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Sample records for nasicon type structure

  1. SPS driven lithium differential diffusion in NASICON-like structures

    Perez-Estebanez, M.; Peiteado, M.; Caballero, A. C.; Palomares, F. J.; Nygren, M.; Isasi Marin, J.

    2016-05-01

    Samples of nominal composition Li{sub 1}.3Fe{sub 0}.3Ti{sub 1}.7(PO{sub 4}){sub 3} with a NASICON-type crystal structure, can be sintered up to 95% of the theoretical density at only 600 degree centigrade using spark plasma sintering, SPS. The final pellets however show different colouration in their upper and lower faces, being the upper face white and the lower one pink. The analysis of both surfaces by XPS shows a higher concentration of lithium on the white upper face, as a consequence of the polar diffusion of ions from the positive to the negative rams during SPS. On the other hand the study by XRD and SEM shows the formation of an extra phase in the upper face with nominal composition LiOPO{sub 4}. A change in the cell parameters of the original NASICON structure is also observed, confirming the diffusion of lithium ions. (Author)

  2. Synthesis of NASICON-type structured NaTi2(PO4)3-graphene nanocomposite as an anode for aqueous rechargeable Na-ion batteries

    Pang, Gang; Yuan, Changzhou; Nie, Ping; Ding, Bing; Zhu, Jiajia; Zhang, Xiaogang

    2014-05-01

    A new solvothermal strategy combined with calcination has been developed to synthesize NaTi2(PO4)3-graphene nanocomposites. X-ray diffraction, thermogravimetric analysis, field-emission scanning electron microscopy and transmission electron microscopy were performed to characterize their microstructures and morphologies. It was found that NASICON-type structured NaTi2(PO4)3 nanoparticles with highly crystallinity were homogeneously anchored on the surface of conducting graphene nanosheets, forming a two-dimensional hybrid nanoarchitecture. A possible growth mechanism was also discussed based on time-dependent experiments. When used as anode materials for Na-ion batteries, the nanocomposites exhibited excellent electrochemical performance with high-rate capability and excellent cycling stability in 1 M Na2SO4 aqueous electrolyte. The electrode delivered high specific capacities of 110, 85, 65, 40 mA h g-1 at 2, 5, 10 and 20 C, respectively, and still retained 90% of the initial capacity after 100 cycles at 2 C.A new solvothermal strategy combined with calcination has been developed to synthesize NaTi2(PO4)3-graphene nanocomposites. X-ray diffraction, thermogravimetric analysis, field-emission scanning electron microscopy and transmission electron microscopy were performed to characterize their microstructures and morphologies. It was found that NASICON-type structured NaTi2(PO4)3 nanoparticles with highly crystallinity were homogeneously anchored on the surface of conducting graphene nanosheets, forming a two-dimensional hybrid nanoarchitecture. A possible growth mechanism was also discussed based on time-dependent experiments. When used as anode materials for Na-ion batteries, the nanocomposites exhibited excellent electrochemical performance with high-rate capability and excellent cycling stability in 1 M Na2SO4 aqueous electrolyte. The electrode delivered high specific capacities of 110, 85, 65, 40 mA h g-1 at 2, 5, 10 and 20 C, respectively, and still retained

  3. Photocatalytic activity of glass ceramics containing Nasicon-type crystals

    Graphical abstract: Display Omitted Highlights: ► Glass ceramics containing Nasicon-type crystals were prepared. ► The glass ceramics showed photocatalytic activity under UV irradiation. ► Higher activity was observed in the MgTi4(PO4)6- and CaTi4(PO4)6-containing glass ceramics. -- Abstract: Glass ceramics were prepared by heat-treating MO–TiO2–P2O5 (M = Mg, Ca, Sr and Ba) and R2O–TiO2–P2O5–SiO2 (R = Li, Na and K) glasses, and their photocatalytic activity was investigated. The crystalline phases precipitated in the glasses were only Nasicon-type crystals, MTi4(PO4)6 or RTi2(PO4)3. Decomposition experiments of both methylene blue (MB) and acetaldehyde showed that the glass ceramics exhibited effective photocatalytic activity. The activity did not depend on the radius of the M2+ or R+ ion, and higher activity was observed in the MgTi4(PO4)6 and CaTi4(PO4)6 precipitated glass ceramics.

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

    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.

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

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

    2014-01-01

    Roč. 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

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

    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.

  7. High lithium-ion conducting NASICON-type Li1+xAlxGeyTi2-x-y(PO4)3 solid electrolyte

    Shang eXuefu; Hiroyoshi eNemori; Shigehi eMitsuoka; Peng eXu; Masaki eMatsui; Yasuo eTakeda; Osamu eYamamoto; Nobuyuki eImanishi

    2016-01-01

    A water-stable solid electrolyte is a key material without which aqueous lithium-air batteries could not be operated. In this study, we have examined the electrical conductivity and mechanical properties of a water-stable lithium ion conducting solid electrolyte, Li1+xAlxGeyTi2-x-y(PO4)3 with the NASICON-type structure, as a function of the Al and Ge content. Li1+xAlxGeyTi2-x-y(PO4)3 was synthesized by the conventional solid-state reaction method. The highest lithium-ion conductivity of 1.0×1...

  8. High lithium-ion conducting NASICON-type Li1+xAlxGeyTi2-x-y(PO43 solid electrolyte

    Shang eXuefu

    2016-04-01

    Full Text Available A water-stable solid electrolyte is a key material without which aqueous lithium-air batteries could not be operated. In this study, we have examined the electrical conductivity and mechanical properties of a water-stable lithium ion conducting solid electrolyte, Li1+xAlxGeyTi2-x-y(PO43 with the NASICON-type structure, as a function of the Al and Ge content. Li1+xAlxGeyTi2-x-y(PO43 was synthesized by the conventional solid-state reaction method. The highest lithium-ion conductivity of 1.0×10-3 S cm-1 at 25 °C and the highest three-point bending strength of 90 N mm-2 at room temperature were observed for a pellet of Li1.45Al0.45Ge0.2Ti1.35(PO43 sintered at 900 °C.

  9. Lithium mobility in the NASICON-type compound LiTi2(PO4)3 by nuclear magnetic resonance and impedance spectroscopies

    Lithium mobility in LiTi2(PO4)3 has been followed by 7Li NMR and impedance spectroscopies. From this analysis, three stages have been distinguished. (1) Below 230 K, lithium occupies preferentially the octahedral M1 sites of the NASICON structure. (2) Between 230 and 330 K, a low correlated and thermally activated lithium motion, with Ea = 0.47 eV, is operating, as deduced from both techniques. (3) Above 330 K, the activation energy decreases and a more extended lithium ionic motion is established. As the lithium mobility increases, progressive occupation of the eight-coordinated M2 sites is deduced from NMR data. (author)

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

    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.

  11. Ion conductivity of nasicon ceramics

    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 β double-prime-alumina ceramics. It is well known that the ion conductivity of β-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

  12. NASICON-Structured NaTi2(PO4)3@C Nanocomposite as the Low Operation-Voltage Anode Material for High-Performance Sodium-Ion Batteries.

    Wang, Dongxue; Liu, Qiang; Chen, Chaoji; Li, Malin; Meng, Xing; Bie, Xiaofei; Wei, Yingjin; Huang, Yunhui; Du, Fei; Wang, Chunzhong; Chen, Gang

    2016-01-27

    NASICON-type structured NaTi2(PO4)3 (NTP) has attracted wide attention as a promising anode material for sodium-ion batteries (SIBs), whereas it still suffer from poor rate capability and cycle stability due to the low electronic conductivity. Herein, the architecture, NTP nanoparticles embedded in the mesoporous carbon matrix, is designed and realized by a facile sol-gel method. Different than the commonly employed potentials of 1.5-3.0 V, the Na(+) storage performance is examined at low operation voltages between 0.01 and 3.0 V. The electrode demonstrates an improved capacity of 208 mAh g(-1), one of the highest capacities in the state-of-the-art titanium-based anode materials. Besides the high working plateau at 2.1 V, another one is observed at approximately 0.4 V for the first time due to further reduction of Ti(3+) to Ti(2+). Remarkably, the anode exhibits superior rate capability, whose capacity and corresponding capacity retention reach 56 mAh g(-1) and 68%, respectively, over 10000 cycles under the high current density of 20 C rate (4 A g(-1)). Worthy of note is that the electrode shows negligible capacity loss as the current densities increase from 50 to 100 C, which enables NTP@C nanocomposite as the prospective anode of SIBs with ultrahigh power density. PMID:26720111

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

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

  14. Li mobility in Nasicon-type materials LiM2(PO4)3, M = Ge, Ti, Sn, Zr and Hf, followed by 7Li NMR spectroscopy.

    Arbi, K; París, M A; Sanz, J

    2011-10-21

    Lithium mobility in LiM(2)(PO(4))(3) compounds, M = Ge and Sn, has been investigated by (7)Li Nuclear Magnetic Resonance (NMR) spectroscopy, and deduced information compared with that reported previously in Ti, Zr and Hf members of the series in the temperature range 100-500 K. From the analysis of (7)Li NMR quadrupole interactions (C(Q) and η parameters), spin-spin T(2)(-1) and spin-lattice T(1)(-1) relaxation rates, structural sites occupancy and mobility of lithium have been deduced. Below 250 K, Li ions are preferentially located at M(1) sites in rhombohedral phases, but occupy intermediate M(12) sites between M(1) and M(2) sites in triclinic ones. In high-temperature rhombohedral phases, a superionic state is achieved when residence times at M(1) and M(12) sites become similar and correlation effects on Li motion decrease. This state can be obtained by large order-disorder transformations in rhombohedral phases or by sharp first order transitions in triclinic ones. The presence of two relaxation mechanisms in T(1)(-1) plots of rhombohedral phases has been associated with departures of conductivity from the Arrhenius behavior. Long term mobility of lithium is discussed in terms of the cation vacancy distribution along conduction paths. PMID:21897945

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

    Nikolay S. Slobodyanik

    2012-07-01

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

  16. Phase Stability and Ionic Conductivity of NASICON-Like Phases in ScPO4-Na3PO4-Li3PO4 Ternary System

    2006-01-01

    Phase formation in ternary system of complex Sc, Na and Li phosphates was studied at 950 ℃ and synthesis of new phases of definite composition was carried out. Obtained specimens were investigated with X-ray powder diffraction, infrared and impedance spectroscopy. Compositions of fields of homogeneity with NASICON-like structure were discovered. Temperature dependency of ionic conductivity was measured.

  17. Highly conducting divalent Mg2+ cation solid electrolytes with well-ordered three-dimensional network structure

    Tamura, Shinji; Yamane, Megumi; Hoshino, Yasunori; Imanaka, Nobuhito

    2016-03-01

    A three-dimensionally well-ordered NASICON-type Mg2+ cation conductor, (MgxHf1-x)4/(4-2x)Nb(PO4)3, was firstly developed by partial substitution of lower valent Mg2+ cation onto the Hf4+ sites in a HfNb(PO4)3 solid to realize high Mg2+ cation conductivity even at moderate temperatures. Due to the formation of well-ordered NASICON-type structure, both the high Mg2+ cation conductivity below 450 °C and the low activation energy for Mg2+ cation migration was successfully realized for the (Mg0.1Hf0.9)4/3.8Nb(PO4)3 solid. Pure Mg2+ cation conduction in the NASICON-type (Mg0.1Hf0.9)4/3.8Nb(PO4)3 solid was directly and quantitatively demonstrated by means of two kinds of dc electrolysis.

  18. Improving NASICON Sinterability through Crystallization under High Frequency Electrical Fields

    Ilya eLisenker

    2016-03-01

    Full Text Available The effect of high frequency (HF electric fields on the crystallization and sintering rates of a lithium aluminum germanium phosphate (LAGP ion conducting ceramic was investigated. LAGP with the nominal composition Li1.5Al0.5Ge1.5(PO43 was crystallized and sintered, both conventionally and under effect of electrical field. Electrical field application, of 300V/cm at 1MHz, produced up to a 40% improvement in sintering rate of LAGP that was crystallized and sintered under the HF field. Heat sink effect of the electrodes appears to arrest thermal runaway and subsequent flash behavior. Sintered pellets were characterized using XRD, SEM, TEM and EIS to compare conventionally and field sintered processes. The as-sintered structure appears largely unaffected by the field as the sintering curves tend to converge beyond initial stages of sintering. Differences in densities and microstructure after 1 hour of sintering were minor with measured sintering strains of 31% vs. 26% with and without field, respectively . Ionic conductivity of the sintered pellets was evaluated and no deterioration due to the use of HF field was noted, though capacitance of grain boundaries due to secondary phases was significantly increased.

  19. Caustic Recycle from Hanford Tank Waste Using NaSICON Ceramic Membrane Salt Splitting Process

    Fountain, Matthew S.; Kurath, Dean E.; Sevigny, Gary J.; Poloski, Adam P.; Pendleton, J.; Balagopal, S.; Quist, M.; Clay, D.

    2009-02-20

    A family of inorganic ceramic materials, called sodium (Na) Super Ion Conductors (NaSICON), has been studied at Pacific Northwest National Laboratory (PNNL) to investigate their ability to separate sodium from radioactively contaminated sodium salt solutions for treating U.S. Department of Energy (DOE) tank wastes. Ceramatec Inc. developed and fabricated a membrane containing a proprietary NAS-GY material formulation that was electrochemically tested in a bench-scale apparatus with both a simulant and a radioactive tank-waste solution to determine the membrane performance when removing sodium from DOE tank wastes. Implementing this sodium separation process can result in significant cost savings by reducing the disposal volume of low-activity wastes and by producing a NaOH feedstock product for recycle into waste treatment processes such as sludge leaching, regenerating ion exchange resins, inhibiting corrosion in carbon-steel tanks, or retrieving tank wastes.

  20. Abstract Machine for Typed Feature Structures

    Wintner, Shuly; Francez, Nissim

    1995-01-01

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

  1. Extraordinary electronic properties in uncommon structure types

    Ali, Mazhar Nawaz

    In this thesis I present the results of explorations into several uncommon structure types. In Chapter 1 I go through the underlying idea of how we search for new compounds with exotic properties in solid state chemistry. The ideas of exploring uncommon structure types, building up from the simple to the complex, using chemical intuition and thinking by analogy are discussed. Also, the history and basic concepts of superconductivity, Dirac semimetals, and magnetoresistance are briefly reviewed. In chapter 2, the 1s-InTaS2 structural family is introduced along with the discovery of a new member of the family, Ag0:79VS2; the synthesis, structure, and physical properties of two different polymorphs of the material are detailed. Also in this chapter, we report the observation of superconductivity in another 1s structure, PbTaSe2. This material is especially interesting due to it being very heavy (resulting in very strong spin orbit coulping (SOC)), layered, and noncentrosymmetric. Electronic structure calculations reveal the presence of a bulk 3D Dirac cone (very similar to graphene) that is gapped by SOC originating from the hexagonal Pb layer. In Chapter 3 we show the re-investigation of the crystal structure of the 3D Dirac semimetal, Cd3As2. It is found to be centrosymmetric, rather than noncentrosymmetric, and as such all bands are spin degenerate and there is a 4-fold degenerate bulk Dirac point at the Fermi level, making Cd3As2 a 3D electronic analog to graphene. Also, for the first time, scanning tunneling microscopy experiments identify a 2x2 surface reconstruction in what we identify as the (112) cleavage plane of single crystals; needle crystals grow with a [110] long axis direction. Lastly, in chapter 4 we report the discovery of "titanic" (sadly dubbed ⪉rge, nonsaturating" by Nature editors and given the acronym XMR) magnetoresistance (MR) in the non-magnetic, noncentrosymmetric, layered transition metal dichalcogenide WTe2; over 13 million% at 0.53 K in

  2. Preparación cristaloquímica y comportamiento eléctrico de electrolitos sólidos de estequiometría NASICON

    Maldonado Manso, María Pilar

    2004-01-01

    En el presente trabajo se ha llevado a cabo la preparación y la caracterización estructural y eléctrica de varias series de materiales de estequiometría NASICON, sistema ampliamente conocido por sus propiedades conductoras y adecuadas prestaciones en el campo de los electrolitos sólidos. Las síntesis se han realizado, en general, en estado sólido por el método cerámico, caracterizándose los compuestos obtenidos empleando muy diversas técnicas como difracción de rayos-X y/o neut...

  3. Interference enhanced thermoelectricity in quinoid type structures

    Strange, M., E-mail: strange@chem.ku.dk; Solomon, G. C. [Nano-Science Center and Department of Chemistry, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen Ø (Denmark); Seldenthuis, J. S.; Verzijl, C. J. O.; Thijssen, J. M. [Kavli Institute of Nanoscience, Delft University of Technology, 2628 CJ Delft (Netherlands)

    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 π-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{sup 2}G and figure of merit ZT, where S is the Seebeck coefficient, making quinoid type molecules potential candidates for efficient thermoelectric devices.

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

    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)

  5. Synthesis, crystal structure and vibrational spectra of Sr0.5Zr2(AsO4)3

    Jrifi, A.; El Jazouli, Abdelaziz; Chaminade, Jean-Pierre; Couzi, Michel

    2009-01-01

    Sr0.5Zr2(AsO4)3 arsenate was prepared and structurally characterized by powder X-ray diffraction and by Raman and infrared spectroscopies. Its structure, which belongs to the Nasicon-type family, was refined by the Rietveld method in the R-3 space group, from X-ray powder diffraction data. The hexagonal unit-cell parameters were determined to be ah=8.965(2)  Å, ch=23.955(6)  Å, V=1667.43(6)  Å3, and Z=6. The structure is formed by an ionic three-dimensional network of AsO4 tetrahedra and ZrO6...

  6. Synthesis of nano structured particles for Li-ion cathodic and anodic materials obtained by spray pyrolysis

    The development of the nano technology has contributed to improve the electrochemical properties in rechargeable batteries. The Spray Pyrolysis method allows to obtain nano structured materials with spherical morphology, narrow particle size distribution and compositional homogeneity. Nano structured particles have been prepared in this work to be used as anodic and cathodic materials in lithium-ion batteries. Among the cathodic materials, the Na-Si-Con (Li3Fe2(PO4)3) structure and the olivine (LiFePO4) phases have been synthesised. The Na-Si-Con iron phosphate favours the accommodation of the ion host, the diffusion and thermal stability. The olivine structure has an open three-dimensional network, favourable for hosting Lithium ions. The characterization by X ray diffraction, electron microscopy (scanning and transmission) and electron diffraction have allowed to identify a mix of crystalline phases of LiFePO4 (Olivine) and Li3Fe2(PO4)3 (Na-Si-Con). Thermal treatments produce porous particles. The tryphilite phase (olivine) appears after a thermal treatment at 800 degree centigrade/12h. Electrochemical results confirm the presence of the Na-Si-Con and olivine phases. Among the materials for being used as anode, the titanium oxides have been classified as good candidates as lithium ion host. The synthesis results in different experimental conditions for obtaining spherical and nano structured titanium oxide particles are presented. (Author)

  7. Parameterized type expansion in the feature structure formalism TDL

    Schäfer, Ulrich

    1995-01-01

    Over the last few years, unification-based grammar formalisms have become the predominant paradigm in natural language processing systems because of their monotonicity, declarativeness, and reversibility. From the viewpoint of computer science, typed feature structures can be seen as data structures that allow representation of linguistic knowledge in a uniform fashion. Type expansion is an operation that makes the constraints on a typed feature structure explicit and determines their satisfi...

  8. New structure type of Lu5Ni19B6

    The powder method was used to investigate Lu5-Ni19B6 structure belonging to a new type: sp. g. P6/mmm, a=0.4943(1), c=1.7161(9) nm, N=30 (R=0.120). The L45Ni19B6 structure is a new representative of the homologous series based on CaCu5 and CeCo3B2 types; its elementary cell contains two layers of CaCu5 type structure and three layers of CeCo3B2 type structure. Structure of the new L45Ni19B6 type belongs to the class of structures with trigonal-prismatic coordination of smallest atoms

  9. Types and Functions of Coastal Structures

    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...

  10. Hodge-type structures as link invariants

    Borodzik, Maciej; Nemethi, Andras

    2010-01-01

    Based on some analogies with the Hodge theory of isolated hypersurface singularities, we define Hodge-type numerical invariants (called H-numbers) of any, not necessarily algebraic, link in $S^3$. They contain the same information as the (normalized) real Seifert matrix. We study their basic properties, we express the Tristram-Levine signatures and the higher order Alexander polynomial in terms of them. Motivated by singularity theory, we also introduce the spectrum of the link (determined fr...

  11. Structure sensitive properties of KTP-type crystals

    2001-01-01

    Adding various dopants during the growth of the parent KTiOPO4 (KTP) crystal has given rise to an extensive series of KTP-type crystals. The doped KTP or KTP-type crystals often have very subtle structural variations from pure KTP crystals. As a result of these structural changes the KTP-type crystals often exhibit different physical properties, which may be referred to as structure sensitive properties. It is possible to fine-tune the nonlinear optical properties of KTP crystals through doping. This results in a broad range of applications for KTP-type crystals.

  12. Comments on structural types of toroidal carbon nanotubes

    Chuang, Chern; Jin, Bih-Yaw

    2012-01-01

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

  13. Bloch-Floquet type waves in periodic ferromagnetic layered structure

    Danoyan Z.N.

    2014-06-01

    Full Text Available The Bloch-Floquet type waves existence and propagation in ferromagnetic periodic layered structure are investigated. The dispersion equation obtained and investigated. It is shown that the waves spectrum contains forbidden zones.

  14. Types of Structural Unemployment in the United Kingdom.

    Hart, Peter E.

    1990-01-01

    Assesses the extent of the following types of structural unemployment in the United Kingdom: technological change, skills mismatch, geographical mismatch, demographic shifts, institutional rigidity, unemployability, and capital restructuring. Concludes that measurement is difficult and the types create segmented labor markets that obstruct the…

  15. PROVIDING SERVICEABILITY OF STRUCTURAL BEARING TYPES FOR ROADWAY BRIDGES

    R. I. Polyuga

    2010-03-01

    Full Text Available In the article the description of structural bearing types for roadway bridges and their classification is given. Special attention is paid to effective bearings with elastomeric materials – rubber, pot, spherical ones. Characteristic defects of structural bearings and demands of serviceability are noticed.

  16. Stochastic Fatigue Analysis of Jacket Type Offshore Structures

    Sigurdsson, Gudfinnur

    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...

  17. Structures of the lovozerite type - a quantitative investigation

    The structure of lovozerite is derived from perovskite. For 24 members of the lovozerite family an aristotype is postulated. The method of quantitative comparison using the concept of mappings is applied to the lovozerite family using the aristotype as a 'structural unit'. The method is extended to relationships of symmetry-type II, i.e. the derived structure and the aristotype have only a common subgroup, the remaining non-common symmetry of the derived structure is used as 'distribution' symmetry for the structural unit. The numerical results are discussed in detail. (orig.)

  18. Structural determination of wild-type lactose permease

    Guan, Lan; Mirza, Osman; Verner, Gillian; Iwata, So; Kaback, H. Ronald

    2007-01-01

    Here we describe an x-ray structure of wild-type lactose permease (LacY) from Escherichia coli determined by manipulating phospholipid content during crystallization. The structure exhibits the same global fold as the previous x-ray structures of a mutant that binds sugar but cannot catalyze translocation across the membrane. LacY is organized into two six-helix bundles with twofold pseudosymmetry separated by a large interior hydrophilic cavity open only to the cytoplasmic side and containin...

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

    Golestan, Saeed; Fernandez, Francisco Daniel Freijedo; Vidal, Ana;

    2014-01-01

    -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......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...

  20. A genetic and computational approach to structurally classify neuronal types

    Sümbül, Uygar; Song, Sen; McCulloch, Kyle; Becker, Michael; Lin, Bin; Sanes, Joshua R.; Masland, Richard H.; Seung, H. Sebastian

    2014-01-01

    The importance of cell types in understanding brain function is widely appreciated but only a tiny fraction of neuronal diversity has been catalogued. Here, we exploit recent progress in genetic definition of cell types in an objective structural approach to neuronal classification. The approach is based on highly accurate quantification of dendritic arbor position relative to neurites of other cells. We test the method on a population of 363 mouse retinal ganglion cells. For each cell, we de...

  1. Structural-communicative types of the perplexed echo question

    VOROBYOVA ELENA N.

    2015-01-01

    Modern linguistics has shown us that the language is not limited to questions with the standard semantics of interrogation. Among the interrogative sentences used in the secondary functions one can find inquiries with additional emotional colourings. Perplexity is the closest emotional evaluative meaning, accompanying the interrogative semantics of a question. In the paper, one of the structural-communicative types of the perplexed question (an echo question) is considered. Two structural typ...

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

    Cohen, O.; Drake, J. J.; 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...

  3. Structure Stability of Ⅰ-Type Carbon Nanotube Junctions

    夏丹; 袁喆; 李家明

    2002-01-01

    Carbon nanotubes with junctions may play an important role in future ‘nanoelectronics' and future ‘nano devices'.In particular, junctions constructed with metal and semiconducting nanotubes have potential applications. Basedon the orthogonal tight-binding molecular dynamics method, we present our study of the structure stability ofI-type carbon nanotube junctions.

  4. Crystal structure of clathrates of Hofmann dma-type

    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

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

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

  6. The Gd14Ag51 structure type and its relation to some complex amalgam structures

    Highlights: • The Gd14Ag51 structure type has been revisited on the basis of single crystal diffraction data. • Symmetry analysis from electron density and TEM shows the space group P6/m to be true. • Gd14Ag51 shows good metallic behaviour. • Structure relations to alkali, alkaline-earth and rare-earth metal amalgams can be established. • Complexity values for the RE14Ag51 structure family were calculated. - Abstract: A plethora of binary and ternary intermetallic compounds has been assigned to the Gd14Ag51 structure type, crystallising in the hexagonal system (space group P6/m, a = 1264.30(18) pm, c = 933.58(11) pm for Gd14Ag51). Starting in the late 1960s, much work has been invested in the structural elucidation of these crystal structures. However, reliable single crystal data are scarce, and most structure type assignments have been performed merely on the basis of powder data. We have redetermined four representatives of the binary RE14Ag51 structure type (RE = Y, Ce, Gd, Tb) with modern high-precision single crystal X-ray methods. The assignment of the Gd14Ag51 structure type to space group P6/m was additionally verified by careful analysis of high resolution transmission electron micrographs. We emphasise the close relation of the Gd14Ag51 structure type to the structures of some recently described amalgams of similar composition focussing on disorder phenomena and structural complexity. Furthermore, we provide detailed information on synthesis as well as electrical and magnetic properties for Gd14Ag51, the parent compound of this structure family

  7. Atomic structures of icosahedral phases of type F and dislocations

    The object of this thesis is the study of atomic structures of icosahedral phases of type F and their dislocations. In this study, we have first built a prototypical structure that describes the already known F type icosahedral phases. In order to check it we synthesized some of the new compositions predicted by this model. This synthesis led to the discovery of two new quasi-periodical phases of the stoichiometry Al66,08Cu21,35Mn8,29Fe4,28. One of these phases is icosahedral (metastable) of type F and the other one is decagonal (stable). A F-IQC phase is present on these compounds that have a different composition with respect to the ones already studied for the system (Al,Pd,Fe). Globally, these experimental results on new icosahedral phases allowed to prove the viability of the model: on the three samples of new composition, two of them have shown the existence of icosahedral phases of type F and the third one has given a decagonal phase, in relation of canonical orientation with the icosahedral metastable phase (10-fold axis parallel with 5-fold axis). Using this reliable model, we have been able to introduce dislocations. We could thus provide the geometry of dislocations (outside the dislocation core) at atomic scale for F-IQC phases. On this structure we have also identified the distributions of phasons and given some elements of answer for the global dislocations moves. (author)

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

    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

  9. NEW TYPE OF VIBRATION STRUCTURE OF VERTICAL DYNAMIC BALANCING MACHINE

    Li Dinggen; Cao Jiguang; Chen Chuanyao; Wang Junwen

    2004-01-01

    A new type of vibration structure of vertical dynamic balancing machine is designed, which is based on the analysis for swing frame of a traditional vertical dynamic balancing machine. The static unbalance and couple unbalance can be separated effectively by using the new machine with the new swing frame. By building the dynamics model, the advantages of the new structure are discussed in detail. The modal and harmonic response are analyzed by using the ANSYS7.0. By comparing the finite element modal analysis with the experimental modal analysis, the natural frequencies and vibration modes are found out. There are many spring boards in the new swing frame. Their stiffness is different and assort with each other. Furthermore, there are three sensors on the measurement points. Therefore, the new dynamic balancing machine can measure the static unbalance and couple unbalance directly, and the influence between them is faint. The new structure has the function of belt-strain compensation to improve the measurement precision. The practical result indicates that the new vertical dynamic balancing machine is suitable for inertial measurement of flying objects, and can overcome the shortcomings of traditional double-plane vertical dynamic balancing machines. The vertical dynamic balancing machine with the new vibration structure can be widely used in the future applications. The modeling and analysis of the new vibration structure provide theoretic instruction and practical experience for designing new type of vertical dynamic balancing machines. Based on the design principles such as stiffness-matching, frequency-adjacence and strain-compensation and so on, various new type of vibration structures can be designed.

  10. Effects of structure type on viscoelastic properties of geosynthetics

    I.I. Loginova

    2015-06-01

    Full Text Available This work presents a study on tensile properties of geosynthetic materials. There were investigated six samples of geofabrics and geogrids with different structures including woven geotextile fabrics, nonwoven geotextile fabrics, warp-knitted geogrids and extruded geogrid. The study determined tensile properties of geosynthetics including tensile strength, strain at the maximum load and tensile load at a specified strain. The authors carried out creep and relaxation tests. It was found that the structure type significantly affects viscoelastic properties of geosynthetics materials. The article presents some results of numerous tests, which may be used to pre-select geosynthetics materials.

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

    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.

  12. New compounds with YCrB4-type structure

    This paper investigates part of the Yb- Fe, Co, Ni -B ternary systems to obtain borides with YCrB4-type structure. Compact Yb of 99.94 mass % purity and precompacted powders of finely crystalline boron, Fe, Co, or Ni were fused in an electric-arc furnace in an atmosphere of purified argon. The results of x-ray phase-shift analysis showed that borides with YCrB4-type structure were formed in 11 of the studied systems. The obtained values of the unit-cell parameters for the compounds YbCoB4, YbFeB4, and YbNiB4 are inscribed smoothly in the curve of the change of unit-cell parameters and volumes of RMB4 compounds, which indicates a trivalent state of the ytterbium atoms in these borides

  13. Seismic vulnerability of historical arch type bridge structures in Italy

    Qadir Bhatti, Abdul

    2009-01-01

    Italy is located on a earthquake prone area and old bridges were desinged without any seismic provision. In the years (2009), tremors were felt in Italy due to the strong earthquakes at Abruzzo, which highlight the earthquake threat to Italy. This study focuses on seismic vulnerability of arch type masonry bridge structures in Italy, designed primarily for gravity loads, when they are subjected to earthquakes. A case study has been carried out for the vulnerability study for a ...

  14. Numerical Simulation of Pool Boiling from Reentrant Type Structured Surfaces

    Dietl, Jochen

    2015-01-01

    Enhancement of heat transfer in pool boiling can be achieved by employing a structured surface. So called reentrant type surfaces, consisting of subsurface tunnels connected through pores with the pool, were found to strongly improve the performance of heat exchanger tubes. Although employed since decades, several of the processes within the tunnel are not understood and the presented models are not able to predict the different boiling modes. With the rapid development of numerical method...

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

    Guo, J.; Erskine, P. T.; Coker, A. R.; Wood, S. P.; Cooper, J. B.; Mareš, Michael; Baudyš, Miroslav

    2015-01-01

    Roč. 192, č. 3 (2015), s. 554-560. ISSN 1047-8477 R&D Projects: GA ČR GA15-18929S; GA MŠk LO1302 Institutional support: RVO:61388963 Keywords : potato cathepsin D inhibitor * Kunitz-type protease inhibitor * protein X-ray structure * reactive-site loop * docking Subject RIV: CE - Biochemistry Impact factor: 3.231, year: 2014

  16. Babel Fortran 2003 Binding for Structured Data Types

    Muszala, S; Epperly, T; Wang, N

    2008-05-02

    Babel is a tool aimed at the high-performance computing community that addresses the need for mixing programming languages (Java, Python, C, C++, Fortran 90, FORTRAN 77) in order to leverage the specific benefits of those languages. Scientific codes often rely on structured data types (structs, derived data types) to encapsulate data, and Babel has been lacking in this type of support until recently. We present a new language binding that focuses on their interoperability of C/C++ with Fortran 2003. The new binding builds on the existing Fortran 90 infrastructure by using the iso-c-binding module defined in the Fortran 2003 standard as the basis for C/C++ interoperability. We present the technical approach for the new binding and discuss our initial experiences in applying the binding in FACETS (Framework Application for Core-Edge Transport Simulations) to integrate C++ with legacy Fortran codes.

  17. Population structure and minimum core genome typing of Legionella pneumophila.

    Qin, Tian; Zhang, Wen; Liu, Wenbin; Zhou, Haijian; Ren, Hongyu; Shao, Zhujun; Lan, Ruiting; Xu, Jianguo

    2016-01-01

    Legionella pneumophila is an important human pathogen causing Legionnaires' disease. In this study, whole genome sequencing (WGS) was used to study the characteristics and population structure of L. pneumophila strains. We sequenced and compared 53 isolates of L. pneumophila covering different serogroups and sequence-based typing (SBT) types (STs). We found that 1,896 single-copy orthologous genes were shared by all isolates and were defined as the minimum core genome (MCG) of L. pneumophila. A total of 323,224 single-nucleotide polymorphisms (SNPs) were identified among the 53 strains. After excluding 314,059 SNPs which were likely to be results of recombination, the remaining 9,165 SNPs were referred to as MCG SNPs. Population Structure analysis based on MCG divided the 53 L. pneumophila into nine MCG groups. The within-group distances were much smaller than the between-group distances, indicating considerable divergence between MCG groups. MCG groups were also supplied by phylogenetic analysis and may be considered as robust taxonomic units within L. pneumophila. Among the nine MCG groups, eight showed high intracellular growth ability while one showed low intracellular growth ability. Furthermore, MCG typing also showed high resolution in subtyping ST1 strains. The results obtained in this study provided significant insights into the evolution, population structure and pathogenicity of L. pneumophila. PMID:26888563

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

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

    2012-08-31

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

  19. The Structure of Workaholism and Types of Workaholic

    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.

  20. Structural analysis of a new type lightweight optical mirror blank

    Li, Yeping; Cui, Xiangqun; Hu, Ningsheng

    2010-07-01

    To reduce the cost and increase the feasibility of the astronomical optical telescope, modern large optical telescope is normally required to be as light as possible. Therefore lightweight mirror is always pursued by large telescopes development. In this paper, a new type lightweight optical mirror blank, the evaluation of its technical feasibility and the reduction of cost are introduced. For the purpose of applying active optics with this lightweight mirror blank, the structural analysis, thermal analysis and optical performance simulation by the finite element method have been presented.

  1. Narrowband frequency-drift structures in solar type IV bursts

    Nishimura, Yukio; Ono, Takayuki; Tsuchiya, Fuminori; Misawa, Hiroaki; Kumamoto, Atsushi; Katoh, Yuto; Masuda, Satoshi; Miyoshi, Yoshizumi

    2013-12-01

    We have established the Zao Solar Radiospectrograph (ZSR), a new solar radio observation system, at the Zao observatory of Tohoku University, Japan. We observed narrowband fine structures with type IV bursts with ZSR on 2 and 3 November 2008. The observed fine structures are similar to fiber bursts in terms of the drift rates and the existence of emission and absorption stripes. Statistical analysis of the drift rates, however, shows that the observed fine structures are different from the ordinary fiber bursts as regards the sense and the magnitude of their drift rates. First, the observed drift rates include both positive and negative rates, whereas ordinary fiber bursts are usually characterized by negative drift rates. Second, the absolute values of the observed drift rates are tens of MHz s-1, whereas the typical drift rate of fiber bursts at 325 MHz is approximately -9 MHz s-1. In addition, all fine structures analyzed have narrow emission bands of less than 17 MHz. We also show that the observed narrowband emission features with drift rates of approximately 40 MHz s-1 can be interpreted as the propagation of whistler-mode waves, which is the same process as that underlying fiber bursts.

  2. Structure and organization of heteromeric AMPA-type glutamate receptors.

    Herguedas, Beatriz; García-Nafría, Javier; Cais, Ondrej; Fernández-Leiro, Rafael; Krieger, James; Ho, Hinze; Greger, Ingo H

    2016-04-29

    AMPA-type glutamate receptors (AMPARs), which are central mediators of rapid neurotransmission and synaptic plasticity, predominantly exist as heteromers of the subunits GluA1 to GluA4. Here we report the first AMPAR heteromer structures, which deviate substantially from existing GluA2 homomer structures. Crystal structures of the GluA2/3 and GluA2/4 N-terminal domains reveal a novel compact conformation with an alternating arrangement of the four subunits around a central axis. This organization is confirmed by cysteine cross-linking in full-length receptors, and it permitted us to determine the structure of an intact GluA2/3 receptor by cryogenic electron microscopy. Two models in the ligand-free state, at resolutions of 8.25 and 10.3 angstroms, exhibit substantial vertical compression and close associations between domain layers, reminiscent of N-methyl-D-aspartate receptors. Model 1 resembles a resting state and model 2 a desensitized state, thus providing snapshots of gating transitions in the nominal absence of ligand. Our data reveal organizational features of heteromeric AMPARs and provide a framework to decipher AMPAR architecture and signaling. PMID:26966189

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

    Kretke, Katherine A

    2012-01-01

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

  4. Bismuth zinc vanadate, BiZn2VO6: New crystal structure type and electronic structure

    We report a combined experimental and computational study of the crystal structure and electronic properties of bismuth zinc vanadate, BiZn2VO6, known for its visible light photocatalytic activity. The crystal structure has been solved from laboratory powder X-ray diffraction data using the repeated minimisations from random starting values method. BiZn2VO6 adopts a new structure type, based on the following building blocks: corner- and edge-sharing ZnO4 tetrahedra, ZnO6 octahedra and VO4 tetrahedra, and Bi2O12 dimers. It is the only known member of the BiM2AO6 (M=Pb, Ca, Cd, Mn, Zn, Mg, Cu; A=V, P, As) family which does not appear to be structurally closely related to others. The electronic structure of BiZn2VO6, calculated by DFT methods, shows that it is an indirect gap semiconductor with a calculated band gap of 1.6 eV, which compares favourably to the experimentally measured value of 2.4 eV. - Graphical abstract: The crystal structure of BiZn2VO6, a new structure type in the BiM2AO6 (M=Mg, Ca, Cd, Cu, Pb, Mn, Zn; A=V, P, As) family. - Highlights: • Structure solution from PXRD data by repeated minimisations from random starting values. • New structure type in the BiM2AO6 (M=Pb, Ca, Cd, Mn, Zn, Mg, Cu; A=V, P, As) family. • Electronic structure calculation

  5. Structural trends in off stoichiometric chalcopyrite type compound semiconductors

    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

  6. Structural Characterization of Novel Pseudomonas aeruginosa Type IV Pilins

    Nguyen, Y.; Jackson, S; Aidoo, F; Junop, M; Burrows, L

    2010-01-01

    Pseudomonas aeruginosa type IV pili, composed of PilA subunits, are used for attachment and twitching motility on surfaces. P. aeruginosa strains express one of five phylogenetically distinct PilA proteins, four of which are associated with accessory proteins that are involved either in pilin posttranslational modification or in modulation of pilus retraction dynamics. Full understanding of pilin diversity is crucial for the development of a broadly protective pilus-based vaccine. Here, we report the 1.6-{angstrom} X-ray crystal structure of an N-terminally truncated form of the novel PilA from strain Pa110594 (group V), which represents the first non-group II pilin structure solved. Although it maintains the typical T4a pilin fold, with a long N-terminal {alpha}-helix and four-stranded antiparallel {beta}-sheet connected to the C-terminus by a disulfide-bonded loop, the presence of an extra helix in the {alpha}{beta}-loop and a disulfide-bonded loop with helical character gives the structure T4b pilin characteristics. Despite the presence of T4b features, the structure of PilA from strain Pa110594 is most similar to the Neisseria gonorrhoeae pilin and is also predicted to assemble into a fiber similar to the GC pilus, based on our comparative pilus modeling. Interactions between surface-exposed areas of the pilin are suggested to contribute to pilus fiber stability. The non-synonymous sequence changes between group III and V pilins are clustered in the same surface-exposed areas, possibly having an effect on accessory protein interactions. However, based on our high-confidence model of group III PilA{sub PA14}, compensatory changes allow for maintenance of a similar shape.

  7. Gradient type optimization methods for electronic structure calculations

    Zhang, Xin; Wen, Zaiwen; Zhou, Aihui

    2013-01-01

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

  8. Electronic structure of p type Delta doped systems

    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)

  9. Structure of the atmosphere of late-type stars

    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

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

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

    1988-01-01

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

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

    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.)

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

    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...

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

    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.)

  14. Galaxy clusters, type Ia supernovae and the fine structure constant

    Holanda, R F L; Colaço, L R; Alcaniz, J S; Landau, S J

    2016-01-01

    As is well known, measurements of the Sunyaev-Zeldovich effect can be combined with observations of the X-ray surface brightness of galaxy clusters to estimate the angular diameter distance to these structures. In this paper, we show that this technique depends on the fine structure constant, $\\alpha$. Therefore, if $\\alpha$ is a time-dependent quantity, e.g., $\\alpha=\\alpha_0 \\phi(z)$, where $\\phi$ is a function of redshift, we argue that current data do not provide the real angular diameter distance, $D_{\\rm{A}}(z)$, to the cluster but instead $D_A^{data}(z) = \\phi(z)^2 D_{\\rm{A}}(z)$. We use this result to derive constraints on a possible variation of $\\alpha$ for a class of dilaton runaway models considering a sample of 25 measurements of $D_A^{data}(z)$ in redshift range $0.023 < z < 0.784$ and estimates of $D_{\\rm{A}}(z)$ from current type Ia supernovae observations. We find no significant indication of variation of $\\alpha$ with the present data.

  15. Structural controls of shihongtan sandstone-type uranium deposit in the southwestern turpan-hami basin

    Through studying the structural evolution, structural characteristics of Shihongtan sandstone-type uranium deposit, it is found that there are three types of structural controls on Shihongtan sandstone-type uranium deposit on the Aiding structural slope, namely, the uranium sources, types of the sedimentary formation of target horizons and the mineralization epochs are controlled by the structural evolution of the basin; the mineralization area are controlled by the structural slope units; the distribution of uranium ore bodies is controlled by the second order structures on the structural slope. (authors)

  16. Structural health monitoring of PC structures with novel types of distributed sensors

    Yang, Caiqian; Wu, Zhishen; Zhang, Yufeng

    2010-04-01

    In this paper, the structural health monitoring of a pre-stressed concrete (PC) structure based on two types of distributed sensing techniques is addressed. The sensing elements are Brillouin scattering-based fiber optic sensors (FOSs) and HCFRP (hybrid carbon fiber reinforced polymer) sensors composed of three types of carbon tows. Both types of sensors are characterized by a broad-based and distributed sensing function. The HCFRP sensors are bonded on PC tendon, steel reinforcing bar, and embedded in tensile and compressive concrete sides with epoxy resins and putties. The FOSs are embedded in the tensile and compressive concrete sides where the HCFRP sensors are embedded as well. The distributed sensors are arranged to detect and monitor the initiation and propagation of cracks, yielding of steel reinforcements and corrosion of PC tendons. The experimental investigations demonstrate that the initiation and location of cracks, yielding of steel reinforcements, corrosion of PC tendons and structural health of PC structures can be effectively detected and monitored with such kinds of distributed sensing systems.

  17. Structural trends in off stoichiometric chalcopyrite type compound semiconductors

    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

  18. Synthetic collagen heterotrimers: structural mimics of wild-type and mutant collagen type I.

    Gauba, Varun; Hartgerink, Jeffrey D

    2008-06-11

    Collagen type I is an AAB heterotrimer assembled from two alpha1 chains and one alpha2 chain. Missense mutations in either of these chains that substitute a glycine residue in the ubiquitous X-Y-Gly repeat with a bulky amino acid leads to osteogenesis imperfecta (OI) of varying severity. These mutations have been studied in the past using collagen-like peptide homotrimers as a model system. However, homotrimers, which by definition will contain glycine mutations in all the three chains, do not accurately mimic the mutations in their native form and result in an exaggerated effect on stability and folding. In this article, we report the design of a novel model system based upon collagen-like heterotrimers that can mimic the glycine mutations present in either the alpha1 or alpha2 chains of type I collagen. This design utilizes an electrostatic recognition motif in three chains that can force the interaction of any three peptides, including AAA (all same), AAB (two same and one different), or ABC (all different) triple helices. Therefore, the component peptides can be designed in such a way that glycine mutations are present in zero, one, two, or all three chains of the triple helix. With this design, we for the first time report collagen mutants containing one or two glycine substitutions with structures relevant to native forms of OI. Furthermore, we demonstrate the difference in thermal stability and refolding half-life times between triple helices that vary only in the frequency of glycine mutations at a particular position. PMID:18481852

  19. Observations of the structure of Type IIIb radio bursts

    The authors have observed short duration, narrow band Type IIIb radio bursts that occur just before the onset of a normal Type III burst. These observations were made with a multichannel radiometer with a center frequency of 25 MHz, time constant of 10 milliseconds and frequency resolution of 100 KHz. The average half power duration of a typical element of a Type III burst was determined. It was found to be very similar to the time profile of a normal Type III burst, i.e., sharp rise and exponential type decay. (Auth.)

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

    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

  1. 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

    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)

  2. Well-formedness and typing rules for UML Composite Structures

    Dragomir, Iulia; Ober, Iulian

    2010-01-01

    Starting from version 2.0, UML introduced hierarchical composite structures, which are an expressive way of defining complex software architectures, but which have a very loosely defined semantics in the standard. In this paper we propose a set of consistency rules that disambiguate the meaning of UML composite structures. Our primary goal was to have an operational model of composite structures for the OMEGA UML profile, an executable profile dedicated to the formal specification and validat...

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

    TETIANA PARTYKO

    2013-01-01

    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 mot...

  4. New insights into structure and function of type I collagen

    Xiong, Xin

    2008-01-01

    Collagen is one of the most abundant proteins in mammalians and strongly conserved throughout evolution. It constitutes one third of the human proteome and comprises three-quarters of the dry weight of human skin. It is widely accepted as a major structural component in animal body such as in bones, cartilage and skins. More and more studies have shown that, in addition to the structural function, collagens can induce or regulate many cellular functions and processes such as cell differentiat...

  5. Soil/structure interactions of eastern US type earthquakes

    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

  6. Structural and evolutionary relationships of "AT-less" type I polyketide synthase ketosynthases

    Lohman, Jeremy; Ma, Ming; Osipiuk, Jerzy; Nocek, Boguslaw; Kim, Youngchang; Chang, Changsoo; Cuff, Marianne E.; Mack, Jamey; Bigelow, Lance; Li, Hui; Endres, Michael; Babnigg, Gyorgy; Joachimiak, Andrzej; Phillips, George N.; Shen, B G

    2015-10-13

    Acyltransferase (AT)-less type I polyketide synthases (PKSs) break the type I PKS paradigm. They lack the integrated AT domains within their modules and instead use a discrete AT that acts in trans, whereas a type I PKS module minimally contains AT, acyl carrier protein (ACP), and ketosynthase (KS) domains. Structures of canonical type I PKS KS-AT didomains reveal structured linkers that connect the two domains. AT-less type I PKS KSs have remnants of these linkers, which have been hypothesized to be AT docking domains. Natural products produced by AT-less type I PKSs are very complex because of an increased representation of unique modifying domains. AT-less type I PKS KSs possess substrate specificity and fall into phylogenetic clades that correlate with their substrates, whereas canonical type I PKS KSs are monophyletic. We have solved crystal structures of seven AT-less type I PKS KS domains that represent various sequence clusters, revealing insight into the large structural and subtle amino acid residue differences that lead to unique active site topologies and substrate specificities. One set of structures represents a larger group of KS domains from both canonical and AT-less type I PKSs that accept amino acid-containing substrates. One structure has a partial AT-domain, revealing the structural consequences of a type I PKS KS evolving into an AT-less type I PKS KS. These structures highlight the structural diversity within the AT-less type I PKS KS family, and most important, provide a unique opportunity to study the molecular evolution of substrate specificity within the type I PKSs.

  7. Well-formedness and typing rules for UML Composite Structures

    Dragomir, Iulia

    2010-01-01

    Starting from version 2.0, UML introduced hierarchical composite structures, which are an expressive way of defining complex software architectures, but which have a very loosely defined semantics in the standard. In this paper we propose a set of consistency rules that disambiguate the meaning of UML composite structures. Our primary goal was to have an operational model of composite structures for the OMEGA UML profile, an executable profile dedicated to the formal specification and validation of real-time systems, developed in a past project to which we contributed. However, the rules and principles stated here are applicable to other hierarchical component models based on the same concepts, such as SysML. The presented ruleset is supported by an OCL formalization which is described in this report. This formalization was applied on different complex models for the evaluation and validation of the proposed principles.

  8. A New Type Method for the Structured Variational Inequalities Problem

    Chengjiang Yin

    2013-01-01

    In this paper, we present an algorithm for solving the structured variational inequality problem, and prove the global convergence of the new method without carrying out any line search technique, and the global R-convergence rate are also given under the suitable conditions.

  9. The Structure of Workaholism and Types of Workaholic

    Malinowska Diana; Tokarz Aleksandra

    2014-01-01

    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...

  10. Reciprocal transformations and local Hamiltonian structures of hydrodynamic type systems

    Abenda, Simonetta

    2008-01-01

    We start from a hyperbolic DN hydrodynamic type system of dimension $n$ which possesses Riemann invariants and we settle the necessary conditions on the conservation laws in the reciprocal transformation so that, after such a transformation of the independent variables, one of the metrics associated to the initial system be flat. We prove the following statement: let $n\\ge 3$ in the case of reciprocal transformations of a single independent variable or $n\\ge 5$ in the case of transformations ...

  11. The Gd{sub 14}Ag{sub 51} structure type and its relation to some complex amalgam structures

    Tambornino, Frank; Sappl, Jonathan; Hoch, Constantin, E-mail: constantin.hoch@cup.uni-muenchen.de

    2015-01-05

    Highlights: • The Gd{sub 14}Ag{sub 51} structure type has been revisited on the basis of single crystal diffraction data. • Symmetry analysis from electron density and TEM shows the space group P6/m to be true. • Gd{sub 14}Ag{sub 51} shows good metallic behaviour. • Structure relations to alkali, alkaline-earth and rare-earth metal amalgams can be established. • Complexity values for the RE{sub 14}Ag{sub 51} structure family were calculated. - Abstract: A plethora of binary and ternary intermetallic compounds has been assigned to the Gd{sub 14}Ag{sub 51} structure type, crystallising in the hexagonal system (space group P6/m, a = 1264.30(18) pm, c = 933.58(11) pm for Gd{sub 14}Ag{sub 51}). Starting in the late 1960s, much work has been invested in the structural elucidation of these crystal structures. However, reliable single crystal data are scarce, and most structure type assignments have been performed merely on the basis of powder data. We have redetermined four representatives of the binary RE{sub 14}Ag{sub 51} structure type (RE = Y, Ce, Gd, Tb) with modern high-precision single crystal X-ray methods. The assignment of the Gd{sub 14}Ag{sub 51} structure type to space group P6/m was additionally verified by careful analysis of high resolution transmission electron micrographs. We emphasise the close relation of the Gd{sub 14}Ag{sub 51} structure type to the structures of some recently described amalgams of similar composition focussing on disorder phenomena and structural complexity. Furthermore, we provide detailed information on synthesis as well as electrical and magnetic properties for Gd{sub 14}Ag{sub 51}, the parent compound of this structure family.

  12. A Type-Theoretic Approach to Structural Resolution

    Fu, Peng; Komendantskaya, Ekaterina

    2015-01-01

    Structural resolution (or S-resolution) is a newly proposed alternative to SLD-resolution that allows a systematic separation of derivations into term-matching and unification steps. Productive logic programs are those for which term-matching reduction on any query must terminate. For productive programs with coinductive meaning, finite term-rewriting reductions can be seen as measures of observation in an infinite derivation. Ability of handling corecursion in a productive way is an attracti...

  13. The structural stability of wild-type horse prion protein.

    Zhang, Jiapu

    2011-10-01

    Prion diseases (e.g. Creutzfeldt-Jakob disease (CJD), variant CJD (vCJD), Gerstmann-Straussler-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 β2-α2 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 horse prion protein. Thus, the region of β2-α2 loop might be a potential drug target region. Besides this very important salt bridge, other four important salt bridges GLU196-ARG156-HIS187, ARG156-ASP202 and GLU211-HIS177 are also found to greatly contribute to the structural stability of horse prion protein. Rich databases of salt bridges, hydrogen bonds and hydrophobic contacts for horse prion protein can be found in this paper. PMID:21875155

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

    Hovorka, Miloš; Mika, Filip; Frank, Luděk; 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 ČR GP102/09/P543; GA AV ČR IAA100650803 Institutional research plan: CEZ:AV0Z20650511 Keywords : n-type substrate * SEM * PEEM * doping levels Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering

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

    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.)

  16. Fire Protection in Various Types of Wooden Structures

    Gašpercová Stanislava

    2015-05-01

    Full Text Available Design of new modern systems for low energy efficient construction in a passive, zero standard or energy-autonomous buildings, as well as the increased popularity of solid wood construction means intervention into the very structure of its statics, building physics, but also fire properties. Some prototype design solutions are not verified whether the tests, by good computational analysis or verification of long-term use of the building. In the context of changing standards in building design, new approaches are needed. If in wooden buildings the potential risk of fire is higher than other buildings, we need special methods, materials and practical skills.

  17. Fire Protection in Various Types of Wooden Structures

    Gašpercová, Stanislava; Makovická Osvaldová, Linda

    2015-05-01

    Design of new modern systems for low energy efficient construction in a passive, zero standard or energy-autonomous buildings, as well as the increased popularity of solid wood construction means intervention into the very structure of its statics, building physics, but also fire properties. Some prototype design solutions are not verified whether the tests, by good computational analysis or verification of long-term use of the building. In the context of changing standards in building design, new approaches are needed. If in wooden buildings the potential risk of fire is higher than other buildings, we need special methods, materials and practical skills.

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

    O. R. Nandagopan; Sameer Abdul Azeez; C. G. Nandakumar

    2013-01-01

    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 fr...

  19. Structural Analysis of Botulinum Neurotoxin Type G Receptor Binding

    Schmitt, John; Karalewitz, Andrew; Benefield, Desire A.; Mushrush, Darren J.; Pruitt, Rory N.; Spiller, Benjamin W.; Barbieri, Joseph T.; Lacy, D. Borden (Vanderbilt); (MCW)

    2010-10-19

    Botulinum neurotoxin (BoNT) binds peripheral neurons at the neuromuscular junction through a dual-receptor mechanism that includes interactions with ganglioside and protein receptors. The receptor identities vary depending on BoNT serotype (A-G). BoNT/B and BoNT/G bind the luminal domains of synaptotagmin I and II, homologous synaptic vesicle proteins. We observe conditions under which BoNT/B binds both Syt isoforms, but BoNT/G binds only SytI. Both serotypes bind ganglioside G{sub T1b}. The BoNT/G receptor-binding domain crystal structure provides a context for examining these binding interactions and a platform for understanding the physiological relevance of different Syt receptor isoforms in vivo.

  20. Structure and Dynamics of Early-Type Galaxies

    Tremblay, Joseph Benoi T.

    1997-06-01

    We present several data-based studies of the dynamics and morphology of early-type galaxies, with an emphasis on the distribution of dark matter. In the first study (Chapter 2), we attempt to map the distribution of dark matter around the giant elliptical galaxy M87 using the velocities of 43 globular clusters reported by Mould et al. (AJ, 99, 1823 (1990)). Assuming spherical symmetry in configuration and velocity space, we find a most likely, power-law dependence of dark matter density on radius of p(r) ∝ r-1.8, where the exponent lies between 0.2 and 3.0 with 99% confidence. We estimate that a sample of roughly 200 velocities would be required to determine the mass-density exponent to a precision of ±0.5. In the second part of the thesis (Chapters 3 and 4), we present the results of a study of the galaxy pair NGC 3384 (SB0)/NGC 3379 (E1) in the Leo I group using the Rutgers Fabry-Perot interferometer. We measured the velocities of 148 planetary nebulae around the two galaxies from the Doppler-shifted (OIII) emission line. The planetary nebula system in NGC 3384 exhibits an orderly rotation field aligned with the photometric axes of the galaxy. The mass of NGC 3384 is infered to be 1.6 x 1011 M⊙ within our last data point at 13 kpc. In the case of NGC 3379, no significant rotation of the planetary nebula system was detected. The mass of NGC 3379 is estimated to be 3 x 1011 M⊙ within 9 kpc, assuming a spherical, isotropic distribution of nebulae. The third part of the thesis (Chapters 5 and 6) consists of a fully nonparametric study of the distribution of elliptical galaxy intrinsic shapes. If elliptical galaxies of all intrinsic luminosities are considered as a single group, the frequency function of intrinsic shapes is found to be inconsistent with the axisymmetric hypothesis at the 99% level. However, many triaxial shape distributions can be found that reproduce the data. If elliptical galaxies are segregated according to intrinsic luminosity, we find a

  1. The differentiation of amnestic type MCI from the non-amnestic types by structural MRI

    Gábor eCsukly

    2016-03-01

    Full Text Available Introduction: While amnestic mild cognitive impairment (aMCI and non-amnestic mild cognitive impairment (naMCI are theoretically different entities, only a few investigations studied the structural brain differences between these subtypes of mild cognitive impairment. The aim of the study was to find the structural differences between aMCI and naMCI, and to replicate previous findings on the differentiation between aMCI and healthy controls.Methods: Altogether 62 aMCI, naMCI, and healthy control subjects were included into the study based on the Petersen criteria. All patients underwent a routine brain MR examination, and a detailed neuropsychological examination.Results: The sizes of the hippocampus, the entorhinal cortex and the amygdala were decreased in aMCI relative to naMCI and to controls. Furthermore the cortical thickness of the entorhinal cortex, the fusiform gyrus, the precuneus and the isthmus of the cingulate gyrus were significantly decreased in aMCI relative to naMCI and healthy controls. The largest differences relative to controls were detected for the volume of the hippocampus (18% decrease vs. controls and the cortical thickness (20% decrease vs. controls of the entorhinal cortex: 1.6 and 1.4 in terms of Cohen’s d. Only the volume of the precuneus were decreased in the naMCI group (5% decrease compared to the control subjects: 0.9 in terms of Cohen’s d. Significant between group differences were also found in the neuropsychological test results: a decreased anterograde, retrograde memory, and category fluency performance was detected in the aMCI group relative to controls and naMCI subjects. Subjects with naMCI showed decreased letter fluency relative to controls, while both MCI groups showed decreased executive functioning relative to controls as measured by the Trail Making test part B. Memory performance in the aMCI group and in the entire sample correlated with the thickness of the entorhinal cortex and with the volume

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

    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. Vertical and Horizontal Vegetation Structure across Natural and Modified Habitat Types at Mount Kilimanjaro.

    Rutten, Gemma; Ensslin, Andreas; Hemp, Andreas; Fischer, Markus

    2015-01-01

    In most habitats, vegetation provides the main structure of the environment. This complexity can facilitate biodiversity and ecosystem services. Therefore, measures of vegetation structure can serve as indicators in ecosystem management. However, many structural measures are laborious and require expert knowledge. Here, we used consistent and convenient measures to assess vegetation structure over an exceptionally broad elevation gradient of 866-4550 m above sea level at Mount Kilimanjaro, Tanzania. Additionally, we compared (human)-modified habitats, including maize fields, traditionally managed home gardens, grasslands, commercial coffee farms and logged and burned forests with natural habitats along this elevation gradient. We distinguished vertical and horizontal vegetation structure to account for habitat complexity and heterogeneity. Vertical vegetation structure (assessed as number, width and density of vegetation layers, maximum canopy height, leaf area index and vegetation cover) displayed a unimodal elevation pattern, peaking at intermediate elevations in montane forests, whereas horizontal structure (assessed as coefficient of variation of number, width and density of vegetation layers, maximum canopy height, leaf area index and vegetation cover) was lowest at intermediate altitudes. Overall, vertical structure was consistently lower in modified than in natural habitat types, whereas horizontal structure was inconsistently different in modified than in natural habitat types, depending on the specific structural measure and habitat type. Our study shows how vertical and horizontal vegetation structure can be assessed efficiently in various habitat types in tropical mountain regions, and we suggest to apply this as a tool for informing future biodiversity and ecosystem service studies. PMID:26406985

  4. New series of triple molybdates AgA3R(MoO4)5 (A=Mg, R=Cr, Fe; A=Mn, R=Al, Cr, Fe, Sc, In) with framework structures and mobile silver ion sublattices

    Kotova, Irina Yu.; Solodovnikov, Sergey F.; Solodovnikova, Zoya A.; Belov, Dmitry A.; Stefanovich, Sergey Yu.; Savina, Aleksandra A.; Khaikina, Elena G.

    2016-06-01

    Triple molybdates AgA3R(MoO4)5 (A=Mg, R=Cr, Fe; A=Mn, R=Al, Cr, Fe, Sc, In) of the NaMg3In(MoO4)5 type were synthesized and single crystals of AgMg3R(MoO4)5 (R=Cr, Fe) were grown. In their structures, the MoO4 tetrahedra, pairs and trimers of edge-shared (Mg, R)O6 octahedra are connected by common vertices to form a 3D framework. Large framework cavities involve Ag+ cations disordered on three nearby positions with CN=3+1 or 4+1. Alternating (Mg, R)O6 octahedra and MoO4 tetrahedra in the framework form quadrangular windows penetrable for Ag+ at elevated temperatures. Above 653-673 K, the newly obtained molybdates demonstrate abrupt reduction of the activation energy to 0.4-0.6 eV. At 773 K, AgMg3Al(MoO4)5 shows electric conductivity 2.5·10-2 S/cm and Ea=0.39 eV compatible with characteristics of the best ionic conductors of the NASICON type.

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

    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.

  6. Photovoltaic properties of ZnO nanorods/p-type Si heterojunction structures

    Rafal Pietruszka

    2014-02-01

    Full Text Available Selected properties of photovoltaic (PV structures based on n-type zinc oxide nanorods grown by a low temperature hydrothermal method on p-type silicon substrates (100 are investigated. PV structures were covered with thin films of Al doped ZnO grown by atomic layer deposition acting as transparent electrodes. The investigated PV structures differ in terms of the shapes and densities of their nanorods. The best response is observed for the structure containing closely-spaced nanorods, which show light conversion efficiency of 3.6%.

  7. Ultralight X-type lattice sandwich structure(I):Concept,fabrication and experimental characterization

    ZHANG QianCheng; HAN YunJie; CHEN ChangQing; LU TianJian

    2009-01-01

    A new type of ultra-lightweight metallic lattice structure(named as the X-type structure)is reported.This periodic structure was formed by two groups of staggered struts in the traditional pyramid structure,and fabricated by folding expanded metal sheet along rows of offset nodes and then brazing the folded structure(as the core)with top and bottom facesheets to form sandwich panels.The out-ofplane compressive and shear properties of the X-type lattice sandwich structure were investigated experimentally and compared to those of the sandwich having a pyramidal truss core.It is found that the formation of the 2-dimensional staggered nodes can effectively make the X-type structure more resistant to inelastic and plastic buckling under both compression and shear loading than the pyramidal lattice truss.Obtained results show that the compressive and shear peak strengths of the X-type lattice structure are about 30% higher than those of the pyramidal lattice truss having the same relative density.

  8. Some Relationships Between Psychological Structure, Educational Beliefs, and Teaching Strategies in Three Types of Teacher Trainees.

    Nier, Charles J.

    This study investigated systematic relationships among teacher personality types (Ambitious, Conscientious, and Indulgent), preservice educational beliefs, and intern classroom practices. The investigation traced the theoretical and empirical linkage from personality structure though educational ideology and finally to perceptions of teacher…

  9. Life Comparative Analysis of Energy Consumption and CO2 Emissions of Different Building Structural Frame Types

    Sangyong Kim; Joon-Ho Moon; Yoonseok Shin; Gwang-Hee Kim; Deok-Seok Seo

    2013-01-01

    The objective of this research is to quantitatively measure and compare the environmental load and construction cost of different structural frame types. Construction cost also accounts for the costs of CO2 emissions of input materials. The choice of structural frame type is a major consideration in construction, as this element represents about 33% of total building construction costs. In this research, four constructed buildings were analyzed, with these having either reinforced concrete (R...

  10. The infrared spectrum and structure of the type I complex of silver and DNA.

    DiRico, D E; Keller, P B; Hartman, K. A.

    1985-01-01

    Infrared spectroscopy was used to study films of the type I complex of Ag+ and DNA as a function of hydration with the following conclusions. Ag+ binds to guanine residues but not to cytosine or thymine residues. Cytosine becomes protonated as Ag+ binds to guanine. (These conclusions confirm previous models.) The type I complex remains in the B family of structures with slight modifications of the sugar-phosphate geometry. This modified B structure remains stable at lower values of hydration ...

  11. Molecular dynamics of folding of secondary structures in Go-type models of proteins

    Hoang, Trinh Xuan; Cieplak, Marek

    1999-01-01

    We consider six different secondary structures of proteins and construct two types of Go-type off-lattice models: with the steric constraints and without. The basic aminoacid-aminoacid potential is Lennard Jones for the native contacts and a soft repulsion for the non-native contacts. The interactions are chosen to make the target secondary structure be the native state of the system. We provide a thorough equilibrium and kinetic characterization of the sequences through the molecular dynamic...

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

    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.

  13. Best Entry Points for Structured Document Retrieval - Part II: Types, Usage and Effectiveness

    Reid, Jane; Lalmas, Mounia; Finesilver, Karen; Hertzum, Morten

    2006-01-01

    structured documents. This paper examines the concept of best entry points, which are document components from which the user can browse to obtain optimal access to relevant document components. It investigates at the types of best entry points in structured document retrieval, and their usage and...... effectiveness in real information search tasks....

  14. Paired structures, imprecision types and two-level knowledge representation by means of opposites

    Rodríguez, J. Tinguaro; Franco de los Ríos, Camilo; Gómez, Daniel;

    2016-01-01

    to evaluate the verification of the former. We study this issue by means of the consideration of different paired structures at each level. We also pay attention at how different types of fuzziness may be introduced in these paired structures to model imprecision and lack of knowledge. As a...

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

    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

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

    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.

  17. Structure and fluid evolution of Yili basin and their relation to sandstone type uranium mineralization

    Based on the summary of strata and structure distribution of Yili basin, the relation of structure and fluid evolution to sandstone type ur alum mineraliation are analyzed. It is found that uranium mineralization in Yili basin experienced ore hosting space forming, pre-alteration of hosting space, hosting space alteration and uranium formation stages. (authors)

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

    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…

  19. The N=4 effective action of type IIA supergravity compactified on SU(2)-structure manifolds

    Danckaert, Thomas; Martínez-Pedrera, Danny; Spanjaard, Bastiaan; Triendl, Hagen

    2011-01-01

    We study compactifications of type IIA supergravity on six-dimensional manifolds with SU(2) structure and compute the low-energy effective action in terms of the non-trivial intrinsic torsion. The consistency with gauged N=4 supergravity is established and the gauge group is determined. Depending on the structure of the intrinsic torsion, antisymmetric tensor fields can become massive.

  20. Bismuth zinc vanadate, BiZn{sub 2}VO{sub 6}: New crystal structure type and electronic structure

    Eliziario Nunes, Sayonara [Department of Chemistry, Durham University, South Road, Durham DH1 3LE (United Kingdom); Department of Materials Engineering, Federal University of São Carlos, 13565-905 São Carlos, SP (Brazil); Wang, Chun-Hai; So, Karwei; Evans, John S.O. [Department of Chemistry, Durham University, South Road, Durham DH1 3LE (United Kingdom); Evans, Ivana Radosavljević, E-mail: ivana.radosavljevic@durham.ac.uk [Department of Chemistry, Durham University, South Road, Durham DH1 3LE (United Kingdom)

    2015-02-15

    We report a combined experimental and computational study of the crystal structure and electronic properties of bismuth zinc vanadate, BiZn{sub 2}VO{sub 6}, known for its visible light photocatalytic activity. The crystal structure has been solved from laboratory powder X-ray diffraction data using the repeated minimisations from random starting values method. BiZn{sub 2}VO{sub 6} adopts a new structure type, based on the following building blocks: corner- and edge-sharing ZnO{sub 4} tetrahedra, ZnO{sub 6} octahedra and VO{sub 4} tetrahedra, and Bi{sub 2}O{sub 12} dimers. It is the only known member of the BiM{sub 2}AO{sub 6} (M=Pb, Ca, Cd, Mn, Zn, Mg, Cu; A=V, P, As) family which does not appear to be structurally closely related to others. The electronic structure of BiZn{sub 2}VO{sub 6}, calculated by DFT methods, shows that it is an indirect gap semiconductor with a calculated band gap of 1.6 eV, which compares favourably to the experimentally measured value of 2.4 eV. - Graphical abstract: The crystal structure of BiZn{sub 2}VO{sub 6}, a new structure type in the BiM{sub 2}AO{sub 6} (M=Mg, Ca, Cd, Cu, Pb, Mn, Zn; A=V, P, As) family. - Highlights: • Structure solution from PXRD data by repeated minimisations from random starting values. • New structure type in the BiM{sub 2}AO{sub 6} (M=Pb, Ca, Cd, Mn, Zn, Mg, Cu; A=V, P, As) family. • Electronic structure calculation.

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

    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.

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

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

  3. Structural properties of the zircon- and scheelite-type phases of YVO4 at high pressure

    Wang, X.; Loa, I.; Syassen, K.; Hanfland, M.; Ferrand, B.

    2004-08-01

    The laser host material yttrium orthovanadate YVO4 with a tetragonal zircon-type structure has been studied by angle-dispersive powder x-ray diffraction in a diamond anvil cell up to 26GPa (T=300K) . In situ diffraction confirms that the compound undergoes a nonreversible transformation to a scheelite-type structure at a pressure of 8.5GPa . The equations of state of the zircon and scheelite phases and changes in internal structural parameters are reported. The effect of pressure on the distorted tetrahedral and dodecahedral coordinations of the V and Y ions, respectively, is discussed.

  4. Damage identification in shear-type structures using a proper orthogonal decomposition approach

    Wang, Dansheng; Xiang, Wei; Zeng, Peng; Zhu, Hongping

    2015-10-01

    Proper orthogonal modes (POMs) obtained through proper orthogonal decomposition (POD), as a statistical pattern analysis technique, have been physically demonstrated to represent the dominant structure of the dynamic response data in previous study. In this paper, a novel POMs-based damage identification approach for shear-type buildings is developed. First, POMs of acceleration dynamic response of a shear-type building under Gauss White Noise (GWN) ground motion are obtained using singular value decomposition; then, the dominant POMs of acceleration response are used to identify the damage locations and severities through particle swarm optimization (PSO) algorithm. This proposed approach is applied to two three-story shear-type buildings in numerical simulation and a three-story shear-type frame in experimental study. The results demonstrate that the locations and severities of structural damage in shear-type buildings can be effectively identified by using the proposed method.

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

    Nenadović 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.

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

    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.

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

    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...

  8. An Integrated Structural Strength Analysis Method for Spar Type Floating Wind Turbine

    胡志强; 刘毅; 王晋

    2016-01-01

    An integrated structural strength analysis method for a Spar type floating wind turbine is proposed in this paper, and technical issues related to turbine structure modeling and stress combination are also addressed. The NREL-5MW “Hywind” Spar type wind turbine is adopted as study object. Time-domain dynamic coupled simulations are performed by a fully-coupled aero-hydro-servo-elastic tool, FAST, on the purpose of obtaining the dynamic characteristics of the floating wind turbine, and determining parameters for design load cases of finite element calculation. Then design load cases are identified, and finite element analyses are performed for these design load cases. The structural stresses due to wave-induced loads and wind-induced loads are calculated, and then combined to assess the structural strength of the floating wind turbine. The feasibility of the proposed structural strength analysis method for floating wind turbines is then validated.

  9. An integrated structural strength analysis method for Spar type floating wind turbine

    Hu, Zhi-qiang; Liu, Yi; Wang, Jin

    2016-04-01

    An integrated structural strength analysis method for a Spar type floating wind turbine is proposed in this paper, and technical issues related to turbine structure modeling and stress combination are also addressed. The NREL-5MW "Hywind" Spar type wind turbine is adopted as study object. Time-domain dynamic coupled simulations are performed by a fully-coupled aero-hydro-servo-elastic tool, FAST, on the purpose of obtaining the dynamic characteristics of the floating wind turbine, and determining parameters for design load cases of finite element calculation. Then design load cases are identified, and finite element analyses are performed for these design load cases. The structural stresses due to wave-induced loads and wind-induced loads are calculated, and then combined to assess the structural strength of the floating wind turbine. The feasibility of the proposed structural strength analysis method for floating wind turbines is then validated.

  10. Life Comparative Analysis of Energy Consumption and CO2 Emissions of Different Building Structural Frame Types

    Sangyong Kim

    2013-01-01

    Full Text Available The objective of this research is to quantitatively measure and compare the environmental load and construction cost of different structural frame types. Construction cost also accounts for the costs of CO2 emissions of input materials. The choice of structural frame type is a major consideration in construction, as this element represents about 33% of total building construction costs. In this research, four constructed buildings were analyzed, with these having either reinforced concrete (RC or steel (S structures. An input-output framework analysis was used to measure energy consumption and CO2 emissions of input materials for each structural frame type. In addition, the CO2 emissions cost was measured using the trading price of CO2 emissions on the International Commodity Exchange. This research revealed that both energy consumption and CO2 emissions were, on average, 26% lower with the RC structure than with the S structure, and the construction costs (including the CO2 emissions cost of the RC structure were about 9.8% lower, compared to the S structure. This research provides insights through which the construction industry will be able to respond to the carbon market, which is expected to continue to grow in the future.

  11. Life comparative analysis of energy consumption and CO₂ emissions of different building structural frame types.

    Kim, Sangyong; Moon, Joon-Ho; Shin, Yoonseok; Kim, Gwang-Hee; Seo, Deok-Seok

    2013-01-01

    The objective of this research is to quantitatively measure and compare the environmental load and construction cost of different structural frame types. Construction cost also accounts for the costs of CO₂ emissions of input materials. The choice of structural frame type is a major consideration in construction, as this element represents about 33% of total building construction costs. In this research, four constructed buildings were analyzed, with these having either reinforced concrete (RC) or steel (S) structures. An input-output framework analysis was used to measure energy consumption and CO₂ emissions of input materials for each structural frame type. In addition, the CO₂ emissions cost was measured using the trading price of CO₂ emissions on the International Commodity Exchange. This research revealed that both energy consumption and CO₂ emissions were, on average, 26% lower with the RC structure than with the S structure, and the construction costs (including the CO₂ emissions cost) of the RC structure were about 9.8% lower, compared to the S structure. This research provides insights through which the construction industry will be able to respond to the carbon market, which is expected to continue to grow in the future. PMID:24227998

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

    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.

  13. Cryo-EM structures of two bovine adenovirus type 3 intermediates

    Adenoviruses (Ads) infect hosts from all vertebrate species and have been investigated as vaccine vectors. We report here near-atomic structures of two bovine Ad type 3 (BAd3) intermediates obtained by cryo-electron microscopy. A comparison between the two intermediate structures reveals that the differences are localized in the fivefold vertex region, while their facet structures are identical. The overall facet structure of BAd3 exhibits a similar structure to human Ads; however, BAd3 protein IX has a unique conformation. Mass spectrometry and cryo-electron tomography analyses indicate that one intermediate structure represents the stage during DNA encapsidation, whilst the other intermediate structure represents a later stage. These results also suggest that cleavage of precursor protein VI occurs during, rather than after, the DNA encapsidation process. Overall, our results provide insights into the mechanism of Ad assembly, and allow the first structural comparison between human and nonhuman Ads at backbone level. - Highlights: • First structure of bovine adenovirus type 3. • Some channels are located at the vertex of intermediate during DNA encapsidation. • Protein IX exhibits a unique conformation of trimeric coiled–coiled structure. • Cleavage of precursor protein VI occurs during the DNA encapsidation process

  14. Cryo-EM structures of two bovine adenovirus type 3 intermediates

    Cheng, Lingpeng; Huang, Xiaoxing; Li, Xiaomin [National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101 (China); Xiong, Wei [State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Luo-jia-shan, Wuhan, Hubei 430072 (China); Sun, Wei; Yang, Chongwen; Zhang, Kai; Wang, Ying [National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101 (China); Liu, Hongrong [College of Physics and Information Science, Hunan Normal University, Changsha, Hunan 410081 (China); Huang, Xiaojun; Ji, Gang; Sun, Fei [National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101 (China); Zheng, Congyi, E-mail: cctcc202@whu.edu.cn [State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Luo-jia-shan, Wuhan, Hubei 430072 (China); Zhu, Ping, E-mail: zhup@ibp.ac.cn [National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101 (China)

    2014-02-15

    Adenoviruses (Ads) infect hosts from all vertebrate species and have been investigated as vaccine vectors. We report here near-atomic structures of two bovine Ad type 3 (BAd3) intermediates obtained by cryo-electron microscopy. A comparison between the two intermediate structures reveals that the differences are localized in the fivefold vertex region, while their facet structures are identical. The overall facet structure of BAd3 exhibits a similar structure to human Ads; however, BAd3 protein IX has a unique conformation. Mass spectrometry and cryo-electron tomography analyses indicate that one intermediate structure represents the stage during DNA encapsidation, whilst the other intermediate structure represents a later stage. These results also suggest that cleavage of precursor protein VI occurs during, rather than after, the DNA encapsidation process. Overall, our results provide insights into the mechanism of Ad assembly, and allow the first structural comparison between human and nonhuman Ads at backbone level. - Highlights: • First structure of bovine adenovirus type 3. • Some channels are located at the vertex of intermediate during DNA encapsidation. • Protein IX exhibits a unique conformation of trimeric coiled–coiled structure. • Cleavage of precursor protein VI occurs during the DNA encapsidation process.

  15. An efficient algorithm for planar drawing of RNA structures with pseudoknots of any type.

    Byun, Yanga; Han, Kyungsook

    2016-06-01

    An RNA pseudoknot is a tertiary structural element in which bases of a loop pair with complementary bases are outside the loop. A drawing of RNA secondary structures is a tree, but a drawing of RNA pseudoknots is a graph that has an inner cycle within a pseudoknot and possibly outer cycles formed between the pseudoknot and other structural elements. Visualizing a large-scale RNA structure with pseudoknots as a planar drawing is challenging because a planar drawing of an RNA structure requires both pseudoknots and an entire structure enclosing the pseudoknots to be embedded into a plane without overlapping or crossing. This paper presents an efficient heuristic algorithm for visualizing a pseudoknotted RNA structure as a planar drawing. The algorithm consists of several parts for finding crossing stems and page mapping the stems, for the layout of stem-loops and pseudoknots, and for overlap detection between structural elements and resolving it. Unlike previous algorithms, our algorithm generates a planar drawing for a large RNA structure with pseudoknots of any type and provides a bracket view of the structure. It generates a compact and aesthetic structure graph for a large pseudoknotted RNA structure in O([Formula: see text]) time, where n is the number of stems of the RNA structure. PMID:26932273

  16. Ultralight X-type lattice sandwich structure (Ⅱ):Micromechanics modeling and finite element analysis

    2009-01-01

    The methods of homogenization and finite elements are employed to predict the effective elastic constants and stress-strain responses of a new type of lattice structure,the X-structure proposed by the authors in a companion paper. It is shown that in most cases the predictions by the equivalent homogenization theory agree well with the experimental and 3-dimensional finite element calculated results. The theoretical and numerical study supports the argument that the X-structure is superior to the pyramid lattice structure in terms of mechanical strength.

  17. Ultralight X-type lattice sandwich structure (Ⅱ): Micromechanics modeling and finite element analysis

    ZHANG QianCheng; CHEN AiPing; CHEN ChangQing; LU TianJian

    2009-01-01

    The methods of homogenization and finite elements are employed to predict the effective elastic con-stants and stress-strain responses of a new type of lattice structure, the X-structure proposed by the authors in a companion paper. It is shown that in most cases the predictions by the equivalent ho-mogenization theory agree well with the experimental and 3-dimensional finite element calculated re-sults. The theoretical and numerical study supports the argument that the X-structure is superior to the pyramid lattice structure in terms of mechanical strength.

  18. Response of Box-Type Structures Under Internal-Blast Loading

    WANG Zhongqi; WU Jianguo; BAI Chunhua; LU Yong

    2006-01-01

    The tests of box-type structures under internal-blast loading are carried out.Then a numerical analysis of the test structures is done using a fully coupled numerical finite element model.The break-up process of the structure is simulated.The failure modes of the simulated structure agree well with the experimental results.The effects of the size of the reinforcing bars and the detailing of connections among the rebars in the concrete on the throw velocity of the fragments are discussed.

  19. Determination of a new structure type in the Sc–Fe–Ge–Sn system

    Highlights: ► A new structure type with the composition Sc4Fe5Ge6.10(3)Sn1.47(2). ► Crystallizes in the space group Immm (No. 71, oI144). ► Sample obtained using a reactive Sn flux. ► Electronic structure calculations indicate polar intermetallic bonding network. - Abstract: A new structure type has been discovered in the system Sc–Fe–Ge–Sn by employing Sn as a flux medium. According to single crystal X-ray diffraction, the new structure has a composition of Sc4Fe5Ge6.10(3)Sn1.47(2) and crystallizes in the space group Immm (No. 71, oI144) with lattice parameters of a = 5.230(1) Å, b = 13.467(3) Å, and c = 30.003(6) Å. The structure is composed of square anti-prismatic clusters that are condensed into zig-zag chains along the [0 1 0] direction. These chains are further condensed through a split Sn/Ge position, forming a three-dimensional network. Magnetization measurements indicate an antiferromagnetic phase transition near 240 K. Electronic structure calculations identified the most favorable bonding network in this new system. Using crystal orbital Hamilton population (COHP) curves and their integrated values (ICOHP), a polar intermetallic bonding network involving Sc–Ge as well as Fe–Sn and Fe–Ge contacts can be assigned to this new structure type.

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

    Shahpiri, Azar; Svensson, Birte; Finnie, Christine

    2009-01-01

    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...

  1. Direct observation and structural characterization of natural and metal ion-exchanged HEU-type zeolites

    Filippousi, Maria; Turner, Stuart; Katsikini, Maria; Pinakidou, Fani; Zamboulis, Demetris; Pavlidou, Eleni; Tendeloo, van, G.

    2015-01-01

    Abstract: The atomic structure of natural HEU-type zeolite and two ion-exchanged variants of the zeolite, Ag+ (Ag-HEU) and Zn2+ (Zn-HEU) ion exchanged HEU-type zeolites, are investigated using advanced transmission electron microscopy techniques in combination with X-ray powder diffraction and X-ray absorption fine structure measurements. In both ion-exchanged materials, loading of the natural HEU zeolite is confirmed. Using low-voltage, aberration-corrected transmission electron microscopy a...

  2. Can a half-metallic zincblende-type structure be stabilized via epitaxy?

    ZHAO, YU-JUN; Zunger, Alex

    2004-01-01

    The need for spin-injectors having the same zincblende-type crystal structure as conventional semiconductor substrates has created significant interests in theoretical predictions of possible metastable ``half-metallic'' zincblende ferromagnets, which are normally more stable in other structure-types, e.g., NiAs. Such predictions were based in the past on differences $\\Delta_{\\rm bulk}$ in the total-energies of the respective {\\em bulk} crystal forms (zincblende and NiAs). We show here that t...

  3. Structure and Composition of Protein Bodies from Wild-Type and High-Lysine Barley Endosperm

    Ingversen, J.

    1975-01-01

    granular component. Particles with the same structure were present in the protein body preparation from the mutant, where, however, the granular component was the most prominent. Amino-acid composition and SDS-polyacrylamide gel electrophoresis of the proteins from the protein body preparation revealed......-polyacrylamidegel electrophoresis. Sections through pellets of isolated protein bodies from both the mutant and the wild type revealed protein body structures corresponding with those observed in sections through the intact starchy endosperms. The majority of the wild-type protein bodies was homogeneous spheres accompanied with a...

  4. Equivalent linearization method for limit cycle flutter analysis of plate-type structure in axial flow

    The responses and limit cycle flutter of a plate-type structure with cubic stiffness in viscous flow were studied. The continuous system was dispersed by utilizing Galerkin Method. The equivalent linearization concept was performed to predict the ranges of limit cycle flutter velocities. The coupled map of flutter amplitude-equivalent linear stiffness-critical velocity was used to analyze the stability of limit cycle flutter. The theoretical results agree well with the results of numerical integration, which indicates that the equivalent linearization concept is available to the analysis of limit cycle flutter of plate-type structure. (authors)

  5. Ce2Ir5B2, a new structure type of ternary borides

    The crystal structure of a new ternary boride Ce2Ir5B2, space group R3-bar m, a=5.477(2) A, c=31.518(5) A, Z=6, V=818.79 A, was refined down to R=0.0484, wR2=0.1211 from single crystal X-ray diffraction data. This is the first representative of a new structure type of intermetallic compounds (an ordered variant of the binary Er2Co7 compound). The structure of Ce2Ir5B2 is the stacking variant of the MgCu2- and CeCo3B2-type slabs and belongs to the structural series with the general formula R2+nM4+3nX2n (n=2)

  6. The indentification of Jueluotage V-type structure in Xinjiang and its orderness

    Based on the interpretation of satellite image and field checking in Jueluotage area, Xinjiang, it is thought that the sublatitudinal arc fault zones have been formed since Mesozoic through the evolution of the NWW-trending and NEE-trending faults occurring in pre-Mesozoic time. These three sets of faults comprise the Jueluotage 'V-type structure' formed by the NW-trending structural stress field and drastically activated since Neocene. The Jueluotage V-type structure is expressed in time as an ordered process, and in space as an ordered arrangement and an ordered evolution direction, and characterizes the Information Ordered Series (IOS) of the evolution process of fault structure. (authors)

  7. A Study of the Types of Organizational Structure in Venezuelan University Institutes

    Rafael Antonio Pertuz Belloso

    2013-12-01

    Full Text Available This study aimed at identifying the type of organizational structure of Venezuelan university institutes. It is a field investigation of a descriptive nature with a non-experimental transactional field design. We worked with a population sample consisting of a director, assistant directors, academic assistant directors and eighty-eight teachers from technological institutes in Cabimas and Maracaibo in Venezuela. A survey, in the form of a questionnaire, was used as the data collection technique, which included 24 items, validated by 5 experts, with Cronbach Alpha reliability of 0.93. The data analysis technique utilized was the percentage frequency distribution. The results indicated the coexistence of bureaucratic structural typologies; departmental and simple. An implementation of a structural migration strategy to the implementation of a matrix-type structure is recommended.

  8. Experimental component Mode Synthesis Applied to the Solar Array Type Structure

    Komatsu, Keiji; Sano, Masaaki; SANBONGI, Shigeo; Takashi Kai; TODA, Susumu; 小松, 敬治; 佐野, 政明; 三本木, 茂夫; 甲斐, 高志; 戸田, 勧

    1988-01-01

    A component mode synthesis technique based on experimentally determined modal parameters is presented in this paper. The test structure is a solar array type plate, which is divided into three parts, and four flexible connective parts. In the synthesis, the measured modes are approximated in polynomials to produce rotational degrees of freedom. The results sythesized are in good agreement with the test results obtained from a combined structure.

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

    Bolsman, C.T.; Goosen, J.F.L.; Van 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 wi...

  10. Structure-function studies of the human immunodeficiency virus type 1 matrix protein, p17.

    Cannon, P M; Matthews, S.; Clark, N.; Byles, E D; Iourin, O; Hockley, D J; Kingsman, S M; Kingsman, A J

    1997-01-01

    The human immunodeficiency virus type 1 (HIV-1) matrix protein, p17, plays important roles in both the early and late stages of the viral life cycle. Using our previously determined solution structure of p17, we have undertaken a rational mutagenesis program aimed at mapping structure-function relationships within the molecule. Amino acids hypothesized to be important for p17 function were mutated and examined for effect in an infectious proviral clone of HIV-1. In parallel, we analyzed by nu...

  11. Structure and evolutionary origin of Ca(2+-dependent herring type II antifreeze protein.

    Yang Liu

    Full Text Available In order to survive under extremely cold environments, many organisms produce antifreeze proteins (AFPs. AFPs inhibit the growth of ice crystals and protect organisms from freezing damage. Fish AFPs can be classified into five distinct types based on their structures. Here we report the structure of herring AFP (hAFP, a Ca(2+-dependent fish type II AFP. It exhibits a fold similar to the C-type (Ca(2+-dependent lectins with unique ice-binding features. The 1.7 A crystal structure of hAFP with bound Ca(2+ and site-directed mutagenesis reveal an ice-binding site consisting of Thr96, Thr98 and Ca(2+-coordinating residues Asp94 and Glu99, which initiate hAFP adsorption onto the [10-10] prism plane of the ice lattice. The hAFP-ice interaction is further strengthened by the bound Ca(2+ through the coordination with a water molecule of the ice lattice. This Ca(2+-coordinated ice-binding mechanism is distinct from previously proposed mechanisms for other AFPs. However, phylogenetic analysis suggests that all type II AFPs evolved from the common ancestor and developed different ice-binding modes. We clarify the evolutionary relationship of type II AFPs to sugar-binding lectins.

  12. Type III polyketide synthase repertoire in Zingiberaceae: computational insights into the sequence, structure and evolution.

    Mallika, Vijayanathan; Aiswarya, Girija; Gincy, Paily Thottathil; Remakanthan, Appukuttan; Soniya, Eppurathu Vasudevan

    2016-07-01

    Zingiberaceae or 'ginger family' is the largest family in the order 'Zingiberales' with more than 1300 species in 52 genera, which are mostly distributed throughout Asia, tropical Africa and the native regions of America with their maximum diversity in Southeast Asia. Many of the members are important spice, medicinal or ornamental plants including ginger, turmeric, cardamom and kaempferia. These plants are distinguished for the highly valuable metabolic products, which are synthesised through phenylpropanoid pathway, where type III polyketide synthase is the key enzyme. In our present study, we used sequence, structural and evolutionary approaches to scrutinise the type III polyketide synthase (PKS) repertoire encoded in the Zingiberaceae family. Highly conserved amino acid residues in the sequence alignment and phylogram suggested strong relationships between the type III PKS members of Zingiberaceae. Sequence and structural level investigation of type III PKSs showed a small number of variations in the substrate binding pocket, leading to functional divergence among these PKS members. Molecular evolutionary studies indicate that type III PKSs within Zingiberaceae evolved under strong purifying selection pressure, and positive selections were rarely detected in the family. Structural modelling and protein-small molecule interaction studies on Zingiber officinale PKS 'a representative from Zingiberaceae' suggested that the protein is comparatively stable without much disorder and exhibited wide substrate acceptance. PMID:27138283

  13. Hamiltonian structure for a class of parametric coupled systems of the Korteweg-de Vries type

    We obtain from a lagrangian action describing a class of coupled parametric systems of KdV type its hamiltonian structure. The Poisson algebra arises from second class constraints of the theory and the use of Dirac brackets. The coupled system has relevant applications in physics

  14. Structure cristalline de type alluaudite KNa5Mn3(MoO46

    Chahira Bouzidi

    2015-01-01

    Full Text Available The new phase potassium pentasodium trimanganese hexakis(molybdate, KNa5Mn3Mo6O24, has been synthesized using solid-state methods. The structure is composed of M2O10 (M = Mn, Na dimers and MoO4 tetrahedra (point group symmetry 2 sharing corners and forming layers parallel to (100, which are linked via common corners of another type of MO4 tetrahedra, forming a three-dimensional structure with two types of large channels along [001] in which two types of Na+ cations (one with site symmetry 2, one with -1 and K+ cations (site symmetry 2, half-occupation are located. Mn2+ and the third type of Na+ cations are located at the same site M with occupancies of 0.75 and 0.25, respectively. A comparative structural description is provided between the structure of the title compound and those of the related phases Cu1.35Fe3(PO43 and NaAgFeMn2(PO43.

  15. THE SLACS SURVEY. VIII. THE RELATION BETWEEN ENVIRONMENT AND INTERNAL STRUCTURE OF EARLY-TYPE GALAXIES

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

    2009-01-01

    We study the relation between the internal structure of early-type galaxies and their environment using 70 strong gravitational lenses from the SLACS Survey. The Sloan Digital Sky Survey (SDSS) database is used to determine two measures of overdensity of galaxies around each lens-the projected numbe

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

    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.

  17. Tate twists of Hodge structures arising from abelian varieties of type IV

    Abdulali, Salman

    2012-01-01

    We show that certain abelian varieties A have the property that for every Hodge structure V in the cohomology of A, every effective Tate twist of V occurs in the cohomology of some abelian variety. We deduce the general Hodge conjecture for certain non-simple abelian varieties of type IV.

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

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

  19. Structure and Composition of Protein Bodies from Wild-Type and High-Lysine Barley Endosperm

    Ingversen, J.

    1975-01-01

    Protein bodies were isolated from 13 and 28 day old endosperms of barley mutant 1508 and its wild type, Bomi barley. The fine structure of the isolated protein bodies was determined by electron microscopy, and the proteins present in the preparations characterized by amino-acid analysis and SDS-p...

  20. Pre-adsorbed type-I collagen structure-dependent changes in osteoblastic phenotype

    Type-I collagen is the most abundant extracellular matrix in bones and modulates various functions of osteoblasts. We prepared two different structures of type-I collagen on tissue culture grade polystylene (TCPS) surfaces, one is feltwork structure of filamentous molecules from acid solutions (ACs) and the other is network structure of fibrils from neutral solutions (NCs), to examine effects of the structures on the maturation process of osteoblast-like cells. No significant differences of cell proliferation were observed between TCPS and ACs, but NCs delayed the proliferation. In initial cell attachment, the cells on ACs had tense lamellipodia with sharp tips, while those on NCs had loose lamellipodia. No detectable differences in levels of expressed integrin α2- and α5-subunits were observed between the structures. Although the matrix mineralization in NCs was also delayed in comparison with TCPS and ACs, fully mineralized levels in NCs were the same as those of TCPS and ACs. In addition, although we examined the effects of densities of pre-adsorbed collagen molecules on osteoblast maturation, the effects were less serious than those of the structures. This study suggests that the structures of collagen affect proliferation and mineralization of osteoblast-like cells

  1. Vector-type four-quark interaction and its impact on QCD phase structure

    Effects of the vector-type four-quark interaction on QCD phase structure are investigated in the imaginary chemical potential (μ) region, by using the Polyakov-loop extended Nambu-Jona-Lasinio model with the extended Z3 symmetry. We clarify analytically the Roberge-Weiss periodicity and symmetry properties of various quantities under the existence of a vector-type four-quark interaction. In the imaginary μ region, the chiral condensate and the quark-number density are sensitive to the strength of the interaction. Based on this result, we propose a possibility to determine the strength of the vector-type interaction, which largely affects QCD phase structure in the real μ region, by comparing the results of lattice simulations and effective model calculations in the imaginary μ region.

  2. Perturbation method of analyzing mode localization of asymmetrical plate-type structure in incompressible flows

    The dynamical characteristics of a simple two-span parallel flat plate-type model vibrating in incompressible water are studied here. The assumption mode method is used to form the motion equation of the structure. By using a second order perturbation method, the great emphasis is focused on the influences of the asymmetrical parameter of the structure, the deviation of length and stiffness of the torsional spring on the degrees of mode localization of the structure. The results show that the second method can be applied to predict the dynamical characteristics of the structure accurately. The influences of the coupling effect of the fluid on the phenomena of the two piece beams' mode localization are different. The asymmetrical parameter of length is the main factor that leads to the behaviors of mode localization of the structure. The deviation of stiffness of the torsional spring, too, has significant influences on the phenomena of mode localization

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

    Igor Tomičić

    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.

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

    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.

  5. Structural characterization of outer membrane components of the type IV pili system in pathogenic Neisseria.

    Samta Jain

    Full Text Available Structures of the type IV pili secretin complexes from Neisseria gonorrhoeae and Neisseria meningitidis, embedded in outer membranes were investigated by transmission electron microscopy. Single particle averaging revealed additional domains not observed previously. Secretin complexes of N. gonorrhoeae showed a double ring structure with a 14-15-fold symmetry in the central ring, and a 14-fold symmetry of the peripheral ring with 7 spikes protruding. In secretin complexes of N. meningitidis, the spikes were absent and the peripheral ring was partly or completely lacking. When present, it had a 19-fold symmetry. The structures of the complexes in several pil mutants were determined. Structures obtained from the pilC1/C2 adhesin and the pilW minor pilin deletion strains were similar to wild-type, whereas deletion of the homologue of N. meningitidis PilW resulted in the absence of secretin structures. Remarkably, the pilE pilin subunit and pilP lipoprotein deletion mutants showed a change in the symmetry of the peripheral ring from 14 to 19 and loss of spikes. The pilF ATPase mutant also lost the spikes, but maintained 14-fold symmetry. These results show that secretin complexes contain previously unidentified large and flexible extra domains with a probable role in stabilization or assembly of type IV pili.

  6. Catalytic oxidation of methanol on Pt/X (X = CaTP, NaTP electrodes in sulfuric acid solution

    Said Benmokhtar

    2013-10-01

    Full Text Available In this paper, we report the synthesis and characterization of electrodes based on NASICON type phosphates. The study of the electrochemical oxidation of methanol at ambient temperature on electrodes based on NASICON type Ca0,5Ti2(PO43 (CaTP and Na5Ti(PO43 (NaTP compared to that of the platinum electrode model has been conducted by cyclic voltammetry in acidic medium. The results showed a significant increase of current density on the electro oxidation of methanol on the material developed based NASICON structure CaTP, cons deactivation of the electro oxidation is observed the closed structure type NaTP.

  7. Investigation into possible geometrical configurations for scissor-type deployable structures using expandable bars

    Lee, Daniel Sang-Hoon; Jia, Wenwen; Cai, Jianguo;

    2015-01-01

    The current paper describes a spin-off investigation from the initially published international research project [1] [2] , which is looking into the design and development of single-meridian grid deployable structure. As a part of the collaborative international project between South Korea (Proje...... geometrical configurations of the structure in 2D space Investigation into possible geometrical configurations for scissor-type deployable structures using expandable bars....... of the expandable bars for creation of dynamic three-dimensional (3D) space using scissor-type deployable system. The research starts with the detail design and prototype construction of the expandable bars in collaboration between the Royal Danish Academy, School of Architecture in Denmark and School of Civil...

  8. Hydrogen position, hydrogen bonding and hydroxide dynamics in the Cd(OH)Cl structure type

    Complete text of publication follows. The crystal structure of Cd(OH)Cl is already known since the single-crystal and powder diffraction investigations by Hoard and Grenko (1). It crystallizes in its own structure type which is intimately related to the layer structures of cadmium hydroxide and cadmium chloride. Although the isotypic structures of Ca(OH)Cl (2) and Sr(OH)Cl (3) have been examined, the hydrogen position of this structure type, however, is not yet completely clear. We performed single crystal diffraction of Cd(OH)Cl on a modern κ-CCD diffractometer, TOF neutron powder diffraction experiments with an annular cylindrical sample of Cd(OD)Cl, temperature dependent 2H-NMR-spectroscopy and quantum mechanical calculations to reinvestigate the crystal structure with full information about H-position, H-bonding and hydroxide dynamics. The results show that the hydrogen position is near a three-fold axis, that only small angle liberations occur and the amount of hydrogen bonding can be neglected. (author)

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

    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.

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

    Kodesová, Radka; Vignozzi, Nadia; Rohosková, Marcela; Hájková, Tereza; Kocárek, Martin; Pagliai, Marcello; Kozák, Josef; Simůnek, Jirka

    2009-02-16

    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

  11. The structure of the R^8 term in type IIB string theory

    Basu, Anirban

    2013-01-01

    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 (t_8 t_8 R^4)^2, which we call the R^8 interaction. It lies in the same supermultiplet as the G^8 R^4 interaction. Using the KLT relation, we analyse the structure of the tree level eight graviton scattering amplitude in the type IIB theory, which leads to the R^8 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 R^8 interaction receives non-analytic contributions in the string coupling at one and two loops. Apart from receiving perturbative contributions, we show that the R^8 interaction receives a non-vanishing contribution in the one D-instanton-anti-instanton background at lea...

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

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

    2009-05-01

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

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

    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)

  14. In-vineyard population structure of 'Candidatus Phytoplasma solani' using multilocus sequence typing analysis.

    Murolo, Sergio; Romanazzi, Gianfranco

    2015-04-01

    'Candidatus Phytoplasma solani' is a phytoplasma of the stolbur group (16SrXII subgroup A) that is associated with 'Bois noir' and causes heavy damage to the quality and quantity of grapevine yields in several European countries, and particularly in the Mediterranean area. Analysis of 'Ca. P. solani' genetic diversity was carried out for strains infecting a cv. 'Chardonnay' vineyard, through multilocus sequence typing analysis for the vmp1, stamp and secY genes. Several types per gene were detected: seven out of 20 types for vmp1, six out of 17 for stamp, and four out of 16 for secY. High correlations were seen among the vmp1, stamp and secY typing with the tuf typing. However, no correlations were seen among the tuf and vmp1 types and the Bois noir severity in the surveyed grapevines. Grouping the 'Ca. P. solani' sequences on the basis of their origins (i.e., study vineyard, Italian regions, Euro-Mediterranean countries), dN/dS ratio analysis revealed overall positive selection for stamp (3.99, P=0.019) and vmp1 (2.28, P=0.001). For secY, the dN/dS ratio was 1.02 (P=0.841), showing neutral selection across this gene. Using analysis of the nucleotide sequencing by a Bayesian approach, we determined the population structure of 'Ca. P. solani', which appears to be structured in 3, 5 and 6 subpopulations, according to the secY, stamp and vmp1 genes, respectively. The high genetic diversity of 'Ca. P. solani' from a single vineyard reflects the population structure across wider geographical scales. This information is useful to trace inoculum source and movement of pathogen strains at the local level and over long distances. PMID:25660034

  15. Solution structure of monomeric BsaL, the type III secretion needle protein of Burkholderia pseudomallei.

    Zhang, Lingling; Wang, Yu; Picking, Wendy L; Picking, William D; De Guzman, Roberto N

    2006-06-01

    Many gram-negative bacteria that are important human pathogens possess type III secretion systems as part of their required virulence factor repertoire. During the establishment of infection, these pathogens coordinately assemble greater than 20 different proteins into a macromolecular structure that spans the bacterial inner and outer membranes and, in many respects, resembles and functions like a syringe. This type III secretion apparatus (TTSA) is used to inject proteins into a host cell's membrane and cytoplasm to subvert normal cellular processes. The external portion of the TTSA is a needle that is composed of a single type of protein that is polymerized in a helical fashion to form an elongated tube with a central channel of 2-3 nm in diameter. TTSA needle proteins from a variety of bacterial pathogens share sequence conservation; however, no atomic structure for any TTSA needle protein is yet available. Here, we report the structure of a TTSA needle protein called BsaL from Burkholderia pseudomallei determined by nuclear magnetic resonance (NMR) spectroscopy. The central part of the protein assumes a helix-turn-helix core domain with two well-defined alpha-helices that are joined by an ordered, four-residue linker. This forms a two-helix bundle that is stabilized by interhelix hydrophobic contacts. Residues that flank this presumably exposed core region are not completely disordered, but adopt a partial helical conformation. The atomic structure of BsaL and its sequence homology with other TTSA needle proteins suggest potentially unique structural dynamics that could be linked with a universal mechanism for control of type III secretion in diverse gram-negative bacterial pathogens. PMID:16631790

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

    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

  17. Structure function relationship in P-type ATPases : a biophysical approach

    Apell, Hans-Jürgen

    2003-01-01

    P-type ATPases are a large family of membrane proteins that perform active ion transport across biological membranes. In these proteins the energy-providing ATP hydrolysis is coupled to ion-transport that builds up or maintains the electrochemical potential gradients of one or two ion species across the membrane. P-type ATPases are found in virtually all eukaryotic cells and also in bacteria, and they are transporters of a broad variety of ions. So far, a crystal structure with atomic resolut...

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

    Mehmet TERZİ

    2006-03-01

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

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

    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.

  20. Development of new type passive autocatalytic recombiner. Part 2. Proposal of conceptual structure

    A new type passive autocatalytic recombiner to mitigate released hydrogen gas at the accident of nuclear power plants and related facilities has been developed. In order to realize easy and anywhere installation, this new recombiner has advanced automotive catalysts with features such as light and small, high durability, and high performance. Downsizing and light-weighting of recombiner has been conducted with thermal hydraulic and structural analysis incorporating an automotive catalyst model and its characterization results obtained through experiments. Thermal hydraulic and structural analysis show PAR concept proposed is feasible for hydrogen mitigation in nuclear power plants and related facilities. (author)

  1. New transition metal oxide fluorides with ReO3-type structure

    The new niobium oxide fluorides MNbO2F4 [M = (Cr, Fe)], CrNb2O4F5, and Fe2Nb3O6F9 were prepared by treatment of chromium or iron nitrate with Nb-containing hydrofluoric acid solutions. Crystal structures were investigated by means of X-ray powder diffraction. All new compounds can be structurally refined in the cubic ReO3-type. The iron niobium oxide fluorides are reddish orange, and chromium containing phases exhibit a light green color. The niobium atoms are in the highest formal oxidation state.

  2. Structure of the Myotonic Dystrophy Type 2 RNA and Designed Small Molecules That Reduce Toxicity

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

    2013-01-01

    Myotonic dystrophy type 2 (DM2) is an untreatable neuromuscular disorder caused by a r(CCUG) expansion (r(CCUG)exp) that folds into an extended hairpin with periodically repeating 2×2 nucleotide internal loops (5’CCUG/3’GUCC). We designed multivalent compounds that improve DM2-associated defects using information about RNA-small molecule interactions. We also report the first crystal structure of r(CCUG)exp refined to 2.35 Å. Structural analysis of the three 5’CCUG/3’GUCC repeat internal loop...

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

    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 transmembrane helix kinks at a double-glycine motif displaying an amphipathic helix that lines a...

  4. Family Structure Types and Adequate Utilization of Antenatal Care in Kenya.

    Owili, Patrick Opiyo; Muga, Miriam Adoyo; Chou, Yiing-Jenq; Hsu, Yi-Hsin Elsa; Huang, Nicole; Chien, Li-Yin

    2016-01-01

    Features of the health care delivery system may not be the only expounding factors of adequate utilization of antenatal care among women. Other social factors such as the family structure and its environment contribute toward pregnant women's utilization of antenatal care. An understanding of how women in different family structure types and social groups use basic maternal health services is important toward developing and implementing maternal health care policy in the post-Millennium Development Goal era, especially in the sub-Saharan Africa where maternal mortality still remains high. PMID:27214674

  5. Determination of height of transfer unit at hydrogen isotopic distillation on B7 type structured packing

    Due to the low pressure drop which that the structured packing introduces it is often used in the case of distillations under vacuum and of the mixture separation when the desired component is present in very low concentration, for example the water, hydrogen and oxygen isotopic distillation. The paper presents a model for the determination of height of transfer unit at hydrogen isotopic distillation plant with structured B7 type packing. The values of HTU calculated with the analogy model between the heat, momentum and mass transfer are compared with the experimental data. (authors)

  6. Height of transfer unit determination at hydrogen isotopic distillation on structured packing, B7 type

    Due to the low pressure drop that it introduces, the structured packing is often used in the case of distillations under vacuum and of the mixture separation when the desired component is founded in very low concentration, for example the water, hydrogen and oxygen isotopic distillation. The paper presents a model for the determination of height of transfer unit at hydrogen isotopic distillation plant with structured B7 type packing. The values of the height of a transfer unit (HTU) calculated with the analogy model between the heat, momentum and mass transfer are compared with the experimental data

  7. Height of transfer unit determination at hydrogen isotopic distillation on B7 type structured packing

    Due to the low pressure drop that it introduces, the structured packing is often used in the case of distillation under vacuum and of the mixture separation when the desired component is found in very low concentration, for example the water, hydrogen and oxygen isotopic distillation. The paper presents a model for the determination of height of transfer unit at hydrogen isotopic distillation plant with structured B7 type packing. The values of HTU calculated with the analogy model between the heat, momentum and mass transfer are compared with the experimental data. (authors)

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

    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.

  9. A Structural Approach to Assessing Innovation: Construct Development of Innovation Locus, Type, and Characteristics

    Hubert Gatignon; Michael L. Tushman; Wendy Smith; Philip Anderson

    2002-01-01

    We take a structural approach to assessing innovation. We develop a comprehensive set of measures to assess an innovation's locus, type, and characteristics. We find that the concepts of competence destroying and competence enhancing are composed of two distinct constructs that, although correlated, separately characterize an innovation: new competence acquisition and competence enhancement/destruction. We develop scales to measure these constructs and show that new competence acquisition and...

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

    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 ...

  11. A Crack Identification Method For Beam Type Structures Subject To Moving Vehicle Using Particle Swarm Optimization

    GÖKDAĞ, Hakan

    2013-01-01

    In this work a crack identification method for beam type structures under moving vehicle is proposed. The basic of the method is to formulate damage detection as an inverse problem, and solve for damage locations and extents. To this end, an objective function is defined based on the difference of damaged beam dynamic response and the response calculated by the mathematical model of the beam. The optimization problem is solved through a popular evolutionary algorithm, i.e. the particle swarm ...

  12. Godunov type method on non-structured meshes for three-dimensional moving boundary problems

    Nkonga, Boniface; Guillard, Hervé

    1993-01-01

    This paper presents a numerical method for the computation of compressible flows in domains whose boundaries move in a well defined predictable manner. The method uses the space-time formulations by Godunov while the discretization is conducted on non-structured tetrahedral meshes, using Roe's approximate Riemann solver, an implicit time stepping and a MUSCL-type interpolation. The computation of the geometrical parameters required to take into account the movement of the boundaries is descri...

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

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

    2010-01-01

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

  14. Surface states and bulk electronic structure in the candidate type-II Weyl semimetal WTe2

    Bruno, F. Y.; Tamai, A.; Wu, Q. S.; Cucchi, I.; Barreteau, C.; A. de la Torre; Walker, S. McKeown; Riccò, S; Wang, Z.; Kim, T K; Hoesch, M.; Shi, M. (Mimi); Plumb, N. C.; Giannini, E; Soluyanov, A. A.

    2016-01-01

    We report angle-resolved photoemission experiments identifying an arc-like surface state connecting the bulk electron and hole pockets of the candidate type-II Weyl semimetal WTe2. This surface state can be isolated clearly on one of two distinct surface terminations observed experimentally, which we associate with the in-equivalent top and bottom surfaces of the non-centrosymmetric crystal structure. We further use the identification of the two different surfaces to clarify the number of bul...

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

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

  16. How similar is the stellar structure of low-mass late-type galaxies to that of early-type dwarfs?

    Janz, Joachim; Laine, Jarkko; Salo, Heikki; Lisker, Thorsten

    2016-01-01

    We analyse structural decompositions of 500 late-type galaxies (Hubble $T$-type $\\ge 6$) from the Spitzer Survey of Stellar Structure in Galaxies (S$^4$G), spanning a stellar mass range of about $10^7$ to a few times $10^{10}$ M$_\\odot$. Their decomposition parameters are compared with those of the early-type dwarfs in the Virgo cluster from Janz et al. They have morphological similarities, including the fact that the fraction of simple one-component galaxies in both samples increases towards lower galaxy masses. We find that in the late-type two-component galaxies both the inner and outer structures are by a factor of two larger than those in the early-type dwarfs, for the same stellar mass of the component. While dividing the late-type galaxies to low and high density environmental bins, it is noticeable that both the inner and outer components of late types in the high local galaxy density bin are smaller, and lie closer in size to those of the early-type dwarfs. This suggests that, although structural dif...

  17. Community structure and regeneration types of Betula dahurica forest in Badaling forest center of Beijing

    Zhang Yong; Zheng Zhi-hua; Zhang Zhi-xiang

    2007-01-01

    Using plant community analysis methods, we analyzed the floristic characteristics, species composition, community structure, population structure, and spatial distribution patterns of a Betula dahurica forest on the "1238" mountain of Badaling in Beijing, China. The results show that: 1) There are 33 plant species in the B. dahurica community, including 18 woody plant species. The B. dahurica forest is a monodominant community with 75.9% dominance. 2) Based on diameter at breast height (DBH)size class distribution, the population structure of B. dahurica and Acer mono-two heliophyllous and pioneer tree species is cascade-type, with both in an increasing stage. The population structure of Tilia mandshurica and T. mongolica, two shade-tolerant tree species, is inverse-J type, and they have more young seedling individuals and regenerate more stably. They are associated species of the pioneer tree species. The population structure of Quercus mongolica, as the associated species of climax species in the community, is sporadic, and its regeneration is fluctuating and random. Fraxinus rhynchophylla is a shade-tolerant tree species which has a unibar population structure and climax characteristics of pioneer tree species. The relative frequency of young seedlings reached 0.4.3) The dominant species B. dahurica is still in an increasing stage, and the regeneration of other species is steady or partly influences the community, putting the community in the pioneer species stage. From the population structure and distribution frequency ofF. rhynchophylla, the B. dahurica forest will approach to a climax state in the future.

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

    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 β-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. Microcrystalline-Silicon-Oxide-Based N-Type Reflector Structure in Micromorph Tandem Solar Cells

    Chiung-Nan Li

    2012-01-01

    Full Text Available N-type microcrystalline silicon oxide thin films (n-c-SiO:H have been deposited by VHF-PECVD (40 MHz with reactant gas mixtures of CO2/SiH4 and H2. N-c-SiO thin films exhibiting low refractive index value (n600nm∼2, and medium/high conductivity (≧10−9 S/cm are suitable to be used as an “n-type reflector” in micromorph tandem solar cells. Transmission electron microscopy (TEM results show that microstructures of n-c-SiO:H thin films contain nanocrystalline Si particles, which are randomly embedded in the a-SiO matrix. This specific microstructure provides n-c-SiO:H thin films excellent optoelectronic properties; therefore, n-c-SiO:H thin films are appropriate candidates for “n-type reflector” structures in Si tandem solar cells.

  20. Damage identification in beam type structures based on statistical moment using a two step method

    Wang, Dansheng; Xiang, Wei; Zhu, Hongping

    2014-02-01

    This paper defines a novel damage index-strain statistical moment, and formulates the fourth strain statistical moment (FSSM) of beam-type structures under white noise excitation. Based on this newly defined strain statistical moment index and the least square optimization algorithm, a two-step damage identification method is proposed. This two-step method is operated like this: first use the difference curves of FSSMs before and after damage to locate damage elements; then for those identified damage elements, employ the model updating method based on the least square algorithm to assess their damage severity. Numerical studies on a simply supported beam and a two-span continuous beam are performed and the study results show that the newly defined index is effective to locate damages, even when the noise intensity is as high as 15 percent. Integrating with the least square-based model updating technique, the damage severities of beam-type structures can also be determined quantitatively. In this way, the proposed two-step method is verified and found to be capable of identifying damage positions and severities of beam-type structures and insensitive to measurement noise.

  1. Decomposition of Spinel-Type Nickel Chromium Indium Sulfides—X-Ray Powder Structure Determination

    Lutz, H. D.; Kringe, Ch.; Mohn, K.; Stingl, Th.

    1998-03-01

    The phase diagram of the quaternary system NiCr 2S 4-NiIn 2S 4-Cr 2S 3-In 2S 3has been studied at 873 and 1223 K by X-ray powder structure determination of quenched samples. At high temperatures, spinel-type Ni y(Cr 2-2 xIn 2 x) 1- yS 3-2 ysolid solutions are formed in a large range of composition ( y: 0-0.5, x: 0.3-1). At temperatures below 1183 K, these solid solutions decompose to Cr-rich and In-rich spinel-type sulfides, whereby nickel is enriched in the Cr-rich compounds. The decomposition of the spinel-type sulfides is greatly retarded, even at temperatures about 900 K, due to both thermodynamic and kinetic reasons. The cation distribution established corresponds to a site preference as Cr 3+>Ni 2+>In 3+at the octahedral 16d site and □ (vacancies)>In 3+>Ni 2+at the tetrahedral 8a site of the spinel structure. The metal-sulfur distances of the solid solutions refined are compared with those calculated from characteristic metal-sulfur distances in close-packed structures, taking into account the site occupation established. For the respective indium-sulfur distances, the following improved values are recommended: In tet-S=247.1 pm; In oct-S=260.6 pm.

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

    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. Excitonic transitions in highly efficient (GaIn)As/Ga(AsSb) type-II quantum-well structures

    The excitonic transitions of the type-II (GaIn)As/Ga(AsSb) gain medium of a “W”-laser structure are characterized experimentally by modulation spectroscopy and analyzed using microscopic quantum theory. On the basis of the very good agreement between the measured and calculated photoreflectivity, the type-I or type-II character of the observable excitonic transitions is identified. Whereas the energetically lowest three transitions exhibit type-II character, the subsequent energetically higher transitions possess type-I character with much stronger dipole moments. Despite the type-II character, the quantum-well structure exhibits a bright luminescence

  4. Structural and Morphometric Comparison of Lower Incisors in PACAP-Deficient and Wild-Type Mice.

    Sandor, B; Fintor, K; Reglodi, D; Fulop, D B; Helyes, Z; Szanto, I; Nagy, P; Hashimoto, H; Tamas, A

    2016-06-01

    Pituitary adenylate cyclase activating polypeptide (PACAP) is a neuropeptide with widespread distribution. PACAP plays an important role in the development of the nervous system, it has a trophic and protective effect, and it is also implicated in the regulation of various physiological functions. Teeth are originated from the mesenchyme of the neural crest and the ectoderm of the first branchial arch, suggesting similarities with the development of the nervous system. Earlier PACAP-immunoreactive fibers have been found in the odontoblastic and subodontoblastic layers of the dental pulp. Our previous examinations have shown that PACAP deficiency causes alterations in the morphology and structure of the developing molars of 7-day-old mice. In our present study, morphometric and structural comparison was performed on the incisors of 1-year-old wild-type and PACAP-deficient mice. Hard tissue density measurements and morphometric comparison were carried out on the mandibles and the lower incisors with micro-CT. For structural examination, Raman microscopy was applied on frontal thin sections of the mandible. With micro-CT morphometrical measurements, the size of the incisors and the relative volume of the pulp to dentin were significantly smaller in the PACAP-deficient group compared to the wild-type animals. The density of calcium hydroxyapatite in the dentin was reduced in the PACAP-deficient mice. No structural differences could be observed in the enamel with Raman microscopy. Significant differences were found in the dentin of PACAP-deficient mice with Raman microscopy, where increased carbonate/phosphate ratio indicates higher intracrystalline disordering. The evaluation of amide III bands in the dentin revealed higher structural diversity in wild-type mice. Based upon our present and previous results, it is obvious that PACAP plays an important role in tooth development with the regulation of morphogenesis, dentin, and enamel mineralization. Further studies are

  5. Molecular dynamics studies on the structural stability of wild-type dog prion protein.

    Zhang, Jiapu; Liu, David D W

    2011-06-01

    Prion diseases such as Creutzfeldt-Jakob disease, variant Creutzfeldt-Jakob diseases, Gerstmann-Sträussler-Scheinker syndrome, Fatal Familial Insomnia, Kuru in humans, scrapie in sheep, bovine spongiform encephalopathy (or 'mad-cow' disease) and chronic wasting disease in cattle are invariably fatal and highly infectious neurodegenerative diseases affecting humans and animals. However, by now there have not been some effective therapeutic approaches to treat all these prion diseases. In 2008, canine mammals including dogs (canis familials) were the first time academically reported to be resistant to prion diseases (Vaccine 26: 2601-2614 (2008)). Thus, it is very worth studying the molecular structures of dog prion protein to obtain insights into the immunity of dogs to prion diseases. This paper studies the molecular structural dynamics of wild-type dog prion protein. The comparison analyses with rabbit prion protein show that the dog prion protein has stable molecular structures whether under neutral or low pH environments. We also find that the salt bridges such as D177-R163 contribute to the structural stability of wild-type rabbit prion protein under neutral pH environment. PMID:21469747

  6. Rh3B2-x, new structure type of binary borides with triclinic symmetry

    New binary compound Rh3B2-x, x=0.167 crystallizing with its own structure type has been observed from the as cast alloys. The compound has a limited thermal stability range: it was found to decompose after annealing at 800oC for 20 days. The crystal structure was investigated by X-ray diffraction from two single crystals using different techniques: CAD-4 automatic diffractometer, a=5.470(2), b=6.816(3), c=9.068(4), α=110.74(3), β=94.81(3), γ=90.44(2), 107 refined parameters, R1=0.0418, wR2=0.1087 for 1223 reflections with I>2σ(Io), and BRUKER SMART AXS, a=5.483(4), b=6.818(6), c=9.072 (7), a=110.78(1), b=94.73(1), g=90.46(1), 107 refined parameters, R1=0.0401, wR2=0.0959 for 943 reflections with I>2σ(Io). The Rh3B2-x, structure (space group P1-bar , Pearson symbol aP30-1) is the first representative of structures with triclinic symmetry among binary borides and contains three different types of boron-boron aggregation: isolated boron atoms, B-B pairs and B6 chain fragments

  7. Mushroom-type structures with the wires connected through diodes: Theory and applications

    Forouzmand, Ali; Kaipa, Chandra S. R.; Yakovlev, Alexander B.

    2016-07-01

    In this paper, we establish a general formalism to quantify the interaction of electromagnetic waves with mushroom-type structures (high impedance surface and bi-layer) with diodes inserted along the direction of the wires. The analysis is carried out using the nonlocal homogenization model for the mushroom structure with the generalized additional boundary conditions at the connection of the wires to diodes. We calculate numerically the magnitude and phase of the reflected/transmitted fields in the presence of an ideal and realistic PIN diodes. It is observed that the reflection/transmission characteristics of the mushroom-type structures can be controlled by tuning the working states of the integrated PIN diodes. We realize a structure with a multi-diode switch to minimize the undesired transmission for a particular incident angle. In addition, a dual-band subwavelength imaging lens is designed based on the resonant amplification of evanescent waves, wherein the operating frequency can be tuned by changing the states of the PIN diodes. The analytical results are verified with the full-wave electromagnetic solver CST Microwave Studio, showing a good agreement.

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

    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

  9. Superconductivity in layered ZrP2-x Se x with PbFCl-type structure

    Ishida, Shigeyuki; Fujihisa, Hiroshi; Hase, Izumi; Yanagi, Yousuke; Kawashima, Kenji; Oka, Kunihiko; Gotoh, Yoshito; Yoshida, Yoshiyuki; Iyo, Akira; Eisaki, Hiroshi; Kito, Hijiri

    2016-05-01

    We performed a systematic study of the crystal structure, physical properties, and electronic structure of PbFCl-type ZrP2-x Se x (0.3 ≤ x ≤ 0.9). We successfully synthesized single-phase polycrystalline samples for the Se substitution range of 0.4 ≤ x ≤ 0.8. The crystal structure of the compound is characterized by the alternate stacking of a two-dimensional P square net and a Zr-(P1-x Se x ) network. ZrP2-x Se x exhibits a dome-like superconductivity phase diagram and has a maximum superconducting transition temperature (T c) of 6.3 K for x ≈ 0.6. Resistivity and Hall measurements indicated that electron-phonon scattering plays a dominant role and that electron-type carriers dominate charge transport. Specific heat measurements confirmed that ZrP2-x Se x exhibits bulk superconductivity. Further, the value of the specific heat jump at T c (ΔC/γT c ≈ 1.35) is in keeping with the BCS weak-coupling model. These facts suggest a rather conventional pairing mechanism in ZrP2-x Se x . The x dependence of T c can be explained on the basis of the density of states (DOS) for x ≤ 0.7, whereas the decrease in T c with an increase in the DOS for x = 0.8 needs further investigation. One possible reason for the suppression of superconductivity is that the PbFCl-type structure becomes unstable for x ≥ 0.8. The results of electronic structure calculations agree reasonably well with those of the experimental observations, suggesting that the Zrd band plays a primary role in determining the physical properties. Further, the calculations predict a significant change in the Fermi-surface topology for x ≥ 0.8 this is a probable reason for the decrease in T c as well as the instability of the PbFCl-type structure.

  10. Synthesis and crystal structures of C24-epimeric 20(R)-ocotillol-type saponins.

    Xu, Yang Rong; Yang, Jing Jing; Liu, Juan; Hou, Gui Ge; Meng, Qing Guo

    2016-06-01

    Ocotillol-type saponins have a wide spectrum of biological activities. Previous studies indicated that the configuration at the C24 position may be responsible for their stereoselectivity in pharmacological action and pharmacokinetics. Natural ocotillol-type saponins share a 20(S)-form but it has been found that the 20(R)-stereoisomers have different pharmacological effects. The semisynthesis of 20(R)-ocotillol-type saponins has not been reported and it is therefore worthwhile clarifying their crystal structures. Two C24 epimeric 20(R)-ocotillol-type saponins, namely (20R,24S)-20,24-epoxydammarane-3β,12β,25-triol, C30H52O4, (III), and (20R,24R)-20,24-epoxydammarane-3β,12β,25-triol monohydrate, C30H52O4·H2O, (IV), were synthesized, and their structures were elucidated by spectral studies and finally confirmed by single-crystal X-ray diffraction. The (Me)C-O-C-C(OH) torsion angle of (III) is 146.41 (14)°, whereas the corresponding torsion angle of (IV) is -146.4 (7)°, indicating a different conformation at the C24 position. The crystal stacking in (III) generates an R4(4)(8) motif, through which the molecules are linked into a one-dimensional double chain. The chains are linked via nonclassical C-H...O hydrogen bonds into a two-dimensional network, and further stacked into a three-dimensional structure. In contrast to (III), epimer (IV) crystallizes as a hydrate, in which the water molecules act as hydrogen-bond donors linking one-dimensional chains into a two-dimensional network through intermolecular O-H...O hydrogen bonds. The hydrogen-bonded chains extend helically along the crystallographic a axis and generate a C4(4)(8) motif. PMID:27256698

  11. Structure and age-dependent development of the turkey liver: a comparative study of a highly selected meat-type and a wild-type turkey line.

    Hünigen, Hana; Mainzer, Kathleen; Hirschberg, Ruth M; Custodis, Pia; Gemeinhardt, Ole; Al Masri, Salah; Richardson, Kenneth C; Hafez, Hafez Mohamed; Plendl, Johanna

    2016-04-01

    In this study the macroscopic and microscopic structure of the liver of a fast growing, meat-type turkey line (British United turkeys BUT Big 6, n=25) and a wild-type turkey line (Wild Canadian turkey, n=48) were compared at the age of 4, 8, 12, 16, and 20 wk. Because the growth plates of long bones were still detectable in the 20-week-old wild-type turkeys, indicating immaturity, a group of 8 wild-type turkeys at the age of 24 wk was included in the original scope of the study. Over the term of the study, the body and liver weights of birds from the meat-type turkey line increased at a faster rate than those of the wild-type turkey line. However, the relative liver weight of the meat-type turkeys declined (from 2.7 to 0.9%) to a greater extent than that of the wild-type turkeys (from 2.8 to 1.9%), suggesting a mismatch in development between muscle weights and liver weights of the meat-type turkeys. Signs of high levels of fat storage in the liver were detected in both lines but were greater in the wild-type turkey line, suggesting a better feed conversion by the extreme-genotype birds i.e., meat-type birds. For the first time, this study presents morphologic data on the structure and arrangement of the lymphatic tissue within the healthy turkey liver, describing two different types of lymphatic aggregations within the liver parenchyma, i.e., aggregations with and without fibrous capsules. Despite differences during development, both adult meat-type and adult wild-type turkeys had similar numbers of lymphatic aggregations. PMID:26908884

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

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

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

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

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

    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.

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

    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.

  16. Structure of the Type IVa Major Pilin from the Electrically Conductive Bacterial Nanowires of Geobacter sulfurreducens

    Reardon, Patrick N.; Mueller, Karl T.

    2013-10-11

    Several species of bacteria are capable of reducing insoluble metal oxides as well as other extracellular electron acceptors. These bacteria play a critical role in the cycling of minerals in subsurface environments, sediments, and groundwater. In some species of bacteria, such as Geobacter sulfurreducens, the transport of electrons is facilitated by filamentous fibers that are referred to as bacterial nanowires. These nanowires belong to the type IVa family of pilin proteins and are mainly comprised of one subunit protein, PilA. Here, we report the high resolution solution nuclear magnetic resonance (NMR) structure of the PilA protein from G. sulfurreducens determined in detergent micelles. The protein is over 85% α-helical and exhibits similar architecture to the N-terminal regions of other non-conductive type IVa pilins. The detergent micelle interacts with the first 21 amino acids of the protein, indicating that this region likely associates with the bacterial inner membrane prior to fiber formation. A model of the G. sulfurreducens pilus fiber is proposed based on docking of this structure into the fiber model of the type IVa pilin from Neisseria gonorrhoeae. This model provides insight into the organization of aromatic amino acids that are important for electrical conduction.

  17. The spectra of type IIB flux compactifications at large complex structure

    Brodie, Callum; Marsh, M. C. David

    2016-01-01

    We compute the spectra of the Hessian matrix, H, and the matrix 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 H and 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 is strongly linearly correlated with the value of the superpotential over almost the entire moduli space, with particularly strong correlations arising for g s string theory landscape.

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

    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...

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

    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.

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

    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

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

    Azar Shahpiri; Birte Svensson; Christine Finnie

    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 dependenl 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 knowl-edge of the barley system including recent data on function,regulation,interactions,and structure.Directions for future research are discussed.

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

    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 β-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

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

    Labudde, D.; Leitner, D.; Krueger, M.; Oschkinat, H. [Forschungsinstitut fuer Molekulare Pharmakologie (Germany)], E-mail: oschkinat@fmp-berlin.de

    2003-01-15

    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 {alpha}-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 {alpha}-helix, {beta}-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.

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

    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 α-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 α-helix, β-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

  5. Dynamical structure of solar radio burst type III as evidence of energy of solar flares

    Hamidi, Zety Sharizat Binti

    2013-11-01

    Observations of low frequency solar type III radio bursts associated with the ejection of plasma oscillations localized disturbance is due to excitation atoms in the plasma frequency incoherent radiations play a dominant role at the meter and decimeter wavelengths. Here, we report the results of the dynamical structure of solar flare type III that occurred on 9th March 2012 at National Space Centre, Sg Lang, Selangor, Malaysia by using the CALLISTO system. These bursts are associated with solar flare type M6 which suddenly ejected in the active region AR 1429 starting at 03:32 UT and ending at 05:00 UT with the peak at 04:12 UT. The observation showed an initial strong burst occurred due to strong signal at the beginning of the phase. We also found that both solar burst and flares tend to be a numerous on the same day and probability of chance coincidence is high. It is clearly seen that an impulsive lace burst was detected at 4:24 UT and it is more plausible that the energies are confined to the top of the loop when we compared with X-ray results. Associated with this event was type II with velocities 1285 km/s and type IV radio sweeps along with a full halo Coronal Mass Ejections (CMEs) first seen in SOHO/LASCO C2 imagery at 09/0426 Z. We concluded that the significance of study solar burst type III lies in the fact that the emission at decimetric wavelength comes from the role of magnetic field in active region that may provide the key to the energy release mechanism in a flare.

  6. Mechanical adaptability of the Bouligand-type structure in natural dermal armour.

    Zimmermann, Elizabeth A; Gludovatz, Bernd; Schaible, Eric; Dave, Neil K N; Yang, Wen; Meyers, Marc A; Ritchie, Robert O

    2013-01-01

    Arapaima gigas, a fresh water fish found in the Amazon Basin, resist predation by piranhas through the strength and toughness of their scales, which act as natural dermal armour. Arapaima scales consist of a hard, mineralized outer shell surrounding a more ductile core. This core region is composed of aligned mineralized collagen fibrils arranged in distinct lamellae. Here we show how the Bouligand-type (twisted plywood) arrangement of collagen fibril lamellae has a key role in developing their unique protective properties, by using in situ synchrotron small-angle X-ray scattering during mechanical tensile tests to observe deformation mechanisms in the fibrils. Specifically, the Bouligand-type structure allows the lamellae to reorient in response to the loading environment; remarkably, most lamellae reorient towards the tensile axis and deform in tension through stretching/sliding mechanisms, whereas other lamellae sympathetically rotate away from the tensile axis and compress, thereby enhancing the scale's ductility and toughness to prevent fracture. PMID:24129554

  7. ETUDE ET MODELISATION DU COMPORTEMENT ELASTIQUE D'UNE STRUCTURE SANDWICH DE TYPE CARTON ONDULE

    Allaoui, S.; Aboura, Z.; Benzeggagh, M.L.

    2003-01-01

    Le but de cette étude est de déterminer les propriétés homogénéisées d'une structure sandwich de type carton ondulé. La démarche adoptée est double. Elle aborde le problème d'une part, d'un point de vue expérimental en mettent au point une procédure adaptée à ce type de matériaux. Et d'autre part, elle établit un modèle analytique capable de prédire les propriétés élastiques dans le plan en fonction des paramètres structuraux. Les résultats obtenus corrélés à l'expérience ont donné satisfacti...

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

    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

    , 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...... 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.......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 (Znt...

  9. Numerical analysis of the discharge structures in non-equilibrium disk type MHD generator

    Discharge structures in the channel of a non-equilibrium disk type MHD generator have been studied by two-dimensional dynamic numerical analysis. (1) In the disk type Hall generator, discharge in the channel is non-uniform due to plasma ionization instability. (2) At low magnetic inductions, the discharge is non-uniform due to incomplete plasma seed ionization. At high magnetic inductions, it becomes uniform due to the complete seed ionization. (3) As compared with the linear channel Faraday generator, the disk channel Hall generator with internally short-circuited Faraday current is capable of high-efficiency plasma heating and so of suppressing the plasma ionization instability at low magnetic induction. (4) With decrease of the load resistance, the electron temperature lowers and also the electron density. (Mori, K.)

  10. Local equivalent welding element to predict the welding deformations of plate-type structures

    2008-01-01

    Considering the Heat Affected Zone (HAZ) of welding joint, the residual strain be-haviors of material under constraint and temperature circulation, as well as the activating mechanism of welding process, this paper addresses a new type welding element for numerical simulation of welding deformation, which is called the LEWE (the local equivalent welding element). This element can describe the basic char-acteristics of welded seam: the local position points of inherent strain, the equiva-lent size, the bending radius (or bending angle) from inherent strain, etc. It could be used to predict the welding deformation of plate-type structure. The comparisons between the computed deflection of welded plate and its experiment measurement are present. The results showed that the LEWE possesses a potential to simulate the deformation of welding process high-efficiently and precisely.

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

    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.

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

    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.

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

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

  14. Structure Design and Optimization of a New Type of Subsea Pipeline Connector

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

    2012-01-01

    The basic configuration of a new type of subsea pipeline connector was proposed based on the press-fitting principle,and a parametric fmite 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 canied out.The results indicate that the optimum structural design significantly improved the indicators of the minimum loading force and sealing performance of the connector.

  15. Hilbert space structures on the solution space of Klein-Gordon-type evolution equations

    We use the theory of pseudo-Hermitian operators to address the problem of the construction and classification of positive-definite invariant inner-products on the space of solutions of a Klein-Gordon-type evolution equation. This involves dealing with the peculiarities of formulating a unitary quantum dynamics in a Hilbert space with a time-dependent inner product. We apply our general results to obtain possible Hilbert space structures on the solution space of the equation of motion for a classical simple harmonic oscillator, a free Klein-Gordon equation and the Wheeler-DeWitt equation for the FRW-massive-real-scalar-field models

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

    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 an...

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

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

    2008-01-01

    equations in complex and curvilinear geometries which amends the application range of previous numerical models that have been based on structured Cartesian grids. The Boussinesq method provides the basis for the accurate description of fully nonlinear and dispersive water waves in both shallow and deep......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...

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

    MAGDALENA TOMASEVIC-CANOVIC

    2004-04-01

    Full Text Available Samples of natural HEU-type zeolites – clinoptilolite-Ca, from the Novakovici deposit (near Prijedor, Bosnia and Herzegovina were treated with the hydrochloric acid of various concentrations (from 10-3 M to 2 M. Zeolitic tuffs before and after the acid treatment were examined using IR, XRPD, and chemical analyses. The changes in the crystal structure of acid treated samples showed a significant reduction in the crystallinity of zeolitic tuffs (60–70 %, which were effected by hydrochloric acid with concentrations of 1 M and above.

  19. Ternary borides with CeNi12B6 type structure

    The well-known LnNi12B6 and ∼ LnNi12B7 (Ln-Y, La, Pr, Nd, Sm, Gd) and prepared for the first time LnNi12B6(Ln-Tb, Dy) borides are proved to possess the rhombic structure of CeNi12B6 type. The parameters of the elementary cells for all compounds are determined. Continuous change in the parameters points to the three-valent state of rare earth atoms

  20. Effect of culture conditions on the structure of Streptococcus pneumoniae type 19A(57) capsular polysaccharide.

    Lee, C.J.; Fraser, B A; Boykins, R A; Li, J P

    1987-01-01

    The structural modifications and immunochemical activities of several Streptococcus pneumoniae type 19A polysaccharide (PS) preparations have been studied by sugar compositional analysis and immunodiffusion. The 19A PS preparations Lab-A-1 and Lab-A-3 and one PS isolated from 19A strain OB contained fucose (Fuc) and galactose (Gal) in addition to rhamnose (Rha) and glucose (Glc). In contrast, 19A PSs Lab-A-2 and Lab-B contained only Rha and Glc. Despite their different sugar compositions, the...

  1. Reducing democratic type II supergravity on SU(3) x SU(3) structures

    Cassani, Davide

    2008-01-01

    Type II supergravity on backgrounds admitting SU(3) x SU(3) structure and general fluxes is considered. Using the generalized geometry formalism, we study dimensional reductions leading to N=2 gauged supergravity in four dimensions, possibly with tensor multiplets. In particular, a geometric formula for the full N=2 scalar potential is given. Then we implement a truncation ansatz, and derive the complete N=2 bosonic action. While the NSNS contribution is obtained via a direct dimensional reduction, the contribution of the RR sector is computed starting from the democratic formulation and demanding consistency with the reduced equations of motion.

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

    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

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

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

    1994-01-01

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

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

    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-δ (δ = 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-δ, Y1yCayBa2-yLayCu3-xFexO7-δ (y = 0.25, 0.5, x = 0.06, 0.12, δ≅ 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

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

    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.

  6. High frequency characteristics and modelling of p-type 6H-silicon carbide MOS structures

    Fernández, J.; Godignon, P.; Berberich, S.; Rebollo, J.; Brezeanu, G.; Millán, J.

    1996-09-01

    This paper presents the high frequency electrical characteristics and modelling of Al/SiO 2/ p-type 6HSiC structures. The oxide was thermally grown under dry conditions. Capacitance and conductance vs bias and frequency measurements have been performed in daylight and exposing the capacitors to u.v. light. The experimental Cm- Vg and Gm- Vg characteristics show hysteresis effects, which are more important when the samples are exposed to 254 nm u.v. light. This behaviour can be explained in terms of interface traps. The MOS structure modelling is based on an interface trap model in which the interface trap levels are considered to be continuously distributed in the SiC bandgap and only charge exchange between interface trap levels and the SiC bands is allowed. From this formulation and from the Gm- f characteristics, the interface state density and the interface trap time constant have been determined.

  7. New transition metal oxide fluorides with ReO{sub 3}-type structure

    Nakhal, Suliman; Lerch, Martin [Technische Universitaet Berlin (Germany). Inst. fuer Chemie

    2016-08-01

    The new niobium oxide fluorides MNbO{sub 2}F{sub 4} [M = (Cr, Fe)], CrNb{sub 2}O{sub 4}F{sub 5}, and Fe{sub 2}Nb{sub 3}O{sub 6}F{sub 9} were prepared by treatment of chromium or iron nitrate with Nb-containing hydrofluoric acid solutions. Crystal structures were investigated by means of X-ray powder diffraction. All new compounds can be structurally refined in the cubic ReO{sub 3}-type. The iron niobium oxide fluorides are reddish orange, and chromium containing phases exhibit a light green color. The niobium atoms are in the highest formal oxidation state.

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

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

    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.)

  10. Prediction, conservation analysis, and structural characterization of mammalian mucin-type O-glycosylation sites

    Julenius, Karin; Mølgaard, Anne; Gupta, Ramneek;

    2005-01-01

    experimentally investigated with regard to glycosylation status. From O-GLYCBASE a total of 86 mammalian proteins experimentally investigated for in vivo O-GalNAc sites were extracted. Mammalian protein homolog comparisons showed that a glycosylated serine or threonine is less likely to be precisely conserved...... than a nonglycosylated one. The Protein Data Bank was analyzed for structural information, and 12 glycosylated structures were obtained. All positive sites were found in coil or turn regions. A method for predicting the location for mucin-type glycosylation sites was trained using a neural network...... approach. The best overall network used as input amino acid composition, averaged surface accessibility predictions together with substitution matrix profile encoding of the sequence. To improve prediction on isolated (single) sites, networks were trained on isolated sites only. The final method combines...