysis. The fabrication technology of aeschynite and euxenite type ceramics is feasible by using hot-pressing as a final processing stage. The mechanistic processes of aeschynite and euxenite formation by the sol-gel method as described as REE(OH)3·Nb(OH)5·Ti(OH)4 coprecipitation; the polymerization of Nb and Ti hydroxides to form isolated (Nb,Ti)2O10 di-octahedra through oxygen and hydroxyl bridges accompanied by a dehydration reaction; welding together of isolated pieces of (Nb,Ti)2O10 to form longer (Nb,Ti)2Osub> to form longer (Nb,Ti)2O10 di-octahedral chains; REE being connected to the dioctahedral chains through oxygen and hydroxyl bridges; and to gradually form small three-dimensional nucleates of aeschynite and euxenite. Critical data from the literature on radiation effects and secondary alteration are reviewed as a part of the evaluation of the long-term performance of these phases

  15. Impact of type 2 diabetes and the metabolic syndrome on myocardial structure and microvasculature of men with coronary artery disease

    Directory of Open Access Journals (Sweden)

    Yii Michael

    2011-09-01

    Full Text Available Abstract Background Type 2 diabetes and the metabolic syndrome are associated with impaired diastolic function and increased heart failure risk. Animal models and autopsy studies of diabetic patients implicate myocardial fibrosis, cardiomyocyte hypertrophy, altered myocardial microvascular structure and advanced glycation end-products (AGEs in the pathogenesis of diabetic cardiomyopathy. We investigated whether type 2 diabetes and the metabolic syndrome are associated with altered myocardial structure, microvasculature, and expression of AGEs and receptor for AGEs (RAGE in men with coronary artery disease. Methods We performed histological analysis of left ventricular biopsies from 13 control, 10 diabetic and 23 metabolic syndrome men undergoing coronary artery bypass graft surgery who did not have heart failure or atrial fibrillation, had not received loop diuretic therapy, and did not have evidence of previous myocardial infarction. Results All three patient groups had similar extent of coronary artery disease and clinical characteristics, apart from differences in metabolic parameters. Diabetic and metabolic syndrome patients had higher pulmonary capillary wedge pressure than controls, and diabetic patients had reduced mitral diastolic peak velocity of the septal mitral annulus (E', consistent with impaired diastolic function. Neither diabetic nor metabolic syndrome patients had increased myocardial interstitial fibrosis (picrosirius red, or increased immunostaining for collagen I and III, the AGE N?-(carboxymethyllysine, or RAGE. Cardiomyocyte width, capillary length density, diffusion radius, and arteriolar dimensions did not differ between the three patient groups, whereas diabetic and metabolic syndrome patients had reduced perivascular fibrosis. Conclusions Impaired diastolic function of type 2 diabetic and metabolic syndrome patients was not dependent on increased myocardial fibrosis, cardiomyocyte hypertrophy, alteration of the myocardial microvascular structure, or increased myocardial expression of N?-(carboxymethyllysine or RAGE. These findings suggest that the increased myocardial fibrosis and AGE expression, cardiomyocyte hypertrophy, and altered microvasculature structure described in diabetic heart disease were a consequence, rather than an initiating cause, of cardiac dysfunction.

  16. Community structure of skipper butterflies (Lepidoptera, Hesperiidae) along elevational gradients in Brazilian Atlantic forest reflects vegetation type rather than altitude.

    Science.gov (United States)

    Carneiro, Eduardo; Mielke, Olaf Hermann Hendrik; Casagrande, Mirna Martins; Fiedler, Konrad

    2014-01-01

    Species turnover across elevational gradients has matured into an important paradigm of community ecology. Here, we tested whether ecological and phylogenetic structure of skipper butterfly assemblages is more strongly structured according to altitude or vegetation type along three elevation gradients of moderate extent in Serra do Mar, Southern Brazil. Skippers were surveyed along three different mountain transects, and data on altitude and vegetation type of every collection site were recorded. NMDS ordination plots were used to assess community turnover and the influence of phylogenetic distance between species on apparent community patterns. Ordinations based on ecological similarity (Bray-Curtis index) were compared to those based on phylogenetic distance measures (MPD and MNTD) derived from a supertree. In the absence of a well-resolved phylogeny, various branch length transformation methods were applied together with four different null models, aiming to assess if results were confounded by low-resolution trees. Species composition as well as phylogenetic community structure of skipper butterflies were more prominently related to vegetation type instead of altitude per se. Phylogenetic distances reflected spatial community patterns less clearly than species composition, but revealed a more distinct fauna of monocot feeders associated with grassland habitats, implying that historical factors have played a fundamental role in shaping species composition across elevation gradients. Phylogenetic structure of community turned out to be a relevant additional tool which was even superior to identify faunal contrasts between forest and grassland habitats related to deep evolutionary splits. Since endemic skippers tend to occur in grassland habitats in the Serra do Mar, inclusion of phylogenetic diversity may also be important for conservation decisions. PMID:25272004

  17. Early type galaxies and structural parameters from ESO public survey KiDS

    CERN Document Server

    Roy, N; La Barbera, F; Tortora, C; Getman, F; Radovich, M; Capaccioli, M

    2015-01-01

    The Kilo Degree survey (KiDS) is a large-scale optical imaging survey carried out with the VLT Survey Telescope (VST), which is the ideal tool for galaxy evolution studies. We expect to observe millions of galaxies for which we extract the structural parameters in four wavebands (u, g, r and i). This sample will represent the largest dataset with measured structural parameters up to a redshift $z=0.5$. In this paper we will introduce the sample, and describe the 2D fitting procedure using the 2DPHOT environment and the validation of the parameters with an external catalog.

  18. Structure of the Rotor Ring of F-Type NA+-ATPase from Ilyobacter tartaricus

    OpenAIRE

    Meier, Thomas; Polzer, Patrick; Diederichs, Kay; Welte, Wolfram; Dimroth, Peter

    2005-01-01

    In the crystal structure of the membrane-embedded rotor ring of the sodium ion translocating adenosine 5¶-triphosphate (ATP) synthase of Ilyobacter tartaricus at 2.4 angstrom resolution, 11 c subunits are assembled into an hourglass-shaped cylinder with 11-fold symmetry. Sodium ions are bound in a locked conformation close to the outer surface of the cylinder near the middle of the membrane. The structure supports an ion-translocation mechanism in the intact ATP synthase in which the binding...

  19. Structural characterization of spin type propagation products in the high temperature self propagating synthesis

    International Nuclear Information System (INIS)

    In the self-propagating high-temperature synthesis (S H S) of alumina-zirconia-niobium, different conditions producing combustion front propagation in spin mode have been found. For this purpose, in addition to dilution degree, a great importance of particle size of reactants has been shown. At this work, samples produced by spin propagation, under different conditions were analyzed with respect to the layer structure resulting of tis propagation mode, in both macroscopic and microscopic aspects. The observed structures and related propagation mode are discussed. (author)

  20. Structural Dimensions, Fabrication, Materials, and Operational History for Types I and II Waste Tanks

    International Nuclear Information System (INIS)

    Radioactive waste is confined in 48 underground storage tanks at the Savannah River Site. The waste will eventually be processed and transferred to other site facilities for stabilization. Based on waste removal and processing schedules, many of the tanks, including those with flaws and/or defects, will be required to be in service for another 15 to 20 years. Until the waste is removed from storage, transferred, and processed, the materials and structures of the tanks must maintain a confinement function by providing a leak-tight barrier to the environment and by maintaining acceptable structural stability during design basis event which include loading from both normal service and abnormal conditions

  1. Structure of the rotor ring of F-Type Na+-ATPase from Ilyobacter tartaricus.

    Science.gov (United States)

    Meier, Thomas; Polzer, Patrick; Diederichs, Kay; Welte, Wolfram; Dimroth, Peter

    2005-04-29

    In the crystal structure of the membrane-embedded rotor ring of the sodium ion-translocating adenosine 5'-triphosphate (ATP) synthase of Ilyobacter tartaricus at 2.4 angstrom resolution, 11 c subunits are assembled into an hourglass-shaped cylinder with 11-fold symmetry. Sodium ions are bound in a locked conformation close to the outer surface of the cylinder near the middle of the membrane. The structure supports an ion-translocation mechanism in the intact ATP synthase in which the binding site converts from the locked conformation into one that opens toward subunit a as the rotor ring moves through the subunit a/c interface. PMID:15860619

  2. Structural Dimensions, Fabrication, Materials, and Operational History for Types I and II Waste Tanks

    Energy Technology Data Exchange (ETDEWEB)

    Wiersma, B.J.

    2000-08-16

    Radioactive waste is confined in 48 underground storage tanks at the Savannah River Site. The waste will eventually be processed and transferred to other site facilities for stabilization. Based on waste removal and processing schedules, many of the tanks, including those with flaws and/or defects, will be required to be in service for another 15 to 20 years. Until the waste is removed from storage, transferred, and processed, the materials and structures of the tanks must maintain a confinement function by providing a leak-tight barrier to the environment and by maintaining acceptable structural stability during design basis event which include loading from both normal service and abnormal conditions.

  3. A Scenario for the Fine Structures of Solar Type IIIb Radio Bursts Based on the Electron Cyclotron Maser Emission

    CERN Document Server

    Wang, C B

    2015-01-01

    A scenario based on the electron cyclotron maser emission is proposed for the fine structures of solar radio emission in the present discussion. It is suggested that under certain conditions modulation of the ratio between the plasma frequency and electron gyro-frequency by ultra low frequency waves, which is a key parameter for excitation of the electron cyclotron maser instability, may lead to the intermittent emission of radio waves. As an example, the explanation of the observed fine-structure components in the solar type IIIb burst is discussed in detail. Three primary issues of the type IIIb bursts are addressed: 1) what is the physical mechanism that results in the intermittent emission elements that form a chain in the dynamic spectrum of type IIIb bursts, 2) what causes the split pair (or double stria) and the triple stria, 3) why in the events of fundamental-harmonic pair emission there is only IIIb-III, but IIIb-IIIb or III-IIIb cases are very rarely observed.

  4. Unusual weak magnetic exchange in two different structure types: YbPt2Sn and YbPt2In.

    Science.gov (United States)

    Gruner, T; Jang, D; Steppke, A; Brando, M; Ritter, F; Krellner, C; Geibel, C

    2014-12-01

    We present the structural, magnetic, thermodynamic and transport properties of the two new compounds YbPt(2)Sn and YbPt(2)In. X-ray powder diffraction shows that they crystallize in different structure types, the hexagonal ZrPt(2)Al and the cubic Heusler type, respectively. Despite quite different lattice types, both compounds present very similar magnetic properties: a stable trivalent Yb(3+), no evidence for a sizeable Kondo interaction and very weak exchange interactions with a strength below 1 K as deduced from specific heat C(T). Broad anomalies in C(T) suggest short range magnetic ordering at about 250 mK and 180 mK for YbPt(2)Sn and YbPt(2)In, respectively. The weak exchange and the low ordering temperature result in a large magnetocaloric effect as deduced from the magnetic field dependence of C(T), making these compounds interesting candidates for magnetic cooling. In addition we found in YbPt(2)In evidences for a charge density wave transition at about 290 K. The occurrence of such transitions within several RET2X compound series (RE = rare earth, T = noble metal, X = In, Sn) is analyzed. PMID:25322667

  5. Carrier type inversion in quasi-free standing graphene: studies of local electronic and structural properties.

    Science.gov (United States)

    Melios, Christos; Panchal, Vishal; Giusca, Cristina E; Strupi?ski, W?odek; Silva, S Ravi P; Kazakova, Olga

    2015-01-01

    We investigate the local surface potential and Raman characteristics of as-grown and ex-situ hydrogen intercalated quasi-free standing graphene on 4H-SiC(0001) grown by chemical vapor deposition. Upon intercalation, transport measurements reveal a change in the carrier type from n- to p-type, accompanied by a more than three-fold increase in carrier mobility, up to ?h???4540?cm(2)?V(-1)?s(-1). On a local scale, Kelvin probe force microscopy provides a complete and detailed map of the surface potential distribution of graphene domains of different thicknesses. Rearrangement of graphene layers upon intercalation to (n?+?1)LG, where n is the number of graphene layers (LG) before intercalation, is demonstrated. This is accompanied by a significant increase in the work function of the graphene after the H2-intercalation, which confirms the change of majority carriers from electrons to holes. Raman spectroscopy and mapping corroborate surface potential studies. PMID:26030153

  6. Structure and bonding of ternary gallides CaGa1-x(Si/Sn/Al/In)x with the CrB type and related structures

    International Nuclear Information System (INIS)

    The polar binary alkaline earth (AII) tetrelides AIIMIV are known to crystallize with the CrB type, where the two-bonded M atoms of planar zig-zag chains (6 v.e./M) are surrounded by stretched trigonal prisms of A cations. In contrast, in the only known isotypic trielide, CaGa (with only 5 v.e./M) these prisms are substantially compressed. Hence, the phase widths of mixed gallides/tetrelides AIIGa1-xMxIV (MIV=Si, Sn) forming the CrB structure type and mixed trielides CaGa1-x(Al/In)x of related types were studied synthetically, structurally and by theoretical calculations. All compounds were synthesized from stoichiometric mixtures of the elements and characterized by single crystal X-ray diffraction. DFT band structure calculations were carried out for the binary border compounds. In mixed tetrelides CaGa1-xSix, the phase width of the CrB type reaches from CaSi up to x=0.42; in CaSn the maximum of Ga substitution is 0.41, whereas nearly no tetrel substitution is observed in CaGa. The geometrical changes (inter- and intra-chain M-M distances) during these substitutions (involving reduction of v.e./M) as well as the observed substitution limits and the changes of the bonding character in the planar chains are explained by the results of the band structure calculations. Partial exchange of Ga in CaGa against Al or In results in a series of m against Al or In results in a series of mixed trielides with large monoclinic commensurately modulated superstructures of the CrB type: these phases, CaGa0.67Al0.33 (space group C2/c, a=2717.7(12), b=1159.9(3), c=607.4(2) pm, ?=92.42(3) deg., Z=36, R1=0.0374), CaGa0.84In0.16 (space group P21/c, a=1222.9(8), b=1167.9(5), c=612.0(3) pm, ?=95.24(3) deg., Z=16, R1=0.0558) and CaGa0.55In0.45 (space group P21/c, a=936.1(6), b=1188.1(9), c=618.5(3) pm, ?=101.73(4) deg., Z=12, R1=0.0793) show only very small phase widths. In their structures the b axis is unchanged with respect to the CrB type and the enlargement of the a-c basis can be described by a general transformation matrix. In all three structures, the M chains are of wavelike form, varying the inter-chain distances such that Al and In atoms tend to approach each other, whereas Ga tends to form short intra-chain distances while avoiding close inter-chain contacts

  7. The structural, electronic and dynamic properties of the L12- type Co3Ti alloy

    Science.gov (United States)

    Arikan, Nihat; Özduran, Mustafa

    2014-10-01

    The structural, electronic and dynamic properties of the cubic Co3Ti alloy in L12 structure have been investigated using a pseudopotential plane wave (PP-PW) method within the generalized gradient approximation proposed by Perdew-Burke-Ernzerhof (GGA-PBE). The structural properties, including the lattice constant, the bulk modulus and its pressure derivative agree reasonably with the previous results. The density of state (DOS), projected density of state (PDOS) and electronic band structure are also reported. The DOS shows that Co3Ti alloy has a metallic character since the energy bands cross the Fermi level. The density of states at Fermi level mainly comes from the Co-3d states. Phonon dispersion curves and their corresponding total densities of states were obtained using a linear response in the framework of the density functional perturbation theory. All computed phonon frequencies are no imaginer and thus, Co3Ti alloy is dynamically stable. The zone center phonon modes have been founded to be 9.307, 9.626 and 13.891 THz for Co3Ti.

  8. Adolescent Gender Differences in Social Support: Structure, Function, and Provider Type.

    Science.gov (United States)

    Colarossi, Lisa G.

    2001-01-01

    Survey data was used to examine gender differences in perceptions of support across three different constructs: structural support related to the number of adults versus friends; the quantity of support provided by mothers, fathers, peers, and teachers; satisfaction with support from friends and family. Implications for practice with adolescents…

  9. Complex Regional Pain Syndrome Type I Affects Brain Structure in Prefrontal and Motor Cortex

    OpenAIRE

    Pleger, Burkhard; Draganski, Bogdan; Schwenkreis, Peter; Lenz, Melanie; Nicolas, Volkmar; Maier, Christoph; Tegenthoff, Martin

    2014-01-01

    The complex regional pain syndrome (CRPS) is a rare but debilitating pain disorder that mostly occurs after injuries to the upper limb. A number of studies indicated altered brain function in CRPS, whereas possible influences on brain structure remain poorly investigated.

  10. Systems of force constants, Coriolis interaction constants and peculiarities of structure of XY4-type tetrahalides

    International Nuclear Information System (INIS)

    Regularities were considered of changing force constants of total valent force field of tetrahedral molecules of XCl4- and MHal4-type (where X = C, Si, Ge, Sn, Ti, Zr, Hf, V, Cr; M = Ti, Zr, Ge; Hal = F, Cl, Br, I). Dependences of force constant on mean energy of bond breaking and on intermolecular distance R(X-Y), as well as dependences between force constants, were considered

  11. Structural and functional properties of two types of horizontal cell in the skate retina

    OpenAIRE

    1990-01-01

    Two morphologically distinct types of horizontal cell have been identified in the all-rod skate retina by light- and electron- microscopy as well as after isolation by enzymatic dissociation. The external horizontal cell is more distally positioned in the retina and has a much larger cell body than does the internal horizontal cell. However, both external and internal horizontal cells extend processes to the photoreceptor terminals where they end as lateral elements adjacent to the synaptic r...

  12. Preliminary fuselage structural configuration of a flying-wing type airline

    OpenAIRE

    Cheng, Yun

    2012-01-01

    The flying-wing is a type of configuration which is a tailless airplane accommodating all of its parts within the outline of a single airfoil. Theoretically, it has the most aerodynamic efficiency. The fuel consumption can be more efficient than the existed conventional airliner. It seems that this configuration can achieve the above mentioned requirements. According to these outstanding advantages, many aircraft companies did a great deal of projects on the flying-wing concept. However, t...

  13. Engineering ?-cell islets or islet-like structures for type 1 diabetes treatment.

    Science.gov (United States)

    Liu, Xiaoyan; Li, Xiaowei; Zhang, Ning; Wen, Xuejun

    2015-07-01

    Type 1 diabetes mellitus is a disease characterized by the destruction of the ?-cells in the pancreatic islets of Langerhans. The current primary treatment for type 1 diabetes is insulin injections administered multiple times throughout the day. However, this treatment cannot provide sustained physiological release of insulin and the insulin amount is not finely tuned to the glycemia condition. Pancreatic transplantation or islet transplantation would be the preferred treatment strategy but the lack of donor tissue and immunoincompatibility has been shown to be a roadblock to their widespread use. Bioengineering strategies are poised to combat these challenges. Islet encapsulation is expected to offer both immunoisolation and immunomodulation effects by: (1) physically protecting islets from the attacks of immunoglobulins, complements, and host immune cells, and (2) delivering immune regulatory and immunomodulatory factors locally to the islets to protect those islets from immune rejection. Semi-permeable coatings using biocompatible biomaterials can be used for immunoisolating islets away from the host immune systems. Immunoisolation technology also provides an opportunity to use other cell sources for cell therapy to treat type 1 diabetes. Recently, some studies reported that co-transplantation of islets with mesenchymal stem cells (MSCs) can control graft inflammation. MSCs have immunomodulatory property. They are able to secrete anti-inflammatory factors and repress the activity of various immune cells. Growth factors like interleukin 10 (IL-10) and leukemia inhibitory factor (LIF) also have immune regulatory properties. Therefore immunoisolation and immunomodulation technologies can be integrated and applied to ?-cell encapsulation for the treatment of type 1 diabetes. Through engineering ?-cell islets or islet-like microtissues, the viability and function of transplanted ?-cells may be improved. In the meantime, the survival of transplanted ?-cells can be further improved by promoting vascular network formation surrounding the transplanted islets or microtissues. PMID:25892491

  14. NMR spin-echoes and the domain structure of Neel type nickel crystals

    International Nuclear Information System (INIS)

    NMR Fourier transform measurements have been performed at 4.2 K with a Neel type single crystal of Ni. It is shown, that the spin echoes arise from both domains and domain walls on the (110) planes. The wall signal correlates roughly with the number of walls. The domain signal and the corresponding enhancement factor etasub(d) are varying with the internal field. A theoretical description of this variation is given. (orig.)

  15. The controlling role of positive structures over the metallogenesis and emplacement of inter layer oxidation sandstone type uranium deposits

    International Nuclear Information System (INIS)

    The positive structures in this paper mean the geological structures related to the occurrence of U-metallogenic zones or U-deposit such as anticlines, uplifts and uplifted fault-blocks. Occurrence features of interlayer oxidation sandstone type deposit at the southern margin of Yili basin and southwestern margin of Turpan-Hami basin, the northeastern margin of Jiudong basin illustrate that the sandstone-hosted uranium deposits, the U-mineralized sections and the uranium occurrences are always selectively emplaced on/in positive structures. The reasons for this lie in the formation mechanism of sandstone-hosted U-deposits. The positive structures raised the elevation of ore-hosting sandstone horizon and make it close to ground surface or exposed at the ground surface, which result in the infiltration of uranium and oxygen bearing groundwater from recharge area into host sandstone horizon, and the interlayer oxidation of host sandstone, as well as the dissolution and the migration of uranium in host sandstone, and the reduction mineralization at the oxidation-reduction interface. Sufficient attention should be paid to the controlling role of positive structures over the metallogenesis and emplacement of sandstone-hosted uranium deposits. They could act as an important criterion for recognizing and prognosticating potential uranium mineralized areas in uranium metallogenic zones or uranium-productive sedimentary basins. (authors))

  16. Atomic resolution structure of cucurmosin, a novel type 1 ribosome-inactivating protein from the sarcocarp of Cucurbita moschata

    Energy Technology Data Exchange (ETDEWEB)

    Hou, Xiaomin; Meehan, Edward J.; Xie, Jieming; Huang, Mingdong; Chen, Minghuang; Chen, Liqing (UAH); (Fujian); (Chinese Aca. Sci.)

    2008-10-27

    A novel type 1 ribosome-inactivating protein (RIP) designated cucurmosin was isolated from the sarcocarp of Cucurbita moschata (pumpkin). Besides rRNA N-glycosidase activity, cucurmosin exhibits strong cytotoxicities to three cancer cell lines of both human and murine origins, but low toxicity to normal cells. Plant genomic DNA extracted from the tender leaves was amplified by PCR between primers based on the N-terminal sequence and X-ray sequence of the C-terminal. The complete mature protein sequence was obtained from N-terminal protein sequencing and partial DNA sequencing, confirmed by high resolution crystal structure analysis. The crystal structure of cucurmosin has been determined at 1.04 {angstrom}, a resolution that has never been achieved before for any RIP. The structure contains two domains: a large N-terminal domain composed of seven {alpha}-helices and eight {beta}-strands, and a smaller C-terminal domain consisting of three {alpha}-helices and two {beta}-strands. The high resolution structure established a glycosylation pattern of GlcNAc{sub 2}Man3Xyl. Asn225 was identified as a glycosylation site. Residues Tyr70, Tyr109, Glu158 and Arg161 define the active site of cucurmosin as an RNA N-glycosidase. The structural basis of cytotoxicity difference between cucurmosin and trichosanthin is discussed.

  17. Structure of a human monoclonal antibody Fab fragment against gp41 of human immunodeficiency virus type 1

    Science.gov (United States)

    He, Xiao M.; Rueker, Florian; Casale, Elena; Carter, Daniel C.

    1992-01-01

    The three-dimensional structure of a human monoclonal antibody (Fab), which binds specifically to a major epitope of the transmembrane protein gp41 of the human immunodeficiency virus type 1, has been determined by crystallographic methods to a resolution of 2.7 A. It has been previously determined that this antibody recognizes the epitope SGKLICTTAVPWNAS, belongs to the subclass IgG1 (kappa), and exhibits antibody-dependent cellular cytotoxicity. The quaternary structure of the Fab is in an extended conformation with an elbow bend angle between the constant and variable domains of 175 deg. Structurally, four of the hypervariable loops can be classified according to previously recognized canonical structures. The third hypervariable loops of the heavy (H3) and light chain (L3) are structurally distinct. Hypervariable loop H3, residues 102H-109H, is unusually extended from the surface. The complementarity-determining region forms a hydrophobic binding pocket that is created primarily from hypervariable loops L3, H3, and H2.

  18. The Structures of Coiled-Coil Domains from Type III Secretion System Translocators Reveal Homology to Pore-Forming Toxins

    Energy Technology Data Exchange (ETDEWEB)

    Barta, Michael L.; Dickenson, Nicholas E.; Patil, Mrinalini; Keightley, Andrew; Wyckoff, Gerald J.; Picking, William D.; Picking, Wendy L.; Geisbrecht, Brian V. (UMKC); (OKLU)

    2012-03-26

    Many pathogenic Gram-negative bacteria utilize type III secretion systems (T3SSs) to alter the normal functions of target cells. Shigella flexneri uses its T3SS to invade human intestinal cells to cause bacillary dysentery (shigellosis) that is responsible for over one million deaths per year. The Shigella type III secretion apparatus is composed of a basal body spanning both bacterial membranes and an exposed oligomeric needle. Host altering effectors are secreted through this energized unidirectional conduit to promote bacterial invasion. The active needle tip complex of S. flexneri is composed of a tip protein, IpaD, and two pore-forming translocators, IpaB and IpaC. While the atomic structure of IpaD has been elucidated and studied, structural data on the hydrophobic translocators from the T3SS family remain elusive. We present here the crystal structures of a protease-stable fragment identified within the N-terminal regions of IpaB from S. flexneri and SipB from Salmonella enterica serovar Typhimurium determined at 2.1 {angstrom} and 2.8 {angstrom} limiting resolution, respectively. These newly identified domains are composed of extended-length (114 {angstrom} in IpaB and 71 {angstrom} in SipB) coiled-coil motifs that display a high degree of structural homology to one another despite the fact that they share only 21% sequence identity. Further structural comparisons also reveal substantial similarity to the coiled-coil regions of pore-forming proteins from other Gram-negative pathogens, notably, colicin Ia. This suggests that these mechanistically separate and functionally distinct membrane-targeting proteins may have diverged from a common ancestor during the course of pathogen-specific evolutionary events.

  19. Type V collagen: molecular structure and fibrillar organization of the chicken alpha 1(V) NH2-terminal domain, a putative regulator of corneal fibrillogenesis

    OpenAIRE

    1993-01-01

    Previous work from our laboratories has demonstrated that: (a) the striated collagen fibrils of the corneal stroma are heterotypic structures composed of type V collagen molecules coassembled along with those of type I collagen, (b) the high content of type V collagen within the corneal collagen fibrils is one factor responsible for the small, uniform fibrillar diameter (25 nm) characteristic of this tissue, (c) the completely processed form of type V collagen found within tissues retains a l...

  20. High-pressure rare earth silicates: Lanthanum silicate with barium phosphate structure, holmium silicate apatite, and lutetium disilicate type X

    International Nuclear Information System (INIS)

    The phase relations of a wide selection of rare earth disilicates have been investigated up to 10 GPa and 1700 deg. C using piston cylinder and multi-anvil equipment. Single-crystal X-ray structures have been obtained for the following high-pressure phases: (1) La2.67(SiO4)2: monoclinic, space group C2/m, Z=2, a=9.419(2), b=5.445(1), c=7.214(1) A, ?=115.71(3)o, R=0.042; disordered Ba3(PO4)2 structure type, with 3xb and 7xb superstructures identified. (2) Ho8.67(SiO4)6(OH)2: hexagonal, P63/m, Z=1, a=9.3221(4), c=6.7347(2) A, R=0.026; silicate hydroxyapatite. (3) Lu2Si2O7: tetragonal, P41212, Z=4, a=6.5620(2), c=11.9535(4) A, R=0.023; type X diorthosilicate structure, and the silicate analogue of tetragonal Er2Ge2O7

  1. Structure of a novel c7-type three-heme cytochrome domain from a multidomain cytochrome c polymer.

    Science.gov (United States)

    Pokkuluri, P Raj; Londer, Yuri Y; Duke, Norma E C; Erickson, Jill; Pessanha, Miguel; Salgueiro, Carlos A; Schiffer, Marianne

    2004-06-01

    The structure of a novel c(7)-type cytochrome domain that has two bishistidine coordinated hemes and one heme with histidine, methionine coordination (where the sixth ligand is a methionine residue) was determined at 1.7 A resolution. This domain is a representative of domains that form three polymers encoded by the Geobacter sulfurreducens genome. Two of these polymers consist of four and one protein of nine c(7)-type domains with a total of 12 and 27 hemes, respectively. Four individual domains (termed A, B, C, and D) from one such multiheme cytochrome c (ORF03300) were cloned and expressed in Escherichia coli. The domain C produced diffraction quality crystals from 2.4 M sodium malonate (pH 7). The structure was solved by MAD method and refined to an R-factor of 19.5% and R-free of 21.8%. Unlike the two c(7) molecules with known structures, one from G. sulfurreducens (PpcA) and one from Desulfuromonas acetoxidans where all three hemes are bishistidine coordinated, this domain contains a heme which is coordinated by a methionine and a histidine residue. As a result, the corresponding heme could have a higher potential than the other two hemes. The apparent midpoint reduction potential, E(app), of domain C is -105 mV, 50 mV higher than that of PpcA. PMID:15133162

  2. A sandwich-type DNA electrochemical biosensor for hairpin-stem-loop structure based on multistep temperature-controlling method

    Directory of Open Access Journals (Sweden)

    Hong GL

    2012-09-01

    Full Text Available Guolin Hong,1,2,* Yinhuan Liu,1,* Wei Chen,3,5 Shaohuang Weng,3,5 Qicai Liu,4 Ailin Liu,3,5 Daoxin Zheng,1 Xinhua Lin,3,51Department of Laboratory Medicine, The Fuzhou Second Affiliated Hospital of Xiamen University, Fuzhou, China; 2Department of Laboratory Medicine, Medical Technology and Engineering College of Fujian Medical University, Fuzhou, China; 3Department of Pharmaceutical Analysis, Pharmacy College of Fujian Medical University, Fuzhou, China; 4Department of Laboratory Medicine, The First Affiliated Hospital of Fujian Medical University, Fuzhou, China; 5Nano Medical Technology Research Institute, Fujian Medical University, Fuzhou, China*Guolin Hong and Yinhuan Liu contributed equally to the present studyAbstract: A highly sensitive and selective method for amplified electrochemical detection for hairpin-stem-loop structured target sequences was developed based on the temperature regulation of DNA hybrids on a sandwich-type electrochemical DNA sensor. Multistep hybridization was applied to promote the hybridization efficiency of each section of sandwich structure. The results showed that both multistep and temperature-controlling hybridization techniques were both especially made to fabricate the sensor for the tendency of internal hybridization of target gene sequences. This strategy provides significantly enhanced hybridization efficiency and sequence specificity of electrochemical detection.Keywords: sandwich-type biosensor, structured target, multistep temperature-controlling, DNA hybridization, tubercle bacillus

  3. Structural studies of P-type ATPase–ligand complexes using an X-ray free-electron laser

    Directory of Open Access Journals (Sweden)

    Maike Bublitz

    2015-07-01

    Full Text Available Membrane proteins are key players in biological systems, mediating signalling events and the specific transport of e.g. ions and metabolites. Consequently, membrane proteins are targeted by a large number of currently approved drugs. Understanding their functions and molecular mechanisms is greatly dependent on structural information, not least on complexes with functionally or medically important ligands. Structure determination, however, is hampered by the difficulty of obtaining well diffracting, macroscopic crystals. Here, the feasibility of X-ray free-electron-laser-based serial femtosecond crystallography (SFX for the structure determination of membrane protein–ligand complexes using microcrystals of various native-source and recombinant P-type ATPase complexes is demonstrated. The data reveal the binding sites of a variety of ligands, including lipids and inhibitors such as the hallmark P-type ATPase inhibitor orthovanadate. By analyzing the resolution dependence of ligand densities and overall model qualities, SFX data quality metrics as well as suitable refinement procedures are discussed. Even at relatively low resolution and multiplicity, the identification of ligands can be demonstrated. This makes SFX a useful tool for ligand screening and thus for unravelling the molecular mechanisms of biologically active proteins.

  4. Structure cristalline de type alluaudite K0.4Na3.6Co(MoO4)3

    Science.gov (United States)

    Nasri, Rawia; Fakhar Bourguiba, Noura; Zid, Mohamed Faouzi

    2015-01-01

    A new triple molybdate, potassium sodium cobalt tris­(molybdate), K0.4Na3.6Co(MoO4)3, was synthesized using solid-state reactions. The Co2+ and one Na+ cation are located at the same general site, each with occupancy 0.5. Another site (site symmetry 2) is occupied by Na+ and K+ cations, with occupancies of 0.597?(7) and 0.402?(6), respectively. The other two Na+ cations and one of the two Mo atoms lie on special positions (site symmetries -1, 2 and 2, respectively). The structure is characterized by M 2O10 (M = Co/Na) dimers, which are linked by MoO4 tetra­hedra, forming infinite layers. The latter are connected firstly by insertion of one type of MoO4 tetra­hedra and secondly by sharing corners with the other type of MoO4 tetra­hedra. This results in an open three-dimensional framework with the cavities occupied by the Na+ and K+ cations. The structure is isotypic with Na3In2As3O12 and Na3In2P3O12. A comparison is made with structures such as K2Co2(MoO4)3 and ?-NaFe2(MoO4)3 and their differences are discussed. PMID:25705436

  5. Photooxidation of benzene-structured compounds: influence of substituent type on degradation kinetic and sum water parameters.

    Science.gov (United States)

    Juretic, Daria; Kusic, Hrvoje; Koprivanac, Natalija; Loncaric Bozic, Ana

    2012-06-01

    The combined influence of substituent type and UV/H(2)O(2) process parameters on the degradation of four aromatic water pollutants was investigated using modified 3(3) full factorial design and response surface methodology. Degradation kinetics was described by the quadratic polynomial model. According to the applied ANOVA, besides pH and [H(2)O(2)], model terms related with the pollutant structure are found to be significant. Different optimal operating conditions and values of observed degradation rate constants were determined for each of the pollutants indicating that the type of substituent influences the overall process effectiveness over structurally defined degradation pathway. Biodegradability (BOD(5)/COD) and toxicity (TU) were evaluated prior to the treatment and at the reference time intervals t(1/2)(P), t(3/4)(P), t(1/4)(OC) and t(1/2)(OC) corresponding to the real time required to reduce the concentration of parent pollutant and organic content for 1/2, 3/4, 1/4 and 1/2 of initial amount. The observed differences are correlated to the structural differences of studied aromatics. PMID:22463859

  6. A formal model for lexical descriptions: Typed feature-structure in the formalism BDéf Un modèle formel de descriptions lexicales: Formalisme BDéf et structures de traits typées

    Directory of Open Access Journals (Sweden)

    Lucie Barque

    2010-01-01

    Full Text Available We propose in this paper a formalization of the BDéf lexicographic definitions proposed by (Altman et Polguère, 2003, in order to carry calculus on them. The information richness of such definitions suggest many calculus that are useful for lexicographic practice as well as for a more general reflection on modelling lexical semantics. Such calculus cannot be realized without a thorough formalization of such definitions that we propose to represent as typed feature structures (Carpenter, 1992. The formalization proposed allow to automatically check for the lexicon consistency, which suggest a new methodology for lexical description based on successive enrichment of the lexical database and the meta data that describe it.

  7. Genome-scale multilocus microsatellite typing of Trypanosoma cruzi discrete typing unit I reveals phylogeographic structure and specific genotypes linked to human infection.

    Science.gov (United States)

    Llewellyn, Martin S; Miles, Michael A; Carrasco, Hernan J; Lewis, Michael D; Yeo, Matthew; Vargas, Jorge; Torrico, Faustino; Diosque, Patricio; Valente, Vera; Valente, Sebastiao A; Gaunt, Michael W

    2009-05-01

    Trypanosoma cruzi is the most important parasitic infection in Latin America and is also genetically highly diverse, with at least six discrete typing units (DTUs) reported: Tc I, IIa, IIb, IIc, IId, and IIe. However, the current six-genotype classification is likely to be a poor reflection of the total genetic diversity present in this undeniably ancient parasite. To determine whether epidemiologically important information is "hidden" at the sub-DTU level, we developed a 48-marker panel of polymorphic microsatellite loci to investigate population structure among 135 samples from across the geographic distribution of TcI. This DTU is the major cause of resurgent human disease in northern South America but also occurs in silvatic triatomine vectors and mammalian reservoir hosts throughout the continent. Based on a total dataset of 12,329 alleles, we demonstrate that silvatic TcI populations are extraordinarily genetically diverse, show spatial structuring on a continental scale, and have undergone recent biogeographic expansion into the southern United States of America. Conversely, the majority of human strains sampled are restricted to two distinct groups characterised by a considerable reduction in genetic diversity with respect to isolates from silvatic sources. In Venezuela, most human isolates showed little identity with known local silvatic strains, despite frequent invasion of the domestic setting by infected adult vectors. Multilocus linkage indices indicate predominantly clonal parasite propagation among all populations. However, excess homozygosity among silvatic strains and raised heterozygosity among domestic populations suggest that some level of genetic recombination cannot be ruled out. The epidemiological significance of these findings is discussed. PMID:19412340

  8. Lack of immunogenicity of ice structuring protein type III HPLC12 preparation administered by the oral route to human volunteers

    DEFF Research Database (Denmark)

    Crevel, R W R; Cooper, K J

    2007-01-01

    Before a novel protein can be used in foods, its potential allergenicity must be assessed. In this study, healthy volunteers consumed ice structuring protein (ISP) Type III preparation or a control material 5 days a week for a total of 8 weeks. General measures of health were recorded during the study, and the immunogenicity of the protein was assessed by monitoring the levels of IgG and IgE antibodies specific for ISP Type III. The participants remained in good health throughout the study and during the 4 week follow-up period. No IgG or IgE antibodies specific for ISP Type III were detected in the blood of the participants. Investigations of immunogenicity in man have not been previously applied in the context of safety evaluation and they do not form part of the regimens proposed for the evaluation of protein allergenicity. Consequently no standardised protocols exist for such studies, nor any background against which to interpret the results. Nevertheless, the absence of an immune response using a protocol which could have been expected to result in a response with a strongly immunogenic protein, confirms the conclusions of earlier published work, and attests to the lack of allergenicity of ISP Type III preparation.

  9. Reliability-Based Earthquake Design of Jacket-Type Offshore Platforms Considering Pile-Soil-Structure Interaction

    Directory of Open Access Journals (Sweden)

    Behrouz Asgarian

    2009-01-01

    Full Text Available There are plenty of uncertainties in environmental condition of ocean and also in platform element capacities. Reliability-based method could consider these uncertainties. A reliability-based earthquake design method was used to determine the earthquake LRFD parameters for two conventional, steel, pile-supported (template-type offshore platforms located in the Persian Gulf. The pile-soil-structure interaction, the buckling and postbuckling behavior of the braces were considered. Two steel platforms were simulated accurately by the finite element program Opensees. Field data were assumed based on past studies. Sensitiveness of reliability-based method was studied. It was found that the geometry of jacket and different types of braces was important in the capacity and the behavior of offshore platforms. Finally the calculated LRFD elements resistance factors for these two platforms were compared with API recommended factors and it was observed that API recommended element resistance factors were more appropriate for SSL 3.

  10. Structures and magnetic properties of p-type Mn:TiO2 dilute magnetic semiconductor thin films

    Science.gov (United States)

    Li, Xinyu; Wu, Shuxiang; Hu, Ping; Xing, Xiangjun; Liu, Yajing; Yu, Yunpeng; Yang, Mei; Lu, Jingquan; Li, Shuwei; Liu, Wen

    2009-08-01

    The behavior of p-type conductivity in Mn-doped TiO2 films grown on LaAlO3 substrates by plasma-assisted molecular beam epitaxy has been investigated. Raman scattering, x-ray photoelectron spectroscopy, and x-ray diffraction studies indicate that the films are single phase, and Mn is successfully doped into the TiO2 matrix. Semiconducting behavior with p-type carriers was confirmed by Hall-effect measurements. The structural and electrical investigations demonstrate that the ferromagnetism observed at room temperature is an intrinsic property of the Mn:TiO2 films, and does not originate from any secondary phase. The magnetic properties of Ti1-xMnxO2 might be related to the formation of acceptor bound magnetic polarons, in which the spins of the holes and manganese are aligned via exchange interaction.

  11. Elastic structural analysis of the pin-type solid breeder blanket first wall

    International Nuclear Information System (INIS)

    A key to the successful design of a fusion blanket is the distribution of the amount of structural material in the first wall and the blanket enclosing structure. The first wall must support dynamic and static mechanical loads and at the same time sustain the thermal gradients and erosion resulting from the plasma heat and particle fluxes. Dynamic and static loads require high flexural rigidity, which is influenced by flow channels designed to cool the high heat flux incident on the first wall. Since the first wall temperature is roughly proportional to its thickness, thermal stresses require a thin first wall. On the other hand, a thick wall is necessary to withstand surface erosion due to particle fluxes. A fesible design must therefore represent an optimal solution satisfying such conflicting requirements

  12. Pareto optimal structures producing resonances of minimal decay under L1-type constraints

    Science.gov (United States)

    Karabash, Illya M.

    2014-07-01

    Resonances optimization is studied under the constraint ??m on the nonnegative function B?L1(0,?) representing the resonator structure. The problem is to design for a given frequency ??R a structure that generates a resonance ? on the line ?+iR with minimal possible decay rate |Im ?|. We generalize the problem replacing B by a nonnegative measure, and show that optimal measures consist of finite number of point masses. This yields non-existence of optimizers for the problem over absolutely continuous measures. We derive restrictions on optimal masses and their positions. This reduces the original infinitely-dimensional problem to optimization over four real parameters. For low frequencies, we explicitly find optimizers. The technique is based on the two-parameter perturbation method and the notion of local boundary point, which is introduced as a generalization of local extrema to vector optimization problems. Special attention is paid to multiple and non-differentiable resonances.

  13. Bifurcation structure of the C-type period-doubling transition

    DEFF Research Database (Denmark)

    Laugesen, Jakob Lund; Mosekilde, Erik

    2012-01-01

    The period-doubling transition to chaos along the edge of an Arnold tongue is known to display unusual organization and scaling behavior (Kuznetsov et al. (2005) [7]). It is also known that forced period-doubling systems may be associated with the appearance of so-called period-doubled tori (Arneodo et al. (1983) [15]). Using the Rössler system as an example, we present a detailed analysis of the bifurcation structure associated with the forcing of a three-dimensional period-doubling system. We explain how this structure is related to the recently discovered phenomenon of multi-layered tori and discuss different bifurcation scenarios that transform a resonance torus into a period-doubled ergodic torus. Similar bifurcation phenomena have recently been observed in a biologically relevant model of kidney blood flow regulation in response to fluctuations in arterial pressure.

  14. Molecular Dynamics Studies on the Structural Stability of Wild-type HORSE PRION PROTEIN

    CERN Document Server

    Zhang, Jiapu

    2011-01-01

    Prion diseases {\\it (e.g. Creutzfeldt-Jakob disease (CJD), variant CJD (vCJD), Gerstmann-Str$\\ddot{\\text{a}}$ussler-Scheinker syndrome (GSS), Fatal Familial Insomnia (FFI) and Kuru in humans, scrapie in sheep, bovine spongiform encephalopathy (BSE or `mad-cow' disease) and chronic wasting disease (CWD) in cattles)} are invariably fatal and highly infectious neurodegenerative diseases affecting humans and animals. However, by now there have not been some effective therapeutic approaches or medications to treat all these prion diseases. Rabbits, dogs, and horses are the only mammalian species reported to be resistant to infection from prion diseases isolated from other species. Recently, the $\\beta$2--$\\alpha$2 loop has been reported to contribute to their protein structural stabilities. The author has found that rabbit prion protein has a strong salt bridge ASP177-ARG163 (like a taut bow string) keeping this loop linked. This paper confirms that this salt bridge also contributes to the structural stability of ...

  15. Molecular Dynamics Studies on the NMR Structures of Rabbit Prion Protein Wild-type and Mutants

    CERN Document Server

    Zhang, Jiapu

    2014-01-01

    Prion diseases are invariably fatal and highly infectious neurodegenerative diseases that affect a wide variety of mammalian species such as sheep, goats, mice, humans, chimpanzees, hamsters, cattle, elks, deers, minks, cats, chicken, pigs, turtles, etc. These neurodegenerative diseases are caused by the conversion from a soluble normal cellular protein into insoluble abnormally folded infectious prions and the conversion is believed to involve conformational change from a predominantly alpha-helical protein to one rich in beta-sheet structure. Such conformational changes may be amenable to study by molecular dynamics techniques. For rabbits, classical studies show they have a low susceptibility to be infected, but in 2012 it was reported that rabbit prion can be generated (though not directly) and the rabbit prion is infectious and transmissible (Proceedings of the National Academy of Sciences USA Volume 109 Issue 13 Pages from 5080 to 5085). This paper studies the molecular structure of rabbit prion protein...

  16. TiNbGa4 - a new structure type of intermetal compounds

    International Nuclear Information System (INIS)

    Crystal structure of TiNbGa4 compound was investigated by the method of powder. It was established that the compound crystallized in rhombic syngony. Distribution of atoms over regular point systems of Pmm2 space group was determined according to the maximal correspondence of experimental and calculated values of reflection intensities. The divergence factor is equal to 0.038 for 43 reflection, observed on diffraction patterns

  17. Structure of the macrozoobenthos as an indicator of different types of pollution in running waters

    OpenAIRE

    Simi? Vladica M.; Simi? Snežana B.

    2002-01-01

    Hydrobiological research on streams with different dominant forms of pollution (anthropogenic eutrophication, organic pollution, toxic pollution, trans-saprobic pollution) in the central part of the Balkan Peninsula (territory of Serbia and Montenegro) indicates that these different forms of pollution can be detected on the basis of structure of the macrozoobenthos community and individual indicator taxa. It is established from the obtained results that the greatest community diversity occurs...

  18. The CNT/BCN/CNT structure (zigzag type) as a molecular switch

    OpenAIRE

    Moghaddam, H Milani

    2010-01-01

    Using a tight-binding model and some well-known approaches and methods based on Green's function theory and Landauer formalism, we numerically investigate the conductance properties and I-V characteristics of zigzag single-walled BCN alloy nanotube in the CNT/BCN/CNT structure, where nanocontacts are considered as zigzag single-walled carbon nanotubes. Our calculations show that any increasing in considerably give rise to the enhancing of the conductance of the system. With ...

  19. Altered lumbar spine structure, biochemistry and biomechanical properties in a canine model of mucopolysaccharidosis type VII

    OpenAIRE

    Smith, Lachlan J.; Martin, John T.; Szczesny, Spencer E.; Ponder, Katherine P; Haskins, Mark E.; Elliott, Dawn M

    2010-01-01

    Mucopolysaccharidosis VII (MPS VII) is a lysosomal storage disorder characterized by a deficiency in ?-glucuronidase activity, leading to systemic accumulation of poorly degraded glycosaminoglycans (GAG). Along with other morbidities, MPS VII is associated with paediatric spinal deformity. The objective of this study was to examine potential associations between abnormal lumbar spine matrix structure and composition in MPS VII, and spine segment and tissue-level mechanical properties, using a...

  20. Structural steel type 14GN2MFA for components of heat exchange equipment

    International Nuclear Information System (INIS)

    Consideration is given to results of investigvation into 14GY2MFA structural stee, designated for manufacture of critical large units of heat exchange equipment. Comparative analysis of properties of this steel and widely used 10GN2MFA steel was conducted. It is shown that 14GN2MFA steel is characterized by higher degree of stability of mechenical properties and deformation ability of heat affected zone under reheating

  1. Structure and function analyses of the purified GPCR human vomeronasal type 1 receptor 1

    OpenAIRE

    Karolina Corin; Philipp Baaske; Sandra Geissler; Wienken, Christoph J.; Stefan Duhr; Dieter Braun; Shuguang Zhang

    2011-01-01

    The vomeronasal system is one of several fine-tuned scent-detecting signaling systems in mammals. However, despite significant efforts, how these receptors detect scent remains an enigma. One reason is the lack of sufficient purified receptors to perform detailed biochemical, biophysical and structural analyses. Here we report the ability to express and purify milligrams of purified, functional human vomeronasal receptor hVN1R1. Circular ...

  2. Magneto structural transition in the DySi CrB- and micro-structural changes in the FeB-type compounds by XRPD and neutron diffraction

    Energy Technology Data Exchange (ETDEWEB)

    Schobinger-Papamantellos, P., E-mail: Schobinger@mat.ethz.c [Laboratory of Crystallography, ETH-Zurich, 8093 Zuerich (Switzerland); Brunelli, M., E-mail: brunelli@ill.e [Institut Laue-Langevin, 156X, 38042 Grenoble Cedex (France); Rodriguez-Carvajal, J., E-mail: jrc@ill.e [Institut Laue-Langevin, 156X, 38042 Grenoble Cedex (France); Buschow, K.H.J. [Van der Waals-Zeeman Institute, University of Amsterdam, NL-1018 XE (Netherlands); Ritter, C. [Institut Laue-Langevin, 156X, 38042 Grenoble Cedex (France); Gramm, F. [Electron Microscopy ETH Zurich (EMEZ), ETH Zurich, CH-8093 Zurich (Switzerland)

    2011-04-15

    We present the magnetic temperature phase diagrams of the CrB- and FeB-type orthorhombic phases of the DySi compound, determined from high-quality powder XRPD and neutron diffraction, as well as the sample microstructure as determined by HRTEM. Both phase diagrams comprise a HT (T{sub c1}, T{sub c2}-T{sub N}) and a LT range (5 K-T{sub c1}, T{sub c2}) separated by a monoclinic phase transition at T{sub c1}=T{sub c2}=23.5 K well below the second-order Neel transition (T{sub N}=40 K). The transition paths are for CrB-type Cmcm (HT) T{sub c1}{yields}C2/m11 (LT), and for FeB Pnma (HT) T{sub c2}{yields}P2{sub 1}/n11 (LT). The transitions are related to non-monotonous changes of the lattice and structural parameters displaying anomalies at T{sub c1}, T{sub c2} and slight volume changes. For the CrB-type the monoclinic angle decreases smoothly from T{sub c1} down to 5 K and the maximum strain experienced by the crystal lattice in the (0 2 1) direction was found at T{sub c1}. In the FeB-type, in addition to the magneto-elastic transition at T{sub c2}=23.5 K, minor anomalies are found at 13.5 K in the temperature dependence of the monoclinic angle and the maximum strain along (0 1 1). Both temperatures mark the sequence of changes in the magnetic domain microstructure observed in FeB: below T{sub 2}=23.5 K the incommensurate HT magnetic phase with q{sub 3{approx}}(01/2 1/7 ) disproportionates into two LT phases q{sub 3{approx}}(01/2 1/(11)) T{sub 2} and q{sub 2{approx}}(01/2 1/6 ) coexisting in the form of domains with portions varying with T going from T{sub 2} down to 13.5 K (q{sub 2} increasing at the cost of q{sub 3}). This behaviour could be related to structural inhomogeneities below the first-order magneto-elastic transition T{sub c2}, if one assumes a broad two phase range, where the HT (Pnma) phase coexists with (P2{sub 1}/n) as a metastable phase at LT in the form of domains with different magnetic behaviour. - Research highlights: > Unusual magneto structural transition in dimorphic DySi (FeB- and CrB-type, T{sub N}=40 K) at T{sub 2}=23.5 K. > Electron microscopy shows no intergrowth domains of the strongly related FeB- and CrB-type phases. > Unusual transition in FeB HT phase q disproportionates below T{sub 2}{yields}2 K into two magnetic phases q{yields}q{sub 1}+q{sub 2}. > X-ray, neutron diffraction relate this phenomenon to a 1st order minor monoclinic distortion at T{sub 2}. > The parent HT and LT FeB structures presumably coexist from T{sub 2}{yields}2 K with distinct magnetic structures.

  3. Minimal changes in rhizobacterial population structure following root colonization by wild type and transgenic biocontrol strains.

    Science.gov (United States)

    Bankhead, Stacey Blouin; Landa, Blanca B; Lutton, Elizabeth; Weller, David M; Gardener, Brian B McSpadden

    2004-08-01

    Pseudomonas fluorescens strains 2-79, Q8r1-96, and a recombinant strain, Z30-97, produce the antibiotics phenazine-1-carboxylic acid (PCA), 2,4-diacetylphloroglucinol (DAPG), or both antibiotics, respectively. Rhizosphere colonization by these strains and subsequent alterations of bacterial community structure were assayed over multiple growth cycles of wheat under controlled conditions. While added to soil at just log 4 cells per gram prior to planting, all four strains subsequently colonized germinating wheat roots to levels in excess of log 6.5 cells per g (f.w.). Strain-specific differences in rhizosphere competence were observed, but these were not generally related to the chromosomal insertion of the phz genes. Multiple differences in bacterial community structure were detected among treatments in each cycle; however, the large majority of changes were not consistently related to the abundance of inoculant strains in the rhizosphere nor the genetic make-up of the inoculant strains. Nonetheless, T-RFLP profiles of amplified 16S eubacterial sequences indicated that, when compared to the untreated samples, inoculation with Z30-97 resulted in several shifts in rhizosphere bacterial community structure previously associated with decreased levels of root disease. PMID:19712423

  4. Novel tailormade Bi4MO4(PO4)2 structural type (M = Mg, Zn).

    Science.gov (United States)

    Endara, Diana; Colmont, Marie; Huvé, Marielle; Tricot, Grégory; Carpentier, Laurent; Mentré, Olivier

    2012-04-16

    In the Bi(2)O(3)-MO-P(2)O(5) ternary system, the commonly observed sizable 1D ribbon-like units have been extended to their 2D infinite end member, leading to the novel tailormade Bi(4)MO(4)(PO(4))(2) compounds. It contains planar [Bi(2)O(2)](2+) derivatives, separated by two slabs of PO(4), which create channels hosting the M(2+) cations (M = Mg, Zn). For both compounds, supercell orderings occur comparatively to the predicted ideal crystal structure (V(Mg) = 2V(ideal) and V(Zn) = 8V(ideal)). In the Mg case a transition into the ideal lattice occurs above 450 °C. In spite of the conceptual assembly of 2D motifs, the final architecture is three-dimensional due to strong interbonds. Thus, our work gives new insights on the possibility for versatile organization of original secondary building units (SBUs) able to self-assemble into predicted structural edifices. Single-crystal and powder XRD versus temperature, high-temperature (31)P NMR, as well as transmission electron microscopy were used for structural characterization. Preliminary electric characterization is also reported. PMID:22449093

  5. Dynamic structural analysis of a head assembly for a large loop-type LMFBR

    International Nuclear Information System (INIS)

    An investigation is presented here on the dynamic structural response of the primary vessel's head closure to slug impact loadings generated from a 1000 MJ source term. The reference reactor considered was designed in a loop configuration. The head structure consisted of a deck and a triple rotatable plug assembly. Two designs were considered for the deck structure: a reference design and an alternate design. The reference deck was designed as a single flat annular plate. For the alternate design, the deck plate was reinforced by adding an extender cylinder with a flange and flanged webs between the deck-plate and cylinder. This investigation showed that the reference design cannot maintain containment integrity when subjected to slug loading generated by a 1000 MJ source term. It was determined that the head deformed excessively. The excessive deformation would, at least, permanently disengage the HCDA seals. More importantly, however, it appears that the entire TRP assembly would be disengaged from the deck creating a large opening for sodium expulsion. With regard to the alternate design, the computations indicated that the deck deformations were acceptable and that no sodium expulsion would occur at the deck-plug juncture

  6. Neutron Dosimetry Study in the Region of the Support Structure of a VVER-1000 Type Reactor

    Science.gov (United States)

    Borodkin, Gennady; Khrennikov, Nikolay; Konheiser, Joerg; Noack, Klaus

    2009-08-01

    The support structure of a reactor pressure vessel experiences high mechanical stresses during reactor operations. In addition, supposed accident conditions and ferritic steel properties result in a low limiting value for the ductile-to-brittle transition temperature and, therefore, a low maximal irradiation load is permitted for this region compared with others. In case of a VVER-1000 reactor, the same applies to weld #5, which is closely above the support structure. The Russian Reactor Operation Rules lay down that profound analyses of the components integrity have to be regularly done if the fluence of neutrons with energies above 0.5 MeV must be expected to accumulate a value greater than 1·1018 n/cm2 during the projected operation time of forty years. Therefore, it was necessary to reliably clarify whether this area of the pressure vessel falls into the category of permanent inspection or not. To this end, precise fluence calculations were carried out. The applied codes and nuclear data sets were verified by special neutron activiation measurements which had been done just in the near neighborhood of the support structure and of weld #5. The calculation results show that in certain subareas of both construction elements the neutron fluence will exceed the limiting value if the reactor is nominally operated during the projected life-time.

  7. Structural and magnetic properties in Heusler-type ferromagnet/antiferromagnet bilayers

    Science.gov (United States)

    Fukatani, N.; Inagaki, K.; Miyawaki, T.; Ueda, K.; Asano, H.

    2013-05-01

    The structure and magnetic properties of Heusler ferromagnet/antiferromagnet (FM/AFM) bilayers were investigated. Structural characterization revealed that Fe2CrSi/Ru2MnGe bilayers were epitaxially grown with an L21 ordered structure when the Ru2MnGe growth temperature was 573 K. The magnetization curve indicates that exchange bias occurs in the Fe2CrSi/Ru2MnGe bilayers at 77 K. The appearance of an exchange-anisotropy field Hex depends on the growth of Ru2MnGe layer, indicating that the exchange bias originates from the epitaxial Fe2CrSi/Ru2MnGe interface. The exchange anisotropy energy Jk of the Fe2CrSi/Ru2MnGe and Co2MnGe/Ru2MnGe bilayer systems appears to follow a Heisenberg-like exchange coupling model. This suggests that the Cr and Mn interface atoms in the FM layers play significant roles in exchange coupling in the Fe2CrSi/Ru2MnGe and Co2MnGe/Ru2MnGe bilayer systems, respectively.

  8. Crystal structures and magnetic properties of the BaAl{sub 4}-type structure derivatives in Gd–Al–Ga system

    Energy Technology Data Exchange (ETDEWEB)

    Belyavina, Nadezhda N., E-mail: nbelyavina@bigmir.net; Babich, Mykola G.; Markiv, Vasyl Ya.; Nakonechna, Olesya I.; Zakharenko, Mykola I.

    2013-11-05

    Highlights: •We study the crystal structure of GdAl{sub x}Ga{sub 4?x} compounds with 8–66 at.% Ga. •Existing range of these compounds is fragmented into seven individual regions. •The effective magnetic moments have been calculated. •The excess magnetic moments are caused by the contribution of the non-4f electrons. -- Abstract: The crystal structures of GdAl{sub x}Ga{sub 4?x?v} compounds (8–66 at.% Ga, x = 3.6–0.70, v = 0–0.12) were studied by the X-ray diffraction methods (both single crystal and powder diffraction ones). Two new types of structure (monoclinic GdAl{sub 3.00}Ga{sub 0.76} and orthorhombic GdAl{sub 2}Ga{sub 2}) were shown to be constructed of two distorted BaAl{sub 4}-like fragments. Reasoning from the peculiarities of crystal structures, the whole existence region of the GdAl{sub x}Ga{sub 4?x?v} compounds is fragmented into seven narrow individual ones (seven compounds). At the temperature range 300–650 K the GdAl{sub x}Ga{sub 4?x?v} alloys were shown to be paramagnets with magnetic moments decreasing from 8.07 to 7.84?{sub B} with Ga-content increasing.

  9. Nanometric solid solutions of the fluorite and perovskite type crystal structures: Synthesis and properties

    Directory of Open Access Journals (Sweden)

    Snežana Boškovi?

    2012-09-01

    Full Text Available In this paper a short review of our results on the synthesis of nanosized CeO2, CaMnO3 and BaCeO3 solid solutions are presented. The nanopowders were prepared by two innovative methods: self propagating room temperature synthesis (SPRT and modified glycine/nitrate procedure (MGNP. Different types of solid solutions with rare earth dopants in concentrations ranging from 0–0.25 mol% were synthesized. The reactions forming solid solutions were studied. In addition, the characteristics of prepared nanopowders, phenomena during sintering and the properties of sintered samples are discussed.

  10. LHD type proton-boron reactor and the control of its peripheral potential structure

    International Nuclear Information System (INIS)

    An advanced Large Helical Device (LHD) type proton-boron reactor, in which the minority protons are heated by ICRF, is proposed. The ratio of the fusion power to the RF input power is evaluated. Numerical computation of particle orbits shows that the ICRF of LHD can accelerate protons in the p-11 B fusion relevant energy. Numerical results also show that the LHD magnetic configuration can confine the high energy 4He well. An active peripheral potential control method and an active 4He ash exhaust scheme are discussed. (author)

  11. The structure of galactic disks: Studying late-type spiral galaxies using SDSS

    OpenAIRE

    Pohlen, M.; Trujillo, I.

    2006-01-01

    Using imaging data from the SDSS survey, we present the g' and r' radial stellar light distribution of a complete sample of ~90 face-on to intermediate inclined, nearby, late-type (Sb-Sdm) spiral galaxies. The surface brightness profiles are reliable (1sigma uncertainty less than 0.2 mag) down to mu=~27magsqarcsec. Only ~10% of all galaxies have a normal/standard purely exponential disk down to our noise limit. The surface brightness distribution of the rest of the galaxie...

  12. Structure of the promoter for chicken alpha 2 type I collagen gene.

    OpenAIRE

    Vogeli, G; Ohkubo, H; Sobel, M E; Yamada, Y.; Pastan, I; DE CROMBRUGGHE, B.

    1981-01-01

    The chicken alpha 2 type I collagen gene is 38 kilobases long and its coding information is subdivided into more than 50 exons. In the current study, we used primer extension and S1 nuclease mapping to determine the sequence of the 5' end of alpha 2 collagen mRNA and to locate the start site for transcription of the alpha 2 collagen gene. The DNA sequence around the start site for transcription shows a typical Goldberg-Hogness sequence, 5' T-A-T-A-A-A-T 3', between -33 and -26 and a 5' G-C-C-...

  13. Structural analysis of the capsid polypeptides of herpes simplex virus types 1 and 2.

    OpenAIRE

    Cohen, G. H.; Ponce Leon, M.; Diggelmann, H.; Lawrence, W. C.; Vernon, S. K.; Eisenberg, R. J.

    1980-01-01

    Capsids of herpes simplex virus (HSV) types 1 and 2 contain seven polypeptides ranging in molecular weight from 154,000 to 12,000 (termed NC-1 through NC-7 in order of descending molecular weight). Antibodies prepared to HSV-1 capsid polypeptides isolated from sodium dodecyl sulfate-polyacrylamide gels reacted in an immunofluorescence assay against HSV-1-infected KB cells. Three of the antibodies (anti-NC-1, anti-NC-2, and anti-NC-3,4) also reacted with HSV-2-infected cells. Tryptic peptide a...

  14. Coronal thermal structure and abundances of supermetal-rich solar-type stars

    Science.gov (United States)

    Brickhouse, Nancy S. (Principal Investigator); Mushotzky, Richard F. (Technical Monitor)

    2005-01-01

    This observation is for grating spectroscopy of Tau Boo, a late-type star with very high metallicity (about twice solar). Despite the extreme condition of high metallicity in the photosphere, the abundance ratios of the corona appear consistent with the general picture of a coronal abundance/activity relation. The target was obtained by XMM-Newton on 24 June 2003 for 71900 sec. The European PI Antonio Maggio is responsible for data reduction. Members of our team presented at the Cool Stars Workshop 13 held in Hamburg, Germany in July 2004 and conferred at that time on the publication of results. This project is complete except for the final publication.

  15. New high-pressure polymorph of In2S3 with defect Th3P4-type structure

    International Nuclear Information System (INIS)

    The high pressure behavior of ?-In2S3 (I41/amd and Z=16) has been studied by in situ synchrotron radiation X-ray diffraction combined with diamond anvil cell up to 71.7 GPa. Three pressure-induced phase transitions are evidenced at ?6.6 GPa, ?11.1 GPa at room temperature and 35.6 GPa after the high-temperature annealing using a portable laser heating system. The new polymorph of In2S3 at 35.6 GPa is assigned to the denser cubic defect Th3P4 structure (I4¯3d and Z=5.333), whose unit-cell parameters are a=7.557(1) Å and V=431.6(2) Å3. The Th3P4-type phase can be stable at least up to 71.7 GPa and cannot be preserved at ambient pressure. The pressure–volume relationship is well described by the second-order Birch–Murnaghan Equation of State, which yields B0=63(3) GPa and B0?=4 (fixed) for the ?-In2S3 phase and B0=87(3) GPa and B0?=4 (fixed) for the defect Th3P4-type phase respectively. - Graphical abstract: The structure and Rietveld refinement of new polymorph the defect Th3P4-type In2S3. This structure was observed at 35.6 GPa after laser heating by X-ray diffraction. Display Omitted - Highlights: Three pressure-induced phase transitions of ?-In2S3 were observed. ?-In2S3 was stable up to 6.6 GPa. The defect Th3P4-type In2S3 was identified at 35.6 GPa after laser heating and was stable up to 71.7 GPa. Elastic properties of ?-In2S3 and Th3P4-type In2S3 are well presented by Birch–Murnaghan EoS

  16. The Effects of Vortex Generator Types on Heat Transfer and Flow Structure in a Rectangular Duct Flows

    OpenAIRE

    Laith J.H; Dr. Sabah Tarik Ahmed; Waheed S. Mohammed

    2008-01-01

    In this numerical study a detailed evaluation of the heat transfer characteristics and flow structure in a laminar and turbulent flow through a rectangular channel containing built-in of different type vortex generator has been a accomplished in a range of Reynolds number between 500 and 100,000.A modified version of ESCEAT code has been used to solve Navier-Stokes and energy equations. The purpose of this paper is to present numerical comparisons in terms of temperature, Nusselt number and f...

  17. Pierce-type dispersion relation for an intense relativistic electron beam interacting with a slow-wave structure

    International Nuclear Information System (INIS)

    A Pierce-type dispersion relation is derived for the interaction of an intense relativistic electron beam with a cylindrical slow-wave structure of arbitrary corrugation depth. It is shown that near a resonance, the Pierce parameter can be expressed in terms of the vacuum dispersion function and the beam current. The dispersion relation is valid in both the low-current (Compton) regime and the high-current (Raman) regime. The dispersion characteristics of the interaction, such as the linear instability growth rate and bandwidth, are analyzed for both regimes

  18. Structural studies of O-polysaccharide isolated from Cronobacter sakazakii Sequence Type 12 from a case of neonatal necrotizing enterocolitis.

    Science.gov (United States)

    Marszewska, Kinga; Czerwicka, Ma?gorzata; Forsythe, Stephen J; Ossowska, Karolina; Dziadziuszko, Halina; Kaczy?ski, Zbigniew

    2015-04-30

    The O-polysaccharide (OPS) of Cronobacter sakazakii NTU 696 (Sequence Type 12) from a case of neonatal necrotizing enterocolitis was isolated from the polysaccharide fraction obtained after lipopolysaccharide (LPS) hydrolysis. Purified OPS was analyzed by NMR spectroscopy ((1)H, COSY, TOCSY, NOESY, HSQC, HSQC-TOCSY and HMBC experiments) and chemical methods. Obtained monosaccharide derivatives analyzed by gas chromatography and gas chromatography-mass spectrometry allowed the identification of six sugar components. Performed experiments enabled to establish a structure of the OPS repeating unit of C. sakazakii NTU 696, as. PMID:25723620

  19. Effect of changing the rare earth cation type on the structure and crystallization behavior of an aluminoborosilicate glass

    OpenAIRE

    Quintas, Arnaud; Caurant, Daniel; Majérus, Odile; Dussossoy, Jean-Luc; Charpentier, Thibault

    2011-01-01

    An aluminoborosilicate glass, containing high amount of rare earth (RE) accordingly to the following composition 50.68 SiO2 - 4.25 Al2O3 - 8.50 B2O3 - 12.19 Na2O - 4.84 CaO - 3.19 ZrO2 - 16.35 RE2O3 (wt.%), is currently under study for the immobilization of nuclear waste solutions. In this work, we wanted to investigate the effect of changing the RE cation type on the glass structure and on its crystallization behavior. For this purpose, a glass series was elaborated in whic...

  20. Enhancing the three-dimensional electronic structure in 1111-type iron arsenide superconductors by H-substitution

    OpenAIRE

    Muraba, Yoshinori; Matsuishi, Satoru; Hosono, Hideo

    2013-01-01

    The 1111-type iron arsenide hydride CaFe1-xCoxAsH was synthesized by high-pressure solid-state reaction, and its electronic structure and superconducting properties were investigated. Bulk superconductivity was observed at x = 0.07-0.26. A maximum superconducting critical temperature Tcmax of 23 K was observed at x = 0.07. These values are in agreement with those of CaFe1-xCoxAsF. The calculated Fermi surface of CaFeAsH has a small three-dimensional 3D hole pocket around the...

  1. Isolation, Structure Determination, and Anti-HIV Evaluation of Tigliane-type Diterpenes and Biflavonoid from Stellera chamaejasme

    OpenAIRE

    Asada, Yoshihisa; Sukemori, Aya; Watanabe, Takashi; Malla, Kuber J.; Yoshikawa, Takafumi; Li, Wei; Kuang, Xinzhu; Koike, Kazuo; Chen, Chin-ho; Akiyama, Toshiyuki; Qian, Keduo; Nakagawa-Goto, Kyoko; Susan L. Morris-Natschke; Lu, Yan; Lee, Kuo-Hsiung

    2013-01-01

    Five novel tigliane-type diterpenes, stelleracins A–E (3–7), a novel flavanone dimer, chamaeflavone A (8), and six known compounds were isolated from roots of Stellera chamaejasme. Their structures were elucidated by extensive spectroscopic analyses. The isolated compounds were evaluated for anti-HIV activity in MT4 cells. New compounds 3–5 showed potent anti-HIV activity (EC90 0.00056–0.0068 ?M) and relatively low or no cytotoxicity (IC50 4.4–17.2 ?M). These new compounds represe...

  2. Structural Basis of the Catalytic Mechanism Operating in Open-Closed Conformers of Lipocalin Type Prostaglandin D Synthase*

    OpenAIRE

    Kumasaka, Takashi; Aritake, Kosuke; Ago, Hideo; Irikura, Daisuke; Tsurumura, Toshiharu; Yamamoto, Masaki; Miyano, Masashi; Urade, Yoshihiro; Hayaishi, Osamu

    2009-01-01

    Lipocalin type prostaglandin D synthase (L-PGDS) is a multifunctional protein acting as a somnogen (PGD2)-producing enzyme, an extracellular transporter of various lipophilic ligands, and an amyloid-? chaperone in human cerebrospinal fluid. In this study, we determined the crystal structures of two different conformers of mouse L-PGDS, one with an open cavity of the ?-barrel and the other with a closed cavity due to the movement of the flexible E-F loop. The upper compartment of the central...

  3. LOCAL STRUCTURE OF THE AgBr1-xIx ROCK-SALT TYPE SOLID-SOLUTION

    OpenAIRE

    Yoshiasa, A.; Koto, K.; Emura, S.; Kanamaru, F.

    1986-01-01

    The local structure of the AgBr1-xIx rock-salt type solid-solution (0?x?0.4) was discussed on the basis of both EXAFS and single crystal X-ray diffraction. The cell dimensions increase linearly with increasing AgI content because of substitution of larger ion I- for Br-. The average distance Ag-(Br,I) determined by X-ray diffraction increase apparently. However the interatomic distances between Ag and Br, which were determined by EXAFS on Ag K- and Br K-edge respectively, decrease with Ag...

  4. The activin receptor-like kinase 1 gene: genomic structure and mutations in hereditary hemorrhagic telangiectasia type 2.

    OpenAIRE

    Berg, J. N.; Gallione, C. J.; Stenzel, T. T.; Johnson, D. W.; Allen, W. P.; Schwartz, C. E.; Jackson, C. E.; Porteous, M. E.; Marchuk, D. A.

    1997-01-01

    The activin receptor-like kinase 1 gene (ALK-1) is the second locus for the autosomal dominant vascular disease hereditary hemorrhagic telangiectasia (HHT). In this paper we present the genomic structure of the ALK-1 gene, a type I serine-threonine kinase receptor expressed predominantly in endothelial cells. The coding region is contained within nine exons, spanning < 15 kb of genomic DNA. All introns follow the GT-AG rule, except for intron 6, which has a TAG/gcaag 5' splice junction. The p...

  5. Hole subband structure and mobility calculations of double p-type d-doped GaAs quantum wells

    Science.gov (United States)

    Rodriguez-Vargas, I.; Gaggero-Sager, L. M.

    2005-08-01

    We calculate the hole subband structure and the mobility of p-type double -doped (DDD) GaAs quantum wells. The study is performed within the lines of the Thomas-Fermi-Dirac (TFD) approximation, varying the interlayer distance between wells (l) and the impurity density (p2D). We also have analysed the many-body effects. For the mobility calculations we propose a phenomenological formulae, which takes into account the most important scattering mechanism at low temperature (ionised impurities). The study shows that many-body effects are important in the level structure calculations. We have found a maximum mobility at 200 Å for an impurity density of 3.0 × 1012 cm-2.

  6. Horizontal loading test by whole model specimen simulating inner concrete structure of PWR type nuclear power plant

    International Nuclear Information System (INIS)

    The Nuclear Power Engineering Test Center has performed a horizontal loading test by a whole model specimen simulating the inner concrete structure of a PWR type nuclear power plant in order to investigate restoring force characteristics of reactor buildings. This report describes the results of examination of applicability to the test results of analysis methods based on elastic theory. The analysis results of elastic stiffness, concrete cracking load, rebar yielding loads and ultimate strength were compared with the test results. According to this examination, it is recognized that even these analysis methods based on elastic theory are comparatively effective for analysis of an inner concrete structure of fairly complex configuration, although there are limits of the scope of applicability. (author)

  7. LaZn12.37?(1, a zinc-deficient variant of the NaZn13 structure type

    Directory of Open Access Journals (Sweden)

    Igor Oshchapovsky

    2011-08-01

    Full Text Available The title compound (lanthanum dodecazinc, LaZn12.37?(1, is confirmed to be a nonstoichiometric (zinc-deficient modification of the NaZn13 structure type, in which one Zn atom (Wyckoff site 8b, site symmetry moverline{3} has a fractional site occupancy of 0.372?(11. The other Zn atom (96i, m and the La atom (8a, 432 are fully occupied. The coordination polyhedra of the Zn atoms are distorted icosahedra, whereas the La atoms are surrounded by 24 Zn atoms, forming pseudo-Frank–Kasper polyhedra. Electronic structure calculations indicate that Zn—Zn bonding is much stronger than La—Zn bonding.

  8. Bacterial eukaryotic type serine-threonine protein kinases: from structural biology to targeted anti-infective drug design.

    Science.gov (United States)

    Danilenko, Valery N; Osolodkin, Dmitry I; Lakatosh, Sergey A; Preobrazhenskaya, Maria N; Shtil, Alexander A

    2011-01-01

    Signaling through protein kinases is an evolutionary conserved, widespread language of biological regulation. The eukaryotic type serine-threonine protein kinases (STPKs) found in normal human microbiote and in pathogenic bacteria play a key role in regulation of microbial survival, virulence and pathogenicity. Therefore, down-regulation of bacterial STPKs emerges as an attractive approach to cure infections. In this review we focused on actinobacterial STPKs to demonstrate that these enzymes can be used for crystal structure studies, modeling of 3D structure, construction of test systems and design of novel chemical libraries of low molecule as weight inhibitors. In particular, the prototypic pharmacological antagonists of Mycobacterium tuberculosis STPKs are perspective for development of a novel generation of drugs to combat the socially important disease. These inhibitors may modulate both actinobacterial and host STPKs and trigger programmed death of pathogenic bacteria. PMID:21513496

  9. Energy spectrum of quantum wells in PbTe/PbEuTe type structures based on photoluminescence data

    CERN Document Server

    Zasavitskij, I I; Abramof, E

    2002-01-01

    The effect of the dimensional quantization and temperature on the energy spectrum of structures with the quantum wells of the PbTe/PbEuTe-type is studied. The calculated spectrum is compared with the data on the photoluminescence spectra, measured at 4.2 and 77.4 K. The energies of the emitting transitions are well described within the frames of the two-zone model with an account of the nonparabolicity, anisotropy and PbTe multivalley structure as well as by the uniaxial deformation, available in the heterostructures. It is established, that by decrease in the E sub g forbidden zone width the dE sub g /dT temperature coefficient in the two-dimensional heterostructure decreases, which is explained by weakening the electron-phonon interaction

  10. Effect of Correlation Structure in Generalized Estimating Equation and Quasi Least Square: An Application in Type 2 Diabetes Patient

    Directory of Open Access Journals (Sweden)

    Dilip C Nath

    2011-07-01

    Full Text Available The Quasi-Least Squares (QLS is useful for different correlation structure with attachment of Generalized Estimating Equation (GEE. The purpose of this work is to compare the regression parameter in the presence of different correlation structure with respect to GEE and QLS method. The comparison of estimated regression parameter has been performed in clinical trial data set; studying the effect of drug treatment (metformin with pioglitazone Vs (gliclazide with pioglitazone in type 2 diabetes patients. In case of QLS, the correlation coefficient of post-parandinal blood sugar (PPBS under tridiagonal correlation is 0.008 while it failed to produce by GEE. It has been found that the combination of metformin with pioglitazone is more effective as compared to the combination of gliclazide with pioglitazone.

  11. Effect of Correlation Structure in Generalized Estimating Equation and Quasi Least Square: An Application in Type 2 Diabetes Patient

    Directory of Open Access Journals (Sweden)

    Dilip C Nath

    2011-08-01

    Full Text Available The Quasi-Least Squares (QLS is useful for different correlation structure with attachment of Generalized Estimating Equation (GEE. The purpose of this work is to compare the regression parameter in the presence of different correlation structure with respect to GEE and QLS method. The comparison of estimated regression parameter has been performed in clinical trial data set; studying the effect of drug treatment (metformin with pioglitazone Vs (gliclazide with pioglitazone in type 2 diabetes patients. In case of QLS, the correlation coefficient of post-parandinal blood sugar (PPBS under tridiagonal correlation is 0.008 while it failed to produce by GEE. It has been found that the combination of metformin with pioglitazone is more effective as compared to the combination of gliclazide with pioglitazone.

  12. Apparition de structures tourbillonnaires de type Görtler dans une cavité parallèl-épipédique ouverte de forme variable

    CERN Document Server

    Faure, Thierry; Lusseyran, François; Pastur, Luc

    2007-01-01

    The interaction between a laminar boundary layer and an open cavity is investigated experimentally for Reynolds numbers between 860 and 32300. Flow visualizations are carried out for different observation directions in order to understand the spatial development of dynamical structures. The study is conducted by changing the cavity length and height and the external flow velocity, and therefore the flow patterns inside the cavity. The issue is to emphasize the three-dimensional development of the flow. In particular, we show that the cavity dynamical structures are not due to secondary shear layer instabilities. Görtler-type vortices are developing inside the cavity for some parameters and their properties are discussed. The existence diagram of these instabilities is also provided.

  13. Enhanced pedestal pressure and parameter-linkages determining edge pedestal structure in JT-60U type I and type II ELMy H-mode

    International Nuclear Information System (INIS)

    Based on the expanded H-mode operational regimes in JT-60U utilizing the improved capability of high triangularity (?) operation, the multiple pellet injection and high power heating including the negative ion based NB (NNB), we have clarified the pedestal parameter-linkages determining the pedestal structure (i.e. 'The pedestal width' increases with ?pi and does not depend on ?p-ped. 'The normalized pressure gradient ?' is almost constant at low ?, while ? ? ?p at high ?). Based on these results, we have enhanced the pedestal pressure of the ELMy H-mode by factors of 2-2.5 at the same plasma current and plasma shape, and extended the high confinement regime to a high density. We have found that the pedestal stored energy Wped increases with the core energy (or ?p-core) at high ? (>0.3-0.4), while Wped is low and almost constant independent of, for example, heating power at low ? (95<4) regime, and demonstrated successful compatibility of the type II ELMs with the pellet injection. Based on a variety of JT-60U experiments, possible linkages among the pedestal and the core parameters has been proposed. (author)

  14. Controlling factors of Tc dome structure in 1111-type iron arsenide superconductors

    Science.gov (United States)

    Matsuishi, Satoru; Maruyama, Takuya; Iimura, Soshi; Hosono, Hideo

    2014-03-01

    We investigated the effects of phosphorus substitution on the shape of the Tc(x ) dome in 1111-type SmFeAs1 -yPyO1 -xHx (0 As3 -) can induce only a chemical pressure effect, i.e., an increase of ? for La substitution of Sm sites. As y increases from 0.0 to 0.5, the single Tc dome gradually splits into two domes, similar to those of LaFeAsO1 -xHx with a Tc valley at x ? 0.16. We found that the Tc valley is located around (x , ?) ? (0.16, 113°) for both of the SmFeAs1 -yPyO1 -xHx and LaFeAsO1 -xHx series, irrespective of changes in the Pn anion and Ln cation species. This result suggests that suppression of Tc leads to the emergence of a Tc valley when both the shape of FeP n4 tetrahedra represented by ? and electron-doping level of x meet the above criterion in 1111-type iron oxypnictide superconductors.

  15. Structure and function of collectins: humoral C-type lectins with collagenous regions

    DEFF Research Database (Denmark)

    Holmskov, Uffe Laurits; Jensenius, Jens Christian

    1993-01-01

    Collectins are a family of C-type lectins with collagenous regions. Five such lectins have now been described: Lung surfactant protein A and D (SP-A and SP-D), and the plasma proteins, conglutinin, mannan-binding protein (MBP), and CL-43. They are composed of trimeric subunits containing a collagenous section and a C-terminal globular carbohydrate-recognizing domain containing the 14 invariant amino acids characteristic of the C-type lectins. The complete molecules of MBP and SP-A are composed of up to six such subunits, while conglutinin, SP-D and CL-43 contain up to four subunits. The collectins bind to carbohydrates on yeast, bacteria and viruses. The collagenous section reacts with the C1q receptor (collectin receptor) found on many cells including phagocytes. One function of these lectins appears to be the enhancement of phagocytosis, i.e. opsonization. One of the collectins, mannan-binding protein, activates the C1r2C1s2 complex of the classical complement pathway independently of C1q. Collectins have been found in several mammalian species and in the chicken. It seems likely that the biological role of the collectins is to participate in the innate immune defense.

  16. Metal binding properties and structure of a type III metallothionein from the metal hyperaccumulator plant Noccaea caerulescens.

    Science.gov (United States)

    Fernandez, Lucia Rubio; Vandenbussche, Guy; Roosens, Nancy; Govaerts, Cédric; Goormaghtigh, Erik; Verbruggen, Nathalie

    2012-09-01

    Metallothioneins (MT) are low molecular weight proteins with cysteine-rich sequences that bind heavy metals with remarkably high affinities. Plant MTs differ from animal ones by a peculiar amino acid sequence organization consisting of two short Cys-rich terminal domains (containing from 4 to 8 Cys each) linked by a Cys free region of about 30 residues. In contrast with the current knowledge on the 3D structure of animal MTs, there is a striking lack of structural data on plant MTs. We have expressed and purified a type III MT from Noccaea caerulescens (previously Thlaspi caerulescens). This protein is able to bind a variety of cations including Cd(2+), Cu(2+), Zn(2+) and Pb(2+), with different stoichiometries as shown by mass spectrometry. The protein displays a complete absence of periodic secondary structures as measured by far-UV circular dichroism, infrared spectroscopy and hydrogen/deuterium exchange kinetics. When attached onto a BIA-ATR biosensor, no significant structural change was observed upon removing the metal ions. PMID:22668884

  17. Characterization of one-electron oxidized copper(II)-salophen-type complexes; effects of electronic and geometrical structures on reactivities.

    Science.gov (United States)

    Asami, Kazutaka; Takashina, Akiko; Kobayashi, Misato; Iwatsuki, Satoshi; Yajima, Tatsuo; Kochem, Amélie; van Gastel, Maurice; Tani, Fumito; Kohzuma, Takamitsu; Thomas, Fabrice; Shimazaki, Yuichi

    2014-02-01

    One-electron oxidized salophen-type complexes, [Cu(salophen)](+) (H2salophen = N,N'-bis(3,5-di-tert-butylsalicylidene)-1,2-diaminobenzene), and its methoxy derivatives, [Cu(MeO-salophen)](+) and [Cu(salophen-(MeO)2)](+) (H2MeO-salophen = N,N'-bis(3-tert-butyl-5-methoxysalicylidene)-1,2-diaminobenzene, H2salophen-(MeO)2 = N,N'-bis(3,5-di-tert-butylsalicylidene)-1,2-diamino-4,5-dimethoxybenzene), have been synthesized and structurally characterized, and their reactivities have been investigated. The solid state structures of the one-electron oxidized forms of these complexes suggested that [Cu(salophen)](+) and [Cu(MeO-salophen)](+) can be assigned to relatively localized Cu(ii)-phenoxyl radical complexes, while [Cu(salophen-(MeO)2)](+) is the diiminobenzene radical complex. On the other hand, [Cu(salophen)](+) in solution showed a different electronic structure from that of the solid sample, the radical electron being delocalized over the whole ?-conjugated ligand. The reaction of these oxidized complexes with benzyl alcohol has been investigated in the presence of a large excess of substrate, which revealed the difference in the kinetic behavior between the complexes. The mechanisms of the oxidation have been discussed on the basis of the electronic and geometrical structures and the reaction kinetics. PMID:24302166

  18. Application of cubane-type structures to hydro-treatment catalysis; Application des structures d'architecture cubane a la catalyse d'hydrotraitement

    Energy Technology Data Exchange (ETDEWEB)

    Marchand, K.

    2003-11-01

    [Mo{sub 3}S{sub 4}(H{sub 2}O){sub 9}]{sup 4+} has been prepared and supported on zeolites H-USY and NaY. Using this cluster as a precursor for HDT catalysts has many advantages: it is cationic, already in a sulfided form, and a promoter such as a second metal M' such as Cu, Ni or Pd can be incorporated to form Mo{sub 3}M'S{sub 4}{sup 4+}. The cubane structure was found unchanged after loading in the case of NaY (EXAFS, XPS) and although TEM showed that Mo was mainly on the outer surface of the zeolite crystals, DRX confirmed that a modification of the counter ion also occurred, and an isotherm was obtained with NaY zeolite. A thermal stability study was led under N{sub 2} and a mixture of H{sub 2}/H{sub 2}S to optimize the pretreatment of the catalysts. Those were subsequently pre-sulfided and tested in toluene hydrogenation and their activities with both types of zeolites turned out to be the same or even better than that of catalysts prepared by the classical route. An application to mixed cubane-type structures is also reported. (author)

  19. A new type of artificial structure to achieve broadband omnidirectional acoustic absorption

    KAUST Repository

    Zheng, L.-Y.

    2013-10-18

    We present a design for a two-dimensional omnidirectional acoustic absorber that can achieve 98.6% absorption of acoustic waves in water, forming an effective acoustic black hole. This artificial black hole consists of an absorptive core coated with layers of periodically distributed polymer cylinders embedded in water. Effective medium theory describes the response of the coating layers to the acoustic waves. The polymer parameters can be adjusted, allowing practical fabrication of the absorber. Since the proposed structure does not rely on resonances, it is applicable to broad bandwidths. The design might be extended to a variety of applications.

  20. A new type of artificial structure to achieve broadband omnidirectional acoustic absorption

    Directory of Open Access Journals (Sweden)

    Li-Yang Zheng

    2013-10-01

    Full Text Available We present a design for a two-dimensional omnidirectional acoustic absorber that can achieve 98.6% absorption of acoustic waves in water, forming an effective acoustic black hole. This artificial black hole consists of an absorptive core coated with layers of periodically distributed polymer cylinders embedded in water. Effective medium theory describes the response of the coating layers to the acoustic waves. The polymer parameters can be adjusted, allowing practical fabrication of the absorber. Since the proposed structure does not rely on resonances, it is applicable to broad bandwidths. The design might be extended to a variety of applications.