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Sample records for nasicon type structure

  1. Hybrid functional study of the NASICON-type Na3V2(PO4)3: crystal and electronic structures, and polaron-Na vacancy complex diffusion.

    Science.gov (United States)

    Bui, Kieu My; Dinh, Van An; Okada, Susumu; Ohno, Takahisa

    2015-11-11

    The crystal and electronic structures, electrochemical properties and diffusion mechanism of NASICON-type Na3V2(PO4)3 have been investigated based on the hybrid density functional Heyd-Scuseria-Ernzerhof (HSE06). A polaron-Na vacancy complex model for revealing the diffusion mechanism is proposed for the first time in the field of Na-ion batteries. The bound polaron is found to favorably form at the first nearest V site to the Na vacancy. Consequently, the movement of the Na vacancy will be accompanied by the polaron. Three preferable diffusion pathways are revealed; these are two intra-layer diffusion pathways and one inter-layer pathway. The activation barriers for the intra-layer and inter-layer pathways are 353 meV and 513 meV, respectively. For further comparison, the generalized gradient approximation with an onsite Coulomb Hubbard U (GGA+U) is also employed. PMID:26509737

  2. Caustic Recycle from Hanford Tank Waste Using Large Area NaSICON Structures (LANS)

    Energy Technology Data Exchange (ETDEWEB)

    Fountain, Matthew S.; Sevigny, Gary J.; Balagopal, S.; Bhavaraju, S.

    2009-03-31

    This report presents the results of a 5-day test of an electrochemical bench-scale apparatus using a proprietary (NAS-GY) material formulation of a (Na) Super Ion Conductor (NaSICON) membrane in a Large Area NaSICON Structures (LANS) configuration. The primary objectives of this work were to assess system performance, membrane seal integrity, and material degradation while removing Na from Group 5 and 6 tank waste from the Hanford Site.

  3. 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: 2.561, year: 2014 http://www.sciencedirect.com/science/journal/01672738/266

  4. Infrared and Raman spectroscopic studies of glasses with NASICON-type chemistry

    Indian Academy of Sciences (India)

    K J Rao; K C Sobha; Sundeep Kumar

    2001-10-01

    Structures of NASICON glasses of the general formula AB2(PO4)3, where A = Li, Na or K and B = Fe, Ga, Ti, V or Nb, have been investigated using vibrational (IR and Raman) spectroscopies. Phosphate species appear to establish an equilibrium via a disproportionation reaction involving a dynamical bond-switching mechanism where both charge and bonds are conserved. B ions in the system acquire different coordinations to oxygens. Alkali ions cause absorptions due to cage vibrations. All the observed spectroscopic features are consistent with speciation involving disproportionation reactions.

  5. A carbon coated NASICON structure material embedded in porous carbon enabling superior sodium storage performance: NaTi2(PO4)3 as an example

    Science.gov (United States)

    Jiang, Yu; Zeng, Linchao; Wang, Jiaqing; Li, Weihan; Pan, Fusen; Yu, Yan

    2015-08-01

    Sodium super ion conductor (NASICON) type structure materials (e.g. Na3V2(PO4)3, NaTi2(PO4)3) have been considered as promising electrode materials for sodium-ion batteries (NIBs). However, the inherent poor electronic conductivity of the NASICON type structure materials owing to their poor electronic conductivity of phosphates leads to poor cyclability and rate capability. Here, we develop a general strategy to achieve high rate capability and long cycle life by preparing ``double carbon coating'' NASICON NaTi2(PO4)3 using a soft-chemical method. The obtained carbon-coated NaTi2(PO4)3 within the porous carbon matrix (denoted as NTP@C@PC) imparts a reversible capability of 103 mA h g-1 at 5 C after 5000 cycles and a rate capability of 64 mA h g-1 at 50 C for sodium storage. The high capacity, stable cyclability and excellent rate capability of the NTP@C@PC are attributed to the advantages of the special structure: the fast Na+/e- transfer in the nanocomposites, large surface area and mesoporous nature of the 3D porous carbon matrix that facilitate the electrolyte to soak in, an intimate interaction between the particles and the carbon matrix. In addition, the 3D porous carbon matrix could effectively accommodate the volume variation during a repeated sodiation/desodiation process.Sodium super ion conductor (NASICON) type structure materials (e.g. Na3V2(PO4)3, NaTi2(PO4)3) have been considered as promising electrode materials for sodium-ion batteries (NIBs). However, the inherent poor electronic conductivity of the NASICON type structure materials owing to their poor electronic conductivity of phosphates leads to poor cyclability and rate capability. Here, we develop a general strategy to achieve high rate capability and long cycle life by preparing ``double carbon coating'' NASICON NaTi2(PO4)3 using a soft-chemical method. The obtained carbon-coated NaTi2(PO4)3 within the porous carbon matrix (denoted as NTP@C@PC) imparts a reversible capability of 103 mA h g-1 at 5 C after 5000 cycles and a rate capability of 64 mA h g-1 at 50 C for sodium storage. The high capacity, stable cyclability and excellent rate capability of the NTP@C@PC are attributed to the advantages of the special structure: the fast Na+/e- transfer in the nanocomposites, large surface area and mesoporous nature of the 3D porous carbon matrix that facilitate the electrolyte to soak in, an intimate interaction between the particles and the carbon matrix. In addition, the 3D porous carbon matrix could effectively accommodate the volume variation during a repeated sodiation/desodiation process. Electronic supplementary information (ESI) available. See DOI: 10.1039/C5NR03978A

  6. 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.

  7. Hydrothermal synthesis, structure and characterization of new NASICON related potassium iron (III) pyrophosphate

    Indian Academy of Sciences (India)

    G S Gopalakrishna; B H Doreswamy; M J Mahesh; M Mahendra; M A Sridhar; J Shashidhara Prasad; K G Ashamanjari

    2005-02-01

    A new potassium iron (III) pyrophosphate was synthesized by hydrothermal technique and characterized by X-ray studies. The compound crystallizes in a monoclinic space group, 21/, with cell parameters, = 7.365(2) Å, = 10.017(2) Å, = 8.214(1) Å, = 106.50(1)° and = 4. The structure has tunnel-type cavities and are congenial for ion transportation through them. The compound exhibits moderate thermal stability.

  8. Hydrothermal synthesis, structural and physico-chemical characterizations of two Nasicon phosphates: M{sub 0.50}{sup II}Ti{sub 2}(PO{sub 4}){sub 3} (M = Mn, Co)

    Energy Technology Data Exchange (ETDEWEB)

    Essehli, Rachid, E-mail: essehli_rachid@yahoo.fr [Laboratory of Mineral Solid and Analytical Chemistry ' LMSAC' , 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 ' LMSAC' , Department of Chemistry, Faculty of Sciences, University Mohamed I, Po. Box 717, 60000 Oujda (Morocco); Benmokhtar, S. [Laboratoire de Chimie des Materiaux Solides (LCMS) Universite HassanII-Mohammedia, Faculte des Sciences Ben M' Sik, Departement de Chimie, Casablanca (Morocco); Fejfarova, Karla; Dusek, Michal [Institute of Physics, Na Slovance 2, 182 21 Praha 8 (Czech Republic)

    2009-07-01

    The family of titanium Nasicon-phosphates of generic formula M{sub 0.5}{sup II}Ti{sub 2}(PO{sub 4}){sub 3} has been revisited using hydrothermal techniques. Two phases have been synthesized: Mn{sub 0.5}{sup II}Ti{sub 2}(PO{sub 4}){sub 3} (MnTiP) and Co{sub 0.5}{sup II}Ti{sub 2}(PO{sub 4}){sub 3} (CoTiP). Single crystal diffraction studies show that they exhibit two different structural types. Mn{sub 0.5}{sup II}Ti{sub 2}(PO{sub 4}){sub 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) A{sup 3} and Z = 6). The Co{sub 0.5}{sup II}Ti{sub 2}(PO{sub 4}){sub 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) A{sup 3} and Z = 6). These two compounds are clearly related to the parent Nasicon-type rhombohedral structure, which can be described using [Ti{sub 2}(PO{sub 4}){sub 3}] framework composed of two [TiO{sub 6}] octahedral interlinked via three [PO{sub 4}] tetrahedra. {sup 31}P 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.

  9. Ion conductivity of nasicon ceramics

    International Nuclear Information System (INIS)

    The Nasiconss,Na1+XZr2SiXP3-XO12 o , X , 3, includes some of the best solid state sodium conductors known today. Compositions in the interval 1.6 , X , 2.6 show conductivities comparable to the best ? double-prime-alumina ceramics. It is well known that the ion conductivity of ?-alumina is strongly dependent on the texture of the ceramic. Here a similar behavior is reported for Nasicon ceramics. Ceramics of the bulk composition Na2.94Zr1.49Si2.20P0.80O10.85 were prepared by a gel method. The final ceramics consist of Nasicon crystals with x = 2.14 and a glass phase. The grain size and texture of the ceramics were controlled by varying the thermal history of the gel based raw materials and the sintering conditions. The room temperature resistivity of the resulting ceramics varies from 3.65*103 ohm cm to 1.23*103 ohm cm. Using the temperature comparison method and estimates of the area of grain boundaries in the ceramics, the resistivity of the Nasicon phase is estimated to be 225 ohm cm at 25 degrees C. B2O3- or Al2O3-doping of the glass bearing Nasicon ceramic lower the room temperature resistivity by a factor 2 to 5. The dopants do not substitute into the Nasicon phase in substantial amounts

  10. 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

  11. 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)

  12. 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 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.

  13. Synthesis and properties of nasicon prepared from different zirconia-based precursors

    Directory of Open Access Journals (Sweden)

    Fuentes, R. O.

    1999-12-01

    Full Text Available This work reports on the synthesis and characterization of NASICON prepared from SiO2, Na3PO4.12H2O and two types of zirconia: pure monoclinic ZrO2 and TZP (Tetragonal Polycrystalline Zirconia, with 3 mol% Y2O3 as raw materials. The classical ceramic method was used in all cases. SEM, XRD and DTA were used to follow the synthesis and sintering process, and impedance spectroscopy (IS was used to study the electrical properties of sintered pellets. Results obtained with different NASICON samples showed a significant role of composition and processing conditions on the electrical properties. Samples based on TZP, sintered at 1210ºC, exhibited densities of about 3.20 g/cm3 (98% of theoretical density of NASICON and ionic conductivities of about 2x10-3 S.cm-1 at room temperature a rather interesting result when compared with data obtained with the material prepared from pure ZrO2.

    Este trabajo trata de la síntesis y caracterización de NASICON preparado a partir de SiO2 , Na3PO4.12H2O y dos tipos de circonia, ZrO2 monoclínica pura y TZP (circonia policristalina tetragonal, con 3 moles% Y2O3 como materia prima. Se emplea el método cerámico clásico en todos los casos. Las técnicas de MEB, DRX y ATD se emplean para seguir la síntesis y el proceso de sinterización. La espectroscopia de impedancia compleja se emplea para estudiar las propiedades eléctricas de las muestras sinterizadas. Los resultados obtenidos con diferentes muestras de NASICON mostraron un papel significativo de la composición y condiciones de procesamiento sobre las propiedades eléctricas. Las muestras basadas en TZP, sinterizadas a 1210ºC, presentan densidades alrededor de 3.20 g/cm3 (98% de la densidad teórica del NASICON y conductividad iónica de 2x 10-3 5.cm-1 a temperatura ambiente, un resultado bastante interesante cuando se compara con datos obtenidos con material preparado de ZrO2 pura.

  14. 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.

  15. Structural and electrochromic properties of Fe2(SO4)3 nanostructures prepared by template assisted method

    Science.gov (United States)

    Sahana M., B.; Chandran, Sudakar; Naik, Ratna; Naik, Vaman

    2010-04-01

    Oxides containing polyanions such as XO4^2- (X = S, Mo, P and W) as lithium insertion hosts are promising cathode materials due to their high thermal stability. However, the larger separation of the transition metal ions can be expected to reduce the electron mobility. As observed in LiFePO4, this can be overcome either by coating the cathode materials with carbon or by decreasing the particle size. We have prepared nanowires of NASICON type structure and platelets of monoclinic Fe2(SO4)3 by template assisted electro deposition. These structures were grown on stainless steel substrates and are characterized by XPS, HRTEM, and XRD analysis. Both NASICON and monoclinic Fe2(SO4)3 structures are very porous and are comprised of nanoparticles leading to a high lithium insertion capacity.

  16. Type-II Matrices and Combinatorial Structures

    OpenAIRE

    Chan, Ada; Godsil, Chris

    2007-01-01

    Type-II matrices are a class of matrices used by Jones in his work on spin models. In this paper we show that type-II matrices arise naturally in connection with some interesting combinatorial and geometric structures.

  17. Polar structures in late-type galaxies

    OpenAIRE

    Moiseev, Alexei

    2014-01-01

    A common point of view is that stable polar structures are mainly present in the E/S0 early-type galaxies lacking dense gas in their host disks. However, nuclear, as well as external polar rings and disks also exist in the late-type hosts, including gas-rich dwarf galaxies. Using the 3D spectroscopic observations of these objects we can derive the rotation properties of the gas components separately in the main and polar planes. The most detailed picture of the gas kinematic...

  18. Synthesis and characterization of a NaSICON series with general formula Na2.8Zr2-ySi1.8-4yP1.2+4yO12 (0=

    International Nuclear Information System (INIS)

    In this work, we present the synthesis and the characterization of ionic conducting ceramics of NaSICON-type (Natrium super ionic conductor). The properties of this ceramic make it suitable for use in electrochemical devices. These solid electrolytes can be used as sensors for application in the manufacturing of potentiometric gas sensors, for the detection of pollutant emissions and for environment control. The family of NaSICON that we studied has as a general formula Na2.8Zr2-ySi1.8-4yP1.2+4yO12 with 0=2.8Zr1.775Si0.9P2.1O12 composition

  19. Structure of a Type IV Secretion System

    OpenAIRE

    Low, Harry H.; Gubellini, Francesca; Rivera-Calzada, Angel; Braun, Nathalie; Connery, Sarah; Dujeancourt, Annick; Lu, Fang; Redzej, Adam; Fronzes, Rémi; Orlova, Elena V.; Waksman, Gabriel

    2014-01-01

    Bacterial type IV secretion (T4S) systems translocate virulence factors into eukaryotic cells1,2, distribute genetic material between bacteria, and have shown potential as a tool for the genetic modification of human cells3. Given the complex choreography of the substrate through the secretion apparatus4, the molecular mechanism of the T4S system has proven difficult to dissect in the absence of structural data for the entire machinery. Here we use electron microscopy (EM) to reconstruct the ...

  20. Crystallostructural features of ion transport in new OD-structures: catapleite Na2ZrSi3O9·2H2O and ilerite Na2ZrSi3O9·3H2O

    International Nuclear Information System (INIS)

    The formation of new OD-structures in the class of alkali MT-compounds (M=Zr, Sc, rare earths, T=Si, P) with disordered Na sublattice is analized. The experimental proof of ion conductivity presence is obtained and a reversible phase transition is registered for the synthetic catapleite analog crystallizing in the hydrothermal system ZrO2-SiO2-NaOH-H2O. Crystallostructural features of phase transitions in catapleite (of the shift type) and Zr- and Sc-NASICON (transitions of the order-disorder type) are considered. Compounds with two-dimensional Na-sublattices are found for the first time among three-dimensional MT-structures with disordered Na-sublattice which permits to use catapleite and ilerite crystals as the object for detail study of ion-transport characteristics anisotropy

  1. Study on lithium/air secondary batteries - Stability of NASICON-type lithium ion conducting glass-ceramics with water

    Energy Technology Data Exchange (ETDEWEB)

    Hasegawa, Satoshi; Imanishi, Nobuyuki; Zhang, Tao; Xie, Jian; Hirano, Atsushi; Takeda, Yasuo; Yamamoto, Osamu [Department of Chemistry, Faculty of Engineering, Mie University, 1577 Kurimamachiya-cho, Tsu, Mie 514-8507 (Japan)

    2009-04-01

    The water stability of the fast lithium ion conducting glass-ceramic electrolyte, Li{sub 1+x+y}Al{sub x}Ti{sub 2-x}Si{sub y}P{sub 3-y}O{sub 12} (LATP), has been examined in distilled water, and aqueous solutions of LiNO{sub 3}, LiCl, LiOH, and HCl. This glass-ceramics are stable in aqueous LiNO{sub 3} and aqueous LiCl, and unstable in aqueous 0.1 M HCl and 1 M LiOH. In distilled water, the electrical conductivity slightly increases as a function of immersion time in water. The Li-Al/Li{sub 3-x}PO{sub 4-y}N{sub y}/LATP/aqueous 1 M LiCl/Pt cell, where lithium phosphors oxynitrides Li{sub 3-x}PO{sub 4-y}N{sub y} (LiPON) are used to protect the direct reaction of Li and LATP, shows a stable open circuit voltage (OCV) of 3.64 V at 25 C, and no cell resistance change for 1 week. Lithium phosphors oxynitride is effectively used as a protective layer to suppress the reaction between the LATP and Li metal. The water-stable Li/LiPON/LATP system can be used in Li/air secondary batteries with the air electrode containing water. (author)

  2. 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

  3. 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.

  4. Types and Functions of Coastal Structures

    OpenAIRE

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

    2005-01-01

    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.

  5. 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.

  6. Prediction of Type A behaviour : a structural equation model

    OpenAIRE

    Marius Pretorius; Gideon Nieman; Jurie van Vuuren; André B. Boshoff; René van Wyk

    2009-01-01

    The predictability of Type A behaviour was measured in a sample of 375 professionals with a shortened version of the Jenkins Activity Survey (JAS). Two structural equation models were constructed with the Type A behaviour achievement sub-scale and global (total) Type A as the predictor variables. The indices showed a reasonable-to-promising fit with the data. Type A achievement was reasonably predicted by service-career orientation, internal locus of control, power self-concept and economic i...

  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. Excitonic fine structure splitting in type-II quantum dots

    OpenAIRE

    K?ápek, Vlastimil; Klenovský, Petr; Šikola, Tomáš

    2015-01-01

    Excitonic fine structure splitting in quantum dots is closely related to the lateral shape of the wave functions. We have studied theoretically the fine structure splitting in InAs quantum dots with a type-II confinement imposed by a GaAsSb capping layer. We show that very small values of the fine structure splitting comparable with the natural linewidth of the excitonic transitions are achievable for realistic quantum dot morphologies despite the structural elongation and t...

  9. Co-linear spin configurations in corundum-type structures

    International Nuclear Information System (INIS)

    The colinear magnetic configurations possible in corundum-type structures (?-Fe2O3; Cr2O3) are solutions of a matrices problem. Their regions of stability are bounded by inequality relationships between exchange integrals. (author)

  10. 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)

  11. Prediction of Type A behaviour: a structural equation model

    Scientific Electronic Library Online (English)

    René, van Wyk; André B., Boshoff; Gideon, Nieman; Jurie, van Vuuren; Marius, Pretorius.

    Full Text Available The predictability of Type A behaviour was measured in a sample of 375 professionals with a shortened version of the Jenkins Activity Survey (JAS). Two structural equation models were constructed with the Type A behaviour achievement sub-scale and global (total) Type A as the predictor variables. Th [...] e indices showed a reasonable-to-promising fit with the data. Type A achievement was reasonably predicted by service-career orientation, internal locus of control, power self-concept and economic innovation. Type A global was also predicted by internal locus of control, power self-concept and the entrepreneurial attitude of achievement and personal control.

  12. Prediction of type A behaviour: A structural equation model

    Directory of Open Access Journals (Sweden)

    René van Wyk

    2009-04-01

    Full Text Available The predictability of Type A behaviour was measured in a sample of 375 professionals with a shortened version of the Jenkins Activity Survey (JAS. Two structural equation models were constructed with the Type A behaviour achievement sub-scale and global (total Type A as the predictor variables. The indices showed a reasonable-to-promising fit with the data. Type A achievement was reasonably predicted by service-career orientation, internal locus of control, power self-concept and economic innovation. Type A global was also predicted by internal locus of control, power self-concept and the entrepreneurial attitude of achievement and personal control.

  13. Sums of correlated exponentials: two types of Gaussian correlation structures

    OpenAIRE

    Klymovskiy, Anton (Klimovsky, Anton)

    2008-01-01

    In this thesis, we study the limiting behaviour of the large sums of strongly correlated exponentials as the number of their summands and the effective dimension of the correlation structure simultaneously tend to infinity. We consider two types of such sums which are generated by two a priori very different Gaussian correlation structures. The first type is a sum of hierarchically correlated random variables which is based on the partition function of Derrida's generalised random energy mode...

  14. 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

  15. Fe-doped ?-Rhombohedral boron: Structural changes at the p-type/n-type transition

    Science.gov (United States)

    Werheit, H.; Filipov, V.; Kuhlmann, U.; Dose, T.; Lundström, T.

    2015-09-01

    n-type ?-rhombohedral boron is e.g. obtained by interstitial doping with Fe atoms exceeding 2.45 at.%. The spectra of Raman- and IR-active phonons have been measured up to the solubility limit of ?4 at.%. Numerous significant discontinuities in the spectra indicate structural changes at the p/n-transition. These might be restricted to specific elements of the structure, as the lattice parameters vary continuously, thus indicating that the overall structure remains largely unchanged.

  16. Structural modal reanalysis for large, simultaneous and multiple type modifications

    Science.gov (United States)

    Jian-jun, He; Xiang-zi, Chen; Bin, Xu

    2015-10-01

    Eigenvalue problem is widely used to investigate the dynamic characteristics of large and complex structure. For finite element models, iterative solvers are needed to precisely calculate eigenvectors and eigenvalues. However, in cases such as large-scale reanalysis studies, or optimization design of huge structure, computational cost can quickly become too time consuming. This paper focus on the structural modal reanalysis for large and multiple modifications (including simultaneous boundary, topology and type modifications), which can greatly affect the eigen-modes of the modified structures. The proposed methods are based on the results from the modal analysis of the original structure, and the stiffness and mass matrix of the modified structures. A highly approximate eigensolution are generated by the proposed method, which is combined the newly added DOF (Degrees of Freedom) condensation, ICMO strategy (Independent and Coupling Mass Orthogonalization) with the Rayleigh-Ritz analysis. The numerical examples show that the proposed method is efficient with high precision even when large and multiple type modifications of the structural topology, boundary and type are made simultaneously.

  17. Type I photosynthetic reaction centres: structure and function.

    OpenAIRE

    Heathcote, Peter; Jones, Michael R; Fyfe, Paul???K.

    2003-01-01

    We review recent advances in the study of the photosystem I reaction centre, following the determination of a spectacular 2.5 A resolution crystal structure for this complex of Synechococcus elongatus. Photosystem I is proving different to type II reaction centres in structure and organization, and the mechanism of transmembrane electron transfer, and is providing insights into the control of function in reaction centres that operate at very low redox potentials. The photosystem I complex of ...

  18. Structure of Adeno-Associated Virus Type 4

    OpenAIRE

    Padron, Eric; Bowman, Valorie; Kaludov, Nikola; Govindasamy, Lakshmanan; Levy, Hazel; Nick, Phillip; McKenna, Robert; Muzyczka, Nicholas; John A. Chiorini; Baker, Timothy S.; Agbandje-McKenna, Mavis

    2005-01-01

    Adeno-associated virus (AAV) is a member of the Parvoviridae, belonging to the Dependovirus genus. Currently, several distinct isolates of AAV are in development for use in human gene therapy applications due to their ability to transduce different target cells. The need to manipulate AAV capsids for specific tissue delivery has generated interest in understanding their capsid structures. The structure of AAV type 4 (AAV4), one of the most antigenically distinct serotypes, was determined to 1...

  19. Structure of mammalian protein geranylgeranyltransferase type-I

    OpenAIRE

    Taylor, Jeffrey S.; Reid, T. Scott; Terry, Kimberly L.; Casey, Patrick J; Beese, Lorena S

    2003-01-01

    Protein geranylgeranyltransferase type-I (GGTase-I), one of two CaaX prenyltransferases, is an essential enzyme in eukaryotes. GGTase-I catalyzes C-terminal lipidation of >100 proteins, including many GTP- binding regulatory proteins. We present the first structural information for mammalian GGTase-I, including a series of substrate and product complexes that delineate the path of the chemical reaction. These structures reveal that all protein prenyltransferases share a common reaction mechan...

  20. Structural inheritance in cast 30KhGNM-type steel

    International Nuclear Information System (INIS)

    Structural inheritance in the cast 30KhGNM-type steel depending on the heating rate and the temperature of preliminary tempering is investigated. When eating the cast steel with a beinite structure at the rate of 1-150 deg/min, the restoration of austenite grain and the following recrystallization due to the phase cold work, are observed. Slow heating from room temperature or preliminary tempering hinder grain restoration during heating. A non-monotonous effect of tempering temperature on the structural inheritance is established which can be connected with the kinetics of decomposition of residual austenite in steel

  1. Harmonic structure of type IIIb and III bursts

    International Nuclear Information System (INIS)

    A decameter solar radio storm of type IIIb and III bursts has been analysed, using single frequency records at frequencies 12.5 and 25.0 MHz. Several kinds of burst associations are classified. As a result it is shown that in double oblique burst-traces of type IIIb+III on the frequency-time plane the type III burst is shifted by an octave above the type IIIb burst at any moment of the IIIb+III pair's lifetime. In particular the harmonic structure of the spectrum is peculiar to the event of type IIIb+III in the initial and the final stages. This property of the pair is clear if the type IIIb and III radiations occur at the fundamental coronal plasma frequency and its harmonic respectively. On the other hand, if it is assumed that a type IIIb burst is the precursor of a type III one, there is no reason why the two bursts should be harmonically related. (Auth.)

  2. Crystal structure of clathrates of Hofmann dma-type

    International Nuclear Information System (INIS)

    Seven new clathrates Cd(DMA)2Ni(CN)4·xG (x=1, G=aniline, 2,3-xylidine, 2,4-xylidine, 2,5-xylidine, 2,6-xylidine, 3,5-xylidine, and x=2, G=2,4,6-trimethylaniline) of Hofmann type are synthesized by amine substitution for dimethylamine (DMA). On the base of x-ray diffraction data it is shown that geometry of guest molecule in cage-like hollow determines the structure of the host and crystal structure of clathrates. Two-dimension metallocomplex of the host of studied clathrates is characterized by elastic folded structure appearing as a result of angular deformation of bond between Cd atoms and host cyanide bridge. Guest molecule orientation is fixed by hydrogen bond. Structural elasticity of the host complex directs to differences in crystal structure of clathrates formed and to considerable variety of incorporated guests

  3. 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.

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

    OpenAIRE

    OOsterloo, T.; Morganti, R.; Sadler, E. M; van der 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...

  5. 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

  6. [Microscopic studies of the structures of different dental floss types].

    Science.gov (United States)

    Dörfer, C; Böök, M; Staehle, H J

    1993-01-01

    26 different dental flosses, made from silk, polyamide (Nylon) or Teflon, were analyzed with respect to their surface structure and their cross-section. Principally, two different types of manufacturing could be distinguished. The dental flosses either consisted of a large number of individual fibers, or a single, falted membrane. Even flosses that were manufactured in the same manner revealed considerable differences. Apart from the chemical composition, the structure of dental flosses is decisive for their use and this is why an exact classification would be desirable. In this study the requirements for classifying dental flosses are provided. PMID:8235532

  7. Magnetic mirror structure for testing shell-type quadrupole coils

    Energy Technology Data Exchange (ETDEWEB)

    Andreev, N.; Barzi, E.; Bossert, R.; Chlachidze, G.; Kashikhin, V.S.; Kashikhin, V.V.; Lamm, M.J.; Nobrega, F.; Novitski, I.; Tartaglia, N.; Turrioni, D.; /Fermilab

    2009-10-01

    This paper presents magnetic and mechanical designs and analyses of the quadrupole mirror structure to test single shell-type quadrupole coils. Several quadrupole coils made of different Nb{sub 3}Sn strands, cable insulation and pole materials were tested using this structure at 4.5 and 1.9 K. The coils were instrumented with voltage taps, spot heaters, temperature sensors and strain gauges to study their mechanical and thermal properties and quench performance. The results of the quadrupole mirror model assembly and test are reported and discussed.

  8. The waveguide structures of the inverted-rib type

    Science.gov (United States)

    Rogozi?ski, R.; Tyszkiewicz, C.; Karasi?ski, P.

    2014-05-01

    This paper presents an analysis of the possibilities of producing waveguide structures of the inverted-rib type. Such structures can be produced on the basis of planar gradient strip waveguides (channel waveguides) produced in a glass substrate by the ion exchange method. The glass surface is then covered with a thin uniform optical layer with a high refractive index. The thickness of this layer is less than the cut off thickness for the used wavelength. The wave propagation is therefore possible in the gradient area only. The homogeneous sensitivity of such waveguides is much greater than in case of single-mode waveguides without a uniform layer. The paper presents the calculations of homogeneous sensitivity for single-mode waveguides of the rib type, the inverted rib waveguides and the gradient waveguides. The use of single-mode inverted rib waveguides in the design of the planar interferometer in the Young configuration was proposed.

  9. Robust Structural Optimization Using Gauss-type Quadrature Formula

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Sang Hoon; Seo, Ki Seog; Chen, Shikui; Chen, Wei [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2009-08-15

    In robust design, the mean and variance of design performance are frequently used to measure the design performance and its robustness under uncertainties. In this paper, we present the Gauss-type quadrature formula as a rigorous method for mean and variance estimation involving arbitrary input distributions and further extend its use to robust design optimization. One dimensional Gauss-type quadrature formula are constructed from the input probability distributions and utilized in the construction of multidimensional quadrature formula such as the tensor product quadrature (TPQ) formula and the univariate dimension reduction (UDR) method. To improve the efficiency of using it for robust design optimization, a semi-analytic design sensitivity analysis with respect to the statistical moments is proposed. The proposed approach is applied to a simple bench mark problems and robust topology optimization of structures considering various types of uncertainty.

  10. Robust structural optimization using Gauss-type quadrature formula

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Sang Hoon; Seo, Ki Seog [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Chen, Shikui; Chen, Wei [Northwestern University, Illinois (United States)

    2009-07-01

    In robust design, the mean and variance of design performance are frequently used to measure the design performance and its robustness under uncertainties. In this paper, we present the Gauss-type quadrature formula as a rigorous method for mean and variance estimation involving arbitrary input distributions and further extend its use to robust design optimization. One dimensional Gauss-type quadrature formula are constructed from the input probability distributions and utilized in the construction of multidimensional quadrature formula such as the Tensor Product Quadrature (TPQ) formula and the Univariate Dimension Reduction (UDR) method. To improve the efficiency of using it for robust design optimization, a semi-analytic design sensitivity analysis with respect to the statistical moments is proposed. The proposed approach is applied to a simple bench mark problems and robust topology optimization of structures considering various types of uncertainty.

  11. Temperature Induced Structural Phase Transitions in Chalcopyrite Type Compound Semiconductors

    International Nuclear Information System (INIS)

    Full text : Multinary chalcogenides like Cu(In,Ga)(S,Se)2 are compound semiconductors suitable for applications in thin film photovoltaics. These compounds crystallize in a tetragonal chalcopyrite type structure, which can be described as a ccp array of chalcogen atoms, with metal atoms occupying one half of the tetrahedral voids. The chalcopyrites Cu(In,Ga)(Se,S)2 undergo a temperature dependent structural phase transition from the chalcopyrite to the sphalerite type structure. For CuInS2 and CuInSe2 it is a sharp orderdisorder phase transition, which occurs within a small temperature range of about 10 K. The character of this phase transition is dominated by an increasing Cu-In anti-site occupancy. On the other hand, in CuGaS2 no temperature dependent structural phase transition occurs. The phase transition in CuGaSe2 is characterized by the co-existence of a tetragonal and a cubic phase. Recently this study was extended to the Cu(In,Ga)S2 and Cu(In,Ga)Se2 mixed crystals. This presentation will give a comparative discussion of the structural phase transition in ternary and quaternary chalcopyrites. The basis for our investigations were in-situ high temperature powder diffraction experiments using synchrotron X-rays and were performed at the European Synchrotron Radiation Facility (ESRF), Grenoble, at the high energy beamline ID15B in the temperature range from room temperature to 1100 degrees Cesium. The data were analyzed in detail by the Rietveld refinement method to determine lattice parameters, the anion position and cation site occupancies. The presentation will give an overview of the structural phase transitions observed in these compound semiconductors. The differences between samples with various In/(In+Ga) ratios (from 1 to 0) will be pointed out, concerning not only the transition temperature, but primarily the character of the phase transition, the order parameter, its critical behaviour and universality

  12. Crystal structures and magnetic properties of iron (III)-based phosphates: Na4NiFe(PO4)3 and Na2Ni2Fe(PO4)3

    International Nuclear Information System (INIS)

    Graphical abstract: A perspective view of the Na2Ni2Fe(PO4)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 Na4NiFe(PO4)3 and Na2Ni2Fe(PO4)3. ? Magnetism behaviours of Na4NiFe(PO4)3 and Na2Ni2Fe(PO4)3. ? Antiferromagnetism interactions. ? Mossbauer spectroscopy. - Abstract: Crystal structures from two new phosphates Na4NiFe(PO4)3 (I) and Na2Ni2Fe(PO4)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, R1 = 0.041, wR2=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, ? = 113.66(4)o, R1 = 0.043, wR2=0.111). The three-dimensional structure of (I) is closely related to the Nasicon structural type, consisting of corner sharing [(Ni/Fe)O6] octahedra and [PO4] tetrahedra forming [NiFe(PO4)3]4+ units which align in chains along the c-axis. The Na+ cations fill up trigonal antiprismatic sites within these chains. The crystal structure of (II) belongs to the alluaudite type. Its open framework results from [Ni2O10] units of edge-sharing [NiO6] octahedra, which alternate with [FeO6] octahedra that form infinite chains. Coordination of these chains yields two distinct tunnels in which site Na+. 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 ?-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 ? 19 kOe, revealed in the hysteresis loop measured at 5 K. This transition is most probably associated with a spin-flop transition.

  13. The Structure of Workaholism and Types of Workaholic

    Directory of Open Access Journals (Sweden)

    Malinowska Diana

    2014-06-01

    Full Text Available The aim of the study presented was to verify empirically a conception of workaholism as a multidimensional syndrome. The study also investigated the notion of ‘functional’ and ‘dysfunctional’ types of workaholic, on the basis of the participants’ cognitive evaluations of their quality of life. The research group comprised Polish managers who had graduated with, or were studying to attain, a Master’s degree in Business Administration. The 137 participants completed a set of questionnaires that were based on five different research tools. Confirmatory factor analysis supported the theory that workaholism has a three-dimensional structure that includes behavioural, cognitive, and affective dimensions. Using cluster analysis, three types of worker were identified, two of which represented types of workaholic with different scores for the dimensions of workaholism and for aspects of quality of life. The research demonstrated that workaholism is a three-dimensional construct. It enabled the integration of different perspectives and also confirmed that dysfunctional and functional types of workaholic exist. Furthermore, this paper provides practical insights about workaholism for practitioners of human resources that can be used in the selection and evaluation of employees.

  14. The internal structure of the Sun and solar type stars

    International Nuclear Information System (INIS)

    Our understanding of the internal structure of the Sun and solar type stars has been undermined by recent observations. In this paper some of the puzzles and possible resolutions are considered; the solar neutrino problem, lithium and beryllium abundance, rotation and calcium emission, variation of the solar constant, solar oscillations and the solar convective zone. The picture that emerges in one of confusion, and so it should be since we have no idea of what is going on inside the Sun and a fortiori of what is going on inside other stars. (Auth.)

  15. Structural Biology of Bacterial Type IV Secretion Systems.

    Science.gov (United States)

    Chandran Darbari, Vidya; Waksman, Gabriel

    2015-01-01

    Type IV secretion systems (T4SSs) are large multisubunit translocons, found in both gram-negative and gram-positive bacteria and in some archaea. These systems transport a diverse array of substrates from DNA and protein-DNA complexes to proteins, and play fundamental roles in both bacterial pathogenesis and bacterial adaptation to the cellular milieu in which bacteria live. This review describes the various biochemical and structural advances made toward understanding the biogenesis, architecture, and function of T4SSs. PMID:26034891

  16. New germanide superconductors with the type-I clathrate type structure

    International Nuclear Information System (INIS)

    Highlights: •We discovered that the new germanide superconductors of A8(Al,Ge)46 (A = Rb, Cs). •The superconducting transition temperature is confirmed at around 3.6 K for A = Rb and 4 K for A = Cs. •The M–H curve at 1.8 K shows that the Rb8(Al,Ge)46 belongs to a type-II superconductor. -- Abstract: We discovered that the new germanide superconductors of A8(Al,Ge)46 (A = Rb, Cs). A8(Al,Ge)46 have the type-I clathrate type structure (cubic, space group: Pm3¯n (No. 223)). The superconducting transition temperature is confirmed at around 3.6 K for Rb8(Al0.4Ge0.6)46 and 4 K for Cs8(Al0.4Ge0.6)46, respectively. The lattice constants of these compounds are estimated to be a = 1.082(6) nm for Rb8(Al0.4Ge0.6)46 and a = 1.087(8) nm for Cs8(Al0.4Ge0.6)46. The M–H curve at 1.8 K shows that the Rb8(Al0.4Ge0.6)46 is categorized to be a conventional type-II superconductor. The superconducting parameters of Rb8(Al0.4Ge0.6)46 are determined using the thermodynamic data and Ginzburg–Landau relations

  17. 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.

  18. New germanide superconductors with the type-I clathrate type structure

    Energy Technology Data Exchange (ETDEWEB)

    Ipponjima, T., E-mail: ipponjima@phys.aoyama.ac.jp [Department of Physics and Mathematics, Aoyama-Gakuin University, 5-10-1 Fuchinobe, Sagamihara-shi, Kanagawa 252-5258 (Japan); Kawashima, K.; Miyazaki, S.; Hyakumura, D. [Department of Physics and Mathematics, Aoyama-Gakuin University, 5-10-1 Fuchinobe, Sagamihara-shi, Kanagawa 252-5258 (Japan); Yoshikawa, M. [IMRA Material Co. Ltd., 2-1 Asahicho, Kariya, Aichi 448-0032 (Japan); Akimitsu, J. [Department of Physics and Mathematics, Aoyama-Gakuin University, 5-10-1 Fuchinobe, Sagamihara-shi, Kanagawa 252-5258 (Japan)

    2013-11-15

    Highlights: •We discovered that the new germanide superconductors of A{sub 8}(Al,Ge){sub 46} (A = Rb, Cs). •The superconducting transition temperature is confirmed at around 3.6 K for A = Rb and 4 K for A = Cs. •The M–H curve at 1.8 K shows that the Rb{sub 8}(Al,Ge){sub 46} belongs to a type-II superconductor. -- Abstract: We discovered that the new germanide superconductors of A{sub 8}(Al,Ge){sub 46} (A = Rb, Cs). A{sub 8}(Al,Ge){sub 46} have the type-I clathrate type structure (cubic, space group: Pm3{sup ¯}n (No. 223)). The superconducting transition temperature is confirmed at around 3.6 K for Rb{sub 8}(Al{sub 0.4}Ge{sub 0.6}){sub 46} and 4 K for Cs{sub 8}(Al{sub 0.4}Ge{sub 0.6}){sub 46}, respectively. The lattice constants of these compounds are estimated to be a = 1.082(6) nm for Rb{sub 8}(Al{sub 0.4}Ge{sub 0.6}){sub 46} and a = 1.087(8) nm for Cs{sub 8}(Al{sub 0.4}Ge{sub 0.6}){sub 46}. The M–H curve at 1.8 K shows that the Rb{sub 8}(Al{sub 0.4}Ge{sub 0.6}){sub 46} is categorized to be a conventional type-II superconductor. The superconducting parameters of Rb{sub 8}(Al{sub 0.4}Ge{sub 0.6}){sub 46} are determined using the thermodynamic data and Ginzburg–Landau relations.

  19. 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...

  20. Structure of the atmosphere of late-type stars

    International Nuclear Information System (INIS)

    A method of calculation of model atmospheres of late-type stars is described. The model atmospheres have been constructed for effective temperature Tsub(e)=2500, 3000, 3500, 4000, 4500 and 5785 K at solar chemical composition and surface gravities log g = 0.0, 1.0, 2.0, 3.0, 4.0 and 5.0 based on LTE and a plane-parallel horizontally homogeneous structure. Opacity due to H, H- and H2- was taken into account. The equation of state includes 10 metals and H2, H2- and H2+ molecules. The results are compared with those published elsewhere. A satisfactory agreement is obtained for Tsub(e) > 3000 K

  1. Electronic structure of p type Delta doped systems

    International Nuclear Information System (INIS)

    We summarize of the results obtained for the electronic structure of quantum wells that consist in an atomic layer doped with impurities of p type. The calculations are made within the frame worth of the wrapper function approach to independent bands and with potentials of Hartree. We study the cases reported experimentally (Be in GaAs and B in Si). We present the levels of energy, the wave functions and the rate of the electronic population between the different subbands, as well as the dependence of these magnitudes with the density of impurities in the layer. The participation of the bans of heavy holes is analysed, light and split-off band in the total electronic population. The effect of the temperature is discussed and we give a possible qualitative explanation of the experimental optical properties. (Author)

  2. Structure of mammalian protein geranylgeranyltransferase type-I.

    Science.gov (United States)

    Taylor, Jeffrey S; Reid, T Scott; Terry, Kimberly L; Casey, Patrick J; Beese, Lorena S

    2003-11-17

    Protein geranylgeranyltransferase type-I (GGTase-I), one of two CaaX prenyltransferases, is an essential enzyme in eukaryotes. GGTase-I catalyzes C-terminal lipidation of >100 proteins, including many GTP- binding regulatory proteins. We present the first structural information for mammalian GGTase-I, including a series of substrate and product complexes that delineate the path of the chemical reaction. These structures reveal that all protein prenyltransferases share a common reaction mechanism and identify specific residues that play a dominant role in determining prenyl group specificity. This hypothesis was confirmed by converting farnesyltransferase (15-C prenyl substrate) into GGTase-I (20-C prenyl substrate) with a single point mutation. GGTase-I discriminates against farnesyl diphosphate (FPP) at the product turnover step through the inability of a 15-C FPP to displace the 20-C prenyl-peptide product. Understanding these key features of specificity is expected to contribute to optimization of anti-cancer and anti-parasite drugs. PMID:14609943

  3. 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...

  4. 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.)

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

    International Nuclear Information System (INIS)

    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.)

  6. 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)

  7. Electronic structure of binary phases with a hexagonal WC type structure

    International Nuclear Information System (INIS)

    Electronic structure and interatomic interactions in known binary metal-nonmetal phases with hexagonal (D3h1 symmetry) structure of WC type are studied by self-consistent full-potential method of muffin-tin orbitals. For investigated compounds of d-metals with 2p-nonmetals (RuB, IrB, WC, WN, TaN, TiO) total and partial densities of state and cohesion energies are obtained. On their base relative chemical stability and some physicochemical properties of phases considered are discussed

  8. 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.

  9. Meta-analyses of structural regional cerebral effects in type 1 and type 2 diabetes.

    Science.gov (United States)

    Moulton, Calum D; Costafreda, Sergi G; Horton, Paul; Ismail, Khalida; Fu, Cynthia H Y

    2015-12-01

    Diabetes is associated with macrovascular and microvascular complications and is a major risk factor for neurological and psychiatric disorders, such as dementia and depression. Type 1 diabetes (T1DM) and type 2 diabetes (T2DM) have distinct etiologies and pathophysiological effects while sharing a common endpoint of persistent hyperglycemia. Neuroimaging studies in T1DM have revealed reductions in numerous regions, including the parahippocampal and occipital regions, while in T2DM there have been numerous reports of hippocampal atrophy. This meta-analysis aimed to identify consistent regional abnormalities in cerebral structures in T1DM and T2DM respectively, and also to examine the impact of potential confounds, including age, depression and vascular risk factors. Neuroimaging studies of both voxel-based morphometry (VBM) data and volumetric data were included. Ten T1DM studies (n?=?613 patients) and 23 T2DM studies (n?=?1364 patients) fulfilled inclusion criteria. The T1DM meta-analysis revealed reduced bilateral thalamus grey matter density in adults. The T2DM meta-analysis revealed reduced global brain volume and regional atrophy in the hippocampi, basal ganglia, and orbitofrontal and occipital lobes. Moreover, hippocampal atrophy in T2DM was not modified by hypertension, although there were more marked reductions in younger patients relative to healthy controls. In conclusion, T1DM and T2DM demonstrated distinct cerebral effects with generalised and specific target areas of grey matter reduction. Thalamic atrophy in T1DM may be a substrate of associated cognitive deficits. In T2DM, global cerebral atrophy may reflect atherosclerotic factors, while hippocampal atrophy was an independent effect providing a potential common neuropathological etiology for the comorbidity of T2DM with dementia and depression. PMID:25563229

  10. 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

  11. 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

  12. 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

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

    DEFF Research Database (Denmark)

    Golestan, Saeed; Fernandez, Francisco Daniel Freijedo; Vidal, Ana; Guerrero, Josep M.; Doval-Gandoy, Jesus

    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....

  14. 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.

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

    International Nuclear Information System (INIS)

    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.

  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. Dowel-type fastener connections in timber structures subjected to short-term loading

    DEFF Research Database (Denmark)

    Lauritzen Jensen, J.

    1994-01-01

    Design of dowel-type fastener connections in framed timber structures usually involves a two-step analysis: determination of the distribution of the sectional forces, and design of the eccentrically loaded connections. This report presents an integrated model for design of framed timber structures with dowel-type fastener connections. A Finite-Element approach has been adopted. An element has been developed for modelling a plane group of dowel-type fasteners, taking due account of the material a...

  18. Electronic structure and physical properties of Ba8Ga16Sn30 clathrates with type-I and type-VIII structure

    International Nuclear Information System (INIS)

    A joint experimental and theoretical investigation is performed for Ba-Sn-Ga type-I and type-VIII clathrates. The type-I sample shows a semiconductor characteristic which is accords with the first principle simulation. The type-I clathrate follows Zintl-like behaviour and the semiconducting gap is about 0.6 eV which is agreement with measurement. For the type-VIII clathrate, the simulation shows that a complicated band structure around Fermi level. For the density of states, a peak appears in the fundamental gap, which corresponds to hybridization of Ba bonding orbitals and Sn(Ga) network. A superconducting transition at TC=4 K is observed, which is close to the TC of Sn. An alternative explanation is superconductivity in type-VIII sample arises from increase of electronic density of states around Fermi level EF in the BCS theoretical frame

  19. Vortex-type elastic structured media and dynamic shielding

    CERN Document Server

    Brun, Michele; Movchan, Alexander B

    2012-01-01

    The paper addresses a novel model of metamaterial structure. A system of spinners has been embedded into a two-dimensional periodic lattice system. The equations of motion of spinners are used to derive the expression for the chiral term in the equations describing the dynamics of the lattice. Dispersion of elastic waves is shown to possess innovative filtering and polarization properties induced by the vortextype nature of the structured media. The related homogenised effective behavior is obtained analytically and it has been implemented to build a shielding cloak around an obstacle. Analytical work is accompanied by numerical illustrations.

  20. 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...

  1. Effect of heat treatment conditions on the structure and mechanical properties of DP-type steel

    OpenAIRE

    J. Adamczyk; A. Grajcar

    2006-01-01

    Purpose: The aim of the paper is to determine the influence of the initial structure and heat treatment conditions on mechanical properties of DP-type steel.Design/methodology/approach: The heat treatment of the low-carbon steel in order to obtain a DP-type structure of desirable ferrite and martensite fractions was realized. In order to investigate the structure light and transmission electron microscopy methods were used. Mechanical properties were determined by means of tensile test.Find...

  2. Ion-conduction mechanisms in NaSICON-type membranes for energy storage and utilization

    Energy Technology Data Exchange (ETDEWEB)

    McDaniel, Anthony H. [Sandia National Laboratories (SNL-CA), Livermore, CA (United States); Sandia National Laboratories, Albuquerque, NM (United States); Ihlefeld, Jon F. [Sandia National Laboratories (SNL-CA), Livermore, CA (United States); Sandia National Laboratories, Albuquerque, NM (United States); Bartelt, Norman Charles [Sandia National Laboratories (SNL-CA), Livermore, CA (United States); Sandia National Laboratories, Albuquerque, NM (United States)

    2015-10-01

    Next generation metal-ion conducting membranes are key to developing energy storage and utilization technologies like batteries and fuel ce lls. Sodium super-ionic conductors (aka NaSICON) are a class of compounds with AM 1 M 2 (PO 4 ) 3 stoichiometry where the choice of "A" and "M" cation varies widely. This report, which de scribes substitutional derivatives of NZP (NaZr 2 P 3 O 12 ), summarizes the accomplishments of a Laboratory D irected Research and Development (LDRD) project to analyze transport mec hanisms using a combination of in situ studies of structure, composition, and bonding, com bined with first principles theory and modeling. We developed an experimental platform and applied methods, such as synchrotron- based X-ray spectroscopies, to probe the electronic structure of compositionally well-controlled NaSICON films while in operation ( i.e ., conducting Na ions exposed to oxygen or water va por atmospheres). First principles theory and modeling were used to interpret the experimental observations and develop an enhanced understanding of atomistic processes that give rise to, and affect, ion conduction.

  3. Type of disturbance and ecological history determine structural stability

    OpenAIRE

    Wurff, A.W.G. van der; Kools, S.A.E.; Boivin, M.E.Y.; P. J. Brink; 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...

  4. 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

  5. Profiling of N-Type Dopants in Silicon Based Structures.

    Czech Academy of Sciences Publication Activity Database

    Hovorka, Miloš; Mika, Filip; Frank, Lud?k; Mikulík, P.

    Brno : ISI AS CR, 2009 - (Pokorná, Z.; Mika, F.), s. 14 ISBN 978-80-254-4535-8. [CJCS’09 - Czech-Japan- China Cooperative Symposium on Nanostructure of Advanced Materials and Nanotechnology /4./. Brno (CZ), 10.08.2009-14.08.2009] R&D Projects: GA ?R GP102/09/P543; GA AV ?R IAA100650803 Institutional research plan: CEZ:AV0Z20650511 Keywords : n-type substrate * SEM * PEEM * doping levels Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering

  6. Understanding the Structural Scaling Relations of Early-Type Galaxies

    CERN Document Server

    Porter, Lauren A; Primack, Joel R; Johansson, Peter H

    2014-01-01

    We use a large suite of hydrodynamical simulations of binary galaxy mergers to construct and calibrate a physical prescription for computing the effective radii and velocity dispersions of spheroids. We implement this prescription within a semi-analytic model embedded in merger trees extracted from the Bolshoi Lambda-CDM N-body simulation, accounting for spheroid growth via major and minor mergers as well as disk instabilities. We find that without disk instabilities, our model does not predict sufficient numbers of intermediate mass early-type galaxies in the local universe. Spheroids also form earlier in models with spheroid growth via disk instabilities. Our model correctly predicts the normalization, slope, and scatter of the low-redshift size-mass and Fundamental Plane relations for early type galaxies. It predicts a degree of curvature in the Faber-Jackson relation that is not seen in local observations, but this could be alleviated if higher mass spheroids have more bottom-heavy initial mass functions....

  7. 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.

  8. Structure of a Kunitz-type potato cathepsin D inhibitor.

    Science.gov (United States)

    Guo, Jingxu; Erskine, Peter T; Coker, Alun R; Wood, Steve P; Cooper, Jonathan B

    2015-12-01

    Potato cathepsin D inhibitor (PDI) is a glycoprotein of 188 amino acids which can inhibit both the aspartic protease cathepsin D and the serine protease trypsin. Here we report the first X-ray structure of PDI at a resolution of 2.1Å showing that PDI adopts a ?-trefoil fold, which is typical of the Kunitz-family protease inhibitors, with the inhibitory loops protruding from the core. Possible reactive-site loops including one involving a unique disulphide and another involving a protruding 310 helix are identified and docking studies indicate the mode of action of this unusual bi-functional inhibitor. PMID:26542926

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

    OpenAIRE

    Nenadovi? Aleksandra

    2010-01-01

    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 ty...

  10. Galactic structure and dynamics with late-type stars

    Science.gov (United States)

    Polak, Allyson Anne

    Stellar populations provide important clues to the evolution of the Milky Way. We report the results of two surveys of late-type stars aimed at understanding the nature (dynamics, chemistries) of the disk and halo Galactic stellar populations. We study the kinematical properties of 303 late-type dwarfs out to ~6 kpc at the North Galactic Pole (NGP) as derived from deep ( V ~22), high precision (.001" yr -1 ) proper motions by Majewski (1992) combined with new deep CCD photometry, which yield photometry parallaxes needed to convert the proper motions to U and V space motions. A clear disk population to Z ~3 kpc can be discerned with a strong asymmetric drift gradient of -46±4 km s -1 kpc -1. Halo dwarfs dominate over the thick disk at Z ~3 kpc. In addition to the strong signal of disk stars, a retrograde halo moving group is identified in the U - V plane that is likely the same as the moving group detected at the NGP by Majewski (1992). We have also obtained medium resolution (2-4 Å) spectra for 749 late K and early M giants at mid-latitudes selected from the 2MASS catalog with the FOBOS system at Fan Mountain Observatory. These spectra provide radial velocities (RVs) at the 5 km s -1 level, spectroscopic [Fe/H] good to [sigma]=0.25 dex, and information on the relative abundances of Mg/Fe and Na/Fe in these stars. The UCAC2 proper motions and RVs yield full stellar space motions. We find ail asymmetric drift for the thin/thick disk of -26±4 kill s -1 kpc -1 , significantly smaller than that found for the M dwarf sample above. We attribute the difference to purity of sample in that M giants are not found in the halo field except in readily identifiable halo substructures. Based on the lack of a vertical gradient in the [[alpha]/Fe]-[Fe/H] patterns and the strong vertical gradient in rotational velocity for both of our surveys, we conclude that our findings support a most likely formation scenario in which the thick disk was formed by the heating of the early disk due to a merger.

  11. Characterisation of proton incorporation in perovskite-type structure

    Energy Technology Data Exchange (ETDEWEB)

    Sala, B.; Willemin, S.; Lacroix, O.; Py, J.P. [AREVA NP, Technical Centre - detached at IEM CC047 Place Eugene Bataillon 34095 Montpellier, (France); Colomban, Ph. [Laboratoire de Dynamique, Interactions et Reactivite, UMR 7075 CNRS-UPMC, 2 rue H. Dunant 94 320 Thiais, (France); Julbe, A. [Institut Europeen des membranes CC047 Place Eugene Bataillon France-34095 Montpellier, (France); Rahmouni, K.; Takenouti, H. [Laboratoire des interfaces et des systemes electrochimiques Case 133, Universite Pierre et Marie Curie, 4 place Jussieu, Paris Cedex 05 (France)

    2006-07-01

    Hydrogen could play an increasingly important role as a future energetic carrier. Produced from water it may become a cost competitive alternative to hydrogen made from hydrocarbons. High temperature electrolysis (HTE) could make important contributions where low cost power is available, particularly if coupled with a nuclear plant providing electricity and heat free of greenhouse gas. HTE using H{sup +} ionic electrolyte may operate around 500 C, thus representing technical and economical interest. According to the literature, satisfactory conductivities could be reached with proton conductor ceramic such as perovskites between 400 to 600 C. The ceramics are generally ABO{sub 3} type and doped by lanthanides. The oxides take protons from water vapor or hydrogen molecules in ambient gas as a result of equilibria with defects in the oxide lattice doped by aliovalent cations. This work is devoted to the study of: 1) Oxygen ion vacancies formation by dopant introduction thank to Raman spectroscopy 2) Proton incorporation by thermogravimetric analysis and Raman spectroscopy 3) Proton mobility by means of preliminary conductivity measurements. (authors)

  12. Characterisation of proton incorporation in perovskite-type structure

    International Nuclear Information System (INIS)

    Hydrogen could play an increasingly important role as a future energetic carrier. Produced from water it may become a cost competitive alternative to hydrogen made from hydrocarbons. High temperature electrolysis (HTE) could make important contributions where low cost power is available, particularly if coupled with a nuclear plant providing electricity and heat free of greenhouse gas. HTE using H+ ionic electrolyte may operate around 500 C, thus representing technical and economical interest. According to the literature, satisfactory conductivities could be reached with proton conductor ceramic such as perovskites between 400 to 600 C. The ceramics are generally ABO3 type and doped by lanthanides. The oxides take protons from water vapor or hydrogen molecules in ambient gas as a result of equilibria with defects in the oxide lattice doped by aliovalent cations. This work is devoted to the study of: 1) Oxygen ion vacancies formation by dopant introduction thank to Raman spectroscopy 2) Proton incorporation by thermogravimetric analysis and Raman spectroscopy 3) Proton mobility by means of preliminary conductivity measurements. (authors)

  13. The structure of the follistatin:activin complex reveals antagonism of both type I and type II receptor binding

    Energy Technology Data Exchange (ETDEWEB)

    Thompson, T.B.; Lerch, T.F.; Cook, R.W.; Woodruff, T.K.; Jardetzky, T.S. (NWU)

    2010-03-08

    TGF-{beta} ligands stimulate diverse cellular differentiation and growth responses by signaling through type I and II receptors. Ligand antagonists, such as follistatin, block signaling and are essential regulators of physiological responses. Here we report the structure of activin A, a TGF-{beta} ligand, bound to the high-affinity antagonist follistatin. Two follistatin molecules encircle activin, neutralizing the ligand by burying one-third of its residues and its receptor binding sites. Previous studies have suggested that type I receptor binding would not be blocked by follistatin, but the crystal structure reveals that the follistatin N-terminal domain has an unexpected fold that mimics a universal type I receptor motif and occupies this receptor binding site. The formation of follistatin:BMP:type I receptor complexes can be explained by the stoichiometric and geometric arrangement of the activin:follistatin complex. The mode of ligand binding by follistatin has important implications for its ability to neutralize homo- and heterodimeric ligands of this growth factor family.

  14. Growth of equilibrium structures built from a large number of distinct component types

    OpenAIRE

    Hedges, Lester O.; Mannige, Ranjan V.; Whitelam, Stephen

    2014-01-01

    We use simple analytic arguments and lattice-based computer simulations to study the growth of structures made from a large number of distinct component types. Components possess 'designed' interactions, chosen to stabilize an equilibrium target structure in which each component type has a defined spatial position, and 'undesigned' interactions that allow components to bind in a compositionally-disordered way. We find that high-fidelity growth of the equilibrium target struc...

  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. Effect of heat treatment conditions on the structure and mechanical properties of DP-type steel

    Directory of Open Access Journals (Sweden)

    J. Adamczyk

    2006-04-01

    Full Text Available Purpose: The aim of the paper is to determine the influence of the initial structure and heat treatment conditions on mechanical properties of DP-type steel.Design/methodology/approach: The heat treatment of the low-carbon steel in order to obtain a DP-type structure of desirable ferrite and martensite fractions was realized. In order to investigate the structure light and transmission electron microscopy methods were used. Mechanical properties were determined by means of tensile test.Findings: It was found that a different initial structure influences essentially the martensite morphology in a final DP-type structure. It can occur as a network, fine fibres or islands in a ferritic matrix of high dislocation density in the vicinity of diffusionless transformation products of austenite. The best mechanical properties (UTS=800MPa, YS0.2=520MPa, TEl=20%, UEl=16% has a steel with the martensite in a form of fine fibres.Research limitations/implications: Continuation of the investigations in the field of using the thermomechanical processing to obtain a DP-type steel is foreseen.Practical implications: The established heat treatment conditions can be useful at manufacturing DP-type sheets of high strength and ductile properties and a good suitability for metalforming operations.Originality/value: The relationship between the initial structure and martensite morphology in DP-type steels was specified.

  17. Type II Heat-labile Enterotoxins: Structure, Function, and Immunomofdulatory Properties

    OpenAIRE

    Hajishengallis, George; Connell, Terry D.

    2012-01-01

    The heat-labile enterotoxins (HLTs) of Escherichia coli and Vibrio cholerae are classified into two major types on the basis of genetic, biochemical, and immunological properties. Type I and Type II HLT have been intensively studied for their exceptionally strong adjuvant activities. Despite general structural similarities, these molecules, in intact or derivative (non-toxic) forms, display notable differences in their mode of immunomodulatory action. The molecular basis of these differences ...

  18. Structure, thermal and electrical properties of layered perovskite type Pr2Ti2O7

    International Nuclear Information System (INIS)

    A2B2O7 type compositions with A = trivalent rare-earth ions and B= tetravalent ions, like Ti4+, Zr4+, Hf4+ and Sn4+, have been of interest due to their interesting crystal chemistry and several technological applications. For Ti4+ as B site cation, the A2B2O7 type rare-earth (Ln) titanates form monoclinic perovskite type structure for Ln = La, Nd and Pr while all others form cubic pyrochlore type structure. The monoclinic perovskite type titanates have been of attraction due to their high Curie temperature ferroelectric and piezoelectric properties. Though such titanates have been of technological importance, their structure and phase transition are still remained obscure in literature. A number of symmetry and unit cell parameters have been proposed for such titanates. But all the structures are closely related and they only differed by the shift the rare-earth ions as well as distortion and tilt of the TiO6 octahedral units. Herein we have reported the structure and properties of monoclinic Pr2Ti2O7. Further total energy calculation using DFT formalism were carried out to compare the energetic of different structures. The structural and electrical properties of Pr2Ti2O7 have also been investigated

  19. 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

  20. 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.

  1. A Higher Order Analysis of the Factor Structure of the Myers-Briggs Type Indicator.

    Science.gov (United States)

    Johnson, William L.; Mauzey, Edward; Johnson, Annabel M.; Murphy, Stanley D.; Zimmerman, Kurt J.

    2001-01-01

    Examines the higher order structure of Form G of the Myers Briggs Type Indicator. A third order component analysis of a sample (N=926) found two higher order components. This higher order analysis contributes to the research literature pertaining to the generalized structure of the personality measure. (Contains 44 references and 1 table.) (GCP)

  2. Dance Class Structure Affects Youth Physical Activity and Sedentary Behavior: A Study of Seven Dance Types

    Science.gov (United States)

    Lopez Castillo, Maria A.; Carlson, Jordan A.; Cain, Kelli L.; Bonilla, Edith A.; Chuang, Emmeline; Elder, John P.; Sallis, James F.

    2015-01-01

    Purpose: The study aims were to determine: (a) how class structure varies by dance type, (b) how moderate-to-vigorous physical activity (MVPA) and sedentary behavior vary by dance class segments, and (c) how class structure relates to total MVPA in dance classes. Method: Participants were 291 boys and girls ages 5 to 18 years old enrolled in 58…

  3. Sc29Fe6 a new structure type of the intermetallic compounds

    International Nuclear Information System (INIS)

    The crystal structure of Sc29Fe6 compound is investigated by the monocrystal method and belongs to a new type (space group Pm3, a=1.4361(2) nm). The structure is refined by 285 independent reflexes up to the divergence factor,R=0.067, with isotropic temperature parameters for all atoms, 140 atoms in the elementary cell of Sc29Fe6 structure are placed in 13 proper point systems. The coordination numbers of Sc atoms are 15, 12, and Fe - 12, 11. The icosahedral coordination of atoms is met more often. Sc29Fe6 structure is similar to Sc57Rh13 structure

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

    OpenAIRE

    Joongu Kang; Changsung Kim; Sanghwa Jung; Hongkoo Yeo

    2012-01-01

    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 le...

  5. An Algorithmic Structuration of a Type System for an Orthogonal Object/Relational Model

    CERN Document Server

    Benabbou, Amel; Amghar, Youssef

    2010-01-01

    Date and Darwen have proposed a theory of types, the latter forms the basis of a detailed presentation of a panoply of simple and complex types. However, this proposal has not been structured in a formal system. Specifically, Date and Darwen haven't indicated the formalism of the type system that corresponds to the type theory established. In this paper, we propose a pseudo-algorithmic and grammatical description of a system of types for Date and Darwen's model. Our type system is supposed take into account null values; for such intention, we introduce a particular type noted #, which expresses one or more occurrences of incomplete information in a database. Our algebraic grammar describes in detail the complete specification of an inheritance model and the subryping relation induced, thus the different definitions of related concepts.

  6. 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.

  7. Distinctive structure in dynamic spectra of type V solar radio bursts

    Energy Technology Data Exchange (ETDEWEB)

    Bakunin, L.M.; Markeev, A.K.; Fomichev, V.V.; Chertok, I.M.

    1979-05-01

    Observations of type V solar radio bursts obtained with a 45--90 MHz radio spectrograph at the Institute of Terrestrial Magnetism are discussed. The dynamic spectra of type V events are highly diversified and complex. Categories of bursts are discriminated, depending on the behavior of the radiation at the leading and trailing edges. Various types of fine structure are encountered in the dynamic spectra of many bursts. An analysis is made of type V bursts that distinctly exhibit radio emission at the frequencies of the fundamental and the second harmonic.

  8. 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.

  9. 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.

  10. 1H and 15N NMR resonance assignments and secondary structure of titin type I domains

    International Nuclear Information System (INIS)

    Titin/connect in is a giant muscle protein with a highly modular architecture consisting of multiple repeats of two sequence motifs, named type I and type II. Type I modules have been suggested to be intracellular members of the fibronectin type III (Fn3) domain family. Along the titin sequence they are exclusively present in the region of the molecule located in the sarcomere A-band. This region has been shown to interact with myosin and C-protein. One of the most noticeable features of type I modules is that they are particularly rich in semiconserved prolines, since these residues account for about 8% of their sequence. We have determined the secondary structure of a representative type I domain (A71) by 15N and 1HNMR. We show that the type I domains of titin have the Fn3 fold as proposed, consisting of a three- and a four-stranded ?-sheet. When the two sheets are placed on top of each other to form the ?-sandwich characteristic of the Fn3 fold, 8 out of 10 prolines are found on the same side of the molecule and form an exposed hydrophobic patch. This suggests that the semiconserved prolines might be relevant for the function of type I modules, providing a surface for binding to other A-band proteins. The secondary structure of A71 was structurally aligned to other extracellular Fn3 modules of known 3D structure. The alignment shows that titin type I modules have closest similarity to the first Fn3 domain of Drosophila neuroglian

  11. X-ray structure of a soluble Rieske-type ferredoxin from Mus musculus

    International Nuclear Information System (INIS)

    The X-ray crystal structure of a soluble Rieske ferredoxin from M. musculus was solved at 2.07 Å resolution, revealing an iron–sulfur cluster-binding domain with similar architecture to the Rieske-type domains of bacterial aromatic dioxygenases. The ferredoxin was also shown to be capable of accepting electrons from both eukaryotic and prokaryotic oxidoreductases. The 2.07 Å resolution X-ray crystal structure of a soluble Rieske-type ferredoxin from Mus musculus encoded by the gene Mm.266515 is reported. Although they are present as covalent domains in eukaryotic membrane oxidase complexes, soluble Rieske-type ferredoxins have not previously been observed in eukaryotes. The overall structure of the mouse Rieske-type ferredoxin is typical of this class of iron–sulfur proteins and consists of a larger partial ?-barrel domain and a smaller domain containing Cys57, His59, Cys80 and His83 that binds the [2Fe–2S] cluster. The S atoms of the cluster are hydrogen-bonded by six backbone amide N atoms in a pattern typical of membrane-bound high-potential eukaryotic respiratory Rieske ferredoxins. However, phylogenetic analysis suggested that the mouse Rieske-type ferredoxin was more closely related to bacterial Rieske-type ferredoxins. Correspondingly, the structure revealed an extended loop most similar to that seen in Rieske-type ferredoxin subunits of bacterial aromatic dioxygenases, including the positioning of an aromatic side chain (Tyr85) between this loop and the [2Fe–2S] cluster. The mouse Rieske-type ferredoxin was shown to be capable of accepting electrons from both eukaryotic and prokaryotic oxidoreductases, although it was unable to serve as an electron donor for a bacterial monooxygenase complex. The human homolog of mouse Rieske-type ferredoxin was also cloned and purified. It behaved identically to mouse Rieske-type ferredoxin in all biochemical characterizations but did not crystallize. Based on its high sequence identity, the structure of the human homolog is likely to be modeled well by the mouse Rieske-type ferredoxin structure

  12. Structural Safety Analysis Report of Type IP-2 Radioactive Waste transport Package

    International Nuclear Information System (INIS)

    We carried out structural safety evaluation for the two kinds of type IP-2 package to transport safely radioactive waste drum with using the different thickness steel shell as a shielding material, which is classified as LSA(Low Specific Activity)-II, LSA-III and SCO(Surface Contaminated Object)-II in accordance with IAEA Safety Standard Series No. TS-R-1, Korea Most Act. 2001-23 and US 10 CFR Part 71. The structural analyses of free drop condition and stacking condition under the normal transport conditions were carried out for the type IP-2 radioactive waste transport packages. The drop tests were conducted for two kinds of a transport package. The type IP-2 radioactive waste transport packages were maintained the structural integrities

  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. Crystal structure of a synthetic tin-selenium representative of the cylindrite structure type.

    Czech Academy of Sciences Publication Activity Database

    Makovicky, E.; Pet?í?ek, Václav; Dušek, Michal; Topa, D.

    2008-01-01

    Ro?. 93, 11-12 (2008), s. 1787-1798. ISSN 0003-004X R&D Projects: GA ?R GA202/06/0757 Institutional research plan: CEZ:AV0Z10100521 Keywords : cylindrite * tin- antimony -iron selenide * non-commensurate layer structure * layer-misfit structure * interlayer match Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.962, year: 2008

  15. Allelic diversity and population structure of Bacillus sphaericus as revealed by multilocus sequence typing.

    Science.gov (United States)

    Ge, Yong; Hu, Xiaomin; Zheng, Dasheng; Wu, Yiming; Yuan, Zhiming

    2011-08-01

    The genetic diversity of 35 Bacillus sphaericus strains was analyzed by a newly developed multilocus sequence typing (MLST) scheme, toxin gene pool survey, and mosquito bioassay. The results demonstrated that strains assigned to the same sequence type (ST) had the same occurrence of toxin genes. Further sequence analysis revealed that toxic strains presented a nearly clonal population structure, whereas nontoxic strains had a high level of heterogeneity and were significantly distinct from toxic strains. PMID:21685170

  16. Allelic Diversity and Population Structure of Bacillus sphaericus as Revealed by Multilocus Sequence Typing ? †

    OpenAIRE

    Ge, Yong; Hu, Xiaomin; Zheng, Dasheng; Wu, Yiming; Yuan, Zhiming

    2011-01-01

    The genetic diversity of 35 Bacillus sphaericus strains was analyzed by a newly developed multilocus sequence typing (MLST) scheme, toxin gene pool survey, and mosquito bioassay. The results demonstrated that strains assigned to the same sequence type (ST) had the same occurrence of toxin genes. Further sequence analysis revealed that toxic strains presented a nearly clonal population structure, whereas nontoxic strains had a high level of heterogeneity and were significantly distinct from to...

  17. BaAl4-type derivative structure in superconducting La-Pd-Ge system

    International Nuclear Information System (INIS)

    There are many ternary intermetallic compounds with BaAl4-type and its derivative structures. LaPd2Ge2 is already known as one of the BaAl4-type superconductors with Tc of 1.12 K. We have synthesized a new intermetallic compound La3Pd4Ge4 with higher Tc of 2.75 K than that of LaPd2Ge2, which had the structure with the insertion of the AlB2-type layer in LaPd2Ge2. A detailed crystal structure analysis of La3Pd4Ge4 was carried out by neutron powder diffraction because it is useful to the analysis of small interplanar spacing. The neutron diffraction study indicates that La3Pd4Ge4 has U3Ni4Si4-type structure with a lower symmetry than that of LaPd2Ge2, and the typical interatomic distances of La3Pd4Ge4 are shorter than those of LaPd2Ge2. The coordination of Pd to three Ge in the AlB2-type layer of La3Pd4Ge4 is characteristic, which is not stabilized in other lanthanide-substituted intermetallics Ln3Pd4Ge4 (Ln = Y, Gd-Yb)

  18. Crystal Structure of the Hexachlorocyclohexane Dehydrochlorinase (LinA-Type2): Mutational Analysis, Thermostability and Enantioselectivity

    OpenAIRE

    Macwan, Ankit S.; Kukshal, Vandna; Srivastava, Nidhi; Javed, Saleem; Kumar, Ashwani; Ramachandran, Ravishankar

    2012-01-01

    Hexachlorocyclohexane dehydrochlorinase (LinA) mediates dehydrochlorination of ?-HCH to 1, 3, 4, 6-tetrachloro-1,4-cyclohexadiene that constitutes first step of the aerobic degradation pathway. We report the 3.5 Å crystal structure of a thermostable LinA-type2 protein, obtained from a soil metagenome, in the hexagonal space group P6322 with unit cell parameters a?=?b?=?162.5, c?=?186.3 Å, respectively. The structure was solved by molecular replacement using the co-ordinates of LinA-type1 that...

  19. 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.

  20. Universal Properties of Type IIB and F-theory Flux Compactifications at Large Complex Structure

    CERN Document Server

    Marsh, M C David

    2015-01-01

    We consider flux compactifications of type IIB string theory and F-theory in which the respective superpotentials at large complex structure are dominated by cubic or quartic terms in the complex structure moduli. In this limit, the low-energy effective theory for the complex structure and axio-dilaton sector exhibits universal properties that are insensitive to the details of the compactification manifold or the flux configuration. We show that there are no vacua in this region and the spectrum of the Hessian matrix is highly peaked and consists only of three distinct eigenvalues ($0$, $2m_{3/2}^2$ and $8m_{3/2}^2$), independently of the number of moduli. We briefly comment on how the inclusion of K\\"ahler moduli affect these findings. Our results generalise those of Brodie & Marsh [1], in which these universal properties were found in a subspace of the large complex structure limit of type IIB compactifications.

  1. Prediction of clathrate structure type and guest position by molecular mechanics.

    Science.gov (United States)

    Fleischer, Everly B; Janda, Kenneth C

    2013-05-16

    The clathrate hydrates occur in various types in which the number, size, and shape of the various cages differ. Usually the clathrate type of a specific guest is predicted by the size and shape of the molecular guest. We have developed a methodology to determine the clathrate type employing molecular mechanics with the MMFF force field employing a strategy to calculate the energy of formation of the clathrate from the sum of the guest/cage energies. The clathrate type with the most negative (most stable) energy of formation would be the type predicted (we mainly focused on type I, type II, or bromine type). This strategy allows for a calculation to predict the clathrate type for any cage guest in a few minutes on a laptop computer. It proved successful in predicting the clathrate structure for 46 out of 47 guest molecules. The molecular mechanics calculations also provide a prediction of the guest position within the cage and clathrate structure. These predictions are generally consistent with the X-ray and neutron diffraction studies. By supplementing the diffraction study with molecular mechanics, we gain a more detailed insight regarding the details of the structure. We have also compared MM calculations to studies of the multiple occupancy of the cages. Finally, we present a density functional calculation that demonstrates that the inside of the clathrates cages have a relatively uniform and low electrostatic potential in comparison with the outside oxygen and hydrogen atoms. This implies that van der Waals forces will usually be dominant in the guest-cage interactions. PMID:23600658

  2. Frobenius type and CV-structures for Donaldson-Thomas theory and a convergence property

    CERN Document Server

    Barbieri, Anna

    2015-01-01

    We rephrase some well-known results in Donaldson-Thomas theory in terms of (formal families of) Frobenius type and CV-structures on a vector bundle in the sense of Hertling. We study these structures in an abstract setting, and prove a convergence result which is relevant to the case of triangulated categories. An application to physical field theory is also briefly discussed.

  3. Insect-inspired wing actuation structures based on ring-type resonators:

    OpenAIRE

    Bolsman, C.T.; Goosen, J.F.L.; Keulen, F.

    2008-01-01

    In this paper, we illustrate and study the opportunities of resonant ring type structures as wing actuation mechanisms for a flapping wing Micro Air Vehicle (MAV). Various design alternatives are presented and studied based on computational and physical models. Insects provide an excellent source of inspiration for the development of the wing actuation mechanisms for flapping wing MAVs. The insect thorax is a structure which in essence provides a mechanism to couple the wing muscles to the...

  4. Prodrome of Paranoid Schizophrenia with Episodic Type of Course and Schizoaffective Structure of Manifest Episode

    OpenAIRE

    Alexander S. Bobrov; Marina Yu. Rozhkova; Nina Yu. Rozhkova

    2014-01-01

    Prodrome of paranoid schizophrenia with the episodic type of course (F20.1 and F20.2 according to ICD-10) and the schizoaffective structure of the episode was retrospectively studied. The pronounced and persistent affect, in particular depression in conjunction with hallucinations and/or delusions throughout the whole episode, served as the basis for an episode qualification as the schizoaffective structure. Diagnosis of schizophrenia was confirmed by the extremely low socio-demographic indic...

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

    DEFF Research Database (Denmark)

    Yan, Ning; Naulin, Volker; Xu, G.; Xiong, H.; Wang, H.; Jiang, M.; Liu, P.; Wang, L.; Liu, S.; Zhang, W.; Shao, L.; Wan, B.

    2013-01-01

    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 obser...

  6. Predicting ?-turns and their types using predicted backbone dihedral angles and secondary structures

    OpenAIRE

    Hirst Jonathan D; Kountouris Petros

    2010-01-01

    Abstract Background ?-turns are secondary structure elements usually classified as coil. Their prediction is important, because of their role in protein folding and their frequent occurrence in protein chains. Results We have developed a novel method that predicts ?-turns and their types using information from multiple sequence alignments, predicted secondary structures and, for the first time, predicted dihedral angles. Our method uses support vector machines, a supervised classification tec...

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

    OpenAIRE

    Eisenberg, R.J.; Ponce De 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...

  8. Study of interfaces chemistry in type-II GaSb/InAs superlattice structures

    International Nuclear Information System (INIS)

    There is a considerable interest in type-II GaSb/InAs superlattice system due to several modern applications including infrared detectors. In these studies X-ray photoelectron spectroscopy (XPS) and spectroscopic ellipsometry (SE) have been used for extensive characterization of the surface and interface of GaSb/InAs superlattice. Application of XPS and SE techniques provides precise information from topmost layers of structure and allows excluding presence of GaAs-type interfaces in GaSb/InAs superlattices. It means that Sb-for-As anion exchange does not exist during the molecular beam epitaxial growth of superlattice structures. Simultaneously, these results indicate that InSb-type or GaInSb-type interfaces have been detected in the structures studied. - Highlights: ? The complementary study of InAs/GaSb superlattice interfaces has been proposed. ? InSb and GaInSb interfaces in InAs/GaSb superlattices have been shown. ? The presence of GaAs-type interface in InAs/GaSb superlattices was excluded. ? Sb-for-As exchange during InAs/GaSb superlattice epitaxial growth does not exist.

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

    OpenAIRE

    Grosso, Alejandro; Turull Torres, José María

    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.

  10. Bilingual Children's Acquisition of English Verb Morphology: Effects of Language Exposure, Structure Complexity, and Task Type

    Science.gov (United States)

    Paradis, Johanne

    2010-01-01

    This study investigated whether bilingual-monolingual differences would be apparent in school-age children's use and knowledge of English verb morphology and whether differences would be influenced by amount of exposure to English, complexity of the morphological structure, or the type of task given. French-English bilinguals (mean age = 6;10)…

  11. The Robinson-Trautman Type III Prolongation Structure Contains K$_2$

    OpenAIRE

    Finley, III, J. D.

    1995-01-01

    The minimal prolongation structure for the Robinson-Trautman equations of Petrov type III is shown to always include the infinite-dimensional, contragredient algebra, K$_2$, which is of infinite growth. Knowledge of faithful representations of this algebra would allow the determination of B\\"acklund transformations to evolve new solutions.

  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. 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

  14. 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.

  15. Analysis of waves in the plasma guided by a periodical vane-type slow wave structure

    International Nuclear Information System (INIS)

    In this study, the dispersion relation has been derived to characterize the propagation of the waves in the plasma guided by a periodical vane-type slow wave structure. The plasma is confined by a quartz plate. Results indicate that there are two different waves in this structure. One is the plasma mode that originates from the plasma surface wave propagating along the interface between the plasma and the quartz plate, and the other is the guide mode that originally travels along the vane-type slow wave structure. In contrast to its original slow wave characteristics, the guide mode becomes a fast wave in the low-frequency portion of the passband, and there exists a cut-off frequency for the guide mode. The vane-type guiding structure has been shown to limit the upper frequency of the passband of the plasma mode, compared with that of the plasma surface wave. In addition, the passband of the plasma mode increases with the plasma density while it becomes narrower for the guide mode. The influences of the parameters of the guiding structure and plasma density on the propagation of waves are also presented

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

    Energy Technology Data Exchange (ETDEWEB)

    Light, Samuel H.; Minasov, George; Shuvalova, Ludmilla; Duban, Mark-Eugene; Caffrey, Michael; Anderson, Wayne F.; Lavie, Arnon (NWU); (UIC)

    2012-02-27

    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 substrate and covalent pre- and post-dehydration reaction intermediates provide snapshots of successive steps along the type I DHQD-catalyzed reaction coordinate. These structures reveal that the position of the substrate within the active site does not appreciably change upon Schiff base formation. The intermediate state structures reveal a reaction state-dependent behavior of His-143 in which the residue adopts a conformation proximal to the site of catalytic dehydration only when the leaving group is present. We speculate that His-143 is likely to assume differing catalytic roles in each of its observed conformations. One conformation of His-143 positions the residue for the formation/hydrolysis of the covalent Schiff base intermediates, whereas the other conformation positions the residue for a role in the catalytic dehydration event. The fact that the shikimate pathway is absent from humans makes the enzymes of the pathway potential targets for the development of non-toxic antimicrobials. The structures and mechanistic insight presented here may inform the design of type I DHQD enzyme inhibitors.

  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. Chromosomal localization and structure of the human type II IMP dehydrogenase gene

    Energy Technology Data Exchange (ETDEWEB)

    Glesne, D.; Huberman, E. [Chicago Univ., IL (United States). Dept. of Molecular Genetics and Cell Biology]|[Argonne National Lab., IL (United States); Collart, F. [Argonne National Lab., IL (United States); Varkony, T.; Drabkin, H. [Colorado Univ., Denver, CO (United States). Health Sciences Center

    1994-05-01

    We determined the chromosomal localization and structure of the gene encoding human type II inosine 5{prime}-monophosphate dehydrogenase (IMPDH, EC 1.1.1.205), an enzyme associated with cellular proliferation, malignant transformation, and differentiation. Using polymerase chain reaction (PCR) primers specific for type II IMPDH, we screened a panel of human-Chinese hamster cell somatic hybrids and a separate deletion panel of chromosome 3 hybrids and localized the gene to 3p21.1{yields}p24.2. Two overlapping yeast artificial chromosome clones containing the full gene for type II IMPDH were isolated and a physical map of 117 kb of human genomic DNA in this region of chromosome 3 was constructed. The gene for type II IMPDH was localized and oriented on this map and found to span no more than 12.5 kb.

  20. 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.

  1. Production of fine structures in type III solar radio bursts due to turbulent density profiles

    International Nuclear Information System (INIS)

    Magnetic reconnection events in the corona release energetic electron beams along open field lines, and the beams generate radio emission at multiples of the electron plasma frequency fp to produce type III solar radio bursts. Type III bursts often exhibit irregularities in the form of flux modulations with frequency and/or local temporal advances and delays, and a type IIIb burst represents the extreme case where a type III burst is fragmented into a chain of narrowband features called striae. Remote and in situ spacecraft measurements have shown that density turbulence is ubiquitous in the corona and solar wind, and often exhibits a Kolmogorov power spectrum. In this work, we numerically investigate the effects of one-dimensional macroscopic density turbulence (along the beam direction) on the behavior of type III bursts, and find that this turbulence produces stria-like fine structures in the dynamic spectra of both fp and 2 fp radiation. Spectral and temporal fine structures in the predicted type III emission are produced by variations in the scattering path lengths and group speeds of radio emission, and in the locations and sizes of emitting volumes. Moderate turbulence levels yield flux enhancements with much broader half-power bandwidths in fp than 2 fp emission, possibly explaining the often observed type IIIb-III harmonic pairs as being where intensifications in 2 fp radiation are not resolved observationally. Larger turbulence levels producing trough-peak regions in the plasma density profile may lead to broader, resolvable intensifications in 2 fp radiation, which may account for the type IIIb-IIIb pairs that are sometimes observed.

  2. Production of fine structures in type III solar radio bursts due to turbulent density profiles

    Energy Technology Data Exchange (ETDEWEB)

    Loi, Shyeh Tjing; Cairns, Iver H.; Li, Bo, E-mail: sloi5113@uni.sydney.edu.au [School of Physics, The University of Sydney, New South Wales 2006 (Australia)

    2014-07-20

    Magnetic reconnection events in the corona release energetic electron beams along open field lines, and the beams generate radio emission at multiples of the electron plasma frequency f{sub p} to produce type III solar radio bursts. Type III bursts often exhibit irregularities in the form of flux modulations with frequency and/or local temporal advances and delays, and a type IIIb burst represents the extreme case where a type III burst is fragmented into a chain of narrowband features called striae. Remote and in situ spacecraft measurements have shown that density turbulence is ubiquitous in the corona and solar wind, and often exhibits a Kolmogorov power spectrum. In this work, we numerically investigate the effects of one-dimensional macroscopic density turbulence (along the beam direction) on the behavior of type III bursts, and find that this turbulence produces stria-like fine structures in the dynamic spectra of both f{sub p} and 2 f{sub p} radiation. Spectral and temporal fine structures in the predicted type III emission are produced by variations in the scattering path lengths and group speeds of radio emission, and in the locations and sizes of emitting volumes. Moderate turbulence levels yield flux enhancements with much broader half-power bandwidths in f{sub p} than 2 f{sub p} emission, possibly explaining the often observed type IIIb-III harmonic pairs as being where intensifications in 2 f{sub p} radiation are not resolved observationally. Larger turbulence levels producing trough-peak regions in the plasma density profile may lead to broader, resolvable intensifications in 2 f{sub p} radiation, which may account for the type IIIb-IIIb pairs that are sometimes observed.

  3. Growth of equilibrium structures built from a large number of distinct component types.

    Science.gov (United States)

    Hedges, Lester O; Mannige, Ranjan V; Whitelam, Stephen

    2014-09-14

    We use simple analytic arguments and lattice-based computer simulations to study the growth of structures made from a large number of distinct component types. Components possess 'designed' interactions, chosen to stabilize an equilibrium target structure in which each component type has a defined spatial position, as well as 'undesigned' interactions that allow components to bind in a compositionally-disordered way. We find that high-fidelity growth of the equilibrium target structure can happen in the presence of substantial attractive undesigned interactions, as long as the energy scale of the set of designed interactions is chosen appropriately. This observation may help explain why equilibrium DNA 'brick' structures self-assemble even if undesigned interactions are not suppressed [Ke et al. Science, 338, 1177, (2012)]. We also find that high-fidelity growth of the target structure is most probable when designed interactions are drawn from a distribution that is as narrow as possible. We use this result to suggest how to choose complementary DNA sequences in order to maximize the fidelity of multicomponent self-assembly mediated by DNA. We also comment on the prospect of growing macroscopic structures in this manner. PMID:25005537

  4. Impact of varying soil structure on transport processes in different diagnostic horizons of three soil types

    Science.gov (United States)

    Kodešová, Radka; Vignozzi, Nadia; Rohošková, Marcela; Hájková, Tereza; Ko?árek, Martin; Pagliai, Marcello; Kozák, Josef; Šim?nek, Jirka

    2009-02-01

    When soil structure varies in different soil types and the horizons of these soil types, it has a significant impact on water flow and contaminant transport in soils. This paper focuses on the effect of soil structure variations on the transport of pesticides in the soil above the water table. Transport of a pesticide (chlorotoluron) initially applied on soil columns taken from various horizons of three different soil types (Haplic Luvisol, Greyic Phaeozem and Haplic Cambisol) was studied using two scenarios of ponding infiltration. The highest infiltration rate and pesticide mobility were observed for the Bt 1 horizon of Haplic Luvisol that exhibited a well-developed prismatic structure. The lowest infiltration rate was measured for the Bw horizon of Haplic Cambisol, which had a poorly developed soil structure and a low fraction of large capillary pores and gravitational pores. Water infiltration rates were reduced during the experiments by a soil structure breakdown, swelling of clay and/or air entrapped in soil samples. The largest soil structure breakdown and infiltration decrease was observed for the Ap horizon of Haplic Luvisol due to the low aggregate stability of the initially well-aggregated soil. Single-porosity and dual-permeability (with matrix and macropore domains) flow models in HYDRUS-1D were used to estimate soil hydraulic parameters via numerical inversion using data from the first infiltration experiment. A fraction of the macropore domain in the dual-permeability model was estimated using the micro-morphological images. Final soil hydraulic parameters determined using the single-porosity and dual-permeability models were subsequently used to optimize solute transport parameters. To improve numerical inversion results, the two-site sorption model was also applied. Although structural changes observed during the experiment affected water flow and solute transport, the dual-permeability model together with the two-site sorption model proved to be able to approximate experimental data.

  5. 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)

  6. 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

  7. First structural evidence of sequestration of mRNA cap structures by type 1 ribosome inactivating protein from Momordica balsamina.

    Science.gov (United States)

    Kushwaha, Gajraj Singh; Yamini, Shavait; Kumar, Mukesh; Sinha, Mau; Kaur, Punit; Sharma, Sujata; Singh, Tej P

    2013-05-01

    This is the first structural evidence of recognition of mRNA cap structures by a ribosome inactivating protein. It is well known that a unique cap structure is formed at the 5' end of mRNA for carrying out various processes including mRNA maturation, translation initiation, and RNA turnover. The binding studies and crystal structure determinations of type 1 ribosome inactivating protein (RIP-1) from Momordica balsamina (MbRIP-1) were carried out with mRNA cap structures including (i) N7-methyl guanine (m7G), (ii) N7-methyl guanosine diphosphate (m7GDP), and (iii) N7-methyl guanosine triphosphate (m7GTP). These compounds showed affinities to MbRIP-1 at nanomolar concentrations. The structure determinations of the complexes of MbRIP-1 with m7G, m7GDP, and m7GTP at 2.65, 1.77, and 1.75 Å resolutions revealed that all the three compounds bound to MbRIP-1 in the substrate binding site at the positions which are slightly shifted towards Glu85 as compared to those of rRNA substrates. In this position, Glu85 forms several hydrogen bonds with guanine moiety while N-7 methyl group forms van der Waals contacts. However, the guanine rings are poorly stacked in these complexes. Thus, the mode of binding by MbRIP-1 to mRNA cap structures is different which results in the inhibition of depurination. Since some viruses are known to exploit the capping property of the host, this action of MbRIP-1 may have implications for the antiviral activity of this protein in vivo. The understanding of the mode of binding of MbRIP-1 to cap structures may also assist in the design of anti-viral agents. PMID:23280611

  8. 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.

  9. Crystal structure of Manduca sexta prophenoloxidase provides insights into the mechanism of type 3 copper enzymes

    Energy Technology Data Exchange (ETDEWEB)

    Li, Yongchao; Wang, Yang; Jiang, Haobo; Deng, Junpeng; (OKLU)

    2010-02-22

    Arthropod phenoloxidase (PO) generates quinones and other toxic compounds to sequester and kill pathogens during innate immune responses. It is also involved in wound healing and other physiological processes. Insect PO is activated from its inactive precursor, prophenoloxidase (PPO), by specific proteolysis via a serine protease cascade. Here, we report the crystal structure of PPO from a lepidopteran insect at a resolution of 1.97 {angstrom}, which is the initial structure for a PPO from the type 3 copper protein family. Manduca sexta PPO is a heterodimer consisting of 2 homologous polypeptide chains, PPO1 and PPO2. The active site of each subunit contains a canonical type 3 di-nuclear copper center, with each copper ion coordinated with 3 structurally conserved histidines. The acidic residue Glu-395 located at the active site of PPO2 may serve as a general base for deprotonation of monophenolic substrates, which is key to the ortho-hydroxylase activity of PO. The structure provides unique insights into the mechanism by which type 3 copper proteins differ in their enzymatic activities, albeit sharing a common active center. A drastic change in electrostatic surface induced on cleavage at Arg-51 allows us to propose a model for localized PPO activation in insects.

  10. Precision photonic band structure calculation of Abrikosov periodic lattice in type-II superconductors

    International Nuclear Information System (INIS)

    We have performed a numerical solution for band structure of an Abrikosov vortex lattice in type-II superconductors forming a periodic array in two dimensions for applications of incorporating the photonic crystals concept into superconducting materials with possibilities for optical electronics. The implemented numerical method is based on the extensive numerical solution of the Ginzburg-Landau equation for calculating the parameters of the two-fluid model and obtaining the band structure from the permittivity, which depends on the above parameters and the frequency. This is while the characteristics of such crystals highly vary with an externally applied static normal magnetic field, leading to nonlinear behavior of the band structure, which also has nonlinear dependence on the temperature. The similar analysis for every arbitrary lattice structure is also possible to be developed by this approach as presented in this work. We also present some examples and discuss the results

  11. Integrative analysis workflow for the structural and functional classification of C-type lectins

    Directory of Open Access Journals (Sweden)

    Koh Geoffrey

    2011-12-01

    Full Text Available Abstract Background It is important to understand the roles of C-type lectins in the immune system due to their ubiquity and diverse range of functions in animal cells. It has been observed that currently confirmed C-type lectins share a highly conserved domain known as the C-type carbohydrate recognition domain (CRD. Using the sequence profile of the CRD, an increasing number of putative C-type lectins have been identified. Hence, it is highly needed to develop a systematic framework that enables us to elucidate their carbohydrate (glycan recognition function, and discover their physiological and pathological roles. Results Presented herein is an integrated workflow for characterizing the sequence and structural features of novel C-type lectins. Our workflow utilizes web-based queries and available software suites to annotate features that can be found on the C-type lectin, given its amino acid sequence. At the same time, it incorporates modeling and analysis of glycans - a major class of ligands that interact with C-type lectins. Thereafter, the results are analyzed together with context-specific knowledge to filter off unlikely predictions. This allows researchers to design their subsequent experiments to confirm the functions of the C-type lectins in a systematic manner. Conclusions The efficacy and usefulness of our proposed immunoinformatics workflow was demonstrated by applying our integrated workflow to a novel C-type lectin -CLEC17A - and we report some of its possible functions that warrants further validation through wet-lab experiments.

  12. Identify Structural Flaw Location and Type with an Inverse Algorithm of Resonance Inspection

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Wei; Lai, Canhai; Sun, Xin

    2015-10-20

    To evaluate the fitness-for-service of a structural component and to quantify its remaining useful life, aging and service-induced structural flaws must be quantitatively determined in service or during scheduled maintenance shutdowns. Resonance inspection (RI), a non-destructive evaluation (NDE) technique, distinguishes the anomalous parts from the good parts based on changes in the natural frequency spectra. Known for its numerous advantages, i.e., low inspection cost, high testing speed, and broad applicability to complex structures, RI has been widely used in the automobile industry for quality inspection. However, compared to other contemporary direct visualization-based NDE methods, a more widespread application of RI faces a fundamental challenge because such technology is unable to quantify the flaw details, e.g. location, dimensions, and types. In this study, the applicability of a maximum correlation-based inverse RI algorithm developed by the authors is further studied for various flaw cases. It is demonstrated that a variety of common structural flaws, i.e. stiffness degradation, voids, and cracks, can be accurately retrieved by this algorithm even when multiple different types of flaws coexist. The quantitative relations between the damage identification results and the flaw characteristics are also developed to assist the evaluation of the actual state of health of the engineering structures.

  13. Structural and Electrical Properties of P--Type ZnO Thin Films

    International Nuclear Information System (INIS)

    The codoped ZnO thin film were deposited by DC magnetron sputtering on silicon (111) followed by annealing treatment at 200 deg. C to 600 deg. C for 1 hour in nitrogen and oxygen gas mixture. P-type conduction of Al-N codoped ZnO thin films were obtained at 300 deg. C with the lowest resistivity of 3.412x10-3 ?·cm and highest carrier concentration of 1.54x1022 cm-3. Structural investigation was carried out by atomic force microscope (AFM) and X-ray diffraction (XRD). Results showed that heat treatment had influenced the structure of the films

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

    DEFF Research Database (Denmark)

    Gourdon, Pontus Emanuel; Liu, Xiang-Yu; Skjørringe, Tina; Morth, J Preben; Møller, Lisbeth Birk; Pedersen, Bjørn Panyella; Nissen, Poul

    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 tran...

  15. Crystallographic structure of porcine adenovirus type 4 fiber head and galectin domains

    OpenAIRE

    Kahn, Richard; CURIEL, DAVID T.; Glasgow, Joel N.; Raaij, Mark J. van

    2010-01-01

    Adenovirus isolate NADC-1, a strain of porcine adenovirus type 4, has a fiber containing an N-terminal virus attachment region, shaft and head domains, and a C-terminal galectin domain connected to the head by an RGD-containing sequence. The crystal structure of the head domain is similar to previously solved adenovirus fiber head domains, but specific residues for binding the coxsackievirus and adenovirus receptor (CAR), CD46, or sialic acid are not conserved. The structure of the galectin d...

  16. Crystallographic Structure of Porcine Adenovirus Type 4 Fiber Head and Galectin Domains?

    OpenAIRE

    Guardado-Calvo, Pablo; Muñoz, Eva M.; Llamas-Saiz, Antonio L.; Fox, Gavin C.; Kahn, Richard; CURIEL, DAVID T.; Glasgow, Joel N.; Raaij, Mark J. van

    2010-01-01

    Adenovirus isolate NADC-1, a strain of porcine adenovirus type 4, has a fiber containing an N-terminal virus attachment region, shaft and head domains, and a C-terminal galectin domain connected to the head by an RGD-containing sequence. The crystal structure of the head domain is similar to previously solved adenovirus fiber head domains, but specific residues for binding the coxsackievirus and adenovirus receptor (CAR), CD46, or sialic acid are not conserved. The structure of the galectin d...

  17. Structure and Properties of {\\alpha}-NaFeO2-type Ternary Sodium Iridates

    OpenAIRE

    Baroudi, Kristen; Yim, Cindi; Wu, Hui; Huang, Qingzhen; Roudebush, John H.; Vavilova, Eugenia; Grafe, Hans-Joachim; Kataev, Vladislav; Buechner, Bernd; Ji, Huiwen; Kuo, Changyang; Hu, Zhiwei; Pi, Tun-Wen; Pao, Chiwen; Lee, Jyhfu

    2013-01-01

    The synthesis, structure, and elementary magnetic and electronic properties are reported for layered compounds of the type Na3-xMIr2O6 and Na3-xM2IrO6, where M is a transition metal from the 3d series (M=Zn, Cu, Ni, Co, Fe and Mn). The rhombohedral structures, in space group R-3m, were determined by refinement of neutron and synchrotron powder diffraction data. No clear evidence for long range 2:1 or 1:2 honeycomb-like M/Ir ordering was found in the neutron powder diffractio...

  18. Structural modeling of dahlia-type single-walled carbon nanohorn aggregates by molecular dynamics.

    Science.gov (United States)

    Hawelek, L; Brodka, A; Dore, John C; Hannon, Alex C; Iijima, S; Yudasaka, M; Ohba, T; Kaneko, K; Burian, A

    2013-09-19

    The structure of dahlia-type single-walled carbon nanohorn aggregates has been modeled by classical molecular dynamics simulations, and the validity of the model has been verified by neutron diffraction. Computer-generated models consisted of an outer part formed from single-walled carbon nanohorns with diameters of 20-50 Å and a length of 400 Å and an inner turbostratic graphite-like core with a diameter of 130 Å. The diffracted intensity and the pair correlation function computed for such a constructed model are in good agreement with the neutron diffraction experimental data. The proposed turbostratic inner core explains the occurrence of the additional (002) and (004) graphitic peaks in the diffraction pattern of the studied sample and provides information about the interior structure of the dahlia-type aggregates. PMID:23978218

  19. Structure and proton conduction in pyrochlore-type antimonic acid. A neutron diffraction study

    International Nuclear Information System (INIS)

    The structure of pyrochlore-type antimonic acid, HSbO3·0.5H2O, has been investigated using powder diffraction of neutrons. The structure (space group Fd3m) contains an [Sb2O62-] framework, with interstitial oxygens present as a mixture of H2O and H3O+. Three H-atom sites have been identified, (1) close to the [Sb2O62-] framework in hydroxyl groups (Sb-OH), (2) H in water molecules H-bonded to framework hydroxyls, and (3) H in H3O+ ions H-bonded to O-atoms of the intercavity windows. An intraframework equilibrium of the type Sb-OH+H2OSb-O-+H3O+ provides the mechanism for intracavity chemical exchange and proton conduction

  20. 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 and ligand-binding domains. Here, we report the crystal structure of T1414 and compare it with structurally similar drug and DNA-binding proteins

  1. 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.

  2. Multi-scale (FE2) analysis of material failure in cement/aggregate-type composite structures

    OpenAIRE

    Oliver Olivella, Xavier; Caicedo, Manuel Alejandro; Roubin, Emmanuel; Hernández Ortega, Joaquín Alberto; Huespe, Alfredo Edmundo

    2014-01-01

    The work propases a FP multiscale approach to computational modeling of material failure in concreteMlike structures, made of cement/aggregate-type composite materials. Keeping the approach in a classical homogenization setting, a multiscale model is proposed, which naturally provides a microscopic length-scale to be exported to the macrostructure. There, this length scale is used as regularization parameter in the context of the Continuum Strong Discontinuity Approach to material failure, an...

  3. 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.; Cynthia A. Berg; 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 model of relatio...

  4. Efficiency of different forest types in carbon storage depends on their internal structure

    OpenAIRE

    Iuliana F. Gheorghe; Iovu A. Biri?; Cristina M. Valcu

    2010-01-01

    Forest vegetation is a key factor in the maintenance of global carbon cycle balance under the present climate change conditions. Forest ecosystems are both buffers against extreme climatic events accompanying climate change and carbon sinks diminishing the environmental impact of anthropogenic greenhouse gas emissions. We investigated the influence of stand structure and site characteristics on the productivity and carbon storage capacity of temperate forest types. Predictors of species produ...

  5. Parametric identification of electric equipment with column-type structure. Part 2 - Experiment for parametric identification

    International Nuclear Information System (INIS)

    In the paper there is presented an experiment for the parametric identification of an electric equipment with column-type structure using the one point excitation method with steady-state sinusoidal vibration signals. On the basis of the determined modal parameters the numerical valuation of the dynamic response at mechanical stresses applied in its distinct points is done. (Author) 2 Figs., 1 Tab., 2 Refs

  6. 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 catalysis1. In prokaryotes and photosynthetic eukaryotes, Zn2+-transporting P-type ATPases of class IB (ZntA) are crucial for cellular redistribution and detoxification of Zn2+ and related elements2, 3. 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 Zn2+ 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 Zn2+ 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 Zn2+-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 Ca2+-ATPase4, 5 (SERCA) and Na+, K+-ATPase6. These findings considerably increase our understanding of zinc transport in cells and represent new possibilities for biotechnology and biomedicine.

  7. 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.

  8. Symmetry structure and solution of evolution-type equations with time dependent parameters in financial Mathematics

    OpenAIRE

    Okelola, Michael; Govinder, Keshlan

    2015-01-01

    Mathematical models with time dependent parameters are of great interest in financial Mathematics because they capture real life scenarios in the financial market. In this study, via the Lie group technique, we analyse evolution-type equations with time dependent parameters and give the general symmetry structure of these equations. In addition, we illustrate this method by looking at an example of exotic options called the power options. Our model parameters are time depend...

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

    OpenAIRE

    Satake, Ikuo

    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),...

  10. Structural Characterization of the UL25 DNA-Packaging Protein from Herpes Simplex Virus Type 1

    OpenAIRE

    Bowman, B. R.; Welschhans, R.L.; Jayaram, H; Stow, N D; Preston, V G; Quiocho, F. A.

    2006-01-01

    Herpesviruses replicate their double stranded DNA genomes as high-molecular-weight concatemers which are subsequently cleaved into unit-length genomes by a complex mechanism that is tightly coupled to DNA insertion into a preformed capsid structure, the procapsid. The herpes simplex virus type 1 UL25 protein is incorporated into the capsid during DNA packaging, and previous studies of a null mutant have demonstrated that its function is essential at the late stages of the head-filling process...

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

    DEFF Research Database (Denmark)

    Wang, Kaituo; Sitsel, Oleg; Meloni, Gabriele; Autzen, Henriette Elisabeth; Andersson, Magnus; Klymchuk, Tetyana; Nielsen, Anna Marie; Rees, Douglas C; Nissen, Poul; Gourdon, Pontus

    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 catalysis1. In prokaryotes and photosynthetic eukaryotes, Zn2+-transporting P-type ATPases of class IB (ZntA) are crucial for cellular redistribution and detoxification of Zn2+ and related elements2, 3. Here we present crystal structures representing the phosphoenzyme ground state (E2P) and a dephosphorylation...

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

    DEFF Research Database (Denmark)

    Engsig-Karup, Allan Peter; Hesthaven, Jan; Bingham, Harry B.; Warburton, T.

    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 f...

  13. Optical properties of crystals with incommensurate structure of Lifshitz’s type

    OpenAIRE

    O.G.Vlokh

    2000-01-01

    A review of optical properties of A2BX4 group crystals with incommensurate modulated structure of Lifshitz’s type a.i. crystals, which characterize nonequitranslation unit cell of high temperature and ordering - low temperature phases is done. The characteristics features of birefringence, optical activity, light absorption and the effects induced by the external influences (temperature, pressure, electric fields and mechanical stresses, X-ray radiation, as well as their gradients) are consid...

  14. Multilocus Sequence Typing Analysis of Staphylococcus lugdunensis Implies a Clonal Population Structure

    OpenAIRE

    Chassain, Benoît; Lemée, Ludovic; Didi, Jennifer; Thiberge, Jean-Michel; Brisse, Sylvain; Pons, Jean-Louis; Pestel-Caron, Martine

    2012-01-01

    Staphylococcus lugdunensis is recognized as one of the major pathogenic species within the genus Staphylococcus, even though it belongs to the coagulase-negative group. A multilocus sequence typing (MLST) scheme was developed to study the genetic relationships and population structure of 87 S. lugdunensis isolates from various clinical and geographic sources by DNA sequence analysis of seven housekeeping genes (aroE, dat, ddl, gmk, ldh, recA, and yqiL). The number of alleles ranged from four ...

  15. EVALUATION OF STRUCTURAL WOOD GLUED JOINT QUALITY, DEPENDING ON SELECTED TYPE OF AHDESIVE

    OpenAIRE

    ANNA BENESOVA; JAN VANEREK

    2012-01-01

    Structural wood glued joints are used to bond components of lamellar oragglomerated load-bearing members. Factor that influences the quality of the joint isthe sensitivity of wood mass to ambient humidity changes. Cyclic wetting and dryingof the timber leads to its volume changes and causes shear stress in the area of thebond line. Therefore, selected types of adhesives were tested according to a standardEN 302-1. In addition to shear strength assessment, a wood failure of specimens wasobserv...

  16. Direct Structure Determination of Multilayered Membrane-Type Systems Which Contain Fluid Layers

    Science.gov (United States)

    Worthington, C. R.; King, G. I.; McIntosh, T. J.

    1973-01-01

    The theory of direct methods of structure analysis in the case of multilayered membrane-type systems which contain fluid layers is described. Diffraction formulas for this kind of analysis are derived. Deconvolution methods are used when the centrosymmetrical unit cells contain wide fluid layers. When the membrane systems contain narrow fluid layers, other direct methods are used. These direct methods involve computing either the Fourier series representations or the sampling theorem expressions. PMID:4704487

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

    OpenAIRE

    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...

  18. Complex structure of type VI peptidoglycan muramidase effector and a cognate immunity protein

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Tianyu [Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Ding, Jinjing; Zhang, Ying; Wang, Da-Cheng, E-mail: dcwang@ibp.ac.cn [Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101 (China); Liu, Wei, E-mail: dcwang@ibp.ac.cn [The Third Military Medical University, Chongqing 400038 (China); Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101 (China)

    2013-10-01

    The structure of the Tse3–Tsi3 complex associated with the bacterial type VI secretion system of P. aeruginosa has been solved and refined at 1.9 Å resolution. The structural basis of the recognition of the muramidase effector and its inactivation by its cognate immunity protein is revealed. The type VI secretion system (T6SS) is a bacterial protein-export machine that is capable of delivering virulence effectors between Gram-negative bacteria. The T6SS of Pseudomonas aeruginosa transports two lytic enzymes, Tse1 and Tse3, to degrade cell-wall peptidoglycan in the periplasm of rival bacteria that are competing for niches via amidase and muramidase activities, respectively. Two cognate immunity proteins, Tsi1 and Tsi3, are produced by the bacterium to inactivate the two antibacterial effectors, thereby protecting its siblings from self-intoxication. Recently, Tse1–Tsi1 has been structurally characterized. Here, the structure of the Tse3–Tsi3 complex is reported at 1.9 Å resolution. The results reveal that Tse3 contains a C-terminal catalytic domain that adopts a soluble lytic transglycosylase (SLT) fold in which three calcium-binding sites were surprisingly observed close to the catalytic Glu residue. The electrostatic properties of the substrate-binding groove are also distinctive from those of known structures with a similar fold. All of these features imply that a unique catalytic mechanism is utilized by Tse3 in cleaving glycosidic bonds. Tsi3 comprises a single domain showing a ?-sandwich architecture that is reminiscent of the immunoglobulin fold. Three loops of Tsi3 insert deeply into the groove of Tse3 and completely occlude its active site, which forms the structural basis of Tse3 inactivation. This work is the first crystallographic report describing the three-dimensional structure of the Tse3–Tsi3 effector–immunity pair.

  19. ?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

  20. THE EFFECTS OF SEX, TOPOLOGICAL STRUCTURE, AND TASK TYPE ON HYPERTEXT NAVIGATIONAL PERFORMANCE.

    Science.gov (United States)

    Chang, Wen-Te; Chien, Yu-Hung

    2015-06-01

    Currently, almost all online materials use hyperlinks to provide users access to background, supplemental, or alternative information presented in context, greatly increasing the potential integration of information. However, a major problem is that people do not navigate hyperlinks effectively when the links become more topologically complex. Thus, identification of the variables that lead to navigational errors is necessary for the effective design of hyperlinks. Ninety-one participants (45 women, 46 men) were recruited for this experiment. All were college students and ranged in age from 19 to 23 yr. (M = 20.87, SD = 1.02). Navigational performance was examined in relation to sex, topological structure, and task type. A network topology with single-node task was superior to one with a linear topology under a single-node task condition, but equal to one with a linear topology under a multi-node task condition. Men navigated the linear topology with multi-node task and a network topology with a single-node task significantly faster than women, whereas no significant differences were observed under the other conditions. Sex interacted with topological structure and task type. This study extended the research in this domain by demonstrating an interactive effect among sex, topological structure, and task type on the navigational performance of users and can contribute to research regarding web page design. PMID:26057417

  1. Fine and Superfine Structure of the Decameter-Hectometer Type II Burst on 7 June 2011

    Science.gov (United States)

    Dorovskyy, V. V.; Melnik, V. N.; Konovalenko, A. A.; Brazhenko, A. I.; Panchenko, M.; Poedts, S.; Mykhaylov, V. A.

    2015-07-01

    The characteristics of a type II burst with a herringbone structure observed both with ground-based radio telescopes (UTR-2 and URAN-2) and space-borne spectrometers (STEREO-A and B) are discussed. The burst was recorded on 7 June 2011 in the frequency band 3 - 33 MHz. It was characterized by extremely rich fine structure. Statistical analysis of more than 300 herringbone sub-bursts constituting the burst was performed separately for the positively (reverse) and negatively (forward) drifting sub-bursts. The sense and the degree of circular polarization of the herringbone sub-bursts were measured in a wide frequency band (16 - 32 MHz). A second-order fine frequency structure of the herringbone sub-bursts was observed and studied for the first time. Using STEREO/COR1 and SOHO/LASCO-C2 images, we determined the direction and radial speed of the coronal mass ejection responsible for the studied type II burst. The possible location of the type II burst source on the flank of the shock was found.

  2. Fine and superfine structure of Decameter-Hectometer type II burst on 2011 June 7

    CERN Document Server

    Dorovskyy, V V; Konovalenko, A A; Brazhenko, A I; Panchenko, M; Poedts, S; Mykhaylov, V A

    2015-01-01

    The characteristics of the type II bursts with herringbone structure observed both by ground based radio telescopes (UTR-2, URAN-2) and spaceborn spectrometers (STEREO A-B) are discussed. The burst was recorded on 7 June, 2011 in the frequency band 3--33~MHz. It was characterized by extremely rich fine structure. The statistical analysis of more than 300 herringbone sub-bursts constituting the burst was performed separately for the positively (reverse) and negatively (forward) drifting sub-bursts. The sense and the degree of circular polarization of the herringbone sub-bursts were measured in the respectively wide frequency band (16--32~MHz). A second order fine frequency structure of the herringbone sub-bursts was firstly observed and processed. Using STEREO COR1 (A,B) and SOHO LASCO C2 images the direction and radial speed of the CME responsible for the studied type II burst were determined. The possible location of the type II burst source on the flank of the shock was found.

  3. [Soil microbial community structure of two types of forests in the mid-subtropics of China].

    Science.gov (United States)

    Han, Shi-zhong; Gao, Ren; Li, Ai-ping; Ma, Hong-liang; Yin, Yun-feng; Si, You-tao; Chen, Shi-dong; Zheng, Qun-rui

    2015-07-01

    Soil microbial community structures were analyzed by biomarker method of phospholipid fatty acid (PLFA) for a natural forest dominated by Castanopsis fabri (CF) and an adjacent plantation of Cunninghamia lanceolata (CL) in the mid-subtropics of China. The results showed that the amounts of total PLFAs, bacterial PLFAs, fungal PLFAs, gram-positive bacterial PLFAs and gramnegative bacterial PLFAs in the 0-10 cm soil layer were higher than in the 10-20 cm soil layer, and each type of PLFAs in CF were higher than in CL. In either soil layer of the two forest types, the contents of bacterial PLFAs were significantly higher than those of fungal PLFAs. In the two forests, the contents of bacterial PLFAs accounted for 44%-52% of total PLFAs, while the contents of fungal PLFAs just accounted for 6%-8%, indicating the bacteria were dominant in the soils of the two vegetation types. Principal component analysis showed that the influence of vegetation types was greater than soil depth on the microbial community structures. Correlation analysis showed that gram-negative bacterial PLFAs, gram-positive bacterial PLFAs and bacterial PLFAs were significantly negatively correlated with pH, positively with water content, and the PLFAs of main soil microorganism groups were significantly positively correlated with soil total nitrogen, organic carbon, C/N and ammonium. PMID:26710645

  4. Structural and functional analysis of C2-type ketoreductases from modular polyketide synthases.

    Science.gov (United States)

    Zheng, Jianting; Keatinge-Clay, Adrian T

    2011-07-01

    The process by which ?-stereocenters of polyketide intermediates are set by modular polyketide synthases (PKSs) when condensation is not immediately followed by reduction is mysterious. However, the reductase-incompetent ketoreductase (KR) from the third module of 6-deoxyerythronolide B synthase has been proposed to operate as a racemase, aiding in the epimerization process that reverses the orientation of the ?-methyl group of the polyketide intermediate generated by the ketosynthase to the configuration observed in the 6-deoxyerythronolide B final product. To learn more about the epimerization process, the structure of the C2-type KR from the third module of the pikromycin synthase, analogous to the KR from the third module of 6-deoxyerythronolide B synthase, was determined to 1.88 Å resolution. This first structural analysis of this KR-type reveals differences from reductase-competent KRs such as that the site NADPH binds to reductase-competent KRs is occluded by side chains and the putative catalytic tyrosine possesses more degrees of freedom. The active-site geometry may enable C2-type KRs to align the thioester and ?-keto groups of a polyketide intermediate to reduce the pK(a) of the ?-proton and accelerate its abstraction. Results from in vivo assays of engineered PKSs support that C2-type KRs cooperate with epimer-specific ketosynthases to set the configurations of substituent-bearing ?-carbons. PMID:21570406

  5. Structural analysis for glycolipid recognition by the C-type lectins Mincle and MCL.

    Science.gov (United States)

    Furukawa, Atsushi; Kamishikiryo, Jun; Mori, Daiki; Toyonaga, Kenji; Okabe, Yuki; Toji, Aya; Kanda, Ryo; Miyake, Yasunobu; Ose, Toyoyuki; Yamasaki, Sho; Maenaka, Katsumi

    2013-10-22

    Mincle [macrophage inducible Ca(2+)-dependent (C-type) lectin; CLEC4E] and MCL (macrophage C-type lectin; CLEC4D) are receptors for the cord factor TDM (trehalose-6,6'-dimycolate), a unique glycolipid of mycobacterial cell-surface components, and activate immune cells to confer adjuvant activity. Although it is known that receptor-TDM interactions require both sugar and lipid moieties of TDM, the mechanisms of glycolipid recognition by Mincle and MCL remain unclear. We here report the crystal structures of Mincle, MCL, and the Mincle-citric acid complex. The structures revealed that these receptors are capable of interacting with sugar in a Ca(2+)-dependent manner, as observed in other C-type lectins. However, Mincle and MCL uniquely possess shallow hydrophobic regions found adjacent to their putative sugar binding sites, which reasonably locate for recognition of fatty acid moieties of glycolipids. Functional studies using mutant receptors as well as glycolipid ligands support this deduced binding mode. These results give insight into the molecular mechanism of glycolipid recognition through C-type lectin receptors, which may provide clues to rational design for effective adjuvants. PMID:24101491

  6. Inhibition Kinetics And Emodin Cocrystal Structure of a Type II Polyketide Ketoreductase

    Energy Technology Data Exchange (ETDEWEB)

    Korman, T.P.; Tan, Y.-H.; Wong, J.; Luo, R.; Tsai, S.-C.

    2009-05-20

    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 well understood. The cocrystal structures of actinorhodin polyketide ketoreductase (actKR) bound with NADPH or NADP{sup +} and the inhibitor emodin were solved with the wild type and P94L mutant of actKR, revealing the first observation of a bent p-quinone in an enzyme active site. Molecular dynamics simulation help explain the origin of the bent geometry. Extensive screening for in vitro substrates shows that unlike FAS KR, the actKR prefers bicyclic substrates. Inhibition kinetics indicate that actKR follows an ordered Bi Bi mechanism. Together with docking simulations that identified a potential phosphopantetheine binding groove, the structural and functional studies reveal that the C9 specificity is a result of active site geometry and substrate ring constraints. The results lay the foundation for the design of novel aromatic polyketide natural products with different reduction patterns.

  7. Biogenesis and structure of a type VI secretion membrane core complex.

    Science.gov (United States)

    Durand, Eric; Nguyen, Van Son; Zoued, Abdelrahim; Logger, Laureen; Péhau-Arnaudet, Gérard; Aschtgen, Marie-Stéphanie; Spinelli, Silvia; Desmyter, Aline; Bardiaux, Benjamin; Dujeancourt, Annick; Roussel, Alain; Cambillau, Christian; Cascales, Eric; Fronzes, Rémi

    2015-07-30

    Bacteria share their ecological niches with other microbes. The bacterial type VI secretion system is one of the key players in microbial competition, as well as being an important virulence determinant during bacterial infections. It assembles a nano-crossbow-like structure in the cytoplasm of the attacker cell that propels an arrow made of a haemolysin co-regulated protein (Hcp) tube and a valine-glycine repeat protein G (VgrG) spike and punctures the prey's cell wall. The nano-crossbow is stably anchored to the cell envelope of the attacker by a membrane core complex. Here we show that this complex is assembled by the sequential addition of three type VI subunits (Tss)-TssJ, TssM and TssL-and present a structure of the fully assembled complex at 11.6 Å resolution, determined by negative-stain electron microscopy. With overall C5 symmetry, this 1.7-megadalton complex comprises a large base in the cytoplasm. It extends in the periplasm via ten arches to form a double-ring structure containing the carboxy-terminal domain of TssM (TssMct) and TssJ that is anchored in the outer membrane. The crystal structure of the TssMct-TssJ complex coupled to whole-cell accessibility studies suggest that large conformational changes induce transient pore formation in the outer membrane, allowing passage of the attacking Hcp tube/VgrG spike. PMID:26200339

  8. A new type of intelligent wireless sensing network for health monitoring of large-size structures

    Science.gov (United States)

    Lei, Ying; Liu, Ch.; Wu, D. T.; Tang, Y. L.; Wang, J. X.; Wu, L. J.; Jiang, X. D.

    2009-07-01

    In recent years, some innovative wireless sensing systems have been proposed. However, more exploration and research on wireless sensing systems are required before wireless systems can substitute for the traditional wire-based systems. In this paper, a new type of intelligent wireless sensing network is proposed for the heath monitoring of large-size structures. Hardware design of the new wireless sensing units is first studied. The wireless sensing unit mainly consists of functional modules of: sensing interface, signal conditioning, signal digitization, computational core, wireless communication and battery management. Then, software architecture of the unit is introduced. The sensing network has a two-level cluster-tree architecture with Zigbee communication protocol. Important issues such as power saving and fault tolerance are considered in the designs of the new wireless sensing units and sensing network. Each cluster head in the network is characterized by its computational capabilities that can be used to implement the computational methodologies of structural health monitoring; making the wireless sensing units and sensing network have "intelligent" characteristics. Primary tests on the measurement data collected by the wireless system are performed. The distributed computational capacity of the intelligent sensing network is also demonstrated. It is shown that the new type of intelligent wireless sensing network provides an efficient tool for structural health monitoring of large-size structures.

  9. Sloshing and fluid-structure interaction in a 400-MWe pool-type advanced fast reactor

    Energy Technology Data Exchange (ETDEWEB)

    Ma, D.C.; Gvildys, J.; Chang, Y.W.

    1987-01-01

    This paper describes the seismic analysis of a 400-MWe advanced fast reactor under 0.3 g SSE ground excitation. Two types of analyses are performed - the sloshing analysis and the fluid-structure interaction analysis. In the sloshing analysis, the sloshing frequency and wave patterns are calculated. The maximum wave height and the sloshing forces exerted on the submerged components and the primary tank are evaluated. In the fluid-structure interaction analysis, the maximum horizontal acceleration for the reactor core and the relative displacement between the reactor core and UIS are examined. The fluid-coupling phenomena between various components are investigated. Seismic stresses at critical areas are examined. The results obtained from this study are very useful to the design of the advanced reactors. Meanwhile, the computer code FLUSTR-ANL has proved to be a useful analytical tool for assessing the complicated seismic fluid-structure interactions and sloshing in the fast reactor systems. 10 refs., 25 figs.

  10. Sloshing and fluid-structure interaction in a 400-MWe pool-type advanced fast reactor

    International Nuclear Information System (INIS)

    This paper describes the seismic analysis of a 400-MWe advanced fast reactor under 0.3 g SSE ground excitation. Two types of analyses are performed - the sloshing analysis and the fluid-structure interaction analysis. In the sloshing analysis, the sloshing frequency and wave patterns are calculated. The maximum wave height and the sloshing forces exerted on the submerged components and the primary tank are evaluated. In the fluid-structure interaction analysis, the maximum horizontal acceleration for the reactor core and the relative displacement between the reactor core and UIS are examined. The fluid-coupling phenomena between various components are investigated. Seismic stresses at critical areas are examined. The results obtained from this study are very useful to the design of the advanced reactors. Meanwhile, the computer code FLUSTR-ANL has proved to be a useful analytical tool for assessing the complicated seismic fluid-structure interactions and sloshing in the fast reactor systems. 10 refs., 25 figs

  11. 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.

  12. Alternative conceptual design of a magnet support structure for plasma fusion devices of stellarator type

    International Nuclear Information System (INIS)

    Engineering design of magnet coil support structures for plasma fusion devices of the stellarator type are at present an important task in stellarator hardware R and D activities. In particular this is one of the basic core components in developing the stellarator's line in view of a robust and reliable fusion reactor. Based on long time experience in design and structural analyses of stellarator magnet systems and their support structure, the authors are proposing in this paper an alternative conceptual design for the magnet support structure. This paper describes the basic assumptions that a conceptual design of a magnet support structure has to fulfil. In this context, essential experiences gathered during manufacturing and assembly of the magnet support structure for a current stellarator fusion device engineered at Max Planck Institute for Plasma Physics are taken into account. The concept provides flexibility in matters of readjustment and positional optimization of the magnet coils during the assembly phase and potentially during the operation. The flexibility during the assembly phase allows a simplification of technical requirements and performance criteria which may result in a reduction of costs and improved reliability of a stellarator based power device.

  13. Mutational and structural analysis of Japanese patients with mucopolysaccharidosis type II.

    Science.gov (United States)

    Kato, Tomomi; Kato, Zenichiro; Kuratsubo, Izumi; Tanaka, Noboru; Ishigami, Tabito; Kajihara, Jun-Ichi; Sukegawa-Hayasaka, Kazuko; Orii, Koji; Isogai, Koji; Fukao, Toshiyuki; Shimozawa, Nobuyuki; Orii, Tadao; Kondo, Naomi; Suzuki, Yasuyuki

    2005-01-01

    We investigated mutations of the iduronate-2-sulfatase (I2S) gene and structural characteristics of I2S to clarify genotype/phenotype relationships in 18 Japanese patients with mucopolysaccharidosis type II. The I2S gene was analyzed in five patients with a severe phenotype and in 13 patients with an attenuated phenotype. The tertiary structural model of the human I2S was constructed by homology modeling using the arylsulfatase structure as a template. We identified four missense mutations and a nonsense mutation in the severe phenotype; four missense, two nonsense, three frame shifts, and one each of splice and amino acid deletion in the attenuated phenotype. Seven of them (L73del, Q75X, G140R, C171R, V401 fs, C422 fs, and H441 fs) were novel mutations. Structural analysis indicated that the residues of the mutations found in the severe phenotype would have direct interactions with the active site residues or should break the hydrophobic core domain of I2S, whereas residues of the missense mutations found in the attenuated phenotype were located in the peripheral region. In addition, effects by deletion or frameshift mutations could also be interpreted by the structure. Structural analysis of mutant proteins would help in understanding the genotype/phenotype relationships of Hunter disease. PMID:16133661

  14. 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.

  15. Oxide-ion conduction and dielectric relaxations for fluorite type structure

    International Nuclear Information System (INIS)

    The oxide-ion conduction and dielectric properties of 10 mol% CaO stabilized ZrO2 (10CSZ) and 25 mol% Y2O3 stabilized Bi2O3 (25YSB) which are oxide ion conductors having a fluorite-type structure were investigated. The numerical analyses for the frequency dependences of dielectric constants (?r') and dielectric loss factors (?r'') revealed that the dielectric properties were explained by Debye-type polarization due to dopant-vacancy associates and/or electrolyte-electrode interfacial polarization due to charging or loss current. No Debye-type polarization was observed in 25YSB because of no effective charge at the Y3+-doped Bi3+ site. On the other hand, two Debye-type dipoles observed in 10CSZ were assigned to two kinds of associates, [CaZr''-Vo··]·, which was due to dopant-vacancy associates with two different distances between (CaZr'') and (Vo··). The frequency dependence of dielectric loss tangent (tan?) in 25YSB was ascribed to the interface loss due to the charged current, while that of tan? in 8YSZ was ascribed to the Debye-type dipoles in addition to the interface loss.

  16. Comparative study on the effects of type 1 and type 2 diabetes on structural changes and hormonal output of the adrenal cortex in male Wistar rats

    Directory of Open Access Journals (Sweden)

    Elahi-Moghaddam Zohreh

    2013-01-01

    Full Text Available Abstract Introduction Diabetes is one of the most common endocrine disorders characterized by hyperglycemia due to defects in insulin secretion, insulin function, or both. Causing dysfunction in the body general metabolism, diabetes-induced chronic hyperglycemia leads to alterations in those endocrine glands involved in regulating the body metabolism. In this line, the present study has been conducted to investigate the effects of type 1 and type 2 diabetes on the structural changes and hormonal output of the adrenal cortex in male Wistar rat. Methods Eighteen male Wistar rats were divided into three groups including control, experimental type 1 diabetes (subcutaneous injection of 135 mg/kg alloxan and experimental type 2 diabetes (8 weeks treatment with drinking water containing 10% fructose. Two months after the induction of both types of diabetes, the level of blood biochemical factors (glucose, insulin, cortisol, triglycerides, cholesterol, LDL, and HDL were measured. Structural changes of the adrenal cortex were then evaluated, using stereological techniques. Results Serum biochemical analysis showed significant difference in the levels of glucose, triglycerides, insulin and cortisol in experimental groups, compared to the control. The results of structural alterations were also indicative of increase in adrenal cortex volume in both types of diabetes. Conclusion Probably through increasing HPA axis activity, type1 diabetes-induced hyperglycemia leads to adrenal hypertrophy and increase the hormonal output of adrenal gland.

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

    Energy Technology Data Exchange (ETDEWEB)

    Cai, Zhao-kun; Fan, Ping, E-mail: fanping308@126.com; Zheng, Zhuang-hao; Liu, Peng-juan; Chen, Tian-bao; Cai, Xing-min; Luo, Jing-ting; Liang, Guang-xing; Zhang, Dong-ping

    2013-09-01

    N-type bismuth telluride (Bi{sub 2}Te{sub 3}) 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 Bi{sub 2}Te{sub 3} film is achieved, which has a maximum thermoelectric power factor of 0.821 × 10{sup ?3} W m{sup ?1} K{sup ?2}. Furthermore, the dependence of Seebeck coefficient, electrical conductivity and power factor of the stoichiometric N-type Bi{sub 2}Te{sub 3} 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{sup ?3} W m{sup ?1} K{sup ?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.

  18. 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.

  19. Spectral structures and their generation mechanisms for solar radio type-I bursts

    International Nuclear Information System (INIS)

    The fine spectral structures of solar radio type-I bursts were observed by the solar radio telescope AMATERAS. The spectral characteristics, such as the peak flux, duration, and bandwidth, of the individual burst elements were satisfactorily detected by the highly resolved spectral data of AMATERAS with the burst detection algorithm that is improved in this study. The peak flux of the type-I bursts followed a power-law distribution with a spectral index of 2.9-3.3, whereas their duration and bandwidth were distributed more exponentially. There were almost no correlations between the peak flux, duration, and bandwidth. That means there was no similarity in the shapes of the burst spectral structures. We defined the growth rate of a burst as the ratio between its peak flux and duration. There was a strong correlation between the growth rate and peak flux. These results suggest that the free energy of type-I bursts that is originally generated by nonthermal electrons is modulated in the subsequent stages of the generation of nonthermal electrons, such as plasma wave generation, radio wave emissions, and propagation. The variation of the timescale of the growth rate is significantly larger than that of the coronal environments. These results can be explained by the situation wherein the source region may have the inhomogeneity of an ambient plasma environment, such as the boundary of open and closed field lines, and the superposition of entire emitted bursts was observed by the spectrometer.

  20. Predicting ?-turns and their types using predicted backbone dihedral angles and secondary structures

    Directory of Open Access Journals (Sweden)

    Hirst Jonathan D

    2010-07-01

    Full Text Available Abstract Background ?-turns are secondary structure elements usually classified as coil. Their prediction is important, because of their role in protein folding and their frequent occurrence in protein chains. Results We have developed a novel method that predicts ?-turns and their types using information from multiple sequence alignments, predicted secondary structures and, for the first time, predicted dihedral angles. Our method uses support vector machines, a supervised classification technique, and is trained and tested on three established datasets of 426, 547 and 823 protein chains. We achieve a Matthews correlation coefficient of up to 0.49, when predicting the location of ?-turns, the highest reported value to date. Moreover, the additional dihedral information improves the prediction of ?-turn types I, II, IV, VIII and "non-specific", achieving correlation coefficients up to 0.39, 0.33, 0.27, 0.14 and 0.38, respectively. Our results are more accurate than other methods. Conclusions We have created an accurate predictor of ?-turns and their types. Our method, called DEBT, is available online at http://comp.chem.nottingham.ac.uk/debt/.

  1. 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

  2. Three-dimensional structure of recombinant type 1 inositol 1,4,5-trisphosphate receptor

    Science.gov (United States)

    Wolfram, Francis; Morris, Edward; Taylor, Colin W.

    2010-01-01

    IP3Rs (inositol 1,4,5-trisphosphate receptors) are the intracellular channels that mediate release of Ca2+ from the endoplasmic reticulum in response to the many stimuli that evoke Ins(1,4,5)P3 formation. We characterized and purified type 1 IP3R heterologously expressed in Sf9 insect cells, and used the purified IP3R1 to determine its three-dimensional structure by electron microscopy and single-particle analysis. Recombinant IP3R1 has 4-fold symmetry with overall dimensions of approx. 19.5 nm×19.5 nm×17.5 nm. It comprises a small domain, which is likely to include the pore, linked by slender bridges to a large cytoplasmic domain with four petal-like regions. Our structures of recombinant IP3R1 and native cerebellar IP3R have similar appearances and dimensions. The only notable difference is the absence of a central stigma-like domain from the cytoplasmic region of recombinant IP3R1. The first structure of a recombinant IP3R is an important step towards developing three-dimensional structures of IP3R that better contribute to our understanding of the structural basis of IP3R activation. PMID:20377523

  3. Insect-inspired wing actuation structures based on ring-type resonators

    Science.gov (United States)

    Bolsman, Caspar T.; Goosen, Johannes F. L.; van Keulen, Fred

    2008-03-01

    In this paper, we illustrate and study the opportunities of resonant ring type structures as wing actuation mechanisms for a flapping wing Micro Air Vehicle (MAV). Various design alternatives are presented and studied based on computational and physical models. Insects provide an excellent source of inspiration for the development of the wing actuation mechanisms for flapping wing MAVs. The insect thorax is a structure which in essence provides a mechanism to couple the wing muscles to the wings while offering weight reduction through application of resonance, using tailored elasticity. The resonant properties of the thorax are a very effective way to reducing the power expenditure of wing movement. The wing movement itself is fairly complex and is guided by a set of control muscles and thoracic structures which are present in proximity of the wing root. The development of flapping wing MAVs requires a move away from classical structures and actuators. The use of gears and rotational electric motors is hard to justify at the small scale. Resonant structures provide a large design freedom whilst also providing various options for actuation. The move away from deterministic mechanisms offers possibilities for mass reduction.

  4. 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.).

  5. The Spectra of Type IIB Flux Compactifications at Large Complex Structure

    CERN Document Server

    Brodie, Callum

    2015-01-01

    We compute the spectra of the Hessian matrix, ${\\cal H}$, and the matrix ${\\cal M}$ that governs the critical point equation of the low-energy effective supergravity, as a function of the complex structure and axio-dilaton moduli space in type IIB flux compactifications at large complex structure. We find both spectra analytically in an $h^{1,2}_-+3$ real-dimensional subspace of the moduli space, and show that they exhibit a universal structure with highly degenerate eigenvalues, independently of the choice of flux, the details of the compactification geometry, and the number of complex structure moduli. In this subspace, the spectrum of the Hessian matrix contains no tachyons, but there are also no critical points. We show numerically that the spectra of ${\\cal H}$ and ${\\cal M}$ remain highly peaked over a large fraction of the sampled moduli space of explicit Calabi-Yau compactifications with 2 to 5 complex structure moduli. In these models, the scale of the supersymmetric contribution to the scalar masses...

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

    Energy Technology Data Exchange (ETDEWEB)

    Allen, C. Leigh; Gulick, Andrew M., E-mail: gulick@hwi.buffalo.edu [University at Buffalo, Buffalo, NY 14203 (United States)

    2014-06-01

    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.

  7. 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

  8. A study on structural changes in protein by time-division type Laue method

    International Nuclear Information System (INIS)

    In order to know the physiological roles of proteins, it is important to investigate the intermediate states of their structural changes. The sizes of proteins are generally several tens angstrom(A). Considering the resolution, only x-ray crystal analysis can be used in practice for the investigation of the mechanism of protein structural changes, though NMR is applicable only for small-sized proteins. However, x-ray analysis is not so suitable for analysis of their intermediate states. Thus, the author paid attention to the time-division type Laue method for the study of hemoglobin (Hb). Laser-flash induces to release carbonmonooxide (CO) from carboxyhemoglobin (Hb(CO)4). Therefore, if an appropriate length of x-ray pulse (?100 picosec) is available, the processes in the period from cleavage of the bond between a ligand (O2, CO or NO) and Hb to recombination of them might be monitored. Using DNA recombination and chemical modification techniques, recombinant Hb, of which T structure is stable was produced. An investigation on the conditions which allow to release CO from the Hb is undertaken using a single crystal of this Hb. The experimental systems applicable to time-division type Laue method are some protein molecules participating in chemical reactions inducible by light absorption, the electron-transfer system excited by light and so on. (M.N.)

  9. Prediction algorithm for amino acid types with their secondary structure in proteins (PLATON) using chemical shifts

    International Nuclear Information System (INIS)

    The algorithm PLATON is able to assign sets of chemical shifts derived from a single residue to amino acid types with its secondary structure (amino acid species). A subsequent ranking procedure using optionally two different penalty functions yields predictions for possible amino acid species for the given set of chemical shifts. This was demonstrated in the case of the ?-spectrin SH3 domain and applied to 9 further protein data sets taken from the BioMagRes database. A database consisting of reference chemical shift patterns (reference CSPs) was generated from assigned chemical shifts of proteins with known 3D-structure. This reference CSP database is used in our approach for extracting distributions of amino acid types with their most likely secondary structure elements (namely ?-helix, ?-sheet, and coil) for single amino acids by comparison with query CSPs. Results obtained for the 10 investigated proteins indicates that the percentage of correct amino acid species in the first three positions in the ranking list, ranges from 71.4% to 93.2% for the more favorable penalty function. Where only the top result of the ranking list for these 10 proteins is considered, 36.5% to 83.1% of the amino acid species are correctly predicted. The main advantage of our approach, over other methods that rely on average chemical shift values is the ability to increase database content by incorporating newly derived CSPs, and therefore to improve PLATON's performance over time

  10. 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.

  11. The centers of early-type galaxies with HST; 2, empirical models and structural parameters

    CERN Document Server

    Byun, Y I; Faber, S M; Ajhar, E A; Dressler, A; Kormendy, J; Lauer, T R; Richstone, D O; Tremaine, S

    1996-01-01

    We present a set of structural parameters for the central parts of 57 early-type galaxies observed with the Planetary Camera of the Hubble Space Telescope. These parameters are based on a new empirical law that successfully characterizes the centers of early type galaxies. This empirical law assumes that the surface brightness profile is a combination of two power laws with different slopes gamma and beta for the inner and outer regions. Conventional structural parameters such as core radius and central surface brightness are replaced by break radius r_b, where the transition between power-law slopes takes place, and surface brightness mu_b at that radius. An additional parameter alpha describes the sharpness of the break. The structural parameters are derived using a chi-squared minimization process applied to the mean surface brightness profiles. The resulting model profiles generally give very good agreement to the observed profiles out to the radius of 10 arcseconds imaged by the Planetary Camera. Excepti...

  12. Structural Biology Insight for the Design of Sub-type Selective Aurora Kinase Inhibitors.

    Science.gov (United States)

    Sarvagalla, Sailu; Coumar, Mohane Selvaraj

    2015-01-01

    Aurora kinase A, B and C, are key regulators of mitosis and are over expressed in many of the human cancers, making them an ideal drug target for cancer chemotherapy. Currently, over a dozen of Aurora kinase inhibitors are in various phases of clinical development. The majority of the inhibitors (VX-680/MK-0457, PHA-739358, CYC116, SNS-314, AMG 900, AT-9283, SCH- 1473759, ABT-348, PF-03814735, R-763/AS-703569, KW-2449 and TAK-901) are pan-selective (isoform non-selective) and few are Aurora A (MLN8054, MLN8237, VX-689/MK5108 and ENMD 2076) and Aurora B (AZD1152 and GSK1070916) sub-type selective. Despite the intensive research efforts in the past decade, no Aurora kinase inhibitor has reached the market. Recent evidence suggests that the sub-type selective Aurora kinase A inhibitor could possess advantages over pan-selective Aurora inhibitors, by avoiding Aurora B mediated neutropenia. However, sub-type selective Aurora kinase A inhibitor design is very challenging due to the similarity in the active site among the isoforms. Structural biology and computational aspects pertaining to the design of Aurora kinase inhibitors were analyzed and found that a possible means to develop sub-type selective inhibitor is by targeting Aurora A specific residues (Leu215, Thr217 and Arg220) or Aurora B specific residues (Arg159, Glu161 and Lys164), near the solvent exposed region of the protein. Particularly, a useful strategy for the design of sub-type selective Aurora A inhibitor could be by targeting Thr217 residue as in the case of MLN8054. Further preclinical and clinical studies with the sub-type selective Aurora inhibitors could help bring them to the market for the treatment of cancer. PMID:25895501

  13. 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.

  14. Structural and electronic properties of type-I and type-VIII Ba8Ga16Sn30 clathrates under compression

    International Nuclear Information System (INIS)

    The total energy and electronic structures for type-I (? phase) and type-VIII (? phase) Ba8Ga16Sn30 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 ??? phase transition can not occur under hydrostatic pressure. The band structures show that the type-I and type-VIII Ba8Ga16Sn30 are indirect semiconductors with band gaps of 0.24 eV and 0.19 eV, respectively. The results suggested that type-I clathrate Ba8Ga16Sn30 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 ?-phase, but it is not the case for ?-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 ?-phase and the increase of the band gap of ?-phase, indicating that the pressure effect can play an important role in the magnitude of the TE power.

  15. Function and Evolutionary Origin of Unicellular Camera-Type Eye Structure

    KAUST Repository

    Hayakawa, Shiho

    2015-03-03

    The ocelloid is an extraordinary eyespot organelle found only in the dinoflagellate family Warnowiaceae. It contains retina- and lens-like structures called the retinal body and the hyalosome. The ocelloid has been an evolutionary enigma because of its remarkable resemblance to the multicellular camera-type eye. To determine if the ocelloid is functionally photoreceptive, we investigated the warnowiid dinoflagellate Erythropsidinium. Here, we show that the morphology of the retinal body changed depending on different illumination conditions and the hyalosome manifests the refractile nature. Identifying a rhodopsin gene fragment in Erythropsidinium ESTs that is expressed in the retinal body by in situ hybridization, we also show that ocelloids are actually light sensitive photoreceptors. The rhodopsin gene identified is most closely related to bacterial rhodopsins. Taken together, we suggest that the ocelloid is an intracellular camera-type eye, which might be originated from endosymbiotic origin. © 2015 Hayakawa et al.

  16. 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.

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

    OpenAIRE

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

    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...

  18. Cation states of iron in complicated oxides with various derivative type of structure from perovskite

    International Nuclear Information System (INIS)

    Full text:The following oxides have been investigated: ortho ferrites (OF) LnFe2/3Mo1/3O3 (Ln = La, Ce, Pr, Nd), and oxygen-deficient perovskites with various structure types Pr4BaCu4FeOl3-? (? = 0, 0.5, type 4-1-5), Ln8-ySryCu8-xFexO20 (Ln = La, Nd, Pr, y=1.6-4, x = 1.6-3, type 8-8-20) and YBa2yLayCu3-xFexO7-?, Y1yCayBa2-yLayCu3-xFexO7-? (y = 0.25, 0.5, x = 0.06, 0.12, ?? 0.05, type 1-2-3). All investigated compounds are given by Institute of Chemistry of Ural branch of RAS (Ekaterinburg, G.V. Bazuev's laboratory). The Moessbauer spectroscopy on an isotope 57Fe was the basic method of researches. At some stages of researches as an additional method also X-ray analysis has been used. All considered types of perovskite-related structures are characterized by the general attribute of relationship - presence of layers, packages or skeletons from connected by tops octahedrons MeO6 (in our case Me = Cu, Fe, Mo) or their rests as pyramids MeO5, squares MeO4 and dumbbells MeO2 in oxygen-deficient compounds. The selection of samples (sequence of their research) was made so, that each subsequent structure row has the bigger 'deficiency' of oxygen in recalculation on an elementary cell of ideal perovskite (formula unit ABX3, where A, B -cations, X - anion): 1) ABX3 (OF); 2) A5B5X15-2=5xABX2.6 (4-1-5); 3) A8B8X24-4 = 8xABX2.5 (8-8-20); 4) A3B3X9-2 = 3xABX2.3 (1-2-3). The carried out studies show: 1) magnetic ordering of iron cations (at room temperature) in all researched oxides with the structures derivative from perovskite arises only in octahedral positions; It can be explained by the fact, that the increase in oxygen deficiency results in break of chains Fe-O-Fe through which there is an exchange interaction; 2) in OF and 4-1-5 oxides iron is only as Fe3+ in oxygen-deficient compounds of type 8-8-20 and 1-2-3 - in mixed valent state Fe3+ -Fe4+; i.e. to growth of deficiency of structural anions there is a displacement of a valent state of iron ions from '+3' to '+4'; 3) in OF Fe- and Mo- cations are statistically distributed on octahedral sites of structure; in compounds of type 4-1-5 and 8-8-20, iron placed in octahedral and pyramidal positions both independently of iron concentration; in oxides of type 1-2-3 iron substitutes copper only in positions Cu, having various oxygen coordination: from a square plane up to an octahedron; the majority iron atoms in perovskite-related structures are placed in octahedral positions, further on 'population' square pyramids and squares plane follow; it is explained following: at first place the iron ions prefer octahedral coordination, at second - in case of oxygen-deficient structures first two coordinations are resulted not only by substitution of copper in these positions, but also by attraction of additional oxygen in the environment; 4) the increase of oxygen deficiency results in downturn of symmetry of structural polyhedrons: the most symmetric polyhedrons in OF, further follow compounds of type 4-1-5, 8-8-20 and 1-2-3. The present work has been performed with the support of the grants of Tatarstan Academy of Sciences No. 06-6.1-142, CRDF (REC-007), Scientific School-1708.2003.2

  19. 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.

  20. 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.

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

    Science.gov (United States)

    Campuzano, Cuauhtemoc; Cordero, Rubén; Cruz, Miguel; Rojas, Efraín

    2015-04-01

    We show how the flat spacetime Galileon field theories (FSGFT) in arbitrary dimensions can be obtained through a Born-Infeld (BI) type structure. This construction involves a brane metric and nonlinear 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.

  2. Hamiltonian Structures and Integrability for a Discrete Coupled KdV-Type Equation Hierarchy

    International Nuclear Information System (INIS)

    Coupled Korteweg-de Vries (KdV) systems have many important physical applications. By considering a 4 × 4 spectral problem, we derive a discrete coupled KdV-type equation hierarchy. Our hierarchy includes the coupled Volterra system proposed by Lou et al. (e-print arXiv:0711.0420) as the first member which is a discrete version of the coupled KdV equation. We also investigate the integrability in the Liouville sense and the multi-Hamiltonian structures for the obtained hierarchy. (general)

  3. Hamiltonian structures and integrability for a discrete coupled KdV-type equation hierarchy

    International Nuclear Information System (INIS)

    Coupled Korteweg-de Vries (KdV) systems have many important physical applications. By considering a 4 × 4 spectral problem, we derive a discrete coupled KdV-type equation hierarchy. Our hierarchy includes the coupled Volterra system proposed by Lou et al. (e-print arXiv: 0711.0420) as the first member which is a discrete version of the coupled KdV equation. We also investigate the integrability in the Liouville sense and the multi-Hamiltonian structures for the obtained hierarchy. (authors)

  4. 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.

  5. 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.

  6. On the Structural Types of Reduplicative in The Book of Songs

    Directory of Open Access Journals (Sweden)

    Binghua DONG

    2011-12-01

    Full Text Available

    The Book of Songs is a collection of poems and songs in Chinese Qin Dynasty, in which featured by a lot of using of reduplicative. This paper, based on the results of previous scholars, analyzes the structural types of reduplicative inThe Book of Songsfrom the aspects of reduplicative in radical, in rhymes and both. This paper is aimed to better understand the meaning of The Book of Songs, so as to improve language teaching and practical using, as well as help with corpus and theories.

    Key words: The Book of Songs; Reduplicative; Structure; Reduplicative in radical; Reduplicative in rhymes

  7. Toothpaste lava: Characteristics and origin of a lava structural type transitional between pahoehoe and aa

    Science.gov (United States)

    Rowland, Scott K.; Walker, George P. L.

    1987-08-01

    Toothpaste lava, an important basalt structural type which illustrates the transition from pahoehoe to aa, is particularly well displayed on the 1960 Kapoho lava of Kilauea Volcano. Its transitional features stem from a viscosity higher than that of pahoehoe and a rate of flow slower than that of aa. Viscosity can be quantified by the limited settling of olivine phenocrysts and rate of flow by field observations related to the low-angle slope on which the lava flowed. Much can be learned about the viscosity, rheologic condition, and flow velocity of lavas long after solidification by analyses of their structural characteristics, and it is possible to make at least a semiquantitative assessment of the numerical values of these parameters.

  8. 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.

  9. Structure of zeolite catalysis of the pentasil type, modified simultaneously by boron and phosphorus compounds

    Energy Technology Data Exchange (ETDEWEB)

    Kubasov, A.A.; Kitaev, L.E.; Koldasheva, E.M.; Revokatov, O.P.; Petrusevich, Yu.M.

    1989-02-01

    Using x-ray phase analysis, IR and /sup 11/B NMR spectroscopy, the authors have studied the structure of pentasil type zeolites modified by boron and phosphorus compounds. They show that the modifier is chemically bonded to the zeolite, but does not displace the tetrahedrally coordinated atoms of the zeolite lattice. They observe BO/sub 3/ and BO/sub 4/ groups. The formation of BO/sub 4/ is explained by formation of borophosphate, and also by interaction of the B-containing component with OH groups of the zeolite. The presence of BO/sub 3/ is due to the boron anhydride impurity. They suggest the possibility of formation of polyphosphate structures also.

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

    International Nuclear Information System (INIS)

    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.)

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

    Energy Technology Data Exchange (ETDEWEB)

    McAfee, W.J.; Richardson, M.; Sartory, W.K.

    1977-05-12

    The creep deformation and rupture of type 304/308 stainless steel structural weldments at 593/sup 0/C (1100/sup 0/F) 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.

  12. 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

  13. 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

  14. 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.)

  15. 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

  16. Structure, function, evolution, and application of bacterial Pnu-type vitamin transporters.

    Science.gov (United States)

    Jaehme, Michael; Slotboom, Dirk Jan

    2015-09-01

    Many bacteria can take up vitamins from the environment via specific transport machineries. Uptake is essential for organisms that lack complete vitamin biosynthesis pathways, but even in the presence of biosynthesis routes uptake is likely preferred, because it is energetically less costly. Pnu transporters represent a class of membrane transporters for a diverse set of B-type vitamins. They were identified 30 years ago and catalyze transport by the mechanism of facilitated diffusion, without direct coupling to ATP hydrolysis or transport of coupling ions. Instead, directionality is achieved by metabolic trapping, in which the vitamin substrate is converted into a derivative that cannot be transported, for instance by phosphorylation. The recent crystal structure of the nicotinamide riboside transporter PnuC has provided the first insights in substrate recognition and selectivity. Here, we will summarize the current knowledge about the function, structure, and evolution of Pnu transporters. Additionally, we will highlight their role for potential biotechnological and pharmaceutical applications. PMID:26352203

  17. Local structure and effective pair potential of rock-salt type and disordered rock-salt type AgI under pressure

    International Nuclear Information System (INIS)

    X-ray absorption fine structure (XAFS) observations on iodine K edge of AgI have been performed under high pressure and high temperature up to 6.0 GPa and 1000K to investigate the local structure and effective potentials in high pressure phases. In EXAFS analysis, we have directly carried out the numerical integration of EXAFS function. The anharmonic effective pair potentials V(u)=au2/2+bu3/3! for I-Ag bond have been determined under pressures. ?-AgI and disordered rock-salt type phase have super-ionic conduction behaviors. Ag ions occupy both octahedral and tetrahedral sites in the disordered phase and twenty percent of Ag ions occupy the tetrahedral site as a maximum value at 2GPa. The transition between the rock-salt type and disordered rock-salt type phases is a broad disorder type within the same structure. From the viewpoint of the local structure analyses on XANES and EXAFS spectra, some sudden changes are recognized near the phase transition point. Pressure influences greatly the effective pair potential of anti-bonding side and anharmonicity decreases with increasing pressure. Phonon dispersion relation of the rock-salt type AgI under pressure has been derived from EXAFS experiments. Analysis of EXAFS Debye-Waller factor is useful because the force constant can be decided directly even at high pressure and high temperature

  18. 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.

  19. Relationships between NDVI, canopy structure, and photosynthesis in three California vegetation types

    International Nuclear Information System (INIS)

    In a range of plant species from three Californian vegetation types, we examined the widely used ''normalized difference vegetation index'' (NDVI) and ''simple ratio'' (SR) as indicators of canopy structure, light absorption, and photosynthetic activity. These indices, which are derived from canopy reflectance in the red and near-infrared wavebands, highlighted phenological differences between evergreen and deciduous canopies. They were poor indicators of total canopy biomass due to the varying abundance of non-green standing biomass in these vegetation types. However, in sparse canopies (leaf area index (LAI) apprxeq 0-2), NDVI was a sensitive indicator of canopy structure and chemical content (green biomass, green leaf area index, chlorophyll content, and foliar nitrogen content). At higher canopy green LAI values ( gt 2; typical of dense shrubs and trees), NDVI was relatively insensitive to changes in canopy structure. Compared to SR, NDVI was better correlated with indicators of canopy structure and chemical content, but was equivalent to the logarithm of SR. In agreement with theoretical expectations, both NDVI and SR exhibited near-linear correlations with fractional PAR intercepted by green leaves over a wide range of canopy densities. Maximum daily photosynthetic rates were positively correlated with NDVI and SR in annual grassland and semideciduous shrubs where canopy development and photosynthetic activity were in synchrony. The indices were also correlated with peak springtime canopy photosynthetic rates in evergreens. However, over most of the year, these indices were poor predictors of photosynthetic performance in evergreen species due to seasonal reductions in photosynthetic radiation-use efficiency that occurred without substantial declines in canopy greenness. Our results support the use of these vegetation indices as remote indicators of PAR absorption, and thus potential photosynthetic activity, even in heterogeneous landscapes. To provide accurate estimates of vegetation atmosphere gas fluxes, remote NDVI and SR measurements need to be coupled with careful estimates of canopy photosynthetic radiation-use efficiency. (author)

  20. Temperature dependence of the local structure and lattice dynamics of wurtzite-type ZnO

    International Nuclear Information System (INIS)

    Temperature-dependent (10–300 K) Zn K-edge extended X-ray absorption fine structure (EXAFS) spectra of polycrystalline wurtzite-type ZnO were analyzed using ab initio multiple-scattering theory and taking into account anisotropy of the crystallographic structure and thermal disorder. We employed two different simulation approaches: classical molecular dynamics (MD) and reverse Monte Carlo coupled with an evolutionary algorithm (RMC/EA method). The accuracy of several force-field models, which are commonly used in the MD simulations of bulk and nanostructured ZnO, was tested based on a comparison between the experimental and simulated Zn K-edge EXAFS spectra. It was found that available force-field models fail to describe accurately many-atom distribution functions. A more accurate solution was obtained with the RMC/EA method, which allowed us also to resolve the non-equivalent groups of atoms in the first two coordination shells around the absorbing Zn atom and to follow the changes of structural parameters as the temperature varied. It was found that upon increasing temperature the structure of ZnO becomes more anisotropic due to the increase of internal parameter u of the oxygen Wyckoff position (2b) and related Zn0–O2 distances

  1. UNIFIED CONTROL STRUCTURE OF MULTI-TYPE INTERIOR PERMANENT MAGNET MOTOR

    Directory of Open Access Journals (Sweden)

    M. NORHISAM

    2015-03-01

    Full Text Available This paper presents the control strategy structure to extract the speed torque characteristic for the newly designed three phase Multi Type Interior Permanent Magnet Motor. The proposed structure with the driving circuits exhibit the performance of torque characteristics of the stepper motor and brushless motor with independent coil winding per phase especially used as an in-wheel motor in agricultural applications. Brushless Direct Current motors exhibit characteristics of generating high torque at high speed while the Permanent Magnet Stepper motors has characteristic of generating high torque at low speed. The typical characteristics of the above two are integrated in the proposed structure with a complex control structure that handle the switching complexity and speed control in real time. Thus, a specially designed driving system is essential to drive and control this special motor. The evaluation of the motor mechanical characteristics when applying load torque is also presented. The result determines the practical torque range applicable for each motor configuration and as combined machine.

  2. 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 realistically pursue experimental behaviors. (author)

  3. Structure of a microsporidian methionine aminopeptidase type 2 complexed with fumagillin and TNP-470

    Energy Technology Data Exchange (ETDEWEB)

    Alvarado, J.; Nemkal, A; Sauder, J; Russell, M; Akiyoshi, D; Shi, W; Almo, S; Weiss, L

    2009-01-01

    Microsporidia are protists that have been reported to cause infections in both vertebrates and invertebrates. They have emerged as human pathogens particularly in patients that are immunosuppressed and cases of gastrointestinal infection, encephalitis, keratitis, sinusitis, myositis and disseminated infection are well described in the literature. While benzimidazoles are active against many species of microsporidia, these drugs do not have significant activity against Enterocytozoon bieneusi. Fumagillin and its analogues have been demonstrated to have activity in vitro and in animal models of microsporidiosis and human infections due to E. bieneusi. Fumagillin and its analogues inhibit methionine aminopeptidase type 2. Encephalitozoon cuniculi MetAP2 (EcMetAP2) was cloned and expressed as an active enzyme using a baculovirus system. The crystal structure of EcMetAP2 was determined with and without the bound inhibitors fumagillin and TNP-470. This structure classifies EcMetAP2 as a member of the MetAP2c family. The EcMetAP2 structure was used to generate a homology model of the E. bieneusi MetAP2. Comparison of microsporidian MetAP2 structures with human MetAP2 provides insights into the design of inhibitors that might exhibit specificity for microsporidian MetAP2.

  4. 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.

  5. Factor-analytic models for genotype × environment type problems and structured covariance matrices

    Directory of Open Access Journals (Sweden)

    Meyer Karin

    2009-01-01

    Full Text Available Abstract Background Analysis of data on genotypes with different expression in different environments is a classic problem in quantitative genetics. A review of models for data with genotype × environment interactions and related problems is given, linking early, analysis of variance based formulations to their modern, mixed model counterparts. Results It is shown that models developed for the analysis of multi-environment trials in plant breeding are directly applicable in animal breeding. In particular, the 'additive main effect, multiplicative interaction' models accommodate heterogeneity of variance and are characterised by a factor-analytic covariance structure. While this can be implemented in mixed models by imposing such structure on the genetic covariance matrix in a standard, multi-trait model, an equivalent model is obtained by fitting the common and specific factors genetic separately. Properties of the mixed model equations for alternative implementations of factor-analytic models are discussed, and extensions to structured modelling of covariance matrices for multi-trait, multi-environment scenarios are described. Conclusion Factor analytic models provide a natural framework for modelling genotype × environment interaction type problems. Mixed model analyses fitting such models are likely to see increasing use due to the parsimonious description of covariance structures available, the scope for direct interpretation of factors as well as computational advantages.

  6. Synthesis, structural transformation, thermal stability, valence state, and magnetic and electronic properties of PbNiO3 with perovskite- and LiNbO3-type structures.

    Science.gov (United States)

    Inaguma, Yoshiyuki; Tanaka, Kie; Tsuchiya, Takeshi; Mori, Daisuke; Katsumata, Tetsuhiro; Ohba, Tomonori; Hiraki, Ko-ichi; Takahashi, Toshihiro; Saitoh, Hiroyuki

    2011-10-26

    We synthesized two high-pressure polymorphs PbNiO(3) with different structures, a perovskite-type and a LiNbO(3)-type structure, and investigated their formation behavior, detailed structure, structural transformation, thermal stability, valence state of cations, and magnetic and electronic properties. A perovskite-type PbNiO(3) synthesized at 800 °C under a pressure of 3 GPa crystallizes as an orthorhombic GdFeO(3)-type structure with a space group Pnma. The reaction under high pressure was monitored by an in situ energy dispersive X-ray diffraction experiment, which revealed that a perovskit-type phase was formed even at 400 °C under 3 GPa. The obtained perovskite-type phase irreversibly transforms to a LiNbO(3)-type phase with an acentric space group R3c by heat treatment at ambient pressure. The Rietveld structural refinement using synchrotron X-ray diffraction data and the XPS measurement for both the perovskite- and the LiNbO(3)-type phases reveal that both phases possess the valence state of Pb(4+)Ni(2+)O(3). Perovskite-type PbNiO(3) is the first example of the Pb(4+)M(2+)O(3) series, and the first example of the perovskite containing a tetravalent A-site cation without lone pair electrons. The magnetic susceptibility measurement shows that the perovskite- and LiNbO(3)-type PbNiO(3) undergo antiferromagnetic transition at 225 and 205 K, respectively. Both the perovskite- and LiNbO(3)-type phases exhibit semiconducting behavior. PMID:21888429

  7. High-pressure synthesis of ferromagnetic Mn3Ge with the Cu3Au-type structure

    Science.gov (United States)

    Takizawa, H.; Yamashita, T.; Uheda, K.; Endo, T.

    2002-11-01

    A new intermetallic compound, Mn3Ge, has been synthesized by direct reaction of elemental components at 6.2 GPa and 1000°C for 30 min using a belt-type high-pressure apparatus. The compound crystallizes into a cubic structure with the space group Pm3m, namely the L12-type (Cu3Au-type) structure. The structure was refined by Rietveld analysis of the powder x-ray diffraction data and the lattice constant was determined as a = 0.380 19(3) nm. The compound shows metallic conductivity and ferromagnetism with a Curie temperature of 400 K.

  8. 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.

  9. Crystal structure of a Kunitz-type trypsin inhibitor from Erythrina caffra seeds.

    Science.gov (United States)

    Onesti, S; Brick, P; Blow, D M

    1991-01-01

    The trypsin inhibitor DE-3 from Erythrina caffra (ETI) belongs to the Kunitz-type soybean trypsin inhibitor (STI) family and consists of 172 amino acid residues with two disulphide bridges. The amino acid sequence of ETI shows high homology to other trypsin inhibitors from the same family but ETI has the unique ability to bind and inhibit tissue plasminogen activator. The crystal structure of ETI has been determined using the method of isomorphous replacement and refined using a combination of simulated annealing and conventional restrained least-squares crystallographic refinement. The refined model includes 60 water molecules and 166 amino acid residues, with a root-mean-square deviation in bond lengths from ideal values of 0.016 A. The crystallographic R-factor is 20.8% for 7770 independent reflections between 10.0 and 2.5 A. The three-dimensional structure of ETI consists of 12 antiparallel beta-strands joined by long loops. Six of the strands form a short antiparallel beta-barrel that is closed at one end by a "lid" consisting of the other six strands coupled in pairs. The molecule shows approximate 3-fold symmetry about the axis of the barrel, with the repeating unit consisting of four sequential beta-strands and the connecting loops. Although there is no sequence homology, this same fold is present in the structure of interleukin-1 alpha and interleukin-1 beta. When the structure of ETI and interleukin-1 beta are superposed, the close agreement between the alpha-carbon positions for the beta-strands is striking. The scissile bond (Arg63-Ser64) is located on an external loop that protrudes from the surface of the molecule and whose architecture is not constrained by secondary structure elements, disulphide bridges or strong electrostatic interactions. The hydrogen bonds made by the side-chain amide group of Asn12 play a key role in maintaining the three-dimensional structure of the loop. This residue is in a position corresponding to that of a conserved asparagine in the Kazal inhibitor family. Although the overall structure of ETI is similar to the partial structure of STI, the scissile bond loop is displaced by about 4 A. This displacement probably arises from the fact that the structure of STI has been determined in a complex with trypsin but could possibly be a consequence of the close molecular contact between Arg63 and an adjacent molecule in the crystal lattice. PMID:1988676

  10. Nuclear Structure and the Fate of Core Collapse (Type II) Supernova

    CERN Document Server

    Gai, Moshe

    2014-01-01

    For a long time Gerry Brown and his collaborator Hans Bethe considered the question of the final fate of a core collapse (Type II) supernova. Recalling ideas from nuclear structure on Kaon condensate and a soft equation of state of the dense nuclear matter they concluded that progenitor stars with mass as low a 17-18M$_\\odot$ (including supernova 1987A) could collapse to a small mass black hole with a mass just beyond 1.5M$_\\odot$, the upper bound they derive for a neutron star. We discuss another nuclear structure effect that determines the carbon to oxygen ratio (C/O) at the end of helium burning. This ratio also determines the fate of a Type II supernova with a carbon rich progenitor star producing a neutron star and oxygen rich collapsing to a black hole. While the C/O ratio is one of the most important nuclear input to stellar evolution it is still not known with sufficient accuracy. We discuss future efforts to measure with gamma-beam and TPC detector the 12C(a,g)16O reaction that determines the C/O rat...

  11. Crystal structure of Eu-doped magnetoplumbite-type lanthanum aluminum oxynitride with emission site splitting

    International Nuclear Information System (INIS)

    Eu-doped lanthanum aluminum oxynitride (LaAl12(O,N)19) with magnetoplumbite structure was prepared by nitridation of the oxide precursor obtained from aluminum glycine gel and subsequent post-annealing. Eu-doped lanthanum aluminum oxynitride exhibited blue light emission at 440 nm with a shoulder at 464 nm under excitation at 254 nm. Isostructural Eu-doped calcium aluminum oxide (CaAl12O19) exhibited a single emission peak at 415 nm. Structural refinement using neutron powder diffraction indicated that the lanthanum site occupied partially by Eu2+ splits into 2d and 6h sites in the aluminum oxynitride. The longer emission and the shoulder peak in the former aluminum oxynitride were observed in relation to the increasing covalency as well as crystal field splitting around doped Eu2+ induced by site splitting involved with the two kinds of anions. - Graphical Abstract: Magnetoplumbite type Eu-doped lanthanum aluminum oxynitride has lanthanum site splitting induced by two kinds of anions, causing two emission peaks. Highlights: ? Magnetoplumbite type LaAl12(O,N)19 doped with Eu shows emission peak splitting. ? ND analysis is performed on La0.97Eu0.03Al12(O,N)19 and Ca0.97Eu0.03Al12O19. ? La0.97Eu0.03Al12(O,N)19 has lanthanum site splitting. ? The lanthanum site splitting is induced by coexisting of two kinds of anions.

  12. Structural, dielectric, magnetic, and nuclear magnetic resonance studies of multiferroic Y-type hexaferrites

    Science.gov (United States)

    Khanduri, H.; Chandra Dimri, M.; Kooskora, H.; Heinmaa, I.; Viola, G.; Ning, H.; Reece, M. J.; Krustok, J.; Stern, R.

    2012-10-01

    The effect of strontium substitution on structural, magnetic, and dielectric properties of a multiferroic Y-type hexaferrite (chemical formula Ba2-xSrxMg2Fe12O22 with 0 ? x ? 2) was investigated. Y-type hexaferrite phase formation was not affected by strontium substitution for barium, in the range 0 ? x ? 1.5, confirmed by x-ray diffraction and Raman spectroscopy measured at room temperature. Two intermediate magnetic spin phase transitions (at tempertures TI and TII) and a ferrimagnetic-paramagnetic transition (at Curie temperature TC) were identified from the temperature dependence of the magnetic susceptibility. Magnetic transition temperatures (TI, TII, and TC) increased with increasing strontium content. Magnetic hysteresis measurements indicated that by increasing strontium concentration, the coercivity increases, while the saturation magnetization decreases. The 57Fe NMR spectrum of the Y-type hexaferrite measured at 5 K and in zero magnetic field showed remarkable differences compared to that of other hexaferrites due to their different number of tetrahedral and octahedral iron sites. The temperature and frequency dependence of the dielectric permittivity evidenced broad peaks with frequency dispersion in correspondence of the Curie temperature.

  13. Structure and stability of Ba-Cu-Ge type-I clathrates

    CERN Document Server

    Li, Y; Gou, W; Khandekar, S; Li, Yang; Chi, Ji; Gou, Weiping; Khandekar, Sameer; Jr, Joseph H. Ross

    2003-01-01

    We have prepared samples of nominal type Ba$_{8}$Cu$_{x}$Ge$_{46-x}$ by induction melting and solid state reaction. Analysis has shown that these materials form type-I clathrates, with copper content between $x$ = 4.6 and 5.2, nearly independent of the starting composition. X-ray powder diffraction and single-crystal electron diffraction results confirmed the cubic type-I clathrate structure to be the main phase in these materials. For starting compositions of Ba$_{8}$Cu$_{2}$Ge$_{44}$ and Ba$_{8}$Cu$_{4}$Ge$_{42}$, electron microprobe analysis demonstrated the formation of clathrate with average composition Ba$_{7.8}$Cu$_{4.7}$Ge$_{39.3}$, along with elemental Ge and a small amount of BaGeO$_{2}$. In a Ba$_{8}$Cu$_{6}$Ge$_{40}$ preparation, Cu content of the clathrate phase increased to x = 5.1, while excess Cu appeared as a Ge$_{3}$Cu$_{5}$ phase. The stability of the $x \\approx$ 5 composition in Ba$_{8}$Cu$_{x}$Ge$_{46-x}$ we attribute to an electron magic-number mechanism, associated with a gap or deep mi...

  14. Structure and electrical properties of p-type twin ZnTe nanowires

    International Nuclear Information System (INIS)

    Resonant tunneling is firstly found in twin p-type ZnTe nanowire field-effect transistors. The twin ZnTe nanowires are synthesized via the thermal evaporation process. X-ray diffraction and high-resolution transmission electron microscopy characterization indicate that the as-grown twin nanowire has a zinc-blende crystal structure with an integrated growth direction of [11-1]. The twin plane is (11-1) and the angle between the mirror symmetrical planes is 141 . The formation of twins is attributed to the surface tension from the eutectic liquid droplet. Field-effect transistors based on single ZnTe twin nanowire are constructed, the corresponding electrical measurements demonstrate that the twin nanowires have a p-type conductivity with a mobility (?h) of 0.11 cm 2 V -1 S -1, and a carrier concentration (nh) of 1.1 x 10 17 cm -3. Significantly, the negative differential resistance with a peak-to-valley current ratio of about 1.3 is observed in p-type twin ZnTe nanowire field-effect transistors at room temperature. As the periodic barriers produced in the periodic twin interfaces can form multi-barrier and multi-well along one-dimensional direction. The multibarrier can be modulated under external electrical field. When the resonant condition is met, the space charge will be enhanced with the inherent feedback mechanism, and the resonant tunneling will occur. (orig.)

  15. 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

  16. 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.

  17. Structures and properties of ThCr2Si2-type superconductors and related materials

    International Nuclear Information System (INIS)

    Work on this thesis started in 2008, only a few months after the discovery of superconductivity in doped BaFe2As2. The first goal at that time was the investigation of further compounds crystallizing in the ThCr2Si2-type structure with respect to phase transitions, magnetic properties and possible superconductivity. One candidate that seemed to be very similar to BaFe2As2 because of its structural phase transitions, was SrRh2As2. However, a closer look revealed a more complicated and challenging structural chemistry. The first two chapters of this work are devoted to the study and solution of the intriguing crystallographic problems of the three SrRh2As2 phases and the characterization of further ternary rhodium arsenides. Furthermore, high quality single crystals of Ba1-xKxFe2As2 were synthesized and single crystals as well as powder samples of Ba1-xKxFe2As2 were investigated with synchrotron X-ray diffraction methods as described in chapters 5 and 6. Finally, the last part of this thesis concentrates on the question which effects of doping are actually responsible for the occurrence of superconductivity in BaFe2As2. Is the superconductivity induced by the alteration of charge in the FeAs4/4-layer, by the disorder introduced by doping, or by the structural changes? To help elucidate this issue, several substitution series of 122-iron arsenides were prepared and the influence of hole and electron or charge and isoelectronic doping on superconductivity, magnetic and structural properties and their mutual relationship was studied (chapters 7,8,9 and 10).

  18. 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.

  19. Structural and dynamic properties that govern the stability of an engineered fibronectin type III domain.

    Science.gov (United States)

    Porebski, Benjamin T; Nickson, Adrian A; Hoke, David E; Hunter, Morag R; Zhu, Liguang; McGowan, Sheena; Webb, Geoffrey I; Buckle, Ashley M

    2015-03-01

    Consensus protein design is a rapid and reliable technique for the improvement of protein stability, which relies on the use of homologous protein sequences. To enhance the stability of a fibronectin type III (FN3) domain, consensus design was employed using an alignment of 2123 sequences. The resulting FN3 domain, FN3con, has unprecedented stability, with a melting temperature >100°C, a ?G(D-N) of 15.5 kcal mol(-1) and a greatly reduced unfolding rate compared with wild-type. To determine the underlying molecular basis for stability, an X-ray crystal structure of FN3con was determined to 2.0 Å and compared with other FN3 domains of varying stabilities. The structure of FN3con reveals significantly increased salt bridge interactions that are cooperatively networked, and a highly optimized hydrophobic core. Molecular dynamics simulations of FN3con and comparison structures show the cooperative power of electrostatic and hydrophobic networks in improving FN3con stability. Taken together, our data reveal that FN3con stability does not result from a single mechanism, but rather the combination of several features and the removal of non-conserved, unfavorable interactions. The large number of sequences employed in this study has most likely enhanced the robustness of the consensus design, which is now possible due to the increased sequence availability in the post-genomic era. These studies increase our knowledge of the molecular mechanisms that govern stability and demonstrate the rising potential for enhancing stability via the consensus method. PMID:25691761

  20. Structural and dynamic properties that govern the stability of an engineered fibronectin type III domain

    Science.gov (United States)

    Porebski, Benjamin T.; Nickson, Adrian A.; Hoke, David E.; Hunter, Morag R.; Zhu, Liguang; McGowan, Sheena; Webb, Geoffrey I.; Buckle, Ashley M.

    2015-01-01

    Consensus protein design is a rapid and reliable technique for the improvement of protein stability, which relies on the use of homologous protein sequences. To enhance the stability of a fibronectin type III (FN3) domain, consensus design was employed using an alignment of 2123 sequences. The resulting FN3 domain, FN3con, has unprecedented stability, with a melting temperature >100°C, a ?GD?N of 15.5 kcal mol?1 and a greatly reduced unfolding rate compared with wild-type. To determine the underlying molecular basis for stability, an X-ray crystal structure of FN3con was determined to 2.0 Å and compared with other FN3 domains of varying stabilities. The structure of FN3con reveals significantly increased salt bridge interactions that are cooperatively networked, and a highly optimized hydrophobic core. Molecular dynamics simulations of FN3con and comparison structures show the cooperative power of electrostatic and hydrophobic networks in improving FN3con stability. Taken together, our data reveal that FN3con stability does not result from a single mechanism, but rather the combination of several features and the removal of non-conserved, unfavorable interactions. The large number of sequences employed in this study has most likely enhanced the robustness of the consensus design, which is now possible due to the increased sequence availability in the post-genomic era. These studies increase our knowledge of the molecular mechanisms that govern stability and demonstrate the rising potential for enhancing stability via the consensus method. PMID:25691761

  1. Musical structural determinants of emotional judgments in dementia of the Alzheimer type.

    Science.gov (United States)

    Gagnon, Lise; Peretz, Isabelle; Fülöp, Tamàs

    2009-01-01

    People with dementia of the Alzheimer type (DAT) may well be emotionally soothed by listening to music. However, very few systematic studies have been conducted to support the anecdotal evidence. DAT does damage certain cerebral structures that subsume emotional processing, and some studies have demonstrated deficits affecting emotional judgments of facial expression and prosody in DAT. Accordingly, this study addressed the question of whether DAT might leave musical emotional judgment intact. Twelve early DAT participants and 12 healthy elderly participants took part in this study. Emotional judgments were examined in relation to mode and tempo, two important structural properties that contribute to the happy-sad distinction in music. Their respective contributions were assessed in four different experimental conditions. The DAT participants' responses were similar to those of healthy elderly participants, showing spared ability to employ tempo and mode as cues for emotional interpretation. The DAT participants' performance was not correlated with their global cognitive functioning. These results constitute a preliminary empirical demonstration that, in early DAT, musical emotional judgments appear to be based on normal structural analysis of musical input. PMID:19210036

  2. 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

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

    DEFF Research Database (Denmark)

    Gourdon, Pontus Emanuel; 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.

  4. Crystallographic Structure of Porcine Adenovirus Type 4 Fiber Head and Galectin Domains?

    Science.gov (United States)

    Guardado-Calvo, Pablo; Muñoz, Eva M.; Llamas-Saiz, Antonio L.; Fox, Gavin C.; Kahn, Richard; Curiel, David T.; Glasgow, Joel N.; van Raaij, Mark J.

    2010-01-01

    Adenovirus isolate NADC-1, a strain of porcine adenovirus type 4, has a fiber containing an N-terminal virus attachment region, shaft and head domains, and a C-terminal galectin domain connected to the head by an RGD-containing sequence. The crystal structure of the head domain is similar to previously solved adenovirus fiber head domains, but specific residues for binding the coxsackievirus and adenovirus receptor (CAR), CD46, or sialic acid are not conserved. The structure of the galectin domain reveals an interaction interface between its two carbohydrate recognition domains, locating both sugar binding sites face to face. Sequence evidence suggests other tandem-repeat galectins have the same arrangement. We show that the galectin domain binds carbohydrates containing lactose and N-acetyl-lactosamine units, and we present structures of the galectin domain with lactose, N-acetyl-lactosamine, 3-aminopropyl-lacto-N-neotetraose, and 2-aminoethyl-tri(N-acetyl-lactosamine), confirming the domain as a bona fide galectin domain. PMID:20686025

  5. Crystallographic structure of porcine adenovirus type 4 fiber head and galectin domains.

    Science.gov (United States)

    Guardado-Calvo, Pablo; Muñoz, Eva M; Llamas-Saiz, Antonio L; Fox, Gavin C; Kahn, Richard; Curiel, David T; Glasgow, Joel N; van Raaij, Mark J

    2010-10-01

    Adenovirus isolate NADC-1, a strain of porcine adenovirus type 4, has a fiber containing an N-terminal virus attachment region, shaft and head domains, and a C-terminal galectin domain connected to the head by an RGD-containing sequence. The crystal structure of the head domain is similar to previously solved adenovirus fiber head domains, but specific residues for binding the coxsackievirus and adenovirus receptor (CAR), CD46, or sialic acid are not conserved. The structure of the galectin domain reveals an interaction interface between its two carbohydrate recognition domains, locating both sugar binding sites face to face. Sequence evidence suggests other tandem-repeat galectins have the same arrangement. We show that the galectin domain binds carbohydrates containing lactose and N-acetyl-lactosamine units, and we present structures of the galectin domain with lactose, N-acetyl-lactosamine, 3-aminopropyl-lacto-N-neotetraose, and 2-aminoethyl-tri(N-acetyl-lactosamine), confirming the domain as a bona fide galectin domain. PMID:20686025

  6. Structural characterization of the UL25 DNA-packaging protein from herpes simplex virus type 1.

    Science.gov (United States)

    Bowman, Brian R; Welschhans, Robert L; Jayaram, Hariharan; Stow, Nigel D; Preston, Valerie G; Quiocho, Florante A

    2006-03-01

    Herpesviruses replicate their double stranded DNA genomes as high-molecular-weight concatemers which are subsequently cleaved into unit-length genomes by a complex mechanism that is tightly coupled to DNA insertion into a preformed capsid structure, the procapsid. The herpes simplex virus type 1 UL25 protein is incorporated into the capsid during DNA packaging, and previous studies of a null mutant have demonstrated that its function is essential at the late stages of the head-filling process, either to allow packaging to proceed to completion or for retention of the viral genome within the capsid. We have expressed and purified an N-terminally truncated form of the 580-residue UL25 protein and have determined the crystallographic structure of the region corresponding to amino acids 134 to 580 at 2.1-Angstroms resolution. This structure, the first for any herpesvirus protein involved in processing and packaging of viral DNA, reveals a novel fold, a distinctive electrostatic distribution, and a unique "flexible" architecture in which numerous flexible loops emanate from a stable core. Evolutionary trace analysis of UL25 and its homologues in other herpesviruses was used to locate potentially important amino acids on the surface of the protein, leading to the identification of four putative docking regions for protein partners. PMID:16474137

  7. Single crystal and magnetic structures of maricite-type AgMnVO4

    Science.gov (United States)

    Ben Yahia, Hamdi; Shikano, Masahiro; Gaudin, Etienne; Avdeev, Maxim; Ling, Chris D.

    2015-01-01

    Single crystals of the ternary manganese vanadate AgMnVO4, were grown using AgVO3 flux. The structure was determined from single crystal X-ray diffraction data. The magnetic structure and properties of AgMnVO4 were characterized by magnetic susceptibility, specific heat, and low-temperature neutron powder diffraction measurements. AgMnVO4 crystallizes in the maricite-type structure with space group Pnma, a=9.5393(12), b=6.8132(9), c=5.3315(7) Å and Z=4. AgMnVO4 contains MnO4 chains made up of edge-sharing MnO6 octahedra, and these chains are interlinked by the VO4 and AgO4 tetrahedra. The specific heat measurements indicate a 3D-antiferromagnetic ordering at ~12.1 K and the neutron powder diffraction measurements at 5 K show that the Mn2+magnetic moments are antiferromagnetically coupled within the chains which are antiferromagnetically coupled to each other.

  8. 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

  9. STRUCTURAL PERFORMANCE OF TWO TYPES OF WALL SLAB CONNECTION UNDER OUT-OF-PLANE LATERAL CYCLIC LOADING

    OpenAIRE

    AHMED ABDULRAZZAQ NASSER AL-AGHBARI; SITI HAWA HAMZAH; NOR HAYATI ABDUL HAMID; NURHANIZA ABDUL RAHMAN

    2012-01-01

    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 h...

  10. 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.

  11. Four types of interference competition and their impacts on the ecology and evolution of size-structured populations and communities

    DEFF Research Database (Denmark)

    Zhang, Lai; Andersen, Ken Haste

    2015-01-01

    We investigate how four types of interference competition - which alternatively affect foraging, metabolism, survival, and reproduction - impact the ecology and evolution of size-structured populations. Even though all four types of interference competition reduce population biomass, interference competition at intermediate intensity sometimes significantly increases the abundance of adult individuals and the population[U+05F3]s reproduction rate. We find that foraging and metabolic interference evolutionarily favor smaller maturation size when interference is weak and larger maturation size when interference is strong. The evolutionary response to survival interference and reproductive interference is always larger maturation size. We also investigate how the four types of interference competition impact the evolutionary dynamics and resultant diversity and trophic structure of size-structured communities. Like other types of trait-mediated competition, all four types of interference competition can induce disruptive selection and thus promote initial diversification. Even though foraging interference and reproductive interference are more potent in promoting initial diversification, they catalyze the formation of diverse communities with complex trophic structure only at high levels of interference intensity. By contrast, survival interference does so already at intermediate levels, while reproductive interference can only support relatively smaller communities with simpler trophic structure. Taken together, our results show how the type and intensity of interference competition jointly affect coexistence patterns in structured population models

  12. Simultaneous type I and type II ?erenkov-phase matched second-harmonic generation in disordered nonlinear photonic structures.

    Science.gov (United States)

    Ayoub, Mousa; Paßlick, Markus; Imbrock, Jörg; Denz, Cornelia

    2015-11-01

    We observe simultaneous type I and II ?erenkov-phase matched second-harmonic generation in a disordered nonlinear photonic crystal. The mean width of the disordered ferroelectric domains and the laser beam width are adjusted to be on the same length scale. We analyze the polarization properties, emission angles and intensities of each process. PMID:26561107

  13. Preparation and crystal structure of the Er1Si2-x(vacancy)x compound, derivative of the AlB2 type structure

    International Nuclear Information System (INIS)

    The rare earth silicides are of great interest in applications to semiconductor technolgy and form the subject of studies aiming at a better understanding of their physical properties in relation with their structure and composition. A systematic study of the RSi2-x compounds, which crystallize in three main structure types ThSi2, GdSi2, AlB2 led us to find an orthorhombic superstructure of the hexagonal ErSi2-x (AlB2-type) structure. This superstructure is caused by a particular arrangement of the vacancies in the silicon sub-lattice

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

    Energy Technology Data Exchange (ETDEWEB)

    Barta, Michael L.; Zhang, Lingling; Picking, Wendy L.; Geisbrecht, Brian V. (UMKC); (OKLU)

    2010-10-05

    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. In this study, we present the 3.3 {angstrom} 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 (IpgC{sup 1-151}). 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 IpgC{sup 1-151}. 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.

  15. 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.

  16. Crystal structure of distorted fluorite-type SrU2O6 with pentavalent uranium

    International Nuclear Information System (INIS)

    Electron paramagnetic resonance absorption (EPR) of SrU2O6, in which the strontium and uranium atoms randomly occupy the metal sites of the fluorite-type crystal, showed a slightly anisotropic signal. In relation with this anomalous signal, the crystal structure of SrU2O6 has been analyzed by powder X-ray diffraction and Rietveld refinement. The sample has been found to consist of two phases with 73% and 27% in mass percent. The major phase crystallized in nearly cubic symmetry with slight rhombohedral distortion (a=3.8642 A and ?=60.096 ), whereas the other showed a significant rhombohedral distortion from cubic symmetry, i.e. a=3.8334 A and ?=62.024 . Consequently, the existence of these two phases has been considered to be one of the possible origins which introduce the observed anisotropic signal of EPR. (orig.)

  17. 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

  18. Topology of large-scale structure by galaxy type hydrodynamic simulations

    CERN Document Server

    Gott, J R; Ostriker, J P; Gott, J Richard; Cen, Renyue; Ostriker, Jeremiah P

    1995-01-01

    The topology of large scale structure is studied as a function of galaxy type using the genus statistic. In hydrodynamical cosmological CDM simulations, galaxies form on caustic surfaces (Zeldovich pancakes) then slowly drain onto filaments and clusters. The earliest forming galaxies in the simulations (defined as ``ellipticals") are thus seen at the present epoch preferentially in clusters (tending toward a meatball topology), while the latest forming galaxies (defined as ``spirals") are seen currently in a spongelike topology. The topology is measured by the genus (= number of ``donut" holes - number of isolated regions) of the smoothed density-contour surfaces. The measured genus curve for all galaxies as a function of density obeys approximately the theoretical curve expected for random-phase initial conditions, but the early forming elliptical galaxies show a shift toward a meatball topology relative to the late forming spirals. Simulations using standard biasing schemes fail to show such an effect. Larg...

  19. Subsonic structure of radiatively driven winds of early-type stars

    International Nuclear Information System (INIS)

    Methods are developed for the calculation of extended nongray model atmospheres for early-type stars with radiatively driven mass loss. Models for a central star of a planetary nebula and a Wolf-Rayet star are calculated, and compared with hydrostatic model calculations. Scaling laws are given for explaining the differences and similarities of stars of different stellar mass. It is found that transonic flow cannot occur if only continuum sources of opacity are present, because a moderate outward increase of the flux mean opacity is required for a physically acceptable structure. Observations of the Of star zeta Pup and the Wolf-Rayet star HD 50896 are summarized that indicate the continuum formation regions are spatially extended

  20. Fine structure of the type 2 solar radio burst on May 3, 1973

    International Nuclear Information System (INIS)

    The fluctuations of the type 2 radio emission on May 3, 1973 are analyzed from the data of the Weissenau spectrograph in the range from 30 to 960 MHz and the IZMIRAN polarimeter at 74 MHz. The characteristic time scale of the fluctuations at 74 MHz decreases during the event from 2-5 to 1-3 s. It is shown that the origin of the fluctuations is associated with the presence of inhomogeneities of the magnetic field and electron density in the corona. Those are structures strongly stretched along the surface of the Sun. Their radial sizes are not equal to (2-7)x108 cm and increase with distance from the Sun. The transversal sizes of the inhomogeneities are more then 1010 cm

  1. Structure and stability of monazite- and zircon-type LaVO4 under hydrostatic pressure

    Science.gov (United States)

    Cheng, Xuerui; Guo, Dongjie; Feng, Shiquan; Yang, Kun; Wang, Yongqiang; Ren, Yufen; Song, Yang

    2015-11-01

    Pure monazite (m)- and zircon (t)-type LaVO4 and LaVO4:Eu3+ were successfully synthesized by a hydrothermal method. The high pressure behavior of m- and t-LaVO4 nanoparticles has been investigated using Raman scattering techniques at room temperature. Raman measurements reveal a slight change for m-LaVO4 at 11.2 GPa because of an isostructural phase transition. However, striking changes in Raman spectra indicate a pressure-induced irreversible phase transition from the zircon to monazite structure for t-LaVO4 at around 5.9 GPa. The evolution of the luminescence spectra of t-LaVO4:Eu3+ has also been studied during the pressure-induced phase transition. It is observed that pressure has a great influence on the fluorescence intensity and the energy levels, which allows a more in-depth understanding of the nature of the pressure-induced phase transition for t-LaVO4. This result further confirms the conclusion that zircon-type RVO4 compounds with larger rare-earth cations will experience zircon to monazite phase transition.

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

    International Nuclear Information System (INIS)

    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. - Highlights: • Ce3+ substituted Ba hexaferrites. • Increased coercivity with Ce3+ substitution. • Decrease in saturation magnetization and Curie temperature

  3. Efficiency of different forest types in carbon storage depends on their internal structure

    Directory of Open Access Journals (Sweden)

    Iuliana F. Gheorghe

    2011-04-01

    Full Text Available Forest vegetation is a key factor in the maintenance of global carbon cycle balance under the present climate change conditions. Forest ecosystems are both buffers against extreme climatic events accompanying climate change and carbon sinks diminishing the environmental impact of anthropogenic greenhouse gas emissions. We investigated the influence of stand structure and site characteristics on the productivity and carbon storage capacity of temperate forest types. Predictors of species productivity were parameters such as stand density, age, height, average diameter and wood density. Morus alba (L. was more productive than average both in terms of annual volume increment and annual biomass gain, while Quercus sessiliflora (Matt. Lieb. and Quercus frainetto (Ten. were significantly less productive than average. Differences in stand productivity were explained by stand density, age, height, altitude, type of regeneration and species composition. Statistically significant differences were measured between the productivity of stands dominated by different woody species, with low productive stands dominated by slow growing species with high wood density like Quercus or Fagus, and highly productive stands rich in fast growing species with low wood density like Populus or Salix. Stands with different plant communities in the underlying herbaceous layer also tended to have different levels of productivity.

  4. Role of synthesis parameters on structural and electrical properties of M-type hexa-ferrites

    International Nuclear Information System (INIS)

    Phase purity, particle size and its distribution contributes a lot to the physical properties of M-type hexa-ferrites. These parameters are strongly influenced by the variation in synthesis parameters. In the present work, effect of synthesis parameters such as molar ratio (Fe/Sr) and volume rate of addition of precipitating agent on M-type hexa-ferrite (SrFe/sub 12/O/sub 19/) prepared by co-precipitation method have been investigated systematically. The molar ratio (Fe/Sr) in SrFe/sub 12/O/sub 19/ was varied as 12, 11, 10, 09, and 08. X-ray diffraction analysis revealed that molar ratio does not affect the phase purity. X-ray diffraction analysis of the samples prepared with different volume rate of addition of precipitating agent indicated that phase purity and micro-structural properties of SrFe/sub 12/O/sub 19/ are greatly influenced by the above synthesis parameter. High volume rate of addition of precipitating agent resulted in high phase purity, smaller particle size, and narrow particle size distribution. (author)

  5. 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 ? < 1?mm). We achieved various microscale patterns such as straight lines, zigzag lines, wavy lines and alphabetic words with a minimum width of 70?µm on the surface of the rod. Also, four pairs of line patterns were printed on the single rod for electrical interconnection. Printed patterns on the surface of the rod were used as electrodes for the 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.

  6. 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...

  7. 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...

  8. 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 l...

  9. 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)

  10. 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)

  11. Low-dark current structures for long-wavelength Type-II strained layer superlattice photodiodes

    Science.gov (United States)

    Tian, Zhaobing; DeCuir, Eric A.; Wijewarnasuriya, Priyalal S.; Pattison, James W.; Gautam, Nutan; Krishna, Sanjay; Dhar, Nibir; Welser, Roger E.; Sood, Ashok K.

    2013-06-01

    This paper describes our efforts on the development of low dark current long-wave infrared (LWIR) photodetectors based on type-II InAs/GaSb strained superlattices. By adopting a so-called pBiBn structure, a hybrid between the conventional PIN structure and unipolar barrier concepts, suppressed dark current and near-zero-bias operation are obtained, respectively. The LWIR photodetector has a dark current density as low as 1.42×10-5 A/cm2 at -60 mV, and R0A of 5365 ?cm2 at 76 K. The measured peak detectivity at 10.2 µm of 8.7×1010 cmHz1/2W-1 is obtained at -60 mV at 76 K. To further improve the device performances, a newer design with longer cut-off wavelength targeted for near zero-bias was also realized. This 2-µm-thick device exhibits a quantum efficiency of 20% at 10 µm under zero-bias.

  12. 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 ????? ?????????? ????????? ????????????? ???????.

  13. Prodrome of Paranoid Schizophrenia with Episodic Type of Course and Schizoaffective Structure of Manifest Episode

    Directory of Open Access Journals (Sweden)

    Alexander S. Bobrov

    2014-06-01

    Full Text Available Prodrome of paranoid schizophrenia with the episodic type of course (F20.1 and F20.2 according to ICD-10 and the schizoaffective structure of the episode was retrospectively studied. The pronounced and persistent affect, in particular depression in conjunction with hallucinations and/or delusions throughout the whole episode, served as the basis for an episode qualification as the schizoaffective structure. Diagnosis of schizophrenia was confirmed by the extremely low socio-demographic indicators at the time of the manifest episode, by the presence of catatonic or catatono-oneiroid symptoms in more than half of the patients, as well as an incongruence of hallucination plot and/or delusions against the dominant affect. In most cases, the affective symptoms were detected in clinical presentation of a prodrome and significantly more often in the form of depression, in comparison with bipolar and mixed affective disorders. Different clinical manifestations of negative symptoms were revealed in significantly more than half of the patients. The study showed that there is a significant frequency of negative manifestations in conjugation with depression in the prodrome.

  14. Protein delivery using nanoparticles based on microemulsions with different structure-types.

    Science.gov (United States)

    Graf, Anja; Jack, Kevin S; Whittaker, Andrew K; Hook, Sarah M; Rades, Thomas

    2008-04-23

    Poly(alkylcyanoacrylate) nanoparticles based on microemulsions with different structure-types and containing insulin as a model protein were prepared and characterised in this study. A phase diagram of the pseudoternary system isopropyl myristate, caprylocaproyl macrogolglycerides, polyglycerol oleate and water was established. All compounds used in this study were pharmaceutically acceptable and biocompatible. The area in the phase diagram containing optically isotropic, monophasic systems was designated as the microemulsion region. Systems within this region were identified as water-in-oil (w/o), bicontinuous and oil-in-water (o/w) microemulsions with viscosity, conductivity, differential scanning calorimetry and self-diffusion NMR. The size distributions of the resulting nanoparticles prepared by interfacial polymerisation from selected microemulsions using ethyl (2) cyanoacrylate and butyl (2) cyanoacrylate were unimodal but template- and monomer-dependent and ranged from 160 to 400 nm. Entrapment and release of insulin were also studied. Entrapment ranged from 11.5 to 20.9% and a near zero-order release was observed after an initial burst. Release of insulin was monitored for 6h. Insulin-loaded nanoparticles were 320-350 nm in size. The microemulsion-structure was retained during the polymerisation process as determined by NMR. This study showed that these microemulsions with flexible formulation possibilities for the solubilisation of peptides and proteins depending on their microstructure could serve well as a platform for designing encapsulation processes for oral delivery of insulin. PMID:18329862

  15. Fast Solid-State Li Ion Conducting Garnet-Type Structure Metal Oxides for Energy Storage.

    Science.gov (United States)

    Thangadurai, Venkataraman; Pinzaru, Dana; Narayanan, Sumaletha; Baral, Ashok Kumar

    2015-01-15

    Lithium ion batteries are the most promising energy storage system on the market today; however, safety issues associated with the use of flammable organic polymer-based electrolytes with poor electrochemical and chemical stabilities prevent this technology from reaching maturity. Solid lithium ion electrolytes (SLIEs) are being considered as potential replacements for the organic electrolytes to develop all-solid-state Li ion batteries. Out of the recently discovered SLIEs, the garnet-related structured Li-stuffed metal oxides are the most promising electrolytes due to their high total (bulk + grain boundary) Li ion conductivity, high electrochemical stability window (?6 V versus Li(+)/Li at room temperature), and chemical stability against reaction with an elemental Li anode and high-voltage metal oxide Li cathodes. This Perspective discusses the structural-chemical composition-ionic conductivity relationship of Li-stuffed garnets, followed by a discussion on the Li ion conduction mechanism, as well as the electrochemical and chemical stability of these materials. The performance of a number of all-solid-state batteries employing garnet-type Li ion electrolytes is also discussed. PMID:26263465

  16. A COMPARISON OF TWO THERMAL INSULATION AND STRUCTURAL MATERIALS FOR USE IN TYPE B PACKAGINGS

    Energy Technology Data Exchange (ETDEWEB)

    Blanton, P.; Eberl, K.

    2010-07-16

    This paper presents the summary of design features and test results of two Type B Shipping Package prototype configurations comprising different insulating materials developed by the Savannah River National Laboratory (SRNL) for the Department of Energy. The materials evaluated, a closed-cell polyurethane foam and a vacuformed ceramic fiber material, were selected to provide adequate structural protection to the package containment vessel during Normal Conditions of Transport (NCT) and Hypothetical Accident Condition (HAC) events and to provide thermal protection during the HAC fire. Polyurethane foam has been used in shipping package designs for many years because of the stiffness it provides to the structure and because of the thermal protection it provides during fire scenarios. This comparison describes how ceramic fiber material offers an alternative to the polyurethane foam in a specific overpack design. Because of the high operating temperature ({approx}2,300 F) of the ceramic material, it allows for contents with higher heat loads to be shipped than is possible with polyurethane foam. Methods of manufacturing and design considerations using the two materials will be addressed.

  17. Clathrate structure-type recognition: Application to hydrate nucleation and crystallisation

    Science.gov (United States)

    Lauricella, Marco; Meloni, Simone; Liang, Shuai; English, Niall J.; Kusalik, Peter G.; Ciccotti, Giovanni

    2015-06-01

    For clathrate-hydrate polymorphic structure-type (sI versus sII), geometric recognition criteria have been developed and validated. These are applied to the study of the rich interplay and development of both sI and sII motifs in a variety of hydrate-nucleation events for methane and H2S hydrate studied by direct and enhanced-sampling molecular dynamics (MD) simulations. In the case of nucleation of methane hydrate from enhanced-sampling simulation, we notice that already at the transition state, ˜80% of the enclathrated CH4 molecules are contained in a well-structured (sII) clathrate-like crystallite. For direct MD simulation of nucleation of H2S hydrate, some sI/sII polymorphic diversity was encountered, and it was found that a realistic dissipation of the nucleation energy (in view of non-equilibrium relaxation to either microcanonical (NVE) or isothermal-isobaric (NPT) distributions) is important to determine the relative propensity to form sI versus sII motifs.

  18. Durability improvement assessment in different high strength bacterial structural concrete grades against different types of acids

    Indian Academy of Sciences (India)

    Ramin Andalib; M Zaimi Abd Majid; A Keyvanfar; Amirreza Talaiekhozan; Mohd Warid Hussin; A Shafaghat; Rosli Mohd Zin; Chew Tin Lee; Mohammad Ali Fulazzaky; Hasrul Haidar Ismail

    2014-12-01

    This paper provides an insight into a new biotechnological method based on calcite precipitation for achieving high strength bio-concrete durability. It is very clear that mineral precipitation has the potential to enhance construction material resistance towards degradation procedures. The appropriate microbial cell concentration (30 * 105 cells/ml) was introduced onto different structural concrete grades (40, 45 and 50 MPa) by mixing water. In order to study the durability of structural concrete against aggressive agents, specimens were immersed in different types of acids solution (5% H2SO4 and HCl) to compare their effects on 60th, 90th and 120th day. In general, sulphuric acid and hydrochloric acid are known to be the most aggressive natural threats from industrial waters which can penetrate concrete to transfer the soluble calcium salts away from the cement matrix. The experimental results demonstrated that bio-concrete has less weight and strength losses when compared to the ordinary Portland cement concrete without microorganism. It was also found that maximum compressive strength and weight loss occurred during H2SO4 acid immersion as compared to HCl immersion. The density and uniformity of bio-concrete were examined using ultrasonic pulse velocity (UPV) test. Microstructure chemical analysis was also quantified by energy dispersive spectrometer (EDS) to justify the durability improvement in bacterial concrete. It was observed that less sulphur and chloride were noticed in bacterial concrete against H2SO4 and HCl, respectively in comparison to the ordinary Portland cement concrete due to calcite deposition.

  19. 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)

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

    Energy Technology Data Exchange (ETDEWEB)

    Tcherdyntsev, V.V., E-mail: vvch08@yandex.ru [National University of Science and Technology “MISIS”, Moscow 119049 (Russian Federation); Aleev, A.A. [SSC RF Institute for Theoretical and Experimental Physics, Moscow 117218 (Russian Federation); Churyukanova, M.N.; Kaloshkin, S.D. [National University of Science and Technology “MISIS”, Moscow 119049 (Russian Federation); Medvedeva, E.V. [Institute of Electrophysics, Ural Branch, Russian Academy of Sciences, Yekaterinburg 620016 (Russian Federation); Korchuganova, O.A. [SSC RF Institute for Theoretical and Experimental Physics, Moscow 117218 (Russian Federation); Zhukova, V. [Dpto. de Fns. Mater., UPV/EHU, San Sebastian 20018 (Spain); Zhukov, A.P. [Dpto. de Fns. Mater., UPV/EHU, San Sebastian 20018 (Spain); IKERBASQUE, Basque Foundation for Science, 48011 Bilbao (Spain)

    2014-02-15

    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.

  1. Structural and Magnetic Properties of Type-M Barium Ferrite - Thermoplastic Natural Rubber Nano composites

    International Nuclear Information System (INIS)

    Structural and magnetic properties of type-M barium ferrite (BaFe12O19) nanoparticles (? 20 nm) embedded in non-magnetic thermoplastic natural rubber (TPNR) matrices were investigated. The TPNR matrices were prepared from high density polyethylene (HDPE) and natural rubber (NR) in the weight ratios of 80:20 and 60:40, respectively, with 10 wt % of NR in the form of liquid natural rubber (LNR) which act as a comparabilities. BaFe12O19 - filled nano composites with 2 - 12 wt % BaFe12O19 ferrite were prepared using a melt- blending technique. Magnetic hysteresis was measured using a vibrating sample magnetometer (VSM) in a maximum field of 10 kOe at room temperature (25 degree Celsius). The saturation magnetisation (MS), remanence (MR) and coercivity (Hc) were derived from the hysteresis loops. The results show that the structural and magnetic properties of nano composites depend on both the ferrite content and the composition of the natural rubber or plastic in the nano composites. All the nano composites exhibit an exchange bias-like phenomenon resulting from the exchange coupling of spins at the interface between the core ferrimagnetic region and the disordered surface region of the nanoparticles. (author)

  2. 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.

  3. A strategic analysis of the development of structural materials for proto-type reactors for fusion

    International Nuclear Information System (INIS)

    Structural Materials Research and Development Subcommittee of Nuclear Materials Committee in Japan Atomic Energy Research Institute had made a study to propose a strategy how to expedite the research and development of structural materials for fusion reactors. This study was carried out along with the interim report of the Development of Structural Materials in Fusion Reactors proposed by Planning and Promotion Subcommittee of Fusion Council as well as with the Third Phase Basic Program of Fusion Research and Development settled by the Atomic Energy Commission. The present report was published to publicize the results of analyses of this study. In this report we focused mostly on the development of structural materials of blankets for tritium breeding because it is considered to be the most difficult task in the materials development due to severe conditions imposing on the blankets. We selected three candidate materials, namely, reduced low activation ferritic/ martensitic steel, SiC/SiC composites and Vanadium alloys, and elucidate the conditions in which these materials would be used as well as the design requirements for each material. Based on these conditions and requirements, we described the present status and the key issues of each material. For the development of the structural materials for the blankets, the keenest issue is the improvement and evaluation of radiation integrity and stability. Therefore, the necessity of radiation facilities, especially accelerator-type neutron sources with near fusion energy spectra was described. In addition the usage of fission reactors as irradiation facilities was also emphasized. In the processing of this reviewing we categorized reduced low activation ferritic/martensitic steel as advanced material, and SiC/SiC composites and Vanadium alloys as next-generation advanced material from the present status of developmental maturity. A periodical check and review in order to take the future progress in the development of these materials into account will examine the appropriateness of the present categories of these materials. In Chapters 1 to 5 the summary of our subcommittee's study was described, and in Chapter 6 the details of the above three candidates and irradiation facilities. (author)

  4. Structural and electrochemical characterisation of [Pd(salen)]-type conducting polymer films

    Energy Technology Data Exchange (ETDEWEB)

    Fonseca, J. [REQUIMTE, Departamento de Quimica e Bioquimica, Faculdade de Ciencias, Universidade do Porto, Rua do Campo Alegre, 4169-007 Porto (Portugal); Tedim, J. [Department of Chemistry, University of Leicester, Leicester LE1 7 RH (United Kingdom); Biernacki, K.; Magalhaes, A.L. [REQUIMTE, Departamento de Quimica e Bioquimica, Faculdade de Ciencias, Universidade do Porto, Rua do Campo Alegre, 4169-007 Porto (Portugal); Gurman, S.J. [Department of Physics, University of Leicester, Leicester LE1 7 RH (United Kingdom); Freire, C., E-mail: acfreire@fc.up.p [REQUIMTE, Departamento de Quimica e Bioquimica, Faculdade de Ciencias, Universidade do Porto, Rua do Campo Alegre, 4169-007 Porto (Portugal); Hillman, A.R., E-mail: arh7@le.ac.u [Department of Chemistry, University of Leicester, Leicester LE1 7 RH (United Kingdom)

    2010-11-01

    The oxidative polymerisation of four structurally-related [Pd(salen)] complexes and characterisation of the resulting polymeric films by cyclic voltammetry (CV), UV-visible transmission spectroscopy, X-ray absorption spectroscopy (XAS) and X-ray photoelectron spectroscopy (XPS) is reported. The voltammetric technique gives insight into the electrochemical properties of the polymeric films whereas UV-visible spectroscopy is used to characterise the electronic structure of Pd electroactive films, of particular relevance to the type of charge carriers. X-ray techniques (supported by density functional theory, DFT) provide information related to composition and structural features of [Pd(salen)] precursors and the resulting polymers. Characterisation of poly[Pd(salen)] films shows that the electrochemical response of these supramolecular systems is ligand-based and dependent upon substituents in the diimine bridge and aldehyde moieties. XAS measurements near the Pd K-edge demonstrate that polymerisation of the Pd complexes does not change the coordination sphere of the Pd centre; this is consistent with the coupling of monomers units via phenyl rings. As further evidence of ligand-based electrochemical responses, polymer doping does not impart any changes at the Pd centre or its coordination sphere. Compositional analysis by XPS confirms that C: Pd, N: Pd and O: Pd surface atomic ratios do not change significantly from monomer to undoped or doped polymer, except for small variations associated with incorporation of electrolyte and solvent upon polymerisation and polymer oxidation. Overall, the data provide a picture of a polyaromatic delocalised electroactive system, in which the metal atom plays a templating (rather than electroactive) role.

  5. Structural and electrochemical characterisation of [Pd(salen)]-type conducting polymer films

    International Nuclear Information System (INIS)

    The oxidative polymerisation of four structurally-related [Pd(salen)] complexes and characterisation of the resulting polymeric films by cyclic voltammetry (CV), UV-visible transmission spectroscopy, X-ray absorption spectroscopy (XAS) and X-ray photoelectron spectroscopy (XPS) is reported. The voltammetric technique gives insight into the electrochemical properties of the polymeric films whereas UV-visible spectroscopy is used to characterise the electronic structure of Pd electroactive films, of particular relevance to the type of charge carriers. X-ray techniques (supported by density functional theory, DFT) provide information related to composition and structural features of [Pd(salen)] precursors and the resulting polymers. Characterisation of poly[Pd(salen)] films shows that the electrochemical response of these supramolecular systems is ligand-based and dependent upon substituents in the diimine bridge and aldehyde moieties. XAS measurements near the Pd K-edge demonstrate that polymerisation of the Pd complexes does not change the coordination sphere of the Pd centre; this is consistent with the coupling of monomers units via phenyl rings. As further evidence of ligand-based electrochemical responses, polymer doping does not impart any changes at the Pd centre or its coordination sphere. Compositional analysis by XPS confirms that C: Pd, N: Pd and O: Pd surface atomic ratios do not change significantly from monomer to undoped or doped polymer, except for small variations associated with incorporation of electrolyte and solvent upon polymerisation and polymer oxidation. Overall, the data provide a picture of a polyaromatic delocalised electroactive system, in which the metal atom plays a templating (rather than electroactive) role.

  6. Itinerant type many-body theories for photo-induced structural phase transitions

    Science.gov (United States)

    Nasu, Keiichiro

    2004-09-01

    Itinerant type quantum many-body theories for photo-induced structural phase transitions (PSPTs) are reviewed in close connection with various recent experimental results related to this new optical phenomenon. There are two key concepts: the hidden multi-stability of the ground state, and the proliferations of optically excited states. Taking the ionic (I) rarr neutral (N) phase transition in the organic charge transfer (CT) crystal, TTF-CA, as a typical example for this type of transition, we, at first, theoretically show an adiabatic path which starts from CT excitons in the I-phase, but finally reaches an N-domain with a macroscopic size. In connection with this I-N transition, the concept of the initial condition sensitivity is also developed so as to clarify experimentally observed nonlinear characteristics of this material. In the next, using a more simplified model for the many-exciton system, we theoretically study the early time quantum dynamics of the exciton proliferation, which finally results in the formation of a domain with a large number of excitons. For this purpose, we derive a stepwise iterative equation to describe the exciton proliferation, and clarify the origin of the initial condition sensitivity. Possible differences between a photo-induced nonequilibrium phase and an equilibrium phase at high temperatures are also clarified from general and conceptional points of view, in connection with recent experiments on the photo-induced phase transition in an organo-metallic complex crystal. It will be shown that the photo-induced phase can make a new interaction appear as a broken symmetry only in this phase, even when this interaction is almost completely hidden in all the equilibrium phases, such as the ground state and other high-temperature phases. The relation between the photo-induced nonequilibrium phase and the hysteresis induced nonequilibrium one is also qualitatively discussed. We will be concerned with a macroscopic parity violation and a ferro- (or super-para-) electricity, induced by a photogenerated electron in the perovskite type quantum dielectric SrTiO3. The photogenerated electron in the 3d band of Ti is assumed to couple weakly, but quadratically, with soft-anharmonic T1u phonons, and strongly but linearly to the breathing (A1g) type high energy phonons. These two types of electron-phonon coupling result in two types of polarons, a super-para-electric (SPE) large polaron with a quasi-global parity violation, and an off-centre type self-trapped polaron with only a local parity violation. This SPE large polaron, being equal to a charged and conductive ferroelectric domain, greatly enhances both the quasi-static electric susceptibility and the electronic conductivity. We also briefly review recent successes to observe the PSPTs more directly by using x-ray measurements.

  7. 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 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 attain an economic improvement of a large s

  8. Insight into the secondary structure of chloramphenicol acetyltransferase type I — computer analysis and FT-IR spectroscopic characterization of the protein structure

    Science.gov (United States)

    Andreeva, A. E.; Karamancheva, I. R.

    2001-05-01

    The secondary structure of chloramphenicol O-acetyltransferase type I (CAT I) and an N-terminal deleted mutant has been studied by Fourier transform infrared spectroscopy. The analysis of the amide I band of different samples (KBr, hydrated films and buffer solution) by Fourier self-deconvolution followed by a curve fitting was performed. The spectroscopic data have been utilized to determine the ?-helix and ?-structure % contents, which depend strongly on the protein sample preparation. Furthermore, the secondary structure of the enzyme-inhibitor Crystal Violet complex was analyzed. The observed difference in the secondary structural contents suggests that some conformational changes of the enzyme are induced by the inhibitor after binding.

  9. Equilibrium structures of Type 304 and Type 316 stainless steel in the temperature range 800/sup 0/F to 1500/sup 0/F: a metallographic review

    Energy Technology Data Exchange (ETDEWEB)

    Bagnall, C.; Shiels, S.A.

    1976-01-01

    The phase diagrams depicted in this report serve as a general guide to the structures that may be found in Type 304 and Type 316 stainless steels as thermodynamic equilibrium is approached. The influences of cold work and stress, however, are not indicated but will tend to cause reactions to proceed more rapidly or to take place where they are not normally favored. A large change in grain size from those shown (ASTM 8-9), will also have an effect on the distribution of the second phases. The proposed mechanism for sigma formation in Type 304 SS requires substantiation with additional experimental evidence over the 1100-1500/sup 0/F temperature range using material containing carbon up to the H-grade level of 1000 ppM.

  10. Synthesis and crystal structures of novel LaOAgS-type alkaline earth – Zinc, manganese, and cadmium fluoride pnictides

    International Nuclear Information System (INIS)

    Highlights: • Sight new alkaline earth – Mn, Zn, Cd fluoride pnictides were prepared. • All new compounds adopt the LaOAgS structure type. • Bond distances in their structures are transferable within 2–3%. • Very close similarities are observed in structural chemistry of LaOAgS- and HfCuSi2-type compounds of Mn, Cu, Zn, Ag, and Cd. -- Abstract: Systematic studies of the LaOAgS-type compounds among alkaline earth – Zn/Cd/Mn fluoride pnictides revealed the existence of new representatives SrFMnP, SrFMnAs, SrFMnSb, SrFZnAs, SrFZnSb, BaFZnAs, BaFCdP, and BaFCdAs. Similar to rare-earth oxide compounds and contrary to isolobal chalcogenides of Cu/Ag, not all possible compositions could be realized. No compound of the structure type is formed for calcium; strontium forms fluoride pnictides only with zinc and manganese, while for barium, new representatives are also formed with cadmium. This trend, which possibly has a geometrical origin, is corroborated by quantum chemical calculations. Formation of NdOZnP-type compounds also was not observed suggesting the structure to be characteristic only for rare earth – zinc oxide phosphides

  11. Synthesis and crystal structures of novel LaOAgS-type alkaline earth – Zinc, manganese, and cadmium fluoride pnictides

    Energy Technology Data Exchange (ETDEWEB)

    Charkin, Dmitri O., E-mail: charkin@inorg.chem.msu.ru; Urmanov, Arthur V.; Plokhikh, Igor V.; Korshunov, Alexander D.; Kuznetsov, Alexey N.; Kazakov, Sergey M.

    2014-02-05

    Highlights: • Sight new alkaline earth – Mn, Zn, Cd fluoride pnictides were prepared. • All new compounds adopt the LaOAgS structure type. • Bond distances in their structures are transferable within 2–3%. • Very close similarities are observed in structural chemistry of LaOAgS- and HfCuSi{sub 2}-type compounds of Mn, Cu, Zn, Ag, and Cd. -- Abstract: Systematic studies of the LaOAgS-type compounds among alkaline earth – Zn/Cd/Mn fluoride pnictides revealed the existence of new representatives SrFMnP, SrFMnAs, SrFMnSb, SrFZnAs, SrFZnSb, BaFZnAs, BaFCdP, and BaFCdAs. Similar to rare-earth oxide compounds and contrary to isolobal chalcogenides of Cu/Ag, not all possible compositions could be realized. No compound of the structure type is formed for calcium; strontium forms fluoride pnictides only with zinc and manganese, while for barium, new representatives are also formed with cadmium. This trend, which possibly has a geometrical origin, is corroborated by quantum chemical calculations. Formation of NdOZnP-type compounds also was not observed suggesting the structure to be characteristic only for rare earth – zinc oxide phosphides.

  12. [Effect of operational modes on community structure of type I methanotroph in the cover soil of municipal solid waste landfill].

    Science.gov (United States)

    Yu, Ting; He, Pin-Jing; Lü, Fan; Shao, Li-Ming

    2008-10-01

    Type I methanotroph is crucial for methane oxidization and it responses fast to the changes in environment. In this study, 16S rDNA-based denaturing gradient gel electrophoresis (DGGE) gene fingerprint technology was applied to investigate the effect of operational modes, i. e. high-density polyethylene liner (HDPE) isolation or subsurface irrigation of landfill leachate and vegetation, on community structure and diversity of type I methanotroph in soils covering municipal solid waste landfill. 16S rDNA based phylogenetic analysis reveals type I methanotroph in all tested soils belongs to Methylobacter. According to Shannon-Wiener diversity index and principal component analysis, landfill leachate subsurface irrigation and vegetation have more impact on type I methanotroph community structure and diversity than HDPE liner isolation does, and they reduce type I methanotroph diversity. Leachate irrigation is supposed to inhibit the growth of Methylobacter population. Community structure of type I methanotroph in landfill cover soil isolated by HDPE, i.e. invaded by landfill gas, shifts during long-term gas interference. When cover age is 1.5 years old, Shannon-Wiener diversity index of type I methanotroph reaches its maximum. PMID:19143406

  13. 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

  14. 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.

  15. Biocompatible microemulsions of dicephalic aldonamide-type surfactants: formulation, structure and temperature influence.

    Science.gov (United States)

    Wilk, Kazimiera A; Zieli?ska, Katarzyna; Hamerska-Dudra, Agnieszka; Jezierski, Adam

    2009-06-01

    The temperature effects upon microemulsion systems composed of dicephalic N-dodecyl-N,N-bis[(3-D-aldonylamido)propyl]amines C12-DX (gluconyl GA or lactobionyl LA)/iso-butanol/hydrophilic (diethylene glycol monoethyl ether) or hydrophobic (iso-octane) oils/water were investigated by evaluating isotropic area magnitudes in the pseudoternary phase diagrams, as well as droplet characteristics by electron paramagnetic resonance (EPR) and dynamic light scattering (DLS) spectroscopies at 25, 40 and 55 degrees C. We concluded that in the examined systems a cosurfactant, such as middle-chain alcohol, was needed to obtain large mesophase isotropic areas. The phase behavior and structure of the examined systems were temperature insensitive but they were intimately determined by the nature of the C12-DX and the polarity of the oil phase. By adjusting the nature of the oil, as well as the surfactant hydrophilicity, the performed isotropic systems containing low amounts of nonaggressive surfactant could be formulated successfully. Interfacial properties and the dynamic structure of the surfactant/cosurfactant monolayer were studied by the spin probe technique using the 16-doxylstearic acid methyl ester (16-DSE) as the appropriate probe. The polarity of the interface was not affected by temperature but the interface rigidity was dependent upon the nature of the surfactant and oil as well as on temperature. The size of the dispersed domains, evaluated by dynamic light scattering (DLS), was found to be a function of temperature, surfactant content and type of additives. The investigated o/w microemulsions (i.e., ranging from 3.0 to 8.8 nm) constituted promising templates for a variety of syntheses of nanostructures with small size and high-capacity solubilizing media. PMID:19383561

  16. Local structure of Cu in Cs8Na16Cu5Ge131 type II clathrate

    International Nuclear Information System (INIS)

    We have used X-ray absorption spectroscopy (XAS) to investigate the local structure of Cu and Ge in the Cs8Na16Cu5Ge131 type II clathrate. We show that the local structure parameters for Ge (coordination number and distances) are consistent with those derived on the basis of XRD investigation of Cs8Na16Ge136. The EXAFS data suggest that Cu either randomly substitutes for Ge on the clathrate framework or preferentially on the 96g site but not preferentially on the 32e or 8a sites (Wyckoff notation). Furthermore, we find that the Cu-Ge distance is smaller than the Ge-Ge distance by 0.13 A, indicating a local distortion around the Cu atoms. The estimated degrees of disorder for Cu-Ge and Ge-Ge interactions indicate the Cu-Ge clathrate framework to be relatively stiff, while those for Na-Ge and Cs-Ge interactions corroborate previous observations of strong thermal disorder of the alkali guests in these materials. Our XAS results offer insight into the site substitution of Cu in this material, information unattainable from X-ray diffraction due to the lack of scattering contrast between Cu and Ge. - Graphical abstract: Comparison of Fourier transforms of Cu K-edge and Ge K-edge EXAFS spectra for Cs8Na16Cu5Ge131 collected near the temperature of liquid nitrogen (LN). The data clearly show that the Cu-Ge distance is smaller than the Ge-Ge distance, indicating the presence of a local distortion around Cu

  17. 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

  18. 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

  19. Structure and properties of rhombohedral CePd3Ga8: A variant of the cubic parent compound with BaHg11 structure type

    International Nuclear Information System (INIS)

    Single crystals of a new intermetallic gallide, R-CePd3Ga8, have been synthesized from excess molten gallium. Single-crystal X-ray diffraction reveals that R-CePd3Ga8 crystallizes in the R-3m space group with a=b=c=8.4903(10) Å and ?=?=?=89.993(17). R-CePd3Ga8 is a variant of the cubic BaHg11 structure type with three structural units: a Ce-centered polyhedron, a distorted cube of Pd2Ga6 and a Pd-centered cuboctahedron. The distortions of these units are compared to undistorted analogous units in intermetallic compounds with BaHg11 structure type. Field and temperature-dependent magnetization measurements on R-CePd3Ga8 reveal a paramagnetic material with strong antiferromagnetic correlations and a magnetization consistent with Ce3+. Electrical resistance measurements indicate Kondo behavior between localized Ce3+ magnetic moments. - Graphical Abstract: Single crystals of CePd3Ga8 have been synthesized from Ga flux. This new compound is the first rhombohedral variant of the cubic BaHg11 structure type. Highlights: ? Single crystals of CePd3Ga8 were synthesized from gallium flux. ? CePd3Ga8 is the first rhombohedral variant of the cubic BaHg11 structure type. ? Paramagnetic with antiferromagnetic correlations. ? Magnetization consistent with Ce3+.

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

    OpenAIRE

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

  1. Distributions of amino acids suggest that certain residue types more effectively determine protein secondary structure

    OpenAIRE

    Battelle, S. Saraswathi; Fernández-Martínez, J. L.; Koli?ski, A.; Jernigan, R. L.; Battelle, A. Kloczkowski

    2013-01-01

    Exponential growth in the number of available protein sequences is unmatched by the slower growth in the number of structures. As a result, the development of efficient and fast protein secondary structure prediction methods is essential for the broad comprehension of protein structures. Computational methods that can efficiently determine secondary structure can in turn facilitate protein tertiary structure prediction, since most methods rely initially on secondary structure predictions. Rec...

  2. Dust grains and the structure of steady C-type magnetohydrodynamic shock waves in molecular clouds

    CERN Document Server

    Wardle, M

    1998-01-01

    I examine the role of dust grains in determining the structure of steady, cold, oblique C-type shocks in dense molecular gas. Gas pressure, the inertia of the charged components, and changes in ionisation are neglected. The grain charge and rate coefficients for electron-neutral and grain-neutral elastic scattering are assumed constant at values appropriate to the shock interior. An MRN size distribution is accounted for by estimating an effective grain abundance and Hall parameter for single-size grains. A one-parameter family of intermediate shocks exists for each shock speed v_s between the intermediate signal speed v_A cos theta and sqrt{2} v_A cot theta, where v_A is the preshock Alfven speed and theta is the angle between the preshock magnetic field and the normal to the shock front. In addition, there is a unique fast shock for each v_s > v_A. If the preshock density n_H is greater than about 10^5 cm^-3 and the preshock magnetic field satisfies B(mG) less than about n_H(10^5 cm^-3) grains are partially...

  3. Synthesis, structure and applications of [cis-dioxomolybdenum(VI)-(ONO)] type complexes

    Indian Academy of Sciences (India)

    Rajan Deepan Chakravarthy; Dillip Kumar Chand

    2011-03-01

    Oxo-molybdenum chemistry is of great interest since such units are found in the active sites of a majority of molybdo-enzymes. In order to mimic the biological systems, a number of oxo-molybdenum complexes have been synthesised and studied. This review describes synthesis, structure and applications of oxomolybdenum complexes particularly cis-MoO2(L)(D) where L stands for a dianionic tridentate ONO ligand and D for a donor solvent molecule/monodentate ligand. The ligand moieties are derived from Schiff base, hydrazide Schiff base and other related tridentate ligands L(H)2. The coordination geometry around the Mo center in these complexes can be best described as a distorted octahedron in which the ONO-tridentate ligand occupies meridional position with two anionic oxygen donors mutually trans and are cis to the oxygen centers of the cis-dioxo group. Mostly the applications of cis-MoO2-(ONO) type complexes seen in literature are oxo transfer reactions like epoxidation, sulfoxidation and phosphine oxidation reactions.

  4. 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.

  5. 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.

  6. XAFS study on the structure of ytterbium(III) trifluoromethanesulfonates as a new type catalyst

    International Nuclear Information System (INIS)

    Yb L3-edge XAFS spectroscopy was applied to study on the local structure around Yb atoms in ytterbium(III) trifluoromethanesulfonates (Yb(OTf)3) catalysts dissolved in various solution and those in Yb(OTf)3 chiral catalysts prepared by a choice of two types of achiral ligands. XAFS analyses showed the difference in the coordination number of oxygen atoms between Yb(OTf)3 catalysts dissolved in aqueous and nonaqueous solutions, suggesting the activation of the Yb(OTf)3 catalyst by the hydration. For the two Yb(OTf)3 chiral catalysts, both the catalysts were found to be present as trivalent ytterbium oligomer. Curve-fitting analysis of EXAFS showed that the Yb-Yb distance of two catalyst complexes is fairly different from each other, i.e., one is 3.68 A and the other 4.04 A, which is expected to explain the difference of the catalytic performance of the two chiral catalysts. (author)

  7. 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

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

    Science.gov (United States)

    Shi, Guangsha; Kioupakis, Emmanouil

    2015-03-01

    We used density functional and many-body perturbation theory to calculate the band structure 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 calculated the electronic transport coefficients within the constant relaxation time approximation as a function of doping concentration and temperature for single-crystal and polycrystalline materials to understand experimental measurements. The electronic transport coefficients are highly anisotropic and are strongly affected by bipolar transport effects at low doping and high temperature. Our results indicate that SnSe exhibits optimal thermoelectric performance at high temperature when doped in the 1019-1020 cm-3 range. This work was supported in part by the National Science Foundation (DMR-1254314) and in part by CSTEC, an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science. Computational resources were provided by the DOE NERSC facility.

  9. 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

  10. 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.

  11. The structural and optical properties of type III human collagen biosynthetic corneal substitutes

    Science.gov (United States)

    Hayes, Sally; Lewis, Phillip; Islam, M. Mirazul; Doutch, James; Sorensen, Thomas; White, Tomas; Griffith, May; Meek, Keith M.

    2015-01-01

    The structural and optical properties of clinically biocompatible, cell-free hydrogels comprised of synthetically cross-linked and moulded recombinant human collagen type III (RHCIII) with and without the incorporation of 2-methacryloyloxyethyl phosphorylcholine (MPC) were assessed using transmission electron microscopy (TEM), X-ray scattering, spectroscopy and refractometry. These findings were examined alongside similarly obtained data from 21 human donor corneas. TEM demonstrated the presence of loosely bundled aggregates of fine collagen filaments within both RHCIII and RHCIII-MPC implants, which X-ray scattering showed to lack D-banding and be preferentially aligned in a uniaxial orientation throughout. This arrangement differs from the predominantly biaxial alignment of collagen fibrils that exists in the human cornea. By virtue of their high water content (90%), very fine collagen filaments (2–9 nm) and lack of cells, the collagen hydrogels were found to transmit almost all incident light in the visible spectrum. They also transmitted a large proportion of UV light compared to the cornea which acts as an effective UV filter. Patients implanted with these hydrogels should be cautious about UV exposure prior to regrowth of the epithelium and in-growth of corneal cells into the implants. PMID:26159106

  12. Depleted cores, multi-component fits, and structural parameter relations for luminous early-type galaxies

    CERN Document Server

    Dullo, Bililign T

    2013-01-01

    New surface brightness profiles from 26 early-type galaxies with partially depleted cores have been extracted from the full radial extent of Hubble Space Telescope images, giving us a total sample of 31 such core-Sersic galaxies. We have carefully quantified the radial stellar distributions of the elliptical galaxies using the core-Sersic model whereas for the lenticular galaxies a core-Sersic bulge plus an exponential disc model gives the best representation. We additionally caution about the excessive use of multiple Sersic functions for decomposing galaxies. The structural parameters obtained from our fitted models are used to update several `central' as well as `global' galaxy scaling relations. We find near-linear relations between the break radius R_b and the spheroid luminosity L such that R_b ~ L^(1.13 +/- 0.13), and with the supermassive black hole mass M_BH such that R_b ~ M_BH^(0.83+/- 0.21). This is internally consistent with the notion that major, dry mergers add the stellar and black hole mass i...

  13. 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...

  14. Atomic structure of radiation damage in FCC-metals after different types of irradiation

    International Nuclear Information System (INIS)

    Full text: Experimental data on atomic structure of radiation damage (individual point defects and their small complexes, as well as radiation clusters, formed in non-overlapping cascade areas) in pure platinum after different types of irradiation were obtained. The basic purpose consists in the analysis of structure of radiation damage formed during ion implantation (E = 20 keV), and under irradiation with fast (E > 0.1 MeV) neutrons. For study of the defect structure initiated by irradiation, the method of field ion microscopy (FIM) was used. The FIM method makes it possible to carry out direct precise investigation on an atomic scale of defects of crystal lattice of a material on an atom-pure surface, and of cascades which cause atom displacement. At the same time the method allows analyzing the object of research in volume by controlled and sequential removal of surface atoms by an electric field at cryogenic temperatures. The purpose of this work was experimental investigation of radiation clusters, formed in pure platinum (purity of 99.99 %) after neutron irradiation in reactor RWW-2M at temperature 310 K up to fast neutrons fluence (E > 0,1 MeV) 6.7·1021m-'2 and 3.5·1022m-'2. Ion implantation of accelerated Ar+ beams carried out on an installation with a plasma source of charged particles, generation of ions working in a continuous mode. In the crystal lattice of platinum irradiated up to fluence 6.7·1021m-'2, radiation damage has been found. The found defects presented, as a rule, either separate vacancies or small vacancy complexes with the sizes comparable with interatomic distances, or presented interstitials. The structure of defects was revealed by controlled and sequential removal of surface atoms by an electric field. As a result of irradiation of platinum up to fluence 3.5·1022m-'2, in this material by methods of FIM many radiation clusters initiated by interaction of accelerated neutrons with the substance were revealed. It is established that these damaged areas represent depleted zones containing separate vacancies, and also small vacancy complexes, with a 'belt' of interstitial atoms. Quantitative estimation of the sizes of such radiation defects was carried out and their density in volume was experimentally established. By method FIM it is established, that after neutron irradiation of platinum at temperature 310 K up to fluence 3.5·1022m-'2 clusters were formed in it of 3.2 nanometers average size, with concentration ? 9·1022m-'3, at average concentration of vacancies in clusters 9 %. In this work an attempt has been made to find out spatial geometry of the depleted zones in the platinum irradiated up to fluence of fast neutrons 3.5·1022m-'2. The exterior shape of zone was generally found to be highly irregular as vacancies making them are located extremely irregularly. In investigation of defect structure of platinum after irradiation with Ar+ ions specimens with an atom-smooth surface were exposed to ion implantation preliminarily certified in FIM. The atomic structure of radiation damage, both on the implanted surface and in the subsurface volume, after various dozes of irradiation, has been finally analysed. It is established, that there is a strong dependence of the size and density of radiation defects on their depth bedding in a material. Comparison of the atomic structure of the defects received after different types of irradiation in pure platinum is carried out. The research described in this paper was made possible by grant No. 03-02-16560-a from the Russian Foundation for Basic Research, the Program of State Support to Leading Scientific Schools of the Russian Federation (grant No. NSh-639.2003.2), and also with the support from the Urals Branch of the Russian Academy of Sciences (the grant for young scientists and post-graduate students). (author)

  15. 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, Thimoté; 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...

  16. Zr$_5$Sb$_3$$_-$$_x$Ru$_x$, a new superconductor in the W$_5$Si$_3$ structure type

    OpenAIRE

    Xie, Weiwei; Luo, Huixia; Phelan, Brendan F.; Cava, Robert. J.

    2015-01-01

    We report that at low Ru contents, up to x = 0.2, the Zr$_5$Sb$_3$$_-$$_x$Ru$_x$ solid solution forms in the hexagonal Mn$_5$Si$_3$ structure type of the host (x = 0), but that at higher Ru contents (x = 0.4 - 0.6) the solid solution transforms into the tetragonal W$_5$Si$_3$ structure type. We find that tetragonal Zr$_5$Sb$_2$$_.$$_4$Ru$_0$$_.$$_6$ is superconducting at 5 K, significantly higher than the transition temperature of hexagonal Zr$_5$Sb$_3$ (x = 0), which has a ...

  17. Structural models of the human copper P-type ATPases ATP7A and ATP7B

    DEFF Research Database (Denmark)

    Gourdon, Pontus Emanuel; Sitsel, Oleg; Karlsen, Jesper Lykkegaard; Moller, Lisbeth Birk; Nissen, Poul

    2012-01-01

    The human copper exporters ATP7A and ATP7B contain domains common to all P-type ATPases as well as class-specific features such as six sequential heavy-metal binding domains (HMBD1-HMBD6) and a type-specific constellation of transmembrane helices. Despite the medical significance of ATP7A and ATP7B related to Menkes and Wilson diseases, respectively, structural information has only been available for isolated, soluble domains. Here we present homology models based on the existing structures of s...

  18. Play types, structural history and distribution of Middle Buntsandstein gas fields in NW Germany. Observations and their genetic interpretation

    Energy Technology Data Exchange (ETDEWEB)

    Baerle, C.; Kuehn, M.; Sommer, J. [Wintershall Holding AG, Erdoelwerke Barnstorf (Germany); Clever, B. [Wintershall Noordzee B.V., Rijswijk (Netherlands); Karnin, W.D.; Gast, R.

    2008-10-23

    The Middle Buntsandstein is one of the most important gas reservoirs in the northwestern German area. So far, nearly 100 billion cubic meter gas could be proven in 26 gas fields. The authors of the contribution under consideration report on play type, structural history and distribution of Middle Buntsandstein gas fields in northwestern Germany. The Buntsandstein structures consist of a tectonic-halokinetic structural floor with the three types inversion play, late halogenetic play and early halogenetic play. The development of the Buntsandstein fields depends of the timing of the structural formation and the presence of migration windows. Beside classical migration windows in the Zechstein salina, the internal ranges of the Permian basin require an existence of disturbances which enable a migration of the carbon-generated gases by the second barrier.

  19. Structural, electronic and thermodynamic properties of BiF3-type Mg3Gd compound: A first-principle study

    Science.gov (United States)

    Liu, Yong; Hu, Wen-Cheng; Li, De-Jiang; Zeng, Xiao-Qin; Xu, Chun-Shui; Yang, Xiang-Jie

    2014-01-01

    First-principle calculations based on density functional theory are adopted to investigate the structural, electronic and thermodynamic properties of BiF3-type Mg3Gd compound. Our results for the equilibrium structural parameters are consistent with experimental values and other theoretical results. The single-crystal elastic constants, polycrystalline elastic moduli, Poisson's ratio and anisotropy factor are determined using the Voigt-Reuss-Hill approximation. Estimated Cauchy pressure and the G/B relationship indicate that Mg3Gd is mechanically stable and brittle. In addition, the electronic structure is studied within the generalized gradient approximation (GGA) and local spin density approximation (LSDA) along with Hubbard energy. The calculations associated with phonon properties confirm the dynamical stability of BiF3-type structure. Finally, the dependences of normalized volume, bulk modulus and thermodynamic properties of Mg3Gd are obtained via the quasi-harmonic Debye model.

  20. 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)

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

    Scientific Electronic Library Online (English)

    Ana Carolina Ferreira, Soares; Aline Nazaré, Silva; Priscilla Mendonça, Matos; Eder Henrique da, Silva; Vladimir Constantino Gomes, Heleno; Norberto Peporine, Lopes; João Luis Callegari, Lopes; Daiane Cristina, Sass.

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

  2. RF characteristic measurement of the model cavities towards development of C-band disk-loaded type accelerating structure

    International Nuclear Information System (INIS)

    We studied on a C-band accelerating structure for the higher pulse rate than 120 pps in SACLA (SPring-8 Angstrom Compact free electron LAser) facility. Due to increase in heat dissipation, the existing choke-mode type accelerating structure has distortions of the cavity diameter 1 ?m or more, which shifts the resonant frequency with about -130 kHz. We designed a new C-band disk-loaded type accelerating structure without the complicated choke structures to generate an accelerating gradient of more than 40 MV/m at the pulse rate. A cross sectional shape of iris designed an ellipsoidal curvature to reduce the maximum surface electric field. Thereby, the maximum surface electric field is 20% lower than the existing structure. We made three types of 9-cell model cavity to estimate the RF characteristics and to establish the fabrication process. As a result, the average shunt impedance of the model cavities was 64 M?/m. An accelerating gradient of 42 MV/m will be expected, when an input RF power of 80 MW is fed into the structure. (author)

  3. 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.

  4. Response Analyses of Tuned Mass Dampers to Structures Exposed to Vortex Loading of Simiu-Scanlan Type

    DEFF Research Database (Denmark)

    Andersen, Lars; Birch, N. W.; Hansen, A. H.; Skibelund, J.-O.

    2001-01-01

    Vortex-induced loads on slender one-dimensional structures vibrating at lock-in conditions consist of a self-induced part in phase with the velocity of the structure in addition to an additive, almost harmonially varying component representing the same type of load as the vortex-induced force on a fixed cylinder. Simiu and Scanlan (1996 Wind Effects on Structures. New York: John Wiley & Sons Inc.) have proposed a widely used model for the self-induced part of the load based on a van der Pol osci...

  5. In situ bulk structural investigation of Mo5O14-type mixed metal oxide catalysts for partial oxidation reactions

    OpenAIRE

    Rödel, Eva

    2007-01-01

    The calcination and thermal activation of a MoVW oxide precursor into Mo5O14-type structure were investigated by in situ X-ray diffraction (XRD), in situ X-ray absorption spectroscopy (XAS), Thermogravimetry and Difference scanning calorimetry (TG/ DSC) measurements. The observed (redox) stability and (redox) properties of (Mo0.68V0.23W0.09)5O14 are compared to (Mo0.91V0.09)5O14 material and correlated to a structural characterization of both structures by XRD and EXAFS. The crystallized MoVW...

  6. Thermoelectric material including a multiple transition metal-doped type I clathrate crystal structure

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Jihui (Lakeshore, CA); Shi, Xun (Troy, MI); Bai, Shengqiang (Shanghai, CN); Zhang, Wenqing (Shanghai, CN); Chen, Lidong (Shanghai, CN); Yang, Jiong (Shanghai, CN)

    2012-01-17

    A thermoelectric material includes a multiple transition metal-doped type I clathrate crystal structure having the formula A.sub.8TM.sub.y.sub.1.sup.1TM.sub.y.sub.2.sup.2 . . . TM.sub.y.sub.n.sup.nM.sub.zX.sub.46-y.sub.1.sub.-y.sub.2.sub.- . . . -y.sub.n.sub.-z. In the formula, A is selected from the group consisting of barium, strontium, and europium; X is selected from the group consisting of silicon, germanium, and tin; M is selected from the group consisting of aluminum, gallium, and indium; TM.sup.1, TM.sup.2, and TM.sup.n are independently selected from the group consisting of 3d, 4d, and 5d transition metals; and y.sub.1, y.sub.2, y.sub.n and Z are actual compositions of TM.sup.1, TM.sup.2, TM.sup.n, and M, respectively. The actual compositions are based upon nominal compositions derived from the following equation: z=8q.sub.A-|.DELTA.q.sub.1|y.sub.1-|.DELTA.q.sub.2|y.sub.2- . . . -|.DELTA.q.sub.n|y.sub.n, wherein q.sub.A is a charge state of A, and wherein .DELTA.q.sub.1, .DELTA.q.sub.2, .DELTA.q.sub.n are, respectively, the nominal charge state of the first, second, and n-th TM.

  7. 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.

  8. Crystal structure of YSiO2N and a reappraisal of the ''vaterite'' type, YBO3

    International Nuclear Information System (INIS)

    Intensity calculations on powder patterns of YSiO2N indicate it to have an ?-CaSiO3, pseudowollastonite structure. The great similarity to YBO3 led to an investigation of the ''pseudo-vaterite'' types which appear also to be, in fact, pseudowollastonites

  9. Structural models of the human copper P-type ATPases ATP7A and ATP7B

    DEFF Research Database (Denmark)

    Gourdon, Pontus; Sitsel, Oleg

    2012-01-01

    The human copper exporters ATP7A and ATP7B contain domains common to all P-type ATPases as well as class-specific features such as six sequential heavy-metal binding domains (HMBD1-HMBD6) and a type-specific constellation of transmembrane helices. Despite the medical significance of ATP7A and ATP7B related to Menkes and Wilson diseases, respectively, structural information has only been available for isolated, soluble domains. Here we present homology models based on the existing structures of soluble domains and the recently determined structure of the homologous LpCopA from the bacterium Legionella pneumophila. The models and sequence analyses show that the domains and residues involved in the catalytic phosphorylation events and copper transfer are highly conserved. In addition, there are only minor differences in the core structures of the two human proteins and the bacterial template, allowing protein-specific properties to be addressed. Furthermore, the mapping of known disease-causing missense mutations indicates that among the heavy-metal binding domains, HMBD5 and HMBD6 are the most crucial for function, thus mimicking the single or dual HMBDs found in most copper-specific P-type ATPases. We propose a structural arrangement of the HMBDs and how they may interact with the core of the proteins to achieve autoinhibition.

  10. Structures and physical properties of epsilon-FeSi-type and CsCl-type RuSi studied by first-principles pseudopotential calculations

    Science.gov (United States)

    Vocadlo; Price; Wood

    2000-06-01

    An investigation of the relative stability of the two known polymorphs of RuSi, having the epsilon-FeSi and CsCl structures, has been made by first-principles pseudopotential calculations. The resulting cell volumes and fractional coordinates at P = 0 are in good agreement with experiment. Application of high pressure to the epsilon-FeSi phase of RuSi is predicted to produce a structure having almost perfect sevenfold coordination. However, it appears that RuSi having the CsCl-type structure will be the thermodynamically most stable phase for pressures greater than 3.6 GPa. Fitting of the calculated internal energy versus volume to a fourth-order logarithmic equation of state led to values (at T = 0 K) for the bulk modulus, K0, of 202 and 244 GPa for the epsilon-FeSi and CsCl phases, respectively, in excellent agreement with experiment. Band-structure calculations for both phases are also presented. PMID:10877344

  11. The Use of Metal Fluoride Compounds as Phosphate Analogs for Understanding the Structural Mechanism in P-type ATPases.

    Science.gov (United States)

    Danko, Stefania J; Suzuki, Hiroshi

    2016-01-01

    The membrane-bound protein family, P-type ATPases, couples ATP hydrolysis with substrate transport across the membrane and forms an obligatory auto-phosphorylated intermediate in the transport cycle. The metal fluoride compounds, BeF x , AlF x , and MgF x , as phosphate analogs stabilize different enzyme structural states in the phosphoryl transfer/hydrolysis reactions, thereby fixing otherwise short-lived intermediate and transient structural states and enabling their biochemical and atomic-level crystallographic studies. The compounds thus make an essential contribution for understanding of the ATP-driven transport mechanism. Here, with a representative member of P-type ATPase, sarco(endo)plasmic reticulum Ca(2+)-ATPase (SERCA), we describe the method for their binding and for structural and functional characterization of the bound states, and their assignments to states occurring in the transport cycle. PMID:26695034

  12. Multi-virulence-locus sequence typing of Staphylococcus lugdunensis generates results consistent with a clonal population structure and is reliable for epidemiological typing.

    Science.gov (United States)

    Didi, Jennifer; Lemée, Ludovic; Gibert, Laure; Pons, Jean-Louis; Pestel-Caron, Martine

    2014-10-01

    Staphylococcus lugdunensis is an emergent virulent coagulase-negative staphylococcus responsible for severe infections similar to those caused by Staphylococcus aureus. To understand its potentially pathogenic capacity and have further detailed knowledge of the molecular traits of this organism, 93 isolates from various geographic origins were analyzed by multi-virulence-locus sequence typing (MVLST), targeting seven known or putative virulence-associated loci (atlLR2, atlLR3, hlb, isdJ, SLUG_09050, SLUG_16930, and vwbl). The polymorphisms of the putative virulence-associated loci were moderate and comparable to those of the housekeeping genes analyzed by multilocus sequence typing (MLST). However, the MVLST scheme generated 43 virulence types (VTs) compared to 20 sequence types (STs) based on MLST, indicating that MVLST was significantly more discriminating (Simpson's index [D], 0.943). No hypervirulent lineage or cluster specific to carriage strains was defined. The results of multilocus sequence analysis of known and putative virulence-associated loci are consistent with a clonal population structure for S. lugdunensis, suggesting a coevolution of these genes with housekeeping genes. Indeed, the nonsynonymous to synonymous evolutionary substitutions (dN/dS) ratio, the Tajima's D test, and Single-likelihood ancestor counting (SLAC) analysis suggest that all virulence-associated loci were under negative selection, even atlLR2 (AtlL protein) and SLUG_16930 (FbpA homologue), for which the dN/dS ratios were higher. In addition, this analysis of virulence-associated loci allowed us to propose a trilocus sequence typing scheme based on the intragenic regions of atlLR3, isdJ, and SLUG_16930, which is more discriminant than MLST for studying short-term epidemiology and further characterizing the lineages of the rare but highly pathogenic S. lugdunensis. PMID:25078912

  13. Different Types of Cell-to-Cell Connections Mediated by Nanotubular Structures

    OpenAIRE

    Verani?, Peter; Lokar, Maruša; Schütz, Gerhard J.; Weghuber, Julian; Wieser, Stefan; Hägerstrand, Henry; Kralj-Igli?, Veronika; Igli?, Aleš

    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...

  14. Structure and properties of ?-NaFeO{sub 2}-type ternary sodium iridates

    Energy Technology Data Exchange (ETDEWEB)

    Baroudi, Kristen, E-mail: kbaroudi@princeton.edu [Department of Chemistry, Princeton University, Princeton, NJ 08544 (United States); Yim, Cindi [Department of Chemistry, Princeton University, Princeton, NJ 08544 (United States); Wu, Hui [NIST Center for Neutron Research, Gaithersburg, MD 20899-6102 (United States); Department of Materials Science and Engineering, University of Maryland, College Park, MD 20742-2115 (United States); Huang, Qingzhen [NIST Center for Neutron Research, Gaithersburg, MD 20899-6102 (United States); Roudebush, John H. [Department of Chemistry, Princeton University, Princeton, NJ 08544 (United States); Vavilova, Eugenia [Leibniz Institute for Solid State and Materials Research IFW, Dresden (Germany); Zavoisky Physical Technical Institute, Russian Academy of Sciences, Kazan (Russian Federation); Grafe, Hans-Joachim; Kataev, Vladislav [Leibniz Institute for Solid State and Materials Research IFW, Dresden (Germany); Buechner, Bernd [Leibniz Institute for Solid State and Materials Research IFW, Dresden (Germany); Institut für Festkörperphysik, Technische Universität Dresden, Dresden (Germany); Ji, Huiwen [Department of Chemistry, Princeton University, Princeton, NJ 08544 (United States); Kuo, Changyang; Hu, Zhiwei; Pi, Tun-Wen [Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Straße 40, 01187 Dresden (Germany); Pao, Chiwen; Lee, Jyhfu [National Synchrotron Radiation Research Center, Hsinchu 30076, Taiwan, ROC (China); Mikhailova, Daria; Hao Tjeng, Liu [Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Straße 40, 01187 Dresden (Germany); Cava, R.J. [Department of Chemistry, Princeton University, Princeton, NJ 08544 (United States)

    2014-02-15

    The synthesis, structure, and elementary magnetic and electronic properties are reported for layered compounds of the type Na{sub 3?x}MIr{sub 2}O{sub 6} and Na{sub 3?x}M{sub 2}IrO{sub 6}, where M is a transition metal from the 3d series (M=Zn, Cu, Ni, Co, Fe and Mn). The rhombohedral structures, in space group R?3m, were determined by refinement of neutron and synchrotron powder diffraction data. No clear evidence for long range 2:1 or 1:2 honeycomb-like M/Ir ordering was found in the neutron powder diffraction patterns except in the case of M=Zn, and thus in general the compounds are best designated as sodium deficient ?-NaFeO{sub 2}-type phases with formulas Na{sub 1?x}M{sub 1/3}Ir{sub 2/3}O{sub 2} or Na{sub 1?x}M{sub 2/3}Ir{sub 1/3}O{sub 2}. Synchrotron powder diffraction patterns indicate that several of the compounds likely have honeycomb in-plane metal–iridium ordering with disordered stacking of the layers. All the compounds are sodium deficient under our synthetic conditions and are black and insulating. Weiss constants derived from magnetic susceptibility measurements indicate that Na{sub 0.62}Mn{sub 0.61}Ir{sub 0.39}O{sub 2}, Na{sub 0.80}Fe{sub 2/3}Ir{sub 1/3}O{sub 2}, Na{sub 0.92}Ni{sub 1/3}Ir{sub 2/3}O{sub 2}, Na{sub 0.86}Cu{sub 1/3}Ir{sub 2/3}O{sub 2}, and Na{sub 0.89}Zn{sub 1/3}Ir{sub 2/3}O{sub 2} display dominant antiferromagnetic interactions. For Na{sub 0.90}Co{sub 1/3}Ir{sub 2/3}O{sub 2} the dominant magnetic interactions at low temperature are ferromagnetic while at high temperatures they are antiferromagnetic; there is also a change in the effective moment. Low temperature specific heat measurements (to 2 K) on Na{sub 0.92}Ni{sub 1/3}Ir{sub 2/3}O{sub 2} indicate the presence of a broad magnetic ordering transition. X-ray absorption spectroscopy shows that iridium is at or close to the 4+ oxidation state in all compounds. {sup 23}Na nuclear magnetic resonance measurements comparing Na{sub 2}IrO{sub 3} to Na{sub 0.92}Ni{sub 1/3}Ir{sub 2/3}O{sub 2} and Na{sub 0.89}Zn{sub 1/3}Ir{sub 2/3}O{sub 2} provide strong indications that the electron spins are short-range ordered in the latter two materials. Na{sub 0.62}Mn{sub 0.61}Ir{sub 0.39}O{sub 2}, Na{sub 0.80}Fe{sub 2/3}Ir{sub 1/3}O{sub 2}, Na{sub 0.90}Co{sub 1/3}Ir{sub 2/3}O{sub 2}, Na{sub 0.92}Ni{sub 1/3}Ir{sub 2/3}O{sub 2}, Na{sub 0.86}Cu{sub 1/3}Ir{sub 2/3}O{sub 2} and Na{sub 0.89}Zn{sub 1/3}Ir{sub 2/3}O{sub 2} are spin glasses. (CSD-numbers: Na{sub 0.62}Mn{sub 0.61}Ir{sub 0.39}O{sub 2}: 426657, Na{sub 0.80}Fe{sub 2/3}Ir{sub 1/3}O{sub 2}: 426659, Na{sub 0.90}Co{sub 1/3}Ir{sub 2/3}O{sub 2}: 426658, Na{sub 0.92}Ni{sub 1/3}Ir{sub 2/3}O{sub 2}: 426656, Na{sub 0.86}Cu{sub 1/3}Ir{sub 2/3}O{sub 2}: 426655, and Na{sub 2.8}ZnIr{sub 2}O{sub 6}: 426660.) - Graphical abstract: Diffraction patterns of Na{sub 0.92}Ni{sub 1/3}Ir{sub 2/3}O{sub 2}, Na{sub 0.86}Cu{sub 1/3}Ir{sub 2/3}O{sub 2} and Na{sub 0.89}Zn{sub 1/3}Ir{sub 2/3}O{sub 2}: neutron diffraction patterns in the main panel and synchrotron diffraction in the insets. The patterns show a small amount of ordering in the transition metal iridium layer. Display Omitted - Highlights: • We report six ternary sodium iridates with the ?-NaFeO{sub 2} structure. • Compounds Na{sub 1?x}M{sub 1/3}Ir{sub 2/3}O{sub 2}, M=Co, Ni, Cu, Zn and Na{sub 1?x}M{sub 2/3}Ir{sub 1/3}O{sub 2}, M=Mn, Fe. • Rietveld refinement of powder neutron diffraction data. • All compounds are spin glasses. • NMR comparison to Na{sub 2}IrO{sub 3}.

  15. A series of aluminum tungsten oxides crystallizing in a new ReO3-related structure type

    International Nuclear Information System (INIS)

    A series of new aluminum tungsten oxides with the general formula Al4W2nO6n+2 (n=4-7) was found and structurally characterized by electron diffraction, high-resolution transmission electron microscopy (HRTEM) and high angle annular dark field scanning transmission electron microscopy (HAADF-STEM). The structural model for Al4W10O32 (I4/mmm (space group no. 139); a?0.375, c?3.95 nm) consists of slabs of [5x?x?] corner-sharing WO6 octahedra that are connected via edge-sharing to AlO6 octahedra. Simulated HRTEM images agree well with the experimental ones and thus support the proposed structural model. The connection between adjacent slabs of WO3 via AlO6 octahedra represents a novel variant of crystallographic shear operation for ReO3-type structures. The crystallites display a wide range of stacking sequences that are frequently intergrown with each other. - Graphical abstract: A structural model for Al4W10O32 was derived from electron diffraction, HRTEM and HAADF-STEM observations. The ReO3-type structure of WO3 is sheared into five octahedra wide slabs that are connected via planes of AlO6 octahedra. Polytypes with different slab width exist and are frequently intergrown with each other

  16. Enthalpy stabilization of complex oxides Ln4Cu3MoO12 with the YMnO3-type structure

    International Nuclear Information System (INIS)

    Enthalpies of formation of Ln4Cu3MoO12 (Ln = La, Pr, Nd, Sm), featuring the YMnO3 type structure, from simple oxides, bearing in mind changes in cation coordination, were calculated by approximated method of calculation. It is shown that compounds of the structural type are more stable thermochemically than compounds with perovskite-type structure of the same stoichiometry

  17. Sibling Structure and Parental Sex-Typing of Children's Household Tasks.

    Science.gov (United States)

    Brody, Charles J.; Steelman, Lala Carr

    1985-01-01

    Tests whether an increase in number of sons in the family decreases the sex-typing of traditionally female tasks and whether an increase in the number of daughters increases sex-typing of traditionally female chores. Examines the reverse pattern for male chores. Results support the hypotheses for the female-specific tasks. (BH)

  18. Effects of Family Structure Type and Stability on Children's Academic Performance Trajectories

    Science.gov (United States)

    Sun, Yongmin; Li, Yuanzhang

    2011-01-01

    Using five waves of panel data from 8,008 children in the ECLS-K, the current study compared children's academic performance growth curves from kindergarten through fifth grade among three types of nondisrupted and three types of disrupted families. The analyses found that children in nondisrupted two-biological-parent and nondisrupted stepparent…

  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. 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.

  1. 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.

  2. Effect of preparation conditions on fractal structure and phase transformations in the synthesis of nanoscale M-type barium hexaferrite

    International Nuclear Information System (INIS)

    The conditions of the synthesis of carbonate-hydroxide precursors (pH of FeOOH precipitation and heat treatment regimes) were studied in terms of their effect on the fractal structure and physical-chemical properties of precursors. Phase transformations which occur during the synthesis of nanosize M-type barium hexaferrite (BHF) were studied as well. The first structural level of precursors' aggregation for mass fractals, the correlation between fractal dimension and precursors' activity during the synthesis of BHF were determined. Synthesis parameters for the precursors with the optimal fractal structure were determined. These data permit an enhancement of the filtration coefficient of the precipitates by a factor of 4-5, obtaining substantial decrease in the temperature required for synthesis of a single-phase BHF, and monodispersed plate-like nanoparticles (60 nm diameter) with the shape anisotropy and good magnetic characteristics (saturation magnetization (Ms)=68,7 emu/g and coercitivity (Hc)=5440 Oe). - Highlights: ? The nanosize M-type BHF obtained by precipitation of hydroxicarbonates technique. ? Optimal fractal structure of a precursor for nanosize M-type BHF has been determined. ? The precursor precipitated at pH 4.3 allows getting monodisperse particles of BHF.

  3. Effect of preparation conditions on fractal structure and phase transformations in the synthesis of nanoscale M-type barium hexaferrite

    Energy Technology Data Exchange (ETDEWEB)

    Pashkova, E.V. [V.I. Vernadskii Institute of General and Inorganic Chemistry, 32/34 Prospect Palladina, Kyiv-142, 03680 (Ukraine); Solovyova, E.D., E-mail: solovyovak@mail.ru [V.I. Vernadskii Institute of General and Inorganic Chemistry, 32/34 Prospect Palladina, Kyiv-142, 03680 (Ukraine); Kotenko, I.E., E-mail: Hab2420@yahoo.com [National Technical University of Ukraine ' KPI' , Pr. Pobedy, 37, Kyiv-57 (Ukraine); Kolodiazhnyi, T.V., E-mail: kolodiazhnyi.taras@nims.go.jp [National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki 305-0044 (Japan); Belous, A.G., E-mail: belous@ionc.kar.net [V.I. Vernadskii Institute of General and Inorganic Chemistry, 32/34 Prospect Palladina, Kyiv-142, 03680 (Ukraine)

    2011-10-15

    The conditions of the synthesis of carbonate-hydroxide precursors (pH of FeOOH precipitation and heat treatment regimes) were studied in terms of their effect on the fractal structure and physical-chemical properties of precursors. Phase transformations which occur during the synthesis of nanosize M-type barium hexaferrite (BHF) were studied as well. The first structural level of precursors' aggregation for mass fractals, the correlation between fractal dimension and precursors' activity during the synthesis of BHF were determined. Synthesis parameters for the precursors with the optimal fractal structure were determined. These data permit an enhancement of the filtration coefficient of the precipitates by a factor of 4-5, obtaining substantial decrease in the temperature required for synthesis of a single-phase BHF, and monodispersed plate-like nanoparticles (60 nm diameter) with the shape anisotropy and good magnetic characteristics (saturation magnetization (M{sub s})=68,7 emu/g and coercitivity (H{sub c})=5440 Oe). - Highlights: > The nanosize M-type BHF obtained by precipitation of hydroxicarbonates technique. > Optimal fractal structure of a precursor for nanosize M-type BHF has been determined. > The precursor precipitated at pH 4.3 allows getting monodisperse particles of BHF.

  4. 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; Poulsen, Lars K.; Hummelshoj, L; Bindslev-Jensen, Carsten; Burks, A W; Sampson, H A

    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 d...

  5. Expression and characterization of P-type ATPases for structural studies

    OpenAIRE

    Chintalapati, Sivaram Chandra

    2007-01-01

    Two types of proteins transport ions across the membrane – ion channels and ion pumps. Ion pumps transport ions against their electrochemical gradient by co-transporting another ion or a substrate molecule through a concentration gradient or by coupling this process to an energy source like ATP. Those that couple ATP hydrolysis to ion transport are called ion motive ATPases and can be classified as ‘V’, ‘F’ and ‘P’ types. In this thesis, two sub-classes of P-type ATPases, PIIIA and PIB were s...

  6. Data with Hierarchical Structure: Impact of Intraclass Correlation and Sample Size on Type-I Error

    OpenAIRE

    Musca, Serban C.; Kamiejski, Rodolphe; Nugier, Armelle; Méot, Alain; Er-Rafiy, Abdelatif; Brauer, Markus

    2011-01-01

    Least squares analyses (e.g., ANOVAs, linear regressions) of hierarchical data leads to Type-I error rates that depart severely from the nominal Type-I error rate assumed. Thus, when least squares methods are used to analyze hierarchical data coming from designs in which some groups are assigned to the treatment condition, and others to the control condition (i.e., the widely used “groups nested under treatment” experimental design), the Type-I error rate is seriously inflated, leading too of...

  7. A quick seismic assessment method for jacket type offshore structures by combining push-over and nonlinear time history analyses

    Energy Technology Data Exchange (ETDEWEB)

    Karimiyan, S.; Hosseini, M. [International Inst. of Earthquake Engineering and Seismology, Tehran (Iran, Islamic Republic of); Karimiyan, M. [Islamic Azad Univ., Tehran (Iran, Islamic Republic of). Earthquake Eng. Dept., School of Engineering

    2010-07-01

    Several offshore structures are located in seismic regions. In order to upgrade their seismic behaviour, their seismic vulnerability must be evaluated. It is thought that the most reliable type of analysis for seismic evaluation is nonlinear time history analysis (NLTHA), however, it is known to be a very time consuming method. This paper presented a quick procedure by combining the push over analysis (POA) and the NLTHA. The paper discussed both methods in detail. In order to identify the more critical members of the structure, based on the range of their plastic deformations, some POA were first performed. The NLTHA was then performed, focusing on the critical members, to obtain their vulnerability with higher reliability. An offshore structure of jacket type, installed in the Lavan oil field in the Persian Gulf in 1970, was also considered in order to demonstrate the efficiency of the proposed method. It was concluded from the numerical results that combining POA and NLTHA was a quick and reliable seismic evaluation method. The results demonstrated that although the vulnerability of the jacket structure was not very high, the level of damage was not the same for different members, and was dependent on their location in the structure and also its geometric orientation and load bearing situation. 6 refs., 1 tab., 8 figs.

  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. Pt-B System Revisited: Pt2B, a New Structure Type of Binary Borides. Ternary WAl12-Type Derivative Borides.

    Science.gov (United States)

    Sologub, Oksana; Salamakha, Leonid; Rogl, Peter; Stöger, Berthold; Bauer, Ernst; Bernardi, Johannes; Giester, Gerald; Waas, Monika; Svagera, Robert

    2015-11-16

    On the basis of a detailed study applying X-ray single-crystal and powder diffraction, differential scanning calorimetry, and scanning electron microscopy analysis, it was possible to resolve existing uncertainties in the Pt-rich section (?65 atom % Pt) of the binary Pt-B phase diagram above 600 °C. The formation of a unique structure has been observed for Pt2B [X-ray single-crystal data: space group C2/m, a = 1.62717(11) nm, b = 0.32788(2) nm, c = 0.44200(3) nm, ? = 104.401(4)°, RF2 = 0.030]. Within the homogeneity range of "Pt3B", X-ray powder diffraction phase analysis prompted two structural modifications as a function of temperature. The crystal structure of "hT-Pt3B" complies with the hitherto reported structure of anti-MoS2 [space group P63/mmc, a = 0.279377(2) nm, c = 1.04895(1) nm, RF = 0.075, RI = 0.090]. The structure of the new "[Formula: see text]T-Pt3B" is still unknown. The formation of previously reported Pt?4B has not been confirmed from binary samples. Exploration of the Pt-rich section of the Pt-Cu-B system at 600 °C revealed a new ternary compound, Pt12CuB6-y [X-ray single-crystal data: space group Im3?, a = 0.75790(2) nm, y = 3, RF2 = 0.0129], which exhibits the filled WAl12-type structure accommodating boron in the interstitial trigonal-prismatic site 12e. The isotypic platinum-aluminum-boride was synthesized and studied. The solubility of copper in binary platinum borides has been found to attain ?7 atom % Cu for Pt2B but to be insignificant for "[Formula: see text]T-Pt3B". The architecture of the new Pt2B structure combines puckered layers of boron-filled and empty [Pt6] octahedra (anti-CaCl2-type fragment) alternating along the x axis with a double layer of boron-semifilled [Pt6] trigonal prisms interbedded with a layer of empty tetrahedra and tetragonal pyramids (B-deficient ?-T[Formula: see text]I fragment). Assuming boron vacancies ordering (space group R3), the Pt12CuB6-y structure exhibits serpentine-like columns of edge-connected boron-filled [Pt6] trigonal prisms running infinitely along the z axis and embedding the icosahedrally coordinated Cu atom. Pt2B, (Pt1-yCuy)2B (y = 0.045), and Pt12CuB6-y (y = 3) behave metallically, as revealed by temperature-dependent electrical resistivity measurements. PMID:26524081

  10. Al-doping effect on the structural and physical properties of delafossite-type oxide CuCrO2

    International Nuclear Information System (INIS)

    The structure, Raman spectroscopy, magnetization, and dielectric properties of delafossite-type oxide CuCr1-xAlxO2 have been characterized. It was found that Al substitution generates an anisotropic effect on the structure, besides magnetic dilution. The temperature dependence of all samples exhibits paramagnetic behavior at high temperature. Above x=0.2 the ferromagnetic transition at 120 K disappears. It is argued that Al substitution destabilizes the antiferromagnetic order of Cr3+ ions and modulates the spin configuration, leading to a weak ferromagnetism. The coupling between the magnetic order and ferroelectric order is also characterized.

  11. The Delsarte-Darboux type binary transformations, their differential-geometric and operator structure with applications. Part 1

    Directory of Open Access Journals (Sweden)

    Yarema A. Prykarpatsky

    2006-01-01

    Full Text Available The structure properties of multidimensional Delsarte–Darboux transmutation operators in parametric functional spaces are studied by means of differential-geometric and topological tools. It is shown that kernels of the corresponding integral operator expressions depend on the topological structure of related homological cycles in the coordinate space. As a natural realization of the construction presented we build pairs of Lax type commutative differential operator expressions related via a Delsarte–Darboux transformation and having a lot of applications in soliton theory.

  12. 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)

  13. Crystal structures of wild-type and mutated cyclophilin B that causes hyperelastosis cutis in the American quarter horse

    Directory of Open Access Journals (Sweden)

    Boudko Sergei P

    2012-11-01

    Full Text Available Abstract Background Hyperelastosis cutis is an inherited autosomal recessive connective tissue disorder. Affected horses are characterized by hyperextensible skin, scarring, and severe lesions along the back. The disorder is caused by a mutation in cyclophilin B. Results The crystal structures of both wild-type and mutated (Gly6->Arg horse cyclophilin B are presented. The mutation neither affects the overall fold of the enzyme nor impairs the catalytic site structure. Instead, it locally rearranges the flexible N-terminal end of the polypeptide chain and also makes it more rigid. Conclusions Interactions of the mutated cyclophilin B with a set of endoplasmic reticulum-resident proteins must be affected.

  14. Electronic band structure of zinc blende CdSe and rock salt PbSe semiconductors with silicene-type honeycomb geometry

    Science.gov (United States)

    Delerue, Christophe; Vanmaekelbergh, D.

    2015-09-01

    We report on the electronic band structure of 2D CdSe and PbSe semiconductors that have a silicene-type honeycomb geometry. Atomistic tight-binding calculations are performed on several model systems that bear a strong resemblance to the silicene-type honeycomb structures that were recently obtained by nanocrystal self-assembly. The calculated band structures are compared both to those of 2D quantum wells and graphene-type honeycomb structures. It is found that in silicene type CdSe honeycomb structures, the lowest electron conduction bands (derived from S-type nanocrystal wave functions) form a Dirac-type dispersion, very similar as in graphene. The P-type bands are usually more complex. However, when the hybridization between S- and P-type bands increases, a second Dirac cone and a genuine non-trivial flat band is observed, similar as in the case of graphene-type honeycomb structures of CdSe. There is a strong non-trivial gap between the first and second valence band, hosting the quantum spin Hall effect. Silicene-type PbSe structures show Dirac features in their bands, which however can be clouded due to the multi-valley character of PbSe.

  15. Structural studies on a non toxic homologue of type II RIPs from bitter gourd: Molecular basis of non toxicity, conformational selection and glycan structure

    Indian Academy of Sciences (India)

    Thyageshwar Chandran; Alok Sharma; M Vijayan

    2015-12-01

    The structures of nine independent crystals of bitter gourd seed lectin (BGSL), a non-toxic homologue of type II RIPS, and its sugar complexes have been determined. The four-chain, two-fold symmetric, protein is made up of two identical two-chain modules, each consisting of a catalytic chain and a lectin chain, connected by a disulphide bridge. The lectin chain is made up of two domains. Each domain carries a carbohydrate binding site in type II RIPS of known structure. BGSL has a sugar binding site only on one domain, thus impairing its interaction at the cell surface. The adenine binding site in the catalytic chain is defective. Thus, defects in sugar binding as well as adenine binding appear to contribute to the non-toxicity of the lectin. The plasticity of the molecule is mainly caused by the presence of two possible well defined conformations of a surface loop in the lectin chain. One of them is chosen in the sugar complexes, in a case of conformational selection, as the chosen conformation facilitates an additional interaction with the sugar, involving an arginyl residue in the loop. The -glycosylation of the lectin involves a plant-specific glycan while that in toxic type H RIPS of known structure involves a glycan which is animal as well as plant specific.

  16. Sandwich-type polymer nanofiber structure of poly(furfuryl alcohol): an effective template for ordered porous films.

    Science.gov (United States)

    Gao, Feng; Lu, Qingyi; Pang, Huan; Komarneni, Sridhar

    2009-09-17

    A brand new sandwich-type poly(furfuryl alcohol) (PFA) nanostructure as well as ordered PFA nanofiber arrays has been successfully obtained through a novel two-step polymerization method by using a porous alumina membrane as the template. This novel structure is made up of ordered PFA nanopillars supported by two PFA films on the top and bottom. The thickness of the PFA films on both sides could be adjusted from several micrometers to tens of micrometers, and the flexibility of the membrane could be controlled in a certain range. This sandwich-type polymer nanostructure can be used as an effective template for constructing other ordered porous films resembling the structure of the parent alumina membrane, and in this study, ordered porous titania membrane has been successfully obtained. Theoretically, many other novel porous (or meso- and macro-mixed porous) materials could be synthesized through this novel template. PMID:19702291

  17. Magnetic order and crystal structure study of YNi4Si-type NdNi4Si

    Science.gov (United States)

    Yao, Jinlei; Isnard, O.; Morozkin, A. V.; Ivanova, T. I.; Koshkid`ko, Yu. S.; Bogdanov, A. E.; Nikitin, S. A.; Suski, W.

    2015-02-01

    Magnetic measurements and neutron powder diffraction investigation of the magnetic structure of the orthorhombic YNi4Si-type (space group Cmmm) NdNi4Si compound are presented. The magnetocaloric effect of NdNi4Si is calculated in terms of the isothermal magnetic entropy change and it reaches the maximum value of -3.3 J/kg K for a field change of 50 kOe near TC=12 K. Below ~12 K, NdNi4Si exhibits a commensurate b-axis collinear ferromagnetic ordering with the Cmm?m magnetic space group in a zero magnetic field. At 1.5 K, the neodymium atoms have the magnetic moment of 2.37(5) ?B. The orthorhombic crystal structure and its thermal evolution are discussed in comparison with the CaCu5-type compound.

  18. Internal Materials and structural Investigations of C-type Asteroid using carry-on Impactor by Hayabusa-2

    Science.gov (United States)

    Okamoto, Chisato; Takagi, Yasuhiko; Yano, Hajime; Saiki, Takanao; Tsuda, Yuichi; Yoshikawa, Makoto

    Recent explorations carried out by spacecraft provided important information regarding the physical properties of asteroids, particularly their bulk density and surface morphology. For example, Hayabusa spacecraft launched in 2003 investigated 25143 Itokawa, an S-type asteroid, after it arrived at 25143 Itokawa in September, 2005. Hayabusa has made a large amount of scientific discoveries and technological achievements during its stay, and left Itokawa in December, 2005 in order to deliver us the surface material. Observations by the Hayabusa spacecraft revealed that 25143 Itokawa has a rubble-pile structure owing to the re-accumulation of disrupted impact fragments. Itokawa has a high porosity (˜40%), probably because of the macro-porosity among the disrupted fragments. Based on such previous observations, it is proposed that the internal structures of asteroids have diversity in bulk densities and porosities. However, we have no direct observational data for the internal structure and materials. It is possible that the surface materials of small bodies seriously damaged by cosmic ray exposure. Thus, we should investigate the chemical and physical properties of the internal material. Also, we need to investigate the internal structure in order to understand the formation history. Now we are planning the study of the next asteroid exploration mission in 2014. From the point of the scientific objective, 1999 JU3, a C-type asteroid, was chosen as the target; C-type asteroids are considered to have more primitive material such as organic matters in comparison to Itokawa, an S-type asteroid. The spacecraft called as Hayabusa-2 basically follows the design of Hayabusa spacecraft. But, we will develop some new equipment to investigate the C-type asteroid, especially a carry-on impactor for the internal materials and structural investigations. The impactor will be shoot on the asteroid at ˜2km/s in order to expose the internal materials via crater formation and induce seismicity by the impact. The size and weight of impactor is restricted because the possible payload mass of Hayabusa-2 is not so large; its system should be very simple. If we use the rocket motor, the acceleration distance becomes large and the guidance system is necessary for the accurate impact. Additionally, the impact will cause a serious contamination by mechanical mixture of the impactor into the asteroid sample during crater formation process. Hence we adopt powerful explosive to accelerate the metal impact head and we shorten the accelerate time (less than 1 ms). In the presentation we will give an overview of a C-type asteroid investigation using the small carry-on impactor of Hayabusa-2.

  19. Features design solutions that can be applied to the frame type structures for construction in seismic areas

    Directory of Open Access Journals (Sweden)

    ?.?. ???????

    2008-03-01

    Full Text Available  The article considers some of the structural decisions that can be used when designing seismically resistant skeleton type buildings in the seismical regions of Ukraine. The major drawbacks and benefits are considered on the example of a concrete building – skeleton of logistics complex typical block that is to be constructed in the region having design seismicity equal to 8 points by MSK-64 scale.

  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. Possible fluorite-type structure M3+Ln3+F18

    International Nuclear Information System (INIS)

    A model of crystal structure is suggested for the Na3Yb5F18 phase discovered in the NaF-YbF3 system. The model is based on the Na8Yb6F69 clusters obtained by transformation of the fluorite structure fragment M14F64. The formulae of the compounds is [Na15Yb][Yb12][Yb12]F90 with respect to the structural role of the cations. Possible occurrence of the M3Ln5F18 phases (M=Na, K, Rb; Ln=La-Lu, Y) is discussed

  2. 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

  3. Detection and localization of contact-type damages via nonlinear impedance modulation of piezoelectric materials bonded on a beam structure

    Science.gov (United States)

    Masuda, Arata; Aoki, Junsuke; Iba, Daisuke; Sone, Akira

    2010-03-01

    In this paper, a nondestructive, in-service structural integrity monitoring methodology that can detect and characterize local structural damages of contact-type, i.e. damages and failures which come along with generation, growth and/or changes of contacting surfaces, such as cracks, debonding, preload-loss in bolted joints, etc., is presented. The presented monitoring system consists of piezoelectric elements bonded on the structural surface, a high-frequency harmonic voltage source, and a current detector. When the structure is subjected to a vibrational load such as operational load at low-frequencies, the scattering conditions for the high-frequency elastic waves in the vicinity of the contact-type damages will change in synchronization with the structural vibration because of the fluctuation of the contact conditions. This nonlinear effects of vibro-acoustic interaction between the low-frequency vibration and the high-frequency wave field causes the change in the driving-point impedance of the structure at the high frequency range, which leads to the significant modulation of the coupled electro-mechanical impedance (or admittance) of the piezoelectric elements. Therefore, if the piezoelectric elements are driven by a fixed amplitude high-frequency harmonic voltage source, the nonlinear fluctuation of the coupled admittance can be observed as the amplitude and phase modulation of the current flowing through the piezoelectric element. A modeling and analytical study of the nonlinear piezoelectric impedance modulation is presented for a beam structure including a crack, utilizing a linear time-varying system theory. A damage evaluation measure is presented based on the dimensionless modal stiffness fluctuation estimated from the instantaneous admittance reconstructed from the demodulated current responses. Furthermore, fundamental strategies and future directions for damage localization based on the nonlinear piezoelectric impedance modulation are briefly discussed.

  4. AN INVESTIGATION OF THE TYPE M MORPHOLOGICAL STRUCTURE OF IC59: A NEW MODEL FOR BRIGHT RIM CLOUDS?

    International Nuclear Information System (INIS)

    We report the results from a smoothed particle hydrodynamics simulation designed to model recent observational data on the nebula and Bright Rim Cloud IC59. We further examine, in the context of radiative-driven implosion (RDI) models, the possible formation mechanisms of the morphological structure of IC59. The results of the simulation reveal the existence of a new, fourth morphological state for Bright Rim Clouds (BRCs)-which we propose to call a Type M BRC morphology. We discuss the necessary conditions for the appearance of Type M BRCs, based on analytical and numerical simulations. The simulated physical properties from our model are consistent with the available observations of IC59. We further show that the prospect of RDI triggered star formation in all Type M BRCs is not supported by the simulations.

  5. Structure of the VipA/B Type VI Secretion Complex Suggests a Contraction-State-Specific Recycling Mechanism

    Directory of Open Access Journals (Sweden)

    Sebastian Kube

    2014-07-01

    Full Text Available The bacterial type VI secretion system is a multicomponent molecular machine directed against eukaryotic host cells and competing bacteria. An intracellular contractile tubular structure that bears functional homology with bacteriophage tails is pivotal for ejection of pathogenic effectors. Here, we present the 6 Å cryoelectron microscopy structure of the contracted Vibrio cholerae tubule consisting of the proteins VipA and VipB. We localized VipA and VipB in the protomer and identified structural homology between the C-terminal segment of VipB and the tail-sheath protein of T4 phages. We propose that homologous segments in VipB and T4 phages mediate tubule contraction. We show that in type VI secretion, contraction leads to exposure of the ClpV recognition motif, which is embedded in the type VI-specific four-helix-bundle N-domain of VipB. Disaggregation of the tubules by the AAA+ protein ClpV and recycling of the VipA/B subunits are thereby limited to the contracted state.

  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. 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

  8. Structure and inhibition studies of a type II beta-carbonic anhydrase psCA3 from Pseudomonas aeruginosa.

    Science.gov (United States)

    Pinard, Melissa A; Lotlikar, Shalaka R; Boone, Christopher D; Vullo, Daniela; Supuran, Claudiu T; Patrauchan, Marianna A; McKenna, Robert

    2015-08-01

    Carbonic anhydrases (CAs) are metallo-enzymes that catalyze the reversible hydration of carbon dioxide into bicarbonate and a proton. The ?-class CAs (?-CAs) are expressed in prokaryotes, fungi, plants, and more recently have been isolated in some animals. The ?-CA class is divided into two subclasses, termed type I and II, defined by pH catalytic activity profile and active site structural configuration. Type I ?-CAs display catalytic activity over a broad pH range (6.5-9.0) with the active site zinc tetrahedrally coordinated by three amino acids and a hydroxide/water. In contrast, type II ?-CAs are catalytically active only at a pH 8 and higher where they adopt a functional active site configuration like that of type I. However, below pH 8 they are conformationally self-inactivated by the addition of a fourth amino acid coordinating the zinc and thereby displacing the zinc bound solvent. We have determined the structure of psCA3, a type II ?-CA, isolated from Pseudomonas aeruginosa (P. aeruginosa) PAO1 at pH 8.3, in its open active state to a resolution of 1.9 Å. The active site zinc is coordinated by Cys42, His98, Cys101 and a water/hydroxide molecule. P. aeruginosa is a multi-drug resistant bacterium and displays intrinsic resistance to most of the currently used antibiotics; therefore, there is a need for new antibacterial targets. Kinetic data confirm that psCA3 belongs to the type II subclass and that sulfamide, sulfamic acid, phenylboronic acid and phenylarsonic acid are micromolar inhibitors. In vivo studies identified that among six tested inhibitors representing sulfonamides, inorganic anions, and small molecules, acetazolamide has the most significant dose-dependent inhibitory effect on P. aeruginosa growth. PMID:26068018

  9. Iron-metallurgy products - Steels for structures and pressure equipment - grades and types. 8. ed.

    International Nuclear Information System (INIS)

    This book reviews french standards on structural steels and pressure equipment in iron-metallurgy products. Standards on concrete reinforcing bars, steel plates for boilers, pressure vessels and other uses as standards on flanges and steel forgings are examined

  10. Rock type discrimination and structural analysis with LANDSAT and Seasat data: San Rafael swell, Utah

    Science.gov (United States)

    Stewart, H. E.; Blom, R.; Abrams, M.; Daily, M.

    1980-01-01

    Satellite synthetic aperture radar (SAR) images is evaluated in terms of its geologic applications. The benchmark to which the SAR images are compared is LANDSAT, used both for structural and lithologic interpretations.

  11. 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.

  12. History or ecology? Substrate type as a major driver of patial genetic structure in Alpine plants

    OpenAIRE

    Alvarez, Nadir; Thiel-Egenter, Conny; Tribsch, Andreas; Holderegger, Rolf; Manel, Stéphanie; Schönswetter, Peter; Taberlet, Pierre; Brodbeck, Sabine; Gaudeul, Myriam; GIELLY, LUDOVIC; Küpfer, Philippe; Mansion, Guilhem; Negrini, Riccardo; Paun, Ovidiu; Pellecchia, Marco

    2009-01-01

    Climatic history and ecology are considered the most important factors moulding the spatial pattern of genetic diversity. With the advent of molecular markers, species' historical fates have been widely explored. However, it has remained speculative what role ecological factors have played in shaping spatial genetic structures within species. With an unprecedented, dense large-scale sampling and genome-screening, we tested how ecological factors have influenced the spatial genetic structures ...

  13. 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.

  14. A sodium gadolinium phosphate with two different types of tunnel structure: Synthesis, crystal structure, and optical properties of Na3GdP2O8

    International Nuclear Information System (INIS)

    A sodium gadolinium phosphate crystal, Na3GdP2O8, has been synthesized by a high-temperature solution reaction, and it exhibits a new structural family of the alkali-metal-rare-earth phosphate system. Although many compounds with formula M3LnP2O8 have been reported, but they were shown to be orthorhombic [R. Salmon, C. Parent, M. Vlasse, G. LeFlem, Mater. Res. Bull. 13 (1978) 439] rather than monoclinic as shown in this paper. Single-crystal X-ray diffraction analysis shows the structure to be monoclinic with space group C2/c and the cell parameters: a=27.55 (25), b=5.312 (4), c=13.935(11) A, ?=91.30(1)o, and V=2038.80 A3, Z=4. Its structure features a three-dimensional GdP2O83- anionic framework with two different types of interesting tunnels at where Na atoms are located by different manners. The framework is constructed by Gd polyhedra and isolated PO4 tetrahedra. It is different from the structure of K3NdP2O8 [R. Salmon, C. Parent, M. Vlasse, G. LeFlem, Mater. Res. Bull. 13 (1978) 439] with space group P21/m that shows only one type of tunnel. The emission spectrum and the absorption spectrum of the compound have been investigated. Additionally, the calculations of band structure, density of states, dielectric constants, and refractive indexes have been also performed with the density functional theory method. The obtained results tend to support the experimental data. - Graphical abstract: Projection of the structure of Na3GdP2O8 with a unit cell edge along the b-axis. The Na-O bonds are omitted for clarity

  15. Structure of the C-terminal head domain of the fowl adenovirus type 1 short fibre

    International Nuclear Information System (INIS)

    There are more than 100 known adenovirus serotypes, including 50 human serotypes. They can infect all 5 major vertebrate classes but only Aviadenovirus infecting birds and Mastadenovirus infecting mammals have been well studied. CELO (chicken embryo lethal orphan) adenovirus is responsible for mild respiratory pathologies in birds. Most studies on CELO virus have focussed on its genome sequence and organisation whereas the structural work on CELO proteins has only recently started. Contrary to most adenoviruses, the vertices of CELO virus reveal pentons with two fibres of different lengths. The distal parts (or head) of those fibres are involved in cellular receptor binding. Here we have determined the atomic structure of the short-fibre head of CELO (amino acids 201-410) at 2.0 A resolution. Despite low sequence identity, this structure is conserved compared to the other adenovirus fibre heads. We have used the existing CELO long-fibre head structure and the one we show here for a structure-based alignment of 11 known adenovirus fibre heads which was subsequently used for the construction of an evolutionary tree. Both the fibre head sequence and structural alignments suggest that enteric human group F adenovirus 41 (short fibre) is closer to the CELO fibre heads than the canine CAdV-2 fibre head, that lies closer to the human virus fibre heads

  16. 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 o...

  17. Structural evolution of early-type galaxies to z = 2.5 in CANDELS

    OpenAIRE

    Chang, Y-Y; van der Wel, A; Rix, H-W; Holden, B; Bell, EF; McGrath, EJ; Wuyts, S; Häussler, B; Barden, M; Faber, SM; M. Mozena; Ferguson, HC; Y. Guo; A. Galametz; Grogin, NA

    2013-01-01

    Projected axis ratio measurements of 880 early-type galaxies at redshifts 1 < z < 2.5 selected from CANDELS are used to reconstruct and model their intrinsic shapes. The sample is selected on the basis of multiple rest-frame colors to reflect low star-formation activity. We demonstrate that these galaxies as an ensemble are dust-poor and transparent and therefore likely have smooth light profiles, similar to visually classified early-type galaxies. Similar to their present-day counterparts, t...

  18. 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.

  19. Crystal Structure of the Michaelis Complex between Tissue-type Plasminogen Activator and Plasminogen Activators Inhibitor-1.

    Science.gov (United States)

    Gong, Lihu; Liu, Min; Zeng, Tu; Shi, Xiaoli; Yuan, Cai; Andreasen, Peter A; Huang, Mingdong

    2015-10-23

    Thrombosis is a leading cause of death worldwide. Recombinant tissue-type plasminogen activator (tPA) is the Food and Drug Administration-approved thrombolytic drug. tPA is rapidly inactivated by endogenous plasminogen activator inhibitor-1 (PAI-1). Engineering on tPA to reduce its inhibition by PAI-1 without compromising its thrombolytic effect is a continuous effort. Precise details, with atomic resolution, of the molecular interactions between tPA and PAI-1 remain unknown despite previous extensive studies. Here, we report the crystal structure of the tPA·PAI-1 Michaelis complex, which shows significant differences from the structure of its urokinase-type plasminogen activator analogue, the uPA·PAI-1 Michaelis complex. The PAI-1 reactive center loop adopts a unique kinked conformation. The structure provides detailed interactions between tPA 37- and 60-loops with PAI-1. On the tPA side, the S2 and S1? pockets open up to accommodate PAI-1. This study provides structural basis to understand the specificity of PAI-1 and to design newer generation of thrombolytic agents with reduced PAI-1 inactivation. PMID:26324706

  20. 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

  1. 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

  2. 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.

  3. On the prolongation structures of Petrov type III vacuum spacetime equations

    OpenAIRE

    E. O. Ifidon

    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.

  4. A correlation between redox behaviour of Fischer-type carbene complexes and their structure and reactivity.

    Czech Academy of Sciences Publication Activity Database

    Hoskovcová, I.; Dvo?ák, D.; Ludvík, Ji?í; Záliš, Stanislav

    Bratislava : Slovak Technical University Press, 2007 - (Melník, M.; Šima, J.; Tatarko, M.), s. 1-15 R&D Projects: GA ?R GA203/04/0487 Institutional research plan: CEZ:AV0Z40400503 Keywords : Fischer-type carbene complexes * correlation * electrochemical measurements Subject RIV: CG - Electrochemistry

  5. Structural Evolution of Early-type Galaxies to z=2.5 in CANDELS

    CERN Document Server

    Chang, Yu-Yen; Rix, Hans-Walter; Holden, Bradford; Bell, Eric F; McGrath, Elizabeth J; Wuyts, Stijn; Häußler, Boris; Barden, Marco; Faber, S M; Mozena, Mark; Ferguson, Henry C; Guo, Yicheng; Galametz, Audrey; Grogin, Norman A; Kocevski, Dale D; Koekemoer, Anton M; Dekel, Avishai; Huang, Kuang-Han; Hathi, Nimish P; Donley, Jennifer

    2013-01-01

    Projected axis ratio measurements of 880 early-type galaxies at redshifts 11 early-type galaxies show a variety of intrinsic shapes; even at a fixed mass, the projected axis ratio distributions cannot be explained by random projection of a set of galaxies with very similar intrinsic shapes. However, a two-population model for the intrinsic shapes, consisting of a triaxial, fairly round population, combined with a flat (c/a~0.3) oblate population, adequately describes the projected axis ratio distributions of both present-day and z>1 early-type galaxies. We find that the proportion of oblate vs. triaxial galaxies depends both on the galaxies stellar mass, and - at a given mass - on redshift. For present-day and z1 this trend is much weaker over the mass range explored here (10^101, compared to 0.20+-0.02 at z~0.1. In contrast, the oblate fraction among low-mass early-type galaxies (log(M*/M_sun)1 to 0.72+-0.06 at z=0. [Abridged

  6. Magnetic structure of the CeScSi-type RScGe compounds (R = Pr, Nd, Tb)

    Energy Technology Data Exchange (ETDEWEB)

    Manfrinetti, P. [Dipartimento di Chimica, Universita di Genova, Via Dodecaneso 31, 16146 Genova (Italy); Morozkin, A.V. [Department of Chemistry, Moscow State University, Leninskie Gory, House 1, Building 3, GSP-2, 119992 Moscow (Russian Federation)], E-mail: morozkin@general.chem.msu.ru; Isnard, O. [Institut Laue-Langevin, 6 Rue J. Horowitz, 38042 Grenoble (France); Laboratoire de Cristallographie du CNRS, Universite J. Fourier, BP166X, 38042 Grenoble (France); Henry, P. [Institut Laue-Langevin, 6 Rue J. Horowitz, 38042 Grenoble (France); Palenzona, A. [Dipartimento di Chimica, Universita di Genova, Via Dodecaneso 31, 16146 Genova (Italy)

    2008-02-14

    Subsequent magnetic transitions were recently reported for the CeScSi-type RScGe (R = rare earth) equiatomic intermetallic compounds. The compounds TbScGe and NdScGe order ferromagnetically at T{sub C} = 216 K and T{sub C} = 200 K, respectively whereas PrScGe orders antiferromagnetically at T{sub N} = 140 K. In addition, PrScGe demonstrates two other magnetic transitions at T{sub C1} = 88 K and T{sub C2} = 80 K in an applied field of 5 kOe. An investigation by neutron diffraction has been now carried out on these phases in an attempt to solve the magnetic structures corresponding to each ordering, and in this article the results obtained are reported. Below the Curie point, the magnetic structure of TbScGe and NdScGe is collinear ferromagnetic. The magnetic moment of Tb atoms coincides with the Z-axis of CeScSi-type unit cell (M{sub Tb} = 8.63{mu}{sub B} at 2 K), whereas the magnetic moment of Nd atoms has the {theta} = 52(2){sup o} angle with Z-axis (M{sub Nd} = 3.53(2){mu}{sub B} at 2 K). Below the Neel temperature, T{sub N} = 140 K the magnetic structure of PrScGe consists of antiferromagnetic (0 0 2) rare-earth double layers with magnetic moments of the rare earth atoms collinearly ordered. The magnetic moments of Pr atoms (M{sub Pr} = 1.72(3){mu}{sub B} at 100 K) have the {theta} = 62(2){sup o} angle with the Z-axis. Between T{sub C1} = 82 K and T{sub C2} = 62 K the conversion of the commensurate antiferromagnetic collinear type structure to the ferrimagnetic collinear type structure with propagation vector K = [0, 0, 1/2] was observed: the magnetic moments of Pr double layers became sine modulated along the Z-axis. Below T{sub C2} = 62 K the magnetic structure of PrScGe compound consists of ferrimagnetic (0 0 1/2) layers (amplitude of Pr magnetic moment M{sub Pr} = 3.31(9){mu}{sub B} at 5 K)

  7. STRUCTURAL EVOLUTION OF EARLY-TYPE GALAXIES TO z = 2.5 IN CANDELS

    International Nuclear Information System (INIS)

    Projected axis ratio measurements of 880 early-type galaxies at redshifts 1 1 early-type galaxies show a variety of intrinsic shapes; even at a fixed mass, the projected axis ratio distributions cannot be explained by the random projection of a set of galaxies with very similar intrinsic shapes. However, a two-population model for the intrinsic shapes, consisting of a triaxial, fairly round population, combined with a flat (c/a ? 0.3) oblate population, adequately describes the projected axis ratio distributions of both present-day and z > 1 early-type galaxies. We find that the proportion of oblate versus triaxial galaxies depends both on the galaxies' stellar mass, and—at a given mass—on redshift. For present-day and z 1, this trend is much weaker over the mass range explored here (1010 */M? 11), because the oblate fraction among massive (M* ? 1011 M?) was much higher in the past: 0.59 ± 0.10 at z > 1, compared to 0.20 ± 0.02 at z ? 0.1. When combined with previous findings that the number density and sizes of early-type galaxies substantially increase over the same redshift range, this can be explained by the gradual emergence of merger-produced elliptical galaxies, at the expense of the destruction of pre-existing disks that were common among their high-redshift progenitors. In contrast, the oblate fraction among low-mass early-type galaxies (log (M*/M?) 1 to 0.72 ± 0.06 at z = 0. We speculate that this lower incidence of disks at early cosmic times can be attributed to two factors: low-mass, star-forming progenitors at z > 1 were not settled into stable disks to the same degree as at later cosmic times, and the stripping of gas from star-forming disk galaxies in dense environments is an increasingly important process at lower redshifts

  8. Dynamic structural analysis of a head assembly for a large loop-type LMFBR

    International Nuclear Information System (INIS)

    An investigation is presented 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. The 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

  9. Design of an Improved Type Rotary Inductive Coupling Structure for Rotatable Contactless Power Transfer System

    Directory of Open Access Journals (Sweden)

    Lee Jia-You

    2015-01-01

    Full Text Available This paper is aimed at analyzing the rotary inductive coupling structure of contactless rotary transformer. The main feature of the proposed rotatable contactless power transfer system is which winding is coaxial-interlayered for improving the magnetic coupling capability. There is no ferrite core used in the secondary-side of the rotary inductive coupling structure, this helps to ease the exerted force that is stress by the secondary-side on spindle. In order to verify the feasibility of the proposed contactless power transfer system for rotary applications, an inductive powered rotary machinery and the control system have been integrated. The experimental results show that the maximum power transfer efficiency of the proposed rotary inductive coupling structure is about 94.8%. The maximum output power received in the load end is 1030 W with transmission efficiency of 88%.

  10. Structure of Glycerol Dehydratase Reactivase: A New Type of Molecular Chaperone

    Energy Technology Data Exchange (ETDEWEB)

    Liao, Der-Ing; Reiss, Lisa; Turner, Jr., Ivan; Dotson, Garry (Dupont)

    2010-03-08

    The function of glycerol dehydratase (GDH) reactivase is to remove damaged coenzyme B{sub 12} from GDH that has suffered mechanism-based inactivation. The structure of GDH reactivase from Klebsiella pneumoniae was determined at 2.4 {angstrom} resolution by the single isomorphous replacement with anomalous signal (SIR/AS) method. Each tetramer contains two elongated 63 kDa {alpha} subunits and two globular 14 kDa {beta} subunits. The {alpha} subunit contains structural features resembling both GroEL and Hsp70 groups of chaperones, and it appears chaperone like in its interactions with ATP. The fold of the {beta} subunit resembles that of the {beta} subunit of glycerol dehydratase, except that it lacks some coenzyme B12 binding elements. A hypothesis for the reactivation mechanism of reactivase is proposed based on these structural features.

  11. Peculiarities of crystalline structure and mechanism of disordering of anion sublattice in superionic conductors of LaF3 structural type

    International Nuclear Information System (INIS)

    On the basis of the analysis of LaF3 type lattice structure the physical process of disordering of tysonit type ionic crystals is considered in the region of superionic phase transitions. The correlation of cell movement of disordering sublattice ions with parameter dynamics of Raman scattering spectrum of these crystals is observed. The anomaly behaviour of Raman scattering frequencies and intensities of lines 370, 392 sm-1 (LaF3) and 304, 376, 404 sm-1 (PrF3) in three intervals: 160-180, 260-290, and 440-480 K is obtained. Two more high temperature ones are connected with anion sublattice disordering process in the region of phase transitions. Excessive scattering in the region 160-180 K is described by the change of oscillation state of fluoride ions in small displacements in splitted site positions with several potential minimums. It is shown in the framework of splitted sites model that the possibility of thermoactivational formation of interstitials which are comparable with the size of mobile ions is due to the peculiarities of the structure of tysonit type ionic crystals. (author)

  12. Structural Relaxation in Amorphous Alloys of Type FeSiB

    OpenAIRE

    Haneczok, G.; J. Rasek; Stoklosa, Z.; Zegrodnik, B.

    1996-01-01

    The Irreversible component of the structural relaxation in two ferromagnetic amorphous alloys Fe78Si9B13 and Fe78Si13B9 was examined by making use of mechanical spectroscopy and isothermal time instability measurements of shear modulus G(t) and magnetic permeability µ(t). It was shown that the first stage of the structural relaxation, attributed to the rearrangements of anisotropic atom pairs Si/B in the vicinity of free volumes takes place in the temperature range 300-500K with the mean acti...

  13. 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

  14. 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 ...

  15. 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.

  16. 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.

  17. Structural and Functional Insights into the Pilotin-Secretin Complex of the Type II Secretion System

    OpenAIRE

    Gu, Shuang; Rehman, Saima; Wang, Xiaohui; Shevchik, Vladimir E.; Pickersgill, Richard W.

    2012-01-01

    Gram-negative bacteria secrete virulence factors and assemble fibre structures on their cell surface using specialized secretion systems. Three of these, T2SS, T3SS and T4PS, are characterized by large outer membrane channels formed by proteins called secretins. Usually, a cognate lipoprotein pilot is essential for the assembly of the secretin in the outer membrane. The structures of the pilotins of the T3SS and T4PS have been described. However in the T2SS, the molecular mechanism of this pr...

  18. 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.

  19. SOLA inversions for the core structure of solar-type stars

    CERN Document Server

    Basu, S; Thompson, M J; Basu, Sarbani

    2001-01-01

    The Subtractive Optimally Localized Averages (SOLA) method, developed and extensively used in helioseismology, is applied to artificial data to obtain measures of the sound speed inside a solar-type star. In contrast to inversion methods which fit models to some aspect of the data, methods such as SOLA provide an honest assessment of what can truly be resolved using seismic data, without introducing additional assumptions such as that the space of admissible stellar models is small. The resulting measures obtained from SOLA inversion can subsequently be used to eliminate putative stellar models. Here we present results of experiments to test the reliability of SOLA inferences using solar models and models of solar-type stars.

  20. Harmonic structure of decametric Type III emission and radio wave group delay in the solar corona

    Science.gov (United States)

    Abranin, Eh. P.; Bazelyan, L. L.; Tsybko, Ya. G.; Abranin, Eh. P.; Bazelyan, L. L.; Tsybko, Ya. G.

    1993-08-01

    Solar observations with the UTR-2 decameter-wave radio telescope antenna, performed continuously at fixed frequencies from 25 to 10 MHz during Type III, IIIb-III noise storms from 1979 to 1984, have yielded new data on the frequency drift rates Delta(f)/Delta(tf) of numerous type IIIF, IIIFb, and IIIH(b) decameter radio bursts in several narrow bands Delta(f). The data confirm that the burst drift rates are virtually independent of the phase of the 11-yr solar activity cycle. Measurements of the drift time intervals for bursts drifting over narow bands (25-20 and 12.5-10 MHZ) separated by an octave prove the reliability of the radio burst harmonic classification in which there is a clear differentiation between the emission components coinciding with the fundamental and the second harmonic of the local plasma frequency.

  1. 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.

  2. 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…

  3. Genetic structure of the mating-type locus of Chlamydomonas reinhardtii.

    OpenAIRE

    Ferris, Patrick J; Armbrust, E Virginia; Goodenough, Ursula W

    2002-01-01

    Portions of the cloned mating-type (MT) loci (mt(+) and mt(-)) of Chlamydomonas reinhardtii, defined as the approximately 1-Mb domains of linkage group VI that are under recombinational suppression, were subjected to Northern analysis to elucidate their coding capacity. The four central rearranged segments of the loci were found to contain both housekeeping genes (expressed during several life-cycle stages) and mating-related genes, while the sequences unique to mt(+) or mt(-) carried genes e...

  4. Bipartite structure and functional independence of adenovirus type 5 packaging elements.

    OpenAIRE

    Schmid, S. I.; Hearing, P

    1997-01-01

    Selectivity and polarity of adenovirus type 5 DNA packaging are believed to be directed by an interaction of putative packaging factors with the cis-acting adenovirus packaging domain located within the genomic left end (nucleotides 194 to 380). In previous studies, this packaging domain was mutationally dissected into at least seven functional elements called A repeats. These elements, albeit redundant in function, exhibit differences in the ability to support viral packaging, with elements ...

  5. Amyloid in familial amyloidosis, Finnish type, is antigenically and structurally related to gelsolin.

    OpenAIRE

    Haltia, M.; Ghiso, J.; Prelli, F.; Gallo, G.; Kiuru, S.; Somer, H; Palo, J.; Frangione, B

    1990-01-01

    Immunohistochemical studies of six patients with familial amyloidosis, Finnish type, showed that their amyloid deposits did not react with polyclonal antibodies against the amyloid proteins of other, established forms of systemic or cerebral amyloidosis. However, strong immunoreactivity was observed with rabbit antiserum raised against a low molecular weight purified amyloid subunit isolated from one of the patients. This immunoreactivity was abolished by absorption with the low molecular wei...

  6. Structural and energetic determinants of adhesive binding specificity in type I cadherins

    OpenAIRE

    Vendome, Jeremie; Felsovalyi, Klara; Song, Hang; Yang, Zhongyu; Jin, Xiangshu; Brasch, Julia; Harrison, Oliver J; Ahlsen, Goran; Bahna, Fabiana; Kaczynska, Anna; Katsamba, Phinikoula S.; Edmond, Darwin; Hubbell, Wayne L.; Shapiro, Lawrence; Honig, Barry

    2014-01-01

    Type I cadherins comprise a family of cell–cell adhesion proteins that dimerize in a highly specific fashion. There are small differences in dimerization affinities among family members that are evolutionarily conserved and that have profound effects on cell-patterning behavior. There are few examples where the molecular origins of small affinity differences between closely related proteins have been explored in depth. We have brought an unusually broad range of technologies to bear on the pr...

  7. Biochemical and structural analysis of F-type ATP synthases and its subcomplexes

    OpenAIRE

    Matthies, Doreen

    2013-01-01

    ATP synthases are multi-subunit membrane enzymes, which utilize the energy stored in a transmembrane electrochemical ion gradient to produce adenosine-5´-triphosphate (ATP), the universal energy carrier in biological systems. Research on these important enzymes goes back more than 50 years and has produced innumerable studies. The F-type ATP synthase consists of two functionally distinct, but tightly coupled subcomplexes, the water-soluble F1 and the membrane-embedded Fo complex. In its simpl...

  8. Genetic diversity and population structure of 10 Chinese indigenous egg-type duck breeds assessed by microsatellite polymorphism.

    Science.gov (United States)

    Hui-Fang, Li; Wei-Tao, Song; Jing-Ting, Shu; Kuan-Wei, Chen; Wen-Qi, Zhu; Wei, Han; Wen-Juan, Xu

    2010-04-01

    The genetic structure and diversity of 10 Chinese indigenous egg-type duck breeds were investigated using 29 microsatellite markers. The total number of animals examined were 569, on average 57 animals per breed were selected. The microsatellite marker set analysed provided 177 alleles (mean 6.1 alleles per locus, ranging from 3 to 10). All populations showed high levels of heterozygosity with the lowest estimate of 0.539 for the Jinding ducks, and the highest 0.609 observed for Jingjiang partridge ducks. The global heterozygote deficit across all populations (FIT) amounted to -0.363. About 10% of the total genetic variability originated from differences among breeds, with all loci contributing significantly. An unrooted consensus tree was constructed using the NeighborNet tree based on the Reynold's genetic distance. The structure software was used to assess genetic clustering of these egg-type duck breeds. Clustering analysis provided an accurate representation of the current genetic relations among the breeds. An integrated analysis was undertaken to obtain information on the population dynamics in Chinese indigenous egg-type duck breeds, and to better determine the conservation priorities. PMID:20505248

  9. Stellar Kinematics and Structural Properties of Virgo Cluster Dwarf Early-Type Galaxies from the SMAKCED Project

    Science.gov (United States)

    Toloba, Elisa; Guhathakurta, Puragra; Peletier, Reynier; Boselli, Alessandro; Lisker, Thorsten; Emsellem, Eric; Simon, Joshua D.; van de Ven, Glenn; Smakced Collaboration

    2015-01-01

    We analyze the stellar kinematics of 39 dwarf early-type galaxies (dEs) in the Virgo cluster. This is the largest survey conducted so far on spatially resolved kinematics of dEs. This sample is representative of the early-type population in the absolute magnitude range -19.0 Virgo cluster rotate significantly faster than fast rotators in the inner parts of the cluster. Moreover, 10 out of the 11 slow rotators are located in the inner Mpc of the cluster. The fast rotators contain subtle disky structures that are visible in high-pass filtered optical images, while the slow rotators do not exhibit these structures. In addition, two of the dEs have kinematically decoupled cores and four more have emission partially filling in the Balmer absorption lines. These properties suggest that Virgo cluster dEs may have originated from late-type star-forming galaxies that were transformed by the environment after their infall into the cluster. The correlation between the specific angular momentum and the clustercentric distance can be explained by a scenario where low luminosity star-forming galaxies fall into the cluster, their gas is rapidly removed by ram pressure stripping, although some of it can be retained in their core, their star-formation is quenched but their stellar kinematics are preserved. After a long time in the cluster and several passes through its center, the galaxies are heated up and transformed into slow rotating dEs.

  10. Genetic diversity and population structure of 10 Chinese indigenous egg-type duck breeds assessed by microsatellite polymorphism

    Indian Academy of Sciences (India)

    Li Hui-Fang; Song Wei-Tao; Shu Jing-Ting; Chen Kuan-Wei; Zhu Wen-Qi; Han Wei; Xu Wen-Juan

    2010-04-01

    The genetic structure and diversity of 10 Chinese indigenous egg-type duck breeds were investigated using 29 microsatellite markers. The total number of animals examined were 569, on average 57 animals per breed were selected. The microsatellite marker set analysed provided 177 alleles (mean 6.1 alleles per locus, ranging from 3 to 10). All populations showed high levels of heterozygosity with the lowest estimate of 0.539 for the Jinding ducks, and the highest 0.609 observed for Jingjiang partridge ducks. The global heterozygote deficit across all populations ($F_{\\text{IT}}$) amounted to $-0.363$. About 10% of the total genetic variability originated from differences among breeds, with all loci contributing significantly. An unrooted consensus tree was constructed using the NeighborNet tree based on the Reynold’s genetic distance. The structure software was used to assess genetic clustering of these egg-type duck breeds. Clustering analysis provided an accurate representation of the current genetic relations among the breeds. An integrated analysis was undertaken to obtain information on the population dynamics in Chinese indigenous egg-type duck breeds, and to better determine the conservation priorities.

  11. 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)

  12. STRUCTURAL EVOLUTION OF EARLY-TYPE GALAXIES TO z = 2.5 IN CANDELS

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Yu-Yen; Van der Wel, Arjen; Rix, Hans-Walter [Max-Planck Institut fuer Astronomie, Koenigstuhl 17, D-69117 Heidelberg (Germany); Holden, Bradford; Faber, S. M.; Mozena, Mark; Guo Yicheng; Kocevski, Dale D. [UCO/Lick Observatory, Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA 95064 (United States); Bell, Eric F. [Department of Astronomy, University of Michigan, 500 Church Street, Ann Arbor, MI 48109 (United States); McGrath, Elizabeth J. [Department of Physics and Astronomy, Colby College, Waterville, ME 04901 (United States); Wuyts, Stijn [Max-Planck-Institut fuer Extraterrestrische Physik, Postfach 1312, Giessenbachstr., D-85741 Garching (Germany); Haeussler, Boris [Schools of Physics and Astronomy, University of Nottingham, University Park, Nottingham NG7 2RD (United Kingdom); Barden, Marco [Institute of Astro- and Particle Physics, University of Innsbruck, Technikerstrasse 25, A-6020 Innsbruck (Austria); Ferguson, Henry C.; Grogin, Norman A.; Koekemoer, Anton M.; Huang, Kuang-Han [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Galametz, Audrey [INAF-Osservatorio di Roma, Via Frascati 33, I-00040 Monteporzio (Italy); Dekel, Avishai [Racah Institute of Physics, Hebrew University, Jerusalem 91904 (Israel); Hathi, Nimish P., E-mail: chang@mpia.de [Observatories of the Carnegie Institution for Science, Pasadena, CA (United States); and others

    2013-08-20

    Projected axis ratio measurements of 880 early-type galaxies at redshifts 1 < z < 2.5 selected from CANDELS are used to reconstruct and model their intrinsic shapes. The sample is selected on the basis of multiple rest-frame colors to reflect low star-formation activity. We demonstrate that these galaxies as an ensemble are dust-poor and transparent and therefore likely have smooth light profiles, similar to visually classified early-type galaxies. Similar to their present-day counterparts, the z > 1 early-type galaxies show a variety of intrinsic shapes; even at a fixed mass, the projected axis ratio distributions cannot be explained by the random projection of a set of galaxies with very similar intrinsic shapes. However, a two-population model for the intrinsic shapes, consisting of a triaxial, fairly round population, combined with a flat (c/a {approx} 0.3) oblate population, adequately describes the projected axis ratio distributions of both present-day and z > 1 early-type galaxies. We find that the proportion of oblate versus triaxial galaxies depends both on the galaxies' stellar mass, and-at a given mass-on redshift. For present-day and z < 1 early-type galaxies the oblate fraction strongly depends on galaxy mass. At z > 1, this trend is much weaker over the mass range explored here (10{sup 10} < M{sub *}/M{sub Sun} < 10{sup 11}), because the oblate fraction among massive (M{sub *} {approx} 10{sup 11} M{sub Sun }) was much higher in the past: 0.59 {+-} 0.10 at z > 1, compared to 0.20 {+-} 0.02 at z {approx} 0.1. When combined with previous findings that the number density and sizes of early-type galaxies substantially increase over the same redshift range, this can be explained by the gradual emergence of merger-produced elliptical galaxies, at the expense of the destruction of pre-existing disks that were common among their high-redshift progenitors. In contrast, the oblate fraction among low-mass early-type galaxies (log (M{sub *}/M{sub Sun }) < 10.5) increased toward the present, from z = 0 to 0.38 {+-} 0.11 at z > 1 to 0.72 {+-} 0.06 at z = 0. We speculate that this lower incidence of disks at early cosmic times can be attributed to two factors: low-mass, star-forming progenitors at z > 1 were not settled into stable disks to the same degree as at later cosmic times, and the stripping of gas from star-forming disk galaxies in dense environments is an increasingly important process at lower redshifts.

  13. 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.

  14. 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.

  15. Structural studies of P-type ATPase-ligand complexes using an X-ray free-electron laser

    DEFF Research Database (Denmark)

    Bublitz, Maike; Nass, Karol

    2015-01-01

    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.

  16. A Study of the Relationship between Type of Organizational Structure of University and Departmental Social Capital with Students\\\\\\' Academic Satisfaction at Shiraz University

    Directory of Open Access Journals (Sweden)

    jafar torkzadeh

    2014-04-01

    Through the investigation of the relationship between university’s types of organizational structure with students’ academic satisfaction, it was concluded that organizational structure type is a significant predictor of students' satisfaction. According to this finding, an enabling structure has a positive and significant relationship with students’ academic satisfaction (01/0? P ? 42/0 = ?.. The results of this study are in line with the findings of Shorts (1994 b, Kara (2004 and Kayzr and Saymsyk (2005, emphasizing that there is a significant and positive correlation between an enabling organizational structure and increase in students' level of academic satisfaction. If the structure of the university will be enabling due to it

  17. Influence of hydrogenation on the structural and magnetic properties of compounds based on cerium and crystallizing in the tetragonal CeFeSi-type structure

    OpenAIRE

    Chevalier, Bernard; Pasturel, Mathieu; Bobet, Jean-Louis; Isnard, Olivier

    2005-01-01

    The hydrogen absorption properties of CeMnGe, CeFeSi and CeCoX (X=Si and Ge) have been investigated. Neutron powder diffraction performed on deuteride CeCoGeD indicates that D-atoms are inserted in the pseudo-tetrahedral interstices [Ce4] of the tetragonal CeFeSi-type structure of this compound. Magnetization and electrical resistivity measurements reveal that the hydrogenation of: (i) CeCoSi and CeCoGe leads to the transition antiferromagnet?spin fluctuation behaviour; (ii) CeMnGe suppress t...

  18. 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.

  19. The structural determination of fluorite-type oxygen excess uranium oxides using EXAFS spectroscopy

    Science.gov (United States)

    Jones, Deborah J.; Roziere, Jacques; Allen, Geoffrey C.; Tempest, Paul A.

    1986-06-01

    Extended x-ray absorption fine structure (EXAFS) spectroscopy has been carried out at 77 K at the uranium LIII edge for UO2, ?-U3O7, and U4O9 with the aim of determining the structure of these highly defective (oxygen excess) uranium oxide phases, which are of industrial importance. Use has been made of a difference Fourier technique for U3O7, in which the EXAFS of a perfect lattice model is subtracted. U-O bond lengths calculated from the remaining EXAFS signal, assumed to result only from interstitial oxygens, have been used to determine the atomic coordinates of these interstitials. The analysis of EXAFS data in terms of coordination number has allowed an insight into the defect aggregate arrangement of oxygens in U3O7 and U4O9. Furthermore, EXAFS data indicate that the uranium sublattice is perturbed by the incorporation of additional oxygen atoms.

  20. 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...

  1. 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 ...

  2. '' Smoluchowski Type '' Equations for Modelling of Air Separation by Membranes with Various Structure

    International Nuclear Information System (INIS)

    The problem of a membrane air separation in the presence of a magnetic field, is considered. Paramagnetism of oxygen and diamagnetic behaviour of nitrogen form the basis for air separation. A new concept of polymer membranes filled with neodymium powder and magnetized ('' magnetic membranes ''), was applied. The Smoluchowski equation for oxygen, and simple diffusion equation for nitrogen behaviour in the air have been used. Multifractal analysis of structure and morphology of membranes were applied to optical microscopy images. (author)

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

    OpenAIRE

    Pastan Ira; Patankar Manish S; Hahn Yoonsoo; Sathyanarayana Bangalore K; Lee Byungkook

    2009-01-01

    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,...

  4. Simulation and optimization of n-type PERL silicon solar cell structure

    OpenAIRE

    William R. Taube; Kumar, A.

    2011-01-01

    Optimization of structure and process parameters of PERL (Passivated Emitter Rear Locally Diffused) silicon solar cell using SILVACO software package has been carried out. PERL single junction silicon solar cells are reported by researchers to have high efficiency (~ 20-25 %) and are promising for further improvement. Optimization is based on process and device simulation in SILVACO software package and integrating a Response Surface Methodology for optimal solution. Optimization of texture d...

  5. Tree type and forest management effects on the structure of strem wood following wilfires

    OpenAIRE

    Vaz, Pedro G.; Warren, Dana R.; Pinto, Paulo; Merten, Eric Christopher; Robinson, Christopher T.; Rego, Francisco Castro

    2011-01-01

    Wildfires are an increasingly common disturbance influencing wood recruitment to streams, and thereby affecting their physical and biological condition. Mediterranean countries such as Portugal, where more than 25% of the land area has burned since 1990, are ideal areas to study impacts of wildfire effects on streams. We evaluated the physical structure of 2206 downed wood pieces (DWP) across 27 first- to third-order streams in central Portugal, all of which had experienced recent...

  6. 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...

  7. LHD type proton-boron reactor and the control of its peripheral potential structure

    Energy Technology Data Exchange (ETDEWEB)

    Matsumoto, Yutaka; Nagaura, Tatsuhiko; Itoh, Yasuyoshi; Oikawa, Shun-ichi [Graduate School of Engineering, Hokkaido Univ., Sapporo, Hokkaido (Japan); Watanabe, Tsuguhiro [National Inst. for Fusion Science, Toki, Gifu (Japan)

    2001-04-01

    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{sup -11} B fusion relevant energy. Numerical results also show that the LHD magnetic configuration can confine the high energy {sup 4}He well. An active peripheral potential control method and an active {sup 4}He ash exhaust scheme are discussed. (author)

  8. Vitamin D, carotid intima-media thickness, and bone structure in patients with type 2 diabetes

    DEFF Research Database (Denmark)

    Winckler, Karoline; Tarnow, Lise; Christensen, Louise Lundby; Almdal, Thomas Peter; Wiinberg, Niels; Eiken, Pia; Boesgaard, Trine Welløv

    2015-01-01

    Despite aggressive treatment of cardiovascular disease (CVD) risk factors individuals with type 2 diabetes (T2D) still have increased risk of cardiovascular morbidity and mortality. The primary aim of this study was to examine the cross-sectional association between total (25(OH)D) and risk of CVD in patients with T2D. Secondary objective was to examine the association between 25(OH)D and bone health. A Danish cohort of patients with T2D participating in a randomised clinical trial were analysed...

  9. Kinetics of B2- and D03-type ordering and formation of domain structures in Fe Al alloys

    Science.gov (United States)

    Oguma, R.; Matsumura, S.; Eguchi, T.

    2008-07-01

    Time-dependent Ginzburg-Landau (TDGL) formulation has been developed for the ordering processes of B2 and D03 types in binary alloy systems. In the formulation, three order parameters are defined in order to describe the state of order. Equivalent variants of B2 and D03 structures are distinguished using these order parameters. The mean-field free energy is defined in the form of a Landau-type expansion using the order parameters and a composition parameter. Interface energies due to local variations in the degrees of order and concentration are given with a gradient square approximation. Kinetic equations are derived from the Ginzburg-Landau-type potential in order to describe the time-evolutions of the order parameters and the concentration. Numerical simulations of the kinetic equations have been performed for B2- and D03-type ordering as well as concurrent ordering and phase separation to disordered A2+D03. The simulated results provide a good reproduction of the formation processes of B2 and D03 ordered domains in an Fe3Al alloy.

  10. 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.

  11. Direct band gap electroluminescence from bulk germanium at room temperature using an asymmetric fin type metal/germanium/metal structure

    International Nuclear Information System (INIS)

    We demonstrated direct band gap (DBG) electroluminescence (EL) at room temperature from n-type bulk germanium (Ge) using a fin type asymmetric lateral metal/Ge/metal structure with TiN/Ge and HfGe/Ge contacts, which was fabricated using a low temperature (<400?°C) process. Small electron and hole barrier heights were obtained for TiN/Ge and HfGe/Ge contacts, respectively. DBG EL spectrum peaked at 1.55??m was clearly observed even at a small current density of 2.2??A/?m. Superlinear increase in EL intensity was also observed with increasing current density, due to superlinear increase in population of elections in direct conduction band. The efficiency of hole injection was also clarified

  12. 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.

  13. 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.

  14. 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.

  15. A Near-infrared Census of the Multicomponent Stellar Structure of Early-type Dwarf Galaxies in the Virgo Cluster

    Science.gov (United States)

    Janz, J.; Laurikainen, E.; Lisker, T.; Salo, H.; Peletier, R. F.; Niemi, S.-M.; Toloba, E.; Hensler, G.; Falcón-Barroso, J.; Boselli, A.; den Brok, M.; Hansson, K. S. A.; Meyer, H. T.; Ry?, A.; Paudel, S.

    2014-05-01

    The fraction of star-forming to quiescent dwarf galaxies varies from almost infinity in the field to zero in the centers of rich galaxy clusters. What is causing this pronounced morphology-density relation? What do quiescent dwarf galaxies look like when studied in detail, and what conclusions can be drawn about their formation mechanism? Here we study a nearly magnitude-complete sample (-19 Virgo cluster early types with deep near-infrared images from the SMAKCED project. We fit two-dimensional models with optional inner and outer components, as well as bar and lens components (in ~15% of the galaxies), to the galaxy images. While a single Sérsic function may approximate the overall galaxy structure, it does not entirely capture the light distribution of two-thirds of our galaxies, for which multicomponent models provide a better fit. This fraction of complex galaxies shows a strong dependence on luminosity, being larger for brighter objects. We analyze the global and component-specific photometric scaling relations of early-type dwarf galaxies and discuss similarities with bright early and late types. The dwarfs' global galaxy parameters show scaling relations that are similar to those of bright disk galaxies. The inner components are mostly fitted with Sérsic n values close to 1. At a given magnitude, they are systematically larger than the bulges of spirals, suggesting that they are not ordinary bulges. We argue that the multicomponent structures in early-type dwarfs are mostly a phenomenon inherent to the disks and may indeed stem from environmental processing. Based on observations collected at the European Organisation for Astronomical Research in the Southern Hemisphere, Chile, under program IDs 064.N-0288 and 085.B-0919.

  16. A near-infrared census of the multicomponent stellar structure of early-type dwarf galaxies in the Virgo cluster

    International Nuclear Information System (INIS)

    The fraction of star-forming to quiescent dwarf galaxies varies from almost infinity in the field to zero in the centers of rich galaxy clusters. What is causing this pronounced morphology-density relation? What do quiescent dwarf galaxies look like when studied in detail, and what conclusions can be drawn about their formation mechanism? Here we study a nearly magnitude-complete sample (–19 < Mr < –16 mag) of 121 Virgo cluster early types with deep near-infrared images from the SMAKCED project. We fit two-dimensional models with optional inner and outer components, as well as bar and lens components (in ?15% of the galaxies), to the galaxy images. While a single Sérsic function may approximate the overall galaxy structure, it does not entirely capture the light distribution of two-thirds of our galaxies, for which multicomponent models provide a better fit. This fraction of complex galaxies shows a strong dependence on luminosity, being larger for brighter objects. We analyze the global and component-specific photometric scaling relations of early-type dwarf galaxies and discuss similarities with bright early and late types. The dwarfs' global galaxy parameters show scaling relations that are similar to those of bright disk galaxies. The inner components are mostly fitted with Sérsic n values close to 1. At a given magnitude, they are systematically larger than the bulges of spirals, suggesting that they are not ordinary bulges. We argue that the multicomponent structures in early-type dwarfs are mostly a phenomenon inherent to the disks and may indeed stem from environmental processing.

  17. A near-infrared census of the multicomponent stellar structure of early-type dwarf galaxies in the Virgo cluster

    Energy Technology Data Exchange (ETDEWEB)

    Janz, J.; Laurikainen, E.; Salo, H. [Division of Astronomy, Department of Physics, P.O. Box 3000, FI-90014 University of Oulu (Finland); Lisker, T.; Hansson, K. S. A.; Meyer, H. T.; Paudel, S. [Astronomisches Rechen-Institut, Zentrum für Astronomie der Universität Heidelberg, Mönchhofstraße 12-14, D-69120 Heidelberg (Germany); Peletier, R. F.; Den Brok, M. [Kapteyn Astronomical Institute, University of Groningen, P.O. Box 800, 9700 AV Groningen (Netherlands); Niemi, S.-M. [Mullard Space Science Laboratory, University College London, Holmbury St. Mary, Dorking, Surrey RH5 6NT (United Kingdom); Toloba, E. [UCO/Lick Observatory, University of California, Santa Cruz, 1156 High Street, Santa Cruz, CA 95064 (United States); Hensler, G. [University of Vienna, Department of Astrophysics, Türkenschanzstraße 17, 1180 Vienna (Austria); Falcón-Barroso, J.; Ry?, A. [Instituto de Astrofísica de Canarias, Vía Láctea s/n, La Laguna, Tenerife (Spain); Boselli, A., E-mail: jjanz@ari.uni-heidelberg.de [CNRS, LAM (Laboratoire d' Astrophysique de Marseille) UMR 7326, Aix Marseille Université, F-13388 Marseille (France)

    2014-05-10

    The fraction of star-forming to quiescent dwarf galaxies varies from almost infinity in the field to zero in the centers of rich galaxy clusters. What is causing this pronounced morphology-density relation? What do quiescent dwarf galaxies look like when studied in detail, and what conclusions can be drawn about their formation mechanism? Here we study a nearly magnitude-complete sample (–19 < M{sub r} < –16 mag) of 121 Virgo cluster early types with deep near-infrared images from the SMAKCED project. We fit two-dimensional models with optional inner and outer components, as well as bar and lens components (in ?15% of the galaxies), to the galaxy images. While a single Sérsic function may approximate the overall galaxy structure, it does not entirely capture the light distribution of two-thirds of our galaxies, for which multicomponent models provide a better fit. This fraction of complex galaxies shows a strong dependence on luminosity, being larger for brighter objects. We analyze the global and component-specific photometric scaling relations of early-type dwarf galaxies and discuss similarities with bright early and late types. The dwarfs' global galaxy parameters show scaling relations that are similar to those of bright disk galaxies. The inner components are mostly fitted with Sérsic n values close to 1. At a given magnitude, they are systematically larger than the bulges of spirals, suggesting that they are not ordinary bulges. We argue that the multicomponent structures in early-type dwarfs are mostly a phenomenon inherent to the disks and may indeed stem from environmental processing.

  18. Structure-Function Relationship of SW-AT-1, a Serpin-Type Protease Inhibitor in Silkworm

    OpenAIRE

    Cheng LIU; Han, Yue; Chen, Xi; Zhang, Wei

    2014-01-01

    Although SW-AT-1, a serpin-type trypsin inhibitor from silkworm (Bombyx mori), was identified in previous study, its structure-function relationship has not been studied. In this study, SW-AT-1 was cloned from the body wall of silkworm and expressed in E. coli. rSW-AT-1 inhibited both trypsin and chymotrypsin in a concentration-dependent manner. The association rate constant for rSW-AT-1 and trypsin is 1.31×10?5 M?1s?1, for rSW-AT-1 and chymotrpsin is 2.85×10?6 M?1s?1. Circular dichroism (CD)...

  19. Structural characterization of Ni and Ni/Ti ohmic contact on n-type 4H-SiC

    Energy Technology Data Exchange (ETDEWEB)

    Siad, M., E-mail: siadmenouar@yahoo.fr [Centre de Recherche Nucleaire d' Alger, 02 Bd Frantz Fanon (Algeria); Abdesselam, M. [USTHB, Faculte de Physique, BP 32, El Alia, Bab Ezzouar (Algeria); Souami, N. [Centre de Recherche Nucleaire d' Alger, 02 Bd Frantz Fanon (Algeria); Chami, A.C. [USTHB, Faculte de Physique, BP 32, El Alia, Bab Ezzouar (Algeria)

    2011-10-01

    In this study, we report on the structural characterization of Ni layer and Ni/Ti bilayer contacts on n-type 4H-SiC. The resulting Ni-silicides and the redistribution of carbon, after annealing at 950 deg. C, in the Ni/SiC and the Ni/Ti/SiC contacts are particularly studied by Rutherford Backscattering Spectrometry (RBS) at E{sub {alpha}} = 3.2 MeV, nuclear reaction analysis (NRA) at E{sub d} = 1 MeV, scanning electron microscopy (SEM) and Energy Dispersive X-ray Spectrometry (EDS) techniques.

  20. Recognition of the Different Structural Forms of the Capsid Protein Determines the Outcome following Infection with Porcine Circovirus Type 2

    OpenAIRE

    Trible, Benjamin R.; Suddith, Andrew W.; Kerrigan, Maureen A.; Cino-Ozuna, Ada G.; Hesse, Richard A.; Rowland, Raymond R. R.

    2012-01-01

    Porcine circovirus type 2 (PCV2) capsid protein (CP) is the only protein necessary for the formation of the virion capsid, and recombinant CP spontaneously forms virus-like particles (VLPs). Located within a single CP subunit is an immunodominant epitope consisting of residues 169 to 180 [CP(169–180)], which is exposed on the surface of the subunit, but, in the structural context of the VLP, the epitope is buried and inaccessible to antibody. High levels of anti-CP(169–180) activity are assoc...

  1. 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

  2. Structural characterization of rat ventricular tissue exposed to the smoke of two types of waterpipe

    Directory of Open Access Journals (Sweden)

    Wajdy Al-Awaida

    2015-10-01

    Full Text Available Objective(s:this study focused on the effect of waterpipe smoke exposure toxicity on the structure of albino rat’s ventricular tissue and their recovery. Materials and Methods: Albino rats were divided into three groups: control, flavored, and unflavored. The control group was exposed to normal air while the flavored and unflavored groups were exposed to waterpipe smoke for a period of 90 days. Each group was followed by a period of 90 days of fresh air exposure. Following each period, the ventricular tissue was removed for biochemical and histopathological studies. Results:The ventricular tissues of waterpipe exposed rats showed some degree of separation between cardiac muscle fibers, infiltration of lymphocytes, and congestion of blood vessel. Also, thin cross sections of ventricular cells revealed pleomorphic mitochondria with partially disrupted cristae, partial disruption of the myofibrils, and deposited toxic materials. The unflavored waterpipe has more deleterious effects on heart ventricular tissues than the flavored one. Waterpipe smoke didn't induce apoptosis in the ventricular tissue. We also found very high levels of plasma thiocyanate after exposure to smoke in the flavored and unflavored groups, while the control group showed no increase. After the recovery period, those tissues showed partial recovery. Conclusion: Waterpipe smoke induces structural changes in the heart ventricle tissues, causing a negative impact on the capacity of the cardiac muscle for pumping blood and may lead to heart attack due to accumulation of free radicals and tissue inflammation. Cessation of smoking is important in returning most of these changes to their normal structure.

  3. 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.

  4. The type I interferon receptor: structure, function, and evolution of a family business.

    Science.gov (United States)

    Mogensen, K E; Lewerenz, M; Reboul, J; Lutfalla, G; Uzé, G

    1999-10-01

    Recent results indicate that coherent models of how multiple interferons (IFN) are recognized and signal selectively through a common receptor are now feasible. A proposal is made that the IFN receptor, with its subunits IFNAR-1 and IFNAR-2, presents two separate ligand binding sites, and this double structure is both necessary and sufficient to ensure that the different IFN are recognized and can act selectively. The key feature is the duplication of the extracellular domain of the IFNAR-1 subunit and the configurational geometry that this imposes on the intracellular domains of the receptor subunits and their associated tyrosine kinases. PMID:10547147

  5. 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.

  6. The crystal structure of staphylococcal enterotoxin type D reveals Zn2+-mediated homodimerization.

    OpenAIRE

    Sundström, M; Abrahmsén, L; Antonsson, P; Mehindate, K; Mourad, W; Dohlsten, M.

    1996-01-01

    Bacterial superantigens, including the staphylococcal enterotoxins, are the most potent activators of T cells known and have been suggested as a causative factor in Gram-positive shock in humans. Staphylococcal enterotoxin D (SED) is dependent upon Zn2+ for high affinity interactions with MHC class II molecules and thus SED was co-crystallized with Zn2+. The crystal structure of SED has been determined in two different space groups, at 2.3 and 3.0 A resolution respectively. The three-dimensio...

  7. Structural basis for type VI secreted peptidoglycan dl-endopeptidase function, specificity and neutralization in Serratia marcescens

    International Nuclear Information System (INIS)

    Crystal structures of type VI secretion system-associated immunity proteins, a peptidoglycan endopeptidase and a complex of the endopeptidase and its cognate immunity protein are reported together with assays of endopeptidase activity and functional assessment. Some Gram-negative bacteria target their competitors by exploiting the type VI secretion system to extrude toxic effector proteins. To prevent self-harm, these bacteria also produce highly specific immunity proteins that neutralize these antagonistic effectors. Here, the peptidoglycan endopeptidase specificity of two type VI secretion-system-associated effectors from Serratia marcescens is characterized. These small secreted proteins, Ssp1 and Ssp2, cleave between ?-d-glutamic acid and l-meso-diaminopimelic acid with different specificities. Ssp2 degrades the acceptor part of cross-linked tetratetrapeptides. Ssp1 displays greater promiscuity and cleaves monomeric tripeptides, tetrapeptides and pentapeptides and dimeric tetratetra and tetrapenta muropeptides on both the acceptor and donor strands. Functional assays confirm the identity of a catalytic cysteine in these endopeptidases and crystal structures provide information on the structure–activity relationships of Ssp1 and, by comparison, of related effectors. Functional assays also reveal that neutralization of these effectors by their cognate immunity proteins, which are called resistance-associated proteins (Raps), contributes an essential role to cell fitness. The structures of two immunity proteins, Rap1a and Rap2a, responsible for the neutralization of Ssp1 and Ssp2-like endopeptidases, respectively, revealed two distinct folds, with that of Rap1a not having previously been observed. The structure of the Ssp1–Rap1a complex revealed a tightly bound heteromeric assembly with two effector molecules flanking a Rap1a dimer. A highly effective steric block of the Ssp1 active site forms the basis of effector neutralization. Comparisons with Ssp2–Rap2a orthologues suggest that the specificity of these immunity proteins for neutralizing effectors is fold-dependent and that in cases where the fold is conserved sequence differences contribute to the specificity of effector–immunity protein interactions

  8. Seismic Experimental Study on New-Type Composite Exterior Wallboard with Integrated Structural Function and Insulation

    Directory of Open Access Journals (Sweden)

    Shaochun Ma

    2015-06-01

    Full Text Available In order to evaluate the seismic performance of new-type composite exterior wallboard, a total of six exterior and interior wallboards were incorporated in the experiment of seismic performance. Seismic performance such as the stress process, damage mode, hysteresis and skeleton curve, load-carrying and ductility coefficient, damping and energy dissipation, stiffness degradation as well as material strain of the exterior wallboards were analyzed with emphasis and compared with interior wallboards. Results of the experiment and analysis showed that both interior and exterior wallboards exhibited outstanding seismic performance. Due to the existence of insulation layer and externally bonded single gypsum board, the capacity of elastoplastic deformation and seismic energy dissipation of the exterior wallboards was improved and each seismic performance indicator of the exterior wallboards outperformed the interior wallboards.

  9. A quantitative metallographic assessment of structural degradation of Type 316 stainless steel during creep-fatigue

    International Nuclear Information System (INIS)

    Optical and scanning electron microscopy have revealed the existence of grain boundary cavities in a series of specimens which had been cyclically deformed in the strain range +-0.25% with hold times ranging from 0 to 1000 min. The way in which these defects increase in size and number has been measured and found to correlate with the creep strain accumulated during the hold periods. A further observation is that a critical amount of deformation is required before either fatigue or creep type damage is nucleated. These observations lead to an alternative method to the currently accepted linear damage summation rule for estimating a lower bound of the creep-fatigue endurance. (author)

  10. Structure and elevated temperature properties of Type 308 stainless steel weld metal with varying ferrite contents

    International Nuclear Information System (INIS)

    The as-deposited microstructure, creep and tensile properties at 649 C (1200 F), and fracture behavior of shielded metal-arc Type 308 stainless steel welds having nominal ferrite contents from 0 to 15% were investigated. The ferrite phase morphology varied from isolated patches in nominally 0% ferrite welds to a nearly continuous phase in nominally 15% ferrite welds in metallographic studies. Low ductility creep failures occurred when extensive interphase cracking occurred at austenite--sigma phase boundaries (i.e., for welds with high initial ferrite content tested under low stress). The fraction of creep test time before third-stage creep was usually less than 0.3 for specimens that exhibited high ductility

  11. Structure of EspB from the ESX-1 type VII secretion system and insights into its export mechanism.

    Science.gov (United States)

    Solomonson, Matthew; Setiaputra, Dheva; Makepeace, Karl A T; Lameignere, Emilie; Petrotchenko, Evgeniy V; Conrady, Deborah G; Bergeron, Julien R; Vuckovic, Marija; DiMaio, Frank; Borchers, Christoph H; Yip, Calvin K; Strynadka, Natalie C J

    2015-03-01

    Mycobacterium tuberculosis (Mtb) uses the ESX-1 type VII secretion system to export virulence proteins across its lipid-rich cell wall, which helps permeabilize the host's macrophage phagosomal membrane, facilitating the escape and cell-to-cell spread of Mtb. ESX-1 membranolytic activity depends on a set of specialized secreted Esp proteins, the structure and specific roles of which are not currently understood. Here, we report the X-ray and electron microscopic structures of the ESX-1-secreted EspB. We demonstrate that EspB adopts a PE/PPE-like fold that mediates oligomerization with apparent heptameric symmetry, generating a barrel-shaped structure with a central pore that we propose contributes to the macrophage killing functions of EspB. Our structural data also reveal unexpected direct interactions between the EspB bipartite secretion signal sequence elements that form a unified aromatic surface. These findings provide insight into how specialized proteins encoded within the ESX-1 locus are targeted for secretion, and for the first time indicate an oligomerization-dependent role for Esp virulence factors. PMID:25684576

  12. Effect of heat treatment on the phase composition, structure and magnetic properties of M-type barium hexaferrite

    International Nuclear Information System (INIS)

    Effect of the heat treatment of carbonate-hydroxide precipitates on the phase composition, structure and magnetic properties of M-type barium hexaferrite has been investigated using the M?ssbauer spectroscopy, X-ray phase analysis and magnetic measurements. The distribution of Fe3+ ions over structural sites of barium hexaferrite with different degree of ferritizations has been defined. The conditions of single-domain behavior of barium hexaferrite nanoparticles in the magnetic field have been discussed. Obtained results explain the formation of magnetic structure during the synthesis of barium hexaferrite. This information could further be used for optimizing conditions for synthesis of nanosized barium hexaferrite with high-level properties. - Highlights: • In the T=973–1273 K range, BaFe12O19 (BHF) phase are formed from precipitates. • Fe3+ ions prefer to occupy 12k,2a,2b (at 1073 K) and 4f1,4f2 (at 1273 K) sites. • The most favorable magnetic structure for high Ms forms at T=1073 K. • The presence of 5–10% of ?-Fe2O3 phase can improve magnetic properties of BHF

  13. Direct methods and residue type specific isotope labeling in NMR structure determination and model-driven sequential assignment

    International Nuclear Information System (INIS)

    Direct methods in NMR based structure determination start from an unassigned ensemble of unconnected gaseous hydrogen atoms. Under favorable conditions they can produce low resolution structures of proteins. Usually a prohibitively large number of NOEs is required, to solve a protein structure ab-initio, but even with a much smaller set of distance restraints low resolution models can be obtained which resemble a protein fold. One problem is that at such low resolution and in the absence of a force field it is impossible to distinguish the correct protein fold from its mirror image. In a hybrid approach these ambiguous models have the potential to aid in the process of sequential backbone chemical shift assignment when 13C? and 13C' shifts are not available for sensitivity reasons. Regardless of the overall fold they enhance the information content of the NOE spectra. These, combined with residue specific labeling and minimal triple-resonance data using 13C? connectivity can provide almost complete sequential assignment. Strategies for residue type specific labeling with customized isotope labeling patterns are of great advantage in this context. Furthermore, this approach is to some extent error-tolerant with respect to data incompleteness, limited precision of the peak picking, and structural errors caused by misassignment of NOEs

  14. 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)

  15. Structural Basis for Platelet Collagen Responses by the Immune-type Receptor Glycoprotein VI

    Energy Technology Data Exchange (ETDEWEB)

    Horii,K.; Kahn, M.; Herr, A.

    2006-01-01

    Activation of circulating platelets by exposed vessel wall collagen is a primary step in the pathogenesis of heart attack and stroke, and drugs to block platelet activation have successfully reduced cardiovascular morbidity and mortality. In humans and mice, collagen activation of platelets is mediated by glycoprotein VI (GPVI), a receptor that is homologous to immune receptors but bears little sequence similarity to known matrix protein adhesion receptors. Here we present the crystal structure of the collagen-binding domain of human GPVI and characterize its interaction with a collagen-related peptide. Like related immune receptors, GPVI contains 2 immunoglobulin-like domains arranged in a perpendicular orientation. Significantly, GPVI forms a back-to-back dimer in the crystal, an arrangement that could explain data previously obtained from cell-surface GPVI inhibition studies. Docking algorithms identify 2 parallel grooves on the GPVI dimer surface as collagen-binding sites, and the orientation and spacing of these grooves precisely match the dimensions of an intact collagen fiber. These findings provide a structural basis for the ability of an immunetype receptor to generate signaling responses to collagen and for the development of GPVI inhibitors as new therapies for human cardiovascular disease.

  16. Structure diversity in three forest types of north-eastern Thailand (Sakaerat Reserve, Pak Tong Chai

    Directory of Open Access Journals (Sweden)

    Malaisse F.

    1998-01-01

    Full Text Available 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 area and the tree density. The species richness increases with the passage from the DDF, the most open environment, to the DDFwf, the most densely wooded. By these tree density and basal area, the DDF (602 trees/ha at DBH ³ 5 cm, 14.2 m2/ha and the DEF (992 trees/ha at DBH ³ 5 cm, 29.0 m2/ha studied belong to the typical tropical ecosytems of southeast Asia. The man-made fires and anarchic forest exploitations are a danger for the stability of these different ecosystems.

  17. Crystal structure analyses of the pyrochlore- and fluorite-type Zd2Gd2O7 and anti-phase domain structure

    International Nuclear Information System (INIS)

    The detailed structure investigations of Zr2Gd2O7 with pyrochlore- and fluorite-type structures have been carried out by X-ray single crystal method at room temperature. The bond distance between cations and oxide ions versus the site population for cations reasonably support that the fluorite phase is made up of the structure with microdomains of the pyrochlore. Sharp fundamental and diffuse superstructure reflections of the pyrochlore and interpreted assuming that anti-phase domain boundaries lie parallel to the 211 and that domain sizes are not uniform. It should be proposed that the layers composed of the 48f site oxide ions are anti-phase boundaries. The probability density function maps and effective one-particle potentials of the pyrochlore structure reveal that the magnitudes of anharmonic thermal motions for the 48f site oxide ions are anti-phase boundaries. The probability density function maps and effective one-particle potentials of the pyrochlore structure reveal that the magnitudes of anharmonic thermal motions for the 48f site oxide ions are large toward the unoccupied 8b site. Compared to the s-pyrochlore phase (with sharp superstructure reflections), the 48f site oxide ions of the d-pyrochlore (with sharp superstructure reflections), the 48f site oxide ions of the d-pyrochlore (with diffuse superstructure reflections) and fluorite phases have larger temperature factors and gentler potential curves. This is due to that the anti-phase domains are coherent each other and that their electron density distributions are the averages of individual domains. (author). 18 refs.; 10 figs.; 3 tabs

  18. Structural changes in brass-type intermetallic compounds by neutron action

    Energy Technology Data Exchange (ETDEWEB)

    Denisova, A.A.; Kofanov, B.A.; Pyatiletova, N.A. (AN Kazakhskoj SSR, Alma-Ata (Kazakhstan). Inst. Yadernoj Fiziki)

    1992-05-01

    Using X-ray diffraction, we have studied stoichiometric [gamma]-phase alloys of the Cu-Zn, Cu-Cd, Ni-Zn, and Mn-Zn systems that had been neutron-irradiated to fluences of 8.8 x 10[sup 18] - 6.3 x 10[sup 23] neutron m[sup -2] (E > 2.35 MeV, 80[sup o]C) and then subjected to isochronal annealings up to submelting temperatures. We found that under irradiation all these isostructural intermetallic compounds change over into a heterogeneous state and that the stability of the latter depends on the structural details of the elements in the compound. The dependence on the fluence of the lattice parameters of the matrices and irradiation-induced phases in the alloys was determined. (author).

  19. Evaluation of structural integrity and heat exchange efficiency for dimpled tube type EGR cooler

    International Nuclear Information System (INIS)

    Most of vehicle manufacturers have applied Exhaust Gas Recirculation (EGR) system to the development of diesel engines in order to obtain the high thermal efficiency without NOX and Particulate Matter (PM) emitted from the engine. EGR system, which reflow a cooled exhaust gas from vehicles burning diesel as fuel to a combustion chamber of engine, has been used to solve this problem. In order to confirm the safety of the EGR system, finite element analysis was carried out. The safety of EGR system against temperature variation in the shell and tubes was evaluated through the thermal and structural analysis, and the modal analysis using ANSYS was also performed. Finally, the performance of EGR system was verified through the experiment and numerical simulation using effectiveness-NTU method. Program for the estimation of the heat exchange efficiency of the EGR system with regard to the dimpled tube shape was developed

  20. Performance of a novel type of electrolyte-supported solid oxide fuel cell with honeycomb structure

    Energy Technology Data Exchange (ETDEWEB)

    Ruiz-Morales, Juan Carlos; Savvin, Stanislav N.; Nunez, Pedro [Departmento de Quimica Inorganica, Universidad de La Laguna, 38200 Tenerife (Spain); Marrero-Lopez, David [Departamento de Fisica Aplicada I, Universidad de Malaga, 29071 Malaga (Spain); Pena-Martinez, Juan; Canales-Vazquez, Jesus [Instituto de Energias Renovables-Universidad de Castilla la Mancha, 02006 Albacete (Spain); Roa, Joan Josep; Segarra, Merce [DIOPMA, Departamento de Ciencia de los Materiales e Ing. Metalurgica, 08028 Barcelona (Spain)

    2010-01-15

    A novel design, alternative to the conventional electrolyte-supported solid oxide fuel cell (SOFC) is presented. In this new design, a honeycomb-electrolyte is fabricated from hexagonal cells, providing high mechanical strength to the whole structure and supporting the thin layer used as electrolyte of a SOFC. This new design allows a reduction of {proportional_to}70% of the electrolyte material and it renders modest performances over 320 mW cm{sup -2} but high volumetric power densities, i.e. 1.22 W cm{sup -3} under pure CH{sub 4} at 900 C, with a high OCV of 1.13 V, using the standard Ni-YSZ cermet as anode, Pt as cathode material and air as the oxidant gas. (author)

  1. Fatigue Behavior of a Box-Type Welded Structure of Hydraulic Support Used in Coal Mine

    Directory of Open Access Journals (Sweden)

    Xiaohui Zhao

    2015-09-01

    Full Text Available Hydraulic support is the main supporting equipment of the coal mining systems, and they are usually subjected to fatigue failure under the high dynamic load. The fracture positions are generally at welded joints where there is a serious stress concentration. In order to investigate and further improve the fatigue strength of hydraulic support, the present work first located the possible position where fatigue failure occurs through finite element analysis, and then fatigue tests were carried out on the different forms of welded joints for the dangerous parts. Finally, Fatigue strength-life (S-N curves and fracture mechanism were studied. This research will provide a theoretical reference for the fatigue design of welded structures for hydraulic support.

  2. On the molecular and electronic structure of matrine-type alkaloids

    International Nuclear Information System (INIS)

    A systematic study of the molecular and electronic structure of the eight possible members in the trans-matrine series and of two dehydro-derivatives, sophocarpine and sophoramine, has been performed. According to density functional theory (DFT) calculations these alkaloids exhibit a variety of form and junction of the four six-membered rings and all but sophocarpine have a strong preference for one conformation. Sophocarpine is predicted to have a marked conformational flexibility at the lactamic nitrogen and to exist as a mixture of two nearly isoenergetic conformers (C/D-trans and -cis) in the gas phase or solution. The theoretical predictions are consistent with the available X-ray experimental results as well as IR and NMR evidence. The absolute configuration of the preferred conformer of each compound has been established theoretically and corroborated with the specific optical rotation calculated at the sodium D line. The conformational equilibrium of sophocarpine has also been supported by this physical property. The computed gas-phase proton affinity of matrines indicates a basicity comparable to that of other polycyclic proton sponges. The lowest-energy electronic transitions have been characterized by time-dependent DFT calculations as mainly due to excitations spanning the frontier orbitals ?(NCO), n(O), n(Naminic), and ?*(CO). The electronic structures have also been studied by measuring and calculating significant features of the NMR and photoelectron spectra. In particular, a representative set of NMR chemical shifts and nuclear spin-spin coupling constants, obtained with DFT formalisms, compares favourably with experiment. Notably, the stereoelectronic hyperconjugative effects on ??(Heq/Hax) and ?1 J(CHeq/CHax) of the >N-CO- groups is correctly accounted for by the theoretical results. Based on ab initio outer valence Green's function calculations, a reliable description of the uppermost bands in the photoelectron spectra has been advanced. The splitting and sequence of the ionization energies reflect a complex interaction of the n and ? chromophores

  3. A new type structural catalytic carrier and system for selective oxidation of gaseous hydrocarbons

    Directory of Open Access Journals (Sweden)

    Zbigniew Najzarek

    2004-10-01

    Full Text Available Over the last few years the micro-method achievements have emerged as the high-throughputexperimentation approaches to complex processes in which development of heterogeneous catalysts forindustrial purposes has become a challenge. Also the selective oxidation of gaseous alkanes should bedirected towards green and profitable synthesis which involve complex processes. Namely, intermediates ofthe high activation-temperature oxidation react faster than the alkane substrate and burn up especially athot-spots due to temperature rise and catalyst deactivation. Moreover, uniformity between alkane functionalgroups complicate the oxidation scheme with parallel side-reactions. However, in this case the well-known,adverse effect of unsatisfactory comparability of the micro-method with those obtained in the conventionalreactors becomes a problem that permanently follows a limitation of heat-transfer across catalytic grains.The limitation causes non-isothermal conditions and then the hot-spot effects which give rise to theincomparability. Hence, to data n-butane selective oxidation to maleic anhydride on VPO phases is the onlysuch a synthesis applied on the industrial scale owing to both stability of the quasi-aromatic product andselectivity of the catalyst acting as a stoichiometric agent that for this reactivity is used only in grain forms.Accordingly, a short contact-time , selective catalytic system could bring about the comparability and thenselectivity. Therefore, a new catalytic system of thin-layer VPO catalyst on structured carriers with enhancedheat-transfer efficiency was elaborated in this work, and optimized towards n-butane selective oxidation ona semi-industrial scale. The selective oxidation on that catalyst was controlled with the intrinsic processparameters and reactant properties. On the other hand, it is well-known that isothermal micro-processes arecontrolled with the same parameters and properties. In a consequence, the thin-layer catalyst wassupported on structured gauze for research on the selective oxidation of gaseous alkanesunder the comparability conditions.

  4. Effect of different doping on the structural, morphological and magnetic properties for Cu doped nanoscale spinel type ferrites

    International Nuclear Information System (INIS)

    CuxM1?xFe2O4 (M=Co, Mn and Ni; x=0.0, 0.6 and 1.0) spinel type ferrite nanoparticles have been synthesized by cetyltrimethylammonium bromide (CTAB) assisted hydrothermal route using NaOH solution. The purity, structural characterization and magnetic properties have been investigated using the scanning electron microscopy, x-ray diffraction analysis and a quantum design vibrating sample magnetometer depending on the temperature. The scanning electron microscopy imaging exhibits very powerful aspect. The average size of composite nanoparticles for all samples was determined. Diameter of the samples is synthesized in nanoscale. The x-ray diffraction results have indicated that these samples are high phase purity, crystalline and inverse spinel ferrites. The temperature evolution of the magnetic properties and different doping effects for the samples have been observed. The pseudo spin-valve behavior has been showed for Cu0.6Co0.4Fe2O4 and CoFe2O4 samples. These samples can be considered as promising materials for magnetic recording media and electromagnetic absorbing technologies applications. - Highlights: • The powders doped with transition elements demonstrated spinel type and crystal structures. • The coercivity of nanoparticles in this work increases with decreasing temperature. • In this study, nanoparticles exhibit pseudo spin-valve characteristics. • These examples of magnetic recording, electromagnetic absorption and radar technologies will be used

  5. "Waterspout" as a result of the Ocean's Skeletal Structures and a Special Type of Atmospheric Aerosol Dusty Plasma

    CERN Document Server

    Rantsev-Kartinov, V A

    2004-01-01

    An analysis of databases of photographic images of ocean's surface, taken from various altitudes and for various types of rough ocean surface, revealed the presence of an ocean's skeletal structures (OSS). We make a stress on the phenomenon of OSS's blocks in the form of vertically oriented floating cylinders (VFC) because here we suggest the hypothesis that the VFC is a stimulator of initial phase of the "waterspout" phenomenon (WS). An analysis of the fine structure of VFC suggests the OSS to be a carrier/source of major electrodynamical properties of initial phase of every WS. This implies that the main body of WS may be interpreted as a special type of atmospheric aerosol dusty plasma. In such a framework, the WS is considered as the long-lived filament, being formed in electric discharge in the presence of electric and magnetic fields in the course of electric breakdown between the cloud and ocean surface. In this case the charged water aerosol (formed by means of VFC's capillaries in the presence of ver...

  6. Molecular dynamics studies on the NMR structures of rabbit prion protein wild-type and mutants: surface electrostatic charge distributions

    CERN Document Server

    Zhang, Jiapu

    2014-01-01

    Prion is a misfolded protein found in mammals that causes infectious diseases of the nervous system in humans and animals. Prion diseases are invariably fatal and highly infectious neurodegenerative diseases that affect a wide variety of mammalian species such as sheep and goats, cattle, deer, elk and humans etc. Recent studies have shown that rabbits have a low susceptibility to be infected by prion diseases with respect to other animals including humans. The present study employs molecular dynamics (MD) means to unravel the mechanism of rabbit prion proteins (RaPrPC) based on the recently available rabbit NMR structures (of the wild-type and its two mutants of two surface residues). The electrostatic charge distributions on the protein surface are the focus when analysing the MD trajectories. It is found that we can conclude that surface electrostatic charge distributions indeed contribute to the structural stability of wild-type RaPrPC; this may be useful for the medicinal treatment of prion diseases.

  7. Exact solutions for free vibration of shear-type structures with arbitrary distribution of mass or stiffness.

    Science.gov (United States)

    Li, Q S

    2001-10-01

    In this paper, shear-type structures such as frame buildings, etc., are treated as nonuniform shear beams (one-dimensional systems) in free-vibration analysis. The expression for describing the distribution of shear stiffness of a shear beam is arbitrary, and the distribution of mass is expressed as a functional relation with the distribution of shear stiffness, and vice versa. Using appropriate functional transformation, the governing differential equations for free vibration of nonuniform shear beams are reduced to Bessel's equations or ordinary differential equations with constant coefficients for several functional relations. Thus, classes of exact solutions for free vibrations of the shear beam with arbitrary distribution of stiffness or mass are obtained. The effect of taper on natural frequencies of nonuniform beams is investigated. Numerical examples show that the calculated natural frequencies and mode shapes of shear-type structures are in good agreement with the field measured data and those determined by the finite-element method and Ritz method. PMID:11681376

  8. Synthesis and electronic structure of proton-type partially substituted birnessite by period-four transition metal

    International Nuclear Information System (INIS)

    Highlights: ? Partial metal substitutions of birnessite result in three types of crystal structure. ? Rhombohedral, monoclinic and hexagonal phase emerged in the substituted birnessite. ? The electrical conductivity decreased by substitution of transition metal for Mn. ? Partially substitution by Fe, Co and Ni poses splitting of crystal field for MnO6. -- Abstract: Partially substituted proton-type birnessite were prepared by solid state reaction and their structures were refined. The formed birnessite with no substitution is identified to rhombohedral phase. In the case of substitution treatment by V and Cr for Mn, birnessite phase was not formed. On substituting Fe, hexagonal phase increased with increase of the amount of the Fe. For Co and Ni-substitution, monoclinic phase emerged at substitution ratio of around 0.37 and 0.02, respectively. For the substitution of Cu, only the monoclinic birnessite formed irrespective of the ratio. The electric conductivity of the partially substituted birnessites was examined at room temperature. The general trend is lower conductivity with increasing ratio of contained substituents. On several mol% of the substitution by Ni and Cu, the conductivity slightly increased. From DOS calculation of these compounds, the partially substitution for Mn by Fe, Co and Ni in the birnessite poses splitting of crystal field to emerge new bands at around -1 and +1 eV by Mn(IV) 3d orbital.

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

    Directory of Open Access Journals (Sweden)

    G. Matula

    2007-10-01

    Full Text Available 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 Metallurgy it was found of that density of sintered samples depend on reinforced particles, temperatures and atmosphere of sintering. Increasing of sintering temperature increase the density of sintering samples. Moreover the sintering under N2-10%H2 atmosphere produce samples with higher quality than using argon atmosphere and prevent of surface oxidation during sintering.Practical implications: The modern methods of powder metallurgy gives the possibility to manufacturing tools materials on the basis of high speed-steel which characterised very good properties with their final shape.Originality/value: In the paper the manufacturing by modern PM methods of tool materials on basis of high speed-steel manufactured carried out in order to improve the structure and properties of tool materials and to produce tools with their final shape.

  10. Structural change and power factor enhancement of thermoelectric p-type films

    International Nuclear Information System (INIS)

    By sputter-deposition thin films of the thermoelectric effective p-type compound semiconductor (Bi0.15Sb0.85)2Te3 were prepared. For the first time a distinct increase of the electrical conductivity s was observed after heating of the as-deposited films and afterwards cooling. For the enlightenment of this typical behavior, which seems to be similar found for phase change materials consisting of (Ge, Sb, Te)-alloys, also the Seebeck (S) and the Hall coefficient were measured. It was established that the increase of the electrical conductivity is not connected with an expected decrease of the Seebeck coefficient, because the charge carrier density is reduced but at the same time the hole mobility is increasing. Corresponding analytical investigations by XRD, EDX, and REM shows that besides a grain growth in the polycrystalline films a Te-rich phase appears after the heat treatment. The increase of the electrical conductivity at nearly unchanged Seebeck coefficient can be exploited for the enhancement of the film power factor (S2s). This is important for the efficiency of thermoelectric thin films devices as miniaturized coolers, generators, and sensors. Nevertheless for a quantitative interpretation of the presented new experimental results further investigations and theoretical considerations are required

  11. Vitamin D, carotid intima-media thickness, and bone structure in patients with type 2 diabetes

    DEFF Research Database (Denmark)

    Winckler, Karoline; Tarnow, Lise

    2015-01-01

    Despite aggressive treatment of cardiovascular disease (CVD) risk factors individuals with type 2 diabetes (T2D) still have increased risk of cardiovascular morbidity and mortality. The primary aim of this study was to examine the cross-sectional association between total (25(OH)D) and risk of CVD in patients with T2D. Secondary objective was to examine the association between 25(OH)D and bone health. A Danish cohort of patients with T2D participating in a randomised clinical trial were analysed. In total 415 patients (68 % men, age 60±9 years (mean±SD), duration of diabetes 12±6 years), including 294 patients (71%) treated with insulin. Carotid intima-media thickness (IMT) and arterial stiffness (carotid artery distensibility coefficient (DC) and Young's elastic modulus (YEM)) were measured by ultrasound scan as indicators of CVD. Bone health was assessed by bone mineral density (BMD) and trabecular bone score (TBS) measured by Dual energy X-ray absorptiometry (DXA). In this cohort, 214 patients (52 %) were vitamin D deficient (25(OH)D 0.3) or bone health (P > 0.6) after adjustment for CVD risk factors. In conclusion, 25(OH)D status was not associated with carotid IMT, arterial stiffness or bone health in this cohort of patients with T2D. To explore these associations and the association with other biomarkers further, multicentre studies with large numbers of patients are required.

  12. Structural properties of discs and bulges of early-type galaxies

    CERN Document Server

    De Jong, R S; Davies, R L; Saglia, R P; Burstein, D; Colless, M; McMahan, R; Wegner, G; Jong, Roelof S. de; Simard, Luc; Davies, Roger L.; Burstein, David; Colless, Matthew; Mahan, Robert Mc; Wegner, Gary

    2004-01-01

    We have used the EFAR sample of galaxies to study the light distributions of early-type galaxies. We decompose the 2D light distribution of the galaxies in a flattened spheroidal component with a Sersic radial light profile and an inclined disc component with an exponential light profile. We show that the brightest, bulge dominated elliptical galaxies have a fairly broad distribution in the Sersic profile shape parameter n_B, with a median of about 3.7 and a sigma of ~0.9. Other galaxies have smaller n_B values, meaning that spheroids are in general less concentrated than the n_B=4 de Vaucouleurs-law profile. The results of our light decompositions are robust, even though without kinematic information we cannot prove that the spheroids and discs are really pressure- and rotation-supported stellar systems. If we assume that the detected spheroids and discs are indeed separate components, we can draw the following conclusions: 1) the spheroid and disc scale sizes are correlated; 2) bulge-to-total luminosity rat...

  13. Structure design and experimental appraisal of the drag force type vertical axis wind turbine

    International Nuclear Information System (INIS)

    Experiments were conducted to estimate the performance of drag force type vertical axis wind turbine with an opening-shutting rotor. It was operated by the difference in drag force generated on both sides of the blades. The rotational speed was measured by a tachometer in a wind tunnel and the tunnel wind speed was measured by using a pitot-static tube and a micro manometer. The performance test for a prototype was accomplished by calculating power, power coefficient, torque coefficient from the measurement of torque and rpm by a dynamometer controller. Various design parameters, such as the number of blades(B), blade aspect ratio(W/R), angle of blades(?) and drag coefficient acting on a blade, were considered for optimal conditions. At the experiment of miniature model, maximum efficiency was found at N=15, ?=60 .deg. and W/R=0.32. The measured test variables were power, torque, rotational speed, and wind speeds. The data presented are in the form of power and torque coefficients as a function of tip-speed ratio V/U. Maximum power was found in case of ?=0.33, when the power and torque coefficient were 0.14 and 0.37 respectively. Comparing model test with prototype test, similarity law by advance ratio for vertical axis wind turbine was confirmed

  14. Dechannelling and the nature of defect structures in natural type Ia diamonds

    International Nuclear Information System (INIS)

    The dechannelling of 1 MeV protons in a set of natural type Ia diamonds containing relatively large quantities of nitrogen (up to 0.2%) is found to be enhanced over that found in the best diamonds. The dechannelling cross-section of the defects producing this additional dechannelling has been determined on the basis of the single scattering model and is found to be correlated with specific features in the infra-red absorption spectra of the diamonds which are known to be associated with the presence of platelets precipitated on (100) planes and also with features associated with the so-called B form of nitrogen. The energy dependence of the dechannellingg cross-section has been measured over a range of energies from 1 to 9.8 MeV, and is found to vary as Esub(-1/4). The dechannelling in a diamond containing only B nitrogen has also been measured. The dechannelling is interpreted as being produced by the platelets, and a simple model has been used to analyse the results. Estimates of the areal density of the platelets are in agreement with values found by other workers. A relation between the infra-red absorption coefficient and the platelet areal density is derived. The relationship between the platelets and the B form of nitrogen is discussed in the light of the correlations found. (orig.)

  15. Single crystal growth, structural characteristics and magnetic properties of chromium substituted M-type ferrites

    Science.gov (United States)

    Shlyk, L.; Vinnik, D. A.; Zherebtsov, D. A.; Hu, Z.; Kuo, C.-Y.; Chang, C.-F.; Lin, H.-J.; Yang, L.-Y.; Semisalova, A. S.; Perov, N. S.; Langer, T.; Pöttgen, R.; Nemrava, S.; Niewa, R.

    2015-12-01

    Two different types of fluxes, namely sodium based and chloride based fluxes were used to grow Cr substituted barium and strontium hexaferrite ferrite crystals, (Sr,Ba)Fe12 - xCrxO19 at comparatively low temperatures of about 1300 °C. The sodium based flux led to growth of larger crystals up to 5 mm, but with only minor Cr contents x ? 0.07. From the chloride based flux the obtained Cr contents are significantly higher with x = 5.7 (Sr) and x = 3.4 (Ba), however, crystals reach only sizes in the sub-mm range. X-ray absorption spectroscopy data support exclusively isovalent substitution of Fe3+ by Cr3+ even for very low Cr contents. 57Fe Mößbauer spectroscopy reveals Cr to preferentially occupy the six-fold by oxygen coordinated site at 12k and, to a lower degree, 2a and 4f2 in space group P63/mmc. All characteristic magnetic properties drop upon Cr substitution, e. g., the Curie temperature from 728 K for pure BaFe12O19 to 465 K for BaFe8.6Cr3.4O19, the saturation magnetization from 71 emu/g to 29.7 emu/g and the coercive field from 363 Oe to 45 Oe.

  16. Structural, microstructural and vibrational characterization of apatite-type lanthanum silicates prepared by mechanical milling

    International Nuclear Information System (INIS)

    Apatite-type lanthanum silicates have been successfully prepared at room temperature by dry milling hexagonal A-La2O3 and either amorphous or low cristobalite SiO2. Milling a stochiometric mixture of these chemicals in a planetary ball mill with a moderate rotating disc speed (350 rpm), allows the formation of the target phase after only 3 h although longer milling times are needed to eliminate all SiO2 and La2O3 traces. Thus, the mechanically activated chemical reaction proceeds faster when using amorphous silica instead of low cristobalite as silicon source and pure phases are obtained after only 9 and 18 h, respectively. As obtained powder phases are not amorphous and show an XRD pattern as well as IR and Raman bands characteristic of the lanthanum silicate. The domain size of the as-prepared phases varies gradually with the temperature of post-milling thermal treatment with activation energies of about 26(8) and 52(10) kJ mol-1 K-1 for the apatites obtained from amorphous silica and low-cristobalite, respectively. These values suggest crystallite growth to be favored when using amorphous silica as reactant

  17. Tailoring structural, optical and magnetic properties of spinel type cobalt oxide (Co3O4) by manganese doping

    International Nuclear Information System (INIS)

    To study the effects of manganese doping on structural, optical and magnetic properties of spinel type cobalt oxide (Co3O4) system, manganese ions were doped at different concentrations (5–20%) using co-precipitation method. Crystalline nature and phase purity of the prepared materials were investigated using XRD, FTIR and XPS measurements. Manganese ions played a major role in reducing crystallite size and introducing macro/micro-strains in the doped compounds. Surface morphology of the materials examined using FESEM images confirmed the role played by manganese ion in restraining particle growth. Manganese doping was further confirmed using EDS and XPS elemental analysis. From the XPS studies, manganese concentration in the doped samples were identified to be close to the initial doping percentage (MnxCo3?xO4; x=4.61%, 8.25%, 14.13% and 18.10%). Presence of three types of manganese ions was revealed from the XPS study. Pair of absorption bands centered at 440 nm and 720 nm characteristic of spinel type cobalt oxide was observed for all the prepared materials. Micro- and macro-strains induced by manganese doping have created localized density of states reducing band energy gaps in the doped materials. Mn2+ ions replacing Co2+ ions in the tetrahedral site have enhanced the weak ferromagnetism observed for pristine cobalt oxide. Saturation magnetization, coercivity and remanent magnetization was found to increase with Mn2+ concentration

  18. A novel land use approach for assessment of human health: The relationship between urban structure types and cardiorespiratory disease risk.

    Science.gov (United States)

    Réquia Júnior, Weeberb João; Roig, Henrique Llacer; Koutrakis, Petros

    2015-12-01

    Extensive evidence shows that in addition to lifestyle factors, environmental aspects are an important risk factor for human health. Numerous approaches have been used to estimate the relationship between environment and health. For example, the urban characteristics, especially the types of land use, are considered a potential proxy indicator to evaluate risk of disease. Although several studies have used land use variables to assess human health, none of them has used the concept of Urban Morphology by Urban Structure Types (USTs) as indicators of land use. The aim of this study was to assess the relationship between USTs and cardiorespiratory disease risks in the Federal District, Brazil. Toward this end, we used a quantile regression model to estimate risk. We used 21 types of UST. Income and population density were used as covariates in our sensitivity analysis. Our analysis showed an association between cardiorespiratory diseases risk and 10 UST variables (1 related to rural area, 6 related to residential area, 1 recreational area, 1 public area and 1 commercial area). Our findings suggest that the conventional land use method may be missing important information about the effect of land use on human health. The use of USTs can be an approach to complement the conventional method. This should be of interest to policy makers in order to enhance public health policies and to create future strategies in terms of urban planning, land use and environmental health. PMID:26458022

  19. An Active Heater Control Concept to Meet IXO Type Mirror Module Thermal-Structural Distortion Requirement

    Science.gov (United States)

    Choi, Michael

    2013-01-01

    Flight mirror assemblies (FMAs) of large telescopes, such as the International X-ray Observatory (IXO), have very stringent thermal-structural distortion requirements. The spatial temperature gradient requirement within a FMA could be as small as 0.05 C. Con ventionally, heaters and thermistors are attached to the stray light baffle (SLB), and centralized heater controllers (i.e., heater controller boards located in a large electronics box) are used. Due to the large number of heater harnesses, accommodating and routing them is extremely difficult. The total harness length/mass is very large. This innovation uses a thermally conductive pre-collimator to accommodate heaters and a distributed heater controller approach. It minimizes the harness length and mass, and reduces the problem of routing and accommodating them. Heaters and thermistors are attached to a short (4.67 cm) aluminum portion of the pre-collimator, which is thermally coupled to the SLB. Heaters, which have a very small heater power density, and thermistors are attached to the exterior of all the mirror module walls. The major portion (23.4 cm) of the pre-collimator for the middle and outer modules is made of thin, non-conductive material. It minimizes the view factors from the FMA and heated portion of the precollimator to space. It also minimizes heat conduction from one end of the FMA to the other. Small and multi-channel heater controllers, which have adjustable set points and internal redundancy, are used. They are mounted to the mechanical support structure members adjacent to each module. The IXO FMA, which is 3.3 m in diameter, is an example of a large telescope. If the heater controller boards are centralized, routing and accommodating heater harnesses is extremely difficult. This innovation has the following advantages. It minimizes the length/mass of the heater harness between the heater controllers and heater circuits. It reduces the problem of routing and accommodating the harness on the FMA. It reduces the risk of X-ray attenuation caused by the heater harness. Its adjustable set point capability eliminates the need for survival heater circuits. The operating mode heater circuits can also be used as survival heater circuits. In the non-operating mode, a lower set point is used.

  20. Elucidating Functional Aspects of P-type ATPases : Structural Studies of SERCA1a and LpCopA

    DEFF Research Database (Denmark)

    Autzen, Henriette Elisabeth

    2015-01-01

    P-type ATPases are proteins that act to maintain ion homeostasis and electrochemical gradients through the translocation of cations across cell membranes. Underscoring their significance in humans, dysfunction of the ATPases can lead to crucial diseases. Dysfunction of the sarco(endo)plasmic reticulum Ca2+-ATPase from fast-twitch skeletal muscle (SERCA1a) is associated with skin and muscle diseases, while mutations of the Cu+-ATPase (CopA) give rise to Cu+ deficiency or excess as seen in the devastating Menkes and Wilson’s diseases. Furthermore, the essential role that these proteins have in all domains of life renders them attractive drug targets in diseases different from those that they are implicated with. For instance, SERCA1a has become an attractive target for inducing apoptosis in proliferating cancer cells while the essential role of CopA in pathogenic bacteria, fungi and parasites makes it an attractive target for novel drugs, battling the near-future threat of antimicrobial resistance. Consequently, unveiling how these two ATPases function at the atomistic level will not only advance basic bioscience, but provide a framework for designing a new generation of drugs against cancer and pathogenic microbes. The goal of this Ph.D. dissertation was to functionally characterize SERCA1a and CopA from Legionella pneumophila (LpCopA) through a range of different methods within structural biology. Crystallographic studies of SERCA1a led to a newly determined crystal structure and helped enlighten how thapsigargin, a potent inhibitor of SERCA1a, depends on a water mediated hydrogen bond network when bound to SERCA1a. Furthermore, molecular dynamics (MD) simulations of the same P-type ATPase were used to assess a long-standing question whether cholesterol affects SERCA1a through direct or indirect interactions. The MD study supported the proposition that cholesterol regulation of SERCA1a is due to an indirect effect. Crystallization of a Wilson’s disease causing mutant inserted into LpCopA, resulted in the determination of a 5 Å resolution structure with a structural fold similar to that of the wild type (WT) protein. The discrepancy between the newly determined crystal structure of LpCopA and the functional manifestations of the missense mutation in human CopA, could indicate that LpCopA is insufficient in structurally elucidating the effect of disease-causing mutations in the human CopA proteins. MD simulations, which combine coarse-grained (CG) and atomistic procedures, were set up in order to elucidate mechanistic implications exerted by the lipid bilayer on LpCopA. The MD simulations of LpCopA corroborated previous and new in vivo activity data and showed that the bacterial, anionic phospholipids, phosphatidylglycerol (PG) and cardiolipin (CL), have an increased propensity to bind to certain areas of the transmembrane domain. Further studies are required to infer whether these observations support specific lipid-protein interactions and what their significance is for LpCopA as a model system as well as the human CopA proteins. A considerable number of crystallization experiments were set up on LpCopA in the pursuit of determining the first metal-bound state of this class of P-type ATPases. Despite various approaches, the results were predominantly discouraging; however, encouraging hits were obtained with AgNO3 and E. coli lipids, potentially underscoring the importance of utilizing native lipids. Finally, atomistic MD simulations of a Zn2+-ATPase (ZntA) were set up and computed in order to elucidate the dynamics of its ion exit pathway, and helped reveal how residues lining the pathway might drive the Zn2+ ion to exit.